## Recent Postings from Galaxies

### The Surface Density Profile of the Galactic Disk from the Terminal Velocity Curve

The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For $R_0 = 8$ kpc, the models have stellar mass $5 < M_* < 6 \times 10^{10}$ M$_{\odot}$, scale length $2.0 \le R_d \le 2.9$ kpc, LSR circular velocity $222 \le \Theta_0 \le 233$ km s$^{-1}$, and solar circle stellar surface density $34 \le \Sigma_d(R_0) \le 61$ M$_{\odot}$ pc$^{-2}$. The present inter-arm location of the solar neighborhood may have a somewhat lower stellar surface density than average for the solar circle. The Milky Way appears to be a normal spiral galaxy that obeys scaling relations like the Tully-Fisher relation, the size-mass relation, and the disk maximality-surface brightness relation. The stellar disk is maximal, and the spiral arms are massive. The bumps and wiggles in the terminal velocity curve correspond to known spiral features (e.g., the Centaurus Arm is a $\sim 50\%$ overdensity). The rotation curve switches between positive and negative over scales of hundreds of parsecs. The rms amplitude $\langle$$|$$dV/dR$$|^2$$\rangle$$^{1/2} \approx 14$ km s$^{-1}$ kpc$^{-1}$, implying that commonly neglected terms in the Jeans equations may be non-negligible. The spherically averaged local dark matter density is $\rho_{0,DM} \approx 0.009$ M$_{\odot}$ pc$^{-3}$ (0.3 GeV cm$^{-3}$). Adiabatic compression of the dark matter halo may help reconcile the Milky Way with the $c$-$V_{200}$ relation expected in $\Lambda$CDM while also helping to mitigate the too big to fail problem, but it remains difficult to reconcile the inner bulge/bar dominated region with a cuspy halo. We note that NGC 3521 is a near twin to the Milky Way, having a similar luminosity, scale length, and rotation curve.

### The Musca cloud: a 6 pc-long velocity-coherent, sonic filament

Filaments play a key role in the molecular clouds' evolution, but their internal dynamical properties remain poorly characterized. To further explore the physical state of these structures, we have investigated the kinematic properties of the Musca cloud. We have sampled the main axis of this filamentary cloud in $^{13}$CO and C$^{18}$O (2--1) lines using APEX observations. The different line profiles in Musca shows that this cloud presents a continuous and quiescent velocity field along its $\sim$6.5 pc of length. With an internal gas kinematics dominated by thermal motions (i.e. $\sigma_{NT}/c_s\lesssim1$) and large-scale velocity gradients, these results reveal Musca as the longest velocity-coherent, sonic-like object identified so far in the ISM. The (tran-)sonic properties of Musca present a clear departure from the predicted supersonic velocity dispersions expected in the Larson's velocity dispersion-size relationship, and constitute the first observational evidence of a filament fully decoupled from the turbulent regime over multi-parsec scales.

### Imprints of radial migration on the Milky Way's metallicity distribution functions

Recent analysis of the SDSS-III/APOGEE Data Release 12 stellar catalogue has revealed that the Milky Way's metallicity distribution function (MDF) changes shape as a function of radius, transitioning from being negatively skewed at small Galactocentric radii to positively skewed at large Galactocentric radii. Using a high resolution, N-body+SPH simulation, we show that the changing skewness arises from radial migration - metal-rich stars form in the inner disk and subsequently migrate to the metal-poorer outer disk. These migrated stars represent a large fraction (> 50%) of the stars in the outer disk; they populate the high metallicity tail of the MDFs and are, in general, more metal-rich than the surrounding outer disk gas. The simulation also reproduces another surprising APOGEE result: the spatially invariant high-[alpha/Fe] MDFs. This arises in the simulation from the migration of a population formed within a narrow range of radii (3.2+/-1.2 kpc) and time (8.8+/-0.6 Gyr ago), rather than from spatially extended star formation in a homogeneous medium at early times. These results point toward the crucial role radial migration has played in shaping our Milky Way.

### Spirality: A Novel Way to Measure Spiral Arm Pitch Angle

We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 minutes per galaxy, assuming at least 8 GB of working memory. We tested the code using 117 synthetic spiral images with known pitches, varying both the spiral properties and the input parameters. The code yielded correct results for all synthetic spirals with galaxy-like properties. We also compared the code's results to two-dimensional Fast Fourier Transform (2DFFT) measurements for the sample of nearby galaxies defined by DMS PPak. Spirality's error bars overlapped 2DFFT's error bars for 26 of the 30 galaxies. The two methods' agreement correlates strongly with galaxy radius in pixels and also with i-band magnitude, but not with redshift, a result that is consistent with at least some galaxies' spiral structure being fully formed by z=1.2, beyond which there are few galaxies in our sample. The Spirality code package also includes GenSpiral, which produces FITS images of synthetic spirals, and SpiralArmCount, which uses a one-dimensional Fast Fourier Transform to count the spiral arms of a galaxy after its pitch is determined. The code package is freely available online; see Comments for URL.

### Large-scale latitude distortions of the inner Milky Way Disk from the Herschel/Hi-GAL Survey

We use the Herschel Hi-GAL survey data to study the spatial distribution in Galactic longitude and latitude of the interstellar medium and of dense, star-forming clumps in the inner Galaxy. The peak position and width of the latitude distribution of the dust column density as well as of number density of compact sources from the band-merged Hi-GAL photometric catalogues are analysed as a function of longitude. The width of the diffuse dust column density traced by the Hi-GAL 500 micron emission varies across the inner Galaxy, with a mean value of 1{\deg}.2-1{\deg}.3, similar to that of the 250um Hi-GAL sources. 70um Hi-GAL sources define a much thinner disk, with a mean FWHM of 0{\deg}.75, and an average latitude of b=0{\deg}.06, coincident with the results from ATLASGAL. The GLAT distribution as a function of GLON shows modulations, both for the diffuse emission and for the compact sources, with ~0{\deg}.2 displacements mostly toward negative latitudes at l~ +40{\deg}, +12{\deg}, -25{\deg} and -40{\deg}. No such modulations can be found in the MIPSGAL 24 or WISE 22 um data when the entire source samples are considered. The distortions revealed by Herschel are interpreted as large-scale bending modes of the Plane. The lack of similar distortions in tracers of more evolved YSOs or stars rules out gravitational instabilities or satellite-induced perturbations, as they should act on both the diffuse and stellar disk components. We propose that the observed bends are caused by incoming flows of extra-planar gas interacting with the gaseous disk. Stars decouple from the gaseous ISM and relax into the stellar disk potential. The time required for the disappearance of the distortions from the diffuse ISM to the relatively evolved YSO stages are compatible with star-formation timescales.

### Synthetic HI observations of spiral structure in the outer disk in galaxies

By means of 3D hydrodynamical simulations, in a separate paper we have discussed the properties of non-axisymmetric density wave trains in the outermost regions of galaxy disks, based on the picture that self-excited global spiral modes in the bright optical stellar disk are accompanied by low-amplitude short trailing wave signals outside corotation; in the gas, such wave trains can penetrate through the outer Lindblad resonance and propagate outwards, forming prominent spiral patterns. In this paper we present the synthetic 21~cm velocity maps expected from simulated models of the outer gaseous disk, focusing on the case when the disk is dominated by a two-armed spiral pattern, but considering also other more complex situations. We discuss some aspects of the spiral pattern in the gaseous periphery of galaxy disks noted in our simulations that might be interesting to compare with specific observed cases.

### Magellan/M2FS Spectroscopy of Tucana 2 and Grus 1

We present results from spectroscopic observations with the Michigan/Magellan Fiber System (M2FS) of $147$ stellar targets along the line of sight to the newly-discovered ultrafaint' stellar systems Tucana 2 (Tuc 2) and Grus 1 (Gru 1). Based on simultaneous estimates of line-of-sight velocity and stellar-atmospheric parameters, we identify 8 and 7 stars as probable members of Tuc 2 and and Gru 1, respectively. Our sample for Tuc 2 is sufficient to resolve an internal velocity dispersion of $8.6_{-2.7}^{+4.4}$ km s$^{-1}$ about a mean of $-129.1_{-3.5}^{+3.5}$ km s$^{-1}$ (solar rest frame), and to estimate a mean metallicity of [Fe/H]= $-2.23_{-0.12}^{+0.18}$. These results place Tuc 2 on chemodynamical scaling relations followed by dwarf galaxies, suggesting a dominant dark matter component with dynamical mass $2.7_{-1.3}^{+3.1}\times 10^6$ $\mathrm{M}_{\odot}$ enclosed within the central $\sim 160$ pc, and dynamical mass-to-light ratio $1900_{-900}^{+2200}$ $\mathrm{M}_{\odot}/L_{V,\odot}$. For Gru 1 we estimate a mean velocity of $-140.5_{-1.6}^{+2.4}$ km s$^{-1}$ and a mean metallicity of [Fe/H]=$-1.42_{-0.42}^{+0.55}$, but our sample does not resolve Gru 1's velocity dispersion. The radial coordinates of Tuc 2 and Gru 1 in Galactic phase space suggest that their orbits are among the most energetic within distance $\leq 300$ kpc. Moreover, their proximity to each other in this space arises naturally if both objects are trailing the Large Magellanic Cloud.

### Mergers and the outside-in formation of dwarf spheroidals

We use a cosmological simulation of the formation of the Local Group to explore the origin of age and metallicity gradients in dwarf spheroidal galaxies. We find that a number of simulated dwarfs form "outside-in", with an old, metal-poor population that surrounds a younger, more concentrated metal-rich component, reminiscent of dwarf spheroidals like Sculptor or Sextans. We focus on a few examples where stars form in two populations distinct in age in order to elucidate the origin of these gradients. The spatial distributions of the two components reflect their diverse origin; the old stellar component is assembled through mergers, but the young population forms largely in situ. The older component results from a first episode of star formation that begins early but is quickly shut off by the combined effects of stellar feedback and reionization. The younger component forms when a late accretion event adds gas and reignites star formation. The effect of mergers is to disperse the old stellar population, increasing their radius and decreasing their central density relative to the young population. We argue that dwarf-dwarf mergers offer a plausible scenario for the formation of systems with multiple distinct populations and, more generally, for the origin of age and metallicity gradients in dwarf spheroidals.

### The HerMES sub-millimetre local and low-redshift luminosity functions

We used wide area surveys over 39 deg$^2$ by the HerMES collaboration, performed with the Herschel Observatory SPIRE multi-wavelength camera, to estimate the low-redshift, $0.02<z<0.5$, monochromatic luminosity functions (LFs) of galaxies at 250, 350 and 500$\,\mu$m. SPIRE flux densities were also combined with Spitzer photometry and multi-wavelength archival data to perform a complete SED fitting analysis of SPIRE detected sources to calculate precise k-corrections, as well as the bolometric infrared (8-1000$\,\mu$m) luminosity functions and their low-$z$ evolution from a combination of statistical estimators. Integration of the latter prompted us to also compute the local luminosity density (LLD) and the comoving star formation rate density (SFRD) for our sources, and to compare them with theoretical predictions of galaxy formation models. The luminosity functions show significant and rapid luminosity evolution already at low redshifts, $0.02<z<0.2$, with L$_{IR}^* \propto (1+z)^{6.0\pm0.4}$ and $\Phi_{IR}^* \propto (1+z)^{-2.1\pm0.4}$, L$_{250}^* \propto (1+z)^{5.3\pm0.2}$ and $\Phi_{250}^* \propto (1+z)^{-0.6\pm0.4}$ estimated using the IR bolometric and the 250$\,\mu$m LFs respectively. Converting our IR LD estimate into an SFRD assuming a standard Salpeter IMF and including the unobscured contribution based on the UV dust-uncorrected emission from local galaxies, we estimate a SFRD scaling of SFRD$_0+0.08 z$, where SFRD$_0\simeq (1.9\pm 0.03)\times 10^{-2} [\mathrm{M}_\odot\,\mathrm{Mpc}^{-3}]$ is our total SFRD estimate at $z\sim0.02$.

### Accretion Disc Time Lag Distributions: Applying CREAM to Simulated AGN Light Curves

Active Galactic Nuclei (AGN) vary in their brightness across all wavelengths. Moreover, longer wavelength ultraviolet - optical continuum light curves appear to be delayed with respect to shorter wavelength light curves. A simple way to model these delays is by assuming thermal reprocessing of a variable point source (a lamp post) by a blackbody accretion disc. We introduce a new method, CREAM (\textbf{C}ontinuum \textbf{RE}processed \textbf{A}GN \textbf{M}arkov Chain Monte Carlo), that models continuum variations using this lamp post model. The disc light curves lag the lamp post emission with a time delay distribution sensitive to the disc temperature-radius profile and inclination. We test CREAM's ability to recover both inclination and product of black hole mass and accretion rate $\mmdot$, and show that the code is also able to infer the shape of the driving light curve. CREAM is applied to synthetic light curves expected from 1000 second exposures of a 17th magnitude AGN with a 2m telescope in Sloan g and i bands with signal to noise of 500 - 900 depending on the filter and lunar phase. We also tests CREAM on poorer quality g and i light curves with SNR = 100. We find in the high SNR case that CREAM can recover the accretion disc inclination to within an uncertainty of 5 degrees and an $\mmdot$ to within 0.04 dex.

### Supermassive star formation via episodic accretion: protostellar disc instability and radiative feedback efficiency

The formation of SMSs is a potential pathway to seed SMBHs in the early universe. A critical issue for forming SMSs is stellar UV feedback, which may limit the stellar mass growth via accretion. In this paper we study the evolution of an accreting SMS and its UV emissivity under conditions of realistic variable accretion from a self-gravitating circumstellar disc. First we conduct a 2D hydrodynamical simulation to follow the long-term protostellar accretion until the stellar mass exceeds $10^4~M_\odot$. The disc fragments due to gravitational instability, creating a number of small clumps that rapidly migrate inward to fall onto the star. The resulting accretion history is thus highly time-dependent: short episodic accretion bursts are followed by longer, relative quiescent phases. We show that the circumstellar disc for the so-called direct collapse model is more unstable and generates greater variability over shorter timescales than normal Pop III cases. We conduct a post-process stellar evolution calculation using the obtained accretion history. Our results show that, regardless of the strong variability of the accretion rates, the stellar radius monotonically increases with almost constant effective temperature at $T_{\rm eff} \simeq 5000$ K as the stellar mass increases. The resulting UV feedback is too weak to hinder mass accretion due to the low flux of stellar UV photons, thus verifying our implicit assumption of no stellar feedback during the hydrodynamic simulations. The insensitivity of stellar evolution to variable accretion is attributed to the fact that typical timescales of variability, $\lesssim 10^3$ years, are too short to affect the stellar structure. We argue that this evolution will continue until the SMS eventually collapses to produce a massive black hole by the general relativistic instability after the stellar mass reaches $\gtrsim 10^5~M_\odot$.

### The Influence of a Kinematically Cold Young Component on Disc-Halo Decompositions in Spiral Galaxies: Insights from Solar Neighbourhood K-giants

In decomposing the HI rotation curves of disc galaxies, it is necessary to break a degeneracy between the gravitational fields of the disc and the dark halo by estimating the disc surface density. This is done by combining measurements of the vertical velocity dispersion of the disc with the disc scale height. The vertical velocity dispersion of the discs is measured from absorption lines (near the V-band) of near-face-on spiral galaxies, with the light coming from a mixed population of giants of all ages. However, the scale heights for these galaxies are estimated statistically from near-IR surface photometry of edge-on galaxies. The scale height estimate is therefore dominated by a population of older (> 2 Gyr) red giants. In this paper, we demonstrate the importance of measuring the velocity dispersion for the same older population of stars that is used to estimate the vertical scale height. We present an analysis of the vertical kinematics of K-giants in the solar vicinity. We find the vertical velocity distribution best fit by two components with dispersions of 9.6 +/- 0.5 km/s and 18.6 +/- 1.0 km/s, which we interpret as the dispersions of the young and old disc populations respectively. Combining the (single) measured velocity dispersion of the total young + old disc population (13.0 +/- 0.1 km/s) with the scale height estimated for the older population would underestimate the disc surface density by a factor of ~ 2. Such a disc would have a peak rotational velocity that is only 70% of that for the maximal disc, thus making it appear submaximal.

### Hubble Tarantula Treasury Project. III. Photometric Catalog and Resulting Constraints on the Progression of Star Formation in the 30 Doradus Region

We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope (HST) Treasury program designed to image the entire 30 Doradus region down to the sub-solar (~0.5 solar masses) mass regime using the Wide Field Camera 3 (WFC3) and the Advanced Camera for Surveys (ACS). We observed 30 Doradus in the near ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function (PSF) fitting across all the bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog, results from artificial star experiments and the mosaics for all the filters are available for download. Color-magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate and low mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant HII region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset towards our side of the Large Magellanic Cloud.

### Mutual distance dependence drives the observed jet power - radio luminosity scaling relations in radio galaxies

The kinetic power of radio jets is a quantity of fundamental importance to studies of the AGN feedback process and radio galaxy physics. A widely used proxy for jet power is the extended radio luminosity. A number of empirical methods have been used to calibrate a scaling relationship between jet power (Q) and radio luminosity (L) of the form log(Q) = beta_L * log(L) + C. The regression slope has typically been found to be beta_L ~ 0.7 - 0.8. Here we show that the previously reported scaling relations are strongly affected by the confounding variable, distance. We find that in a sample of FRI X-ray cavity systems, after accounting for the mutual distance dependence, the jet power and radio luminosity are only weakly correlated, with slope beta_L ~ 0.3: significantly flatter than previously reported. We also find that in previously used samples of high-power sources, no evidence for an intrinsic correlation is present when the effect of distance is accounted for. Using a simple model we show that beta_L is expected to be significantly lower in samples of FRI radio galaxies than it is for FRIIs, due to the differing dynamics for these two classes of radio source. For FRI X-ray cavity systems the model predicts beta_L (FRI) ~ 0.5 in contrast to FRII radio galaxies, for which beta_L(FRII) ~ 0.8. We discuss the implications of our finding for studies of radio mode feedback, and radio galaxy physics.

### HI and CO Velocity Dispersions in Nearby Galaxies

We analyze the velocity dispersions of individual HI and CO profiles in a number of nearby galaxies from the high-resolution HERACLES CO and THINGS HI surveys. Focusing on regions with bright CO emission, we find a CO dispersion value: 7.3 $\pm$ 1.7 km/s. The corresponding HI dispersion is 11.7 $\pm$ 2.3 km/s, yielding a mean HI/CO dispersion ratio of 1.4 $\pm$ 0.2, independent of radius. We find that the CO velocity dispersion increases towards lower peak fluxes. This is consistent with previous work where we showed that when using spectra averaged ("stacked") over large areas, larger values for the CO dispersion are found, and a lower dispersion ratio: 1.0 $\pm$ 0.2. The stacking method is more sensitive to low-level diffuse emission, whereas individual profiles trace narrow-line, GMC-dominated, bright emission. These results provide further evidence that disk galaxies contain not only a thin, low velocity dispersion, high density CO disk that is dominated by GMCs, but also a fainter, higher dispersion, diffuse disk component.

### Anomalous Microwave Emission from Spinning Dust and its Polarization Spectrum

Nearly twenty years after the discovery of anomalous microwave emission (AME) that contaminates to the cosmic microwave background (CMB) radiation, its origin remains inconclusive. Observational results from numerous experiments have revealed that AME is most consistent with spinning dust emission from rapidly spinning ultrasmall interstellar grains. In this paper, I will first review our improved model of spinning dust, which treats realistic dynamics of wobbling non-spherical grains, impulsive interactions of grains with ions in the ambient plasma, and some other important effects. I will then discuss recent progress in quantifying the polarization of spinning dust emission from polycyclic aromatic hydrocarbons. I will finish with a brief discussion on remaining issues about the origins of AME.

### Fossil groups in the Millennium simulation. From the brightest to the faintest galaxies during the past 8 Gyr

We investigate the evolution of bright and faint galaxies in fossil and non-fossil groups. We used mock galaxies constructed based on the Millennium run simulation II. We identified fossil groups at redshift zero according to two different selection criteria, and then built reliable control samples of non-fossil groups that reproduce the fossil virial mass and assembly time distributions. The faint galaxies were defined as having r-band absolute magnitudes in the range [-16,-11]. We analysed the properties of the bright and faint galaxies in fossil and non-fossil groups during the past 8 Gyr. We observed that the brightest galaxy in fossil groups is typically brighter and more massive than their counterparts in control groups. Fossil groups developed their large magnitude gap between the brightest galaxies around 3.5 Gyr ago. The brightest galaxy stellar masses of all groups show a notorious increment at that time. By analysing the behaviour of the magnitude gap between the first and the second, third, and fourth ranked galaxies, we found that at earlier times, fossil groups comprised two large brightest galaxies with similar magnitudes surrounded by much fainter galaxies, while in control groups these magnitude gaps were never as large as in fossils. At early times, fossil groups in the faint population were denser than non-fossil groups, then this trend reversed, and finally they became similar at the present day. The mean number of faint galaxies in non-fossil systems increases in an almost constant rate towards later times, while this number in fossil groups reaches a plateau at $z\sim0.6$ that lasts $\sim 2$ Gyr, and then starts growing again more rapidly. The formation of fossil groups is defined at the very beginning of the groups according to their galaxy luminosity sampling, which could be determined by their merging rate at early times.

### Star Formation Suppression Due to Jet Feedback in Radio Galaxies with Shocked Warm Molecular Gas

We present Herschel observations of 22 radio galaxies, selected for the presence of shocked, warm molecular hydrogen emission. We measured and modeled spectral energy distributions (SEDs) in 33 bands from the ultraviolet to the far-infrared to investigate the impact of jet feedback on star formation activity. These galaxies are massive, early-type galaxies with normal gas-to-dust ratios, covering a range of optical and IR colors. We find that the star formation rate (SFR) is suppressed by a factor of ~3-6, depending on how molecular gas mass is estimated. We suggest this suppression is due to the shocks driven by the radio jets injecting turbulence into the interstellar medium (ISM), which also powers the luminous warm H2 line emission. Approximately 25% of the sample shows suppression by more than a factor of 10. However, the degree of SFR suppression does not correlate with indicators of jet feedback including jet power, diffuse X-ray emission, or intensity of warm molecular H2 emission, suggesting that while injected turbulence likely impacts star formation, the process is not purely parametrized by the amount of mechanical energy dissipated into the ISM. Radio galaxies with shocked warm molecular gas cover a wide range in SFR-stellar mass space, indicating that these galaxies are in a variety of evolutionary states, from actively star-forming and gas-rich to quiescent and gas-poor. SFR suppression appears to have the biggest impact on the evolution of galaxies that are moderately gas-rich.

### Evolution of velocity dispersion along cold collisionless flows

The infall of cold dark matter onto a galaxy produces cold collisionless flows and caustics in its halo. If a signal is found in the cavity detector of dark matter axions, the flows will be readily apparent as peaks in the energy spectrum of photons from axion conversion, allowing the densities, velocity vectors and velocity dispersions of the flows to be determined. We discuss the evolution of velocity dispersion along cold collisionless flows in one and two dimensions. A technique is presented for obtaining the leading behaviour of the velocity dispersion near caustics. The results are used to derive an upper limit on the energy dispersion of the Big Flow from the sharpness of its nearby caustic, and a prediction for the dispersions in its velocity components.

### The Contribution of Host Galaxies to the Infrared Energy Output of $z\gtrsim5.0$ QUASARS

The infrared spectral energy distributions (SEDs) of $z\gtrsim 5$ quasars can be reproduced by combining a low-metallicity galaxy template with a standard AGN template. The host galaxy is represented by Haro 11, a compact, moderately low metallicity, star-bursting galaxy that shares typical features of high-$z$ galaxies. For the vast majority of $z\gtrsim 5$ quasars, the AGN contribution is well modeled by a standard empirical template with the contamination of star formation in the infrared subtracted. Together, these two templates can separate the contributions from the host galaxy and the AGN even in the case of limited data points, given that this model has only two free parameters. Using this method, we re-analyze 69 $z\gtrsim 5$ quasars with extensive Herschel observations, and derive their AGN luminosities $L_{\rm AGN}$ in a range $\sim (0.78-27.4) \times10^{13}\, L_{\odot}$, the infrared luminosities from star formation $L_{\rm SF,IR} \sim (<1.5-25.7)\times10^{12}\, L_{\odot}$, and the corresponding star formation rates ${\rm SFR}\sim (<290-2650)\, M_\odot/{\rm yr}$. The average infrared luminosity from star formation and the average total AGN luminosity of the $z\gtrsim5$ quasar sample follows the correlation defined by quasars at $z < 2.6$. We assume these quasar host galaxies maintain a constant average SFR ($\sim620\, M_\odot/{\rm yr}$) during their mass assembly and estimate the stellar mass that could form till $z\sim5-6$ to be $\langle M_* \rangle \sim(3-5)\times10^{11} M_\odot$. Combining with the black hole (BH) mass measurements, this stellar mass is adequate to establish a BH-galaxy mass ratio $M_{\rm BH}/M_{*}$ at 0.1-1%, consistent with the local relation.

### Comparison of Hipparcos Trigonometric and Mount Wilson Spectroscopic Parallaxes for 90 Subgiants that Defined the Class in 1935

A history is given of the discovery between 1914 and 1935 of stars of intermediate luminosity between giants and dwarfs with spectral types between G0 to K3. The Mt Wilson spectroscopists identified about 90 such stars in their 1935 summary paper of spectroscopic absolute magnitudes for 4179 stars. Called "subgiants" by Str\"omberg, these 90 stars defined the group at the time. The position of the Mt Wilson subgiants in the HR diagram caused difficulties in comparisons of high weight trigonometric parallaxes being measured and with Russell's prevailing evolution proposal, and critics questioned the reality of the Mt Wilson subgiants. We compare, star-by-star, the Mt Wilson spectroscopic absolute magnitudes of the 90 stars defining their sample against those absolute magnitudes derived from Hipparcos (HIP) trigonometric parallaxes. We address concerns over biases in the Mt Wilson calibration sample and biases created by the adopted methodology for calibration. Historically, these concerns were sufficient to discredit the discovery of subgiants in the Mt Wilson sample. However, as shown here, the majority of the Mount Wilson stars identified as subgiants that also have reliable HIP trigonometric parallaxes do lie among the subgiant sequence in the HIP HR diagram. Moreover, no significant offset is seen between the M(V) brightnesses derived from the Mt Wilson spectroscopic parallaxes and the M(V) values derived from Hipparcos trigonometric parallaxes with a fractional error of 10%, which confirms in an impressive manner the efficacy of the original Mt Wilson assessments. The existence of subgiants proved that Russell's contraction proposal for stellar evolution from giants to the main sequence was incorrect. Instead, Gamow's 1944 unpublished conjecture that subgiants are post main-sequence stars just having left the main sequence was very nearly correct but was a decade before its time.

### Collisions between Dark Matter Confined High Velocity Clouds and Magnetized Galactic Disks: The Smith Cloud

The Galaxy's population of High Velocity Clouds (HVCs) may include a subpopulation that is confined by dark matter minihalos and falling toward the Galactic disk. We present the first magnetohydrodynamic simulational study of dark matter-dominated HVCs colliding with a weakly magnetized galactic disk. Our HVCs have baryonic masses of $5 \times 10^6\,$M$_{\odot}$ and dark matter minihalo masses of 0, $3 \times 10^8$, or $1 \times 10^9\,$M$_{\odot}$. They are modeled on the Smith Cloud, which is said to have collided with the disk 70 Myr ago. We find that, in all cases, the cloud's collision with the galactic disk creates a hole in the disk, completely disperses the cloud, and forms a bubble-shaped structure on the far side of the disk. In contrast, when present, the dark matter minihalo continues unimpeded along its trajectory. Later, as the minihalo passes through the bubble structure and galactic halo, it accretes up to $6.0 \times 10^5\,$M$_{\odot}$ in baryonic material, depending on the strengths of the magnetic field and minihalo gravity. These simulations suggest that if the Smith Cloud is associated with a dark matter minihalo and collided with the Galactic disk, the minihalo has accreted the observed gas. However, if the Smith Cloud is dark matter-free, it is on its first approach toward the disk. These simulations also suggest that the dark matter is most concentrated either at the head of the cloud or near the cloud, depending upon the strength of the magnetic field, a point that could inform indirect dark matter searches.

### The matter distribution in the local universe as derived from galaxy groups in SDSS DR12 and 2MRS [Replacement]

Context. Friends-of-friends algorithms are a common tool to detect galaxy groups and clusters in large survey data. For them to be as precise as possible, they have to be carefully calibrated using mock-catalogues. Aims. To create an accurate and robust description of the matter distribution in the local universe using the most up-to-date available data. This will provide input for a specific cosmological test planned as follow-up to this work, and will be useful for general extra- galactic and cosmological research. Methods. We create a set of galaxy group catalogues based on the 2MRS and SDSS DR12 catalogues using a friends-of-friends based group finder algorithm. The algorithm is carefully calibrated and optimised on a new set of wide-angle mock catalogues from the Millennium simulation, such as to provide accurate total mass estimates of the galaxy groups taking into account the relevant observational biases in 2MRS and SDSS. Results. We provide four different catalogues: 1) a 2MRS based group catalogue; 2) a SDSS DR12 based group catalogue reaching out to a redshift of 0.11; 3) a catalogue providing additional fundamental plane distances for all groups of the SDSS catalogue that host elliptical galaxies; 4) a catalogue of the mass distribution in the local universe based on a combination of our 2MRS and SDSS catalogues. The latter catalogue is especially designed for a specific cosmological test planned as follow-up to this work. Conclusions. While motivated by a specific cosmological test, three of the four catalogues that we produced are well suited to act as reference databases for a variety of extragalactic and cosmological science cases. Our catalogue of fundamental plane distances for SDSS groups provides further added value to this paper.

### The matter distribution in the local universe as derived from galaxy groups in SDSS DR12 and 2MRS

Context. Friends-of-friends algorithms are a common tool to detect galaxy groups and clusters in large survey data. For them to be as precise as possible, they have to be carefully calibrated using mock-catalogues. Aims. To create an accurate and robust description of the matter distribution in the local universe using the most up-to-date available data. This will provide input for a specific cosmological test planned as follow-up to this work, and will be useful for general extra- galactic and cosmological research. Methods. We create a set of galaxy group catalogues based on the 2MRS and SDSS DR12 catalogues using a friends-of-friends based group finder algorithm. The algorithm is carefully calibrated and optimised on a new set of wide-angle mock catalogues from the Millennium simulation, such as to provide accurate total mass estimates of the galaxy groups taking into account the relevant observational biases in 2MRS and SDSS. Results. We provide four different catalogues: 1) a 2MRS based group catalogue; 2) a SDSS DR12 based group catalogue reaching out to a redshift of 0.11; 3) a catalogue providing additional fundamental plane distances for all groups of the SDSS catalogue that host elliptical galaxies; 4) a catalogue of the mass distribution in the local universe based on a combination of our 2MRS and SDSS catalogues. The latter catalogue is especially designed for a specific cosmological test planned as follow-up to this work. Conclusions. While motivated by a specific cosmological test, three of the four catalogues that we produced are well suited to act as reference databases for a variety of extragalactic and cosmological science cases. Our catalogue of fundamental plane distances for SDSS groups provides further added value to this paper.

### The Magellanic Stream: Circumnavigating the Galaxy

The Magellanic Clouds are surrounded by an extended network of gaseous structures. Chief among these is the Magellanic Stream, an interwoven tail of filaments trailing the Clouds in their orbit around the Milky Way. When considered in tandem with its Leading Arm, the Stream stretches over 200 degrees on the sky. Thought to represent the result of tidal interactions between the Clouds and ram-pressure forces exerted by the Galactic corona, its kinematic properties reflect the dynamical history of the closest pair of dwarf galaxies to the Milky Way. The Stream is a benchmark for hydrodynamical simulations of accreting gas and cloud/corona interactions. If the Stream survives these interactions and arrives safely in the Galactic disk, its cargo of over a billion solar masses of gas has the potential to maintain or elevate the Galactic star formation rate. In this article, we review the current state of knowledge of the Stream, including its chemical composition, physical conditions, origin, and fate. We also review the dynamics of the Magellanic System, including the proper motions and orbital history of the Large and Small Magellanic Clouds, the first-passage and second-passage scenarios, and the evidence for a Magellanic Group of galaxies.

### A population of intermediate-mass black holes in dwarf starburst galaxies up to redshift=1.5

We study a sample of $\sim$50,000 dwarf starburst and late-type galaxies drawn from the COSMOS survey with the aim of investigating the presence of nuclear accreting black holes (BHs) as those seed BHs from which supermassive BHs could grow in the early Universe. We divide the sample into five complete redshift bins up to $z=1.5$ and perform an X-ray stacking analysis using the \textit{Chandra} COSMOS-Legacy survey data. After removing the contribution from X-ray binaries and hot gas to the stacked X-ray emission, we still find an X-ray excess in the five redshift bins that can be explained by nuclear accreting BHs. This X-ray excess is more significant for $z<0.5$. At higher redshifts, these active galactic nuclei could suffer mild obscuration, as indicated by the analysis of their hardness ratios. The average nuclear X-ray luminosities in the soft band are in the range 10$^{39}-10^{40}$ erg s$^{-1}$. Assuming that the sources accrete at $\geq$ 1\% the Eddington rate, their BH masses would be $\leq$ 10$^{5}$ M$_{\odot}$, thus in the intermediate-mass BH regime, but their mass would be smaller than the one predicted by the BH-stellar mass relation. If instead the sources follow the correlation between BH mass and stellar mass, they would have sub-Eddington accreting rates of $\sim$ 10$^{-3}$ and BH masses 1-9 $\times$ 10$^{5}$ M$_{\odot}$. We thus conclude that a population of intermediate-mass BHs exists in dwarf starburst galaxies, at least up to $z$=1.5, though their detection beyond the local Universe is challenging due to their low luminosity and mild obscuration unless deep surveys are employed.

### Gas accretion from halos to disks: observations, curiosities, and problems

Accretion of gas from the cosmic web to galaxy halos and ultimately their disks is a prediction of modern cosmological models but is rarely observed directly or at the full rate expected from star formation. Here we illustrate possible large-scale cosmic HI accretion onto the nearby dwarf starburst galaxy IC10, observed with the VLA and GBT. We also suggest that cosmic accretion is the origin of sharp metallicity drops in the starburst regions of other dwarf galaxies, as observed with the 10-m GTC. Finally, we question the importance of cosmic accretion in normal dwarf irregulars, for which a recent study of their far-outer regions sees no need for, or evidence of, continuing gas buildup.

### Theoretical considerations for star formation at low and high redshift

Star formation in strongly self-gravitating cloud cores should be similar at all redshifts, forming single or multiple stars with a range of masses determined by local magneto-hydrodynamics and gravity. The formation processes for these cores, however, as well as their structures, temperatures, Mach numbers, etc., and the boundedness and mass distribution functions of the resulting stars, should depend on environment, as should the characteristic mass, density, and column density at which cloud self-gravity dominates other forces. Because the environments for high and low redshift star formation differ significantly, we expect the resulting gas to stellar conversion details to differ also. At high redshift, the universe is denser and more gas-rich, so the active parts of galaxies are denser and more gas rich too, leading to slightly shorter gas consumption timescales, higher cloud pressures, and denser, more massive, bound stellar clusters at the high mass end. With shorter consumption times corresponding to higher relative cosmic accretion rates, and with the resulting higher star formation rates and their higher feedback powers, the ISM has greater turbulent speeds relative to the rotation speeds, thicker gas disks, and larger cloud and star complex sizes at the characteristic Jeans length. The result is a more chaotic appearance at high redshift, bridging the morphology gap between today's quiescent spirals and today's major-mergers, with neither spiral nor major-merger processes actually in play at that time. The result is also a thick disk at early times, and after in-plane accretion from relatively large clump torques, a classical bulge. Today's disks are thinner, and torque-driven accretion is slower outside of inner barred regions. This paper reviews the basic processes involved with star formation in order to illustrate its evolution over time and environment.

### Threshold Energies for Single Carbon Knockout from Polycyclic Aromatic Hydrocarbons [Cross-Listing]

We have measured absolute cross sections for ultrafast (fs) single-carbon knockout from Polycyclic Aromatic Hydrocarbon (PAH) cations as functions of He-PAH center-of-mass collision energy in the range 10-200 eV. Classical Molecular Dynamics (MD) simulations cover this range and extend up to 10$^5$ eV. The shapes of the knockout cross sections are well described by a simple analytical expression yielding experimental and MD threshold energies of $E_{th}^{Exp}=32.5\pm 0.4$ eV and $E_{th}^{MD}=41.0\pm 0.3$ eV, respectively. These are the first measurements of knockout threshold energies for molecules isolated \emph{in vacuo}. We further deduce semi-empirical (SE) and MD displacement energies --- \emph{i.e.} the energy transfers to the PAH molecules at the threshold energies for knockout --- of $T_{disp}^{SE}=23.3\pm 0.3$ eV and $T_{disp}^{MD}=27.0\pm 0.3$ eV. The semi-empirical results compare favorably with measured displacement energies for graphene $T_{disp}=23.6$ eV [Meyer \emph{et al.} Phys. Rev Lett. \textbf{108} 196102 (2012) and \textbf{110} 239902 (2013)].

### Exploring Molecular Complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)

Deuteration is a powerful tracer of the history of the cold prestellar phase in star forming regions. Apart from methanol, little is known about deuterium fractionation of complex organic molecules in the interstellar medium, especially in high mass star forming regions. We use a spectral line survey performed with ALMA to search for deuterated complex organic molecules toward the hot molecular core Sgr B2(N2). Population diagrams and integrated intensity maps are constructed to fit rotational temperatures and emission sizes for each molecule. Column densities are derived by modelling the full spectrum under the LTE assumption. The results are compared to predictions of two astrochemical models that treat the deuteration process. We report the detection of CH2DCN toward Sgr B2(N2) with a deuteration level of 0.4%, and tentative detections of CH2DOH, CH2DCH2CN, the chiral molecule CH3CHDCN, and DC3N with levels in the range 0.05%-0.12%. A stringent deuteration upper limit is obtained for CH3OD (<0.07%). Upper limits in the range 0.5-1.8% are derived for the three deuterated isotopologues of vinyl cyanide, the four deuterated species of ethanol, and CH2DOCHO. Ethyl cyanide is less deuterated than methyl cyanide by at least a factor five. Except for methyl cyanide, the measured deuteration levels lie at least a factor four below the predictions of current astrochemical models. The deuteration levels in Sgr B2(N2) are also lower than in Orion KL by a factor of a few up to a factor ten. The discrepancy between the deuteration levels of Sgr B2(N2) and the predictions of chemical models, and the difference between Sgr B2(N2) and Orion KL may both be due to the higher kinetic temperatures that characterize the Galactic Center region compared to nearby clouds. Alternatively, they may result from a lower overall abundance of deuterium itself in the Galactic Center region by up to a factor ten.

### Clear evidence for the presence of second-generation asymptotic giant branch stars in metal-poor Galactic globular clusters

Galactic globular clusters (GCs) are known to host multiple stellar populations: a first generation with a chemical pattern typical of halo field stars and a second generation (SG) enriched in Na and Al and depleted in O and Mg. Both stellar generations are found at different evolutionary stages (e.g., the main-sequence turnoff, the subgiant branch, and the red giant branch). The non detection of SG asymptotic giant branch (AGB) stars in several metal-poor ([Fe/H] < -1) GCs suggests that not all SG stars ascend the AGB phase, and that failed AGB stars may be very common in metal-poor GCs. This observation represents a serious problem for stellar evolution and GC formation/evolution theories. We report fourteen SG-AGB stars in four metal-poor GCs (M 13, M 5, M 3, and M 2) with different observational properties: horizontal branch (HB) morphology, metallicity, and age. By combining the H-band Al abundances obtained by the APOGEE survey with ground-based optical photometry, we identify SG Al-rich AGB stars in these four GCs and show that Al-rich RGB/AGB GC stars should be Na-rich. Our observations provide strong support for present, standard stellar models, i.e., without including a strong mass-loss efficiency, for low-mass HB stars. In fact, current empirical evidence is in agreement with the predicted distribution of FG and and SG stars during the He-burning stages based on these standard stellar models.

### CO Gas orbiting around the GG Tauri A triple System: rings beyond the ring ?

We aim at unveiling the observational imprint of physical mechanisms that govern planetary formation in the young, multiple system GG Tau A. We present ALMA observations of $^{12}$CO and $^{13}$CO 3-2 and continuum at 0.9 mm at 0.35" resolution. The $^{12}$CO gas, found in the cavity of the dust ring where no $^{13}$CO gas is detected, confirms the existence of a CO accretion shock near the circumstellar disk of GG Tau Aa. The outer disk and the hot spot lying at the outer edge of the dust ring are observed both in $^{12}$CO and $^{13}$CO. The gas emission in the outer disk can be radially decomposed in a series of slightly overlapping gaussian rings, suggesting the presence of unresolved gaps. The dip closest to the disk center lies at a radius very close to the CO hot spot location ($\sim250-260$~au). Studies of the CO excitation conditions reveal that the outer disk remains in the shadow of the ring. The hot spot probably results from local heating processes. The two latter points strongly support the hypothesis making the hot spot an embedded proto-planet shepherding the outer disk and accreting surrounding material which may be traced by the the redshifted component observed in the spectra around the hot spot.

### Gravitational acceleration and tidal effects in spherical-symmetric density profiles

Pure power-law density profiles, $\rho(r)\propto r^{b-3}$, are classified in connection with the following reference cases: (i) isodensity, $b=3$, $\rho=$ const; (ii) isogravity, $b=2$, $g=$ const; (iii) isothermal, $b=1$, $v=[GM(r)/r]^{1/2}=$ const; (iv) isomass, $b=0$, $M=$ const. A restricted number of different families of density profiles including, in addition, cored power-law, generalized power-law, polytropes, are studied in detail with regard to both one-component and two-component systems. Considerable effort is devoted to the existence of an extremum point (maximum absolute value) in the gravitational acceleration within the matter distribution. Predicted velocity curves are compared to the data inferred from observations. Tidal effects on an inner subsystem are investigated and an application is made to globular clusters within the Galaxy. To this aim, the tidal radius is defined by balancing the opposite gravitational forces from the Galaxy and the selected cluster on a special point of the cluster boundary, lying between related centres of mass. The position of 17 globular clusters with respect to the stability region, where the tidal radius exceeds the observed radius, is shown for assigned dark-to-visible mass ratios and density profiles, among those considered, which are currently used for the description of galaxies and/or dark matter haloes.

### Explaining the reportedly over-massive black holes in early-type galaxies with intermediate-scale discs [Replacement]

The classification "early-type" galaxy includes both elliptically- and lenticular-shaped galaxies. Theoretically, the spheroid-to-disc flux ratio of an early-type galaxy can assume any positive value, but in practice studies often consider only spheroid/disc decompositions in which the disc neatly dominates over the spheroid at large galaxy radii, creating an inner "bulge" as observed in most spiral galaxies. Here we show that decompositions in which the disc remains embedded within the spheroid, labelled by some as "unphysical", correctly reproduce both the photometric and kinematic properties of early-type galaxies with intermediate-scale discs. Intermediate-scale discs have often been confused with large-scale discs and incorrectly modelled as such; when this happens, the spheroid luminosity is considerably underestimated. This has recently led to some surprising conclusions, such as the claim that a number of galaxies with intermediate-scale discs (Mrk 1216, NGC 1277, NGC 1271, and NGC 1332) host a central black hole whose mass is abnormally large compared to expectations from the (underestimated) spheroid luminosity. We show that when these galaxies are correctly modelled, they no longer appear as extreme outliers in the (black hole mass)-(spheroid mass) diagram. This not only nullifies the need for invoking different evolutionary scenarios for these galaxies but it strengthens the significance of the observed (black hole mass)-(spheroid mass) correlation and confirms its importance as a fundamental ingredient for theoretical and semi-analytic models used to describe the coevolution of spheroids and their central supermassive black holes.

### Explaining the reportedly over-massive black holes in early-type galaxies with intermediate-scale discs

The classification "early-type" galaxy includes both elliptically- and lenticular-shaped galaxies. Theoretically, the spheroid-to-disc flux ratio of an early-type galaxy can assume any positive value, but in practice studies often consider only spheroid/disc decompositions in which the disc neatly dominates over the spheroid at large galaxy radii, creating an inner "bulge" as observed in most spiral galaxies. Here we show that decompositions in which the disc remains embedded within the spheroid, labelled by some as "unphysical", correctly reproduce both the photometric and kinematic properties of early-type galaxies with intermediate-scale discs. Intermediate-scale discs have often been confused with large-scale discs and incorrectly modelled as such; when this happens, the spheroid luminosity is considerably underestimated. This has recently led to some surprising conclusions, such as the claim that a number of galaxies with intermediate-scale discs (Mrk 1216, NGC 1277, NGC 1271, and NGC 1332) host a central black hole whose mass is abnormally large compared to expectations from the (underestimated) spheroid luminosity. We show that when these galaxies are correctly modelled, they no longer appear as extreme outliers in the (black hole mass)-(spheroid mass) diagram. This not only nullifies the need for invoking different evolutionary scenarios for these galaxies but it strengthens the significance of the observed (black hole mass)-(spheroid mass) correlation and confirms its importance as a fundamental ingredient for theoretical and semi-analytic models used to describe the coevolution of spheroids and their central supermassive black holes.

### On the Star Formation Law for Spiral and Irregular Galaxies

A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical time scale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical time scale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ~100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.

### Globular Cluster Populations: Results Including S$^4$G Late-Type Galaxies

Using 3.6 and 4.5$\mu$m images of 73 late-type, edge-on galaxies from the S$^4$G survey, we compare the richness of the globular cluster populations of these galaxies to those of early type galaxies that we measured previously. In general, the galaxies presented here fill in the distribution for galaxies with lower stellar mass, M$_*$, specifically $\log({\rm M}_*/{\rm M}_\odot) < 10$, overlap the results for early-type galaxies of similar masses, and, by doing so, strengthen the case for a dependence of the number of globular clusters per $10^9\ {\rm M}_\odot$ of galaxy stellar mass, T$_{\rm N}$, on M$_*$. For $8.5 < \log ({\rm M}_*/{\rm M}_\odot) < 10.5$ we find the relationship can be satisfactorily described as T$_{\rm N} = ({\rm M}_*/10^{6.7})^{-0.56}$ when M$_*$ is expressed in solar masses. The functional form of the relationship is only weakly constrained and extrapolation outside this range is not advised. Our late-type galaxies, in contrast to our early-types, do not show the tendency for low mass galaxies to split into two T$_{\rm N}$ families. Using these results and a galaxy stellar mass function from the literature, we calculate that in a volume limited, local Universe sample, clusters are most likely to be found around fairly massive galaxies (M$_* \sim 10^{10.8}$ M$_\odot$) and present a fitting function for the volume number density of clusters as a function of parent galaxy stellar mass. We find no correlation between T$_{\rm N}$ and large-scale environment, but do find a tendency for galaxies of fixed M$_*$ to have larger T$_{\rm N}$ if they have converted a larger proportion of their baryons into stars.

### Gravitational contraction versus Supernova driving and the origin of the velocity dispersion-size relation in molecular clouds

Molecular cloud observations show that clouds have non-thermal velocity dispersions that scale with the cloud size as $\sigma\propto R^{1/2}$ at constant surface density, and for varying surface density scale with both the clouds size and surface density, $\sigma^2 \propto R \Sigma$. The energy source driving these chaotic motions remains poorly understood. We describe the velocity dispersions observed in a cloud population formed in a kiloparsec-scale numerical simulation of a magnetized, supernova-driven, self-gravitating, interstellar medium, including diffuse heating and radiative cooling. We compare the relationships between velocity dispersion, size, and surface density measured in the simulated cloud population to those found in observations of Galactic molecular clouds. We find that external supernova explosions can not drive turbulent motions of the observed magnitudes within dense clouds. On the other hand, self-gravity also induces non-thermal motions as gravitationally bound clouds begin to collapse in our model, and by doing so their internal velocity dispersions recover the observed relations. Energy conservation suggests that the observed behavior is consistent with the kinetic energy being proportional to the gravitational energy. However, the clouds in our model show no sign of reaching a stable equilibrium state at any time, even for strongly magnetized clouds. We conclude that gravitationally bound molecular clouds are always in a state of gravitational collapse and their properties are a natural result of this chaotic collapse. In order to agree with observed star formation efficiencies, this process must be terminated by the early destruction of the clouds, presumably from internal stellar feedback.

### Lyman-\alpha{} Emitters in the context of hierarchical galaxy formation: predictions for VLT/MUSE surveys

The VLT Multi Unit Spectroscopic Explorer (MUSE) integral-field spectrograph can detect Ly\alpha{} emitters (LAE) in the redshift range $2.8 \lesssim z \lesssim 6.7$ in a homogeneous way. Ongoing MUSE surveys will notably probe faint Ly\alpha{} sources that are usually missed by current narrow-band surveys. We provide quantitative predictions for a typical wedding-cake observing strategy with MUSE based on mock catalogs generated with a semi-analytic model of galaxy formation coupled to numerical Ly\alpha{} radiation transfer models in gas outflows. We expect $\approx$ 1500 bright LAEs ($F_{Ly\alpha}$ $\gtrsim$ $10^{-17}$ erg s$^{-1}$ cm$^{-2}$) in a typical Shallow Field (SF) survey carried over $\approx$ 100 arcmin$^2$, and $\approx$ 2,000 sources as faint as $10^{-18}$ erg s$^{-1}$ cm$^{-2}$ in a Medium-Deep Field (MDF) survey over 10 arcmin$^2$. In a typical Deep Field (DF) survey of 1 arcmin$^2$, we predict that $\approx$ 500 extremely faint LAEs ($F_{Ly\alpha}$ $\gtrsim$ $4 \times 10^{-19}$ erg s$^{-1}$ cm$^{-2}$) will be found. Our results suggest that faint Ly\alpha{} sources contribute significantly to the cosmic Ly\alpha{} luminosity and SFR budget. While the host halos of bright LAEs at z $\approx$ 3 and 6 have descendants with median masses of $2 \times 10^{12}$ and $5 \times 10^{13}$ $M_{\odot}$ respectively, the faintest sources detectable by MUSE at these redshifts are predicted to reside in halos which evolve into typical sub-$L^{*}$ and $L^{*}$ galaxy halos at z = 0. We expect typical DF and MDF surveys to uncover the building blocks of Milky Way-like objects, even probing the bulk of the stellar mass content of LAEs located in their progenitor halos at z $\approx$ 3.

### Standing Shock Instability in Advection-Dominated Accretion Flows

Depending on the values of the energy and angular momentum per unit mass in the gas supplied at large radii, inviscid advection-dominated accretion flows can display velocity profiles with either pre-shock deceleration or pre-shock acceleration. Nakayama has shown that these two types of flow configurations are expected to have different stability properties. By employing the Chevalier & Imamura linearization method and the Nakayama instability boundary conditions, we discover that there are regions of parameters space where disk/shocks with outflows can be stable or unstable. In region of instability, we find that pre-shock deceleration is always unstable to the zeroth mode with zero frequency of oscillation, but is always stable to the fundamental and overtones. Furthermore, we also find that pre-shock acceleration is always unstable to the zeroth mode, and that the fundamental and overtones become increasingly less stable as the shock location moves away from the horizon when the disk half-height expands above $\sim 12$ gravitational radii at the shock radius. In region of stability, we demonstrate the zeroth mode to be stable for the velocity profiles that exhibit pre-shock acceleration and deceleration. Moreover, for models that are linearly unstable, our model suggests the possible existence of QPOs with ratios 2:3 and 3:5. These ratios are believed to occur in stellar and supermassive black hole candidates, for example in GRS 1915+105 and Sgr A*, respectively. We expect similar QPO ratios also exist in region of stable shocks.

### Spectroscopy of Luminous Compact Blue Galaxies in Distant Clusters II. Physical Properties of dE Progenitor Candidates

Luminous Compact Blue Galaxies (LCBGs) are an extreme star-bursting population of galaxies that were far more common at earlier epochs than today. Based on spectroscopic and photometric measurements of LCBGs in massive (M >10^15 M_sun), intermediate redshift (0.5 < z < 0.9) galaxy clusters, we present their rest-frame properties including star-formation rate, dynamical mass, size, luminosity, and metallicity. The appearance of these small, compact galaxies in clusters at intermediate redshift helps explain the observed redshift evolution in the size-luminosity relationship among cluster galaxies. In addition, we find the rest-frame properties of LCBGs appearing in galaxy clusters are indistinguishable from field LCBGs at the same redshift. Up to 35% of the LCBGs show significant discrepancies between optical and infrared indicators of star formation, suggesting that star formation occurs in obscured regions. Nonetheless, the star formation for LCBGs shows a decrease toward the center of the galaxy clusters. Based on their position and velocity, we estimate that up to 10% of cluster LCBGs are likely to merge with another cluster galaxy. Finally, the observed properties and distributions of the LCBGs in these clusters lead us to conclude that we are witnessing the quenching of the progenitors of dwarf elliptical galaxies that dominate the number density of present-epoch galaxy clusters.

### Tracing differential reddening with Diffuse Interstellar Bands. The globular cluster M 4 as a testbed

Diffuse interstellar bands (DIBs) are weak absorption features of interstellar origin present in the optical and infrared spectra of stars. Their use as a tool to trace the structure of the Galactic ISM is gaining relevance in the recent years. Here we present an experiment to test our ability to trace differential reddening on the plane of the sky by using the information relative to the DIB at $\lambda$6614 extracted from the spectra of cool stars. For that we made use of archive FLAMES data of the globular cluster M4, as well as WISE and Planck images for reference. We found a global positive trend between the distribution of the strength of the DIB, as traced by its equivalent width, and the amount of Galactic reddening, as traced by Planck. This result supports the use of DIBs to trace the small scale structure of the Galactic ISM.

### A Formation Scenario for the Disk of Satellites: Accretion of Satellites during Mergers

The Disk of Satellites (DoS) observed in the Andromeda galaxy is a thin and extended group of satellites, nearly perpendicular to the disk plane, that share a common direction of rotation about the centre of Andromeda. Although a DoS is also observed in the Milky Way galaxy, the prevalance of such structures in more distant galaxies remains controversial. Explanations for the formation of such DoSs vary widely from filamentary infall, or flattening due to the potential field from large scale structure, to galaxy interactions in a Mondian paradigm. Here we present an alternative scenario -- during a merger, a galaxy may bring its own satellite population when merging with another galaxy. We demonstrate how, under the correct circumstances, during the coalescence of the two galaxies, the satellite population can be spread into an extended, flattened structure, with a common direction of rotation about the merger remnant. We investigate the key parameters of the interaction, and the satellite population, that are required to form a DoS in this scenario.

### Revisiting the role of the Thermally-Pulsating Asymptotic Giant Branch phase in high-redshift galaxies

We study the debated contribution from thermally pulsing asymptotic giant branch (TP-AGB) stars in evolutionary population synthesis models. We investigate the Spectral Energy Distributions (SEDs) of a sample of 51 spectroscopically confirmed, high-z ($1.3<z_{\rm spec}<2.7$), galaxies using three evolutionary population synthesis models with strong, mild and light TP-AGB. Our sample is the largest of spectroscopically confirmed galaxies on which such models are tested so far. Galaxies were selected as passive, but we model them using a variety of star formation histories in order not to be dependent on this pre-selection. We find that the observed SEDs are best fitted with a significant contribution of TP-AGB stars or with substantial dust attenuation. Without including reddening, TP-AGB-strong models perform better and deliver solutions consistent within $1\sigma$ from the best-fit ones in the vast majority of cases. Including reddening, all models perform similarly. Using independent constraints from observations in the mid- and far-IR, we show that low/negligible dust attenuation, i.e. $E(B-V)\lesssim 0.05$ , should be preferred for the SEDs of passively-selected galaxies. Given that TP-AGB-light models give systematically older ages for passive galaxies, we suggest number counts of passive galaxies at higher redshifts as a further test to discriminate among stellar population models.

### Establishing the level of cylindrical rotation in Boxy/Peanut bulges

We present SAURON integral-field observations of a sample of 12 mid to high-inclination disk galaxies, to unveil hidden bars on the basis of their kinematics, i.e., the correlation between velocity and h3 profiles, and to establish their degree of cylindrical rotation. For the latter, we introduce a method to quantify cylindrical rotation that is robust against inner disk components. We confirm high-levels of cylindrical rotation in boxy/peanut bulges, but also observe this feature in a few galaxies with rounder bulges. We suggest that these are also barred galaxies with end-on orientations. Re-analysing published data for our own Galaxy using this new method, we determine that the Milky Way bulge is cylindrically rotating at the same level as the strongest barred galaxy in our sample. Finally, we use self-consistent three-dimensional N-body simulations of bar-unstable disks to study the dependence of cylindrical rotation on the bar's orientation and host galaxy inclination.

### Mapping dark matter in the Milky Way, a synopsis [Cross-Listing]

Mapping the dark matter distribution across our Galaxy represents a central challenge for the near future as a new generation of space-borne and ground-based astronomical surveys swiftly comes online. Here we present a synopsis of the present status of the field, reviewing briefly the baryonic content and the kinematics of the Milky Way and outlining the methods used to infer the dark matter component. The discussion then proceeds with some of the latest developments based on our own work. In particular, we present a new compilation of kinematic measurements tracing the rotation curve of the Galaxy and an exhaustive array of observation-based baryonic models setting the contribution of stellar bulge, stellar disc and gas to the total gravitational potential. The discrepancy between these two components is then quantified to derive the latest constraints on the dark matter distribution and on modified Newtonian dynamics. We shall end with an overview of future directions to improve our mapping of the dark matter distribution in the Milky Way.

### Mapping dark matter in the Milky Way, a synopsis [Cross-Listing]

Mapping the dark matter distribution across our Galaxy represents a central challenge for the near future as a new generation of space-borne and ground-based astronomical surveys swiftly comes online. Here we present a synopsis of the present status of the field, reviewing briefly the baryonic content and the kinematics of the Milky Way and outlining the methods used to infer the dark matter component. The discussion then proceeds with some of the latest developments based on our own work. In particular, we present a new compilation of kinematic measurements tracing the rotation curve of the Galaxy and an exhaustive array of observation-based baryonic models setting the contribution of stellar bulge, stellar disc and gas to the total gravitational potential. The discrepancy between these two components is then quantified to derive the latest constraints on the dark matter distribution and on modified Newtonian dynamics. We shall end with an overview of future directions to improve our mapping of the dark matter distribution in the Milky Way.

### Mapping dark matter in the Milky Way, a synopsis

Mapping the dark matter distribution across our Galaxy represents a central challenge for the near future as a new generation of space-borne and ground-based astronomical surveys swiftly comes online. Here we present a synopsis of the present status of the field, reviewing briefly the baryonic content and the kinematics of the Milky Way and outlining the methods used to infer the dark matter component. The discussion then proceeds with some of the latest developments based on our own work. In particular, we present a new compilation of kinematic measurements tracing the rotation curve of the Galaxy and an exhaustive array of observation-based baryonic models setting the contribution of stellar bulge, stellar disc and gas to the total gravitational potential. The discrepancy between these two components is then quantified to derive the latest constraints on the dark matter distribution and on modified Newtonian dynamics. We shall end with an overview of future directions to improve our mapping of the dark matter distribution in the Milky Way.

### The Imprints Of Galactic Environment On Cluster Formation and Evolution

Young star clusters (YSCs) appear to be a ubiquitous product of star formation in local galaxies, thus, they can be used to study the star formation process at work in their host galaxies. Moreover, YSCs are intrinsically brighter that single stars, potentially becoming the most important tracers of the recent star formation history in galaxies in the local Universe. In local galaxies, we also witness the presence of a large population of evolved star clusters, commonly called globular clusters (GCs). GCs peak formation history is very close to the redshift (z~2) when the cosmic star formation history reached the maximum. Therefore, GCs are usually associated to extreme star formation episodes in high-redshift galaxies. It is yet not clear whether YSCs and GCs share a similar formation process (same physics under different interstellar medium conditions) and evolution process, and whether the former can be used as progenitor analogs of the latter. In this invited contribution, I review general properties of YSC populations in local galaxies. I will summarise some of the current open questions in the field, with particular emphasis to whether or not galactic environments, where YSCs form, leave imprints on the nested populations. The importance of this rapidly developing field can be crucial in understanding GC formation and possibly the galactic environment condition where this ancient population formed.

### On the relation of optical obscuration and X-ray absorption in Seyfert galaxies

The optical classification of a Seyfert galaxy and whether it is considered X-ray absorbed are often used interchangeably. But there are many borderline cases and also numerous examples where the optical and X-ray classifications appear to be in conflict. In this article we re-visit the relation between optical obscuration and X-ray absorption in AGNs. We make use of our "dust color" method (Burtscher et al. 2015) to derive the optical obscuration A_V and consistently estimated X-ray absorbing columns using 0.3--150 keV spectral energy distributions. We also take into account the variable nature of the neutral gas column N_H and derive the Seyfert sub-classes of all our objects in a consistent way. We show in a sample of 25 local, hard-X-ray detected Seyfert galaxies (log L_X / (erg/s) ~ 41.5 - 43.5) that there can actually be a good agreement between optical and X-ray classification. If Seyfert types 1.8 and 1.9 are considered unobscured, the threshold between X-ray unabsorbed and absorbed should be chosen at a column N_H = 10^22.3 / cm^2 to be consistent with the optical classification. We find that N_H is related to A_V and that the N_H/A_V ratio is approximately Galactic or higher in all sources, as indicated previously. But in several objects we also see that deviations from the Galactic ratio are only due to a variable X-ray column, showing that (1) deviations from the Galactic N_H/A_V can simply be explained by dust-free neutral gas within the broad line region in some sources, that (2) the dust properties in AGNs can be similar to Galactic dust and that (3) the dust color method is a robust way to estimate the optical extinction towards the sublimation radius in all but the most obscured AGNs.

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