## Recent Postings from Cosmology and Nongalactic

### Prospects for Cosmological Collider Physics

It is generally expected that heavy fields are present during inflation, which can leave their imprint in late-time cosmological observables. The main signature of these fields is a small amount of distinctly shaped non-Gaussianity, which if detected, would provide a wealth of information about the particle spectrum of the inflationary Universe. Here we investigate to what extent these signatures can be detected or constrained using futuristic 21-cm surveys. We construct model-independent templates that extract the squeezed-limit behavior of the bispectrum, and examine their overlap with standard inflationary shapes and secondary non-Gaussianities. We then use these templates to forecast detection thresholds for different masses and couplings using a 3D reconstruction of modes during the dark ages ($z\sim 30-100$). We consider interactions of several broad classes of models and quantify their detectability as a function of the baseline of a dark ages interferometer. Our analysis shows that there exists the tantalizing possibility of discovering new particles with different masses and interactions with future 21-cm surveys.

### Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves [Cross-Listing]

We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

### Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves

We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

### Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves [Cross-Listing]

We investigate the potential for the LISA space-based interferometer to detect the stochastic gravitational wave background produced from different mechanisms during inflation. Focusing on well-motivated scenarios, we study the resulting contributions from particle production during inflation, inflationary spectator fields with varying speed of sound, effective field theories of inflation with specific patterns of symmetry breaking and models leading to the formation of primordial black holes. The projected sensitivities of LISA are used in a model-independent way for various detector designs and configurations. We demonstrate that LISA is able to probe these well-motivated inflationary scenarios beyond the irreducible vacuum tensor modes expected from any inflationary background.

### Primordial Universe with radiation and Bose-Einstein condensate [Cross-Listing]

In this work we derive a scenario where the early Universe consists of radiation and the Bose-Einstein condensate. We have included in our analysis the possibility of gravitational self-interaction due to the Bose-Einstein condensate being attractive or repulsive. After presenting the general structure of our model, we proceed to compute the finite-norm wave packet solutions to the Wheeler-DeWitt equation. The behavior of the scale factor is studied by applying the many-worlds interpretation of quantum mechanics. At the quantum level the cosmological model, in both attractive and repulsive cases, is free from the Big Bang singularity.

### Primordial Universe with radiation and Bose-Einstein condensate

In this work we derive a scenario where the early Universe consists of radiation and the Bose-Einstein condensate. We have included in our analysis the possibility of gravitational self-interaction due to the Bose-Einstein condensate being attractive or repulsive. After presenting the general structure of our model, we proceed to compute the finite-norm wave packet solutions to the Wheeler-DeWitt equation. The behavior of the scale factor is studied by applying the many-worlds interpretation of quantum mechanics. At the quantum level the cosmological model, in both attractive and repulsive cases, is free from the Big Bang singularity.

### Photometric properties of intermediate redshift Type Ia Supernovae observed by SDSS-II Supernova Survey

We have analyzed multi-band light curves of 328 intermediate redshift (0.05 <= z < 0.24) type Ia supernovae (SNe Ia) observed by the Sloan Digital Sky Survey-II Supernova Survey (SDSS-II SN Survey). The multi-band light curves were parameterized by using the Multi-band Stretch Method, which can simply parameterize light curve shapes and peak brightness without dust extinction models. We found that most of the SNe Ia which appeared in red host galaxies (u - r > 2.5) don't have a broad light curve width and the SNe Ia which appeared in blue host galaxies (u - r < 2.0) have a variety of light curve widths. The Kolmogorov-Smirnov test shows that the colour distribution of SNe Ia appeared in red / blue host galaxies is different (significance level of 99.9%). We also investigate the extinction law of host galaxy dust. As a result, we find the value of Rv derived from SNe Ia with medium light curve width is consistent with the standard Galactic value. On the other hand, the value of Rv derived from SNe Ia that appeared in red host galaxies becomes significantly smaller. These results indicate that there may be two types of SNe Ia with different intrinsic colours, and they are obscured by host galaxy dust with two different properties.

### Scalar Dark Matter: Real vs Complex [Cross-Listing]

We update the parameter spaces for both a real and complex scalar dark matter via the Higgs portal. In the light of constraints arising from the LUX 2016 data, the latest Higgs invisible decay and the gamma ray spectrum, the dark matter mass region is further restricted to a narrow window between $54-62.2$ GeV in both cases, and it is excluded up to 660 GeV and 2800 GeV for the real and complex scalar, respectively.

### Scalar Dark Matter: Real vs Complex

We update the parameter spaces for both a real and complex scalar dark matter via the Higgs portal. In the light of constraints arising from the LUX 2016 data, the latest Higgs invisible decay and the gamma ray spectrum, the dark matter mass region is further restricted to a narrow window between $54-62.2$ GeV in both cases, and it is excluded up to 660 GeV and 2800 GeV for the real and complex scalar, respectively.

### Holographic Theory of Gravity and Cosmology

According to the holographic principle, the maximum amount of information stored in a region of space scales as the area of its two-dimensional surface, like a hologram. We show that the holographic principle can be understood heuristically as originated from quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant $\Lambda$ of the observed magnitude, in agreement with the result obtained for the present and recent cosmic eras, by using unimodular gravity and causal-set theory. By generalizing the concept of entropic gravity, we find a critical acceleration parameter related to $\Lambda$ in galactic dynamics, and we construct a phenomenological model of dark matter which we call "modified dark matter" (MDM). We provide successful observational tests of MDM at both the galactic and cluster scales. We also discuss the possibility that the quanta of both dark energy and dark matter obey the quantum Boltzmann statistics or infinite statistics as described by a curious average of the bosonic and fermionic algebras.

### Holographic Theory of Gravity and Cosmology [Cross-Listing]

According to the holographic principle, the maximum amount of information stored in a region of space scales as the area of its two-dimensional surface, like a hologram. We show that the holographic principle can be understood heuristically as originated from quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant $\Lambda$ of the observed magnitude, in agreement with the result obtained for the present and recent cosmic eras, by using unimodular gravity and causal-set theory. By generalizing the concept of entropic gravity, we find a critical acceleration parameter related to $\Lambda$ in galactic dynamics, and we construct a phenomenological model of dark matter which we call "modified dark matter" (MDM). We provide successful observational tests of MDM at both the galactic and cluster scales. We also discuss the possibility that the quanta of both dark energy and dark matter obey the quantum Boltzmann statistics or infinite statistics as described by a curious average of the bosonic and fermionic algebras.

### Holographic Theory of Gravity and Cosmology [Cross-Listing]

According to the holographic principle, the maximum amount of information stored in a region of space scales as the area of its two-dimensional surface, like a hologram. We show that the holographic principle can be understood heuristically as originated from quantum fluctuations of spacetime. Applied to cosmology, this consideration leads to a dynamical cosmological constant $\Lambda$ of the observed magnitude, in agreement with the result obtained for the present and recent cosmic eras, by using unimodular gravity and causal-set theory. By generalizing the concept of entropic gravity, we find a critical acceleration parameter related to $\Lambda$ in galactic dynamics, and we construct a phenomenological model of dark matter which we call "modified dark matter" (MDM). We provide successful observational tests of MDM at both the galactic and cluster scales. We also discuss the possibility that the quanta of both dark energy and dark matter obey the quantum Boltzmann statistics or infinite statistics as described by a curious average of the bosonic and fermionic algebras.

### Density-dependent clustering: I. Pulling back the curtains on motions of the BAO peak

The most common statistic used to analyze large-scale structure surveys is the correlation function, or power spectrum. Here, we show how slicing' the correlation function on local density brings sensitivity to interesting non-Gaussian features in the large-scale structure, such as the expansion or contraction of baryon acoustic oscillations (BAO) according to the local density. The sliced correlation function measures the large-scale flows that smear out the BAO, instead of just correcting them as reconstruction algorithms do. Thus, we expect the sliced correlation function to be useful in constraining the growth factor, and modified gravity theories that involve the local density. We find that the full run of the BAO peak location with density is best revealed when slicing on a $\sim$40 Mpc/$h$ filtered density. But slicing on a $\sim100$ Mpc/$h$ filtered density may be most useful in distinguishing between underdense and overdense regions, whose BAO peaks are shifted by a substantial $\sim$5 Mpc/$h$ at $z=0$. We also introduce curtain plots' showing how local densities drive particle motions toward or away from each other over the course of an $N$-body simulation.

### Initial conditions for inflation [Cross-Listing]

A novel proposal is presented, which manages to overcome the initial conditions problem of inflation with a plateau. An earlier period of proto-inflation, beginning at Planck scale, accounts for the Universe expansion and arranges the required initial conditions for inflation on the plateu to commence. We show that, if proto-inflation is power-law, it does not suffer from any eternal inflationary stage. A simple model realisation is constructed in the context of $\alpha$-attractors, which can both generate the inflationary plateau and the exponential slopes around it, necessary for the two inflation stages. Our mechanism allows to assume chaotic initial conditions at the Planck scale for proto-inflation, it is generic and it is shown to work without fine-tunings.

### Initial conditions for inflation

A novel proposal is presented, which manages to overcome the initial conditions problem of inflation with a plateau. An earlier period of proto-inflation, beginning at Planck scale, accounts for the Universe expansion and arranges the required initial conditions for inflation on the plateu to commence. We show that, if proto-inflation is power-law, it does not suffer from any eternal inflationary stage. A simple model realisation is constructed in the context of $\alpha$-attractors, which can both generate the inflationary plateau and the exponential slopes around it, necessary for the two inflation stages. Our mechanism allows to assume chaotic initial conditions at the Planck scale for proto-inflation, it is generic and it is shown to work without fine-tunings.

### Initial conditions for inflation [Cross-Listing]

A novel proposal is presented, which manages to overcome the initial conditions problem of inflation with a plateau. An earlier period of proto-inflation, beginning at Planck scale, accounts for the Universe expansion and arranges the required initial conditions for inflation on the plateu to commence. We show that, if proto-inflation is power-law, it does not suffer from any eternal inflationary stage. A simple model realisation is constructed in the context of $\alpha$-attractors, which can both generate the inflationary plateau and the exponential slopes around it, necessary for the two inflation stages. Our mechanism allows to assume chaotic initial conditions at the Planck scale for proto-inflation, it is generic and it is shown to work without fine-tunings.

### On the linearity of tracer bias around voids

The large-scale structure of the universe can only be observed directly via luminous tracers of the underlying distribution of dark matter. However, the clustering statistics of tracers are biased and depend on various properties of the tracers themselves, such as their host-halo mass and formation and assembly history. On very large scales, where density fluctuations are within the linear regime, this tracer bias results in a constant offset in the clustering amplitude, which is known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centered on cosmic voids, depressions of the density field that spatially dominate the universe. We consider three different types of tracers: galaxies, galaxy clusters and AGNs, extracted from the hydrodynamical simulation suite Magneticum Pathfinder. In contrast to common clustering statistics that focus on the auto-correlation of tracers, we find that void-tracer cross-correlations are successfully described by a linear bias-relation within voids. The tracer-density profile of voids can thus be related to their matter-density profile by a single number. We show that this number coincides with the linear tracer bias extracted from the large-scale auto-correlation function and expectations from theory, if sufficiently large voids are considered. For smaller voids we observe a shift towards higher values. This has important consequences on cosmological parameter inference from large-scale structure, as the problem of unknown tracer bias is alleviated up to a constant number. The smallest scales in existing datasets become accessible to simpler models, providing modes of the density field that have been disregarded so far, but may help to further reduce statistical errors and to constrain cosmology on smaller scales.

### Impact of Instrument Responses on the Detectability of One-point Statistics from Redshifted 21 cm Observations

We study the impact of instrumental systematics on the variance, skewness, and kurtosis of redshifted 21 cm intensity fluctuation observations from the Epoch of Reionization. We simulate realistic 21 cm observations based on the Murchison Widefield Array (MWA) Phase I reionization experiment, using the array's point spread function (PSF) and antenna beam patterns, full-sky 21 cm models, and the FHD imaging pipeline. We measure the observed redshift evolution of pixel probability density functions (PDF) and one-point statistics from the simulated maps, comparing them to the measurements derived from simpler simulations that represent the instrument PSFs with Gaussian kernels. We find that both methods yield statistics with similar trends with greater than 80% correlation. We perform additional simulations based on the Hydrogen Epoch of Reionization Array (HERA), using Gaussian kernels as the instrument PSFs, and study the effect of frequency binning on the statistics. We find that PSF smoothing and sampling variance from measuring the statistics over limited field of view dilute intrinsic features and add fluctuations to the statistics but reveal new detectable features. Observed kurtosis will increase when a few extremely high or low temperature regions are present in the maps. Frequency binning reduces the thermal uncertainty but can also blur regions along the frequency dimension, resulting in kurtosis peaks that only appear in statistics derived from maps of certain frequency bins. We further find that the kurtosis peaks will reach their maxima when the angular resolution of the PSFs match the size scale of the extreme regions that produce the peaks. The HERA array should be capable of charting the evolution of the observed skewness and kurtosis of the 21 cm fluctuations with high sensitivity while the MWA Phase I will likely be capable of detecting the peak in variance.

### Zooming into the Cosmic Horseshoe: new insights on the lens profile and the source shape

The gravitational lens SDSS J1148+1930, also known as the Cosmic Horseshoe, is one of the biggest and of the most detailed Einstein rings ever observed. We use the forward reconstruction method implemented in the lens fitting code Lensed to investigate with great detail the properties of the lens and of the background source. We model the lens with different mass distributions, focusing in particular on the determination of the slope of the dark matter component. The inherent degeneracy between the lens slope and the source size can be broken when we can isolate separate components of each lensed image, as in this case. For an elliptical power law model, $\kappa(r) \sim r^{-t}$, the results favour a flatter-than-isothermal slope with a maximum-likelihood value t = 0.08. Instead, when we consider the contribution of the baryonic matter separately, the maximum-likelihood value of the slope of the dark matter component is t = 0.31 or t = 0.44, depending on the assumed Initial Mass Function. We discuss the origin of this result by analysing in detail how the images and the sources change when the slope t changes. We also demonstrate that these slope values at the Einstein radius are not inconsistent with recent forecast from the theory of structure formation in the LambdaCDM model.

### Dipolar modulation in the size of galaxies: The effect of Doppler magnification

Objects falling into an overdensity appear larger on its near side and smaller on its far side than other objects at the same redshift. This produces a dipolar pattern of magnification, primarily as a consequence of the Doppler effect. At low redshift this Doppler magnification completely dominates the usual integrated gravitational lensing contribution to the lensing magnification. We show that one can optimally observe this pattern by extracting the dipole in the cross-correlation of number counts and galaxy sizes. This dipole allows us to almost completely remove the contribution from gravitational lensing up to redshift 0.5, and even at high redshift z~1 the dipole picks up the Doppler magnification predominantly. Doppler magnification should be easily detectable in current and upcoming optical and radio surveys; by forecasting for telescopes such as the SKA, we show that this technique is competitive with using peculiar velocities via redshift-space distortions to constrain dark energy. It produces similar yet complementary constraints on the cosmological model to those found using measurements of the cosmic shear.

### Two fundamental cosmological laws of the Local Universe

The Local Universe is the most detail studied part of the observable region of space with the radius R about 100 Mpc. There are two empirical fundamental cosmological laws directly established from observations in the Local Universe independently from cosmological theory: first, the Hubble-Humason-Sandage linear redshift-distance law and second, Carpenter- Karachentsev-deVaucouleurs density-radius power-law. Review of modern state of these empirical laws and their cosmological significance is given. Possible theoretical interpretations of the surprising coexistence of both laws at the spatial scales from 1 Mpc to 100 Mpc are discussed. Comparison of the standard space-expansion explanation of the cosmological redshift with possible global gravitational redshift model is given

### Architecture of the Andromeda: a quantitative analysis of clustering in the inner stellar halo

We present a quantitative measurement of the amount of clustering present in the inner $\sim30$ kpc of the stellar halo of the Andromeda galaxy (M31). For this we analyse the angular positions and radial velocities of the carefully selected Planetary Nebulae (PNe) in the M31 stellar halo. We study the cumulative distribution of pair-wise distances in angular position and line of sight velocity space, and find that the M31 stellar halo contains substantially more stars in the form of close pairs as compared to that of a featureless smooth halo. In comparison to a smoothed/scrambled distribution we estimate that the clustering excess in the M31 inner halo is roughly $40\%$ at maximum and on average $\sim 20\%$. Importantly, comparing against the 11 stellar halo models of \cite{2005ApJ...635..931B}, which were simulated within the context of the $\Lambda{\rm CDM}$ cosmological paradigm, we find that the amount of substructures in the M31 stellar halo closely resembles that of a typical $\Lambda{\rm CDM}$ halo.

### The Main Sequences of Starforming Galaxies and Active Galactic Nuclei at High Redshift

We provide a novel, unifying physical interpretation on the origin, the average shape, the scatter, and the cosmic evolution for the main sequences of starforming galaxies and active galactic nuclei at high redshift z $\gtrsim$ 1. We achieve this goal in a model-independent way by exploiting: (i) the redshift-dependent SFR functions based on the latest UV/far-IR data from HST/Herschel, and re- lated statistics of strong gravitationally lensed sources; (ii) deterministic evolutionary tracks for the history of star formation and black hole accretion, gauged on a wealth of multiwavelength observations including the observed Eddington ratio distribution. We further validate these ingredients by showing their consistency with the observed galaxy stellar mass functions and AGN bolometric luminosity functions at different redshifts via the continuity equation approach. Our analysis of the main sequence for high-redshift galaxies and AGNs highlights that the present data are consistently interpreted in terms of an in situ coevolution scenario for star formation and black hole accretion, envisaging these as local, time coordinated processes.

### Meaning of prescriptions I and II in Higgs inflation [Cross-Listing]

We consider the prescription dependence of the Higgs effective potential under the presence of general non-minimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure takes simple form either in the Jordan or Einstein frame. The resultant effective action becomes identical in both cases when we properly take into account the quartically divergent term coming from the change of measure. Working in the counter-term formalism, we clarify that the difference between the prescriptions I and II comes from the counter term to cancel the logarithmic divergence. This difference can be absorbed into the choice of tree-level potential from the infinitely many possibilities, including all the higher-dimensional terms. We also present another mechanism to obtain a flat potential by freezing the running of the effective quartic coupling for large field values, using the non-minimal coupling in the gauge kinetic function.

### Meaning of prescriptions I and II in Higgs inflation

We consider the prescription dependence of the Higgs effective potential under the presence of general non-minimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure takes simple form either in the Jordan or Einstein frame. The resultant effective action becomes identical in both cases when we properly take into account the quartically divergent term coming from the change of measure. Working in the counter-term formalism, we clarify that the difference between the prescriptions I and II comes from the counter term to cancel the logarithmic divergence. This difference can be absorbed into the choice of tree-level potential from the infinitely many possibilities, including all the higher-dimensional terms. We also present another mechanism to obtain a flat potential by freezing the running of the effective quartic coupling for large field values, using the non-minimal coupling in the gauge kinetic function.

### Meaning of prescriptions I and II in Higgs inflation [Cross-Listing]

We consider the prescription dependence of the Higgs effective potential under the presence of general non-minimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure takes simple form either in the Jordan or Einstein frame. The resultant effective action becomes identical in both cases when we properly take into account the quartically divergent term coming from the change of measure. Working in the counter-term formalism, we clarify that the difference between the prescriptions I and II comes from the counter term to cancel the logarithmic divergence. This difference can be absorbed into the choice of tree-level potential from the infinitely many possibilities, including all the higher-dimensional terms. We also present another mechanism to obtain a flat potential by freezing the running of the effective quartic coupling for large field values, using the non-minimal coupling in the gauge kinetic function.

### Meaning of prescriptions I and II in Higgs inflation [Cross-Listing]

We consider the prescription dependence of the Higgs effective potential under the presence of general non-minimal couplings. We evaluate the fermion loop correction to the effective action in a simplified Higgs-Yukawa model whose path integral measure takes simple form either in the Jordan or Einstein frame. The resultant effective action becomes identical in both cases when we properly take into account the quartically divergent term coming from the change of measure. Working in the counter-term formalism, we clarify that the difference between the prescriptions I and II comes from the counter term to cancel the logarithmic divergence. This difference can be absorbed into the choice of tree-level potential from the infinitely many possibilities, including all the higher-dimensional terms. We also present another mechanism to obtain a flat potential by freezing the running of the effective quartic coupling for large field values, using the non-minimal coupling in the gauge kinetic function.

### Cosmological Implications of Trace-Charged Dark Matter

Trace charge imbalances can explain puzzling cosmological observations such as the large missing' fraction of electrons in cosmic rays and their contrast to the charge-neutral solar wind, the extreme energy sources that sustain quasars, galactic jets, and active galactic nuclei, the origin and nature of dark matter' galaxy haloes, and the apparent acceleration of the expansion of the Universe, obviating $\Lambda$CDM. When there are $\sim \num{9e-19}$ amounts of excess $\ce{H3+}$ or $\ce{H-}$ within cold diffuse clouds of $\ce{H2}$, residual repulsive Coulomb forces are comparable to the gravitational attractions between hadrons. This trace-charged dark matter is inert with respect to static electrogravitional self-attractions, but still responds to electromagnetic fields and gravitational attractions with uncharged matter. Residual trace charge is also the ionic catalyst that keeps dark matter in the state of unseen clouds of cold molecular hydrogen plus trace $\ce{H3+}$. Once warm enough to partially ionize, bright matter preferentially expels its net charge to become nearly charge-neutral with respect to surrounding trace-charged dark matter. Planets surrounding stars become charge neutral as they bathe in a charge-neutral stellar wind. In contrast, at AGNs, newly ionized protons along with a significant fraction of entrained dark matter are Coulomb-expelled to relativistic velocities in polar jets that initiate near the event horizon of a trace-charged supermassive black hole. Extrasolar cosmic rays generated by these and from similar speed jets from accreting charged black holes would be strongly proton-dominated, as observed. The original trace charge imbalances could have originated during the Big Bang.

### Spontaneous Baryogenesis without Baryon Isocurvature

We propose a new class of spontaneous baryogenesis models that does not produce baryon isocurvature perturbations. The baryon chemical potential in these models is independent of the field value of the baryon-generating scalar, hence the scalar field fluctuations are blocked from propagating into the baryon isocurvature. We demonstrate this mechanism in simple examples where spontaneous baryogenesis is driven by a non-canonical scalar field. The suppression of the baryon isocurvature allows spontaneous baryogenesis to be compatible even with high-scale inflation.

### Spontaneous Baryogenesis without Baryon Isocurvature [Cross-Listing]

We propose a new class of spontaneous baryogenesis models that does not produce baryon isocurvature perturbations. The baryon chemical potential in these models is independent of the field value of the baryon-generating scalar, hence the scalar field fluctuations are blocked from propagating into the baryon isocurvature. We demonstrate this mechanism in simple examples where spontaneous baryogenesis is driven by a non-canonical scalar field. The suppression of the baryon isocurvature allows spontaneous baryogenesis to be compatible even with high-scale inflation.

### Spontaneous Baryogenesis without Baryon Isocurvature [Cross-Listing]

We propose a new class of spontaneous baryogenesis models that does not produce baryon isocurvature perturbations. The baryon chemical potential in these models is independent of the field value of the baryon-generating scalar, hence the scalar field fluctuations are blocked from propagating into the baryon isocurvature. We demonstrate this mechanism in simple examples where spontaneous baryogenesis is driven by a non-canonical scalar field. The suppression of the baryon isocurvature allows spontaneous baryogenesis to be compatible even with high-scale inflation.

### What is the right way to quench star formation in semi-analytic model of galaxy formation?

Semi-analytic models of galaxy formation are powerful tools to study the evolution of galaxy population in a cosmological context. However, most models over-predict the number of low-mass galaxies at high redshifts and the color of model galaxies are not right in the sense that low-mass satellite galaxies are too red and centrals are too blue. The recent version of the L-Galaxies model by Henriques et al.(H15) is a step forward to solve these problems by reproducing the evolution of stellar mass function and the overall fraction of red galaxies. In this paper we compare the two model predictions of L-Galaxies (the other is Guo et al. , G13) to the SDSS data in detail. We find that in the H15 model the red fraction of central galaxies now agrees with the data due to their implementation of strong AGN feedback, but the stellar mass of centrals in massive haloes is now slightly lower than the data. For satellite galaxies, the red fraction of low-mass galaxies ($\log M_{*}/M_{\odot} < 10$) also agrees with the data, but the color of massive satellites ($10 < \log M_{*}/M_{\odot} < 11$) is slightly bluer. The correct color of centrals and bluer color of massive satellites indicate that the quenching in massive satellites are not strong enough. We also find that there are too much red spirals and less bulge-dominated galaxies in both H15 and G13 models. Our results suggest that additional mechanisms, such as more minor merger or disk instability, are needed to slightly increase the stellar mass of central galaxy in massive galaxies, mainly in the bulge component, and the bulge dominated galaxy will be quenched or then be quenched by any other mechanisms.

### Low-$\ell$ power suppression in punctuated inflation

Motivated by Planck confirmation of an anomalously low value of the CMB temperature fluctuations up to multipole $\ell<40$, we in this paper try to explain such feature by investigating case of punctuated inflation scenario. This form of inflation potential is inspired by MSSM wherein suppression of curvature perturbation power at large scales is produced by introducing period of fast-roll phase of the inflation sandwiched between two stages of slow-roll phase. We apply Markov Chain Monte Carlo analysis to determine posterior distribution and the best fit values of the model parameters using recent WMAP9 and Planck data. We show that WMAP9 and Planck results are consistent with each other. We shown that the Planck data gives much tighter constraints for punctuated inflation parameters. We find that punctuated inflation leads to better fit in CMB data compared to simple power law model. For WMAP9 data the improvement in fit is marginal ($\Delta \chi^2\sim 4$), however, for WMAP9+Planck the improvement is significant ($\Delta \chi^2\sim 17$). We find that $AIC$ does not discriminate between punctuated inflation and simple power law model for WMAP9 data. However, for WMAP9+Planck data we find that punctuated inflation is strongly favored over a simple power law spectrum.

### Baryon Acoustic Oscillations reconstruction with pixels

Gravitational non-linear evolution induces a shift in the position of the baryon acoustic oscillations (BAO) peak together with a damping and broadening of its shape that bias and degrades the accuracy with which the position of the peak can be determined. BAO reconstruction is a technique developed to undo part of the effect of non-linearities. We present a new reconstruction method that consists in displacing pixels instead of galaxies and whose implementation is easier than the standard reconstruction method. We show that our method is equivalent to the standard reconstruction technique in the limit where the number of pixels becomes very large. This method is particularly useful in surveys where individual galaxies are not resolved, as in 21cm intensity mapping observations. We validate our method by reconstructing mock pixelated maps, that we build from the distribution of matter and halos in real- and redshift-space, from a large set of numerical simulations. We find that our method is able to decrease the uncertainty in the BAO peak position by 30-50% over the typical angular resolution scales of 21 cm intensity mapping experiments.

### Heavy right-handed neutrino dark matter in left-right models [Cross-Listing]

We show that in a class of non-supersymmetric left-right extensions of the Standard Model (SM), the lightest right-handed neutrino (RHN) can play the role of thermal Dark Matter (DM) in the Universe for a wide mass range from TeV to PeV. Our model is based on the gauge group $SU(3)_c \times SU(2)_L\times SU(2)_R\times U(1)_{Y_L}\times U(1)_{Y_R}$ in which a heavy copy of the SM fermions are introduced and the stability of the RHN DM is guaranteed by an automatic $Z_2$ symmetry present in the leptonic sector. In such models the active neutrino masses are obtained via the type-II seesaw mechanism. We find a lower bound on the RHN DM mass of order TeV from relic density constraints, as well as an unitarity upper bound in the multi-TeV to PeV scale, depending on the entropy dilution factor. The RHN DM could be made long-lived by soft-breaking of the $Z_2$ symmetry and provides a concrete example of decaying DM interpretation of the PeV neutrinos observed at IceCube.

### Heavy right-handed neutrino dark matter in left-right models

We show that in a class of non-supersymmetric left-right extensions of the Standard Model (SM), the lightest right-handed neutrino (RHN) can play the role of thermal Dark Matter (DM) in the Universe for a wide mass range from TeV to PeV. Our model is based on the gauge group $SU(3)_c \times SU(2)_L\times SU(2)_R\times U(1)_{Y_L}\times U(1)_{Y_R}$ in which a heavy copy of the SM fermions are introduced and the stability of the RHN DM is guaranteed by an automatic $Z_2$ symmetry present in the leptonic sector. In such models the active neutrino masses are obtained via the type-II seesaw mechanism. We find a lower bound on the RHN DM mass of order TeV from relic density constraints, as well as an unitarity upper bound in the multi-TeV to PeV scale, depending on the entropy dilution factor. The RHN DM could be made long-lived by soft-breaking of the $Z_2$ symmetry and provides a concrete example of decaying DM interpretation of the PeV neutrinos observed at IceCube.

### Gravitons that shake hands [Cross-Listing]

We examine some of the roots of parity violation for gravitons and uncover a closely related new effect: correlations between right and left handed gravitons. Such correlators have spin 4 if they involve gravitons moving along the same direction, and spin zero for gravitons moving with opposite directions. In the first case, the most immediate implication would be a degree of linear polarization for the tensor vacuum fluctuations, which could be seen by gravity wave detectors sensitive enough to probe the primordial background, its degree of polarization and anisotropies. Looking at the anisotropy of the gravity waves linear polarization we identify the parity respecting and violating components of the effect. The imprint on the CMB temperature and polarization would be more elusive, since it averages to zero in the two-point functions, appearing only in their cosmic variance or in fourth order correlators. In contrast, spin zero correlations would have an effect on the two point function of the CMB temperature and polarization, enhancing the $BB$ component if they were anti-correlations. Such correlations represent an amplitude for the production of standing waves, as first envisaged by Grishchuk, and could also leave an interesting signature for gravity wave detectors.

### Gravitons that shake hands

We examine some of the roots of parity violation for gravitons and uncover a closely related new effect: correlations between right and left handed gravitons. Such correlators have spin 4 if they involve gravitons moving along the same direction, and spin zero for gravitons moving with opposite directions. In the first case, the most immediate implication would be a degree of linear polarization for the tensor vacuum fluctuations, which could be seen by gravity wave detectors sensitive enough to probe the primordial background, its degree of polarization and anisotropies. Looking at the anisotropy of the gravity waves linear polarization we identify the parity respecting and violating components of the effect. The imprint on the CMB temperature and polarization would be more elusive, since it averages to zero in the two-point functions, appearing only in their cosmic variance or in fourth order correlators. In contrast, spin zero correlations would have an effect on the two point function of the CMB temperature and polarization, enhancing the $BB$ component if they were anti-correlations. Such correlations represent an amplitude for the production of standing waves, as first envisaged by Grishchuk, and could also leave an interesting signature for gravity wave detectors.

### Effects of active-sterile neutrino mixing during primordial nucleosynthesis

In the present work, we discuss the effects of the inclusion of sterile-active neutrino oscillations during the production of primordial light-nuclei. We assume that the sterile neutrino mass-eigenstate might oscillate with the two lightest active neutrino mass- eigenstates, with mixing angles ${\phi}_1$ and ${\phi}_2$. We also allow a constant renormalization (represented by a parameter (${\zeta}$)) of the sterile neutrino occupation factor. Taking ${\zeta}$ and the mixing angles as free parameters, we have computed distribution functions of active and sterile neutrinos and primordial abundances. Using observable data we set constrains in the free parameters of the model. It is found that the data on primordial abundances are consistent with small mixing angles and with a value of ${\zeta}$ smaller than 0.65 at 3${\sigma}$ level.

### Simulating the formation of massive seed black holes in the early Universe. III: The influence of X-rays

The direct collapse black hole (DCBH) model attempts to explain the observed number density of supermassive black holes in the early Universe by positing that they grew from seed black holes with masses of $10^{4}$-$10^{5} \: {\rm M_{\odot}}$ that formed by the quasi-isothermal collapse of gas in metal-free protogalaxies cooled by atomic hydrogen emission. For this model to work, H$_{2}$ formation must be suppressed in at least some of these systems by a strong extragalactic radiation field. The predicted number density of DCBH seeds is highly sensitive to the minimum value of the ultraviolet (UV) flux required to suppress H$_{2}$ formation, $J_{\rm crit}$. In this paper, we examine how the value of $J_{\rm crit}$ varies as we vary the strength of a hypothetical high-redshift X-ray background. We confirm earlier findings that when the X-ray flux $J_{\rm X}$ is large, the critical UV flux scales as $J_{\rm crit} \propto J_{\rm X}^{1/2}$. We also carefully explore possible sources of uncertainty arising from how the X-rays are modelled. We use a reaction-based reduction technique to analyze the chemistry of H$_{2}$ in the X-ray illuminated gas and identify a critical subset of 35 chemical reactions that must be included in our chemical model in order to predict $J_{\rm crit}$ accurately. We further show that $J_{\rm crit}$ is insensitive to the details of how secondary ionization or He$^{+}$ recombination are modelled, but does depend strongly on the assumptions made regarding the column density of the collapsing gas.

### Imprint of primordial inflation on the dark energy equation of state in non-local gravity

In cosmological models where dark energy has a dynamical origin one would expect that a primordial inflationary epoch leaves no imprint on the behavior of dark energy near the present epoch. We show that a notable exception to this behavior is provided by a nonlocal infrared modification of General Relativity, the so-called RT model. It has been previously shown that this model fits the cosmological data with an accuracy comparable to $\Lambda$CDM, with the same number of free parameters. Here we show that in this model the dark energy equation of state (EOS) near the present epoch is significantly affected by the existence of an epoch of primordial inflation. A smoking-gun signature of the model is a well-defined prediction for the dark energy EOS, $w_{\rm DE}(z)$, evolving with redshift from a non-phantom to a phantom behavior, with deviations from $-1$ already very close to the limits excluded by the Planck 2015 data. Future missions such as Euclid should be able to clearly confirm or disprove this prediction.

### Imprint of primordial inflation on the dark energy equation of state in non-local gravity [Cross-Listing]

In cosmological models where dark energy has a dynamical origin one would expect that a primordial inflationary epoch leaves no imprint on the behavior of dark energy near the present epoch. We show that a notable exception to this behavior is provided by a nonlocal infrared modification of General Relativity, the so-called RT model. It has been previously shown that this model fits the cosmological data with an accuracy comparable to $\Lambda$CDM, with the same number of free parameters. Here we show that in this model the dark energy equation of state (EOS) near the present epoch is significantly affected by the existence of an epoch of primordial inflation. A smoking-gun signature of the model is a well-defined prediction for the dark energy EOS, $w_{\rm DE}(z)$, evolving with redshift from a non-phantom to a phantom behavior, with deviations from $-1$ already very close to the limits excluded by the Planck 2015 data. Future missions such as Euclid should be able to clearly confirm or disprove this prediction.

### Special relativistic hydrodynamics with gravitation [Cross-Listing]

The special relativistic hydrodynamics with weak gravity is hitherto unknown in the literature. Whether such an asymmetric combination is possible was unclear. Here, the hydrodynamic equations with Poisson-type gravity considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit are consistently derived from Einstein's general relativity. Analysis is made in the maximal slicing where the Poisson's equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the {\it general} hypersurface condition. Our formulation includes the anisotropic stress.

### Special relativistic hydrodynamics with gravitation

The special relativistic hydrodynamics with weak gravity is hitherto unknown in the literature. Whether such an asymmetric combination is possible was unclear. Here, the hydrodynamic equations with Poisson-type gravity considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit are consistently derived from Einstein's general relativity. Analysis is made in the maximal slicing where the Poisson's equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the {\it general} hypersurface condition. Our formulation includes the anisotropic stress.

### The low-frequency radio emission in blazar PKS2155-304

We report radio imaging and monitoring observations in the frequency range 0.235 - 2.7 GHz during the flaring mode of PKS 2155-304, one of the brightest BL Lac objects. The high sensitivity GMRT observations not only reveal extended kpc-scale jet and FRI type lobe morphology in this erstwhile `extended-core' blazar but also delineate the morphological details, thanks to its arcsec scale resolution. The radio light curve during the end phase of the outburst measured in 2008 shows high variability (8.5%) in the jet emission in the GHz range, compared to the lower core variability (3.2%) seen at the lowest frequencies. The excess of flux density with a very steep spectral index in the MHz range supports the presence of extra diffuse emission at low frequencies. The analysis of multi wavelength (radio/ optical/ gamma-ray) light curves at different radio frequencies confirms the variability of the core region and agrees with the scenario of high energy emission in gamma-rays due to inverse Compton emission from a collimated relativistic plasma jet followed by synchrotron emission in radio. Clearly, these results give an interesting insight of the jet emission mechanisms in blazars and highlight the importance of studying such objects with low frequency radio interferometers like LOFAR and the SKA and its precursor instruments.

### Exact Initial Data for Black Hole Universes with a Cosmological Constant [Cross-Listing]

We construct exact initial data for closed cosmological models filled with regularly arranged black holes in the presence of $\Lambda$. The intrinsic geometry of the 3-dimensional space described by this data is a sum of simple closed-form expressions, while the extrinsic curvature is just proportional to $\Lambda$. We determine the mass of each of the black holes in this space by performing a limiting procedure around the location of each of the black holes, and then compare the result to an appropriate slice through the Schwarzschild-de Sitter spacetime. The consequences of the inhomogeneity of this model for the large-scale expansion of space are then found by comparing the lengths of curves in the cosmological region to similar curves in a suitably chosen Friedmann-Lemaitre-Robertson-Walker (FLRW) solution. Finally, we locate the positions of the apparent horizons of the black holes, and determine the extremal values of their mass, for every possible regular arrangement of masses. We find that as the number of black holes is increased, the large-scale expansion of space approaches that of an FLRW model filled with dust and $\Lambda$, and that the extremal values of the black hole masses approaches that of the Schwarzschild-de Sitter solution.

### Exact Initial Data for Black Hole Universes with a Cosmological Constant

We construct exact initial data for closed cosmological models filled with regularly arranged black holes in the presence of $\Lambda$. The intrinsic geometry of the 3-dimensional space described by this data is a sum of simple closed-form expressions, while the extrinsic curvature is just proportional to $\Lambda$. We determine the mass of each of the black holes in this space by performing a limiting procedure around the location of each of the black holes, and then compare the result to an appropriate slice through the Schwarzschild-de Sitter spacetime. The consequences of the inhomogeneity of this model for the large-scale expansion of space are then found by comparing the lengths of curves in the cosmological region to similar curves in a suitably chosen Friedmann-Lemaitre-Robertson-Walker (FLRW) solution. Finally, we locate the positions of the apparent horizons of the black holes, and determine the extremal values of their mass, for every possible regular arrangement of masses. We find that as the number of black holes is increased, the large-scale expansion of space approaches that of an FLRW model filled with dust and $\Lambda$, and that the extremal values of the black hole masses approaches that of the Schwarzschild-de Sitter solution.

### Astrophysical Prior Information and Gravitational-wave Parameter Estimation

The detection of electromagnetic counterparts to gravitational waves has great promise for the investigation of many scientific questions. It has long been hoped that in addition to providing extra, non-gravitational information about the sources of these signals, the detection of an electromagnetic signal in conjunction with a gravitational wave could aid in the analysis of the gravitational signal itself. That is, knowledge of the sky location, inclination, and redshift of a binary could break degeneracies between these extrinsic, coordinate-dependent parameters and the physical parameters, such as mass and spin, that are intrinsic to the binary. In this paper, we investigate this issue by assuming a perfect knowledge of extrinsic parameters, and assessing the maximal impact of this knowledge on our ability to extract intrinsic parameters. However, we find only modest improvements in a few parameters --- namely the primary component's spin --- and conclude that, even in the best case, the use of additional information from electromagnetic observations does not improve the measurement of the intrinsic parameters significantly.

### On the universal late X-ray emission of binary-driven hypernovae and its possible collimation

It has been previously discovered a universal power-law behaviour of the late X-ray emission (LXRE) of a "golden sample" (GS) of six long energetic GRBs, when observed in the rest-frame of the source. This remarkable feature, independent on the different isotropic energy (E_iso) of each GRB, has been used to estimate the cosmological redshift of some long GRBs. This analysis is here extended to a new class of 161 long GRBs, all with E_iso > 10^52 erg. These GRBs are indicated as binary-driven hypernovae (BdHNe) in view of their progenitors: a tight binary systems composed of a carbon-oxigen core (CO_core) and a neutron star (NS) undergoing an induced gravitational collapse (IGC) to a black hole (BH) triggered by the CO_core explosion as a supernova (SN). We confirm the universal behaviour of the LXRE for the "enlarged sample" (ES) of 161 BdHNe observed up to the end of 2015, assuming a double-cone emitting region. We obtain a distribution of half-opening angles peaking at 17.62{\deg}, with mean value 30.05{\deg}, and a standard deviation 19.65{\deg}. This, in turn, leads to the possible establishment of a new cosmological candle. Within the IGC model, such universal LXRE behaviour is only indirectly related to the GRB and originates from the SN ejecta, of a standard constant mass, being shocked by the GRB emission. The fulfillment of the universal relation in the LXRE and its independence of the prompt emission, further confirmed in this article, establishes a crucial test for any viable GRB model.

### Baryon number transfer could delay Quark-Hadron transition in cosmology [Cross-Listing]

In the early Universe, s.i. matter was a quark-gluon plasma. Both lattice computations and heavy ion collision experiments however tell us that, in the absence of chemical potentials, no plasma survives at $T <\sim 150\,$MeV. The cosmological QH transition, however, seems to have been a crossover; cosmological consequences envisaged when it was believed to be a phase transition no longer hold. In this paper we discuss whether even a crossover transition can leave an imprint that cosmological observations can seek or, viceversa, there are questions cosmology should still ask QCD specialists. In this context, we outline, first of all, that it is still unclear how baryons (not hadrons) could form at the cosmological transition. A critical role should be played by diquark states, whose abundance in the early plasma needs to be accurately evaluated. We estimate that, if the number of quarks belonging to a diquark state, at the eve of the cosmological transition, is $<\sim 1:10^6$, its dynamics could be modified by the process of B-transfer from plasma to hadrons. In turn, by assuming B-transfer to cause just mild perturbations and, in particular, no entropy input, we study the deviations from the tracking regime, in the frame of SCDEW models. We find that, in some cases, residual deviations could propagate down to primeval nucleosynthesis.