## Recent Postings from Special Topics

### Super-Eddington Mechanical Power of an Accreting Black Hole in M83

http://www.sciencemag.org/content/early/2014/02/26/science.1248759

Abstract

Mass accretion onto black holes releases energy in the form of radiation and outflows. While the radiative flux cannot substantially exceed the Eddington limit, at which the outgoing radiation pressure impedes the inflow of matter, it remains unclear whether the kinetic energy flux is bounded by this same limit. Here we present the detection of a radio/optical structure, powered by outflows from a non-nuclear black hole. Its accretion disk properties indicate that this black hole is less than 100 solar masses. The optical/IR line emission implies an average kinetic power of 3 × 1040 erg s−1, higher than the Eddington luminosity of the black hole. These results demonstrate kinetic power exceeding the Eddington limit over a sustained period, which implies greater ability to influence the evolution of the black hole’s environment.

### The observable signature of late heating of the Universe during cosmic reionization

Felix will lead a discussion on the recent Nature paper (click here to get the article), which is about role of HMXBs in the reionisation of the universe.

### Astrotrends: interactively explore keyword trends in the literature

http://www.stefanom.org/playpen/Trends/keywords/

This interactive visualization shows the number of refereed Astronomy articles published each year, containing the selected keywords in their abstracts.

### Firewall controversy claims black hole event horizons as latest victim

#### Information Preservation and Weather Forecasting for Black Holes

(Submitted on 22 Jan 2014)

It has been suggested [1] that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the CPT invariance of quantum gravity and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that gravitational collapse produces apparent horizons but no event horizons behind which information is lost. This proposal is supported by ADS-CFT and is the only resolution of the paradox compatible with CPT. The collapse to form a black hole will in general be chaotic and the dual CFT on the boundary of ADS will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity.

http://arxiv.org/abs/arXiv:1401.5761

### Observation of the Optical and Spectral Characteristics of Ball Lightning

http://prl.aps.org/abstract/PRL/v112/i3/e035001

Ball lightning (BL) has been observed with two slitless spectrographs at a distance of 0.9 km. The BL is generated by a cloud-to-ground lightning strike. It moves horizontally during the luminous duration. The evolution of size, color, and light intensity is reported in detail. The spectral analysis indicates that the radiation from soil elements is present for the entire lifetime of the BL

### Citizen scientists discover gravitational lenses at record speed

http://www.symmetrymagazine.org/article/january-2014/citizen-scientists-discover-hidden-galaxies-at-record-speed

This week, encouraged by a program on the BBC, more than 55,000 citizen scientists powered up their computers, navigated to Spacewarps.org and, over the course of just 72 hours, made a difference to the future of astrophysics. [T]he first of the three daily episodes of the BBC television series Stargazing Live, which highlights astronomy research in the United Kingdom, included a challenge encouraging viewers to find [gravitational lenses] at the edge of space through SpaceWarps.org. The response was immense. Tens of thousands of people visited the website and, in just three days, made more than 6 million image classifications. The images that viewers classified were from infrared data taken with the CFHT telescope in Hawaii and the VISTA telescope in Chile by the VICS82 survey team, led by Jim Geach of the University of Hertfordshire. The patch of sky in question, though previously imaged with optical telescopes, had never before been searched for gravitational lenses in the infrared.

A preliminary analysis of citizen scientists’ work over the past week revealed a handful of new gravitational lenses, including one confirmed system that was found quickly enough that, during the second night’s TV program, researchers were able to point the UK’s eMerlin radio array at the system to study it further. In addition to kick-starting research into these dusty and distant galaxies, Marshall says that the overwhelming amount of interest shown by citizen scientists in the past week may also have implications for future data-intensive experiments like the Large Synoptic Survey Telescope.

Summary extracted and condensed from the original article.

### ITA/ITP Heidelberg Journal Club

The first 2014 meeting will be held on Tuesday, January 14th at 13:00 in the room 105 of Philosophenweg 12.

We will have two speakers and a discussion session.

Hope to see you there!

### Effect of increased gravitational acceleration in potato deep-fat frying

http://www.sciencedirect.com/science/article/pii/S0963996913005929

This work extends our previous studies on crust thickness evolution and evaporation front propagation during deep fat frying of potato sticks (French fries) by incorporating the effect of increased gravitational acceleration. Scaling of gravitational acceleration allows scaling of buoyancy forces which control the heat transfer from hot oil to potato surface. For this, a special device is constructed which permits (a) temperature recording at specified positions below the potato surface (i.e. 0.5, 1.0 and 1.5 mm), (b) exposure of only one surface of a potato stick to hot oil, (c) rotation of the exposed surface at orientations 0° (horizontal, top), 90° (vertical, side) and 180° (horizontal, bottom), and (d) execution of deep fat frying experiments at increased gravity levels (i.e. 1.8, 3.0, 6.0 and 9.0 · gearth). The latter is achieved by means of a large diameter centrifuge (European Space Agency). Temperature recordings and crust thickness evolution indicate that heat transfer during frying depends on gravity level but differently at different potato orientations. Most significant variations with gravity are found up to 3.0 · gearth and for 0° orientation. Moreover, crust thickness evolution diverges from the evaporation front propagation in all times supporting the notion of a wide evaporation zone rather than a sharp evaporation front.

### Searching the Internet for evidence of time travelers

Authors: Robert J. Nemiroff, Teresa Wilson
arXiv:1312.7128
(Submitted on 26 Dec 2013)

Time travel has captured the public imagination for much of the past century, but little has been done to actually search for time travelers. Here, three implementations of Internet searches for time travelers are described, all seeking a prescient mention of information not previously available. The first search covered prescient content placed on the Internet, highlighted by a comprehensive search for specific terms in tweets on Twitter. The second search examined prescient inquiries submitted to a search engine, highlighted by a comprehensive search for specific search terms submitted to a popular astronomy web site. The third search involved a request for a direct Internet communication, either by email or tweet, pre-dating to the time of the inquiry. Given practical verifiability concerns, only time travelers from the future were investigated. No time travelers were discovered. Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date.

### The martian soil as a planetary gas pump

http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys2821.html

Mars has an active surface, with omnipresent small dust particles and larger debris. With an ambient pressure below 10 mbar, which is less than 1% of the surface pressure on Earth, its CO2 atmosphere is rather tenuous. Aeolian processes on the surface such as drifting dunes, dust storms and dust devils are nevertheless still active1, 2, 3. The transport of volatiles below the surface, that is, through the porous soil, is unseen but needs to be known for balancing mass flows4, 5. Here, we describe a mechanism of forced convection within porous soils. At an average ambient gas pressure of 6 mbar, gas flow through the porous ground of Mars by thermal creep is possible and the soil acts as a (Knudsen) pump. Temperature gradients provided by local and temporal variations in solar insolation lead to systematic gas flows. Our measurements show that the flow rates can outnumber diffusion rates. Mars is the only body in the Solar System on which this can occur naturally. Our laboratory experiments reveal that the surface of Mars is efficient in cycling gas through layers at least centimetres above and below the soil with a turnover time of only seconds to minutes.

### Puzzling accretion onto a black hole in the ultraluminous X-ray source M 101 ULX-1

http://www.nature.com/nature/journal/v503/n7477/full/nature12762.html

There are two proposed explanations for ultraluminous X-ray sources1, 2 (ULXs) with luminosities in excess of 1039 erg s−1. They could be intermediate-mass black holes (more than 100–1,000 solar masses, ) radiating at sub-maximal (sub-Eddington) rates, as in Galactic black-hole X-ray binaries but with larger, cooler accretion disks3, 4, 5. Alternatively, they could be stellar-mass black holes radiating at Eddington or super-Eddington rates2, 6. On its discovery, M 101 ULX-14, 7 had a luminosity of 3 × 1039 erg s−1 and a supersoft thermal disk spectrum with an exceptionally low temperature—uncomplicated by photons energized by a corona of hot electrons—more consistent with the expected appearance of an accreting intermediate-mass black hole3, 4. Here we report optical spectroscopic monitoring of M 101 ULX-1. We confirm the previous suggestion8 that the system contains a Wolf-Rayet star, and reveal that the orbital period is 8.2 days. The black hole has a minimum mass of 5 , and more probably a mass of 20 −30 , but we argue that it is very unlikely to be an intermediate-mass black hole. Therefore, its exceptionally soft spectra at high Eddington ratios violate the expectations for accretion onto stellar-mass black holes9, 10, 11. Accretion must occur from captured stellar wind, which has hitherto been thought to be so inefficient that it could not power an ultraluminous source12, 13.

### What's So Special About Science (And How Much Should We Spend on It?)

#### What’s So Special About Science (And How Much Should We Spend on It?)

Scientific research probes the deepest mysteries of the universe and of living things, and it creates applications and technologies that benefit humanity and create wealth. This “Beauty and Benefits of Science” is the theme of this 2013 AAAS Annual Meeting.

The subject of my address is a different kind of mystery, although it is also related to this theme. It is the mystery of why society is willing to support an endeavor as abstract and altruistic as basic scientific research and an enterprise as large and practical as the research and development (R&D) enterprise as a whole. Put differently, it is the mystery that a unified scientific enterprise can be simultaneously the seed corn for economic advance and the confectionary corn syrup of pure, curiosity-driven scientific discovery.

### A Mixture of Ancient and Modern Understanding Concerning the Distance and Motion of the Moon

http://arxiv.org/abs/1311.2798

Ptolemy’s model of the Moon’s motion implied that its distance varies by nearly a factor of two, implying that its angular size should also vary by nearly a factor of two. We present an analysis of 100 naked eye observations of the Moon’s angular size obtained over 1145 days, showing regular variations of at least 3 arc minutes. Thus, ancient astronomers could have shown that a key implication of Ptolemy’s model was wrong. In modern times we attribute the variation of distance of the Moon to the combined effect of the ellipticity of the Moon’s orbit and the perturbing effect of the Sun on the Earth-Moon system. We show graphically how this affects the ecliptic longitudes and radial distance of the Moon. The longitude and distance “anomalies” are correlated with the Moon’s phase. This is illustrated without any complex equations or geometry.

### Majority is not Enough: Bitcoin Mining is Vulnerable

http://arxiv.org/abs/1311.0243

The Bitcoin cryptocurrency records its transactions in a public log called the blockchain. Its security rests critically on the distributed protocol that maintains the blockchain, run by participants called miners. Conventional wisdom asserts that the protocol is incentive compatible and secure against colluding minority groups, i.e., it incentivizes miners to follow the protocol as prescribed. We show that the Bitcoin protocol is not incentive- compatible. We present an attack with which colluding miners obtain a revenue larger than their fair share. This attack can have significant consequences for Bitcoin: Rational miners will prefer to join the selfish miners, and the colluding group will increase in size until it becomes a majority. At this point, the Bitcoin system ceases to be a decentralized currency.
Selfish mining is feasible for any group size of colluding miners. We propose a practical modification to the Bitcoin protocol that protects against selfish mining pools that command less than 1/4 of the resources. This threshold is lower than the wrongly assumed 1/2 bound, but better than the current reality where a group of any size can compromise the system.

# European agency selects mission themes, with X-ray telescope the biggest winner. http://www.nature.com/news/x-rays-top-space-agenda-1.14097

### Super-luminous supernovae on the rise

http://www.nature.com/nature/journal/v502/n7471/full/502310a.html

New observations suggest that certain extremely bright supernovae are not the nuclear explosions of very massive stars. Instead, they may be ordinary-mass events lit up by a potent central fountain of magnetic energy.

### Why does a beer bottle foam up after a sudden impact on its mouth?

http://arxiv.org/abs/1310.3747

A sudden vertical impact on the mouth of a beer bottle generates a compression wave that propagates through the glass towards the bottom. When this wave reaches the base of the bottle, it is transmitted to the liquid as an expansion wave that travels to free surface, where it bounces back as a compression wave. This train of expansion-compression waves drives the forced cavitation of existing air pockets, leading to their violent collapse. A cloud of very small daughter bubbles are generated upon these collapses, that expand much faster than their mothers due to their smaller size. These rapidly growing bubble clusters effectively act as buoyancy sources, what leads to the formation of bubble-laden plumes whose void fraction increases quickly by several orders of magnitude, eventually turning most of the liquid into foam.

### First results from the LUX dark matter experiment at the Sanford Underground Research Facility

Abstract:

The Large Underground Xenon (LUX) experiment, a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), was cooled and filled in February 2013. We report results of the first WIMP search dataset, taken during the period April to August 2013, presenting the analysis of 85.3 live-days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10^−46 cm^2 at a WIMP mass of 33 GeV/c^2. We find that the LUX data are in strong disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.

### Gauge-Gravity Duality and the Black Hole Interior

Donald Marolf*
Department of Physics, University of California, Santa Barbara, California 93106-9530, USA

Joseph Polchinski
Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106-4030, USA

Received 18 July 2013; published 21 October 2013

See accompanying Physics Viewpoint

We present a further argument that typical black holes with field theory duals have firewalls at the horizon. This argument makes no reference to entanglement between the black hole and any distant system, and so is not evaded by identifying degrees of freedom inside the black hole with those outside. We also address the Einstein-Rosen=Einstein-Podolsky-Rosen conjecture of Maldacena and Susskind, arguing that the correlations in generic highly entangled states cannot be geometrized as a smooth wormhole.

http://prl.aps.org/abstract/PRL/v111/i17/e171301

### Gamma-ray constraints on dark-matter annihilation to electroweak gauge and Higgs bosons

http://arxiv.org/abs/1310.6047

Gamma-ray constraints on dark-matter annihilation to electroweak gauge and Higgs bosons

Michael A. Fedderke, Edward W. Kolb, Tongyan Lin, Lian-Tao Wang

Dark-matter annihilation into electroweak gauge and Higgs bosons results in γ-ray emission. We use observational upper limits on the fluxes of both line and continuum γ-rays from the Milky Way Galactic Center and from Milky Way dwarf companion galaxies to set exclusion limits on allowed dark-matter masses. (Generally, Galactic Center γ-ray line search limits from the Fermi-LAT and the H.E.S.S. experiments are most restrictive.) Our limits apply under the following assumptions: a) the dark matter species is a cold thermal relic with present mass density equal to the measured dark-matter density of the universe; b) dark-matter annihilation to standard-model particles is described in the non-relativistic limit by a single effective operator O∝JDM⋅JSM, where JDM is a standard-model singlet current consisting of dark-matter fields (Dirac fermions or complex scalars), and JSM is a standard-model singlet current consisting of electroweak gauge and Higgs bosons; and c) the dark-matter mass is in the range 5 GeV to 20 TeV. We consider, in turn, the 34 possible operators with mass dimension 8 or lower with non-zero s-wave annihilation channels satisfying the above assumptions. Our limits are presented in a large number of figures, one for each of the 34 possible operators; these limits can be grouped into 13 classes determined by the field content and structure of the operators. We also identify three classes of operators (coupling to the Higgs and SU(2)L gauge bosons) that can supply a 130 GeV line with the desired strength to fit the putative line signal in Fermi data, while saturating the relic density and satisfying all other indirect constraints we consider.

### Slowly fading super-luminous supernovae that are not pair-instability explosions

Pair instability supernovae or weird coupling of a SN and a magnetar?

http://www.nature.com/nature/journal/v502/n7471/pdf/nature12569.pdf

### Journal group for the Anton Pannekoek

Let’s try if this works.

### Spoof paper reveals little or no scrutiny at many open-access journals

Who’s afraid of peer review?

by John Bohannon

Science,  4 October 2013,  Vol. 342 no. 6154 pp. 60-65  (DOI: 10.1126/science.342.6154.6)

… I created a scientific version of Mad Libs. The paper took this form: Molecule X from lichen species Y inhibits the growth of cancer cell Z. To substitute for those variables, I created a database of molecules, lichens, and cancer cell lines and wrote a computer program to generate hundreds of unique papers. …

A spoof paper concocted by Science reveals little or no scrutiny at many open-access journals.

(Bonus: accompanying infographic by Randall Munroe.)

### Black-Hole Bombs and Photon-Mass Bounds [arXiv gr-qc]

Black-Hole Bombs and Photon-Mass Bounds (Pani P., et al.)

Generic extensions of the standard model predict the existence of ultralight bosonic degrees of freedom. Several ongoing experiments are aimed at detecting these particles or constraining their mass range. Here we show that massive vector fields around rotating black holes can give rise to a strong superradiant instability which extracts angular momentum from the hole. The observation of supermassive spinning black holes imposes limits on this mechanism. We show that current supermassive black hole spin estimates provide the tightest upper limits on the mass of the photon (mv<4×10^{-20} eV according to our most conservative estimate), and that spin measurements for the largest known supermassive black holes could further lower this bound to mv<10^{-22} eV. Our analysis relies on a novel framework to study perturbations of rotating Kerr black holes in the slow-rotation regime, that we developed up to second order in rotation, and that can be extended to other spacetime metrics and other theories.

http://arxiv.org/abs/arXiv:1209.0465

### http://arxiv.org/pdf/1309.2225.pdf

The Muon Anomalous Magnetic Moment and the Pion Polarizability

### What is next for the Kepler mission?

White papers have been released by NASA into what type of mission Kepler can pursue with only two working reaction wheels. It would be interesting to discuss some of the more realistic and far-out-there options open to Kepler!

Full details are at: http://keplerscience.arc.nasa.gov/TwoWheelWhitePapers.shtml

A good summary of some of the ideas is provided at:

www.astrobites.org/2013/09/09/whats-next-for-kepler/

### Periastron Advance in Spinning Black Hole Binaries: Comparing Effective-One-Body and Numerical Relativity

http://arxiv.org/abs/1309.0544

We compute the periastron advance using the effective-one-body formalism for binary black holes moving on quasi-circular orbits and having spins collinear with the orbital angular momentum. We compare the predictions with the periastron advance recently computed in accurate numerical-relativity simulations and find remarkable agreement for a wide range of spins and mass ratios. These results do not use any numerical-relativity calibration of the effective-one-body model, and stem from two key ingredients in the effective-one-body Hamiltonian: (i) the mapping of the two-body dynamics of spinning particles onto the dynamics of an effective spinning particle in a (deformed) Kerr spacetime, fully symmetrized with respect to the two-body masses and spins, and (ii) the resummation, in the test-particle limit, of all post-Newtonian (PN) corrections linear in the spin of the particle. In fact, even when only the leading spin PN corrections are included in the effective-one-body spinning Hamiltonian but all the test-particle corrections linear in the spin of the particle are resummed we find very good agreement with the numerical results (within the numerical error for equal-mass binaries and discrepancies of at most 1% for larger mass ratios). Furthermore, we specialize to the extreme mass-ratio limit and derive, using the equations of motion in the gravitational skeleton approach, analytical expressions for the periastron advance, the meridional Lense-Thirring precession and spin precession frequency in the case of a spinning particle on a nearly circular equatorial orbit in Kerr spacetime, including also terms quadratic in the spin.

### Periastron Advance in Spinning Black Hole Binaries: Gravitational Self-Force from Numerical Relativity

http://arxiv.org/abs/1309.0541

We study the general relativistic periastron advance in spinning black hole binaries on quasi-circular orbits, with spins aligned or anti-aligned with the orbital angular momentum, using numerical-relativity simulations, the post-Newtonian approximation, and black hole perturbation theory. By imposing a symmetry by exchange of the bodies’ labels, we devise an improved version of the perturbative result, and use it as the leading term of a new type of expansion in powers of the symmetric mass ratio. This allows us to measure, for the first time, the gravitational self-force effect on the periastron advance of a non-spinning particle orbiting a Kerr black hole of mass M and spin S = -0.5 M^2, down to separations of order 9M. Comparing the predictions of our improved perturbative expansion with the exact results from numerical simulations of equal-mass and equal-spin binaries, we find a remarkable agreement over a wide range of spins and orbital separations.

### Paperscape Map

Paperscape is a tool to visualise the arXiv, an open, online repository for scientific research papers. The Paperscape map currently includes all (non-withdrawn) papers from the arXiv and is updated daily.

Each paper in the map is represented by a circle, with the area of the circle proportional to the number of citations that paper has. In laying out the map, an N-body algorithm is run to determine positions based on references between the papers. There are two “forces” involved in the N-body calculation: each paper is repelled from all other papers using an anti-gravity inverse-distance force, and each paper is attracted to all of its references using a spring modelled by Hooke’s law. We further demand that there is no overlap of the papers.

The map is rendered simply as a solid circle for each paper. The colour of the circle denotes the arXiv category of the paper, and the brightness indicates age. Brightness is sometime difficult to discern, and we are working on adding a heat-map overlay to indicate clearly the areas of the map which have the most recent activity.

As you zoom in on the map labels will start to appear on individual papers. These labels are (mostly) automatically extracted by analysing word frequency in the title and abstract of the paper, and are generally indicative of the subject matter of that paper. Zooming in closer also shows the author(s) of the paper. If a paper is deemed to be a review paper, or a set of lectures, this is noted.

References (and citation counting) are extracted by processing the TeX/LaTeX and PDF source obtained from the arXiv. This is done automatically each morning, and the map is finished updating about 3 or 4 hours after the arXiv’s new listing is announced. Some categories (noticeably hep-th and hep-ph) have better reference extraction than others and so the map for these areas has more variation in paper size and more structure. We are working on improving the reference extraction.

### Astrobetter Ethics and Diversity Poll

http://www.astrobetter.com/ethics-and-diversity-poll

C. Casey (IfA, U. Hawaii)  & K. Sheth (NRAO)

“The culture of academia can be rife with uncomfortable situations, some more clearcut than others.  We all began our research careers with expectations that both ourselves and our colleagues will behave ethically. Sometimes reality might be surprising.  Your judgement might be very different than your colleague’s down the hall due to cultural differences, the different subfields you work in, or different experiences in your careers.  Your own behavior might also evolve over the course of your career.”

“Below, we have collated 25 hypothetical scenarios that astronomers might face in their careers and we’re going to ask you to rank them on a continuous scale from 1 to 9 (1=bad, 9=good).  [...]  The results of this survey will be collated and shared in another post in two weeks’ time.  [...]  If you are struggling to figure out who to evaluate in each scenario that’s fine. We left several purposefully ambiguous and only ask that you evaluate your level of comfort with the situation. [...]  These are intended to lead to broader discussion within a group.”

### Rainbow Colo(u)r Map (Still) Consider Harmful

Following our discussion today about colour maps, this is an interesting paper that discusses way we should not (in some cases) use colour maps. It is a short paper published by IEEE computer society but its analysis is applicable to astronomy. Mike Wheatland and Stuart Gilchrist were the people that pointed out this paper to me earlier in the year.

http://www.jwave.vt.edu/~rkriz/Projects/create_color_table/color_07.pdf

### Determination of the intrinsic Luminosity Time Correlation in the X-ray Afterglows of GRBs

Gamma-ray bursts (GRBs), which have been observed up to redshifts z approx 9.5 can be good probes of the early universe and have the potential of testing cosmological models. The analysis by Dainotti of GRB Swift afterglow lightcurves with known redshifts and definite X-ray plateau shows an anti-correlation between the rest frame time when the plateau ends (the plateau end time) and the calculated luminosity at that time (or approximately an anti-correlation between plateau duration and luminosity). We present here an update of this correlation with a larger data sample of 101 GRBs with good lightcurves. Since some of this correlation could result from the redshift dependences of these intrinsic parameters, namely their cosmological evolution we use the Efron-Petrosian method to reveal the intrinsic nature of this correlation. We find that a substantial part of the correlation is intrinsic and describe how we recover it and how this can be used to constrain physical models of the plateau emission, whose origin is still unknown. The present result could help clarifing the debated issue about the nature of the plateau emission.

### weakling-magnetar-reveals-hidden-strength

Francine Berman, Vint Cerf

On 22 February, the U.S. Office of Science and Technology Policy (OSTP) released a memo calling for public access for publications and data resulting from federally sponsored research grants (1). The memo directed federal agencies with more than \$100 million R&D expenditures to “develop a plan to support increased public access to the results of research funded by the Federal Government.” Perhaps even more succinctly, a subsequent New York Times opinion page sported the headline “We Paid for the Research, So Let’s See It” (2). So who pays for data infrastructure?

### The Sound of a Fermi Gamma-ray Burst

http://blogs.nasa.gov/GLAST/2012/06/21/post_1340301006610/

Gamma rays from GRB 080916C collected by the Fermi Large Area Telescope and converted into music.

### Formation of sharp eccentric rings in debris disks with gas but without planets

Formation of sharp eccentric rings in debris disks with gas but without planets
Authors: W. Lyra & M. Kuchner
Nature, 499, 184–187 (11 July 2013), doi:10.1038/nature12281

‘Debris disks’ around young stars (analogues of the Kuiper Belt in our Solar System) show a variety of non-trivial structures attributed to planetary perturbations and used to constrain the properties of those planets. However, these analyses have largely ignored the fact that some debris disks are found to contain small quantities of gas, a component that all such disks should contain at some level. Several debris disks have been measured with a dust-to-gas ratio of about unity, at which the effect of hydrodynamics on the structure of the disk cannot be ignored. Here we report linear and nonlinear modelling that shows that dust–gas interactions can produce some of the key patterns attributed to planets. We find a robust clumping instability that organizes the dust into narrow, eccentric rings, similar to the Fomalhaut debris disk. The conclusion that such disks might contain planets is not necessarily required to explain these systems.

Subject terms: Exoplanets, Computational astrophysics

### THE HELIOTAIL REVEALED BY THE INTERSTELLAR BOUNDARY EXPLORER

Recent combined observations from the first three years of Interstellar Boundary Explorer (IBEX) data allow us to examine the heliosphere’s downwind region—the heliotail—for the first time. In contrast to a preliminary identification of a narrow “offset heliotail” structure, we find a broad slow solar wind plasma sheet crossing essentially the entire downwind side of the heliosphere at low to mid-latitudes, with fast wind tail regions to the north and south. The slow wind plasma sheet exhibits the steepest ENA spectra in the IBEX sky maps, appears as a two-lobed structure (lobes on the port and starboard sides), and is twisted in the sense of (but at a smaller angle than) the external magnetic field. The overall heliotail structure clearly demonstrates the intermediate nature of the heliosphere’s interstellar interaction, where both the external dynamic and magnetic pressures strongly affect the heliosphere.

http://iopscience.iop.org/0004-637X/771/2/77/pdf/0004-637X_771_2_77.pdf

### This is a story of how cosmic x-rays became music. A first step turned x-rays emitted by the binary system of EX Hydrae into sounds. A second step made these sounds into music.

http://www.cfa.harvard.edu/sed/projects/star_songs/index.html