Day 260

Monday.  Solar eclipse trip was great, this past weekend.
Tuesday (gah!).  
Wednesday (aaagh!).  Reading for GalSim takes a loooong time.  And the meeting minutes for various Euclid.  Went climbing with Burke at Ironworks last night; that was fun.  Climbed an easy 5.10A.  My arms are still OK.
Thursday.  Went running last night, and hurt my left knee.  Arms -- OK.  I guess the morning yoga helps with my arm muscle usage.


1205.4712
Orbit-based dynamical models of the Sculptor dSph galaxy
Breddels, Helmi, van den Bosch, van de Ven, Battaglia


...


1205.4715
Principal component abundance analysis of microlensed bulge dwarf and subgiant stars
Andrews, Weinberg, Johnson, Bensby, Feltzing


First PC (PC1): strong contribution from alpha-elements (relative contributions of Type II and Type Ia SNe).  PC2: Na-Ni correlation (likely product of metallicity-dependent Type II SNe yields).   Distribution of PC1 is bimodal (recovered from bimodal [Fe/H] values).  Enrichment history anomaly seen in outlier values of PCs.  Thin and thick disk dwarfs yield a nearly identical PC1.  Metal-rich and metal-poor bulge dwarfs track kinematically selected thin and thick disk dwarfs, respectively, suggesting broadly similar alpha-enrichment histories.  Disk PC2 is dominated by a Y-Ba correlation (likely indicating a greater contribution of s-process enrichment from asymptotic giant branch stars in the disk, compared to the more rapidly forming bulge).


1205.4716
Chemical tracers of high-metallicity environments
Bayet, Davis, Bell, Viti


Properties of molecular gas in metal-rich environments (e.g., in ETGs).  Photon-dominated region (PDR) chemistry in a wide range of physical conditions appropriate for these sources considered.  Derive fractional abundances of 20 most chemically reactive species as a function of metallicity, optical depth, and various volume number gas densities, FUV radiation fields, and CR ionization rates.  Also investigate the response of the chemistry to the changes in alpha-element enhancement as seen in ETGs.  With increasing metallicity, CS, H2S, H2CS, H2O, H3O+, HCO+ and H2CN seem invariant, whereas C+, CO, C2H, CN, HCN, HNC and OCS appear to be the species most sensitive to change.  The most sensitive species to the change in the fractional abundance of alpha-elements are C+, C, CN, HCN, HNC, SO, SO2, H2O and CS.  Finally, provide line brightness ratios for the most abundant species, especially in the range observable with ALMA.  Discussion of favorable line ratios to use for estimation of super-solar metallicities and alpha-elements are also provided.


1205.4724
The origin of the microlensing events observed towards the LMC and the stellar counterpart of the Magellanic stream
Besla, Hernquist, Loeb


Novel theory to explain the long-standing puzzle of the nature of the microlensing events reported towards the LMC by MACHO and OGLE collaborations.  Propose: population of tidally stripped stars from SMC located 4-10 kpc behind a lensing population of LMC disk stars can naturally explain the observed event durations, event frequency and spatial distribution of the reported events.  Favors scenario for the interaction history of MC where the clouds are on their first infall towards the MW and the SMC has recently collided with the LMC, leading to a large number of faint sources distributed non-uniformly behind the LMC disk.  Owing to the tidal nature of the source population, the sources exhibit a range of distances and velocities wrt the LMC lenses, naturally explaining the observed range of event durations (30-220 days).  Assuming a detection efficiency of 30-50%, find event frequencies of 1-2/yr in the central regions of the LMC disk; comparable to the observed rate for the MACHO survey, ~2/yr.  A lower detection efficiency of 10% is comparable to OGLE results.  Observational tests: SMC stars are low-metallicity; exhibit high velocities relative to LMC disk stars (detectable via proper motion studies); there should exist a stellar counterpart to the gaseous Magellanic Stream and Magellanic Bridge with a Vband surface brightness > 34 Mag/ arcsec^2.


1205.5028
Type Ia single degenerate survivors must be overluminous
Shappee, Kochanek, Stanek


In the SD channel of SN Ia explosion, a MS donor star survives the explosion but it is stripped of mass and shock heated.  This results in a companion that becomes significantly more luminous (10-1e3 Lsun) for a long period of time (1e3-4 years).  The lack of such a luminous "leftover" strain the LMC SNe remnant SNR 0609-67.5 provides another piece of evidence against the SD scenario, while also none of the proposed survivors of Tycho (including Tycho G) could plausibly be the donor star.  Luminous donors closer than 10Mpc should be observable with the HST starting ~2years post-peak, and should be easily tested.


1205.5037
A huge reservoir of ionized gas around the Milky Way: accounting for the missing mass?
Gupta, Mathur, Krongold, Nicastro, Galeazzi


Many galaxies contain a large reservoir of ionized gas with temperatures of about 1e5K (HST observations).  Reeert Chandra probing a hotter phase of CGM of MW at 1e6K.  This phase of the CGM is massive, extending over a large region around the MW (radius of 100 kpc).  The mass content of this phase is over 1e10 Msun, many times more than cooler gas phases and comparable to the total baryonic mass in the disk of the Galaxy.  THe missing mass of the galaxy appears to be in this warm-hot gas phase.


1205.5223
Determination of neutrino mass hierarchy by 21cm line and CMB B-mode polarization observations
Oyama, Shimizu, Kohri


Ongoing and future observations for both the 21 cm line and the CMB B-mode polarization produced by a CMB lensing, and study their sensitivities to the effective number of neutrino species, the total neutrino mass, and the neutrino mass hierarchy.  Find: combining the CMB observations with future squire kilometer arrays optimized for 21 cm line such as Omniscope can determine the neutrino mass hierarchy at 95% CL.  Also show that the combination of Planck+ Polarbear and SKA can strongly improve the bounds of the total neutrino mass and the effective number of neutrino species to be Delta Sigma m_nu~0.15eV and Delta N_nu~0.35 at 95% CL, respectively.

Day 259

Wednesday.  See if I can at least read yesterday's astro-ph...


1205.2697
Large scale structure in absorption: gas within and around galaxy voids
Tejos, Morris, Crighton, Theuns, Altay, Finn


Properties of HI LyA forest within and around galaxy voids at z<0.1.  Find significant excess (>99% cl) of LyA systems at the edges of galaxy voids wrt a random distribution, on 5 Mpc/h scales.  No significant difference in the number of systems inside voids.  Report differences between both column density and Doppler parameter distributions of Ly-A systems found inside and at the edge of galaxy voids at >98 and >90% CL, respectively.  [?]  Low density environments (voids) have smaller values for both N_HI and b_HI than higher ones (edge of voids).  Consistent with 3 types of Ly-a systems: (1) containing embedded galaxies, and so directly correlated with galaxies ('halo-like') (2) correlated with galaxies only because they lie in the same over dense LSS, and (3) associated with under-dense LSS with a very low auto-correlation amplitude (~random) that are not correlated with luminous galaxies.  Latter drive in structures still growing linearly from the primordial density fluctuations inside galaxy voids that have not formed galaxies because of their low densities; estimate 25-30% of the current LyA population account for these absorbers.  'halo-like' absorbers (assuming they must have high column density) account for 12-15%.

Day 258

Tuesday.  Planning for the weekend trip.


1205.2395
Type 1b/c supernovae with and without gamma-ray bursts
Modjaz


Connection between long GRBs and SNe Ib/c from stripped stars has been well-established, one outstanding question is what conditions and factors lead to each kind of explosion in massive stripped stars---so, compare SNe Ib/c with and without GRBs.  70 SNe of types IIb, Ib, Ic and Ic-bl (x3 previously known) of well-observed Stripped SNe.  Demonstrate that a meta-analysis of the 3 published SN Ib/c metallicity data sets indicates that SNe Ic erupt from more metal-rich environments than SNe Ib, while SNe Ic-bl with GRBs still prefer more metal-poor sites than those without GRBs.


1205.2422
Spatial urvature and cosmological tests of general relativity
Dossett, Ishak


Study the effect of curvature on constraints on parameters used to test General Relativity (GR) at cosmological scales (MG parameters).  Constraints are (of course) weakened.  Assumption of a spatially flat model on a (spatially) curved universe causes an artificial shift (bias) in the constraints of MG parameters, in some cases causing an apparent deviation from GR .  When using future high precision data to perform tests, spatial curvature must be included in the parameter analysis along with other ore parameters and the MG parameters.


1205.2429
The habitable zone and extreme planetary orbits
Kane, Gelino


Describe the development of the Habitable Zone concept, application to the Solar System, and to exoplanetary systems.  Apply to extreme eccentric orbits, and show how they may still retain life bearing properties depending upon the percentage of the total orbit which is spent within the Habitable Zone.


1205.2522
Astrophysical objects observed by the MESSENGER X-ray spectrometer during Mecury flybys
Bannister, Fraser, Lindsay Martindale, Talboys


Find: 2 X-ray peaks attributed in earlier work to the detection of supra thermal electrons from the Mercury magnetosphere are likely to contain a significant number of events that are of astrophysical origin.  ... [??]


1205.2533
On galaxies and homology
Novak, Jonsson, Primack, Cox, Dekel


"A set of galaxies is homologous if they are the same in all respects up to a set of 3 scaling constants, which may differ from one galaxy to the next."  Find: a set of hydrodynamic simulated galaxy merger remnants is significantly closer to homologous when the dimensional length constant is taken to be the radius containing equal amounts of DM and baryonic matter, rather than the usual baryonic half-mass radius. Once the correct dimensional scaling constants are used, the stellar velocity dispersion anisotropy is essentially the sole source of the variation in the kinematic structure of these simulated merger remnants.  


1205.2537
Cosmic microwave and infrared backgrounds cross-correlation for ISW detection
Ilic


As the title says:  The S/N can be up to 6 to 7 sigma in the ideal case (depending on the frequency).  Realistically, 2-5 sigma.


1205.2693
The velocity dispersion and mass function of the outer halo globular cluster Palomar 4
Frank, Hilker, Baumgardt, Cote, Grebel, Haghi, Küpper, Djorgovski


...and the cluster's surface brightness profile based on WFPC2; broad-band imaging with low-res spectra at Keck II.  Mean cluster velocity of 72.55pm0.22 km/s, velocity dispersion of 0.87pm0.18 km/s.  The global mass function of the cluster, in the mass range 0.55<m<0.85 Msun, is shallower than a Kroupa mass function and the clutter is significantly depleted in low-mass stars in its center compared to its outskirts.  Relaxation time of Pal4 is order Hubble time; so there must be mass segregation in this cluster.  Total cluster mass of 29.8k Msun.  Consistent with Newtonian, below prediction of MOND.  Dynamics of star clusters in the outer Galactic halo can hardly be explained by MOND.


1205.2694
Shaping the galaxy stellar mass function with supernova- and AGN-driven winds
Puchwein, Springel


Show that an energy-driven outflow model in which the wind velocity decreases and the wind mass loading increases in low-mass galaxies, as suggested by observations, can produce a good match to the low-mass end of the observed galaxy stellar mass function.  High-mass end can be recovered simultaneously if AGN feedback and correction for diffuse stellar light missed in observations are included.  Good agreement with z=1 and z=2 stellar mass function, and observed z evolution of cosmic SFR density.  Suggests that the mass flux in the real galactic winds should strongly increase towards low-mass galaxies.  Without this assumption, an overproduction of galaxies at the faint-end of the galaxy luminosity function seems inevitable in these models.  [Tsaliakovich & Hirata paper relevant here?]

Day 257

Monday.  Didn't read astro-ph as I wanted to over the weekend...  Tommy is back from Italy!  Will attend his second graduation ceremony.

1205.2368

High-velocity outflows without AGN feedback Eddington-limited star formation in compact massive galaxies

Diamond-Stanic, Moustakas, Tremonti, Coil, Hickox, Robaina, Rudnick, Sell

Present the discovery of compact, obscured star formation in galaxies at z~0.6 that exhibit >1000 km/s outflows.  With HST/WISE, estimate SFR surface densities of 3000 Msun/yr/kpc^2, comparable to the Eddington limit from radiation pressure on dust grains.  Argue that feedback associated with a compact starburst in the form of radiation pressure from massive stars and ram pressure from supernovae and stellar winds is sufficient to produce the high-velocity outflows observed, without the need to invoke feedback from an AGN.

1205.2369

The Atacama cosmology telescope: relation between galaxy cluster optical richness and Sunyaev-Zel'dovich effect

Sehgal,..  Das, Devlin, Dunkley, ... Halpern, ... Hughes, .. Lin, et al

Measured SZ flux from 474 optically-selected MaxBCG clusters that fall within the ACN equatorial survey region; covers 510 sq deg and overlaps stripe 82 of SDSS.  Stacked SZ flux on 52 X-ray-selected MCXC clusters in equatorial and southern ACT sure region, covering 455 sqdeg.  Find: measured SZ flux from the x-ray selected clusters is consistent with expectations; but from optically selected clusters, it is both significantly lower than expectations and lower than the recovered SZ flux measured by Planck.  Suspect: significant offset between optically-selected brightest cluster galaxies (BCGs) and the SZ centers (ACT has finer resolution so is more sensitive to this); such offsets can arise due to either an intrinsic physical separation between the BCG and the center of the gas concentration or from misidentification of the cluster BCG.  Find: entire discrepancy for both ACT and Planck can be explained by assuming that the BCGs are offset from the SZ maxima with a uniform random distribution between 0 and 1.5 Mpc.  In contrast, the physical separation between BCGs and X-ray peaks for an X-ray selected subsample of MaxBCG clusters shows a much narrower distribution that peaks within 0.2 Mpc.  Conclude that while offsets between BCGs and SZ peaks may be an important component in explaining the discrepancy, it is likely that a combination of factors is responsible for the ACT and Planck measurements. 

1205.2370

AzTEC half square degree survey of the SHADES fields -- II. Identifications, redshifts, and evidence for large-scale structure

Michalowski, et al

Blind sub-mm survey, redshift distribution (median z~2.2) of galaxies (down to 1mJy) similar to SCUBA.

1205.2373

Residual Cooling and persistent star formation amid AGN feedback in Abell 2597

Tremblay et al

* Abell2597: shows x-ray and radio "cavities" that seem to be evidence of energetic outflow from the central region.

AGN heating and ICM cooling in the BCG of Abell2597 studied.  ... Conclude cooling ICM is the dominant contributor of the cold gas reservoir fueling SF and AGN activity in this BCG.

1205.2374

Multiphase signatures of AGN feedback in Abell 2597

Tremblay, et al

Extensive kpc-scale X-ray cavity network, as well as 15 kpc filament of slft-excess gas exhibiting strong spatial correlation with archival VLA radio data.  Filament may be associated with multiphase (1e3-1e7 K) gas that has been entrained and dredged up by the propagating radio source.  ...

1205.2375

Cosmology in 2D: the concentration-mass relation for galaxy clusters

Giocoli, Meneghetti, Ettori, Moscardini

Systematic study of the measures of the mass and concentration estimated by fitting the convergence profile of a large sample of mock galaxy cluster size lenses.  Main contribution to the bias in mass and in concentration is due to the halo triviality and second to the presence of substructures within the host halo virial radius.  Knowing the cluster elongation along the line of sight helps in correcting the mass bias, but still keeps a small negative bias for the concentration.  If these mass and concentration biases characterize the galaxy cluster sample of a wide field survey, it will be difficult to well recover within one sigma the cosmological parameters that mainly influence the c-M relation, using as reference a 3d c-M relation measured in cosmological N-body simulation.  In this work, propose how to correct the c-M relation for projection effects and for adiabatic contraction and suggest to use these as reference for real observed data. Correcting mass and concentration estimates gives a measurement of the cosmological parameter within 1-sigma confidence contours.

* I need to read this for the SM cluster project.

1205.2384

Hubble flows and gravitational potentials in observable universe

Eingorn, Zhuk

Consider the Universe deep inside of the cell of uniformity.  Inhomogeneously distributed discrete structures disturb the BG Friedmann model.  Propose mathematical models with conformally flat, hyperbolic and spherical spaces; obtain the gravitational potential for an  arbitrary number of randomly distributed inhomogeneities.  In the cases of flat and hyperbolic spaces, the potential is finite at any point, including spatial infinity, and valid for an arbitrary number of gravitating sources.  For these two models, investigate the motion of test masses (dwarf galaxies) in the vicinity of one of the inhomogeneities.  Show that there is a distance from the inhomogeneity, at which the cosmological expansion prevails over the gravitational attraction and where test masses form the Hubble flow.  For a group of galaxies, it happens at a few Mpc and the radius of the zero-velocity sphere is of the order 1 Mpc, which is very close to observations.  Outside of this sphere, the dragging effect of the gravitational attraction goes very fast to zero.

Day 256

Friday.  2am telecon with Benjamin, Filipe, Xun.  6am telecon with Tim, Edo, Zahra, Zeinab, Ole, Patrick.  I need to take a shower.  Let's see if I can read an astro-ph before 10am...


1205.1799
Asymmetric velocity anisotropies in remnants of collisionless mergers
Sparre, Hansen


Typical analysis of DM haloes assume spherically symmetric velocity distributions, but has not been explicitly tested.  Find: velocity anisotropy (differences in the radian and tangential velocity dispersion) has a strong dependence on direction; it depends on the merger history, explain why a large diversity is seen in the velocity anisotropy profiles in the outer parts of high-res simulations of haloes.


1205.1800
Deep silicate absorption features in Compton-thick AGN predominantly arise due to dust in the host galaxy
Goulding et al


As the title says.  Use Spitzer IRS to measure Si absorption features; explore the origin of MIR dust extinction in all 20 nearby AGN with hard X-ray SED.  Conclude that the dominant contribution to the observed MIR dust extinction is dust located in the host galaxy (disturbed morphologies, dust lanes, galaxy inclination angles), and not necessarily a compact obscuring torus surrounding the central engine.


1205.1801
Energetic galaxy-wide outflows in high-redshift ultra-luminous infrared galaxies hosting AGN activity
Harrison, et al


8 high-z ULIRGS with AGN activity, includes SMGs.  Targets have moderate radio luminosities typical of high-z ULIRGs (not radio-loud AGNs).  Decouple kinematic components due to the galaxy dynamics and mergers from outflows.  Find evidence in the most luminous systems for the signatures of LS energetic outflows: broad OIII emission across 4-15 kpc, with high velocity offsets from systemic redshifts (850 km/s); likely to unbind gas from the host galaxies.  The radiative power of the AGN, as opposed to SF or radio jets, is likely to dominate the driving outflows.  Suggest that galaxies observed may represent a key stage in the evolution of massive galaxies.


1205.1803
Constraining tidal dissipation in stars from the destruction rates of exoplanets
Penev, Jackson, Spada, Thom


Use distribution of extrasolar planets in circular orbits around stars with surface convective zones detected by ground based transit searches to constrain how efficiently tides raised by the planet are dissipated on the parent star.  Conclude that the population of currently knoon planets is inconsistent with Q*<1e7 at 3 sigma.  Q* required for orbital circularization is 1e5 to 1e7; suggests different dissipation mechanisms between the two, most likely due to the different tidal forcing frequencies relative to stellar rotation frequency for star-star vs planet-star systems.


1205.1808
A population of dust-rich quasars at z~1.5
Dai et al


Herschel SPIRE (250, 350, and 500 um) detections of 32 quasars with 0.5<z<3.6 from Herschel Multi-tiered Extragalactic Survey (HerMES), from 326 quasars in the Lockman hole Field.  Construct rest-frame SEDs from UV to MIR for all sources, and to the FIR for the 32 objects.  Most quasars with FIR detection show dust temperatures in the range of 25K to 60K, with a mean of 34K.  The FIR luminosities range from 1e11.3 to 1e13.5 Lsun (ULIRG or HLIRGs).  These FIR-detected quasars may represent a dust-rich population, but with lower redshifts and fainter luminosities than quasars observed at ~1mm.  Their FIR properties cannot be predicted from shorted wavelengths (0.3-20 um, rest-frame), and the bolometric luminosities derived using the 5100A index may be underestimated for these FIR-detected quasars.  Regardless of redshift, observe a decline in the relative strength of FIR luminosities for quasars with higher NIR luminosities.


1205.1843
Photometric properties of void galaxies in the Sloan digital sky survey DR7 data release
Hoyle, Vogeley, Pan


Photometric properties of 88k void galaxies; compare them to galaxies in higher density environments.  Find 1054 dynamically distinct voids with R>10 Mpc/h.  Voids are under dense (<-0.9 in their centers).  Color (u-r) as indicator of SF activity; inverse concentration index as indication of galaxy type.  Void galaxies are statistically bluer than galaxies found in higher density environments with the same magnitude distribution.  Little variation in void galaxy properties as function of distance from void center (though dwarf void galaxies may live loser to the center.  All void galaxies live in very similar density environments.

Day 255

Thursday.  Must read a lot till the end of the week; then a 6am telecon.


1205.1507
The dynamics, appearance and demographics of relativistic jets triggered by tidal disruption of stars in quiescent supermassive black holes
De Colle, Guillochon, Naiman, Ramirez-Ruiz


Consequences of a model in which relativistic jets can be triggered in quiescent massive black holes when a geometrically thick and hot accretion disk forms as a result of the tidal disruption of a star.  Estimate power, thrust, and lifetime of the jet, use mass accretion history onto the BH as calculated by detailed hydrodynamic simulations of the tidal disruption of stars.  Determine the states of the ISM in various types of quiescent galactic nuclei, and describe how this can affect jets propagating through it.  Study the dynamics of the jet, propagation of which is regulated by the density stratification of the environment and by its inception history.  The breaking of symmetry involved in transitioning from one to 2d is crucial, and leads to qualitatively new phenomena.  Many of the observed properties of a Swift GRB event can be understood as resulting from accretion onto and jets driven by a 1e6 Msun central mass BH following the disruption of sun-like star.  Model can explain the X-ray light curve without invoking a rarely-occuring deep encounter.  ....  [basically, what they saw was not unusual]


1205.1511
A survey of molecular gas in luminous sub-millimetere galaxies
Bothwell, Smail, Chapman, Genzel, ... et al


Survey for 12CO emission in 40 luminous SMGs with 850um fluxes of S850 = 4-20 mJy, conducted with the Plateau de Bure Interferometer.  Detect 12CO emission in 32 SMGs at z~1.2-4.1.  Devie median spectral line energy distribution for luminous SMGs and estimate median bass mass of 4e10 Msun.  Discovery of fundamental relationship between 12CO FWHM and 12CO line luminosity in high-z starbursts, which is interpreted as a natural consequence of the baryon-dominated dynamics within the regions probed by observations.  Use FIR luminosities to assess the star-formation efficiency in SMGs, finding a steepening of the L'CO-LFIR relation as a function of increasing 12CO J_up transition.  Derive dynamical masses and molecular gas masses, and use them for z-evolution of gas content of SMGs; find that they are not more gas rich than less vigorously SF galaxies at high-z.  Use X-ray to study correlation of AGN activity and SMBH mass with gas and dynamical properties of SMGs: find SMGs lie significantly below the local M_B-sigma relation.  Conclude that SMGs represent a class of massive, gas-rich ULG with somewhat heterogeneous properties, ranging from star bursting disk-like systems with L~1e12 Lsun, to the most highly star-forming mergers in the universe.


1205.1512
Large-scale structure with gravitational waves I: galaxy clustering
Jeong, Schmidt


A gravitational wave background can in principle be probed through clustering statistics of large-scale structure.  Calculate observed angular clustering of galaxies in the presence of GW BG at linear order, including all relativistic effects.  For a scale-invariant spectrum of gravitational waves, the effects are most significant at the smallest multipoles (2 <= l <= 5), but typically suppressed by six or more orders of magnitude with respect to scalar contributions for currently allowed amplitudes of the inflationary gravitational wave background.  [why suppressed?]  Discuss the most relevant second-order terms, corresponding to the distortion of tracer correlation functions by gravitational waves.  


1205.1514
Large-scale structure with gravitational waves II: shear
Schmidt, Jeong


The B-mode of correlation of galaxy ellipiticties (shear) can be used to detect a stochastic gravitational wave background, such as that predicted by inflation.  Derive the tensor mode contributions to shear from both gravitational lensing and intrinsic alignments, using the gauge-invariant, full-sky results of 1204.3625.  Find that the intrinsic alignment contribution, calculated using the in ear alignment model, is larger than the lensing contribution by an order of magnitude or mre, if the alignment strength for tensor modes is of the same orders for scalar modes.  This contribution also extends to higher multipoles.  [IA stronger than GW signal.]  These results make the prospects for probing tensor modes using galaxy surveys less pessimistic than previously thought, though still very challenging.


1205.1537
Self-gravitating equilibrium models of dwarf galaxies and the minimum mass for star formation
Vorobyov, Recchi, Hensler


Construct a series of model galaxies in rotational equilibrium consisting of gas, stars, ad nixed DM halo: study how these equilibrium systems depend on the mass and form of the DM halo, gas temperature, non-thermal and rotation support against gravity, and also on the redshift of galaxy formation.  Find a minimum gas mass for SF to happen.  Aim: construct realistic initial models of dwarf galaxies (take into account gas self-gravity; basis for dynamical and chemical evolution of DGs).  Find: for a given M_DM the value of M_g^min depends crucially on the gas temperature T_g, gas spin parameter \alpha, degree of non-thermal support \sigma_eff, and somewhat on the redshift for galaxy formation z_gf.  Depending on the actual values of these parameters, model galaxies may have M_g^min that are either greater or smaller than M_b.  Galaxies with M_DM >~ 1e9 Msun are usually characterized by M_g^min <~M_b, implying that SF in such objects is a natural outcome as the required bass mass is consistent with what is available according to the LCDM theory.  On the other hand, models with M_DM <~ 1e9 Msun are often characterized by M_g^min >> M_b, implying that they need more gas than available to achieve a state in which SF is allowed.


1205.1543
Observing the first galaxies
Dunlop


Overview of current knowledge of high-z galaxies (z>5).  Techniques for discovery; two that has high yields (Lyman-break and Lyman-alpha selection).  Sample selection for 5<z<8 objects, completeness and contamination; erroneous reports.  Overview of current knowledge of evolving UV continuum and Lya galaxy luminosity functions at z~5-8; discuss what can be learned from exploring the relationship between the Ly-break and ly-a selected populations.  Summparize physical properties of these galaxies in the young universe, cosmic history of star formation, reionization of the universe.  Conclude with a brief summary of the exciting prospects for further progress in this field.  This chapter can be used as an introduction to the observational study of high-z galaxies, and some review of latest results.


1205.1547
Extending the galaxy intrinsic alignment self-calibration to the GII cross-correlation
Troxel, Ishak


Extend the 3-pt intrinsic alignment self-calibration technique to the GII bispectrum.  Allow measurement and removal of GII IA contamination from the X-corr of WL signal.  GII persists in adjacent photo-z bins and must be accounted for and removed from the lensing signal.  Relate the GII and gII bispectra through the use of galaxy bias, and develop the estimator necessary to isolate the gII bispectrum from observations.  Find that the GII self-calibration technique performs at a level comparable to that of the GGI self-calibration technique, with measurement error introduced through the gII estimator generally negligible when compared to minimum survey error.  The accuracy of the relationship between the GII and gII bispectra typically allows the GII self-calibratiin to reduce the GII contamination by a factor of10 or more for all adjacent photo-z bin combinations at l>300.  For larger scales, find that the GII contamination can be reduced by a factor of 3-5 or more.  The GII self-calibration technique is complementary to the existing GGI self-caoibration technique, which together will allow the total intrinsic alignment X-corr signal in 3-pt WL to be measured and removed.


1205.1588
Environmental dependence of galaxy merger rate in {\Lambda}CDM universe
Jian, Lin, Chiueh


Use 4 different SAMs to create 4 galaxy catalogs from Millennium, to study the environmental effects and model dependence of galaxy merger rate.  Find galaxy merger rate Fmg shows strong dependence on the local overdensiiy and the dependence is similar at all redshifts. Difference in merger rates can be 4 to 20 between low and high density regions.  


1205.1785
Early-type galaxies at z=1.3. I. The Lynx supercluster: cluster and groups at z=1.3.  Morphology ad color-magnitude relation
Mei, Stanford, .... Finoguenov, ... et al


Finding early-type galaxies in groups.

Day 254

Tuesday.  Morning astro-ph reading.  Look!  Edo voted on voxcharta.  Made French Toast for breakfast--bit too much salt, need honey!  But butter is always good.  Now my strawberry-and-yogurt tastes bland.
Wednesday.  German taxes are so fun to read about, I forgot to read astro-ph last night.


1205.1057
Discovery of super-Li rich red giants in dwarf spheroidal galaxies
Kirby, Fu, Guhathakurta, Deng


Stars destroy Li in their normal evolution, and the convective envelopes of evolved red giants reach temperatures of few 1e6 K, hot enough for the 7Li(p,alpha)4He reaction to burn Li efficiently.  Only about 1% of the first-ascenet red giants more luminous than the luminosity function bump in the red giant branch exhibit A(Li) > 1.5.  Nonethless, Li-rich red giants do exist--found 15 Li-rich red giants (14 new) among a sample of 2054 in MW dwarf satellite galaxies.  Doubles the sample of metal-poor [Fe/H]<~-0.7, Li-rich red giants, includes the most metal-poor Li-enhanced star known ([Fe/H]=-2.82, A(Li)_NLTE=3.15).  Most of these stars have Li abundances larger than the universe's primordial value, the Li in these stars must have been created rather than saved from destruction.  The Li-rich stars appear like other stars in the same galaxies in every measurable regard other than Li abundance.  Consider the possibility that Li enrichment is a universal phase of evolution that affects all stars, and seems rare only because it is brief.


1205.01058
A false positive for ocean glint on exoplanets: the latitude-albedo effect
Cowan, Abbot, Voigt


Can we ID liquid water on planet surfaces?  Specular reflection (glint) increases the apparent albedo of a planet at crescent phases, but simulated reflected light curves show that glint-like phase variations can appear even if there is no specular reflection in the model.  (1) poles are likely covered by highly reflective snow and ice, (2) reflected light from a modest-obliquity planet at crescent phases probes higher latitudes than at gibbous phases (a planet's apparent albedo will naturally increase at crescent phase.  The "latitude-albedo effect" will operate even for large obliquities.  A necessary pre-condition for properly interpreting reflected phase variations: Using rotational and orbital color variations to map the surfaces of directly imaged planets and estimate their obliquity.  This effect severely limits the utility of specular reflection for detecting oceans on exoplanets.


1205.1059
Chaotic exchange of solid material between planetary systems: implications for lithopanspermia
Belbruno, Moro-Martin, Malhotra, Savransky


Examine a low energy mechanism for the transfer of meteoroids between two planetary systems embedded in a star cluster using quasi-parabolic orbits of minimal energy. ... Estimate that the order of 3e8 x l(km) could potentially be life-bearing, where l(km) is the depth of the Earth crust in km that was ejected as the result of the early bombardment.


1205.1064
The COSMOS Density Field: A reconstruction using both weak lensing and galaxy distributions
Amara, Lilly, Kovac, Rhodes, Massey, ... et al


Use HST WL measurements with galaxy clustering to reconstruct mass distribution to z=1 in COSMOS field.  High resolution in z with galaxies (with spectra); lensing data empirically calibrates mass normalization.  Two steps to convert galaxy survey into a density field: first, create a smooth field from the galaxy positions (use: i. gaussian smoothing, ii. convolution with truncated isothermal sphere, iii. fifth nearest neighbor smoothing and iv. a multi-scale entropy method).  The second step is toe rescale this density field using a bias prescription.  Calculate optimal bias scaling for each method by comparing predictions from the smoothed density field with the measured weak lensing data, on a galaxy-by-galaxy basis.  Find the bias to be 2.5 pm 0.25.  Also find evidence for a strongly evolving bias, increasing by a factor of ~3.5 between 0<z<0.8.  Strong evolution can be explained by the fact that we use a flux limited sample to build the density field.


1205.1066
Detection of ongoing star formation at low levels in nearby elliptical galaxies
Ford, Bregman


Small amounts of star formation in elliptical galaxies (seen in optical line incidies, cooling x-ray gas, and mid-IR dust emission) have been difficult to detect, but using HST WFC3 imaging, have identified individual young stars and star clusters in 4 nearby ellipticials.  Orders of magnitude more sensitive than other methods (SF of 1e-5 Msun/yr); SF detected in all galaxies.  Observe 2-8e-5 Msun/yr.  SFH roughly constant from 0.5-1.5 Gyr, but decreased by a factor of several in the past 0.3 Gyr.  Most star clusters have a mass of 1e2 to 1e4 Msun.  sSFR of 1e-16 (today) or 1e-14 (average of the past Gyr) cannot build stellar mass of galaxies within the age of the universe, quantifying for the first time the level of quenching they have experienced relative to their average value.  No obvious correlation between either the presence or spatial distribution of postulated SF indicators and the SF detected.


1205.1082
Detection of a radio bridge in Abell 3667
Carretti, Brown, ... et al


Detection of a radio bridge of unpolarized synchrotron emission connecting the NW relic of the galaxy cluster Abell 3667 to its central regions.  Emission further aligned with a diffuse X-ray bridge, and represents the most compelling direct evidence for an association between intracluster medium turbulence and diffuse synchrotron emission.  Conclude: synchrotron bridge is related to the post-shock turbulence wake trailing a shock front.  The origin of the relativistic electrons still unknown; the turbulent re-acceleration model provides a natural explanation for the large-scale emission.  The bridge magnetic field intensity is 0.5-0.6 uG.  Further detect diffuse emission coincident with the central regions of the cluster for the first time.


1205.1124
Swift follow-up observations of candidate gravitational-wave transient events
Evans, et al (>800 authors!)


Present the first multi-wavelength follow-up observations of two candidate gravitational-wave transient events recorded by LIGO and Virgo in 2009-2010 science run.  Events detected were observed by Swift.  Image transient detection used (but consistent with BG).  Selected GW events show no evidence of an astrophysical origin; one of them consistent with BG and the other was a test (part of a "challenge").  Demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement going EM and GW observations could bring. ...  [bah, boring!  no real results]


1205.1194
Galactic annihilation emission from nucleosynthesis positrons
Martin, Strong, Jean, Alexis, Diehl


The Galaxy hosts a widespread population of low-energy positrons, as seen in gamma-ray telescopes through annihilation emission from the bulge region, with a fainter contribution from the inner disk.  Exact origin of these particles currently unknown.  Estimate the contribution to the annihilation signal of positrons generated in the decay of radioactive 26Al, 56Ni and 44Ti.  Adapt GALPROP propagation code to simulate the transport and annihilation of radioactivity positron in a model of our Galaxy.  Using plausible source spatial distributions, explore several possible propagation scenarios to account for the large uncertainties in the transport of 1MeV positrons in the ISM.  In high-diffusion ballistic case, up to 40% escape the Galaxy.  This affects bulge positrons more than disk positrons (disk positrons mostly injected in the dense molecular ring.  Nucleosynthesis positrons alone cannot account for the observed annihilation emission in the frame of the model.  Additional component is needed to eeelain the strong bulge contribution, and the latter is very likely concentrated in the central regions if positrons have initial energy in the 100keV-1MeV range.


1205.1332
Low Metallicity ISM: excess submillimetre emission and CO-free H2 gas
Madden et al


Excess emission often found in low metallicity ISM of dwarfs in FIR/submm regions than the more metal-rich galaxies.  Excess found beginning or beyond 500mu.  The SEDs of the lowest meatllicity galaxies give very low dust masses and excessively low values of dust to gas ratio (DGR), inconsistent with the amount of metals expected to be captured into dust.  These results rely on accurately quantifying the total molecular gas reservoir, which is uncertain in low metallicity galaxies due to the difficulty in detecting CO(1-0) emission.  Dwarf galaxies show an exceptionally high CII/CO(1-0) ratio which may be indicative of a significant reservoir of 'CO-free' molecular gas residing in the pohotodissociated envelope, and not traced by the small CO cores.


1205.1401
Composite reverberation mapping
Fine, Shanks, Croom, Green, Kelly, Berge, Chornock, Burgett, Magnier, Price


Reverberation mapping: one of the best techniques for studying the inner regions of QSOs.  Besed on cross-correlating continuum and emission-line light curves.  New time-resolved optical surveys will produce well sampled light curves for many thousands of QSOs.  Explore the potential of stacking samples to produce composite cross-correlations for groups of objects that have well sampled continuum light curves, but only a few (~2) emission-line measurements.  Explores multiplexing capability of multi-object spectrographs to significantly reduce the observational expense of revelation mapping, in particular at high redshift (0.5 to 2.5).  Demonstrate the technique using simulated QSO light curves (biases from stacking studied).  Show: stacked X-corr have smaller amplitude peaks compared to well sampled correlation functions as the mean flux of the emission light curve is poorly constrained.  But the position of the peak remains intact.  ....


1205.1493
Intensity mapping of lyman-alpha emission during the epoch of reionization
Silva, Santos, Gong, Cooray


Absolute intensity and anisotropies of Lya field present during the epoch of reionization.  Consider both galaxy and IGM emission, take into account all of the contributions to the production of Lya photons: recombinations, collisions, continuum emission from stars and scattering of Lyman-n photons in the IGM.  Find emission from individual galaxies dominates over the IGM (at z~7-10), a level well below the extragalactic BG intensity from starlight emission from galaxies; unlikely that the Lya background during reionization can be established by an experiment aiming at an absolute BG light measurement.  Instead consider Lya intensity mapping for anisotropy power spectrum measurements.  a few Mpc scale fluctuations can be measured.