Day 371

Thursday, still behind.  Friday.
1301.3131
Explaining the observed velocity dispersion of dwarf galaxies by baryonic mass loss during the first collapse
Gritschneder, Lin

Dwarf galaxies are the building blocks of larger galaxies, formed relatively early (when BG density was high); they are expected to retain their integrity as satellite galaxies when they merge to form larger entities.  Many dSphs are found in the galactic halo around the MW, but their phase space density (velocity dispersion) appears to be significantly smaller than that expected for satellite dwarf galaxies in the LCDM scenario.  In order to account for this discrepancy, consider the possibility that they may have lost a significant fraction of their baryonic matter content during the first infall at the Hubble expansion turnaround.  Such ass loss arises naturally due to the feedback by relatively massive stars which formed in their centers briefly before the maximum contraction.  Show with N-body sims that the timely loss of a significant fraction of the dSphs initial baryonic matter content can have profound effects on their asymptotic half-mass radius, velocity dispersion, phase-space density, and the mass fraction between residual baryonic and dark matter.

1301.3132
Relativistic effects in galaxy clustering in a parameterized post-Friedmann universe
Lombriser, Yoo, Koyama

Signatures of quintessence and modified gravity theories in galaxy clustering within a parameterized post-Friedmann framework.  Effects in the linear Post-Friedmann perturbations,; relativistic effects in galaxy clustering.  Quantify the impact of modified gravity and DE models on galaxy clustering from velocity-to-matter density ratio F, the velocity contribution R, and the potential contribution P; give an estimate of their detectability in future galaxy surveys.  The relativistic correction contains additional information on gravity and DE which needs to be taken in to account in consistent horizon-scale tests of departures from LCDM using the galaxy-density field.

1301.3157
Mass assembly in quiescent and star-forming galaxies since z=4 from UltraVISTA
Ilbert, McCracken, Le Fevre, Capak, ... Mellier et al

Estimate galaxy stellar mass function and stellar mass density for SF and quiescent galaxies with 0.2<z<4, using 30-band photos.  220k galaxies UltraVISTA DR1.  Compare with 10.8k specs from zCOSMOS, pretty good precision.  Derive stellar mass function and correct for the Eddington bias; find mass-dependent evolution of the global and SF populations, with the low-mass end of the mass functions evolving more rapidly than the high-mass end.  THis mass-dependent evolution is a direct consequence of the SF being "quenched" in galaxies more massive than M>1e10.8 Msun, while the rapid evolution at the low mass end is explained by the evolution of the specific SFR.  By deriving the global stelar mass density, show that galaxies grow in mass twice as quickly at 1<z<4 than at 0.1<z<1.  Also confirm that global stellar mass density is lower by 0.2-0.3 dex than the cosmic SFR integrated over cosmic time [why would that be?].  For the mass function of the quiescent galaxies, do not find any significant evolution of the high-mass end at z<1, while observing a clear flattening of the faint-end slope.  From z=3 to z=1, the density of quiescent galaxies increase over the entire mass range.  Their comoving stellar mass density increases by 1.5 between z=3 and z=1 and by less than 0.2 dex at z<1.  Finally, compare results with the semi-analytical model and find that they overestimate the density of low mass quiescent galaxies by an order of magnitude.

1301.3164
SYNMAG photometry: a fast tool for catalog-level matched colors of extended sources
Bundy, Hogg, et al

Aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data.  Code public.  

1301.3255
Nonlinearities in modified gravity cosmology.  II.  impacts of modified gravity on the halo properties
Zhang, et al

DM halos essential in understanding NL evolution.  Use N-body sims to see modified gravity effects on halo mass function, concentration and bias; model the impact of mod. grab. by a single parameter zeta, which determines the enhancement of particle acceleration wrt GR.  Results demonstrate that the halo mass function and/or the concentration are snesitive to the nature of gravity.

1301.3301
Evolution of hierarchical clustering in the CFHTLS-Wide since z~1
Wolk, McCracken, ... Kilbinger, Mellier, Ilbert, et al

Measurements of higher order clustering of galaxies from CFHTLS Wide survey.  0.2<z<1, volume limited, over the 4 independent fields of CFHTLS; use counts-in-cells to measure variance and hierarchical moments as a function of z and angular scale.  Test for robustness, field-to-field scatter in good agreement with analytical predictions.  Suggest hierarchical moments increase with z.  At large scales, measurements are fully consistent with perturbation theory predictions for standard LCDM with simple linear bias.

1301.3456
Fitting methods for Baryon Acoustic Oscillations in the Lyman-{\alpha} forest fluctuations in BOSS data release 9
Kirkby, Margala, Slosar, et al

Describe fitting methods developed to analyze fluctuations in Ly-a forest for BAO measurements.  Based on models of 3d correlation function in physical coordinate space; includes effects of z-space distortions, anisotropic NL broadening, broadband distortions.  Allow for independent scale factors along and perpendicular to the LoS to minimize dependence on assumed fiducial cosmology, and to obtain separate measurements of the BAO angular and relative velocity scales.  Fitting software and the input files to reproduce results publicly available.

1301.3459
Measurement of Baryon Acoustic Oscillations in the Lyman-alpha forest fluctuations in BOSS data release 9
Slosar, Irsic, Kirkby, Bailey, ... et al

Measure the position of BAO feature in Ly-a forest at z=2.4.  Assess bias in method, stability of the error covariance matrix and possible systematic effects.  Errors become significantly non-G for deviations over 3 std dev from best fit value.  Give tighter constraints than previous BAO analysis, providing a consistency test of the std cosmological model in a new z regime.

Day 370

Saturday.  Need to catch up for about 4 days worth, in the next 2 days.  Actually, Monday.

1301.2596
Obscured star formation in Ly-alpha blobs at z=3.1
Tamura et al

Results suggest that LABs on average have little ultra-luminous obscured star-formation, in contrast to a long-believed picture that LABs undergo an intense episode of dusty SF activities with SFR of 1e3 Msun/yr.  Observations with ALMA are needed to directly study the obscured part of SF activity in the LABs.

1301.2670
What's up in the Milky Way?  The orientation of the disc relative to the triaxial halo
Debattista, ... Moore, et al

Models of Sag Stream consistently find that MW disc is oriented such that its symmetry axis is along the intermediate axis of the triaxial DM halo.  Attempt to build models of disc galaxies in such an orientation.  First 2/3 models: rigidly grow a disc in a triaxial halo such that the disc ends up perpendicular to the intermediate axis.  Also attempt to coax a disc to form in an intermediate-axis orientation by producing a gas+dark matter triaxial system with gas angular momentum about the intermediate axis.  In all cases fail to produce systems which remain with stellar angular momentum aligned with the halo's intermediate axis.  For one of these unstable simulations, show that the potential is even rounder than the models of MW potential in the region probed by Sagittarius Stream.  Conclude that the MW disc is very unlikely to be in an intermediate axis orientation.  Find that a disc can persist off one of the principal planes of the potential.  Propose that the disc of MW must be tilted relative to the principal axis of DM halo.  Direct confirmation of this prediction would constitute a critical test of MOND.

1301.2685
Confronting predictions of the galaxy stellar mass function with observations at high-redshift
Wilkins et al

Galaxy stellar mass function evolution at z>=5 using large cosmo hydro sims.  Observational determinations of galaxy stellar mass function at very-high z typically assume a relation between the observed UV luminosity and stellar M/L ratio, which is applied to high-z samples in order to estimate stellar masses; this relation can be measured from the simulations.  Find 2 significant differences with the usual observational assumption: It evolves strongly with z and has a different shape.  Using this relation to make a consistent comparison between galaxy stellar mass functions, find that at z=6 and above, the simulation predictions arei n good agreement with observed data over the whole mass range.  Without using the correct UV luminosity and stellar M/L ratio, the discrepancy would be up to 2 orders of mag for galaxies >1e10 Msun/h.  At z=5, however, th stellar mass function for low mass < 1e9 Msun/h galaxies is overpredicted by a factor of few, consistent with the behaviour of the UV LF, and perhaps a sign that feedback in the simulation is not efficient enough for these galaxies.

1301.2744
Structure of dark matter haloes in warm dark matter models and in models with long-lived charged massive particles
Kamada, et al

Study the formation of NL structure in WDM models and in a Long-Lived Charged Massive Particle (CHAMP) model.  CHAMPs with a decay lifetime of ~1yr induce characteristic suppression in the matter power spectrum at subgalactic scales through acoustic oscillations in the thermal background.  ... such models resolve the so-called "missing satellite problem".

1301.3010
A new method to improve photometric redshift reconstruction.  Applications to the Large Synoptic Survey Telescope
Gorecki et al

Use magnitude to apply priors for catastrophic outliers.  Try combining template and neural network methods.  Conclude that the photometric redshifts will be accurately estimated with the LSST if a Bayesian prior probability and a calibration sample are used.

1301.3069
New organizations to support astroinformatics and astrostatistics
Feigelson, Ivezic, Hilbe, Borne

Share info.  As the title says.

1301.3092
AGN-driven quenching of star formation: morphological and dynamical implications for early-type galaxies
Dubois, Gavazzi, Peirani, Silk

To understand the physical mechanisms during the formation of massive early-type galaxies, perform 6 zoomed hydro cosmo sims of halos of 4.3e12<(M_vir/Msun)<8.0e13 at z=0, using RAMSES (Adaptive Mesh Refinement code).  Explore the role of AGN, through jets powered by the accretion onto SMBH on the formation of massive elliptical galaxies.  In the absence of AGN feedback, large amounts of stars accumulate in the central galaxies to form overly massive, blue, compact and rotation-dominated galaxies.  Powerful AGN jets transform the central galaxies into red extended and dispersion-dominated galaxies.  This morphological transformation is driven by the efficient quenching of the in situ SF due to AGN feedback, which transform these galaxies into systems built up by accretion.  For such galaxies, the proportion of stars deposited farther away from the center increases, and galaxies have larger sizes.  The accretion is also directly responsible for randomizing the stellar orbits, increasing the amount of dispersion over rotation of stars as a function of time.  Find that the galaxies with AGN feedback better match the observed scaling laws, such as the size-mass, velocity dispersion-mass, fundamental plane relations, and slope of the total density profiles at z~0, from dynamical and strong lensing constraints.

Day 369

Monday.

1301.2328
Molecular gas and star formation in nearby disk galaxies
Leroy et al

Compare molecular gas traced by 12CO(2-1) maps from HERACLES survey with tracers of the recent SFR across 30 nearby disk galaxies.  Demonstrate first-order linear correspondence between Sig_mol and Sig_SFR but also find important second-order systematic variations in the apparent molecular gas depletion time, t_dep(mol) = Sig_mol/Sig_SFR. At 1kpc resolution, CO correlates closely with may tracers of the recent SFR.  Weighting each line of sight equally and using a fixed, MW alpha_CO, data yield a molecular gas depletion time ~ 2.2 Gyr with 0.3 dex scatter, in good agreement with literature data [what are the other lit. data based on?].  Apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and molecular gas surface density and find N=1pm0.15 for the full dataset (some variation for individual galaxies).  Caution that a power law treatment oversimplifies the topic.  The strongest of the simplifications are a decreased t_dep(mol) in low-mass, low-metallicity galaxies and a correlation of the kpc-scale t_dep(mol) with dust-to-gas ratio, D/G.  These correlations can be explained by a CO-to-H2 conversion factor that depends on D/G in the theoretically expected way.  After applying a D/G-dependent alpha_CO, some weak correlations between t_dep(mol) and local conditions persist.  In particular, observe lower t_dep(mol) and enhanced CO excitation associated with some nuclear gas concentrations.  These appear to reflect real enhancements in the SFR/H2 and t_dep appears multivalues at fixed Sig_mol, supporting the idea of "disk" and "SB" modes driven by environmental factors.

1301.2330
The velocity function of dark matter haloes at r=20 kpc: Remarkably little evolution since z~4
Weinmann, Franx, Dokkum, Brezanson

In the Millennium-II simulation.  As the title says.  Analyze the histories of the main progenitors of haloes, and find that the DM distribution within the central 20 kpc of massive halos has been in place since early times.  This provides evidence for the inside-out growth of haloes.  The constance of the central circular velocity of haloes may offer a natrual explanation for the observational finding that the galaxy circular velocity is an excellent predictor of various galaxy properties.  Results also indicate that we can expect a significant number of galaxies with high circular velocities already at z=4.  Finally, adding baryonic mass and using a simple model for halo adiabatic contraction, find remarkable agreement with the velocity dispersion functions inferred observationally by Bezanson+2011 up to z~1 and down to about 220 km/s.

1301.2338
HST proper motions of stars within globular clusters
Bellini, van der Marel, Anderson

HST is an excellent astrometric tool: diffraction-limited resolution allows measurements of positions and fluxes for stars all the way to the center of most globular clusters.  Apart from small changes due to breathing, its PSFs and geometric distortion have been extremely stable over its 20-year lifetime.  Now >20 globular clusters for which there exist two or more well-separated epochs in the archive, spanning up to 10+ years.  Photometric and astrometric techniques have allowed measurements of 10s of 1000s of stars per cluster within 1" from the center, with typical proper-motion errors of ~0.02 mas/yr, which translates to 0.8 km/s for a typical cluster.  THese high-quality measurements can be used to detect the possible presence of a central intermediate-mass BH and put constraints on its mass.  In addition, they will provide a direct measurement of the cluster anisotropy and equipartition.  Present preliminary results from this project, and discuss them in the context of what is already known from other techniques.

1301.2576
Decomposing CMB lensing power with simulation
Anderes

Reconstruction of CMB lensing potential is based on a Taylor expansion of lensing effects which is known to have poor convergence properties.  For lensing of temperature fluctuations, an understanding of the higher order terms in this expansion accurate enough for current experimental sensitivity levels has been developed in Hanson+2010, as well as a slightly modified Okamoto+Hu quadratic estimator which incorporates lensed rather than unlensed spectra into the estimator weights to mitigate the effect of higher order terms.  Extend these results in several ways: (1) generalize this analysis to the full set of quadratic temperature/polarization lensing estimators, (2) study the effect of higher order terms for more futuristic experimental noise levels, (3) show that the ability of the modified quadratic estimator to mitigate the effect of higher order terms relies on a delicate cancellation which occurs only when the true lensed spectra are known.  Investigate the sensitivity of this cancellation to uncertainties in or knowledge of these spectra.  Find that higher order terms in the Taylor expansion can impact projected error bars at experimental sensitivities similar to those found in future ACTpol/SPTpol experiments.

Day 368

Wednesday.  Thursday.  Sunday.

1301.1348
Reconstructing the initial density field of the local universe: method and test with mock catalogs
Wang, Mo, Yang, van den Bosch

Reconstruct an initial linear density field which follows the multivariate Gaussian distribution with variances given by the linear power spectrum of the current CDM model and evolves through gravitational instability to the present-day density field in the local Universe.  Develop a Hamiltonian Markov Chain Monte Carlo (HMC) method to obtain the linear density field from a posterior probability function that consists of 2 components: a prior of a Gaussian density field with a given linear spectrum, and a likelihood term that is given by the current density field.  The present-day density field can be reconstructed from galaxy groups using the method developed in Wang+(2009).  Using a realistic mock SDSS DR7 based on Millennium sim with galaxies, show that this method can effectively and accurately recover both the amplitudes and phases of the initial, linear density field down to a scale of 2.8 Mpc/h.  To examine the performance of this method in the highly NL regime, use N-body sims to evolve these reconstructed IC to the present day.  The resimulatd density field thus obtained accurately matches the original density field of the Millennium simulation in the density range 0.3<rho/rho(mean)<20 without any significant bias.  The Fourier phases of the resimulated density fields are tightly correlated with those of the original simulations down to a scale corresponding to a wavenumber of ~1 h/Mpc, much smaller than the translinear scale, which corresponds to a wavenumber of 0.15 h/Mpc.

1301.1474
Influence of the variation of fundamental constants on the primordial nucleosynthesis
Coc et al

The main influences come from the weak rates and the A=2, n(p,g)d, bottleneck reaction.

1301.1682
The relation between velocity dispersion and mass in simulated clusters of galaxies: dependence on the tracer and the baryonic physics
Munari, Biviano, Borgani, Murante, Fabjan

Present an analysis of the relation between the masses of cluster- and group-sized haloes, extracted from LCDM cosmological N-body and hydrodynamic simulations, and their velocity dispersions, at different redshifts from z=2 to z=0.  The main purpose of this analysis: understand how the implementation of baryonic physics in simulations affects such relation, i.e., to what extent the use of the velocity dispersion as a proxy for cluster mass determination is hampered by the imperfect knowledge of the baryonic physics.  Use several sets of simulations with different physics implemented.  Velocity dispersions are determined using 3 different tracers: DM particles, sub haloes, and galaxies.  Confirm that DM particles trace a relation that is fully consistent with the theoretical expectations based on the virial theorem and with previous results presented in the literature.  Subhaloes and galaxies tracer steeper relations, and with larger values of the normalization.  Such relations imply that galaxies and subhaloes have a ~10 per cent velocity bias relative to the DM particles, which can be either positive or negative, depending on the halo mass, redshift and physics implemented in the simulation.  Explain these differences as due to dynamical processes, namely dynamical friction and tidal disruption, acting on substructures and galaxies, but not on DM particles.  These processes appear to be more or less effective, depending on the halo masses and the importance of baryon cooling, and may create a non-trivial dependence of the velocity bias and the D-M relation [?] on the tracer, the halo mass and its redshift.  These results are relevant in view of the application of velocity dispersion as a proxy for cluster masses in ongoing and future large redshift surveys.

1301.1684
Testing phenomenological and theoretical models of dark meter density profiles with galaxy clusters
Silva, Lima, Sodre

Use the stacked gravitational lensing mass profile of 4 high-mass (M>1e15 Msun) galaxy clusters around z~0.3 from Umetsu+ 2011 to fit density profiles of phenomenological (NFW, Einasto, Sersic, Stadel and Hernquist) and theoretical (non-singular isothermal sphere, DARKexp, Kang & He) models of the DM distribution.  Account for large-scale structure effects, including a 2-halo term in the analysis.  Find that the Stadel model provides the best fit to the data as measured by the reduced chisq.  It is followed by the generalized NFW profile with a free inner slope and by the Einasto profile.  The NFW model gives the best fit if the 2-halo term is neglected; in agreement with results from Umetsu.  Among the theoretical profiles, the DARKexp model with a single form parameter has the best performance, almost identical to that of the Stadel profile.  This may indicate a connection between this theoretical model and the phenomenology of dark matter haloes, shedding light on the dynamical basis of empirical profiles which emerge from numerical simulations.  
1301.0624
The X-ray/SZ view of the virial region.  II.  Gas mass fraction
Eckert, Ettori, Molendi, Vazza, Paltani

Using hot gas fraction of galaxy clusters as standard ruler relies on the assumption that the baryon fraction in clusters agrees with the cosmic value, and does not differ from one system to another.  Test this hypothesis by measuring the gas mass fraction over the entire cluster volume in a sample of local clusters.  Combining the SZ thermal pressure from Planck and the X-ray gas density from ROSAT, measure for the first time the average gas fraction out to the virial radius and beyond in a large sample of clusters.  Also obtain azimuthally-averaged measurements of the gas fraction for 18 individual systems, which were used to compute the scatter of f_gas around the mean value at different radii and its dependence on the cluster's temperature.  THe gas mass fraction increases with radius and reaches the cosmic baryon fraction close to R200.  At R200, measure f_gas,200 = 0.176pm0.009.  Find significant differences between the baryon fraction of relaxed, CC systems and unrelaxed, non-cool core (NCC) clusters in the outer regions.  On average, the gas fraction in NCC clusters slightly exceeds the cosmic baryon fraction, while in CC systems the gas fraction converges to the expected value when accounting for the stellar content, without any evidence for variations from one system to another.  Find that f_gas estimates in NCC systems slightly disagree with the cosmic value approaching R200.  This result could be explained either by a violation of the assumption of hydrostatic equilibrium or bay an inhomogeneous distribution of the gas mass.  Conversely, CC clusters are found to provide reliable constraints on f_gas at overdensities >200, which makes them suitable for cosmological studies.

1301.1688
PRIMUS: constraints on star formation quenching and galaxy merging, and the evolution of the stellar mass function from z=0-1
Moustakas, Coil, Aird, Blanton, Cool, Eisenstein, ... et al

Measure the evolution of the stellar mass function (SMF) of 0<z<1 using PRIMUS and SDSS.  From PRIMUS construct an i<23 flux-liited sample of 40 galaxies at 0.2<z<1.0 over 5 fields totaling 5.5 degsq, and from SDSS select 170k galaxies at 0.01<z<0.2 that are analyzed consistently wrt PRIMUS to minimize systematic errors in evolutionary measurements.  Find that the SMF of all galaxies evolves relatively little since z=1, although there is evidence for mass assembly downsizing; measure a ~30% increase in the number density of 1e10 Msun galaxies since z~0.6, and a <10% change in the number density of all >1e11 Msun galaxies since z~1.  Dividing the sample into SF and quiescent using an evolving cut in specific SFR, find that the number density of ~1e10Msun SF galaxies stays relatively constant since z~0.6, whereas the space-density of >1e11 Msun SF galaxies decreases by ~50% in 0<z<1.  Meanwhile, the number density of ~1e10Msun quiescent galaxies increases steeply towards low redshift, by a factor of ~2-3 since z~0.6, while the number of massive quiescent galaxies remains approximately constant since z~1.  These results suggest that the rate at which SF galaxies are quenched increases with decreasing stellar mass, but taht the bulk of the stellar mass buildup within the quiescent population occurs around 1e10.8Msun.  In addition, conclude that mergers do not appear to be a dominant channel for the stellar mass buildup of galaxies at z<1, even among massive (1e11 Msun) quiescent galaxies.

1301.1863
CFHTLenS: Higher-order galaxy-mass correlations probed by galaxy-galaxy-galaxy lensing
Simon, Erben, Schneider, Heymans, Hildebrandt, Hoekstra, Kitching, Mellier, Van Waerbeke, ... Kuijken, Rowe, Schrabback, Semboloni, Velander et al

First direct measurement of the galaxy-matter bispectrum as a function galaxy luminosity, stellar mass, and SED type.  Use G3L technique on angular scales between 9 and 50 arcmin, to quantify (i) the excess surface mass density around galaxy pairs ("excess mass"), (ii) the excess shear-shear correlations around single galaxies, both of which yield a measure of two types of galaxy-matter bispectra.  Apply method to the state-of-theart CFHTLenS, spanning 154 sq.deg.  This survey allows us to detect a significant change of the bispectra with lens properties.  Measurements for lens populations with distinct redshift distributions become comparable by a newly devised normalization technique.  That will also aid future comparison to other surveys or simulations.  A significant dependence of the normalized G3L statistics on luminosity within -23<M_r<-18 and stellar mass within 5e9Msun<M_star<2e11Msun is found. Both bispectra exhibit a stronger signal for more luminous lenses or higher stellar mass lenses for the excess mass.  Importantly, find the excess mass to be very sensitive to galaxy type as recently predicted with SAM: luminous (M_r<-21) late-type galaxies show no detectable signal, while all excess mass detected for luminous galaxies seems to be associated with early-type galaxies.  Also present the first observational constraints on 3rd-order stochastic galaxy biasing parameters.

1301.2009
On the abundances of noble and biologically relevant gases in lake Vostok, Antarctica
Mousis, Lakhlifi, Picaoud, Pasek, Chassefiere

Investigate the composition of clathrates (molecules trapped in crystal structure) that are expected to form in this environment from the air supplied to the lake by melting ice.  Determine the fugacities of the different volatiles present in the lake by defining a "pseudo" pure substance dissolved in water owning the average properties of the mixture and by using the Redlich-Kwong equation of state to mimic its thermodynamic behavior.  Irrespective of the clathrate structure considered in the model, find that Xe and Kr are strongly impoverished in the lake water compared to their atmospheric abundances.  Ar and CH4 are also found depleted in the Lake Vostok water by 1/2-1/3-95% ranges, compared to atmospheric abundances.  On the other hand, the CO abundance is found substantially enriched in the lake water compared to atmospheric abundance (by x1.6-x5).  The comparison of the predictions of the CO2 and CH4 mole fractions in Lake Vostok with future in situ measurements will allow disentangling between the possible supply sources.  [what is their prediction based on?  Atmospheric composition in the past?]

1301.2067
The star-forming progenitors of massive red galaxies
Cattaneo, Woo, Dekel, Faber

Link between massive red galaxies at z=0 and SF galaxies at high z investigated with SAM that is successful in explaining the galaxy color-magnitude bimodality, and the stellar mass-age relation for red-sequence galaxies.  Model used to explore the processes that drive SF in different types of galaxies as a function of stellar mass and redshift.  Find that most 2<z<4 SF galaxies with M*>1e10 Msun evolve into red-sequence galaxies.  Also, most of the massive galaxies on the red-sequence today have passed through a phase of intense SF at z>2.  Specifically, ~90% of today's red galaxies with M*>1e11 Msun were fed during this phase by cold streams including minor mergers.  Gas-rich major mergers are rare and the effects of merger-driven SB are ephemeral.  On the other hand, major mergers are important in powering the most extreme SBs.  Gas-rich mergers also explain the tail of intermediate-mass red galaxies that form relatively late, after the epoch of peak SF.  In 2/3 of the currently red galaxies that had an intense SF event at z<1, this event was triggered by a merger.

1301.2119
Modeling the history of astronomy: Ptolemy, Copernicus and Tycho
Timberlake

A series of activities in which students investigate and use the models of planetary motion introduced by Ptolemy, Copernicus, and Brahe.  The activities involve the use of open source software to help students discover important observational facts, learn from necessary vocabulary, understand the fundamental properties of different theoretical models, and relate the theoretical models to observational data.  Once they understand the observations and models, students complete a series of projects in which they observe and model a fictitious solar system with 4 planets orbiting in circles around a central star.

Day 367

Tuesday.

1301.0830
Effect of measurement errors on predicted cosmological constraints from shear peak statistics with LSST

Bard et al

The statistics of peak counts in reconstructed shear maps contain information beyond the power spectrum, and can improve cosmological constraints from measurements of the power spectrum alone if systematic errors can be controlled.  Study the effect of galaxy shape measurement errors on predicted cosmological constraints from the statistics of shear peak counts with LSST.  Use the LSST image simulator in combination with cosmological N-body simulations to model realistic shear maps for different cosmological models.  Include both galaxy shape noise and measurement errors on galaxy shapes.  Find that the measurement errors considered have little impact on the constraining power of shear peak counts for LSST.

1301.0871
Updated catalog of 132,684 galaxy clusters and evolution of brightest cluster galaxies
Wen, Han

132k clusters in 0.05<z<0.8 of SDSS DR8.  52k have spectro-z from DR9.  BCGs are more luminous in richer clusters and at higher z.

1301.0983
Growth diagnostics for dark energy models
Sampurnanand, Sen

Introduce a new set of parameters r_g, s_g involving the linear growth of matter perturbation that can be used to distinguish different DE models.  For LCDM, these parameters take exact values (1,1) at all z, but other models follow different trajectories in the r,s phase plane.  With nearly identical evolution of the linear density contrast, one can still produce distinguishable trajectories in the r,s phase plane.  It is also possible to put stringent constraint in the r,s phase plane, ruling out many possible DE behaviors.

[*]1301.1037
The Atacama cosmology telescope: temperature and gravitational lensing power spectrum measurements from three seasons of data
Das et al

Present temperature power spectra of CMB from 3 seasons of ACT at 148 and 218 GHz, as well as the cross-frequency spectrum between the two channels.  Detect and correct for contamination due to the Galactic cirrus in equatorial maps.  Present results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors quoted.  Cross-correlate ACT with SPT maps, show that they are consistent.  Measurements of higher-order peaks in the CMB power spectrum provide an additional test of the LCDM model, and help constrain extensions beyond the standard model.  The smaller angular scale power spectrum also provides constraining power on the SZ effects and extragalactic foregrounds.  Also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6 sigma detection significance.

1301.1041
Shocks, cooling and the origin of star formation rates in spiral galaxies
Bonnell, Dobbs, Smith

SF originates in the large scale dynamics of a galaxy, but occurs on the small scale of an individual SF event.  Present first numerical simulation to resolve the SF process on sub-parsec scales, while also following the dynamics of the ISM on galactic scales.  In the model, the warm low density ISM gas [from where?  within the galaxy, or outside?] flows into the spiral arms where orbit crowding produces the shock formation of dense clouds, held together temporarily by their external pressure.  Cooling allows the gas to be compressed to sufficiently high densities that local regions collapse under their own gravity and form stars.  The SFR follow a Schmidt-Kennicutt Sigma_SFR~Sigma_gas^1.4 type relation with the local surface density of gas while following a linear relation with the cold and dense gas.  Cooling is the primary driver of SF and the SFR as it determines the amount of cold gas available for gravitational collapse.  The SFR found in the simulations are offset to higher values relative to the extragalactic values, implying a constant reduction, such as from feedback or magnetic fields, is likely to be required.  Intriguingly, it appears that a spiral or other convergent shock and the accompanying thermal instability can explain how SF is triggered, generate the physical conditions of molecular clouds and explain why SFR are tightly correlated to the gas properties of galaxies.

[*]1301.1056
Mission to the Trojan Asteroids: lessons learned during a JPL planetary science summer school mission design exercise
Diniega, et al

The 2013 Planetary science decadal survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions.  Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar system.  Present a conceptual design for a mission to the Jovian Trojan asteroids: "TASTER" (Trojan ASteroid Tour, Exploration, and Rendezvous) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary science summer school.  Proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000-100 km over a 12 mo. nominal science data capture period.  Proposed instrument payload (wide/narrow angle cameras, visual and IR mapping spectrometer, neutron/gamma ray spectrometer) would provide unprecedented high-res, regional-to-global datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar system.  Although the mission design was completed as a part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies.  In particular, we identify and discuss key issues that can make large difference in the complex trade-offs required when designing a mission to the Trojan asteroids.

[*]1301.1217
Modeling color-dependent galaxy clustering in cosmological simulations
Masaki, Lin, Yoshida

Extend subhalo abundance matching (SHAM) to assign galaxy color to subhaloes.  Separate a luminosity-binned subhalo sample into 2 groups by a secondary subhalo property which is presumed to be correlated with galaxy color.  The 2 subsamples then represent red and blue galaxy populations.  Explore the two models for the secondary property; subhalo assembly time and local DM density around each subhalo.  The model predictions for the galaxy 2-pt correlation functions are compared with the recent results from the SDSS.  Show that the observed color dependence of galaxy clustering can be reproduced well by this method applied to cosmological N-body simulations without baryonic components.  Then compare the model predictions for the color-dependent galaxy-mass cross correlation functions with the results from gravitational lensing observations.  The comparison allows distinction of models, and also the discuss what subhalo property should be used to assign color to subhalos accurately.  Show that the extended abundance matching method using local DM density as a color proxy provides an accurate description of the galaxy population in the local universe.

1301.1228
New constraints on cosmic reionization from the 2012 Hubble Ultra Deep Field campaign
Robertson, ... Ellis, ... et al

To study cosmic reionization, one needs to identify and characterize the early sources of H-ionizing photons.  The UDF12 campaign has acquired the deepest IR images of the WFC3 on Hubble, and systematically explored the galaxy population deep into the era when CMB data indicates reionization was underway.  The UDF12 campaign thus provides the best constraints to date on the abundance, luminosity distribution, and spectral properties of early SF galaxies.  Synthesize the new UDF12 results with the most recent constraints from CMB observations to infer z-dependent UV luminosity density, reionization histories, and e- scattering optical depth evolution consistent with the available data.  Under reasonable assumptions about the escape fraction of hydrogen ionizing photons and the intergalactic medium clumping factor, find that to fully reionize the universe by z~6 the population of SF galaxies at z~7-9 likely must extend in luminosity below the UDF12 limits to absolute UV magnitudes of -13 or fainter.  Low levels of SF extending to z~15-25, as suggested by the normal UV colors of z~7-8 galaxies and the smooth decline in abundance with z observed by UDF12 to z~10, are additionally likely required to reproduce the optical depth to e- scattering inferred from CMB observations.

1301.0952
TASI 2012 lectures on astrophyscial probes of dark matter
Profumo

Connection between how DM was produced in the early universe, and how this can be detected today; where does the WIMP miracle come from (is it really a miracle)?  What brackets the mass range for thermal relics?  Where does <sigma v> come from, and what does it mean?  What is the difference between chemical and kinetic decoupling?  WHy do some people think that DM cannot be lighter than 40 GeV?  Why is \bar{b} b such a popular annihilation final state?  Why is antimatter a good way to look for DM?  Why should the CR positron fraction decline with energy, and why does it not?  How does one calculate the flux of neutrinos from DM annihilation in a celestial body, and when is that flux independent of the DM pair-annihilation rate?  How does DM produce photons?  What You Always Wanted to Know About Dark Matter But Were Afraid to Ask!

Day 366

Monday.  

1301.0617
The X-ray/SZ view of the virial region.  I.  Thermodynamic properties
Eckert, et al

Measure the thermodynamic properties of cluster outer regions to provide constraints on the processes that rule the formation of large scale structures.  Derive the thermodynamic properties of IC gas (T, S) by combining SZ thermal pressure from Planck and X-ray gas density from ROSAT; allows reconstruction T and S profiles out to virial radius and beyond, in a large sample of objects.  Find S rises steadily with radius, albeit at a somewhat lower rate than predicted by self-similar expectations.  Relaxed systems appear to follow the self-similar expectations more closely than perturbed objects.  Results indicate that the well-known entropy excess observed in cluster cores extends well beyond the central regions.  When correcting for the gas depletion, the observed entropy profiles agree with the prediction from gravitational collapse only, especially for cool-core clusters.

[*]1301.0620
Inside out and upside down: tracing the assembly of a simulated disk galaxy using mono-age stellar populations
Bird, .. Weinberg, .. Madau, et al

MW-like disk galaxy simulations, trace SF within disk.  At z=0, <2Gyr stars mainly occupy the stellar spheroid, with the oldest stars having more centrally concentrate profiles.  The younger populate disks of progressively longer radial scale length and shorter vertical scale height.  At a given radius, superposition of old, vertically-extended and young, vertically-cmopact stars gives rise to a double-exponential profiles like that observed in the MW (although the superposition is continuous and smooth).  Formation history: find that the trends of spatial structure and kinematics with stellar age are largely iprinted at birth, or immediately thereafter.  Stars that form during the active merger phase at z>3 are quickly scattered into rounded, kinematically hot configurations.  The oldest disk stars form in structures that are radially compact and relatively thick, while subsequent stars form in progressively larger, thinner, colder configurations from gas with increasing levels of rotational support.  The disk thus forms "inside-out" in a radial sense and "upside-down" in a vertical sense.  Secular heating and radial migration influence the final state of each star, but the changes they produce are small compared to the trends established at formation.  The predicted correlations of stellar age with spatial and kinematic structure are in good qualitative agreement with the correlations observed for mono-abundance stellar populations in the MW.

1301.0631
The EGNoG survey: gas excitation in normal galaxies at z~0.3
Bauermeister, Blitz, ... et al

Important to understand the conditions of gas in systems of high-z and low SFR to properly infer their molecular gas content.  The rotational transition of CO provide an excellent probe of gas excitation conditions in these galaxies.  Present results from the gas excitation sample of the Evolution of molecular Gas in Normal Galaxies survey at CARMA.  Report robust detections of both CO 1-0 and 3-2 lines in 3 galaxies (SFR 40-65 Msun/yr, 2e11 Msun) out of 4.  Conclude that the excitation of the gas in these massive, highly SF galaxies is consistent with normal SF galaxies such as local spirals, not SB systems like the local ULIRGs.  Since the survey selects from MS SF galaxies, this result is applicable to studies of MS galaxies at intermediate and high z; supports assumptions made in studies that find molecular gas fractions in SF galaxies at z~1-2 to be an order of magnitude larger than what is observed locally.

1301.0655
Metal-mass-to-light ratios of the Perseus cluster out to the virial radius
Matsushita et al

XMM-Newton data of Perseus to ~1Mpc (0.5 r_vir); use flux ratios of Lya of H-like Si and S to Ka line of He-like Fe, the abundance ratios of Si/Fe and S/Fe of the ICM derived using some plasma code.  Temperature dependence of the line ratio limits the systematic uncertainty in the derived abundance ratio.  The Si/Fe and S/Fe in ICM show no radial gradient.  The emission-weighted averages of Se/Fe and S/Fe ratios outside the cool core are 0.92 in solar units.  Indicates most Fe was synthesized by SNIa.  Collect K-band luminosities of galaxies and calculate the ratio of Fe and Si mass in the ICM to K-band luminosity, Fe-mass-to-light ratio (IMLR) and Si-Mass-to-light ratio (SMLR); within ~1Mpc, the cumulative IMLR and SMLR increase with radius.  Using the cumulative IMLR profile, discuss the past SNIa rate.

1301.0776
The Atacama cosmology telescope: likelihood for small-scale CMB data
Dunkley ... Das, ... et al

ACT measured CMB fluctuations to arcminute scales; at small scales the fluctuations in the primordial CMB become increasingly obscured by extragalactic FG and secondary CMB signals.  Present results from a 9 parameter model describing these secondary effects, including the thermal and kinematic SZ and kSZ power; the clustered and Poisson-like power from CIB sources, and their frequency scaling; the tSZ-CIB correlation coefficient; the extragalactic radio source power; and thermal dust emission from Galactic cirrus in two different regions of the sky.  In order to extract cosmological parameters, describe a likelihood function for the ACT data, fitting this model to the multi-frequency spectra in the multipole range 500<ell<10000.  Extend the likelihood to include spectra from SPT at 3 different frequencies.  Accounting for different radio source levels and Galactic cirrus emission, the same model provides and excellent fit to both datasets simultaneously, with chi2/dov=675/697 for ACT, and 96/107 for SPT.  Then use the multi-frequency likelihood to estimate the CMB power spectrum from ACT in bandpowers, marginalizing over the secondary parameters.  This provides a simplified 'CMB-only' likelihood in the rate 500<ell<3500 for use in cosmological parameter estimation.

1301.0780
The Atacama Cosmology Telescope: the stellar content of galaxy clusters selected using the Sunyaev-Zel'dovich effect
Hilton et al

Measurement of the stellar mass component of galaxy clusters selected via SZ.  Measure 3.6 and 4.5 um galaxy luminosity functions, characterize m* and faint-end slope (alpha) to be similar to those for IR-selected cluster samples.  Scaling of Y500/y0 with BCG stellar mass and total cluster stellar mass.  See no evidence for a shortfall of baryons relative to the cosmic mean value.

1301.0816
The Atacama cosmology telescope: Sunyaev-Zel'dovich selected galaxy clusters at 148 GHz from three seasons of data
Hasselfield et al

A catalog of 68 clusters, 19 are new.  

1301.0824
The Atacama cosmology telescope: cosmological parameters from three seasons of data
Sievers et al

Present constraints on cosmological and astrophysical parameters from hihg-res microwave background maps at 148 GHz and 218 GHz by ACT.  Power of ell^2 C_ell/2pi of tSZ power spectrum measured at 3.4 muK^2 at ell=3000, kSZ has upper limit (95% CL) at 8.6 muK^2.  Combine ACT with WMAP7, find excellent consistency with LCDM.  Constrain the number of effective relativistic degrees of freedom in the early universe to be Neff=2.78 pm 0.55, in agreement with canonical value of Neff=3.046 for 3 massless neutrinos.  Constrain sum of neutrino mass to be Sigma m_nu < 0.39 eV at 95% CL with ACT, WMAP7, BAO and H0 combined.  Constrain amount of primordial He to be Yp=0.226pm0.032, and measure no variation in the fine structure constant alpha since recombination.  Find no evidence for any running of the scalar spectral index: dns/dlnk = -0.003pm0.013.

Day 365

Saturday.  January 5th, 2013.

1301.0024
Relative velocity of dark matter and baryons in clusters of galaxies and measurements of their peculiar velocities
Dolag, Sunyaev

Peculiar velocities of individual clusters of galaxies might be measured using the kinematic SZ effect.  Next generation of X-ray telescopes promise first detections of motion of the ICM within clusters.  Use cosmo sims with many clusters and very high resolution on some clusters to investigate how the presence of baryons and their associated physical processes like cooling and SF are affecting the systematic difference between mass averaged velocities of DM and the ICM inside a cluster.  Quantify the peculiar motion of galaxy clusters as function of the large scale environment; demonstrate that in very massive systems, the relative velocity of the ICM compared to the cluster peculiar velocity add significant scatter onto the inferred peculiar velocity, especially when measurements are limited to the central regions of the cluster.  Depending on the aperture used, this scatter varies between 50% and 20%, when going from the core (<10% r_vir) to the full cluster (~r_vir).

1301.0060
On the validity of the perturbative approach for strong lensing: local distortion for pseudo-elliptical models
Dumet-Montoya, ... Gill, et al

The perturbative approach (PA) provides analytic solutions for gravitational arcs by solving the lens equation linearized around the Einstein ring solution, a method for lens inversion and simulations that can be used for generic lens models.  In this paper, aim to quantify the domain of validity of this method for caustics, critical curves, and the deformation cross section (the arc cross set ion in the infinitesimal circular source approximation).  Consider lens models with elliptical potentials (Singular Isothermal Elliptic Potential and Pseudo-Elliptical NFW models).  Show that the PA is exact for the first model.  For the second, obtain contraints on the model parameter space (given by the potential ellipticity parameter \epsilon and characteristic convergence \kappa_s) such that the PA is accurate for the aforementioned quantities.  In this process, obtain analytic expressions for several lensing functions, which are valid for the PA in general.  The determination of this domain of validity could have significant implications for the use of the PA, but it still needs to be probed with extended sources.

1301.0163
Lithium-rich field giants in the Sloan digital sky survey
Martell, Shetrone

A search for post-main sequence field stars in the Galaxy with atypically large Li abundances.  Using SDSS spectra along with high-res followup, identify 23 post-turnoff stars with log epsilon(Li) > 1.95, including 14 with >2.3 and 8 with >3.0, well above the low level expected for evolved stars.  Comparison with theoretical isochrones indicates that some of these Li-rich stars are affiliated with the upper red giant branch, the AGB and the red clump rather than the RGB bump, which is a challenge to existing models of Li production in evolved stars.

1301.0217
Characterization of potentially habitable planets: retrieval of atmospheric and planetary properties from emission spectra
von Paris, Hedelt, Selsis, Schreier, Trautmann

Sear for atmospheric signatures to establish planetary habitability and the presence of life: want to quantify the accuracy of retrieved atmospheric parameters which might be obtained from IR emission spectroscopy.  Use synthetic observations of hypothetical habitable planets constructed with a parameterized atmosphere model, a high-res radiative transfer model and a simplified noise model.  ... find that emission spectroscopy could provide weak limits on surface conditions of terrestrial planets, hence their potential habitability; although unlikely to allow characterization of the composition of the atmosphere of a habitable planet.  CO2 content to <2 orders of magnitude, O3 biosignature remains marginal.  Other methods such as transmission spectroscopy or orbital photometry are probably needed in order to give additional constraints and break degeneracies.

1301.0235
Hot moons and cool stars
Heller, Barnes

Kepler photometry can detect extrasolar moons.  First review observational and analytical techniques recently proposed for exomoon detection.  Then discuss the prospects of characterizing potentially habitable extrasolar satellites.  With moons being much more numerous than planets in the solar system and with most exoplanets found in the stellar habitable zone being gas giants, habitable moons could be as abundant as habitable planets. However, satellites orbiting planets in the habitable zones of cool stars will encounter strong tidal heating and likely appear as hot moons.

1301.0285
The equations of magnetoquasigeostrophy
Umurhan

"Magneto quasi geo strophy": Dynamics contain in magnetized layers of exoplanet atomospheres.  Framework development.

1301.0311
Venus transits: history and opportunities for planetary, solar and gravitational physics
Sigismondi, Wang, Rocher, Reis-Neto

Compare 2012 transit to 2004.  Thickness of the atmosphere of Venus, its aureole and the effect of oblateness and other asphericities in the figure of the Sun are taken into consideration, as well as the black drop effect.  A new extrapolation method for the contact times is presented.  The next Mercury transit in 2016 will be fully visible from Europe, and the data will be gathered in view of this new method of analysis, to obtain the solar diameter.

1301.0320
The radial distribution of star formation in galaxies at z~1 from the 3D-HST survey
Nelson, van Dokkum, et al

The assembly of galaxies can be described by the distribution of their star formation as a function of cosmic time.  Thanks to the WFC3 grism on HST, it is now possible to measure this beyond the local Universe.  Present the spatial distribution of Halpha emission for a sample of 54 strongly SF galaxies at z~1 in the 3D-HST Treasury survey.  By stacking the Halpha emission, find that SF occurred in approximately exponential distributions at z~1, with median Sersic index of n=1.0pm0.2.  The stacks are elongated with median axis ratios of b/a=0.58pm0.09 in Halpha, consistent with (possibly thick) disks at random orientation angles.  Keck spectra obtained for a subset of 8 of the galaxies show clear evidence for rotation, with inclination-corrected velocities of 90 to 330 km/s.  The most straightforward interpretation of our results is that SF in strongly SF galaxies at z~1 generally occurred in disks.  The disks appear to be "scaled-up" versions of nearby spiral galaxies:  they have EW(Ha)~100 Angstroms out to the solar orbit and they have SF surface densities above the threshold for driving galactic scale winds.

1301.0321
Strontium and Barium in early-type galaxies
Conroy, van Dokkum, Graves

Abundance pattern 'chronometers' include the alpha and Fe-peak elements, which are created on short and long timescales, respectively.  These two clocks have been widely used to estimate SF timescales from moderate-resolution spectra of early-type galaxies.  Elements formed via s-process neutron captures (eg., Sr and Ba) comprise a third type of chronometer, as the site of the main s-process is believed to be intermediate and low-mass asymptotic giant branch stars.  The [alpha/Ba] ratio in particular should provide a powerful new constraint on the SFH of galaxies, in part because it is insensitive to the uncertain distribution of SNIa detonation times and the overall Ia rate.  Present new measurements of the abundance of Sr and Ba in nearby early-type galaxies by applying SPS tools to high S/N optical spectra.  Find a strong anti-correlation between [Mg/Fe] and [Ba/Fe], and a strong positive correlation between [Mg/Ba] and galaxy velocity dispersion.  These trends are consistent with the idea that more massive galaxies formed their stars on shorter timescales compared to less massive galaxies, and rule out several outer proposed explanations for the observed super-solar [Mg/Fe] values in massive galaxies.  In contrast, [Sr/Fe]~0, with no strong variation across the sample.  It is difficult to interpret the Sr trends without detailed chemical evolution models owing to the multiplicity of proposed nucleosynthetic sites for Sr.

1301.0360
Gravitational lensing effects on sub-millimetre galaxy counts
Er, Li, Mao, Cao

Study of effect on the number counts of SMG due to gravitational lensing.  Explore the effects on the magnification cross section due to halo density profiles, ellipticity and cosmological parameter (sigma_8).  Show that the ellipticity does not strongly affect the magnification cross section in gravitational lensing while the halo radial profiles do.  Since the baryonic cooling effect is stronger in galaxies than in clusters, galactic haloes are more concentrated.  In light of this, a new scenario of two halo population model is explored where galaxies are modeled as a singular isothermal sphere profile and clusters as a NFW profile.   Find the transition mass between the two has modest effects on the lensing probability.  The cosmological parameter sigma_8 alters the abundance of haloes and therefore affects our results.  Compared with other methods, this model is simpler and more realistic.  The conclusions of previous works is confirm that gravitational lensing is a natural explanation for the number count excess at the bright end.

1301.0371
Cool gas in high redshift galaxies
Carilli, Walter

Molecular gas has now been observed in ~200 galaxies at z>1, including numerous AGN host-galaxies out to z~7, highly SF galaxies (median z ~ 2.5), and increasing samples of 'main-sequence' SF galaxies at z~1.5-2.5.  Studies have moved well beyond simple detections to dynamical imaging to kpc-scale resolution, and multi-line, multi-species studies that determine the physical conditions in the interstellar medium.  Observations of the cool gas are the required complement to studies of the stellar density and SFH of the Universe, as they reveal the phase of the interstellar medium that immediately precedes SF.  Current observations suggest that the order of magnitude increase in the cosmic SFR density from z~0 to 2 is commensurate with a similar increase in the gas to stellar mass ratio in SF disk galaxies.  Progress has been made on determining the CO luminosity to H2 mass conversion factor at high-z, and the dichotomy between high versus low depletion time values for main sequence versus starburst galaxies, respectively with a likely dependence on metallicity and other local physical conditions.  Studies of atomic fine structure line emission are rapidly progressing, with some tens of galaxies detected in the exceptionally bright CII 158 micron line to date.  This line is proving to be a unique tracer of galaxy dynamics in the early Universe and has the potential to be the most direct means of obtaining spectroscopic redshifts for the first galaxies during cosmic reionization.

1301.0462
Searching for neutral hydrogen haloes around z ~ 2.1 and z ~ 3.1 Ly-alpha emitting galaxies
Feldmeier, ... Gawiser, ... Acquiaviva, ... et al

Stack 187 LAEs at z=2.1, and 241 LAEs at z=3.10, and 179 LAEs at z=3.12, obtain mean surface brightness maps that reach 9.9, 8.7, 6.2e-19 ergs/cm^2/s/arcsec^2 in the emission line.  Find that limits are 5-10 times larger than what is expected from Poisson BG fluctuations; these uncertainties are often underestimated in the literature.  At z~3.1, find marginal evidence for extended haloes with scale lengths of 5-8 kpcs, and demonstrate that sub-samples of galaxies with low equivalent widths and brighter continuum magnitudes are more likely to posses such haloes.  At z~2.1, find no evidence of extended Lya emission down to detection limits.  Compare these findings to other measurements, discuss possible instruemental and astrophysical reasons for the discrepancies, including possible evolution of Lya halo properties from z~3.1 to 2.1.

1301.0475
Cross-correlation of WMAP7 and the WISE full data release
Kovacs et al

Cross correlate WMAP7 temperature map to WIde-field Infrared SUrvey Explorer galaxy map; find a positive cross-correlation signal [at what significance?].  Results are fully consistent with a LCDM universe, although not statistically significant.  Findings are robust against changing the galactic latitude cut from |b|>10 to |b|>20 and no color dependence was detected.  Confirm higher significance correlations found in the preliminary data release.  The change in significance is consistent with cosmic variance.

1301.0530
The origin and optical depth of ionizing radiation in the "Green Pea" galaxies
Jaskot, Oey

Observations of SF galaxies at low-z generally indicate low LyC (Lyman continuum) escape fractions, though at high-z they likely caused reionization of the universe.  However, the extreme [OIII]/[O II] ratios of the z=0.1-0.3 Green Pea galaxies may be due to high escape fractions of ionizing radiation.  To analyze the LyC optical depths and ionizing sources of these rare, compact starbursts, compare nebula photoionization and stellar population models with observed emission lines in the Peas' SDSS spectra.  Focus on the 6 most extreme Green Peas.  The Balmer line equivalent widths and He I emission in the extreme Peas support young ages of 3-5 Myr, and He II emission in 5 extreme Peas signals the presence of hard ionizing sources.  Ionization by AGN or high-mass X-ray binaries is inconsistent with the Peas' line ratios and ages.  Although stacked spectra reveal no WR features, tentatively detect WR features in the SDSS spectra of 3 extreme Peas.  Based on the Peas' ages and line ratios, find that WR stars, chemically homogeneous O stars, or shocks could produce the observed He II emission.  If hot stars are responsible, the Peas' optical depths are ambiguous.  However, accounting for emission from shocks lowers the inferred optical depth and suggests that the Peas may be optically thin.  The Peas' ages likely optimize the escape of Lyman-continuum radiation; they are old enough for supernovae and stellar winds to reshape the interstellar medium, but young enough to possess large numbers of UV-luminous O or WR stars.