Day 321

Tuesday, Wednesday skipped.  Thursday.

1210.7236
Massive and newly dead: discovery of a significant population of galaxies with high velocity dispersions and strong Balmer lines at z~1.5 from Deep Keck Spectra and HST/WFC3 imaging
Bezanson, van Dokkum, van de Sande, Franx, Kriek

8 galaxies at z~1.5 with high M* (photometrically determined), with 5 previously observed others, for spectra and HST/WFC imaging.  These 13 have high velocity dispersions, with a median of sigma=301 km/s.  This high value is consistent with their relatively high stellar masses and compact sizes.  Study their stellar populations using the strength of Balmer absorption lines (not sensitive to dust absorption); find large range, many showing strong lines indicating young ages.  Median Hdelta_A equivalent width, determined directly or inferred from the H10 line, is 5.4 Angstroms, indicating a luminosity-weighted age of ~1 Gyr.   Such high dispersion galaxies with young ages are extremely rare in the local universe.  No simple correlation with rest-fram U-V color: some of the reddest galaxies have very strong Balmer absorption lines.  Results demonstrate that many high-dispersion galaxies at z~1.5 were quenched recently.  Implies there must be a population of SF progenitors at z~2 with high velocity dispersions or line widths, which are notoriously absent from CO/Halpha selected surveys.

1210.7240
Supernova light curves powered by fallback accretion
Dexter, Kasen

As the title says: late time (>days) power associated with the accretion of this "fallback" material may significantly affect the optical light curve, in some cases producing super-luminous or otherwise peculiar supernovae.  Accretion rate onto proto-NS or BH decreases as Mdot~t^-5/3 at late times, but its normalization can be significantly enhanced at low explosion energies, in very massive stars, or in a strong reverse shock wave forms at the helium/hydrogen interface in the progenitor.  If resulting super-Eddington accretion drives an outflow which thermalizes in the outgoing ejecta, the supernova debris will be re-energized at a time when photons can diffuse out efficiently; the resulting light curves are different and more diverse than previous fallback SNe models which ignored the input of accretion power and produced short-lived, dim transients.  The possible outcomes when fallback accretion power is significant include super-luminous (>1e44 ergs/s) Type Ii events of both short and long durations, as well as luminous Type I events from compact stars that may have experienced significant mass loss.  Accretion power may unbind the remaining infalling material, causing a sudden decrease in the brightness of some long duration Type II events.  This scenario may be relevant for explaining some of the recently discovered classes of peculiar and rare supernovae.

1210.7263
The black hole mass - stellar velocity dispersion relationship for quasars in the Sloan digital sky survey data release 7
Salviander, Shields

M-sigma relation in SDSS7 for 0.1<z<1.2.  M_BH estimated using "photoionization method" with the broad Hbeta or MgIi emission line and the queasar continuum luminosity.  For the stellar velocity dispersion, use the narrow [OIII] or [OII] emission line as a surrogate.  Break lower-redshift subsample into black hole mass bins and probe the M-sigma relationship for constant black hole mass.  The M-sigma relationship for the (M>1e9 Msun) and (M<1e7.5 Msun) BH appears to evolve significantly, but most or all of this apparent evolution can be accounted for by various observational biases due to intrinsic scatter in the relationship and to uncertainties in observed quantities.  The M-sigma relationship in the middle mass range show minimal change with redshift.  The overall results suggest a limit of pm 0.2 dex on any evolution in the M-sigma relationship for quasars out to z~1 compared with the relationship observed in the local universe.  Intrinsic scatter may also provide a plausible way to reconcile the wide range of results of several different studies of the black hole-galaxy relations.

1210.7276
Constraints on non-gaussianity from Sunyaev--Zeldovich cluster surveys
Mak, Pierpaoli

Fisher matrix analysis of SZ surveys in constraining deviations from Gaussian distribution of primordial density perturbations.  Use cluster number counts and clustering properties to forecast limits on fnl; effects on mass function and halo bias considered.  Self-calibration for mass-observable scaling relation, evaluate constraints for SPT, Planck, CCAT-like, SPTPol and ACTPol surveys.  Scale dependence of halo bias induced by local NG provides strong constraints on fnl, while the results from number count are two orders of magnitude worse.  ...  most info from power spectrum, so only mild dependence on mass-observable relation.

1210.7303
Effect of baryonic feedback on two- and three-point shear statistics: prospects for detection and improved modeling
Semboloni, Hoekstra, Schaye

Different baryonic feedback scenarios lead to significantly different two-point shear statistics (effect of feedback from galaxy formation on the matter distribution).  Extend work to 3-pt shear statistics.  Show: relative to the predictions of DM only models, the amplitude of the signal can be reduced by as much as 30-40% on scales of a few arcminutes.  As is the case for 2-pt shear tomography, 3-pt shear statistics with DM only models is plagued by a strong bias.  Find: baryonic feedback models affect 2- and 3-pt statistics differently, can be used to asses the fidelity of various feedback models, e.g., in Euclid.  Argue in favor of phenomenological feedback models that can capture the relevant effects of feedback processes in addition to changes in cosmology.  Construct such a model by modifying the standard DM only halo model to characterize the generic effects of energetic feedback using a small number of parameters.  Demonstrate that WL surveys can mitigate the effects of baryonic processes, such as outflows driven by feedback from SF and AGN, by marginalising over the feedback parameters.

1210.7319
Signatures of X-rays in the early universe
Mesinger, Ferrara, Spiegel

X-rays: long mean free paths, efficient heating of IGM---can have impact on thermal and ionization history of the Universe.  (i) reionization history: extended ionized epoch ~10%.  (ii) reionization history: more uniform morphology, with modest impact compared to the global neutral fraction.  Robust signature, since change in morphology cannot be countered by increasing bias of the ionizing sources.  (iii) kSZ effect: at fixed reionization history, decreases the kSZ power at l=3000 by 0.5 uK^2.  This X-ray dominated reionization is the only (marginally) consistent model with SPT results, assuming no tSZ-dusty galaxy correlation.  Conclude: there should be a sizable tSZ-dusty galaxy signal.  (iv)  Comsic 21cm signal: impact of x-rays modest during the advanced stages of reionization (xH<0.8).  Largest impact of X-rays is to govern IGM heating---heating results in 21 cm power spectrum which is 10-100x higher than native estimates which ignore the reionization-to-x-ray-heating overlap.  More 21cm emission in this case!

1210.7343
Determining distances using astroseismic methods
Aguirre et al

Use Astroseismology to get: masses, radii, effective temperatures, bolometric fluxes, and thus distances for field stars.  Agreement to 5%, compared to Hipparcos parallaxes.

1210.7563
Gas sloshing and radio galaxy dynamics in the core of the 3C449 Group
Lal, et al

Unusual entropy distribution from 30 ks Chandra observation, and what looks like a strong shock arround the inner radio lobes.  No evidence of temperature increase inside the edge from 140 ks Chandra observation, suggesting that the edge is a "sloshing" cold front due to a merger within the ~1.3-1.6 Gyrs.  ...

1210.7681
The rates and time-delay distribution of multiply imaged supernovae behind lensing clusters
Li, Hjorth, Richard

The rate of core-collapse SNe suitable for time delay obaservations is 0.044 pm 0.015 per year, for magnitude threshold of m_AB~27.0.

1210.7690
Origins of weak lensing systematics, and requirements on future instrumentation (or knowledge of instrumentation)
Massey, Hoekstra, Kitching, Rhodes, ... Mellier, Meneghetti, Miller, ... Schrabback

PSF instability, CCD non-idealities in shape measurements; explain additive and multiplicative systematics in current measurements.  Overall performance driven by telescope's absolute performance, and our knowledge of its performance.  Residual shear measurement biases through to cosmological param constraints.  Additive bias <1.8e-12 and mult bias < 4e-3 required for Stage IV WL surveys, which can be budgeted in HW, calibration data and SW.  If instrumentation is stable, find extant shear measurement SW from GREAT10 already meet requirements on galaxies for a 2d cosmic shear analysis from space.  Used on fainter galaxies or for 3d cosmic shear tomography, existing algorithms would need calibration on simulations to avoid introducing bias at a level similar to the statistical error.  Requirements on hardware and calibration data are discussed in more detail in the next paper.

1210.7691
Defining a weak lensing experiment in space
Cropper, Hoekstra, Kitching, ... Massey, Miller, Mellier, Rhodes, Rowe, Pires, ... et al

Main contribution factors: reconstruction of the PSF, and the correction of the CTI.

1210.7771
AMI SZ observations and Bayesian analysis of a sample of six redshift-one clusters of galaxies
AMI consortium

16GHz SZ observations using AMI (Arcminute microkelvin imager) and subsequent Bayesian analysis of six galaxy clusters at redshift z~1.  2 cluster models: isothermal beta model and DM GNFW model to derive a formal detection probability and the cluster parameters.  Find M_200 for each model, which agree with each other (in 2 clusters).  

1210.7809
Exploring the NRO opportunity for a Hubble-sized wide-field near-IR space telescope -- NEW WFIRST
Dressler, Spergel, ... Hirata, ... Perlmutter, ... Riess, ... Stern, Weinberg, et al

Scientific technical and programmatic issues related to the use of NRO 2.4m telescope for the WFIRST initiative of the 2010 Decadal survey.  Dubbed "New WFIRST", will achieve goals of NWNH Decadal survey for the WFIRST core programs of DE and Microlensing Planet Finding, with the crucial benefit of deeper and/or wider NIR surveys for GO science and a potentially Hubble-like guest observer program.  NEW WFIRST could also include a coronagraphic imager for direct detection of dust disks and planets around neighboring stars, a high-priority science and technology precursor for future ambitious programs to image Earth-like planets around neighboring stars.

1210.7880
Inflation and birth of cosmological perturbations
Sasaki

Inflation review: with cosmological perturbations from inflation.  Standard single-field slow-roll inflation, curvature and tensor perturbations produced from it, possible sources of NL, non-Gaussian perturbations in other models of inflation.  Describe so-called delta-N formalism, a tool for evaluating NL curvature perturbations on super Hubble scales.

1210.5282
The WARPS survey.  VIII. Evolution of the galaxy cluster X-ray luminosity function
Koens, ... Ebeling, ... et al

Measurements of cluster X-ray luminosity function (XLF) from wide angle Rosat pointed survey (WARPS) and quantify its evolution.  Final sample of 124 clusters, complete above 6.5e-15 erg/s/cm2, with members out to z~1.05 and a sky coverage of 70.9 deg2.  We find significant evidence for negative evolution of the XLF [??] which complements the majority of X-ray cluster surveys.  Quantify this evolution, perform a likelihood analysis, and conclude that the evolution is driven by a decreasing number density of high luminosity clusters with z, while the bulk of the cluster population remains nearly unchanged out the z~1.1, as expected in a low density universe.  Results found to be insensitive to a variety of sources of systematic uncertainty that affect XLF determination.  Fully account for uncertainties in the locals XF on the measured evolution; find that the detected evolution remains significant at the 95% level.  Observe a significant excess of clusters in the WARPS at 0.1<z<0.3 and LX~2e42 erg/s compared with the reference low-z XLF, or the Bayesian fit to the WARPS data.  Find that the excess cannot be explained by sample variance or Eddington bias, and is unlikely to be due to problems with the survey selection function.