Day 541

Tuesday.  Thursday.  Friday.

1310.6754
Spectroscopic confirmation of the rich z=1.8 galaxy cluster JKCS 041 using the WFC3 grim: environmental trends in the ages and structure of quiescent galaxies
Newman, .. .Treu, … et al

98 redshifts whose precision is better by 20x than photo-z.  19 member galaxies found, 15 are quiescent, there are spatially aligned with diffuse X-ray emission.  Study the effect of environment on galaxy properties at early epochs.  More massive members (M*>1e11Msun) have a mean stellar age of 1.4pm0.3 Gyr, whereas lower-mass examples (10.5-11) have a young mean age of 0.9pm0.2 Gyr.  These ages agree closely with those inferred by Whitaker+, supporting the idea that the cluster environment is more efficient at truncating SF while not having a strong effect on the mean epoch of quenching.  In contrast to field samples, there is no sign of low-level Hbeta or OIII emission in the composite spectra [of the quiescents, or the cluster members that are not quiescent?].  By comparing the ellipticity distribution of the quiescent members to coeval field galaxies from CANDELS, find some evidence for a lower fraction of disk-like quiescent systems in JKCS041.  Do not detect a significant difference between the mass-radius relations of the quiescent JKCS041 members and the z~1.8 field sample.  Review claims of environmentally-dependent size growth of z>1 quiescent galaxies, and demonstrate how differences in morphological mixtures may complicate comparisons of sizes in different environments.  

1310.6774
Reverberation mapping with photometry
Zu, Kochanek, Kozlowski, Peterson

Explore feasibility of 1 and 2-band photometric reverberation mapping (RM) and compare to the results for spectroscopic RM.  Based on damped random walk modeling of quasar variability.  Find: 2-band photometric RM can be competitive with spectra RM for strong lines like Ha and Hb, and that the 1-band method is feasible, but requires very small photometric uncertainties.  For Palomar-Green quasars with both dual band and specter data, find consistent lags using the 2-band and spectra methods.  For OGLE-III and IV single band light curves of quasars behind the MCs, fail to robustly detect Ha lags despite the outstanding cadence and time span of the data due to the photometric uncertainties (0.02-0.04 mag).  Single-band RM for all lines and dual-band RM for lower EW lines are likely only feasible for statistical estimates of mean lags for large samples of AGN of similar properties (e.g., luminosity) rather than for individual quasars.  This approach is directly applicable to the time-domain programs within ongoing and future wide-field imaging surveys, and could provide robust lag measurements for an unprecedented number of systems.

1310.6784
CFHTLenS: Co-evolution of galaxies and their dark matter haloes
Hudson, Gillis, Coupon, Hildebrandt, Erben, Heymans, Hoekstra, Kitching, Mellier, Miller, Van Waerbeke, Bonnet, Fu, Kuijken, Rowe, Schrabback, Sembooni, van Uitert, Velander

Wide range of stellar mass (8.75<log M*/Msun<11.3) and 0.2<z<0.8 with CFHTLenS: M* to halo mass ratio (SHMR) reaches a maximum of 3.4% as a function of halo mass at ~1e12.5Msun (at z=0.5).  Evidence for significant evolution of the SHMR: the peak ratio falls as a function of cosmic time from 3.8% at z~0.7 to 3.0% at z~0.3, and shifts to lower stellar mass haloes.  These evolutionary trends are dominated by red galaxies, and are consistent with a model in which the stellar mass above which SF is quenched "downsizes" with cosmic time.  In contrast, the SHMR of blue, SF galaxies is well fit by a power law that does not evolve with time.  This suggests that blue galaxies form stars at a rate that is balanced with their DM accretion in such a way that they evolve along the SHMR.  This can be used to constrain the mean SFR of the galaxy population over cosmic time.  

1310.6789
X-ray measurement of the spin-down of Calvera: a radio- and gamma-ray-quiet pulsar
Halpern, et al

2009 to 2013, 59 ms X-ray pulsar spin down measured at P-dot=3.19e-15, corresponding to E-dot=6.1e35 erg/s, characteristic age tau_c=P/2P-dot = 2.9e5 yr, and surface dipole B-field strength B_s=4.4e11G.  Rules out mildly recycled pulsar, but could be an orphaned central compact object (anti-magnetar) with a B-field initially buried by SN debris and is now reemerging and approaching normal strength.  Also performed unsuccessful searches for high-E gamma-rays from Calvera in both imaging and timing of >100 MeV Fermi photons.  Upper limit of distance d < 2 kpc inferred from X-ray spectra implies gamma-ray luminosity limit of <3.3e32 erg/s; less than any pulsar of comparable E-dot.  Similar to a young radio pulsar, born outside of Galactic disk (lack of proper motion).  As an energetic, high-galactic-latitude pulsar, Calvera is unique in being undetected in both radio and gamma-rays to faint limits, which should place interesting constraints on models for particle acceleration and beam patterns in pulsar magnetospheres.  

1310.6802
Nova Aquilae 1918 (V603 Aql) faded by 0.44 mag/century from 1938-3013
Johnson et al

Old light curve from 1898-1918 and 1934-3013 using 22k archival magnitudes, which are in (or accurately transformed into) Johnson B and V mags.  Goal: se the evolution of the mass accretion rate on the century time scale, and test the long-standing prediction of the Hibernation model that old novae should be fading significantly in the century after their eruption is long over.  The 1918 nova eruption was completely finished by 1938 when the nova decline stopped, and when the star had faded to fainter than its pre-nova brightness of B=11.43pm0.03 mag.  Find the the nova light from 1938-3013 was significantly fading, with this being seen consistently in 3 independent data sets.  Find that V603 Aql is declining in brightness at an average rate of 0.44 pm 0.4 mag per century since 1938.  This work provides confirmation of an important prediction of the Hibernation model.  However, result does not uniquely point to the Hibernation model because other models of novae evolution are now making similar predictions.

1310.6810
Using the topology of large-scale structure in the WiggleZ dark energy survey as a cosmological standard ruler
Blake, James, Poole

Present new and accurate measurements of the cosmic distance-redshift relation, spanning 0.2<z<1, using the topology of LSS as a cosmological standard ruler.  Derived from analysis of the Minkowski functionals of density field traced by WiggleZ DES.  The Minkowski functionals are a set of statistics which completely describe the topological nature of each isodensity surface within the field, as a function of the density value.  Given the shape of the underlying matter PS, measured by fluctuations in the CMB radiation, the expected amplitudes of the Minkowski functionals are specified as an excursion set of a Gaussian random field, with minimal non-Gaussian corrections for the smoothing scales > 10 Mpc/h considered in this analysis.  The measured amplitudes then determine the cosmic distance D_V(z), which are obtained with 3-7% accuracies in 6 independent z slices, with the standard ruler originating in the known curvature of the model PS at the smoothing scale.  Introduce a new method for correcting the topological statistics for the sparse-sampling of the density field by the galaxy tracers, and validate overall methodology using mock catalogues from N-body simulations.  Distance measurements are consistent with standard models which describe the cosmic expansion history, and with previous analyses of BAOs detected by the WiggleZ survey, with the topological results yielding a higher distance precision by a factor of 2.  However, the full z-space PS shape is required to recover the topological distances, in contrast to the preferred length scale imprinted by BAOs, which is determined by simpler physics.

1310.6859
AGB nucleosynthesis at low metallicity: what can we learn from carbon- and s-elements-enhanced metal-poor stars
Abate, Pols, Izzard, Karakas

CEMP-s stars are very metal-poor stars with enhanced abundances of carbon and s-process elements.  They form a significant proportion of the very metal-poor stars in the Galactic halo and are mostly observed in binary systems.  This suggests that the observed chemical anomalies are due to mass accretion in the past from an AGB star.  Because CEMP-s stars have hardly evolved since their formation, the study of their observed abundances provides a way to probe models of AGB nucleosynthesis at low metallicity.  Include in the binary evolution model the results of the latest models of AGB nucleosynthesis and simulate a grid of 100k binary stars at Z=0.0001 in a wide range of initial masses and separations.  Compared modeled stars with a sample of 60 CEMP-s stars from the SAGA database of metal-poor stars.  For each observed CEMP-s star of the sample, found the modeled star that reproduces best the observed abundances.  The result of this comparison: able to reproduce simultaneously the observed abundance of the elements affected by AGB nucleosynthesis (e.g. C, Mg, s-elements) for about 60% of the stars in the sample.