Day 731

Wednesday.

1408.5407
The stellar-to-halo mass relations of local galaxies segregated by color
Rodriguez-Puebla et al

Derive the stellar-to-halo mass relations, SHMR, of local blue and red central galaxies separately, as well as the fraction of haloes hosting blue/red central galaxies.  Find that: 1) the SHMR of central galaxies is segregated by color, with blue centrals having a SHMR above the one of red centrals; at logMh~12, the Ms/Mh ratio of the blue centrals is ~0.05, which is ~1.7 times larger than the value of red centrals.  2) the intrinsic scatters of the SHMRs of red and blue centrals are ~0.14 and ~0.11 dex, respectively.  The intrinsic scatter of the average SHMR of all central galaxies changes from ~0.20 dex to ~0.14 dex in the 11.3<logMh<15 range.  3) the fraction of haloes hosting blue centrals at Mh=1e11 Msun is 87%, but at 2e12 Msun decays to ~20%, approaching to a few per cents at higher masses.  The characteristic mass at which this fraction is the same for blue and red galaxies is Mh~7e11 Msun.  Results suggest that at the SHMR of central galaxies at large masses is shaped by halo mass quenching (likely through shock virial heating and AGN feedback), but group richness also plays an important role: central galaxies living in less dense environments quenched their star formation later or did not quench it yet.  At low masses, processes that delay SF without invoking too strong SN-driven outflows could explain the high Ms/Mh ratios of blue centrals as compared to those of the scarce red centrals.

1408.5898
Strong lensing, time delays, and the value of H$_0$
Barnacka, Geller, Dell'antonio, Benbow

Why does the H0 value vary from 50-100 km/s/Mpc?  It may arise from different components of the quasar (e.g. the jet).  Misidentifying a variable emitting region in a jet with emission from the core region may introduce an error in the Hubble constant derived from a time delay.  Investigate the complex structure of sources as the underlying physical explanation of the wide spared in values of H0 based on gravitational lensing.  MC sims demonstrate the potentially large impact of the position of the variable emitting region on H0 determination.  The derived value of the Hubble constant is very sensitive to the offset between the center of the emission and the center of the variable emitting region.  Based on these simulations, propose using the value of H0 known from other techniques to spatially resolve the origin of the variable emission once the time delay is measured.  Advocate this method particularly for gamma-ray astronomy, where the angular resolution of detectors reaches approximately 0.1 degree; lensed blazers offer the only route for identify the origin of gamma-ray flares.  Large future samples of gravitationally lensed sources identified with Euclid, SKA, and LSST will enable a statistical determination of H0.  The method should also provide new insights into the structure of the sources and their cosmic evolution at different energies.

1408.5970
The Sloan Digital Sky Survey reverberation mapping project: technical overview
Shen et al

4 day cadence with SDSS with >30 epochs, plus 2 day cadence with CFHT or Steward, of 849 broad-line quasars.  SDSS-RM is the first major program to systematically explore the potential of RM for road-line quasars at z>0.3, and will investigate the prospects of RM with all major broad lines covered in optical spectroscopy.  It will provide guidance on future multi-object RM campaigns on larger scales, and is aiming to deliver more than tens of BLR lag detections for a homogeneous sample of quasars.