Day 168

Sunday, New Years Day.  I wonder what happens if I add Lumosity on top of Astroph and Yoga stretching to my daily morning routine.  (I should get a life instead, probably.)


1112.5691
Effect of radiative transfer on damped Lyman-alpha and Lyman limit systems in cosmological SPH simulations
Yajima, Choi, Nagamine


Effect of local stellar radiation and UVB on the physical properties of DLAs and LLSs at z=3 using cosmological SPH simulations, with ART code post-processing.  Stellar population does not affect DLA and LSS cross section, but UVB significantly reduces it: because clumpy high-density clouds near young star clusters effectively absorb most of the ionizing photons from young stars.  A UVB model with a simple density threshold for self-shielding effect can reproduce the observed column density distribution very well.    [what is self-shielding?]  DLA on 10-30 kpc scale, LLS surrounding on 30-60 kpc scale.  DLA host halos have M=2.4e10 Msun, SFR=0.3 Msun/yr, M*=2.4e8 Msun, and Z/Zsun=0.1.  [is this almost like a regular galaxy?]  Some have SFR=1-20 Msun/yr, a typical SFR range for LBGs.  Median values of LSS host haloes are somewhat lower at 9e9 Msun, SFR=0.06 Msun/yr, M*=6.5e7 Msun and Z/Zsun=0.08.  


1112.5723
The SDSS DR7 Galaxy angular power spectrum
Hayes, Brunner, Ross


18M galaxies, 5.7k sq. deg. (removed reddened area, poor seeing >1.5", bright objects). Test for sysematics: calculate angular power spectra by SDSS stripe, find minimal effect from seeing and reddening.  Use 3 magnitude bins with mean redshifts of z=0.171, z=0.217, and =0.261 to examine the evolution of angular power spectrum.  Determine the theoretical linear angular power spectrum; Omega_m=0.31 pm 0.15 with linear bias of b=0.94 pm 0.04.


1112.5813
AGN populations studies for CTA
Inoue, for the CTA consortium


Cherenkov Telescope Array (CTA), the next generation gamma-ray telescope array, following the current Imaging Atmospheric Cherenkov Telescopes (IACT).  Many VHE source (>30 GeV) detections expected.  Expect to detect 50 to 160 blazars in 1 to 10 years from a blank field sky survey, 20 blazars above z=1.  Fermi blazars at z=2.49.


1112.5940
Prospects for detecting gamma-ray bursts at very high energies with the Cherenkov Telescope Array
Kakuwa, Murase, Toma, Inoue, Yamazaki, Ioka


CTA can detect GRBs too, with lower energy threshold, fast slewing capabilities, and larger effective area compared to satellite instruments: 0.1-0.2 GRB/yr during the prompt phase, and ~1 GRB/yr in the afterglow phase.


1112.5949
New insights on the duration distribution of long GRBs from Collapsars
Bromberg, Nakar, Piran, Sari


Collapsar model of LGRBs has a signature: appearance of a plateau in the duration distribution of the prompt GRB emission at times much shorter than the typical breakout time of the jet.  This plateau is evident in all major GRB satellate data.  This model also places limits on the size and masses of LGRB progenitors, suggests the existence of a large population of choked GRBs, and indicates that the 2s duration commonly used to separate Collapsars and non-Collapsars holds for BATSE and possibly FERMI GBM GRBs, but is inconsistent with the duration distribution of Swift GRBs.


1112.5955
X-ray view of the shock fron in the merging cluster abell 3376 with Suzaku
Akamatsu, Takizawa, Nakazawa, fukazawa, Ishisaki, Ohashi


Shock feature show temperature profile of almost flat radial shape with kT~4keV within 1/2 r200 and a rise by about 1keV inside the radio relic; across the relic region (0.6-0.8 r200), the temperature shows a remarkable drop from 4.7 keV to 1.3 keV-- a clear evidence that the radio relic corresponds to a shock front (possibly by a past major merger).  Mach number M~3 implied. 


1112.5975
Enhanced abundances in spiral galaxies of the Pegasus I cluster
Robertson, Shields, Blanc


Both Virgo and Pegasus clusters show correlation of H I deficiency to high interstellar metallicity.


1112.6005
First low-latency LIGO+Virgo search for binary inspirals and their EM counterparts
LIGO + Virgo Collaboration


False alarm rate of once every 6.4 days, falls far short of the requirement for a detection based solely on gravitational-wave data.