Day 147

Tuesday.  IKEA shipping day.  I hope I haven't missed anything.


1111.6108
Radiative signature of magnetic fields in internal shocks
Mimica, Aloy


Model internal shocks as being caused by collisions of homogeneous plasma shells with non-zero relative velocity.  Obtain that radiative efficiency is largest where one shell is weakly and the other strongly magnetized.  Propose a way to distinguish observationally between weakly magnetized from magnetized internal shocks by comparing the maximum frequency of the inverse-Compton and synchrotron part of the spectrum to the ratio of the inverse-Compton and synchrotron fluence.  [??]  Results suggest that LBL blazars may correspond to barely magnetized flows, while HBL blazars could correspond to moderately magnetized ones.  Comparing to actual blazar observations, conclude that the magnetization of typical blazars is sigma<~0.01.


1111.6111
A new dynamical parameter for the study of sticky orbits in a 3d galactic model
Zotos


Study the regular or chaotic character of the motion in the central parts of an elliptical galaxy, which hosts a massive and dense nucleus.  


1111.6132
The Taiwan Extragalactic Astronomical Data Center (TWEA-DC)
Foucaud, Hashimoto


Propose 1Pb of data storage dedicated to extragalactic astronomy by 2015--first step toward building of a National Virtual Observatory.  Photometry from public surveys, database or on-the-fly, access to raw and reducible data from archives, specific analysis tools through user-friendly interface.  First phase: focus on multiband catalog cross-matching; fully functional in 2011.


1111.6585
The Milky Way has no thick disk
Bovy, Rix, Hogg


MW's stellar disk are known to have different vertical scale heights depending on the stellar sub-population, their thickness increasing with age.  Using SEGUE spectro data, show that mono-abundance subpopulation (defined in [alpha/Fe]-[Fe/H] space, are well described by single exponential spatial-density profiles in both the radial and the vertical direction; therefore any star of a given abundance is clearly associated with a sub population of scale height h_z.  Work out how to determine the stellar surfac-mass density contributions at the solar radius R_0 of each sub population, accounting for the survey selection function, and for the fraction of the stellar population mass that is reflected in the spectroscopic target stars given populations of idfferent abundances and their presumed age distributions.  Taken together, this enables derivation of Sigma_R0(H_z), the surface-mass contributions of stellar populations with scale height h_z.  Surprisingly, find no hint of thin-thick disk bi-modality in the mass-weighted scale-height distribution, but a smoothly decreasing function, approximately Sigma_R0(h_z) \propto exp(-h_z), from h_z~200pc to 1kpc.  As h_z is ultimately the structurally defining property of a thin or thick disk, this shows clearly that the MW has a continuous and monotonic distribution of disk thicknesses: there is no 'thick disk' sensibly characterized as a distinct component.  Discuss how result is consistent with evidence for seeming bi-modality in purely geometric disk decompositions, or chemical abundances analysis.


1111.6189
X-ray, lensing and SZ triaxial analysis of Abell 1835 out to R_200
Morandi, Limousin, Sayers, Golwala, Czakon, Pierpaoli, Ameglio


Triaxial joint analysis of A1835 with X-ray, SL and SZ data.  Construct 3d structure of both DM and IC gas, and the level of non-thermal pressure of the IC gas.  Find that the intermediate-major and minor-major axis ratios of DM ar 0.7 and 0.6 respectively, and the major axis of the DM halo is inclined wrt the los by 18 deg.  Present first observational measurement of the non-thermal pressure out to R_200, which has been evaluated to be a few percent of the total energy budget in the internal regions, while it reaches about 20% in the outer volumes.  Discuss implications of method for the viability of the CDM scenario, focusing on the concentration parameter C and the inner slope of the DM gamma in order to test the CDM paradigm for structure formation: measure gamma=1 and C=4.3, agrees with CDM.  Combination of X-ray/SL at high spatial resolution, capable to resolve cluster core; along with the SZ, more sensitive to the cluster outer volume, allows characterization of the level and the gradient of the gas entropy distribution and non-thermal pressure out to R_200, breaking the degeneracy among the physical models describing the thermal history of the ICM.


1111.6249
Toward tight gamma-ray burst luminosity relations
Qi, Lu


Seek luminosity relations of GRBs from 116 samples; find 3d correlation of E_peak/tau_RT/L tighter than the corresponding 2d correlations (E_peak/L and tau_RT/L).