Day 682

Thursday, Friday.

1406.4668
Intrinsic alignment of simulated galaxies in the cosmic web: implications for weak lensing surveys
Codis et al

The IA of galaxy shapes and their cross-correlation with the surrounding DM tidal field are investigated using the 1600k, z=1.2 synthetic galaxies extracted from the high-res cosmo hydro sim Horizon-AGN.  One- and two-point statistics of the spin of the stellar component are measured as a function of mass and color.  For the low-mass galaxies, this spin is locally aligned with the tidal field 'filamentary' direction while, for the high-mass galaxies, it is perpendicular to both filaments and walls.  The bluest galaxies of the synthetic catalog are more strongly correlated with the surrounding tidal field than the reddest galaxies, and this correlation extends up to 10 Mpc/h comoving distance.  Also report a correlation of the projected ellipticities of blue, intermediate mass galaxies on a similar scale at a level of 1e-4 which could be a concern for cosmic shear measurements.  Do not report any measurable intrinsic alignments of the reddest galaxies in the sample.  This work is a first step toward the use of very realistic catalog of synthetic galaxies to evaluate the contamination of WL measurement by IA.

1406.4728
Damping of glacial-interglacial cycles from anthropogenic forcing
Haqq-Misra

Climate variability over the past million years shows a strong glacial-interglacial cycle of ~100k years as a combined result of Milankovitch orbital forcing and climatic resonance.  It has been suggested that anthropogenic contributions to radiative forcing may extend the length of the present interglacial, but the effects of anthropogenic forcing on the periodicity of glacial-interglacial cycles has received little attention.  Demonstrate the moderate anthropogenic forcing can act to damp this 100k year cycle and reduce climate variability from orbital forcing.  Future changes in solar insolation alone will continue to drive a 100k year climate cycle over the next million years, but the presence of anthropogenic warming can force the climate into an ice-free state that only weakly responds to orbital forcing.  Sufficiently strong anthropogenic forcing that eliminate the glacial-interglacial cycle may serve as an indication of an epoch transition from the Pleistocene to the Anthropocene.

1406.4542
Computing and using metrics in the ADS
Henneken et al

"Discuss how the ADS can be used to quench the first for impact measures."

1406.4859
Herschel-Atlas and ALMA: HATLAS J142935.3-002836, a lensed major merger at redshift 1.027
Messias et al

A system comprising of a foreground edge-on disk galaxy (at z=0.218) with an almost complete Einstein ring around it.  The background source (z=1.027) is magnified by a factor of ~8-10 depending on wavelength.  It is comprised of two components and a tens of kpc long tidal tail resembling the Antennae merger.  Utilized multi wavelength data.

1406.4871
Can weak lensing surveys confirm BICEP2?
Chisari, Dvorkin, Schmidt

The detection of B_modes in the CMB polarization by BICEP2, if interpreted as evidence for a primordial gravitational wave background, has enormous ramifications for cosmology and physics.  It is crucial to test this hypothesis with independent measurements.  A gravitational wave background leads to B-modes in galaxy shape correlations (shear) both through lensing and tidal alignment effects.  Since the systematics and foregrounds of galaxy shapes and CMB polarization are entirely different, a detection of a cross-correlation between the two observables would provide conclusive proof for the existence of a primordial gravitational wave background.  Find that upcoming weak lensing surveys will be able to detect the cross-correlation between B-modes of the CMB and galaxy shapes.  However, this detection is not sufficient to confirm or falsify the hypothesis of a primordial origin for CMB B-mode polarization.