Day 1021

Thursday.


1512.02231
The large-scale 3-point correlation function of the SDSS BOSS DR12 CMASS galaxies
Slepian, Eisenstein, et al

Report a measurement of the large-scale 3PCF of galaxies using the largest dataset for this purpose to date; 777k LRGs in SDSS BOSS DR12 CMASS sample.  This work exploits the novel algorithm of Slepian&Eisenstein (2015) to compute the multiple moments of the 3PCF in O(N^2) time, with N the number of galaxies.  Leading-order perturbation theory models the data well in a compressed basis where one triangle side is integrated out.  Also present an accurate and computationally efficient means of estimating the covariance matrix.  With these techniques and redshift-space linear and non-linear biases are measured, with 2.6% precision on the former if sigma8 is fixed.  The data also indicates a 2.8 sigma preference for the BAO, confirming the presence of BAO in the 3PCF.


1512.02636
The link between the assembly of the inner dark matter halo and the angular momentum evolution of galaxies in the EAGLE simulation
Zavala, Frenk, Bower, Schaye, et al

Explore the co-evolution of the specific angular momentum of DM haloes and the cold baryons that comprise the galaxies within.  Study over 2k central galaxies within the reference cosmo hydro sim of the EAGLE project.  Employ a methodology within which the evolutionary history of a system is specified by the time-evolving properties of the Lagrangian particles that define it at z=0.  Find a strong correlation between the evolution of the specific angular momentum of today's stars (cold gas) and that of the inner (whole) DM halo they are associated with.  This link is particularly strong for the stars formed before the epoch of maximum expansion and subsequent collapse of the central DM halo (turnaround).  Spheroids are typically assembled primarily from stars formed prior to turnaround, and are therefore destined to suffer a net loss of angular momentum associated with the strong merging activity during the assembly of the inner DM halo.  Stellar discs retain their specific angular momentum it acquired by tidal torques during the linear growth of the halo.  Since the specific angular momentum loss of the stars is tied to the galaxy's morphology today, it may be possible to use these results to predict, statistically, the assembly history of a all given the morphology of the galaxy it hosts.


1512.02882
Planck intermediate results. XLI. A map of lensing-induced B-modes
Planck Collaboration

The lensing-induced B-mode signal is a valuable probe of the DM distribution integrated back to the last-scattering surface, with a broad kernel that peaks at z~2.  It also constitutes an important contaminant for the extraction of the primary CMB B-modes from inflation.  Combining all-sky coverage and high resolution and sensitivity, Planck provides accurate nearly all-sky measurements of both the polarization E-mode signal and the integrated mass distribution via the reconstruction of the CMB gravitational lensing.  By combining these two data products, produce an all-sky template mass of the secondary CMB B-modes using a real-space algorithm that minimizes the impact of sky masks.  The cross-correlation of this template with an observed (primordial and secondary) B-mode map can be used to measure the lensing B-mode power spectrum at all angular scales.  In particular when cross-correlating with the B-mode contribution directly derived from the Planck polarization maps, obtain lensing-induced B-mode PS measurements at a significance of 12 sigma, which are in agreement with the theoretical expectation derived from the Planck best-fit LCDM model.  This unique nearly all-sky secondary B-mode template, which includes the lensing-induced information from intermediate to small (10<ell<1000) angular scales, is delivered as part of the Planck 2015 public data release.  It will be particularly useful for experiments searching for primordial B-modes, such as BICEP2/Keck Array or LiteBIRD, since it will enable an estimate to be made of the secondary (i.e., lensing) contribution to the measured total CMB B-modes.