Day 1112

Wednesday.

1606.08448
Relative likelihood for life a s function of cosmic time
Loeb, Batista, Sloan

Is life most likely to emerge at the preset cosmic time near a star like the Sun?  Address this question by calculating the relative formation probability per unit time of habitable Earth-like planets within a fixed comoving volume of the Universe, dP(t)/dt, starting from the first stars and continuing to the distant cosmic future.  Conservatively restrict the attention to the context of "life as we know it" and the standard cosmological model, LCDM.  Find that unless habitability around low mass stars is suppressed, life is most likely to exist near 0.1 Msun stars 10 trillion years from now.  Spectroscopic searches for biosignatures in the atmospheres of transiting Earth-mass planets around low mass stars will determine whether resent-day life is indeed premature or typical from a cosmic perspective.


1606.08841
Cross-correlating Planck CMB lensing with SDSS: Lensing-lensing and galaxy-lensing cross-correlations
Singh, Mandelbaum, Brownstein

Present first results from cross-correlating Planck CMB lensing maps with SDSS galaxy lensing shape catalog and BOSS galaxy catalogs.  For galaxy position vs CMB lensing cross-correlations, measure the convergence signal around the galaxies in configuration space, using the BOSS LOWZ (z~0.40) and CMASS (z~0.57) samples.  With fixed Planck 2015 cosmology, doing a joint fit with the galaxy clustering measurement, for the LOWZ (CMASS) sample find a galaxy bias b_g=0.175±0.04 (1.95±0.02) and galaxy-matter cross-correlation coefficient r_cc=1.0±0.2 (0.8±0.1) using 20<r_p<70 Mpc/h, consistent with results from gg lensing.  Using the same scales and including the gglensing measurements, constrain Omega_m=0.284±0.024 and relative calibration bias between the CMB lensing and galaxy lensing to be b_gamma=0.82±0.15.  The combination of galaxy lensing and CMB lensing also allows to measure the cosmological distance ratios (with z_l~0.3, z_s~0.5) R= (D_s D_l,*) / (D_* D_L,s) = 2.68±0.29, consistent with predictions from the Planck 2015 cosmology (R=2.35).  Detect the galaxy position-CMB convergence cross-correlation at small scales, r_p<1 Mpc/h and find consistency with lensing by NFW halos of mass M_h~1e13 Msun/h.  Finally, measure the CMB lensing-galaxy shear cross-correlation, finding an amplitude of A=0.76±0.23 (z_eff=0.35, theta<2deg) with respect to Planck 2015 LCDM predictions (1sigma-level consistency).  Do not find evidence for relative systematics between the CMB and SDSS galaxy lensing.