Day 1499

Friday.

1811.05982
The shapes of the rotation curves of star-forming galaxies over the last $\approx$ 10 Gyr
Tiley, et al

Analyse maps of the spatially-resolved nebular emission of ~1500 SF galaxies at z~0.6-2.2 from deep KMOS and MUSE observations to measure the average shape of their rotation curves.  Use these to test claims for declining rotation curves at large radii and galaxies at z~1-2 that have been interpreted as evidence for an absence of dark matter.  Show that the shape of the average rotation curves, and the extend to which they decline beyond their peak velocities, depends upon the normalization prescription used to construct the average curve.  Normalising in size by the galaxy stellar disk-scale length R_d, construct stacked position-velocity diagrams that trace the average galaxy rotation curve out to 6R_d (~13 kpc, on average).  Combining these curves with average HI rotation curves for local systems, investigate how the shapes of galaxy rotation curves evolve over ~10 Gyr.  The average rotation curve for galaxies binned in stellar mass, stellar surface mass density and/or redshift is approximately flat, or continues to rise, out to at least 6R_d.  Find a correlation between the outer slopes of galaxies' rotation curves and their stellar mass surface densities, with the higher surface density systems exhibiting flatter or less steeply rising rotation curves.  Drawing comparisons with hydro sims, show that the average shapes of the rotation curves for the sample of massive, SF galaxies at z~0-2.2 are consistent with those expected from LCDM theory an imply DM fractions within 6R_d of at least 60%.


1811.06408
SDSS-IV MaNGA: Signatures of halo assembly in kinematically misaligned galaxies
Duckworth, et al

Investigate the relationship of kinematically misaligned galaxies with their large-scale environment, in the context of halo assembly bias.  According to numerical simulations, halo age at fixed halo mass is intrinsically linked to the large-scale tidal environment created by the cosmic web.  Investigate the relationship between distances to various cosmic web features and present-time gas accretion rate.  Select a sub-sample of ~900 central galaxies from the MaNGA survey with defined global position angles (PA; angle at which velocity change is greatest) for their stellar and Alpha gas components up to a minimum of 1.5 R_eff.  Split the sample by misalignment between the gas and stars as defined by the difference in their PA.  For each central galaxy, find its distance to nodes and filaments within the cosmic web, and estimate the host halo's age using the central stellar mass to total halo mass ratio M*/Mh.  Also construct halo occupation distributions using a background subtraction technique for galaxy groups split using the central galaxy's kinematic misalignment.  Find, at fixed halo mass, no statistical difference in these properties between the kinematically aligned and misaligned galaxies.  Suggest that the lack of correlation could be indicative of cooling flows from the hot halo playing a far larger role than 'cold mode' accretion from the cosmic web or a demonstration that the spatial extent of current large-scale internal field unit (IFU) surveys hold little information about large-scale environment extractable through this method.


1811.06499
Cosmological constraints from galaxy-lensing cross correlations using BOSS galaxies with SDSS and CMB lensing
Singh, Mandelbaum, Seljak, Rodriquez-Torres, Solar

Present cosmological parameter constraints based on a joint modeling of galaxy-lensing cross correlations and galaxy clustering measurements in the SDSS, marginalizing over small-scale modeling uncertainties using mock galaxy catalogs, without explicit modeling of galaxy bias.  Show that the modeling method is robust to the impact of different choices for how galaxies occupy DM haloes and to the impact of baryonic physics (at the ~2% level in cosmo params) and test for the impact of covariance on the likelihood analysis and of the survey window function on the theory computations.  Applying the results to the measurements using galaxy sample from BOSS and lensing measurements using shear from SDSS galaxies and CMB lensing from Planck, with conservative scale cuts, obtain S_8==(sigma8/0.8228)^0.8 (Omega_m/0.307)^0.6=0.85±0.05 (stat) using LOWZ x SDSS galaxy lensing, and S_8=0.91±0.1 (stat) using combination of LOWZ and CMASS x Planck CMB lensing.  Estimate the systematic uncertainty in the gg lensing measurements to be ~6% (dominated by photometric z uncertainties) and in the galaxy-CMB lensing measurements to be ~3%, from small scale modeling uncertainties including baryonic physics.