Nelson D. Padilla

Lyα-Emitting Galaxies at z = 3.1: L* Progenitors Experiencing Rapid Star Formation

We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample of 162 Lyα-emitting (LAE) galaxies at z 3.1 discovered in deep narrowband MUSYC imaging of the Extended Chandra Deep Field-South. LAEs were selected to have observed frame equivalent widths >80 A and emission line fluxes >1.5 × 10-17 ergs cm-2 s-1. Only 1% of our LAE sample appears to host AGNs. The LAEs exhibit a moderate spatial correlation length of r0 = 3.6 Mpc, corresponding to a bias factor b = 1.7, which implies median dark matter halo masses of log10 Mmed = 10.9 M☉. Comparing the number density of LAEs, 1.5 ± 0.3 × 10-3 Mpc-3, with the number density of these halos finds a mean halo occupation ~1%-10%. The evolution of galaxy bias with redshift implies that most z = 3.1 LAEs evolve into present-day galaxies with L 3 galaxy populations typically evolve into more massive galaxies. Halo merger trees show that z = 0 descendants occupy halos with a wide range of masses, with a median descendant mass close to that of L*. Only 30% of LAEs have sufficient stellar mass (>~3 × 109 M☉) to yield detections in deep Spitzer IRAC imaging. A two-population SED fit to the stacked UBVRIzJK+[3.6, 4.5, 5.6, 8.0] μm fluxes of the IRAC-undetected objects finds that the typical LAE has low stellar mass (1.0 × 109 M☉), moderate star formation rate (2 ± 1 M☉ yr-1), a young component age of 20 Myr, and little dust (AV < 0.2). The best-fit model has 20% of the mass in the young stellar component, but models without evolved stars are also allowed.

Cosmological parameters from cosmic microwave background measurements and the final 2dF Galaxy Redshift Survey power spectrum

We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and temperature-polarization cross-correlation of the cosmic microwave background radiation. We analyse a range of parameter sets and priors, allowing for massive neutrinos, curvature, tensors and general dark energy models. In all cases, the combination of datasets tightens the constraints, with the most dramatic improvements found for the density of dark matter and the energy-density of dark energy. If we assume a flat universe, we find a matter density parameter of

Effects of AGN feedback on ΛCDM galaxies

\Omega_{\rm m}=0.237 \pm 0.020

The shapes of galaxies in the Sloan Digital Sky Survey

, a baryon density parameter of

Angular momentum-large-scale structure alignments in ΛCDM models and the SDSS

\Omega_{\rm b} = 0.041 \pm 0.002

THE EVOLUTION OF Lyα-EMITTING GALAXIES BETWEEN z = 2.1 AND z = 3.1

, a Hubble constant of

Ly alpha-EMITTING GALAXIES AT z=2.1 : STELLAR MASSES, DUST, AND STAR FORMATION HISTORIES FROM SPECTRAL ENERGY DISTRIBUTION FITTING

H_{0}=74\pm2 {\rm kms}^{-1}{\rm Mpc}^{-1}

Testing gravity using cosmic voids

, a linear theory matter fluctuation amplitude of

The 2dF Galaxy Redshift Survey: the clustering of galaxy groups

\sigma_{8}=0.77\pm0.05

Ground-based and Airborne Instrumentation for Astronomy IV

and a scalar spectral index of