A comprehensive view of a strongly lensed planck-associated submillimeter galaxy
Astrophysical Journal 753:2 (2012)
Abstract:
We present high-resolution maps of stars, dust, and molecular gas in a strongly lensed submillimeter galaxy (SMG) at z = 3.259. HATLAS J114637.9-001132 is selected from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) as a strong lens candidate mainly based on its unusually high 500 μm flux density (300mJy). It is the only high-redshift Planck detection in the 130deg2 H-ATLAS Phase-I area. Keck Adaptive Optics images reveal a quadruply imaged galaxy in the K band while the Submillimeter Array and the Jansky Very Large Array show doubly imaged 880 μm and CO(1→0) sources, indicating differentiated distributions of the various components in the galaxy. In the source plane, the stars reside in three major kpc-scale clumps extended over 1.6kpc, the dust in a compact (∼1 kpc) region ∼3kpc north of the stars, and the cold molecular gas in an extended (∼7kpc) disk ∼5kpc northeast of the stars. The emissions from the stars, dust, and gas are magnified by ∼17, ∼8, and ∼7times, respectively, by four lensing galaxies at z ∼1. Intrinsically, the lensed galaxy is a warm (T dust ∼40-65 K), hyper-luminous (L IR ∼ 1.7 × 1013 L star formation rate (SFR) ∼2000 M yr-1), gas-rich (M gas/M baryon 70%), young (M stellar/SFR 20Myr), and short-lived (M gas/SFR 40Myr) starburst. With physical properties similar to unlensed z > 2 SMGs, HATLAS J114637.9-001132 offers a detailed view of a typical SMG through a powerful cosmic microscope. © 2012. The American Astronomical Society. All rights reserved..EVIDENCE FOR A MILD STEEPENING AND BOTTOM-HEAVY INITIAL MASS FUNCTION IN MASSIVE GALAXIES FROM SODIUM AND TITANIUM-OXIDE INDICATORS
The Astrophysical Journal Letters American Astronomical Society 753:2 (2012) l32
Supernova simulations and strategies for the dark energy survey
Astrophysical Journal 753:2 (2012)
Abstract:
We present an analysis of supernova light curves simulated for the upcoming Dark Energy Survey (DES) supernova search. The simulations employ a code suite that generates and fits realistic light curves in order to obtain distance modulus/redshift pairs that are passed to a cosmology fitter. We investigated several different survey strategies including field selection, supernova selection biases, and photometric redshift measurements. Using the results of this study, we chose a 30deg2 search area in the griz filter set. We forecast (1) that this survey will provide a homogeneous sample of up to 4000 TypeIa supernovae in the redshift range 0.05Co-evolution of black hole growth and star formation activity in local luminous infrared galaxies
Proceedings of the 10th Scientific Meeting of the Spanish Astronomical Society - Highlights of Spanish Astrophysics VII, SEA 2012 (2012) 103-114
Abstract:
We use Spitzer spectroscopic and imaging observations to study the co-evolution of black hole (BH) growth and star formation (SF) activity in a complete volume-limited sample of local Luminous Infrared Galaxies (LIRGs). Using a mid-infrared (mid-IR) spectral decomposition method we identify active galactic nuclei (AGN) with Seyfert-like luminosities and relatively small bolometric contributions (median ∼ 5%) in half of the LIRG nuclei. Combining mid-IR and AGN optical detections we obtain a 62% AGN detection rate in local LIRGs. We combine gas velocity dispersions of spectrally resolved [Ne iii]15.56 µm and [O iii]λ5007Å lines and literature stellar velocity dispersions , and we obtain typical BH masses of 3 ×107 M☉ for local LIRGs. We find that the ratios of nuclear and integrated SF rates (SFR) to BH accretion rates are higher in local LIRGs than in optically selected Seyferts. We interpret our results in a scenario where local LIRGs with an AGN represent an early phase of the (possibly episodic) growth of BHs in massive spiral galaxies with high SFR, not necessarily associated with a major merger event.A population of dust-rich quasars at z ∼ 1.5
Astrophysical Journal 753:1 (2012)