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Metallicities of Emission-Line Galaxies from HST ACS PEARS and HST WFC3 ERS Grism Spectroscopy at 0.6 is less than z is less than 2.4
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Author and Affiliation:
Xia, Lifang(Arizona State Univ., United States);
Malhotra, Sangetta(Arizona State Univ., United States);
Rhoads, James(Arizona State Univ., United States);
Pirzkal, Nor(Space Telescope Science Inst., Baltimore, MD, United States);
Straughn, Amber(NASA Goddard Space Flight Center, Greenbelt, MD, United States);
Finkelstein, Steven(Texas A&M Univ., George P. and Cynthis Woods Mitchell Inst. for Fundamental Physics and Astronomy, Dept. of Physics and Astronomy, College Station, TX, United States);
Cohen, Seth(Arizona State Univ., United States);
Kuntschner, Harald(European Southern Observatory, Garching, Germany);
Walsh, Jeremy(European Southern Observatory, Garching, Germany);
Windhorst, Rogier A.(Arizona State Univ., United States);
O'Connell, Robert(Virginia Univ., Dept. of Astronomy, Charlottesville, VA, United States);
Kuemmel, Martin(European Southern Observatory, Garching, Germany)
Abstract: Galaxies selected on the basis of their emission line strength. show low metallicities, regardless of their redshifts. We conclude this from a sample of faint galaxies at redshifts between 0.6 < z < 2.4, selected by their prominent emission lines in low resolution grism spectra in the optiCa.i with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) and in the near-infrared using Wide-Field Camera 3 (WFC3). Using a sample of 11 emission line galaxies (ELGs) at 0.6 < z < 2.4 with luminosities of -22 approx < MB approx -19 which have [OII], H-Beta, and [OIII] line flux measurements from the combination of two grism spectral surveys, we use the R23 method to derive the gas-phase oxygen abundances: 7.5 <12+log(0/H)<8.5. The galaxy stellar masses are derived using Bayesian based Markov Chain Monte Carlo (pi MC(exp 2)) fitting of their Spectral Energy Distribution (SED), and span the mass range 8.1 < log(M(stellar)/M(solar)) < 10.1. These galaxies show a mass-metal1icity (M-L) and Luminosity-Metallicity (LZ) relation, which is offset by -<J.6 dex in meta1licity at given absolute magnitude and stellar mass relative to the local SDSS galaxies, as well as continuum selected DEEP2 samples at similar redshifts. The emission-line selected galaxies most resemble the local "green peas" galaxies and Lyman-alpha galaxies at z approx = 0.3 and z approx = 2.3 in the M-Z and L-Z relations and their morphologies. The G - M(sub 20) morphology analysis shows that 10 out of 11 show disturbed morphology, even as the star-forming regions are compact. These galaxies may be intrinsically metal poor, being at early stages of formation, or the low metallicities may be due to gas infall and accretion due to mergers.
Publication Date: Jan 01, 2012
Document ID:
20130009903
(Acquired Feb 20, 2013)
Subject Category: ASTRONOMY
Report/Patent Number: GSFC.JA.6649.2012
Document Type: Preprint
Contract/Grant/Task Num: NAS5-26555
Financial Sponsor: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Organization Source: NASA Goddard Space Flight Center; Greenbelt, MD, United States
Description: 24p; In English; Original contains black and white illustrations
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright; Distribution as joint owner in the copyright
NASA Terms: ASTRONOMICAL SPECTROSCOPY; GALACTIC EVOLUTION; GALACTIC MASS; GALAXIES; HUBBLE SPACE TELESCOPE; LUMINOSITY; METALLICITY; MORPHOLOGY; PRISMS; RED SHIFT; SPECTRAL ENERGY DISTRIBUTION; STELLAR MASS; SURVEYS
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