J/ApJ/799/205 [OII] emitting galaxies in the HETDEX survey (Bridge+, 2015)
Physical and morphological properties of [OII] emitting galaxies in the
HETDEX pilot survey.
Bridge J.S., Gronwall C., Ciardullo R., Hagen A., Zeimann G., Malz A.I.,
Acquaviva V., Schneider D.P., Drory N., Gebhardt K., Jogee S.
<Astrophys. J., 799, 205 (2015)>
=2015ApJ...799..205B 2015ApJ...799..205B
ADC_Keywords: Galaxies, spectra ; Morphology ; Surveys ; Redshifts
Keywords: cosmology: observations; galaxies: evolution; galaxies: formation;
galaxies: high-redshift
Abstract:
The Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) pilot
survey identified 284 [OII]λ3727 emitting galaxies in a
169arcmin2 field of sky in the redshift range 0<z<0.57. This line
flux limited sample provides a bridge between studies in the local
universe and higher-redshift [OII] surveys. We present an analysis of
the star formation rates (SFRs) of these galaxies as a function of
stellar mass as determined via spectral energy distribution fitting.
The [OII] emitters fall on the "main sequence" of star-forming
galaxies with SFR decreasing at lower masses and redshifts. However,
the slope of our relation is flatter than that found for most other
samples, a result of the metallicity dependence of the [OII] star
formation rate indicator. The mass-specific SFR is higher for lower
mass objects, supporting the idea that massive galaxies formed more
quickly and efficiently than their lower mass counterparts. This is
confirmed by the fact that the equivalent widths of the [OII] emission
lines trend smaller with larger stellar mass. Examination of the
morphologies of the [OII] emitters reveals that their star formation
is not a result of mergers, and the galaxies' half-light radii do not
indicate evolution of physical sizes.
Description:
The data used here were taken as part of the HETDEX pilot survey (HPS;
Adams et al. 2011, J/ApJS/192/5). HPS utilized the fiber-fed George
and Cynthia Mitchell Spectrograph mounted on the Harlan J. Smith 2.7m
telescope at the McDonald Observatory (spectra from 3500 to 5800Å
at a 5Å FWHM spectral resolution).
Of the 284 [OII] emitters, 30 (∼10%) have X-ray counterparts from
surveys by Chandra and XMM-Newton (Adams et al. 2011, J/ApJS/192/5).
Objects with anomalous [OII] SFRs have been excluded from our analysis
(see section 2).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 30 267 Physical parameters if the [OII] emitters
table4.dat 20 153 Morphological parameters and sizes
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See also:
II/261 : GOODS initial results (Giavalisco+, 2004)
J/ApJ/772/48 : Emission-line galaxies from PEARS. II. (Pirzkal+, 2013)
J/ApJ/744/110 : LAE galaxies between 2.1=<z≤3.1 (Ciardullo+, 2012)
J/ApJ/736/31 : HETDEX pilot survey. II. 1.9<z<3.8 LAEs (Blanc+, 2011)
J/ApJS/192/5 : Emission-line galaxies from HETDEX pilot survey (Adams+, 2011)
J/ApJ/705/639 : Sizes of Lyman alpha emitters at z=3.1 (Bond+, 2009)
J/ApJ/667/79 : Lyα emission-line galaxies at z=3.1 (Gronwall+, 2007)
J/ApJ/659/162 : CAS parameters of 199 nearby galaxies (Taylor-Mager+, 2007)
J/ApJS/172/456 : [OII] emitting gal. in COSMOS + SDF fields (Takahashi+, 2007)
J/AJ/128/163 : Galaxy morphological classification (Lotz+, 2004)
J/AJ/127/2002 : Star Formation Rate of NFGS galaxies (Kewley+, 2004)
J/ApJS/147/1 : Classification of nearby galaxies (Conselice+, 2003)
J/ApJ/481/49 : CFRS XIV. Field galaxies up to z=1 (Hammer+ 1997)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- HPS [1/479] HPS identifier
5- 10 F6.3 [Msun] logM* [7.5/11.8] Log stellar mass
12- 18 F7.4 [Msun/yr] logSFR [-1.1/2.1] Log star formation rate
20- 24 F5.3 mag E(B-V) [0.003/0.9] The (B-V) color excess
26- 30 F5.3 --- z [0.07/0.6] Redshift from Adams et al. 2011
(J/ApJS/192/5)
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- HPS [143/479] HPS identifier
5- 8 F4.2 --- G [0.3/0.7] The Gini coefficient (1)
10- 14 F5.2 --- M20 [-2.5/-0.6] The M20 coefficient (1)
16- 20 F5.3 kpc R50 [0.5/9.4] Half-light radius
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Note (1): The morphology and size of the HPS [OII] emitters are
characterized via the Gini (G) and M20 coefficients (Lotz et al.
2004, J/AJ/128/163). The M20 coefficient is defined as the
second-order moment of the brightest 20% of the flux of a galaxy.
See section 7.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 18-Jun-2015