J/ApJS/173/471 Keck DEIMOS spectroscopy of GALEX sources (Mallery+, 2007)
Keck DEIMOS spectroscopy of a GALEX UV-selected sample from the medium imaging
survey.
Mallery R.P., Rich R.M., Salim S., Small T., Charlot S., Seibert M.,
Wyder T., Barlow T.A., Forster K., Friedman P.G., Martin D.C., Morrissey P.,
Neff S.G., Schiminovich D., Bianchi L., Donas J., Heckman T.M., Lee Y.-W.,
Madore B.F., Milliard B., Szalay A.S., Welsh B.Y., Yi S.
<Astrophys. J. Suppl. Ser., 173, 471-481 (2007)>
=2007ApJS..173..471M 2007ApJS..173..471M (SIMBAD/NED BibCode)
ADC_Keywords: Equivalent widths ; Galaxies, spectra ; Redshifts ; Ultraviolet
Keywords: galaxies: active - galaxies: high-redshift - galaxies: starburst -
ultraviolet: galaxies
Abstract:
We report results from a pilot program to obtain spectroscopy for
objects detected in the Galaxy Evolution Explorer (GALEX) Medium
Imaging Survey (MIS). Our study examines the properties of galaxies
detected by GALEX fainter than the Sloan Digital Sky Survey (SDSS)
spectroscopic survey. This is the first study to extend the techniques
of Salim and coworkers to estimate stellar masses, star formation
rates (SFRs), and the b (star formation history) parameter for
star-forming galaxies out to z∼0.7. We obtain redshifts for 50 GALEX
MIS sources reaching NUV=23.9 (AB mag) having counterparts in the SDSS
Data Release 4 (DR4). Of our sample, 43 are star-forming galaxies with
z<0.7, 3 have emission-line ratios indicative of active galactic
nuclei with z<0.7, and 4 objects with z>1 are QSOs, 3 of which are not
previously cataloged. We compare our sample to a much larger sample of
∼50000 matched GALEX/SDSS galaxies with SDSS spectroscopy; while our
survey is shallow, the optical counterparts to our sources reach ∼3mag
fainter in SDSS r than the SDSS spectroscopic sample. We use
emission-line diagnostics for the galaxies to determine that the
sample contains mostly star-forming galaxies.
Description:
Sources detected by GALEX using the DEIMOS multiobject spectrograph
(Faber et al., 2003SPIE.4841.1657F 2003SPIE.4841.1657F) on the Keck II telescope and optical
photometry obtained from SDSS Data Release 4 (DR4; Abazajian et al.,
2004AJ....128..502A 2004AJ....128..502A).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 100 41 Redshifts, Equivalent Widths, and Line Ratios
for the Spectroscopic Sample
table2.dat 86 50 Galaxies, Redshifts, Colors and Derived Parameters
--------------------------------------------------------------------------------
See also:
J/AJ/133/1780 : GALEX/SDSS quasar catalog (Trammell+, 2007)
J/ApJS/173/185 : GALEX ultraviolet atlas of nearby galaxies (Gil de Paz+, 2007)
J/ApJS/173/441 : UV-Luminous galaxies discovered by GALEX (Hoopes+, 2007)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- objID SDSS Object Identification number
21- 25 F5.3 --- z Redshift
27- 30 F4.2 0.1nm EWOII ?=- The [OII] (3727Å) equivalent width
32- 35 F4.2 0.1nm e_EWOII ? Error on [OII] EW
37- 40 F4.2 0.1nm EWHb ?=- The Hβ equivalent width
42- 45 F4.2 0.1nm e_EWHb ? Error on Hβ EW
47- 50 F4.2 0.1nm EWOIII ?=- The [OIII] (5007Å) EW
52- 55 F4.2 0.1nm e_EWOIII ? Error on [OIII] EW
57- 61 F5.2 0.1nm EWHa ?=- The Hα equivalent width
63- 67 F5.2 0.1nm e_EWHa ? Error on Hα EW
69- 72 F4.2 0.1nm EWNII ?=- The [NII] (6584Å) equivalent width
74- 78 F5.2 0.1nm e_EWNII ? Error on [NII] EW
80- 84 F5.2 --- OIII/Hb ?=- Flux ratio of [OIII](5007Å)/Hβ
86- 89 F4.2 --- e_OIII/Hb ? Error on flux ratio of [OIII]/Hβ
91- 94 F4.2 --- NII/Ha ?=- Flux ratio of [NII](6584Å)/Hα
96-100 F5.3 --- e_NII/Ha ? Error on flux ratio of [NII]/Hα
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- objID SDSS Object Identification number
21- 25 F5.3 --- z Redshift
27- 28 I2 h RAh Hour of Right Ascension (J2000)
30- 31 I2 min RAm Minute of Right Ascension (J2000)
33- 38 F6.3 s RAs Second of Right Ascension (J2000)
39 A1 --- DE- Sign of the Declination (J2000)
40- 41 I2 deg DEd Degree of Declination (J2000)
43- 44 I2 arcmin DEm Arcminute of Declination (J2000)
46- 50 F5.2 arcsec DEs Arcsecond of Declination (J2000)
52- 56 F5.2 mag FUV ?=- Far ultraviolet magnitude (1344-1786Å)
58- 62 F5.2 mag NUV Near Ultraviolet magnitude (1771-2831Å)
64- 68 F5.2 mag NUV-r NUV-r color index
70- 74 F5.2 [solMass] Mass ?=- log of the present-day Stellar Mass of
the galaxy
76- 80 F5.2 [solMass/yr] SFR ?=- log of the current Star Formation Rate
(SFR) average over the past 100Myr
82- 86 F5.2 [---] b ?=- log of the Scalo b-parameter defined as
the ratio of the current SFR to the past
time-averaged SFR (averaged over the
estimated age, not Hubble time)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 27-May-2009