J/ApJ/671/323 Spitzer Spectra of a 10mJy galaxy sample (Houck+, 2007)
Spitzer spectra of a 10mJy galaxy sample and the star formation rate in the
Local universe.
Houck J.R., Weedman D.W., Le Floc'h E., Hao L.
<Astrophys. J., 671, 323-332 (2007)>
=2007ApJ...671..323H 2007ApJ...671..323H
ADC_Keywords: Galaxies, IR ; Spectra, infrared
Keywords: dust, extinction - infrared: galaxies - galaxies: starburst
Abstract:
A complete flux-limited sample of 50 galaxies is presented having
fν(24um)>10mJy, chosen from a survey with MIPS on Spitzer of
8.2deg2 in the NOAO Deep Wide-Field Survey (NDWFS) region in Bootes.
Spectra obtained with the low-resolution modules of IRS on Spitzer are
described for 36 galaxies in this sample; 25 show strong PAH emission
features characteristic of starbursts, and 11 show silicate absorption
or emission, emission lines, or featureless spectra characteristic of
AGNs. Infrared or optical spectral classifications are available for
48 of the entire sample of 50; 33 galaxies are classified as
starbursts and 15 as AGNs.
Description:
Of the 50 sources, we describe new IRS results for 26 sources in our
program and 10 from the Spitzer public archive (program 20113; H.
Dole, in preparation). Adding optical spectral classifications from
the Sloan Digital Sky Survey (SDSS) allows the spectroscopic
classification of the sources as starbursts or AGNs for 48 of the 50
sources in the complete sample. Spitzer spectroscopic observations
were made with the IRS3 Short-Low module in orders 1 and 2 (SL1 and
SL2) and with the Long-Low module in orders 1 and 2 (LL1 and LL2).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 50 The Bootes 10mJy sample
notes.dat 56 17 Individual notes
table3.dat 103 25 Redshifts, luminosities, and star formation
rates of PAH sources
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- [HWL2007] Sequential number
4- 8 A5 --- --- [SST24]
10- 28 A19 --- SST24 Source name (JHHMMSS.ss+DDMMSS.s), in Simbad
[HWL2007] SST24 JHHMMSS.ss+DDMMSS.s (1)
30- 37 I8 --- AOR ? AOR number (observation number in the
Spitzer archive)
39- 47 A9 --- Prog Program number(s)
49- 51 I3 s expSL ? Total integration time in IRS Short-Low
orders 1 and 2
53- 55 I3 s expLL ? Total integration time in IRS Long-Low
orders 1 and 2
57- 61 F5.1 mJy F24um Flux at 24um (2)
62 A1 --- n_F24um [r] Note on F24um (3)
64- 67 F4.1 mJy F24um2 ? Flux at 24um measured independently from
the extracted IRS spectra (2)
68 A1 --- f_F24um [g] Note on F24um (3)
69 A1 --- l_F70um Limit flag on 70um
70- 73 I4 mJy F70um ? Flux at 70um (4)
74 A1 --- u_F70um [?] Uncertainty flag on F70um
75 A1 --- n_F70um [r] Note on F70um (2)
77- 98 A22 --- Class Classification of IRS spectrum (5)
100 A1 --- n_Class [*] Note on Class, in notes.dat file
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Note (1): SST24 source name derives from discovery with the MIPS 24um
images; coordinates listed are J2000.0 24um positions with typical
3σ uncertainty of ±1.2".
Note (2): Values of fν(24um) are for an unresolved point source measured
from MIPS images, except that source noted by (r). The mean difference
of ±4% between IRS and MIPS values gives an estimate of uncertainties
in results
Note (3): Notes as follows:
g = Spiral galaxy and liner NGC 5656, with SDSS z=0.01055
r = sources resolved in the same galaxy in the 24um or 70um image,
and the flux listed is the total flux for all components.
Note (4): Values of fν(70um) are for an unresolved point source,
measured from MIPS images; fluxes are uncertain for sources 13 and 14
because these are two closely interacting galaxies. Sources without
measured fν(70um) are outside of the field of view for the 70um survey.
Note (5): Classification of IRS spectrum, whether showing PAH emission,
emission lines, absorption by the 9.7um Si feature, emission by the
9.7um silicate feature, or no features; numerical value gives
classification according to scheme of Spoon et al. (2007ApJ...654L..49S 2007ApJ...654L..49S)
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Byte-by-byte Description of file: notes.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- [HWL2007] Source number
4- 56 A53 --- Note Note
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- [HWL2007] Sequential number
4- 12 A9 --- Source Source name (HHMM+DDMM) (1)
14- 19 F6.4 --- z IRS redshift (3)
21- 26 F6.4 --- z2 ?=- SDSS redshift (2)
28- 42 A15 --- Class SDSS class
43- 46 I4 Mpc DL Luminosity distance
48- 51 F4.2 um EW6.2um Equivalent width at 6.2um (4)
53- 56 F4.2 um e_EW6.2um rms uncertainty on EW6.2um
58- 61 F4.1 mJy F7.7um Flux density at peak of 7.7um feature
63- 66 F4.1 mJy F7.7um2 Flux density at peak of 7.7um feature
after subtraction of underlying
continuum at 7.7um
68- 72 F5.2 [10-7W] log(nuLnu) Luminosity at 7.7um in source
rest frame (5)
74- 78 F5.2 [solLum] log(LIR) Infrared luminosity
80- 85 F6.2 Msun/yr SFR Stellar formation rate (6)
87- 90 F4.2 Msun/yr SFR2 ? Second value of stellar formation
rate (7)
92- 98 F7.4 10-5Mpc-3 Dens Space density (8)
100-103 F4.1 10-5Msun/yr/Mpc3 SFRdens Stellar formation rate density (9)
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Note (1): Source name is truncated name from Table 1.
Note (2): SDSS redshifts are from optical spectra.
Note (3): IRS redshifts are determined from PAH emission features, assuming
rest wavelengths of 6.2, 7.7, 8.6, and 11.3um; mean difference between
SDSS and IRS redshifts of 0.0012 is estimate of uncertainty in IRS
redshift.
Note (4): Equivalent widths listed (EW) are in the observed frame;
equivalent widths in the rest frame are EW/(1+z).
Note (5): determined from peak flux density of 7.7um feature without
continuum subtraction.
Note (6): SFR for this source as determined from relation
log(SFR)=log[nuLnu(7.7um)]-42.57.
Note (7): SFR that would be derived using the f(Hα) for KISS sources
and the relation log(SFR)=log[L(Hα)]-41.1, with no correction for
extinction.
Note (8): Space density for this source determined from inverse of comoving
volume Vmax which source could occupy and remain within sample
fν(24um)>10mJy; luminosity distances and comoving volumes
determined by E.L. Wright, for H0=71km/s/Mpc, ΩM=0.27, and
ΩΛ=0.73 (http://www.astro.ucla.edu/~wright/CosmoCalc.html)
Note (9): SFR density produced by this source as determined from
νLν(7.7um).
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Feb-2010