J/MNRAS/435/2861 Star-forming galaxies in near-IR (Martins+, 2013)
Spectral synthesis of star-forming galaxies in the near-infrared.
Martins L.P., Rodriguez-Ardila A., Diniz S., Riffel R., de Souza R.
<Mon. Not. R. Astron. Soc., 435, 2861-2877 (2013)>
=2013MNRAS.435.2861M 2013MNRAS.435.2861M
ADC_Keywords: Galaxy catalogs ; Infrared sources
Keywords: stars: AGB and post-AGB - galaxies: starburst -
galaxies: stellar content - infrared: galaxies
Abstract:
The near-infrared spectral region is becoming a very useful wavelength
range to detect and quantify the stellar population of galaxies.
Models are developing to predict the contribution of the thermally
pulsating stars on the asymptotic giant branch stars that should
dominate the near-infrared region (NIR) spectra of populations 0.3 to
2Gyr old. When present in a given stellar population, these stars
leave unique signatures that can be used to detect them unambiguously.
However, these models have to be tested in a homogeneous data base of
star-forming galaxies, to check if the results are consistent with
what is found from different wavelength ranges. In this work, we
performed stellar population synthesis on the nuclear and extended
regions of 23 star-forming galaxies to understand how the star
formation tracers in the NIR can be used in practice. The stellar
population synthesis shows that for the galaxies with strong emission
in the NIR, there is an important fraction of young/intermediate
population contributing to the spectra, which is probably the
ionization source in these galaxies. Galaxies that had no emission
lines measured in the NIR were found to have older average ages and
less contribution of young populations. Although the stellar
population synthesis method proved to be very effective to find the
young ionizing population in these galaxies, no clear correlation
between these results and the NIR spectral indexes were found. Thus,
we believe that, in practice, the use of these indexes is still very
limited due to observational limitations.
Description:
The sample used here was presented in Martins et al.
(2013MNRAS.431.1823M 2013MNRAS.431.1823M) and is a subset of the one presented in the
magnitude-limited optical spectroscopic survey of nearby bright
galaxies of Ho, Filippenko & Sargent (1995, Cat. J/ApJS/98/477,
hereafter HO95). These galaxies are sources defined by Ho, Filippenko
& Sargent (1997, Cat. J/ApJS/112/315, hereafter HO97) as those
composed of 'nuclei dominated by emission lines from regions of active
star formation (HII or starburst nuclei)'. In addition, five
galaxies, classified as non-star forming in the optical, dominated by
old stellar population and with no detected emission lines, were
included as a control sample.
All spectra were obtained at the NASA 3m Infrared Telescope Facility
(IRTF) in two observing runs (2007 and 2008) - the same data from
Martins et al. (2013MNRAS.431.1823M 2013MNRAS.431.1823M).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 28 Sample details
table2.dat 86 85 Results of the NIR stellar population synthesis
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See also:
J/ApJS/98/477 : Optical spectral atlas of Seyfert nuclei (Ho+ 1995)
J/ApJS/112/315 : Spectroscopic parameters of Seyfert nuclei (Ho+ 1997)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Galaxy Galaxy (1)
10- 16 F7.4 --- z Redshift
18- 24 A7 --- Ap Apertures
26 A1 --- Class [HN] Classification: H=HII galaxy, N=normal
28- 31 F4.2 0.1nm W(Gband) ?=- G-band equivalent width
33- 38 F6.2 [mW/m2] logF(Ha) ?=- Hα flux (erg/cm2/s)
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Note (1): References: Ho et al., 1995, J/ApJS/98/477,
Kennicutt (1988ApJ...334..144K 1988ApJ...334..144K), Coziol et al. (1998ApJS..119..239C 1998ApJS..119..239C).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Galaxy Galaxy name
10- 12 A3 --- Ap Aperture (2)
14- 15 I2 % Xy [0/64] Young (t≤5x107yr) population component
17- 19 I3 % Xi [0/100] Intermediate (1x108≤t≤2x109yr)
population component
21- 23 I3 % Xo [0/100] Old (t>2x109yr) population component
25- 30 F6.3 mag AV Extinction
32- 35 F4.2 [yr] log(t) Average age log(tav)
37- 41 F5.3 --- Z Average metallicity Zav
43- 50 E8.3 Msun M* Stellar mass
52- 59 E8.3 Msun Mini Mass processed in stars during Galaxy lifetime
61- 68 E8.3 Msun/yr SFR100 [0/2.1] Star formation rate in the last 100#Myr
70- 74 F5.2 --- chi2 [0.5/11.1] Reduced χ2 value
76- 80 F5.2 % adev Percentage mean deviation |O-M|/O over all
fitted pixels
82- 86 F5.2 arcsec d Distance of the aperture to the nucleus
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Note (2): Apertures are: "nuc" for nucleus, S1-S3 are south to the nucleus,
and N1-N4 are north to the nucleus. The numbers following the letter
'N' or 'S' increase with the distance to the centre.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 10-Oct-2014