J/ApJ/719/1191 Mid-IR indicators of SF and AGN in galaxies (Treyer+, 2010)
Mid-infrared spectral indicators of star formation and active galactic nucleus
activity in normal galaxies.
Treyer M., Schiminovich D., Johnson B.D., O'Dowd M., Martin C.D., Wyder T.,
Charlot S., Heckman T., Martins L., Seibert M., van der Hulst J.M.
<Astrophys. J., 719, 1191-1211 (2010)>
=2010ApJ...719.1191T 2010ApJ...719.1191T
ADC_Keywords: Galaxies, IR ; Spectra, infrared ; Line Profiles ;
Interstellar medium ; Equivalent widths
Keywords: galaxies: active - galaxies: ISM - galaxies: star formation -
infrared: galaxies - surveys
Abstract:
We investigate the use of mid-infrared (MIR) polycyclic aromatic
hydrocarbon (PAH) bands, the continuum, and emission lines as probes
of star formation (SF) and active galactic nucleus (AGN) activity in a
sample of 100 "normal" and local (z∼0.1) emission-line galaxies. The
MIR spectra were obtained with the Spitzer Space Telescope Infrared
Spectrograph as part of the Spitzer-SDSS-GALEX Spectroscopic Survey
(SSGSS), which includes multi-wavelength photometry from the
ultraviolet to the far-infrared and optical spectroscopy. The
continuum and features were extracted using PAHFIT, a decomposition
code which we find to yield PAH equivalent widths (EWs) up to ∼30
times larger than the commonly used spline methods. Despite the lack
of extreme objects in our sample (such as strong AGNs, low-metallicity
galaxies, or ULIRGs), we find significant variations in PAH,
continuum, and emission-line properties, and systematic trends between
these MIR properties and optically derived physical properties, such
as age, metallicity, and radiation field hardness. We revisit the
diagnostic diagram relating PAH EWs and [NeII]12.8um/[OIV]25.9um line
ratios and find it to be in much better agreement with the standard
optical SF/AGN classification than when spline decompositions are
used, while also potentially revealing obscured AGNs.
Description:
The Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) is an MIR
spectroscopic survey of 101 local star-forming galaxies using the IRS
on board the Spitzer satellite. The sample is drawn from the Lockman
Hole region which has been extensively surveyed at multiple
wavelengths. A detailed description of the data acquisition and
reduction can be found in O'Dowd et al. (2011, Cat. J/ApJ/741/79).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 101 82 Absorption corrected continuum, PAH and line fluxes
derived from the PAHFIT decompositions
table2.dat 20 82 Aperture corrections in magnitudes
table3.dat 56 82 PAH equivalent widths
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See also:
J/ApJ/741/79 : The Spitzer-SDSS-GALEX Spectroscopic Survey (O'Dowd+, 2011)
J/ApJ/705/885 : PAH in galaxies at z∼0.1 (O'Dowd+, 2009)
J/A+A/507/713 : Galaxies with strong PAH emission (Haas+, 2009)
J/ApJ/686/127 : Starbursts luminosities based on PAH (Weedman+, 2008)
http://www.astro.columbia.edu/ssgss : SSGSS home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- SSGSS [1/99] Identification number
5- 9 F5.2 10+10Jy.Hz C8 Absorption corrected 8um continuum flux (1)
11- 14 F4.2 10+10Jy.Hz e_C8 Uncertainty in C8
16- 20 F5.2 10+10Jy.Hz C16 Absorption corrected 16um continuum flux (1)
22- 25 F4.2 10+10Jy.Hz e_C16 Uncertainty in C16
27- 31 F5.2 10+10Jy.Hz C24 Absorption corrected 24um continuum flux (1)
33- 37 F5.2 10+10Jy.Hz e_C24 Uncertainty in C24
39- 43 F5.2 10+10Jy.Hz P7.7 PAH 7.7 micron flux
45- 48 F4.2 10+10Jy.Hz e_P7.7 Uncertainty in PAH7.7
50- 53 F4.2 10+10Jy.Hz P17 PAH 17 micron flux
55- 58 F4.2 10+10Jy.Hz e_P17 Uncertainty in PAH17
60- 64 F5.2 10+8.Jy.Hz L12.8 The [NeII] 12.8 micron flux
66- 69 F4.2 10+8.Jy.Hz e_L12.8 Uncertainty in L12.8
71- 74 F4.2 10+8.Jy.Hz L15.5 The [NeIII] 15.5 micron line flux
76- 79 F4.2 10+8.Jy.Hz e_L15.5 Uncertainty in L15.5
81- 84 F4.2 10+8.Jy.Hz L25.9 The [OIV] 25.9 micron line flux
86- 90 F5.2 10+8.Jy.Hz e_L25.9 Uncertainty in L25.9
92- 96 F5.2 10+8.Jy.Hz LH2 Sum of H2S(0) to S(2) lines flux
98-101 F4.2 10+8.Jy.Hz e_LH2 Uncertainty in LH2
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Note (1): Defined as νFν.
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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- 3 I3 --- SSGSS [1/99] Identification number
5- 8 F4.2 mag AC8 Spitzer/IRAC 8 micron aperture correction
10- 14 F5.2 mag AC16 Spitzer/IRS 16 micron aperture correction
16- 20 F5.2 mag AC24 Spitzer/MIPS 24 micron aperture correction
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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- 3 I3 --- SSGSS [1/99] Identification number
5- 9 F5.2 um W6.2 PAH 6.2 micron feature equivalent width
11- 14 F4.2 um e_W6.2 Uncertainty in W6.2
16- 20 F5.2 um W7.7 PAH 7.7 micron feature equivalent width
22- 26 F5.2 um e_W7.7 Uncertainty in W7.7
28- 31 F4.2 um W8.6 PAH 8.6 micron feature equivalent width
33- 36 F4.2 um e_W8.6 Uncertainty in W8.6
38- 41 F4.2 um W11.3 PAH 11.3 micron feature equivalent width
43- 46 F4.2 um e_W11.3 Uncertainty in W11.3
48- 51 F4.2 um W17 PAH 17 micron feature equivalent width
53- 56 F4.2 um e_W17 Uncertainty in W17
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 19-Jun-2012