J/ApJ/741/32 Spatial extent of (U)LIRGs in the MIR. II. (Diaz-Santos+, 2011)
The spatial extent of (U)LIRGs in the mid-infrared.
II. Feature emission.
Diaz-Santos T., Charmandaris V., Armus L., Stierwalt S., Haan S.,
Mazzarella J.M., Howell J.H., Veilleux S., Murphy E.J., Petric A.O.,
Appleton P., Evans A.S., Sanders D.B., Surace J.A.
<Astrophys. J., 741, 32 (2011)>
=2011ApJ...741...32D 2011ApJ...741...32D
ADC_Keywords: Galaxies, IR ; Active gal. nuclei ; Spectra, infrared
Keywords: galaxies: active - galaxies: evolution - galaxies: interactions -
galaxies: starburst - infrared: galaxies
Abstract:
We present results from the second part of our analysis of the
extended mid-infrared (MIR) emission of the GOALS sample based on
5-14um low-resolution spectra obtained with the Infrared Spectrograph
on Spitzer. We calculate the fraction of extended emission (FEE) as a
function of wavelength for all galaxies in the sample, FEEλ,
defined as the fraction of the emission that originates outside of the
unresolved central component of a source, and spatially separate the
MIR spectrum of a galaxy into its nuclear and extended components. We
find that the [NeII]12.81um emission line is as compact as the hot
dust MIR continuum, while the polycyclic aromatic hydrocarbon (PAH)
emission is more extended. In addition, the 6.2 and 7.7um PAH emission
is more compact than that of the 11.3um PAH, which is consistent with
the formers being enhanced in a more ionized medium. The presence of
an active galactic nucleus (AGN) or a powerful nuclear starburst
increases the compactness and the luminosity surface density of the
hot dust MIR continuum, but has a negligible effect on the spatial
extent of the PAH emission on kpc-scales. Furthermore, it appears that
both processes, AGN and/or nuclear starburst, are indistinguishable in
terms of how they modify the integrated PAH-to-continuum ratio of the
FEE in (ultra)luminous infrared galaxies ((U)LIRGs). Globally, the
5-14um spectra of the extended emission component are homogeneous for
all galaxies in the GOALS sample.
Description:
The sample we analyze is the Great Observatories All-Sky LIRG Survey
(GOALS; Armus et al. 2009PASP..121..559A 2009PASP..121..559A).
Haan et al. (2011AJ....141..100H 2011AJ....141..100H) present a thorough analysis of the
nuclear structure of the galaxy sample using high spatial resolution
NIR and optical images obtained with the Hubble Space Telescope.
Out of the 291 galaxies (202 systems) included in the GOALS sample, a
total of 221 are used for this study, 200 LIRGs and 21 ULIRGs. All of
them have low-resolution spectroscopic Spitzer/IRS observations in the
5-14um rest-frame wavelength range (angular resolution of IRS is ∼3.6"
at 13.2um)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 221 FEEs (fraction of extended emission) of
various MIR (mid-infrared) features
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See also:
J/A+A/546/A64 : H & K-band stacked spectra of U/LIRGs (Piqueras Lopez+, 2012)
J/ApJ/715/572 : GOALS UV and FIR properties (Howell+, 2010)
J/ApJ/723/993 : Spatial extent of (U)LIRGs in the MIR. I. (Diaz-Santos+, 2010)
J/ApJ/725/2270 : Mid-IR emission lines in AGNs (Pereira-Santaella+, 2010)
J/ApJ/658/778 : Spitzer mid-IR spectroscopy of z∼2 ULIRGs (Yan+, 2007)
J/A+A/418/465 : Mid-infrared and hard X-ray emission in AGN (Lutz+, 2004)
J/AJ/126/1607 : IRAS Revised Bright Galaxy Sample (Sanders+, 2003)
J/AJ/121/97 : K-band spectroscopy of ULIRGs (Murphy+, 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Galaxy name
17 A1 --- m_Name [*/m] Multiple system (1)
19- 20 I2 h RAh Hour of Right Ascension (J2000)
22- 23 I2 min RAm Minute of Right Ascension (J2000)
25- 29 F5.2 s RAs Second of Right Ascension (J2000)
31 A1 --- DE- Sign of the Declination (J2000)
32- 33 I2 deg DEd Degree of Declination (J2000)
35- 36 I2 arcmin DEm Arcminute of Declination (J2000)
38- 41 F4.1 arcsec DEs Arcsecond of Declination (J2000)
43- 46 F4.2 --- f6.2 ? Fraction of extended emission (FEE) of
the 6.2 micron PAH
48- 51 F4.2 --- e_f6.2 ? Uncertainty in f6.2
53- 56 F4.2 --- f6.7 Fraction of extended emission (FEE) of
the continuum at 6.7 microns
58- 61 F4.2 --- e_f6.7 Uncertainty in f6.7
63- 66 F4.2 --- f7.7 ? Fraction of extended emission (FEE) of
the 7.7 micron PAH
68- 71 F4.2 --- e_f7.7 ? Uncertainty in f7.7
73- 76 F4.2 --- f9.7 Fraction of extended emission (FEE) at
the 9.7 micron Si feature
78- 81 F4.2 --- e_f9.7 Uncertainty in f9.7
83- 86 F4.2 --- f11.3 ? Fraction of extended emission (FEE) at
the 11.3 micron PAH
88- 91 F4.2 --- e_f11.3 ? Uncertainty in f11.3
93- 96 F4.2 --- f12.8 ? Fraction of extended emission (FEE) of
the 12.8 micron [Ne II] emission line
98-101 F4.2 --- e_f12.8 ? Uncertainty in FEE12.8
103 I1 --- Type [0/4]? FEE(λ) function type (2)
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Note (1): Flag as follows:
m = Multiple systems are indicated with the same name but providing the
right ascension and declination of the individual galaxies (Flag added
by CDS).
* = Multiple nuclei, not resolved by Spitzer/IRS, are detected using higher
angular resolution HST NIR continuum imaging (Haan et al.
2011AJ....141..100H 2011AJ....141..100H).
Note (2): Type as follows:
0 = FEE(λ)∼0;
1 = constant/featureless;
2 = PAH-dominated;
3 = silicate-dominated;
4 = undefined.
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History:
From electronic version of the journal
References:
Diaz-Santos et al. Paper I. 2010ApJ...723..993D 2010ApJ...723..993D Cat. J/ApJ/723/993
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 19-Feb-2013