J/MNRAS/405/2505 Nuclear activity in ULIRGs (Nardini+, 2010)
The role of nuclear activity as the power source of ultraluminous infrared
galaxies.
Nardini E., Risaliti G., Watabe Y., Salvati M., Sani E.
<Mon. Not. R. Astron. Soc., 405, 2505-2520 (2010)>
=2010MNRAS.405.2505N 2010MNRAS.405.2505N
ADC_Keywords: Active gal. nuclei ; Galaxies, IR
Keywords: galaxies: active - galaxies: starburst - infrared: galaxies
Abstract:
We present the results of a 5-8um spectral analysis performed on
the largest sample of local ultraluminous infrared galaxies (ULIRGs)
selected so far, consisting of 164 objects up to a redshift of
∼0.35. The unprecedented sensitivity of the Infrared Spectrograph
onboard Spitzer allowed us to develop an effective diagnostic method
to quantify the active galactic nucleus (AGN) and starburst (SB)
contribution to this class of objects. The large AGN over SB
brightness ratio at 5-8um and the sharp difference between the
spectral properties of AGN and SB galaxies in this wavelength range
make it possible to detect even faint or obscured nuclear activity,
and disentangle its emission from that of star formation. By defining
a simple model we are also able to estimate the intrinsic bolometric
corrections for both the AGN and SB components, and obtain the
relative AGN/SB contribution to the total luminosity of each source.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 71 164 General properties and spectral parameters of
our local ULIRG sample
table3.dat 104 52 Properties of the 52 high-redshift sources in
the control sample
pid.dat 79 26 Spitzer programme numbers
refs.dat 69 36 References
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See also:
J/AJ/121/97 : K-band spectroscopy of ULIRGs (Murphy+, 2001)
J/A+A/409/115 : VLA imaging of IRAS 1 Jy ULIRG sample (Nagar+, 2003)
J/AJ/131/1942 : 2MASS observations of IRAS 1Jy ULIRGs (Chen+, 2006)
J/ApJ/640/167 : AGNs and ULIRGs in the CDF-South (Alonso-Herrero+, 2006)
J/A+A/467/565 : z=1-3 ULIRGs from the Spitzer SWIRE survey (Berta+, 2007)
J/ApJ/658/778 : Spitzer mid-IR spectroscopy of z∼2 ULIRGs (Yan+, 2007)
J/MNRAS/375/115 : ULIRGs galaxies in SDSS, 2dF and 6dF (Hwang+, 2007)
J/ApJ/674/172 : Oxygen abundances of LIRGs and ULIRGs (Rupke+, 2008)
J/ApJS/182/628 : Spitzer quasar and ULIRG evolution study (Veilleux+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- IRAS IRAS name (HHMMm+DDMM, B1950)
12- 16 F5.3 --- z Redshift
18- 22 F5.2 [Lsun] Lir IR luminosity (log scale)
24- 27 F4.2 [Lsun] e_Lir rms uncertainty on logLir
29- 32 F4.1 % Abol ?=- AGN contribution to the bolometric flux
34 A1 --- l_Abol1 Limit flag on DAbol (1)
35- 39 F5.2 % Abol1 1-σ confidence range in Abol (lower limit)
40 A1 --- --- [-]
41- 45 F5.2 % Abol2 ? 1-σsigma confidence range for Abol
(upper limit)
46 A1 --- l_tau Limit flag on tau
47- 50 F4.2 --- tau ?=- AGN optical depth τ
52- 56 I5 --- PID Spitzer programme number, in pid.dat file
58- 62 A5 --- Type Morphological type (LINER, H II, Sy1 or Sy2)
64 A1 --- Cl [CL-] Optical class (Compact/Loose)
66- 70 A5 --- Ref References for optical and morphological
type, in refs.dat file
71 A1 --- Note [*] * indicates an individual note (2)
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Note (1): Whenever the confidence range is provided as an upper limit, the
AGN detection is not considered as confident, with the exceptions of
00482-2720, 09463+8141, 11223-1244, 12359-0725, 16541+5301 and 20087-0308.
Note (2): Additional notes:
In the following cases the best fit has been obtained by allowing the
AGN intrinsic slope to assume the value shown in brackets, instead of
the template 1.5: 00182-7112(0.43), 00188-0856(0.78), 01572+0009(0.96),
07598+6508(0.58), 09320+6134(1.02), 11119+3257(0.47), 12127-1412(1.31),
12514+1027(1.00), 14026+4341(1.17), 19254-7245(0.52), 20037-1547(0.79),
23498+2423(0.31), 23515-2917(0.42).
Comparable minima in the parameter space suggest the presence of a
faint AGN in 02411+0354, while 14197+0812, 18531-4616 and 23365+3604
can be SB dominated.
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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- 26 A26 --- Name Object name
27 A1 --- n_Name [a-e] Group of intrinsic slope (1)
29- 32 F4.2 --- z Redshift
34- 38 F5.2 Gpc DL Luminosity distance
41- 44 F4.1 % Abol ?=- AGN contribution to bolometric flux
46 A1 --- l_Abol1 Limit flag on Abol
47- 50 F4.1 % Abol1 1-σ confidence range for Abol
(lower limit)
51 A1 --- --- [-]
52- 55 F4.1 % Abol2 ? 1-σ confidence range for Abol
(upper limit)
57 A1 --- l_tau Limit flag on tau
58- 61 F4.2 --- tau ?=- AGN optical depth τ
63- 67 F5.1 mJy Fobs Observed flux, at IRAS 60um or Spitzer-MIPS 70um
69- 72 F4.1 mJy e_Fobs rms uncertainty on Fobs
74- 78 F5.2 [Lsun] Lir IR luminosity [log scale] (2)
80- 83 F4.2 [Lsun] e_Lir rms uncertainty on logLir
85 A1 --- l_Lir2 Limit flag on logir2
86- 90 F5.2 [Lsun] Lir2 IR luminosity [log scale] (3)
92- 95 F4.2 [Lsun] e_Lir2 ? rms uncertainty on logLir
97-101 I5 --- PID Spitzer programme number, in pid.dat file
103-104 I2 --- r_Lir2 References for logLir2, in refs.dat file
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Note (1): The best fits are obtained by allowing for the values of the AGN
intrinsic slope as: a=1.36; b=1.18; c=0.98; d=1.10; e=0.70
Note (2): IR luminosity (in log of solar units) computed as
LIR = 4π(DL)2x29.3(f30um)0.93, as detailed in the text.
Note (3): tabulated IR luminosity, converted to the WMAP cosmology
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Byte-by-byte Description of file: pid.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- PID PID number
7- 79 A73 --- Title Title of the observation
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 47 A24 --- Aut Author's name
49- 69 A21 --- Com Comments
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Dec-2010