J/ApJ/934/27 Spitzer/IRS spectral stacking analysis of GOALS gal. (Stone+, 2022)
Measuring star formation and black hole accretion rates in tandem using
mid-infrared spectra of local infrared luminous galaxies.
Stone M., Pope A., McKinney J., Armus L., Diaz-Santos T., Inami H.,
Kirkpatrick A., Stierwalt S.
<Astrophys. J., 934, 27 (2022)>
=2022ApJ...934...27S 2022ApJ...934...27S
ADC_Keywords: Galaxies, IR; Spectra, infrared
Keywords: Luminous infrared galaxies ; Ultraluminous infrared galaxies ;
Supermassive black holes ; Star formation ; Galaxy evolution
Abstract:
We present the results of a stacking analysis performed on
Spitzer/Infrared Spectrograph high-resolution mid-infrared (mid-IR)
spectra of luminous infrared galaxies (LIRGs) in the Great
Observatories All-Sky LIRG Survey. By binning in relation to mid-IR
active galactic nucleus (AGN) fraction and stacking spectra, we detect
bright emission lines [NeII] and [NeIII], which trace star formation,
and fainter emission lines [NeV] and [OIV], which trace AGN activity,
throughout the sample. We find that the [NeII] luminosity is fairly
constant across all AGN fraction bins, while the [OIV] and [NeV]
luminosities increase by over an order of magnitude. Our measured
average line ratios, [NeV]/[NeII] and [OIV]/[NeII], at low AGN
fraction are similar to HII galaxies, while the line ratios at high
AGN fraction are similar to LINERs and Seyferts. We decompose the
[OIV] luminosity into star formation and AGN components by fitting the
[OIV] luminosity as a function of the [NeII] luminosity and the mid-IR
AGN fraction. The [OIV] luminosity in LIRGs is dominated by star
formation for mid-IR AGN fractions ≲0.3. With the corrected [OIV]
luminosity, we calculate black hole accretion rates (BHARs) ranging
from 10-5M☉/yr at low AGN fractions to 0.2M☉/yr at the
highest AGN fractions. We find that using the [OIV] luminosity,
without correcting for star formation, can lead to overestimation of
the BHAR by up to a factor of 30 in starburst-dominated LIRGs.
Finally, we show that the BHAR/star formation rate ratio increases by
more than three orders of magnitude as a function of mid-IR AGN
fraction in LIRGs.
Description:
Our sample consists of GOALS galaxies with high-resolution (R=600)
Spitzer/IRS data in both the short-high (SH) and long-high (LH)
channels (Inami+ 2013, J/ApJ/777/156). We retrieved the 1D reduced
spectra from the Infrared Science Archive (GOALS Team 2020,
doi:10.26131/IRSA183).
We perform a spectral stacking analysis as a function of mid-IR AGN
fraction using 203 Spitzer/IRS spectra of the GOALS sample in order to
explore the coevolution of the mid-IR atomic emission lines 12.8um
[NeII], 14.3um [NeV], 15.5um [NeIII], and 25.9um [OIV].
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 68 6 Properties of our six mid-IR AGN fraction bins
fig2.dat 116 1632 Spitzer/IRS spectra for our 6 bins of AGN fraction
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See also:
J/AJ/126/1607 : IRAS Revised Bright Galaxy Sample (Sanders+, 2003)
J/ApJ/656/770 : Mid-IR spectrum of star-forming galaxies (Smith+, 2007)
J/ApJS/182/628 : Spitzer quasar and ULIRG evolution study (Veilleux+, 2009)
J/ApJ/723/993 : Spatial extent of LIRGs in the MIR. I. (Diaz-Santos+, 2010)
J/ApJ/725/2270 : Mid-IR emission lines in AGNs (Pereira-Santaella+, 2010)
J/ApJ/709/1257 : Spitzer-IRS sp. of Seyfert galaxies. II. (Tommasin+, 2010)
J/ApJ/741/32 : Spatial extent of LIRGs in the MIR. II. (Diaz-Santos+, 2011)
J/ApJ/777/156 : Spitzer/IRS sp. of GOALS luminous IR galaxies (Inami+, 2013)
J/ApJS/206/1 : Mid-IR properties of GOALS nearby LIRGs (Stierwalt+, 2013)
J/ApJ/790/124 : Dust and gas physics of the GOALS sample (Stierwalt+, 2014)
J/A+A/574/A4 : Radio image of Luminous IR Galaxies (Vardoulaki+, 2015)
J/ApJ/846/32 : Herschel FIR spectra of GOALS galaxies (Diaz-Santos+, 2017)
J/MNRAS/487/1823 : MIR spectra of AGNs heating molecular gas (Lambrides+, 2019)
http://irsa.ipac.caltech.edu/data/GOALS/ : GOALS IRSA data access
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Bin Bin number
7- 8 I2 --- Ngal [20/41] Number of galaxies
10- 13 F4.2 --- fmir [0.1/0.96] Median mid-IR AGN fraction (1)
15- 18 F4.2 --- b_fmir [0/0.81] fmir lower limit (1)
20- 23 F4.2 --- B_fmir [0.15/1] fmir upper limit (1)
25- 29 F5.2 --- MedLIR [11.25/12] Median IR luminosity
31- 34 F4.1 --- b_MedLIR [11.1/11.4] MedLIR lower limit
36- 39 F4.1 --- B_MedLIR [11.5/12] MedLIR upper limit
41- 45 F5.1 Mpc Dist [86/148.5] Median luminosity distance
47- 50 F4.1 Mpc b_Dist [69.9/87.3] Dist lower limit
52- 56 F5.1 Mpc B_Dist [112.5/197.3] Dist upper limit
58- 60 F3.1 --- SH-LH [1.2/1.6] Median SH-LH scale factor
62- 64 F3.1 --- b_SH-LH [1.1/1.3] SH-LH lower limit
66- 68 F3.1 --- B_SH-LH [1.3/2] SH-LH upper limit
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Note (1): measured from the 6.2um PAH EQW (Diaz-Santos+ 2017, J/ApJ/846/32).
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Byte-by-byte Description of file: fig2.dat
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Bytes Format Units Label Explanations
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1- 8 F8.5 um lambda [9.89/36.5] Wavelength
10- 17 F8.6 Jy Flux1 [0.08/6.2] Bin 1 flux density
19- 26 F8.6 Jy e_Flux1 [0.002/0.61] Uncertainty in Flux1
28- 35 F8.6 Jy Flux2 [0.07/5.1]? Bin 2 flux density
37- 44 F8.6 Jy e_Flux2 [0.001/0.4]? Uncertainty in Flux2
46- 53 F8.6 Jy Flux3 [0.066/6.3] Bin 3 flux density
55- 62 F8.6 Jy e_Flux3 [0.0029/0.4] Uncertainty in Flux3
64- 71 F8.6 Jy Flux4 [0.06/5.1] Bin 4 flux density
73- 80 F8.6 Jy e_Flux4 [0.002/0.4] Uncertainty in Flux4
82- 89 F8.6 Jy Flux5 [0.086/5.6]? Bin 5 flux density
91- 98 F8.6 Jy e_Flux5 [0.004/0.5]? Uncertainty in Flux5
100- 107 F8.6 Jy Flux6 [0.16/7.6]? Bin 6 flux density
109- 116 F8.6 Jy e_Flux6 [0.006/1.5]? Uncertainty in Flux6
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Jun-2024