J/A+A/617/A130 Luminous infrared galaxies AKARI 2.5-5um data (Inami+, 2018)
The AKARI 2.5-5 micron spectra of luminous infrared galaxies in the
local Universe.
Inami H., Armus L., Matsuhara H., Charmandaris V., Diaz-Santos T.,
Surace J., Stierwalt S., Ohyama Y., Howell J., Marshall J., Evans A.S.,
Linden S.T., Mazzarella J.
<Astron. Astrophys. 617, A130 (2018)>
=2018A&A...617A.130I 2018A&A...617A.130I (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, IR ; Equivalent widths ; Spectra, infrared
Keywords: galaxies: starburst - galaxies: active - infrared: galaxies
Abstract:
We present AKARI 2.5-5um spectra of 145 local luminous infrared
galaxies (LIRG; LIR≥1011L☉) in the Great Observatories All-sky
LIRG Survey (GOALS). In all of the spectra, we measure the line fluxes
and equivalent widths (EQWs) of the polycyclic aromatic hydrocarbon
(PAH) at 3.3um and the hydrogen recombination line Brα at
4.05um, with apertures matched to the slit sizes of the Spitzer
low-resolution spectrograph and with an aperture covering ∼95% of
the total flux in the AKARI two-dimensional (2D) spectra. The star
formation rates (SFRs) derived from the Brα emission measured in
the latter aperture agree well with SFRs estimated from LIR, when the
dust extinction correction is adopted based on the 9.7um silicate
absorption feature. Together with the Spitzer Infrared Spectrograph
(IRS) 5.2-38um spectra, we are able to compare the emission of the
PAH features detected at 3.3um and 6.2um. These are the two most
commonly used near/mid-infrared indicators of starburst or active
galactic nucleus (AGN) dominated galaxies. We find that the 3.3um and
6.2um PAH EQWs do not follow a linear correlation and at least a third
of the galaxies classified as AGN-dominated sources using the 3.3um
feature are classified as starbursts based on the 6.2um feature. These
galaxies have a bluer continuum slope than galaxies that are indicated
to be starburst-dominated by both PAH features. The bluer continuum
emission suggests that their continuum is dominated by stellar
emission rather than hot dust. We also find that the median
Spitzer/IRS spectra of these sources are remarkably similar to the
pure starburst-dominated sources indicated by high PAH EQWs in both
3.3um and 6.2um. Based on these results, we propose a revised
starburst/AGN diagnostic diagram using 2-5um data: the 3.3um PAH EQW
and the continuum color, Fν(4.3um)/Fν(2.8um). We use the AKARI
and Spitzer spectra to examine the performance of our new
starburst/AGN diagnostics and to estimate 3.3um PAH fluxes using the
James Webb Space Telescope (JWST) photometric bands in the redshift
range 0<z<5. Of the known PAH features and mid-infrared high
ionization emission lines used as starburst/AGN indicators, only the
3.3um PAH feature is observable with JWST at z>3.5, because the rest
of the features at longer wavelengths fall outside the JWST wavelength
coverage.
Description:
We present the table of line flux and equivalent width (EQW) of
3.3um polycyclic aromatic hydrocarbon (PAH) and Brackett-alpha,
and the continuum color of Fnu(4.3um)/Fnu(2.8um) measured in
145 AKARI spectra using the 4.4-arcsecond radius aperture (Table 1).
The EQW of 6.2-micron PAH from Stierwalt et al. (2013, Cat.
J/ApJS/206/1) is presented together. We also publish the data of the
median SEDs of starburst- and AGN-dominated LIRGs as shown in
Figure 9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 111 145 Line flux and equivalent widths of 3.3um PAH and
Bra, the continuum color, and EW(6.2um PAH)
sed-agn.dat 25 607 Median SED of AGN-dominated LIRGs
sed-sb.dat 25 603 Median SED of starburst-dominated LIRGs
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See also:
J/ApJS/206/1 : Mid-IR properties of GOALS nearby LIRGs (Stierwalt+, 2013)
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 Object name
17 A1 --- Tag [*] Note (1)
19- 28 F10.6 deg RAdeg Right Ascension (J2000)
30- 39 F10.6 deg DEdeg Declination (J2000)
41 A1 --- l_F3.3 Upper limit flag on 3.3 micron PAH flux
42- 46 F5.2 10-16W/m2 F3.3 Flux of 3.3 micron PAH
48- 51 F4.2 10-16W/m2 e_F3.3 ? Uncertainty of 3.3 micron PAH flux
53 A1 --- l_EW3.3 Limit flag on 3.3 micron PAH EQW
54- 58 F5.3 um EW3.3 Equivalent width of 3.3 micron PAH
60- 64 F5.3 um e_EW3.3 ? Uncertainty of 3.3 micron PAH EQW
66 A1 --- l_FBra Upper limit flag on Bra flux
67- 70 F4.2 10-16W/m2 FBra Flux of Bra
72- 75 F4.2 10-16W/m2 e_FBra ? Uncertainty of Bra flux
77 A1 --- l_EWBra Upper limit flag on Bra EQW
78- 82 F5.3 um EWBra Equivalent width of Bra
84- 88 F5.3 um e_EWBra ? Uncertainty of Bra EQW
90- 93 F4.2 --- Color Continuum color of Fnu(4.3um)/Fnu(2.8um)
95- 98 F4.2 --- e_Color Uncertainty of Continuum color
100 A1 --- l_EW6.2 Upper limit flag on 6.2 micron PAH EQW
101-105 F5.3 um EW6.2 ? Equivalent width of 6.2 micron PAH
107-111 F5.3 um e_EW6.2 ? Uncertainty of 6.2 micron PAH EQW
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Note (1): * indicates of mismatched pointings between AKARI and Spitzer
observations or too extended morphologies to combine the AKARI and Spitzer
spectra.
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Byte-by-byte Description of file: sed-agn.dat sed-sb.dat
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Bytes Format Units Label Explanations
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1- 7 F7.4 um Lambda Rest-frame wavelength
10- 16 F7.4 mJy B_Flux Upper value of the normalized flux density
19- 25 F7.4 mJy b_Flux Lower value of the normalized flux density
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Acknowledgements:
Hanae Inami, hanae.inami(at)univ-lyon1.fr
(End) Patricia Vannier [CDS] 08-Jul-2018