J/ApJ/453/616 JHKL photometry of 12 micron galaxy sample (Spinoglio+ 1995)
Multiwavelength energy distributions and bolometric luminosities of the 12
micron galaxy sample
Spinoglio L., Malkan M.A., Rush B., Carrasco L., Recillas-Cruz E.
<Astrophys. J. 453, 616 (1995)>
=1995ApJ...453..616S 1995ApJ...453..616S
ADC_Keywords: Galaxies, photometry ; Photometry, infrared
Keywords: galaxies: active - galaxies: nuclei - galaxies: photometry -
galaxies: Seyfert - galaxies: starburst - infrared: galaxies
Abstract:
Aperture photometry from our own observations and the literature is
presented for the 12 um galaxies in the near-infrared J, H, and K
bands and, in some cases, in the L band. These data are corrected to
"total" near-infrared magnitudes (with a typical uncertainty of
0.3mag) for a direct comparison with our IRAS fluxes which apply to
the entire galaxy. The corrected data are used to derive integrated
total near-infrared and far-infrared luminosities. We then combine
these with blue photometry and an estimate of the flux contribution
from cold dust at wavelengths longward of 100um to derive the first
bolometric luminosities for a large sample of galaxies. The presence
of nonstellar radiation at 2-3um correlates very well with nonstellar
IRAS colors. This enables us to identify a universal Seyfert nuclear
continuum from near- to far-infrared wavelengths. Thus, there is a
sequence of infrared colors which runs from a pure "normal galaxy" to
a pure Seyfert/quasar nucleus. Seyfert 2 galaxies fall close to this
same sequence, although only a few extreme narrow-line Seyfert
galaxies have quasar-like colors, and these show strong evidence of
harboring an obscured broad-line region. A corollary is that the host
galaxies of Seyfert nuclei have normal near- to far-infrared spectra
on average. Starburst galaxies lie significantly off the sequence,
having a relative excess of 60um emission probably as a result of
stochastically heated dust grains. We use these correlations to
identify several combinations of infrared colors which discriminate
between Seyfert 1 and 2 galaxies, LINERs, and ultraluminous
starbursts. In the infrared, Seyfert 2 galaxies are much more like
Seyfert 1s than they are like starbursts, presumably because both
kinds of Seyferts are heated by a single central source, rather than a
distributed region of star formation. Moreover, combining the
[25-2.2um] color with the [60-12um] color, it appears that Seyfert 1
galaxies are segregated from Seyfert 2 galaxies and starburst galaxies
in a well-defined region characterized by the hottest colors,
corresponding to the flattest spectral slopes. Virtually no Seyfert 2
galaxy is present in such a region. To reconcile this with the
"unified scheme" for Seyfert 1 and 2 galaxies would therefore require
that the higher frequency radiation from the nuclei of Seyfert 2
galaxies to be absorbed by intervening dust and re-emitted at lower
frequencies. We find that bolometric luminosity is most closely
proportional to 12um luminosity. The 60 and 25um luminosities rise
faster than linearly with bolometric luminosity, while the optical
flux rises less than linearly with bolometric luminosity. This result
is a confirmation of the observation that more luminous disk galaxies
have relatively more dust-enshrouded stars. Increases in the dust
content shifts luminosity from the optical to 25-60um, while leaving a
"pivot point" in the mid-IR essentially unchanged. Thus, 12um
selection is the closest available approximation to selection by a
limiting bolometric flux, which is approximately 14 times nu.L_nu at
12um for non-Seyfert galaxies. It follows that future deep surveys in
the mid-infrared, at wavelengths of 8-12um, will simultaneously
provide complete samples to different bolometric flux levels of normal
and active galaxies, which will not suffer the strong selection
effects present both in the optical-UV and far-infrared.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1 75 408 Near-IR photometry of the 12 micron galaxy
sample
table2 79 19 Near-IR photometry of galaxies excluded from
the 12 micron sample
table3.dat 77 514 Derived NIR parameters for the 12 micron
galaxy sample
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See also:
VII/157 : The extended 12um galaxy sample (Rush+ 1993)
Byte-by-byte Description of file: table1 table2
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Name of galaxy
14- 15 I2 h RAh *? Right ascension (B1950.0), from IRAS FSC
17- 18 I2 min RAm *? Right ascension (B1950.0), from IRAS FSC
20- 23 F4.1 s RAs *? Right ascension (B1950.0), from IRAS FSC
25 A1 --- DE- Declination sign
26- 27 I2 deg DEd *? Declination (B1950.0), from IRAS FSC
29- 30 I2 arcmin DEm *? Declination (B1950.0), from IRAS FSC
32- 33 I2 arcsec DEs *? Declination (B1950.0), from IRAS FSC
35- 40 F6.1 mJy FnuJ ? J-band flux density
41 A1 --- u_FnuJ FnuJ uncertainty flag
42- 47 F6.1 mJy FnuH H-band flux density
48 A1 --- u_FnuH FnuH uncertainty flag
49- 54 F6.1 mJy FnuK ? K-band flux density
55 A1 --- u_FnuK FnuK uncertainty flag
56- 61 F6.1 mJy FnuL ? L-band flux density
62 A1 --- u_FnuL FnuL uncertainty flag
63- 65 I3 arcsec Diam Diameter of observing aperture
67- 73 A7 --- Date Site (ESO or SPM [San Pedro Martir]) and date
75 I1 --- Type [0-4] Object Type: 1, 2 = Seyfert1,2;
3 = IR-luminous; 4 = Liner; 0 = normal
77- 79 A3 --- Flag *Flags explaining why object was observed
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Note on RAh, RAm, RAs, DEd, DEm, DEs: Positions from IRAS FSC II/156.
Blank when the galaxy is not in IRAS FSC.
Note on Flag:
a: originally in the 12-Micron Sample, based on its flux in the FSC-2,
but later excluded because the ADDSCAN flux is below the sample
limit (see Appendix A of Rush, Malkan, and Spinoglio 1993 VII/157,
hereafter RMS93)
b: in Spinoglio & Malkan (1989ApJ...342...83S 1989ApJ...342...83S)
c: unidentified object excluded from the 12-Micron Sample in RMS93 VII/157
(see Table 12 of RMS93).
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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- 12 A12 --- Name Name of galaxy
14- 20 F7.5 --- z Redshift (corrected as described in RMS93)
22- 25 F4.2 [mJy] log(FJmag) []? Computed total flux in the J band
27- 30 F4.2 [mJy] log(FHmag) []? Computed total flux in the H band
32- 35 F4.2 [mJy] log(FKmag) []? Computed total flux in the K band
37- 40 F4.2 mag J-H []? J-H color, smallest available aperture
42- 45 F4.2 mag H-K []? H-K color, smallest available aperture
47- 50 F4.2 mag K-L []? K-L color, smallest available aperture
52- 53 I2 arcsec Apert []? Aperture for colors (for [H-K] if
different for each)
55- 59 F5.2 [10-7W] log(LNIR) []? Luminosity integrated over 1.2-3.4um
61- 65 F5.2 [10-7W] log(LFIR) Luminosity integrated over IRAS wavebands
67- 71 F5.2 [10-7W] log(LTOT) []? Bolometric luminosity
73 I1 --- Type [0-4] Object Type: 1, 2 = Seyfert1,2;
3 = IR-luminous; 4 = Liner; 0 = normal
75- 77 A3 --- Flag *Flags pertaining to apertures and colors
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Note on Flag:
a A Seyfert galaxy for which the authors only have whole-galaxy
(extrapolated) colors and thus no aperture is given
b An object for which no aperture was given with the reference,
but where the authors can assume that these are whole-galaxy
fluxes because it is very point-like
J The [J-H] is from a larger aperture than the [H-K] color (10 objects)
L The [K-L] is from a larger aperture than the [H-K] color (7 objects)
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Origin: AAS CD-ROM series, Volume 5, 1995 Lee Brotzman [ADS] 04-Nov-95
(End) [CDS] 29-Jan-1996