J/ApJ/586/794 Multiwavelength luminosities of galaxies (Bell, 2003)
Estimating star formation rates from infrared and radio luminosities:
the origin of the radio-infrared correlation.
Bell E.F.
<Astrophys. J. 586, 794 (2003)>
=2003ApJ...586..794B 2003ApJ...586..794B
ADC_Keywords: Galaxies, photometry ; Magnitudes ; Photometry, infrared ;
Photometry, ultraviolet ; Radio lines
Keywords: cosmic rays - dust, extinction - galaxies: general -
infrared: galaxies - radio continuum: galaxies -
ultraviolet: galaxies
Abstract:
I have assembled a diverse sample of galaxies from the literature with
far-ultraviolet (FUV), optical, infrared (IR), and radio luminosities
to explore the calibration of radio-derived and IR-derived star
formation (SF) rates and the origin of the radio-IR correlation. By
comparing the 8-1000µm IR, which samples dust-reprocessed
starlight, with direct stellar FUV emission, I show that the IR traces
most of the SF in luminous ∼L* galaxies but traces only a small
fraction of the SF in faint ∼0.01L* galaxies. If radio emission were a
perfect SF rate indicator, this effect would cause easily detectable
curvature in the radio-IR correlation. Yet, the radio-IR correlation
is nearly linear. This implies that the radio flux from low-luminosity
galaxies is substantially suppressed, compared to brighter galaxies.
This is naturally interpreted in terms of a decreasing efficiency of
nonthermal radio emission in faint galaxies. Thus, the linearity of
the radio-IR correlation is a conspiracy: both indicators
underestimate the SF rate at low luminosities. SF rate calibrations
that take into account this effect are presented, along with estimates
of the random and systematic error associated with their use.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 128 249 Galaxy Luminosities
refs.dat 196 59 References
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Galaxy Galaxy name
17- 21 F5.2 [10W/nm] logFUV ? Log of the Far UltraViolet
luminosity (1)
23- 26 F4.2 [10W/nm] e_logFUV ? Error in FUV (1)
28- 32 F5.2 [W] logLIRtot ? Log of the total Infrared
luminosity (2)
34- 38 F5.2 [W] logLFIR ? The Far Infrared IRAS luminosity
computed following Helou et al.
(1988ApJS...68..151H 1988ApJS...68..151H)
40- 43 F4.2 --- F100/60 ? The IRAS 100 to 60 micron ratio
45- 49 F5.2 [W/Hz] logL1.4GHz ? Log of the 1.4 GHz luminosity
51- 54 F4.2 [W/Hz] e_logL1.4GHz ? Error in 1.4GHz
56- 60 F5.3 --- fTher ? Thermal radio fraction (3)
62- 66 F5.3 --- e_fTher ? Error in fTher
68- 73 F6.2 mag VMAG ? Absolute V band magnitude (4)
75- 78 F4.2 mag e_VMAG ? Error in VMAG
80- 83 F4.2 mag AV Extinction in the V band magnitude
85- 89 F5.1 Mpc Dist Distance
91- 95 F5.2 [W] logLHa ? Log of the Hα luminosity
97-100 F4.2 mag AHa ? Hα extinction from the Balmer
decrement (5)
102-108 A7 --- MType Morphology type
110-123 A14 --- Refs References, in refs.dat file (6)
126-128 A3 --- Notes Notes (7)
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Note (1): In units of W/Å and at wavelength ∼1550Å.
Note (2): From 8-1000 microns. The IR data are taken from (in order of
preference) Rice et al. (1988ApJS...68...91R 1988ApJS...68...91R), Soifer et al.
(1989AJ.....98..766S 1989AJ.....98..766S), and Moshir et al. (1990, Cat. II/156).
Note (3): Thermal radio fractions are taken from (in order of preference)
Bell & Kennicutt (2001ApJ...548..681B 2001ApJ...548..681B) and Niklas et al.
(1997A&A...322...19N 1997A&A...322...19N).
Note that Bell & Kennicutt (2001ApJ...548..681B 2001ApJ...548..681B) obtains thermal
fractions from a variety of sources, with the majority from
Niklas et al. (1997A&A...322...19N 1997A&A...322...19N).
Note (4): The optical data are taken from the RC3 de Vaucouleurs et al.
(1991, Cat. VII/155) or the ESO-LV catalog
Lauberts & Valentijn (1989, Cat. VII/34) unless otherwise stated.
Note (5): Balmer decrements are taken from Bell & Kennicutt
(2001ApJ...548..681B 2001ApJ...548..681B) for normal galaxies (and are averages of
individual H II region Balmer decrements) and from Calzetti et al.
(1994ApJ...429..582C 1994ApJ...429..582C) and Wu et al. (1998A&AS..127..521W 1998A&AS..127..521W) for
starbursting galaxies and ULIRGs respectively.
Note (6): References:
UV data: 1a to 1f
Radio data: 2a to 2h
Optical V-band data: 3a to 3m
Distances: 4a to 4z
Hα data: 5a to 5g
Note (7): Notes as follows:
a = Bell & Kennicutt (2001ApJ...548..681B 2001ApJ...548..681B) presents all of the data
except for the radio luminosity.
b = This galaxy has a major axis optical diameter ≥1.5',
so its UV data is ignored to minimize aperture bias.
c = Bell & Kennicutt (2001ApJ...548..681B 2001ApJ...548..681B) presents all of the data
for this galaxy except for the UV flux and radio luminosity:
the UV flux is taken from Rifatto, Longo & Capaccioli
(1995A&AS..114..527R 1995A&AS..114..527R).
d = The radio data are also taken from Bell & Kennicutt
(2001ApJ...548..681B 2001ApJ...548..681B) for NGC 4038/9 and NGC 25
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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 A2 --- Ref Reference code
4- 22 A19 --- BibCode BibCode
24- 56 A33 --- Aut Author's name
59-198 A140 --- Com Comments
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 22-May-2003