J/MNRAS/459/2948 Compact group galaxies UV and IR SFR (Lenkic+, 2016)
The ultraviolet and infrared star formation rates of compact group galaxies:
an expanded sample.
Lenkic L., Tzanavaris P., Gallagher S.C., Desjardins T.D., Walker L.M.,
Johnson K.E., Fedotov K., Charlton J., Hornschemeier A.E., Durrell P.R.,
Gronwall C.
<Mon. Not. R. Astron. Soc., 459, 2948-2963 (2016)>
=2016MNRAS.459.2948L 2016MNRAS.459.2948L (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Photometry, infrared ;
Photometry, ultraviolet
Keywords: galaxies: evolution - galaxies: photometry - galaxies: star formation
Abstract:
Compact groups of galaxies provide insight into the role of low-mass,
dense environments in galaxy evolution because the low velocity
dispersions and close proximity of galaxy members result in frequent
interactions that take place over extended time-scales. We expand the
census of star formation in compact group galaxies by Tzanavaris et
al. (2010, Cat. J/ApJS/212/9) and collaborators with Swift UVOT,
Spitzer IRAC and MIPS 24µm photometry of a sample of 183 galaxies
in 46 compact groups. After correcting luminosities for the
contribution from old stellar populations, we estimate the
dust-unobscured star formation rate (SFRUV) using the UVOT uvw2
photometry. Similarly, we use the MIPS 24 µm photometry to estimate
the component of the SFR that is obscured by dust (SFRIR). We find
that galaxies which are MIR-active (MIR-'red'), also have bluer UV
colours, higher specific SFRs, and tend to lie in HI-rich groups,
while galaxies that are MIR-inactive (MIR-'blue') have redder UV
colours, lower specific SFRs, and tend to lie in HI-poor groups. We
find the SFRs to be continuously distributed with a peak at about
1M☉/yr, indicating this might be the most common value in
compact groups. In contrast, the specific SFR distribution is bimodal,
and there is a clear distinction between star-forming and quiescent
galaxies. Overall, our results suggest that the specific SFR is the
best tracer of gas depletion and galaxy evolution in compact groups.
Description:
The sample of CGs studied here is the same sample studied by Walker et
al. (2012AJ....143...69W 2012AJ....143...69W) of 49 CGs: 33 Hickson Compact Groups and 16
Redshift Survey Compact Groups (RSCGs).
The RSCG catalogue of 89 CGs was constructed by Barton et al.
(1996AJ....112..871B 1996AJ....112..871B).
The data used in this study originated from 'fill-in' observations
with UVOT's three UV filters (uvw2, uvm2, uvw1) as well as the bluest
optical filter (u). All UV data (PI: Tzanavaris) were downloaded from
the Swift archive.
The Spitzer Infrared Array Camera images for our sample of CGs are
archival data presented by Walker et al. (2012AJ....143...69W 2012AJ....143...69W)
Spitzer MIPS (24um) data were obtained from the Spitzer Heritage
Archive.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
groups.dat 32 43 Studied groups
table3.dat 80 217 Observation log for Swift UVOT HCG and RSCG data
table5.dat 126 174 UVOT, MIPS 24um and IRAC 3.6 and 4.5um fluxes
for HCG and RSCG galaxies
table6.dat 77 169 UV and IR properties of HCG and RSCG galaxies
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See also:
J/ApJS/212/9 : X-ray sources in Hickson Compact Groups (Tzanavaris+, 2014)
Byte-by-byte Description of file: groups.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Group Group name
10- 11 I2 h RAh Simbad right ascension (J2000)
13- 14 I2 min RAm Simbad right ascension (J2000)
16- 20 F5.2 s RAs Simbad right ascension (J2000)
22 A1 --- DE- Simbad declination sign (J2000)
23- 24 I2 deg DEd Simbad declination (J2000)
26- 27 I2 arcmin DEm Simbad declination (J2000)
29- 32 F4.1 arcsec DEs ? Simbad declination (J2000)
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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- 7 A7 --- Group Group ID
9- 19 I11 --- ObsID Observation ID
21- 52 A32 --- Obs.Date Dates of Observations
53- 57 I5 s ExpTUVW2 ? Total Exposure Times for Swift UVOT filter UVW2
61- 65 I5 s ExpTUVM2 ? Total Exposure Times for Swift UVOT filter UVM2
69- 73 I5 s ExpTUVW1 ? Total Exposure Times for Swift UVOT filter UVW1
76- 80 I5 s ExpTU ? Total Exposure Times for Swift UVOT filter U
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- CGG Compact Group Galaxy name
11- 16 F6.1 10-19W/m2 FUVW2 ?=- UVOT UVW2 flux density
18- 21 F4.1 10-19W/m2 e_FUVW2 ? rms uncertainty on FUVW2
23 A1 --- l_FUVW2c Limit flag on FUVW2c
24- 30 F7.3 10-19W/m2 FUVW2c ?=- UVOT UVW2 flux density corrected for
emission from old stellar populations
32- 37 F6.1 10-19W/m2 FUVM2 ?=- UVOT UVM2 flux density
39- 42 F4.1 10-19W/m2 e_FUVM2 ? rms uncertainty on FUVM2
44- 49 F6.1 10-19W/m2 FUVW1 ?=- UVOT UVW1 flux density
51- 54 F4.1 10-19W/m2 e_FUVW1 ? rms uncertainty on FUVW1
57- 62 F6.1 10-19W/m2 FU ?=- UVOT U flux density
64- 67 F4.1 10-19W/m2 e_FU ? rms uncertainty on FU
68- 70 A3 --- n_FU [(b)] Note on FU (1)
73- 76 F4.1 mag UVM2mag ?=- UVM2 AB magnitude
79- 83 F5.1 mJy F3.6 ?=- IRAC 3.6um flux density
85- 88 F4.1 mJy e_F3.6 ?=- rms uncertainty on F3.6
90- 94 F5.1 mJy F4.5 ?=- IRAC 4.5um flux density
96- 99 F4.1 mJy e_F4.5 ?=- rms uncertainty on F4.5
101-106 F6.1 mJy F24 ?=- MIPS 24um flux density
108-112 F5.1 mJy e_F24 ? rms uncertainty on F24
114 A1 --- l_F24c Limit flag on F24c
115-120 F6.1 mJy F24c ?=- 24 micron flux density corrected for
emission from old stellar populations
122-126 F5.1 mJy e_F24c ? rms uncertainty on F24c
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Note (1): (b) : We checked our UV data for coincidence loss effects using
the method of Poole et al. (2008MNRAS.383..627P 2008MNRAS.383..627P), by measuring the
non-background subtracted count rates in circular apertures within a 5 arcsec
radius centred on the surface brightness peak. Consistent with the results of
Tzanavaris et al. (2010ApJ...716..556T 2010ApJ...716..556T), we found that the U filter images
were most significantly affected by coincidence loss;
32 of 120 galaxies with U data suffered from coincidence loss, whereas
only 6, 2, and 5 galaxies suffered from coincidence loss effects in the
UVW1, UVM2, and UVW2 filters, respectively.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1 A1 --- Case [A/Q] Case (1)
3- 12 A10 --- CGG Compact Group Galaxy name
14- 15 A2 --- MType Galaxy Morphology (2)
17- 21 F5.2 [10-7W/Hz] logLUVW2 ?=- UVOT UVW2 luminosity
23- 27 F5.2 [10-7W/Hz] logLUVM2 ?=- UVOT UVM2 luminosity
29- 33 F5.2 [10-7W/Hz] logLUVW1 ?=- UVOT UVM1 luminosity
35- 39 F5.2 [10-7W/Hz] logLU ? UVOT U luminosity
41- 45 F5.2 [10-7W/Hz] logL24 ? MIPS 24um luminosity
47- 51 F5.2 [Msun] logM* ?=- Stellar mass
53- 57 F5.2 --- alphaIRAC ? alphaIRAC parameter, obtained from
Dejardins et al. (2015,
AAS Meeting, 225, 321.02)
59- 63 F5.3 --- SFRuvw2 ?=- UV component of the star formation rate
65- 70 F6.3 --- SFR24um ?=- IR component of the total star formation
72- 77 F6.3 10-11 SSFR ?=- Specific star formation rate (3)
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Note (1): Case as follows:
A = Actively Star Forming (alphaIRAC≤0)
Q = Quiescent (alphaIRAC>0)
Note (2): Morphology of each galaxy, obtained from
Tyler Desjardins, priv. comm.,
Note (3): Specific star formation rate, which is the total star formation rate,
normalized by stellar mass.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 28-Jul-2017