J/ApJ/836/7 SG1120-1202 members HST imaging & 24um fluxes (Monroe+, 2017)
SG1120-1202: mass-quenching as tracked by UV emission in the group
environment at z=0.37.
Monroe J.T., Tran K.-V.H., Gonzalez A.H.
<Astrophys. J., 836, 7-7 (2017)>
=2017ApJ...836....7M 2017ApJ...836....7M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Photometry, HST ; Ultraviolet ;
Photometry, infrared ; Redshifts
Keywords: galaxies: clusters: individual: "SG1120-1202";
galaxies: evolution; galaxies: photometry; galaxies: starburst;
galaxies: structure
Abstract:
We use the Hubble Space Telescope to obtain WFC3/F390W imaging of the
supergroup SG1120-1202 at z=0.37, mapping the UV emission of 138
spectroscopically confirmed members. We measure total (F390W-F814W)
colors and visually classify the UV morphology of individual galaxies
as "clumpy" or "smooth." Approximately 30% of the members have pockets
of UV emission (clumpy) and we identify for the first time in the
group environment galaxies with UV morphologies similar to the
"jellyfish" galaxies observed in massive clusters. We stack the clumpy
UV members and measure a shallow internal color gradient, which
indicates that unobscured star formation is occurring throughout these
galaxies. We also stack the four galaxy groups and measure a strong
trend of decreasing UV emission with decreasing projected group
distance (Rproj). We find that the strong correlation between
decreasing UV emission and increasing stellar mass can fully account
for the observed trend in (F390W-F814W)-Rproj, i.e., mass-quenching
is the dominant mechanism for extinguishing UV emission in group
galaxies. Our extensive multi-wavelength analysis of SG1120-1202
indicates that stellar mass is the primary predictor of UV emission,
but that the increasing fraction of massive (red/smooth) galaxies at
Rproj≲2R200 and existence of jellyfish candidates is due to the
group environment.
Description:
We employ HST imaging of an ∼8'x12' mosaic across three filters: F390W
(WFC3/UVIS), F606W (ACS/WFC), and F814W (ACS/WFC) for a total of 44
pointings (combined primary and parallels) during cycles 14 (GO 10499)
and 19 (GO 12470).
We use the Spitzer MIPS 24um fluxes from Saintonge+
(2008ApJ...685L.113S 2008ApJ...685L.113S) and Tran+ (2009ApJ...705..809T 2009ApJ...705..809T). The 24um
observations were retrieved from the Spitzer archive.
For details on spectroscopy from multi-band ground-based observations
using Magellan (in 2006), MMT, and VLT/VIMOS (in 2003), we refer the
reader to Tran+ (2009ApJ...705..809T 2009ApJ...705..809T).
Objects:
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RA (ICRS) DE Designation(s)
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11 20.0 -12 02 SG1120-1202 = [GTC2005] SG J1120-1202
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 83 137 Observed properties of supergroup members
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See also:
J/ApJ/500/714 : Color-magnitude relation in CL 1358+62 (Van Dokkum+ 1998)
J/ApJ/496/39 : Properties of poor groups of galaxies. I. (Zabludoff+ 1998)
J/ApJS/137/117 : Las Campanas Distant Cluster Survey (LCDCS) (Gonzales+, 2001)
J/ApJ/549/172 : X-ray-detected, poor groups galaxy populations (Tran+, 2001)
J/ApJS/214/24 : 3D-HST+CANDELS catalog (Skelton+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Identifier (JHHMMSS.s+DDMMSS.s)
20- 25 F6.4 --- z [0.3/0.4] Spectroscopic redshift
27- 29 I3 kpc Rproj [0/932] Projected radius
31- 34 F4.2 mJy F24 [0.03/6.1]? Spitzer/MIPS 24um flux density (1)
36- 39 F4.2 kpc Rhalf [0.4/6.6] Half-light radius in F814W image (2)
41- 45 F5.2 mag F814Wmag [18.5/23.4] HST/ACS F814W band magnitude (3)
47- 51 F5.3 mag e_F814Wmag [0.001/0.03] Uncertainty in F814Wmag
53- 57 F5.2 mag F390Wmag [20.7/25.5] HST/WFC3 F390W band magnitude (3)
59- 63 F5.3 mag e_F390Wmag [0.002/0.08] Uncertainty in F390Wmag
65- 68 F4.1 [Msun] logMass [8/12] Log stellar mass (4)
70- 81 A12 --- Clumpy Clumpy ("Clumpy" (39 occurrences), "Smooth" or
"Unclassified" (8 occurrences))
83 A1 --- f_Clumpy [J] J = Jellyfish candidate
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Note (1): Errors corresponding to adopting different conversion factors
for F24 microns to F8-1000um are ∼10-20%.
Note (2): For galaxies with Rhalf>1kpc, Source Extractor measurements of
the error on their spheroid radii are ∼1-8%.
Note (3): Magnitudes are observed-frame.
Note (4): See Tran+ (2009ApJ...705..809T 2009ApJ...705..809T) for errors in mass calculation.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 07-Sep-2017