J/AJ/151/78 Jellyfish galaxy candidates in galaxy clusters (Poggianti+, 2016)
Jellyfish galaxy candidates at low redshift.
Poggianti B.M., Fasano G., Omizzolo A., Gullieuszik M., Bettoni D.,
Moretti A., Paccagnella A., Jaffe Y.L., Vulcani B., Fritz J., Couch W.,
D'Onofrio M.
<Astron. J., 151, 78 (2016)>
=2016AJ....151...78P 2016AJ....151...78P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, optical ; Redshifts
Keywords: atlases - galaxies: clusters: intracluster medium -
galaxies: evolution - galaxies: groups: general - galaxies: ISM -
galaxies: star formation
Abstract:
Galaxies that are being stripped of their gas can sometimes be
recognized from their optical appearance. Extreme examples of stripped
galaxies are the so-called "jellyfish galaxies" that exhibit tentacles
of debris material with a characteristic jellyfish morphology. We have
conducted the first systematic search for galaxies that are being
stripped of their gas at low-z (z=0.04-0.07) in different
environments, selecting galaxies with varying degrees of morphological
evidence for stripping. We have visually inspected B- and V-band
images and identified 344 candidates in 71 galaxy clusters of the
OMEGAWINGS+WINGS sample and 75 candidates in groups and lower mass
structures in the PM2GC sample. We present the atlas of stripping
candidates and a first analysis of their environment and their basic
properties, such as morphologies, star formation rates and galaxy
stellar masses. Candidates are found in all clusters and at all
clustercentric radii, and their number does not correlate with the
cluster velocity dispersion σ or X-ray luminosity LX.
Interestingly, convincing cases of candidates are also found in groups
and lower mass halos (1011-1014M☉), although the physical
mechanism at work needs to be securely identified. All the candidates
are disky, have stellar masses ranging from log M/M☉<9 to >11.5
and the majority of them form stars at a rate that is on average a
factor of 2 higher (2.5σ) compared to non-stripped galaxies of
similar mass. The few post-starburst and passive candidates have weak
stripping evidence. We conclude that disturbed morphologies suggestive
of stripping phenomena are ubiquitous in clusters and could be present
even in groups and low mass halos. Further studies will reveal the
physics of the gas stripping and clarify the mechanisms at work.
Description:
WIde-field Nearby Galaxy-cluster Survey (WINGS) is a large survey
targeting 76 clusters of galaxies selected on the basis of their X-ray
luminosity (Ebeling et al. 1996, Cat. J/MNRAS/281/799; Ebeling et al.
1998, Cat. J/MNRAS/301/881; Ebeling et al. 2000, Cat.
J/MNRAS/318/333), covering a wide range in cluster masses
(σ=500-1200+km/s, logLX=43.3-45erg/s, Fasano et al.
2006A&A...445..805F 2006A&A...445..805F). The original WINGS data set consisted of B and V
deep photometry of a 34'*34' field of view with the WFC@INT and the
WFC@2.2mMPG/ESO (Varela et al. 2009, Cat. J/A+A/497/667),
spectroscopic follow-ups with 2dF@AAT and WYFFOS@WHT (Cava et al.
2009, Cat. J/A+A/495/707), plus J and K imaging with WFC@UKIRT
(Valentinuzzi et al. 2009, Cat. J/A+A/501/851) and some U-band imaging
(Omizzolo et al. 2014, Cat. J/A+A/561/A111). This database is
presented in Moretti et al. 2014A&A...564A.138M 2014A&A...564A.138M and has been employed
for a number of studies (see
https://sites.google.com/site/wingsomegawings/).
OmegaCAM-VST observations of WINGS galaxy clusters (OMEGAWINGS) is a
recent extention of this project, that quadruples the area covered
(1deg2) and allows to reach up to ∼2.5 cluster virial radii.
OMEGAWINGS is based on two OmegaCAM@VST GTO programs for 46 WINGS
clusters: a B and V campaign completed in P93, and an ongoing u-band
programme. The B and V data, the data reduction and the photometric
catalogs are presented in Gullieuszik et al. 2015 (Cat.
J/A+A/581/A41). Spectra are obtained with AAOmega@AAT on the OmegaCAM
field. So far, we have secured high quality spectra for ∼30 OMEGAWINGS
clusters, reaching very high spectroscopic completeness levels for
galaxies brighter than V=20 from the cluster cores to their periphery
(A. Moretti et al. 2016, in preparation). Galaxies are considered
cluster members if they are within 3σ from the cluster redshift.
The mean redshift uncertainty, computed from the differences between
WINGS and OMEGAWINGS redshift values of repeated objects, is
Δz=0.0002.
For this paper we consider the 41 OMEGAWINGS clusters with an OmegaCAM
B and/or V-band seeing ≤1.2arcsec, listed in Table1. To complete
the search within the WINGS sample, we used the old WINGS images for
other 31 clusters not observed with OmegaCAM (Table1).
The reference comparison field sample for WINGS and OMEGAWINGS is the
Padova Millennium Galaxy and Group Catalog (PM2GC; Calvi et al. 2011,
Cat. J/MNRAS/416/727), built from the Millennium Galaxy Catalogue
(MGC; Liske et al. 2003, Cat. VII/240), a deep 38deg2 INT B-imaging
survey with a highly complete spectroscopic follow-up (96% at B=20,
Driver et al. 2005, Cat. VII/240).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 35 71 *OMEGAWINGS (O) and WINGS (W) clusters
table3.dat 86 344 *OMEGAWINGS and WINGS stripping candidates
table4.dat 57 75 *PM2GC stripping candidates
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Note on table1.dat table3.dat:
WINGS = WIde-field Nearby Galaxy-cluster Survey (Fasano et al.
2006A&A...445..805F 2006A&A...445..805F);
OMEGAWINGS = OmegaCAM-VST observations of WINGS galaxy clusters (Gullieuszik
et al. 2015, Cat. J/A+A/581/A41).
Note on table4.dat:
PM2GC = Padova-Millennium Galaxy and Group Catalogue (Calvi et al. 2011,
Cat. J/MNRAS/416/727).
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See also:
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
VII/240 : Millennium Galaxy Catalogue (Liske+, 2003)
J/A+A/581/A41 : OmegaWINGS photometry of gal. clusters (Gullieuszik+, 2015)
J/A+A/561/A111 : U-band photometry of 17 WINGS clusters (Omizzolo+, 2014)
J/ApJ/762/77 : PM2GC sample surface photometry (Poggianti+, 2013)
J/MNRAS/432/3141 : Morphological classification of PM2GC gal. (Calvi+, 2013)
J/MNRAS/420/926 : Morphology of galaxies in WINGS clusters (Fasano+, 2012)
J/MNRAS/416/727 : Padova-Millennium Galaxy and Group Catalogue (Calvi+, 2011)
J/A+A/526/A45 : WINGS-SPE II catalog (Fritz+, 2011)
J/A+A/501/851 : WINGS photometry of 28 galaxy clusters (Valentinuzzi+, 2009)
J/A+A/497/667 : WINGS: Deep optical phot. of nearby clusters (Varela+, 2009)
J/A+A/495/707 : WINGS spectroscopy of 48 galaxy clusters (Cava+, 2009)
J/MNRAS/318/333 : Extended ROSAT Bright Cluster Sample (Ebeling+ 2000)
J/MNRAS/301/881 : The ROSAT brightest cluster sample - I. (Ebeling+, 1998)
J/MNRAS/281/799 : XBACs, the sample (Ebeling+, 1996)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Sample [OW] Sample (O=OMEGAWINGS or W=WINGS) (1)
3- 9 A7 --- Cluster Name of the galaxy cluster
11 A1 --- f_Cluster [*] Flag on Cluster: *=member of Shapley
supercluster (2)
13- 18 F6.4 --- z [0.039/0.07] Redshift
20- 23 I4 km/s sigma [353/1309]? Cluster velocity dispersion σ
25- 26 I2 km/s e_sigma [10/97]? Uncertainty in σ
28- 32 F5.2 [10-7J/s] logLx [43.5/45.1] Log(LX) in 0.1-2.4keV band
34- 35 I2 --- Nc [1/15] Number of stripping candidates
(spectroscopic member or possible member,
i.e., without redshift)
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Note (1): WINGS (Cava et al. 2009, Cat. J/A+A/495/707) or OMEGAWINGS (Moretti et
al. in prep.).
Note (2): See Shapley in Simbad database.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- Galaxy Jellyfish galaxy identifier (JW prefix for WINGS
clusters and JO for OMEGAWINGS clusters) (1)
7- 13 A7 --- Cluster Galaxy cluster
15 A1 --- Img [OW] Inspected image: O=OMEGAWINGS (OmegaCAM)
or W=WINGS (INT or 2.2m) (2)
17 A1 --- Band [BV] Inspected image bandpass (B or V)
19- 29 F11.7 deg RAdeg Right Ascension decimal degrees (J2000)
31- 41 F11.7 deg DEdeg Declination decimal degrees (J2000)
43 I1 --- J [1/5] JClass (visual evidence for stripping
signatures in the optical) (G1)
45- 73 A29 --- n_Galaxy Comments on Jellyfish identifier
75- 76 I2 --- Mm [-1/2] Cluster membership (1=member,
0=non-member, -1=redshift unknown) (3)
78- 84 F7.5 --- z [0.0074/0.27]? Redshift
86 A1 --- r_z Source for redshift (1=WINGS or OMEGAWINGS,
2=NED, 3=SDSS, or 4=average NED and SDSS) (4)
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Note (1): Galaxies that are being stripped of their gas can sometimes be
recognized from their optical appearance. Extreme examples of stripped
galaxies are the so-called "jellyfish galaxies" that exhibit tentacles of
debris material with a characteristic jellyfish morphology.
Note (2):
WINGS data set of B and V deep photometry of a 34'*34' field of view with
the WFC@INT and the WFC@2.2mMPG/ESO (Varela et al. 2009,
Cat. J/A+A/497/667);
OMEGAWINGS is based on two OmegaCAM@VST GTO programs for 46 WINGS clusters,
including a B and V campaign completed in P93.
Note (3): Cluster membership:
1 = member;
0 = non-member;
2 = member of structure along the line of sight;
-1 = redshift unknown.
Note (4): Source of redshift:
1 = WINGS (Cava et al. 2009, Cat. J/A+A/495/707) or OMEGAWINGS (Moretti et
al. in prep.);
2 = NED (https://ned.ipac.caltech.edu/);
3 = SDSS (see SDSS-DR9 in Cat. V/139);
4 = Average NED and SDSS.
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- MGC [648/96949] Galaxy identifier in Millennium Galaxy
Catalog (MGC; Liske et al. 2003, Cat. VII/240)
7- 15 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
17- 24 F8.5 deg DEdeg Declination in decimal degrees (J2000)
26 I1 --- J [1/4] JClass (visual evidence for stripping
signatures in the optical) (G1)
28- 34 F7.5 --- z [0.04/0.07] MGC redshift (Liske et al. 2003,
Cat. VII/240)
36- 57 A22 --- Comment Comments on visual appearance
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Global Notes:
Note (G1): Ranges from 5 (strongest) to 1 (weakest).
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History:
From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 13-Oct-2016