J/MNRAS/496/3841 K-CLASH galaxy cluster members at 0.3<z<0.6 (Vaughan+, 2020)
K-CLASH: Strangulation and ram pressure stripping in galaxy cluster members at
0.3<z<0.6.
Vaughan S.P., Tiley A.L., Davies R.L., Prichard L.J., Croom S.M.,
Bureau M., Stott J.P., Bunker A., Cappellari M., Ansarinejad B.,
Jarvis M.J.
<Mon. Not. R. Astron. Soc., 496, 3841-3861 (2020)>
=2020MNRAS.496.3841V 2020MNRAS.496.3841V (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Infrared
Keywords: galaxies: clusters: general - galaxies: evolution - galaxies: ISM
Abstract:
Galaxy clusters have long been theorized to quench the star formation
of their members. This study uses integral-field unit observations
from the K-band MultiObject Spectrograph (KMOS) - Cluster Lensing And
Supernova survey with Hubble (CLASH) survey (K-CLASH) to search for
evidence of quenching in massive galaxy clusters at redshifts
0.3<z<0.6. We first construct mass-matched samples of exclusively
star-forming cluster and field galaxies, then investigate the spatial
extent of their Hα emission and study their interstellar medium
conditions using emission line ratios. The average ratio of Hα
half-light radius to optical half-light radius (re,Hα/re,Rc)
for all galaxies is 1.14±0.06, showing that star formation is taking
place throughout stellar discs at these redshifts. However, on
average, cluster galaxies have a smaller re,Hα/re,Rc ratio
than field galaxies: <re,Hα/re,Rc> =0.96±0.09 compared to
1.22±0.08 (smaller at a 98 per cent credibility level). These values
are uncorrected for the wavelength difference between Hα
emission and Rc-band stellar light but implementing such a
correction only reinforces our results. We also show that whilst the
cluster and field samples follow indistinguishable mass-metallicity
(MZ) relations, the residuals around the MZ relation of cluster
members correlate with cluster-centric distance; galaxies residing
closer to the cluster centre tend to have enhanced metallicities
(significant at the 2.6σ level). Finally, in contrast to
previous studies, we find no significant differences in electron
number density between the cluster and field galaxies. We use simple
chemical evolution models to conclude that the effects of disc
strangulation and ram-pressure stripping can quantitatively explain
our observations.
Description:
The K-CLASH survey design, data reduction procedures, and sample
properties are introduced and described in Paper 1 (Tiley et al.
2020MNRAS.496..649T 2020MNRAS.496..649T).
KMOS is a multiobject near-infrared spectrograph mounted at the
Nasmyth focus of Unit Telescope 1 at the European Southern
Observatory's (ESO) VLT, Cerro Paranal, Chile. K-CLASH observations
were conducted with KMOS in the IZ band between 2016 and 2018
(proposal IDs 097.A-0397, 098.A-0224, 099.A-0207, and 0100.A-0296).
The wavelength coverage in the IZ band is from 0.779 to 1.079µm,
corresponding to rest-frame Hα emission from z=0.19 to z=0.64.
The target fields were chosen to be the four massive galaxy clusters
MACS 2129 (z=0.589), MACS 1311 (z=0.494), MACS 1931 (z=0.352), and MS
2137 (z=0.313). These clusters were selected from the full CLASH
sample (https://archive.stsci.edu/prepds/clash/) to be observable from
the VLT and to be at redshifts where Hα emission from cluster
members lies between atmospheric telluric absorption bands and strong
night sky emission-line features.
In total, 282 galaxies were observed across the four clusters. We
detected stellar continuum and/or ionized-gas emission (from the
Hα and/or [NII] lines) in 243 galaxies.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 576 282 Table of Measurements
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Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID Galaxy ID
7- 20 A14 --- Name Galaxy name (Cluster+ID)
22- 32 F11.7 deg RAdeg Right ascension (J2000)
34- 45 F12.8 deg DEdeg Declination (J2000)
47- 54 A8 --- Cluster Observation field the galaxy is
located in (MACS1311, MACS1931,
MACS2129 or MS2137)
56- 69 F14.12 --- z Spectroscopic redshift from the
Hα line
71 I1 --- Halpha [0/1] Indicates if we detect
Hα in either the 0.6", 1.2"
or 2.4" aperture at a S/N ratio
greater than 5
73 I1 --- Csample [0/1] Indicates if the galaxy is a
member of the cluster sample
75 I1 --- Fsample [0/1] Indicates if the galaxy is a
member of the mass-matched field
sample
77 I1 --- AGN [0/1] Indicates if the galaxy
contains an AGN
79- 95 E17.12 10-7W/arcsec IHa ?=0 Integrated Hα flux in a
0.6" diameter aperture
97- 113 E17.12 10-7W/arcsec e_IHa ?=0 Error on IHa
115- 133 F19.16 [Msun] logMass Logarithm of the stellar mass
derived from the SED fitting
135- 157 F23.16 km/s vdiff Velocity difference to cluster
redshift
159- 178 F20.16 arcsec Rp ?=0 Projected radius from cluster
centre
180- 197 F18.16 --- Rp/R200 ?=0 Projected radius scaled to the
cluster R200 value
199- 213 F15.10 arcsec reHa ?=-999 Half light radius from the
Hα image (1)
215- 229 F15.10 arcsec reRc ?=-999 Half light radius from the
Rc band image (2)
231- 247 F17.12 --- reHa/reRc ?=-999 Ratio of effective radii
re,Hα/re,Rc
249 I1 --- qsize [0/1] Indicates if the size
measurement is reliable (3)
251- 262 F12.7 --- chi2Ha ?=-999 Reduced chi-squared from the
Hα image fitting
264- 273 F10.6 --- chi2Rc Reduced chi-squared from the Rc
band image fitting
275- 293 E19.13 --- S/Nimg ?=-999 Average S/N from within re
in the Hα image
295- 304 F10.6 --- n ?=-99 Best-fitting Sersic index
uncertainty
306- 316 F11.7 --- e_n ?=-99 Error on n
318- 332 F15.11 --- S/NHa ?=0 S/N of the Hα line in a
spectrum integrated in a 2.4"
diameter aperture
334- 352 E19.13 10-7W/arcsec FHa ?=-999 Hα flux measured by
ppxf from a 2.4" diameter aperture
354- 372 E19.13 10-7W/arcsec e_FHa ?=-999 Error on FHa
374- 392 E19.13 10-7W/arcsec FNII ?=-999 Flux in the [NII] line
measured by ppxf from a 2.4"
diameter aperture
394- 412 E19.13 10-7W/arcsec e_FNII ?=-999 Error on FNII
414- 432 E19.13 --- SIIratio ?=-999 Ratio of the [SII] lines
434- 452 E19.13 --- e_SIIratio ?=-999 Error on SIIratio
454- 472 E19.13 10-7W/arcsec FSII ?=-999 Total [SII] flux measured by
ppxf from a 2.4" diameter aperture
474- 492 E19.13 10-7W/arcsec e_FSII ?=-999 Error on FSII
494- 512 E19.13 --- chi2 ?=-999 Reduced chi-squared from the
ppxf fit
514- 532 E19.13 km/s vdisp ?=-999 Velocity dispersion from the
ppxf fit
534- 554 F21.16 [-] 12+log(O/H) ?=-999 Gas-phase metallicity
measured in a 2.4" diameter
aperture using the [NII]/Hα
ratio
556- 576 F21.16 [-] e_12+log(O/H) ?=-999 Error on 12+log(O/H)
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Note (1): We fit models to the galaxy Hα surface brightness distribution,
then measure re from a curve-of-growth analysis (integrating the
best-fitting model in a circular aperture; See Section 3.3)
Note (2): We fit models to the galaxy image then measure re from a
curve-of-growth analysis (integrating the best-fitting model in a
circular aperture; see Section 3.4)
Note (3): Indicates if the galaxy meet the criteria described in Section 3.5
such that its size measurement is considered reliable
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History:
From electronic version of the journal
References:
Tiley et al., Paper I 2020MNRAS.496..649T 2020MNRAS.496..649T
(End) Ana Fiallos [CDS] 17-Jul-2023