J/A+A/699/A105 Redshift catalogue for SMACS J0723.3-7327 (Amrutha+, 2025)
Multi-object spectroscopic survey of the massive galaxy cluster
SMACS J0723.3-7327.
Amrutha B.M., Haines C.P., Demarco R., Nonino M., Finoguenov A., Rescigno U.
<Astron. Astrophys. 699, A105 (2025)>
=2025A&A...699A.105A 2025A&A...699A.105A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; Redshifts
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: general - galaxies: clusters: individual: SMACS J0723.3-7327
Abstract:
We present a new wide-field spectroscopic survey of the galaxy cluster
SMACS J0723.3-7327 at z∼0.39, with the aim of mapping the
large-scale structure around this massive cluster. We also aim to
detect infalling galaxy groups in combination with XMM-Newton and
eROSITA X-ray data, while studying the evolution and transformation of
cluster galaxies out to ∼2r200.
We carried out new multi-slit spectroscopic observations of SMACS
J0723-3-7327 with the IMACS f/2 instrument on the 6.5m Magellan-Baade
telescope, obtaining spectra for 193 galaxies selected using deep
near-infrared (NIR) photometry from the Galaxy Clusters at VIRCAM
(GCAV) survey. We examined the infall pattern of galaxies in the
caustic diagram out to ∼2r200 and used it to identify 93 cluster
members from our sample as being located within the caustic curves.
Incorporating redshifts from previous studies of the cluster core, we
produced a catalogue of 150 spectroscopically-confirmed cluster
members.
We measured a central cluster redshift of z=0.3910±0.0007 and a
velocity dispersion of σV=1431±150km/s for galaxies within
r200. We found sub-structures within the velocity distribution
function and a filamentary structure passing SE-NW through the
cluster, likely related to the highly elongated mass distribution and
X-ray emission seen in the central regions of the cluster. Using an
optical colour-colour separation, we determine the fraction of
star-forming galaxies as a function of cluster-centric radius out to
5r200 using photometric data, finding it consistently lower compared
to coeval field galaxies even at 5r200. We identified a number of
clumps of red galaxies in the cluster infall regions, suggestive of
infalling groups in which galaxies could be undergoing pre-processing,
even if we were unable to detect any associated X-ray emission in the
XMM or eROSITA data.
This work confirms the dynamical complexity of cluster SMACS
J0723.3-7327 and the surrounding large-scale structure, similar to
that seen for other massive clusters at z∼0.4. Further spectroscopic
analyses across larger cluster-centric distances are essential to
comprehensively assess the dynamical state of the cluster and
investigate how environmental mechanisms influence star formation
quenching in galaxies at varying radial distances.
Description:
Multi-object spectroscopy of the massive galaxy cluster
SMACS J0723.3-7327 at z=0.39 was carried out with the IMACS f/2
instrument on the 6.5m Magellan-Baade telescope at the Las Campanas
Observatory in Chile in March 2023, as part of CNTAC program
CN2023A-16 (PI: Amrutha Belwadi). This catalogue contains the
resulting spectroscopic redshifts obtained for 193 galaxies across the
27'x27' IMACS f/2 field-of-view, of which 93 have been confirmed as
members of the cluster SMACS J0723.3-7327.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 88 193 Redshift catalogue for SMACS J0723.3-7327
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See also:
J/A+A/666/L9 : SMACS J0723.3-7327 first JWST observations (Caminha+, 2022)
J/ApJ/940/L24 : JWST 7.7um sources in SMACS J0723.3-7327 field (Iani+, 2022)
J/A+A/670/A96 : SMACS J0723.3-7327 eROSITA and Chandra images (Liu+, 2023)
J/ApJ/946/L40 : Galaxies in JWST obs. of SMACS J0723.3-7327 (Langeroodi+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension (J2000)
12- 20 F9.5 deg DEdeg Declination (J2000)
22- 29 F8.4 mag rmag r-band magnitude (AB) of galaxy
30- 37 F8.4 --- z Spectroscopic redshift of galaxy
38- 45 F8.4 --- e_z Uncertainty in the spectroscopic redshift
48- 49 A2 --- Type [Q SF *] Spectroscopic class,
Q = Quiescent, SF = StarForming
52 I1 --- ClMem [0/1] Cluster member (=1) or not (=0)
55 I1 --- q_z Quality of spectroscopic redshift
57- 64 F8.4 mag Kmag K-band magnitude (AB) of galaxy
65- 72 F8.4 mag J-K J-K colour (AB) of galaxy
73- 80 F8.4 --- zph Photometric redshift
81- 88 F8.4 --- e_zph C Uncertainty in the photometric redshift
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Acknowledgements:
Christopher Haines, chris.haines(at)uda.cl
(End) Patricia Vannier [CDS] 17-May-2025