J/ApJS/272/47 Magellan sp. obs. of galaxies with z∼0.95 in UDS (Lee+, 2024)
Multiobject spectroscopy of galaxy clusters at z∼0.95 in the Ultra Deep Survey
field with different star formation properties and large-scale environments.
Lee S.-K., Im M., Park B., Hyun M., Paek I., Kim D.
<Astrophys. J. Suppl. Ser., 272, 47 (2024)>
=2024ApJS..272...47L 2024ApJS..272...47L
ADC_Keywords: Clusters, galaxy; Redshifts; Spectra, optical
Keywords: High-redshift galaxy clusters ; Galaxy clusters ;
Large-scale structure of the universe ; Galaxy evolution ;
High-redshift galaxies ; Cosmic web
Abstract:
While galaxy clusters are dominated by quiescent galaxies in the local
Universe, they show a wide range in quiescent galaxy fraction (QF) at
higher redshifts. Here we present the discovery of two galaxy clusters
at z∼0.95 with contrasting QFs despite having similar masses
(log(M200/M☉)∼14) and spectra and redshifts of 29 galaxies in
these clusters and 76 galaxies in the surrounding area. The clusters
are found in the Ultra Deep Survey field and confirmed through
multiobject spectroscopic observation using the Inamori Magellan Areal
Camera and Spectrograph on the Magellan telescope. The two clusters
exhibit QFs of 0.094-0.032+0.11 and 0.38-0.11+0.14,
respectively. Analysis of large-scale structures (LSSs) surrounding
these clusters finds that properties of these clusters are consistent
with the anticorrelation trend between the QF and the extent of
surrounding LSS, found in Lee+ 2019, J/MNRAS/490/135, which can be
interpreted as a result of the replenishment of young, star-forming
galaxies keeping the QF low when galaxy clusters are accompanied by
rich surrounding environments.
Description:
The Ultra Deep Survey (UDS) field carries a wealth of multiband
photometric data collected from various facilities across
approximately 0.8deg2. In this study, we utilize optical data from
the Subaru telescope, near-infrared (NIR) data from the United Kingdom
InfraRed Telescope (UKIRT), and mid-infrared (MIR) data from the
Infrared Array Camera (IRAC) on the Spitzer telescope.
See Section 2.1.
In Lee+ (2015ApJ...810...90L 2015ApJ...810...90L), we identified galaxy cluster candidates
within the redshift range of 0.5≤z≤2.0 in the UDS field. We selected
several of those cluster candidates for follow-up spectroscopic
observations, among which the observation and analysis of two z∼0.95
cluster candidates are presented in this paper.
We conducted observations of two galaxy cluster candidates and their
surrounding regions using the Inamori-Magellan Areal Camera and
Spectrograph (IMACS) on the Magellan/Baade telescope.
Employing the Magellan/IMACS f/2 camera, we performed MOS observations
on two occasions: first on 2016 August 27 (2016B semester), and
subsequently on 2019 August 31 (2019B semester).
See Section 2.2.
We provide a complete list of galaxies with measured spectroscopic
redshifts in Table 1.
We adopt a standard cosmology with
(Ωm,ΩΛ)=(0.3,0.7) and H0=70km/s/Mpc
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s) (z)
----------------------------------------------------------
02 16 12.9 -04 52 36 OD5 = UDS-OD5 (0.954)
02 16 14.8 -04 43 55 OD6 = UDS-OD5 (0.931)
----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This filespec1d_obj321954.fits
table1.dat 58 105 Spectroscopic redshift information from
Magellan/IMACS observation
table2.dat 11 105 The correction factors calculated in the
i'-band for each galaxy
tablea1.dat 32 2060 Flux-calibrated, slit-loss-corrected spectrum
of galaxy 314733
sp/* . 105 *Individual 1D flux-calibrated spectra in FITS
format -- Data behind Figure A1
--------------------------------------------------------------------------------
Note on sp/*: Please note that the provided spectra haven't undergone
slit-loss correction (refer to Section 2.2.5). For slit-loss
correction factors, please consult Table 2.
--------------------------------------------------------------------------------
See also:
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
J/A+A/345/419 : Star formation in early-type galaxies (Longhetti+ 1999)
J/ApJS/176/1 : Subaru/XMM-Newton deep survey (SXDS). II. (Furusawa+, 2008)
J/A+A/499/47 : Lick indices of EDCSN galaxies (Sanchez-Blazquez+, 2009)
J/ApJ/825/72 : Follow-up study of gal. in z>1 clusters (Alberts+, 2016)
J/MNRAS/490/135 : Galaxy clusters and groups at z∼1 (Lee+, 2019)
J/ApJ/890/7 : Environment of gal. in the 5 CANDELS fields (Chartab+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID [244417/350989] Galaxy ID
8- 15 F8.5 deg RAdeg [34/34.2] Right Ascension (J2000)
17- 24 F8.5 deg DEdeg [-5/-4.69] Declination (J2000)
26- 31 F6.4 --- zspec [0.76/1.11] Spectroscopic redshift
33- 33 A1 --- f_zspec Quality flag on zspec (1)
35- 41 A7 --- feature Redshift identification feature(s) (2)
43- 47 F5.3 --- zphot [0.84/0.99] Photometric redshift
49- 54 F6.3 mag Rmag [22.18/24.7] R-band AB magnitude
56- 58 A3 --- Cluster Associated cluster ID ("OD5" or "OD6")
--------------------------------------------------------------------------------
Note (1): Spectroscopic quality flag as follows:
a = Galaxies with secure redshift measurements based on clear
emission line(s) or absorption feature(s);
b = Galaxies where emission or absorption line(s) are faint.
Note (2): Redshift identification feature as follows:
1 = [O II];
2 = Hβ;
3 = Ca H&K;
4 = 4000Å break;
5 = Hδ;
6 = [O III];
7 = Hγ.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ID [244417/350989] Galaxy ID
8- 11 F4.2 --- Corr [1/8] Correction factor, the reciprocal of the
slit loss value from the i'-band analysis
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 F6.1 0.1nm lambda [5698/9816] Wavelength in Angstroms
8- 19 E12.5 10-17cW/m2/nm Flux [-3.5/2.7] Flux
in 10-17erg/s/cm2/Å
21- 32 E12.5 10-17cW/m2/nm e_Flux [0/0.005] Flux error
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Oct-2024