J/A+A/633/A108 Velocity field of the Lyra complex (Girardi+, 2020)
The velocity field of the Lyra complex.
Girardi M., Boschin W., De Grandi S., Longhetti M., Clavico S., Eckert D.,
Gastaldello F., Ghizzardi S., Nonino M., Rossetti M.
<Astron. Astrophys. 633, A108 (2020)>
=2020A&A...633A.108G 2020A&A...633A.108G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; Spectroscopy ; Radial velocities
Keywords: galaxies: clusters: individual: RXC J1825.3+3026 -
galaxies: clusters: individual: CIZA J1824.1+3029 -
galaxies: general - galaxies: kinematics and dynamics
Abstract:
The formation of cosmic structures culminates with the assembly of
galaxy clusters, a process that is quite different from cluster to
cluster. We present the study of the structure and dynamics of the
Lyra complex, consisting of the two clusters RXC J1825.3+3026 and CIZA
J1824.1+3029, which was very recently studied by using both X-ray and
radio data. This is the first analysis based on the kinematics of
member galaxies. New spectroscopic data for 285 galaxies were acquired
at the Italian Telescopio Nazionale Galileo and were used in
combination with PanSTARRS photometry. The result of our member
selection is a sample of 198 galaxies. For RXCJ1825 and CIZAJ1824 we
report the redshifts, z=0.0645 and z=0.0708, the first estimates of
velocity dispersion, sigmav=995-125+131km/s and
sigmav=700±50km/s, and of dynamical mass,
M200=1.1±0.4x1015M[sun and M200=4±0.11014M☉. The
past assembly of RXCJ1825 is traced by the two dominant galaxies,
which are both aligned with the major axis of the galaxy distribution
along the east-west direction, and by a minor northeast substructure.
We also detect a quite peculiar high velocity field in the southwest
region of the Lyra complex. This feature is likely related to a very
luminous galaxy, which is characterized by a high velocity. This
galaxy is suggested to be the central galaxy of a group that is in
interaction with RXCJ1825 according to very recent studies based on
X-ray and radio data. The redshift of the whole Lyra complex is
z=0.067. Assuming that the redshift difference between RXCJ1825 and
CIZAJ1824 is due to the relative kinematics, the projected distance
between the cluster centers is D∼1.3Mpc and the line-of-sight velocity
difference is ∼1750km/s. A dynamical analysis of the system shows that
the two clusters are likely to be gravitationally bound in a
pre-merger phase, and that CIZAJ1824 is moving toward RXCJ1825. Our
results corroborate a picture where the Lyra region is the place of a
very complex scenario of cluster assembly.
Description:
The table contains radial velocities and cluster membership of 285
galaxies analyzed in the paper. Multi-object spectroscopic
observations in the Lyra field were carried out at the the Italian
Telescopio Nazionale Galileo (TNG) in 2018 June. We used the
instrument Device Optimized for the Low Resolution (DOLORES) in
multi-object spectroscopy (MOS) mode with the LR-B Grism. In total, we
observed twelve MOS masks for a total of 390 slits. For nine masks,
the total exposure time was 3600s, and for three masks the exposure
time was 5400s. In February 2019, we took long-slit spectra for
another two galaxies (one of them is the bright radio galaxy ID. 039.)
Objects:
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RA (2000) DE Designation(s)
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18 25 20.0 +30 26 11.2 RXC J1825.3+3026
18 24 06.8 +30 29 32.5 CIZA J1824.1+3029
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 285 Velocity catalog of 285 spectroscopically
measured galaxies in field of Lyra complex
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See also:
J/A+A/630/A77 : Lyra system LoFAR and XMM images (Botteon+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/285] Sequential number
7 A1 --- Memb Membership
11- 12 I2 h RAh Right ascension (J2000.0)
14- 15 I2 min RAm Right ascension (J2000.0)
17- 21 F5.2 s RAs Right ascension (J2000.0)
25 A1 --- DE- Declination sign (J2000.0)
26- 27 I2 deg DEd Declination (J2000.0)
29- 30 I2 arcmin DEm Declination (J2000.0)
32- 35 F4.1 arcsec DEs Declination (J2000.0)
38- 42 F5.2 mag rmag [14.6/21.4]?=- Dereddened r-band Pan-STARRS
DR1 magnitudes
47- 52 I6 km/s HRV [16666/342844] Heliocentric radial velocity
57- 59 I3 km/s e_HRV [36/324] Uncertainty on HRV
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Acknowledgements:
Marisa Girardi, marisa.girardi(at)inaf.it
(End) Patricia Vannier [CDS] 06-Nov-2019