J/MNRAS/442/2216 Redshifts of galaxies in Abell 1351 field (Barrena+, 2014)
The structure of Abell 1351: a bimodal galaxy cluster with peculiar diffuse
radio emission.
Barrena R., Girardi M., Boschin W., De Grandi S., Rossetti M.
<Mon. Not. R. Astron. Soc., 442, 2216-2227 (2014)>
=2014MNRAS.442.2216B 2014MNRAS.442.2216B
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Radial velocities
Keywords: galaxies: clusters: general - galaxies: clusters: individual
Abstract:
We aim to review the internal structure and dynamics of the Abell 1351
cluster, shown to host a radio halo with a quite irregular shape. Our
analysis is based on radial velocity data for 135 galaxies obtained at
the Telescopio Nazionale Galileo. We combine galaxy velocities and
positions to select 95 cluster galaxy members and analyse the internal
dynamics of the whole cluster. We also examine X-ray data retrieved
from Chandra and XMM archives. We measure the cluster redshift,
=0.325, the line-of-sight (LOS) velocity dispersion,
σV∼1500km/s, and the X-ray temperature, kT∼9keV. From both X-ray
and optical data independently, we estimate a large cluster mass, in
the 1-4x1015h70-1M☉. We attribute the extremely high value
of σV to the bimodality in the velocity distribution. We find
evidence of a significant velocity gradient and optical 3D
substructure. The X-ray analysis also shows many features in favour of
a complex cluster structure, probably supporting an ongoing merger of
substructures in Abell 1351. The observational scenario agrees with
the presence of two main subclusters in the northern region, each with
its brightest galaxy (BCG1 and BCG2), detected as the two most
important X-ray substructures with a rest-frame LOS velocity
difference of ΔVrf∼2500km/s and probably being in large
part aligned with the LOS. We conclude that Abell 1351 is a massive
merging cluster. The details of the cluster structure allow us to
interpret the quite asymmetric radio halo as a 'normal' halo plus a
southern relic, strongly supporting a previous suggestion based only
on inspection of radio and preliminary X-ray data.
Description:
Multi-object spectroscopic (MOS) observations of A1351 were carried
out at the TNG on 2010 March 10. We used DOLORES/MOS with the LR-B
Grism 1, yielding a dispersion of 187Å/mm. We used the 2048x2048
pixel E2V CCD, with a pixel size of 13.5um. In total, we observed
four MOS masks including 143 slits. For each mask, the exposure time
was 3x1800s.
We had already observed A1351 field with the Wide Field Camera (WFC),
mounted at the prime focus of the 2.5m INT telescope. We took
exposures of 9x600s and 9x300s in B and R Harris filters in
photometric conditions and 1.2-arcsec seeing. However, we used
SDSS-DR7 data because a greater number of photometric bands are
available, which allows an accurate colour analysis. INT and SDSS-DR7
photometric data are very similar. The completeness magnitude is
r'=20.8.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 135 Radial velocities of 135 galaxies in the field
of A1351
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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 [1/135] Sequential galaxy number
4 A1 --- n_Seq [*n] BCG or non-member galaxy (1)
6- 7 I2 h RAh Right ascension (J2000)
9- 10 I2 min RAm Right ascension (J2000)
12- 16 F5.2 s RAs Right ascension (J2000)
18 A1 --- DE- Declination sign (J2000)
19- 20 I2 deg DEd Declination (J2000)
22- 23 I2 arcmin DEm Declination (J2000)
25- 28 F4.1 arcsec DEs Declination (J2000)
30- 34 F5.2 mag r'mag r' magnitude
36- 41 I6 km/s cz [18306/404991] Radial velocity
43- 45 I3 km/s e_cz [28/500] rms uncertainty on cz
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Note (1): Notes as follows:
* = the two brightest cluster members BCG1 (ID. 66) and BCG2 (ID 74);
see the text)
n = non-member galaxies
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Mar-2015