J/MNRAS/430/3453 Radial velocities in A1914 (Barrena+, 2013)
The puzzling merging cluster Abell 1914: new insights from the kinematics of
member galaxies.
Barrena R., Girardi M., Boschin W.
<Mon. Not. R. Astron. Soc., 430, 3453-3464 (2013)>
=2013MNRAS.430.3453B 2013MNRAS.430.3453B
ADC_Keywords: Clusters, galaxy ; Galaxies, photometry ; Radial velocities
Keywords: galaxies: clusters: general -
galaxies: clusters: individual: Abell 1914
Abstract:
We analyse the dynamical state of Abell 1914, a merging cluster
hosting a radio halo, quite unusual for its structure. Our study
considers spectroscopic data for 119 galaxies obtained with the
Italian Telescopio Nazionale Galileo. We select 89 cluster members
from spatial and velocity distributions. We also use photometry
Canada-France-Hawaii Telescope archives. We compute the mean cluster
redshift, =0.168, and the velocity dispersion which shows a high
value, σV=1210+125-110km/s. From the 2D analysis we find
that Abell 1914 has a north-east (NE)-south-west (SW) elongated
structure with two galaxy clumps, that mostly merge in the plane of
the sky. Our best but very uncertain estimate of the velocity
dispersion of the main system is σV, main ∼1000km/s. We estimate
a virial mass Msys=1.4-2.6x1015h-170M☉ for the whole
system. We study the merger through a simple two-body model and find
that data are consistent with a bound, outgoing substructure observed
just after the core crossing. By studying the 2D distribution of the
red galaxies, photometrically selected, we show that Abell 1914 is
contained in a rich large-scale structure, with two close companion
galaxy systems, known to be at z∼0.17. The system at SW supports the
idea that the cluster is accreting groups from a filament aligned in
the NE-SW direction, while that at NW suggests a second direction of
the accretion (NW-SE). We conclude that Abell 1914 well fits among
typical clusters with radio haloes. We argue that the unusual radio
emission is connected to the complex cluster accretion and suggest
that Abell 1914 resembles the well-known nearby merging cluster Abell
754 for its particular observed phenomenology.
Description:
We performed observations of A1914 using Device Optimized for the Low
Resolution (DOLORES) multi-object spectrograph at the TNG telescope in
2010 March. We used the LR-B grism, which provides a dispersion of
187Å/mm. DOLORES works with a 2048x2048 pixels E2V CCD. The pixel
size is 13.5um. We retrieved a total of four multi-object spectroscopy
(MOS) masks containing 146 slits. We exposed 3600s for each mask.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 47 119 Radial velocities of 119 galaxies in the field
of Abell 1914
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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 A1 --- Mm [m] m for galaxy members
3- 5 I3 --- Seq [1/119] Sequential number
6 A1 --- n_Seq [+*] indicates galaxies BCG1 (+) BCG2 (*)
8- 9 I2 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 18 F5.2 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs Declination (J2000)
32- 36 F5.2 mag rmag ?=- MEGA r magnitude (from the Canadian
Astronomy Data Centre (CADC) Megapipe archive
(Gwyn, 2009, ASP Conf. Ser. Vol. 411, p.123)
38- 43 I6 km/s RV Radial velocity (cz)
45- 47 I3 km/s e_RV rms uncertainty on RV
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 16-Apr-2014