J/AJ/113/1939 VLA Survey of Hercules cluster. I. (Dickey 1997)
A VLA survey of the Hercules cluster. I. The H I data
Dickey J. M.
<Astron. J. 113, 1939 (1997)>
=1997AJ....113.1939D 1997AJ....113.1939D
ADC_Keywords: Clusters, galaxy ; H I data
Abstract:
This paper presents results from a survey of lambda 21-cm emission
from galaxies in the Hercules cluster, A2151 and A2147. Four VLA
primary beam areas were covered, a total area of 0.9 square degrees,
including some 120 spiral galaxies brighter than 17.5m. The velocity
resolution is 44km/s, the angular resolution 25". The detection
threshold at field center is 2.6x10^8 h^{-2}M☉ in H I mass or
about 1.8x1020cm-2^ in column density. There are 61 galaxies
detected in H I, of which about 25 had been previously detected at
lambda 21-cm. About ten of the detections correspond to galaxies that
are very faint in the optical, mE≥18 or M≥-17mag-5logh. Some of
these low surface brightness galaxies have very extended H I disks,
with r≥15kpc. The abundance of H I is a strong function of position
in the cluster, with galaxies in the south and west showing hardly any
gas, and galaxies in the north and east of A2151 frequently having
massive, extended gas disks. The morphology of the remnants of gas in
galaxies in the south and west suggests that the intracluster medium
is responsible for their H I deficiency, but there are also several
dramatic galaxy mergers in progress.
(c) 1997 American Astronomical Society.
Description:
The channel maps for the Hercules cluster are stored in 63
Encapsulated Postscript files named fig36.eps, fig37.eps, ...
fig98.eps. For all figures, the contour levels are as in figure 15 in
the printed paper.
Objects:
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RA (2000) DE Designation(s)
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16 05.2 +17 45 ACO 2151 = Hercules cluster
16 02.3 +15 55 ACO 2147
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 97 63 Galaxies detected in H I
table3.dat 34 372 Channel map centers
eps/* . 63 Velocity channel maps
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- File Name of the file in eps sub-directory
11- 16 A6 --- Alias Galaxy alias (1)
18- 32 A15 --- Name Other name
34- 35 I2 h RAh Right ascension (B1950)
37- 38 I2 min RAm Right ascension (B1950)
40- 44 F5.2 s RAs Right ascension (B1950)
46- 47 I2 deg DEd Declination (B1950)
49- 50 I2 arcmin DEm Declination (B1950)
52- 55 F4.1 arcsec DEs Declination (B1950)
57- 61 I5 km/s V0 Center velocity
63- 65 I3 km/s DV Width velocity
67- 69 F3.1 --- fpb Primary beam attenuation factor
71- 73 I3 pix Area Area used for H I mass determinations (2)
75- 79 F5.1 10+8solMass MHI H I mass obtained from spectra integrals
81- 85 F5.1 10+8solMass Mext Maximum total H I mass obtained by extending
the area
87- 91 F5.1 10+8solMass Mpeak H I mass contained within the central beam area
93- 97 F5.1 10+8solMass Mint Mass determined form the integrated flux
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Note (1): Fields 'ne' (northeast), 'ce' (center), and 'sw' (southeast) cover
different areas of A2151, while field '47' covers the center of
A2147.
Note (2): 1 pix = 6"
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Alias Galaxy alias
8- 12 I5 km/s cz Center velocity of the channel
15- 17 I3 arcsec oRA *Right ascension offset
20- 22 I3 arcsec oDE *Declination offset
25- 28 F4.1 10+8solMass Mpeak *Peak H I mass in the channel
31- 34 F4.1 10+8solMass Mint *Integrated H I mass in the channel
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Note on oRA, oDE:
Offsets of the fitted peak position from the H I centroid position
as given in table2.dat.
Note on Mpeak, Mint:
The peak and integrated H I mass contained in the velocity channel
similar to the last two columns of table2.dat.
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Origin: AAS CD-ROM series, Volume 9, 1997 Lee Brotzman [ADS] 29-Aug-1997
History: table2.dat was prepared via OCR at CDS.
(End) Patricia Bauer [CDS] 04-Feb-1998