Документ взят из кэша поисковой машины. Адрес оригинального документа : http://hea-www.harvard.edu/~dburke/southern_sharc/ReadMe Дата изменения: Tue Jun 10 03:56:01 2003 Дата индексирования: Tue Oct 2 01:32:54 2012 Кодировка:

J/MNRAS/341/1093 The Southern SHARC catalogue (Burke+, 2003)
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The Southern SHARC Catalogue: a ROSAT survey for distant galaxy clusters
Burke D.J., Collins C.A., Sharples R.M., Romer A.K., Nichol R.C.

=2003MNRAS.341.1093B
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ADC_Keywords: Clusters, galaxy ; Redshifts ; Positional data ; X-ray sources
Keywords: catalogues ; surveys ; galaxies: clusters: general ;
X-rays: galaxies: clusters
Mission_Name: ROSAT

Description:
The Southern Serendipitous High-redshift Archival Cluster (SHARC) catalogue
is a X-ray selected catalogue of galaxy clusters detected in deep ROSAT
observations. The survey area is 17.7 deg^2 and is selected from long
(greater than 10 ks) ROSAT exposures with a declination < +20 deg and
excluding the Galactic plane (excluding galactic latitudes within the
range [-20,20] deg). Optical follow-up was performed to confirm the
presence of a galaxy cluster and measure its redshift.

The final catalogue contains 32 galaxy clusters with redshifts between
0.05 and 0.70 and X-ray luminosities between 7x10^35 W and 4x10^37 W. Above
a redshift of 0.3 - which forms the primary subsample of the survey - there
are 16 clusters; the X-ray luminosities of these clusters are all greater
than 2x10^36 W. All X-ray luminosities are quoted in the 0.5-2.0 keV band
and were calculated using an Einstein-de Sitter cosmology with H_0 set to
50 km/s/Mpc.

File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 173 32 The 32 clusters in the Southern SHARC sample
selfn.dat 20 1092 Selection function for the Southern SHARC survey
(as shown in Figure 7)
fields.dat 98 66 ROSAT observations used in the Southern SHARC
survey (Table A1)
extsrcs.dat 112 96 All extended X-ray sources detected by the
Southern SHARC survey (Table B1)
numflux.dat 21 32 Number-flux points for Southern SHARC sample
(Figure 14)
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See also:
J/ApJS/126/209 : The Bright SHARC Survey: The Cluster Catalog (Romer+, 2000)

Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Southern SHARC catalogue name
17- 18 I2 h Rah Right Ascension 2000 (hours)
20- 21 I2 min Ram Right Ascension 2000 (minutes)
23- 26 F4.1 s Ras Right Ascension 2000 (seconds)
28 A1 - DE- Declination 2000 (sign)
30- 31 I2 deg DEd Declination 2000 (degrees)
33- 34 I2 arcmin DEm Declination 2000 (minutes)
36- 39 F4.1 arcsec DEs Declination 2000 (seconds)
41- 46 I6 --- ROR ROSAT observation request
48- 51 F4.1 arcmin Sep Angular distance: cluster to field center
53- 57 F5.3 --- Redshift Redshift of cluster
59 I1 --- nGal *Number of gals used to measure Redshift
61- 65 F5.2 arcmin r80 Aperture radius used to measure nSrc
67- 69 I3 % pArea *Percentage of aperture used
71- 75 F5.1 --- nSrc *Number of source counts in aperture
77- 82 F6.4 ct/s Ctot *Total cluster count rate
84- 87 F4.2 10+24/m2 nH *neutral Hydrogen column density
89- 94 F6.2 10-14mW/m2 f14 *Total cluster flux (0.5-2.0 keV)
96-100 F5.3 --- fracLerr *Fractional luminosity error
102-105 F4.2 10+37W Lrosat *Total cluster luminosity (0.5-2.0 keV)
107-110 F4.2 10+37W Lemss *Total cluster luminosity (0.3-3.5 keV)
112 I1 --- QF *[1-3] Quality flag of radial profile
114-173 A60 --- Matches Matches with other cluster catalogues
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Note on nGal:
The cluster redshift (the Redshift column) is calculated as the average
of nGal galaxies.

Note on pArea:
Gives the area of the source aperture - as a percentage - left after
masking out contaminating sources.

Note on nSrc:
The number of source counts is calculated from the source aperture
after masking out contaminating sources. The estimated background signal
in the aperture has been accounted for.

Note on Ctot:
The total cluster count rate is calculated by extrapolating the measured
count rate to an infinite aperture. For clusters with pArea = 100, this
amounts to multiplying the measured count rate by 1.25. If pArea is less
than 100 then the conversion factor is larger to account for the signal
excluded due to the presence of contaminating sources.

Note on nH:
Values taken from the compilation of 1984ApJ...287..633M (Marshall &
Clark 1984).

Note on f14:
The total cluster flux was calculated from the Ctot value assuming
a 6 keV thermal bremmstrahlung spectrum and accounting for Galactic
absorption using the cross sections of Morrison & McCammon (1983).

Note on fracLerr:
The fractional luminosity error (delta L/L) is calculated from the
Poisson error on the number of source counts (nSrc) added, in
quadrature, to a 5 per cent error to account for uncertainties due
to the use of a single temperature in the count rate to flux to
luminosity conversion.

Note on Lrosat:
k-correction to convert observed 0.5-2.0 keV flux (f14) to
0.5-2.0 keV rest frame was calculated assuming a 6 keV thermal
bremsstrahlung spectrum.

Note on Lemss:
k-correction to convert observed 0.5-2.0 keV flux (f14) to
0.3-3.5 keV rest frame was calculated assuming a 6 keV thermal
bremsstrahlung spectrum.

Note on QF:
Indicates the quality flag of the radial profile of the cluster
as discussed in section 3.2 of J/MNRAS/341/1093.
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Byte-by-byte Description of file: selfn.dat
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Bytes Format Units Label Explanations
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1- 7 F7.3 [mW/m2] lFlux *log10(Flux)
9- 13 F5.3 [arcsec] lTheta *log10(Core radius)
15- 19 F5.2 deg2 Area Survey Area
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Note on lFlux:
The flux used is the total cluster flux (so does not include any loses due
to using a finite-sized aperture) and is given as log10(flux). The listed
value gives the center of the bin and the bin width is 0.07 log10(mW/m2).

Note on lTheta:
Gives the core radius of the cluster in arcseconds, and is given as
log10(core radius). The listed value gives the center of the bin and the
bin width is 0.07 log10(arcsec).
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Byte-by-byte Description of file: fields.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Field name
18- 23 I6 --- ROR ROSAT observation request
25- 27 A3 --- oSurveys Other surveys?
29- 33 I5 s Texp *Cleaned exposure time
35- 38 F4.2 10+24/m2 nH *neutral Hydrogen column density
40- 41 I2 h Rah Right Ascension 2000 (hours)
43- 44 I2 min Ram Right Ascension 2000 (minutes)
46- 49 F4.1 s Ras Right Ascension 2000 (seconds)
51 A1 - DE- Declination 2000 (sign)
53- 54 I2 deg DEd Declination 2000 (degrees)
56- 57 I2 arcmin DEm Declination 2000 (minutes)
59- 60 I2 arcsec DEs Declination 2000 (seconds)
62 I1 - nMask *Number of masked regions
64- 69 F6.2 arcmin X1 X position of masked region 1
71- 76 F6.2 arcmin Y1 Y position of masked region 1
78- 80 F3.1 arcmin R1 radius of masked region 1
82- 87 F6.2 arcmin X2 X position of masked region 2
89- 94 F6.2 arcmin Y2 Y position of masked region 2
96- 98 F3.1 arcmin R2 radius of masked region 2
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Note on Texp:
Refers to the exposure time of the observation after cleaning for
background flares and periods of bad aspect, as described in section 2.4.1
of J/MNRAS/341/1093.

Note on nH:
Values taken from the compilation of 1984ApJ...287..633M (Marshall &
Clark 1984).

Note on nMask:
Number of regions masked from the observation. If equal to 1 then the
X1, Y1, Y1 columns - and if equal to 2 the X2, Y2, R2 columns - list the
location and radius of the circle excluded from the survey. The coordinate
system has North and East the positive directions.

Byte-by-byte Description of file: extsrcs.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Southern SHARC catalogue name
17- 22 I6 --- ROR ROSAT observation request
24- 25 I2 h Rah Right Ascension 2000 (hours)
27- 28 I2 min Ram Right Ascension 2000 (minutes)
30- 33 F4.1 s Ras Right Ascension 2000 (seconds)
35 A1 - DE- Declination 2000 (sign)
37- 38 I2 deg DEd Declination 2000 (degrees)
40- 41 I2 arcmin DEm Declination 2000 (minutes)
43- 46 F4.1 arcsec DEs Declination 2000 (seconds)
48- 51 A4 - ID *ID code
53- 60 A8 - z *Source redshift
62-112 A51 - Notes *Matches with other catalogues
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Note on ID:
Indicates the source identification. The first letter - if it is one of L,
S, or I - refers to how the source was identified: L for from the
literature (the NASA Extragalactic Database); a S indicates the source was
spectroscopically identified; an I means that the identification was based
on the R-band image taken at the ESO 3.6m telescope; otherwise the
Digital Sky Survey image was used. The second letter lists which class of
object the source belongs to: a C means a cluster; a G a galaxy; a Q for
a QSO; an A for an AGN; and a S for a star. The letter P shows those
sources for which an optical point source lies close to, or at, the centre
of the X-ray emission; this source is taken to be the X-ray-emitting object.
The letter M refers to those cases where the extended X-ray emission is
actually from multiple point sources. A value of "-" means that the source
remains un-identified, and brackets around the ID show that the source
lies within 1 Mpc of the cluster identified in the Matches column.

Note on z:
The redshifts are obtained either from the literature or during the
optical follow-up phase of the survey. For clusters with an ID of SC,
the listed redshift is the average value of all the galaxies measured for
that cluster, where the number in brackets gives the number of such
galaxies.

Note on Notes:
Indicates other identifications for these sources (using a search radius
of 1 arcmin): the main catalogues referred to are 2000ApJS..126..209R for
BS and BSe (sources that are in Appendix~E only), 1998ApJ...502..558V for
[VMF98], 2000MNRAS.311..456M for RIXOS, 2002ApJS..140..265P for WARP,
1994IAUC.6100....1W for 1WGA, and the Abell catalogue (1989ApJS...70....1A).
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Byte-by-byte Description of file: numflux.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- n Number of clusters
4- 11 E8.2 10-14mW/m2 flux Total cluster flux (0.5-2.0 keV)
13- 20 E8.2 /deg2 Nflux *N(>flux) for Southern SHARC sample
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Note on Nflux:
Calculated assuming an Einstein-de Sitter cosmology with H_0 set to
50 km/s/Mpc and that the cluster core radius is 250 kpc at all redshifts.
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(End) Douglas Burke [Harvard-Smithsonian Center for Astrophysics] 09-Jun-2003