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J/ApJ/405/94        Far-infrared emission from 5 galaxy clusters (Wise+ 1993)

Far-infrared emission from the intracluster medium. Wise M.W., O'Connell R.W., Bregman J.N., Roberts M.S. <Astrophys. J. 405, 94 (1993)> =1993ApJ...405...94W
ADC_Keywords: Clusters, galaxy ; Infrared sources ; Spectra, infrared Keywords: galaxies: clustering - infrared: galaxies - intergalactic medium Abstract: We have analyzed IRAS image data using a random position, multiple-aperture photometry method to study diffuse far-infrared emission for a sample of 56 clusters of galaxies at 60 and 100um. Five of the clusters in the sample exhibit excess far-infrared emission, but at low levels of significance. For A496 (Perseus) and MKW 1, this emission appears to be associated with a strong point source: in A2344, the observed excess is probably due to a foreground cirrus cloud. Two clusters, A262 and A2670, show evidence for extended diffuse emission. This emission is unlikely to be due to point sources associated with the clusters. In these two clusters, the diffuse emission shows evidence of being extended along the cluster's major axis. Far-infrared maps at 60 and 100um are presented for these five clusters. We find that contamination due to diffuse Galactic cirrus represents the major source of uncertainty in the measurement of far-infrared emission. The mean cluster fluxes for the sample as a whole are 44 and 107mJy for a 4' diameter aperture at 60 and 100um, respectively. The corresponding fluxes for a 10' diameter aperture are 138 and 253mJy at 60 and 100um. Photometry for the entire sample shows statistical evidence for excess emission at 60um associated with clusters in apertures 4' and 10' in diameter. This result is unlikely to be caused by random sampling errors. The flux distributions are analyzed for evidence that excess far-infrared radiation correlates with cluster environmental characteristics. Although we find evidence that poorer X-ray clusters are stronger far-infrared emitters, this result is tentative owing to the small sample sizes involved. The far-infrared luminosities, dust temperatures, and dust masses which these results imply are also presented. Finally, the origin and possible heating mechanism for dust in the intracluster medium is discussed. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table3.dat 65 238 Extracted point sources
See also: II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986) II/156 : IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989) Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 5 A5 --- Cluster Cluster name 7- 8 I2 h RAh Right ascension (1950) 10- 11 I2 min RAm Right ascension (1950) 13- 14 I2 s RAs Right ascension (1950) 16 A1 --- DE- Declination sign 17- 18 I2 deg DEd Declination (1950) 20- 21 I2 arcmin DEm Declination (1950) 23- 24 I2 arcsec DEs Declination (1950) 26- 35 A10 --- PSC Point Source designation, generally not in IRAS-PSC (Cat. II/125) 37- 41 F5.2 Jy F60umExt ? Extracted point source 60um flux 43- 47 F5.2 Jy F60umPSC IRAS-PSC or FSS (Cat. II/156) 60um flux 49- 53 F5.2 Jy F100umExt ? Extracted point source 100um flux 55- 59 F5.2 Jy F100umPSC IRAS-PSC or FSS 100um flux 61- 64 F4.2 --- r/rA Radius in Abell radius
History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 26-Feb-1998
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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