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A deep x ray survey in the Lockman hole and the soft x ray log N - log SThe longest pointed observation (152 ksec) with the Rosat position sensitive proportional counter in the direction of the absolutely lowest neutral hydrogen column density is discussed. 26 shallower fields from the Rosat medium sensivity survey are analyzed. 1176 X-ray sources were detected in at least one Rosat energy band in these fields covering a total solid angle of 9.3 deg; 661 of these sources constitute a statistically complete sample detected in the hard band with 0.5 to 2 keV fluxes greater than 2.5 times 10 to the power of minus 15 erg/sq cm s. The faintest limiting flux of the survey is analyzed. Detailed simulations show that confusion effects and other selection biases are relatively small and can be corrected for in the sample. From an analysis in the Lockman field, a best fit slope of approximately 1.8 is found for the extrapolation of the differential X-ray counts below 2.5 times 10 to the power of minus 15 erg/sq cm s. On the basis of this analysis an upper limit of approximately 25% can be found for a truly diffuse background component in the Rosat hard band.
Document ID
19940015701
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Hasinger, G.
(Max-Planck-Inst. fuer Physik und Astrophysik Garching, Germany)
Burg, R.
(Johns Hopkins Univ. Baltimore, MD., United States)
Giacconi, R.
(Space Telescope Science Inst. Baltimore, MD., United States)
Hartner, G.
(Max-Planck-Inst. fuer Physik und Astrophysik Garching, Germany)
Schmidt, M.
(California Inst. of Tech. Pasadena., United States)
Truemper, J.
(Max-Planck-Inst. fuer Physik und Astrophysik Garching, Germany)
Zamorani, G.
(Osservatorio Astronomico Bologna, Italy)
Date Acquired
September 6, 2013
Publication Date
December 1, 1992
Subject Category
Astronomy
Report/Patent Number
MPE-PREPRINT-238
NAS 1.26:194698
NASA-CR-194698
Accession Number
94N20174
Funding Number(s)
CONTRACT_GRANT: ASI-91-RS-86
CONTRACT_GRANT: NAG8-794
CONTRACT_GRANT: NAGW-2508
CONTRACT_GRANT: NAG5-1531
CONTRACT_GRANT: NAG5-1649
Distribution Limits
Public
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