摘要:

AbstractTo mark the occasions of the 35th anniversary of the birth of X‐ray astronomy on June 18, 1962, and the 7th anniversary of the first light of ROSAT on June 16, 1990, the Astrophysikalisches Institut Potsdam (AIP) and the NASA Goddard Space Flight Center X‐ray Astrophysics Branch cosponsored a workshop entitled“X‐ray S

ISSN:0004-6337    

DOI:10.1002/asna.2123190102

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractThe Röntgensatellite ROSAT has been in orbit since June 1,1990. After a 6‐month all‐sky survey ˜ 6,500 pointed observations have been performed. In total more than 150,000 X‐ray sources have been detected. Among the various object classes observed are comets, stars, white dwarfs, cataclysmic variables, neutron stars, black hole candidates, supernova remnants, nearby galaxies, AGN, and clusters of galaxies. Many of these objects are known to be time variable sources. Various catalogues of sources found in the ROSAT All‐Sky Survey and in the pointed observations are used as the basis for studying the temporal behaviour of ROSAT sources. This paper deals with the description, production and content of the various ROSAT catalogues with particular emphasis on the usefulness for the study of source va

ISSN:0004-6337    

DOI:10.1002/asna.2123190103

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractWe describe how recent X‐ray surveys have led to advances in the understanding of ultrasoft narrow‐line Seyfert 1 galaxies. The number of known ultrasoft narrow‐line Seyfert 1s has increased greatly in recent years due to X‐ray surveys, and it is now possible to obtain high quality 0.1–10 keV spectral and variability measurements for a large number of these galaxies. We generalize some of the correlations between X‐ray properties and optical emission line properties, focusing on how theROSATband spectral slope appears to be directly connected to the Boroson&Green (1992) primary eigenvector. We discuss how ultrasoft narrow‐line Seyfert 1s may well have extremal values of a primary physical parameter, and we describe new projects that should further improve our understanding of these extreme representatives of Sey

ISSN:0004-6337    

DOI:10.1002/asna.2123190104

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractA brief review is given of the study of radio‐loud AGN from the ROSAT Survey. Some general results as well as specific questions occuring in correlations of two large data bases are discusse

ISSN:0004-6337    

DOI:10.1002/asna.2123190105

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractWe present the scientific goals and the strategy of the REX survey, a project which has been recently initiated at the Brera Astronomical Observatory in Milan with the aim of selecting a large and statistically representative sample of BL Lac objects and other kinds of Radio Loud Active Galactic Nuclei. More than 1200 PSPC images (for a total of about 2700 square deg. of sky) have been searched for sources detected also in the VLA NVSS survey (as of June 1977). The data and source selection criteria, the cross‐correlation technique and preliminary results are presented and discusse

ISSN:0004-6337    

DOI:10.1002/asna.2123190106

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractThe results of ROSAT deep surveys were well established during the first few years of ROSAT operation (Papers I ‐ XV in this collaboration, and other papers in this Volume). They have allowed us to measure the AGN Luminosity Function and its evolution in soft X‐rays, both for AGN of Type I and for objects classified as AGN Type II/Narrow‐Line X‐ray Galaxy (NXLG). More recently, we have performep surveys with ASCA of some of these same ROSAT fields. Based on coincidences with ROSAT deep survey sources, and further optical spectroscopic identification, we discuss the optical identification content of five of our ASCA deep survey fields. Perhaps not surprisingly, we have observed significant cosmological evolution for Type I AGN in the 2–10 keV energy range, with an evolutionary rate which is consistent with that measured in other passbands. The predicted contribution of Type I AGN to the 2–10 keV X‐ray background (XRB) is about 60%, and the combined contribution from AGN of Types I&II is consist

ISSN:0004-6337    

DOI:10.1002/asna.2123190107

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2123190108

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2123190109

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2123190110

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

ISSN:0004-6337    

DOI:10.1002/asna.2123190111

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY