HEAO 1 scanning modulation collimator discovery of an extended X-ray source at Cygnus A

1979 ◽  
Vol 230 ◽  
pp. L67 ◽  
Author(s):  
G. Fabbiano ◽  
D. A. Schwartz ◽  
J. Schwarz ◽  
R. E. Doxsey ◽  
M. Johnston
Keyword(s):  
X Ray ◽  
Cygnus A ◽  
Author(s):  
M. Balucinska-Church ◽  
M. Ostrowski ◽  
L. Stawarz ◽  
M. J. Church
Keyword(s):  
X Ray ◽  

2012 ◽  
Vol 545 ◽  
pp. L3 ◽  
Author(s):  
Gayoung Chon ◽  
Hans Böhringer ◽  
Martin Krause ◽  
Joachim Trümper
Keyword(s):  
X Ray ◽  

Author(s):  
D. E. Harris ◽  
R. A. Perley ◽  
C. L. Carilli
Keyword(s):  
X Ray ◽  

1980 ◽  
Vol 85 ◽  
pp. 1062 ◽  
Author(s):  
C. A. Reid ◽  
M. D. Johnston ◽  
H. V. Bradt ◽  
R. E. Doxsey ◽  
R. E. Griffiths ◽  
...  
Keyword(s):  
X Ray ◽  

1989 ◽  
Vol 345 ◽  
pp. 140 ◽  
Author(s):  
R. A. Remillard ◽  
I. R. Tuohy ◽  
R. J. V. Brissenden ◽  
D. A. H. Buckley ◽  
D. A. Schwartz ◽  
...  

1979 ◽  
Vol 231 ◽  
pp. L105 ◽  
Author(s):  
J. Schwarz ◽  
U. Briel ◽  
G. Fabbiano ◽  
R. E. Griffiths ◽  
D. A. Schwartz ◽  
...  

1994 ◽  
Vol 431 ◽  
pp. L1 ◽  
Author(s):  
Shiro Ueno ◽  
Katsuji Koyama ◽  
Minoru Nishida ◽  
Shigeo Yamauchi ◽  
Martin J. Ward
Keyword(s):  
X Ray ◽  

1984 ◽  
Vol 108 ◽  
pp. 241-242
Author(s):  
A. P. Cowley ◽  
D. Crampton ◽  
J. B. Hutchings ◽  
R. Remillard

The best X-ray position (Einstein Observatory HRI - Giacconi et al 1979) for LMC X-3 confirms its identification with the early type star first suggested by Warren and Penfold (1975). Our spectroscopic observations obtained with the CTIO 4–m telescope show the WP star is a slightly reddened B3 V star with mV ≈ 16.9. Large radial velocity variations (Δv ≈ 500 km s−1) reveal an orbital period of 1.7049 days. From the orbital elements (Table 1) one can determine the mass function f(M) = (Mx sin i)3/(Mopt + Mx)2 = 2.3 M⊙, which shows without any assumptions about the mass of the optical star, the orbital inclination, or the mass ratio the unseen X-ray object has a mass >2.3 M⊙. Detailed analysis of the HEAO–1 scanning modulation collimator X-ray data shows that the system does not eclipse, implying that the orbital inclination is ≤ 65°. Assuming the B star mass lies between 4 and 8 M⊙ (an average mass for a normal B3 V star would be about 6–7 M⊙), the mass of the unseen companion must lie between 7 and 13 M⊙ (see Fig. 4a - Hutchings, this volume). Smaller inclinations of course give even higher masses. An important point is that the unseen star must have a mass larger than that of the B star, and thus if it were any kind of normal star it should be easily seen in the spectrum. Thus the X-ray emitting object is a very good candidate for a black hole.


1989 ◽  
Vol 134 ◽  
pp. 199-200
Author(s):  
R. J. V. Brissenden ◽  
I. R. Tuohy ◽  
G. V. Bicknell ◽  
R. A. Remillard ◽  
D. A. Schwartz

A sample of Active Galactic Nuclei (AGN) have been discovered during a program to identify the optical counterparts of X-ray sources detected by the Modulation Collimator experiment of the High Energy Astronomy Observatory-1 (HEAO-1). UV-excess techniques were used to identify the X-ray sources (Remillard et al. 1986) and the details of the identifications are given elsewhere (Remillard et al. 1988, Brissenden et al. 1988). We report here the preliminary results of a multi-wavelength study of these new AGN.


Nature ◽  
1978 ◽  
Vol 275 (5680) ◽  
pp. 517-518
Author(s):  
D. A. SCHWARTZ ◽  
H. GURSKY ◽  
J. SCHWARZ ◽  
H. BRADT ◽  
R. DOXSEY
Keyword(s):  
X Ray ◽  

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