Search for a narrow annihilation feature correlated with the MeV emission of Cygnus X-1

Journal Article · Tue Aug 01 04:00:00 EDT 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/185510· OSTI ID:5402723

Ling, J C; Wheaton, WM A ^[1]

---

1. California Institute of Technology, Pasadena (USA)

Strong gamma-ray emission near 1 MeV from Cygnus X-1 observed in the fall of 1979 during the 'gamma 1' period has been interpreted by Liang and Dermer (1988) as thermal emission from a relativistic, pair-dominated region surrounding the black hole. The observed gamma-rays should interact with each other and with X-rays to form electron/positron pairs inside and outside the accretion disk. Because the Eddington limit is reduced by a factor of 1836 in the presence of positrons, some pairs formed inside the disk may also escape the system under the influence of radiation pressure. If these pairs stop in the cold surrounding medium, a narrow 511 keV annihilation feature should be produced. The high resolution gamma 1 spectrum has been examined for such a feature, and some evidence at 1.9 sigma statistical significance for the line is observed with a flux which is generally consistent with theoretical expectations. 16 refs.

• OSTI ID: 5402723
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 343; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
ANNIHILATION
ASTRONOMY
BASIC INTERACTIONS
BINARY STARS
BLACK HOLES
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
EDDINGTON THEORY
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
GAMMA ASTRONOMY
GAMMA RADIATION
INTERACTIONS
IONIZING RADIATIONS
PAIR PRODUCTION
RADIATIONS
SPECTRA
STARS