Multiwavelength Approach to Gamma-Ray Sources in the Galactic Center Region
Abstract
The two strongest persistent soft gamma-ray sources in the Galactic center region 1E 1740.7-2942 and GRS 1758-258 appear at centimeter wavelengths as microquasar stellar remnants from which emanate double-sided radio jets that extend over a few parsecs. Millimeter observations of the dust emission and molecular transitions that trace high-density gas show that in the direction of the compact annihilation source 1E 1740.07-2942 there is a dense molecular cloud with a column density greater than or equal to 8 x 1022 cm-2 that may produce greater than or equal to 50 mg of optical absorption. On the contrary, along the direction to GRS 1758-258 there are only approximately 12 mag of optical absorption. Since at the position of the compact radio counterparts no optical or infrared sources have been found, the nature of these sources remains an open question. However, the limiting magnitudes imply that GRS 1758-258 cannot be a binary system with a companion star of spectral type earlier than A5 V. We review the known radio jets associated to other X-ray source which are located in other regions of the Galaxy and conclude that collimated jets of relativistic particules are frequently associated to accretion into collapsed objects of stellar mass.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- June 1994
- DOI:
- 10.1086/191980
- Bibcode:
- 1994ApJS...92..369M
- Keywords:
-
- Galactic Nuclei;
- Gamma Ray Astronomy;
- Interstellar Matter;
- Molecular Clouds;
- Radio Jets (Astronomy);
- X Ray Sources;
- Electromagnetic Absorption;
- Milky Way Galaxy;
- Positron Annihilation;
- Stellar Mass Accretion;
- Astronomy;
- GALAXY: CENTER;
- GAMMA RAYS: OBSERVATIONS;
- RADIO CONTINUUM: ISM;
- X-RAYS: ISM