GRS 1915+105

GRS 1915+105 or V1487 Aquilae is an X-ray binary star system which features a regular star and a black hole. It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat.[4] "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" reflects the approximate declination (10 degrees and 56 arcminutes). The near-infrared counterpart was confirmed by spectroscopic observations.[5] The binary system lies 11,000 parsecs away[6] in Aquila. GRS 1915+105 is the heaviest of the stellar black holes so far known in the Milky Way Galaxy,[7] with 10 to 18 times the mass of the Sun.[8] It is also a microquasar, and it appears that the black hole rotates at close to 1,150 times per second, with a spin parameter value between 0.82 and 1.00 (maximum possible value).[9]

GRS 1915+105
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquila
Right ascension 19h 15m 11.6s[1]
Declination +10° 56′ 44″[1]
Characteristics
Evolutionary stage Microquasar[2]
Spectral type KIII[3]
Astrometry
Parallax (π)0.120 ± 0.009[2] mas
Distance8,600+2,000
−1,600[2] pc
Details
Black hole
Mass12.4+2.0
−1.8[2] M☉
Other designations
V1487 Aquilae, Granat 1915+105, Nova Aquilae 1992, Granat 1915+10, INTEGRAL1 112
Database references
SIMBADdata

Galactic superluminal source
A sequence of MERLIN observation of the X-ray binary GRS 1915+105 taken over a few days.

In 1994, GRS 1915+105 became the first known galactic source that ejects material with apparent faster-than-light or superluminal velocities.[10]

Observations with high resolution radio telescopes such as VLA, MERLIN, and VLBI show a bi-polar outflow of charged particles, which emit synchrotron radiation at radio frequencies. These studies have shown that the apparent superluminal motion is due to a relativistic effect known as relativistic aberration, where the intrinsic velocity of ejecta is actually about 90% the speed of light.[6]

Growth regulation

Repeat observations by the Chandra X-Ray Observatory over the period of a decade have revealed what may be a mechanism for self-regulation of the rate of growth of GRS 1915+105. The jet of materials being ejected is occasionally choked off by a hot wind blowing off the accretion disk. The wind deprives the jet of materials needed to sustain it. When the wind dies down, the jet returns.[11]

References
  1. Liu, Q. Z; Van Paradijs, J; Van Den Heuvel, E. P. J (2007). "A catalogue of low-mass X-ray binaries in the Galaxy, LMC, and SMC (Fourth edition)". Astronomy and Astrophysics. 469 (2): 807. arXiv:0707.0544. Bibcode:2007A&A...469..807L. doi:10.1051/0004-6361:20077303. S2CID 14673570.
  2. Reid, M. J; McClintock, J. E; Steiner, J. F; Steeghs, D; Remillard, R. A; Dhawan, V; Narayan, R (2014). "A Parallax Distance to the Microquasar GRS 1915+105 and a Revised Estimate of its Black Hole Mass". The Astrophysical Journal. 796 (1): 2. arXiv:1409.2453. Bibcode:2014ApJ...796....2R. doi:10.1088/0004-637X/796/1/2. S2CID 9800558.
  3. Abubekerov, M. K; Antokhina, E. A; Cherepashchuk, A. M; Shimanskii, V. V (2006). "The mass of the compact object in the low-mass X-ray binary 2S 0921-630". Astronomy Reports. 50 (7): 544. arXiv:1201.4689. Bibcode:2006ARep...50..544A. doi:10.1134/S1063772906070043. S2CID 40984265.
  4. Castro-Tirado, A. J; Brandt, S; Lund, N (1992). "Grs 1915+105". IAU Circ. 5590: 2. Bibcode:1992IAUC.5590....2C.
  5. Castro-Tirado, A. J; Geballe, T. R; Lund, N (1996). "Infrared Spectroscopy of the Superluminal Galactic Source GRS 1915+105 During the September 1994 Outburst". Astrophysical Journal Letters. 461 (2): L99. Bibcode:1996ApJ...461L..99C. doi:10.1086/310009.
  6. Fender, R. P; Garrington, S. T; McKay, D. J; Muxlow, T. W. B; Pooley, G. G; Spencer, R. E; Stirling, A. M; Waltman, E. B (1999). "MERLIN observations of relativistic ejections from GRS 1915+105". Monthly Notices of the Royal Astronomical Society. 304 (4): 865. arXiv:astro-ph/9812150. Bibcode:1999MNRAS.304..865F. doi:10.1046/j.1365-8711.1999.02364.x. S2CID 144364.
  7. "A Very Massive Stellar Black Hole in the Milky Way Galaxy". Retrieved 2017-11-25.
  8. Greiner, J. (2001). "GRS 1915+105". arXiv:astro-ph/0111540.
  9. Jeanna Bryne. "Pushing the Limit: Black Hole Spins at Phenomenal Rate". space.com. Retrieved 2017-11-25.
  10. Mirabel, I. F; Rodríguez, L. F (1994). "A superluminal source in the Galaxy". Nature. 371 (6492): 46. Bibcode:1994Natur.371...46M. doi:10.1038/371046a0. S2CID 4347263.
  11. "An Erratic Black Hole Regulates Itself" (Press release). NASA. 2009-03-25. Retrieved 2009-04-16.

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