1996/02/22 by Claude Chevalier, C. Chevalier, Chevalier, Claude +3
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Mechanics and Biomechanics Studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9602114
10 pages, 6 figures. Paper and figures available at http://www.obs-hp.fr/www/preprints/pp93/pp93.html Astronomy and Astrophysics, in press
arxiv created 1996/02/22 · openalex publication_date 1996/02/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
CCD photometry of the black hole candidate GRO~J0422+32 in quiescence, obtained at Haute-Provence from 1994 November to 1995 February, reveals a double-wave modulation at a period close to the value we found during outbursts and also close to one of the possible periods derived by Filippenko, Matheson and Ho (1995) from spectroscopic observations with the W. M. Keck 10-m telescope. A period of 0.212140 ± 0.000003 d (5.09136 ± 0.00007 h) fits all our photometric data from 1993 January to 1995 February and yields a minimum in our light curves at the inferior conjunction of the M star, as determined from the radial velocity data of Filippenko et al. (1995). The quiescent Rc band light curve exhibits a changing asymmetry of shape and a variable amplitude. On two consecutive nights the source was found constant to within ± 0.05 mag, suggesting an upper limit on the ellipsoidal effect in this band.