Optical observations of the x‐ray nova J0422+32

Abstract

We present the results of a photometric and spectroscopic study of the optical counterpart of the x‐ray nova J0422+32, a recently discovered black hole candidate. Its light curve shows a similar decay pattern to that of other novae black hole candidates, but with a slower decay rate. Its rapid decline started 240 days after the outburst. Its current magnitude is R∼19.4, which is still brighter than its quiescent value. Intensive photometry in January 1993 shows evidence of the 5.1 hour modulation reported by other groups. However, this modulation is not present in data taken in October 1992 and October 1993. Outburst spectra of J0422+32 are remarkably similar to those of Nova Muscae 1991 (a strong black‐hole candidate) including double peaked emission lines of Hα, Hβ, Hγ, He ii 4686 A, He i 5876 A and 6678 A.