THE RELATIVISTIC IRON LINE
OF GRS 1915+105


Poster presented at the
Secondo Congresso Nazionale Astrofisica degli Oggetti Compatti (CNOC),
Bologna, September 19-21, 2001
 
 
Andrea Martocchia (1), Giorgio Matt (1), Vladimir Karas (2), Tomaso Belloni (3), Marco Feroci (4).
 
1 - Dipartimento di Fisica, Universita' degli Studi "ROMA TRE"
Via della Vasca Navale 84, I--00146 Roma (Italy); E-mail: martocchia@fis.uniroma3.it, matt@fis.uniroma3.it

2 - Astronomical Institute of the Charles University, Faculty of Mathematics and Physics,
V Holesovickach 2, CZ--180 00 Praha (Czech Republic); E-mail: vladimir.karas@mff.cuni.cz

3 - Osservatorio Astronomico di Brera,
Via E. Bianchi 46, I--23807 Merate (Italy); E-mail: tmb@merate.mi.astro.it

4 - Istituto di Astrofisica Spaziale (IAS/CNR), Area di Ricerca di Tor Vergata,
Via Fosso del Cavaliere 100, I--00133 Roma (Italy); E-mail: feroci@ias.rm.cnr.it

Abstract


We studied the properties of the iron K alpha fluorescent line detected in the April 19, 1998 BeppoSAX spectrum of the "microquasar" GRS 1915+105. In this observation, the line emission was unusually intense. The feature is broad and skewed, and well fitted with a relativistic disc profile, although there is no evidence of emission very near to the innermost stable orbit, even in Schwarzschild metric.