Does GRS 1915+105 exhibit “canonical” black-hole states?

¹ G.A.C.E, Instituto de Ciencias de los Materiales, University of Valencia, PO Box 22085, 46071 Paterna, Valencia, Spain
² Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
³ Astronomical Institute “Anton Pannekoek”, University of Amsterdam and Center for High-Energy Astrophysics, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands

Corresponding author: P. Reig, pablo.reig@uv.es

Received: 15 May 2003
Accepted: 29 August 2003

Abstract

We have analysed RXTE data of the superluminal source GRS 1915+105 in order to investigate if, despite its extreme variability, it also exhibits the canonical source states that characterise other black-hole candidates. The phenomenology of GRS 1915+105 has been described in terms of three states (named A, B and C) based on their hardness ratios and position in the colour-colour diagram. We have investigated the connection between these states and the canonical behaviour and found that the shape of the power spectral continuum and the values of the best-fit model parameters to the noise components in all three states indicate that the source shows properties similar to the canonical very high state.