EDP Sciences
Special letters issue on: first science with integral
Free access
Issue
A&A
Volume 411, Number 1, November III 2003
Special letters issue on: first science with integral
Page(s) L415 - L419
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20031444


A&A 411, L415-L419 (2003)
DOI: 10.1051/0004-6361:20031444

Letter

First INTEGRAL observations of GRS 1915+105

D. C. Hannikainen1, O. Vilhu1, 2, J. Rodriguez3, 2, S. Brandt4, N. J. Westergaard4, N. Lund4, I. Mocoeur3, Ph. Durouchoux3, T. Belloni5, A. Castro-Tirado6, P. A. Charles7, A. J. Dean7, R. P. Fender8, M. Feroci9, P. Hakala1, R. W. Hunstead10, C. R. Kaiser7, A. King11, I. F. Mirabel3, G. G. Pooley12, J. Poutanen13, K. Wu14 and A. A. Zdziarski15

1  Observatory, PO Box 14, 00014, University of Helsinki, Finland
2  INTEGRAL Science Data Center, Chemin d'Écogia 16, 1290 Versoix, Switzerland
3  Centre d'Études de Saclay, DAPNIA/Service d'Astrophysique (CNRS FRE 2591), Bât. 709, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France
4  Danish Space Research Institute, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark
5  INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, 23807 Merate (LC), Italy
6  Instituto de Astrofísica de Andalucía (IAA-CSIC), PO Box 03004, 18080 Granada, Spain
7  Dept. of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
8  Astronomical Institute, "Anton Pannekoek", University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
9  Istituto Astrofisica Spaziale e Fisica Cosmica, Sezione di Roma, CNR, via Fosso del Cavaliere, 00133 Roma, Italy
10  School of Physics, University of Sydney, NSW 2006, Australia
11  Theoretical Astrophysics Group, University of Leicester, Leicester LE1 7RH, UK
12  Astrophysics Group, Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 0HE, UK
13  Astronomy Division, PO Box 3000, 90014 University of Oulu, Finland
14  MSSL, University College London, Holmbury St. Mary, Surrey RH5 6NT, UK
15  Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716 Warszawa, Poland

(Received 7 July 2003 / Accepted 16 September 2003)

Abstract
We present data from the first of six monitoring Open Time observations of GRS 1915+105 undertaken with the orbiting INTEGRAL satellite. The source was clearly detected with all three X-ray and gamma-ray instruments on board. GRS 1915+105 was in a highly variable state, as demonstrated by the JEM X-2 and ISGRI lightcurves. These and simultaneous RXTE/PCA lightcurves point to a novel type of variability pattern in the source. In addition, we fit the combined JEM X-2 and ISGRI spectrum between 3-300 keV with a disk blackbody + powerlaw model leading to typical parameter values found earlier at similar luminosity levels. A new transient, IGR J19140+098, was discovered during the present observation.


Key words: X-rays: binaries -- X-rays: GRS 1915+105

Offprint request: D. Hannikainen, diana@astro.helsinki.fi

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