Letter to the Editor

INTEGRAL observation of V 0332+53 in outburst

¹ Institut für Astronomie und Astrophysik – Astronomie, Sand 1, 72076 Tübingen, Germany
² INTEGRAL Science Data Centre, 16 Ch. d'Écogia, 1290 Versoix, Switzerland e-mail: Ingo.Kreykenbohm@obs.unige.ch
³ Observatoire de Genève, Chemin des Maillettes 51, 1290 Sauverny, Switzerland
⁴ N. Copernicus Astronomical Center, Bartycka 18, Warsaw 00-716, Poland
⁵ Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA, 94702-7450, USA

Received: 18 January 2005
Accepted: 9 February 2005

Abstract

We present the analysis of a 100 ks INTEGRAL (3-100 ) observation of the transient X-ray pulsar V 0332in outburst. The source is pulsating at  s with a clear double pulse from 6 to 60 . The average flux was ~550 mCrab between 20 and 60 . We modeled the broad band continuum from 5 to 100 with a power-law modified by an exponential cut off. We observe three cyclotron lines: the fundamental line at 24.9 , the first harmonic at 50.5 as well as the second harmonic at 71.7 , thus confirming the discovery of the harmonic lines by Coburn et al. (2005) in RXTEdata.