Item


One-sided jet at milliarcsecond scales in LS I +61˚ 303

We present Very Long Baseline Interferometry (VLBI) observations of the high mass X-ray binary LS I +61˚303, carried out with the European VLBI Network (EVN). Over the 11 hour observing run, performed ~10 days after a radio outburst, the radio source showed a constant flux density, which allowed sensitive imaging of the emission distribution. The structure in the map shows a clear extension to the southeast. Comparing our data with previous VLBI observations we interpret the extension as a collimated radio jet as found in several other X-ray binaries. Assuming that the structure is the result of an expansion that started at the onset of the outburst, we derive an apparent expansion velocity of 0:003 c, which, in the context of Doppler boosting, corresponds to an intrinsic velocity of at least 0:4 c for an ejection close to the line of sight. From the apparent velocity in all available epochs we are able to establish variations in the ejection angle which imply a precessing accretion disk. Finally we point out that LS I +61˚303, like SS 433 and Cygnus X-1, shows evidence for an emission region almost orthogonal to the relativistic jet

© Astronomy and Astrophysics, 2001, vol. 376, núm. 1, p. 217-223

EDP Sciences

Author: Massi, Maria
Ribó i Panosa, Marc
Peracaula i Bosch, Marta
Paredes i Poy, Josep Maria
Estalella i Boadella, Robert
Date: 2001
Abstract: We present Very Long Baseline Interferometry (VLBI) observations of the high mass X-ray binary LS I +61˚303, carried out with the European VLBI Network (EVN). Over the 11 hour observing run, performed ~10 days after a radio outburst, the radio source showed a constant flux density, which allowed sensitive imaging of the emission distribution. The structure in the map shows a clear extension to the southeast. Comparing our data with previous VLBI observations we interpret the extension as a collimated radio jet as found in several other X-ray binaries. Assuming that the structure is the result of an expansion that started at the onset of the outburst, we derive an apparent expansion velocity of 0:003 c, which, in the context of Doppler boosting, corresponds to an intrinsic velocity of at least 0:4 c for an ejection close to the line of sight. From the apparent velocity in all available epochs we are able to establish variations in the ejection angle which imply a precessing accretion disk. Finally we point out that LS I +61˚303, like SS 433 and Cygnus X-1, shows evidence for an emission region almost orthogonal to the relativistic jet
Format: application/pdf
Citation: Massi, M., Ribó, M., Paredes, J.M., Peracaula, M., i Estalella, R. (2001). One-sided jet at milliarcsecond scales in LS I +61˚303. Astronomy and Astrophysics, 376 (1), 217-223. Recuperat 30 abril de 2010, a http://dx.doi.org/10.1051/0004-6361:20010953
ISSN: 0004-6361 (versió paper)
1432-0746 (versió electrònica)
Document access: http://hdl.handle.net/10256/2148
Language: eng
Publisher: EDP Sciences
Collection: Reproducció digital del document publicat a: http://dx.doi.org/10.1051/0004-6361:20010953
Articles publicats (D-ATC)
Is part of: © Astronomy and Astrophysics, 2001, vol. 376, núm. 1, p. 217-223
Rights: Tots els drets reservats
Subject: Estels
Estels binaris de raigs X
Stars
X-rays double stars
Title: One-sided jet at milliarcsecond scales in LS I +61˚ 303
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

Subjects

Authors