Please use this identifier to cite or link to this item:
|Title:||Radio detections of the neutron star X-ray binaries 4U 1820 - 30 and Ser X-1 in soft X-ray states|
Fender, R. P.
Jonker, P. G.
Van der Klis, M.
|Keywords:||Estels binaris de raigs X|
Estels de neutrons
Astronomia de raigs X
|Publisher:||Royal Astronomical Society|
|Abstract:||We present the analysis of simultaneous X-ray (RXTE) and radio (VLA) observations of two atoll-type neutron star X-ray binaries: 4U 1820 - 30 and Ser X-1. Both sources were steadily in the soft (`banana') X-ray state during the observations. We have detected the radio counterpart of 4U 1820 - 30 at 4.86 and 8.46 GHz at a flux density of ~0.1 mJy. This radio source is positionally coincident with the radio pulsar PSR 1820 - 30A. However, the radio emission of the pulsar falls rapidly with frequency (~ν-3), and we argue that the radio emission of the X-ray binary is dominant above ~2 GHz. Supporting this interpretation, comparison with previous observations reveals variability at the higher radio frequencies that is likely to be due to the X-ray binary. We have detected for the first time the radio counterpart of Ser X-1 at 8.46 GHz, also at a flux density of ~0.1 mJy. The position of the radio counterpart has allowed us to identify its optical counterpart unambiguously. We briefly discuss similarities and differences between the disc-jet coupling in neutron star and black hole X-ray binaries. In particular, we draw attention to the fact that, contrary to other states, neutron star X-ray binaries seem to be more radio-loud than persistent black hole candidates when the emission is `quenched' in the soft state.|
|Note:||Reproducció del document publicat a: http://dx.doi.org/10.1111/j.1365-2966.2004.07768.x|
|It is part of:||Monthly Notices of the Royal Astronomical Society, 2004, vol. 351, num. 1, p. 186-192|
|Appears in Collections:||Articles publicats en revistes (Física Quàntica i Astrofísica)|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.