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          Institute: MPI für Radioastronomie     Collection: Publikationen des MPI für Radioastronomie     Display Documents

ID: 125405.0, MPI für Radioastronomie / Publikationen des MPI für Radioastronomie
Exploring the role of jets in the radio/X-ray correlations of GX 339-4
Authors:Markoff, S.; Nowak, M.; Corbel, S.; Fender, R.; Falcke, H.
Date of Publication (YYYY-MM-DD):2003-01
Title of Journal:Astronomy & Astrophysics
Journal Abbrev.:Astron. Astrophys.
Issue / Number:2
Start Page:645
End Page:658
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:The Galactic black hole candidate X-ray binary GX 339-4 spends most of its time in the low/hard state, making it an ideal candidate for modeling the assumedly low accretion phase. The radio emission correlates very tightly with the X-rays over more than two orders of magnitude in X-ray flux density, suggesting that the jet plasma also plays a role at the higher frequencies. We compare the predictions of our jet model, with and without acceleration, to thirteen broadband simultaneous or quasi-simultaneous spectra over this changing flux history. In addition, we consider a simple standard thin disk which transitions to an optically thin accretion flow, in order to account for the assumedly thermal optical data seen in some observations. A solution without acceleration cannot describe the data without unrealistic energy requirements, nor explain the non-thermal radio spectrum seen during recent radio outbursts. But because of the low disk luminosity, and possibly the assumed disk geometry, acceleration in the jet is limited only by synchrotron cooling and can extend easily into the X-rays. We present a model which can account for all the broadband spectra included here, by changing only two parameters in the jet model: the input power and the location of the first acceleration zone. However, the model is most sensitive to changes in the jet power, the varying of which can also account for the slope of the observed radio/X-ray correlation analytically. At the highest low/hard state luminosities, the synchrotron self-Compton emission from the jet could be detectable with missions such as GLAST, providing a way to test the extent of the synchrotron contribution. We conclude that jet synchrotron is a possible way to explain the broadband features and this correlation, and discuss ways of incorporating this component into the "standard" corona picture.
Free Keywords:X-rays : binaries, X-rays : individual : GX 339-4, radiation mechanisms : non-thermal, stars : winds, outflows, black hole physics, accretion, accretion disks
Comment of the Author/Creator:Date: 2003, JAN
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Radioastronomie
External Affiliations:MIT, Ctr Space Res, Cambridge, MA 02139 USA.; Max Planck Inst Radioastron, D-53121 Bonn, Germany.; Ctr Etud Saclay, CEA, F-91191 Gif Sur Yvette, France.; Univ Paris 07, F-91191 Gif Sur Yvette, France.; Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands.; Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands.
Identifiers:ISI:000179896800025 [ID No:1]
ISSN:0004-6361 [ID No:2]
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