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Interpretation of the 115 day periodic modulation in the X-ray flux of NGC 5408 X-1

Interpretation of the 115 day periodic modulation in the X-ray flux of NGC 5408 X-1
Interpretation of the 115 day periodic modulation in the X-ray flux of NGC 5408 X-1
We comment on the recent observation of a 115-day modulation in the X-ray flux of the ultraluminous X-ray source (ULX) NGC 5408 X-1, and in particular, the interpretation of this modulation as the orbital period. We suggest that this modulation may instead be due to a precessing jet, and is thus superorbital in nature. Comparing the properties of this ULX with those of the prototypical microquasar SS 433, we argue that NGC 5408 X-1 is very similar to SS 433: a hyper-accreting stellar mass black hole in a shorter-period binary. If the analogy holds, the 115-day modulation is best explained by the still poorly-understood physics of inner-disc/jet precession and a longer observing baseline would be able to reveal an intrinsic phase jitter that is associated with such a precession.
accretion, accretion disks, black hole physics, galaxies individual (NGC 5408), X-rays binaries, X-rays individual (ULXs)
0004-637X
2480-2484
Foster, Deatrick
da461409-9dc8-4e2e-84a2-62bdcfed97c7
Charles, Phil
0429b380-0754-4dc1-8def-885c7fa6a086
Holley-Bockelmann, Kelly
86ff8c76-650d-476b-8a3b-0b318724fb98
Foster, Deatrick
da461409-9dc8-4e2e-84a2-62bdcfed97c7
Charles, Phil
0429b380-0754-4dc1-8def-885c7fa6a086
Holley-Bockelmann, Kelly
86ff8c76-650d-476b-8a3b-0b318724fb98

Foster, Deatrick, Charles, Phil and Holley-Bockelmann, Kelly (2010) Interpretation of the 115 day periodic modulation in the X-ray flux of NGC 5408 X-1. The Astrophysical Journal, 725 (2), 2480-2484. (doi:10.1088/0004-637X/725/2/2480).

Record type: Article

Abstract

We comment on the recent observation of a 115-day modulation in the X-ray flux of the ultraluminous X-ray source (ULX) NGC 5408 X-1, and in particular, the interpretation of this modulation as the orbital period. We suggest that this modulation may instead be due to a precessing jet, and is thus superorbital in nature. Comparing the properties of this ULX with those of the prototypical microquasar SS 433, we argue that NGC 5408 X-1 is very similar to SS 433: a hyper-accreting stellar mass black hole in a shorter-period binary. If the analogy holds, the 115-day modulation is best explained by the still poorly-understood physics of inner-disc/jet precession and a longer observing baseline would be able to reveal an intrinsic phase jitter that is associated with such a precession.

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More information

Published date: 2010
Additional Information: Imported from arXiv
Keywords: accretion, accretion disks, black hole physics, galaxies individual (NGC 5408), X-rays binaries, X-rays individual (ULXs)
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 339323
URI: http://eprints.soton.ac.uk/id/eprint/339323
ISSN: 0004-637X
PURE UUID: d93723ec-b456-43c0-8b7a-680493b0b65f

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Date deposited: 28 May 2012 14:37
Last modified: 14 Mar 2024 11:13

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Contributors

Author: Deatrick Foster
Author: Phil Charles
Author: Kelly Holley-Bockelmann

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