Optical emission of the ultraluminous X-ray source NGC 5408 X-1: Donor star or irradiated accretion disk?

Fabien Grise, P. Kaaret, S. Corbel, H. Feng, D. Cseh, L. Tao

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

We obtained three epochs of simultaneous Hubble Space Telescope (HST)/Wide Field Camera 3 and Chandra observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1. The counterpart of the X-ray source is seen in all HST filters, from the UV through the near-IR (NIR), and for the first time, we resolve the optical nebula around the ULX. We identified a small OB association near the ULX that may be the birthplace of the system. The stellar association is young, 5 Myr, contains massive stars up to 40 M ̇, and is thus similar to associations seen near other ULXs, albeit younger. The UV/optical/NIR spectral energy distribution (SED) of the ULX counterpart is consistent with that of a B0I supergiant star. We are also able to fit the whole SED from the X-rays to the NIR with an irradiated disk model. The three epochs of data show only marginal variability and thus, we cannot firmly conclude on the nature of the optical emission.

Original languageEnglish (US)
Article number123
JournalAstrophysical Journal
Volume745
Issue number2
DOIs
StatePublished - Feb 1 2012

Fingerprint

accretion disks
light emission
accretion
stars
x rays
spectral energy distribution
Hubble Space Telescope
time measurement
supergiant stars
nebulae
massive stars
energy
cameras
filter
filters
young
distribution

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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title = "Optical emission of the ultraluminous X-ray source NGC 5408 X-1: Donor star or irradiated accretion disk?",
abstract = "We obtained three epochs of simultaneous Hubble Space Telescope (HST)/Wide Field Camera 3 and Chandra observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1. The counterpart of the X-ray source is seen in all HST filters, from the UV through the near-IR (NIR), and for the first time, we resolve the optical nebula around the ULX. We identified a small OB association near the ULX that may be the birthplace of the system. The stellar association is young, 5 Myr, contains massive stars up to 40 M ̇, and is thus similar to associations seen near other ULXs, albeit younger. The UV/optical/NIR spectral energy distribution (SED) of the ULX counterpart is consistent with that of a B0I supergiant star. We are also able to fit the whole SED from the X-rays to the NIR with an irradiated disk model. The three epochs of data show only marginal variability and thus, we cannot firmly conclude on the nature of the optical emission.",
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Optical emission of the ultraluminous X-ray source NGC 5408 X-1 : Donor star or irradiated accretion disk? / Grise, Fabien; Kaaret, P.; Corbel, S.; Feng, H.; Cseh, D.; Tao, L.

In: Astrophysical Journal, Vol. 745, No. 2, 123, 01.02.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optical emission of the ultraluminous X-ray source NGC 5408 X-1

T2 - Donor star or irradiated accretion disk?

AU - Grise, Fabien

AU - Kaaret, P.

AU - Corbel, S.

AU - Feng, H.

AU - Cseh, D.

AU - Tao, L.

PY - 2012/2/1

Y1 - 2012/2/1

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AB - We obtained three epochs of simultaneous Hubble Space Telescope (HST)/Wide Field Camera 3 and Chandra observations of the ultraluminous X-ray source (ULX) NGC 5408 X-1. The counterpart of the X-ray source is seen in all HST filters, from the UV through the near-IR (NIR), and for the first time, we resolve the optical nebula around the ULX. We identified a small OB association near the ULX that may be the birthplace of the system. The stellar association is young, 5 Myr, contains massive stars up to 40 M ̇, and is thus similar to associations seen near other ULXs, albeit younger. The UV/optical/NIR spectral energy distribution (SED) of the ULX counterpart is consistent with that of a B0I supergiant star. We are also able to fit the whole SED from the X-rays to the NIR with an irradiated disk model. The three epochs of data show only marginal variability and thus, we cannot firmly conclude on the nature of the optical emission.

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