A search for X-rays from the long-duration microlensing event MACHO-96-BLG-5

Yoshitomo Maeda, Aya Kubota, Yoshihito Kobayashi, Akiharu Itoh, Hideyo Kunieda, Yuichi Terashima, Yohko Tsuboi

研究成果: Article査読

8 被引用数 (Scopus)

抄録

MACHO-96-BLG-5 was a microlensing event of exceptionally long duration, lasting ∼800 days, which is suggestive of a stellar-mass black hole for the lens. With a 9.8 ks Chandra ACIS-S observation, we detected no X-ray events associated with the position of MACHO-96-BLG-5. An upper limit is estimated as 4.6 counts at the 99% confidence level. By assuming an absorbed power law spectrum with a photon index Γ = 1.4-2.0, the upper limit on the 0.3-8 keV luminosity is estimated as (7-8) × 1029 ergs s-1 at an assumed distance of 1 kpc. The corresponding Eddington ratio is (8-9) × 10-10 for a black hole of 6 M. The luminosity is lower than observed for quiescent black hole binaries in our Galaxy and is consistent with a scenario, previously suggested by Bennett et al., in which the lens for MACHO-96-BLG-5 is an isolated stellar-mass black hole, although other possibilities are not ruled out.

本文言語English
ページ(範囲)L65-L68
ジャーナルAstrophysical Journal
631
1 II
DOI
出版ステータスPublished - 2005 9 20
外部発表はい

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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