eCite Digital Repository

The optical counterpart of SAX J1808.4-3658, the transient bursting millisecond X-ray pulsar


Giles, AB and Hill, KM and Greenhill, JG, The optical counterpart of SAX J1808.4-3658, the transient bursting millisecond X-ray pulsar, Monthly Notices of the Royal Astronomical Society, 304, (1) pp. 47-51. ISSN 0035-8711 (1999) [Refereed Article]

DOI: doi:10.1046/j.1365-8711.1999.02361.x


A set of CCD images have been obtained during the decline of the X-ray transient SAX J1808.4-3658 during 1998 April-June. The optical counterpart has been confirmed by several pieces of evidence. The optical flux shows a modulation on several nights that is consistent with the established X-ray binary orbit period of 2 h. This optical variability is roughly in antiphase with the weak X-ray modulation. The source mean magnitude of V-16.7 on April 18 declined rapidly after April 22. From May 2 onwards the magnitude was more constant at around V = 18.45 but by June 27 it was below our sensitivity limit. The optical decline precedes the rapid second phase of the X-ray decrease by 3 ± 1 d. The source has been identified on a 1974 UK Schmidt plate at an estimated magnitude of ∼20. The nature of the optical companion is discussed.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Giles, AB (Dr Barry Giles)
UTAS Author:Hill, KM (Dr Kym Hill)
UTAS Author:Greenhill, JG (Dr John Greenhill)
ID Code:16429
Year Published:1999
Web of Science® Times Cited:36
Deposited By:Physics
Deposited On:1999-08-01
Last Modified:2000-05-20

Repository Staff Only: item control page