Open AccessThai national telescope studies of ultraluminous X-ray sources
Author(s) -
K. Thongpoyai,
W. Luangtip,
U. Sawangwit,
T. P. Roberts,
S. Komonjinda,
V. Dhillon,
T. R. Marsh
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1380/1/012089
Subject(s) - physics , luminosity , astrophysics , telescope , x ray , astronomy , galaxy , optics
Ultraluminous X-ray sources (ULXs) are extra-galactic, non-nuclear sources with X-ray luminosity in excess of 10 39 erg s –1 . It has been thought that the majority of ULX populations are stellar-mass objects accreting matter at a super-Eddington rate. Although ULX studies are often focused in the X-ray regime, this work studied the ULXs in the optical regime, identified as the ULX counterparts (CTPs). The optical variability of nine CTPs were observed using the 2.4-m Thai National Telescope. Out of the nine ULXs, we detected three ULXs exhibiting strong variability up to ∼1 magnitude, suggesting that the CTP light does not come from the donor star’s emission. The paper discusses the physical origins of the variability which potentially explain the observed light curves.