Optical upper-limit of the ULX candidate Swift J004327.6+410452
ATel #5771; M. Uemura, Y. Moritani, T. Ui (Hiroshima Univ.), P. Gandhi (Durham Univ.), and M. Middleton (Univ. Amsterdam)
on 16 Jan 2014; 13:19 UT
Credential Certification: Makoto Uemura (uemuram@hiroshima-u.ac.jp)
Subjects: Optical, Black Hole, Transient
We have obtained optical imaging of the field of the ULX candidate in M31 (ATEL #5743,#5752). The image was taken on 10:11:48(UT) on 13 Jan. 2014. We used the 1.5-m "Kanata" telescope of Hiroshima University. The exposure time was 300 sec. The seeing size was about 2.4". We removed the contamination of the nearby star 2MASS J00432709+4104521 by fitting PSF and subtracting it. As a result, no clear optical counterpart brighter than Rc=19.4 can be seen at the position of the X-ray source reported in ATEL #5752. Correcting for an Rc-band extinction of 2.1 mag (Schlafly & Finkbeiner 2011), this corresponds to a monochromatic luminosity upper-limit, nu*L(nu)<1x10^{38} erg/s at 5x10^{14} Hz. The optical images can be seen at: http://home.hiroshima-u.ac.jp/uemuram/J0043_M31/
