Swift J105330.1+164710, a new X-ray transient in NGC 3447
ATel #16301; P. A. Evans, K. L. Page, S. Srivastava (U. Leicester), S. Campana, B. Sbarufatti ( INAF/OAB), D. B. Malesani (DAWN/NBI and Radboud Univ)
on 20 Oct 2023; 12:33 UT
Credential Certification: Phil Evans (pae9@star.le.ac.uk)
Subjects: X-ray, Transient
Swift-XRT has detected a new transient, Swift J105330.1+164710, in a 2.3 ks
observation beginning at 2023-10-19 12:23:09 UT. The transient is located at:
RA, Dec = 163.3757, 16.7864 degrees which is equivalent to:
RA (J2000): 10h 53m 30.17s
Dec(J2000): +16d 47m 10.9s
with an uncertainty of 5.4" (radius, 90% confidence).
The source count-rate is 1.6 (+0.7, -0.5) x 10^-2 ct s^-1, whereas the
historical upper limit from earlier XRT observations is 3.8 x 10^-4 ct/sec (all
values over 0.3-10 keV).
We have only 13 X-ray photons, making spectral measurements highly uncertain, however
a power-law fit yields a 0.3-10 keV flux of 3.7 (+1.9, -2.0) x 10^-13 erg cm^-2 s^-1.
The X-ray position is consistent with the interacting galaxy pair NGC 3447, the
distance to which appears somewhat uncertain. Reiss et al. (2016, ApJ 826, 56)
give a distance of 24.1 Mpc based on Cepheid relationships, whereas the galaxy
is in the LGG225 group with a distance of ~15 Mpc (Marino et al. 2010, A&A, 511,
29). Assuming the new transient is within NGC 3447, this gives an X-ray
luminosity in the range 1.0 -- 2.5 x 10^40 erg s^-1.
Follow-up observations are strongly encouraged.
This transient was discovered by the real-time transient detector within LSXPS,
details of the source can be seen at https://www.swift.ac.uk/LSXPS/transients/3202.
The LSXPS transient page for Swift J105330.1+164710.
