ASAS-SN Confirmation of the Bright Microlensing Event TCP J05074264+2447555
ATel #10923; T. Jayasinghe (OSU), Subo Dong (KIAA-PKU), K. Z. Stanek, C. S. Kochanek, T. A. Thompson (OSU), J. L. Prieto (Diego Portales; MAS), B. J. Shappee (Univ. of Hawaii), T. W.-S. Holoien (Carnegie)
on 2 Nov 2017; 18:57 UT
Credential Certification: Krzysztof Stanek (stanek.32@osu.edu)
Subjects: Optical, Microlensing Event
The transient
TCP J05074264+2447555 was first discovered by T. Kojima on UT
2017-10-25.688. The
ASAS-SN Sky Patrol light curve (Shappee et al. 2014; Kochanek et
al. 2017) and follow-up spectroscopy (ATel #10919)
suggested this to be a probable microlensing event. The ASAS-SN light
curve for TCP J05074264+2447555 showed no evidence of intrinsic
variability. Swift observations (ATel #10921) found no X-ray source at
the position of this transient, but reported brightening in the UV
similar to the brightening observed in the optical, which is expected
for a microlensing event.
The source TCP J05074264+2447555 was first observed by ASAS-SN on UT
2014-12-16.399. The latest ASAS-SN photometry on UT 2017-11-02.411 suggests that
TCP J05074264+2447555 is fading, as was predicted by microlensing
models. The ASAS-SN light curve is well fit by
a single-lens microlensing model with a peak magnitude of V~11.5,
time of closest approach t_0=2458058.80 +/- 0.03 days (HJD), impact
parameter u_0=0.091 +/- 0.005 and Einstein crossing time t_E = 26.7
+/- 1.2 days for a peak magnification of 11. This best-fit model is
consistent with no blending.
We thank Las Cumbres Observatory and its staff for their continued
support of ASAS-SN. ASAS-SN is funded in part by the Gordon and Betty
Moore Foundation through grant GBMF5490 to the Ohio State University,
NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, the
Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, and the
Chinese Academy of Sciences South America Center for Astronomy
(CASSACA).
