Further follow-up of AT2018cow/ATLAS18qqn at Weihai Observatory
ATel #11758; C. Wu (NAOC), S. Hu (Shandong Univ), S. Antier (LAL), M. Boer (Artemis), X. Chen (Shandong Univ), N. Christensen (Artemis), B. Cordier (CEA), M. Coughlin (Caltech), D. Coward (UWA), B. Gendre (UWA), X. Han (NAOC), J. Wang (NAOC), A. Klotz (IRAP), N. Leroy (LAL), J. Mao (YNAO), K. Noysena (Artemis), D. Turpin (NAOC), J. Y. Wei (NAOC), H. Yin (Shandong Univ), W. Zheng (UC Berkeley) for the Hu and GRANDMA teams
on 22 Jun 2018; 09:38 UT
Credential Certification: Sarah Antier (antier@lal.in2p3.fr)
Subjects: Optical, Gamma-Ray Burst, Supernovae, Transient
We observed the field of ATLAS18qqn/AT2018cow (Smartt et al. ATel #11727) consecutively in Bessel filters BVRI with the 1-m telescope at the Weihai observatory. Observations started on 2018-06-20 12:23 UT for approximately 5 hours. We measured preliminary Vega magnitudes (not corrected for host galaxy background contamination) as follows:
B = 14.57 +/- 0.05 mag (start), k= 0.32 mag/day ;
V = 14.30 +/- 0.02 mag (start), k= 0.28 mag/day ;
R = 14.35 +/- 0.02 mag (start), k= 0.14 mag/day ;
I = 14.57 +/- 0.03 mag (start), k=-0.19 mag/day ;
where k is the decaying slope from linear fit. The fading is consistent with our previous observations (Zheng et al., ATel #11743) and other photometric reports : Ahumada et al. (ATel #11752), Im et al. (ATel #11750), Watson et al. (ATel #11751), Smart et al. (ATel #11742, #11727), Fremling et al. (ATel #11738), Chen et al. (ATel #11734, #11729).
We acknowledge great help of Weihai Observatory in obtaining these data .