KAIT optical observations of the X-ray outburst from XTE J1946+274

ATel #16720; WeiKang Zheng and Alexei V. Filippenko (UCB), SVOM JSWG: Jian-Yan Wei (NAOC, China), Bertrand Cordier (CEA, F), Shuang-Nan Zhang (IHEP, CN), Stephane Basa (LAM, F), Jean-Luc Attéia (IRAP, F), Arnaud Claret (CEA, F), Zi-Gao Dai (USTC, CN), Frederic Daigne (IAP, F), Jin-Song Deng (NAOC, CN), Andrea Goldwurm (APC, F), Diego Götz (CEA, F), Xu-Hui Han (NAOC, CN), Cyril Lachaud (APC, F), En-Wei Liang (GXU, CN), Yu-Lei Qiu (NAOC, CN), Susanna Vergani (Obs. Paris, F), Jing Wang (NAOC, CN), Chao Wu (NAOC, CN), Li-Ping Xin (NAOC, CN), Bing Zhang (UNLV, CN) report on behalf of the KAIT GRB team:
on 19 Jul 2024; 09:28 UT
Credential Certification: Weikang Zheng (zwk@astro.berkeley.edu)

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The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, responded to the SVOM triggers (Rodriguez et al, ATel #16719) on the X-ray outburst from XTE J1946+274, which was also detected by MAXI/GSC (Nakajima et al. ATel #16717). A set of 60s images were obtained in the clear (roughly R) filters with 3x3 tiling (each field of view of 6.7'x6.7'). The optical counterpart of XTE J1946+274 was well detected in one of the 3x3 tiling field. B,V,R and I band images were also obtained at later epochs. Our photometry show that the object is at similar magnitude as the archive magnitude (B=18.76, V=16.92, R=15.62, I=14.38) given in simbad, no obvious brightness changes was seen in all filters. Our photometry table is listed below:
Start UT MJD Mag Err Filter
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Jul 18 08:17:30 60509.3456 15.44 0.02 clear
Jul 18 08:22:16 60509.3489 15.44 0.02 clear
Jul 18 08:26:56 60509.3522 15.46 0.02 clear
Jul 18 08:32:34 60509.3562 15.44 0.01 clear
Jul 18 08:40:16 60509.3615 15.46 0.02 clear
Jul 18 08:48:01 60509.3669 15.43 0.01 clear
Jul 18 08:56:43 60509.3731 15.45 0.02 clear
Jul 18 09:07:22 60509.3805 15.46 0.02 clear
Jul 18 10:47:34 60509.4500 18.93 0.20 B
Jul 18 10:48:51 60509.4509 16.97 0.03 V
Jul 18 10:50:05 60509.4518 15.67 0.02 R
Jul 18 10:51:22 60509.4527 14.43 0.02 I
Jul 18 10:52:35 60509.4535 15.45 0.02 clear
Jul 18 10:57:17 60509.4568 18.80 0.17 B
Jul 18 10:58:34 60509.4577 16.97 0.03 V
Jul 18 10:59:47 60509.4585 15.68 0.01 R
Jul 18 11:01:05 60509.4594 14.42 0.01 I
Jul 18 11:02:20 60509.4603 15.43 0.02 clear
Jul 18 11:03:36 60509.4612 18.72 0.17 B
Jul 18 11:04:54 60509.4621 17.00 0.04 V
Jul 18 11:06:06 60509.4629 15.69 0.02 R
Jul 18 11:07:23 60509.4638 14.39 0.01 I
Jul 18 11:08:39 60509.4647 15.43 0.02 clear
Jul 18 11:09:54 60509.4656 18.58 0.12 B
Jul 18 11:11:12 60509.4665 16.95 0.03 V
Jul 18 11:12:26 60509.4673 15.65 0.02 R