TITLE: GCN CIRCULAR NUMBER: 33255 SUBJECT: ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations DATE: 23/02/03 15:40:58 GMT FROM: Ting-Wan Chen at MPE S. Yang (Stockholm), T.-W. Chen (TUM/MPA), H.-Y. Hsiao, Y.-C. Pan, C.-C. Ngeow, W.-J. Hou, C.-S. Lin, H.-C. Lin, and J.-K. Guo (IANCU) report: We observed the field of ZTF23aabmzlp/AT2023azs (Andreoni et al., GCN 33229), using the Lulin One-meter Telescope (LOT) at Lulin Observatory, Taiwan, to obtain g,r,i-band images as part of the Kinder collaboration (Chen et al., AstroNote 2021-92). The first epoch of observations started at 20:51 UT on 28 of January 2023 (MJD = 59972.869), 0.61 days after the first detection from ZTF. The images were combined from 3 frames with 300 sec exposure time for g and r bands, and 2 frames with 300 sec exposure time for i band, taken under poor seeing conditions (4".0 average) and at a median airmass of 1.5. The second epoch was performed at 20:38 UT on 29 of January 2023 (MJD = 59973.860). The images were combined from 2 frames with 300 sec exposure time for each band, taken under variable seeing conditions (1".8 average) and at a median airmass of 1.5. We used PSF photometry to measure the transient brightness with template subtraction using the SDSS images, and derived the following preliminary magnitudes and 3-sigma limits (all in the AB system): 2023-01-28: g > 20.18 mag, r > 19.21 mag, and i > 19.13 mag. 2023-01-29: g > 21.82 mag, r = 21.78 +/- 0.15 mag, and i = 21.34 +/- 0.13 mag. Given magnitudes are calibrated against SDSS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.01 mag in the direction of the counterpart (Schlafly & Finkbeiner 2011). Our measurements of the photometric evolution of ZTF23aabmzlp/AT2023azs are consistent with previous optical observations reported from Kumar et al., GCN 33230; Gupta et al., GCN 33237; Pankov et al., GCN 33239; Strausbaugh et al., GCN 33241.