AstroNote 2024-63

AT2024diq was first discovered by ATLAS-CHL on 2024 February 28 at 08:09:46 UT with a magnitude of o=17.29. Following the ATLAS discovery, the fully-robotic SAAO 1-m Lesedi telescope equipped with the Mookodi low-resolution (R~172) spectrograph and imager was automatically triggered as part of the SAAO's Intelligent Observatory (IO) program and obtained 2x600s spectra beginning at 01:56:28 UT on 2024 February 29. The combined spectrum shows the presence of emission lines corresponding to the Balmer lines of Hydrogen, HeII 4686, and CIII/NIII 4647, all at a common redshift of z=0.0146 and which we regard as the redshift to AT2024diq. The presence of HeII 4686  and CIII/NIII 4647 emission lines at such early times are consistent with a flash-ionised Type II supernova. Further follow-up is encouraged. 

We acknowledge the SAAO IO team including S. Potter, N. Erasmus, C. van Gend, S. Chandra, H. Worters, M. Hlakola and R. Julie for their role in making these observations possible.