ASASSN-25bz: new SU UMa-type dwarf nova

ASASSN-25bz (=AT 2025lkr) was discovered at 14.8 mag on 20 May by ASAS-SN. The suggested outburst amplitude is ~8 mag according to the VSX. ASAS-SN  reported to the TNS that this could be a classical nova based on its low Galactic latitude b~-2.0 deg.

I obtained the time-resolved observations of ASASSN-25bz with the SAAO/Lesedi telescope on 26 and 27 May. Its light curve shows a prominent ordinary superhump with an amplitude of 0.15 mag and a period of ~0.0561(1) d (1-d aliases are possible).  The optical spectrum obtained on 23 May with the SAAO/Lesedi telescope is dominated by Balmer absorption lines.

Thus, I conclude that ASASSN-25bz is a new SU UMa-type dwarf nova. The system is around 15.6 mag.

Best regards,

Yusuke