Spectroscopic classification of the transient ZTF21aajzhgk/AT2021clj
ATel #14423; Monika Soraisam (NCSA/UIUC), Chien-Hsiu Lee (NOIRLab), Gautham Narayan (UIUC), Thomas Matheson, Abhijit Saha (NOIRLab), Thomas G. Brink, Kishore C. Patra, Thomas de Jaeger, WeiKang Zheng, Benjamin E. Stahl, Alexei V. Filippenko (UC Berkeley)
on 25 Feb 2021; 18:01 UT
Credential Certification: Monika Soraisam (soraisam@illinois.edu)
Subjects: Optical, Nova, Transient
We report the spectroscopic observation of ZTF21aajzhgk/AT2021clj (RA 0h42m48.29s, Dec +41d19m37.47s; J2000). The source was flagged from the ZTF public alert stream by a filter designed to find transients in M31 on the ANTARES alert-broker (https://antares.noirlab.edu/loci/ANT2021fchbe).
On 2021 Feb. 18 UT, we obtained a spectrum of this source with the Kast double spectrograph on the Shane 3 m telescope at Lick Observatory. The spectrum shows Balmer emission lines superposed on a flat continuum, with the FWHM of the H-alpha line around 1600 km/s, as well as hints of emission from the Paschen series between 8500 and 9500 Å. The lines are blueshifted with a radial velocity (based on H-beta) around -300 km/s, consistent with the systemic velocity of M31's center of mass. Overall, the spectrum is thus consistent with a nova in M31.
