Spectroscopic classification of the bright and nearby AT2026fhw with MDM/OSMOS
ATel #17737; R. B. Effress, B. T. Gebreamlak, B. O. Goldman, T. Goodman, J. Kalish, L. Koo, T. Lack, S. A. Lawsky, S. L. Manyan, M. Nebart, K. N. Oqueli-White, A. Ramadorai, N. A. Rodgers, T. A. Sabin, E. Sharman, C. Wu, L. Zheng, R. Zheng, N. Aftab, D. Schiminovich, K. De (Columbia University)
on 2 Apr 2026; 23:19 UT
Credential Certification: Kishalay De (kde@flatironinstitute.org)
Subjects: Optical, Supernovae
We report spectroscopic observations of the nearby, bright transient AT2026fhw with OSMOS on the MDM 2.4 Hiltner telescope. The source was discovered by the ATLAS survey (Tonry et al., TNS Report No. 294191) as a young supernova candidate in a galaxy at z = 0.019.
We observed AT2026fhw as part of an undergraduate class training session with the OSMOS spectrograph on the MDM 2.4m Hiltner telescope. Observations were obtained on UT 2026-03-21 using the blue grism and the 1.2 inner slit, providing a wavelength coverage of 4000 - 7000 Angstrom at a spectral resolution R ~ 1000.
The data was reduced using a custom spectroscopic pipeline. The reduced spectrum shows broad absorption features of Si II, S II and Fe II with velocities of 11,000 km/s at the redshift of the host galaxy. The spectrum is consistent with a normal Type Ia supernova a few days before peak brightness.
