AstroNote 2022-41

We report near-infrared (NIR) spectroscopy of AT 2022cmc obtained on 2022 Feb 16 15:22 UT, using the Near-Infrared Echellette Spectrometer (NIRES) on the Keck II telescope. An A0V star HIP 68120 was observed after the target for telluric calibration. We used Spextool (Cushing et al., 2004) to reduce the spectra and xtellcor (Vacca et al., 2003) for telluric correction. The spectrum presented here has been trimmed to remove noisy regions in the telluric bands. The spectrum in general has SNR ~ 3 per pixel as the observation was cut short due to high humidity. To help with visualization, we smoothed the spectrum using a Savitzky-Golay filter with a 6-pixel bandwidth and 2nd degree polynomial. 

The spectrum shows a relatively featureless continuum. There may be a broad absorption feature at around 1.2 micron in the observer frame. If this corresponds to the 1.08 micron He+metal line complex, then the redshift of this source is at z ~ 0.1.