Confirmation of spectroscopic classification of PGIR21fjn/AT2021kgk as a classical nova
ATel #14578; N. Blagorodnova (Radboud University), F. Comeron (ESO, DE), D. Galadi-Enriquez (CAHA, Spain), S. Gongora (CAHA, Spain) J. Ardevol (University of Barcelona, UB), F. Asensio (UB), A. Caro (UB), M. Carretero (UB), M. del Alcazar (UB), J. Donada (UB), J. Garcia de la Torre (UB), J. Fernandez-Vilana (UB), C. Jimenez-Palau (UB), I. Mases (UB), J. Miro (UB), R. Prat (UB), C. Salas (UB), C. Soriano (UB), P. Bordas (UB), J. Carbajo (UB), D. del Ser (UB), A. Ferre-Mateu (UB), F. Figueras (UB), X. Luri (UB), O. Jimenez-Arranz (UB), T. Santana-Ros (UB)
on 26 Apr 2021; 16:02 UT
Credential Certification: Nadejda Blagorodnova (N.Blagorodnova@astro.ru.nl)
Subjects: Optical, Nova, Transient
Referred to by ATel #: 14647
We report our analysis on the spectrum of the highly reddened Galactic transient PGIR21fjn/AT2021kgk reported on ATel #14567. The data were obtained from 2021-04-23.06 UT to 2021-04-23.18 UT (~3.6 days after discovery) using CAFOS, the optical imager and low-resolution spectrograph of the 2.2m telescope at Calar Alto Observatory (CAHA; https://www.caha.es/telescope-2-2m/cafos).
The grism R400 was used, providing a resolution of R~250 per resolution element over the interval 500-1000 nm with a 1.5 arcsec slit. A relative flux calibration was carried out by observing the spectrophotometric standard BD+25 3941 with the same setup and through a similar airmass, in between two AT2021kgk exposures. Our estimated fluxes are ~5 mJy (m_AB ~ 14.6) in the immediate vicinity of the H alpha line, steeply rising to ~250 mJy (m_AB ~ 10.4) in a pseudo-continuum interval at 850 nm.
Once corrected for Galactic extinction of Av=18.528 mag (Schafly et al. 2011), the spectrum shows broad emission lines related to H, O I, N I, NII, Mg II, and possibly [Ar III] with P-Cygni profiles. The H alpha line is detected in emission with a FWHM ~1630 km/s (corrected for instrumental resolution) and a rest wavelength consistent with Galactic redshift. The P-Cygni profile of the line shows a minimum at ~-1900km/s. The classification is consistent with AT2021kgk being a Classical Nova, in agreement with ATel #14570,#14576 and ATel #14574.
The observations were part of the observational work of under-graduates and graduate students of the University of Barcelona while attending the Calar Alto Academy (https://www.caha.es/news/releases-mainmenu-163/11540-calar-alto-academy). We thank the Calar Alto staff for rapidly approving and scheduling these observations.
