SN 2022xlp: The second-known well-observed, intermediate-luminosity Iax supernova

¹ Department of Experimental Physics, Institute of Physics, University of Szeged, Dóm tér 9, 6720 Szeged, Hungary
² Baja Astronomical Observatory of the University of Szeged, Szegedi út, Kt. 766, 6500 Baja, Hungary
³ HUN-REN CSFK Konkoly Observatory, Konkoly Thege M. út 15-17, Budapest 1121, Hungary
⁴ HUN-REN-SZTE Stellar Astrophysics Research Group, Szegedi út, Kt. 766, 6500 Baja, Hungary
⁵ Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205, USA
⁶ Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065, USA
⁷ Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA
⁸ Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain
⁹ Institut d’Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain
¹⁰ Department of Physics and Astronomy, Rutgers, the State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019, USA
¹¹ Las Cumbres Observatory, 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575, USA
¹² Department of Physics, University of California, Santa Barbara, CA 93106-9530, USA
¹³ Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA
¹⁴ ELTE Eötvös Loránd University, Institute of Physics and Astronomy, Pázmány Péter sétány 1A, Budapest 1117, Hungary
¹⁵ National Astronomical Research Institute of Thailand (NARIT), Chiang Mai 50180, Thailand

^⋆ Corresponding author: dbanhidi@titan.physx.u-szeged.hu

Received: 27 January 2025
Accepted: 18 July 2025

Abstract

Context. We present a detailed multicolor photometric and spectroscopic analysis of type Iax supernova SN 2022xlp. With a V-band absolute magnitude light curve peaking at M_max(V) =  − 16.04 ± 0.25 mag, this object is regarded as the second determined well-observed Iax supernova in the intermediate luminosity range after SN 2019muj.

Aims. Our research aims to explore the question of whether the physical properties vary continuously across the entire luminosity range. We also investigate the chemical abundance profiles and the characteristic physical quantities of the ejecta, followed by tests of the predictions of hydro simulations.

Methods. The pseudo-bolometric light curve was calculated using optical (BgVriz) and UV (Swift UVOT UVW2,UVM2, UVW1,U,B) light curves and fits with a radiation diffusion Arnett model to constrain the average optical opacity, ejected mass, and initial nickel mass produced in the explosion. We analyzed the color evolution of SN 2022xlp and compared it with that of other Iax supernovae with different peak luminosities. We used the spectral tomography method to determine the radial profiles of physical properties and abundances of the ejecta, comparing them with a set of hydrodynamic pure deflagration models.

Results. SN 2022xlp shows a relatively rapid color evolution due to the decreasing photospheric temperature in the early phase. The estimated bolometric flux peaks at 8.87 × 10⁴¹ erg s⁻¹ and indicates the production of radioactive nickel as M(⁵⁶Ni) = 0.0215 ± 0.009 M_⊙. According to the best-fit model, the explosion energy is (2.066 ± 0.236)×10⁴⁹ erg and the ejecta mass is 0.142 ± 0.015 M_⊙. The performed spectral tomography analysis shows that the determined physical quantities agree well with the predictions of the deflagration simulations, with modifications regarding the increased Na abundance and the more massive outer layers. SN 2022xlp bridges the previously existing luminosity gap, together with SN 2019muj, and supports the assumption of continuous variation in the physical properties across the SN Iax subclass.