Photometry and Spectroscopy of SN 2024pxl: A Luminosity Link Among Type Iax Supernovae

TL;DR

SN 2024pxl, a nearby Type Iax supernova, exhibits intermediate luminosity, spectral features, and velocities, providing evidence for a continuum in this supernova class and supporting weak deflagration models.

Contribution

This study presents detailed photometric and spectroscopic observations of SN 2024pxl, revealing its intermediate properties and strengthening the luminosity link among Type Iax supernovae.

Findings

SN 2024pxl has an intermediate luminosity and light curve.

Spectral features show a mix of high- and low-luminosity Type Iax characteristics.

Ejecta velocities and spectral evolution support pure deflagration models.

Abstract

We present extensive ultraviolet to optical photometric and optical to near-infrared (NIR) spectroscopic follow-up observations of the nearby intermediate-luminosity ($M_V = -16.81\pm0.19$~mag) Type Iax supernova (SN) 2024pxl in NGC 6384. SN~2024pxl exhibits a faster light curve than the high-luminosity members of this class, and slower than low-luminosity events. The observationally well-constrained rise time of $\sim$11 days and an estimated synthesized $^{56}$Ni mass of 0.03\, M$_\odot$, based on analytical modeling of the integrated spectral energy distribution light curve, are consistent with models of the weak deflagration of a carbon-oxygen white dwarf. Our optical spectral sequence of SN~2024pxl shows weak \ion{Si}{2} lines and spectral evolution similar to other high-luminosity Type Iax SNe, but also a prominent early-time \ion{C}{2} line, like lower-luminosity Type Iax SNe. The late-time optical spectrum of SN~2024pxl closely matches that of SN~2014dt, and its NIR spectral evolution aligns with that of other well-studied, high-luminosity Type Iax SNe. The spectral-line expansion velocities of SN~2024pxl are at the lower end of the Type Iax SN velocity distribution, and the velocity distribution of iron-group elements compared to intermediate-mass elements suggests that the ejecta are mixed on large scales, as expected in pure deflagration models. SN~2024pxl exhibits characteristics intermediate between those of high-luminosity and low-luminosity Type~Iax SNe, further establishing a link across this diverse class.