A Late-Time View of the Progenitors of Five Type IIP Supernovae

TL;DR

This study uses late-time HST observations to confirm progenitors of five Type IIP supernovae, refine their properties, and assess dust effects, providing improved constraints on their initial masses and progenitor identifications.

Contribution

It presents new late-time imaging data and analysis techniques that confirm progenitors and refine their properties, improving understanding of Type IIP supernova origins.

Findings

Confirmed progenitor disappearances for SNe 2003gd, 2004A, 2005cs

Doubted progenitor identification for SN 1999ev

Estimated initial masses of progenitors between 8.4 and 12 solar masses

Abstract

The acquisition of late-time imaging is an important step in the analysis of pre-explosion observations of the progenitors of supernovae. We present late-time HST ACS WFC observations of the sites of five Type IIP SNe: 1999ev, 2003gd, 2004A, 2005cs and 2006my. Observations were conducted using the F435W, F555W and F814W filters. We confirm the progenitor identifications for SNe 2003gd, 2004A and 2005cs, through their disappearance. We find that a source previously excluded as being the progenitor of SN 2006my has now disappeared. The late-time observations of the site of SN 1999ev cast significant doubt over the nature of the source previously identified as the progenitor in pre-explosion WFPC2 images. The use of image subtraction techniques yields improved precision over photometry conducted on just the pre-explosion images alone. In particular, we note the increased depth of detection limits derived on pre-explosion frames in conjunction with late-time images. We use SED fitting techniques to explore the effect of different reddening components towards the progenitors. For SNe 2003gd and 2005cs, the pre-explosion observations are sufficiently constraining that only limited amounts of dust (either interstellar or circumstellar) are permitted. Assuming only a Galactic reddening law, we determine the initial masses for the progenitors of SNe 2003gd, 2004A, 2005cs and 2006my of 8.4+/-2.0, 12.0+/-2.1, 9.5(+3.4,-2.2) and 9.8+/-1.7Msun, respectively.