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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.
Herein we analyse late-time (post-plateau; 103 < t < 1229 d) optical spectra of low-redshift (z < 0.016), hydrogen-rich Type IIP supernovae (SNe IIP). Our newly constructed sample contains 91 nebular spectra of 38 SNe IIP, which is the largest datase
Type II-plateau supernovae (SNe IIP) are the results of the explosions of red supergiants and are the most common subclass of core-collapse supernovae. Past observations have shown that the outer layers of the ejecta of SNe IIP are largely spherical,
We review all the models proposed for the progenitor systems of Type Ia supernovae and discuss the strengths and weaknesses of each scenario when confronted with observations. We show that all scenarios encounter at least a few serious diffculties, i
A non-local-thermodynamic-equilibrium (NLTE) level population model of the first and second ionisation stages of iron, nickel and cobalt is used to fit a sample of XShooter optical + near-infrared (NIR) spectra of Type Ia supernovae (SNe Ia). From th
We compute an extensive set of early-time spectra of supernovae interacting with circumstellar material using the radiative transfer code CMFGEN. Our models are applicable to events observed from 1 to a few days after explosion. Using these models, w