My projects
My main research focus is on supernova explosions, specially those generated by the collapse of the core of massive stars! These events are so bright that we can see them at very large distances, being sometimes as bright as all the stars in their host galaxies. Supernovae are also one of the main mechanisms for generating and spreading elements throughout the Universe.
One of the key points of my research is to find which are the stars the generate the different types of observed supernovae. To look for the connections between the supernova types and their progenitor stars, I analyze the environments around the explosion and their absolute and relative rates.
Analysis of ASASSN supernova environments with VLT+MUSE
The analysis of core-collapse supernova (CCSN) environments can provide important information on the life cycle of massive stars and constrain the progenitor masses of these powerful explosions.
I this work, we analyze 113 galaxies observed by MUSE that hosted 114 CCSNe (79 II, 9 IIn, 8 IIb, 4 Ic, 7 Ib, 3 Ibn, 2 Ic-BL, 1 Ibc and
1 SLSN) detected or discovered by the ASAS-SN survey between 2014 and 2018. The majority of the galaxies were observed by the
the All-weather MUse Supernova Integral field Nearby Galaxies (AMUSING) survey.
We found that SESNe occur in environments with higher values of SFR, Hα EW, and oxygen abundance than SNe II and IIn/Ibn. We found a statistically significant difference between the distributions of oxygen abundance between SESNe and II. The distributions of SNe II and IIn are very similar, indicating that these events explode in similar environments. Between the SESNe, SNe Ic have higher median values of SFR, Hα EW, and oxygen abundance than SNe Ib, although no statistically significant difference
between the distributions is found. SNe IIb are related to environments with similar values of SFR and Hα EW to SNe Ib, and similar oxygen abundance values to SNe Ic. While there are some indications that the different CCSN types have different progenitor properties from their environments, the fact that the differences between the distributions are not statistically significant suggests that the progenitors differences in masses, age and metallicity is not huge. We also show that the luminosity of SESNe correlates with the oxygen abundance at their environments, suggesting an intrinsic relation between metallicity and 56Ni produced in these events.
Link for the paper: https://doi.org/10.1051/0004-6361/202346512
SN 2011fh: a true SN or an impostor?
In this work, we present 10 yr of observations of SN 2011fh, an interacting transient with spectroscopic and photometric similarities to the famous SN 2009ip.
SN 2011fh had an Mr ∼ −16 mag brightening event, followed by a brighter Mr ∼ −18 mag luminous outburst. SN 2011fh has spectra dominated by narrow to intermediate Balmer emission lines throughout its evolution, with P Cygni profiles indicating fast-moving material at ∼6400 km s−1.
HST/WFC3 observations from 2016 October revealed a bright source with MF814W ≈ −13.3 mag, indicating that we are seeing the ongoing interaction of the ejecta with the circumstellar material or that the star might be going through an eruptive phase five years after the luminous outburst of 2011. Using HST photometry of the stellar cluster around SN 2011fh, we estimated an age of ∼4.5 Myr for the progenitor, which implies a stellar mass of ∼60 M⊙, using single-star evolution models, or a mass range of 35–80 M⊙, considering a binary system.
We also show that the progenitor of SN 2011fh exceeded the classical Eddington limit by a large factor in the months preceding the luminous outburst of 2011, suggesting strong super-Eddington winds as a possible mechanism for the observed mass loss.
These findings favor an energetic outburst in a young and massive star, possibly a luminous blue variable.
Link for the paper: https://iopscience.iop.org/article/10.3847/1538-4357/ac562d
