arXiv subjects

Youssef Eweis

Publications and source records attributed to Youssef Eweis.

2 recordsLinked to original sources

arXiv2026

Superlinear Type II Superluminous Supernovae 2017fck and 2019cmv: A Possible Origin from Interacting Thermonuclear Supernovae

Additional power sources to traditional supernovae (SNe) are necessary to account for the extreme luminosities of superluminous SNe (SLSNe). A main power source for hydrogen-rich SLSNe (SLSNe-II) is thought to be circumstellar material (CSM) interaction. However, the nature of underlying SNe and their progenitor systems remain elusive as they are hidden below strong CSM signatures. Here, we present optical photometry and spectroscopy of SLSNe-II 2017fck and 2019cmv. They are characterized by post-maximum "superlinear" light curves which we also identify in a sample of Type Ia SNe interacting with CSM (SNe Ia-CSM), along with their light-curve correlations and spectral similarities. Thus, we compute a numerical light-curve model grid of SNe Ia-CSM with various SN Ia subtypes and CSM distributions. Our model grid spans the observed parameter space of SNe Ia-CSM in terms of their rise times, peak luminosities, and decline rates with a wide CSM mass range of $\sim2-11$ M$_\odot$, indicating the diversity in their progenitor systems. For SNe 2017fck and 2019cmv, we infer high CSM masses of $\sim11$ and $6$ M$_\odot$, respectively, which might be produced during the common envelope evolution of a white dwarf and massive ($\geq8$ M$_\odot$) or intermediate-mass ($<8$ M$_\odot$) companion. Together with the proposed connection of SLSN-II 2006gy to SNe Ia-CSM, SNe 2017fck and 2019cmv may offer a possible thermonuclear origin for superlinear SLSNe-II with peak optical luminosities up to $10^{44}$ erg s$^{-1}$.

astro-ph.HE↗

arXiv2020

Supernova 2018cuf: A Type IIP supernova with a slow fall from plateau

We present multi-band photometry and spectroscopy of SN 2018cuf, a Type IIP ("P" for plateau) supernova (SN) discovered by the Distance Less Than 40 Mpc survey (DLT40) within 24 hours of explosion. SN 2018cuf appears to be a typical Type IIP SN, with an absolute $V$-band magnitude of $-$16.73 $\pm$ 0.32 at maximum and a decline rate of 0.21 $\pm$ 0.05 mag/50d during the plateau phase. The distance of the object is constrained to be 41.8 $\pm$ 5.7 Mpc by using the expanding photosphere method. We use spectroscopic and photometric observations from the first year after the explosion to constrain the progenitor of SN 2018cuf using both hydrodynamic light curve modelling and late-time spectroscopic modelling. The progenitor of SN 2018cuf was most likely a red supergiant of about 14.5 $\rm M_{\odot}$ that produced 0.04 $\pm$ 0.01 $\rm M_{\odot}$ $\rm ^{56}Ni$ during the explosion. We also found $\sim$ 0.07 $\rm M_{\odot}$ of circumstellar material (CSM) around the progenitor is needed to fit the early light curves, where the CSM may originate from pre-supernova outbursts. During the plateau phase, high velocity features at $\rm \sim 11000\ km~s^{-1}$ are detected both in the optical and near-infrared spectra, supporting the possibility that the ejecta were interacting with some CSM. A very shallow slope during the post-plateau phase is also observed and it is likely due to a low degree of nickel mixing or the relatively high nickel mass in the SN.

astro-ph.HE↗