arXiv subjects

S. P. Cosentino

Publications and source records attributed to S. P. Cosentino.

7 recordsLinked to original sources

arXiv2026

High-energy neutrino flux from SN2024ggi: constraints from semi-analytic modeling of its post-explosive emission

Hydrogen-rich supernovae can efficiently accelerate particles when the expanding ejecta interact with the surrounding circumstellar medium (CSM), producing high-energy (TeV--PeV) neutrinos. In this work we investigate the nearby SN~2024ggi, whose proximity and clear signatures of ejecta--CSM interaction make it a promising candidate for studying high-energy ($ν$) emission. We apply a new semi-analytical model that consistently links the electromagnetic and neutrino emission components, allowing us to constrain the main explosion parameters, including the kinetic energy, ejecta mass, progenitor radius, and nickel yield. The predicted high-energy ($ν$) fluence at Earth peaks at TeV energies and remains below the sensitivity of current detectors. However, the modeling establishes a robust framework for interpreting future signals from nearby interacting supernovae and fine-tuning observational strategies for next-generation multi-messenger facilities such as IceCube-Gen2 and KM3NeT/ARCA.

astro-ph.HE↗

arXiv2026

Physical properties of long-rising type II supernovae -- Bayesian analytic modeling and spectrophotometric correlations

Supernova (SN) 1987A, with its long-rising ($\gtrsim$40 days) light curve, defines a rare subclass of type II SNe known as 1987A-like events. Representing only 1-3 percent of all core-collapse SNe and often found in low-metallicity environments, their large diversity suggests a wide range of progenitor and explosion properties. This study aims to improve the understanding of 1987A-like SNe by characterizing their explosion parameters, including kinetic energy, ejected mass, progenitor radius at explosion, and synthesized $^{56}$Ni mass. Additionally, it seeks to identify systematic trends in both the physical properties and the observed features of these peculiar events. A new Bayesian parameter estimation method, based on our $^{56}$Ni-dependent analytical model for hydrogen-rich SNe, is applied to derive explosion parameters from the light curves and expansion velocities of one of the largest and most comprehensive 1987A-like SN samples to date. These data are measured through a consistent analysis of observations available in the literature. The analysis reveals a heterogeneous population that nevertheless clusters into two main groups: (i) lower-energy explosions with modest $^{56}$Ni yields ($\sim$0.07 M$_\odot$), similar to SN 1987A, and (ii) more energetic events (up to $\sim$5 foe) with larger nickel production and, in some cases, unusually extended progenitors. We confirm a robust correlation between $^{56}$Ni mass, peak luminosity, and explosion energy, as well as between ejecta mass and recombination timescale. An anti-correlation between Ba II line strength and photospheric velocity indicates that stronger Ba II absorptions in 1987A-like SNe arise from more compact, slowly expanding ejecta. Our study underscores the need to extend analytical frameworks to include additional power sources, enabling scalable and accurate modeling of the growing number of peculiar transients.

astro-ph.HE↗

arXiv2026

Light-Curve and Spectral Properties of Type II Supernovae from the ATLAS survey

Type II supernovae (SNe II) are the most common terminal stellar explosions in the Universe. With SNe now being detected within days after explosion, there is growing evidence that the majority of Type II SNe show signs of interaction with a confined, dense cirumstellar material (CSM) in the first few days post explosion. In this work we aim to bridge the gap between single SN studies showing early-time interaction in their spectra, and the statistical studies of early-time SN light curves, which imply the existence of CSM. We present a sample of 68 Type II SNe with both early photometric data, obtained with the ATLAS survey, and spectroscopic data, obtained with the ePESSTO+ collaboration. A subset of the sample is classified based on the presence or absence of narrow spectral features with electron-scattered broadened wings in the early spectra, indicative of interaction with CSM. We characterise the photometric and spectroscopic properties of the sample by measuring rise times to maximum light, peak magnitudes, decline rates and line velocities. Additionally, we measure the ratio of absorption to emission (a/e) of the H alpha P-Cygni profile. Our analysis reveals that SNe II showing early spectroscopic signs of interaction with CSM decline faster and are brighter than those without. However no difference is found in rise times between the two groups. A clear separation is observed in the a/e ratio: SNe with signs of interaction exhibit lower a/e ratios at all epochs compared to those without. Our results highlight that understanding SN II ejecta-CSM interaction requires large, uniform samples of photometric and spectroscopic data, such as the one presented in this work.

astro-ph.SR↗

arXiv2025

High-Energy Neutrinos by Hydrogen-rich Supernovae interacting with low-massive Circumstellar Medium: The Case of SN 2023ixf

In hydrogen-rich (H-rich) Supernova (SN) events, the collision between the H-rich ejecta and the Circum-Stellar Medium (CSM) can accelerate particles and produce high-energy neutrinos (HE-$ν$, TeV-PeV) through proton-proton inelastic scattering. Despite understanding the production mechanism of these neutrinos, the lack of direct observations raises questions about particle acceleration efficiency and the involved astrophysical conditions. This study focuses on neutrino emission from H-rich SNe with low-mass CSM, such as SN 2023ixf. We developed a semi-analytical model to characterize the progenitor and CSM at the explosion time, allowing us to infer the expected neutrino flux at Earth during the SN's interaction phase. Our model shows that neutrino emission depends not only on shock velocity and CSM mass but also on the spatial matter distribution of the CSM. By analysing the bolometric light curve of SN 2023ixf beyond 100 days post-explosion, we find that its ejecta, consisting of $9\,\text{M}_{\rm \odot}$ (including $0.07\,\text{M}_{\rm \odot}$ of radioactive $^{56}$Ni) and having a kinetic energy of $1.8\,\text{foe}$, collides with a low-mass CSM of $0.06\,\text{M}_{\rm \odot}$ distributed according to a power-law density profile with an exponent of $s=2.9$. Through these parameters, we estimate that up to $4\pm1\times 10^{-2}$ muon (anti-)neutrino events could be detected by IceCube within 50 days post-explosion. Although the predicted flux ($\lesssim 3\times 10^{-9}\,\text{GeV} \, \text{cm}^{-2} \, \text{s}^{-1}$) is below current IceCube sensitivity, future telescopes like IceCube-Gen2 and KM3NeT could detect HE-$ν$ from similar SN events.

astro-ph.HE↗

arXiv2025

Long-rising Type II supernovae resembling supernova 1987A -- II. A new analytical model to describe these events

With the aim of improving our knowledge on supernova (SN) 1987A-like objects and, more in general, on H-rich SNe, we have developed a new analytic model to describe their post-explosive evolution. The distinctive features of this model are the possibility to evaluate the emitted luminosity and the SN expansion velocity, taking into account the recombination of the ejected material, the heating effects due to the \chem{56}{Ni} decay in the computation of the recombination front position, and the presence of an outer thin shell not-homologously expanding. In this paper, we present the model and a comparison with observations of SN 1987A, showing that its bolometric light curve and expansion velocity are accurately reproduced by the model. We also investigate the modeling degeneration problem in H-rich SNe and the possibility to ``standardize'' the subgroup of SN 1987A-like objects. Moreover we present new Ni-dependent relationships, based on our model, which link some features of the bolometric light curve of 1987A-like SNe (namely, the peak luminosity and its width) with the main physical properties of their progenitor at the explosion (i.e.~the ejected mass, the explosion energy, the progenitor radius at the explosion, and the amount of \chem{56}{Ni} present in the ejecta), showing that such relations are in excellent agreement with observations of real SNe. From our model, we also deduce new scaling relations which may be used for estimating the main SN progenitor's physical properties at the explosion, once only the photometric behaviour of the SN 1987A-like object is known.

astro-ph.HE↗

arXiv2024

The fast rise of the unusual Type IIL/IIb SN 2018ivc

We present an analysis of the photometric and spectroscopic dataset of the Type II supernova (SN) 2018ivc in the nearby (10 Mpc) galaxy Messier 77. Thanks to the high cadence of the CHASE survey, we observed the SN rising very rapidly by nearly three magnitudes in five hours (or 18 mag d$^{-1}$). The $r$-band light curve presents four distinct phases: the maximum light is reached in just one day, then a first, rapid linear decline precedes a short-duration plateau. Finally, a long, slower linear decline lasted for one year. Following a radio rebrightening, we detected SN 2018ivc four years after the explosion. The early spectra show a blue, nearly featureless continuum, but the spectra evolve rapidly: after about 10 days a prominent H$α$ line starts to emerge, with a peculiar profile, but the spectra are heavily contaminated by emission lines from the host galaxy. He I lines, namely $λλ$5876,7065, are also strong. On top of the former, a strong absorption from the Na I doublet is visible, indicative of a non-negligible internal reddening. From its equivalent width, we derive a lower limit on the host reddening of $A_V\simeq1.5$ mag, while from the Balmer decrement and a match of the $B-V$ colour curve of SN 2018ivc to that of the comparison objects, a host reddening of $A_V\simeq3.0$ mag is obtained. The spectra are similar to those of SNe II, but with strong He lines. Given the peculiar light curve and spectral features, we suggest SN 2018ivc could be a transitional object between the Type IIL and Type IIb SNe classes. In addition, we found signs of interaction with circumstellar medium in the light curve, making SN 2018ivc also an interacting event. Finally, we modelled the early multi-band light curves and photospheric velocity of SN 2018ivc to estimate the explosion and CSM physical parameters.

astro-ph.HE↗

arXiv2023

Long-rising Type II supernovae resembling supernova 1987A -- I. A comparative study through scaling relations

With the aim of improving our knowledge about their nature, we conduct a comparative study on a sample of long-rising Type II supernovae (SNe) resembling SN 1987A. To do so, we deduce various scaling relations from different analytic models of H-rich SNe, discussing their robustness and feasibility. Then we use the best relations in terms of accuracy to infer the SN progenitor's physical properties at the explosion for the selected sample of SN 1987A-like objects, deriving energies of $\sim 0.5$-$15$ foe, radii of $\sim 0.2$-$100 \times 10^{12}$ cm, and ejected masses of $\sim 15$-$55$\msun. Although the sample may be too small to draw any final conclusion, these results suggest that (a) SN 1987A-like objects have parameters at explosion covering a wide range of values; (b) the main parameter determining their distribution is the explosion energy; (c) a high-mass ($\gtrsim 30$\,\Msun), high-energy ($\gtrsim 10$\,foe) tail of events, linked to extended progenitors with radii at explosion $\sim 10^{13}$-$10^{14}$\,cm, challenge standard theories of neutrino-driven core-collapse and stellar evolution. We also find a correlation between the amount of $^{56}$Ni in the ejecta of the SN 1987A-like objects and the spectrophotometric features of the SN at maximum, that may represent a tool for estimating the amount of $^{56}$Ni in the SN ejecta whitout having information on the tail luminosity.

astro-ph.HE↗