M. Pumo - Academia.edu (original) (raw)
Papers by M. Pumo
Monthly Notices of the Royal Astronomical Society
A deep survey of the Large Magellanic Cloud at ∼0.1–100 TeV photon energies with the Cherenkov Te... more A deep survey of the Large Magellanic Cloud at ∼0.1–100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3–2.4 pending a flux increase by a factor of >3–4 over ∼2015–2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10 GeV spectrum has a soft photon index ∼2.7, but degree-scal...
We investigate the role played by initial clumping of ejecta and by efficient acceleration of cos... more We investigate the role played by initial clumping of ejecta and by efficient acceleration of cosmic rays (CRs) in determining the density structure of the post-shock region of a Type Ia supernova remnant (SNR) through detailed 3D MHD modeling. Our model describes the expansion of a SNR through a magnetized interstellar medium (ISM), including the initial clumping of ejecta and the effects on shock dynamics due to back-reaction of accelerated CRs. The model predictions are compared to the observations of SN 1006. We found that the back-reaction of accelerated CRs alone cannot reproduce the observed separation between the forward shock (FS) and the contact discontinuity (CD) unless the energy losses through CR acceleration and escape are very large and independent of the obliquity angle. On the contrary, the clumping of ejecta can naturally reproduce the observed small separation and the occurrence of protrusions observed in SN 1006, even without the need of accelerated CRs. We conclude that FS-CD separation is a probe of the ejecta structure at the time of explosion rather than a probe of the efficiency of CR acceleration in young SNRs.
Supernova remnats (SNRs) show a complex morphology characterized by an inhomogeneous spatial dist... more Supernova remnats (SNRs) show a complex morphology characterized by an inhomogeneous spatial distribution of ejecta, believed to reflect pristine structures and features of the progenitor supernova (SN) explosion. Filling the gap between SN explosions and their remnants is very important for a comprehension of the origin of present-day structure of ejecta in SNRs and to probe and constraint current models of SN explosions. The SNR Cassiopeia A (Cas A) is an attractive laboratory for studying the SNe-SNRs connection, being one of the best studied SNRs for which its 3D structure is known. We present a three-dimensional hydrodynamic model describing the evolution of Cas A from the immediate aftermath of the SN explosion to its expansion through the interstellar medium, taking into account the distribution of element abundances of the ejecta, the backreaction of accelerated cosmic rays at the shock front, and the deviations from equilibrium of ionizazion for the most important elements. We use the model to derive the physical parameters characterizing the SN explosion and reproducing the today morphology of Cas A
Super-AGB stars can conclude their evolution either as neon -oxygen white dwarfs or as electron-c... more Super-AGB stars can conclude their evolution either as neon -oxygen white dwarfs or as electron-capture supernovae. We discuss the po ssible consequences of the existence of this “double final fate” in the self-enrichment of globular clusters and in the nucleosynthesis process of s-nuclei.
The Astrophysical Journal, 2016
The remnants of core-collapse supernovae (SNe) have complex morphologies that may reflect asymmet... more The remnants of core-collapse supernovae (SNe) have complex morphologies that may reflect asymmetries and structures developed during the progenitor SN explosion. Here we investigate how the morphology of the supernova remnant Cassiopeia A (Cas A) reflects the characteristics of the progenitor SN with the aim of deriving the energies and masses of the post-explosion anisotropies responsible for the observed spatial distribution of Fe and Si/S. We model the evolution of Cas A from the immediate aftermath of the progenitor SN to the three-dimensional interaction of the remnant with the surrounding medium. The post-explosion structure of the ejecta is described by small-scale clumping of material and larger-scale anisotropies. The hydrodynamic multi-species simulations consider an appropriate post-explosion isotopic composition of the ejecta. The observed average expansion rate and shock velocities can be well reproduced by models with ejecta mass M ej ≈4M e and explosion energy E SN ≈2.3×10 51 erg. The post-explosion anisotropies (pistons) reproduce the observed distributions of Fe and Si/ S if they had a total mass of ≈0.25 M e and a total kinetic energy of ≈1.5×10 50 erg. The pistons produce a spatial inversion of ejecta layers at the epoch of Cas A, leading to the Si/S-rich ejecta physically interior to the Fe-rich ejecta. The pistons are also responsible for the development of the bright rings of Si/S-rich material which form at the intersection between the reverse shock and the material accumulated around the pistons during their propagation. Our result supports the idea that the bulk of asymmetries observed in Cas A are intrinsic to the explosion.
The Astrophysical Journal, 2015
The emission of supernova remnants (SNRs) reflects the properties of both the progenitor supernov... more The emission of supernova remnants (SNRs) reflects the properties of both the progenitor supernovae (SNe) and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here, we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the SN. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15,000 after the SN. We demonstrated that the physical model reproducing the main observables of SN 1987A during the first 250 days of evolution also reproduces the X-ray emission of the subsequent expanding remnant, thus bridging the gap between SNe and SNRs. By comparing model results with observations, we constrained the explosion energy in the range 1.2-1.4 × 10 51 erg and the envelope mass in the range 15-17 M e. We found that the shape of X-ray lightcurves and spectra at early epochs (<15 years) reflects the structure of outer ejecta: our model reproduces the observations if the outermost ejecta have a post-explosion radial profile of density approximated by a power law with index α = −8. At later epochs, the shapes of X-ray lightcurves and spectra reflect the density structure of the nebula around SN 1987A. This enabled us to ascertain the origin of the multi-thermal X-ray emission, disentangle the imprint of the SN on the remnant emission from the effects of the remnant interaction with the environment, and constrain the pre-supernova structure of the nebula.
The so-called Super-AGB stars have initial mass between M_{up} (minimum initial mass above which ... more The so-called Super-AGB stars have initial mass between M_{up} (minimum initial mass above which C-burning ignites) and M_{mas} (minimum initial mass for the completion of all the nuclear burning phases leading to an iron-core collapse supernova). Thus these stars are massive enough to ignite carbon but, being unable to evolve through all nuclear burning stages, they end their life either
Super-AGB stars can conclude their evolution either as neon-oxygen white dwarfs or as electron-ca... more Super-AGB stars can conclude their evolution either as neon-oxygen white dwarfs or as electron-capture supernovae. We discuss the possible consequences of the existence of this "double final fate" in the self-enrichment of globular clusters and in the nucleosynthesis process of s-nuclei.
The Astrophysical Journal, 2012
Astronomy & Astrophysics, 2006
Using a new s-nucleosynthesis code, coupled with the stellar evolution code Star2003, we performe... more Using a new s-nucleosynthesis code, coupled with the stellar evolution code Star2003, we performed simulations to study the impact of the convection treatment on the s-process during core He-burning in a 25 M star (ZAMS mass) with an initial metallicity of Z = 0.02. Particular attention was devoted to the impact of the extent of overshooting on the s-process efficiency. The results show enhancements of about a factor 2−3 in s-process efficiency (measured as the average overproduction factor of the 6 s-only nuclear species with 60 < ∼ A < ∼ 90) with overshooting parameter values in the range 0.01−0.035, compared to results obtained with the same model but without overshooting. The impact of these results on the p-process model based on type II supernovae is discussed.
Astronomy & Astrophysics, 2010
Context. Many studies on the s-process and, more specifically, on the s-process weak component ha... more Context. Many studies on the s-process and, more specifically, on the s-process weak component have been performed so far, but a detailed scrutiny of the impact of the stellar evolution modeling uncertainties on the efficiency of this nucleosynthesis process is still missing. Aims. We analyze the role of convective overshooting on the production of s-nuclei in massive stars during their core He-burning phase. Methods. With the "post-processing" technique we explore the role of the convective overshooting on the production of s-nuclei in stellar models of different initial mass and metallicity (15 ≤ M ZAMS /M ≤ 25; 10 −4 ≤ Z ≤ 0.02), considering a range of values for the parameter f , which determines the overall efficiency of convective overshooting. Results. We find enhancements in the production of s-nuclei until a factor ∼6 (measured as the average overproduction factor of the 6 s-only nuclear species with 60 A 90) in all our models of different initial mass and metallicity with f in the range 0.01−0.035 (i.e. models with overshooting) compared to the production obtained with "no-overshooting" models (i.e. models with the same initial mass and metallicity, but f = 10 −5). Moreover the results indicate that the link between the overshooting parameter f and the s-process efficiency is essentially monotonic in all our models of different initial mass and metallicity. Also evident is the higher s-process efficiency when we progressively increase for a given f value both the mass of the models from 15 M to 25 M and the Z value from 10 −4 to 0.02. We also briefly discuss the possible consequences of these results for some open questions linked to the s-process weak component efficiency, as well as a "rule of thumb" to evaluate the impact of the convective overshooting on the yields of a generation of stars.
The 6Li(p,alpha )3He bare nucleus cross-section at astrophysical energies has been indirectly mea... more The 6Li(p,alpha )3He bare nucleus cross-section at astrophysical energies has been indirectly measured in the framework of the Trojan-Horse Method. This constitutes an important step to address the astrophysical problem of 6Li (and more generally of light elements) surface abundance in stars. The agreement between results from direct and indirect methods is discussed in the context of the surface lithium
Due to the role played by the light elements lithium, beryllium and boron as "probe" of stellar m... more Due to the role played by the light elements lithium, beryllium and boron as "probe" of stellar mixing phenomena, the (p, α) channel for the boron destruction at astrophysically relevant energies was investigated. The reactions 11 B(p, α) 8 Be and 10 B(p, α) 7 Be are the main channels for its burning in stellar interior at about T = 10 6 Kelvin. By means of the indirect Trojan Horse Method the astrophysical S(E)-factor was then extracted for both reactions.
arXiv (Cornell University), Mar 18, 2023
Monthly Notices of the Royal Astronomical Society
With the aim of improving our knowledge about their nature, we conduct a comparative study on a s... more 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 ∼0.5–15 foe, radii of ∼0.2–100 × 1012 cm, and ejected masses of ∼15–55 M⊙. Although the sample may be too small to draw any final conclusion, these results suggest that (i) SN 1987A-like objects have parameters at explosion covering a wide range of values; (ii) the main parameter determining their distribution is the explosion energy; and (iii) a high-mass (≳ 30 M⊙) and high-energy (≳ 10 foe) tail of events, linked to extended progenitors with radii at explosion ∼1013–1014 cm, challenge standard theor...
Monthly Notices of the Royal Astronomical Society
Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cx... more Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cxd and 2021aai are presented. SN 2020cxd was discovered 2 d after explosion at an absolute magnitude of Mr = −14.02 ± 0.21 mag, subsequently settling on a plateau which lasts for ∼120 d. Through the luminosity of the late light curve tail, we infer a synthesized 56Ni mass of (1.8 ± 0.5) × 10−3 M⊙. During the early evolutionary phases, optical spectra show a blue continuum ($T\, \gt 8000K)withbroadBalmerlinesdisplayingaPCygniprofile,whileatlaterphases,Caii,Feii,Scii,andBaiilinesdominatethespectra.Hydrodynamicalmodellingoftheobservablesyields8000 K) with broad Balmer lines displaying a P Cygni profile, while at later phases, Ca ii, Fe ii, Sc ii, and Ba ii lines dominate the spectra. Hydrodynamical modelling of the observables yields 8000K)withbroadBalmerlinesdisplayingaPCygniprofile,whileatlaterphases,Caii,Feii,Scii,andBaiilinesdominatethespectra.HydrodynamicalmodellingoftheobservablesyieldsR\, \simeq$ 575 R⊙ for the progenitor star, with Mej = 7.5 M⊙ and E,simeqE\, \simeqE,simeq 0.097 foe emitted during the explosion. This low-energy event originating from a low-mass progenitor star is compatible with both the explosion of a red supergiant (RSG) star and with an Electron Capture Supernova arising from a super asy...
Monthly Notices of the Royal Astronomical Society, 2020
In this work, we present photometric and spectroscopic data of the low-luminosity (LL) Type IIP s... more In this work, we present photometric and spectroscopic data of the low-luminosity (LL) Type IIP supernova (SN) 2018hwm. The object shows a faint (Mr = −15 mag) and very long (∼130 d) plateau, followed by a 2.7 mag drop in the r band to the radioactive tail. The first spectrum shows a blue continuum with narrow Balmer lines, while during the plateau the spectra show numerous metal lines, all with strong and narrow P-Cygni profiles. The expansion velocities are low, in the 1000–1400 km s−1 range. The nebular spectrum, dominated by H α in emission, reveals weak emission from [O i] and [Ca ii] doublets. The absolute light curve and spectra at different phases are similar to those of LL SNe IIP. We estimate that 0.002 M⊙ of 56Ni mass were ejected, through hydrodynamical simulations. The best fit of the model to the observed data is found for an extremely low explosion energy of 0.055 foe, a progenitor radius of 215 R⊙, and a final progenitor mass of 9–10 M⊙. Finally, we performed a model...
Monthly Notices of the Royal Astronomical Society
A deep survey of the Large Magellanic Cloud at ∼0.1–100 TeV photon energies with the Cherenkov Te... more A deep survey of the Large Magellanic Cloud at ∼0.1–100 TeV photon energies with the Cherenkov Telescope Array is planned. We assess the detection prospects based on a model for the emission of the galaxy, comprising the four known TeV emitters, mock populations of sources, and interstellar emission on galactic scales. We also assess the detectability of 30 Doradus and SN 1987A, and the constraints that can be derived on the nature of dark matter. The survey will allow for fine spectral studies of N 157B, N 132D, LMC P3, and 30 Doradus C, and half a dozen other sources should be revealed, mainly pulsar-powered objects. The remnant from SN 1987A could be detected if it produces cosmic-ray nuclei with a flat power-law spectrum at high energies, or with a steeper index 2.3–2.4 pending a flux increase by a factor of >3–4 over ∼2015–2035. Large-scale interstellar emission remains mostly out of reach of the survey if its >10 GeV spectrum has a soft photon index ∼2.7, but degree-scal...
We investigate the role played by initial clumping of ejecta and by efficient acceleration of cos... more We investigate the role played by initial clumping of ejecta and by efficient acceleration of cosmic rays (CRs) in determining the density structure of the post-shock region of a Type Ia supernova remnant (SNR) through detailed 3D MHD modeling. Our model describes the expansion of a SNR through a magnetized interstellar medium (ISM), including the initial clumping of ejecta and the effects on shock dynamics due to back-reaction of accelerated CRs. The model predictions are compared to the observations of SN 1006. We found that the back-reaction of accelerated CRs alone cannot reproduce the observed separation between the forward shock (FS) and the contact discontinuity (CD) unless the energy losses through CR acceleration and escape are very large and independent of the obliquity angle. On the contrary, the clumping of ejecta can naturally reproduce the observed small separation and the occurrence of protrusions observed in SN 1006, even without the need of accelerated CRs. We conclude that FS-CD separation is a probe of the ejecta structure at the time of explosion rather than a probe of the efficiency of CR acceleration in young SNRs.
Supernova remnats (SNRs) show a complex morphology characterized by an inhomogeneous spatial dist... more Supernova remnats (SNRs) show a complex morphology characterized by an inhomogeneous spatial distribution of ejecta, believed to reflect pristine structures and features of the progenitor supernova (SN) explosion. Filling the gap between SN explosions and their remnants is very important for a comprehension of the origin of present-day structure of ejecta in SNRs and to probe and constraint current models of SN explosions. The SNR Cassiopeia A (Cas A) is an attractive laboratory for studying the SNe-SNRs connection, being one of the best studied SNRs for which its 3D structure is known. We present a three-dimensional hydrodynamic model describing the evolution of Cas A from the immediate aftermath of the SN explosion to its expansion through the interstellar medium, taking into account the distribution of element abundances of the ejecta, the backreaction of accelerated cosmic rays at the shock front, and the deviations from equilibrium of ionizazion for the most important elements. We use the model to derive the physical parameters characterizing the SN explosion and reproducing the today morphology of Cas A
Super-AGB stars can conclude their evolution either as neon -oxygen white dwarfs or as electron-c... more Super-AGB stars can conclude their evolution either as neon -oxygen white dwarfs or as electron-capture supernovae. We discuss the po ssible consequences of the existence of this “double final fate” in the self-enrichment of globular clusters and in the nucleosynthesis process of s-nuclei.
The Astrophysical Journal, 2016
The remnants of core-collapse supernovae (SNe) have complex morphologies that may reflect asymmet... more The remnants of core-collapse supernovae (SNe) have complex morphologies that may reflect asymmetries and structures developed during the progenitor SN explosion. Here we investigate how the morphology of the supernova remnant Cassiopeia A (Cas A) reflects the characteristics of the progenitor SN with the aim of deriving the energies and masses of the post-explosion anisotropies responsible for the observed spatial distribution of Fe and Si/S. We model the evolution of Cas A from the immediate aftermath of the progenitor SN to the three-dimensional interaction of the remnant with the surrounding medium. The post-explosion structure of the ejecta is described by small-scale clumping of material and larger-scale anisotropies. The hydrodynamic multi-species simulations consider an appropriate post-explosion isotopic composition of the ejecta. The observed average expansion rate and shock velocities can be well reproduced by models with ejecta mass M ej ≈4M e and explosion energy E SN ≈2.3×10 51 erg. The post-explosion anisotropies (pistons) reproduce the observed distributions of Fe and Si/ S if they had a total mass of ≈0.25 M e and a total kinetic energy of ≈1.5×10 50 erg. The pistons produce a spatial inversion of ejecta layers at the epoch of Cas A, leading to the Si/S-rich ejecta physically interior to the Fe-rich ejecta. The pistons are also responsible for the development of the bright rings of Si/S-rich material which form at the intersection between the reverse shock and the material accumulated around the pistons during their propagation. Our result supports the idea that the bulk of asymmetries observed in Cas A are intrinsic to the explosion.
The Astrophysical Journal, 2015
The emission of supernova remnants (SNRs) reflects the properties of both the progenitor supernov... more The emission of supernova remnants (SNRs) reflects the properties of both the progenitor supernovae (SNe) and the surrounding environment. The complex morphology of the remnants, however, hampers the disentanglement of the two contributions. Here, we aim at identifying the imprint of SN 1987A on the X-ray emission of its remnant and at constraining the structure of the environment surrounding the SN. We performed high-resolution hydrodynamic simulations describing SN 1987A soon after the core-collapse and the following three-dimensional expansion of its remnant between days 1 and 15,000 after the SN. We demonstrated that the physical model reproducing the main observables of SN 1987A during the first 250 days of evolution also reproduces the X-ray emission of the subsequent expanding remnant, thus bridging the gap between SNe and SNRs. By comparing model results with observations, we constrained the explosion energy in the range 1.2-1.4 × 10 51 erg and the envelope mass in the range 15-17 M e. We found that the shape of X-ray lightcurves and spectra at early epochs (<15 years) reflects the structure of outer ejecta: our model reproduces the observations if the outermost ejecta have a post-explosion radial profile of density approximated by a power law with index α = −8. At later epochs, the shapes of X-ray lightcurves and spectra reflect the density structure of the nebula around SN 1987A. This enabled us to ascertain the origin of the multi-thermal X-ray emission, disentangle the imprint of the SN on the remnant emission from the effects of the remnant interaction with the environment, and constrain the pre-supernova structure of the nebula.
The so-called Super-AGB stars have initial mass between M_{up} (minimum initial mass above which ... more The so-called Super-AGB stars have initial mass between M_{up} (minimum initial mass above which C-burning ignites) and M_{mas} (minimum initial mass for the completion of all the nuclear burning phases leading to an iron-core collapse supernova). Thus these stars are massive enough to ignite carbon but, being unable to evolve through all nuclear burning stages, they end their life either
Super-AGB stars can conclude their evolution either as neon-oxygen white dwarfs or as electron-ca... more Super-AGB stars can conclude their evolution either as neon-oxygen white dwarfs or as electron-capture supernovae. We discuss the possible consequences of the existence of this "double final fate" in the self-enrichment of globular clusters and in the nucleosynthesis process of s-nuclei.
The Astrophysical Journal, 2012
Astronomy & Astrophysics, 2006
Using a new s-nucleosynthesis code, coupled with the stellar evolution code Star2003, we performe... more Using a new s-nucleosynthesis code, coupled with the stellar evolution code Star2003, we performed simulations to study the impact of the convection treatment on the s-process during core He-burning in a 25 M star (ZAMS mass) with an initial metallicity of Z = 0.02. Particular attention was devoted to the impact of the extent of overshooting on the s-process efficiency. The results show enhancements of about a factor 2−3 in s-process efficiency (measured as the average overproduction factor of the 6 s-only nuclear species with 60 < ∼ A < ∼ 90) with overshooting parameter values in the range 0.01−0.035, compared to results obtained with the same model but without overshooting. The impact of these results on the p-process model based on type II supernovae is discussed.
Astronomy & Astrophysics, 2010
Context. Many studies on the s-process and, more specifically, on the s-process weak component ha... more Context. Many studies on the s-process and, more specifically, on the s-process weak component have been performed so far, but a detailed scrutiny of the impact of the stellar evolution modeling uncertainties on the efficiency of this nucleosynthesis process is still missing. Aims. We analyze the role of convective overshooting on the production of s-nuclei in massive stars during their core He-burning phase. Methods. With the "post-processing" technique we explore the role of the convective overshooting on the production of s-nuclei in stellar models of different initial mass and metallicity (15 ≤ M ZAMS /M ≤ 25; 10 −4 ≤ Z ≤ 0.02), considering a range of values for the parameter f , which determines the overall efficiency of convective overshooting. Results. We find enhancements in the production of s-nuclei until a factor ∼6 (measured as the average overproduction factor of the 6 s-only nuclear species with 60 A 90) in all our models of different initial mass and metallicity with f in the range 0.01−0.035 (i.e. models with overshooting) compared to the production obtained with "no-overshooting" models (i.e. models with the same initial mass and metallicity, but f = 10 −5). Moreover the results indicate that the link between the overshooting parameter f and the s-process efficiency is essentially monotonic in all our models of different initial mass and metallicity. Also evident is the higher s-process efficiency when we progressively increase for a given f value both the mass of the models from 15 M to 25 M and the Z value from 10 −4 to 0.02. We also briefly discuss the possible consequences of these results for some open questions linked to the s-process weak component efficiency, as well as a "rule of thumb" to evaluate the impact of the convective overshooting on the yields of a generation of stars.
The 6Li(p,alpha )3He bare nucleus cross-section at astrophysical energies has been indirectly mea... more The 6Li(p,alpha )3He bare nucleus cross-section at astrophysical energies has been indirectly measured in the framework of the Trojan-Horse Method. This constitutes an important step to address the astrophysical problem of 6Li (and more generally of light elements) surface abundance in stars. The agreement between results from direct and indirect methods is discussed in the context of the surface lithium
Due to the role played by the light elements lithium, beryllium and boron as "probe" of stellar m... more Due to the role played by the light elements lithium, beryllium and boron as "probe" of stellar mixing phenomena, the (p, α) channel for the boron destruction at astrophysically relevant energies was investigated. The reactions 11 B(p, α) 8 Be and 10 B(p, α) 7 Be are the main channels for its burning in stellar interior at about T = 10 6 Kelvin. By means of the indirect Trojan Horse Method the astrophysical S(E)-factor was then extracted for both reactions.
arXiv (Cornell University), Mar 18, 2023
Monthly Notices of the Royal Astronomical Society
With the aim of improving our knowledge about their nature, we conduct a comparative study on a s... more 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 ∼0.5–15 foe, radii of ∼0.2–100 × 1012 cm, and ejected masses of ∼15–55 M⊙. Although the sample may be too small to draw any final conclusion, these results suggest that (i) SN 1987A-like objects have parameters at explosion covering a wide range of values; (ii) the main parameter determining their distribution is the explosion energy; and (iii) a high-mass (≳ 30 M⊙) and high-energy (≳ 10 foe) tail of events, linked to extended progenitors with radii at explosion ∼1013–1014 cm, challenge standard theor...
Monthly Notices of the Royal Astronomical Society
Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cx... more Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cxd and 2021aai are presented. SN 2020cxd was discovered 2 d after explosion at an absolute magnitude of Mr = −14.02 ± 0.21 mag, subsequently settling on a plateau which lasts for ∼120 d. Through the luminosity of the late light curve tail, we infer a synthesized 56Ni mass of (1.8 ± 0.5) × 10−3 M⊙. During the early evolutionary phases, optical spectra show a blue continuum ($T\, \gt 8000K)withbroadBalmerlinesdisplayingaPCygniprofile,whileatlaterphases,Caii,Feii,Scii,andBaiilinesdominatethespectra.Hydrodynamicalmodellingoftheobservablesyields8000 K) with broad Balmer lines displaying a P Cygni profile, while at later phases, Ca ii, Fe ii, Sc ii, and Ba ii lines dominate the spectra. Hydrodynamical modelling of the observables yields 8000K)withbroadBalmerlinesdisplayingaPCygniprofile,whileatlaterphases,Caii,Feii,Scii,andBaiilinesdominatethespectra.HydrodynamicalmodellingoftheobservablesyieldsR\, \simeq$ 575 R⊙ for the progenitor star, with Mej = 7.5 M⊙ and E,simeqE\, \simeqE,simeq 0.097 foe emitted during the explosion. This low-energy event originating from a low-mass progenitor star is compatible with both the explosion of a red supergiant (RSG) star and with an Electron Capture Supernova arising from a super asy...
Monthly Notices of the Royal Astronomical Society, 2020
In this work, we present photometric and spectroscopic data of the low-luminosity (LL) Type IIP s... more In this work, we present photometric and spectroscopic data of the low-luminosity (LL) Type IIP supernova (SN) 2018hwm. The object shows a faint (Mr = −15 mag) and very long (∼130 d) plateau, followed by a 2.7 mag drop in the r band to the radioactive tail. The first spectrum shows a blue continuum with narrow Balmer lines, while during the plateau the spectra show numerous metal lines, all with strong and narrow P-Cygni profiles. The expansion velocities are low, in the 1000–1400 km s−1 range. The nebular spectrum, dominated by H α in emission, reveals weak emission from [O i] and [Ca ii] doublets. The absolute light curve and spectra at different phases are similar to those of LL SNe IIP. We estimate that 0.002 M⊙ of 56Ni mass were ejected, through hydrodynamical simulations. The best fit of the model to the observed data is found for an extremely low explosion energy of 0.055 foe, a progenitor radius of 215 R⊙, and a final progenitor mass of 9–10 M⊙. Finally, we performed a model...