Nearby Core-collapse Supernovae Research Articles

A Metallicity Dependence on the Occurrence of Core-collapse Supernovae

Core-collapse supernovae (CCSNe) are widely accepted to be caused by the explosive death of massive stars with initial masses ≳8 M ⊙. There is, however, a comparatively poor understanding of how properties of the progenitors—mass, metallicity, multiplicity, rotation, etc.—manifest in the resultant CCSN population. Here, we present a minimally biased sample of nearby CCSNe from the All-Sky Automated Survey for Supernovae survey whose host galaxies were observed with integral-field spectroscopy using MUSE at the Very Large Telescope. This data set allows us to analyze the explosion sites of CCSNe within the context of global star formation properties across the host galaxies. We show that the CCSN explosion site oxygen abundance distribution is offset to lower values than the overall H ii region abundance distribution within the host galaxies. We further split the sample at dex and show that within the subsample of low-metallicity host galaxies, the CCSNe unbiasedly trace the star formation with respect to oxygen abundance, while for the subsample of higher-metallicity host galaxies, they preferentially occur in lower-abundance star-forming regions. We estimate the occurrence of CCSNe as a function of oxygen abundance per unit star formation and show that there is a strong decrease as abundance increases. Such a strong and quantified metallicity dependence on CCSN production has not been shown before. Finally, we discuss possible explanations for our result and show that each of these has strong implications not only for our understanding of CCSNe and massive star evolution but also for star formation and galaxy evolution.

Early Hard X-Rays from the Nearby Core-collapse Supernova SN 2023ixf

We present NuSTAR observations of the nearby SN 2023ixf in M101 (d = 6.9 Mpc) that provide the earliest hard X-ray detection of a nonrelativistic stellar explosion to date at δ t ≈ 4 days and δ t ≈ 11 days. The spectra are well described by a hot thermal bremsstrahlung continuum with T > 25 keV shining through a thick neutral medium with a neutral hydrogen column that decreases with time (initial N Hint = 2.6 × 1023 cm−2). A prominent neutral Fe Kα emission line is clearly detected, similar to other strongly interacting supernovae (SNe) such as SN 2010jl. The rapidly decreasing intrinsic absorption with time suggests the presence of a dense but confined circumstellar medium (CSM). The absorbed broadband X-ray luminosity (0.3–79 keV) is L X ≈ 2.5 × 1040 erg s−1 during both epochs, with the increase in overall X-ray flux related to the decrease in the absorbing column. Interpreting these observations in the context of thermal bremsstrahlung radiation originating from the interaction of the SN shock with a dense medium we infer large particle densities in excess of n CSM ≈ 4 × 108 cm−3 at r < 1015 cm, corresponding to an enhanced progenitor mass-loss rate of M ⊙ yr−1 for an assumed wind velocity of v w = 50 km s−1.

Precursors of Supernovae from Mass Eruption: Prospects for Early Warning of Nearby Core-collapse Supernovae

Recent observations of a large fraction of Type II supernovae (SNe) show traces of dense circumstellar medium (CSM) very close to the progenitor star. If this CSM is created by eruptive mass loss several months before core collapse, the eruption itself may be visible as a precursor, helpful as an early warning of a near-future SN. Using radiation hydrodynamical simulations based on the open-source code CHIPS, we theoretically model the emission from the mass eruption of a red supergiant star. We find that for a modest mass eruption the luminosity is typically on the order of 1039 erg s−1, can last as long as hundreds of days until the star explodes, and is mainly bright in the infrared (from −9 to −11 mag around peak). We discuss observational strategies to find these signatures from Galactic and local Type II SNe.

Number of stars in the Sun’s birth cluster revisited

The Sun is thought to have been formed within a star cluster. The coexistence of 26Al-rich and 26Al-poor calcium–aluminum-rich inclusions indicates that a direct injection of 26Al-rich materials from a nearby core-collapse supernova would be expected to occur in the first 105 years of the existence of the Solar System. Therefore, at least one core-collapse supernova ought to occur within the duration of star formation in the Sun’s birth cluster. Here, we revisit the number of stars in the Sun’s birth cluster from the point of view of the probability of experiencing at least one core-collapse supernova within the finite duration of star formation within the birth cluster. We find that the number of stars in the birth cluster may be significantly greater than that previously considered, depending on the duration of star formation.

Evidence for Enrichment of Niobium-92 in the Outer Protosolar Disk

The short-lived radionuclide, niobium-92 (92Nb), has been used to estimate the site of nucleosynthesis for p-nuclei and the timing of planetary differentiation, assuming that it was uniformly distributed in the early solar system. Here, we present the internal niobium–zirconium (Nb–Zr) isochron dating of Northwest Africa (NWA) 6704, an achondrite thought to form in the outer protosolar disk due to nucleosynthetic isotope similarities with carbonaceous chondrites. The isochron defines an initial 92Nb/93Nb ratio of (2.72 ± 0.25) × 10−5 at the NWA 6704 formation, 4562.76 ± 0.30 million years ago. This corresponds to a 92Nb/93Nb ratio of (2.96 ± 0.27) × 10−5 at the time of solar system formation, which is ∼80% higher than the values obtained from meteorites formed in the inner disk. The results suggest that a significant proportion of the solar 92Nb was produced by a nearby core-collapse supernova (CCSN) and that the outer disk was more enriched in CCSN ejecta, which could account for the heterogeneity of short-lived 26Al and nucleosynthetic stable-isotope anomalies across the disk. We propose that NWA 6704 serves as the best anchor for mapping relative Nb–Zr ages of objects in the outer solar system onto the absolute timescale.

Supernova neutrinos as a precise probe of nuclear neutron skin

A precise and model-independent determination of the neutron distribution radius ${R}_{n}$ and thus the neutron skin thickness ${R}_{\mathrm{skin}}$ of atomic nuclei is of fundamental importance in nuclear physics, particle physics, and astrophysics but remains a big challenge in terrestrial labs. We argue that the nearby core-collapse supernova (CCSN) in our Galaxy may render a neutrino flux with unprecedentedly high luminosity, offering the perfect opportunity to determine the ${R}_{n}$ and ${R}_{\mathrm{skin}}$ through the coherent elastic neutrino-nucleus scattering ($\mathrm{CE}\ensuremath{\nu}\mathrm{NS}$). We evaluate the potential of determining the ${R}_{n}$ of lead (Pb) via $\mathrm{CE}\ensuremath{\nu}\mathrm{NS}$ with the nearby CCSN neutrinos in the RES-NOVA project which is designed to hunt CCSN neutrinos using an array of archaeological Pb based cryogenic detectors. We find that an ultimate precision of $\ensuremath{\sim}0.1%$ for the ${R}_{n}$ ($\ensuremath{\sim}0.006\text{ }\text{ }\mathrm{fm}$ for the ${R}_{\mathrm{skin}}$) of Pb can be achieved via RES-NOVA in the most optimistic case that the CCSN explosion were to occur at a distance of $\ensuremath{\sim}1\text{ }\text{ }\mathrm{kpc}$ from the Earth.

The disappearances of six supernova progenitors

ABSTRACT As part of a larger completed Hubble Space Telescope (HST) Snapshot program, we observed the sites of six nearby core-collapse supernovae (SNe) at high spatial resolution: SN 2012A, SN 2013ej, SN 2016gkg, SN 2017eaw, SN 2018zd, and SN 2018aoq. These observations were all conducted at sufficiently late times in each SN’s evolution to demonstrate that the massive-star progenitor candidate identified in each case in pre-explosion imaging data had indeed vanished and was therefore most likely the actual progenitor. However, we have determined for SN 2016gkg that the progenitor candidate was most likely a blend of two objects: the progenitor, which itself has likely vanished, and another closely neighbouring star. We thus provide a revised estimate of that progenitor’s properties: a binary system with a hydrogen-stripped primary star at explosion with effective temperature ≈6300–7900 K, bolometric luminosity ≈104.65 L⊙, radius ≈118–154 R⊙, and initial mass 9.5–11 M⊙. Utilizing late-time additional archival HST data nearly contemporaneous with our Snapshots, we also show that SN 2017eaw had a luminous ultraviolet excess, which is best explained as a result of ongoing interaction of the SN shock with pre-existing circumstellar matter. We offer the caveat, particularly in the case of SN 2013ej, that obscuration from SN dust may be compromising our conclusions. This sample adds to the growing list of confirmed or likely core-collapse SN progenitors.

Determining the Core Structure and Nuclear Equation of State of Rotating Core-collapse Supernovae with Gravitational Waves by Convolutional Neural Networks

Detecting gravitational waves from a nearby core-collapse supernova would place meaningful constraints on the supernova engine and nuclear equation of state. Here we use convolutional neural network models to identify the core rotational rates, rotation length scales, and the nuclear equation of state (EoS), using the 1824 waveforms from Richers et al. for a 12 solar mass progenitor. A high prediction accuracy for the classifications of the rotation length scales (93%) and the rotational rates (95%) can be achieved using the gravitational-wave signals from −10 to 6 ms core bounce. By including an additional 48 ms signal during the prompt convection phase, we could achieve an accuracy of 96% in the classification of the four main EoS groups. By combining the three models above, we could correctly predict the core rotational rates, rotation length scales, and the EoS at the same time with an accuracy of more than 85%. Finally, applying a transfer-learning method for an additional 74 waveforms from FLASH simulations, we show that our model using Richers’ waveforms could successfully predict the rotational rates from Pan’s waveforms even for a continuous value with mean absolute errors of 0.32 rad s−1 only. These results demonstrate the much broader parameter regimes to which our model can be applied to identify core-collapse supernova events through gravitational-wave signals.

Inferring astrophysical parameters of core-collapse supernovae from their gravitational-wave emission

Nearby core-collapse supernovae (CCSNe) are powerful multimessenger sources for gravitational-wave, neutrino, and electromagnetic telescopes as they emit gravitational waves in the ideal frequency band for ground based detectors. Once a CCSN gravitational-wave signal is detected, we will need to determine the parameters of the signal and understand how those parameters relate to the source's explosion, progenitor, and remnant properties. This is a challenge due to the stochastic nature of CCSN explosions, which is imprinted on their time series gravitational waveforms. In this paper, we perform Bayesian parameter estimation of CCSN signals using an asymmetric chirplet signal model to represent the dominant high-frequency mode observed in spectrograms of CCSN gravitational-wave signals. We use design sensitivity Advanced LIGO noise and CCSN waveforms from four different hydrodynamical supernova simulations with a range of different progenitor stars. We determine how well our model can reconstruct time-frequency images of the emission modes and show how well we can determine parameters of the signal such as the frequency, amplitude, and duration. We show how the parameters of our signal model may allow us to place constraints on the protoneutron star mass and radius, the turbulent kinetic energy onto the protoneutron star, and the time of shock revival.

Core-collapse, superluminous, and gamma-ray burst supernova host galaxy populations at low redshift: the importance of dwarf and starbursting galaxies

ABSTRACT We present a comprehensive study of an unbiased sample of 150 nearby (median redshift, z = 0.014) core-collapse supernova (CCSN) host galaxies drawn from the All-Sky Automated Survey for Supernovae (ASAS-SN) for direct comparison to the nearest long-duration gamma-ray burst (LGRB) and superluminous supernova (SLSN) hosts. We use public imaging surveys to gather multiwavelength photometry for all CCSN host galaxies and fit their spectral energy distributions (SEDs) to derive stellar masses and integrated star formation rates (SFRs). CCSNe populate galaxies across a wide range of stellar masses, from blue and compact dwarf galaxies to large spiral galaxies. We find 33$^{+4}_{-4}$ per cent of CCSNe are in dwarf galaxies (M* &amp;lt; 109 M⊙) and 2$^{+2}_{-1}$ per cent are in dwarf starburst galaxies [specific star formation rate (sSFR) &amp;gt; 10−8 yr−1]. We reanalyse low-redshift SLSN and LGRB hosts from the literature (out to z &amp;lt; 0.3) in a homogeneous way and compare against the CCSN host sample. The relative SLSN to CCSN supernova rate is increased in low-mass galaxies and at high sSFRs. These parameters are strongly covariant and we cannot break the degeneracy between them with our current sample, although there is some evidence that both factors may play a role. Larger unbiased samples of CCSNe from projects such as ZTF and LSST will be needed to determine whether host-galaxy mass (a proxy for metallicity) or sSFR (a proxy for star formation intensity and potential IMF variation) is more fundamental in driving the preference for SLSNe and LGRBs in unusual galaxy environments.

Constraining Properties of the Next Nearby Core-collapse Supernova with Multimessenger Signals

Abstract With the advent of modern neutrino and gravitational wave (GW) detectors, the promise of multimessenger detections of the next galactic core-collapse supernova (CCSN) has become very real. Such detections will give insight into the CCSN mechanism and the structure of the progenitor star, and may resolve longstanding questions in fundamental physics. In order to properly interpret these detections, a thorough understanding of the landscape of possible CCSN events, and their multimessenger signals, is needed. We present detailed predictions of neutrino and GW signals from 1D simulations of stellar core collapse, spanning the landscape of core-collapse progenitors from 9 to 120 M ⊙. In order to achieve explosions in 1D, we use the Supernova Turbulence In Reduced-dimensionality model, which includes the effects of turbulence and convection in 1D supernova simulations to mimic the 3D explosion mechanism. We study the GW emission from the 1D simulations using an astroseismology analysis of the protoneutron star. We find that the neutrino and GW signals are strongly correlated with the structure of the progenitor star and remnant compact object. Using these correlations, future detections of the first few seconds of neutrino and GW emission from a galactic CCSN may be able to provide constraints on stellar evolution independent of preexplosion imaging and the mass of the compact object remnant prior to fallback accretion.

The SPIRITS Sample of Luminous Infrared Transients: Uncovering Hidden Supernovae and Dusty Stellar Outbursts in Nearby Galaxies*

Abstract We present a systematic study of the most luminous (M IR [Vega magnitudes] brighter than −14) infrared (IR) transients discovered by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) between 2014 and 2018 in nearby galaxies (D &lt; 35 Mpc). The sample consists of nine events that span peak IR luminosities of M [4.5],peak between −14 and −18.2, show IR colors between 0.2 &lt; ([3.6]–[4.5]) &lt; 3.0, and fade on timescales between 55 days &lt; t fade &lt; 480 days. The two reddest events (A V &gt; 12) show multiple, luminous IR outbursts over several years and have directly detected, massive progenitors in archival imaging. With analyses of extensive, multiwavelength follow-up, we suggest the following possible classifications: five obscured core-collapse supernovae (CCSNe), two erupting massive stars, one luminous red nova, and one intermediate-luminosity red transient. We define a control sample of all optically discovered transients recovered in SPIRITS galaxies and satisfying the same selection criteria. The control sample consists of eight CCSNe and one Type Iax SN. We find that 7 of the 13 CCSNe in the SPIRITS sample have lower bounds on their extinction of 2 &lt; A V &lt; 8. We estimate a nominal fraction of CCSNe in nearby galaxies that are missed by optical surveys as high as (90% confidence). This study suggests that a significant fraction of CCSNe may be heavily obscured by dust and therefore undercounted in the census of nearby CCSNe from optical searches.

Prospects for multi-messenger extended emission from core-collapse supernovae in the Local Universe

Multi-messenger emissions from SN1987A and GW170817/GRB170817A suggest a Universe rife with multi-messenger transients associated with black holes and neutron stars. For LIGO-Virgo, soon to be joined by KAGRA, these observations promise unprecedented opportunities to probe the central engines of core-collapse supernovae (CC-SNe) and gamma-ray bursts. Compared to neutron stars, central engines powered by black hole-disk or torus systems may be of particular interest to multi-messenger observations by the relatively large energy reservoir $E_J$ of angular momentum, up to 29\% of total mass in the Kerr metric. These central engines are expected from relatively massive stellar progenitors and compact binary coalescence involving a neutron star. We review prospects of multi-messenger emission by catalytic conversion of $E_J$ by a non-axisymmetric disk or torus. Observational support for this radiation process is found in a recent identification of ${\cal E}\simeq (3.5\pm1)\%M_\odot c^2$ in Extended Emission to GW170817 at a significance of 4.2\,$\sigma$ concurrent with GRB170817A. A prospect on similar emissions from nearby CC-SNe justifies the need for all-sky blind searches of long duration bursts by heterogeneous computing.

A nearby recent supernova that ejected the runaway star ζ Oph, the pulsar PSR B1706−16, and 60Fe found on Earth

ABSTRACT The detection of ∼1.5–3.2 Myr old 60Fe on Earth indicates recent nearby core-collapse supernovae. For supernovae in multiple stars, the primary stars may become neutron stars, while former companions may become unbound and become runaway stars. We wrote software for tracing back the space motion of runaway and neutron stars to young associations of massive stars. We apply it here to the nearby young Scorpius–Centaurus–Lupus groups, all known runaway stars possibly coming from there, and all 400 neutron stars with known transverse velocity. We find kinematic evidence that the runaway ζ Oph and the radio pulsar PSR B1706−16 were released by a supernova in a binary 1.78 ± 0.21 Myr ago at 107 ± 4 pc distance (for pulsar radial velocity 260 ± 43 km s−1); association age and flight time determine the progenitor mass (16–18 M⊙), which can constrain supernova nucleosynthesis yields and 60Fe uptake on Earth. In addition, we notice that the only high-mass X-ray binary in Scorpius–Centaurus–Lupus (1H11255−567 with μ1 and μ2 Cru) may include a neutron star formed in another SN, up to ∼1.8 Myr ago at 89−112 pc, i.e. also yielding 60Fe detectable on Earth. Our scenario links 60Fe found on Earth to one or two individual supernovae in multiple stars.

Core-collapse supernovae ages and metallicities from emission-line diagnostics of nearby stellar populations

Massive stars are the main objects that illuminate H II regions and they evolve quickly to end their lives in core-collapse supernovae (CCSNe). Thus it is important to investigate the association between CCSNe and H II regions. In this paper, we present emission line diagnostics of the stellar populations around nearby CCSNe, that include their host H II regions, from the PMAS/PPAK Integral-field Supernova hosts COmpilation (PISCO). We then use BPASS stellar population models to determine the age, metallicity and gas parameters for H II regions associated with CCSNe, contrasting models that consider either single star evolution alone or incorporate interacting binaries. We find binary-star models, that allow for ionizing photon loss, provide a more realistic fit to the observed CCSN hosts with metallicities that are closer to those derived from the oxygen abundance in O3N2. We also find that type II and type Ibc SNe arise from progenitor stars of similar age, mostly from 7 to 45 Myr, which corresponds to stars with masses < 20 solar mass . However these two types SNe have little preference in their host environment metallicity measured by oxygen abundance or in progenitor initial mass. We note however that at lower metallicities supernovae are more likely to be of type II.

Towards asteroseismology of core-collapse supernovae with gravitational wave observations – II. Inclusion of space–time perturbations

Improvements in ground-based, advanced gravitational wave (GW) detectors may allow in the near future to observe the GW signal of a nearby core-collapse supernova. For the most common type of progenitors, likely with slowly rotating cores, the dominant GW emission mechanisms are the post-bounce oscillations of the proto-neutron star (PNS) before the explosion. We present a new procedure to compute the eigenmodes of the system formed by the PNS and the stalled accretion shock in general relativity including spacetime perturbations. The new method improves on previous results by accounting for perturbations of both the lapse function and the conformal factor. We apply our analysis to two numerical core-collapse simulations and show that our improved method is able to obtain eigenfrequencies that accurately match the features observed in the GW signal and to predict the qualitative behaviour of quasi-radial oscillations. Our analysis is possible thanks to a newly developed algorithm to classify the computed eigenmodes in different classes (f-, p-, and g-modes), improving previous results which suffered from misclassification issues. We find that most of the GW energy is stored in the lowest order eigenmodes, in particular in the $^2g_1$ mode and in the $^2f$ mode. Our results also suggest that a low-frequency component of the GW signal attributed in previous works to the characteristic frequency of the Standing Accretion Shock Instability should be identified as the fundamental quadrupolar f-mode. We also develop a formalism to estimate the contribution of quasi-radial ($l=0$) modes to the quadrupolar component of the GW emission in the case of a deformed background, with application to rapidly rotating cores. This work provides further support for asteroseismology of core-collapse supernovae and the inference of PNS properties based on GW observations.

Ruthenium Isotope Composition of Allende Refractory Metal Nuggets

Abstract Refractory metal nuggets (RMNs) are among the first solids formed in the nascent solar system. They contain high abundances of refractory metals like Re, Os, W, Ir, Ru, and Pt. The isotopic compositions of these elements bear testimony to the stellar sources that contributed to the nucleosynthetic makeup of our solar system. We report the first high-precision Ru isotope data for a bulk RMN sample prepared from the Allende meteorite. The RMNs display well-resolved mass-independent anomalies with positive anomalies for 96Ru, 98Ru, 100Ru, 102Ru, and 104Ru. These are best explained by a deficit in r-process combined with a slight deficit in p-process nuclides. This finding stands in stark contrast to the s-process deficit isotopic patterns observed for Allende Ca–Al-rich inclusions (CAIs), bulk Allende, and other bulk meteorites. The contrasting r-, p-deficit versus s-deficit Ru isotopic signatures observed between RMNs and CAIs is surprising, given that CAIs are assumed to be a major host phase of RMNs. One way to explain the s-deficit patterns observed for CAIs and bulk meteorites is that r- and p-process Ru nuclides were added to the solar nebula after RMN formation and prior to the formation of CAIs and the accretion of meteorite parent bodies. A possible source may have been a nearby core-collapse supernova that injected freshly synthesized r- and p-process nuclides into the nascent solar system. The injection of such r- and p-enriched matter represents an alternative mechanism to account for the s-process variability presented by CAIs and bulk carbonaceous meteorites.

Prospects for detecting eV-scale sterile neutrinos from a galactic supernova

Future neutrino detectors will obtain high-statistics data from a nearby core-collapse supernova. We study the mixing with eV-mass sterile neutrinos in a supernova environment and its effects on the active neutrino fluxes as detected by Hyper-Kamiokande and IceCube. Using a Markov Chain Monte Carlo analysis, we make projections for how accurately these experiments will measure the active-sterile mixing angle θs given that there are substantial uncertainties on the expected luminosity and spectrum of active neutrinos from a galactic supernova burst. We find that Hyper-Kamiokande can reconstruct the sterile neutrino mixing and mass in many different situations, provided the neutrino luminosity of the supernova is known precisely. Crucially, we identify a degeneracy between the mixing angle and the overall neutrino luminosity of the supernova. This means that it will only be possible to determine the luminosity if the presence of sterile neutrinos with θs ≳ 0.1̂ can be ruled out independently. We discuss ways in which this degeneracy may be broken in the future.

Constraints for the Progenitor Masses of Historic Core-collapse Supernovae

Abstract We age-date the stellar populations associated with 12 historic nearby core-collapse supernovae (CCSNe) and two supernova impostors; from these ages, we infer their initial masses and associated uncertainties. To do this, we have obtained new Hubble Space Telescope imaging covering these CCSNe. Using these images, we measure resolved stellar photometry for the stars surrounding the locations of the SNe. We then fit the color–magnitude distributions of this photometry with stellar evolution models to determine the ages of any young existing populations present. From these age distributions, we infer the most likely progenitor masses for all of the SNe in our sample. We find ages between 4 and 50 Myr, corresponding to masses from 7.5 to 59 solar masses. There were no SNe that lacked a local young population. Our sample contains four SNe Ib/c; their masses have a wide range of values, suggesting that the progenitors of stripped-envelope SNe are binary systems. Both impostors have masses constrained to be ≲7.5 solar masses. In cases with precursor imaging measurements, we find that age-dating and precursor imaging give consistent progenitor masses. This consistency implies that, although the uncertainties for each technique are significantly different, the results of both are reliable to the measured uncertainties. We combine these new measurements with those from our previous work and find that the distribution of 25 core-collapse SNe progenitor masses is consistent with a standard Salpeter power-law mass function, no upper mass cutoff, and an assumed minimum mass for core-collapse of 7.5 M ⊙. The distribution is consistent with a minimum mass &lt;9.5 M ⊙.

The disappearance of the progenitor of SN 2012aw in late-time imaging

Abstract We present new late-time near-infrared imaging of the site of the nearby core-collapse supernova SN 2012aw, confirming the disappearance of the point source identified by Fraser et al. and Van Dyk et al. as a candidate progenitor in both J and Ks filters. We remeasure the progenitor photometry, and find that both the J and Ks magnitudes of the source are consistent with those quoted in the literature. We also recover a marginal detection of the progenitor in H-band, for which we measure H = 19.67 ± 0.40 mag. Comparing the luminosity of the progenitor to stellar evolutionary models, SN 2012aw appears to have resulted from the explosion of a 12.5 ± 1.5 M⊙ red supergiant.