Supernova SN1987A Research Articles

Supersonic velocities in noncommutative acoustic black holes

In this paper we derive Schwarzschild and Kerr - like noncommutative acoustic black hole metrics in the (3+1)-dimensional noncommutative Abelian Higgs model. We have found that the changing in the Hawking temperature T_H due to spacetime noncommutativity account for supersonic velocities and analogously may also account for superluminal particles in the general form (v-c)/c=\Delta T_H/8T_H. Assuming this form is also valid for gravitational black holes and particle physics, we have found that for \Delta T_H about the heaviest muon neutrino mass and T_H about proton mass gives 2.12\times 10-5 which agrees with the recent OPERA experiments. We also consider the Hawking temperature in terms of surface gravity to address the issue of background influence in the neutrino superluminality to show that our investigations also agree with supernova SN1987A measurements.

Superluminal neutrinos from Lorentz-violating dimension-5 operators

We consider Lorentz- and CPT-violating dimension-5 operators to address the issue of superluminal neutrinos recently pointed out in OPERA experiments. We assume these operators in the photon and neutrino sectors to be coupled to Lorentz-violating backgrounds in a preferred frame defined by a time-like direction. We show that such operators can produce a curve with OPERA’s slope that fits OPERA, MINOS and supernova SN1987a data.

On the possibility of superluminal neutrino propagation

We analyze the possibility of superluminal neutrino propagation δv≡(v−c)/c>0 as indicated by OPERA data, in view of previous phenomenological constraints from supernova SN1987a and gravitational Čerenkov radiation. We argue that the SN1987a data rule out δv∼(Eν/MN)N for N⩽2 and exclude, in particular, a Lorentz-invariant interpretation in terms of a ‘conventional’ tachyonic neutrino. We present two toy Lorentz-violating theoretical models, one a Lifshitz-type fermion model with superluminality depending quadratically on energy, and the other a Lorentz-violating modification of a massless Abelian gauge theory with axial–vector couplings to fermions. In the presence of an appropriate background field, fermions may propagate superluminally or subluminally, depending inversely on energy, and on direction. Reconciling OPERA with SN1987a would require this background field to depend on location.

X-ray illumination of the ejecta of supernova 1987A

When a massive star explodes as a supernova, substantial amounts of radioactive elements--primarily (56)Ni, (57)Ni and (44)Ti--are produced. After the initial flash of light from shock heating, the fading light emitted by the supernova is due to the decay of these elements. However, after decades, the energy powering a supernova remnant comes from the shock interaction between the ejecta and the surrounding medium. The transition to this phase has hitherto not been observed: supernovae occur too infrequently in the Milky Way to provide a young example, and extragalactic supernovae are generally too faint and too small. Here we report observations that show this transition in the supernova SN 1987A in the Large Magellanic Cloud. From 1994 to 2001, the ejecta faded owing to radioactive decay of (44)Ti as predicted. Then the flux started to increase, more than doubling by the end of 2009. We show that this increase is the result of heat deposited by X-rays produced as the ejecta interacts with the surrounding material. In time, the X-rays will penetrate farther into the ejecta, enabling us to analyse the structure and chemistry of the vanished star.

New constraints for heavy axion-like particles from supernovae

We derive new constraints on the coupling of heavy pseudoscalar (axion-like) particles to photons, based on the gamma ray flux expected from the decay of these particles into photons. After being produced in the supernova core, these heavy axion-like particles would escape and a fraction of them would decay into photons before reaching the Earth. We have calculated the expected flux on Earth of these photons from the supernovae SN 1987A and Cassiopeia A and compared our results to data from the Fermi Large Area Telescope. This analysis provides strong constraints on the parameter space for axion-like particles. For a particle mass of 100 MeV, we find that the Peccei-Quinn constant, fa, must be greater than about 1015 GeV. Alternatively, for fa = 1012 GeV, we exclude the mass region between approximately 100 eV and 1 GeV.

More Supernova Surprises

Spectroscopic observations of the supernova SN1987A are providing a new window into high-energy shock physics.

Massive binary evolution

Understanding the evolution of massive binaries is essential for understanding many observed classes of stellar systems, ranging from Algols to X-ray binaries, recycled pulsars, double-neutron-star systems and quite possibly gamma-ray burst sources. Here recent progress and some of the main remaining uncertainties are being reviewed, particularly emphasizing stellar mergers and their possible implications for supernovae like SN 1987A, Thorne–Żytkow objects and η Car-like eruptions. It is shown how binary evolution can affect both the envelope and the core structure of a massive star, explaining – at least in part – the observed diversity of core-collapse supernovae and potentially producing different kick distributions for systems in binaries. Various ideas linking gamma-ray bursts to massive binaries are also being discussed.

A massive hypergiant star as the progenitor of the supernova SN 2005gl

Our understanding of the evolution of massive stars before their final explosions as supernovae is incomplete, from both an observational and a theoretical standpoint. A key missing piece in the supernova puzzle is the difficulty of identifying and studying progenitor stars. In only a single case-that of supernova SN 1987A in the Large Magellanic Cloud-has a star been detected at the supernova location before the explosion, and been subsequently shown to have vanished after the supernova event. The progenitor of SN 1987A was a blue supergiant, which required a rethink of stellar evolution models. The progenitor of supernova SN 2005gl was proposed to be an extremely luminous object, but the association was not robustly established (it was not even clear that the putative progenitor was a single luminous star). Here we report that the previously proposed object was indeed the progenitor star of SN 2005gl. This very massive star was likely a luminous blue variable that standard stellar evolution predicts should not have exploded in that state.

Bounds on the parameter of noncommutativity from supernova SN1987A

We consider supernova SN1987A to find bounds on the parameter of noncommutativity, {theta}{sub {mu}}{sub {nu}}. The right-handed neutrino in the noncommutative standard model (NCSM) can directly couple to the photon and the Z-gauge boson. Therefore the observed flux of neutrinos from SN1987A can constrain the strength of the new couplings in the NCSM. We obtain two bounds on the NC-parameter, {lambda}{sub NC}=1/{radical}(|){theta}|, with respect to escaping or trapping of the right-handed neutrinos inside the supernova which are {lambda}{sub NC} > or approx. 3.7 TeV or {lambda}{sub NC} or approx. 3.7 TeV is more stringent than the other bounds obtained from LEP and LHC considerations. Furthermore, since NC calculations are perturbative and are correct only up to the energy scale of the NC system < or approx. {lambda}{sub NC}, then thesemore » bounds (which are obtained from the energy scale and considerably less than the energy scale of LEP and LHC) are more reliable.« less

Supernova detection

The detection of supernova neutrinos is reviewed, focusing on the current status of experiments to detect supernova burst neutrinos and supernova relic neutrinos. The capabilities of each detector currently operating and in development are assessed and the likely neutrino yield for a future supernova is estimated. It is expected that much more information will be obtained if a supernova burst were to occur in our Galaxy than was obtained for supernova SN1987A. The detection of supernova relic neutrinos is considered and it is concluded that a large volume detector with a neutron tagging technique is necessary.

SN 1987A — HISTORICAL VIEW ABOUT REGISTRATION OF THE NEUTRINO SIGNAL WITH BAKSAN, KAMIOKANDE II AND IMB DETECTORS

The detection of neutrinos from SN 1987A opened a new era in neutrino astrophysics in the last century. We present a historical view about registration of the neutrino signal from supernova SN 1987A in the Large Magellanic Cloud by the BAKSAN liquid scintillator detector and by the two water Cherenkov detectors — Kamiokande-II and IMB. All three detectors observed a total neutrino signal of 24 events at 7:35 UT 23 February, 1987. I will concentrate mostly about the BAKSAN supernova group analysis of the neutrino signal, which was already done in the years 1987 and 1988. The results of this analysis (determination of average properties of the neutrino signal: the total energy of neutrino emission, the effective neutrino temperature, the total luminosity of the neutrino signal, duration of the neutrino burst) are presented. The common analysis of all three detectors shows that these 'parameters' have good agreement with the general theoretical description of explosions of supernovae. The analysis shows that the inclusion of the BAKSAN data is very important for the understanding of the SN87A event. The latest results of 20 years of observation of our Galaxy by the BAKSAN scintillation telescope show that the upper limit of the mean frequency of gravitational collapses is &lt;0.13 yr-1 at a 90% confidence level.

Flavour in intersecting brane models and bounds on the string scale

We study flavour issues in non-supersymmetric intersecting brane models. Specifically, the purpose of the present paper is twofold: (i) to determine whether realistic flavour structures can be obtained in these models, and (ii) to establish whether the non-supersymmetric models address the gauge hierarchy problem. To this end, we find that realistic flavour structures, although absent at tree level, can arise even in the simplest models after effects of 4 fermion instanton-induced operators and radiative corrections have been taken into account. On the other hand, our analysis of flavour changing neutral currents (FCNC), electric dipole moments (EDM), supernova SN1987A and other constraints shows that the string scale has to be rather high, 10 4 TeV. This implies that non-supersymmetric intersecting brane models face a severe finetuning problem. Finally, we comment on how non-trivial flavour structures can arise in supersymmetric models.

X-Ray Triple Rings around the M87 Jets in the Central Virgo Cluster

The Chandra X-ray data of the central Virgo Cluster are reexamined to reveal a triple-ring structure around the galaxy M87, reminiscent of the spectacular triple-ring pattern of the supernova SN 1987A in the Large Magellanic Cloud. In the sky plane, the two apparent smaller ellipses are roughly aligned along the M87 jets; the larger ring centers at the M87 nucleus and is likely a circle roughly perpendicular to the M87 jet. Certain similarities of these two triple-ring structures might hint at similar processes that operate in these two systems with entirely different sizes and mass scales. We suspect that a major merging event of two galaxies with nuclear supermassive black holes (SMBHs) might create such a triple-ring structure and drove acoustic and internal gravity waves far and near. The M87 jets are perhaps powered by a spinning SMBH resulting from this catastrophic merging event.

High‐Resolution Mid‐infrared Imaging of SN 1987A

Using the Thermal Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8 m telescope, we have detected and resolved 10 μm emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. Hot spots similar to those found in the optical and near-IR are clearly present. The morphology of the 10 μm emission is globally similar to the morphology at other wavelengths from X-rays to radio. The observed mid-IR flux in the region of SN 1987A is probably dominated by emission from dust in the ER. We have also detected the ER at 20 μm at a 4 σ level. Assuming that thermal dust radiation is the origin of the mid-IR emission, we derive a dust temperature of 180 K and a dust mass of × 10-5 M☉ for the ER. Our observations also show a weak detection of the central ejecta at 10 μm. We show that previous bolometric flux estimates (through day 2100) were not significantly contaminated by this newly discovered emission from the ER. If we assume that the energy input comes from radioactive decays only, our measurements, together with the current theoretical models, set a temperature of 90 K ≤ T ≤ 100 K and a mass range of 10-4 to 2 × 10-3 M☉ for the dust in the ejecta. With such dust temperatures the estimated thermal emission is × 1035 ergs s-1 from the inner ring and × 1036 ergs s-1 from the ejecta. Finally, using SN 1987A as a template, we discuss the possible role of supernovae as major sources of dust in the universe.

A rotating collapsar and possible interpretation of the LSD neutrino signal from SN 1987A

We consider an improved rotational mechanism of the explosion of a collapsing supernova. We show that this mechanism leads to two-stage collapse with a phase difference of \sim 5 h. Based on this model, we attempt a new interpretation of the events in underground neutrino detectors on February 23, 1987, related to the supernova SN 1987A.

44Ti radioactivity in young supernova remnants: Cas A and SN 1987A

We investigate radioactivity from the decay sequence of 44Ti in young supernova remnants (SNRs), Cassiopeia A (Cas A) and SN 1987A. It is shown by a linear analysis that ionization of 44Ti, a pure electron capture decay isotope, affects the radioactivity contradistinctively in these two SNRs: Ionization of 44Ti to H-like and He-like states enhances its present radioactivity in Cas A, while such high-ionization decreases its radioactivity in SN 1987A. We briefly discuss the enhancement factor of the present radioactivity of Cas A considering microscopic (atomic/nuclear) physics combined with a hydrodynamical SNR evolution model. For SN 1987A, we have obtained the initial 44Ti mass of (0.82–2.3)×10 −4 M ⊙ from our Monte-Carlo simulations. The resulting fluxes of γ and hard X-rays emerged from the 44Ti decay are given for the current and future experiments.

Supernova neutrinos and the LSND evidence for neutrino oscillations

The observation of the $\bar{\nu}_e$ energy spectrum from a supernova burst can provide constraints on neutrino oscillations. We derive formulas for adiabatic oscillations of supernova antineutrinos for a variety of 3- and 4-neutrino mixing schemes and mass hierarchies which are consistent with the LSND evidence for $\bar{\nu}_{\mu}\to \bar{\nu}_e$ oscillations. Finally, we explore the constraints on these models and LSND given by the supernova SN1987A $\bar{\nu}_e$'s observed by the Kamiokande-2 and IMB-3 detectors.

Twenty years of Galactic observations in searching for bursts of collapse neutrinos with the Baksan underground scintillation telescope

The results of twenty-year-long Galactic observations in neutrino radiation are summarized. Except for the recording of a neutrino signal from the supernova SN 1987A, no Galactic bursts of collapse neutrinos have been detected. An upper bound on the mean frequency of gravitational collapses in our Galaxy was obtained, f collapse (at 90% confidence) <0.13 yr−1.

Another view of nucleosynthetic radioactivity

We discuss the prospects for direct measurements of nucleosynthesis yields of electron capture decay radioactive nuclei from supernovae, by detecting the characteristic K X-rays of the daughters. Several isotopes in galactic supernova remnants and SN 1987A appear to be detectable now or in the near future. Precise measurements of these nuclear yields, mostly achievable no other way, would greatly constrain nucleosynthesis theory.

Supernova 1987A bound on neutrino spectra forr-process nucleosynthesis

The neutrino driven wind during a core collapse supernova is an attractive site for r-process nucleosynthesis. The initial electron fraction ${Y}_{e}$ in the wind depends on observable neutrino energies and luminosities. The mean antineutrino energy is limited by supernova SN 1987A data while lepton number conservation constrains the ratio of antineutrino to neutrino luminosities. If ${Y}_{e},$ in the wind, is to be suitable for rapid neutron capture nucleosynthesis, then the mean electron neutrino energy could be significantly lower than that predicted in present supernova simulations. Alternatively, there could be a rapid increase of the mean antineutrino energy at late times. However, this is not seen in the SN 1987A data. Finally, there could be new neutrino physics such as oscillations to sterile neutrinos.