Supernova light curves pow ered by young m agnetars
01 Jan 2013-
TL;DR: In this article, the authors show that energy injected into an expanding supernova by a highly magnetic (B � 5 � 10 14 G)neutron starspinning at an initial period of Pi 2 20 m scan substantially brightens the lightcurve.
Abstract: W e show thatenergy deposited into an expanding supernova rem nantby a highly m agnetic (B � 5 � 10 14 G)neutron starspinning atan initialperiod of Pi � 2 20 m scan substantially brighten the lightcurve. Form agnetarswith param etersin thisrange,the rotationalenergy isreleased on a tim escaleofdaysto weeks,which iscom parableto theeectivediusion tim ethrough thesupernova rem nant.Thelatetim eenergyinjectioncanthenberadiatedwithoutsueringoverwhelm ingadiabatic expansion losses. The m agnetar input also produces a centralbubble which sweeps ejecta into an internaldense shell,resulting in a prolonged period ofnearly constantphotospheric velocity in the observed spectra.W ederiveanalyticexpressionsforthelightcurverisetim eand peak lum inosity as a function of B, Pi and the propertiesofthe supernova ejecta thatallow fordirectinferencesabout the underlying m agnetar in bright supernovae. W e perform num ericalradiation hydrodynam ical calculations ofa few specic instances and com pare the resulting light curves to observed events. M agnetaractivity is likely to im pact m ore than a few percentofallcore collapse supernovae,and m ay naturally explain som e ofthe brightest events ever seen (e.g.,SN 2005ap and SN 2008es) at L & 10 44 ergss 1 . Subjectheadings: radiativetransfer{ stars:neutron { supernovae:general{ supernovae:individual (SN 2005ap,SN 2008es,SN 2007bi)
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TL;DR: The neutrino-heating mechanism, aided by nonradial flows, drives explosions, albeit low-energy ones, of O-Ne-Mg-core and some Fe-core progenitors as mentioned in this paper.
Abstract: Supernova theory, numerical and analytic, has made remarkable progress in the past decade. This progress was made possible by more sophisticated simulation tools, especially for neutrino transport, improved microphysics, and deeper insights into the role of hydrodynamic instabilities. Violent, large-scale nonradial mass motions are generic in supernova cores. The neutrino-heating mechanism, aided by nonradial flows, drives explosions, albeit low-energy ones, of O-Ne-Mg-core and some Fe-core progenitors. The characteristics of the neutrino emission from newborn neutron stars were revised, new features of the gravitational-wave signals were discovered, our notion of supernova nucleosynthesis was shattered, and our understanding of pulsar kicks and explosion asymmetries was significantly improved. But simulations also suggest that neutrino-powered explosions might not explain the most energetic supernovae and hypernovae, which seem to demand magnetorotational driving. Now that modeling is being advanced from...
971 citations
TL;DR: In this paper, the authors presented the results of the Dark Energy Survey (DES) 2013, 2014, 2015, 2016, 2017, 2018, 2019 and 2019 at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign.
Abstract: US Department of Energy; US National Science Foundation; Ministry of Science and Education of Spain; Science and Technology Facilities Council of the United Kingdom; Higher Education Funding Council for England; National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign; Kavli Institute of Cosmological Physics at the University of Chicago; Center for Cosmology and Astro-Particle Physics at the Ohio State University; Mitchell Institute for Fundamental Physics and Astronomy at Texas AM University; Financiadora de Estudos e Projetos; Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico and the Ministerio da Ciencia; Tecnologia e Inovacao; Deutsche Forschungsgemeinschaft; Collaborating Institutions in the Dark Energy Survey; National Science Foundation [AST-1138766]; University of California at Santa Cruz; University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid; University of Chicago, University College London; DES-Brazil Consortium; University of Edinburgh; Eidgenossische Technische Hochschule (ETH) Zurich, Fermi National Accelerator Laboratory; University of Illinois at Urbana-Champaign; Institut de Ciencies de l'Espai (IEEC/CSIC); Institut de Fisica d'Altes Energies, Lawrence Berkeley National Laboratory; Ludwig-Maximilians Universitat Munchen; European Research Council [FP7/291329]; MINECO [AYA2012-39559, ESP2013-48274, FPA2013-47986]; Centro de Excelencia Severo Ochoa [SEV-2012-0234]; European Research Council under the European Union [240672, 291329, 306478]
789 citations
TL;DR: For example, the authors showed that mass loss rates for standard metallicity-dependent winds of hot stars are lower by a factor of 2-3 compared with rates adopted in modern stellar evolution codes, due to the influence of clumping on observed diagnostics.
Abstract: Our understanding of massive star evolution is in flux due to recent upheavals in our view of mass loss and observations of a high binary fraction among O-type stars. Mass-loss rates for standard metallicity-dependent winds of hot stars are lower by a factor of 2–3 compared with rates adopted in modern stellar evolution codes, due to the influence of clumping on observed diagnostics. Weaker hot star winds shift the burden of H-envelope removal to the winds, pulsations, and eruptions of evolved supergiants, as well as binary mass transfer. Studies of stripped-envelope supernovae, in particular, require binary mass transfer. Dramatic examples of eruptive mass loss are seen in Type IIn supernovae, which have massive shells ejected just a few years earlier. These eruptions are a prelude to core collapse, and may signify severe instabilities in the latest nuclear burning phases. We encounter the predicament that the most important modes of mass loss are also the most uncertain, undermining the predictive power...
755 citations
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TL;DR: High-resolution spectroscopy of the supernova PTF 11kx is reported, which was detected on 26 January 2011 by the Palomar Transient Factory survey, and the data suggest a red giant star companion whose material got transferred to the white dwarf.
Abstract: Supernovae (SNe), the luminous explosions of stars, were observed since antiquity, with typical peak luminosity not exceeding 12x10^{43} erg/s (absolute magnitude >-195 mag) It is only in the last dozen years that numerous examples of SNe that are substantially super-luminous (>7x10^{43} erg/s; <-21 mag absolute) were well-documented Reviewing the accumulated evidence, we define three broad classes of super-luminous SN events (SLSNe) Hydrogen-rich events (SLSN-II) radiate photons diffusing out from thick hydrogen layers where they have been deposited by strong shocks, and often show signs of interaction with circumstellar material SLSN-R, a rare class of hydrogen-poor events, are powered by very large amounts of radioactive 56Ni and arguably result from explosions of very massive stars due to the pair instability A third, distinct group of hydrogen-poor events emits photons from rapidly-expanding hydrogen-poor material distributed over large radii, and are not powered by radioactivity (SLSN-I) These may be the hydrogen-poor analogs of SLSN-II
664 citations
California Institute of Technology1, Weizmann Institute of Science2, University of Oxford3, Lawrence Berkeley National Laboratory4, University of California, Santa Barbara5, Las Cumbres Observatory Global Telescope Network6, Tel Aviv University7, Kavli Institute for Theoretical Physics8, University of California, San Diego9, University of Toronto10, University of California, Berkeley11
TL;DR: Observations of a class of luminous supernovae whose properties cannot be explained by any of the following processes: radioactive decay of freshly synthesized elements, explosion shock in the envelope of a supergiant star, and interaction between the debris and slowly moving, hydrogen-rich circumstellar material.
Abstract: Supernovae are stellar explosions driven by gravitational or thermonuclear energy that is observed as electromagnetic radiation emitted over weeks or more. In all known supernovae, this radiation comes from internal energy deposited in the outflowing ejecta by one or more of the following processes: radioactive decay of freshly synthesized elements (typically ^(56)Ni), the explosion shock in the envelope of a supergiant star, and interaction between the debris and slowly moving, hydrogen-rich circumstellar material. Here we report observations of a class of luminous supernovae whose properties cannot be explained by any of these processes. The class includes four new supernovae that we have discovered and two previously unexplained events, (SN 2005ap and SCP 06F6) that we can now identify as members of the same class. These supernovae are all about ten times brighter than most type Ia supernova, do not show any trace of hydrogen, emit significant ultraviolet flux for extended periods of time and have late-time decay rates that are inconsistent with radioactivity. Our data require that the observed radiation be emitted by hydrogen-free material distributed over a large radius (~10^(15) centimetres) and expanding at high speeds (>10^4 kilometres per second). These long-lived, ultraviolet-luminous events can be observed out to redshifts z > 4.
615 citations
Cites background from "Supernova light curves pow ered by ..."
...For example, a spinning-down nascent magnetar[19, 20] can account for the peak luminosities (> 10(44) erg s) and time to peak light (30-50 days) observed for these events, assuming a magnetic field B ≈ 1-3× 10(14)G and a natal spin of 1-3ms....
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References
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TL;DR: In this article, it is argued that a convective dynamo can also generate a very strong dipole field after the merger of a neutron star binary, but only if the merged star survives for as long as about 10-100 ms.
Abstract: It is proposed that the main observational signature of magnetars, high-field neutron stars, is gamma-ray bursts powered by their vast reservoirs of magnetic energy. If they acquire large recoils, most magnetars are unbound from the Galaxy or reside in an extended, weakly bound Galactic corona. There is evidence that the soft gamma repeaters are young magnetars. It is argued that a convective dynamo can also generate a very strong dipole field after the merger of a neutron star binary, but only if the merged star survives for as long as about 10-100 ms. Several mechanisms which could impart a large recoil to these stars at birth, sufficient to escape from the Galactic disk, are discussed.
2,482 citations
"Supernova light curves pow ered by ..." refers background in this paper
...Such highly magnetized neutron stars (NSs) were theoretically predicted (Duncan & Thompson 1992; Thompson & Duncan 1993), and most of their activity (both sporadic and persistent) must be powered by the decay of these large magnetic fields....
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California Institute of Technology1, Lawrence Berkeley National Laboratory2, University of California, Berkeley3, University of California, Santa Barbara4, Las Cumbres Observatory Global Telescope Network5, Weizmann Institute of Science6, Max Planck Society7, American Museum of Natural History8, University of Oxford9
TL;DR: The Palomar Transient Factory (PTF) as mentioned in this paper is a fully-automated, wide-field survey aimed at a systematic exploration of the optical transient sky.
Abstract: The Palomar Transient Factory (PTF) is a fully-automated, wide-field survey aimed at a systematic exploration of the optical transient sky. The transient survey is performed using a new 8.1 square degree camera installed on the 48 inch Samuel Oschin telescope at Palomar Observatory; colors and light curves for detected transients are obtained with the automated Palomar 60 inch telescope. PTF uses 80% of the 1.2 m and 50% of the 1.5 m telescope time. With an exposure of 60 s the survey reaches a depth of m_(g′) ≈ 21.3 and m_R ≈ 20.6 (5σ, median seeing). Four major experiments are planned for the five-year project: (1) a 5 day cadence supernova search; (2) a rapid transient search with cadences between 90 s and 1 day; (3) a search for eclipsing binaries and transiting planets in Orion; and (4) a 3π sr deep H-alpha survey. PTF provides automatic, real-time transient classification and follow-up, as well as a database including every source detected in each frame. This paper summarizes the PTF project, including several months of on-sky performance tests of the new survey camera, the observing plans, and the data reduction strategy. We conclude by detailing the first 51 PTF optical transient detections, found in commissioning data.
1,312 citations
"Supernova light curves pow ered by ..." refers background in this paper
...Our initial investigations have revealed that if an appreciable fraction of highly magnetic NSs are born rapidly rotating, then we should find evidence for them in the plethora of supernovae surveys, such as the Palomar Transient Factory (Law et al. 2009)....
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TL;DR: In this paper, the authors reported the discovery of pulsations in the persistent X-ray flux of SGR1806-20, with a period of 7.47 s and a spindown rate of 2.6 x 10(exp -3) s/yr.
Abstract: Soft gamma-ray repeaters (SGRs) emit multiple, brief (approximately O.1 s) intense outbursts of low-energy gamma-rays. They are extremely rare; three are known in our galaxy and one in the Large Magellanic Cloud. Two SGRs are associated with young supernova remnants (SNRs), and therefore most probably with neutron stars, but it remains a puzzle why SGRs are so different from 'normal' radio pulsars. Here we report the discovery of pulsations in the persistent X-ray flux of SGR1806-20, with a period of 7.47 s and a spindown rate of 2.6 x 10(exp -3) s/yr. We argue that the spindown is due to magnetic dipole emission and find that the pulsar age and (dipolar) magnetic field strength are approximately 1500 years and 8 x 10(exp 14) gauss, respectively. Our observations demonstrate the existence of 'magnetars', neutron stars with magnetic fields about 100 times stronger than those of radio pulsars, and support earlier suggestions that SGR bursts are caused by neutron-star 'crust-quakes' produced by magnetic stresses. The 'magnetar' birth rate is about one per millenium, a substantial fraction of that of radio pulsars. Thus our results may explain why some SNRs have no radio pulsars.
980 citations
"Supernova light curves pow ered by ..." refers background in this paper
...Studies of soft gamma-ray repeaters and anomalous X-ray pulsars reveal that ∼ 10% of newly born neutron stars (Kouveliotou et al. 1998) have dipole magnetic fields as high as B ∼ 1014 − 1015 G for more than 1000 years after their birth (see Woods & Thompson 2006)....
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TL;DR: In this article, it is argued that most of the magnetic energy becomes concentrated in thin flux ropes when the field pressure exceeds the turbulent pressure at the smallest scale of turbulence, and the possibilities for dynamo action during the various (precollapse) stages of convective motion that occur in the evolution of a massive star are examined.
Abstract: Neutron star convection is a transient phenomenon and has an extremely high magnetic Reynolds number In this sense, a neutron star dynamo is the quintessential fast dynamo The convective motions are only mildly turbulent on scales larger than the approximately 100 cm neutrino mean free path, but the turbulence is well developed on smaller scales Several fundamental issues in the theory of fast dynamos are raised in the study of a neutron star dynamo, in particular the possibility of dynamo action in mirror-symmetric turbulence It is argued that in any high magnetic Reynolds number dynamo, most of the magnetic energy becomes concentrated in thin flux ropes when the field pressure exceeds the turbulent pressure at the smallest scale of turbulence In addition, the possibilities for dynamo action during the various (pre-collapse) stages of convective motion that occur in the evolution of a massive star are examined, and the properties of white dwarf and neutron star progenitors are contrasted
917 citations
"Supernova light curves pow ered by ..." refers background in this paper
...Such highly magnetized neutron stars (NSs) were theoretically predicted (Duncan & Thompson 1992; Thompson & Duncan 1993), and most of their activity (both sporadic and persistent) must be powered by the decay of these large magnetic fields....
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TL;DR: Differential photometry offers the most precise method for measuring the brightness of astronomical objects as mentioned in this paper, and it has been used extensively in the application of differential techniques from the earliest visual methods to photoelectric and CCD photometry.
Abstract: Differential photometry offers the most precise method for measuring the brightness of astronomical objects. We attempt to demonstrate why this should be the case, and then describe how well it has been done through a review of the application of differential techniques from the earliest visual methods to photoelectric and CCD photometry. We pay special attention to the work of Theodore Walraven and his legacy.
535 citations