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1

Rotating Neutron Stars, Pulsars and Supernova Remnants  

Microsoft Academic Search

I SHALL discuss here some problems connected with theories linking the pulsars to the rotation of neutron stars (ref. 1 and a preprint by L. Woltjer). Because neutron stars can be formed during a supernova explosion, their rotation could be coupled with the surrounding gaseous remnant2,3: the following considerations will therefore also refer to the problem of the activity observed

F. Pacini

1968-01-01

2

Confinement of the Crab pulsar's wind by its supernova remnant  

Microsoft Academic Search

A steady state, spherically symmetric, magnetohydrodynamic model of the Crab nebula is constructed. A highly relativistic positronic pulsar wind is terminated by a strong MHD shock that decelerates the flow and increases its pressure to match boundary conditions imposed by the recently discovered supernova remnant that surrounds the nebula. If the magnetic luminosity of the pulsar wind upstream of the

C. F. Kennel; F. V. Coroniti

1984-01-01

3

TeV gamma-rays from Galactic objects: pulsars, pulsar nebulae and supernova remnants  

E-print Network

to the success of ground-based tech- nique for TeV gamma rays. The current status of gamma ray astronomy can and a supernova remnant. The VHE gamma ray astronomy in `the CGRO Era' is summarized and discussed for exam- TableTeV gamma-rays from Galactic objects: pulsars, pulsar nebulae and supernova remnants T. Kifune

Enomoto, Ryoji

4

Pulsar Wind Nebulae in Evolved Supernova Remnants  

Microsoft Academic Search

For pulsars similar to the one in the Crab Nebula, most of the energy input\\u000ato the surrounding wind nebula occurs on a timescale of less than 1000 years;\\u000aduring this time, the nebula expands into freely expanding supernova ejecta. On\\u000aa timescale 10,000 years, the interaction of the supernova with the surrounding\\u000amedium drives a reverse shock front toward

John M. Blondin; Roger A. Chevalier; Dargan M. Frierson

2001-01-01

5

TeV gammarays from Galactic objects: pulsars, pulsar nebulae and supernova remnants  

E-print Network

to the success of ground­based tech­ nique for TeV gamma rays. The current status of gamma ray astronomy can and a supernova remnant. The VHE gamma ray astronomy in `the CGRO Era' is summarized and discussed for exam­ TableTeV gamma­rays from Galactic objects: pulsars, pulsar nebulae and supernova remnants T. Kifune

Enomoto, Ryoji

6

Pulsar Wind Nebulae, Space Velocities and Supernova Remnant  

NASA Technical Reports Server (NTRS)

The original proposal for this LTSA grant was for X-ray studies of pulsars, and especially pulsar wind nebulae and what they could tell us about pulsar properties, especially their space velocities. By any metric, this program has been very successful. No fewer than 14 papers on directly related topics (and several dozen more on related topics) have been published in refereed journals with the PI as lead or co-author, all observational results that have had significant impact on the field. These include the first X-ray detection of the "Duck" pulsar, a clear demonstration that estimated pulsar ages can be off by over an order of magnitude (via observations of the young supernova remnant G11.2-0.3) and the detection of the first pulsar wind nebula around a millisecond pulsar. These publications have also resulted in 4 press releases. Moreover, they also represent the thesis work of two PhD students at MIT (Froney Crawford and Mike Pivovaroff) and one postdoctoral fellow, Bryan Gaensler, now Assistant Professor at Harvard.

2005-01-01

7

Rejuvenating the shells of supernova remnants by pulsar winds  

E-print Network

We reconsider the rejuvenation mechanism as proposed by Shull, Fesen, & Saken (1989). These authors suggest that an active pulsar can catch up with, and rejuvenate the shell of the associated supernova remnant. The morphology of the SNRs G5.4-1.2 and CTB80 seem to confirm this rejuvenation mechanism. The spindown energy is deposited by the pulsar as a relativistic pulsar wind, and has a sufficient power to explain the observed radio emission observed in these remnants. Shull et al. (1989) did {\\it not} explain the observed lengthscales of the rejuvenated parts of the SNR shell. therefore one needs to consider the diffusive transport of the injected electrons by the pulsar wind. We propose to apply a diffusion mechanism as introduced by Jokipii (1987), which makes a distinction between diffusion along the magnetic field lines and perpendicular to the magnetic field lines, parameterised by the gyro factor $\\eta$. We show that one has to assume a high value for the gyro factor, $\\eta\\simeq 10^3-10^4$, i.e. diffusion of the electrons along the magnetic field line is much faster then perpendicular to the magnetic field line, in order for the rejuvenation mechanism to work on the observed lengthscales.

Eric van der Swaluw; Abraham Achterberg; Yves A. Gallant

2001-12-17

8

Future GLAST observations of Supernova remnants and Pulsar Wind Nebulae  

NASA Astrophysics Data System (ADS)

Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of Diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of ~100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young SNR SN1006. Furthermore using theoretical arguments shell-type Supernova remnants have long been considered as the main accelerator of protons - Cosmic rays - in the Galaxy; definite proof of this process is however still missing. Pulsar Wind Nebulae (PWN) - diffuse structures surrounding young pulsars - are another class of objects known to be a site of particle acceleration in the Galaxy, again through the detection of hard synchrotron X-rays such as in the Crab Nebula. Gamma-rays above 100 MeV provide a direct access to acceleration processes. Ultra-relativistic electrons emit gamma-radiation through Inverse Compton scattering in ubiquitous photon fields (such as CMBR, star light and dust emission or local synchrotron radiation), protons emit gamma-radiation through the decay of pi0s, generated in proton-proton interactions with Interstellar material such as gas clouds. Recent advances in ground-based gamma-ray astronomy e.g. made by Cherenkov Telescopes above an energy threshold of 100 GeV have shown, that both shell-type SNRs and PWN are classes of gamma-ray emitting objects in the Galaxy. The upcoming GLAST Large Area Telescope (LAT) will be operating in the energy range between 30 MeV and 300 GeV and will provide excellent sensitivity, angular and energy resolution in a poorly investigated energy band. Shell-type SNRs as well as PWN provide natural targets for GLAST observations and detections. We will describe prospects for the investigation of these Galactic particle accelerators with GLAST.

Funk, S.

9

Particle Acceleration in Supernova Remnants and Pulsar Wind Nebulae  

E-print Network

While supernova remnants (SNRs) have long been considered prime candidates for the source of cosmic rays, at least to energies up to ~10^14 eV, it is only over the past several years that direct evidence of such energetic particles in SNRs has been uncovered. X-ray observations of several shell-type SNRs have now revealed sites dominated by nonthermal emission, indicating an electron population whose energy extends far beyond the thermal distribution typical of such SNRs. In other remnants, discrepancies between the shock velocity and the electron temperature points to a strong cosmic ray component that has essentially thrived at the expense of the thermal component of the gas. Modeling of the radio, X-ray, and gamma-ray emission provides strong constraints on the acceleration mechanism as well as the properties of the ambient medium in which the mechanism prospers. In the innermost regions of some SNRs, particle acceleration is taking place over much different scales. The formation of Crab-like pulsar wind nebulae (PWNe) is understood to require the presence of a termination shock at which the relativistic pulsar wind is forced to join the slow expansion of the outer nebula. While the acceleration mechanism is necessarily different, these shocks also act as sites in which particles are boosted to high energies. In the Crab Nebula, optical wisps mark the location of this termination shock. Recent X-ray observations have begun to reveal the termination shock zones in other PWNe, and are now allowing us to constrain the nature of the pulsar wind as well as the flow conditions in the outer nebula. Here I present a summary of the properties of shock acceleration in these two distinct regions of SNRs, and review recent observational results in which the properties of the shocks are finally being revealed.

Patrick Slane

2002-05-28

10

Comparing supernova remnants around strongly magnetized and canonical pulsars  

NASA Astrophysics Data System (ADS)

The origin of the strong magnetic fields measured in magnetars is one of the main uncertainties in the neutron star field. On the other hand, the recent discovery of a large number of such strongly magnetized neutron stars is calling for more investigation on their formation. The first proposed model for the formation of such strong magnetic fields in magnetars was through alpha-dynamo effects on the rapidly rotating core of a massive star. Other scenarios involve highly magnetic massive progenitors that conserve their strong magnetic moment into the core after the explosion, or a common envelope phase of a massive binary system. In this work, we do a complete re-analysis of the archival X-ray emission of the supernova remnants (SNRs) surrounding magnetars, and compare our results with all other bright X-ray emitting SNRs, which are associated with compact central objects (which are proposed to have magnetar-like B-fields buried in the crust by strong accretion soon after their formation), high-B pulsars and normal pulsars. We find that emission lines in SNRs hosting highly magnetic neutron stars do not differ significantly in elements or ionization state from those observed in other SNRs, neither averaging on the whole remnants, nor studying different parts of their total spatial extent. Furthermore, we find no significant evidence that the total X-ray luminosities of SNRs hosting magnetars, are on average larger than that of typical young X-ray SNRs. Although biased by a small number of objects, we found that for a similar age, there is the same percentage of magnetars showing a detectable SNR than for the normal pulsar population.

Martin, J.; Rea, N.; Torres, D. F.; Papitto, A.

2014-11-01

11

Future GLAST Observations of Supernova Remnants and Pulsar Wind Nebulae  

NASA Astrophysics Data System (ADS)

Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of Diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of 100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young SNR SN1006. Furthermore using theoretical arguments shell-type Supernova remnants have long been considered as the main accelerator of protons Cosmic rays in the Galaxy; definite proof of this process is however still missing. Pulsar Wind Nebulae (PWN) diffuse structures surrounding young pulsars are another class of objects known to be a site of particle acceleration in the Galaxy, again through the detection of hard synchrotron X-rays such as in the Crab Nebula. Gamma-rays above 100 MeV provide a direct access to acceleration processes. Ultra-relativistic electrons emit gamma-radiation through Inverse Compton scattering in ubiquitous photon fields (such as CMBR, star light and dust emission or local synchrotron radiation), protons emit gamma-radiation through the decay of pi0s, generated in proton-proton interactions with Interstellar material such as gas clouds. Recent advances in ground-based gamma-ray astronomy e.g. made by Cherenkov Telescopes above an energy threshold of 100 GeV have shown, that both shell-type SNRs and PWN are classes of gamma-ray emitting objects in the Galaxy. The upcoming GLAST Large Area Telescope (LAT) will be operating in the energy range between 30 MeV and 300 GeV and will provide excellent sensitivity, angular and energy resolution in a poorly investigated energy band. Shell-type SNRs as well as PWN provide natural targets for GLAST observations and detections and in this poster we will describe prospects for the investigation of these Galactic particle accelerators with GLAST.

Funk, Stefan; LAT Collab. Pulsars, GLAST; SNR; Plerions Group

2006-12-01

12

The Fermi Gamma-Ray Space Telescope Discovers the Pulsar in the Young Galactic Supernova Remnant CTA 1  

Microsoft Academic Search

Energetic young pulsars and expanding blast waves [supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a

A. A. Abdo; M. Ackermann; W. B. Atwood; L. Baldini; J. Ballet; G. Barbiellini; M. G. Baring; D. Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; B. Berenji; R. D. Blandford; E. D. Bloom; G. Bogaert; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; P. Carlson; J. M. Casandjian; C. Cecchi; E. Charles; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; S. Cutini; D. S. Davis; C. D. Dermer; A. de Angelis; F. de Palma; S. W. Digel; M. Dormody; E. do Couto e Silva; P. S. Drell; R. Dubois; D. Dumora; Y. Edmonds; C. Farnier; W. B. Focke; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; A. K. Harding; R. C. Hartman; E. Hays; R. E. Hughes; G. Jhannesson; A. S. Johnson; R. P. Johnson; T. J. Johnson; W. N. Johnson; T. Kamae; Y. Kanai; G. Kanbach; H. Katagiri; N. Kawai; M. Kerr; T. Kishishita; B. Kiziltan; J. Kndlseder; M. L. Kocian; N. Komin; F. Kuehn; M. Kuss; L. Latronico; M. Lemoine-Goumard; F. Longo; V. Lonjou; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; J. E. McEnery; S. McGlynn; C. Meurer; P. F. Michelson; T. Mineo; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; T. Nakamori; P. L. Nolan; E. Nuss; M. Ohno; T. Ohsugi; A. Okumura; N. Omodei; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pesce-Rollins; G. Piano; L. Pieri; F. Piron; T. A. Porter; S. Rain; R. Rando; P. S. Ray; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; S. Ritz; L. S. Rochester; A. Y. Rodriguez; R. W. Romani; M. Roth; F. Ryde; H. F.-W. Sadrozinski; D. Sanchez; A. Sander; P. M. Saz Parkinson; T. L. Schalk; A. Sellerholm; C. Sgr; E. J. Siskind; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; J.-L. Starck; M. S. Strickman; D. J. Suson; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; S. E. Thorsett; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; T. L. Usher; A. Van Etten; N. Vilchez; V. Vitale; P. Wang; K. Watters; B. L. Winer; K. S. Wood; H. Yasuda; T. Ylinen; M. Ziegler

2008-01-01

13

Future GLAST observations of Supernova remnants and Pulsar Wind Nebulae  

Microsoft Academic Search

Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of Diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of ~100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young

S. Funk

2008-01-01

14

Future GLAST Observations of Supernova Remnants and Pulsar Wind Nebulae  

Microsoft Academic Search

Shell-type Supernova remnants (SNRs) have long been known to harbour a population of ultra-relativistic particles, accelerated in the Supernova shock wave by the mechanism of Diffusive shock acceleration. Experimental evidence for the existence of electrons up to energies of 100 TeV was first provided by the detection of hard X-ray synchrotron emission as e.g. in the shell of the young

Stefan Funk; GLAST LAT Collab. Pulsars

2006-01-01

15

The Gamma-ray Pulsar in the CTA1 Supernova Remnant  

NASA Astrophysics Data System (ADS)

The gamma-ray pulsar in the CTA1 supernova remnant was the first to be discovered in a blind search with the Fermi LAT. With a surface magnetic field strength of 1.1x1013 Gauss, this pulsar has the highest surface magnetic field strength among the 46 gamma-ray pulsars detected by Fermi in the first six months of the mission (Abdo et al. 2009). In May 2009 this pulsar had a glitch, Df/f=5x10-7. This is one of a few glitches detected to date in Fermi gamma-ray pulsars. We will present results from the first 15 months of the Fermi mission. Detailed studies of the energetics and variability studies of this source, especially around the time of the glitch, will be presented. The surrounding region contains both a PWN and SNR, which provide constraints on the age and energetic budget complementary to those obtained from period derivatives.

Abdo, Aous; Fermi LAT Collaboration

2010-02-01

16

BeppoSAX Observations of the Young Pulsar in the Kes 75 Supernova Remnant  

Microsoft Academic Search

We present the results of BeppoSAX observations of the young X-ray pulsar PSR J1846-0258, recently discovered at the center of the composite supernova remnant Kes 75. The pulsar (plus nebula) spectrum can be fitted by an absorbed power law with photon index alphaph=2.16+\\/-0.15, NH=(4.7+\\/-0.8)1022 cm-2, and unabsorbed flux ~3.910-11 ergs cm-2 s-1 (2-10 keV). By joining two observations taken at

S. Mereghetti; R. Bandiera; F. Bocchino; G. L. Israel

2002-01-01

17

The Fermi Gamma Ray Space Telescope discovers the Pulsar in the Young Galactic Supernova-Remnant CTA 1  

SciTech Connect

Energetic young pulsars and expanding blast waves (supernova remnants, SNRs) are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 ms, a period derivative of 3.614 x 10{sup -13} s s{sup -1}. Its characteristic age of 10{sup 4} years is comparable to that estimated for the SNR. It is conjectured that most unidentified Galactic gamma ray sources associated with star-forming regions and SNRs are such young pulsars.

Abdo, Aous A.; Ackermann, M.; Atwood, W.B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M.G.; Bastieri, Denis; Baughman, B.M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.D.; Bloom, Elliott D.; Bogaert, G.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.

2009-05-15

18

The Fermi Gamma-Ray Space Telescope discovers the pulsar in the young galactic supernova remnant CTA 1.  

PubMed

Energetic young pulsars and expanding blast waves [supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 milliseconds and a period derivative of 3.614 x 10(-13) seconds per second. Its characteristic age of 10(4) years is comparable to that estimated for the SNR. We speculate that most unidentified Galactic gamma-ray sources associated with star-forming regions and SNRs are such young pulsars. PMID:18927355

Abdo, A A; Ackermann, M; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bogaert, G; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Carlson, P; Casandjian, J M; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Cutini, S; Davis, D S; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Dormody, M; do Couto E Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Focke, W B; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Harding, A K; Hartman, R C; Hays, E; Hughes, R E; Jhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Kanai, Y; Kanbach, G; Katagiri, H; Kawai, N; Kerr, M; Kishishita, T; Kiziltan, B; Kndlseder, J; Kocian, M L; Komin, N; Kuehn, F; Kuss, M; Latronico, L; Lemoine-Goumard, M; Longo, F; Lonjou, V; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Makeev, A; Marelli, M; Mazziotta, M N; McEnery, J E; McGlynn, S; Meurer, C; Michelson, P F; Mineo, T; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nolan, P L; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piano, G; Pieri, L; Piron, F; Porter, T A; Rain, S; Rando, R; Ray, P S; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Parkinson, P M Saz; Schalk, T L; Sellerholm, A; Sgr, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Starck, J-L; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Thorsett, S E; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Usher, T L; Van Etten, A; Vilchez, N; Vitale, V; Wang, P; Watters, K; Winer, B L; Wood, K S; Yasuda, H; Ylinen, T; Ziegler, M

2008-11-21

19

AN EXTREME PULSAR TAIL PROTRUDING FROM THE FRYING PAN SUPERNOVA REMNANT  

SciTech Connect

The Frying Pan (G315.9-0.0) is a radio supernova remnant with a peculiar linear feature (G315.78-0.23) extending 10' radially outward from the rim of the shell. We present radio imaging and polarization observations obtained from the Molonglo Observatory Synthesis Telescope and the Australia Telescope Compact Array, confirming G315.78-0.23 as a bow-shock pulsar wind nebula (PWN) powered by the young pulsar J1437-5959. This is one of the longest pulsar tails observed in radio and it has a physical extent over 20 pc. We found a bow-shock standoff distance of 0.002 pc, smallest among similar systems, suggesting a large pulsar velocity over 1000 km s{sup -1} and a high Mach number {approx}200. The magnetic field geometry inferred from radio polarimetry shows a good alignment with the tail orientation, which could be a result of high flow speed. There are also hints that the postshock wind has a low magnetization and is dominated by electrons and positrons in energy. This study shows that PWNe can offer a powerful probe of their local environment, particularly for the case of a bow shock where the parent supernova shell is also detected.

Ng, C.-Y.; Bouchard, A. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Bucciantini, N. [NORDITA, Albanova Research Center, 106 91 Stockholm (Sweden); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Chatterjee, S., E-mail: ncy@physics.mcgill.ca [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States)

2012-02-10

20

Chandra View of DA 530: A Sub-Energetic Supernova Remnant with a Pulsar Wind Nebula?  

E-print Network

Based on a Chandra ACIS observation, we report the detection of an extended X-ray feature close to the center of the remnant DA 530 with 5.3 sigma above the background within a circle of 20'' radius. This feature, characterized by a power-law with the photon index gamma=1.6+-0.8 and spatially coinciding with a nonthermal radiosource, most likely represents a pulsar wind nebula. We have further examined the spectrum of the diffuse X-ray emission from the remnant interior with a background-subtracted count rate of ~0.06 counts s^-1 in 0.3-3.5 keV. The spectrum of the emission can be described by a thermal plasma with a temperature of ~0.3-0.6 keV and a Si over-abundance of >~7 solar. These spectral characteristics, together with the extremely low X-ray luminosity, suggest that the remnant arises from a supernova with an anomalously low mechanical energy (<10^50 ergs). The centrally-filled thermal X-ray emission of the remnant may indicate an early thermalization of the SN ejecta by the circum-stellar medium. Our results suggest that the remnant is likely the product of a core-collapsed SN with a progenitor mass of 8-12 Msun. Similar remnants are probably common in the Galaxy, but have rarely been studied.

Bing Jiang; Yang Chen; Q. Daniel Wang

2007-08-08

21

Supernova remnants containing neutron stars  

NASA Technical Reports Server (NTRS)

X-ray observations of Crab Nebula-like supernova remnants are summarized. Five remnants are found to contain internal neutron stars - four isolated and one in a binary system. Another five remnants have central unresolved X-ray sources which are probably neutron stars. Thus approximately 10 remnants are now known to have their origin in gravitational collapse. Another 22 remnants show some Crab-like properties, but the existence of a central compact object or pulsar is doubtful or unconfirmed. The four fast isolated pulsars in SNR are also compared with five X-ray detected radio pulsars.

Seward, F. D.

1985-01-01

22

Progress on multi-waveband observations of supernova remnants  

Microsoft Academic Search

A number of observational advances have increased our knowledge about supernova remnants. In this paper we review the main progresses made in the last decade, including new discoveries of supernova remnants and the associated pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics and cosmic ray accelerations. keywords: Supernova remnant, observations Massive

Yang Xuejuan; Lu Fangjun; Tian Wenwu

23

ASTRO-H White Paper - Older Supernova Remnants and Pulsar Wind Nebulae  

E-print Network

Most supernova remnants (SNRs) are old, in the sense that their structure has been profoundly modified by their interaction with the surrounding interstellar medium (ISM). Old SNRs are very heterogenous in terms of their appearance, reflecting differences in their evolutionary state, the environments in which SNe explode and in the explosion products. Some old SNRs are seen primarily as a result of a strong shock wave interacting with the ISM. Others, the so-called mixed-morphology SNRs, show central concentrations of emission, which may still show evidence of emission from the ejecta. Yet others, the pulsar wind nebulae (PWNe), are seen primarily as a result of emission powered by a pulsar; these SNRs often lack the detectable thermal emission from the primary shock. The underlying goal in all studies of old SNRs is to understand these differences, in terms of the SNe that created them, the nature of the ISM into which they are expanding, and the fundamental physical processes that govern their evolution. He...

Long, K S; Aharonian, F; Foster, A; Funk, S; Hiraga, J; Hughes, J; Ishida, M; Katsuda, S; Matsumoto, H; Mori, K; Nakajima, H; Nakamori, T; Ozaki, M; Safi-Harb, S; Sawada, M; Tamagawa, T; Tamura, K; Tanaka, T; Tsunemi, H; Uchida, H; Uchiyama, Y; Yamauchi, S

2014-01-01

24

Chandra Studies of Nonthermal Emission from Supernova Remnants and Pulsar Wind Nebulae  

E-print Network

While supernova remnants (SNRs) have long been considered prime candidates as sources of cosmic rays, it is only recently that X-ray observations have identified several shell-type SNRs dominated by nonthermal emission, thus revealing shock-accelerated electrons with energies extending far beyond the typical thermal spectrum. Two of these SNRs have been detected as sources of VHE gamma-rays.In other remnants, discrepancies between the shock velocity and the electron temperature point to a strong cosmic ray component that has thrived at the expense of the thermal gas. Modeling of the radio, X-ray, and gamma-ray emission provides constraints on particle acceleration as well as the properties of the medium in which the mechanism prospers. Crab-like pulsar wind nebulae (PWNe) are characterized by a termination shock at which the wind is forced to join the slow expansion of the outer nebula. These shocks also act as sites in which particles are boosted to high energies; the X-ray emission from the Crab Nebula, as well as the inverse Compton radiation observed as VHE gamma-rays, imply electrons with energies in excess of ~100 TeV. Recent X-ray observations have begun to reveal these shock zones in the Crab and other PWNe, and are now allowing us to constrain the nature of pulsar winds as well as the flow conditions in the outer nebulae. Here I present a brief overview of recent studies with the Chandra X-ray Observatory in which the properties of these shock acceleration regions are finally being revealed.

Patrick Slane

2002-12-16

25

Progress on multi-waveband observations of supernova remnants  

E-print Network

The development of observational techniques has inriched our knowledge of supernova remnants. In this paper, we review the main progresses in the last decade, including new discoveries of supernova remnants and the associated (rare type of) pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics, and cosmic ray accelerations.

Xuejuan Yang; Fangjun Lu; Wenwu Tian

2008-10-23

26

Chandra View of DA 530: A Sub-Energetic Supernova Remnant with a Pulsar Wind Nebula?  

E-print Network

DA 530 (G93.3+6.9) is a high Galactic latitude supernova remnant with a well-defined shell-like radio morphology and an exceptionally low X-ray to radio luminosity ratio. Based on a Chandra ACIS observation, we report the detection of an extended X-ray feature close to the center of the remnant with 5.3 sigma above the background within a circle of 20''

Jiang, Bing; Wang, Q Daniel

2007-01-01

27

The Chandra View of DA 530: A Subenergetic Supernova Remnant with a Pulsar Wind Nebula?  

Microsoft Academic Search

DA 530 (G93.3+6.9) is a high Galactic latitude supernova (SN) remnant with a well-defined shell-like radio morphology and an exceptionally low X-ray-to-radio luminosity ratio. Based on a Chandra ACIS observation, we report the detection of an extended X-ray feature close to the center of the remnant at 5.3 sigma above the background within a circle of 20\\

Bing Jiang; Yang Chen; Q. Daniel Wang

2007-01-01

28

Deep optical observations of the gamma-ray pulsar PSR J0007+7303 in the CTA 1 supernova remnant  

E-print Network

The Fermi Large Area Telescope (LAT) discovered the time signature of a radio-silent pulsar coincident with RX J0007.0+7302, a plerion-like X-ray source at the centre of the CTA 1 supernova remnant. The inferred timing parameters of the gamma-ray pulsar PSR J0007+7303 (P=315.8 ms; dot{P}\\sim3.6 10^{-13} s s^{-1}) point to a Vela-like neutron star, with an age comparable to that of CTA 1. The PSR J0007+7303 low distance (\\sim 1.4 kpc), interstellar absorption (A_V\\sim 1.6), and relatively high energy loss rate (dot{E} \\sim4.5 10^{35} erg s^{-1}), make it a suitable candidate for an optical follow-up. Here, we present deep optical observations of PSR J0007+7303. The pulsar is not detected in the Gran Telescopio Canarias (GTC) images down to a limit of r'\\sim 27.6 (3 sigma), the deepest ever obtained for this pulsar, while William Herschel Telescope (WHT) images yield a limit of V \\sim 26.9. Our r'-band limit corresponds to an optical emission efficiency \\eta_{opt}= L_{opt}/dot{E} < 9.4 10^{-8}. This limit is...

Mignani, R P; Rea, N; Shearer, A; Collins, S; Torres, D F; Hadasch, D; Caliandro, A

2013-01-01

29

Neutron Stars in Supernova Remnants  

NASA Technical Reports Server (NTRS)

The grant provided funds for a conference entitled 'Neutron Stars in Supernova Remnants' held in Boston on 14-17 August 2001, in part to support invited speakers and students attending the meeting. The conference was completed on the specified dates and was a considerable success, attracting over 100 scientists from around the world. The conference included talks and papers on the most recent work in this field, including results from the Chandra X-ray Observatory, XMM-Newton, the Parkes Multibeam Pulsar Survey, the Very Large Array, and many other facilities. Theoretical work based on the latest results was also highlighted. The Proceedings of the conference have now been published as 'Neutron Stars in Supernova Remnants'. In addition, a large fraction of the papers from the conference have been submitted to astro-ph, and the volume in indexed through the Astronomical Data System.

Slane, Patrick; Kaluzienski, Lou (Technical Monitor)

2002-01-01

30

Timing Behavior of the Magnetically Active Rotation-Powered Pulsar in the Supernova Remnant Kesteven 75  

NASA Technical Reports Server (NTRS)

We report a large spin-up glitch in PSR J1846-0258 which coincided with the onset of magnetar-like behavior on 2006 May 31. We show that the pulsar experienced an unusually large glitch recovery, with a recovery fraction of Q = 5.9+/-0.3, resulting in a net decrease of the pulse frequency. Such a glitch recovery has never before been observed in a rotation-powered pulsar, however, similar but smaller glitch over-recovery has been recently reported in the magnetar AXP 4U 0142+61 and may have occurred in the SGR 1900+14. We discuss the implications of the unusual timing behavior in PSR J1846-0258 on its status as the first identified magnetically active rotation-powered pulsar.

Livingstone, Margaret A.; Gavriil, Fotis P.; Kaspi, Victoria M.

2009-01-01

31

Discovery of Radio Pulsations from the X-ray Pulsar JO205+6449 in Supernova Remnant 3C58 with the Green Bank Telescope  

NASA Technical Reports Server (NTRS)

We report the discovery with the 100m Green Bank Telescope of 65 ms radio pulsations from the X-ray pulsar J0205+6449 at the center of supernova remnant 3C58, making this possibly the youngest radio pulsar known. From our observations at frequencies of 820 and 1375 MHz, the free electron column density to USSR J0205+6449 is found to be 140.7 +/- 0.3/cc pc. The barycentric pulsar period P and P(dot) determined from a phase-coherent timing solution are consistent with the values previously measured from X-ray observations. The averaged radio profile of USSR J0205+6449 consists of one sharp pulse of width = 3 ms = 0.05 P. The pulsar is an exceedingly weak radio source, with pulse-averaged flux density in the 1400 MHz band of approximately 45 micro-Jy and a spectral index of approximately -2.1. Its radio luminosity of approximately 0.5 may kpc(exp 2) at 1400 MHz is lower than that of approximately 99% of known pulsar and is the lowest among known young pulsars.

Camilo, F.; Stairs, I. H.; Lorimer, D. R.; Backer, D. C.; Ransom, S. M.; Klein, B.; Wielebinski, R.; Kramer, M.; McLaughlin, M. A.; Arzoumanian, Z.; White, Nicholas E. (Technical Monitor)

2002-01-01

32

The Honeycomb supernova remnant  

NASA Technical Reports Server (NTRS)

At 2.5 min southeast of SN 1987A, the Honeycomb Nebula Supernova remnant (SNR) is named after its interesting morphology, which consists of over ten loops with sizes of 2-3 pc. High-dispersion spectra of these loops show hemispheres expanding toward the observer at 100-300 km/s. Using archival data X-ray data and a combination of new and archival radio data, we find bright X-ray and nonthermal radio emisssion associated with the Honeycomb Nebula. New CCD images further show enhanced (S II) H-alpha ratios. These results confirm a model in which the Honeycomb Nebula is due to a supernova shock front, traveling toward the observer, encountering an intervening sheet of dense, but porous, interstellar gas. The bulk of the supernova remnant resides in a low-density cavity, and is not otherwise visible. The situation is similar to the hidden supernova remnants postulated for the X-ray bright superbubbles. The Honeycomb Nebula has an unusually steep radio spectral index (S(sub nu) is proportional to nu(exp -1.2)), normally associated with young SNRs.

Chu, You-Hua; Dickel, John R.; Staveley-Smith, Lister; Osterberg, Juergen; Smith, R. Chris

1995-01-01

33

PROGENITORS OF RECOMBINING SUPERNOVA REMNANTS  

SciTech Connect

Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with ionization temperature higher than the electron temperature, has been recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the supernova explosion. If the circumstellar medium is dense enough, collisional ionization equilibrium can be established in the early stage of the evolution of the supernova remnant and subsequent adiabatic cooling, which occurs after the shock wave gets out of the dense circumstellar medium, makes the electron temperature lower than the ionization temperature. We study the circumstellar medium around several supernova progenitors and show which supernova progenitors can have a circumstellar medium dense enough to establish collisional ionization equilibrium soon after the explosion. We find that the circumstellar medium around red supergiants (especially massive ones) and the circumstellar medium dense enough to make Type IIn supernovae can establish collisional ionization equilibrium soon after the explosion and can evolve to become recombining supernova remnants. Wolf-Rayet stars and white dwarfs have the possibility to be recombining supernova remnants but the fraction is expected to be very small. As the occurrence rate of the explosions of red supergiants is much higher than that of Type IIn supernovae, the major progenitors of recombining supernova remnants are likely to be red supergiants.

Moriya, Takashi J., E-mail: takashi.moriya@ipmu.jp [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8583 (Japan)

2012-05-01

34

What Shapes Supernova Remnants?  

NASA Astrophysics Data System (ADS)

Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can have substantial deviations from spherical symmetry; one such piece of evidence is the complex morphologies of supernova remnants (SNRs). However, the relative role of the explosion geometry and the environment in shaping SNRs remains an outstanding question. Recently, we have developed techniques to quantify the morphologies of SNRs, and we have applied these methods to the extensive X-ray and infrared archival images available of Milky Way and Magellanic Cloud SNRs. In this proceeding, we highlight some results from these studies, with particular emphasis on SNR asymmetries and whether they arise from ``nature'' or ``nurture''.

Lopez, Laura A.

2014-01-01

35

DEEP X-RAY OBSERVATIONS OF THE YOUNG HIGH-MAGNETIC-FIELD RADIO PULSAR J1119-6127 AND SUPERNOVA REMNANT G292.2-0.5  

SciTech Connect

High-magnetic-field radio pulsars are important transition objects for understanding the connection between magnetars and conventional radio pulsars. We present a detailed study of the young radio pulsar J1119-6127, which has a characteristic age of 1900 yr and a spin-down-inferred magnetic field of 4.1 Multiplication-Sign 10{sup 13} G, and its associated supernova remnant G292.2-0.5, using deep XMM-Newton and Chandra X-ray Observatory exposures of over 120 ks from each telescope. The pulsar emission shows strong modulation below 2.5 keV with a single-peaked profile and a large pulsed fraction of 0.48 {+-} 0.12. Employing a magnetic, partially ionized hydrogen atmosphere model, we find that the observed pulse profile can be produced by a single hot spot of temperature 0.13 keV covering about one-third of the stellar surface, and we place an upper limit of 0.08 keV for an antipodal hot spot with the same area. The non-uniform surface temperature distribution could be the result of anisotropic heat conduction under a strong magnetic field, and a single-peaked profile seems common among high-B radio pulsars. For the associated remnant G292.2-0.5, its large diameter could be attributed to fast expansion in a low-density wind cavity, likely formed by a Wolf-Rayet progenitor, similar to two other high-B radio pulsars.

Ng, C.-Y.; Kaspi, V. M. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Ho, W. C. G. [School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom); Weltevrede, P. [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom); Bogdanov, S. [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Shannon, R. [CSIRO Astronomy and Space Sciences, Australia Telescope National Facility, Marsfield, NSW 2210 (Australia); Gonzalez, M. E., E-mail: ncy@physics.mcgill.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)

2012-12-10

36

PSR J1833-1034: Discovery of the Central Young Pulsar in the Supernova Remnant G21.5-0.9  

NASA Astrophysics Data System (ADS)

We have discovered the pulsar associated with the supernova remnant G21.5-0.9. PSR J1833-1034, with spin period P=61.8 ms and dispersion measure 169 cm-3 pc, is very faint, with pulse-averaged flux density of ~70 ?Jy at a frequency of 1.4 GHz, and was first detected in a deep search with the Parkes telescope. Subsequent observations with Parkes and the Green Bank Telescope have confirmed this detection and yield a period derivative P?=2.0210-13. These spin parameters imply a characteristic age ?c=4.8 kyr and a spin-down luminosity E?=3.31037 ergs s-1, the latter value exceeded only by the Crab pulsar among the rotation-powered pulsars known in our Galaxy. The pulsar has an unusually steep radio spectrum in the 0.8-2.0 GHz range, with power-law index ~3.0, and a narrow single-peaked pulse profile with FWHM of 0.04P. We have analyzed 350 ks of archival Chandra X-Ray Observatory HRC data and find a pointlike source of luminosity ~310-5E?, offset from the center of an elliptical region of size ~7''5'' and luminosity ~10-3E? within which likely lies the pulsar wind termination shock. We have searched for X-ray pulsations in a 30 ks HRC observation without success, deriving a pulsed fraction upper limit for a sinusoidal pulse shape of about 70% of the pulsar flux. We revisit the distance to G21.5-0.9 based on H I and CO observations, arguing that it is 4.7+/-0.4 kpc. We use existing X-ray and radio observations of the pulsar wind nebula, along with the measured properties of its engine and a recent detection of the supernova remnant shell, to argue that G21.5-0.9 and PSR J1833-1034 are much younger than ?c and likely their true age is <~1000 yr. In that case, the initial spin period of the pulsar was >~55 ms.

Camilo, F.; Ransom, S. M.; Gaensler, B. M.; Slane, P. O.; Lorimer, D. R.; Reynolds, J.; Manchester, R. N.; Murray, S. S.

2006-01-01

37

Multi-frequency observations of SNR J0453-6829 in the LMC; A composite supernova remnant with a pulsar wind nebula  

E-print Network

The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs) which can be investigated in detail with radio, optical and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical and X-ray images and investigated the energy spectra in the different parts of the remnant. Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index alpha_Core of -0.04+/-0.04, while in the rest of the S...

Haberl, F; Bozzetto, L M; Crawford, E J; Points, S D; Pietsch, W; De Horta, A Y; Tothill, N; Payne, J L; Sasaki, M

2012-01-01

38

Supernova Remnant SNR 0509 lithograph  

NSDL National Science Digital Library

This Hubble Space Telescope image shows what appears to be a delicate bubble of gas floating serenely in space. In actuality, the bubble is the visible remnant of a powerful supernova explosion called SNR 0509. The bubble was formed from gas being swept up by the expanding shock wave. In the accompanying educational activity, In Search of ... Supernova Remnants, students investigate supernova explosions and remnants through a level 1 inquiry activity using the images and text from the lithograph and other resources. A level 1 inquiry activity can help prepare students to become independent thinkers.

39

Supernova Remnants And GLAST  

SciTech Connect

It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs.With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

Slane, Patrick; /Harvard-Smithsonian Ctr. Astrophys.

2011-11-29

40

Supernova Remnants and GLAST  

E-print Network

It has long been speculated that supernova remnants represent a major source of cosmic rays in the Galaxy. Observations over the past decade have ceremoniously unveiled direct evidence of particle acceleration in SNRs to energies approaching the knee of the cosmic ray spectrum. Nonthermal X-ray emission from shell-type SNRs reveals multi-TeV electrons, and the dynamical properties of several SNRs point to efficient acceleration of ions. Observations of TeV gamma-ray emission have confirmed the presence of energetic particles in several remnants as well, but there remains considerable debate as to whether this emission originates with high energy electrons or ions. Equally uncertain are the exact conditions that lead to efficient particle acceleration. Based on the catalog of EGRET sources, we know that there is a large population of Galactic gamma-ray sources whose distribution is similar to that of SNRs. With the increased resolution and sensitivity of GLAST, the gamma-ray SNRs from this population will be identified. Their detailed emission structure, along with their spectra, will provide the link between their environments and their spectra in other wavebands to constrain emission models and to potentially identify direct evidence of ion acceleration in SNRs. Here I summarize recent observational and theoretical work in the area of cosmic ray acceleration by SNRs, and discuss the contributions GLAST will bring to our understanding of this problem.

Patrick Slane

2007-04-16

41

Plerionic supernova remnants  

NASA Astrophysics Data System (ADS)

Plerions represent ideal laboratories for the search for neutron stars, the study of their relativistic winds, and their interaction with their surrounding supernova ejecta and/or the interstellar medium. As well, they are widely believed to represent efficient engines for particle acceleration up to the knee of the cosmic ray spectrum (at about 1015 eV). Multi-wavelength observations from the radio to the highest TeV energies, combined with modelling, have opened a new window to study these objects, and particularly shed light on their intrinsic properties, diversity, and evolution. High-resolution X-ray observations are further revealing the structure and sites for shock acceleration. The missing shells in the majority of these objects remain puzzling, and the presence of plerions around highly magnetized neutron stars is still questionable. I review the current status and statistics of observations of plerionic supernova remnants (SNRs), highlighting combined radio and X-ray observations of a growing class of atypical, non Crab-like, plerionic SNRs in our Galaxy. I will also briefly describe the latest developments to our high-energy SNRs catalogue recently released to the community, and finally highlight the key questions to be addressed in this field with future high-energy missions, including Astro-H in the very near future.

Safi-Harb, Samar

2012-12-01

42

CHANDRA AND XMM-NEWTON STUDIES OF THE SUPERNOVA REMNANT G292.2-0.5 ASSOCIATED WITH THE PULSAR J1119-6127  

SciTech Connect

We present the first detailed imaging and spatially resolved spectroscopic study of the Galactic supernova remnant (SNR) G292.2-0.5, associated with the high-magnetic field radio pulsar (PSR) J1119-6127, using Chandra and XMM-Newton. The high-resolution X-ray images reveal a partially limb-brightened morphology in the west, with diffuse emission concentrated toward the interior of the remnant unlike the complete shell-like morphology observed at radio wavelengths. The spectra of most of the diffuse emission regions within the remnant are best described by a two-component thermal+non-thermal model. The thermal component is described by a plane-parallel, non-equilibrium ionization plasma model with a temperature kT ranging from 1.3{sup +0.3}{sub -0.2} keV in the western side of the remnant to 2.3{sup +2.9}{sub -0.5} keV in the east, a column density increasing from 1.0{sup +0.1}{sub -0.6} Multiplication-Sign 10{sup 22} cm{sup -2} in the west to 1.8{sup +0.2}{sub -0.4} Multiplication-Sign 10{sup 22} cm{sup -2} in the east, and a low ionization timescale ranging from (5.7{sup +0.8}{sub -0.7}) Multiplication-Sign 10{sup 9} cm{sup -3} s in the SNR interior to (3.6{sup +0.7}{sub -0.6}) Multiplication-Sign 10{sup 10} cm{sup -3} s in the western side-suggestive of expansion of a young remnant in a low-density medium. The spatial and spectral differences across the SNR are consistent with the presence of a dark cloud in the eastern part of the SNR, absorbing the soft X-ray emission, as also revealed by the optical image of that region. The spectra from some of the regions also show slightly enhanced metal abundances from Ne, Mg, and Si, hinting at the first evidence for ejecta heated by the reverse shock. Comparing our inferred metal abundances to core-collapse nucleosynthesis models yields, we estimate a high progenitor mass of {approx}30 M{sub Sun} suggesting a Type Ib/c supernova. We confirm the presence of non-thermal X-ray emission from regions close to the pulsar, with the emission characterized by a power-law model with a hard photon index similar to that seen in the compact pulsar wind nebula. We estimate an SNR age range between 4.2 kyr (free expansion phase) and 7.1 kyr (Sedov phase) at an assumed distance of 8.4 kpc, a factor of a few higher than the measured pulsar's age upper limit of 1.9 kyr.

Kumar, Harsha S.; Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Gonzalez, Marjorie E., E-mail: harsha@physics.umanitoba.ca, E-mail: samar@physics.umanitoba.ca, E-mail: gonzalez@phas.ubc.ca [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada)

2012-08-01

43

Neutron Stars in Supernova Remnants  

Microsoft Academic Search

I briefly summarize some facts and ideas concerning the presence of neutron\\u000astars in Supernova remnants. While sources similar to the Crab Nebula require\\u000athe presence of a central energetic object, shell-type remnants such as Cas A\\u000aare compatible with the presence of neutron stars releasing a weak relativistic\\u000awind.

Franco Pacini

1999-01-01

44

Supernovae, supernova remnants, and superbubbles  

NASA Technical Reports Server (NTRS)

Supernovae, supernova remmants, and superbubbles in the interstellar medium are reviewed, with an emphasis on infrared studies of these phenomena. Superbubbles are likely to be relevant for understanding such Galactic and extragalactic issues as the photoionization of gas in the Galactic halo, 'superwinds,' and the contribution of 'starbursts' to photoionization of the intergalactic medium.

Shull, J. Michael

1995-01-01

45

Discovery of a 105-ms X-ray Pulsar in Kesteven-79: On the Nature of Compact Central Objects in Supernova Remnants  

NASA Technical Reports Server (NTRS)

We report the discovery of 105-ms X-ray pulsations from the compact central object (CCO) in the supernova remnant \\snr\\ using data acquired with the {\\it Newton X-Ray Multi-Mirror Mission). Using two observations of the pulsar taken 6-days apart we derive an upper limit on its spin-down rate of $\\dot P < 9 \\times 10"{-14}$-s-${-l)$,a nd find no evidence for binary orbital motion. The implied energy loss rate is $\\dot E < 3 \\times 10A{36)$-ergs-s$A{-1)$, polar magnetic field strength is $B-{\\rm p) < 3 \\times 10A{12)$-G, and spin-down age is $\\tau > 18.5$-kyr. The latter exceeds the remnant's estimated age, suggesting that the pulsar was born spinning near its current period. The X-ray spectrum of \\psr\\ is best characterized as a blackbody of temperature $kT {BB) =, 0.43\\pm0.02$ keV, radius $R-{BB) \\approx 1.3$-km, and $I{\\rm bol) = 5.2 \\times 10A{33)$ ergs-sSA{-1)$ at $d = 7.1$-kpc. The sinusoidal light curve is modulated with a pulsed fraction of $>45\\%$, suggestive of a small hot spot on the surface of the rotating neutron star. The lack of a discernible pulsar wind nebula is consistent with an interpretation of \\psr\\ as a rotation-powered pulsar whose spin-down luminosity falls below the empirical threshold for generating bright wind nebulae, $\\dot E-{\\rm c) = 4 \\times 10A{36)$-ergs-sSA{-I)$. The age discrepancy suggests that its $\\dot E$ has always been below $\\dot E c$, perhaps a distinguishing property of the CCOs. Alternatively, the X-ray spectrum of \\psr\\ suggests a low-luminosity AXP, but the weak inferred $B-{\\rm p)$ field is incompatible with a magnetar theory of its X-ray luminosity. The ordinary spin parameters discovered from \\psr\\ highlight the inability of existing theories to explain the high luminosities and temperatures of CCO thermal X-ray spectra.

Gotthelf, E. V.; Halpern, J. P.; Seward, F. D.

2005-01-01

46

Radio Observations of Supernova Remnants  

E-print Network

Supernovae release an enormous amount of energy into the interstellar medium. Their remnants can observationally be traced up to several ten-thousand years. So far more than 230 Galactic supernova remnants (SNRs) have been identified in the radio range. Detailed studies of the different types of SNRs give insight into the interaction of the blast wave with the interstellar medium. Shock accelerated particles are observed, but also neutron stars left from the supernova explosion make their contribution. X-ray observations in conjunction with radio data constrain models of supernova evolution. A brief review of the origin and evolution of SNRs is given, which are compared with supernova statistics and observational limitations. In addition the morphology and characteristics of the different types of SNRs are described, including some recent results and illustrated by SNRs images mostly obtained with the Effelsberg 100-m telescope.

W. Reich

2002-08-28

47

On understanding the lives of dead stars : Supernova Remnant N103B, radio pulsar B1951+32, and the Rabbit  

E-print Network

Using the Chandra High Energy Transmission Grating Spectrometer, we observed the young Supernova Remnant N103B in the Large Magellanic Cloud as part of the Guaranteed Time Observation program. N103B has a small overall ...

Migliazzo, Joshua Marc, 1977-

2003-01-01

48

128A Pulsar Shot Out from a Supernova Explosion! The Chandra X-ray  

E-print Network

128A Pulsar Shot Out from a Supernova Explosion! The Chandra X-ray Observatory has seen a fast- moving pulsar escaping from a supernova remnant while spewing out a record-breaking jet. This is, to date, the longest object observed in the Milky Way galaxy. The jet is nearly 37 light years long! The pulsar is 60

Christian, Eric

49

Chandra Associates Pulsar and Historic Supernova  

NASA Astrophysics Data System (ADS)

SAN DIEGO -- Scientists using NASAs Chandra X-ray Observatory have found new evidence that a pulsar in the constellation of Sagittarius was created when a massive star exploded, witnessed by Chinese astronomers in the year 386 AD. If confirmed, this will be only the second pulsar to be clearly associated with a historic event. These results were presented today by Victoria Kaspi and Mallory Roberts of McGill University at the American Astronomical Society meeting. Also participating in the research were Gautum Vasisht from the Jet Propulsion Laboratory, Eric Gotthelf from Columbia University, Michael Pivovaroff from Therma-Wave, Inc., and Nobuyuki Kawai from the Institute of Physical and Chemical Research, Japan. The scientists used Chandra to locate the pulsar exactly at the geometric center of the supernova remnant known as G11.2-0.3. This location provides very strong evidence that the pulsar, a neutron star that is rotating 14 times a second, was formed in the supernova of 386 AD, and therefore has an age of 1615 years. "Determining the true ages of astronomical objects is notoriously difficult, and for this reason, historical records of supernovas are of great importance,"said Kaspi."In roughly the past 2,000 years, fewer than 10 reports of probable supernovae have been archived mostly by Asian astronomers. Of those handful, the remnant of 1054 AD, the Crab Nebula, was until now the only pulsar whose birth could be associated with a historic event - and, hence, the only neutron star that has a firm age." Between mid-April and mid-May in the year 386 AD, a young "guest star", presumably a supernova, was recorded by Chinese observers in the direction of the sky now known as the constellation of Sagittarius. In the 1970s, radio astronomers discovered an expanding nebula of gas and high-energy particles, called G11.2-0.3, that is believed to be the remnant of that explosion. In 1997, a team of X-ray astronomers used Japans ASCA satellite to discover a pulsar in the same area of the sky. Past attempts to identify the pulsar with G11.2-0.3, and hence the ancient Chinese observations, have been controversial. The location of the pulsar at the center of the remnant provides new evidence that it is associated with the remnant. Since pulsars are known to move rapidly away from where they are formed, a pulsar near the center of the remnant implies the system must be very young, since not enough time has elapsed for the pulsar to travel far from its birthplace. "We believe that the pulsar and the supernova remnant G11.2-0.3 are both likely to be left over from the explosion seen by the Chinese observers over 1600 years ago," said Roberts. "While this is exciting by itself, it also raises new questions about what we know about pulsars especially during their infancies." These questions follow from a discrepancy that arose when the ASCA team applied the present spin rate to current models to determine the pulsars estimated lifetime and compare it to the age of G11.2-0.3. The result was an age of roughly 24,000 years - far predating the birth year of 386 AD. To explain this contradiction, the Chandra team argues that this pulsar may have had approximately the same spin rate today as it did at its birth, as had been suggested by the ASCA data. If this is true, then it could have important implications for the conventional wisdom regarding pulsars, which, may be born spinning more slowly than has been thought. "We now have strong evidence that the standard age estimate for this pulsar is probably wrong, and it is much younger than previously believed," said Kaspi. "This, in turn, suggests that other standard pulsar age estimates may be wrong as well, and this has important implications for the population as a whole." In addition to these results, the Chandra observations of G11.2-0.3 have, for the first time, revealed the bizarre appearance of the pulsar wind nebula (also known as "plerions") at the center of the supernova remnant. Its rough cig

2001-01-01

50

Variability of the High Magnetic Field X-Ray Pulsar PSR J1846-0258 Associated with the Supernova Remnant Kes 75 as Revealed by the Chandra X-Ray Observatory  

NASA Astrophysics Data System (ADS)

We present results from the archival Chandra observations of the 0.3 s X-ray pulsar PSR J1846-0258 associated with the supernova remnant (SNR) Kes 75. The pulsar has the highest spin-down luminosity (? = 8.3 1036 ergs s-1) among all the high magnetic field pulsars (HBPs) and has been classified as a Crab-like pulsar despite its magnetic field (5 10 13 G) being above the quantum critical field. It is the only HBP described by a nonthermal Crab-like spectrum, powering a bright pulsar wind nebula (PWN). Our spectroscopic study shows evidence of spectral softening (photon index ? = 1.32+0.08-0.09 to 1.97+0.05-0.07) and temporal brightening [unabsorbed flux Funabs = (4.3 +/- 0.2) 10-12 to 2.7+0.1-0.2 10-11 ergs cm-2 s-1] of the pulsar by ~6 times from 2000 to 2006. The 0.5-10 keV luminosity of the pulsar at the revised distance of 6 kpc has also increased from LX = (1.85 +/- 0.08) 1034 to 1.16+0.03-0.07 1035 ergs s-1, and the X-ray efficiency increased from 0.2% +/- 0.01% to 1.4+0.04-0.08%. The observed X-ray brightening and softening of the pulsar suggests for the first time that this HBP is revealing itself as a magnetar.

Kumar, Harsha Sanjeev; Safi-Harb, Samar

2008-05-01

51

Supernovae and supernova remnants at low frequencies  

NASA Technical Reports Server (NTRS)

The importance of low-frequency observations of the intrinsic radio emission from supernovae and their remnants is discussed, with special attention given to an example of a peculiarity at low frequencies of the 38-MHz 'flare' observed from Cas A in the mid-1970s. It is suggested that, for explosions from supernovae in a low-density wind, it may be possible to follow the absorption over a large range of shock front radii. Absorption local to the remnants can occur in H II regions created by the supernovae or their progenitors and in the cooling layers of radiative shock fronts, or in the ionized interstellar medium. Observations of emission as well as of absorption are necessary to determine the location of the ionized gas.

Chevalier, Roger A.

1990-01-01

52

X-RAY OBSERVATIONS OF THE SUPERNOVA REMNANT CTB 87 (G74.9+1.2): AN EVOLVED PULSAR WIND NEBULA  

SciTech Connect

Pulsar wind nebulae (PWNe) studies with the Chandra X-Ray Observatory have opened a new window to address the physics of pulsar winds, zoom on their interaction with their hosting supernova remnant (SNR) and interstellar medium, and identify their powering engines. We here present a new 70 ks, plus an archived 18 ks, Chandra ACIS observation of the SNR CTB 87 (G74.9+1.2), classified as a PWN with unusual radio properties and poorly studied in X-rays. We find that the peak of the X-ray emission is clearly offset from the peak of the radio emission by {approx}100'' and located at the southeastern edge of the radio nebula. We detect a point source-the putative pulsar-at the peak of the X-ray emission and study its spectrum separately from the PWN. This new point source, CXOU J201609.2+371110, is surrounded by a compact nebula displaying a torus-like structure and possibly a jet. A more extended diffuse nebula is offset from the radio nebula, extending from the point source to the northwest for {approx}250''. The spectra of the point source, compact nebula, and extended diffuse nebula are all well described by a power-law model with a photon index of 1.1 (0.7-1.6), 1.2 (0.9-1.4), and 1.7 (1.5-1.8), respectively, for a column density N{sub H} = 1.38 (1.21-1.57) Multiplication-Sign 10{sup 22} cm{sup -2} (90% confidence). The total X-ray luminosity of the source is {approx}1.6 Multiplication-Sign 10{sup 34} erg s{sup -1} at an assumed distance of 6.1 kpc, with {approx}2% and 6% contribution from the point source and compact nebula, respectively. The observed properties suggest that CTB 87 is an evolved ({approx}5-28 kyr) PWN, with the extended radio emission likely a ''relic'' PWN, as in Vela-X and G327.1-1.1. To date, however, there is no evidence for thermal X-ray emission from this SNR, and the SNR shell is still missing, suggesting expansion into a low-density medium (n{sub 0} < 0.2 D{sup -1/2}{sub 6.1} cm{sup -3}), likely caused by a stellar wind bubble blown by the progenitor star.

Matheson, H.; Safi-Harb, S. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Kothes, R., E-mail: matheson@physics.umanitoba.ca, E-mail: samar@physics.umanitoba.ca, E-mail: roland.kothes@nrc-cnrc.gc.ca [Dominion Radio Astrophysical Observatory, National Research Council Herzberg, P.O. Box 248, Penticton, British Columbia, V2A 6J9 (Canada)

2013-09-01

53

X-Ray Observations of the Supernova Remnant CTB 87 (G74.9+1.2): An Evolved Pulsar Wind Nebula  

NASA Astrophysics Data System (ADS)

Pulsar wind nebulae (PWNe) studies with the Chandra X-Ray Observatory have opened a new window to address the physics of pulsar winds, zoom on their interaction with their hosting supernova remnant (SNR) and interstellar medium, and identify their powering engines. We here present a new 70 ks, plus an archived 18 ks, Chandra ACIS observation of the SNR CTB 87 (G74.9+1.2), classified as a PWN with unusual radio properties and poorly studied in X-rays. We find that the peak of the X-ray emission is clearly offset from the peak of the radio emission by ~100'' and located at the southeastern edge of the radio nebula. We detect a point sourcethe putative pulsarat the peak of the X-ray emission and study its spectrum separately from the PWN. This new point source, CXOU J201609.2+371110, is surrounded by a compact nebula displaying a torus-like structure and possibly a jet. A more extended diffuse nebula is offset from the radio nebula, extending from the point source to the northwest for ~250''. The spectra of the point source, compact nebula, and extended diffuse nebula are all well described by a power-law model with a photon index of 1.1 (0.7-1.6), 1.2 (0.9-1.4), and 1.7 (1.5-1.8), respectively, for a column density N H = 1.38 (1.21-1.57) 1022 cm-2 (90% confidence). The total X-ray luminosity of the source is ~1.6 1034 erg s-1 at an assumed distance of 6.1 kpc, with ~2% and 6% contribution from the point source and compact nebula, respectively. The observed properties suggest that CTB 87 is an evolved (~5-28 kyr) PWN, with the extended radio emission likely a "relic" PWN, as in Vela-X and G327.1-1.1. To date, however, there is no evidence for thermal X-ray emission from this SNR, and the SNR shell is still missing, suggesting expansion into a low-density medium (n_0 < 0.2 D^{-1/2}_{6.1} cm-3), likely caused by a stellar wind bubble blown by the progenitor star.

Matheson, H.; Safi-Harb, S.; Kothes, R.

2013-09-01

54

Magnetohydrodynamic turbulence in supernova remnants  

E-print Network

We present estimates of the angular power spectra of the synchrotron radiation intensity fluctuations at 6 and 20 cm for the shell type supernova remnant Cas A and the filled-centre Crab supernova remnant. We find that the intensity fluctuations of both sources have a power law power spectrum with index -3.24 +/- 0.03. This power law power spectrum is consistent with the magnetohydrodynamic turbulence in the synchrotron emitting plasma. For Cas A, there is a break in the power spectrum and the power law index changes from -3.2 to -2.2 at large angular scale. This transition occurs at an angular scale that corresponds to the shell thickness of Cas A. We interpret this as a transition from three dimensional turbulence to two dimensional turbulence on scales that are respectively smaller and larger than the shell thickness.

Nirupam Roy; Somnath Bharadwaj; Prasun Dutta; Jayaram N. Chengalur

2009-07-23

55

Identifying Elements in Supernova Remnants  

NSDL National Science Digital Library

This activity has students use X-ray line data to identify elements contained in supernova remnants. In groups of 2 or more, they will be given several X-ray spectra from the ASCA X-ray satellite and will be asked to determine what elements are present, using a chart listing elements and the energies of their emission lines. Following a class discussion of their results, they will be given ASTRO-E spectra of the same sources and asked to determine which elements are present. Finally, they will be given spectra from Constellation-X and asked to determine what elements are present. Students will then compare and contrast Supernova Remnant Spectral Data from the three different X-ray observatories as a class. This site contains links to the simulated spectra, chart, student worksheet, and instructions.

56

Environmental impact of Supernova Remnants  

E-print Network

The explosion of a supernovae (SN) represents the sudden injection of about 10^51 ergs of thermal and mechanical energy in a small region of space, causing the formation of powerful shock waves that propagate through the interstellar medium at speeds of several thousands of km/s. These waves sweep, compress and heat the interstellar material that they encounter, forming the supernova remnants. Their evolution over thousands of years change forever, irreversibly, not only the physical but also the chemical properties of a vast region of space that can span hundreds of parsecs. This contribution briefly analyzes the impact of these explosions, discussing the relevance of some phenomena usually associated with SNe and their remnants in the light of recent theoretical and observational results.

Dubner, Gloria

2015-01-01

57

Distance Determination to the Crab-Like Pulsar Wind Nebula G54.1+0.3 and the Search for its Supernova Remnant Shell  

NASA Astrophysics Data System (ADS)

We discovered a large-scale shell G53.9+0.2 around the Crab-like pulsar wind nebula (PWN) G54.1+0.3 with 1420 MHz continuum Very Large Array observations. This is confirmed by a new infrared (IR) image at 8 ?m from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire project, which reveals an intriguing IR shell just surrounding the large radio shell. We analyze the 21 cm H I absorption spectra and 13CO emission spectra toward PWN G54.1+0.3 and bright sources on both radio and IR shells. Continuous H I absorption up to the tangent point and absence of negative H I absorption features imply that PWN G54.1+0.3 has a distance beyond the tangent point but within the solar circle, i.e., 4.5-9 kpc. G54.1+0.3 is likely at a distance of sime6.2 kpc due to the morphological association of the PWN with a CO molecular cloud at a velocity of sime53 km s-1, as revealed by high-resolution 13CO images. Based on the H I absorption spectrum and recombination line velocity (sime40 km s-1) of the bright H II region G54.09-0.06, which is on the IR shell, the IR shell is likely located at a distance of sime7.3 kpc, which is also the distance of the associated large-scale radio shell. At this distance, the radio shell has a radius of ~30 pc. The radio shell may be thermal and lack IR emission due to dust destruction, or it may be nonthermal and part of a newly found old supernova remnant. In either case, it is located at a distance different from PWN G54.1+0.3.

Leahy, Denis A.; Tian, Wenwu; Wang, Q. D.

2008-10-01

58

Observing Supernovae and Supernova Remnants with JWST  

NASA Astrophysics Data System (ADS)

The James Webb Space Telescope (JWST) will enable near- and mid-infrared studies of supernovae (SN) and supernova remnants (SNR) in the Milky Way and galaxies throughout the local universe and to high redshift. JWST's instrumentation provides imaging, coronography, and spectroscopy (R<3000) over the wavelength range 1-29 microns. The unprecedented sensitivity and angular resolution will enable spectroscopic study of new and recent supernovae, including molecule and dust formation, in galaxies at least out to 30 Mpc, and imaging to much greater distances. The Target of Opportunity response time can be as short as 48 hours, enabling quick follow-up observations of important SN events. JWST will be ideal for the study of Galactic and Magellanic Clouds supernova remnants, particularly young remnants with hot dust. Its high angular resolution (0.07" at 2 microns, 0.7" at 20 microns) will allow direct comparison between the IR, optical, and X-ray morphologies, identifying sites of dust emission in both the ejecta and the shocked ISM unresolved by previous IR telescopes. There is a rich spectrum of atomic lines (H, He I, [Si I], [Fe II], [Ni I-III], [Co II-III], [S III-IV], [Ar II-III], [Ne II, III, V], [O IV]) and molecules (CO, SiO, H2) of importance for SN and SNR studies. JWST is a large aperture (6.5m), cryogenic, infrared-optimized space observatory under construction by NASA, ESA, and CSA for launch in 2018. The JWST observatory will be placed in an Earth-Sun L2 orbit by an Ariane 5 launch vehicle provided by ESA. The observatory is designed for a 5-year prime science mission, with consumables for 10 years of science operations. The first call for proposals for JWST observations will be released in 2017.

Sonneborn, George; Temim, Tea; Williams, Brian J.; Blair, William P.

2015-01-01

59

Neutron Stars in Supernova Remnants and Beyond  

E-print Network

We discuss a concept of off-centred cavity supernova explosion as applied to neutron star/supernova remnant associations and show how this concept could be used to preclude the anti-humane decapitating the Duck (G5.4-1.2 + G5.27-0.9) and dismembering the Swan (Cygnus Loop), as well as to search for a stellar remnant associated with the supernova remnant RCW86.

V. V. Gvaramadze

2002-12-26

60

Molecular Environments of Supernova Remnants  

NASA Astrophysics Data System (ADS)

There are about 70 Galactic supernova remnants (SNRs) that are now confirmed or suggested to be in physical contact with molecular clouds (MCs) with six kinds of evidence of multiwavelength observations. Recent detailed CO-line spectroscopic mappings of a series of SNRs reveal them to be in cavities of molecular gas, implying the roles the progenitors may have played. We predict a linear correlation between the wind bubble sizes of main-sequence OB stars in a molecular environment and the stellar masses and discuss its implication for supernova progenitors. The molecular environments of SNRs can serve as a good probe for the ?-rays arising from the hadronic interaction of the accelerated protons, and this paper also discusses the ?-ray emission from MCs illuminated by diffusive protons that escape from SNR shocks.

Chen, Yang; Jiang, Bing; Zhou, Ping; Su, Yang; Zhou, Xin; Li, Hui; Zhang, Xiao

2014-01-01

61

Circumstellar Nebulae in Young Supernova Remnants  

E-print Network

Supernovae descendent from massive stars explode in media that have been modified by their progenitors' mass loss and UV radiation. The supernova ejecta will first interact with the circumstellar material shed by the progenitors at late evolutionary stages, and then interact with the interstellar material. Circumstellar nebulae in supernova remnants can be diagnosed by their small expansion velocities and high [N II]/H$\\alpha$ ratios. The presence of circumstellar nebulae appears ubiquitous among known young supernova remnants. These nebulae can be compared to those around evolved massive stars to assess the nature of their supernova progenitors. Three types of archeological artifacts of supernova progenitors have been observed in supernovae and/or young supernova remnants: (1) deathbed ejecta, (2) circumstellar nebulae, and (3) interstellar bubbles. Examples of these three types are given.

Y. -H. Chu

2000-12-29

62

A Compact Central Object in the Supernova Remnant Kes 79  

E-print Network

A Chandra X-ray observation has detected an unresolved source at the center of the supernova remnant Kes 79. The best single-model fit to the source spectrum is a blackbody with an X-ray luminosity Lx (0.3-8.0 keV) = 7 x 10^{33} ergs s^{-1}. There is no evidence for a surrounding pulsar wind nebula. There are no cataloged counterparts at other wavelengths, but the absorption is high. The source properties are similar to the central source in Cas A even though the Kes 79 remnant is considerably older.

F. D. Seward; P. O. Slane; R. K. Smith; M. Sun

2002-10-22

63

HIGH-ENERGY EMISSION FROM THE COMPOSITE SUPERNOVA REMNANT MSH 15-56  

E-print Network

MSH 15-56 (G326.31.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that ...

Temim, Tea

64

Generating Pulsar Spin in Supernovae  

Microsoft Academic Search

Using three-dimensional hydrodynamics simulations, we have identified a robust instability of the stalled accretion shock in core-collapse supernovae that is able to generate a strong rotational flow in the vicinity of the accreting proto-neutron star (PNS). Sufficient angular momentum is deposited on the PNS to generate a final neutron star spin period consistent with observations of radio pulsars, even beginning

John M. Blondin; A. Mezzacappa

2006-01-01

65

Gamma rays from supernova remnants  

NASA Astrophysics Data System (ADS)

The recent galactic plane surveys with space- and ground-based detectors revealed a number of high and very-high energy ?-ray sources associated with young and middle-aged supernova remnants (SNRs). These results imply effective production of relativistic particles, most likely through the process of diffusive shock acceleration. The interpretation of ?-ray data from several prominent representatives of young SNRs within the so-called hadronic models demands hard proton spectra extending to 100 TeV, and total energy released in accelerated protons and ions WCR?1050 erg. This can be treated as a support of the SNR paradigm of galactic cosmic rays. However, the hadronic models are not free of pitfalls, and pose in fact non-trivial challenges. Moreover, in many cases ?-ray data can be successfully explained also by the inverse Compton scattering of directly accelerated electrons. Future deep spectroscopic and morphological studies of SNRs with the planned Cherenkov Telescope Array (CTA) over four decades in energy, from approximately 30 GeV to 300 TeV, promise a breakthrough regarding the identification of radiation mechanisms. The extension of studies beyond the shells of SNRs will be another important objective aimed at the extraction of information about the highest energy particles which have left remnants at the early epochs of their evolution. These particles, which potentially carry an answer to a key question whether SNRs operate as PeVatrons, can be traced via ?-ray emission outside the remnants. Finally, the expected significant increase of the number of ?-ray emitting SNRs by CTA should allow compelling population studies - a key issue for the proof of the SNR origin of galactic cosmic rays.

Aharonian, Felix A.

2013-03-01

66

Supernova Remnants & Pulsar Wind Nebulae  

E-print Network

University) Jeonghee Rho (IPAC, Caltech) Jacco Vink (Astronomical Inst. University of Utrecht) Local: THEORY AND OBSERVATIONS CHAIR: ROGER CHEVALIER 1:30-2:00 Invited Talk: Elena Amato PWNe and Relativistic

67

Luminous stars in galactic supernova remnants  

NASA Technical Reports Server (NTRS)

It is shown that luminous stars should be expected in the vicinity of supernova remnants. Luminous stars within the maximum optical areas of supernova remnants are tabulated from catalogs, and an excitation parameter is correlated with the spectral classification of such stars when their UV flux excites H II regions to produce nebular thermal bremsstrahlung. The correlations indicate that the presence of a ZAMS star of type 08 to 05 is necessary to produce thermal bremsstrahlung equal to the observed flux density at 1 GHz. Optical components of seven other supernova remnants are discussed, and it is concluded that gross uncertainties in the distance moduli of both stars and supernova remnants prevent any associations from being made.

Johnson, H. M.

1975-01-01

68

Synthesis observations of southern supernova remnants  

Microsoft Academic Search

The synthesis telescopes at Fleurs and Molonglo have been used to map 50 supernova remnants. Additional specialized software to process the maps has been developed, and Parkes observations have been used to supply short spacing information missing from the maps.

D. K. Milne; J. L. Caswell; R. F. Haynes; M. J. Kesteven; K. J. Wellington; R. S. Roger; J. D. Bunton

1985-01-01

69

Synthesis observations of southern supernova remnants  

NASA Astrophysics Data System (ADS)

The synthesis telescopes at Fleurs and Molonglo have been used to map 50 supernova remnants. Additional specialized software to process the maps has been developed, and Parkes observations have been used to supply short spacing information missing from the maps.

Milne, D. K.; Caswell, J. L.; Haynes, R. F.; Kesteven, M. J.; Wellington, K. J.; Roger, R. S.; Bunton, J. D.

70

Stellar masers, circumstellar envelopes, and supernova remnants  

E-print Network

This paper reviews recent advances in the study or circumstellar masers and masers found toward supernova remnants. The review is organized by science focus area, including the astrophysics of extended stellar atmospheres, stellar mass-loss processes and outflows, late-type evolved stellar evolution, stellar maser excitation and chemistry, and the use of stellar masers as independent distance estimators. Masers toward supernova remnants are covered separately. Recent advances and open future questions in this field are explored.

Athol J. Kemball

2007-05-15

71

Synthesis surveys of southern supernova remnants  

Microsoft Academic Search

A report is presented detailing observations of supernova remnants (SNRs) with the Fleurs and Molonglo synthesis radio telescopes. Fifty-four remnants have been mapped with at least one of these instruments, eleven with both. Approximately half of the maps have been published and a key to these publications is given.

D. K. Milne; J. L. Caswell; R. F. Haynes; M. J. Kesteven; K. J. Wellington

1987-01-01

72

Synthesis surveys of southern supernova remnants  

NASA Astrophysics Data System (ADS)

A report is presented detailing observations of supernova remnants (SNRs) with the Fleurs and Molonglo synthesis radio telescopes. Fifty-four remnants have been mapped with at least one of these instruments, eleven with both. Approximately half of the maps have been published and a key to these publications is given.

Milne, D. K.; Caswell, J. L.; Haynes, R. F.; Kesteven, M. J.; Wellington, K. J.

73

Core-collapse supernova remnants and interactions with their surroundings  

NASA Astrophysics Data System (ADS)

This thesis examines three core-collapse supernova remnants (SNR)---the Cygnus Loop in the Milky Way and 0453-68.5 and 0540-69.3 in the Large Magellanic Cloud---of varying ages and in varying states of interaction with the surrounding interstellar medium (ISM), using X-ray imaging spectroscopy with Chandra and supplemental data from other wavelengths. We use results from our analysis to address three main questions. First, we examine the applicability of the common Sedov-Taylor adiabatic blast wave model to core-collapse supernovae. Second, we determine the elemental abundances around the shell of these supernova remnants to determine if the use of SNRs as a gauge of abundances in the ISM is justified. Finally, we examine the pulsar wind nebulae (PWNe) in 0453-68.5 and 0540-69.3 and search for evidence of interaction between these PWNe and their immediate surroundings. We see highly inhomogeneous ISM surrounding all three surveyed SNRs, contrary to the key assumption in the Sedov-Taylor model of a uniform surrounding medium. In all three studied SNRs, we find that shock speeds are dependent on the density of the surrounding material. As subsidiary results, we also find depleted elemental abundances of oxygen, magnesium, and silicon, relative to typical ISM, around all three studied supernova remnants. Although this subsidiary result is not conclusive, we believe that it merits a followup study. In 0540-69.3 and 0453-68.5, which contain central pulsars, we find that the explosion directionality, which can be inferred from the pulsar's proper motion relative to the SNR, is not related to the morphology of the SNR itself. We conclude from this that the asymmetric shapes common in core-collapse supernova remnants can be more a function of the complex environments surrounding the progenitors of core-collapse supernovae than of the supernova explosions themselves. Finally, we see that the PWN in 0453-68.5 shows signs of having mixed with the surrounding thermal- emitting material, while the PWN in 0540-69.3 appears to have not mixed with or interacted with the surrounding SNR material to any substantial degree. We believe that this result may indicate that the degree of interaction between a PWN and its surroundings is dependent on age and possibly shell morphology, although further study is needed.

Brantseg, Thomas Felton

74

X-ray spectroscopy of supernova remnants  

NASA Astrophysics Data System (ADS)

The information which can be obtained from X-ray spectroscopy of supernova remnants is considerd. The fitting of X-ray detector counts to models of the incident spectrum is discussed, and the types of thermal emission models generally employed are presented, including the power law, black body, and thermal bremsstrahlung models of the continua and models of the emission of a hot, optically thin plasma in collisional equilibrium. Observations of 12 supernova remnants made with the Solid State Spectrometer on board the Einstein Observatory are reported, and metal abundances inferred from the lines of the eight remnants showing thermal spectra are summarized. Questions raised by the failure to observe the overabundance of Fe predicted by stellar evolution and hydrodynamic modeling are discussed, and the need to develop more detailed models of the conditions in a supernova remnant in order to interpret the X-ray spectra is noted.

Szymkowiak, A. E.

75

Supernova remnant S147 and its associated neutron star(s)  

E-print Network

The supernova remnant S147 harbors the pulsar PSR J0538+2817 whose characteristic age is more than an order of magnitude greater than the kinematic age of the system (inferred from the angular offset of the pulsar from the geometric center of the supernova remnant and the pulsar proper motion). To reconcile this discrepancy we propose that PSR J0538+2817 could be the stellar remnant of the first supernova explosion in a massive binary system and therefore could be as old as its characteristic age. Our proposal implies that S147 is the diffuse remnant of the second supernova explosion (that disrupted the binary system) and that a much younger second neutron star (not necessarily manifesting itself as a radio pulsar) should be associated with S147. We use the existing observational data on the system to suggest that the progenitor of the supernova that formed S147 was a Wolf-Rayet star (so that the supernova explosion occurred within a wind bubble surrounded by a massive shell) and to constrain the parameters of the binary system. We also restrict the magnitude and direction of the kick velocity received by the young neutron star at birth and find that the kick vector should not strongly deviate from the orbital plane of the binary system.

V. V. Gvaramadze

2006-04-08

76

Guiding the Way to Gamma-Ray Sources: X-ray Studies of Supernova Remnants  

E-print Network

Supernova remnants have long been suggested as a class of potential counterparts to unidentified gamma-ray sources. The mechanisms by which such gamma-rays can arise may include emission from a pulsar associated with a remnant, or a variety of processes associated with energetic particles accelerated by the SNR shock. Imaging and spectral observations in the X-ray band can be used to identify properties of the remnants that lead to gamma-ray emission, including the presence of pulsar-driven nebulae, nonthermal X-ray emission from the SNR shells, and the interaction of SNRs with dense surrounding material.

Patrick Slane

2001-04-21

77

Supernova Remnant in 3-D  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for the movie

For the first time, a multiwavelength three-dimensional reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A, or Cas A, the result of an explosion approximately 330 years ago, uses data from several telescopes: X-ray data from NASA's Chandra X-ray Observatory, infrared data from NASA's Spitzer Space Telescope and optical data from the National Optical Astronomy Observatory 4-meter telescope at Kitt Peak, Ariz., and the Michigan-Dartmouth-MIT 2.4-meter telescope, also at Kitt Peak. In this visualization, the green region is mostly iron observed in X-rays. The yellow region is a combination of argon and silicon seen in X-rays, optical, and infrared including jets of silicon plus outer debris seen in the optical. The red region is cold debris seen in the infrared. Finally, the blue reveals the outer blast wave, most prominently detected in X-rays.

Most of the material shown in this visualization is debris from the explosion that has been heated by a shock moving inwards. The red material interior to the yellow/orange ring has not yet encountered the inward moving shock and so has not yet been heated. These unshocked debris were known to exist because they absorb background radio light, but they were only recently discovered in infrared emission with Spitzer. The blue region is composed of gas surrounding the explosion that was heated when it was struck by the outgoing blast wave, as clearly seen in Chandra images.

To create this visualization, scientists took advantage of both a previously known phenomenon the Doppler effect and a new technology that bridges astronomy and medicine. When elements created inside a supernova, such as iron, silicon and argon, are heated they emit light at certain wavelengths. Material moving towards the observer will have shorter wavelengths and material moving away will have longer wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.

The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.

This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.

High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these structures, but their orientation and position with resp

2009-01-01

78

Isothermal blast wave model of supernova remnants  

NASA Technical Reports Server (NTRS)

The validity of the 'adiabatic' assumption in supernova-remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast-wave model.

Solinger, A.; Buff, J.; Rappaport, S.

1975-01-01

79

Evolution of multiple supernova remnants  

NASA Astrophysics Data System (ADS)

Heating of the interstellar medium (ISM) by multiple supernova (SN) explosions is at the heart of producing galaxy-scale outflows in starburst galaxies. Standard models of outflows assume a high efficiency of SNe in heating the gas to X-ray emitting temperatures and filling the central region of starburst with hot gas, in order to launch vigorous outflows. We use hydrodynamical simulations to study the efficiency of multiple SNe in heating the ISM and filling the volume with gas of high temperatures. We argue that it is important for SN remnants to have a large filling factor and a large heating efficiency. For this, they have to be clustered in space and time, and keep exploding until the hot gas percolates through the whole region, in order to compensate for the radiative loss. In the case of a limited number of SNe, we find that although the filling factor can be large, the heating efficiency declines after reaching a large value. In the case of a continuous series of SNe, the hot gas (T ? 3 106 K) can percolate through the whole region after the total volume filling factor reaches a threshold of 0.3. The efficiency of heating the gas to X-ray temperatures can be ?0.1 after this percolation epoch, which occurs after a period of ?10 Myr for a typical starburst SN rate density of ?SN ? 10-9 pc-3 yr-1 and gas density of n ? 10 cm-3 in starburst nuclei regions. This matches the recent observations of a time delay of similar order between the onset of star formation and galactic outflows. The efficiency to heat gas up to X-ray temperatures (?106.5 K) roughly scales as ? _SN^{0.2} n^{-0.6}. For a typical SN rate density and gas density in starburst nuclei, the heating efficiency is 0.15, also consistent with previous interpretations from X-ray observations. We discuss the implications of our results with regard to observational diagnostics of ionic ratios and emission measures in starburst nuclei regions.

Vasiliev, Evgenii O.; Nath, Biman B.; Shchekinov, Yuri

2015-01-01

80

Imagery and spectroscopy of supernova remnants and H-2 regions  

NASA Technical Reports Server (NTRS)

Research activities relating to supernova remnants were summarized. The topics reviewed include: progenitor stars of supernova remnants, UV/optical/radio/X-ray imagery of selected regions in the Cygnus Loop, UV/optical spectroscopy of the Cygnus Loop spur, and extragalactic supernova remnant spectra.

Dufour, R. J.

1984-01-01

81

43A Distant Supernova Remnant Discovered These delicate wisps of gas make up an object known as supernova remnant SNR  

E-print Network

43A Distant Supernova Remnant Discovered These delicate wisps of gas make up an object known as supernova remnant SNR 0519. The thin, blood-red shells are actually the remnants from when an unstable star exploded violently as a supernova around 600 years ago. SNR 0519 is located over 150,000 light-years from

Christian, Eric

82

Ultra High Energy Neutrinos from Supernova Remnants  

E-print Network

In this paper we discuss possible ultra high energy ($\\ge$ TeV) neutrino emission from Supernova Remnants (SNRs), specifically the hadronic gamma ray production models. Recent very high energy (VHE) $\\gamma$ ray observation from SNRs is the main motivation behind this study.

Mou Roy

1999-01-15

83

The Cygnus Loop: An Older Supernova Remnant.  

ERIC Educational Resources Information Center

Describes the Cygnus Loop, one of brightest and most easily studied of the older "remnant nebulae" of supernova outbursts. Discusses some of the historical events surrounding the discovery and measurement of the Cygnus Loop and makes some projections on its future. (TW)

Straka, William

1987-01-01

84

HI Study of Southern Galactic Supernova Remnants  

E-print Network

We briefly summarize the survey of HI 21 cm emission lines to search for shocked atomic gas associated with Galactic supernova remnants (SNRs) in the southern sky. For G347.3-0.5, we discuss the distance to the SNR and the implications of the HI results.

Bon-Chul Koo; Ji-hyun Kang; Naomi McClure-Griffiths

2003-11-06

85

Autopsy of the Supernova Remnant Cassiopeia A  

NASA Astrophysics Data System (ADS)

Three-dimensional kinematic reconstructions of optically emitting ejecta in the young Galactic supernova remnant Cassiopeia A (Cas A) are discussed. The reconstructions encompass the remnant's faint outlying ejecta knots, including the exceptionally high-velocity NE and SW streams of debris often referred to as `jets'. The bulk of Cas A's ejecta are arranged in several circular rings with diameters between approximately 30'' (0.5 pc) and 2' (2 pc). We suggest that similar large-scale ejecta rings may be a common phenomenon of young core-collapse remnants and may explain lumpy emission line profile substructure sometimes observed in spectra of extragalactic core-collapse supernovae years after explosion. A likely origin for these large ejecta rings is post-explosion input of energy from plumes of radioactive 56Ni-rich ejecta that rise, expand, and compress non-radioactive material to form bubble-like structures.

Milisavljevic, Dan; Fesen, Robert A.

2014-01-01

86

Supernovae and supernova remnants at high energies  

NASA Technical Reports Server (NTRS)

The physical phenomena that are observable with X- and gamma-ray observations of supernovae are discussed with respect to possible high-energy astrophysics experiments. Prompt photospheric emission and its echo are discussed, supernova radioactivity and neutron star effects are examined, and circumstellar and interstellar interaction are reviewed. The primary uncertainties are found to be the hardening of the spectrum by non-LTE effects and the amount of absorption of the radiation from the initial soft X-ray burst. The radioactivity in supernovae is theorized to lead to gamma-ray lines and continuum emission unless the event is low-mass type II. Gamma-ray observations are proposed to examine the efficiency of particle acceleration, and high-resolution spectroscopy can provide data regarding ionization, temperature, composition, and velocities of the X-ray-emitting gas.

Chevalier, Roger A.

1990-01-01

87

The Rediscovery of the Antlia Supernova Remnant  

NASA Astrophysics Data System (ADS)

While undertaking a survey of velocity-resolved diffuse optical emission from the [S II] 6716 A line with the Wisconsin H-alpha Mapper, we have rediscovered the Antlia Supernova remnant, a 26 degree diameter remmant near the Gum Nebula that was originally detected in SHASSA (Southern H-alpha Sky Survey Atlas) by P. McCullough in 2002. The original discovery showed this remnant was associated with keV X-ray emission in the ROSAT All-Sky Survey, and argued that Antlia was potentially the closest remnant to the Sun. We will present an analysis of the H-alpha and [S II] lines in this direction: the ratio of these lines indicate the shell is consistent with being a supernova remnant and the velocities allow us to constrain its age. We discuss this remnant in the context of the evolution of the entire Gum Nebula region, noting that its proximity and age make it possible to search for geochemical evidence of this remnant on Earth. This work was supported by the National Science Foundation's REU program through NSF Award AST-1004881.

Orchard, Alexander; Benjamin, Robert A.; Gostisha, Martin; Haffner, L. Matthew; Hill, Alex S.; Barger, Kathleen

2015-01-01

88

"Suzaku Highlight Results on Supernova Remnants"  

NASA Technical Reports Server (NTRS)

Highlights of the early Suzaku (formerly Astro-E2) observations of supernova remnants are presented. Suzaku offers unique capabilities for the study of supernova remnants. The unprecedented combination of imaging and spectral resolution below 1 keV in the X-ray Imaging Spectrometer (XIS) makes possible mapping of C, N and O abundances in Galactic remnants of all ages. The first detection of carbon lines in the Cygnus Loop and mapping of the O VII to O VIII ratio in SN 1006 demonstrate this capability. The XIS sensitivity to soft, low surface brightness emission is exemplified by spectroscopy in the 0.3-1.0 keV band of the North Polar Spur and other Galactic ISM structures. Such observations make possible inferences about plasma conditions and abundances. The sensitivity above 6 keV via a combination of the XIS (below 10 keV) and the Hard X-ray Detector (above 10 keV) allows broad band (2-40 keV) spectroscopy and mapping of extended remnants with hard emission components. These components are generally associated with sites of particle acceleration, and measuring their spectral shape potentially provides information about the TeV electron population and its acceleration and energy loss mechanisms. Examples of such remnants observed by Suzaku are the non-thermal emission dominated remnants RX J1713.7-3946 and RX J0852.0-4622, for which flux beyond 30 keV has been detected. The status of the mission and prospects for future groundbreaking observations of supernova remnants will be discussed.

Petre, Robert

2006-01-01

89

High-resolution X-ray imaging of the supernova remnant MSH 15-52  

NASA Astrophysics Data System (ADS)

We present high-resolution ROSAT observations of PSR 1509-58 and the supernova remnant MSH 15-52. The pulsar itself is resolved from the surrounding synchrotron nebula as a 75 per cent pulsed point source. The synchrotron emission forms a broad, elongated cross centred on the pulsar, and an extrapolation of the north-western arm of the cross to the supernova remnant rim coincides with the RCW 89 H? nebula. More than half of the X-ray flux in RCW 89 is resolved into a partial ring of tight knots that closely follow the radio morphology of the region. We suggest that all of the X-ray emission in the field of PSR 1509-58 can be explained if the system is similar to the `torus' and `jets' of the Crab pulsar synchrotron nebula, but viewed at more than ~70 deg to the pulsar spin axis. For current theories, this inclination favours pulsar emission from the outer, rather than the inner, magnetosphere. The luminosity of RCW 89 is driven in our model by the pulsar wind, which suggests that the NW-SE axis of the synchrotron nebula marks a collimated outflow along the pulsar spin axis, making PSR 1509-58 the third example of an isolated pulsar with a polar outflow.

Brazier, K. T. S.; Becker, W.

1997-01-01

90

Separated before birth: pulsars B2020+28 and B2021+51 as the remnants of runaway stars  

E-print Network

Astrometric data on the pulsars B2020+28 and B2021+51 suggest that they originated within several parsecs of each other in the direction of the Cyg OB2 association. It was proposed that the pulsars share their origin in a common massive binary and were separated at the birth of the second pulsar following the asymmetric supernova explosion. We consider a different scenario for the origin of the pulsar pair based on a possibility that the pulsars were separated before their birth and that they are the remnants of runaway stars ejected (with velocities similar to those of the pulsars) from the core of Cyg OB2 due to strong three- or four-body dynamical encounters. Our scenario does not require any asymmetry in supernova explosions.

V. V. Gvaramadze

2007-05-29

91

High Resolution Spectroscopy of Supernova Remnants  

Microsoft Academic Search

With the advent of XMM-Newton and Chandra, high resolution spectroscopy has become a new tool for investigating supernova remnants. In the near future it will become even more important as micro calorimeters are entering the field, for example with ASTRO-E2, Constellation-X and Xeus. High resolution spectroscopy is an important diagnostic tool for measuring plasma properties, such as plasma temperatures, non-equilibrium

J. Vink

2004-01-01

92

Supernova remnants in the Large Magellanic Cloud.  

NASA Astrophysics Data System (ADS)

This paper reviews the mechanisms and types of radiation - radio, X-ray, optical, near infrared and infrared - produced by supernova remnants (SNR). New radio data on a selected group of SNRs in the LMC and at various wavelengths are now available from the Australia Telescope. These will be discussed with respect to three different objects, N132D, N49 and N157B which have different characteristics - a young, an adolescent and a Crab-type SNR.

Dickel, J. R.

1994-06-01

93

G65.2+5.7: A Thermal Composite Supernova Remnant with a Cool Shell  

NASA Technical Reports Server (NTRS)

This paper presents archival ROSAT PSPC observations of the G65.2+5.7 supernova remnant (also known as G65.3+5.7). Little material obscures this remnant and so it was well observed, even at the softest end of ROSATs bandpass (approx. 0.11 to 0.28 keV). These soft X-ray images reveal the remnant s centrally-filled morphology which, in combination with existing radio frequency observations, places G65.2+5.7 in the thermal composite (mixed morphology) class of supernova remnants. Not only might G65.2+5.7 be the oldest known thermal composite supernova remnant, but owing to its optically revealed cool, dense shell, this remnant supports the proposal that thermal composite supernova remnants lack X-ray bright shells because they have evolved beyond the adiabatic phase. These observations also reveal a slightly extended point source centered on RA = l9(sup h) 36(sup m) 46(sup s). dec = 30 deg.40 min.07 sec.and extending 6.5 arc min in radius in the band 67 map. The source of this emission has yet to be discovered, as there is no known pulsar at this location.

Shelton, R. L.; Kuntz, K. D.; Petre, R.

2004-01-01

94

Supernova Remnant SNR 0509 Lithograph and In Search of... Supernova Remnants Classroom Activity  

NSDL National Science Digital Library

This Hubble Space Telescope image shows what appears to be a delicate bubble of gas floating in space. In actuality, the bubble is the visible remnant of a powerful supernova explosion called SNR 0509. The bubble was formed from gas being swept up by the expanding shock wave. The accompanying activity is a curriculum support tool designed for use as an introductory inquiry activity. In the activity, students use the images and text on this lithograph to generate questions about supernova explosions and remnants. They will conduct research to answer their questions, and create a presentation to demonstrate their understanding of the material, providing supporting evidence from their research.

2011-01-01

95

Four extended gamma-ray supernova remnants newly identified by Fermi-LAT Pass 8 data  

NASA Astrophysics Data System (ADS)

Identifying gamma-ray emission from supernova remnants is crucial to determine the origin of Galactic cosmic rays. Despite the excellent sensitivity and spatial resolution of the Fermi Gamma-ray Space Telescope, it has proven difficult to clearly identify these sources as they are buried in the bright diffuse Galactic background and may be confused with other gamma-ray sources, such as pulsars. Here we report the detection of extended emission from four supernova remnants - CTB 109, PKS 1209-51/52, CTB 37A, RCW 86 - using 5 years of observations with Fermi and the new Pass 8 event reconstruction developed by the LAT collaboration. The improvements with Pass 8 promise to rapidly grow the population of gamma-ray supernova remnants identified through their spatial extension.

Hewitt, John W.; Fermi-LAT Collaboration

2015-01-01

96

Kepler's Supernova Remnant: The view at 400 Years  

E-print Network

October 2004 marks the 400th anniversary of the sighting of SN 1604, now marked by the presence of an expanding nebulosity known as Kepler's supernova remnant. Of the small number of remnants of historical supernovae, Kepler's remnant remains the most enigmatic. The supernova type, and hence the type of star that exploded, is still a matter of debate, and even the distance to the remnant is uncertain by more than a factor of two. As new and improved multiwavength observations become available, and as the time baseline of observations gets longer, Kepler's supernova remnant is slowly revealing its secrets. I review recent and current observations of Kepler's supernova remnant and what they indicate about this intriguing object.

W. P. Blair

2004-10-04

97

Distance Determination to the Crab-Like Pulsar Wind Nebula G54.1+0.3 and the Search for its Supernova Remnant Shell  

Microsoft Academic Search

We discovered a large-scale shell G53.9+0.2 around the Crab-like pulsar wind nebula (PWN) G54.1+0.3 with 1420 MHz continuum Very Large Array observations. This is confirmed by a new infrared (IR) image at 8 mum from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire project, which reveals an intriguing IR shell just surrounding the large radio shell. We analyze the 21 cm

Denis A. Leahy; Wenwu Tian; Q. D. Wang

2008-01-01

98

Pulsar recoil by large-scale anisotropies in supernova explosions.  

PubMed

Assuming that the neutrino luminosity from the neutron star core is sufficiently high to drive supernova explosions by the neutrino-heating mechanism, we show that low-mode (l=1,2) convection can develop from random seed perturbations behind the shock. A slow onset of the explosion is crucial, requiring the core luminosity to vary slowly with time, in contrast to the burstlike exponential decay assumed in previous work. Gravitational and hydrodynamic forces by the globally asymmetric supernova ejecta were found to accelerate the remnant neutron star on a time scale of more than a second to velocities above 500 km s(-1), in agreement with observed pulsar proper motions. PMID:14753979

Scheck, L; Plewa, T; Janka, H-Th; Kifonidis, K; Mller, E

2004-01-01

99

VHE Gamma-ray Supernova Remnants  

SciTech Connect

Increasing observational evidence gathered especially in X-rays and {gamma}-rays during the course of the last few years support the notion that Supernova remnants (SNRs) are Galactic particle accelerators up to energies close to the ''knee'' in the energy spectrum of Cosmic rays. This review summarizes the current status of {gamma}-ray observations of SNRs. Shell-type as well as plerionic type SNRs are addressed and prospect for observations of these two source classes with the upcoming GLAST satellite in the energy regime above 100 MeV are given.

Funk, Stefan; /KIPAC, Menlo Park

2007-01-22

100

5 GHz observations of galactic supernova remnants  

NASA Technical Reports Server (NTRS)

Brightness and polarization distributions over several galactic supernova remnants have been observed at a wavelength of 6 cm. These observations have confirmed the nonthermal nature of most of the observed sources. It is suggested, however, that the objects G33.1-0.1 (KES 78), G35.6-0.0, G37.6-0.1, G37.7+0.1, and G37.9-0.4 are thermal. The results of these observations are presented in the form of total intensity contour maps with superimposed polarization vectors.

Angerhofer, P. E.; Kundu, M. R.; Becker, R. H.

1977-01-01

101

The molecular emission from old supernova remnants  

E-print Network

Supernovae constitute a critical source of energy input to the interstellar medium (ISM). In this short review, we focus on their latest phase of evolution, the supernova remnants (SNRs). We present observations of three old SNRs that have reached the phase where they interact with the ambient ISM: W28, IC443, and 3C391. We show that such objects make up clean laboratories to constrain the physical and chemical processes at work in molecular shock environments. Our studies subsequently allow us to quantify the impact of SNRs on their environment in terms of mass, momentum, and energy dissipation. In turn, their contribution to the energy balance of galaxies can be assessed. Their potential to trigger a further generation of star formation can also be investigated. Finally, our studies provide strong support for the interpretation of gamma-ray emission in SNRs, a crucial step to answer questions related to cosmic rays population and acceleration.

Gusdorf, Antoine; Anderl, Sibylle; Hezareh, Talayeh

2014-01-01

102

Multi-Wavelength Observations of Supernova Remnants  

NASA Technical Reports Server (NTRS)

Supernova remnants (SNRs) provide a laboratory for studying various astrophysical processes, including particle acceleration, thermal and non thermal emission processes across the spectrum, distribution of heavy elements, the physics of strong shock waves, and the progenitor systems and environments of supernovae. Long studied in radio and X-rays, the past decade has seen a dramatic increase in the detection and subsequent study of SNRs in the infrared and gamma-ray regimes. Understanding the evolution of SNRs and their interaction with the interstellar medium requires a multi-wavelength approach. I will review the various physical processes observed in SNRs and how these processes are intertwined. In particular, I will focus on X-ray and infrared observations, which probe two very different but intrinsically connected phases of the ISM: gas and dust. I will discuss results from multi-wavelength studies of several SNRs at various stages of evolution, including Kepler, RCW 86, and the Cygnus Loop.

Williams, B.

2012-01-01

103

Vivid View of Tycho's Supernova Remnant  

NASA Technical Reports Server (NTRS)

This composite image of the Tycho supernova remnant combines infrared and X-ray observations obtained with NASA's Spitzer and Chandra space observatories, respectively, and the Calar Alto observatory, Spain. It shows the scene more than four centuries after the brilliant star explosion witnessed by Tycho Brahe and other astronomers of that era.

The explosion has left a blazing hot cloud of expanding debris (green and yellow). The location of the blast's outer shock wave can be seen as a blue sphere of ultra-energetic electrons. Newly synthesized dust in the ejected material and heated pre-existing dust from the area around the supernova radiate at infrared wavelengths of 24 microns (red). Foreground and background stars in the image are white.

2008-01-01

104

Reverse-Shock in Tycho's Supernova Remnant  

E-print Network

Thermal X-ray emission from young supernova remnants (SNRs) is usually dominated by the emission lines of the supernova (SN) ejecta, which are widely believed being crossed and thus heated by the inwards propagating reverse shock (RS). Previous works using imaging X-ray data have shown that the ejecta are heated by the RS by locating the peak emission region of the most recently ionized matter, which is found well separated towards the inside from the outermost boundary. Here we report the discovery of a systematic increase of the Sulfur (S) to Silicon (Si) K$\\alpha$ line flux ratio with radius in Tycho's SNR. This allows us, for the first time, to present continuous radial profiles of the ionization age and, furthermore, the elapsed ionization time since the onset of the ionization, which tells the propagation history of the ionization front into the SNR ejecta.

Lu, F J; Zheng, S J; Zhang, S N; Long, X; Aschenbach, B

2015-01-01

105

On neutron star/supernova remnant associations  

E-print Network

It is pointed out that a cavity supernova (SN) explosion of a moving massive star could result in a significant offset of the neutron star (NS) birth-place from the geometrical centre of the supernova remnant (SNR). Therefore: a) the high implied transverse velocities of a number of NSs (e.g. PSR B1610-50, PSR B1757-24, SGR0525-66) could be reduced; b) the proper motion vector of a NS should not necessarily point away from the geometrical centre of the associated SNR; c) the circle of possible NS/SNR associations could be enlarged. An observational test is discussed, which could allow to find the true birth-places of NSs associated with middle-aged SNRs, and thereby to get more reliable estimates of their transverse velocities.

V. V. Gvaramadze

2001-04-01

106

Radioactivity and electron acceleration in supernova remnants  

SciTech Connect

We argue that the decays of radioactive nuclei related to {sup 44}Ti and {sup 56}Ni ejected during supernova explosions can provide a vast pool of mildly relativistic positrons and electrons which are further accelerated to ultrarelativistic energies by reverse and forward shocks. This interesting link between two independent processes - the radioactivity and the particle acceleration - can be a clue for solution of the well known theoretical problem of electron injection in supernova remnants. In the case of the brightest radio source Cas A, we demonstrate that the radioactivity can supply adequate number of energetic electrons and positrons for interpretation of observational data provided that they are stochastically preaccelerated in the upstream regions of the forward and reverse shocks.

Zirakashvili, V. N. [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation, 142190 Troitsk, Moscow Region (Russian Federation); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Aharonian, F. A. [Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2011-10-15

107

Chandra Observations of Supernova Remnants and Neutron Stars: An Overview  

NASA Technical Reports Server (NTRS)

We present a brief overview of Chandra observations of supernova remnants and neutron stars, with emphasis on neutron stars in supernova remnants. The Chandra images demonstrate the importance of angular resolution in separating the neutron star emission from the surrounding nebulosity.

Weisskopf, Martin C.

2002-01-01

108

HESS upper limits for Kepler's supernova remnant  

NASA Astrophysics Data System (ADS)

Aims: Observations of Kepler's supernova remnant (G4.5+6.8) with the HESS telescope array in 2004 and 2005 with a total live time of 13 h are presented. Methods: Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays. Results: No evidence for a very high energy (VHE: >100 GeV) gamma-ray signal from the direction of the remnant is found. An upper limit (99% confidence level) on the energy flux in the range 230 GeV{-}12.8 TeV of 8.6 10-13 erg cm-2 s-1 is obtained. Conclusions: In the context of an existing theoretical model for the remnant, the lack of a detectable gamma-ray flux implies a distance of at least 6.4 kpc. A corresponding upper limit for the density of the ambient matter of 0.7 cm-3 is derived. With this distance limit, and assuming a spectral index ? = 2, the total energy in accelerated protons is limited to Ep < 8.6 1049 erg. In the synchrotron/inverse Compton framework, extrapolating the power law measured by RXTE between 10 and 20 keV down in energy, the predicted gamma-ray flux from inverse Compton scattering is below the measured upper limit for magnetic field values greater than 52 ? G.

Aharonian, F.; Akhperjanian, A. G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Behera, B.; Beilicke, M.; Benbow, W.; Berge, D.; Bernlhr, K.; Boisson, C.; Bolz, O.; Borrel, V.; Braun, I.; Brion, E.; Brucker, J.; Bhler, R.; Bulik, T.; Bsching, I.; Boutelier, T.; Carrigan, S.; Chadwick, P. M.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Cornils, R.; Costamante, L.; Dalton, M.; Degrange, B.; Dickinson, H. J.; Djannati-Ata, A.; Domainko, W.; O'C. Drury, L.; Dubois, F.; Dubus, G.; Dyks, J.; Egberts, K.; Emmanoulopoulos, D.; Espigat, P.; Farnier, C.; Feinstein, F.; Fiasson, A.; Frster, A.; Fontaine, G.; Fling, M.; Gallant, Y. A.; Giebels, B.; Glicenstein, J. F.; Glck, B.; Goret, P.; Hadjichristidis, C.; Hauser, D.; Hauser, M.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jung, I.; Katarzy?ski, K.; Kendziorra, E.; Kerschhaggl, M.; Khlifi, B.; Keogh, D.; Komin, Nu.; Kosack, K.; Lamanna, G.; Latham, I. J.; Lemoine-Goumard, M.; Lenain, J.-P.; Lohse, T.; Martin, J. M.; Martineau-Huynh, O.; Marcowith, A.; Masterson, C.; Maurin, D.; McComb, T. J. L.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nolan, S. J.; Ohm, S.; Olive, J.-P.; de Oa Wilhelmi, E.; Orford, K. J.; Osborne, J. L.; Ostrowski, M.; Panter, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Phlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Renaud, M.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Ruppel, J.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schck, F. M.; Schrder, R.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sol, H.; Spangler, D.; Stawarz, ?.; Steenkamp, R.; Stegmann, C.; Superina, G.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Vincent, P.; Vivier, M.; Vlk, H. J.; Volpe, F.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.

2008-09-01

109

Three Great Eyes on Kepler's Supernova Remnant  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Composite

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Chandra X-Ray Data (blue) Chandra X-Ray Data (green)Hubble Telescope (visible-light)Spitzer Telescope (infrared)

NASA's three Great Observatories -- the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory -- joined forces to probe the expanding remains of a supernova, called Kepler's supernova remnant, first seen 400 years ago by sky watchers, including astronomer Johannes Kepler.

The combined image unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 4 million miles per hour (2,000 kilometers per second). Observations from each telescope highlight distinct features of the supernova remnant, a fast-moving shell of iron-rich material from the exploded star, surrounded by an expanding shock wave that is sweeping up interstellar gas and dust.

Each color in this image represents a different region of the electromagnetic spectrum, from X-rays to infrared light. These diverse colors are shown in the panel of photographs below the composite image. The X-ray and infrared data cannot be seen with the human eye. By color-coding those data and combining them with Hubble's visible-light view, astronomers are presenting a more complete picture of the supernova remnant.

Visible-light images from the Hubble telescope (colored yellow) reveal where the supernova shock wave is slamming into the densest regions of surrounding gas. The bright glowing knots are dense clumps from instabilities that form behind the shock wave. The Hubble data also show thin filaments of gas that look like rippled sheets seen edge-on. These filaments reveal where the shock wave is encountering lower-density, more uniform interstellar material.

The Spitzer telescope shows microscopic dust particles (colored red) that have been heated by the supernova shock wave. The dust re-radiates the shock wave's energy as infrared light. The Spitzer data are brightest in the regions surrounding those seen in detail by the Hubble telescope.

The Chandra X-ray data show regions of very hot gas, and extremely high-energy particles. The hottest gas (higher-energy X-rays, colored blue) is located primarily in the regions directly behind the shock front. These regions also show up in the Hubble observations, and also align with the faint rim of glowing material seen in the Spitzer data. The X-rays from the region on the lower left (colored blue) may be dominated by extremely high-energy electrons that were produced by the shock wave and are radiating at radio through X-ray wavelengths as they spiral in the intensified magnetic field behind the shock front. Cooler X-ray gas (lower-energy X-rays, colored green) resides in a thick interior shell and marks the location of heated material expelled from the exploded star.

Kepler's supernova, the last such object seen to explode in our Milky Way galaxy, resides about 13,000 light-years away in the constellation Ophiuchus.

The Chandra observations were taken in June 2000, the Hubble in August 2003; and the Spitzer in August 2004.

2004-01-01

110

PAH and Dust Processing in Supernova Remnants  

NASA Astrophysics Data System (ADS)

I present observations of shock-processed PAHs and dust in supernova remnants (SNRs). Supernova shocks are one of the primary sites destroying, fragmenting and altering interstellar PAHs and dust. Studies of PAHs through supernova shocks had been limited because of confusion with PAHs in background emission. Spitzer observations with high sensitivity and resolution allow us to separate PAHs associated with the SNRs and unrelated, Galactic PAHs. In the young SNR N132D, PAH features are detected with a higher PAH ratio of 15-20/7.7 ?m than those of other astronomical objects, and we suggest large PAHs have survived behind the shock. We present the spectra of additional 14 SNRs observed with Spitzer IRS and MIPS SED covering the range of 5-90 ?m. Bright PAH features from 6.2 to 15-20 ?m are detected from many of SNRs which emit molecular hydrogen lines, indicating that both large and small PAHs survive in low velocity shocks. We observe a strong correlation between PAH detection and carbonaceous small grains, while a few SNRs with dominant silicate dust lack PAH features. We characterize PAHs depending on the shock velocity, preshock density and temperature of hot gas, and discuss PAH and dust processing in shocks and implication of PAH and dust cycles in ISM.

Rho, J.; Andersen, M.; Tappe, A.; Reach, W. T.; Bernard, J. P.; Hewitt, J.

2011-03-01

111

Searches for continuous gravitational waves from nine young supernova remnants  

E-print Network

We describe directed searches for continuous gravitational waves in data from the sixth LIGO science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of ten. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering F-statistic. We found no credible gravitational-wave signals. We set 95% confidence upper limits as strong (low) as $4\\times10^{-25}$ on intrinsic strain, $2\\times10^{-7}$ on fiducial ellipticity, and $4\\times10^{-5}$ on r-mode amplitude. These beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star ellipticities and r-mode amplitudes.

J. Aasi; B. P. Abbott; R. Abbott; T. Abbott; M. R. Abernathy; F. Acernese; K. Ackley; C. Adams; T. Adams; T. Adams; P. Addesso; R. X. Adhikari; V. Adya; C. Affeldt; M. Agathos; K. Agatsuma; N. Aggarwal; O. D. Aguiar; A. Ain; P. Ajith; A. Alemic; B. Allen; A. Allocca; D. Amariutei; S. B. Anderson; W. G. Anderson; K. Arai; M. C. Araya; C. Arceneaux; J. S. Areeda; S. Ast; S. M. Aston; P. Astone; P. Aufmuth; C. Aulbert; B. E. Aylott; S. Babak; P. T. Baker; F. Baldaccini; G. Ballardin; S. W. Ballmer; J. C. Barayoga; M. Barbet; S. Barclay; B. C. Barish; D. Barker; F. Barone; B. Barr; L. Barsotti; M. Barsuglia; J. Bartlett; M. A. Barton; I. Bartos; R. Bassiri; A. Basti; J. C. Batch; Th. S. Bauer; C. Baune; V. Bavigadda; B. Behnke; M. Bejger; C. Belczynski; A. S. Bell; C. Bell; M. Benacquista; J. Bergman; G. Bergmann; C. P. L. Berry; D. Bersanetti; A. Bertolini; J. Betzwieser; S. Bhagwat; R. Bhandare; I. A. Bilenko; G. Billingsley; J. Birch; S. Biscans; M. Bitossi; C. Biwer; M. A. Bizouard; J. K. Blackburn; L. Blackburn; C. D. Blair; D. Blair; S. Bloemen; O. Bock; T. P. Bodiya; M. Boer; G. Bogaert; P. Bojtos; C. Bond; F. Bondu; L. Bonelli; R. Bonnand; R. Bork; M. Born; V. Boschi; Sukanta Bose; C. Bradaschia; P. R. Brady; V. B. Braginsky; M. Branchesi; J. E. Brau; T. Briant; D. O. Bridges; A. Brillet; M. Brinkmann; V. Brisson; A. F. Brooks; D. A. Brown; D. D. Brown; N. M. Brown; S. Buchman; A. Buikema; T. Bulik; H. J. Bulten; A. Buonanno; D. Buskulic; C. Buy; L. Cadonati; G. Cagnoli; J. Caldern Bustillo; E. Calloni; J. B. Camp; K. C. Cannon; J. Cao; C. D. Capano; F. Carbognani; S. Caride; S. Caudill; M. Cavagli; F. Cavalier; R. Cavalieri; G. Cella; C. Cepeda; E. Cesarini; R. Chakraborty; T. Chalermsongsak; S. J. Chamberlin; S. Chao; P. Charlton; E. Chassande-Mottin; Y. Chen; A. Chincarini; A. Chiummo; H. S. Cho; M. Cho; J. H. Chow; N. Christensen; Q. Chu; S. Chua; S. Chung; G. Ciani; F. Clara; J. A. Clark; F. Cleva; E. Coccia; P. -F. Cohadon; A. Colla; C. Collette; M. Colombini; L. Cominsky; M. Constancio, Jr.; A. Conte; D. Cook; T. R. Corbitt; N. Cornish; A. Corsi; C. A. Costa; M. W. Coughlin; J. -P. Coulon; S. Countryman; P. Couvares; D. M. Coward; M. J. Cowart; D. C. Coyne; R. Coyne; K. Craig; J. D. E. Creighton; T. D. Creighton; J. Cripe; S. G. Crowder; A. Cumming; L. Cunningham; E. Cuoco; C. Cutler; K. Dahl; T. Dal Canton; M. Damjanic; S. L. Danilishin; S. D'Antonio; K. Danzmann; L. Dartez; V. Dattilo; I. Dave; H. Daveloza; M. Davier; G. S. Davies; E. J. Daw; R. Day; D. DeBra; G. Debreczeni; J. Degallaix; M. De Laurentis; S. Delglise; W. Del Pozzo; T. Denker; T. Dent; H. Dereli; V. Dergachev; R. De Rosa; R. T. DeRosa; R. DeSalvo; S. Dhurandhar; M. Daz; L. Di Fiore; A. Di Lieto; I. Di Palma; A. Di Virgilio; G. Dojcinoski; V. Dolique; E. Dominguez; F. Donovan; K. L. Dooley; S. Doravari; R. Douglas; T. P. Downes; M. Drago; J. C. Driggers; Z. Du; M. Ducrot; S. Dwyer; T. Eberle; T. Edo; M. Edwards; M. Edwards; A. Effler; H. -B. Eggenstein; P. Ehrens; J. Eichholz; S. S. Eikenberry; R. Essick; T. Etzel; M. Evans; T. Evans; M. Factourovich; V. Fafone; S. Fairhurst; X. Fan; Q. Fang; S. Farinon; B. Farr; W. M. Farr; M. Favata; M. Fays; H. Fehrmann; M. M. Fejer; D. Feldbaum; I. Ferrante; E. C. Ferreira; F. Ferrini; F. Fidecaro; I. Fiori; R. P. Fisher; R. Flaminio; J. -D. Fournier; S. Franco; S. Frasca; F. Frasconi; Z. Frei; A. Freise; R. Frey; T. T. Fricke; P. Fritschel; V. V. Frolov; S. Fuentes-Tapia; P. Fulda; M. Fyffe; J. R. Gair; L. Gammaitoni; S. Gaonkar; F. Garufi; A. Gatto; N. Gehrels; G. Gemme; B. Gendre; E. Genin; A. Gennai; L. . Gergely; S. Ghosh; J. A. Giaime; K. D. Giardina; A. Giazotto; J. Gleason; E. Goetz; R. Goetz; L. Gondan; G. Gonzlez; N. Gordon; M. L. Gorodetsky; S. Gossan; S. Goler; R. Gouaty; C. Grf; P. B. Graff; M. Granata; A. Grant; S. Gras; C. Gray; R. J. S. Greenhalgh; A. M. Gretarsson; P. Groot; H. Grote; S. Grunewald; G. M. Guidi; C. J. Guido; X. Guo; K. Gushwa; E. K. Gustafson; R. Gustafson; J. Hacker; E. D. Hall; G. Hammond; M. Hanke; J. Hanks; C. Hanna; M. D. Hannam; J. Hanson; T. Hardwick; J. Harms; G. M. Harry; I. W. Harry; M. Hart; M. T. Hartman; C. -J. Haster; K. Haughian; S. Hee; A. Heidmann; M. Heintze; G. Heinzel; H. Heitmann; P. Hello; G. Hemming; M. Hendry; I. S. Heng; A. W. Heptonstall; M. Heurs; M. Hewitson; S. Hild; D. Hoak; K. A. Hodge; D. Hofman; S. E. Hollitt; K. Holt; P. Hopkins; D. J. Hosken; J. Hough; E. Houston; E. J. Howell; Y. M. Hu; E. Huerta; B. Hughey; S. Husa; S. H. Huttner; M. Huynh; T. Huynh-Dinh; A. Idrisy; N. Indik; D. R. Ingram; R. Inta; G. Islas; J. C. Isler; T. Isogai; B. R. Iyer; K. Izumi; M. Jacobson; H. Jang; P. Jaranowski; S. Jawahar; Y. Ji; F. Jimnez-Forteza; W. W. Johnson; D. I. Jones; R. Jones; R. J. G. Jonker; L. Ju; Haris K; V. Kalogera; S. Kandhasamy; G. Kang; J. B. Kanner; M. Kasprzack; E. Katsavounidis; W. Katzman

2014-12-18

112

A Study of Supernova Remnants with Center-Filled X-Ray Morphology  

NASA Technical Reports Server (NTRS)

CTA 1 is a center-filled supernova remnant (SNR) whose morphology and spectrum indicate the presence of a central pulsar, a synchrotron nebula, and a thermal component associated with the expansion of the blast wave into the interstellar medium. The centrally bright emission surrounds the position of a faint point source of x-rays observed with the ROSAT PSPC. Here we report on ASCA observations that confirm the nonthermal nature of the diffuse emission from the central regions of the remnant. We also present evidence for weak thermal emission that appears to increase in strength toward the outer boundary of the SNR. Thus, CTA 1 appears to be an x-ray composite remnant. Both the aftermath of the explosive supernova event and the energetic compact core are observable.

Slane, Patrick O.

1997-01-01

113

An optical and near infrared search for a pulsar in Supernova 1987A  

SciTech Connect

We describe a search for an optical pulsar in the remnant of Supernova 1987A. We have performed over one hundred separate observations of the supernova, covering wavelengths from 3500 angstroms to 1.8 microns, with sensitivity to pulsations as faint as magnitude 22.7. As of September 26, 1990, we have not seen evidence for pulsations due to a pulsar in the supernova. We discuss the implications of this result on predictions of pulsar optical luminosity. We have constructed for the search two photodiode detectors and a data system. We describe their design, calibration and performance. These detectors have allowed us to increase our sensitivity as much as a factor of 5 over standard photomultiplier tubes, and extend this search to near infrared wavelengths. 59 refs., 10 figs., 1 tab.

Sasseen, T.P.

1990-12-01

114

ASCA observations of the Large Magellanic Cloud supernova remnant sample: Typing supernovae from their remnants  

NASA Technical Reports Server (NTRS)

We present our first results from a study of the supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) using data from ASCA. The three remnants we have analyzed to date, 0509-67.5, 0519-69.0, and N103B, are among the smallest, and presumably also the youngest, in the Cloud. The X-ray spectra of these SNRs show strong K alpha emission lines of silicon, sulfur, argon, and calcium with no evidence for corresponding lines of oxygen, neon, or magnesium. The dominant feature in the spectra is a broad blend of emission lines around 1 keV which we attribute to L-shell emission lines of iron. Model calculations (Nomoto, Thielemann, & Yokoi 1984) show that the major products of nucleosynthesis in Type Ia supernovae (SNs) are the elements from silicon to iron, as observed here. The calculated nucleosynthetic yields from Type Ib and II SNs are shown to be qualitatively inconsistent with the data. We conclude that the SNs which produced these remnants were of Type Ia. This finding also confirms earlier suggestions that the class of Balmer-dominated remnants arise from Type Ia SN explosions. Based on these early results from the LMC SNR sample, we find that roughly one-half of the SNRs produced in the LMC within the last approximately 1500 yr came from Type Ia SNs.

Hughes, John P.; Hayashi, Ichizo; Helfand, David; Hwang, Una; Itoh, Masayuki; Kirshner, Robert; Koyama, Katsuji; Markert, Thomas; Tsunemi, Hiroshi; Woo, Jonathan

1995-01-01

115

Particle Acceleration by Shocks in Supernova Remnants  

NASA Astrophysics Data System (ADS)

Particle acceleration occurs on a range of scales from AU in the heliosphere to Mpc in clusters of galaxies and to energies ranging from MeV to exaelectronvolt (EeV). A number of acceleration processes have been proposed, but diffusive shock acceleration (DSA) is widely invoked as the predominant mechanism. DSA operates on all these scales and probably to the highest energies. DSA is simple, robust and predicts a universal spectrum. However, there are still many unknowns regarding particle acceleration. This paper focuses on the particular question of whether supernova remnants (SNR) can produce the Galactic cosmic ray (CR) spectrum up to the knee at a few petaelectronvolt (PeV). The answer depends in large part on the detailed physics of diffusive shock acceleration.

Bell, Anthony Raymond

2014-10-01

116

Supernova remnants and the physics of strong shock waves  

NASA Technical Reports Server (NTRS)

This paper reports on a Workshop on Supernova Remnants and the Physics of Strong Shock Waves hosted by North Carolina State University at Raleigh, North Carolina, September 16-18, 1993. The workshop brought together observers, shock theorists, cosmic-ray specialists, and simulators to address the role supernova remnants can play in furthering our understanding of the complex plasma physics associated with collisionless shocks and particle acceleration. Over fifty scientists presented papers on various aspects of supernova remnants. In lieu of a proceedings volume, we present here a synopsis of the workshop, in the form of brief summaries of each workshop session.

Ellison, Donald C.; Reynolds, Stephen P.; Borkowski, Kazimierz; Chevalier, Roger; Cox, Donald P.; Dickel, John R.; Pisarski, Ryszard; Raymond, John; Spangler, Stephen R.; Volk, Heinrich J.

1994-01-01

117

Supernova remnants and spiral structure of the Galaxy.  

NASA Astrophysics Data System (ADS)

The supernova remnants in our Galaxy are studied on the basis of the evolution of molecular clouds. From the CO observations, a lot of reliable data on molecular clouds have been derived. If the author's theoretical results can match the observed ones, his conclusions about supernova remnants based on such observations will be convincing. It is shown that the possible supernova remnants in the inner Galaxy are (75512)?5. The spiral structure will make more SNRs appear in the arm region rather than enhance the productivity of SNRs on the global scale.

Song, Guoxuan

1999-05-01

118

The evolution of supernova remnants in different galactic environments, and its effects on supernova statistics  

NASA Technical Reports Server (NTRS)

Examination of the interaction between supernova (SN) ejecta and the various environments in which the explosive event might occur shows that only a small fraction of the many SNs produce observable supernova remnants (SNRs). This fraction, which is found to depend weakly upon the lower mass limit of the SN progenitors, and more strongly on the specfic characteristics of the associated interstellar medium, decreases from approximately 15 percent near the galctic center to 10 percent at Rgal approximately 10 kpc and drops nearly to zero for Rgal 15 kpc. Generally, whether a SNR is detectable is determined by the density of the ambient interstellar medium in which it is embeeede. The presence of large, low density cavities arpund stellar associations due to the combined effects of stellar winds and supernova shells strongly suggests that a large portion of the detectable SNRs have runway stars as their progenitors. These results explain the differences between the substantially larger SN rates in the galaxy derived both from pulsar statistics and from observations of SN events in external galaxies, when compared to the substantially smaller SN rates derived form galactic SNR statistics.

Kafatos, M.; Sofia, S.; Bruhweiler, F.; Gull, T. R.

1980-01-01

119

SPITZER SPECTRAL MAPPING OF SUPERNOVA REMNANT CASSIOPEIA A  

E-print Network

We present the global distribution of fine-structure infrared line emission in the Cassiopeia A supernova remnant using data from the Spitzer Space Telescope's infrared spectrograph. We identify emission from ejecta materials ...

Smith, J. D. T.

120

FERMI -LAT OBSERVATIONS OF SUPERNOVA REMNANTS KESTEVEN 79  

E-print Network

In this paper, we report on the detection of ?-ray emission coincident with the Galactic supernova remnant (SNR) Kesteven 79 (Kes 79). We analyzed approximately 52 months of data obtained with the Large Area Telescope on ...

Auchettl, Katie

121

Locating the Periodic Transient GRO J1849-03; Gamma-Ray Luminous Supernovae Remnants  

NASA Technical Reports Server (NTRS)

We obtained one 50 ks observation of the Monoceros supernova remnant under this proposal. This supernova remnant was selected because it overlaps the error box of a gamma-ray source. Much to our surprise, we discovered a hard x-ray point source instead of the diffuse hard x-ray emission we expected from the supernova remnant. A paper on the discovery of the hard x-ray source and on follow-up optical observations identifying a likely Bestar companion was published in the Astrophysical Journal. Subsequently, a reanalysis of the same data yielded the detection of pulsations from the x-ray source. These results were also published in the Astrophysical Journal. Subsequent x-ray observations, which we performed under later proposals, have shown that the x-ray pulsar has a characteristic spin-down age of less than 1400 years in a binary system. The system is likely the first discovered very young, highly-energetic, rotation-powered pulsar in a binary system and offers an exciting opportunity to study the infancy and early evolution of neutron-star binaries.

Kaaret, P.; White, Nicholas (Technical Monitor)

2000-01-01

122

Shock Destruction of Dust in Supernova Remnants  

NASA Astrophysics Data System (ADS)

In this AR-Theory program, we propose to carry out a series of investigations of grain injection, transport, and destruction using hydrodynamical models of reverse-shocked SN ejecta. In a young supernova remnant {SNR} such as Cas A or SN 1987A the outer blast wave strikes surrounding circumstellar matter, and reverse shocks propagate inward toward the interior debris, which may contain large amounts of newly formed dust. Our major theoretical goals are to determine how much dust is destroyed in shocked SNR ejecta, as they are decelerated by the reverse shocks, and to study how these ejecta are lighted up in optical, X-ray, andIR line emission. Numerical codes will be used to study grain destruction in metal-enriched ejecta and to interpret the morphologies, proper motions, and emissivities of these fast-moving ejecta, observed by Hubble in many young SNRs. We intend to undertake the following tasks: {1} Compile the latest gas-grain data {sputtering yields vs projectile energy for H, He, and heavy ions}; {2} Incorporate gas-grain and grain-grain interactions with radiative cooling rates {X-ray, optical, IR line emission} of sputtered atoms and ions; {3} Compute adaptive-mesh hydrodynamical models of ejecta-shock interactions; {4} Use these ejecta models to compute grain destruction, grain heating, plasma cooling, and spectral diagnostics in metal-enriched environments; {5} Apply our results to specific SNRs {Cas A, SN 1987A, G292, etc} to interpret ejecta morphologies, proper motions, and emissivities; {6} assess the net efficiency of supernova dust injection.

Shull, J.

2009-07-01

123

Supernova Remnant OH Masers: Signposts of Cosmic Collision  

Microsoft Academic Search

A supernova explosion, the final death throe of a massive star, creates an expanding bubble of hot gas that overruns up the surrounding medium. When a supernova remnant encounters a dense interstellar cloud, the compression may trigger gravita- tional collapse and the formation of a new generation of stars. This event can be detected through intense stimulated emission in the

Supernova Remnant Masers

124

Supernova Remnant OH Masers: Signposts of Cosmic Collision  

Microsoft Academic Search

A supernova explosion, the final death throe of a massive star, creates an expanding bubble of hot gas that overruns up the surrounding medium. When a supernova remnant encounters a dense interstellar cloud, the compression may trigger gravitational collapse and the formation of a new generation of stars. This event can be detected through intense stimulated emission in the 1720-megahertz

Mark Wardle; Farhad Yusef-Zadeh

2002-01-01

125

XMM-NEWTON OBSERVATIONS OF TWO CANDIDATE SUPERNOVA REMNANTS  

SciTech Connect

Candidate supernova remnants (SNRs) G23.5+0.1 and G25.5+0.0 were observed by XMM-Newton in the course of a snapshot survey of plerionic and composite SNRs in the Galactic plane. In the field of G23.5+0.1, we detected an extended source, {approx}3' in diameter, which we tentatively interpret as a pulsar wind nebula (PWN) of the middle-aged radio pulsar B1830-08 (J1833-0827; P = 85.3 ms, {tau} = 147 kyr, E-dot = 5.8 Multiplication-Sign 10{sup 35} erg s{sup -1}, d = 5.7 kpc), with the PWN luminosity L{sub 0.2-10keV} Almost-Equal-To 5 Multiplication-Sign 10{sup 33} erg s{sup -1} Almost-Equal-To 8 Multiplication-Sign 10{sup -3} E-dot . The pulsar is not resolved in the EPIC images. Our analysis suggests an association between PSR B1830-08 and the surrounding diffuse radio emission. If the radio emission is due to the SNR, then the pulsar must be significantly younger than its characteristic age. Alternatively, the radio emission may come from a relic PWN. The field also contains SGR 1833-0832 and another middle-aged pulsar B1829-08 (J1832-0827; P = 647 ms, {tau} = 161 kyr, E-dot = 9.3 Multiplication-Sign 10{sup 33} erg s{sup -1}, d = 4.7 kpc), none of which are detected in our observation. In the field of G25.5+0.0, which contains the extended TeV source HESS J1837-069, we detected the recently discovered young high-energy pulsar J1838-0655 (P = 70.5 ms, {tau} = 23 kyr, E-dot = 5.5 Multiplication-Sign 10{sup 36} erg s{sup -1}) embedded in a PWN with extent of 1.'3. The unabsorbed pulsar + PWN luminosity is L{sub 2-11keV} Almost-Equal-To 2 Multiplication-Sign 10{sup 34} erg s{sup -1} Almost-Equal-To 4 Multiplication-Sign 10{sup -3} E-dot at an assumed distance of 7 kpc. We also detected another PWN candidate (AX J1837.3-0652) with an extent of 2' and unabsorbed luminosity L{sub 2-10keV} Almost-Equal-To 4 Multiplication-Sign 10{sup 33} erg s{sup -1} at d = 7 kpc. The third X-ray source, located within the extent of the HESS J1837-069, has a peculiar extended radio counterpart, possibly a radio galaxy with a double nucleus or a microquasar. We did not find any evidence of the SNR emission in the G25.5+0.0 field. We provide detailed multiwavelength analysis and identifications of other field sources and discuss robustness of the G25.5+0.0 and G23.5+0.1 classifications as SNRs.

Kargaltsev, O. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Schmitt, B. M.; Pavlov, G. G. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab., University Park, PA 16802 (United States); Misanovic, Z. [School of Physics, Monash University, Melbourne, 3800 VIC (Australia)

2012-01-20

126

Electron acceleration by young supernova remnant blast waves  

NASA Technical Reports Server (NTRS)

Some general considerations regarding relativistic particle acceleration by young supernova remnants are reviewed. Recent radio observations of supernova remnants apparently locate the bounding shock and exhibit large electron density gradients which verify the presence of strong particle scattering. The radio 'rim' in Tycho's remnant has been found to contain a predominantly radial magnetic field. This may be attributable to an instability of the shock surface and a progress report on an investigation of the stability of strong shocks in partially ionized media is presented.

Blandford, R. D.

1992-01-01

127

Reacceleration of electrons in supernova remnants  

NASA Astrophysics Data System (ADS)

Context. The radio spectra of many shell-type supernova remnants show deviations from those expected on theoretical grounds. Aims: In this paper we determine the effect of stochastic reacceleration on the spectra of electrons in the GeV band and at lower energies, and we investigate whether reacceleration can explain the observed variation in radio spectral indices. Methods: We explicitely calculated the momentum diffusion coefficient for 3 types of turbulence expected downstream of the forward shock: fast-mode waves, small-scale non-resonant modes, and large-scale modes arising from turbulent dynamo activity. After noting that low-energy particles are efficiently coupled to the quasi-thermal plasma, a simplified cosmic-ray transport equation can be formulated and is numerically solved. Results: Only fast-mode waves can provide momentum diffusion fast enough to significantly modify the spectra of particles. Using a synchrotron emissivity that accurately reflects a highly turbulent magnetic field, we calculated the radio spectral index and find that soft spectra with index ? ? - 0.6 can be maintained over more than 2 decades in radio frequency, even if the electrons experience reacceleration for only one acceleration time. A spectral hardening is possible but considerably more frequency-dependent. The spectral modification imposed by stochastic reacceleration downstream of the forward shock depends only weakly on the initial spectrum provided by, e.g., diffusive shock acceleration at the shock itself.

Pohl, M.; Wilhelm, A.; Telezhinsky, I.

2015-01-01

128

Supernova remnants across the Hubble sequence  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) are thought to be the primary sites of cosmic ray acceleration in galaxies, and in this thesis we investigate how the properties of radio SNRs---and the physics of particle acceleration---depend on their parent galaxies. We combine new data with results compiled from the literature to investigate the radio continuum luminosity function of SNRs in 22 nearby galaxies, ranging from dwarf irregulars to luminous starbursts. We find that the luminosity functions can all be modeled with a power law of constant index, and an amplitude which depends on a combination of galaxy star formation rate and interstellar medium (ISM) density. These results can be fit with a simple cartoon model where the magnetic fields in SNRs are significantly amplified above ambient ISM values and the efficiency of cosmic ray acceleration is constant across galaxies. The luminosity of a galaxy's brightest SNR scales with star formation rate, and we find that the Milky Way falls on the measured correlation if we assume a star formation rate of 2 M? yr--1 (synthesized from the literature) and that Cassiopeia A is the most luminous SNR in our Galaxy. As a first step in expanding studies of SNRs to non-star-forming galaxies, we also describe our discovery of an SNR candidate in a globular cluster around the gas-poor S0 galaxy NGC 7457.

Chomiuk, Laura Beth

129

MODIFIED EQUIPARTITION CALCULATION FOR SUPERNOVA REMNANTS  

SciTech Connect

Determination of the magnetic field strength in the interstellar medium is one of the more complex tasks of contemporary astrophysics. We can only estimate the order of magnitude of the magnetic field strength by using a few very limited methods. Besides the Zeeman effect and Faraday rotation, the equipartition or minimum-energy calculation is a widespread method for estimating magnetic field strength and energy contained in the magnetic field and cosmic-ray particles by using only the radio synchrotron emission. Despite its approximate character, it remains a useful tool, especially when there are no other data about the magnetic field in a source. In this paper, we give a modified calculation that we think is more appropriate for estimating magnetic field strengths and energetics in supernova remnants (SNRs). We present calculated estimates of the magnetic field strengths for all Galactic SNRs for which the necessary observational data are available. The Web application for calculation of the magnetic field strengths of SNRs is available at http://poincare.matf.bg.ac.rs/{approx}arbo/eqp/.

Arbutina, B.; Urosevic, D.; Andjelic, M. M.; Pavlovic, M. Z. [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11000 Belgrade (Serbia); Vukotic, B., E-mail: arbo@math.rs [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia)

2012-02-10

130

Discovery of optical candidate supernova remnants in Sagittarius  

NASA Astrophysics Data System (ADS)

During an [O III] survey of planetary nebulae, we identified a region in Sagittarius containing several candidate supernova remants (SNRs) and obtained deep optical narrow-band images and spectra to explore their nature. We obtained images of the area of interest by acquiring observations in the emission lines of H? + [N II], [S II] and [O III]. The resulting mosaic covers an area of 1.4 1.0, where both filamentary and diffuse emission was discovered, suggesting that there is more than one SNR in the area. Deep long-slit spectra were also taken of eight different regions. Both the flux-calibrated images and the spectra show that the emission from the filamentary structures originates from shock-heated gas, while the photo-ionization mechanism is responsible for the diffuse emission. Part of the optical emission is found to be correlated with the radio at 4850 MHz suggesting that they are related, while the infrared emission found in the area at 12 ?m and 22 ?m marginally correlates with the optical. The presence of the [O III] emission line in one of the candidate SNRs implies that the shock velocities in the interstellar "clouds" are between 120 km s-1 and 200 km s-1, while its absence in the other candidate SNRs indicates that the shock velocities there are slower. For all candidate remnants, the [S II] ?? 6716/6731 ratio indicates that the electron densities are below 240 cm-3, while the H? emission is measured to be between 0.6 and 41 10-17 erg s-1 cm-2 arcsec-2. The existence of eight pulsars within 1.5 of the center of the candidate SNRs also implies that there are many SNRs in the area as well as that the detected optical emission could be part of a number of supernovae explosions.

Alikakos, J.; Boumis, P.; Christopoulou, P. E.; Goudis, C. D.

2012-08-01

131

X-ray evidence for electron-ion equilibrium and ionization nonequilibrium in young supernova remnants  

NASA Technical Reports Server (NTRS)

The A-2 spectroscopy experiment on HEAO 1 detected X-ray emission up to 25 keV from the supernova remnants Cas A and Tycho. The spectra must include continuum components with effective temperature equivalent or 10 to the 8th power K which could arise from optically thin plasmas in the collisionless shock fronts. This is the first indication of electron-ion temperature equilibrium in the expanding shell of young remnants. Measurements of the equivalent widths of the K alpha and K beta iron line blends in Cas A, show that their ratio is not compatible with the measured X-ray temperature in the collisional ionization equilibrium model. The search for hard X-ray pulsars in both remnants was unsuccessful.

Pravdo, S. H.; Smith, B. W.

1979-01-01

132

Gamma-Ray Observations of Supernova Remnants  

NASA Astrophysics Data System (ADS)

Despite the growing evidence for shock acceleration of electrons in supernova remnants (SNR), there is still no direct evidence pointing unambiguously to SNR as sources of cosmic-ray nuclei. Observations of nonthermal synchrotron emission in the limbs of a number of shell-type SNR (SN1006, Tycho, Cas A, IC443, RCW86, and Kepler) provide convincing evidence for acceleration of electrons to energies greater than 10 TeV (Allen 1999). The CANGAROO group has now reported significant VHE gamma-ray emission from SN1006 (Tanimori et al. 1998) and RXJ1713-3946, and the HEGRA group has reported preliminary evidence for TeV emission from Cas A (Plhofer et al. 1999); all of these measurements are consistent with the expected level of inverse-Compton emission in these objects. Following the predictions of an observable ?^0-decay signal from nearby SNRs (e.g., Drury, Aharonian and Volk 1994) the discovery of >100 MeV emission from the direction of a number of SNR by the EGRET experiment (Esposito et al. 1996) and possible evidence for a ?^0 component (Gaisser, Protheroe and Stanev 1996) led to some initial optimism that evidence for a SNR origin of cosmic-ray nuclei had been obtained. However, 200 GeV to 100 TeV measurements revealed no significant emission implying either a significantly steeper source spectrum than the canonical ~ E-2.1, a spectral cutoff below the knee energy in these sources, or that a re-interpretation of the EGRET results was required. I will discuss these results, as well as the considerable promise of future gamma-ray experiments to determine the sources of galactic cosmic-ray nuclei and to provide quantitative information about the acceleration mechanisms.

Buckley, James

2000-04-01

133

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the "knee" energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the "knee" energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Professor Steve Reynolds

2006-02-13

134

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Reynolds, Steve (North Carolina State University) [North Carolina State University

2006-02-13

135

Nonthermal X-ray emission from young Supernova Remnants  

E-print Network

The cosmic-ray spectrum up to the knee ($E\\sim 10^{15}$ eV) is attributed to acceleration processes taking place at the blastwaves which bound supernova remnants. Theoretical predictions give a similar estimate for the maximum energy which can be reached at supernova remnant shocks by particle acceleration. Electrons with energies of the order $\\sim 10^{15}$ eV should give a nonthermal X-ray component in young supernova remnants. Recent observations of SN1006 and G347.3-0.5 confirm this prediction. We present a method which uses hydrodynamical simulations to describe the evolution of a young remnant. These results are combined with an algorithm which simultaneously calculates the associated particle acceleration. We use the test particle approximation, which means that the back-reaction on the dynamics of the remnant by the energetic particles is neglected. We present synchrotron maps in the X-ray domain, and present spectra of the energies of the electrons in the supernova remnant. Some of our results can be compared directly with earlier semi-analytical work on this subject by Reynolds [1].

Eric van der Swaluw; Abraham Achterberg; Yves A. Gallant

2000-12-18

136

A BROADBAND STUDY OF THE EMISSION FROM THE COMPOSITE SUPERNOVA REMNANT MSH 11-62  

SciTech Connect

MSH 11-62 (G291.0-0.1) is a composite supernova remnant for which radio and X-ray observations have identified the remnant shell as well as its central pulsar wind nebula. The observations suggest a relatively young system expanding into a low-density region. Here, we present a study of MSH 11-62 using observations with the Chandra, XMM -Newton, and Fermi observatories, along with radio observations from the Australia Telescope Compact Array. We identify a compact X-ray source that appears to be the putative pulsar that powers the nebula, and show that the X-ray spectrum of the nebula bears the signature of synchrotron losses as particles diffuse into the outer nebula. Using data from the Fermi Large Area Telescope, we identify {gamma}-ray emission originating from MSH 11-62. With density constraints from the new X-ray measurements of the remnant, we model the evolution of the composite system in order to constrain the properties of the underlying pulsar and the origin of the {gamma}-ray emission.

Slane, Patrick; Castro, Daniel; Foight, Dillon, E-mail: slane@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138-1516 (United States); and others

2012-04-20

137

A Broadband Study of the Emission from the Composite Supernova Remnant MSH 11-62  

NASA Technical Reports Server (NTRS)

MSH 11-62 (G29U)-Q.1) is a composite supernova remnant for which radio and X-ray observations have identified the remnant shell as well as its central pulsar wind nebula. The observations suggest a relatively young system expanding into a low-density region. Here, we present a study of MSH ll-62 using observations with the Chandra, XMM-Newton, and Fermi observatories, along with radio observations from the Australia Telescope Compact Array. We identify a compact X-ray source that appears to be the putative pulsar that powers the nebula, and show that the X-ray spectrum of the nebula bears the signature of synchrotron losses as particles diffuse into the outer nebula. Using data from the Fermi Large Area Telescope, we identify gamma-ray emission originating from MSH 11-62. With density constraints from the new X-ray measurements of the remnant, we model the evolution of the composite system in order to constrain the properties of the underlying pulsar and the origin of the gamma-ray emission.

Slane, Patrick; Hughes, John P.; Temim, Tea; Rousseau, Romain; Castro, Daniel; Foight, Dillon; Gaensler, B. M.; Funk, Stefan; Lemoine-Goumard, Marianne; Gelfand, Joseph D.; Moffett, David A.

2012-01-01

138

Cosmic ray positrons from a local, middle-aged supernova remnant  

E-print Network

We argue that the cosmic ray positron excess observed in ATIC-2, Fermi LAT, PAMELA, HESS and recently in the precision AMS-02 experiment can be attributed to the production in a local, middle-aged supernova remnant (SNR). Using the prediction of our model of cosmic ray acceleration in SNR we estimate that the SNR responsible for the observed positron excess is located between 250 and 320pc from the Sun and is 170-380 kyear old. The most probable candidate for such a source is the SNR which gave birth to the well-known Geminga pulsar, but is no longer visible. Other contenders are also discussed.

Erlykin, Anatoly

2013-01-01

139

THE YOUNGEST KNOWN X-RAY BINARY: CIRCINUS X-1 AND ITS NATAL SUPERNOVA REMNANT  

E-print Network

Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: ...

Heinz, S.

140

A HIRES analysis of the FIR emission of supernova remnants  

NASA Technical Reports Server (NTRS)

The high resolution (HiRes) algorithm has been used to analyze the far infrared emission of shocked gas and dust in supernova remnants. In the case of supernova remnant IC 443, we find a very good match between the resolved features in the deconvolved images and the emissions of shocked gas mapped in other wavelengths (lines of H2, CO, HCO+, and HI). Dust emission is also found to be surrounding hot bubbles of supernova remnants which are seen in soft X-ray maps. Optical spectroscopy on the emission of the shocked gas suggests a close correlation between the FIR color and local shock speed, which is a strong function of the ambient (preshock) gas density. These provide a potentially effective way to identify regions of strong shock interaction, and thus facilitate studies of kinematics and energetics in the interstellar medium.

Wang, Zhong

1994-01-01

141

Ultraviolet observations of the peculiar supernova remnant in NGC 4449  

NASA Technical Reports Server (NTRS)

IUE spectra were obtained of the emission region in the irregular galaxy NGC 4449 that has been identified as a young, oxygen-rich supernova remnant embedded in an H II region. The spectra show a blue continuum with a strong C IV 1550 P Cygni feature. Comparison to spectral standard stars observed with IUE shows similarities to O3-O7 V and early B Ia stars, indicating that massive young stars are present in the H II region. This comparison also indicates that the ultraviolet extinction in NGC 4449 may be peculiar. Careful inspection of the line-by-line data reveals a broad emission feature at 1657 A that may be semiforbidden O III emission from the supernova remnant. These observations are used in conjunction with shock model calculations to estimate limits on the relative abundances of carbon, silicon, and oxygen in the supernova remnant.

Blair, W. P.; Raymond, J. C.; Gull, T. R.; Fesen, R. A.

1984-01-01

142

A multiwavelength investigation of the supernova remnant IC 443  

NASA Astrophysics Data System (ADS)

Multiwavelength observations of the supernova remnant IC 443 at radio, infrared, optical, ultraviolet, and X-ray wavelengths are presented. This morphological study of IC 443 presents a detailed picture of an adolescent supernova remnant in a multiphase interstellar medium. Radio observations show that better than 80 percent of the continuum emission at 18 cm is in a large-scale (greater than 18 arcmin) component. Decomposition of the infrared data shows that radiatively heated dust, shocked blackbody dust emission, and infrared line emission are all important components of the observed IRAS fluxes. The morphology of the IC 443 region is consistent with a supernova blast in an interstellar medium with a nonuniform distribution of clouds. The bright northeast rim and the great extent of the remnant to the southwest are most easily explained by a cloud filling factor which is greatest in the northeast and falls off toward the southwest.

Mufson, S. L.; McCollough, M. L.; Dickel, J. R.; Petre, R.; White, R.; Chevalier, R.

1986-12-01

143

ROSAT PSPC and HRI Observations of Supernova Remnant G292.0+1.8  

NASA Technical Reports Server (NTRS)

The supernova remnant G292.0+1.8 was observed by the ROSAT PSPC for 18 ksec as part of this grant. Considerable effort was put into the analysis of the PSPC spectra. The major work went into nonequilibrium ionization joint spectral fits with the Einstein SSS and EXOSAT ME data which indicated that the two spatial regions of this remnant (a central bar and a plateau region covering a larger extent) had similar abundances, but different excitation conditions (temperature and ionization state), an important conclusion, if true. Unfortunately as this work was being finished, new ASCA data revealed the presence of a previously unknown, spectrally hard X-ray source near the center of the remnant which contaminated the SSS and ME data and as a consequence made our detailed spectral analysis done up until then un-publishable. We searched for evidence of this hard source in the PSPC data both spectrally and using timing searches (for a pulsar), but found nothing significant. ROSAT HRI data were also obtained on this remnant. These data were compared to the Einstein HRI data to search for evidence of spectral variations with position and possible expansion of the X-ray remnant. One feature in the remnant appears to have changed in brightness although it is not clear what is the cause of the change. No evidence for the hard ASCA source was apparent in the HRI data.

Hughes, John P.

1999-01-01

144

Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant  

E-print Network

We present far-ultraviolet observations of the Antlia supernova remnant obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR). The strongest lines observed are C IV 1548,1551 and C III 977. The C IV emission of this mixed-morphology supernova remnant shows a clumpy distribution, and the line intensity is nearly constant with radius. The C III 977 line, though too weak to be mapped over the whole remnant, is shown to vary radially. The line intensity peaks at about half the radius, and drops at the edge of the remnant. Both the clumpy distribution of C IV and the rise in the C IV to C III ratio towards the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.

Jong-Ho Shinn; Kyoung Wook Min; Ravi Sankrit; Kwang-Sun Ryu; Il-Joong Kim; Wonyong Han; Uk-Won Nam; Jang-Hyun Park; Jerry Edelstein; Eric J. Korpela

2007-10-09

145

Supernova Remnants as the Sources of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays holds still many mysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmic rays. For this conference devoted to the Astronomical Institute Utrecht I put the emphasis on work that was done in my group, but placed in a broader context: efficient cosmic-ray acceleration and the implications for cosmic-ray escape, synchrotron radiation and the evidence for magnetic-field amplification, potential X-ray synchrotron emission from cosmic-ray precursors, and I conclude with the implications of cosmic-ray escape for a Type Ia remnant like Tycho and a core-collapse remnant like Cas A.

Vink, J.

2013-01-01

146

New Galactic supernova remnants discovered with IPHAS  

NASA Astrophysics Data System (ADS)

As part of a systematic search programme of a 10 wide strip of the northern Galactic plane, we present preliminary evidence for the discovery of four (and possibly five) new supernova remnants (SNRs). The pilot search area covered the 19-20 h right ascension zone sampling from +20 to +55 in declination using binned mosaic images from the Isaac Newton Telescope Photometric H? Survey (IPHAS). The optical identification of the candidate SNRs was based mainly on their filamentary and arc-like emission morphologies, their apparently coherent, even if fractured, structure and clear disconnection from any diffuse neighbouring H II region type nebulosity. Follow-up optical spectroscopy was undertaken, sampling carefully across prominent features of these faint sources. The resulting spectra revealed typical emission-line ratios for shock-excited nebulae which are characteristic of SNRs, which, along with the latest diagnostic diagrams, strongly support the likely SNR nature of these sources: G038.7-1.3 (IPHASX J190640.5+042819), G067.6+0.9 (IPHASX J195744.9+305306), G066.0-0.0 (IPHASX J195749.2+290259) and G065.8-0.5 (IPHASX J195920.4+283740). A fifth possible younger, higher density nebula SNR candidate, G067.8+0.5 (IPHASX J200002.4+305035), was discovered 5 arcmin to the west of IPHASX J195744.9+305306, and it warrants further study. A multiwavelength cross-check from available archived data in the regions of these candidates was also performed with a focus on possible radio counterparts. A close positional match between previously unrecognized radio structures at several frequencies and across various components of the H? optical image data was found for all SNR candidates. This lends further direct support for the SNR nature of these objects. Evolved SNRs may have very weak and/or highly fragmented radio emission which could explain why they had not been previously recognized, but the association becomes clear in combination with the optical emission.

Sabin, L.; Parker, Q. A.; Contreras, M. E.; Olgun, L.; Frew, D. J.; Stupar, M.; Vzquez, R.; Wright, N. J.; Corradi, R. L. M.; Morris, R. A. H.

2013-05-01

147

SUPERNOVA REMNANT PROGENITOR MASSES IN M31  

SciTech Connect

Using Hubble Space Telescope photometry, we age-date 59 supernova remnants (SNRs) in the spiral galaxy M31 and use these ages to estimate zero-age main-sequence masses (M{sub ZAMS}) for their progenitors. To accomplish this, we create color-magnitude diagrams (CMDs) and employ CMD fitting to measure the recent star formation history of the regions surrounding cataloged SNR sites. We identify any young coeval population that likely produced the progenitor star, then assign an age and uncertainty to that population. Application of stellar evolution models allows us to infer the M{sub ZAMS} from this age. Because our technique is not contingent on identification or precise location of the progenitor star, it can be applied to the location of any known SNRs. We identify significant young star formation around 53 of the 59 SNRs and assign progenitor masses to these, representing a factor of {approx}2 increase over currently measured progenitor masses. We consider the remaining six SNRs as either probable Type Ia candidates or the result of core-collapse progenitors that have escaped their birth sites. In general, the distribution of recovered progenitor masses is bottom-heavy, showing a paucity of the most massive stars. If we assume a single power-law distribution, dN/dM{proportional_to}M{sup {alpha}}, then we find a distribution that is steeper than a Salpeter initial mass function (IMF) ({alpha} = -2.35). In particular, we find values of {alpha} outside the range -2.7 {>=} {alpha} {>=} -4.4 to be inconsistent with our measured distribution at 95% confidence. If instead we assume a distribution that follows a Salpeter IMF up to some maximum mass, then we find that values of M{sub Max} > 26 are inconsistent with the measured distribution at 95% confidence. In either scenario, the data suggest that some fraction of massive stars may not explode. The result is preliminary and requires more SNRs and further analysis. In addition, we use our distribution to estimate a minimum mass for core collapse between 7.0 and 7.8 M{sub Sun }.

Jennings, Zachary G.; Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.; Fouesneau, Morgan; Weisz, Daniel R. [Department of Astronomy, University of Washington Seattle, Box 351580, WA 98195 (United States); Murphy, Jeremiah W. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Dolphin, Andrew E., E-mail: zachjenn@uw.edu, E-mail: adolphin@raytheon.com [Raytheon, 1151 East Hermans Road, Tucson, AZ 85706 (United States)

2012-12-10

148

Two new Perseus arm supernova remnants discovered in the Canadian Galactic Plane Survey  

NASA Astrophysics Data System (ADS)

We report the discovery of two new second-quadrant supernova remnants, G96.0+2.0 and G113.0+0.2, in the data of the Canadian Galactic Plane Survey. The two SNRs are residents of the Perseus spiral arm at distances of 4.0 kpc and 3.1 kpc, respectively. The distances were determined kinematically by associating the objects with neutral hydrogen and molecular material. G96.0+2.0 is most likely located at the edge of a large stellar wind bubble with a systemic velocity of about -44 km s-1. It consists of a relatively bright shell where the shock is encountering the wall of H I and slowly fades away towards the interior of the stellar wind bubble. The visible part of the remnant has a diameter of about 30 pc and a radio spectral index of ? ? -0.66 (S ?^?), indicating that it is a shell-type remnant in an early stage of development. The SNR is most likely the remnant of a type Ib/c supernova explosion. G113.0+0.2 is located in an area of confusing thermal emission not far from the radio-bright supernova remnant Cassiopeia A. It has an unusual elongated structure consisting of a long polarized filament and a more complex head structure that is interacting with a small molecular cloud; it resides in a butterfly-shaped H I cavity, probably a stellar wind bubble. It is about 36 pc long and 15 pc wide at a position angle of 70 with the Galactic Plane. A pulsar with a relatively low period derivative, giving it a characteristic age of 10 million years, is located close to the centre of the radio continuum emission at a Perseus arm distance. Whether the pulsar is the result of the same supernova explosion that created G113.0+0.2 or if it was left behind by an earlier supernova that also shaped the stellar wind bubble remains uncertain.

Kothes, R.; Uyan?ker, B.; Reid, R. I.

2005-12-01

149

GSH 90-28-17: a possible old supernova remnant  

NASA Astrophysics Data System (ADS)

GSH 90-28-17 is a high-latitude Galactic H I supershell, identified in the H I supershell catalogues with a velocity vlsr -17 km s-1. We used the new Galactic Arecibo L-band Feed Array (GALFA) H I survey data, which have much higher resolution and sensitivity than was previously available, to re-examine the properties of the supershell. We derived a new distance of 400 pc for GSH 90-28-17 and suggested that it is related to the Lac OB1 association. The radius of GSH 90-28-17 is 66.0 3.5 pc. The H I mass of the shell is (3.1 0.1) 104 M?. It has an age of 4.5 Myr and a total kinetic energy of (8.2 0.3) 1048 erg. We extracted radio continuum data for the GSH 90-28-17 region from the 408-MHz All-Sky Survey and Bonn 1420-MHz survey and filtered the diffuse background Galactic emission. A radio loop-like ridge is found to be associated with the H I shell at both frequencies and shows a non-thermal origin, with a temperature-temperature (TT)-plot index of ? = -1.35 0.69. In addition, the pulsar J2307+2225, with a similar distance, is found in the shell region. We conclude that GSH 90-28-17 is probably an old, type II supernova remnant in the solar neighbourhood.

Xiao, L.; Zhu, M.

2014-02-01

150

Suzaku studies of the supernova remnant CTB 109 hosting the magnetar 1E 2259+586  

NASA Astrophysics Data System (ADS)

Ages of the magnetar 1E 2259+586 and the associated supernova remnant CTB 109 were studied. Analyzing the Suzaku data of CTB 109, its age was estimated to be 14 kyr, which is much younger than the measured characteristic age of 1E 2259+586, 230 kyr. This reconfirms the previously reported age discrepancy of this magnetar/remnant association, and suggests that the characteristic ages of magnetars are generally over-estimated as compared to their true ages. This discrepancy is thought to arise because the former are calculated without considering decay of the magnetic fields. This novel view is supported independently by much stronger Galactic-plane concentration of magnetars than other pulsars. The process of magnetic field decay in magnetars is mathematically modeled. It is implied that magnetars are much younger objects than previously considered, and can dominate new-born neutron stars.

Nakano, Toshio; Murakami, Hiroaki; Makishima, Kazuo; Hiraga, Junoko S.; Uchiyama, Hideki; Kaneda, Hidehiro; Enoto, Teruaki

2015-02-01

151

Hot interstellar tunnels. 1: Simulation of interacting supernova remnants  

NASA Technical Reports Server (NTRS)

The theory required to build a numerical simulation of interacting supernova remnants is developed. The hot cavities within a population of remnants will become connected, with varying ease and speed, for a variety of assumed conditions in the outer shells of old remnants. Apparently neither radiative cooling nor thermal conduction in a large-scale galactic magnetic field can destroy hot cavity regions, if they grow, faster than they are reheated by supernova shock waves, but interstellar mass motions disrupt the contiguity of extensive cavities necessary for the dispersal of these shocks over a wide volume. Monte Carlo simulations show that a quasi-equilibrium is reached in the test space within 10 million yrs of the first supernova and is characterized by an average cavity filling fraction of the interstellar volume. Aspects of this equilibrium are discussed for a range of supernova rates. Two predictions are not confirmed within this range: critical growth of hot regions to encompass the entire medium, and the efficient quenching of a remnant's expansion by interaction with other cavities.

Smith, B. W.

1976-01-01

152

On the origin of two-shell supernova remnants  

E-print Network

The proper motion of massive stars could cause them to explode far from the geometric centers of their wind-driven bubbles and thereby could affect the symmetry of the resulting diffuse supernova remnants. We use this fact to explain the origin of SNRs consisting of two partially overlapping shells (e.g. Cygnus Loop, 3C 400.2, etc.).

V. V. Gvaramadze

2007-12-27

153

A NEW EVOLUTIONARY PHASE OF SUPERNOVA REMNANT 1987A  

E-print Network

We have been monitoring the supernova remnant (SNR) 1987A with Chandra observations since 1999. Here we report on the latest change in the soft X-ray light curve of SNR 1987A. For the last ~1.5 yr (since day ~8000), the ...

Park, Sangwook

154

TWO NEW XRAY/OPTICAL / RADIO SUPERNOVA REMNANTS M31  

E-print Network

region. precisely registered images reveal optical shells with X­ray counterparts. These shells have: individual ( supernova remnants techniques: image processing INTRODUCTION spatial resolution Chandra X­Ray date back Rubin (1972), X­ray surveys to van Speybroeck (1979). Without digital imaging allow

Sjouwerman, Loránt

155

HIGH-ENERGY EMISSION FROM THE COMPOSITE SUPERNOVA REMNANT MSH 15-56  

SciTech Connect

MSH 15-56 (G326.3-1.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that reveal a compact source at the tip of the radio PWN and complex structures that provide evidence for mixing of the supernova (SN) ejecta with PWN material following a reverse shock interaction. The X-ray spectra are well fitted by a non-thermal power-law model whose photon index steepens with distance from the presumed pulsar, and a thermal component with an average temperature of 0.55 keV. The enhanced abundances of silicon and sulfur in some regions, and the similar temperature and ionization timescale, suggest that much of the X-ray emission can be attributed to SN ejecta that have either been heated by the reverse shock or swept up by the PWN. We find one region with a lower temperature of 0.3 keV that appears to be in ionization equilibrium. Assuming the Sedov model, we derive a number of SNR properties, including an age of 16,500 yr. Modeling of the {gamma}-ray emission detected by Fermi shows that the emission may originate from the reverse shock-crushed PWN.

Temim, Tea [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Slane, Patrick; Plucinsky, Paul P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Castro, Daniel [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Gelfand, Joseph [New York University Abu Dhabi (United Arab Emirates); Dickel, John R., E-mail: tea.temim@nasa.gov [Physics and Astronomy Department, University of New Mexico, MSC 07-4220, Alburquerque, NM 87131 (United States)

2013-05-01

156

High-energy Emission from the Composite Supernova Remnant MSH 15-56  

NASA Technical Reports Server (NTRS)

MSH 1556 (G326.3-1.8) is a composite supernova remnant (SNR) that consists of an SNR shell and a displaced pulsar wind nebula (PWN) in the radio. We present XMM-Newton and Chandra X-ray observations of the remnant that reveal a compact source at the tip of the radio PWN and complex structures that provide evidence for mixing of the supernova (SN) ejecta with PWN material following a reverse shock interaction. The X-ray spectra are well fitted by a non-thermal power-law model whose photon index steepens with distance from the presumed pulsar, and a thermal component with an average temperature of 0.55 keV. The enhanced abundances of silicon and sulfur in some regions, and the similar temperature and ionization timescale, suggest that much of the X-ray emission can be attributed to SN ejecta that have either been heated by the reverse shock or swept up by the PWN. We find one region with a lower temperature of 0.3 keV that appears to be in ionization equilibrium.Assuming the Sedov model, we derive a number of SNR properties, including an age of 16,500 yr. Modeling of the gamma-ray emission detected by Fermi shows that the emission may originate from the reverse shock-crushed PWN.

Temim, Tea; Slane, Patrick; Castro, Daniel; Plucinsky, Paul; Gelfand, Joseph; Dickel, John R.

2013-01-01

157

Extended OH(1720 MHz) Maser Emission from Supernova Remnants  

E-print Network

Compact OH(1720 MHz) masers have proven to be excellent signposts for the interaction of supernova remnants with adjacent molecular clouds. Less appreciated has been the weak, extended OH(1720 MHz) emission which accompanies strong compact maser sources. Recent single-dish and interferometric observations reveal the majority of maser-emitting supernova remnants have accompanying regions of extended maser emission. Enhanced OH abundance created by the passing shock is observed both as maser emission and absorption against the strong background of the remnant. Modeling the observed OH profiles gives an estimate of the physical conditions in which weak, extended maser emission arises. I will discuss how we can realize the utility of this extended maser emission, particularly the potential to measure the strength of the post-shock magnetic field via Zeeman splitting over these large-scales.

J. W. Hewitt; F. Yusef-Zadeh; M. Wardle; D. A. Roberts

2007-05-21

158

Stochastic Electron Acceleration in Shell-Type Supernova Remnants II  

NASA Astrophysics Data System (ADS)

We discuss the generic characteristics of stochastic particle acceleration by a fully developed turbulence spectrum and show that resonant interactions of particles with high speed waves dominate the acceleration process. To produce the relativistic electrons inferred from the broadband spectrum of a few well-observed shell-type supernova remnants in the leptonic scenario for the TeV emission, fast mode waves must be excited effectively in the downstream and dominate the turbulence in the subsonic phase. Strong collisionless non-relativistic astrophysical shocks are studied with the assumption of a constant Aflvn speed. The energy density of non-thermal electrons is found to be comparable to that of the magnetic field. With reasonable parameters, the model explains observations of shell-type supernova remnants. More detailed studies are warranted to better understand the nature of supernova shocks.

Liu, Siming; Fan, Zhong-Hui; Fryer, Christopher L.

2008-12-01

159

G0.9 + 0.1 and the emerging class of composite supernova remnants  

NASA Technical Reports Server (NTRS)

High-resolution, multifrequency maps of a bright extended radio source near the Galactic center have revealed it to be a classic example of a composite supernova remnant. A steep-spectrum shell of emission, about 8 arcmin in diameter, surrounds a flat-spectrum, highly polarized Crab-like core about 2 arcmin across. The two components have equal flux densities at about 6 cm, marking this source as having the highest core-to-shell ratio among the about 10 composite remnants identified to date. X-ray and far-infrared data on the source are used to constrain the energetics and evolutionary state of the remnant and its putative central pulsar. It is argued that the total energy contained in the Crab-like components requires that the pulsars powering them were all born with periods shorter than 50 ms, and that if a substantial number of neutron stars with slow initial rotation rates exist, their birthplaces have not yet been found.

Helfand, D. J.; Becker, R. H.

1987-01-01

160

X-ray studies of supernova remnants: A different view of supernova explosions  

PubMed Central

The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research. PMID:20404206

Badenes, Carles

2010-01-01

161

X-ray studies of supernova remnants: a different view of supernova explosions.  

PubMed

The unprecedented spatial and spectral resolutions of Chandra have revolutionized our view of the X-ray emission from supernova remnants. The excellent datasets accumulated on young, ejecta-dominated objects like Cas A or Tycho present a unique opportunity to study at the same time the chemical and physical structure of the explosion debris and the characteristics of the circumstellar medium sculpted by the progenitor before the explosion. Supernova remnants can thus put strong constraints on fundamental aspects of both supernova explosion physics and stellar evolution scenarios for supernova progenitors. This view of the supernova phenomenon is completely independent of, and complementary to, the study of distant extragalactic supernovae at optical wavelengths. The calibration of these two techniques has recently become possible thanks to the detection and spectroscopic follow-up of supernova light echoes. In this paper, I review the most relevant results on supernova remnants obtained during the first decade of Chandra and the impact that these results have had on open issues in supernova research. PMID:20404206

Badenes, Carles

2010-04-20

162

Modelling Hard Gamma-Ray Emission from Supernova Remnants  

NASA Technical Reports Server (NTRS)

The observation by the CANGAROO (Collaboration of Australia and Nippon Gamma Ray Observatory at Outback) experiment of TeV emission from SN 1006, in conjunction with several instances of non-thermal X-ray emission from supernova remnants, has led to inferences of super-TeV electrons in these extended sources. While this is sufficient to propel the theoretical community in their modelling of particle acceleration and associated radiation, the anticipated emergence in the next decade of a number of new experiments probing the TeV and sub-TeV bands provides further substantial motivation for modellers. In particular, the quest for obtaining unambiguous gamma-ray signatures of cosmic ray ion acceleration defines a "Holy Grail" for observers and theorists alike. This review summarizes theoretical developments in the prediction of MeV-TeV gamma-rays from supernova remnants over the last five years, focusing on how global properties of models can impact, and be impacted by, hard gamma-ray observational programs, thereby probing the supernova remnant environment. Properties of central consideration include the maximum energy of accelerated particles, the density of the unshocked interstellar medium, the ambient magnetic field, and the relativistic electron-to-proton ratio. Criteria for determining good candidate remnants for observability in the TeV band are identified.

Baring, Matthew G.

1999-01-01

163

Modelling Hard Gamma-Ray Emission from Supernova Remnants  

NASA Technical Reports Server (NTRS)

The observation by the CANGAROO experiment of TeV emission from SN 1006, in conjunction with several instances of non-thermal X-ray emission from supernova remnants, has led to inferences of super-TeV electrons in these extended sources. While this is sufficient to propel the theoretical community in their modelling of particle acceleration and associated radiation, the anticipated emergence in the next decade of a number of new experiments probing the TeV and sub-TeV bands provides further substantial motivation for modellers. In particular, the quest for obtaining unambiguous gamma-ray signatures of cosmic ray ion acceleration defines a "Holy Grail" for observers and theorists alike. This review summarizes theoretical developments in the prediction of MeV-TeV gamma-rays from supernova remnants over the last five years, focusing on how global properties of models can impact, and be impacted by, hard gamma-ray observational programs, thereby probing the supernova remnant environment. Properties of central consideration include the maximum energy of accelerated particles, the density of the unshocked interstellar medium, the ambient magnetic field, and the relativistic electron-to-proton ratio. Criteria for determining good candidate remnants for observability in the TeV band are identified.

Baring, Matthew

2000-01-01

164

A Newly Recognized Very Young Supernova Remnant in M83  

NASA Astrophysics Data System (ADS)

As part of a spectroscopic survey of supernova remnant candidates in M83 using the Gemini-South telescope and GMOS, we have discovered one object whose spectrum shows very broad lines at Halpha, [O I] 6300, and [O III] 5007, similar to those from other objects classified as `late time supernovae.' Although six historical supernovae have been observed in M83 since 1923, none were seen at the location of this object. Hubble Space Telescope Wide Field Camera 3 images show a nearly unresolved emission source, while Chandra and ATCA data reveal a bright X-ray source and nonthermal radio source at the position. Objects in other galaxies showing similar spectra are only decades post-supernova, which raises the possibility that the supernova that created this object occurred during the last century but was not observed. Using photometry of nearby stars from the HST data, we suggest the precursor was at least 17 M(sun), and the presence of broad Halpha in the spectrum makes a type II supernova likely. The supernova must predate the 1983 VLA radio detection of the object. We suggest examination of archival images of M83 to search for evidence of the supernova event that gave rise to this object, and thus provide a precise time since the explosion.We acknowledge STScI grants under the umbrella program ID GO-12513 to Johns Hopkins University, STScI, and Middlebury College. PFW acknowledges additional support from the National Science Foundation through grant AST-0908566.

Blair, William P.; Winkler, P. Frank; Long, Knox S.; Whitmore, Bradley C.; Kim, Hwihyun; Soria, Roberto; Kuntz, K. D.; Plucinsky, Paul P.; Dopita, Michael A.; Stockdale, Christopher

2015-01-01

165

A Newly Recognized Very Young Supernova Remnant in M83  

NASA Astrophysics Data System (ADS)

As part of a spectroscopic survey of supernova remnant candidates in M83 using the Gemini-South telescope and Gemini Multi-Object Spectrograph, we have discovered one object whose spectrum shows very broad lines at H?, [O I] ??6300, 6363, and [O III] ??4959, 5007, similar to those from other objects classified as "late time supernovae". Although six historical supernovae have been observed in M83 since 1923, none were seen at the location of this object. Hubble Space Telescope (HST) Wide Field Camera 3 images show a nearly unresolved emission source, while Chandra and ATCA data reveal a bright X-ray source and nonthermal radio source at the position. Objects in other galaxies showing similar spectra are only decades post-supernova, which raises the possibility that the supernova that created this object occurred during the last century but was missed. Using photometry of nearby stars from the HST data, we suggest the precursor was at least 17 M ?, and the presence of broad H? in the spectrum makes a type II supernova likely. The supernova must predate the 1983 Very Large Array radio detection of the object. We suggest examination of archival images of M83 to search for evidence of the supernova event that gave rise to this object, and thus provide a precise age. Based on observations made with NASA's Chandra X-Ray Observatory, which is operated by the Smithsonian Astrophysical Observatory under contract # NAS83060, with data obtained through program GO1-12115.

Blair, William P.; Winkler, P. Frank; Long, Knox S.; Whitmore, Bradley C.; Kim, Hwihyun; Soria, Roberto; Kuntz, K. D.; Plucinsky, Paul P.; Dopita, Michael A.; Stockdale, Christopher

2015-02-01

166

A 3D numerical model for Kepler's supernova remnant  

NASA Astrophysics Data System (ADS)

We present new 3D numerical simulations for Kepler's supernova remnant. In this work we revisit the possibility that the asymmetric shape of the remnant in X-rays is the product of a Type Ia supernova explosion which occurs inside the wind bubble previously created by an AGB companion star. Due to the large peculiar velocity of the system, the interaction of the strong AGB wind with the interstellar medium results in a bow shock structure. In this new model we propose that the AGB wind is anisotropic, with properties such as mass-loss rate and density having a latitude dependence, and that the orientation of the polar axis of the AGB star is not aligned with the direction of motion. The ejecta from the Type Ia supernova explosion is modelled using a power-law density profile, and we let the remnant evolve for 400 yr. We computed synthetic X-ray maps from the numerical results. We find that the estimated size and peculiar X-ray morphology of Kepler's supernova remnant are well reproduced by considering an AGB mass-loss rate of 10-5 M? yr-1, a wind terminal velocity of 10 km s-1, an ambient medium density of 10-3 cm-3 and an explosion energy of 7 1050 erg. The obtained total X-ray luminosity of the remnant in this model reaches 6 1050 erg, which is within a factor of 2 of the observed value, and the time evolution of the luminosity shows a rate of decrease in recent decades of 2.4 per cent yr-1 that is consistent with the observations.

Toledo-Roy, J. C.; Esquivel, A.; Velzquez, P. F.; Reynoso, E. M.

2014-07-01

167

Analysis of Shock Interactions and Supernova Morphology from Molecular Emission Around Young Supernova Remnants  

NASA Astrophysics Data System (ADS)

We have observed the supernova remnant Cassiopeia A (Cas A) in the mid-infrared from 10-40 microns with the Spitzer Space Telescope and at millimeter wavelengths in 12CO and 13CO J=2-1 (230 and 220 GHz) with the Heinrich Hertz Submillimeter Telescope (HHSMT). Broadened (6 - 10 km/s) CO emission in the millimeter indicates that some molecular clouds towards the line of sight of the Cas A shock front have been shock broadened by ejecta from the remnant. The IR spectra demonstrate high-velocity emission along the northern shock front of the remnant coincident with bright radio continuum emission. These features trace a direct interaction with the Cas A shock front. Furthermore, some of the broadened molecular emission extends 1 - 2 arcminutes beyond the furthest extent of the SNR shock front. We infer from the proximity to the remnant as well as the positions of broadened CO emission that this material is accelerated by ejecta with velocity significantly larger than the observed free-expansion velocity of the Cas A shock front. This observation is consistent with a bipolar outflow as well as fast-moving ejecta pistons inferred in the Cas A remnant, in particular along the southwest to northeast axis of the remnant. We extend this type of analysis to other young, galactic supernova remnants in order to place constraints on the morphology and shock interactions during supernova events.

Kilpatrick, Charles; Bieging, J. H.; Rieke, G.

2014-01-01

168

Chandra X-Ray Observatory Photo Album: G11.2-0.3 Chandra Associates Pulsar and Historic Supernova  

NSDL National Science Digital Library

NASA's Chandra X-Ray Observatory, designed to observe X-rays from high energy regions of the universe, regularly releases images taken using the Advanced CCD Imaging Spectrometer (ACIS). This image shows a pulsar located exactly at the geometric center of the supernova remnant known as G11.2-0.3. The image is accompanied by a table giving the scale, category, coordinates, observation date and time, color code, and instrument used.

169

Understanding hadronic gamma-ray emission from supernova remnants  

E-print Network

We aim to test the plausibility of a theoretical framework in which the gamma-ray emission detected from supernova remnants may be of hadronic origin, i.e., due to the decay of neutral pions produced in nuclear collisions involving relativistic nuclei. In particular, we investigate the effects induced by magnetic field amplification on the expected particle spectra, outlining a phenomenological scenario consistent with both the underlying Physics and the larger and larger amount of observational data provided by the present generation of gamma experiments, which seem to indicate rather steep spectra for the accelerated particles. In addition, in order to study to study how pre-supernova winds might affect the expected emission in this class of sources, the time-dependent gamma-ray luminosity of a remnant with a massive progenitor is worked out. Solid points and limitations of the proposed scenario are finally discussed in a critical way.

Damiano Caprioli

2011-05-06

170

Galactic Propagation of Cosmic Rays from Individual Supernova Remnants  

E-print Network

It is widely believed that supernova remnants are the best candidate sources for the observed cosmic ray flux up to the knee, i.e. up to ~PeV energies. Indeed, the gamma-ray spectra of some supernova remnants can be well explained by assuming the decay of neutral pions which are created in hadronic interactions. Therefore, fitting the corresponding gamma spectra allows us to derive the spectra of cosmic rays at the source which are locally injected into our Galaxy. Using these spectra as a starting point, we propagate the cosmic rays through the Galaxy using the publicly available GALPROP code. Here, we will present first results on the contribution of those SNRs to the total cosmic ray flux and discuss implications.

Nierstenhoefer, Nils; Schuppan, Florian; Tjus, Julia Becker

2015-01-01

171

35 cm observations of a sample of large supernova remnants  

NASA Astrophysics Data System (ADS)

We present radio maps of ten large-diameter supernova remnants observed at 35 cm wavelength with the Effelsberg 100-m telescope. The angular resolution is 14farcm5 . The sources are G126.2+1.6, G127.1+0.5, HB3, HB9, S147, IC 443, Cygnus Loop, W63 and HB21. For each object we give an integrated flux density and improved spectra when necessary. We also present a map of G213.0-0.6, which we tentatively identify as a new large supernova remnant with a very low surface brightness, apparently interacting with the H Ii region S284. Based on observations with the Effelsberg 100-m telescope operated by the Max-Planck-Institut fr Radioastronomie (MPIfR), Bonn, Germany.

Reich, W.; Zhang, X.; Frst, E.

2003-09-01

172

Molecular emission in the IC443 Supernova Remnant  

NASA Astrophysics Data System (ADS)

Supernovae are an important source of energy input to the interstellar medium. They send shock waves that propagate through and interact with the Interstellar Medium. These shock waves originally create large cavities filled with hot ionized material. At some point, supernova-driven shock waves become radiative, emitting strong line emissions, initially at optical and ultraviolet wavelengths, that are widely observed from supernova remnants. In the interaction region of these remnants with the ambient molecular cloud, slower shock waves heat, accelerate, and compress the surrounding medium. The physical processes at work in such shocked regions (density, temperature and associated timescales) in turn generate a specific chemistry, both in the gas-phase and through grains interactions, that can significantly alter the abundance of certain species. The resulting infra-red, but also sub-mm molecular emission can be used as a diagnostic tool to study the physical and chemical characteristics of the shocked region, yielding constraints on shock parameters such as the pre-shock density, magnetic field, or shock type, velocity or type. IC443 is a typical example of such galactic SuperNova Remnants, at an estimated distance of 1.5 kpc, with a diameter of about 50 arcminutes. In this talk, I will present new extensive maps of CO gas of the whole remnant, at the highest frequencies accessible from the ground. I will also explain how the use of such observations on selected positions, in combination with pure rotational H_2 transitions acquired with the Spitzer telescope (IRS) can allow us to place constraints on shock model parameters through comparisons with a grid of shock models. Based on this preliminary study, I will also show how the additional comparison of water observations (as provided by the HIFI receiver onboard the Herschel telescope) with our shock simulations is a good way to refine these constraints and test our understanding of the water formation processes in shocked regions.

Gusdorf, A.; Gusten, R.; Yuan, Y.; Neufeld, D.; Herschel Wadi Team

2011-05-01

173

Chandra observations of Tychos supernova remnant  

Microsoft Academic Search

We present a newChandra observation of Tychos supernova remnant with the Advanced CCD Imaging Spectrometer. Multicolor Xray imaging reveals new\\u000a details of the outer shock and ejecta. At energies between 4 and 6 keV, the outline of the outer shock is clearly revealed\\u000a in X-rays for the first time. The distribution of the emission from lines of Si and Fe

U. Hwang; R. Petre; A. E. Szymkowiak; S. S. Holt

2002-01-01

174

Fermi Large Area Telescope Detection of Supernova Remnant RCW 86  

NASA Astrophysics Data System (ADS)

Using 5.4 yr Fermi Large Area Telescope data, we report the detection of GeV ?-ray emission from the shell-type supernova remnant RCW 86 (G315.4-2.3) with a significance of ~5.1?. The data slightly favors an extended emission of this supernova remnant. The spectral index of RCW 86 is found to be very hard, ? ~ 1.4, in the 0.4-300 GeV range. A one-zone leptonic model can well fit the multi-wavelength data from radio to very high energy ?-rays. The very hard GeV ?-ray spectrum and the inferred low gas density seem to disfavor a hadronic origin for the ?-rays. The ?-ray behavior of RCW 86 is very similar to several other TeV shell-type supernova remnants, e.g., RX J1713.7-3946, RX J0852.0-4622, SN 1006, and HESS J1731-347.

Yuan, Qiang; Huang, Xiaoyuan; Liu, Siming; Zhang, Bing

2014-04-01

175

Neutron star/supernova remnant associations: the view from Tbilisi  

E-print Network

We propose a new approach for studying the neutron star/supernova remnant associations, based on the idea that the supernova remnants (SNRs) can be products of an off-centered supernova (SN) explosion in a preexisting bubble created by the wind of a moving massive star. A cavity SN explosion of a moving star results in a considerable offset of the neutron star (NS) birth-place from the geometrical center of the SNR. Therefore: a) the high transverse velocities inferred for a number of NSs through their association with SNRs can be reduced; b) the proper motion vector of a NS should not necessarily point away from the geometrical center of the associated SNR. Taking into account these two facts allow us to enlarge the circle of possible NS/SNR associations, and could significantly affect the results of previous studies of associations. The possibilities of our approach are illustrated with some examples. We also show that the concept of an off-centered cavity SN explosion could be used to explain the peculiar structures of a number of SNRs and for searches for stellar remnants possibly associated with them.

V. V. Gvaramadze

2002-08-01

176

Are the Models for Type Ia Supernova Progenitors Consistent with the Properties of Supernova Remnants?  

E-print Network

We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circumstellar medium has on the evolution of the ensuing supernova remnant. We compare our simulations with the observational properties of known Type Ia supernova remnants in the Galaxy (Kepler, Tycho, SN 1006), the Large Magellanic Cloud (0509-67.5, 0519-69.0, N103B), and M31 (SN 1885). We find that optically thick outflows from the white dwarf surface (sometimes known as accretion winds) with velocities above 200 km/s excavate large low-density cavities around the progenitors. Such large cavities are incompatible with the dynamics of the forward shock and the X-ray emission from the shocked ejecta in all the Type Ia remnants that we have examined.

Carles Badenes; John P. Hughes; Eduardo Bravo; Norbert Langer

2007-03-13

177

The Kinematics of Kepler's Supernova Remnant as Revealed by Chandra  

NASA Astrophysics Data System (ADS)

I have determined the expansion of the supernova remnant of SN 1604 (Kepler's supernova) based on archival Chandra ACIS-S observations made in 2000 and 2006. The measurements were done in several distinct energy bands, and were made for the remnant as a whole, and for six individual sectors. The average expansion parameter indicates that the remnant expands on average as r~t0.5, but there are significant differences in different parts of the remnant: the bright northwestern part expands as r~t0.35, whereas the rest of the remnant's expansion shows an expansion r~t0.6. The latter is consistent with an explosion in which the outer part of the ejecta has a negative power law slope for density (?~v-n) of n=7, or with an exponential density profile [?~exp(-v/ve)]. The expansion parameter in the southern region, in conjunction with the shock radius, indicates a rather low value (<51050 erg) for the explosion energy of SN 1604 for a distance of 4 kpc. A higher explosion energy is consistent with the results if the distance is larger. The filament in the eastern part of the remnant, which is dominated by X-ray synchrotron radiation, seems to mark a region with a fast shock speed r~t0.7, corresponding to a shock velocity of v=4200 km s-1, for a distance to SN 1604 of 4 kpc. This is consistent with the idea that X-ray synchrotron emission requires shock velocities in excess of ~2000 km s-1. The X-ray-based expansion measurements reported are consistent with results based on optical and radio measurements but disagree with previous X-ray measurements based on ROSAT and Einstein observations.

Vink, Jacco

2008-12-01

178

OXYGEN-RICH SUPERNOVA REMNANT IN THE LARGE MAGELLANIC CLOUD  

NASA Technical Reports Server (NTRS)

This is a NASA Hubble Space Telescope image of the tattered debris of a star that exploded 3,000 years ago as a supernova. This supernova remnant, called N132D, lies 169,000 light-years away in the satellite galaxy, the Large Magellanic Cloud. A Hubble Wide Field Planetary Camera 2 image of the inner regions of the supernova remnant shows the complex collisions that take place as fast moving ejecta slam into cool, dense interstellar clouds. This level of detail in the expanding filaments could only be seen previously in much closer supernova remnants. Now, Hubble's capabilities extend the detailed study of supernovae out to the distance of a neighboring galaxy. Material thrown out from the interior of the exploded star at velocities of more than four million miles per hour (2,000 kilometers per second) plows into neighboring clouds to create luminescent shock fronts. The blue-green filaments in the image correspond to oxygen-rich gas ejected from the core of the star. The oxygen-rich filaments glow as they pass through a network of shock fronts reflected off dense interstellar clouds that surrounded the exploded star. These dense clouds, which appear as reddish filaments, also glow as the shock wave from the supernova crushes and heats the clouds. Supernova remnants provide a rare opportunity to observe directly the interiors of stars far more massive than our Sun. The precursor star to this remnant, which was located slightly below and left of center in the image, is estimated to have been 25 times the mass of our Sun. These stars 'cook' heavier elements through nuclear fusion, including oxygen, nitrogen, carbon, iron etc., and the titanic supernova explosions scatter this material back into space where it is used to create new generations of stars. This is the mechanism by which the gas and dust that formed our solar system became enriched with the elements that sustain life on this planet. Hubble spectroscopic observations will be used to determine the exact chemical composition of this nuclear- processed material, and thereby test theories of stellar evolution. The image shows a region of the remnant 50 light-years across. The supernova explosion should have been visible from Earth's southern hemisphere around 1,000 B.C., but there are no known historical records that chronicle what would have appeared as a 'new star' in the heavens. This 'true color' picture was made by superposing images taken on 9-10 August 1994 in three of the strongest optical emission lines: singly ionized sulfur (red), doubly ionized oxygen (green), and singly ionized oxygen (blue). Photo credit: Jon A. Morse (STScI) and NASA Investigating team: William P. Blair (PI; JHU), Michael A. Dopita (MSSSO), Robert P. Kirshner (Harvard), Knox S. Long (STScI), Jon A. Morse (STScI), John C. Raymond (SAO), Ralph S. Sutherland (UC-Boulder), and P. Frank Winkler (Middlebury). Image files in GIF and JPEG format may be accessed via anonymous ftp from oposite.stsci.edu in /pubinfo: GIF: /pubinfo/GIF/N132D.GIF JPEG: /pubinfo/JPEG/N132D.jpg The same images are available via World Wide Web from links in URL http://www.stsci.edu/public.html.

2002-01-01

179

A Newly Recognized Very Young Supernova Remnant in M83  

E-print Network

As part of a spectroscopic survey of supernova remnant candidates in M83 using the Gemini-South telescope and GMOS, we have discovered one object whose spectrum shows very broad lines at H$\\alpha$, [O~I] 6300,6363, and [O~III] 4959,5007, similar to those from other objects classified as `late time supernovae.' Although six historical supernovae have been observed in M83 since 1923, none were seen at the location of this object. Hubble Space Telescope Wide Field Camera 3 images show a nearly unresolved emission source, while Chandra and ATCA data reveal a bright X-ray source and nonthermal radio source at the position. Objects in other galaxies showing similar spectra are only decades post-supernova, which raises the possibility that the supernova that created this object occurred during the last century but was missed. Using photometry of nearby stars from the HST data, we suggest the precursor was at least 17 $\\rm M_{sun}$, and the presence of broad H$\\alpha$ in the spectrum makes a type II supernova likely....

Blair, William P; Long, Knox S; Whitmore, Bradley C; Kim, Hwihyun; Soria, Roberto; Kuntz, K D; Plucinsky, Paul P; Dopita, Michael A; Stockdale, Christopher

2015-01-01

180

On the environments and progenitors of supernova remnants associated with highly magnetized neutron stars  

E-print Network

The distinction between the high-magnetic field pulsars (HBPs, thought to be mainly rotation-powered) and magnetars (commonly believed to be powered by their super-strong magnetic fields) has been recently blurred with the discovery of magnetar-like activity from the HBP J1846-0258 in the Supernova Remnant (SNR) Kes 75. What determines the spin properties of a neutron star at birth and its manifestation as a magnetar-like or more classical pulsar is still not clear. Furthermore, although a few studies have suggested very massive progenitors for magnetars, there is currently no consensus on the progenitors of these objects. To address these questions, we examine their environments by studying or revisiting their securely associated SNRs. Our approach is by: 1) inferring the mass of their progenitor stars through X-ray spectroscopic studies of the thermally emitting supernova ejecta, and 2) investigating the physical properties of their hosting SNRs and ambient conditions. We here highlight our detailed studies...

Safi-Harb, Samar

2012-01-01

181

THE MORPHOLOGY AND DYNAMICS OF JET-DRIVEN SUPERNOVA REMNANTS: THE CASE OF W49B  

E-print Network

The circumstellar medium (CSM) of a massive star is modified by its winds before a supernova (SN) explosion occurs, and thus the evolution of the resulting supernova remnant (SNR) is influenced by both the geometry of the ...

Gonzlez-Casanova, Diego F.

182

Discriminating the progenitor type of supernova remnants with Iron K-shell emission  

E-print Network

Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ...

Yamaguchi, Hiroya

183

CONSTRAINING EXPLOSION TYPE OF YOUNG SUPERNOVA REMNANTS USING 24 ?m EMISSION MORPHOLOGY  

E-print Network

Determination of the explosion type of supernova remnants (SNRs) can be challenging, as SNRs are hundreds to thousands of years old and supernovae are classified based on spectral properties days after explosion. Previous ...

Peters, Charee L.

184

The Fascinating High-Energy World of Neutron Stars and Supernova Remnants  

NASA Astrophysics Data System (ADS)

The past few years have witnessed a fast growth in the high-energy astrophysics community in Canada, thanks to new opportunities including the University Faculty Award (UFA) program introduced by the Natural Sciences and Engineering Research Council of Canada (NSERC) to appoint promising female researchers to faculty positions in science and engineering. As a UFA fellow at the University of Manitoba, I have had the unique opportunity to contribute to the launch of a new astronomy program in the department of Physics (renamed to Physics and Astronomy). My research focuses on observational studies of neutron stars, pulsar wind nebulae, and supernova remnants. The study of these exotic objects helps address the physics of the extreme and probe some of the most energetic events in the Universe. I will highlight exciting discoveries in this field and some of the questions to be addressed with current and future high-energy missions.

Safi-Harb, Samar

2006-06-01

185

Uncovering The Properties of Young Neutron Stars and Their Surrounding Supernova A Remnants  

NASA Technical Reports Server (NTRS)

In the third year of this program, the following studies have been undertaken in support of this effort: G292.0+1.8: In our previous work on this SNR, we discovered a young neutron star and its associated pulsar wind nebula. Radio observations by Camilo et al. (2002) have identified a young 136 ms pulsar in the direction of G292.0+1.8. We have used Chandra HRC observations of the central source to identify X-ray pulsations at the same period, thus establishing the neutron star as the radio pulsar counterpart. We have also set limits on the cooling of this young neutron star based on the unpulsed component of the X-ray emission. We find that the limit falls slightly below standard cooling models in which the modified Urca process is responsible for the bulk of the interior neutrino emission. A paper summarizing these results is currently being circulated amongst co-authors for review prior to publication. 3c 58: Our Chandra observations of this Crab-like SNR revealed the presence of a young, rapidly rotating pulsar as well as a central compact nebula which we interpret as a toroidal structure associated with the pulsar wind termination shock. Our modeling of this structure has allowed us to establish a temperature upper limit for the neutron star which falls well below predictions from standard cooling models, and implies the presence of exotic particles (such as pion condensates) or other processes that increase the neutrino production rate in the interior. A paper summarizing this work has been published in the Astrophysical Journal (Slane, Helfand, & Murray 2002, ApJ, 571, L45), and the results were the subject of a NASA Space Science Update (4/10/2002) which led to extensive media coverage. Based upon our initial observations, we submitted a successful Chandra Large Project proposal for a 350 ks observation of this young neutron star and its wind nebula. Kes 79: Our Chandra observations of this SNR reveal a compact central source which appears to be the neutron star formed in the explosion that produced the remnant. There is no evidence for a surrounding pulsar wind nebula. The source properties are similar to the central source in Cas A even though the Kes 79 remnant is considerably older. The results have been published in the Astrophysical Journal (Seward, Slane, Smith, and Sun 2003, ApJ, 584,414). Chandra Survey for Compact Objects in Supernova Remnants: We have formed a collaboration to carry out an extensive search for young neutron stars in nearby supernova remnants. Using X-ray observations from an approved Chandra Large Project, as well as from additional approved XMM observations, we are investigating a volume-limited sample of SNRs for which there is currently no evidence of associated neutron stars. We have obtained extensive optical and 1R data to complement the project, and analysis of these data is currently underway.

Slane, Patrick O.; Oliversen, Ronald J. (Technical Monitor)

2003-01-01

186

X-Ray Measured Dynamics of Tycho's Supernova Remnant  

NASA Technical Reports Server (NTRS)

We present X-ray proper-motion measurements of the forward shock and reverse-shocked ejecta in Tycho's supernova remnant, based on three sets of archival Chandra data taken in 2000, 2003, and 2007. We find that the proper motion of the edge of the remnant (i.e., the forward shock and protruding ejecta knots) varies from 0.''20 yr-1 (expansion index m = 0.33, where R = tm ) to 0.''40 yr-1 (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr-1 (m = 0.26) to 0.''40 yr-1 (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of [approx]0.5 are consistent with those derived from radio observations. We also find proper motion and expansion index of the reverse-shocked ejecta to be 0.''21-0.''31 yr-1 and 0.43-0.64, respectively. From a comparison of the measured m-value with Type Ia supernova evolutionary models, we find a pre-shock ambient density around the remnant of [less, similar]0.2 cm-3.

Katsuda, Satoru; Petre, Robert; Hughes, John; Hwang, Una; Yamaguchi, Hiroya; Hayato, Asami; Mori, Koji; Tsunemi, Hiroshi

2010-01-01

187

Radio polarization observations of large supernova remnants at ?6 cm  

NASA Astrophysics Data System (ADS)

We have observed 79 supernova remnants (SNRs) with the Urumqi 25 m telescope at ?6 cm during the Sino-German ?6 cm polarization survey of the Galactic plane. We measured flux densities of SNRs at ?6 cm, some of which are the first ever measured or the measurements at the highest frequency, so that we can determine or improve spectra of SNRs. Our observations have ruled out spectral breaks or spectral flattening that were suggested for a few SNRs, and confirmed the spectral break of S147. By combining our ?6 cm maps with ?11 cm and ?21 cm maps from the Effelsberg 100 m telescope, we calculated the spectral index maps of several large SNRs. For many remnants we obtained for the first time polarization images, which show the intrinsic magnetic field structures at ?6 cm. We disapproved three objects as being SNRs, OA184, G192.8-1.1 and G16.8-1.1, which show a thermal spectrum and no polarization. We have discovered two large supernova remnants, G178.2-4.2 and G25.1-2.3., in the survey maps.

Han, J. L.; Gao, X. Y.; Sun, X. H.; Reich, W.; Xiao, L.; Reich, P.; Xu, J. W.; Shi, W. B.; Frst, E.; Wielebinski, R.

2014-01-01

188

The dynamic evolution of the Kepler supernova remnant  

NASA Astrophysics Data System (ADS)

Two supernovae exploding events were observed visually from the same position, the north of Tian-Jian in Wei-Suei (the north of 42 Theta Ophiuchi), in 1604 and 1664, respectively, and were recorded in the ancient astronomical literatures of China and Korea. However, in recent years only one supernova remnant (SNR) has been identified in this position using advanced optical, radio and X-ray techniques. Some observed information for the Kepler SNR, including its nonspherically symmetric emission property with brighter north but darker south, have been shown. It is conjectured that a supernova outburst in 1664 was excited by the 1604 supernova explosion at a distance of about 0.5 parsecs. The present SNR is formed from the summation of these two explosions. The dynamical evolution of the Kepler SNR is studied by means of a time-dependent, hydrodynamic code in the present paper. The density, velocity, temperature, and X-ray emission distribution of the SNR are shown, being the results of dynamic evolution for 380 years following the explosion of the supernova in 1604. Compared with present radio and X-ray observations, these numerical results may reasonably explain the observational features.

Tang, Z.-M.

1986-07-01

189

12. Blast waves and supernova remnants 12.1 Self-similarity and scales  

E-print Network

12. Blast waves and supernova remnants 12.1 Self-similarity and scales In galaxies one finds a many can arise from strong stellar winds and from stellar explosions, supernova. Supernovae are caused by run-away thermonuclear reactions that occur when stellar cores collapse. A type I supernova involves

Pohl, Martin Karl Wilhelm

190

Destruction of Interstellar Dust in Evolving Supernova Remnant Shock Waves  

NASA Astrophysics Data System (ADS)

Supernova generated shock waves are responsible for most of the destruction of dust grains in the interstellar medium (ISM). Calculations of the dust destruction timescale have so far been carried out using plane parallel steady shocks, however, that approximation breaks down when the destruction timescale becomes longer than that for the evolution of the supernova remnant (SNR) shock. In this paper we present new calculations of grain destruction in evolving, radiative SNRs. To facilitate comparison with the previous study by Jones et al., we adopt the same dust properties as in that paper. We find that the efficiencies of grain destruction are most divergent from those for a steady shock when the thermal history of a shocked gas parcel in the SNR differs significantly from that behind a steady shock. This occurs in shocks with velocities ?200 km s?1 for which the remnant is just beginning to go radiative. Assuming SNRs evolve in a warm phase dominated ISM, we find dust destruction timescales are increased by a factor of ?2 compared to those of Jones et al., who assumed a hot gas dominated ISM. Recent estimates of supernova rates and ISM mass lead to another factor of ?3 increase in the destruction timescales, resulting in a silicate grain destruction timescale of ?23 Gyr. These increases, while not able to resolve the problem of the discrepant timescales for silicate grain destruction and creation, are an important step toward understanding the origin and evolution of dust in the ISM.

Slavin, Jonathan D.; Dwek, Eli; Jones, Anthony P.

2015-04-01

191

Supernova remnant revolution in an inhomogeneous medium. I - Numerical models  

NASA Technical Reports Server (NTRS)

The first numerical simulations of supernova remnant evolution in an inhomogeneous gas are presented. Evolution in the lowest density substrate (the intercloud) is assumed to be spherically symmetric with a large intercloud filling factor and many dense regions (clouds) within the remnant; however, mass momentum and energy transfer between cloud and intercloud are included and the position and morphology of individual clouds tracked. Evolution is considered in several different models of the interstellar medium, both those in which the intercloud gas is diffuse (0.001 to 0.01/cu cm) and those in which it is relatively dense (n approximately 0.3/cu cm) under a variety of assumptions about the efficiency of thermal evaporation from the clouds into the intercloud medium.

Cowie, L. L.; Mckee, C. F.; Ostriker, J. P.

1981-01-01

192

A compressed cloud in the Vela supernova remnant  

NASA Technical Reports Server (NTRS)

Strong interstellar absorption lines of C I, arising from the two excited fine-structure levels, are found in IUE observations of HD 72350 (type B4 III). An analysis of the excited-level populations of C I gives local temperature and pressure limits, and auxiliary data on the limit of column density for excited O I and the carbon ionization help to establish that (1) the local temperature is within the limits of 25-100 K, and (2) the pressure/Boltzmann's constant ratio is at least 10 to the 4.3/cu cm K, despite its small size. This high-pressure cloud is discussed in terms of shock compression by the Vela supernova blast wave, along with the relationship of this kind of cloud compression to star formation and to the origin of the characteristic filamentary emission arcs seen in Vela and other supernova remnants

Jenkins, E. B.; Silk, J.; Leep, E. M.; Wallerstein, G.

1981-01-01

193

Gamma-Ray Emission From Crushed Clouds in Supernova Remnants  

SciTech Connect

It is shown that the radio and gamma-ray emission observed from newly-found 'GeV-bright' supernova remnants (SNRs) can be explained by a model, in which a shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are simultaneously compressed by the supernova blastwave as a result of formation of a radiative cloud shock. Simple reacceleration of pre-existing CRs is generally sufficient to power the observed gamma-ray emission through the decays of {pi}{sup 0}-mesons produced in hadronic interactions between high-energy protons (nuclei) and gas in the compressed-cloud layer. This model provides a natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC 443 with flat radio spectral index, which can be ascribed to a combination of secondary and reaccelerated electrons and positrons.

Uchiyama, Yasunobu; Blandford, Roger D.; Funk, Stefan; /SLAC; Tajima, Hiroyasu; /Nagoya U., Solar-Terrestrial Environ. Lab.; Tanaka, Takaaki; /KIPAC, Menlo Park; ,

2010-10-27

194

EVOLUTION OF SYNCHROTRON X-RAYS IN SUPERNOVA REMNANTS  

SciTech Connect

A systematic study of the synchrotron X-ray emission from supernova remnants (SNRs) has been conducted. We selected a total of 12 SNRs whose synchrotron X-ray spectral parameters are available in the literature with reasonable accuracy and studied how their luminosities change as a function of radius. It is found that the synchrotron X-ray luminosity tends to drop especially when the SNRs become larger than {approx}5 pc, despite large scatter. This may be explained by the change of spectral shape caused by the decrease of the synchrotron roll-off energy. A simple evolutionary model of the X-ray luminosity is proposed and is found to reproduce the observed data approximately, with reasonable model parameters. According to the model, the total energy of accelerated electrons is estimated to be 10{sup 47-48} erg, which is well below the supernova explosion energy. The maximum energies of accelerated electrons and protons are also discussed.

Nakamura, Ryoko; Bamba, Aya; Dotani, Tadayasu; Ishida, Manabu [ISAS/JAXA Department of High Energy Astrophysics, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Yamazaki, Ryo [Department of Physics and Mathematics, Aoyama-Gakuin University, 5-10-1 Fuchinobe, Sagamihara, Kanagawa 252-5258 (Japan); Kohri, Kazunori [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan)

2012-02-20

195

Evolution of Synchrotron X-rays in Supernova Remnants  

E-print Network

A systematic study of the synchrotron X-ray emission from supernova remnants (SNRs) has been conducted. We selected a total of 12 SNRs whose synchrotron X-ray spectral parameters are available in the literature with reasonable accuracy, and studied how their luminosities change as a function of radius. It is found that the synchrotron X-ray luminosity tends to drop especially when the SNRs become larger than ~5 pc, despite large scatter. This may be explained by the change of spectral shape caused by the decrease of the synchrotron roll-off energy. A simple evolutionary model of the X-ray luminosity is proposed and is found to reproduce the observed data approximately, with reasonable model parameters. According to the model, the total energy of accelerated electrons is estimated to be 10^(47-48) ergs, which is well below the supernova explosion energy. The maximum energies of accelerated electrons and protons are also discussed.

Ryoko Nakamura; Aya Bamba; Tadayasu Dotani; Manabu Ishida; Ryo Yamazaki; Kazunori Kohri

2011-12-05

196

Biermann mechanism in primordial supernova remnants and seed magnetic fields  

NASA Astrophysics Data System (ADS)

We have studied the generation of magnetic fields by the Biermann mechanism in the pair-instability supernovae explosions of the first stars. The Biermann mechanism produces magnetic fields in the shocked region between the bubble and interstellar medium (ISM), even if magnetic fields are absent initially. We have performed a series of two-dimensional magnetohydrodynamic simulations with the Biermann term and estimate the amplitude and total energy of the produced magnetic fields. We find that magnetic fields with amplitude 10-14-10-17 G are generated inside the bubble, though the amount of magnetic fields generated depend on specific values of initial conditions. This corresponds to magnetic fields with total energy of 1028-1031 erg per each supernova remnant, which is strong enough to be the seed magnetic field for a galactic and/or interstellar dynamo.

Hanayama, H.; Takahashi, K.; Kotake, K.; Oguri, M.; Ichiki, K.; Ohno, H.

2006-06-01

197

Biermann Mechanism in Primordial Supernova Remnant and Seed Magnetic Fields  

NASA Astrophysics Data System (ADS)

We study the generation of magnetic fields by the Biermann mechanism in the supernova explosions of the first stars. The Biermann mechanism produces magnetic fields in the shocked region between the bubble and interstellar medium (ISM), even if magnetic fields are absent initially. We perform a series of two-dimensional magnetohydrodynamic simulations with the Biermann term and estimate the amplitude and total energy of the magnetic fields that are produced. We find that magnetic fields with amplitude 10-14 to 10-17 G are generated inside the bubble, although the amount of magnetic field generated depends on the specific values of the initial conditions. This corresponds to magnetic fields of 1028-1031 ergs for each supernova remnant, which is strong enough to be the seed magnetic field for a galactic and/or interstellar dynamo.

Hanayama, Hidekazu; Takahashi, Keitaro; Kotake, Kei; Oguri, Masamune; Ichiki, Kiyotomo; Ohno, Hiroshi

2005-11-01

198

An X-ray study of the supernova remnant G20.0-0.2 and its surroundings  

NASA Astrophysics Data System (ADS)

Aims: We study the supernova remnant G20.0-0.2 and its surroundings to look for the high-energy counterpart of the radio nebula and to find evidence of interaction between the shock front and the interstellar medium. Methods: We used Chandra archival observations to analyze the X-ray emission from the supernova remnant. The surrounding gas was investigated using data extracted from the Galactic Ring Survey, the VLA Galactic Plane Survey, the Galactic Legacy Infrared Midplane Survey Extraordinaire, and the Bolocam Galactic Plane Survey. Results: G20.0-0.2 shows diffuse X-ray emission from the central region of the radio remnant. Although the current data do not allow us to distinguish between a thermal or non-thermal origin for the X-ray diffuse emission, based on the radio properties we suggest a synchrotron origin as the most favorable. The hard X-ray point source CXO J182807.4-113516 appears located at the geometrical center of the remnant and is a potential candidate to be the pulsar powering the nebula. We found a molecular cloud adjacent to the flattest border of G20.0-0.2, indicating a probable interaction between the shock front of the remnant and the molecular gas. Several young stellar object candidates are found located in the brightest region of the molecular emission, as well as over a millimeter continuum source and a dark cloud. This distribution is an indication of an active star-forming region around the supernova remnant.

Petriella, A.; Paron, S. A.; Giacani, E. B.

2013-06-01

199

Supernovae, Landau Levels, and Pulsar Kicks  

E-print Network

We derive the energy asymmetry given the proto-neutronstar during the time when the neutrino sphere is near the surface of the proto-neutron star, using the modified URCA process. The electrons produced with the anti-neutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated in the direction of the magnetic field.

Leonard S. Kisslinger

2006-12-18

200

Forward Shock Proper Motions of Kepler's Supernova Remnant  

NASA Astrophysics Data System (ADS)

The X-ray structure of Kepler's supernova remnant shows a rounded shape delineated by forward shocks. We measure proper motions of the forward shocks on overall rims of the remnant, by using archival Chandra data taken in two epochs with time difference of 6.09 yr. The proper motions of the forward shocks on the northern rim are measured to be 0.076" (+/-0.032" +/-0.016") to 0.11" (+/-0.014" +/-0.016") yr-1, while those on the rest of the rims are measured to be 0.15" (+/-0.017" +/-0.016") to 0.30" (+/-0.048" +/-0.016") yr-1 here the first-term errors are statistical uncertainties and the second-term errors are systematic uncertainties. Combining the best-estimated shock velocity of 1660+/-120 km s-1 measured for Balmer-dominated filaments in the northern and central portions of the remnant (Sankrit et al. 2005) with the proper motions derived for the forward shocks on the northern rim, we estimate a distance of 3.3+1.6-0.4 kpc to the remnant. We measure the expansion indices, m (defined as R~tm), to be 0.47-0.82 for most of the rims. These values are consistent with those expected in Type Ia SN explosion models, in which the ejecta and the circumstellar medium have power-law density profiles whose indices are 5-7 and 0-2, respectively. In addition, we should note the slower expansion on the northern rim than that on the southern rim. This is likely caused by the inhomogeneous circumstellar medium; the density of the circumstellar medium is higher in the north than that in the south of the remnant. The newly estimated geometric center, around which we believe the explosion point exists, is located at ~5" offset to the north of the radio center.

Katsuda, S.; Tsunemi, H.; Uchida, H.; Kimura, M.

2008-12-01

201

A Detailed X-Ray Investigation of PSR J2021+4026 and the ?-Cygni Supernova Remnant  

NASA Astrophysics Data System (ADS)

We have investigated the field around the radio-quiet ?-ray pulsar, PSR J2021+4026, with a ~140 ks XMM-Newton observation and ~56 ks archival Chandra data. Through analyzing the pulsed spectrum, we show that the X-ray pulsation is purely thermal in nature, which suggests that the pulsation originated from a hot polar cap with T ~ 3 106 K on the surface of a rotating neutron star. On the other hand, the power-law (PL) component that dominates the pulsar emission in the hard band is originated from off-pulse phases, which possibly comes from a pulsar wind nebula. In re-analyzing the Chandra data, we have confirmed the presence of a bow-shock nebula that extends from the pulsar to the west by ~10 arcsec. The orientation of this nebular feature suggests that the pulsar is probably moving eastward, which is consistent with the speculated proper motion by extrapolating from the nominal geometrical center of the supernova remnant (SNR) G78.2+2.1 to the current pulsar position. For G78.2+2.1, our deep XMM-Newton observation also enables a study of the central region and part of the southeastern region with superior photon statistics. The column absorption derived for the SNR is comparable to that for PSR J2021+4026, which supports their association. The remnant emission in both of the examined regions is in a non-equilibrium ionization state. Also, the elapsed time of both regions after shock-heating is apparently shorter than the Sedov age of G78.2+2.1. This might suggest that the reverse shock has reached the center not long ago. Apart from PSR J2021+4026 and G78.2+2.1, we have also serendipitously detected an X-ray flash-like event, XMM J202154.7+402855, from this XMM-Newton observation.

Hui, C. Y.; Seo, K. A.; Lin, L. C. C.; Huang, R. H. H.; Hu, C. P.; Wu, J. H. K.; Trepl, L.; Takata, J.; Wang, Y.; Chou, Y.; Cheng, K. S.; Kong, A. K. H.

2015-01-01

202

MHD Interaction of Pulsar Wind Nebulae with SNRs and the ISM  

E-print Network

In the late 1960s the discovery of the Crab pulsar in its associated supernova remnant, launched a new field in supernova remnant research: the study of pulsar-driven or plerionic supernova remnants. In these type of remnants, the relativistic wind emitted by the pulsar, blows a pulsar wind nebula into the interior of its supernova remnant. Now, more then forty years after the discovery of the Crab pulsar, there are more then fifty plerionic supernova remnants known, due to the ever-increasing capacity of observational facilities. I will review our current understanding of the different evolutionary stages of a pulsar wind nebula as it is interacting with its associated supernova remnant.Therefore I will discuss both analytical and more recent numerical (M)HD models.The four main stages of a pulsar wind nebula are: the supersonic expansion stage, the reverse shock interaction stage, the subsonic expansion stage and ultimatelythe stage when the head of the bubble is bounded by a bow shock, due to the supersonic motion of the pulsar. Ultimately this pulsar wind nebula bow shock will break through its associated remnant, after which the pulsar-powered bow shock will interact directly with the interstellar medium. I will discuss recent numerical models from these type of pulsar wind nebulae and their morphology.

Eric van der Swaluw

2005-04-12

203

X-Ray Ejecta Kinematics of the Galactic Core-Collapse Supernova Remnant G292.0+1.8  

NASA Astrophysics Data System (ADS)

We report on the results from the analysis of our 114 ks Chandra High Energy Transmision Grating Spectrometer observation of the Galactic core-collapse supernova remnant G292.0+1.8. To probe the three-dimensional structure of the clumpy X-ray emitting ejecta material in this remnant, we measured Doppler shifts in emission lines from metal-rich ejecta knots projected at different radial distances from the expansion center. We estimate radial velocities of ejecta knots in the range of -2300 lsim vr lsim 1400 km s-1. The distribution of ejecta knots in velocity versus projected-radius space suggests an expanding ejecta shell with a projected angular thickness of ~90'' (corresponding to ~3 pc at d = 6 kpc). Based on this geometrical distribution of the ejecta knots, we estimate the location of the reverse shock approximately at the distance of ~4 pc from the center of the supernova remnant, putting it in close proximity to the outer boundary of the radio pulsar wind nebula. Based on our observed remnant dynamics and the standard explosion energy of 1051 erg, we estimate the total ejecta mass to be lsim8 M ?, and we propose an upper limit of lsim35 M ? on the progenitor's mass.

Bhalerao, Jayant; Park, Sangwook; Dewey, Daniel; Hughes, John P.; Mori, Koji; Lee, Jae-Joon

2015-02-01

204

Shocks in Dense Clouds in the Vela Supernova Remnant: FUSE  

NASA Technical Reports Server (NTRS)

We have obtained 8 LWRS FUSE spectra to study a recently identified interaction of the Vela supernova remnant with a dense cloud region along its western edge. The goal is to quantify the temperature, ionization, density, and abundance characteristics associated with this shock/dense cloud interface by means of UV absorption line studies. Our detection of high-velocity absorption line C I at +90 to +130 km/s with IUE toward a narrow region interior to the Vela SNR strongly suggests the Vela supernova remnant is interacting with a dense ISM or molecular cloud. The shock/dense cloud interface is suggested by (1) the rarity of detection of high-velocity C I seen in IUE spectra, (2) its very limited spatial distribution in the remnant, and (3) a marked decrease in X-ray emission in the region immediately west of the position of these stars where one also finds a 100 micron emission ridge in IRAS images. We have investigated the shock physics and general properties of this interaction region through a focussed UV absorption line study using FUSE spectra. We have FUSE data on OVI absorption lines observed toward 8 stars behind the Vela supernova remnant (SNR). We compare the OVI observations with IUE observations of CIV absorption toward the same stars. Most of the stars, which are all B stars, have complex continua making the extraction of absorption lines difficult. Three of the stars, HD 72088, HD 72089 and HD 72350, however, are rapid rotators (v sin i less than 100 km/s) making the derivation of absorption column densities much easier. We have measured OVI and CIV column densities for the "main component" (i.e. the low velocity component) for these stars. In addition, by removing the H2 line at 1032.35A (121.6 km/s relative to OVI), we find high velocity components of OVI at approximately 150 km/s that we attribute to the shock in the Vela SNR. The column density ratios and magnitudes are compared to both steady shock models and results of hydrodynamical SNR modeling. We find that the models require the shock to be relatively slow (approximately 100 - 170 km/s) to match the FUSE data. We discuss the implications of our results for models of the evolution of the Vela SNR.

Nichols, Joy; Sonneborn, George (Technical Monitor)

2002-01-01

205

An X-ray and optical study of the supernova remnant W44  

NASA Technical Reports Server (NTRS)

We report the results of a 8000 s observation of the supernova remnant W44 using the ROSAT Position Sensitive Proportional Counter (PSPC). The image shows the same centrally peaked morphology observed by the Einstein IPC and contrasts with the shell-like radio morphology. The eastern limb shows a lack of X-ray emission within the radio shell, probably due to the interaction between the Supernova Remnants (SNR) and a molecular cloud. No counterpart to the pulsar 1853 + 01 in W44 has been detected, with L(sub X) less than 1.3 x 10(exp 32) ergs/s in the 0.2 to 2.4 keV band. The spectral analysis of the central part of W44, combining EXOSAT ME and Einstein SSS data, shows that the shocked plasma has not reached ionization equilibrium. The best nonequilibrium fit to PSPC, ME, and SSS spectra gives Eta = 10(exp 51) ergs cm(exp -6), T(sub s) = 10(exp 7) K with T(sub e) = T(sub i), suggesting conditions are approaching ionization equilibrium. There is no evidence of enhanced abundances of Mg, Si, S, or Fe. The variation of temperature and column density was obtained region by region using the PSPC and Einstein IPC. The temperature is largely uniform over the remnant, but strong column density variations are found to be consistent with molecular clouds in the line of sight. An evaporation model with a two-phase interstellar medium structure of clumps and interclump gas (White & Long 1991) can explain the X-ray centrally peaked morphology of W44. The clumps remaining behind a SN shock provide a reservoir of material, and evaporat e to increase the density of X-ray emitting gas in the interior of a SNR. The uniform temperature distribution of W44 strongly supports the predictions of this model. In addition, mosaiced H alpha and (S II) images of W44, taken using the prime focus universal extragalactic instrument (PFUEI) camera on the Palomar 60 sec telescope, reveal the first discovery of optical filaments (both H alpha and (S II)) in the northwestern and southeastern portion of the remnant, within the X-ray emitting region. The optical filaments and the X-ray image showing locally brighter emission and clumps along the filaments suggest both are produced by the interaction between the supernova shock front and regions of enhanced ambient density.

Rho, Jeongee; Petre, R.; Schlegel, Eric M.

1994-01-01

206

Asymmetric Supernovae, Pulsars, Magnetars, and Gamma-Ray Bursts  

Microsoft Academic Search

We outline the possible physical processes, associated timescales, and energetics that could lead to the production of pulsars, jets, asymmetric supernovae, and weak gamma-ray bursts in routine circumstances and to a 1016 G magnetar and perhaps stronger gamma-ray burst in more extreme circumstances in the collapse of the bare core of a massive star. The production of a LeBlanc-Wilson MHD

J. Craig Wheeler; Insu Yi; Peter Hflich; Lifan Wang

2000-01-01

207

The Extraordinary Supernova Remnant in NGC 4449 Revisited  

NASA Astrophysics Data System (ADS)

NGC 4449, a Magellanic-type irregular galaxy at a distance of about 4 Mpc, contains the most luminous known supernova remnant (SNR) in both X-ray and optical bands. Its optical spectrum is characterized by broad lines from O, Ne, S, Ar, and Ca, and its size and expansion velocity (6000 km/s) suggest that the unobserved SN exploded about 65 years ago. The remnants extraordinary brightness can be attributed to the interaction of supernova ejecta with unusually dense and extensive circumstellar material. We will present new Chandra imaging, together with UV/Optical spectra of the SNR from HST/STIS and the MMT. The X-ray luminosity of the SNR is less than when it was detected with Einstein in 1980, but the luminosity and X-ray spectral shape have remained relatively constant over the last 10 years. In the FUV, the HST spectra show for the first time broad line emission from C IV 1550 , as well as Si IV + O IV at 1400 and O III] at 1660 . The new NUV and optical spectra are fairly similar to earlier HST/FOS spectra and to ground-based spectra we have obtained over the last decade. Here we describe these new observations, and our attempts to understand the nature of the progenitor of the SNR.We acknowledge support for this effort from NASA through grant GO-12462 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc, under NASA contract NAS5-26555, and through Chandra Award Number GO9-0075, issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory, under NASA contract NAS8-03060.

Long, Knox S.; Blair, William P.; Fesen, Robert A.; Milisavljevic, Dan; Winkler, P. Frank

2015-01-01

208

The X-ray Iron Emission from Tycho's Supernova Remnant  

E-print Network

We present the results of broadband fits to the X-ray spectrum of Tycho's supernova remnant obtained by the Solid-State Imaging Spectrometers on the ASCA Observatory. We use single-temperature, single-ionization-age, nonequilibrium ionization models to characterize the ejecta and the blast-shocked interstellar medium. Based on the Fe K emission at 6.5 keV, previous spectral studies have suggested that the Fe ejecta in this Type Ia remnant are stratified interior to the other ejecta. The ASCA data provide important constraints from the Fe L emission near 1 keV as well as the Fe K emission. We find that the simplest models, with emission from the ejecta and blast wave each at a single temperature and ionization age, severely underestimate the Fe K flux. We show that there is little Fe emission associated with the Si and S ejecta shell. The blast-shocked interstellar medium has abundances roughly 0.3 times the solar value, while the ejecta, with the exception of Fe, have relative abundances that are typical of Type Ia supernovae. The addition of another component of Fe emission, which we associate with ejecta, at a temperature at least two times higher and an ionization age $\\sim$ 100 times lower than the Si ejecta, does provide a good fit to the spectrum. This model is consistent with X-ray imaging results. Although fluorescent emission from dust in the remnant may contribute to the Fe K flux, we conclude that it is unlikely to dominate.

Una Hwang; John P. Hughes; Robert Petre

1997-12-17

209

Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. I: spectrum and chemical composition  

SciTech Connect

In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. In particular, at high energies we assume that D(E)?E{sup ?}, with ? = 1/3 and ? = 0.6 being the reference scenarios. The large scale distribution of supernova remnants in the Galaxy is modeled following the distribution of pulsars, with and without accounting for the spiral structure of the Galaxy. We find that the stochastic fluctuations induced by the spatial and temporal distribution of supernovae, together with the effect of spallation of nuclei, lead to mild but sensible violations of the simple, leaky-box-inspired rule that the spectrum observed at Earth is N(E)?E{sup ??} with ? = ?+?, where ? is the slope of the cosmic ray injection spectrum at the sources. Spallation of nuclei, even with the small rates appropriate for He, may account for small differences in spectral slopes between different nuclei, possibly providing an explanation for the recent CREAM observations. For ? = 1/3 we find that the slope of the proton and helium spectra are ? 2.67 and ? 2.6 respectively (with fluctuations depending on the realization of source distribution) at energies around ? 1 TeV (to be compared with the measured values of 2.660.02 and 2.580.02). For ? = 0.6 the hardening of the He spectra is not observed. The stochastic effects discussed above cannot be found in ordinary propagation calculations, such as GALPROP, where these effects and the point like nature of the sources are not taken into account. We also comment on the effect of time dependence of the escape of cosmic rays from supernova remnants, and of a possible clustering of the sources in superbubbles. In a second paper we will discuss the implications of these different scenarios for the anisotropy of cosmic rays.

Blasi, Pasquale; Amato, Elena, E-mail: blasi@arcetri.astro.it, E-mail: amato@arcetri.astro.it [INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5 50125 Firenze (Italy)

2012-01-01

210

Image of the Vela Supernova Remnant Taken by the High Energy Astronomy Observatory (HEAO)-2  

NASA Technical Reports Server (NTRS)

Like the Crab Nebula, the Vela Supernova Remnant has a radio pulsar at its center. In this image taken by the High Energy Astronomy Observatory (HEAO)-2/Einstein Observatory, the pulsar appears as a point source surrounded by weak and diffused emissions of x-rays. HEAO-2's computer processing system was able to record and display the total number of x-ray photons (a tiny bundle of radiant energy used as the fundamental unit of electromagnetic radiation) on a scale along the margin of the picture. The HEAO-2, the first imaging and largest x-ray telescope built to date, was capable of producing actual photographs of x-ray objects. Shortly after launch, the HEAO-2 was nicknamed the Einstein Observatory by its scientific experimenters in honor of the centernial of the birth of Albert Einstein, whose concepts of relativity and gravitation have influenced much of modern astrophysics, particularly x-ray astronomy. The HEAO-2, designed and developed by TRW, Inc. under the project management of the Marshall Space Flight Center, was launched aboard an Atlas/Centaur launch vehicle on November 13, 1978.

1980-01-01

211

Hubble Space Telescope Image, Supernova Remnant Cassiopeia A  

NASA Technical Reports Server (NTRS)

The colorful streamers that float across the sky in this photo taken by NASA's Hubble Space Telescope (HST) were created by the universe's biggest firecracker, the titanic supernova explosion of a massive star. The light from the exploding star reached Earth 320 years ago, nearly a century before the United States celebrated its birth with a bang. The dead star's shredded remains are called Cassiopeia A, or 'Cas A' for short. Cas A is the youngest known supernova remnant in our Milky Way Galaxy and resides 10,000 light-years away in the constellation Cassiopeia, so the star actually blew up 10,000 years before the light reached Earth in the late 1600s. This HST image of Cas A shows for the first time that the debris is arranged into thousands of small, cooling knots of gas. This material eventually will be recycled into building new generations of stars and planets. Our own Sun and planets are constructed from the debris of supernovae that exploded billions of years ago. This photo shows the upper rim of the super nova remnant's expanding shell. Near the top of the image are dozens of tiny clumps of matter. Each small clump, originally just a small fragment of the star, is tens of times larger than the diameter of our solar system. The colors highlight parts of the debris where chemical elements are glowing. The dark blue fragments, for example, are richest in oxygen; the red material is rich in sulfur. The images were taken with the Wide Field and Planetary Camera 2 in January 2000 and January 2002. Image Credit: NASA and HST team (Stoics/AURA). Acknowledgment: R. Fesen (Darmouth) and J. Morse ( Univ. of Colorado).

2000-01-01

212

The fate of supernova remnants near quiescent supermassive black holes  

NASA Astrophysics Data System (ADS)

There is mounting observational evidence that most galactic nuclei host both supermassive black holes (SMBHs) and young populations of stars. With an abundance of massive stars, core-collapse supernovae are expected in SMBH spheres of influence. We develop a novel numerical method, based on the Kompaneets approximation, to trace supernova remnant (SNR) evolution in these hostile environments, where radial gas gradients and SMBH tides are present. We trace the adiabatic evolution of the SNR shock until 50 per cent of the remnant is either in the radiative phase or is slowed down below the SMBH Keplerian velocity and is sheared apart. In this way, we obtain shapes and lifetimes of SNRs as a function of the explosion distance from the SMBH, the gas density profile and the SMBH mass. As an application, we focus here exclusively on quiescent SMBHs, because their light may not hamper detections of SNRs and because we can take advantage of the unsurpassed detailed observations of our Galactic Centre. Assuming that properties such as gas and stellar content scale appropriately with the SMBH mass, we study SNR evolution around other quiescent SMBHs. We find that, for SMBH masses over 107 M?, tidal disruption of SNRs can occur at less than 104 yr, leading to a shortened X-ray emitting adiabatic phase, and to no radiative phase. On the other hand, only modest disruption is expected in our Galactic Centre for SNRs in their X-ray stage. This is in accordance with estimates of the lifetime of the Sgr A East SNR, which leads us to expect one supernova per 104 yr in the sphere of influence of Sgr A*.

Rimoldi, A.; Rossi, E. M.; Piran, T.; Portegies Zwart, S.

2015-03-01

213

Supernovae. The bubble-like interior of the core-collapse supernova remnant Cassiopeia A.  

PubMed

The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnant's interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive (56)Ni-rich ejecta. If this is true, substantial amounts of its decay product, (56)Fe, may still reside in these interior cavities. PMID:25635094

Milisavljevic, Dan; Fesen, Robert A

2015-01-30

214

A NEW X-RAY VIEW OF THE SUPERNOVA REMNANT G272.2-3.2 AND ITS ENVIRONMENT  

SciTech Connect

We present an analysis of Chandra X-Ray Observatory data detailing a Galactic supernova remnant, G272.2-3.2. A clear shell of emission is resolved as a series of filaments and knots around the entire rim of the remnant. Spectral analysis of these features show that they are consistent with shock heating of interstellar material in a clumpy medium. We contrast these X-ray images with 22 {mu}m Wide-field Infrared Survey Explorer (WISE) data to verify this interaction. Spatially separated from the shell we see a central diffuse region dominated by harder, hotter emission. Spatial spectroscopy shows a clear enhancement of metals consistent with a Type Ia explosion, namely S, Si, and Fe. We find no clear evidence for a compact object or pulsar wind nebula and argue for a Type Ia origin. Consideration of the ionization timescales suggest an age of 11,000 yr for G272.2-3.2.

McEntaffer, R. L.; Grieves, N.; DeRoo, C.; Brantseg, T., E-mail: randall-mcentaffer@uiowa.edu [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States)

2013-09-10

215

A New X-Ray View of the Supernova Remnant G272.2-3.2 and Its Environment  

NASA Astrophysics Data System (ADS)

We present an analysis of Chandra X-Ray Observatory data detailing a Galactic supernova remnant, G272.2-3.2. A clear shell of emission is resolved as a series of filaments and knots around the entire rim of the remnant. Spectral analysis of these features show that they are consistent with shock heating of interstellar material in a clumpy medium. We contrast these X-ray images with 22 ?m Wide-field Infrared Survey Explorer (WISE) data to verify this interaction. Spatially separated from the shell we see a central diffuse region dominated by harder, hotter emission. Spatial spectroscopy shows a clear enhancement of metals consistent with a Type Ia explosion, namely S, Si, and Fe. We find no clear evidence for a compact object or pulsar wind nebula and argue for a Type Ia origin. Consideration of the ionization timescales suggest an age of 11,000 yr for G272.2-3.2.

McEntaffer, R. L.; Grieves, N.; DeRoo, C.; Brantseg, T.

2013-09-01

216

Nature Versus Nurture: Do Asymmetries in Supernova Remnant Ejecta Reflect the Explosion or the Environment of the Progenitor?  

NASA Astrophysics Data System (ADS)

Recent work has demonstrated that Type Ia supernova remnants (SNRs) have statistically more spherical and mirror-symmetric X-ray line and continuum emission than core-collapse (CC) SNRs. The ability to type SNRs based on thermal X-ray emission morphology alone could reflect either the distinct explosion mechanisms or the different circumstellar environments of Type Ia and CC SNRs. In this talk, we present new results exploring this "nature" versus "nurture" conundrum. To test if asymmetries arise from explosions, we examine whether pulsar kick velocities are correlated with ejecta (a)symmetries (as measured using Chandra, XMM-Newton, and ROSAT images). We also study Type Ia and CC SNRs in a variety of conditions to search for trends in (a)symmetries with environmental factors (e.g., star-formation activity). Collectively, this work provides new insights into the nature of SN explosions and the dynamical evolution of their remnants.

Lopez, Laura A.; Ramirez-Ruiz, E.

2011-09-01

217

Asymmetric Circumstellar Matter in Type Ia Supernova Remnants  

NASA Astrophysics Data System (ADS)

The progenitors of Type Ia supernovae (SNe) are not well understood, but are likely to be of diverse origin, including single- and double-degenerate binary systems. Among single-degenerate progenitors, substantial amounts of circumstellar material (CSM) are expelled prior to the SN explosions by asymptotic giant branch (AGB) companions to the accreting white dwarfs. A subsequent collision of SN ejecta with the dense AGB wind has been detected among several distant SNe such as SN 2002ic, SN 2008J, and more recently PTF11kx. Dense CSM ejected by an AGB companion is present in the remnant of Kepler's SN of 1604, a Type Ia event. Observations of distant SNe hint at strongly asymmetric CSM distributions. A recent study of the CSM in Kepler's SNR by Burkey et al. indicates a large (factor of 10) density contrast between the dense, disk-like equatorial outflow and the more tenuous AGB wind above the orbital plane. A significant fraction of mature Type Ia SNRs in the Large Magellanic Cloud (LMC) shows the presence of dense Fe-rich ejecta in their interiors that cannot be explained by standard models of Type Ia explosions in a uniform ambient interstellar medium. We explore the hypothesis that these remnants originated in Type Ia explosions with strongly asymmetric CSM distributions such as found in Kepler's SNR. We present results of 2-D hydrodynamical simulations of the interaction of SN ejecta with asymmetric, disk-like AGB winds throughout the whole adiabatic stage of SNR evolution. Dense, asymmetric, and highly-ionized Fe-rich ejecta are indeed present in the simulated remnants, while the blast wave assumes a spherical shape shortly after passage through the ambient CSM. We also present simulated X-ray images and spectra and compare them with X-ray observations of selected remnants in the LMC. These remnants include DEM L238 and L249, recently observed by Suzaku, whose X-ray emission is strongly dominated by dense Fe-rich ejecta in their interiors. We contrast these remnants to more typical mature Type Ia SNRs such as 0534-69.9 and 0548-70.4 whose Suzaku spectra can be satisfactorily modeled with standard (without any CSM) X-ray models for Type Ia SNRs.

Borkowski, Kazimierz J.; Reynolds, S. P.; Blondin, J. M.

2013-01-01

218

Second Epoch Hubble Space Telescope Imaging of Kepler's Supernova Remnant  

NASA Astrophysics Data System (ADS)

We have obtained new HST/WFC3 images of Kepler's supernova remnant in H-alpha (F656N) and [N II] (F658N) emission line filters. The bright radiative shocks in dense clumps are detected in both filters, while non-radiative shocks are seen as faint filaments only in the H-alpha image. Most of these Balmer filaments lie around the periphery of the remnant where the blast wave encounters partially neutral interstellar gas. We compare the new images with HST/ACS images taken nearly 10 years previously, and find that these filaments tracing the forward shock have moved 0.6"-0.9" between the two epochs. Assuming a distance of 4 kpc to the remnant, these proper motions correspond to shock velocities of 1160-1740 km/s, which are consistent with the published values, 1550-2000 km/s (e.g. Blair et al. 1991, ApJ 366, 484). We also find a few Balmer filaments with highly non-radial proper motions. In one particularly interesting case in the projected interior of the remnant, SE of the center, the shock appears to have wrapped around a sharp density enhancement and moved about 0.3" in the period between the observations.The images allow us to study the evolution of the shock around an ejecta knot, which is punching through the remnant boundary in the northwest. The forward shock, visible as an arcuate Balmer filament, has moved about 1". At the trailing edges, the system of radiative knots formed by Rayleigh-Taylor instabilities have undergone significant changes - some knots have disappeared, new ones have appeared, and many have changed in brightness. Elsewhere in the remnant we find changes in the relative intensities of many small, bright knots over the 10 year baseline, indicating the short radiative lifetimes of these features.This work has been supported in part by grant HST-GO-12885 to the Universities Space Research Association.

Sankrit, Ravi; Blair, William P.; Borkowski, Kazimierz J.; Long, Knox S.; Patnaude, Daniel; Raymond, John C.; Reynolds, Stephen P.; Williams, Brian J.

2015-01-01

219

SUPERNOVA REMNANT SNR 1987A IN THE MID-INFRARED AT 18 YEARS  

E-print Network

1 SUPERNOVA REMNANT SNR 1987A IN THE MID-INFRARED AT 18 YEARS Patrice Bouchet (1) -- Eli Dwek (2 be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly

De Buizer, James Michael

220

Spectral and Morphological Analysis of the Remnant of Supernova 1987A with ALMA and ATCA  

NASA Astrophysics Data System (ADS)

We present a comprehensive spectral and morphological analysis of the remnant of supernova (SN) 1987A with the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/submillimeter Array (ALMA). The non-thermal and thermal components of the radio emission are investigated in images from 94 to 672 GHz (? 3.2 mm to 450 ?m), with the assistance of a high-resolution 44 GHz synchrotron template from the ATCA, and a dust template from ALMA observations at 672 GHz. An analysis of the emission distribution over the equatorial ring in images from 44 to 345 GHz highlights a gradual decrease of the east-to-west asymmetry ratio with frequency. We attribute this to the shorter synchrotron lifetime at high frequencies. Across the transition from radio to far infrared, both the synchrotron/dust-subtracted images and the spectral energy distribution (SED) suggest additional emission beside the main synchrotron component (S ?vprop?-0.73) and the thermal component originating from dust grains at T ~ 22 K. This excess could be due to free-free flux or emission from grains of colder dust. However, a second flat-spectrum synchrotron component appears to better fit the SED, implying that the emission could be attributed to a pulsar wind nebula (PWN). The residual emission is mainly localized west of the SN site, as the spectral analysis yields -0.4 <~ ? <~ -0.1 across the western regions, with ? ~ 0 around the central region. If there is a PWN in the remnant interior, these data suggest that the pulsar may be offset westward from the SN position.

Zanardo, Giovanna; Staveley-Smith, Lister; Indebetouw, Remy; Chevalier, Roger A.; Matsuura, Mikako; Gaensler, Bryan M.; Barlow, Michael J.; Fransson, Claes; Manchester, Richard N.; Baes, Maarten; Kamenetzky, Julia R.; Laki?evi?, Maa; Lundqvist, Peter; Marcaide, Jon M.; Mart-Vidal, Ivan; Meixner, Margaret; Ng, C.-Y.; Park, Sangwook; Sonneborn, George; Spyromilio, Jason; van Loon, Jacco Th.

2014-12-01

221

NUMERICAL STUDY OF THE VISHNIAC INSTABILITY IN SUPERNOVA REMNANTS  

SciTech Connect

The Vishniac instability is thought to explain the complex structure of radiative supernova remnants in their Pressure-Driven Thin Shell (PDTS) phase after a blast wave (BW) has propagated from a central explosion. In this paper, the propagation of the BW and the evolution of the PDTS stage are studied numerically with the two-dimensional (2D) code HYDRO-MUSCL for a finite-thickness shell expanding in the interstellar medium (ISM). Special attention is paid to the adiabatic index, {gamma}, and three distinct values are taken for the cavity ({gamma}{sub 1}), the shell ({gamma}{sub 2}), and the ISM ({gamma}{sub 3}) with the condition {gamma}{sub 2} < {gamma}{sub 1}, {gamma}{sub 3}. This low value of {gamma}{sub 2} accounts for the high density in the shell achieved by a strong radiative cooling. Once the spherical background flow is obtained, the evolution of a 2D-axisymmetric perturbation is computed from the linear to the nonlinear regime. The overstable mechanism, previously demonstrated theoretically by E. T. Vishniac in 1983, is recovered numerically in the linear stage and is expected to produce and enhance anisotropies and clumps on the shock front, leading to the disruption of the shell in the nonlinear phase. The period of the increasing oscillations and the growth rate of the instability are derived from several points of view (the position of the perturbed shock front, mass fluxes along the shell, and density maps), and the most unstable mode differing from the value given by Vishniac is computed. In addition, the influence of several parameters (the Mach number, amplitude and wavelength of the perturbation, and adiabatic index) is examined and for wavelengths that are large enough compared to the shell thickness, the same conclusion arises: in the late stage of the evolution of the radiative supernova remnant, the instability is dampened and the angular initial deformation of the shock front is smoothed while the mass density becomes uniform with the angle. As a result, our model shows that the supernova remnant returns to a stable evolution and the Vishniac instability does not lead to the fragmentation of the shock as predicted by the theory.

Michaut, C.; Cavet, C.; Bouquet, S. E.; Roy, F.; Nguyen, H. C., E-mail: claire.michaut@obspm.fr [LUTH, Observatoire de Paris, CNRS, Universite Paris-Diderot, F-92190 Meudon (France)

2012-11-10

222

Expansion of the Optical Remnant from Tychos Supernova  

NASA Astrophysics Data System (ADS)

Tycho's supernova remnant (SNR) is the expanding remnant from SN 1572, the penultimate Galactic supernova to have been recorded by contemporary observers. Its optical light is almost exclusively faint hydrogen Balmer emission around the periphery of the SNR, produced where fast nonradiative shocks encounter partly neutral preshock interstellar material. A variety of filaments, presumably thin sheets oriented tangentially, surround about one-third of the radio/X-ray shell. We have used CCD images, taken from KPNO over seven epochs from 1986 to 2009, to give the first optical expansion measurement of Tycho's SNR of the CCD era. Thirty filaments were identified and measured; the majority of them are at or near the remnant's outer rim and have proper motions from 0.19?? 0.01?? yr-1 to 0.26?? 0.02?? yr-1. The associated expansion indices, defined as the ratio of the current expansion rate to the historical mean, range from 0.35 0.03 to 0.52 0.05. Our measurements are consistent with those from the classic study by Kamper & van den Bergh (1978, ApJ, 224, 851) for the same filaments, but the CCD measurements have higher precision, and we have measured several additional fainter filaments. For direct comparison with X-ray and radio measurements, we selected the subset of optical filaments lying exactly at the outer rim, as identified in Chandra and VLA images. Considering only these filaments, virtually all have expansion indices greater than 0.40, the Sedov value. In addition to the rim filaments, there are several seen in the interior (in projection) that have smaller proper motions; these may have been decelerated, and/or they could be directed non-tangentially. Our final epoch of images, taken from the 3.5m WIYN telescope in 2009, reveals previously undetected extremely faint optical emission surrounding well over half of the remnant shell. This newly detected faint emission agrees well with the limb as defined in X-ray and radio images.This work has been supported in part by NSF grant AST-098566.

Putko, Joseph; Winkler, P. Frank; Blair, William P.

2015-01-01

223

AZIMUTHAL DENSITY VARIATIONS AROUND THE RIM OF TYCHO's SUPERNOVA REMNANT  

SciTech Connect

Spitzer images of Tycho's supernova remnant in the mid-infrared reveal limb-brightened emission from the entire periphery of the shell and faint filamentary structures in the interior. As with other young remnants, this emission is produced by dust grains, warmed to {approx}100 K in the post-shock environment by collisions with energetic electrons and ions. The ratio of the 70 to 24 {mu}m fluxes is a diagnostic of the dust temperature, which in turn is a sensitive function of the plasma density. We find significant variations in the 70/24 flux ratio around the periphery of Tycho's forward shock, implying order-of-magnitude variations in density. While some of these are likely localized interactions with dense clumps of the interstellar medium (ISM), we find an overall gradient in the ambient density surrounding Tycho, with densities 3-10 times higher in the northeast than in the southwest. This large density gradient is qualitatively consistent with the variations in the proper motion of the shock observed in radio and X-ray studies. Overall, the mean ISM density around Tycho is quite low ({approx}0.1-0.2 cm{sup -3}), consistent with the lack of thermal X-ray emission observed at the forward shock. We perform two-dimensional hydrodynamic simulations of a Type Ia supernova expanding into a density gradient in the ISM, and find that the overall round shape of the remnant is still easily achievable, even for explosions into significant gradients. However, this leads to an offset of the center of the explosion from the geometric center of the remnant of up to 20%, although lower values of 10% are preferred. The best match with hydrodynamical simulations is achieved if Tycho is located at a large (3-4 kpc) distance in a medium with a mean preshock density of {approx}0.2 cm{sup -3}. Such preshock densities are obtained for highly ({approx}> 50%) porous ISM grains.

Williams, Brian J.; Hewitt, John W.; Petre, Robert [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Borkowski, Kazimierz J.; Alwin Mao, S.; Reynolds, Stephen P.; Blondin, John M. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Ghavamian, Parviz, E-mail: brian.j.williams@nasa.gov [Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States)

2013-06-20

224

Neutron stars, fast pulsars, supernovae and the equation of state of dense matter  

SciTech Connect

We discuss the prospects for obtaining constraints on the equation of state from astrophysical sources. Neutron star masses although few are known at present, provide a very direct constraint in as much as the connection to the equation of state involves only the assumption that Einstein's general theory of relativity is correct at the macroscopic scale. If the millisecond pulses briefly observed in the remnant of SN1987A can be attributed to uniform rotation of a pulsar, then a very severe constraint is placed on the equation of state. The theory again is very secure. The precise nature of the constraint is not yet understood, but it appears that the equation of state must be neither too soft nor stiff, and it may be that there is information not only on the stiffness of the equation of state but on its shape. Supernovae simulations involve such a plethora of physical processes including those involved in the evolution of the precollapse configuration, not all of them known or understood, that they provide no constraint at the present time. Not even the broad category of mechanism for the explosion is agreed upon (prompt shock, delayed shock, or nuclear explosion). In connection with very fast pulsars, we include some speculations on pure quark matter stars, and on possible scenarios for understanding the disappearance of the fast pulsar in SN1987A. 47 refs., 16 figs., 1 tab.

Glendening, N.K.

1989-06-01

225

Spitzer Space Telescope Spectroscopy of the Kepler Supernova Remnant  

NASA Technical Reports Server (NTRS)

The Infrared Spectrograph on the Spitzer Space Telescope was used for observations of the Kepler supernova remnant, with all four instrument modules targeted on the bright infrared knot located at 17h30m35.80s,-21d28m54.0s (J2000). The low spectral resolution modules data show a dust continuum spectrum consistent with dust grains heated by high-energy electrons, while the high resolution modules data show atomic emission line ratios consistent with excitation by a high velocity shock of greater than 100 kilometers per second and electron densities of approximately 1,000 per centimeter. The abundance ratios for the six detected elements show signs of heavy-element enhancement. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology. Support for this work was provided by NASA's Office of Space Science.

Roellig, T. L.; Onaka, T.

2004-01-01

226

Origin of Galactic Cosmic Rays from Supernova Remnants  

NASA Astrophysics Data System (ADS)

We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown that the measured primary and secondary CR nuclei energy spectra as well as the observed positron-to-electron ratio are consistent with the origin of GCRs up to the energy 1017 eV in SNRs. Existing SNR emission data provide evidences for efficient CR production in SNRs accompanied by significant magnetic field amplification. In some cases the nature of the detected ?-ray emission is difficult to determine because key SNR parameters are not known or poorly constrained.

Berezhko, E. G.

2014-11-01

227

Phosphorus in the young supernova remnant Cassiopeia A.  

PubMed

Phosphorus ((31)P), which is essential for life, is thought to be synthesized in massive stars and dispersed into interstellar space when these stars explode as supernovae (SNe). Here, we report on near-infrared spectroscopic observations of the young SN remnant Cassiopeia A, which show that the abundance ratio of phosphorus to the major nucleosynthetic product iron ((56)Fe) in SN material is up to 100 times the average ratio of the Milky Way, confirming that phosphorus is produced in SNe. The observed range is compatible with predictions from SN nucleosynthetic models but not with the scenario in which the chemical elements in the inner SN layers are completely mixed by hydrodynamic instabilities during the explosion. PMID:24337291

Koo, Bon-Chul; Lee, Yong-Hyun; Moon, Dae-Sik; Yoon, Sung-Chul; Raymond, John C

2013-12-13

228

High-Resolution Polarimetry of Supernova Remnant Kesteven 69  

NASA Astrophysics Data System (ADS)

Reported here are high-resolution 6 cm measurements of the adolescent supernova remnant (SNR) Kesteven 69 made with the hybrid BnC configuration of the Very Large Array. Several three-field mosaics of the polarized and total intensity have been used to study this SNR. These investigations lead to a coherent picture of this region. The expanding shock defines an outer rim of high total intensity, suggesting the front is running into large dense clouds with random magnetic field directions. The SNR consists of predominantly of two types of regions, those with high total and relatively weak polarized emission and those with relatively weak total and strong polarized emission. This morphology can be generally explained by the number of clouds with organized magnetic field along the line of sight. Within this SNR there are regions where the field is varying from radial to tangential. As the SN shock encounters clouds, magnetic fields within clouds will strongly affect cloud dynamics.

Wood, C. A.; Mufson, S. L.; Dickel, J. R.

2008-06-01

229

SN1987A: The Birth of a Supernova Remnant  

NASA Technical Reports Server (NTRS)

This grant was intended to support the development of theoretical models needed to interpret and understand the observations by the Hubble Space Telescope and the Chandra X-ray telescope of the rapidly developing remnant of Supernova 1987A. In addition, we carried out a few investigations of related topics. The project was spectacularly successful. The models that we developed provide the definitive framework for predicting and interpreting this phenomenon. Following is a list of publications based on our work. Some of these papers include results of both theoretical modeling supported by this project and also analysis of data supported by the Space Telescope Science Institute and the Chandra X-ray Observatory. We first list papers published in refereed journals, then conference proceedings and book chapters, and also an educational web site.

McCray, Richard

2003-01-01

230

Grain Destruction in a Supernova Remnant Shock Wave  

NASA Technical Reports Server (NTRS)

Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV (lambda)1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10'' behind the shock is too high compared to the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre- shock medium limit our ability to test dust destruction models in detail.

Raymond, John C.; Ghavamian, Parviz; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Gaetz, Terrance J.; Sankrit, Ravi

2014-01-01

231

Grain Survival in Supernova Remnants and Herbig-Haro Objects  

E-print Network

By using the flux ratio [FeII]8617/[OI]6300, we demonstrate that most of the interstellar dust grains survive in shocks associated with supernova remnants and Herbig-Haro objects. The [FeII]/[OI] flux ratio is sensitive to the gas-phase Fe/O abundance ratio, but is insensitive to the ionization state, temperature, and density of the gas. We calculate the [FeII]/[OI] flux ratio in shocks, and compare the results with the observational data. When only 20% of iron is in the gas phase, the models reproduce most successfully the observations. This finding is in conflict with the current consensus that shocks destroy almost all the grains and 100% of metals are in the gas phase. We comment on previous works on grain destruction, and discuss why grains are not destroyed in shocks.

H. Mouri; Y. Taniguchi

2000-03-13

232

Supernova Remnants in the Most Fertile Galaxy: NGC 6946  

NASA Astrophysics Data System (ADS)

As the host to more recorded supernovae (nine in the past century) than any other galaxy, ngal is a unique venue for studying young (and old) supernova remnants (SNRs). Using deep emission-line images of ngal we obtained from WIYN, we have identified 148 new emission nebulae through their high S II:H? ratios, indicating that they are strong SNR candidates. This is over 5 times as many as have previously been identified; yet of the 175 total objects, only 6 have been spectroscopically confirmed. We propose multislit spectroscopy from GMOS-N to study the majority of those with no spectra to date. Some 26 are essentially unresolved in our images (diameters ? 1 arcsec=27 pc at ngal) and hence probably are relatively young. Several are also coincident with soft X-ray sources (a further indicator of youthful vigor) and have strong O III emission. Some may be rare, ejecta- dominated core-collapse SNRs akin to Cas A, where ``fresh" nucleosynthesis products can be seen. Only spectroscopy, to look for broad emission lines from fast-moving ejecta, can confirm this. We will include spectra of two of the nine recorded SNe in ngal-the first late-time spectrum of SN 2004et, and the first of SN 1980K with high signal-to-noise-adding to the extremely small number of spectra for SNRs only a few decades old. Finally we will use the H II:H? ratio in a large number of ISM-dominated SNRs to map the N abundance and its gradient across the disk of ngal, and we will use archival HST images to identify the stellar environments that produced the SNe whose remnants we see today.

Winkler, P. Frank; Long, Knox S.; Blair, William P.

2014-08-01

233

G29.7-0.3: another supernova remnant with an identity crisis  

NASA Technical Reports Server (NTRS)

New radio and X-ray observations of the galactic supernova remnant G29.7-0.3 show that it is composed of two spectrally distinct components: a steep-spectrum, incomplete shell 3 arcmin in extent enclosing a flat-spectrum, X-ray emitting region 30 arcsec across. Thus, G29.7-0.3 joins the ranks of supernova remnants which exhibit a combination of Crab-like and shell remnant attributes. The Crab-like core has the highest ratio of X-ray radio luminosity of all the Crab-like remnants observed to date, suggesting that it is an extremely young object.

Becker, R. H.; Helfand, D. J.; Szymkowiak, A. E.

1983-01-01

234

ROSAT HRI observations of Magellanic Cloud supernova remnants  

NASA Technical Reports Server (NTRS)

Analysis of deep ROSAT high resolution imager (HRI) observations of two oxygen-rich supernova remnants (SNR's) in the Magellanic Clouds is described. For N132D, I exploit the limited spectral information provided by the HRI to investigate arcsecond scale spectral variations. I find that there is a region of harder X-ray emission near the southern limb and regions of softer emission near the center and northwestern limb. The remnant is believed to be interacting with a molecular cloud and the harder emission to the south is explained as a result of increased absorption along the line-of-sight there. I argue that the softer emission comes from X-ray emitting material with an enhanced abundance of oxygen. For the second SNR, E0102.2 72.2, the spatial structure is investigated in detail using two-dimensional image fitting techniques. Evidence is found for a ring-like and a spherically symmetric shell-like component both of which were modeled as homogeneous regions. In addition, a significant fraction of the observed flux (approximately 11 percent) must come from a resolved clumped component. A comparison with optical and radio imagery is made to provide a physical basis for the components identified in the X-ray analysis. The mass of X-ray emitting gas in the remnant is estimated and a value of approximately 75 M(solar mass) was determined. The dominant uncertainty on this quantity is the extent of unresolved clumping in the X-ray gas. Such clumping would tend to reduce the mass estimate by f(exp 1/2), where f is the mean volume filling factor of the gas.

Hughes, John P.

1994-01-01

235

IS THERE A HIDDEN HOLE IN TYPE Ia SUPERNOVA REMNANTS?  

SciTech Connect

In this paper, we report on the bulk features of the hole carved by the companion star in the material ejected during a Type Ia supernova (SN Ia) explosion. In particular we are interested in the long-term evolution of the hole as well as in its fingerprint in the geometry of the supernova remnant (SNR) after several centuries of evolution, which is a hot topic in current SN Ia studies. We use an axisymmetric smoothed particle hydrodynamics code to characterize the geometric properties of the SNR resulting from the interaction of this ejected material with the ambient medium. Our aim is to use SNR observations to constrain the single degenerate scenario for SN Ia progenitors. Our simulations show that the hole will remain open during centuries, although its partial or total closure at later times due to hydrodynamic instabilities is not excluded. Close to the edge of the hole, the Rayleigh-Taylor instability grows faster, leading to plumes that approach the edge of the forward shock. We also discuss other geometrical properties of the simulations, like the evolution of the contact discontinuity.

Garcia-Senz, D. [Departament de Fisica i Enginyeria Nuclear, UPC, Compte d'Urgell 187, 08036 Barcelona (Spain); Badenes, C. [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Serichol, N., E-mail: domingo.garcia@upc.edu, E-mail: carles@astro.tau.ac.il, E-mail: nuria.serichol@upc.edu [Departament de Matematica Aplicada III, Sor Eulalia d'Anzizu, 08034 Barcelona (Spain)

2012-01-20

236

Fermi Proves Supernova Remnants Make Cosmic Rays - Duration: 3:40.  

NASA Video Gallery

The husks of exploded stars produce some of the fastest particles in the cosmos. New findings by NASA's Fermi show that two supernova remnants accelerate protons to near the speed of light. The pro...

237

UNRAVELING THE ORIGIN OF OVERIONIZED PLASMA IN THE GALACTIC SUPERNOVA REMNANT W49B  

E-print Network

Recent observations have shown several supernova remnants (SNRs) have overionized plasmas, where ions are stripped of more electrons than they would be if in equilibrium with the electron temperature. Rapid electron cooling ...

Lopez, Laura A.

238

CAVITY OF MOLECULAR GAS ASSOCIATED WITH SUPERNOVA REMNANT 3C 397  

E-print Network

3C 397 is a radio and X-ray bright Galactic supernova remnant (SNR) with an unusual rectangular morphology. Our CO observation obtained with the Purple Mountain Observatory at Delingha, Qinghai Province, China reveals that ...

Jiang, Bing

239

Distribution of novae and supernova remnants in the Large Magellanic Cloud  

SciTech Connect

Novae in the LMC appear to be distributred like an old disk population. The fact that no concentration of novae is seen within the Bar of the Large Cloud suggests that this feature is of relatively recent origin. Supernova remnants are seen to exhibit concentrations in the 30 Dor region, in the Bar of the Large Cloud, and in Constellation III. This distribution supports the idea that most of the supernova remnants in the LMC had young massive progenitors. 11 references.

Van den Bergh, S.

1988-12-01

240

DUST IN A TYPE Ia SUPERNOVA PROGENITOR: SPITZER SPECTROSCOPY OF KEPLER'S SUPERNOVA REMNANT  

SciTech Connect

Characterization of the relatively poorly understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's supernova remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 {mu}m infrared (IR) spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 {mu}m, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the asymptotic giant branch stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength Infrared Spectrograph and Infrared Array Camera data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally heated dust emission from fast shocks (>1000 km s{sup -1}) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are {approx}80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km s{sup -1}) into moderate density material (n{sub 0} {approx} 50-250 cm{sup -3}) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

Williams, Brian J.; Borkowski, Kazimierz J.; Reynolds, Stephen P. [Physics Department, North Carolina State University, Raleigh, NC 27695-8202 (United States); Ghavamian, Parviz [Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Long, Knox S. [STScI, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Sankrit, Ravi, E-mail: brian.j.williams@nasa.gov [SOFIA/USRA, NASA Ames Research Center, M/S N211-3, Moffett Field, CA 94035 (United States)

2012-08-10

241

Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant  

NASA Technical Reports Server (NTRS)

Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally-heated dust emission from fast shocks (> 1000 km/s) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

Williams, Brian J.; Borkowski, Kazimierz; Reynolds, Stephen P.; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sankrit, Ravi

2012-01-01

242

SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD  

E-print Network

The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and ?-ray observations of this object, ...

Gelfand, Joseph D.

243

Studying Young and Old Supernova Remnants with the Upcoming ASTRO-H X-ray Mission  

NASA Astrophysics Data System (ADS)

The upcoming X-ray mission ASTRO-H will open a new discovery window to the high-energy Universe thanks to the unprecedented high-resolution spectroscopy (~7eV) to be achieved with the Soft X-ray Spectrometer (SXS) combined with its broadband coverage (0.5-600 keV) with the Soft X-ray Imager (SXI), Hard X-ray Imager (HXI) and the Soft Gamma-ray Detector (SGD). Supernova remnants (SNRs) are a prime science focus for ASTRO-H, particularly with the SXS providing accurate plasma diagnostics of line-rich spectra expected from the youngest, ejecta-dominated, SNRs to the oldest SNRs impacted by their interaction with the Interstellar Medium (ISM). We here highlight the SNR science topics and program that the ASTRO-H team considers of highest priority and impact. For the younger SNRs, the primary science goals are (1) using abundance measurements to unveil SNR progenitors, (2) using spatial and velocity distribution of the ejecta to understand supernova explosion mechanisms, and (3) revealing the link between the thermal plasma state of SNRs and the efficiency of their particle acceleration. For the older SNRs where thermal emission is dominated or heavily impacted by the ISM, the primary goals are (1) constraining metal abundances and physical processes in the mature limb-brightened SNRs, and (2) understanding the puzzling nature of the `mixed-morphology' SNRs and the physics of recombining plasma. For the pulsar-powered nebulae, also known as Pulsar Wind Nebulae (PWNe) or plerions with many still lacking thermal X-ray emission from their supernova shells, ASTRO-H will shed light on their progenitors and environment. The hard X-ray coverage on board ASTRO-H will further allow a study of their broadband spectra (for the brightest objects), beyond NuSTAR's range, filling the gap between the soft X-ray regime (with current X-ray missions) and the gamma-ray regime (with Fermi in the GeV and H.E.S.S. in the TeV), allowing the search for spectral breaks in the hard X-ray band.

Safi-Harb, Samar; Hughes, John P.; Long, Knox; Bamba, Aya; Aharonian, Felix; Foster, Adam; Funk, Stefan; Hiraga, Junko; Ishida, Manabu; Katsuda, Satoru; Koyama, Katsuji; Leutenegger, Maurice; Maeda, Yoshitomo; Matsumoto, Hironori; Mori, Koji; Nakajima, Hiroshi; Nakamori, Takashi; Nobukawa, Masayoshi; Ozaki, Masanobu; Petre, Robert; Sawada, Makoto; Tamagawa, Toru; Tamura, Keisuke; Tanaka, Takaaki; Tomida, Hiroshi; Tsunemi, Hiroshi; Uchida, Hiroyuki; Uno, Shin'ichiro; Uchiyama, Yasunobu; Yamaguchi, Hiroya; Yamauchi, Shigeo; ASTRO-H Science Working Group

2015-01-01

244

ALEXIS Observations of the Monogem Ring Supernova Remnant  

NASA Technical Reports Server (NTRS)

The subject grant is for the analysis of ALEXIS observations of the Monogem Ring supernova remnant using the diffuse all-sky maps produced from the ALEXIS all-sky survey. The work is to produce ratio maps of the three energy bands provided by ALEXIS, analyze the ratio data to constrain the intervening neutral hydrogen column density and the temperature and elemental abundances of the X-ray emitting gas, compare the structure to that observed in the ROSAT maps, and incorporate the results into current supenova remnant evolution models. The work outlined above has been significantly delayed since the ALEXIS diffuse all-sky maps took longer to produce than anticipated. Unfortunately, the ALEXIS satellite suffered a failure of the Pegasus launch vehicle which left the satellite in a partially functioning condition. The attitude control system of the spacecraft was unable to operate as planned and this has greatly increased the complexity of the aspect solution. Our colleagues at Los Alamos have made progress in producing these maps and are nearing completion of the final maps. However, the quality of the data have been significantly compromised by the overall lower exposure due to the spacecraft problems and the higher background of the micro-channel plate detectors. We have compared the ALEXIS and ROSAT maps of this region of the sky and there is no obvious signal in the ALEXIS maps of the Monogem Ring. We are now exploring correlation techniques to determine if there is indeed a faint signal in the ALEXIS maps. Although, the project has been a disappointment so far, the data may still provide a valuable lower limit on the neutral hydrogen column density. This is a far cry from our original intentions, but would still be valuable science. Given the large delays in producing the ALEXIS sky maps, this work will continue past the end of the grant period.

Plucinsky, Paul; West, Donald (Technical Monitor)

2001-01-01

245

Supernova Remnant W49B and Its Environment  

NASA Astrophysics Data System (ADS)

We study gamma-ray supernova remnant (SNR) W49B and its environment using recent radio and infrared data. Spitzer Infrared Spectrograph low resolution data of W49B shows shocked excitation lines of H2 (0,0) S(0)-S(7) from the SNR-molecular cloud interaction. The H2 gas is composed of two components with temperatures of ~260 K and ~1060 K, respectively. Various spectral lines from atomic and ionic particles are detected toward W49B. We suggest that the ionic phase has an electron density of ~500 cm-3 and a temperature of ~104 K by the spectral line diagnoses. The mid- and far-infrared data from MSX, Spitzer, and Herschel reveal a 151 20 K hot dust component with a mass of 7.5 6.6 10-4 M ? and a 45 4 K warm dust component with a mass of 6.4 3.2 M ?. The hot dust is likely from materials swept up by the shock of W49B. The warm dust may possibly originate from the evaporation of clouds interacting with W49B. We build the H I absorption spectra of W49B and four nearby H II regions (W49A, G42.90+0.58, G42.43-0.26, and G43.19-0.53) and study the relation between W49B and the surrounding molecular clouds by employing the 2.12 ?m infrared and CO data. We therefore obtain a kinematic distance of ~10 kpc for W49B and suggest that the remnant is likely associated with the CO cloud at about 40 km s-1.

Zhu, H.; Tian, W. W.; Zuo, P.

2014-10-01

246

Interstellar and Ejecta Dust in the Cas A Supernova Remnant  

NASA Technical Reports Server (NTRS)

The ejecta of the Cas A supernova remnant has a complex morphology, consisting of dense fast-moving line emitting knots and diffuse X-ray emitting regions that have encountered the reverse shock, as well as more slowly expanding, unshocked regions of the ejecta. Using the Spitzer 5-35 micron IRS data cube, and Herschel 70, 100, and 160 micron PACS data, we decompose the infrared emission from the remnant into distinct spectral components associated with the different regions of the ejecta. Such decomposition allows the association of different dust species with ejecta layers that underwent distinct nuclear burning histories, and determination of the dust heating mechanisms. Our decomposition identified three characteristic dust spectra. The first, most luminous one, exhibits strong emission features at approx. 9 and 21 micron, and a weaker 12 micron feature, and is closely associated with the ejecta knots that have strong [Ar II] 6.99 micron and [Ar III] 8.99 micron emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low MgO-to-SiO2 ratios. A second, very different dust spectrum that has no indication of any silicate features, is best fit by Al2O3 dust and is found in association with ejecta having strong [Ne II] 12.8 micron and [Ne III] 15.6 micron emission lines. A third characteristic dust spectrum shows features that best matched by magnesium silicates with relatively high MgO-to-SiO2 ratio. This dust is primarily associated with the X-ray emitting shocked ejecta and the shocked interstellar/circumstellar material. All three spectral components include an additional featureless cold dust component of unknown composition. Colder dust of indeterminate composition is associated with [Si II] 34.8 micron emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. The dust mass giving rise to the warm dust component is about approx. 0.1solar M. However, most of the dust mass is associated with the unidentified cold dust component. Its mass could be anywhere between 0.1 and 1 solar M, and is primarily limited by the mass of refractory elements in the ejecta. Given the large uncertainty in the dust mass, the question of whether supernovae can produce enough dust to account for ISM dust masses in the local and high-z universe remains largely unresolved.

Arendt, Richard G.; Dwek, Eli; Kober, Gladys; Rho, Jonghee; Hwang, Una

2013-01-01

247

A Search for Ultra--High-Energy Gamma-Ray Emission from Five Supernova Remnants  

NASA Astrophysics Data System (ADS)

The majority of the cosmic rays in our Galaxy with energies in the range of ~1010--1014 eV are thought to be accelerated in supernova remnants (SNRs). Measurements of SNR gamma-ray spectra in this energy region could support or contradict this concept. The Energetic Gamma-Ray Experiment Telescope (EGRET) collaboration has reported six sources of gamma rays above 108 eV whose coordinates are coincident with SNRs. Five of these sources are within the field of view of the CYGNUS extensive air shower detector. A search of the CYGNUS data set reveals no evidence of gamma-ray emission at energies ~1014 eV for these five SNRs. The flux upper limits from the CYGNUS data are compared to the lower energy fluxes measured with the EGRET detector using Drury, Aharonian, & Volk's recent model of gamma-ray production in the shocks of SNRs. The results suggest one or more of the following: (1) the gamma-ray spectra for these five SNRs soften by about 1014 eV, (2) the integral gamma-ray spectra of the SNRs are steeper than about E-1.3, or (3) most of the gamma rays detected with the EGRET instrument for each SNR are not produced in the SNR's shock but are produced at some other site (such as a pulsar).

Allen, G. E.; Berley, D.; Biller, S.; Burman, R. L.; Cavalli-Sforza, M.; Chang, C. Y.; Chen, M. L.; Chumney, P.; Coyne, D.; Dion, C. L.; Dorfan, D.; Ellsworth, R. W.; Goodman, J. A.; Haines, T. J.; Hoffman, C. M.; Kelley, L.; Klein, S.; Schmidt, D. M.; Schnee, R.; Shoup, A.; Sinnis, C.; Stark, M. J.; Williams, D. A.; Wu, J.-P.; Yang, T.; Yodh, G. B.

1995-07-01

248

ASCA Observations of the Composite Supernova Remnant G29.7-0.3  

NASA Astrophysics Data System (ADS)

We confirm the composite nature of the supernova remnant (SNR) G29.7-0.3 (Kes 75) using observations in the 0.5-8 keV energy range obtained with the ASCA X-ray observatory. Spatial and spectral analyses of the data show that G29.7 -0.3 is composed of a hard X-ray, nonthermal central source and a soft X-ray, thermal shell. Combining the results of our analysis with radio determinations of the distance to G29.7 -0.3 and its shell diameter (Becker & Helfand), we estimate the luminosities of the- two components of the SNR as well as its total mass and age. The Crab-like core has an X-ray luminosity of LX ? 1 x 1036 ergs s-1, making it the second most luminous synchrotron nebula in the Galaxy. The thermal X-ray emission of the shell supports an age estimate comparable to that of the Crab, and the shell's inferred composition and mass are consistent with a massive progenitor. An estimate of the current energy loss rate of the unseen pulsar from the synchrotron nebula's X-ray luminosity, coupled with a calculation of the total energy in nebular particles and fields from the shape of the radio-to-X-ray spectrum, also gives an age estimate of ?1O3 yr.

Blanton, Elizabeth L.; Helfand, David J.

1996-10-01

249

Spectrum of cosmic rays, produced in supernova remnants  

E-print Network

Nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants is employed to calculate CR spectra. The magnetic field in SNRs is assumed to be significantly amplified by the efficiently accelerating nuclear CR component. It is shown that the calculated CR spectra agree in a satisfactory way with the existing measurements up to the energy $10^{17}$ eV. The power law spectrum of protons extends up to the energy $3\\times 10^{15}$ eV with a subsequent exponential cutoff. It gives a natural explanation for the observed knee in the Galactic CR spectrum. The maximum energy of the accelerated nuclei is proportional to their charge number $Z$. Therefore the break in the Galactic CR spectrum is the result of the contribution of progressively heavier species in the overall CR spectrum so that at $10^{17}$ eV the CR spectrum is dominated by iron group nuclei. It is shown that this component plus a suitably chosen extragalactic CR component can give a consistent description for the entire Galactic CR spectrum.

E. G. Berezhko; H. J. Voelk

2007-04-13

250

HST/ACS Narrowband Imaging of the Kepler Supernova Remnant  

NASA Technical Reports Server (NTRS)

We present narrowband images of the Kepler supernova remnant obtained with the Advanced Camera for Surveys aboard the Hubble Space Telescope. The images, with an angular resolution of 0.05" reveal the structure of the emitting gas in unprecedented detail. Radiative and nonradiative shocks are found in close proximity, unresolvable in gromd-based spectra, indicating that the pre-shock medium is highly clumped. The ionization structure, traced by differences in the [0 111] to [N 11] flux ratio, varies on subarcsecond scales. The variation is due to 110th differences in shock velocity as well as gradients in the evolutionary stage of the shocks. A prollinent complex of knots protruding beyond the boundary of the rennallt in the northwest is found to consist of bright radiative knots, collected by arcuate nonradiative filaments. Based on the coincidence of the optical emission with a bright isolated knot of X-ray emission, we infer that this feature is due to a Rayleigh-Taylor finger that formed at the contact discontinuity and overtook the primary blast wave.

Sankrit, Ravi; Blair, William P.; Frattare, Lisa M.; Rudnick, Lawrence; DeLaney, Tracey; Harrus, Ilana M.; Ennis, Jessica A.

2007-01-01

251

IUE observations of oxygen-rich supernova remnants  

NASA Technical Reports Server (NTRS)

The IUE observations were used to determine the composition of the ejecta (especially C and Si abundances) and to test models for the ionization and excitation of the ejecta of two oxygen-rich supernova remnants (N132D in the Large Magellanic Cloud and 1E 0102-7219 in the Small Magellanic Cloud). Time-dependent photoionization by the EUV and X-ray radiation from 1E 0102-7219 can qualitatively explain its UV and optical line emission, but the density and ionization structures are complex and prevent a unique model from being specified. Many model parameters are poorly constrained, including the time dependence and shape of the ionizing spectrum. Moreover, the models presented are not self-consistent in that the volumes and densities of the optically emitting gas imply optical depths of order unity in the EUV, but absorption of the ionizing radiation was ignored. It is possible that these shortcomings reflect a more fundamental limitation of the model assumptions. It is assumed that the electron velocity distribution is Maxwellian and that the energy deposited by photoionization heats the electrons directly. The 500 eV electrons produced by the Auger process may excite or ionize other ions before they slow down enough to share their energy with other electrons. Many of the excitations would produce photons that could ionize lower ionization stages.

Blair, W. P.; Raymond, J. C.; Danziger, J.; Matteucci, F.

1988-01-01

252

SLOW DIFFUSION OF COSMIC RAYS AROUND A SUPERNOVA REMNANT  

SciTech Connect

We study the escape of cosmic-ray protons accelerated at a supernova remnant (SNR). We are interested in their propagation in the interstellar medium (ISM) after they leave the shock neighborhood where they are accelerated, but when they are still near the SNR with their energy density higher than that in the average ISM. Using Monte Carlo simulations, we found that the cosmic rays with energies of {approx}< TeV excite Alfven waves around the SNR on a scale of the SNR itself if the ISM is highly ionized. Thus, even if the cosmic rays can leave the shock, scattering by the waves prevents them from moving further away from the SNR. The cosmic rays form a slowly expanding cosmic-ray bubble, and they spend a long time around the SNR. This means that the cosmic rays cannot actually escape from the SNR until a fairly late stage of the SNR evolution. This is consistent with some results of Fermi and H.E.S.S. observations.

Fujita, Yutaka; Ohira, Yutaka; Takahara, Fumio [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)

2010-04-01

253

Non-thermal emission from old supernova remnants  

E-print Network

We study the non-thermal emission from old shell-type supernova remnants (SNRs) on the frame of a time-dependent model. In this model, the time-dependent non-thermal spectra of both primary electrons and protons as well as secondary electron/positron ($e^{\\pm}$) pairs can be calculated numerically by taking into account the evolution of the secondary $e^{\\pm}$ pairs produced from proton-proton (p-p) interactions due to the accelerated protons collide with the ambient matter in an SNR. The multi-wavelength photon spectrum for a given SNR can be produced through leptonic processes such as electron/positron synchrotron radiation, bremsstrahlung and inverse Compton scattering as well as hadronic interaction. Our results indicate that the non-thermal emission of the secondary $e^{\\pm}$ pairs is becoming more and more prominent when the SNR ages in the radiative phase because the source of the primary electrons has been cut off and the electron synchrotron energy loss is significant for a radiative SNR, whereas the secondary $e^{\\pm}$ pairs can be produced continuously for a long time in the phase due to the large energy loss time for the p-p interaction. We apply the model to two old SNRs, G8.7$-$0.1 and G23.3$-$0.3, and the predicted results can explain the observed multi-wavelength photon spectra for the two sources.

Jun Fang; Li Zhang

2007-11-27

254

Cosmic Ray Acceleration at Perpendicular Shocks in Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) are believed to accelerate particles up to high energies through the mechanism of diffusive shock acceleration (DSA). Except for direct plasma simulations, all modeling efforts must rely on a given form of the diffusion coefficient, a key parameter that embodies the interactions of energetic charged particles with magnetic turbulence. The so-called Bohm limit is commonly employed. In this paper, we revisit the question of acceleration at perpendicular shocks, by employing a realistic model of perpendicular diffusion. Our coefficient reduces to a power law in momentum for low momenta (of index ?), but becomes independent of the particle momentum at high momenta (reaching a constant value ?? above some characteristic momentum p c). We first provide simple analytical expressions of the maximum momentum that can be reached at a given time with this coefficient. Then we perform time-dependent numerical simulations to investigate the shape of the particle distribution that can be obtained when the particle pressure back-reacts on the flow. We observe that for a given index ? and injection level, the shock modifications are similar for different possible values of p c, whereas the particle spectra differ markedly. Of particular interest, low values of p c tend to remove the concavity once thought to be typical of non-linear DSA, and result in steep spectra, as required by recent high-energy observations of Galactic SNRs.

Ferrand, Gilles; Danos, Rebecca J.; Shalchi, Andreas; Safi-Harb, Samar; Edmon, Paul; Mendygral, Peter

2014-09-01

255

Fermi LAT observation of supernova remnant HB9  

NASA Astrophysics Data System (ADS)

A 5.5-yr Fermi LAT gamma-ray observation shows significant extended emission at the position of the supernova remnant HB9 (G160.9+2.6). The significance of the detection above the background for photon energies above 0.2 GeV is 16?. The gamma-ray flux above 0.2 GeV is (2.23 0.19stat) 10-8 photons cm-2 s-1, and the corresponding luminosity above 1 GeV is 1.4 1033 erg s-1 (for a source distance of 1 kpc). The spectrum of the source is best described by curved power law (log-parabola, dN/dE=N_0 E^{-(? +? log(E/1 GeV))} with ? = (2.24 0.09stat) and ? = 0.4 0.1stat)). The gamma-ray spectrum of the source is consistent with both leptonic and hadronic models, and the relevant physical parameters in each case are derived. More studies on the ambient density in the region of HB9 should be carried out to rule out or confirm hadronic and non-thermal bremsstrahlung scenarios for the gamma-ray emission.

Araya, Miguel

2014-10-01

256

The Likely Fermi Detection of the Supernova Remnant RCW 103  

NASA Astrophysics Data System (ADS)

We report on the results from our ?-ray analysis of the supernova remnant (SNR) RCW 103 region. The data were taken with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. An extended source is found at a position consistent with that of RCW 103 and its emission was only detected above 1 GeV (10? significance), with a power-law spectrum with a photon index of 2.0 0.1. We obtain its 1-300 GeV spectrum and the total flux gives a luminosity of 8.3 1033 erg s-1 at a source distance of 3.3 kpc. Given the positional coincidence and property similarities of this source with other SNRs, we identify it as the likely Fermi ?-ray counterpart to RCW 103. Including radio measurements of RCW 103, the spectral energy distribution (SED) is modeled by considering emission mechanisms based on both hadronic and leptonic scenarios. We find that models in the two scenarios can reproduce the observed SED, while in the hadronic scenario the existence of SNR-molecular cloud interactions is suggested as a high density of the target protons is required.

Xing, Yi; Wang, Zhongxiang; Zhang, Xiao; Chen, Yang

2014-02-01

257

Using optical lines to study particle acceleration at supernova remnants  

NASA Astrophysics Data System (ADS)

The shocks of several young supernova remnants (SNR) are often associated with very thin optical filaments dominated by Balmer emission resulting from charge-exchange and collisional excitation between neutral Hydrogen from the interstellar medium and shocked protons and electrons. Optical lines are a direct probe of the conditions at the shock, in particular the width of the narrow and broad components reflect the temperature upstream and downstream of the shock, respectively. When the shock accelerate efficiently non-thermal particles, the shock structure changes producing anomalous Balmer lines and it is possible to use their line shape and their spatial profile to check the efficiency of SNR shocks in accelerating cosmic rays. Here we illustrate the kinetic theory of shock acceleration in presence of neutrals with some applications to young SNRs. We show that in three cases (RCW 86, SNR 0509-67.5 and Tycho) anomalous Balmer lines can be explained assuming that a fraction of ? 10% of the total shock kinetic energy is converted into not thermal particles, while in one single case, the northwestern part of SN 1006, there is no evidence of efficient acceleration.

Morlino, Giovanni

2014-11-01

258

Supernova remnants as cosmic ray accelerators. SNR IC 443  

E-print Network

We examine the hypothesis that some supernova remnants (SNRs) may be responsible for some unidentified gamma-ray sources detected by EGRET instrument aboard the Compton Gamma Ray Observatory. If this is the case, gamma-rays are produced via pion production and decay from direct inelastic collisions of accelerated by SNR shock wave ultrarelativistic protons with target protons of the interstellar medium. We develop a 3-D hydrodynamical model of SNR IC 443 as a possible cosmic gamma-ray source 2EG J0618+2234. The derived parameters of IC 443: the explosion energy E_o=2.7*10^{50} erg, the initial hydrogen number density n(0)=0.21 cm^{-3}, the mean radius R=9.6 pc and the age t=4500 yr result in too low gamma-ray flux, mainly because of the low explosion energy. Therefore, we investigate in detail the hydrodynamics of IC 443 interaction with a nearby massive molecular cloud and show that the reverse shock wave considerably increases the cosmic ray density in the interaction region. Meantime, the Rayleigh-Taylor instability of contact discontinuity between the SNR and the cloud provides an effective mixing of the containing cosmic ray plasma and the cloud material. We show that the resulting gamma-ray flux is consistent with the observational data.

B. Hnatyk; O. Petruk

1999-02-10

259

SUPERNOVA REMNANT KES 17: AN EFFICIENT COSMIC RAY ACCELERATOR INSIDE A MOLECULAR CLOUD  

SciTech Connect

The supernova remnant Kes 17 (SNR G304.6+0.1) is one of a few but growing number of remnants detected across the electromagnetic spectrum. In this paper, we analyze recent radio, X-ray, and ?-ray observations of this object, determining that efficient cosmic ray acceleration is required to explain its broadband non-thermal spectrum. These observations also suggest that Kes 17 is expanding inside a molecular cloud, though our determination of its age depends on whether thermal conduction or clump evaporation is primarily responsible for its center-filled thermal X-ray morphology. Evidence for efficient cosmic ray acceleration in Kes 17 supports recent theoretical work concluding that the strong magnetic field, turbulence, and clumpy nature of molecular clouds enhance cosmic ray production in supernova remnants. While additional observations are needed to confirm this interpretation, further study of Kes 17 is important for understanding how cosmic rays are accelerated in supernova remnants.

Gelfand, Joseph D. [NYU Abu Dhabi, P.O. Box 903, New York, NY 10276 (United States); Castro, Daniel [MIT Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue 37-241, Cambridge, MA 02139 (United States); Slane, Patrick O. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Temim, Tea [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hughes, John P. [Department of Physics and Astronomy Rutgers University 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Rakowski, Cara, E-mail: jg168@cosmo.nyu.edu, E-mail: cara.rakowski@gmail.com [United States Patent and Trademark Office, 600 Dulany Street, Alexandria, VA (United States)

2013-11-10

260

SPIN TILTS IN THE DOUBLE PULSAR REVEAL SUPERNOVA SPIN ANGULAR-MOMENTUM PRODUCTION  

SciTech Connect

The system PSR J0737-3039 is the only binary pulsar known to consist of two radio pulsars (PSR J0737-3039 A and PSR J0737-3039 B). This unique configuration allows measurements of spin orientation for both pulsars: pulsar A's spin is tilted from the orbital angular momentum by no more than 14 deg at 95% confidence; pulsar B's by 130 {+-} 1 deg at 99.7% confidence. This spin-spin misalignment requires that the origin of most of B's present-day spin is connected to the supernova that formed pulsar B. Under the simplified assumption of a single, instantaneous kick during the supernova, the spin could be thought of as originating from the off-center nature of the kick, causing pulsar B to tumble to its misaligned state. With this assumption, and using current constraints on the kick magnitude, we find that pulsar B's instantaneous kick must have been displaced from the center of mass of the exploding star by at least 1 km and probably 5-10 km. Regardless of the details of the kick mechanism and the process that produced pulsar B's current spin, the measured spin-spin misalignment in the double pulsar system provides an empirical, direct constraint on the angular momentum production in this supernova. This constraint can be used to guide core-collapse simulations and the quest for understanding the spins and kicks of compact objects.

Farr, Will M.; Kremer, Kyle; Kalogera, Vassiliki [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Lyutikov, Maxim, E-mail: w-farr@northwestern.edu, E-mail: kylekremer2012@u.northwestern.edu, E-mail: vicky@northwestern.edu, E-mail: lyutikov@purdue.edu [Physics Department, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

2011-12-01

261

Supernova Remnants As Laboratories For Determining The Properties Of Ejecta Dust And The Processing Of Dust Grains In Shocks  

NASA Astrophysics Data System (ADS)

Recent infrared satellites, such as the Spitzer, Herschel, and WISE, have obtained a wealth of spectral and broadband data on the infrared (IR) emission from dust in supernova remnants (SNRs). Supernovae (SNe) are important producers of newly condensed dust during the early free-expansion phase of their evolution, and the dominant destroyers of dust during the subsequent remnant phase of their evolution. The infrared observations hold the key for determining their role in the origin and evolution of dust in the universe. We propose to model the composition, abundance, and size distribution of the dust in select Galactic and Magellanic Cloud remnants. As explained in detail below, the remnants were selected for the availability of IR and X-ray observations. All selected remnants have Spitzer IRS spectral data in the 5-35 ?m regions which allow us to determine the effect of grain processing in the shock. Some have spectral maps that allow the distinction between the IR emission from SN-condensed and swept up circumstellar and interstellar dust. All remnants have also been covered by Spitzer, Herschel, and WISE imaging, and have existing X-ray Chandra and/or XMM observations. The dust in some remnants is radiatively-heated by a pulsar wind nebula, and in others collisionally- heated by shocked X-ray or line emitting gas. We will use physical models to calculate the radiative and collisional heating of SNR dust, the equilibrium or fluctuating dust temperatures, and the resulting IR emission for various dust compositions and size distributions. Specific examples of Cas A, SN1987A, the Crab Nebula, and Puppis A, are discussed in detail to illustrate our modeling approach. Our study will be the first comprehensive and physical analysis of a large sample of SNRs in different evolutionary states and different astrophysical environments. They will cover a wide range of interactions between the dust grains and their surroundings, including the radioactively- powered and/or shocked SN ejecta, hard X-rays and EUV radiation fields, and shocked circumstel- lar/interstellar gas. Our study will shed light on the evolution of dust grains from their explosive formation sites, through their violent injection into the ISM, and ultimate demise or survival as they travel through a network of interstellar shock waves. It will constitute a major advance in our understanding of the origin and evolution of dust in the Milky Way, in galaxies in general, and especially in the early universe.

Dwek, Eli

262

Strong evidence for hadron acceleration in Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

Context. Very recent gamma-ray observations of G120.1+1.4 (Tycho's) supernova remnant (SNR) by Fermi-LAT and VERITAS have provided new fundamental pieces of information for understanding particle acceleration and nonthermal emission in SNRs. Aims: We want to outline a coherent description of Tycho's properties in terms of SNR evolution, shock hydrodynamics, and multiwavelength emission by accounting for particle acceleration at the forward shock via first-order Fermi mechanism. Methods: We adopt here a quick and reliable semi-analytical approach to nonlinear diffusive shock acceleration. It includes magnetic field amplification due to resonant streaming instability and the dynamical backreaction on the shock of both cosmic rays (CRs) and self-generated magnetic turbulence. Results: We find that Tycho's forward shock accelerates protons up to at least 500 TeV, channelling into CRs about 10% of its kinetic energy. Moreover, the CR-induced streaming instability is consistent with all the observational evidence of very efficient magnetic field amplification (up to ~300 ?G). In such a strong magnetic field, the velocity of the Alfvn waves scattering CRs in the upstream is expected to be enhanced and to make accelerated particles feel an effective compression factor lower than 4, in turn leading to an energy spectrum steeper than the standard prediction ? E-2. This effect is crucial for explaining GeV-to-TeV gamma-ray spectrum as the result of neutral pions decay produced in nuclear collisions between accelerated nuclei and the background gas. Conclusions: The self-consistency of such hadronic scenario, along with the inability of the concurrent leptonic mechanism (inverse Compton scattering of relativistic electrons on several photon backgrounds) to reproduce both the shape and the normalization of the detected gamma-ray emission, represents the first clear and direct radiative evidence that hadron acceleration occurs efficiently in young Galactic SNRs.

Morlino, G.; Caprioli, D.

2012-02-01

263

ON THE EXISTENCE OF 'RADIO THERMALLY ACTIVE' GALACTIC SUPERNOVA REMNANTS  

SciTech Connect

In this paper, we investigate the possibility of significant production of thermal bremsstrahlung radiation at radio continuum frequencies that could be linked to some Galactic supernova remnants (SNRs). The main targets for this investigation are SNRs expanding in high-density environments. There are several indicators of radio thermal bremsstrahlung radiation from SNRs, such as a flattening at higher frequencies and thermal absorption at lower frequencies intrinsic to an SNR. In this work, we discuss the radio continuum properties of three SNRs that are the best candidates for testing our hypothesis of significant thermal emission. In the case of SNRs IC 443 and 3C 391, thermal absorption has been previously detected. For IC 443, the contribution of thermal emission at 1 GHz, from our model fit is 3%-57%. It is similar to the estimate obtained from the thermal absorption properties (10%-40% at 1 GHz). In the case of the 3C 391 the conclusions are not so clear. The results from our model fit (thermal emission contribution of 10%-25% at 1 GHz) and results obtained from the low-frequency absorption (thermal contribution of 0.15%-7% at 1 GHz) do not overlap. For the SNR 3C 396 we suggest that if previously detected thermal absorption could be intrinsic to the SNR then the thermal emission (<47% at 1 GHz from our model fit) could be significant enough to shape the radio continuum spectrum at high frequencies. Polarization observations for these SNRs can constrain the strength of a thermal component. Reliable observations at low frequencies (<100 MHz) are needed as well as more data at high radio frequencies (>1 GHz), in order to make stronger conclusions about the existence of 'radio thermally active' SNRs.

Onic, D.; Urosevic, D.; Arbutina, B. [Department of Astronomy, Faculty of Mathematics, University of Belgrade (Serbia); Leahy, D. [Department of Physics and Astronomy, University of Calgary (Canada)

2012-09-01

264

Inverse Compton Emission from Galactic Supernova Remnants: Effect of the Interstellar Radiation Field  

SciTech Connect

The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV {gamma}-rays; long awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the ''knee'' energies. Still, uncertainty exists whether these {gamma}-rays are produced by electrons via inverse Compton scattering or by protons via {pi}{sup 0}-decay. The multi-wavelength spectra of supernova remnants can be fitted with both mechanisms, although a preference is often given to {pi}{sup 0}-decay due to the spectral shape at very high energies. A recent study of the interstellar radiation field indicates that its energy density, especially in the inner Galaxy, is higher than previously thought. In this paper we evaluate the effect of the interstellar radiation field on the inverse Compton emission of electrons accelerated in a supernova remnant located at different distances from the Galactic Centre. We show that contribution of optical and infra-red photons to the inverse Compton emission may exceed the contribution of cosmic microwave background and in some cases broaden the resulted {gamma}-ray spectrum. Additionally, we show that if a supernova remnant is located close to the Galactic Centre its {gamma}-ray spectrum will exhibit a ''universal'' cutoff at very high energies due to the Klein-Nishina effect and not due to the cut-off of the electron spectrum. As an example, we apply our calculations to the supernova remnants RX J1713.7-3946 and G0.9+0.1 recently observed by HESS.

Porter, Troy A.; /UC, Santa Cruz; Moskalenko, Igor V.; /Stanford U., HEPL; Strong, Andrew W.; /Garching, Max Planck Inst., MPE

2006-08-01

265

N157B: X-ray evidence for a Crab-like supernova remnant  

NASA Technical Reports Server (NTRS)

The X-ray observation of the supernova remnant N 157B is described. The Rosat High Resolution Imager (HRI) X-ray emission from the remnant was decomposed into point-like sources. The spectra showed abundance-enhanced neon and magnesium lines, indicating that the remnant originated in a massive progenitor. The flat and featureless data from the Advanced Satellite for Cosmology and Astrophysics (ASCA) confirm the Crab-like nature of the remnant. By interpreting both the thermal spectral component and the shell as representing the remnant's outer shock, the age of the remnant was estimated to be 4 x 10(exp 3) yr and the energy release approximately 2 x 10(exp 50) erg.

Gotthelf, Eric V.; Wang, Q. Daniel

1996-01-01

266

DISCOVERY OF X-RAY EMISSION FROM SUPERNOVA 1970G WITH CHANDRA: FILLING THE VOID BETWEEN SUPERNOVAE AND SUPERNOVA REMNANTS  

NASA Technical Reports Server (NTRS)

We report the discovery of X-ray emission from SN 1970G in M101, 35 yr after its outburst, using deep X-ray imaging with the Chundra X-Ray Observatory. The Chandra ACIS spectrum shows that the emission is soft (52 keV) and characteristic of the reverse-shock region. The X-ray luminosity, Lo,,, = (1.1 3 0.2) x lo3# ergs s-1, is likely caused by the interaction of the supernova shock with dense circumstellar matter. If the material was deposited by the stellar wind from the progenitor, a mass-loss rate of M = (2.6 ? 0.4) x M, yr-I (v,/lO km s-I) is inferred. Utilizing the high-resolution Chandra ACIS data of SN 1970G and its environment, we reconstruct the X-ray lightcurve from previous ROSAT HRI, PSPC, and XMM-Newton EPIC observations, and find a best-fit linear rate of decline of L cc t-# with index s = 2.7 t 0.9 over a period of -20-35 yr after the outburst. As the oldest supernova detected in X-rays, SN 1970G allows, for the first time, direct observation of the transition from a supenova to its supernova remnant phase.

Immler, Stefan; Kuntz, K. D.

2005-01-01

267

Supernova Ejecta in the Youngest Galactic Supernova Remnant G1.9+0.3  

E-print Network

G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of about 1900, and most likely located near the Galactic Center. Only the outermost ejecta layers with free-expansion velocities larger than about 18,000 km/s have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially-resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet-based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs: Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe Kalpha emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating tha...

Borkowski, K J; Hwang, U; Green, D A; Petre, R; Krishnamurthy, K; Willett, R

2013-01-01

268

A Dust Twin of Cas A: 21-micron Dust Feature in The Supernova Remnant G54.1+0.3  

NASA Astrophysics Data System (ADS)

We present Spitzer and submm observations of a Crab-like supernova remnant, G54.1+0.3. We serendipitously discovered a dust feature peaking at 21 micron from G54.1+0.3, and the 21-micron dust is remarkably similar to that of Cas A from Rho et al. (2008). The IRS spectrum from the western shell shows the 21-micron dust feature and strong [Ar II] and weak [Ne II], [S III] and [Si II] lines. Strong correlation between 21-micron dust and Ar ejecta has been observed in Cas A. IRAC 8-micron emission mostly from Ar ejecta shows shell-like morphology and MIPS 24 and 70 micron emission from continuum also show shell-like morphology, suggesting that dust has been formed in ejecta. The shell-like ejecta distribution around pulsar wind nebula is analogy with that of the Crab Nebula. We detected submm emission from G54.1+0.3 using SHARCII (at 350 micron) and LABOCA (at 870 micron). We present dust fitting using continuous distributions of ellipsoidal (CDE) grain models. Spectral fitting requires a combination of dust composition including SiO2, SiC, and Al2O3 which are responsible for 21-micron, 11 micron dust features and long-wavelength continuum, respectively. We will discuss dust properties and inferred dust mass from G54.1+0.3 and implication of supernova-dust production in early Universe. I also show how SOFIA (Stratospheric Observatory for Infrared Astronomy) can help in study-ing supernova remnants at mid-and far-infrared and submm.

Rho, Jeonghee; Gomez, H.; Lagage, P.-O.; Boogert, A.; Reach, W. T.; Dowell, D.

269

Validating the Supernova Remnant Hypothesis of the Cosmic Ray Origin  

NASA Astrophysics Data System (ADS)

The century-old problem of the origin and acceleration of cosmic rays (CR) could soon be resolved. However, as it is impossible to trace CR back to their accelerators because of orbit scrambling in the galactic magnetic field, the solution will not be easy. Also the direct observations of a secondary gamma emission from supernova remnant (SNR) shocks, long suspected to be the main source of galactic CRs, are complicated by the contaminating electron emission. Therefore, the SNR hypothesis of the CR origin can be proven beyond a reasonable doubt only if the acceleration theory is fully consistent with the observations. However, the complexity of plasma dynamics in SNR shocks makes the validation of the SNR hypothesis very difficult. A study of the crucial plasma processes in SNR shocks is proposed. It will determine the three-way partitioning of the shock energy between accelerated particles (protons and electrons), turbulent magnetic fields and thermal plasma. The project includes a comparative analysis of three instabilities, arguably crucial to the diffusive shock acceleration (DSA) mechanism: i.) the cyclotron resonance CR instability, ii.) the non- resonant CR-current driven (kink-type) instability and iii.) the acoustic CR-pressure gradient driven instability. By identifying the dominant instability depending on the local SNR environment, the spectra of different species of accelerated particles, their losses, and the broadband radiation will be calculated and compared to both direct observations of the secondary emission from major SNRs and to the measurements of the background CRs. The comparison will show whether the DSA mechanism production of CR in SNR is consistent with the observed emission. The remnants most visible in gamma rays expand into weakly ionized, dense gases. The physics of the CR production in such environments based on the three instabilities will be studied. The proposer's previous work has shown that the propagation of CRs in a dense SNR surrounding should result in a break in the particle and gamma-ray emission spectra, now frequently observed in such SNRs. The theoretical studies and modeling of the breaks, resulting from interactions of CR with a self-driven wave turbulence, will be carried out for conditions relevant to the observed SNRs. The problem of disentangling electron and proton emissions will be addressed. To this end, a new mechanism of electron injection into the DSA will be examined. This mechanism is based on a macroscopic electric field generated by the current-driven turbulence and penetration of CR into weakly ionized gas upstream. The electric field can accelerate electrons, leading to runaway. This process is well known from laboratory plasma research, so the proposers expertise in magnetic confinement studies will be utilized. The escape of accelerated particles into the SNR surroundings are studied separately from this proposal and may also become useful for the purpose of electron/proton differentiation. This will be based, in particular but not exclusively, on the fact that the proton high energy emission pattern is correlated with the ambient dense gas distribution, as opposed to the inverse Compton electron emission. CRs play a fundamental role in our understanding of the structure and evolution of the universe and the mystery of their origin is longstanding and difficult to solve. Very recent revolutionary improvements in SNR observations and CR measurements, including such NASA missions as Fermi and Chandra offer a unique chance for a theoretical breakthrough in validating the SNR hypothesis of the origin of galactic CRs. The proposers will be able to analytically predict CR spectral features, such as breaks and spectral slope variations among different elements. As these features are unique to the DSA, their comparison with the data will help to determine whether the DSA mechanism is indeed responsible for the production of galactic CR in SNRs.

Malkov, Mikhail

270

Surprisingly high-pressure shocks in the supernova remnant IC 443  

NASA Technical Reports Server (NTRS)

The intensities of several lines of molecular hydrogen have been measured from two regions of the supernova-remnant/molecular-cloud shock in IC 443. The lines measured have upper-state energies ranging from 7000 K to 23,000 K. Their relative intensities differ in the two regions, but are consistent with those predicted from the post-shock regions of simple jump-type shocks of different pressure. The pressures so derived are far higher than the pressure in the supernova remnant itself, and a possible reason for this discrepancy is discussed.

Moorhouse, A.; Brand, P. W. J. L.; Geballe, T. R.; Burton, M. G.

1991-01-01

271

Three-Dimensional Kinematics of the Supernova Remnant Puppis A  

NASA Astrophysics Data System (ADS)

We present proper-motion and radial-velocity studies of ejecta-dominated filaments in the young core-collapse SNR Puppis A. Using CCD images from CTIO at seven epochs 1989-2008, we have measured proper motions for dozens of ejecta-dominated knots. While the results appear qualitatively similar to our 1988 proper-motion study based on photographic plates (Winkler et al., IAU Colloq. 101), the current study--the first to use CCD data--includes many more filaments and spans a longer baseline to give far more precise values. We find proper motions as large as 0.22 arcsec/yr, equivalent to a transverse velocity of 2100 km/s at the 2 kpc distance to Puppis A. Like the previous study, the current one shows almost all the ejecta knots are expanding from a central location into the NE quadrant of the SNR. The direction is generally opposite to that of the unresolved central X-ray source RX J0822-4300, whose motion to the SW at >1200 km/s has been interpreted as the recoil of a compact remnant from the explosion (Hui & Becker, 2006 A & A; Winkler & Petre, 2007 ApJ). In addition, we have measured radial velocities for dozens of knots, based on spectra from the long-slit RC spectrograph on the CTIO 1.5m telescope and from the Hydra multi-object spectrograph on the Blanco 4m. This sample shows radial velocities from -1600 km/s to +1000 km/s. If we assume undecelerated expansion of all the knots from a common center, the radial velocities are equivalent to position along the line of sight, so we can construct a 3-dimensional model for the structure and kinematics of Puppis A's ejecta. We discuss the implications of the observed kinematics for core-collapse supernovae and the kicks they give to neutron stars they produce. This work is supported by the NSF through grant AST-0908566.

Garber, Jillian; Long, K. S.; Waite, C. W.; Winkler, P. F.

2010-01-01

272

Supernova remnants and diffuse ionized gas in M31  

NASA Technical Reports Server (NTRS)

Researchers have compiled an initial list of radio/optical supernova remnants (SNRs) in M31, by searching for radio identifications of emission-line sources with a high (SII)/H alpha ratio (greater than 0.60). The (SII) filter included both sulfur lines and the H alpha filter did not include (NII). This search revealed 11 SNRs, of which only two were known. In addition, researchers detected radio emission from 3 SNRs that were identified in previous optical surveys (D'Odorico et al., 1980), but that were outside the charge coupled device (CCD) fields. The 14 objects only include the most obvious candidates, but a full search is in progress and the researchers expect to find several more SNRs. Also not all optical SNRs show detectable radio emission and a pure optical list of SNR candidates based only on the ratio of (SII)/H alpha emission contains many more objects. Two conclusions are apparent. First, the radio properties of the SNRs in M31 are quite similar to those of Galactic SNRs as is illustrated. The brightnesses are not systematically lower as has been suggested in the past (Dickel and D'Odorico, 1984). Second, the slope of the relation is close to -2; this slope is expected from the intrinsic dependence between surface brightness and diameter. The radio luminosity of the SNRs does not seem to depend strongly on diameter, or age, contrary to model predictions. Selection effects, however, play an important role in these plots. The CCD images show widespread diffuse ionized gas with a ratio of (SII)/H alpha that is higher than that of discrete HII regions. Discrete HII regions typically show ratios between 0.2 to 0.3, while the diffuse gas in the arms consistently shows ratios of 0.5. Researchers can trace this gas across the spiral arms to emission measures below 5 pc cm (-6). Its properties seem to be similar to that of the diffuse gas in the solar neighborhood.

Walterbos, Rene; Braun, Robert

1990-01-01

273

Updated Radio Sigma-D Relation for Galactic Supernova Remnants  

NASA Astrophysics Data System (ADS)

We present the updated empirical radio surface-brightness-to-diameter (Sigma - D) relation for supernova remnants (SNRs) in our Galaxy. Our original calibration sample of Galactic SNRs with independently determined distances (Pavlovic et al. 2013, hereafter Paper I) is reconsidered and updated with data which became available in the past two years. The orthogonal fitting procedure and probability-density-function-based (PDF) method are applied to the calibration sample in the log Sigma - log D plane. Non-standard orthogonal regression keeps the Sigma-D and D-Sigma relations invariant within estimated uncertainties. Our previous Monte Carlo simulations verified that the slopes of the empirical Sigma-D relation should be determined by using the orthogonal regression, because of its good performances for data sets with severe scatter. The updated calibration sample contains 65 shell SNRs. 6 new Galactic SNRs are added to the sample from Paper I, one is omitted and distances are changed for 10 SNRs. The slope derived is here slightly steeper (? ? 5.2) than the Sigma-D slope in Paper I (? ? 4.8). The PDF method relies on data points density maps which can provide more reliable calibrations that preserve more information contained in the calibration sample. We estimate distances to five new faint Galactic SNRs discovered for the first time by Canadian Galactic Plane Survey, and obtained distances of 2.3, 4.0, 1.3, 2.9 and 4.7 kiloparsecs for G108.5+11.0, G128.5+2.6, G149.5+3.2, G150.8+3.8 and G160.1-1.1, respectively. The updated empirical relation is used to estimate distances of 160 shell Galactic SNRs and new results change their distance scales up to 15 per cent, compared to the results from Paper I. The PDF calculation can provide even few times higher or lower values in comparison with the orthogonal fit, as it uses a totally different approach. However, on average, this difference is 32, 24 and 18 per cent for mode, median and mean distances.

Pavlovic, M. Z.; Dobardzic, A.; Vukotic, B.; Urosevic, D.

2014-12-01

274

The laboratory simulation of unmagnetized supernova remnants Absence of a blast wave  

NASA Technical Reports Server (NTRS)

Supernova remnants are experimentally simulated by irradiating spherical targets with eight-beam carbon dioxide laser in a chamber containing finite amounts of neutral gas, the gas being ionized by radiation from the hot target. The expansion velocities of the target plasmas are approximately the same as the expansion velocities of supernova ejecta and the experiment is successfully scaled to the case of a supernova remnant in an unmagnetized, low-density, interstellar medium. No sweep-up of the ambient plasma is detected, indicating that no hydrodynamic shock wave is formed to couple the target ejecta to the ambient gas. The experiment implies that if supernova ejecta couple to the interstellar medium, magnetic-field effects may be crucial to the physical description.

Borovsky, J. E.; Pongratz, M. B.; Roussel-Dupre, R. A.; Tan, T.-H.

1984-01-01

275

DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY  

SciTech Connect

A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

Seward, F. D. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Charles, P. A. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Foster, D. L. [South African Astronomical Observatory, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Dickel, J. R.; Romero, P. S. [Department of Physics and Astronomy, University of New Mexico, 1919 Lomas Boulevard NE, Albuquerque, NM 87131 (United States); Edwards, Z. I.; Perry, M.; Williams, R. M. [Department of Earth and Space Sciences, Columbus State University, Coca Cola Space Science Center, 701 Front Avenue, Columbus, GA 31901 (United States)

2012-11-10

276

Investigation of Supernova Remnant Shocks in the Vela-Puppis Region  

NASA Technical Reports Server (NTRS)

Overview: We observed supernova remnant (SNR) shocks at four locations in the Vela- Puppis region. The targets were a bright X-ray knot in the center of the remnant, Knot D on the eastern limb of the remnant, a region overlapping the Puppis A SNR and a region within Vela overlapping the edge of the SNR Rx10852.0-4622. The aim of the observations was to characterize the properties of the shocks and identify separate kinematic components of the emission. The first round of analysis of these data produced significant interesting results as outlined below. Further analyses, in conjunction with other datasets, are planned.

Sankrit, Ravi

2005-01-01

277

The x-ray structure of the supernova remnant W49B  

NASA Astrophysics Data System (ADS)

Comparison of x-ray and radio images of W49B and other supernova remnants (SNR) provides detailed information on the mechanisms responsible for the emission and on the evolution of the remnants. There is faint x-ray emission from all parts of W49B but most of it is concentrated near the center of the remnant, unlike the radio emission which arises in a shell near the periphery. This structure indicates that this SNR is in the adolescent phase of its lifetime.

Dickel, John R.; Murphy, Rosa; Chu, You-Hua; Garcia, Guillermo; Goscha, Daniel

278

Ongoing cosmic ray acceleration in the supernova remnant W51C revealed with the MAGIC telescopes  

NASA Astrophysics Data System (ADS)

The supernova remnant (SNR) W51C interacts with the molecular clouds of the star-forming region W51B, making the W51 complex one of the most promising targets to study cosmic ray acceleration. Gamma-ray emission from this region was discovered by Fermi/LAT and H.E.S.S., although its location was compatible with the SNR shell, the molecular cloud (MC) and a pulsar wind nebula (PWN) candidate. The modeling of the spectral energy distribution presented by the Fermi/LAT collaboration suggests a hadronic emission mechanism. Furthermore indications of an enhanced flux of low energy cosmic rays in the interaction region between SNR and MC have been reported based on ionization measurements in the mm regime. MAGIC conducted deep observations of W51, yielding a detection of an extended emission with more than 11 standard deviations. We extend the spectrum from the highest Fermi/LAT energies to ~5 TeV and find that it follows a single power law with an index of 2.58+/-0.07stat+/-0.22syst. We restrict the main part of the emission region to the zone where the SNR interacts with the molecular clouds. We also find a tail extending towards the PWN candidate CXO J192318.5+140305, possibly contributing up to 20% of the total flux. The broad band spectral energy distribution can be explained with a hadronic model that implies proton acceleration at least up to 50 TeV. This result, together with the morphology of the source, suggests that we observe ongoing acceleration of ions in the interaction zone between the SNR and the cloud.

Krause, J.; Reichardt, I.; Carmona, E.; Gozzini, S. R.; Jankowski, F.; MAGIC Collaboration

2012-12-01

279

IRAS observations of supernova remnants - A comparison between their infrared and X-ray cooling rates  

NASA Technical Reports Server (NTRS)

A comparison is presented between the total IR and X-ray cooling rates of nine selected Galactic supernova remnants. The observed IR-to-X-ray cooling ratio (IRX ratio) values are larger than unity for most remnants, ranging from five for the adiabatic remnant Puppis A, to about 1000 for RCW 86. Most of the observed IR emission from the remnants can be attributed to thermal emission from dust collisionally heated by the shocked plasma. A comparison between the theoretical and observed IRX ratio shows that only two of the nine remnants have IRX ratios within a factor of about three of the expected value. Puppis A, Kepler, Tycho, and SN 1006 have IRX ratios that are significantly smaller than the theoretically predicted value, suggesting that the dust is significantly depleted in the ambient medium into which they are expanding.

Dwek, Eli; Petre, Robert; Szymkowiak, Andrew; Rice, Walter L.

1987-01-01

280

The Evolution of Mass Loaded Supernova Remnants. II. Temperature Dependent Mass Injection Rates  

E-print Network

We investigate the evolution of spherically symmetric supernova remnants in which mass loading takes place due to conductively driven evaporation of embedded clouds. Numerical simulations reveal significant differences between the evolution of conductively mass loaded and the ablatively mass loaded remnants studied in Paper I. A main difference is the way in which conductive mass loading is extinguished at fairly early times, once the interior temperature of the remnant falls below ~10 million K. Thus, at late times remnants that ablatively mass load are dominated by loaded mass and thermal energy, while those that conductively mass load are dominated by swept-up mass and kinetic energy. Simple approximations to the remnant evolution, complementary to those in Paper I, are given.

J. M. Pittard; S. J. Arthur; J. E. Dyson; S. A. E. G. Falle; T. W. Hartquist; M. I. Knight; M. Pexton

2003-03-12

281

Measuring the Magnetic Fields of Central Compact Objects in Supernova Remnants  

NASA Astrophysics Data System (ADS)

X-ray timing studies of two X-ray pulsars in SNRs have detected no braking of their rotation, implying upper limits of 3E11 G on their surface dipole fields, well below those of ordinary young pulsars. We proposed that weak B-fields related to slow natal spin may be the physical basis of the class of Central Compact Objects (CCOs), including the unseen pulsar in SN 1987A. This proposal leverages existing timing data on CCO pulsars to determine if they are spinning down and, if so, to measure their magnetic fields by obtaining coherent timing solutions linking all previous data. Fields as small as 1E10 G can be measured in this way. Alternatively, accretion of supernova debris through a fallback disk may be occurring, which would be detectable as torque noise.

Halpern, Jules

2007-10-01

282

Measuring the Magnetic Fields of Central Compact Objects in Supernova Remnants  

NASA Astrophysics Data System (ADS)

X-ray timing studies of two X-ray pulsars in SNRs have detected no braking of their rotation, implying upper limits of 3E11 G on their surface dipole fields, well below those of ordinary young pulsars. We proposed that weak B-fields related to slow natal spin may be the physical basis of the class of Central Compact Objects (CCOs), including the unseen pulsar in SN 1987A. This proposal leverages existing timing data on CCO pulsars to determine if they are spinning down and, if so, to measure their magnetic fields by obtaining coherent timing solutions linking all previous data. Fields as small as 1E10 G can be measured in this way. Alternatively, accretion of supernova debris through a fallback disk may be occurring, which would be detectable as torque noise.

Halpern, Jules

2008-09-01

283

RADIO DETECTION OF A CANDIDATE NEUTRON STAR ASSOCIATED WITH GALACTIC CENTER SUPERNOVA REMNANT SAGITTARIUS A EAST  

SciTech Connect

We report the Very Large Array (VLA) detection of the radio counterpart of the X-ray object referred to as the 'Cannonball', which has been proposed to be the remnant neutron star resulting from the creation of the Galactic center supernova remnant, Sagittarius A East. The radio object was detected both in our new VLA image from observations in 2012 at 5.5 GHz and in archival VLA images from observations in 1987 at 4.75 GHz and in the period from 1990 to 2002 at 8.31 GHz. The radio morphology of this object is characterized as a compact, partially resolved point source located at the northern tip of a radio 'tongue' similar to the X-ray structure observed by Chandra. Behind the Cannonball, a radio counterpart to the X-ray plume is observed. This object consists of a broad radio plume with a size of 30''15'', followed by a linear tail having a length of 30''. The compact head and broad plume sources appear to have relatively flat spectra (??{sup ?}) with mean values of ? = 0.44 0.08 and 0.10 0.02, respectively, and the linear tail shows a steep spectrum with the mean value of 1.94 0.05. The total radio luminosity integrated from these components is ?8 10{sup 33} erg s{sup 1}, while the emission from the head and tongue amounts for only ?1.5 10{sup 31} erg s{sup 1}. Based on the images obtained from the two epochs' observations at 5 GHz, we infer the proper motion of the object: ?{sub ?} = 0.001 0.003 arcsec yr{sup 1} and ?{sub ?} = 0.013 0.003 arcsec yr{sup 1}. With an implied velocity of 500 km s{sup 1}, a plausible model can be constructed in which a runaway neutron star surrounded by a pulsar wind nebula was created in the event that produced Sgr A East. The inferred age of this object, assuming that its origin coincides with the center of Sgr A East, is approximately 9000 yr.

Zhao, Jun-Hui [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 78, Cambridge, MA 02138 (United States); Morris, Mark R. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Goss, W. M., E-mail: jzhao@cfa.harvard.edu, E-mail: morris@astro.ucla.edu, E-mail: mgoss@aoc.nrao.edu [NRAO, P.O. Box O, Socorro, NM 87801 (United States)

2013-11-10

284

Radio Detection of a Candidate Neutron Star Associated with Galactic Center Supernova Remnant Sagittarius A East  

NASA Astrophysics Data System (ADS)

We report the Very Large Array (VLA) detection of the radio counterpart of the X-ray object referred to as the "Cannonball," which has been proposed to be the remnant neutron star resulting from the creation of the Galactic center supernova remnant, Sagittarius A East. The radio object was detected both in our new VLA image from observations in 2012 at 5.5 GHz and in archival VLA images from observations in 1987 at 4.75 GHz and in the period from 1990 to 2002 at 8.31 GHz. The radio morphology of this object is characterized as a compact, partially resolved point source located at the northern tip of a radio "tongue" similar to the X-ray structure observed by Chandra. Behind the Cannonball, a radio counterpart to the X-ray plume is observed. This object consists of a broad radio plume with a size of 30''15'', followed by a linear tail having a length of 30''. The compact head and broad plume sources appear to have relatively flat spectra (vprop??) with mean values of ? = -0.44 0.08 and -0.10 0.02, respectively, and the linear tail shows a steep spectrum with the mean value of -1.94 0.05. The total radio luminosity integrated from these components is ~8 1033 erg s-1, while the emission from the head and tongue amounts for only ~1.5 1031 erg s-1. Based on the images obtained from the two epochs' observations at 5 GHz, we infer the proper motion of the object: ?? = 0.001 0.003 arcsec yr-1 and ?? = 0.013 0.003 arcsec yr-1. With an implied velocity of 500 km s-1, a plausible model can be constructed in which a runaway neutron star surrounded by a pulsar wind nebula was created in the event that produced Sgr A East. The inferred age of this object, assuming that its origin coincides with the center of Sgr A East, is approximately 9000 yr.

Zhao, Jun-Hui; Morris, Mark R.; Goss, W. M.

2013-11-01

285

SUPERNOVA EJECTA IN THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3  

SciTech Connect

G1.9+0.3 is the youngest known Galactic supernova remnant (SNR), with an estimated supernova (SN) explosion date of {approx}1900, and most likely located near the Galactic center. Only the outermost ejecta layers with free-expansion velocities {approx}>18,000 km s{sup -1} have been shocked so far in this dynamically young, likely Type Ia SNR. A long (980 ks) Chandra observation in 2011 allowed spatially resolved spectroscopy of heavy-element ejecta. We denoised Chandra data with the spatio-spectral method of Krishnamurthy et al., and used a wavelet-based technique to spatially localize thermal emission produced by intermediate-mass elements (IMEs; Si and S) and iron. The spatial distribution of both IMEs and Fe is extremely asymmetric, with the strongest ejecta emission in the northern rim. Fe K{alpha} emission is particularly prominent there, and fits with thermal models indicate strongly oversolar Fe abundances. In a localized, outlying region in the northern rim, IMEs are less abundant than Fe, indicating that undiluted Fe-group elements (including {sup 56}Ni) with velocities >18,000 km s{sup -1} were ejected by this SN. However, in the inner west rim, we find Si- and S-rich ejecta without any traces of Fe, so high-velocity products of O-burning were also ejected. G1.9+0.3 appears similar to energetic Type Ia SNe such as SN 2010jn where iron-group elements at such high free-expansion velocities have been recently detected. The pronounced asymmetry in the ejecta distribution and abundance inhomogeneities are best explained by a strongly asymmetric SN explosion, similar to those produced in some recent three-dimensional delayed-detonation Type Ia models.

Borkowski, Kazimierz J.; Reynolds, Stephen P. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Hwang, Una [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Green, David A. [Cavendish Laboratory, 19 J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Petre, Robert [NASA/GSFC, Code 660, Greenbelt, MD 20771 (United States); Krishnamurthy, Kalyani; Willett, Rebecca, E-mail: kborkow@unity.ncsu.edu [Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708 (United States)

2013-07-01

286

A New Sigma -D Relation and Its Application to the Galactic Supernova Remnant Distribution  

Microsoft Academic Search

Technological advances in radio telescopes and X-ray instruments over the last 20 years have greatly increased the number of known supernova remnants (SNRs) and have led to a better determination of their properties. In particular, more SNRs now have reasonably determined distances. However, many of these distances were determined kinematically using old rotation curves (based on R&sun; = 10 kpc

Gary L. Case; Dipen Bhattacharya

1998-01-01

287

Iron and Nickel Abundances in H II Regions and Supernova Remnants  

Microsoft Academic Search

Iron and Nickel abundances in H II regions and supernova remnants (SNRs) are known to be abnormal compared to cosmic abundances. Estimates of the Iron abundance are up to ten times lower than solar (thought to be due to grain depletion), and the abundance of Nickel ranges from about solar to several times solar for many different objects, such as

Manuel A. Bautista; Anil K. Pradhan

1995-01-01

288

Kinetic theory of cosmic rays and gamma rays in supernova remnants. I. Uniform interstellar medium  

Microsoft Academic Search

Kinetic models of particle acceleration in supernova remnants (SNRs) are used to determine the cosmic ray (CR) nucleon and, for the first time, also the associated ?-ray spectrum during SN shock propagation in a uniform interstellar medium. SNR evolution is followed numerically taking into account the backreaction of accelerated CRs on the overall dynamics. The high energy CRs also produce

E. G. Berezhko; H. J. Vlk

1997-01-01

289

Kinetic theory of cosmic rays and gamma rays in supernova remnants. I. Uniform interstellar medium  

Microsoft Academic Search

Kinetic models of particle acceleration in supernova remnants (SNRs) are used to determine the cosmic ray (CR) nucleon and, for the first time, also the associated gamma-ray spectrum during SN shock propagation in a uniform interstellar medium. SNR evolution is followed numerically taking into account the backreaction of accelerated CRs on the overall dynamics. The high energy CRs also produce

E. G. Berezhko; H. J. Vlk

1997-01-01

290

Cosmic-ray diffusion near the Bohm limit in the Cassiopeia A supernova remnant  

E-print Network

ARTICLES Cosmic-ray diffusion near the Bohm limit in the Cassiopeia A supernova remnant M. D. STAGE made it possible to image the keV-scale synchrotron emission produced by cosmic-ray electrons been the leading candidates for the acceleration of cosmic rays1,2 . Diffusive shock acceleration

Loss, Daniel

291

FERMI -LAT OBSERVATIONS AND A BROADBAND STUDY OF SUPERNOVA REMNANT CTB 109  

E-print Network

CTB 109 (G109.1-1.0) is a Galactic supernova remnant (SNR) with a hemispherical shell morphology in X-rays and in the radio band. In this work, we report the detection of ?-ray emission coincident with CTB 109, using 37 ...

Castro, Daniel

292

Discriminating the Progenitor Type of Supernova Remnants with Iron K-shell Emission  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) retain crucial information about both their parent explosion and circumstellar material left behind by their progenitor. However, the complexity of the interaction between supernova ejecta and ambient medium often blurs this information, and it is not uncommon for the basic progenitor type (Ia or core-collapse) of well-studied remnants to remain uncertain. Here we present a powerful new observational diagnostic to discriminate between progenitor types and constrain the ambient medium density of SNRs using solely Fe K-shell X-ray emission. We analyze all extant Suzaku observations of SNRs and detect Fe K? emission from 23 young or middle-aged remnants, including five first detections (IC 443, G292.0+1.8, G337.2-0.7, N49, and N63A). The Fe K? centroids clearly separate progenitor types, with the Fe-rich ejecta in Type Ia remnants being significantly less ionized than in core-collapse SNRs. Within each progenitor group, the Fe K? luminosity and centroid are well correlated, with more luminous objects having more highly ionized Fe. Our results indicate that there is a strong connection between explosion type and ambient medium density, and suggest that Type Ia supernova progenitors do not substantially modify their surroundings at radii of up to several parsecs. We also detect a K-shell radiative recombination continuum of Fe in W49B and IC 443, implying a strong circumstellar interaction in the early evolutionary phases of these core-collapse remnants.

Yamaguchi, Hiroya; Badenes, Carles; Petre, Robert; Nakano, Toshio; Castro, Daniel; Enoto, Teruaki; Hiraga, Junko S.; Hughes, John P.; Maeda, Yoshitomo; Nobukawa, Masayoshi; Safi-Harb, Samar; Slane, Patrick O.; Smith, Randall K.; Uchida, Hiroyuki

2014-04-01

293

Narrow Band Chandra X-ray Analysis of Supernova Remnant 3C391  

E-print Network

We present the narrow-band and the equivalent width (EW) images of the thermal composite supernova remnant (SNR) 3C391 for the X-ray emission lines of elements Mg, Si, & S using the Chandra ACIS Observational data. These EW images reveal the spatial distribution of the emission of the metal species Mg, Si, & S in the remnant. They have clumpy structure similar to that seen from the broadband diffuse emission, suggesting that they are largely of interstellar origin. We find an interesting finger-like feature protruding outside the southwestern radio border of the remnant, which is somewhat similar to the jet-like Si structure found in the famous SNR Cas A. This feature may possibly be the debris of the jet of ejecta which implies an asymmetrical supernova explosion of a massive progenitor star.

Yang Su; Yang Chen

2005-05-02

294

A search for OH 6 GHz maser emission towards southern supernova remnants  

E-print Network

OH masers at 1720 MHz have proven to be excellent indicators of interactions between supernova remnants and molecular clouds. Recent calculations suggest that the 6049 MHz OH maser line is excited for higher column densities than for the 1720 MHz line. It is therefore a potentially valuable indicator of remnant-cloud interaction. We present preliminary results of a survey using the Parkes Methanol Multibeam receiver for 6049 MHz and 6035/6030 MHz OH masers towards 36 supernova remnants and 4 fields in the Large and Small Magellanic Clouds. While no 6049 MHz masers have been found, three new sites of 6035 and 6030 MHz OH maser emission have been discovered in star-forming regions.

Korinne E. McDonnell; Alan E. Vaughan; Mark Wardle

2007-04-18

295

X-ray emission from young supernova remnants - Nonionization equilibrium abundances and emissivities  

NASA Technical Reports Server (NTRS)

X-ray line emission from hot, low-density plasma in young supernova remnants is strongly enhanced by departures from ionization equilibrium. The X-ray emission from a Sedov blast wave has been calculated using a nonequilibrium evolutionary treatment of the ionization structure, and the resulting spectrum has been fitted to HEAO 2 SSS data for Tycho's remnant. These models yield dramatically different elemental abundances for heavy elements (Ne, Mg, Si, S, Ar, Ca, and Fe), compared with two-temperature component equilibrium models of Becker et al. (1979, 1980). Nonequilibrium broad-band X-ray emissivities result in lower mass determinations for the supernova ejecta. Areas of further improvement of remnant X-ray modeling are suggested.

Shull, J. M.

1982-01-01

296

Observation of soft X-ray emission from the supernova remnant HB9  

NASA Technical Reports Server (NTRS)

The number of known X-ray emitting supernova remnants in our galaxy has significantly grown as a result of the soft X-ray survey by the HEAO-1 spacecraft. The HEAO-1 A-2 experiment has observed soft X-ray emission from the old supernova remnant HB9 which lies close to the previously identified X-ray source, Capella. Spectral data and the low optical obscuration in the direction of the remnant suggest that HB9 is a good candidate for detecting Fe XIV coronal forbidden-line emission. Mapping of the coronal line emission in association with the imaging X-ray data expected from HEAO-2 would allow the temperature profile of the emitting shell to be determined in a manner similar to that used by Tuohy, Nousek, and Garmire (1979) for the Cygnus Loop, which is in a similar evolutionary phase to HB9.

Tuohy, I. R.; Clark, D. H.; Garmire, G. P.

1979-01-01

297

An XMM-Newton Search for Crab-like Supernova Remnants  

NASA Technical Reports Server (NTRS)

The primary goals of the study are to search for evidence of non-thermal emission that would suggest the presence of a pulsar in this compact SNR. We have performed the reduction of the EPIC data for this observation, cleaning the data to remove time intervals of enhanced particle background, and have created maps in several energy bands, and on a variety of smoothing scales. We find no evidence for emission from the SNR. Given the small angular size of the SNR, we conclude that rather than being a young remnant, it is actually fairly old, but distant. At its current stage of evolution, the remnant shell has apparently entered the radiative phase, wherein the shell temperature has cooled sufficiently to be either below X-ray-emitting temperatures or at temperatures easily absorbed the foreground interstellar material. We have thus concluded that this SNR is not a viable candidate for a young ejecta-rich or pulsar-driven SNR.

Mushotzky, Richard (Technical Monitor); Slane, Patrick

2005-01-01

298

Interactions Between CRs and MCs in the Vicinity of Supernova Remnants  

NASA Technical Reports Server (NTRS)

Supernovae are incredibly energetic events which drive the dynamic state of the interstellar medium and accelerate cosmic rays up to energies of a few PeV. I present multi-wavelength observations constraining the shocks, chemistry, dust grain processing, and magnetic fields in a large sample of supernova remnants interacting with dense clouds. These are among the most luminous Galactic sources detected by the Fermi Gamma-Ray Space Telescope. Surprisingly, spectral breaks are seen between GeV and TeV energies. Radio spectral breaks have also been detected for a few remnants, providing clear evidence that supernovae are a significant source of hadronic cosmic rays in the Galaxy. Resolving the origin of these spectral breaks will allow the physics of cosmic ray acceleration and diffusion to be probed.

Hewitt, John W.

2011-01-01

299

Supernova Remnants Interacting with Molecular Clouds:. a New way to Reveal Cosmic Rays  

NASA Astrophysics Data System (ADS)

Molecular clouds interact with the ambient cosmic rays. The decay of secondary particles may give rise to a detectable flux of very high-energy photons. Recently the H.E.S.S., MAGIC and VERITAS telescopes have observed such sources associated with large molecular clouds and shell-type supernova remnants. Emission lines of OH masers are also observed in coincidence. This ensures that the expanding wave front of the supernova interacts effectively with the cloud. Such natural configurations bring new material to confront with the hypothesis that supernova remnants are the Galactic cosmic-ray accelerators. We describe the approach towards a systematic observation of such associations, present the current data and review the prospects of these studies for answering the question of the origin of the Galactic cosmic rays.

Feinstein, F.; Fiasson, A.

2011-03-01

300

Neutral hydrogen in the vicinity of the supernova remnant HB 9  

NASA Astrophysics Data System (ADS)

The neutral hydrogen emission at 21 cm has been investigated with the RATAN-600 radio telescope in the vicinity of the supernova remnant HB9. A clumpyHI shell with radial motions surrounding the remnant has been detected. Its measured parameters contradict the connection with a shock wave from a supernova explosion. The shell formation under the action of a wind from a star that exploded as a supernova at the end of its evolution seems more realistic. The characteristics of the star obtained from the observed shell parameters are the following: a wind power of 0.5 1038 erg s-1, a mass-loss rate of 3.7 10-5 M ? yr-1, and an age of 3 106 yr. Given the measurement errors, the mass of the star is estimated to be >8 M ?.

Gosachinskii, I. V.

2013-03-01

301

How Do The Properties of Light Help Us To Study Supernovae and Their Remnants?  

NSDL National Science Digital Library

This resource describes special properties of light that can help us to understand objects that are millions and billions of light years away. Students explore some of these properties and how they can use them to understand our universe. They will understand that superheated material created by the supernova explosion gives off X-rays and gamma-rays. They will find the answers to questions such as what electromagnetic (EM) radiation is and what units are used to characterize it. They also learn that it pays to make multiple observations of astronomical objects, since they emit light of different energies, that supernovae remnants can give off visible light, ultraviolet light, radio waves and X-rays, and that each observation of a supernovae remnant can give us different information about it. The site also includes a student exercise and links to more information.

302

EVOLUTION OF POST-IMPACT REMNANT HELIUM STARS IN TYPE Ia SUPERNOVA REMNANTS WITHIN THE SINGLE-DEGENERATE SCENARIO  

SciTech Connect

The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate. Based on recent hydrodynamics simulations, non-degenerate companions in the single-degenerate scenario (SDS) should survive the supernova (SN) impact. One way to distinguish between the SDS and the double-degenerate scenario is to search for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique that combines multi-dimensional hydrodynamics simulations with one-dimensional stellar evolution simulations, we have examined the post-impact evolution of helium-rich binary companions in the SDS. It is found that these helium-rich PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase (L {approx} 10{sup 4} L{sub Sun }) about 10 yr after an SN explosion. Subsequently, they contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by releasing gravitational energy, persisting as sdO-like stars for several million years before evolving to the helium red-giant phase. We therefore predict that a luminous OB-like star should be detectable within {approx}30 yr after the SN explosion. Thereafter, it will shrink and become an sdO-like star in the central regions of SN Ia remnants within star-forming regions for SN Ia progenitors evolved via the helium-star channel in the SDS. These He PIRSs are predicted to be rapidly rotating (v{sub rot} {approx}> 50 km s{sup -1}) and to have high spatial velocities (v{sub linear} {approx}> 500 km s{sup -1}). Furthermore, if SN remnants have diffused away and are not recognizable at a later stage, He PIRSs could be an additional source of single sdO stars and/or hypervelocity stars.

Pan, Kuo-Chuan; Ricker, Paul M. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Taam, Ronald E., E-mail: kpan2@illinois.edu, E-mail: pmricker@illinois.edu, E-mail: r-taam@northwestern.edu [Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)

2013-08-10

303

Pulsar Astronomy ---2000 and Beyond ASP Conference Series, Vol. 3 \\Theta 10 8 , 1999  

E-print Network

Pulsar Astronomy --- 2000 and Beyond ASP Conference Series, Vol. 3 \\Theta 10 8 , 1999 M. Kramer, N. Wex, and R. Wielebinski, eds. Puzzling Pulsars and Supernova Remnants D.R. Lorimer Arecibo Observatory, University of Amsterdam Abstract. The fact that the majority of the youngest radio pulsars are surrounded

Lorimer, Dunc

304

A statistical study of 233 pulsar proper motions  

Microsoft Academic Search

We present and analyse a catalogue of 233 pulsars with proper motion\\u000ameasurements. The sample contains a wide variety of pulsars including recycled\\u000aobjects and those associated with globular clusters or supernova remnants.\\u000aAfter taking the most precise proper motions for those pulsars for which\\u000amultiple measurements are available, the majority of the proper motions (58%)\\u000aare derived from pulsar

G. Hobbs; D. R. Lorimer; A. G. Lyne; M. Kramer

2005-01-01

305

The bubble-like interior of the core-collapse supernova remnant Cassiopeia A  

NASA Astrophysics Data System (ADS)

The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of these catastrophic explosions remain uncertain, due partly to limited observational constraints on asymmetries deep inside the star. Here we present near-infrared observations of the young supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior unshocked ejecta. The remnants interior has a bubble-like morphology that smoothly connects to and helps explain the multiringed structures seen in the remnant's bright reverse-shocked main shell of expanding debris. This internal structure may originate from turbulent mixing processes that encouraged outwardly expanding plumes of radioactive 56Ni-rich ejecta. If this is true, substantial amounts of its decay product, 56Fe, may still reside in these interior cavities.

Milisavljevic, Dan; Fesen, Robert A.

2015-01-01

306

Pulsar spins from an instability in the accretion shock of supernovae  

Microsoft Academic Search

Rotation-powered radio pulsars are born with inferred initial rotation periods of order 300ms (some as short as 20ms) in core-collapse supernovae. In the traditional picture, this fast rotation is the result of conservation of angular momentum during the collapse of a rotating stellar core. This leads to the inevitable conclusion that pulsar spin is directly correlated with the rotation of

John M. Blondin; Anthony Mezzacappa

2007-01-01

307

Chandra Observations and Models of the Mixed Morphology Supernova Remnant W44: Global Trends  

NASA Technical Reports Server (NTRS)

We report on the Chandra observations of the archetypical mixed morphology (or thermal composite) supernova remnant, W44. As with other mixed morphology remnants, W44's projected center is bright in thermal X-rays. It has an obvious radio shell, but no discernable X-ray shell. In addition, X-ray bright knots dot W44's image. The spectral analysis of the Chandra data show that the remnant s hot, bright projected center is metal-rich and that the bright knots are regions of comparatively elevated elemental abundances. Neon is among the affected elements, suggesting that ejecta contributes to the abundance trends. Furthermore, some of the emitting iron atoms appear to be underionized with respect to the other ions, providing the first potential X-ray evidence for dust destruction in a supernova remnant. We use the Chandra data to test the following explanations for W44's X-ray bright center: 1.) entropy mixing due to bulk mixing or thermal conduction, 2.) evaporation of swept up clouds, and 3.) a metallicity gradient, possibly due to dust destruction and ejecta enrichment. In these tests, we assume that the remnant has evolved beyond the adiabatic evolutionary stage, which explains the X-ray dimness of the shell. The entropy mixed model spectrum was tested against the Chandra spectrum for the remnant's projected center and found to be a good match. The evaporating clouds model was constrained by the finding that the ionization parameters of the bright knots are similar to those of the surrounding regions. While both the entropy mixed and the evaporating clouds models are known to predict centrally bright X-ray morphologies, their predictions fall short of the observed brightness gradient. The resulting brightness gap can be largely filled in by emission from the extra metals in and near the remnant's projected center. The preponderance of evidence (including that drawn from other studies) suggests that W44's remarkable morphology can be attributed to dust destruction and ejecta enrichment within an entropy mixed, adiabatic phase supernova remnant. The Chandra data prompts a new question - by what astrophysical mechanisms are the metals distributed so inhomogeneously in the supernova remnant.

Shelton, R. L.; Kuntz, K. D.; Petre, R.

2004-01-01

308

Uncovering the Properties of Young Neutron Stars and their Surrounding Supernova Remnants  

NASA Technical Reports Server (NTRS)

This five-year grant involves the study of young neutron stars, particularly those in supernova remnants.In the fourth year of this program, the following studies have been undertaken in support of this effort: 1.CTA 1: Following up on our ROSAT and ASCA studies of this SNR, we obtained observations with the XMM-Newton observatory to investigate the central compact source and surrounding nebula. 2. 3C 58: Based upon our earlier Chandra observations, we submitted a successful Chandra Large Project proposal for a 350 ks observation of this young neutron star and its wind nebula. 3. G347.3 - - 0.5: Our Chandra observations of portions of this SNR were aimed at studying the nonthermal X-ray emission from the remnant shell. 4. Chandra Survey for Compact Objects in Supernova Remnants: We have formed a collaboration to carry out an extensive search for young neutron stars in nearby supernova remnants. Using X-ray observations from an approved Chandra Large Project, as well as from additional approved XMM observations, we are investigating a volume-limited sample of SNRs for which there is currently no evidence of associated neutron stars.

Oliversen, Ronald J. (Technical Monitor); Slane, Patrick O.

2004-01-01

309

Investigation of the Progenitors of the Type Ia Supernovae Associated with the LMC Supernova Remnants 0505-67.9 and 0509-68.7  

NASA Astrophysics Data System (ADS)

Although Type Ia supernovae have been heavily scrutinized due to their use in making cosmological distance estimates, we are still unable to definitively identify the progenitors for the entire population. While answers have been presented for certain specific systems, a complete solution remains elusive. We present observations of two supernova remnants (SNRs) in the Large Magellanic Cloud, SNR 0505-67.9 and SNR 0509-68.7, for which we have identified the center of the remnant and the 99.73% containment central region in which any companion star left over after the supernova must be located. Both remnants have a number of potential ex-companion stars near their centers; all possible single and double degenerate progenitor models remain viable for these two supernovae. Future observations may be able to identify the true ex-companions for both remnants.

Pagnotta, Ashley; Schaefer, Bradley E.

2015-01-01

310

Investigation of the Progenitors of the Type Ia Supernovae Associated With the LMC Supernova Remnants 0505-67.9 and 0509-68.7  

E-print Network

Although Type Ia supernovae have been heavily scrutinized due to their use in making cosmological distance estimates, we are still unable to definitively identify the progenitors for the entire population. While answers have been presented for certain specific systems, a complete solution remains elusive. We present observations of two supernova remnants (SNRs) in the Large Magellanic Cloud, SNR 0505-67.9 and SNR 0509-68.7, for which we have identified the center of the remnant and the 99.73% containment central region in which any companion star left over after the supernova must be located. Both remnants have a number of potential ex-companion stars near their centers; all possible single and double degenerate progenitor models remain viable for these two supernovae. Future observations may be able to identify the true ex-companions for both remnants.

Pagnotta, Ashley

2015-01-01

311

The Vela Pulsar and Its Synchrotron Nebula  

Microsoft Academic Search

We present high-resolution Chandra X-ray observations of PSR0833-45, the 89 ms pulsar associated with the Vela supernova remnant. We have acquired two observations of the pulsar separated by one month to search for morphological changes in the pulsar and its environment following an extreme glitch in its rotation frequency. We find a well-resolved nebula with a morphology remarkably similar to

D. J. Helfand; E. V. Gotthelf; J. P. Halpern

2000-01-01

312

Optical and Far-Ultraviolet Spectroscopy of Knot D in the Vela Supernova Remnant  

NASA Astrophysics Data System (ADS)

We present spectra of optical filaments associated with the X-ray knot D in the Vela supernova remnant. It has been suggested that knot D is formed by a bullet of supernova ejecta, that it is a breakout of the shock front of the Vela supernova remnant, and also that it is an outflow from the recently discovered remnant RX J0852.0-4622. We find that knot D is a bow shock propagating into an interstellar cloud with normal abundances and typical cloud densities (nH~4-11 cm-3). Optical long-slit spectra show that the [S II] ??6716, 6731 to H? line ratio is greater than unity, proving that the optical filaments are shock excited. The analysis of far-ultraviolet spectra obtained with the Hopkins Ultraviolet Telescope and with the Far Ultraviolet Spectroscopic Explorer (FUSE) LWRS aperture show that slower shocks (~100 km s-1) produce most of the low-ionization lines such as O III] ?1662, while faster shocks (~180 km s-1) produce the O VI ??1032, 1038 and other high-ionization lines. C III and O VI lines are also detected in the FUSE MDRS aperture, which was located on an X-ray-bright region away from the optical filaments. The lines have two velocity components consistent with ~150 km s-1 shocks on the near and far sides of the knot. The driving pressure in the X-ray knot, P/kB~1.8107 cm-3 K, is derived from the shock properties. This is over an order of magnitude larger than the characteristic X-ray pressure in the Vela supernova remnant. The velocity distribution of the emission and the overpressure support the idea that knot D is a bow shock around a bullet or cloud that originated near the center of the Vela remnant.

Sankrit, Ravi; Blair, William P.; Raymond, John C.

2003-05-01

313

Swift/BAT Detection of Hard X-Rays from Tycho's Supernova Remnant: Evidence for Titanium-44  

NASA Astrophysics Data System (ADS)

We report Swift/Burst Alert Telescope survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10?) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.

Troja, E.; Segreto, A.; La Parola, V.; Hartmann, D.; Baumgartner, W.; Markwardt, C.; Barthelmy, S.; Cusumano, G.; Gehrels, N.

2014-12-01

314

Toward an Empirical Theory of Pulsar Emission XI. Understanding the Orientations of Pulsar Radiation and Supernova "Kicks"  

E-print Network

Two entwined problems have remained unresolved since pulsars were discovered nearly 50 years ago: the orientation of their polarized emission relative to the emitting magnetic field and the direction of putative supernova ``kicks' relative to their rotation axes. The rotational orientation of most pulsars can be inferred only from the (``fiducial') polarization angle of their radiation, when their beam points directly at the Earth and the emitting polar fluxtube field is $\\parallel$ to the rotation axis. Earlier studies have been unrevealing owing to the admixture of different types of radiation (core and conal, two polarization modes), producing both $\\parallel$ or $\\perp$ alignments. In this paper we analyze the some 50 pulsars having three characteristics: core radiation beams, reliable absolute polarimetry, and accurate proper motions. The ``fiducial' polarization angle of the core emission, we then find, is usually oriented $\\perp$ to the proper-motion direction on the sky. As the primary core emission i...

Rankin, Joanna M

2015-01-01

315

Imagine the Universe: Radioactive Decay in Supernova Remnants  

NSDL National Science Digital Library

This site explains how supernovae can be detected and studied by measuring the decay of radioactive elements in the material ejected from them. It is part of the Goddard Space Flight Center's "Imagine the Universe" website, created by GSFC's Laboratory for High Energy Astrophysics. It includes text, remotely sensed imagery, and links to other topics related to high energy astrophysics.

316

Fast pulsars, strange stars  

SciTech Connect

The initial motivation for this work was the reported discovery in January 1989 of a 1/2 millisecond pulsar in the remnant of the spectacular supernova, 1987A. The status of this discovery has come into grave doubt as of data taken by the same group in February, 1990. At this time we must consider that the millisecond signal does not belong to the pulsar. The existence of a neutron star in remnant of the supernova is suspected because of recent observations on the light curve of the remnant, and of course by the neutrino burst that announced the supernova. However its frequency is unknown. I can make a strong case that a pulsar rotation period of about 1 ms divides those that can be understood quite comfortably as neutron stars, and those that cannot. What we will soon learn is whether there is an invisible boundary below which pulsar periods do not fall, in which case, all are presumable neutron stars, or whether there exist sub- millisecond pulsars, which almost certainly cannot be neutron stars. Their most plausible structure is that of a self-bound star, a strange-quark-matter star. The existence of such stars would imply that the ground state of the strong interaction is not, as we usually assume, hadronic matter, but rather strange quark matter. Let us look respectively at stars that are bound only by gravity, and hypothetical stars that are self-bound, for which gravity is so to speak, icing on the cake.

Glendenning, N.K.

1990-02-01

317

Five Years in the Mid-Infrared Development of the SN 1987A Supernova Remnant  

NASA Technical Reports Server (NTRS)

Spitzer has been used to monitor the mid-IR evolution of SN 1987A over a 5 year period as it develops into a supernova remnant through interaction with its surrounding environment. This interaction is dominated by the collision of the ejecta with the pre-existing equatorial ring. The mid-IR continuum indicates an increasing mass of shock-heated silicate dust, but without any significant change in temperature of the dust grains. Comparison of the IR and X-ray evolution of the remnant can be used to infer plasma conditions and the processing of the dust in the shock-heated X-ray emitting gas.

Dwek, Eliahu

2009-01-01

318

Anisotropic Thermal Conduction in Supernova Remnants: Relevance to Hot Gas Filling Factors in the Magnetized ISM  

E-print Network

We explore the importance of anisotropic thermal conduction in the evolution of supernova remnants via numerical simulations. The mean temperature of the bubble of hot gas is decreased by a factor of ~3 compared to simulations without thermal conduction, together with an increase in the mean density of hot gas by a similar factor. Thus, thermal conduction greatly reduces the volume of hot gas produced over the life of the remnant. This underscores the importance of thermal conduction in estimating the hot gas filling fraction and emissivities in high-stage ions in Galactic and proto-galactic ISMs.

David A. Tilley; Dinshaw S. Balsara

2006-04-05

319

The Progenitor of the New COMPTEL/ROSAT Supernova Remnant in Vela  

E-print Network

We show that (1) the newly discovered supernova remnant (SNR), GRO J0852--4642/RX J0852.0--4622, was created by a core-collapse supernova of a massive star, and (2) the same supernova event which produced the $^{44}$Ti detected by COMPTEL from this source is probably also responsible for a large fraction of the observed $^{26}$Al emission in the Vela region detected by the same instrument. The first conclusion is based on the fact that the remnant is currently expanding too slowly given its young age for it to be caused by a Type Ia supernova. If the current SNR shell expansion speed is greater than 3000 km/s, a $15 M_\\odot$ Type II supernova with a moderate kinetic energy exploding at about 150 pc away is favored. If the SNR expansion speed is lower than 2000 km s$^{-1}$, as derived naively from the X-ray data, a much more energetic supernova is required to have occurred at $\\sim250$ pc away in a dense environment at the edge of the Gum nebula. This progenitor has a preferred ejecta mass of $\\le10 M_\\odot$ and therefore, it is probably a Type Ib or Type Ic supernova. However, the required high ambient density of $n_H \\ge 100 cm^{-3}$ in this scenario is difficult to reconcile with the regional CO data. A combination of our estimates of the age/energetics of the new SNR and the almost perfect positional coincidence of the new SNR with the centroid of the COMPTEL $ ^{26}$Al emission feature of the Vela region strongly favors a causal connection. If confirmed, this will be the first case where both $^{44}$Ti and $^{26}$Al are detected from the same young SNR and together they can be used to select preferred theoretical core-collapse supernova models.

Wan Chen; Neil Gehrels

1999-02-24

320

THE GALACTIC SUPERNOVA REMNANT W49B LIKELY ORIGINATES FROM A JET-DRIVEN, CORE-COLLAPSE EXPLOSION  

E-print Network

We present results from a 220 ks observation of the Galactic supernova remnant (SNR) W49B using the Advanced CCD Imaging Spectrometer on board the Chanrda X-ray Observatory. We exploit these data to perform detailed spatially ...

Lopez, Laura A.

321

A CR-HYDRO-NEI MODEL OF THE STRUCTURE AND BROADBAND EMISSION FROM TYCHOS SUPERNOVA REMNANT  

E-print Network

Tycho's supernova remnant (SNR) is well-established as a source of particle acceleration to very high energies. Constraints from numerous studies indicate that the observed ?-ray emission results primarily from hadronic ...

Slane, P.

322

MOLECULAR ENVIRONMENT AND THERMAL X-RAY SPECTROSCOPY OF THE SEMICIRCULAR YOUNG COMPOSITE SUPERNOVA REMNANT 3C 396  

E-print Network

We have investigated the molecular environment of the semicircular composite supernova remnant (SNR) 3C 396 and performed a Chandra spatially resolved thermal X-ray spectroscopic study of this young SNR. With our CO ...

Su, Yang

323

Pulsar Kicks from Active-Sterile Neutrino Transformation in Supernovae  

E-print Network

Observations of radio pulsars have revealed that they have large velocities which may be greater than 1000 km/s. In this work, the efficacy of an active-sterile neutrino transformation mechanism to provide these large pulsar kicks is investigated. A phase-space based approach is adopted to follow the the transformation of active neutrinos to sterile neutrinos through an MSW-like resonance in the protoneutron star to refine an estimate to the magnitude of the pulsar kick that can be generated in such an event. The result is that this mechanism can create the large pulsar kicks that are observed while not overcooling the star.

Chad T. Kishimoto

2011-06-17

324

Discovery of TeV Gamma Rays from SN 1006: Further Evidence for the Supernova Remnant Origin of Cosmic Rays  

Microsoft Academic Search

In this Letter we report the discovery of TeV gamma-ray emission from a supernova remnant made with the CANGAROO 3.8 m telescope. TeV gamma rays were detected at the sky position and extension coincident with the northeast rim of shell-type supernova remnant (SNR) SN 1006 (Type Ia). SN 1006 has been a most likely candidate for an extended TeV gamma-ray

T. Tanimori; Y. Hayami; S. Kamei; S. A. Dazeley; P. G. Edwards; S. Gunji; S. Hara; T. Hara; J. Holder; A. Kawachi; T. Kifune; R. Kita; T. Konishi; A. Masaike; Y. Matsubara; T. Matsuoka; Y. Mizumoto; M. Mori; M. Moriya; H. Muraishi; Y. Muraki; T. Naito; K. Nishijima; S. Oda; S. Ogio; J. R. Patterson; M. D. Roberts; G. P. Rowell; K. Sakurazawa; T. Sako; Y. Sato; R. Susukita; A. Suzuki; R. Suzuki; T. Tamura; G. J. Thornton; S. Yanagita; T. Yoshida; T. Yoshikoshi

1998-01-01

325

The Nature of the Compact X-ray Source in Supernova Remnant RCW 103  

E-print Network

The discovery of the 6.67 hr periodicity in the X-ray source 1E 161348-5055 associated with the supernova remnant RCW 103 has raised interesting suggestions about the nature of the X-ray source. Here we argue that in either accreting neutron star or magnetar model, a supernova fallback disk may be a critical ingredient in theoretical interpretations of 1E 161348-5055. We further emphasize the effect of fallback disks on the evolution of young compact objects in various ways, and suggest that even SS 433 could also be powered by fallback disk accretion process.

Xiang-Dong Li

2007-08-01

326

XMM-Newton Observations of HESSJ1813-178 Reveal a Composite Supernova Remnant  

SciTech Connect

Aims--We present X-ray and {sup 12}CO(J=1-0) observations of the very-high-energy (VHE) {gamma}-ray source HESS J1813-178 with the aim of understanding the origin of the {gamma}-ray emission. Methods--High-angular resolution X-ray studies of the VHE {gamma}-ray emission region are performed using 18.6 ks of XMM-Newton data, taken on HESS J1813-178 in October 2005. Using this dataset we are able to undertake spectral and morphological studies of the X-ray emission object with greater precision than previous studies. NANTEN {sup 12}CO(J=1-0) data are used to search for correlations of the {gamma}-ray emission with molecular clouds which could act as target material for {gamma}-ray production in a hadronic scenario. Results--The NANTEN {sup 12}CO(J=1-0) observations show a giant molecular cloud of mass 2.5 x 10{sup 5} M{sub {circle_dot}} at a distance of 4 kpc in the vicinity of HESS J1813-178. Even though there is no direct positional coincidence, this giant cloud might have influenced the evolution of the {gamma}-ray source and its surroundings. The X-ray data show a highly absorbed (n{sub H} {approx} 1 x 10{sup 23} cm{sup -2}) non-thermal X-ray emitting object coincident with the previously known ASCA source AXJ1813-178 showing a compact core and an extended tail towards the north-east, located in the center of the radio shell-type Supernova remnant (SNR) G12.82-0.2. This central object shows morphological and spectral resemblance to a Pulsar Wind Nebula (PWN) and we therefore consider that this object is very likely to be a composite SNR. Nevertheless, we cannot distinguish between the scenarios in which the {gamma}-rays originate in the shell of the SNR and the one in which they originate in the central object. We discuss both scenarios in terms of a one-zone leptonic model and demonstrate, that in order to connect the core X-ray emission to the VHE {gamma}-ray emission electrons have to be accelerated to energies of at least 1 PeV. We conclude that if indeed the X-rays are connected to the VHE {gamma}-rays HESS J1813-178 has to be a Galactic Pevatron.

Funk, S.; Hinton, J.A.; Moriguchi, Y.; Aharonian, F.A.; Fukui, Y.; Hofmann, W.; Horns, D.; Puehlhofer, G.; Reimer, O.; Rowell, G.; Terrier, R.; Vink, J.; Wagner, S.

2006-11-27

327

ASCA Observations of the Thermal Composite Supernova Remnant 3C 391  

E-print Network

We present the results from ASCA observations of the centrally enhanced supernova remnant 3C 391 (G31.9+0.0). We use the ASCA SIS data to carry out an investigation of the spatial and spectral properties of the X-ray emission from this remnant. The collisional equilibrium ionization and non-equilibrium ionization spectral fits indicate that the hot gas within the remnant has basically reached ionization equilibrium. The variation of the hydrogen column density across the remnant is in agreement with the presence of a molecular cloud to the northwest. The comparisons of hydrogen column and X-ray hardness between the NW and SE portions of the remnant support a scenario in which the SNR has broken out of a dense region into an adjacent region of lower density. The mean density within the SNR is observed to be much lower than the immediate ambient cloud density. This and the centrally brightened X-ray morphology can be explained either by the evaporation of engulfed cloudlets or by a radiative stage of evolution for the remnant.

Yang Chen; Patrick Slane

2001-08-31

328

X-RAY EMISSION FROM STRONGLY ASYMMETRIC CIRCUMSTELLAR MATERIAL IN THE REMNANT OF KEPLER'S SUPERNOVA  

SciTech Connect

Kepler's supernova remnant resulted from a thermonuclear explosion, but is interacting with circumstellar material (CSM) lost from the progenitor system. We describe a statistical technique for isolating X-ray emission due to CSM from that due to shocked ejecta. Shocked CSM coincides well in position with 24 {mu}m emission seen by Spitzer. We find most CSM to be distributed along the bright north rim, but substantial concentrations are also found projected against the center of the remnant, roughly along a diameter with position angle {approx}100 Degree-Sign . We interpret this as evidence for a disk distribution of CSM before the supernova, with the line of sight to the observer roughly in the disk plane. We present two-dimensional hydrodynamic simulations of this scenario in qualitative agreement with the observed CSM morphology. Our observations require Kepler to have originated in a close binary system with an asymptotic giant branch star companion.

Burkey, Mary T.; Reynolds, Stephen P.; Borkowski, Kazimierz J.; Blondin, John M., E-mail: reynolds@ncsu.edu [Department of Physics, North Carolina State University, Raleigh NC 27695-8202 (United States)

2013-02-10

329

Onion-shell model of cosmic ray acceleration in supernova remnants  

NASA Technical Reports Server (NTRS)

A method is devised to approximate the spatially averaged momentum distribution function for the accelerated particles at the end of the active lifetime of a supernova remnant. The analysis is confined to the test particle approximation and adiabatic losses are oversimplified, but unsteady shock motion, evolving shock strength, and non-uniform gas flow effects on the accelerated particle spectrum are included. Monoenergetic protons are injected at the shock front. It is found that the dominant effect on the resultant accelerated particle spectrum is a changing spectral index with shock strength. High energy particles are produced in early phases, and the resultant distribution function is a slowly varying power law over several orders of magnitude, independent of the specific details of the supernova remnant.

Bogdan, T. J.; Volk, H. J.

1983-01-01

330

The supernova remnant W51C: a plausible source of galactic cosmic rays?  

NASA Astrophysics Data System (ADS)

Supernova remnants are a probable site of acceleration of particles via diffusive shock processes. High energies carried by electrons or protons are radiated into photons detectable from radio to ? rays. MAGIC has recently observed W51C, one of the most luminous galactic supernova remnants, and completed its spectrum between 50 GeV and 5 TeV. We modelled different processes for high energy photon emission of this source, and compared the predictions with the measured spectral energy distribution. It is plausible that hadrons are accelerated in the expansion front of this source, in interaction with the surrounding molecular cloud, and photons are produced in the decay of neutral mesons created in hadronic collisions.

Gozzini, S. R.; Carmona, E.; Jankowski, F.; Krause, J.; Reichardt, I.; MAGIC Collaboration

2013-02-01

331

Multi-dimensional Simulations of the Expanding Supernova Remnant of SN 1987A  

NASA Astrophysics Data System (ADS)

The expanding remnant from SN 1987A is an excellent laboratory for investigating the physics of supernovae explosions. There is still a large number of outstanding questions, such as the reason for the asymmetric radio morphology, the structure of the pre-supernova environment, and the efficiency of particle acceleration at the supernova shock. We explore these questions using three-dimensional simulations of the expanding remnant between days 820 and 10,000 after the supernova. We combine a hydrodynamical simulation with semi-analytic treatments of diffusive shock acceleration and magnetic field amplification to derive radio emission as part of an inverse problem. Simulations show that an asymmetric explosion, combined with magnetic field amplification at the expanding shock, is able to replicate the persistent one-sided radio morphology of the remnant. We use an asymmetric Truelove & McKee progenitor with an envelope mass of 10 M ? and an energy of 1.5 1044 J. A termination shock in the progenitor's stellar wind at a distance of 0.''43-0.''51 provides a good fit to the turn on of radio emission around day 1200. For the H II region, a minimum distance of 0.''63 0.''01 and maximum particle number density of (7.11 1.78) 107 m-3 produces a good fit to the evolving average radius and velocity of the expanding shocks from day 2000 to day 7000 after explosion. The model predicts a noticeable reduction, and possibly a temporary reversal, in the asymmetric radio morphology of the remnant after day 7000, when the forward shock left the eastern lobe of the equatorial ring.

Potter, T. M.; Staveley-Smith, L.; Reville, B.; Ng, C.-Y.; Bicknell, G. V.; Sutherland, R. S.; Wagner, A. Y.

2014-10-01

332

The Most Likely Sources of High-Energy Cosmic-Ray Electrons in Supernova Remnants  

Microsoft Academic Search

Evidence of nonthermal X-ray emission and TeV gamma rays from supernova remnants (SNRs) have strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High-energy electrons lose energy via synchrotron and inverse Compton processes during propagation in the Galaxy. Because of these radiative losses, TeV electrons liberated from SNRs at distances larger than ~1 kpc, or times older

T. Kobayashi; Y. Komori; K. Yoshida; J. Nishimura

2004-01-01

333

The Emerging Picture of Supernova Remnants and GRBs at High Energies  

NASA Astrophysics Data System (ADS)

In the last two years, high-energy studies of supernova remnants (SNRs) and gamma-ray bursts (GRBs) have yielded many new insights regarding the nature of explosions and their environments. In this talk, I will highlight several recent advances in these fields catalyzed by high energy theory and observations, with emphasis on progenitor systems, nucleosynthesis, and particle acceleration. Finally, I will discuss anticipated advances with upcoming facilities, like Astro-H and Advanced LIGO.

Lopez, Laura A.

2014-08-01

334

Revealing the hitherto hidden X-ray emission from shell-type supernova remnant Kes 32  

Microsoft Academic Search

I will show results from Chandra ACIS-I observations of Kes 32 (G332.+0.1). A supernova remnant of 8arcmin size, that has never been imaged in X-rays before, largely as it was too obscured at low energies, and is situated in a complex region of the galaxy. Chandra reveals that the X-ray morphology is similar to the radio morphology, although the shell

J. Vink

2003-01-01

335

In my Beginning is my End: Dust Destruction in the Cassiopeia A Supernova Remnant  

NASA Astrophysics Data System (ADS)

It has been demonstrated by observations that young supernovae (SNe) are indeed able to efficiently synthesize dust. However, it is unclear how much of the freshly formed dust can reach the interstellar medium and contribute to the observed emission. At the same time, SNe represent the major agent responsible for dust destruction. Because SNe are possibly the only viable dust factory in the early Universe, it is extremely important to establish the fate of the newly formed dust. Our work explores the possibility that a significant fraction of any dust formed after the explosion is destroyed within the supernova remnant itself. In the Cassiopeia A supernova remnant, dust emission has been observed associated with optical knots containing recently formed material. The dust present in such clumps is threatened by the reverse shock traveling through the ejecta toward the center of the remnant. The shock is able to disrupt the clumps and will inject the dust grains into a hot gas, where they will be eroded and possibly destroyed by thermal and inertial sputtering. We present a model that describes the propagation of the reverse shock into the supernova cavity and evaluates the modifications in the grain size distribution due to the encounter with the reverse shock. This is the first step required to quantify the amount of dust ultimately able to survive. Our model accounts for the variation of the physical properties of both the shock and the ejecta across the remnant. In particular, this means taking explicitly into consideration, for the first time in this kind of studies, the effect of clumping of the ejecta.

Micelotta, E.; Dwek, E.

336

MODIFIED EQUIPARTITION CALCULATION FOR SUPERNOVA REMNANTS. CASES ? = 0.5 AND ? = 1  

SciTech Connect

The equipartition or minimum energy calculation is a well-known procedure for estimating the magnetic field strength and the total energy in the magnetic field and cosmic ray particles by using only the radio synchrotron emission. In one of our previous papers, we have offered a modified equipartition calculation for supernova remnants (SNRs) with spectral indices 0.5 < ? < 1. Here we extend the analysis to SNRs with ? = 0.5 and ? = 1.

Arbutina, B.; Uroevi?, D.; Vu?eti?, M. M.; Pavlovi?, M. Z. [Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 11000 Belgrade (Serbia); Vukoti?, B., E-mail: arbo@math.rs [Astronomical Observatory, Volgina 7, 11060 Belgrade 38 (Serbia)

2013-11-01

337

G306.3-0.9: A NEWLY DISCOVERED YOUNG GALACTIC SUPERNOVA REMNANT  

SciTech Connect

We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of {approx}160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24 {mu}m, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

Reynolds, Mark T.; Miller, Jon M.; Maitra, Dipankar; Gueltekin, Kayhan; Reis, Rubens C. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)] [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Loi, Shyeh T.; Murphy, Tara; Moss, Vanessa; Reeves, Sarah; Robbins, William J.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia)] [Sydney Institute for Astronomy (SIfA), School of Physics, The University of Sydney, NSW 2006 (Australia); Gehrels, Neil; Petre, Robert [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)] [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kennea, Jamie A.; Siegel, Michael H.; Gelbord, Jonathan [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Kuin, Paul, E-mail: markrey@umich.edu [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)] [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom)

2013-04-01

338

Diffuse neutrinos from extragalactic supernova remnants: Dominating the 100 TeV IceCube flux  

E-print Network

IceCube has measured a diffuse astrophysical flux of TeV-PeV neutrinos. The most plausible sources are unique high energy cosmic ray accelerators like hypernova remnants (HNRs) and remnants from gamma ray bursts in star-burst galaxies, which can produce primary cosmic rays with the required energies and abundance. In this case, however, ordinary supernova remnants (SNRs), which are far more abundant than HNRs, produce a comparable or larger neutrino flux in the ranges up to 100-150 TeV energies, implying a spectral break in the IceCube signal around these energies. The SNRs contribution in the diffuse flux up to these hundred TeV energies provides a natural baseline and then constrains the expected PeV flux.

Chakraborty, Sovan

2015-01-01

339

G306.3-0.9: A Newly Discovered Young Galactic Supernova Remnant  

NASA Technical Reports Server (NTRS)

We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of 160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24m, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

Reynolds, Mark T.; Loi, Syheh T.; Murphy, Tara; Miller, Jon M.; Maitra, Dipankar; Gueltekin, Kayhan; Gehrels, Neil; Kennea, Jamie A.; Siegel, Michael H.; Gelbord, Jonathan; Kuin, Paul; Moss, Vanessa; Reeves, Sarah; Robbins, William J.; Gaensler, B. M.; Reis, Rubens C.; Petre, Robert

2013-01-01

340

The Bubble-like Interior of the Core-Collapse Supernova Remnant Cassiopeia A  

E-print Network

The death of massive stars is believed to involve aspheric explosions initiated by the collapse of an iron core. The specifics of how these catastrophic explosions proceed remain uncertain due, in part, to limited observational constraints on various processes that can introduce asymmetries deep inside the star. Here we present near-infrared observations of the young Milky Way supernova remnant Cassiopeia A, descendant of a type IIb core-collapse explosion, and a three-dimensional map of its interior, unshocked ejecta. The remnant's interior has a bubble-like morphology that smoothly connects to and helps explain the multi-ringed structures seen in the remnant's bright reverse shocked main shell of expanding debris. This internal structure may have originated from turbulent mixing processes that encouraged the development of outwardly expanding plumes of radioactive 56Ni-rich ejecta. If this is true, substantial amounts of its decay product, 56Fe, may still reside in these interior cavities.

Milisavljevic, Dan

2015-01-01

341

THE {sup 7}Li/{sup 6}Li ISOTOPE RATIO NEAR THE SUPERNOVA REMNANT IC 443  

SciTech Connect

We present an analysis of {sup 7}Li/{sup 6}Li isotope ratios along four sight lines that probe diffuse molecular gas near the supernova remnant IC 443. Recent gamma-ray observations have revealed the presence of shock-accelerated cosmic rays interacting with the molecular cloud surrounding the remnant. Our results indicate that the {sup 7}Li/{sup 6}Li ratio is lower in regions more strongly affected by these interactions, a sign of recent Li production by cosmic rays. We find that {sup 7}Li/{sup 6}Li Almost-Equal-To 7 toward HD 254755, which is located just outside the visible edge of IC 443, while {sup 7}Li/{sup 6}Li Almost-Equal-To 3 along the line of sight to HD 43582, which probes the interior region of the supernova remnant. No evidence of {sup 7}Li synthesis by neutrino-induced spallation is found in material presumably contaminated by the ejecta of a core-collapse supernova. The lack of a neutrino signature in the {sup 7}Li/{sup 6}Li ratios near IC 443 is consistent with recent models of Galactic chemical evolution, which suggest that the {nu}-process plays only a minor role in Li production.

Taylor, C. J.; Ritchey, A. M.; Federman, S. R. [Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States); Lambert, D. L., E-mail: corbin.taylor@rockets.utoledo.edu, E-mail: steven.federman@utoledo.edu, E-mail: aritchey@astro.washington.edu, E-mail: dll@astro.as.utexas.edu [W. J. McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States)

2012-05-01

342

High-resolution IUE observations of interstellar absorption lines in the Vela supernova remnant  

NASA Technical Reports Server (NTRS)

Ultraviolet spectra of 45 stars in the vicinity of the Vela supernova remnant were recorded by the short-wavelength echelle spectrograph aboard the International Ultraviolet Explorer (IUE). Over one-third of the stars show interstellar absorption lines at large radial velocities (greater than 60 km/s). The mapping of these high-velocity components in the sky suggests the motions are chaotic, rather than from a coherent expansion of the remnant material. In accord with earlier conclusions from Copernicus data, the gas at high velocity exhibits higher than normal ionization and shows substantially less depletion of nonvolatile elements than normal interstellar material at low velocities. Relatively strong lines from neutral carbon in the two excited fine-structure states indicate that the neutral clouds within the remnant have had their pressures enhanced by the passage of the blast wave from the supernova. Also, the remnant seems to show a significant enhancement in the abundances of low-velocity Si IV, C IV, and N V over those found in the general interstellar medium.

Jenkins, E. B.; Wallerstein, G.; Silk, J.

1984-01-01

343

Using Poisson statistics to analyze supernova remnant emission in the low counts X-ray regime  

NASA Astrophysics Data System (ADS)

We utilize a Poisson likelihood in a maximum likelihood statistical analysis to analyze X-ray spectragraphic data. Specifically, we examine four extragalactic supernova remnants (SNR). IKT 5 (SNR 0047-73.5), IKT 25 (SNR 0104-72.3), and DEM S 128 (SNR 0103-72.4) which are designated as Type Ia in the literature due to their spectra and morphology. This is troublesome because of their asymmetry, a trait not usually associated with young Type Ia remnants. We present Chandra X-ray Observatory data on these three remnants, and perform a maximum likelihood analysis on their spectra. We find that the X-ray emission is dominated by interactions with the interstellar medium. In spite of this, we find a significant Fe overabundance in all three remnants. Through examination of radio, optical, and infrared data, we conclude that these three remnants are likely not "classical" Type Ia SNR, but may be examples of so-called "prompt" Type Ia SNR. We detect potential point sources that may be members of the progenitor systems of both DEM S 128 and IKT 5, which could suggest a new subclass of prompt Type Ia SNR, Fe-rich CC remnants. In addition, we examine IKT 18. This remnant is positionally coincident with the X-ray point source HD 5980. Due to an outburst in 1994, in which its brightness changed by 3 magnitudes (corrsponding to an increase in luminosity by a factor of 16) HD 5980 was classified as a luminous blue variable star. We examine this point source and the remnant IKT 18 in the X-ray, and find that its non-thermal photon index has decreased from 2002 to 2013, corresponding to a larger proportion of more energetic X-rays, which is unexpected.

Roper, Quentin Jeffrey

344

GMRT observations of four suspected supernova remnants near the Galactic Centre  

E-print Network

We have observed two fields - Field-I (l=3.2 degrees, b=-1.0 degree) and Field-II (l=356.8 degrees, b=-0.1 degree) with the Giant Metrewave Radio Telescope (GMRT) at 330 MHz. In the first field, we have studied the candidate supernova remnant (SNR) G3.1-0.6 and based on its observed morphology, spectral index and polarisation confirmed it to be an SNR. We find this supernova to have a double ring appearance with a strip of emission on it's western side passing through it's centre. We have discovered two extended curved objects in the second field, which appears to be part of a large shell like structure. It is possibly the remains of an old supernova in the region. Three suspected supernova remnants, G356.3-0.3, G356.6+0.1 and G357.1-0.2 detected in the MOST 843 MHz survey of the Galactic Centre region appears to be located on this shell like structure. While both G356.3-0.3 and G356.6+0.1 seem to be parts of this shell, G357.1-0.2 which has a steeper spectrum above 1 GHz, could be a background SNR seen through the region. Our HI absorption observation towards the candidate SNR G357.1-0.2 indicates that it is at a distance of more than 6 kpc from us.

Subhashis Roy; A. Pramesh Rao

2001-10-04

345

A Bow Shock Nebula around a Compact X-Ray Source in the Supernova Remnant IC 443  

NASA Astrophysics Data System (ADS)

We present Chandra spectra and high-resolution images of the hard X-ray feature in the southern edge of the supernova remnant (SNR) IC 443 that reveal a comet-shaped nebula of hard emission that contains a softer point source at its apex. We also present 20, 6, and 3.5 cm Very Large Array maps that clearly show the cometary nebula. Based on the radio and X-ray morphology and spectrum, and the radio polarization properties, we argue that this object is a synchrotron nebula powered by the compact source that is physically associated with IC 443. The spectrum of the soft point source is adequately but not uniquely fitted by a blackbody model [kT=0.71+/-0.08 keV, L=(6.5+/-0.9)1031 ergs s-1]. The morphology of the nebula can be explained by the supersonic motion of the neutron star (VNS~=250+/-50 km s-1), which causes the relativistic wind of the pulsar to terminate in a bow shock and trail behind as a synchrotron tail. This velocity is consistent with an age of 30,000 yr for the SNR and its associated neutron star.

Olbert, Charles M.; Clearfield, Christopher R.; Williams, Nikolas E.; Keohane, Jonathan W.; Frail, Dale A.

2001-06-01

346

Theory of cosmic-ray and ?-ray production in the supernova remnant RX J0852.04622 (Vela Jr.)  

NASA Astrophysics Data System (ADS)

Nearly ten years after the discovery of the supernova remnant RX J0852.0-4622 ("Vela Jr.") with ROSAT in 1998, many important parameters of the remnant are still largely uncertain. Distance estimates range between 200 pc and 1-2 kpc, with correspondingly different estimates on the time and type of the supernova explosion. We present the application of our kinetic theory of cosmic ray acceleration in supernova remnants to RX J0852.0-4622. We investigate whether the broadband non-thermal emission from this remnant - from radio to X-rays to TeV gamma-rays - can be understood, applying different scenarios for the supernova remnant evolution that are compatible with existing broadband data. In all cases we find that the remnant is an efficient hadronic accelerator and that the gamma-ray emission is therefore dominated by Pi0-decay. We discuss how the results can be used to put additional constraints on the remnant's distance and age.

Berezhko, E. G.; Phlhofer, G.; Vlk, H. J.

347

New Candidates for Supernova Remnants in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We propose observations of nine NEW candidates for SNRs in the LMC. These sources were detected in ROSAT data and classified as candidates for thermal SNRs based on their X-ray properties and radio counterparts. Using EPICs as the primary instruments we will detect emission lines of ionized atoms characteristic of thermal SNRs and determine the spatial extent. The high sensitivity of XMM-Newton will allow to detect SNRs that are X-ray faint either because of their age or the ambient medium and enlarge the sample of known SNRs to lower brightness levels. We will thus be able to construct a more complete X-ray luminosity function of SNRs in the LMC and will obtain information about typical abundances, densities, and initial supernova energies in the LMC.

Sasaki, Manami

2009-10-01

348

HFPK 334: An Unusual Supernova Remnant in the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We present new Australia Telescope Compact Array radio-continuum and XMM-Newton/Chandra X-ray Observatory observations of the unusual supernova remnant (SNR) HFPK 334 in the Small Magellanic Cloud (SMC). The remnant follows a shell-type morphology in the radio continuum and has a size of ~20 pc at the SMC distance. The X-ray morphology is similar; however, we detect a prominent point source close to the center of the SNR exhibiting a spectrum with a best-fit power law with a photon index of ? = 2.7 0.5. This central point source is most likely a background object and cannot be directly associated with the remnant. The high temperature, nonequilibrium conditions in the diffuse region suggest that this gas has been recently shocked and points toward a younger SNR with an age of <~ 1800 yr. With an average radio spectral index of ? = -0.59 0.09, we find that an equipartition magnetic field for the remnant is ~90 ?G, a value typical of younger SNRs in low-density environments. Also, we report the detection of scattered radio polarization across the remnant at 20 cm, with a peak fractional polarization level of 25% 5%.

Crawford, E. J.; Filipovi?, M. D.; McEntaffer, R. L.; Brantseg, T.; Heitritter, K.; Roper, Q.; Haberl, F.; Uroevi?, D.

2014-11-01

349

Pulsar spins from an instability in the accretion shock of supernovae  

E-print Network

Rotation-powered radio pulsars are born with inferred initial rotation periods of order 300 ms (some as short as 20 ms) in core-collapse supernovae. In the traditional picture, this fast rotation is the result of conservation of angular momentum during the collapse of a rotating stellar core. This leads to the inevitable conclusion that pulsar spin is directly correlated with the rotation of the progenitor star. So far, however, stellar theory has not been able to explain the distribution of pulsar spins, suggesting that the birth rotation is either too slow or too fast. Here we report a robust instability of the stalled accretion shock in core-collapse supernovae that is able to generate a strong rotational flow in the vicinity of the accreting proto-neutron star. Sufficient angular momentum is deposited on the proto-neutron star to generate a final spin period consistent with observations, even beginning with spherically symmetrical initial conditions. This provides a new mechanism for the generation of neutron star spin and weakens, if not breaks, the assumed correlation between the rotational periods of supernova progenitor cores and pulsar spin.

John M. Blondin; Anthony Mezzacappa

2006-11-21

350

Failed Supernovae Explain the Compact Remnant Mass Function  

NASA Astrophysics Data System (ADS)

One explanation for the absence of higher mass red supergiants (16.5 M ? <~ M <~ 25 M ?) as the progenitors of Type IIP supernovae (SNe) is that they die in failed SNe creating black holes. Simulations show that such failed SNe still eject their hydrogen envelopes in a weak transient, leaving a black hole with the mass of the star's helium core (5-8 M ?). Here we show that this naturally explains the typical masses of observed black holes and the gap between neutron star and black hole masses without any fine-tuning of stellar mass loss, binary mass transfer, or the SN mechanism, beyond having it fail in a mass range where many progenitor models have density structures that make the explosions more likely to fail. There is no difficulty including this ~20% population of failed SNe in any accounting of SN types over the progenitor mass function. And, other than patience, there is no observational barrier to either detecting these black hole formation events or limiting their rates to be well below this prediction.

Kochanek, C. S.

2014-04-01

351

Very high resolution calculations of very young supernova remnants  

SciTech Connect

After the supernova shock wave has swepted up about 8 to 10 stellar masses of interstellar material, the SNR structure is well described by blast wave theory. In fact, both numerical calculations of the early phases and small scale, laboratory simulations show transition to blast wave at 8 to 10 masses. In hindsight, we now know that the transition region between the photosphere (roughly 10/sup -9/ g/cm/sup 3/) and the circumstellar medium (10/sup -24/ g/cm/sup 3/) plays a crucial role. The shock wave is strongly accelerated down the density gradient, putting the shocked material behind into free expansion. When the shock encounters circumstellar material, it begins to decelerate. A second, reverse shock propagates into the stellar material that plows into the shocked circumstellar gas. All this happens on a timescale of days. The first attempts to include a description of the outer stellar envelop were aimed at analysis of the uv and X-Ray bursts produced when the shock wave reaches the photosphere. Falk and Arnett terminated their calculations before the shock reached the circumstellar gas. Chevalier mentions a reverse shock forming early but did not go into any details. We noticed and described the double-shock structure but, in hindsight, lacked sufficient resolution to produce the detailed structure between the shocks. Chevalier derived a similarity solution for the intershock region. In this paper we describe very high resolution calculations which reproduce and confirm the Chevalier similarity solution.

Jones, E.M.; Smith, B.W.

1982-01-01

352

Nature versus Nurture: The Origin of Soft Gamma-Ray Repeaters and Anomalous X-Ray Pulsars  

Microsoft Academic Search

Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are young and radio-quiet X-ray pulsars that have been rapidly spun-down to slow spin periods clustered in the range 5-12 s. Most of these unusual pulsars also appear to be associated with supernova shell remnants (SNRs) with typical ages less than 30 kyr. By examining the sizes of these remnants versus

D. Marsden; R. E. Lingenfelter; R. E. Rothschild; J. C. Higdon

2001-01-01

353

Four new X-ray-selected supernova remnants in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

Aims: We present a detailed multi-wavelength study of four new supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). The objects were identified as SNR candidates in X-ray observations performed during the survey of the LMC with XMM-Newton. Methods: Data obained with XMM-Newton are used to investigate the morphological and spectral features of the remnants in X-rays. We measure the plasma conditions, look for supernova (SN) ejecta emission, and constrain some of the SNR properties (e.g. age and ambient density). We supplement the X-ray data with optical, infrared, and radio-continuum archival observations, which allow us to understand the conditions resulting in the current appearance of the remnants. Based on the spatially-resolved star formation history (SFH) of the LMC together with the X-ray spectra, we attempt to type the supernovae that created the remnants. Results: We confirm all four objects as SNRs, to which we assign the names MCSNR J0508-6830, MCSNR J0511-6759, MCSNR J0514-6840, and MCSNR J0517-6759. In the first two remnants, an X-ray bright plasma is surrounded by very faint [S ii] emission. The emission from the central plasma is dominated by Fe L-shell lines, and the derived iron abundance is greatly in excess of solar. This establishes their type Ia (i.e. thermonuclear) SN origin. They appear to be more evolved versions of other Magellanic Cloud iron-rich SNRs which are centrally-peaked in X-rays. From the two other remnants (MCSNR J0514-6840 and MCSNR J0517-6759), we do not see ejecta emission. At all wavelengths at which they are detected, the local environment plays a key role in their observational appearance. We present evidence that MCSNR J0517-6759 is close to and interacting with a molecular cloud, suggesting a massive progenitor. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Maggi, P.; Haberl, F.; Kavanagh, P. J.; Points, S. D.; Dickel, J.; Bozzetto, L. M.; Sasaki, M.; Chu, Y.-H.; Gruendl, R. A.; Filipovi?, M. D.; Pietsch, W.

2014-01-01

354

Recoil of the Stellar Remnant from the Puppis A Supernova: Proper-Motion Measurement from Chandra  

NASA Technical Reports Server (NTRS)

A sequence of three Chandra X-ray Observatory High Resolution Camera images taken over a span of five years reveals arc-second-scale displacement of RX-J0822--4300, the stellar remnant near the center of the Puppis A supernova remnant. We measure its proper motion to be 0.16+/-0.02 arcsec/yr toward the west-southwest. At a distance of 2 kpc, this corresponds to a transverse space velocity of approx. 1500 km/s. This is the first case of a compact X-ray source with a directly measured proper motion. The space velocity is consistent with the explosion center inferred from proper motions of the oxygen-rich optical filaments, and confirms the idea that Puppis A resulted from an asymmetric explosion accompanied by a kick that imparted on the order of 3 x 10(exp 49) ergs of kinetic energy (some 3 percent of the supernova kinetic energy) to the stellar remnant. We will summarize this measurement and discuss possible mechanisms for producing such a violent kick. This research has been supported by NASA grant G04-5062X.

Petre, Robert; Winkler, P. F.

2006-01-01

355

EVIDENCE FOR PARTICLE ACCELERATION TO THE KNEE OF THE COSMIC RAY SPECTRUM IN TYCHO'S SUPERNOVA REMNANT  

SciTech Connect

Supernova remnants (SNRs) have long been assumed to be the source of cosmic rays (CRs) up to the 'knee' of the CR spectrum at 10{sup 15} eV, accelerating particles to relativistic energies in their blast waves by the process of diffusive shock acceleration (DSA). Since CR nuclei do not radiate efficiently, their presence must be inferred indirectly. Previous theoretical calculations and X-ray observations show that CR acceleration significantly modifies the structure of the SNR and greatly amplifies the interstellar magnetic field. We present new, deep X-ray observations of the remnant of Tycho's supernova (SN 1572, henceforth Tycho), which reveal a previously unknown, strikingly ordered pattern of non-thermal high-emissivity stripes in the projected interior of the remnant, with spacing that corresponds to the gyroradii of 10{sup 14}-10{sup 15} eV protons. Spectroscopy of the stripes shows the plasma to be highly turbulent on the (smaller) scale of the Larmor radii of TeV energy electrons. Models of the shock amplification of magnetic fields produce structure on the scale of the gyroradius of the highest energy CRs present, but they do not predict the highly ordered pattern we observe. We interpret the stripes as evidence for acceleration of particles to near the knee of the CR spectrum in regions of enhanced magnetic turbulence, while the observed highly ordered pattern of these features provides a new challenge to models of DSA.

Eriksen, Kristoffer A.; Hughes, John P. [Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854 (United States); Badenes, Carles [School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Fesen, Robert [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Ghavamian, Parviz [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Moffett, David [Department of Physics, Furman University, Greenville, SC 29613 (United States); Plucinksy, Paul P.; Slane, Patrick [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Rakowski, Cara E. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Reynoso, Estela M. [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina)

2011-02-20

356

Fermi-Lat and WMAP Observations of the Puppis a Supernova Remnant  

NASA Technical Reports Server (NTRS)

We report the detection of GeV gamma-ray emission from the supernova remnant Puppis A with the Fermi Gamma-Ray Space Telescope. Puppis A is among the faintest supernova remnants yet detected at GeV energies, with a luminosity of only 2.710(exp 34) (D/2.2 kpc)(exp 2) erg s(exp -1) between 1 and 100 GeV. The gamma-ray emission from the remnant is spatially extended, with a morphology matching that of the radio and X-ray emission, and is well described by a simple power law with an index of 2.1. We attempt to model the broadband spectral energy distribution, from radio to gamma-rays, using standard nonthermal emission mechanisms. To constrain the relativistic electron population we use 7 years of WMAP data to extend the radio spectrum up to 93 GHz. Both leptonic and hadronic dominated models can reproduce the nonthermal spectral energy distribution, requiring a total content of cosmic ray (CR) electrons and protons accelerated in Puppis A of at least WCR is approx. (1 - 5)10 (exp 49) erg.

Hewitt, John William; Grondin, M. H.; Lemoine-Goumard, M.; Reposeur, T.; Ballet, J.; Tanaka, T.

2012-01-01

357

The Chandra ACIS Survey of M33: X-ray, Optical, and Radio Properties of the Supernova Remnants  

NASA Astrophysics Data System (ADS)

M33 contains a large number of emission nebulae identified as supernova remnants (SNRs) based on the high [S II]:H? ratios characteristic of shocked gas. Using Chandra data from the ChASeM33 survey with a 0.35-2 keV sensitivity of ~2 1034 erg s-1, we have detected 82 of 137 SNR candidates, yielding confirmation of (or at least strongly support for) their SNR identifications. This provides the largest sample of remnants detected at optical and X-ray wavelengths in any galaxy, including the Milky Way. A spectral analysis of the seven X-ray brightest SNRs reveals that two, G98-31 and G98-35, have spectra that appear to indicate enrichment by ejecta from core-collapse supernova explosions. In general, the X-ray-detected SNRs have soft X-ray spectra compared to the vast majority of sources detected along the line of sight to M33. It is unlikely that there are any other undiscovered thermally dominated X-ray SNRs with luminosities in excess of ~4 1035 erg s-1 in the portions of M33 covered by the ChASeM33 survey. We have used a combination of new and archival optical and radio observations to attempt to better understand why some objects are detected as X-ray sources and others are not. We have also developed a morphological classification scheme for the optically identified SNRs and discussed the efficacy of this scheme as a predictor of X-ray detectability. Finally, we have compared the SNRs found in M33 to those that have been observed in the Galaxy and the Magellanic Clouds. There are no close analogs of Cas A, Kepler's SNR, Tycho's SNR, or the Crab Nebula in the regions of M33 surveyed, but we have found an X-ray source with a power-law spectrum coincident with a small-diameter radio source that may be the first pulsar-wind nebula recognized in M33.

Long, Knox S.; Blair, William P.; Winkler, P. Frank; Becker, Robert H.; Gaetz, Terrance J.; Ghavamian, Parviz; Helfand, David J.; Hughes, John P.; Kirshner, Robert P.; Kuntz, Kip D.; McNeil, Emily K.; Pannuti, Thomas G.; Plucinsky, Paul P.; Saul, Destry; Tllmann, Ralph; Williams, Benjamin

2010-04-01

358

Infrared and X-Ray Spectroscopy of the KES 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties  

NASA Technical Reports Server (NTRS)

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and ill emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Temim, Tea; Dwek, Eli; Slane, Patrick; Arendt, Richard G.

2009-01-01

359

Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties  

NASA Technical Reports Server (NTRS)

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of approximately 1.5 keY, or with two thermal components with temperatures of 1.5 and 0.2 keY. Previous studies suggest that the hot component may originate from reverse-shocked supernova (SN) ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from SN ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of approximately 140 K by a relatively dense, hot plasma that also gives rise to the hot X-my emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-my emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) x solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Temim, Tea; Slane, Patrick; Arendt, Richard G.; Dwek, Eli

2011-01-01

360

COSMIC-RAY ELECTRON EVOLUTION IN THE SUPERNOVA REMNANT RX J1713.7-3946  

SciTech Connect

A simple formalism to describe nonthermal electron acceleration, evolution, and radiation in supernova remnants (SNRs) is presented. The electron continuity equation is analytically solved assuming that the nonthermal electron injection power is proportional to the rate at which the kinetic energy of matter is swept up in an adiabatically expanding SNR shell. We apply this model to Fermi and HESS data from the SNR RX J1713.7-3946 and find that a one-zone leptonic model with Compton-scattered cosmic microwave background and interstellar infrared photons has difficulty providing a good fit to its spectral energy distribution, provided the source is at a distance {approx}1 kpc from the Earth. However, the inclusion of multiple zones, as hinted at by recent Chandra observations, does provide a good fit, but requires a second zone of compact knots with magnetic fields B {approx} 16 {mu}G, comparable to shock-compressed fields found in the bulk of the remnant.

Finke, Justin D.; Dermer, Charles D., E-mail: justin.finke@nrl.navy.mil [U.S. Naval Research Laboratory, Code 7653, 4555 Overlook Ave. SW, Washington, DC 20375-5352 (United States)

2012-05-20

361

Probing the Reverse Shock in an Oxygen-Rich Supernova Remnant  

NASA Astrophysics Data System (ADS)

We will use FUSE to examine locations around the X-ray bright ring seen in the high resolution Chandra X-ray observations of the oxygen-rich supernova remnant 1E0102.2-7219. Our three FUSE MDRS pointings will sample regions with differing distributions of OIIIf emission and X-ray emission (largely OVII and OVIII). An additional off-target pointing will assess the continuum scattered from stars in the nearby HII region, allowing for a more reliable background subtraction. The resulting detailed information about the distribution and kinematics of OVI relative to the other components will show whether the OVI contribution is associated more with the X-ray ring (an ionizing reverse shock) or with the OIIIf filamentation radiative shocks driven into denser ejecta). Lastly, an enumeration of the mass contributions from the various ionization stages will allow a more reliable determination of the mass of oxygen in the remnant.

Gaetz, Terrancej.

362

ANALYTICAL AND MONTE CARLO RESULTS FOR THE SURFACE-BRIGHTNESS-DIAMETER RELATIONSHIP IN SUPERNOVA REMNANTS  

SciTech Connect

The surface-brightness-diameter relationship for supernova remnants is explained by adopting a model of direct conversion of the flux of kinetic energy into synchrotron luminosity. Two laws of motion are adopted: a power-law model for the radius-time relationship and a model that uses the thin layer approximation. The fluctuations in the log-log surface diameter relationship are modeled by a Monte Carlo simulation. In this model, a new probability density function for the density as a function of the galactic height is introduced.

Zaninetti, Lorenzo, E-mail: zaninetti@ph.unito.it [Dipartimento di Fisica Generale, Via Pietro Giuria 1, 10125 Torino (Italy)

2012-02-10

363

Rayleigh-Taylor Instabilities in Young Supernova Remnants Undergoing Efficient Particle Acceleration  

E-print Network

We employ hydrodynamic simulations to study the effects of high shock compression ratios, as expected for fast shocks with efficient particle acceleration, on the convective instability of driven waves in supernova remnants. We find that the instability itself does not depend significantly on the compression ratio, but because the width of the interaction region between the forward and reverse shocks can shrink significantly with increasing shock compression, we find that convective instabilities can reach all the way to the forward shock front if compression ratios are high enough.

John M. Blondin; Donald C. Ellison

2001-06-14

364

Analysis of LAC Observations of Clusters of Galaxies and Supernova Remnants  

NASA Technical Reports Server (NTRS)

The following publications are included and serve as the final report: The X-ray Spectrum of Abell 665; Clusters of Galaxies; Ginga Observation of an Oxygen-rich Supernova Remnant; Ginga Observations of the Coma Cluster and Studies of the Spatial Distribution of Iron; A Measurement of the Hubble Constant from the X-ray Properties and the Sunyaev-Zel'dovich Effect of Abell 2218; Non-polytropic Model for the Coma Cluster; and Abundance Gradients in Cooling Flow Clusters: Ginga LAC (Large Area Counter) and Einstein SSS (Solid State Spectrometer) Spectra of A496, A1795, A2142, and A2199.

Hughes, J.

1996-01-01

365

The Velocity Structure of HI Emission Toward Supernova Remnant HB9  

NASA Astrophysics Data System (ADS)

Using Pisgah Astronomical Research Institute's (PARI) 26 meter West Radio Telescope, I investigated the velocity structure and overall presence of hydrogen in a region of the supernova remnant HB9 (Green, 2009). This was done by taking spectral data over a 142.5 by 127.5 arc minute grid surrounding the most intense region of hydrogen emission. The spectra were summed under the hydrogen peak to create an overall hydrogen map of the region. Spectra were also divided amongst different frequency channels to model the velocity structure of the hydrogen present in the region. My findings are compared with additional velocity and hydrogen composition maps (Leahy & Roger, 1991).

Griffeth, Alice; Castelaz, M.; Moffett, D.

2011-01-01

366

An Investigation into PAH Destruction in Nearby Supernova Remnants, North Polar Spur and Cygnus Loop  

NASA Astrophysics Data System (ADS)

Our goal in conducting this research was to look at the polycyclic aromatic hydrocarbon (PAH)/large dust grain emission intensity ratio in nearby supernova remnants to find evidence for selective PAH destruction by hot gas and high velocity shock waves within these regions, as predicted by the models of Arendt et al. (2010) and Micelotta et al. (2010a,b). Two supernova remnants were studied- the North Polar Spur (NPS) and the Cygnus Loop. The data for PAHs were obtained from the WISE W3 12 micron all-sky map processed by Meisner & Finkbeiner (2014), and the data for the larger grains come from the IRAS 100 micron all-sky map processed by Schlegel, Finkbeiner & Davis (1998). After obtaining a control PAH/large grain intensity ratio of ~2.8 (DN/px)/(MJy/sr) from two high latitude clouds, MBM 30 and MBM 32, we found that the intensity ratios across the NPS and Cygnus Loop were not far off- ~2.7 (DN/px)/(MJy/sr) and ~3.1 (DN/px)/(MJy/sr), respectively- showing no evidence of selective large-scale PAH destruction in supernova remnants. The individual intensities for both PAHs and large grains do decrease inside the Cygnus Loop, however, suggesting a decrease in abundances of both grain types, which could mean total dust grain destruction with the normal ratios coming from foreground and background dust located in the line of sight of the remnant. In addition, temperature and E(B-V) measurements taken from calibrated IRAS images show that while the dust column density increases in the Eastern Veil of the Cygnus Loop, the dust temperature reaches a local maximum, indicating the heating of large grains by interaction with the hot gas in the remnant. The PAH/large grain ratio in the Eastern Veil does decrease and could be indicative of currently ongoing active grain destruction there, with the PAHs being destroyed on a more rapid timescale than the large grains.We are grateful for financial support from the NSF REU Program grant to the Department of Physics & Astronomy at the University of Toledo.

Burkhart, Sarah M.; Witt, Adolf N.

2015-01-01

367

Induced Rotation in Three-dimensional Simulations of Core-collapse Supernovae: Implications for Pulsar Spins  

Microsoft Academic Search

It has been suggested that the observed rotation periods of radio pulsars might be induced by a non-axisymmetric spiral-mode instability in the turbulent region behind the stalled supernova bounce shock, even if the progenitor core was not initially rotating. In this paper, using the three-dimensional Adaptive Mesh Refinement code CASTRO with a realistic progenitor and equation of state and a

Emmanouela Rantsiou; Adam Burrows; Jason Nordhaus; Ann Almgren

2011-01-01

368

Induced Rotation in 3D Simulations of Core Collapse Supernovae: Implications for Pulsar Spins  

Microsoft Academic Search

It has been suggested that the observed rotation periods of radio pulsars\\u000amight be induced by a non-axisymmetric spiral-mode instability in the turbulent\\u000aregion behind the stalled supernova bounce shock, even if the progenitor core\\u000awas not initially rotating. In this paper, using the three-dimensional AMR code\\u000aCASTRO with a realistic progenitor and equation of state and a simple neutrino

E. Rantsiou; A. Burrows; J. Nordhaus; A. Almgren

2010-01-01

369

An X-ray study of five supernova remnants in the Carina spiral arm  

NASA Technical Reports Server (NTRS)

The ROSAT Position Sensitive Proportional Counter (PSPC) is used to perform an exploratory study of four fields in the Carina spiral arm containing five radio supernova remnants, only one of which has previously been studied in X-rays. We present upper limits for the detection in X-rays of G298.5 - 0.3, G298.6 - 0.0, and G299.0+0.2, and report a 4 sigma detection of G296.8-0.3. In addition, we present detailed spatial and spectral analysis of the bright X-ray remnant G296.1-0.7, which has previously been studied by both the Einstein IPC and EXOSAT LE/CMA. We detect relatively slight, but statistically significant, variations in the spectrum across the remnant via spatially resolved spectral fits and a study of the spatial variation of hardness ratios. In general, the spectrum is characteristic of a thermal plasma with kT about 0.2 keV and N(sub H) about 1.5 x 10(exp 21/sq. cm). The total X-ray emitting mass is estimated to be about 250 solar mass for an optically estimated distance of 4 kpc to the remnant. At this distance, the linear dimensions of the remnant are roughly 35 - 50 pc, implying an age on the order of 20,000 yr. Assuming that X-ray and radio brightnesses are related by SIGMA(sub R) proportional to SIGMA(exp 0.69)(sub X) and that the four radio remnants have X-ray spectral characteristics similar to G296.1-0.7, we find that the column densities to these sources must be several times 10(exp 22)/sq cm in order to explain their low X-ray count rates. This column density is considerably in excess of the X-ray fitted column density to G296.1-0.7, but is comparable to the total column densities in H I measured via the 21 cm line in the directions to all five remnants. This implies that G296.1 - 0.7 is at a significantly smaller distance than the other remnants.

Hwang, Una; Markert, Thomas H.

1994-01-01

370

Measurements of Amplified Magnetic Field and Cosmic-Ray Content in Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernova explosions drive collisionless shocks in the interstellar (or circumstellar) medium. Such shocks are mediated by plasma waves, resulting in the shock transition on a scale much smaller than the collisional mean free path. Galactic cosmic rays are widely considered to be accelerated at collisionless shocks in supernova remnants via diffusive shock acceleration. New high-energy data coming from the X-ray and gamma-ray satellites and from imaging air Cerenkov telescopes are making possible to study physics of particle acceleration at supernova shocks, such as magnetic field amplification which is considered to be realized as part of shock acceleration process and the energy content of cosmic-ray particles in the supernova shell. In particular, GeV observations with the Fermi Gamma-ray Space Telescope offer the prime means to establish the origin of the gamma-rays, and to measure the cosmic-ray content. Moreover they provide a new opportunity to learn about how particle acceleration responds to environ-mental effects. I will present recent observational results from the Chandra and Suzaku X-ray satellites and new results from the LAT onboard Fermi, and discuss their implications to the origin of galactic cosmic rays.

Uchiyama, Yasunobu

371

LIMITS ON THE NUMBER OF GALACTIC YOUNG SUPERNOVA REMNANTS EMITTING IN THE DECAY LINES OF {sup 44}Ti  

SciTech Connect

We revise the assumptions of the parameters involved in predicting the number of supernova remnants detectable in the nuclear lines of the decay chain of {sup 44}Ti. Specifically, we consider the distribution of the supernova progenitors, the supernova rate in the Galaxy, the ratios of supernova types, the Galactic production of {sup 44}Ti, and the {sup 44}Ti yield from supernovae of different types to derive credible bounds on the expected number of detectable remnants. We find that, within 1? uncertainty, the Galaxy should contain an average of 5.1{sup +2.4}{sub -2.0} remnants detectable to a survey with a {sup 44}Ti decay line flux limit of 10{sup 5} photons cm{sup 2} s{sup 1}, with a probability of detecting a single remnant of 2.7{sup +10.0}{sub -2.4}%, and an expected number of detections between two and nine remnants, making the single detection of Cas A unlikely but consistent with our models. Our results show that the probability of detecting the brightest {sup 44}Ti flux source at the high absolute Galactic longitude of Cas A or above is ?10%. Using the detected flux of Cas A, we attempt to constrain the Galactic supernova rate and Galactic production of {sup 44}Ti, but find the detection to be only weakly informative. We conclude that even future surveys having 200 times more sensitivity than state-of-the-art surveys can be guaranteed to detect only a few new remnants, with an expected number of detections between 8 and 21 at a limiting {sup 44}Ti decay flux of 10{sup 7} photons cm{sup 2} s{sup 1}.

Dufour, Franois; Kaspi, Victoria M., E-mail: dufourf@physics.mcgill.ca [Department of Physics, McGill University, 3600 rue University, Montral, QC H3A 2T8 (Canada)

2013-09-20

372

The acceleration of cosmic-ray protons in the supernova remnant RX J1713.7-3946  

Microsoft Academic Search

Protons with energies up to ~1015eV are the main component of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking. Electrons are known to be accelerated to cosmic-ray energies in supernova remnants, and the shock waves associated with such remnants, when they hit the surrounding interstellar medium, could also

R. Enomoto; T. Tanimori; T. Naito; T. Yoshida; S. Yanagita; M. Mori; P. G. Edwards; A. Asahara; G. V. Bicknell; S. Gunji; S. Hara; T. Hara; S. Hayashi; C. Itoh; S. Kabuki; F. Kajino; H. Katagiri; J. Kataoka; A. Kawachi; T. Kifune; H. Kubo; J. Kushida; S. Maeda; A. Maeshiro; Y. Matsubara; Y. Mizumoto; M. Moriya; H. Muraishi; Y. Muraki; T. Nakase; K. Nishijima; M. Ohishi; K. Okumura; J. R. Patterson; K. Sakurazawa; R. Suzuki; D. L. Swaby; K. Takano; T. Takano; F. Tokanai; K. Tsuchiya; H. Tsunoo; K. Uruma; A. Watanabe; T. Yoshikoshi

2002-01-01

373

IRAS 15099-5856: REMARKABLE MID-INFRARED SOURCE WITH PROMINENT CRYSTALLINE SILICATE EMISSION EMBEDDED IN THE SUPERNOVA REMNANT MSH15-52  

SciTech Connect

We report new mid-infrared (MIR) observations of the remarkable object IRAS 15099-5856 using the space telescopes AKARI and Spitzer, which demonstrate the presence of prominent crystalline silicate emission in this bright source. IRAS 15099-5856 has a complex morphology with a bright central compact source (IRS1) surrounded by knots, spurs, and several extended ({approx}4') arc-like filaments. The source is seen only at {>=}10 {mu}m. The Spitzer mid-infrared spectrum of IRS1 shows prominent emission features from Mg-rich crystalline silicates, strong [Ne II] 12.81 {mu}m, and several other faint ionic lines. We model the MIR spectrum as thermal emission from dust and compare with the Herbig Be star HD 100546 and the luminous blue variable R71, which show very similar MIR spectra. Molecular line observations reveal two molecular clouds around the source, but no associated dense molecular cores. We suggest that IRS1 is heated by UV radiation from the adjacent O star Muzzio 10 and that its crystalline silicates most likely originated in a mass outflow from the progenitor of the supernova remnant (SNR) MSH 15-52. IRS1, which is embedded in the SNR, could have been shielded from the SN blast wave if the progenitor was in a close binary system with Muzzio 10. If MSH 15-52 is a remnant of Type Ib/c supernova (SN Ib/c), as has been previously proposed, this would confirm the binary model for SN Ib/c. IRS1 and the associated structures may be the relics of massive star death, as shaped by the supernova explosion, the pulsar wind, and the intense ionizing radiation of the embedded O star.

Koo, Bon-Chul; Kim, Hyun-Jeong; Im, Myungshin [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); McKee, Christopher F. [Department of Physics and Astronomy, University of California, Berkeley, CA 94720 (United States); Suh, Kyung-Won [Department of Astronomy and Space Science, Chungbuk National University, Cheingju-City 361-763 (Korea, Republic of); Moon, Dae-Sik; Lee, Ho-Gyu [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Onaka, Takashi [Department of Astronomy, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Burton, Michael G. [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Hiramatsu, Masaaki [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Bessell, Michael S. [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory (Australia); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006 (Australia); Lee, Jae-Joon [Astronomy and Astrophysics Department, Pennsylvania State University, University Park, PA 16802 (United States); Jeong, Woong-Seob [Korea Astronomy and Space Science Institute, 61-1, Whaam-dong, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Tatematsu, Ken'ichi; Kawabe, Ryohei; Ezawa, Hajime [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588 (Japan); Kohno, Kotaro [Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Wilson, Grant; Yun, Min S., E-mail: koo@astrohi.snu.ac.kr [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

2011-05-01

374

Supernova basics Supernova types  

E-print Network

1 Supernovae · Supernova basics · Supernova types · Light Curves · SN Spectra ­ after explosion · Supernova Remnants (SNRs) · Collisional Ionization #12;2 Supernova Basics · Supernova (SN) explosions in our) · Typical SN rates ~ 1/Galaxy/century · Recent local supernovae: 1006 AD, 1054 AD (produced Crab nebula

Crenshaw, Michael

375

New X-ray lights on the supernova remnant population of the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) mark the end point of stellar evolution. They return nucleosynthesis products to the interstellar medium (ISM), enriching and mixing it with freshly-produced heavy elements. Studying SNRs in general, and their X-ray emission in particular, is crucial to advance our understanding of many important astrophysical processes. With an XMM-Newton Very Large Programme (PI: F. Haberl), we conducted an X-ray survey of the Large Magellanic Cloud (LMC). As opposed to the Milky Way, the LMC offers an ideal target, at a well-constrained distance with small absorption column densities. Thus, X-ray properties of the evolved end of the SNR population of a galaxy can be studied. I will present the characteristics of the newly X-ray-discovered SNRs, with emphasis on the discovery of several iron-rich SNRs, which are the most evolved remnants of type Ia (i.e. thermonuclear) supernovae. I will take advantage of the high level of completeness of our sample of SNRs to i) present the X-ray luminosity function (XLF) of LMC SNRs, extended towards lower-luminosity objects, comparing it to the XLF of SNRs in other galaxies; and ii) compare the spatial distribution of SNRs and star formation histories in the LMC.

Maggi, P.; Haberl, F.; Sasaki, M.; Kavanagh, P.; Filipovi?, M.; Bozzetto, L.; Points, S.; Chu, Y.; Gruendl, R.; Dickel, J.

2014-07-01

376

On the Influence of Supernova Remnant Thermal Energy in Powering Galactic Winds  

E-print Network

The fundamental tenet of the classical supernovae-driven wind model of elliptical galaxies is that the residual thermal energy of all supernovae remnants (SNRs) provide sufficient energy to overcome the binding energy of the remaining interstellar gas, thereby driving a global galactic wind. We re-examine model predictions of this epoch of wind ejection t_GW, highlighting a heretofore underappreciated sensitivity to the adopted remnant thermal energy formalism, and illustrating cases in which previous work may have substantially overestimated t_GW. Arguments based upon chemical evolution alone, put forth to reject the hypothesis of dark matter distributions similar to the luminous component in spheroids, are shown to be tenuous. Finally, the predicted enrichment of intracluster gas during the wind phase of cluster ellipticals, and its relation to the selected SNR interior thermal energy evolutionary scheme, is addressed. Despite the success of previous wind models, our results still call into question the correctness of the simple analytical approach used thus far, and imply that a more appropriate technique should be adopted in the future.

Brad K. Gibson

1994-10-11

377

AKARI AND BLAST OBSERVATIONS OF THE CASSIOPEIA A SUPERNOVA REMNANT AND SURROUNDING INTERSTELLAR MEDIUM  

SciTech Connect

We use new large area far infrared maps ranging from 65 to 500 {mu}m obtained with the AKARI and the Balloon-borne Large Aperture Submillimeter Telescope missions to characterize the dust emission toward the Cassiopeia A supernova remnant (SNR). Using the AKARI high-resolution data we find a new 'tepid' dust grain population at a temperature of {approx}35 K and with an estimated mass of 0.06 M{sub sun}. This component is confined to the central area of the SNR and may represent newly formed dust in the unshocked supernova ejecta. While the mass of tepid dust that we measure is insufficient by itself to account for the dust observed at high redshift, it does constitute an additional dust population to contribute to those previously reported. We fit our maps at 65, 90, 140, 250, 350, and 500 {mu}m to obtain maps of the column density and temperature of 'cold' dust (near 16 K) distributed throughout the region. The large column density of cold dust associated with clouds seen in molecular emission extends continuously from the surrounding interstellar medium to project on the SNR, where the foreground component of the clouds is also detectable through optical, X-ray, and molecular extinction. At the resolution available here, there is no morphological signature to isolate any cold dust associated only with the SNR from this confusing interstellar emission. Our fit also recovers the previously detected 'hot' dust in the remnant, with characteristic temperature 100 K.

Sibthorpe, B. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom); Ade, P. A. R.; Griffin, M.; Hargrave, P. C.; Mauskopf, P. [Department of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, J. J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Chapin, E. L.; Halpern, M.; Marsden, G. [Department of Physics and Astronomy, 6224 Agricultural Road, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Devlin, M. J.; Dicker, S.; Klein, J. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Gundersen, J. O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Hughes, D. H. [Instituto Nacional de Astrofisica, Optica y Electronica, Luis Enrique Erro 1, Tonantzintla, Puebla 72840 (Mexico); Jeong, W.-S. [Korea Astronomy and Space Science Institute, 61-1, Hwaam-dong, Yuseong-gu, Daejeon 305-348 (Korea, Republic of); Kaneda, H. [Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Koo, B.-C.; Lee, H.-G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Martin, P. G. [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Moon, D.-S., E-mail: bruce.sibthorpe@stfc.ac.u [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

2010-08-20

378

Computer simulations of cosmic-ray diffusion near supernova remnant shock waves  

NASA Technical Reports Server (NTRS)

A plasma simulation model was used to study the resonant interactions between streaming cosmic-ray ions and a self-consistent spectrum of Alfven waves, such as might exist in the interstellar medium upstream of a supernova remnant shock wave. The computational model is a hybrid one, in which the background interstellar medium is an MHD fluid and the cosmic-rays are discrete kinetic particles. The particle sources for the electromagnetic fields are obtained by averaging over the fast cyclotron motions. When the perturbed magnetic field is larger than 10 percent of the background field, the macro- and microphysics are no longer correctly predicted by quasi-linear theory. The particles are trapped by the waves and show sharp jumps in their pitch-angles relative to the background magnetic field, and the effective ninety-degree scattering time for diffusion parallel to the background magnetic field is reduced to between 5 and 30 cyclotron periods. Simulation results suggest that Type 1 supernova remnants may be the principal sites of cosmic ray acceleration.

Max, C. E.; Zachary, A. L.; Arons, J.

1989-01-01

379

Time-Dependent Diffusive Shock Acceleration in Slow Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

Recent gamma ray observations show that middle aged supernova remnants interacting with molecular clouds can be sources of both GeV and TeV emission. Models involving re-acceleration of pre-existing cosmic rays in the ambient medium and direct interaction between supernova remnant and molecular clouds have been proposed to explain the observed gamma ray emission. For the re-acceleration process, standard DSA theory in the test particle limit produces a steady state particle spectrum that is too flat compared to observations, which suggests that the high energy part of the observed spectrum has not yet reached a steady state. We derive a time dependent DSA solution in the test particle limit for situations involving re-acceleration of pre-existing cosmic rays in the preshock medium. Simple estimates with our time dependent DSA solution plus a molecular cloud interaction model can reproduce the overall shape of the spectra of IC 443 and W44 from GeV to TeV energies through pure ?^0-decay emission.We allow for a power law momentum dependence of the diffusion coefficient, finding that a power law index of 0.5 is favored.

Xiaping, Tang; Chevalier, Roger

2015-01-01

380

Particle Acceleration, Magnetic Field Generation and Emission from Relativistic Jets and Supernova Remnants  

NASA Technical Reports Server (NTRS)

We performed numerical simulations of particle acceleration, magnetic field generation, and emission from shocks in order to understand the observed emission from relativistic jets and supernova remnants. The investigation involves the study of collisionless shocks, where the Weibel instability is responsible for particle acceleration as well as magnetic field generation. A 3-D relativistic particle-in-cell (RPIC) code has been used to investigate the shock processes in electron-positron plasmas. The evolution of theWeibe1 instability and its associated magnetic field generation and particle acceleration are studied with two different jet velocities (0 = 2,5 - slow, fast) corresponding to either outflows in supernova remnants or relativistic jets, such as those found in AGNs and microquasars. Slow jets have intrinsically different structures in both the generated magnetic fields and the accelerated particle spectrum. In particular, the jet head has a very weak magnetic field and the ambient electrons are strongly accelerated and dragged by the jet particles. The simulation results exhibit jitter radiation from inhomogeneous magnetic fields, generated by the Weibel instability, which has different spectral properties than standard synchrotron emission in a homogeneous magnetic field.

Nishikawa, K.-I.; Hartmann, D. H.; Hardee, P.; Hededal, C.; Mizunno, Y.; Fishman, G. J.

2006-01-01

381

A 0.5 Msec Glance at the Supernova Remnant G21.5-0.9 with the Chandra X-ray Observatory  

Microsoft Academic Search

G21.5-0.9 is one of approximately 15 currently known Galactic filledcentre supernova remnants (plerions), the most well-known being the Crab Nebula. These filled-centre remnants lack a supernova remnant shell and typically have a larger size in radio than in X-ray. Early Chandra observations of G21.5-0.9 showed that the 40. radius plerion surrounded a 2. compact centre, and revealed a faint 150.

Heather Matheson; Samar Safi-Harb

2005-01-01

382

A Chandra X-Ray Survey of Ejecta in the Cassiopeia A Supernova Remnant  

NASA Technical Reports Server (NTRS)

We present a survey of the X-ray emitting ejecta in the Cassiopeia A supernova remnant based on an extensive analysis of over 6000 spectral regions extracted on 2.5-10" angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray emitting ejecta as well as showing the distribution of the mass of various elements over the remnant. The total shocked Fe mass appears to be roughly 0.14 Solar Mass, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si-burning and that associated with alpha-rich freeze-out, with a mass ratio of approximately 2:1. Surprisingly, essentially all of this Fe (both components) is well outside the central regions of the SNR, presumably having been ejected by hydrodynamic instabilities during the explosion. We discuss this, and its implications for the neutron star kick.

Hwang, Una; Laming, J. Martin

2011-01-01

383

Kepler's Supernova Remnant: A View from Chandra X-Ray Observatory  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

[figure removed for brevity, see original site] Figure 1

Each top panel in the composite above shows the entire remnant. Each color in the composite represents a different region of the electromagnetic spectrum, from X-rays to infrared light. The X-ray and infrared data cannot be seen with the human eye. Astronomers have color-coded those data so they can be seen in these images.

The bottom panels are close-up views of the remnant. In the bottom, center image, Hubble sees fine details in the brightest, densest areas of gas. The region seen in these images is outlined in the top, center panel.

The images indicate that the bubble of gas that makes up the supernova remnant appears different in various types of light. Chandra reveals the hottest gas [colored blue and colored green], which radiates in X-rays. The blue color represents the higher-energy gas; the green, the lower-energy gas. Hubble shows the brightest, densest gas [colored yellow], which appears in visible light. Spitzer unveils heated dust [colored red], which radiates in infrared light.

2004-01-01

384

High Resolution X-Ray Spectroscopy and Imaging of Supernova Remnant N132D  

NASA Technical Reports Server (NTRS)

The observation of the supernova remnant N132D by the scientific instruments on board the XMM-Newton satellite is presented. The X-rays from N132D are dispersed into a detailed line-rich spectrum using the Reflection Grating Spectrometers. Spectral lines of C, N, O, Ne, Mg, Si, S, and Fe are identified. Images of the remnant, in narrow wavelength bands, produced by the European Photon Imaging Cameras reveal a complex spatial structure of the ionic distribution. While K - shell Fe seems to originate near the centre, all of the other ions are observed along the shell. An emission excess of O(6+) over O(7+) is detected on the northeastern edge of the remnant. This can be a sign of hot ionising conditions, or it can reflect a relatively cool region. Spectral fitting of the CCD spectrum suggests high temperatures in this region, but a detailed analysis of the atomic processes involved in producing the O(6+) spectral lines leads to the conclusion that the intensities of these lines alone cannot provide a conclusive distinction between the two scenarios.

Behar, Ehud; Rasmussen, Andrew; Griffiths, R. Gareth; Dennerl, Konrad; Audard, Marc; Aschenbach, Bernd

2000-01-01

385

High-resolution X-ray spectroscopy and imaging of supernova remnant N132D  

E-print Network

The observation of the supernova remnant N132D by the scientific instruments on board the XMM-Newton satellite is presented. The X-rays from N132D are dispersed into a detailed line-rich spectrum using the Reflection Grating Spectrometers. Spectral lines of C, N, O, Ne, Mg, Si, S, and Fe are identified. Images of the remnant, in narrow wavelength bands, produced by the European Photon Imaging Cameras reveal a complex spatial structure of the ionic distribution. While K-shell Fe emission seems to originate near the centre, all of the other ions are observed along the shell. A high O VII / O VIII emission ratio is detected on the northeastern edge of the remnant. This can be a sign of hot ionising conditions, or it can reflect relatively cool gas. Spectral fitting of the CCD spectrum suggests high temperatures in this region, but a detailed analysis of the atomic processes involved in producing the O VII spectral lines leads to the conclusion that the intensities of these lines alone cannot provide a conclusive distinction between the two scenarios.

Ehud Behar; Andrew P. Rasmussen; R. Gareth Griffiths; Konrad Dennerl; Marc Audard; Bernd Aschenbach; Albert C. Brinkman

2000-11-15

386

Hard X-Ray Emission and 44Ti Line Features of the Tycho Supernova Remnant  

NASA Astrophysics Data System (ADS)

A deep hard X-ray survey of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected for the first time non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3-100 keV spectrum is fitted with a thermal bremsstrahlung of kT ~ 0.81 0.45 keV plus a power-law model of ? ~ 3.01 0.16. Based on diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that the Tycho remnant may not accelerate protons up to >PeV but to hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral "knee." In addition, using INTEGRAL, we search for soft gamma-ray lines at 67.9 and 78.4 keV that come from the decay of radioactive 44Ti in the Tycho remnant. A bump feature in the 60-90 keV energy band, potentially associated with the 44Ti line emission, is found with a marginal significance level of ~2.6?. The corresponding 3? upper limit on the 44Ti line flux amounts to 1.5 10-5 photon cm-2 s-1. Implications on the progenitor of the Tycho SN, considered to be a Type Ia SN prototype, are discussed.

Wang, Wei; Li, Zhuo

2014-07-01

387

AN ATTEMPT AT A UNIFIED MODEL FOR THE GAMMA-RAY EMISSION OF SUPERNOVA REMNANTS  

SciTech Connect

Shocks of supernova remnants (SNRs) are important (and perhaps the dominant) agents for the production of the Galactic cosmic rays. Recent {gamma}-ray observations of several SNRs have made this case more compelling. However, these broadband high-energy measurements also reveal a variety of spectral shapes demanding more comprehensive modeling of emissions from SNRs. According to the locally observed fluxes of cosmic-ray protons and electrons, the electron-to-proton number ratio is known to be about 1%. Assuming such a ratio is universal for all SNRs and identical spectral shape for all kinds of accelerated particles, we propose a unified model that ascribes the distinct {gamma}-ray spectra of different SNRs to variations of the medium density and the spectral difference between cosmic-ray electrons and protons observed from Earth to transport effects. For low-density environments, the {gamma}-ray emission is inverse-Compton dominated. For high-density environments like systems of high-energy particles interacting with molecular clouds, the {gamma}-ray emission is {pi}{sup 0}-decay dominated. The model predicts a hadronic origin of {gamma}-ray emission from very old remnants interacting mostly with molecular clouds and a leptonic origin for intermediate-age remnants whose shocks propagate in a low-density environment created by their progenitors via, e.g., strong stellar winds. These results can be regarded as evidence in support of the SNR origin of Galactic cosmic rays.

Yuan Qiang; Bi Xiaojun [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Liu Siming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2012-12-20

388

Mechanism for spectral break in cosmic ray proton spectrum of supernova remnant W44.  

PubMed

Recent observations of supernova remnant W44 by the Fermi spacecraft observatory support the idea that the bulk of galactic cosmic rays is accelerated in such remnants by a Fermi mechanism, also known as diffusive shock acceleration. However, the W44 expands into weakly ionized dense gas, and so a significant revision of the mechanism is required. Here, we provide the necessary modifications and demonstrate that strong ion-neutral collisions in the remnant surrounding lead to the steepening of the energy spectrum of accelerated particles by exactly one power. The spectral break is caused by Alfven wave evanescence leading to the fractional particle losses. The gamma-ray spectrum generated in collisions of the accelerated protons with the ambient gas is calculated and successfully fitted to the Fermi Observatory data. The parent proton spectrum is best represented by a classical test particle power law ?E(-2), steepening to E(-3) at E(br)?7?GeV due to deteriorated particle confinement. PMID:21326226

Malkov, M A; Diamond, P H; Sagdeev, R Z

2011-01-01

389

Molecule and dust reprocessing by the reverse shock in the supernova remnant Cas A  

NASA Astrophysics Data System (ADS)

Dust and molecules are observed in various supernovae (SNe) and their remnants, but their formation and evolution in these hostile, shocked environments are still unclear. In some remnants, such as the 330 years-old SN remnant Cas A, the reverse shock (RS) is currently reprocessing the material formed after the SN explosion. Recently, transitions of warm CO have been detected with the Spitzer, AKARI and Herschel telescopes in Cas A ([9], [12]). In particular, CO lines were detected with Herschel in a small O-rich clump, and a high CO column density and temperature, compatible with shocked gas, were derived from line modelling ([12]). These observations thus show that a fair quantity of CO reforms after the passage of the RS. The Cas A remnant results from the explosion of a 19 M star as a Type IIb supernova ([6]), characterised by a lowdensity ejecta. We first model the SN ejecta chemistry to identify the molecules and dust clusters that form after the explosion and are reprocessed by the RS. We find that Cas A progenitor could have formed large quantities of molecules and dust only in a dense ejecta involving clumps. We then model the impact of the RS on an oxygen-rich ejecta clump, considering various RS speeds and investigating the post-shock chemistry. We consider the destruction of molecules and dust clusters by the shock and their reformation using a chemical kinetic model. The impact of UV photons coming from the hot post-shock region on the ionization fraction of the post-shock gas is included. We also model the sputtering (thermal and non-thermal) of the dust by the RS. We found that the reverse shock destroys the molecules and clusters present in the O-rich clump. CO reforms in the post shock gas with abundances that concur with the latest Herschel observations, confirming a post-shock origin for the submm CO lines. We then derive a dust size distribution for the ejecta of the Cas A progenitor, and investigate the effect of different RS velocities on this dust size distribution. Our results show that medium- and large-sized grains can survive the RS and that small dust clusters do not efficiently reform in the shocked gas. This result indicates that the dust formed in the SN ejecta and destroyed by the RS is unable to reform from the gas phase in the SN remnant.

Biscaro, C.; Cherchneff, I.

390

Dense Iron-predominant Ejecta and Core-collapse Supernova Explosion in the Young Supernova Remnant G11.2-0.3  

NASA Astrophysics Data System (ADS)

We present the results of near-infrared spectroscopic observations of dense ( 103 cm-3) iron ejecta in the young core-collapse supernova remnant G11.2-0.3. Five ejecta knots projected to be close to its center show a large dispersion in their Doppler shifts: two knots in the east are blueshifted by more than 1,000 km s-1, while three western knots have blueshifts of 20-60 km s-1. One ejecta filament in the northwestern boundary, on the other hand, is redshifted by ? 200 km s-1, while another filament in the southeastern boundary shows a negligible radial motion. Some of the knots and filaments have secondary velocity components, deviating from a simple velocity structure. The Doppler shifts of the ejecta knots are suggestive of a systematic velocity shift of -500 km s-1 among the central ejecta knots moving in the opposite directions between the east and west, which also provides a plausible explanation of the velocity structures of some of the ejecta knots and filaments if they have been excited by the reverse shocks of the supernova remnant. The ejecta appear to be Fe-predominant, devoid of other elements, which may attest to the ?-rich freezeout process in the explosive nucleosynthesis of the core-collapse supernova explosion close to the core. This is the first identification of such Fe-predominant dense ejecta in supernova remnants. The prominent bipolar distribution of the Fe ejecta in the northwestern and southeastern direction advocates that the supernova exploded primarily along this direction. The Fe ejecta knots scattered across the supernova remnant might have been seeded by a hot Ni bubble created after the supernova explosion.

Moon, Dae-Sik; Koo, B.; Lee, H.; Matthews, K.; Lee, J.; Pyo, T.; Seok, J.; Hayashi, M.

2009-05-01

391

Could a Nearby Supernova Explosion have Caused a Mass Extinction?  

Microsoft Academic Search

We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc

John Ellis; David N. Schramm

1995-01-01

392

Fermi Large Area Telescope observations of the supernova remnant HESS J1731-347  

NASA Astrophysics Data System (ADS)

Context. HESS J1731-347 has been identified as one of the few TeV-bright shell-type supernova remnants (SNRs). These remnants are dominated by nonthermal emission, and the nature of TeV emission has been continuously debated for nearly a decade. Aims: We carry out the detailed modeling of the radio to ?-ray spectrum of HESS J1731-347 to constrain the magnetic field and energetic particles sources, which we compare with those of the other TeV-bright shell-type SNRs explored before. Methods: Four years of data from Fermi Large Area Telescope (LAT) observations for regions around this remnant are analyzed, leading to no detection correlated with the source discovered in the TeV band. The Markov chain Monte Carlo method is used to constrain parameters of one-zone models for the overall emission spectrum. Results: Based on the 99.9% upper limits of fluxes in the GeV range, one-zone hadronic models with an energetic proton spectral slope greater than 1.8 can be ruled out, which favors a leptonic origin for the ?-ray emission, making this remnant a sibling of the brightest TeV SNR RX J1713.7-3946, the Vela Junior SNR RX J0852.0-4622, and RCW 86. The best-fit leptonic model has an electron spectral slope of 1.8 and a magnetic field of ~30 ?G, which is at least a factor of 2 higher than those of RX J1713.7-3946 and RX J0852.0-4622, posing a challenge to the distance estimate and/or the energy equipartition between energetic electrons and the magnetic field of this source. A measurement of the shock speed will address this challenge and has implications on the magnetic field evolution and electron acceleration driven by shocks of SNRs.

Yang, Rui-zhi; Zhang, Xiao; Yuan, Qiang; Liu, Siming

2014-07-01

393

EVOLUTION OF THE RADIO REMNANT OF SUPERNOVA 1987A: MORPHOLOGICAL CHANGES FROM DAY 7000  

SciTech Connect

We present radio imaging observations of supernova remnant 1987A at 9 GHz, taken with the Australia Telescope Compact Array over 21 years from 1992 to 2013. By employing a Fourier modeling technique to fit the visibility data, we show that the remnant structure has evolved significantly since day 7000 (mid-2006): the emission latitude has gradually decreased such that the overall geometry has become more similar to a ring structure. Around the same time, we find a decreasing trend in the east-west asymmetry of the surface emissivity. These results could reflect the increasing interaction of the forward shock with material around the circumstellar ring, and the relative weakening of the interaction with the lower-density material at higher latitudes. The morphological evolution caused an apparent break in the remnant expansion measured with a torus model, from a velocity of 4600{sup +150}{sub -}200 km s{sup 1} between day 4000 and 7000 to 2400{sup +100}{sub -200} km s{sup 1} after day 7000. However, we emphasize that there is no conclusive evidence for a physical slowing of the shock at any given latitude in the expanding remnant, and that a change of radio morphology alone appears to dominate the evolution. This is supported by our ring-only fits which show a constant expansion of 3890 50 km s{sup 1} without deceleration between days 4000 and 9000. We suggest that once the emission latitude no longer decreases, the expansion velocity obtained from the torus model should return to the same value as that measured with the ring model.

Ng, C.-Y. [Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong); Zanardo, G.; Potter, T. M.; Staveley-Smith, L. [International Centre for Radio Astronomy Research (ICRAR), The University of Western Australia, Crawley, WA 6009 (Australia); Gaensler, B. M. [Australian Research Council, Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia); Manchester, R. N.; Tzioumis, A. K., E-mail: ncy@bohr.physics.hku.hk [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Marsfield, NSW 1710 (Australia)

2013-11-10

394

Chandra X-Ray Observatory Arcsecond Imaging of the Young, Oxygen-rich Supernova Remnant 1E 0102.2-7219.  

PubMed

We present observations of the young, oxygen-rich supernova remnant 1E 0102.2-7219 taken by the Chandra X-Ray Observatory during its orbital activation and checkout phase. The boundary of the blast-wave shock is clearly seen for the first time, allowing the diameter of the remnant and the mean blast-wave velocity to be determined accurately. The prominent X-ray bright ring of material may be the result of the reverse shock encountering ejecta; the radial variation of O vii versus O viii emission indicates an ionizing shock propagating inward, possibly through a strong density gradient in the ejecta. We compare the X-ray emission with Australia Telescope Compact Array 6 cm radio observations (Amy & Ball) and with archival Hubble Space Telescope [O iii] observations. The ring of radio emission is predominantly inward of the outer blast wave, which is consistent with an interpretation of synchrotron radiation originating behind the blast wave but outward of the bright X-ray ring of emission. Many (but not all) of the prominent optical filaments are seen to correspond to X-ray bright regions. We obtain an upper limit of approximately 9x1033 ergs s-1 (3 sigma) on any potential pulsar X-ray emission from the central region. PMID:10790068

Gaetz; Butt; Edgar; Eriksen; Plucinsky; Schlegel; Smith

2000-05-01

395

An Expanded HST/WFC3 Survey of M83: Project Overview and Targeted Supernova Remnant Search  

E-print Network

We present an optical/NIR imaging survey of the face-on spiral galaxy M83, using data from the Hubble Space Telescope Wide Field Camera 3 (WFC3). Seven fields are used to cover a large fraction of the inner disk, with observations in nine broadband and narrowband filters. In conjunction with a deep Chandra survey and other new radio and optical ground-based work, these data enable a broad range of science projects to be pursued. We provide an overview of the WFC3 data and processing and then delve into one topic, the population of young supernova remnants. We used a search method targeted toward soft X-ray sources to identify 26 new supernova remnants. Many compact emission nebulae detected in [Fe II] 1.644 micron align with known remnants and this diagnostic has also been used to identify many new remnants, some of which are hard to find with optical images. We include 37 previously identified supernova remnants that the data reveal to be <0.5'' in angular size and thus are difficult to characterize from ...

Blair, William P; Dopita, Michael A; Ghavamian, Parviz; Hammer, Derek; Kuntz, K D; Long, Knox S; Soria, Roberto; Whitmore, Bradley C; Winkler, P Frank

2014-01-01

396

Nonthermal X-Ray Emission from the Shell-Type Supernova Remnant G347.3-0.5  

NASA Technical Reports Server (NTRS)

Recent Advanced Spacecraft for Cosmology Astrophysics (ASCA) observations of G347.3-0.5, a supernova remnant (SNR) discovered in the ROSAT All-Sky Survey, reveal nonthermal emission from a region along the northwestern shell. Here we report on new pointed ASCA observations of G347.3-0.5 that confirm this result for all the bright shell regions and also reveal similar emission, although with slightly different spectral properties, from the remainder of the SNR. Curiously, no thermal X-ray emission is detected anywhere in the remnant. We derive limits on the amount of thermal emitting material present in G347.3-0.5 and present new radio continuum, CO, and infrared results that indicate that the remnant is distant and of moderate age. We show that our observations are broadly consistent with a scenario that has most of the supernova remnant shock wave still within the stellar wind bubble of its progenitor star, while part of it appears to be interacting with denser material. A point source at the center of the remnant has spectral properties similar to those expected for a neutron star and may represent the compact relic of the supernova progenitor.

Slane, Patrick O.; Gaensler, Bryan M.; Dame, T. M.; Hughes, John P.; Plucinsky, Paul P.; Green, Anne

2002-01-01

397

Very high energy gamma-ray emission from Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

Supernova remnant (SNR) G120.1+1.4 (also known as Tycho's SNR) is the remnant of one of only five confirmed historical supernovae. As such, it has been well studied across the electromagnetic spectrum. This thesis describes the first statistically significant detection of very high energy (VHE) ( 100 GeV to 100 TeV) gamma rays from Tycho's SNR, reported in 2011 by the VERITAS collaboration. The analysis that led to that detection was performed by this author, and this dissertation will discuss the process in detail. Subsequently, a statistically significant detection in high energy (HE) ( 30 MeV to 100 GeV) gamma rays was reported by other authors using data from the Fermi Gamma-Ray Space Telescope. Comparison of models to the spectral energy distribution of the photon flux from this remnant in HE and VHE gamma rays favors a hadronic origin for the emission, particularly when combined with current X-ray data, although a leptonic origin cannot be ruled out at this time. This is significant because a confirmed hadronic origin for the gamma-ray emission would identify this SNR as a site of cosmic ray acceleration, providing observational evidence for the idea that SNRs are the source of the Galactic cosmic ray population. Chapter 1 of this dissertation will provide historical background on Tycho's SNR, along with a summary of modern observations of the remnant across the electromagnetic spectrum. Chapter 2 is a discussion of the role played by SNRs in the process of cosmic ray acceleration, including both theoretical underpinnings and observational evidence. Chapter 3 provides an overview of the field of VHE gamma-ray astronomy, with discussions of gamma-ray production mechanisms and gamma-ray source classes. Chapter 4 describes the instruments used to observe HE and VHE gamma rays. Chapter 5 is a discussion of general analysis methods and techniques for data from Imaging Atmospheric Cherenkov Telescopes (IACTs). Chapter 6 provides details about the specific analysis I completed on VERITAS data on Tycho's SNR. Lastly, Chapter 7 discusses the modeling and interpretation of the VHE Tycho detection in the context of current multiwavelength observational results.

Saxon, Dana Boltuch

398

The Thermal Composite Supernova Remnant Kes 27 as Viewed by CHANDRA: Shock Reflection from a Cavity Wall  

E-print Network

We present a spatially resolved spectroscopic study of the thermal composite supernova remnant Kes 27 with Chandra. The X-ray spectrum of Kes 27 is characterized by K lines from Mg, Si, S, Ar, and Ca. The X-ray emitting gas is found to be enriched in sulphur and calcium. The broadband and tri-color images show two incomplete shell-like features in the northeastern half and brightness fading with increasing radius in the southwest. There are over 30 unresolved sources within the remnant. None show characteristics typical of young neutron stars. The maximum diffuse X-ray intensity coincides with a radio bright region along the eastern border. In general, gas in the inner region is at higher temperature and emission is brighter than from the outer region. The gas in the remnant appears to approach ionization equilibrium. The overall morphology can be explained by the evolution of the remnant in an ambient medium with a density enhancement from west to east. We suggest that the remnant was born in a pre-existing cavity and that the inner bright emission is due to the reflection of the initial shock from the dense cavity wall. This scenario may provide a new candidate mechanism for the X-ray morphology of other thermal composite supernova remnants.

Yang Chen; Frederick D. Seward; Ming Sun; Jiang-tao Li

2008-02-13

399

Two populations of X-ray pulsars produced by two types of supernova.  

PubMed

Two types of supernova are thought to produce the overwhelming majority of neutron stars in the Universe. The first type, iron-core-collapse supernovae, occurs when a high-mass star develops a degenerate iron core that exceeds the Chandrasekhar limit. The second type, electron-capture supernovae, is associated with the collapse of a lower-mass oxygen-neon-magnesium core as it loses pressure support owing to the sudden capture of electrons by neon and/or magnesium nuclei. It has hitherto been impossible to identify the two distinct families of neutron stars produced in these formation channels. Here we report that a large, well-known class of neutron-star-hosting X-ray pulsars is actually composed of two distinct subpopulations with different characteristic spin periods, orbital periods and orbital eccentricities. This class, the Be/X-ray binaries, contains neutron stars that accrete material from a more massive companion star. The two subpopulations are most probably associated with the two distinct types of neutron-star-forming supernova, with electron-capture supernovae preferentially producing systems with short spin periods, short orbital periods and low eccentricities. Intriguingly, the split between the two subpopulations is clearest in the distribution of the logarithm of spin period, a result that had not been predicted and which still remains to be explained. PMID:22080948

Knigge, Christian; Coe, Malcolm J; Podsiadlowski, Philipp

2011-11-17

400

The End of Amnesia: A New Method for Measuring the Metallicity of Type Ia Supernova Progenitors Using Manganese Lines in Supernova Remnants  

E-print Network

We propose a new method to measure the metallicity of Type Ia supernova progenitors using Mn and Cr lines in the X-ray spectra of young supernova remnants. We show that the Mn to Cr mass ratio in Type Ia supernova ejecta is tightly correlated with the initial metallicity of the progenitor, as determined by the neutron excess of the white dwarf material before thermonuclear runaway. We use this correlation, together with the flux of the Cr and Mn Kalpha X-ray lines in the Tycho supernova remnant recently detected by Suzaku (Tamagawa et al. 2008) to derive a metallicity of log(Z) = -1.32 (+0.67,-0.33) for the progenitor of this supernova, which corresponds to log(Z/Zsun)= 0.60 (+0.31,-0.60) according to the latest determination of the solar metallicity by Asplund et al. (2005). The uncertainty in the measurement is large, but metallicities much smaller than the solar value can be confidently discarded. We discuss the implications of this result for future research on Type Ia supernova progenitors.

Carles Badenes; Eduardo Bravo; John P. Hughes

2008-05-21

401

Near-infrared [Fe II] emission from supernova remnants and the supernova rate of starburst galaxies  

E-print Network

In an effort to better calibrate the supernova rate of starburst galaxies as determined from near-IR [Fe II] features, we report on a [Fe II] 1.644 microns line-imaging survey of a sample of 42 optically-selected SNRs in M33. A wide range of [Fe II] luminosities are observed within our sample (from less than 6 to 695 L_sun). Our data suggest that the bright [Fe II] SNRs are entering the radiative phase and that the density of the local ISM largely controls the amount of [Fe II] emission. We derive the following relation between the [Fe II] 1.644 microns line luminosity of radiative SNRs and the electronic density of the postshock gas, n_e: L_[Fe II] (L_sun) ~ 1.1 n_e (cm^-3). We also find a correlation in our data between L_[Fe II] and the metallicity of the shock-heated gas, but the physical interpretation of this result remains inconclusive, as our data also show a correlation between the metallicity and n_e. The dramatically higher level of [Fe II] emission from SNRs in the central regions of starburst galaxies is most likely due to their dense environments, although metallicity effects might also be important. The typical [Fe II]-emitting lifetime of a SNR in the central regions of starburst galaxies is found to be of the order of 10^4 yr. On the basis of these results, we provide a new empirical relation allowing the determination of the current supernova rate of starburst galaxies from their integrated near-IR [Fe II] luminosity.

T. Morel; R. Doyon; N. St-Louis

2001-10-23

402

DISCOVERY OF THE SMALL-DIAMETER, YOUNG SUPERNOVA REMNANT G354.4+0.0  

SciTech Connect

We report the discovery of a shell-like structure G354.4+0.0 of size 1.'6 that shows the morphology of a shell supernova remnant (SNR). Part of the structure shows polarized emission in a NRAO VLA sky survey map. Based on 330 MHz and 1.4 GHz Giant Metrewave Radio Telescope observations and existing observations at higher frequencies, we conclude that the partial shell structure showing synchrotron emission is embedded in an extended H II region of size {approx}4'. The spectrum of the diffuse H II region turns over between 1.4 GHz and 330 MHz. The H I absorption spectrum shows this objected to be located more than 5 kpc from Sun. Based on its morphology, non-thermal polarized emission, and size, this object is one of the youngest SNRs discovered in the Galaxy with an estimated age of {approx}100-500 yr.

Roy, Subhashis [NCRA-TIFR, Pune 411007 (India); Pal, Sabyasachi, E-mail: roy@ncra.tifr.res.in, E-mail: sabya@csp.res.in [Indian Centre for Space Physics, Kolkata 700084 (India)

2013-09-10

403

Systematic X-ray Mapping of Metal-Rich Ejecta in Bright Supernova Remnants.  

NASA Astrophysics Data System (ADS)

We apply our adaptive mesh technique coupled with simple automated NEI spectral modelings for archival Chandra data of several bright supernova remnants (SNRs) DEML71, N132D, E0102-72.3, G292.0+1.8, G299.2-2.9, Kepler, and Tycho. Based on the chi-square distributions of these model fits, we identify regions in which metal elements are enhanced compared to the circumstellar/interstellar abundances, and thus map over-abundant ejecta regions throughout these SNRs. With these maps we also reveal spatial structures of the individual ejecta elements O, Ne, Mg, Si, and Fe. We find that this simple chi-square mapping is effective to study spatial distributions of ejecta elements without performing extensive spectral model fits for individual sub-regions in SNRs. These ejecta maps may also be useful to reveal global structures such as the contact discontinuity. We present our preliminary results demonstrating the utility of this method.

Schenck, Andrew; Park, Sangwook; Bhalerao, Jayant; Post, Seth; Alan, Neslihan; Abualfoul, Mujahed

2015-01-01

404

Detection of the characteristic pion-decay signature in supernova remnants.  

PubMed

Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs. PMID:23413352

Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Busetto, G; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chaves, R C G; Chekhtman, A; Cheung, C C; Chiang, J; Chiaro, G; Cillis, A N; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbel, S; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; do Couto e Silva, E; Drell, P S; Drlica-Wagner, A; Falletti, L; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Hewitt, J W; Hill, A B; Hughes, R E; Jackson, M S; Jogler, T; Jhannesson, G; Johnson, A S; Kamae, T; Kataoka, J; Katsuta, J; Kndlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Madejski, G M; Massaro, F; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mignani, R P; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Rain, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Romoli, C; Snchez-Conde, M; Schulz, A; Sgr, C; Simeon, P E; Siskind, E J; Smith, D A; Spandre, G; Spinelli, P; Stecker, F W; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Thorsett, S E; Tibaldo, L; Tibolla, O; Tinivella, M; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S; Wood, M; Yamazaki, R; Yang, Z; Zimmer, S

2013-02-15

405

Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant  

NASA Technical Reports Server (NTRS)

Imaging and spectral observations of the Puppis A supernova remnant (SNR) with the Spitzer Space Telescope confirm that its IR emission is dominated by the thermal continuum emission of swept-up interstellar dust which is collisionally heated by the X-ray emitting gas of the SNR. Line emission is too weak to affect the fluxes measured in broadband observations, and is poorly correlated with the IR or X-ray emission. Modeling of spectra from regions both in the SNR and in the associated ISM show that the ubiquitous polycyclic aromatic hydrocarbons (PAHs) of the ISM are destroyed within the SNR, along with nearly 25% of the mass of graphite and silicate dust grains.

Arendt, Richard G.; Dwek, Eli,; Blair, William P.; Ghavamian, Parviz; Long, Knox S.

2010-01-01

406

The Second Epoch Molonglo Galactic Plane Survey: Images and Candidate Supernova Remnants  

NASA Astrophysics Data System (ADS)

The second epoch Molonglo Galactic Plane Survey covers the area 245 ? l ? 365 and |b| ? 10 at a frequency of 843 MHz and an angular resolution of 45 arcsec 45 arcsec cosec(?). The sensitivity varies between 1-2 mJy beam- 1 depending on the presence of strong extended sources. This survey is currently the highest resolution and most sensitive large-scale continuum survey of the southern Galactic plane. In this paper, we present the images of the complete survey, including postage stamps of some new supernova remnant (SNR) candidates and a discussion of the highly structured features detected in the interstellar medium. The intersection of these two types of features is discussed in the context of the `missing' SNR population in the Galaxy.

Green, A. J.; Reeves, S. N.; Murphy, T.

2014-11-01

407

Soft X-Ray Spectroscopy of the Cygnus Loop Supernova Remnant  

NASA Astrophysics Data System (ADS)

We present the results of a suborbital rocket flight whose scientific target was the Cygnus Loop Supernova Remnant. The payload consists of wire grid collimators, off-plane grating arrays, and gaseous electron multiplier (GEM) detectors. The system is designed for spectral measurements in the 17-107 bandpass with a resolution up to ~60 (?/??). The Extended X-ray Off-plane Spectrometer (EXOS) was launched on a Terrier-Black Brant rocket on 2009 November 13 from White Sands Missile Range and obtained 340 s of useable scientific data. The X-ray emission is dominated by O VII and O VIII, including the He-like O VII triplet at ~22 . Another emission feature at ~45 is composed primarily of Si XI and Si XII. The best-fit model to this spectrum is an equilibrium plasma model at a temperature of log(T) = 6.4 (0.23 keV).

Oakley, Phil; McEntaffer, Randall; Cash, Webster

2013-03-01

408

Detection of Class I Methanol (CH3OH) Maser Candidates in Supernova Remnants  

E-print Network

We have used the Karl G. Jansky Very Large Array (VLA) to search for 36 GHz and 44 GHz methanol (CH3OH) lines in a sample of 21 Galactic supernova remnants (SNRs). Mainly the regions of the SNRs with 1720 MHz OH masers were observed. Despite the limited spatial extent covered in our search, methanol masers were detected in both G1.4-0.1 and W28. Additional masers were found in SgrAEast. More than 40 masers were found in G1.4-0.1 which we deduce are due to interactions between the SNR and at least two separate molecular clouds. The six masers in W28 are associated with the molecular cloud that is also associated with the OH maser excitation. We discuss the possibility that the methanol maser may be