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1

TeV measurements of young pulsars and supernova remnants  

Microsoft Academic Search

Observations have been made with the University of Durham Mark 6 telescope of a number of supernova remnants and young pulsars (Vela pulsar, PSR B1055-52, PSR J1105-6107, PSR J0537-6910 and PSR B0540-69). No VHE gamma ray emission, either steady or pulsed, has been detected from these objects.

Paula Chadwick; K. Lyons; T. J. L. McComb; K. J. Orford; M. G. G. O'Connell; J. L. Osborne; S. M. Rayner; S. E. Shaw; K. E. Turver

1999-01-01

2

Are Pulsar Velocities Correlated with Supernova Remnant Ejecta Asymmetries?  

NASA Astrophysics Data System (ADS)

Proper motion studies have demonstrated that pulsars move with velocities much greater than those of their massive progenitors. These velocities span a distribution, with a mean of 380 km/s, and some pulsars are observed to have speeds up to two thousand km/s. These high speeds may arise from "kicks" imparted by asymmetric supernova explosions. To explore this scenario, we investigate whether ejecta asymmetries in supernova remnants (SNRs) are correlated with the inferred velocities of their central pulsars/neutron stars. In particular, we measure the asymmetry of ten SNRs in archival X-ray images using a multipole expansion technique, and we compare the results to pulsar/neutron star velocities from the literature. We find evidence that the SNRs with the fastest moving pulsars have the most mirror asymmetric ejecta, suggesting that pulsar kicks are indeed the result of asymmetry in the explosion mechanism.

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

2012-05-01

3

Magnetic Fields in Supernova Remnants and Pulsar-Wind Nebulae  

NASA Astrophysics Data System (ADS)

We review the observations of supernova remnants (SNRs) and pulsar-wind nebulae (PWNe) that give information on the strength and orientation of magnetic fields. Radio polarimetry gives the degree of order of magnetic fields, and the orientation of the ordered component. Many young shell supernova remnants show evidence for synchrotron X-ray emission. The spatial analysis of this emission suggests that magnetic fields are amplified by one to two orders of magnitude in strong shocks. Detection of several remnants in TeV gamma rays implies a lower limit on the magnetic-field strength (or a measurement, if the emission process is inverse-Compton upscattering of cosmic microwave background photons). Upper limits to GeV emission similarly provide lower limits on magnetic-field strengths. In the historical shell remnants, lower limits on B range from 25 to 1000 ?G. Two remnants show variability of synchrotron X-ray emission with a timescale of years. If this timescale is the electron-acceleration or radiative loss timescale, magnetic fields of order 1 mG are also implied. In pulsar-wind nebulae, equipartition arguments and dynamical modeling can be used to infer magnetic-field strengths anywhere from 5 ?G to 1 mG. Polarized fractions are considerably higher than in SNRs, ranging to 50 or 60% in some cases; magnetic-field geometries often suggest a toroidal structure around the pulsar, but this is not universal. Viewing-angle effects undoubtedly play a role. MHD models of radio emission in shell SNRs show that different orientations of upstream magnetic field, and different assumptions about electron acceleration, predict different radio morphology. In the remnant of SN 1006, such comparisons imply a magnetic-field orientation connecting the bright limbs, with a substantial density gradient across the remnant.

Reynolds, Stephen P.; Gaensler, B. M.; Bocchino, Fabrizio

2012-05-01

4

Future GLAST Observations of Supernova Remnants And Pulsar Wind Nebulae  

SciTech Connect

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. The 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 previously rather poorly explored energy band. We will describe prospects for the investigation of these Galactic particle accelerators with GLAST.

Funk, S.; /KIPAC, Menlo Park

2007-09-26

5

Supernova remnants  

NASA Astrophysics Data System (ADS)

This text is aimed at presenting the basic ingredients necessary to understand shell-type supernova remnants, with particular emphasis on their X-ray emission. The other observational domains (radio and optical) are mentioned but not discussed in depth. I do not discuss at all the synchrotron nebulae, such as the Crab Nebula, which are also relics of a supernova explosion, but are driven by the remaining pulsar rather than the mechanical energy of the supernova. After a brief historical introduction, I describe the hydrodynamic concepts used for supernova remnants. Then I describe the Sedov model governing middle-aged supernova remnants, and the coronal conditions under which the X-ray emission is computed. Quantitative formulae are given for the Sedov model, allowing to relate X-ray observations to energy, ambient density and age. A chapter describes the initial (young) and final (old) stages of supernova remnants. Cosmic-ray acceleration at shocks is described, as well as its consequences on supernova remnants. The final chapter deals with statistical issues.

Ballet, J.

6

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

7

A search for VHE gamma rays from young pulsars and supernova remnants in the Southern Hemisphere  

Microsoft Academic Search

Observations have been made with the University of Durham Mark 6 telescope of a number of supernova remnants and young pulsars (PSR B1706-44, Vela pulsar, PSR B1055-52, PSR J1105-6107, PSR J0537-6910 and PSR B0540-69). Although steady emission has been seen from PSR B1706-44, no VHE gamma ray emission, either steady or pulsed, has been detected from the other objects. Implications

P. M. Chadwick; K. Lyons; T. J. L. McComb; K. J. Orford; J. L. Osborne; S. M. Rayner; S. E. Shaw; K. E. Turver

2000-01-01

8

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

2008-10-16

9

Multi-wavelength observations of pulsar wind nebulae and composite supernova remnants  

NASA Astrophysics Data System (ADS)

Multi-wavelength studies of pulsar wind nebulae (PWNe) and supernova remnants (SNRs) lead to a better understanding of their evolutionary development, the interaction of supernovae (SNe) and pulsar winds with their surroundings, and nucleosynthesis and production and processing of dust grains by SNe. PWNe and composite supernova remnants, in particular, are unique laboratories for the study of the energetic pulsar winds, particle injection processes, and the impact of PWNe on the evolving SNR. They provide information on SNR shock properties, densities and temperatures, and the chemical composition and the ionization state of the material ejected by SNe. SNRs also serve as laboratories for the study of dust production and processing in SNe. While X-ray observations yield important information about the SN progenitor, hot gas properties, SN explosion energy, and the surrounding interstellar medium (ISM), the IR can provide crucial information about the faint non-thermal emission, continuum emission from dust, and forbidden line emission from SN ejecta. Combining observations at a wide range of wavelengths provides a more complete picture of the SNR development and helps better constrain current models describing a SNR's evolution and its impact on the surrounding medium. This thesis focuses on a multi-wavelength study of PWNe in various stages of their evolution and investigates their interaction with the expanding SN ejecta and dust and the SNR reverse shock. The study of these interactions can provide important information on the SNR properties that may otherwise be unobservable. The work in this thesis has been carried out under the supervision of Patrick Slane at the Harvard-Smithsonian Center for Astrophysics, and Charles E. Woodward and Rebert D. Gehrz at the University of Minnesota. The first part of the thesis summarizes the evolution and observational properties of SNRs and PWNe, with a focus on the evolution of young PWNe that are sweeping up inner SN ejecta. Two cases studies of such systems are discussed; infrared observations of the Crab Nebula; and X-ray and IR observations of G54.1+0.3. The second part of the thesis concentrates on the late stages of PWN evolution in which the PWN interacts with the SNR reverse shock. The final case study describes the X-ray observations of G327.1-1.1, a composite SNR in a late stage of its evolution. The thesis concludes with a summary of the results and proposed future work.

Temim, Tea

10

NuSTAR Galactic Science: Targeted Observations Of Magnetars, Pulsars, Binaries, Supernova Remnants And More  

NASA Astrophysics Data System (ADS)

The Nuclear Spectroscopic Telescope Array (NuSTAR), scheduled for launch in February 2012, will enable sensitive studies of high-energy sources in the Milky Way Galaxy at an unprecedented depth in the 5-80 keV range. Here we describe the NuSTAR targeted Galactic science observing plan. In particular, we describe our plan and science motivations for NuSTAR observations of: magnetars, with monitoring and target-of-opportunity components, to study spectra and variability properties; rotation-powered pulsars and pulsar wind nebula, to study the energy spectra of both and the hard X-ray morphology of the latter; X-ray binaries including both high-and low-mass varieties for a variety of purposes; gamma-ray binaries to study orbital-phase-dependent spectral changes and do pulsation searches; multiple star-formation regions to study pre-main-sequence flares; the Galactic Center region to study Sag A*; and several young supernova remnants, for spatially resolved high-resolution spectroscopy.

Kaspi, Victoria M.; NuSTAR Team

2011-09-01

11

A high-energy catalogue of Galactic supernova remnants and pulsar wind nebulae  

NASA Astrophysics Data System (ADS)

Motivated by the wealth of past, existing, and upcoming X-ray and gamma-ray missions, we have developed the first public database of high-energy observations of all known Galactic Supernova Remnants (SNRs): http://www.physics.umanitoba.ca/snr/SNRcat The catalogue links to, and complements, other existing related catalogues, including Dave Green's radio SNRs catalogue. We here highlight the features of the high-energy catalogue, including allowing users to filter or sort data for various purposes. The catalogue is currently targeted to Galactic SNR observations with X-ray and gamma-ray missions, and is timely with the upcoming launch of X-ray missions (including Astro-H in 2014). We are currently developing the existing database to include an up-to-date Pulsar Wind Nebulae (PWNe)-dedicated webpage, with the goal to provide a global view of PWNe and their associated neutron stars/pulsars. This extensive database will be useful to both theorists to apply their models or design numerical simulations, and to observers to plan future observations or design new instruments. We welcome input and feedback from the SNR/PWN/neutron stars community.

Safi-Harb, Samar; Ferrand, Gilles; Matheson, Heather

2013-03-01

12

Supernova remnants  

NASA Astrophysics Data System (ADS)

The images of supernova remnants (SNRs) with unusual morphology are presented. Some of them are unique, e.g., the semicircular shell of CTB109 and a string of infrared knots around SS433. The others are rather representational, e.g., the morphology of center-brightened but without central compact point source and that of the double lobes and bipolar in radio and so on. A series of theoretical models for the unusual morphology of SNRs are suggested by us and are listed here. It can be seen from our models that the fundamental reasons of unusual morphology of SNRs are the diversification of the interstellar medium, circumstellar medium around their supernovae and the nature or activity of their progenitors. Besides, the great achievement of Chandra (the newest X-ray satellite launched by NASA) is introduced. The images of several famous SNRs obtained from Chandra are presented, and simple explanation of them is given.

Wang, Zhenru

2001-06-01

13

Supernovae and supernova remnants  

NASA Astrophysics Data System (ADS)

This paper reviews the abundance results obtained in recent years for supernovae (SNs) and supernova remnants (SNRs), with special attention given to remnants that originate from historical SNs or in which velocities in the filaments are large, implying an age of less than 2000 years. These include the Crab Nebula, Kepler, SN 1006, Cas A, and Puppis A objects, SNR in NGC 4449, oxygen-rich SNRs, and SNRs LMC N132D and SMC 0102-72.3. Evidence is presented indicating the possibility of elucidating in a direct observational way the SNRs whose progenitors that are similar to observed SNs in external galaxies.

Danziger, I. J.; Bouchet, P.

14

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

National Technical Information Service (NTIS)

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 82...

F. Camilo I. H. Stairs D. R. Lorimer D. C. Backer S. M. Ransom B. Klein R. Wielebinski M. Kramer M. A. McLaughlin Z. Arzoumanian

2002-01-01

15

Discovery of the Energetic Pulsar J1747-2809 in the Supernova Remnant G0.9+0.1  

NASA Astrophysics Data System (ADS)

The supernova remnant G0.9+0.1 has long been inferred to contain a central energetic pulsar. In observations with the NRAO Green Bank Telescope at 2 GHz, we have detected radio pulsations from PSR J1747-2809. The pulsar has a rotation period of 52 ms, and a spin-down luminosity of \\dot{E} = 4.310^{37} erg s-1, the second largest among known Galactic pulsars. With a dispersion measure of DM = 1133 pc cm-3, PSR J1747-2809 is distant, at ?13 kpc according to the NE2001 electron density model, although it could be located as close as the Galactic center. The pulse profile is greatly scatter-broadened at a frequency of 2 GHz, so that it is effectively undetectable at 1.4 GHz, and is very faint, with period-averaged flux density of 40 ?Jy at 2 GHz.

Camilo, F.; Ransom, S. M.; Gaensler, B. M.; Lorimer, D. R.

2009-07-01

16

Supernovae and pulsars  

NASA Astrophysics Data System (ADS)

The simultaneous history of supernovae, pulsars, and Adriaan Blaauw's astronomical career is presented, and an account is given of the progress made in the areas of progenitor identification and ejection mechanisms. Only nine of the more than 100 supernova (SN) remnants in the galaxy show radio or X-ray evidence for a pulsar (or other type of neutron star) near their centers. Greater understanding of the progenitors and causes of SN explosions has been achieved through: (1) detection of radio emission from an SN I, (2) the detection of Wolf-Rayet-like lines in an SN II before maximum light, and (3) models for envelope ejection in Type-II's in which late-time neutrino heating and oxygen burning in infalling layers contribute significantly.

Trimble, V.

17

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

NASA Astrophysics Data System (ADS)

The Fermi Large Area Telescope 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 ?-ray pulsar PSR J0007+7303 (P = 315.8 ms; dot{P} 3.6 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 (1.4 kpc), interstellar absorption (AV 1.6), and relatively high energy loss rate (dot{E} 4.5 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 images down to a limit of r' 27.6 (3?), the deepest ever obtained for this pulsar, while William Herschel Telescope images yield a limit of V 26.9. Our r'-band limit corresponds to an optical emission efficiency ? _opt equiv L_opt/dot{E} lesssim 9.4 10^{-8}. This limit is more constraining than those derived for other Vela-like pulsars, but is still above the measured optical efficiency of the Vela pulsar. We compared the optical upper limits with the extrapolation of the XMM-Newton X-ray spectrum and found that the optical emission is compatible with the extrapolation of the X-ray power-law component, at variance with what is observed, e.g. in the Vela pulsar.

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

2013-04-01

18

A THOROUGH INVESTIGATION OF THE DISTANCE TO THE SUPERNOVA REMNANT CTB109 AND ITS PULSAR AXP J2301+5852  

SciTech Connect

CTB109 is one of only three Galactic supernova remnants (SNRs) known to harbor an anomalous X-ray pulsar or magnetar. That makes this SNR an object of great importance and a prime target for high-energy astrophysics studies. Those studies rely heavily on the assumed distance to CTB109. There have been three major distance determinations over the last decade, all of which report completely different results. While chaotic distance determinations in the literature are not uncommon for SNRs as a class of object, the wild discrepancy in the distance to CTB109 makes it especially important to revisit and firmly resolve once and for all. In this Letter we bring to bear all available observational information and present a synthesis of evidence that consistently locates CTB109 within or close to the Perseus arm spiral shock, at a distance of 3.2 {+-} 0.2 kpc.

Kothes, R. [National Research Council Canada, Herzberg Institute of Astrophysics, Dominion Radio Astrophysical Observatory, P.O. Box 248, Penticton, British Columbia V2A 6J9 (Canada); Foster, T., E-mail: roland.kothes@nrc-cnrc.gc.ca, E-mail: fostert@brandonu.ca [Department of Physics and Astronomy, Brandon University, 270 18th Street, Brandon, MB R7A 6A9 (Canada)

2012-02-10

19

The Duck Redux: An Improved Proper-Motion Upper Limit for the Pulsar B1757-24 near the Supernova Remnant G5.4-1.2  

NASA Astrophysics Data System (ADS)

``The Duck'' is a complicated nonthermal radio system, consisting of the energetic radio pulsar B1757-24, its surrounding pulsar wind nebula G5.27-0.90, and the adjacent supernova remnant (SNR) G5.4-1.2. PSR B1757-24 was originally claimed to be a young (~15,000 yr) and extreme-velocity (>~1500 km s-1) pulsar, which had penetrated and emerged from the shell of the associated SNR G5.4-1.2 but recent upper limits on the pulsar's motion have raised serious difficulties with this interpretation. We here present 8.5 GHz interferometric observations of the nebula G5.27-0.90 over a 12 yr baseline, doubling the time span of previous measurements. These data correspondingly allow us to halve the previous upper limit on the nebula's westward motion to 14 mas yr-1 (5 ?), allowing a substantive reevaluation of this puzzling object. We rule out the possibility that the pulsar and SNR were formed from a common supernova explosion ~15,000 yr ago, as implied by the pulsar's characteristic age, but conclude that an old (>~70,000 yr) pulsar/SNR association, or a situation in which the pulsar and SNR are physically unrelated, are both still viable explanations.

Blazek, J. A.; Gaensler, B. M.; Chatterjee, S.; van der Swaluw, E.; Camilo, F.; Stappers, B. W.

2006-12-01

20

Absence of pulsar ghost remnants  

Microsoft Academic Search

Results are reported of a high-sensitivity, high-resolution search for extended nonthermal radio emission associated with old pulsars (ghost remnants). Regions around eight pulsars previously suggested as having associated extended emission were observed at 18 cm with the Very Large Array and mapped at resolutions of 1 and 10 arcsec. Although all the fields examined contained sources other than the pulsar,

N. L. Cohen; W. D. Cotton; B. J. Geldzahler; J. M. Marcaide

1983-01-01

21

A BeppoSAX observation of the X-ray pulsar 1E 2259+586 and the supernova remnant G109.1-1.0 (CTB 109)  

Microsoft Academic Search

The 7 s X-ray pulsar 1E2259+586 and the supernova remnant (SNR) G109.1-1.0\\u000a(CTB 109) were observed by BeppoSAX in 1996 November. The pulse period of\\u000a6.978914 +\\/- 0.000006 s implies that the source continues its near constant\\u000aspin-down trend. The 0.5-10 keV pulse shape is characterized by a double peaked\\u000aprofile, with the amplitude of the second peak ~50% of

A. N. Parmar; T. Oosterbroek; F. Favata; S. Pightling; M. J. Coe; S. Mereghetti; G. L. Israel

1997-01-01

22

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

23

Upper limits on radio emission from the young X-ray pulsars in the supernova remnants G11. 2-0. 3 and N157B  

NASA Astrophysics Data System (ADS)

Using the Parkes radio telescope, we have searched for pulsed radio emission from the recently discovered X-ray pulsars AX J1811.5-1926 and PSR J0537-6910 in the supernova remnants G11.2-0.3 and N157B, respectively. We detected no significant pulsed radio emission from these pulsars and have set an upper limit of 0.07 mJy on the 1374 MHz flux from AX J1811.5-1926 and upper limits of 0.18 mJy and 0.06 mJy for the flux from PSR J0537-6910 at 660 MHz and 1374 MHz, respectively. Assuming a power law radio spectral index of 2, these flux limits correspond to luminosity limits at 400 MHz of 20 mJy kpc^2 for AX J1811.5-1926 and 1100 mJy kpc^2 for PSR J0537-6910. Our luminosity limit for AX J1811.5-1926 is lower than the observed luminosities of other young radio pulsars. The upper limit on the luminosity for PSR J0537-6910 in N157B is not significantly constraining due to the large distance to the pulsar. We have also searched for giant radio pulses from both pulsars and have found no convincing candidates.

Crawford, F.; Kaspi, V. M.; Manchester, R. N.; Camilo, F.; Lyne, A. G.; D'Amico, N.

24

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

25

Chandra and XMM-Newton Studies of the Supernova Remnant G292.2-0.5 Associated with the Pulsar J1119-6127  

NASA Astrophysics Data System (ADS)

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+0.3 -0.2 keV in the western side of the remnant to 2.3+2.9 -0.5 keV in the east, a column density increasing from 1.0+0.1 -0.6 1022 cm-2 in the west to 1.8+0.2 -0.4 1022 cm-2 in the east, and a low ionization timescale ranging from (5.7+0.8 -0.7) 109 cm-3 s in the SNR interior to (3.6+0.7 -0.6) 1010 cm-3 s in the western sidesuggestive 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 ~30 M ? 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; Gonzalez, Marjorie E.

2012-08-01

26

The Honeycomb supernova remnant  

NASA Astrophysics Data System (ADS)

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 (Snu is proportional to nu-1.2), normally associated with young SNRs.

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

1995-04-01

27

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

28

The slow X-ray pulsar SXP 1062 and associated supernova remnant in the Wing of the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

SXP 1062 is an exceptional case of a young neutron star in a wind-fed high-mass X-ray binary associated with a supernova remnant. A unique combination of measured spin period, its derivative, luminosity and young age makes this source a key probe for the physics of accretion and neutron star evolution. Theoretical models proposed to explain the properties of SXP 1062 shall be tested with new data.

Oskinova, L. M.; Guerrero, M. A.; Hnault-Brunet, V.; Sun, W.; Chu, Y.-H.; Evans, C.; Gallagher, J. S.; Gruendl, R. A.; Reyes-Iturbide, J.

2013-03-01

29

DISCOVERY OF A HIGHLY ENERGETIC PULSAR ASSOCIATED WITH IGR J14003-6326 IN THE YOUNG UNCATALOGED GALACTIC SUPERNOVA REMNANT G310.6-1.6  

SciTech Connect

We report the discovery of 31.18 ms pulsations from the INTEGRAL source IGR J14003-6326 using the Rossi X-ray Timing Explorer (RXTE). This pulsar is most likely associated with the bright Chandra X-ray point source lying at the center of G310.6-1.6, a previously unrecognized Galactic composite supernova remnant (SNR) with a bright central non-thermal radio and X-ray nebula, taken to be the pulsar wind nebula (PWN). PSR J1400-6325 is amongst the most energetic rotation-powered pulsars in the Galaxy, with a spin-down luminosity of E-dot = 5.1x10{sup 37} erg s{sup -1}. In the rotating dipole model, the surface dipole magnetic field strength is B{sub s} = 1.1 x 10{sup 12} G and the characteristic age {tau}{sub c{identical_to}}P/2 P-dot = 12.7 kyr. The high spin-down power is consistent with the hard spectral indices of the pulsar and the nebula of 1.22 {+-} 0.15 and 1.83 {+-} 0.08, respectively, and a 2-10 keV flux ratio F {sub PWN}/F {sub PSR} {approx} 8. Follow-up Parkes observations resulted in the detection of radio emission at 10 and 20 cm from PSR J1400-6325 at a dispersion measure of {approx}560 cm{sup -3} pc, which implies a relatively large distance of 10 {+-} 3 kpc. However, the resulting location off the Galactic plane of {approx}280 pc would be much larger than the typical thickness of the molecular disk, and we argue that G310.6-1.6 lies at a distance of {approx}7 kpc. There is no gamma-ray counterpart to the nebula or pulsar in the Fermi data published so far. A multi-wavelength study of this new composite SNR, from radio to very high-energy gamma rays, suggests a young ({approx}<10{sup 3} yr) system formed by a sub-energetic ({approx}<10{sup 50} erg), low ejecta mass (M {sub ej} {approx} 3 M {sub sun}) supernova explosion that occurred in a low-density environment (n {sub 0{approx}} 0.01 cm{sup -3}).

Renaud, M.; Marandon, V.; Terrier, R.; Mattana, F.; Lebrun, F. [AstroParticule et Cosmologie (APC), CNRS-UMR 7164, Universite Paris 7 Denis Diderot, F-75205 Paris (France); Gotthelf, E. V. [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, New York, NY 10027 (United States); Rodriguez, J. [CEA Saclay, Laboratoire AIM, CNRS-UMR 7158, DSM/IRFU/Service d'Astrophysique, F-91191 Gif-sur-Yvette (France); Tomsick, J. A. [Space Sciences Laboratory, 7 Gauss Way, University of California, Berkeley, CA 94720-7450 (United States); Manchester, R. N., E-mail: mrenaud@lpta.in2p3.f [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping NSW 1710 (Australia)

2010-06-10

30

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

31

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

32

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

33

OH Masers and Supernova Remnants  

NASA Astrophysics Data System (ADS)

OH(1720 MHz) masers are created by the interaction of supernova remnants with molecular clouds. These masers are pumped by collisions in warm, shocked molecular gas with OH column densities in the range 1016-1017, cm-2. Excitation calculations suggest that inversion of the 6049 MHz OH line may occur at the higher column densities that have been inferred from main-line absorption studies of supernova remnants with the Green Bank Telescope. OH(6049 MHz) masers have therefore been proposed as a complementary indicator of remnant-cloud interaction. This motivated searches for 6049 MHz maser emission from supernova remnants using the Parkes 63 m and Effelsberg 100 m telescopes, and the Australia Telescope Compact Array. A total of forty-one remnants have been examined by one or more of these surveys, but without success. To check the accuracy of the OH column densities inferred from the single-dish observations we modelled OH absorption at 1667 MHz observed with the Very Large Array towards three supernova remnants, IC 443, W44 and 3C 391. The results are mixed - the OH column is revised upwards in IC443, downwards in 3C391, and is somewhat reduced in W44. We conclude that OH columns exceeding 1017 cm-2 are indeed present in some supernova remnants and so the lack of any detections is not explained by low OH column density. We discuss the possibility that non-local line overlap is responsible for suppressing the inversion of the 6049 MHz line.

Wardle, Mark; McDonnell, Korinne

2012-07-01

34

PSR J1016-5857: A YOUNG RADIO PULSAR WITH POSSIBLE SUPERNOVA REMNANT, XRAY, AND RAY ASSOCIATIONS  

Microsoft Academic Search

We report the discovery of a young and energetic pulsar in the Parkes multibeam survey of the Galactic plane. PSR J1016-5857 has a rotation period of 107 ms and period derivative of 8.0 10-14, implying a characteristic age of 21 kyr and spin-down luminosity of 2.6 1036 erg s-1. The pulsar is located just outside, and possibly interacting

F. CAMILO; J. F. BELL; R. N. MANCHESTER; A. G. LYNE; A. POSSENTI; M. KRAMER; V. M. KASPI; I. H. STAIRS; G. HOBBS; E. V. GOTTHELF; B. M. GAENSLER

35

Electron acceleration in young supernova remnants  

Microsoft Academic Search

There is evidence for production of relativistic electrons and amplification of magnetic fields in young supernova remnants. In a recent publication we have given a model for radio emission from SN 1993J [1]. In this paper we discuss theories of electron acceleration in supernova remnants such as SN 1993J. Similarities between particle acceleration processes in supernova remnants and radio galaxies

William K. Rose

2001-01-01

36

Antimatter Production in Supernova Remnants  

Microsoft Academic Search

We calculate the energy spectra of cosmic rays (CRs) and their secondaries produced in a supernova remnant (SNR) taking into account the time dependence of the SNR shock. We model the trajectories of charged particles as a random walk with a prescribed diffusion coefficient, accelerating the particles at each shock crossing. Secondary production by CRs colliding with gas is included

M. Kachelriess; S. Ostapchenko; R. Toms

2011-01-01

37

Neutrinos from Supernovas and Supernova Remnants  

SciTech Connect

Supernovae (SN) and supernova remnants (SNR) have key roles in galaxies, but their physical descriptions is still incomplete. Thus, it is of interest to study neutrino radiation to understand SN and SNR better. We will discuss: (1) The {approx}10 MeV thermal neutrinos that arise from core collapse SN, that were observed for SN1987A, and can be seen with several existing or planned experiments. (2) The 10-100 TeV neutrinos expected from galactic SNRs (in particular from RX J1713.7-3946) targets of future underwater neutrino telescopes.

Costantini, M.L. [Universita dell'Aquila, L'Aquila (Italy); INFN, L'Aquila (Italy); Vissani, F. [Laboratori Nazionali del Gran Sasso, INFN, Assergi, AQ (Italy)

2005-10-12

38

Supernova and Gamma-Ray Burst Remnants  

Microsoft Academic Search

The connection between Supernovae and Gamma-Ray Bursts has provided insights to extend our understanding of both these phenomena beyond what was known from studying them separately. A unique window into the connections between the progenitors and mechanisms of supernova and gamma-ray burst explosions is provided by their remnants. This meeting brings together experts of the remnants of both Supernovae and

Roger Chevalier; Una Hwang; Martin Laming

2006-01-01

39

When will a pulsar in supernova 1987a be seen?  

PubMed

The means by which a pulsar might be detected in the remnant of supernova 1987a in the Large Magelanic Cloud is examined. One possibility is that the slower-than-radioactive decay typically seen in the type II light curves is itself the sign of powering by the underlying pulsar, with the decline representing not the spinning down of the pulsar but rather the declining nebular opacity that would allow increasing amounts of the energy to escape as gamma rays. The test of this hypothesis (if the supernova conforms to type II expectations) would be to look for the "missing" energy in the form of those gamma rays that escape from the remnant instead of powering it. PMID:17829358

Michel, F C; Kennel, C F; Fowler, W A

1987-11-13

40

Supernova Remnants and Molecular Clouds  

NASA Astrophysics Data System (ADS)

We review recent Infrared Space Observatory (ISO) and near-infrared observations of a number of supernova remnants, which are interacting with molecular clouds. Atomic fine-structure lines of [C II], [N II], [N III, [O I], [O II], [O III], [Si II], [P II], [Fe II], and two lines of shocked molecular hydrogen S(3) and S(9), were detected for three remnants using ISO. Virtually all existing atomic lines are detected. No single shock model can account for all of the observed lines, and to explain the detected lines requires both moderate ( 10^2cm-3) and high ( ~ 10^4cm-3) pre-shock densities. The inferred high density and warm temperatures are from heated dense clumps due to supernova shocks, and the principal coolants of radiative shocks are [O I] 63 µ and [Si II] 34.8 µ lines. Shock-excited far-infrared emission of H[2]O, OH, and CO is also detected, which is consistent with collisional excitation in warm, very dense ( 210^5cm-3) gas. We also took high-resolution images of molecular hydrogen and [Fe II] using ground-based observations, which reveal how shocks develop around clouds. Displacements between molecular hydrogen and [Fe II] structures are often observed, and the images show that a single primary shock is present on large scales. The possibility of star formation induced by supernova shocks when SN shocks interact with clouds is discussed.

Rho, J.; Reach, W.

2003-01-01

41

Cosmic Ray Acceleration in Supernova Remnants  

NASA Astrophysics Data System (ADS)

We review the main observational and theoretical facts about acceleration of Galactic cosmic rays in supernova remnants, discussing the arguments in favor and against a connection between cosmic rays and supernova remnants, the so-called supernova remnant paradigm for the origin of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of 1) magnetic field amplification, 2) acceleration of nuclei heavier than hydrogen, 3) presence of neutrals in the circumstellar environment. The status of the supernova-cosmic ray connection in the time of Fermi-LAT and Cherenkov telescopes is also discussed.

Blasi, P.

2011-06-01

42

Einstein Observations of Galactic supernova remnants  

SciTech Connect

This paper summarizes the observations of Galactic supernova remnants with the imaging detectors of the Einstein Observatory. X-ray surface brightness contours of 47 remnants are shown together with gray-scale pictures. Count rates for these remnants have been derived and are listed for the HRI, IPC, and MPC detectors. 118 refs.

Seward, F.D. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA))

1990-08-01

43

ANTIMATTER PRODUCTION IN SUPERNOVA REMNANTS  

SciTech Connect

We calculate the energy spectra of cosmic rays (CRs) and their secondaries produced in a supernova remnant (SNR) taking into account the time dependence of the SNR shock. We model the trajectories of charged particles as a random walk with a prescribed diffusion coefficient, accelerating the particles at each shock crossing. Secondary production by CRs colliding with gas is included as a Monte Carlo process. We find that SNRs produce less antimatter than suggested previously: the positron/electron ratio F{sub e}{sup +}/F{sub e}{sup +}{sub +e}{sup -} and the antiproton/proton ratio F{sub p-bar/}F{sub p-bar+p} are a few percent and few x 10{sup -5}, respectively. Moreover, the obtained positron/electron ratio decreases with energy, while the antiproton/proton ratio rises at most by a factor of two above 10 GeV.

Kachelriess, M.; Ostapchenko, S. [Institutt for fysikk, NTNU, Trondheim (Norway); Tomas, R. [II. Institut fuer Theoretische Physik, Universitaet Hamburg (Germany)

2011-06-01

44

Supernova remnants: the X-ray perspective  

NASA Astrophysics Data System (ADS)

Supernova remnants are beautiful astronomical objects that are also of high scientific interest, because they provide insights into supernova explosion mechanisms, and because they are the likely sources of Galactic cosmic rays. X-ray observations are an important means to study these objects. And in particular the advances made in X-ray imaging spectroscopy over the last two decades has greatly increased our knowledge about supernova remnants. It has made it possible to map the products of fresh nucleosynthesis, and resulted in the identification of regions near shock fronts that emit X-ray synchrotron radiation. Since X-ray synchrotron radiation requires 10-100 TeV electrons, which lose their energies rapidly, the study of X-ray synchrotron radiation has revealed those regions where active and rapid particle acceleration is taking place. In this text all the relevant aspects of X-ray emission from supernova remnants are reviewed and put into the context of supernova explosion properties and the physics and evolution of supernova remnants. The first half of this review has a more tutorial style and discusses the basics of supernova remnant physics and X-ray spectroscopy of the hot plasmas they contain. This includes hydrodynamics, shock heating, thermal conduction, radiation processes, non-equilibrium ionization, He-like ion triplet lines, and cosmic ray acceleration. The second half offers a review of the advances made in field of X-ray spectroscopy of supernova remnants during the last 15 year. This period coincides with the availability of X-ray imaging spectrometers. In addition, I discuss the results of high resolution X-ray spectroscopy with the Chandra and XMM-Newton gratings. Although these instruments are not ideal for studying extended sources, they nevertheless provided interesting results for a limited number of remnants. These results provide a glimpse of what may be achieved with future microcalorimeters that will be available on board future X-ray observatories. In discussing the results of the last 15 years I have chosen to discuss a few topics that are of particular interest. These include the properties of Type Ia supernova remnants, which appear to be regularly shaped and have stratified ejecta, in contrast to core collapse supernova remnants, which have patchy ejecta distributions. For core collapse supernova remnants I discuss the spatial distribution of fresh nucleosynthesis products, but also their properties in connection to the neutron stars they contain. For the mature supernova remnants I focus on the prototypal supernova remnants Vela and the Cygnus Loop. And I discuss the interesting class of mixed-morphology remnants. Many of these mature supernova remnants contain still plasma with enhanced ejecta abundances. Over the last five years it has also become clear that many mixed-morphology remnants contain plasma that is overionized. This is in contrast to most other supernova remnants, which contain underionized plasmas. This text ends with a review of X-ray synchrotron radiation from shock regions, which has made it clear that some form of magnetic-field amplification is operating near shocks, and is an indication of efficient cosmic-ray acceleration.

Vink, Jacco

2012-12-01

45

Progenitor's Signatures in Type Ia Supernova Remnants  

NASA Astrophysics Data System (ADS)

The remnants of Type Ia supernovae (SNe Ia) can provide important clues about their progenitor histories. We discuss two well-observed supernova remnants (SNRs) that are believed to have resulted from SNe Ia, and use various tools to shed light on the possible progenitor histories. We find that Kepler's SNR is consistent with a symbiotic binary progenitor consisting of a white dwarf and an AGB star. Our hydrosimulations can reproduce the observed kinematic and morphological properties. For Tycho's remnant we use the characteristics of the X-ray spectrum and kinematics to show that the ejecta has likely interacted with dense circumstellar gas.

Chiotellis, A.; Kosenko, D.; Schure, K. M.; Vink, J.

2013-01-01

46

The neutron star born in the Antlia supernova remnant  

NASA Astrophysics Data System (ADS)

Among all known young nearby neutron stars, we search for the neutron star that was born in the same supernova event that formed the Antlia supernova remnant (SNR). We also look for a runaway star that could have been the former companion to the neutron star (if it exists) and then got ejected due to the same supernova. We find the pulsar PSR J0630-2834 to be the best candidate for a common origin with the Antlia SNR. In that scenario, the SNR is ?1.2 Myr old and is presently located at a distance of ?138 pc. We consider the runaway star HIP 47155 a former companion candidate to PSR J0630-2834. The encounter time and place is consistent with both stars being ejected from the Antlia SNR. We measured the radial velocity of HIP 47155 as 32.42 0.70 km s-1.

Tetzlaff, N.; Torres, G.; Neuhuser, R.; Hohle, M. M.

2013-10-01

47

Submillisecond optical pulsar in supernova 1987A  

Microsoft Academic Search

An optical pulsar with frequency f = 1,968,629 Hz has been detected at the location of supernova 1987A in the LMC. The brightness of the pulsed light increased from magnitude 19 to 18 during a 7-hr observation period starting on 18.1 January 1987 UT. The frequency of the pulsar during this same period varied in a nearly sinusoidal manner, with

J. Kristian; C. R. Pennypacker; D. E. Morris; R. A. Muller; J. Middleditch; M. A. Hamuy; W. E. Kunkel; J. N. Imamura; R. Lucinio; T. Y. Steiman-Cameron; S. J. Rawlings; T. P. Sasseen; I. K. Shelton; I. R. Tuohy

1989-01-01

48

X-ray observations of two `unusual' Supernova Remnants: CTB80 containing the 40 millisecond pulsar PSR1951+32, and W50 containing the peculiar source SS433.  

NASA Astrophysics Data System (ADS)

{CTB 80} & {W50} are two `unusual' supernova remnants (SNRs) since unlike the other composite remnants, their radio morphology presents pronounced asymmetric structures. The `unusual' properties of these SNRs are to a large extent associated with the emission from the compact objects associated with them, and their X-ray emission is the key to a better understanding of their properties. I intend to present the X-ray analysis of these two peculiar sources and their powering engines. CTB 80 contains a 40 millisecond {isolated} pulsar, {PSR1951+32}, emitting non-thermal X-rays, and powering a compact nebula which is resolved with the ROSAT HRI. It has also a synchrotron nebula extending few arcminutes east of the pulsar and overlapping the radio plateau. With the ROSAT PSPC, a large <= 1(o) emission region is also detected in the hard energy band. W50, long thought to be the largest galactic SNR, contains at its center the mini-AGN {binary} source {SS433}, famous for its two-sided jets. I will present the X-ray analysis of the eastern and western lobes of W50 with both the ROSAT PSPC as well as the ASCA GIS detectors, thus covering the 0.1 -- 10 keV energy range. The emission is elongated along the axis of the precession cone of the SS433 jets, with an enhancement of brightness at ~ 35(') from SS433. The X-ray emission out to the base of the radio `ears' is characterized by a hard spectrum whose spectral parameters vary in the radial and lateral directions. With the ROSAT PSPC, there is also detection of a much softer X-ray emission coincident with the eastern radio `ear' at the interaction zone between the jets and the ambient medium. Using the above analysis and correlating the X-ray maps with those at other wavelengths, I discuss the possibility for these remnants to be partly or entirely produced by their powering engines, and derive some physical parameters relevant to better understand their nature.

Safi-Harb, S.

1996-12-01

49

Supernova Remnant 1987A at High Resolution  

Microsoft Academic Search

We present high resolution radio and X-ray observations of supernova remnant 1987A. VLBI imaging at 1.4 and 1.7 GHz taken in 2007 and 2008 with the Australian Long Baseline Array provides the highest resolution radio images of the remnant to date, revealing two extended lobes with an overall morphology consistent with observations at lower resolutions. We find evidence of small-scale

Chi-Yung Ng; T. M. Potter; L. Staveley-Smith; B. M. Gaensler; S. S. Murray; S. Tingay; C. Phillips; A. K. Tzioumis; G. Zanardo

2011-01-01

50

Fermi Proves Supernova Remnants Make Cosmic Rays  

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 protons interact with nearby interstellar gas clouds, which then emit gamma rays. Credit:NASA's Goddard Space Flight Center

gsfcvideo

2013-02-14

51

Infrared Spectroscopy and Imaging of Supernova Remnants.  

National Technical Information Service (NTIS)

The infrared spectrophotometry and line images of the Crab nebula and Cygnus loop supernova remnants, are presented. In the Crab the filaments have a Fe(II) 1.644 microns/Br gamma ratio value of 10 to 50. H2 emission is found in two filaments, confirming ...

J. R. Graham G. S. Wright A. J. Longmore

1989-01-01

52

Neutrino emission of Fermi supernova remnants  

NASA Astrophysics Data System (ADS)

The Fermi ?-ray space telescope reported the observation of several Galactic supernova remnants recently, with the ?-ray spectra well described by hadronic pp collisions. The possible neutrino emissions from these Fermi detected supernova remnants are discussed in this work, assuming the hadronic origin of the ?-ray emission. The muon event rates induced by the neutrinos from these supernova remnants on typical km 3 neutrino telescopes, such as the IceCube and the KM3NeT, are calculated. The results show that for most of these supernova remnants the neutrino signals are too weak to be detected by the on-going or up-coming neutrino experiment. Only for the TeV bright sources RX J1713.7-3946 and possibly W28 the neutrino signals can be comparable with the atmospheric background in the TeV region, if the protons can be accelerated to very high energies. The northern hemisphere based neutrino telescope might detect the neutrinos from these two sources.

Yuan, Qiang; Yin, Peng-Fei; Bi, Xiao-Jun

2011-08-01

53

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

54

Shock Acceleration Efficiency in Kepler's Supernova Remnant  

NASA Astrophysics Data System (ADS)

Fast shock waves like those in young supernova remnants put some fraction of their energy into fast particles, and another fraction into magnetic field. These fractions are not well determined typically, because synchrotron emission from relativistic electrons depends on roughly the product of the two, while the shock energy density depends on gas density and shock speed. Shock speeds can be difficult to determine from thermal X-ray spectra, as electrons and ions may have different temperatures, and significant energy may be lost to the fast particles. Most importantly, accurate thermal-gas densities are often unknown, or only roughly known from X-ray emission measures. All these quantities may vary at different locations in a supernova remnant. We present new determinations of gas densities at various points around the periphery of Kepler's supernova remnant, from modeling Spitzer IRS spectra from shock-heated dust. In combination with shock velocities from proper motions, radio brightnesses, and magnetic-field determinations from X-ray synchrotron morphology, we can then estimate the fractions of shock energy in relativistic electrons and in magnetic field, at different points around the remnant periphery. Furthermore, X-ray synchrotron emission visible around much of the periphery allows the determination of maximum electron energies. We present spatially resolved estimates of these quantities and discuss their significance for theoretical models of shock acceleration.

Reynolds, Stephen P.; Williams, B.; Borkowski, K.; Blair, W.; Ghavamian, P.; Long, K.; Sankrit, R.

2012-01-01

55

Antlia Supernova Remnant in Far-ultraviolet  

NASA Astrophysics Data System (ADS)

Antlia supernova remnant (l = 276.52, b = +19.05) was recently discovered by McCullough et al. (2002), and its angular size ( 24) is comparable to Monogem Ring. It shows a diffuse appearance in soft X-ray, which is anti-correlated with 100 ?m infrared emission and surrounded by annular enhancements in H?. We present the far-ultraviolet view of the remnant observed with Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR), also known as Far-ultraviolet IMaging Spectrograph (FIMS). C IV ? and Si II emission lines were detected in the remnant region, and their emission-line maps show a rough anti-correlation with a soft X-ray map (ROSAT All Sky Survey 0.25 keV map).

Shinn, Jong-Ho; Min, K. W.; Seon, K.; Lim, Y.; Edelstein, J.; Han, W.; Sankrit, R.; FIMS Team at KAIST; FIMS Team at KASI; SPEAR Team at SSL

2006-09-01

56

The Glast Mission and Observability of Supernovae Remnants  

NASA Astrophysics Data System (ADS)

The Gamma-ray Large Area Space Telescope (GLAST) is a collaboration of several countries: France, Germany, Italy, Japan, Sweden and United States of America. GLAST is a satellite-based observatory that will study the Cosmos in the Energy Range 10 keV - 300 GeV and consists of two different instruments: the Large Area Telescope (LAT) and the GLAST Burst Monitor (GBM). The two instruments are ready and now are being tested and integrated with the spacecraft: the launch is scheduled for October 2007. GLAST will improve the knowledge about several astrophysical sources (AGNs, Pulsars, GRBs, etc.). In this paper we will consider the scientific case of gamma-ray emitting Super-novae Remnants (SNRs).

Tibolla, Omar

2007-11-01

57

Supernova Remnant 1987A at High Resolution  

NASA Astrophysics Data System (ADS)

We present high resolution radio and X-ray observations of supernova remnant 1987A. VLBI imaging at 1.4 and 1.7 GHz taken in 2007 and 2008 with the Australian Long Baseline Array provides the highest resolution radio images of the remnant to date, revealing two extended lobes with an overall morphology consistent with observations at lower resolutions. We find evidence of small-scale features in the radio remnant, which possibly consist of discrete clumps near the inner surface of the shell. These features have spatial extent smaller than 0.2" and contribute less than 13% of the total remnant flux. We also report new X-ray observation taken in 2010 August with the High Resolution Camera onboard the Chandra X-ray Observatory. Comparing to the 2008 April exposure with the same instrument, the remnant flux increased by 43% in the 0.08-10 kev range and the relative brightness of the X-ray lobes around the shell show significant variability. In particular, the western half of shell is now 15% brighter than the eastern half. No central compact object is found in the radio and X-ray images. We compare the detection limits to previous studies and discuss the physical implications. The Australia Long Baseline Array is part of the Australia Telescope which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

Ng, Chi-Yung; Potter, T. M.; Staveley-Smith, L.; Gaensler, B. M.; Murray, S. S.; Tingay, S.; Phillips, C.; Tzioumis, A. K.; Zanardo, G.

2011-01-01

58

The Hubble Heritage Image of the Crab Nebula Supernova Remnant  

NASA Astrophysics Data System (ADS)

The Hubble Heritage Project has the aim of providing the public with pictorially striking images of celestial objects obtained with NASA's Hubble Space Telescope. Here we present a 5-color Wide Field Planetary Camera 2 (WFPC2) image of the Crab Nebula, a ~950 year old supernova remnant located 6500 light-years distant in the constellation Taurus. The images were obtained in 1995 January and April, and the science investigation reporting results was published by Blair, W. P., et al. (1997, ApJS, 109, 473--480). Over 10 hours of exposure time through 5 separate optical continuum band and emission-line filters were used to study size scales and ionization structures of the filaments and newly synthesized dust within the expanding ejecta. The Heritage version of these data shows several important aspects of the Crab Nebula all in one spectacular image. The continuum image shows stars, including the enigmatic pulsar (the collapsed core of the original star) and the ghostly diffuse synchrotron nebula energized by the pulsar. The synchrotron nebula in turn heats and ionizes the surrounding clumpy filaments of gas and dust visible in the emission line images. These filaments are the supernova ejecta that were expelled during the explosion and are now expanding outward from the pulsar at high speed. The different colors in the picture show optical emission lines of hydrogen (orange), nitrogen (red), sulfur (pink) and oxygen (bluish-green). The subtle changes in color from one filament to the next arise because of varying temperatures and densities of the gas, and variable chemical abundances of the ``star stuff," or the doppler shifting of emission into or out of the various narrow filter bandpasses. Support for this work was provided by NASA through grant numbers GO-07632.01-96A and GO-5354.04-93A from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

Blair, W. P.; English, J.; Bond, H. E.; Christian, C. A.; Frattare, L.; Hamilton, F.; Levay, Z.; Noll, K. S.

2000-05-01

59

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

60

Supernova remnants and the physics of strong shock waves  

Microsoft Academic Search

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

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

1994-01-01

61

Supernova remnants and their X-ray emission  

SciTech Connect

This book contains the proceedings from the International Astronomical Union Symposium No. 101 on supernova remnants. The proceedings contain a complete report on the effects of X-ray information on the ideas about supernova remnants. Also included are reviews of radio, optical, and theoretical results. The volume contains transcriptions of some of the discussions that followed the papers given at the symposium.

Danziger, J.; Gorenstein, P. (eds.)

1983-01-01

62

FERMI LARGE AREA TELESCOPE OBSERVATION OF SUPERNOVA REMNANT S147  

SciTech Connect

We present an analysis of gamma-ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope in the region around supernova remnant (SNR) S147 (G180.0-1.7). A spatially extended gamma-ray source detected in an energy range of 0.2-10 GeV is found to coincide with SNR S147. We confirm its spatial extension at >5{sigma} confidence level. The gamma-ray flux is (3.8 {+-} 0.6) Multiplication-Sign 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 Multiplication-Sign 10{sup 34} (d/1.3 kpc){sup 2} erg s{sup -1} in this energy range. The gamma-ray emission exhibits a possible spatial correlation with the prominent H{alpha} filaments of SNR S147. There is no indication that the gamma-ray emission comes from the associated pulsar PSR J0538+2817. The gamma-ray spectrum integrated over the remnant is likely dominated by the decay of neutral {pi} mesons produced through the proton-proton collisions in the filaments. The reacceleration of the pre-existing cosmic rays and subsequent adiabatic compression in the filaments is sufficient to provide the energy density required of high-energy protons.

Katsuta, J.; Uchiyama, Y.; Tanaka, T.; Tajima, H.; Bechtol, K.; Funk, S.; Lande, J. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Hanabata, Y. [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Lemoine-Goumard, M. [Universite Bordeaux 1, CNRS/IN2p3, Centre d'Etudes Nucleaires de Bordeaux Gradignan, 33175 Gradignan (France); Takahashi, T., E-mail: katsuta@slac.stanford.edu, E-mail: uchiyama@slac.stanford.edu [Institute of Space and Astronautical Science, Japanese Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

2012-06-20

63

The Evolution of Supernova Remnants in Different Galactic Environments, and Its Effects on Supernova Statistics.  

National Technical Information Service (NTIS)

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...

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

1980-01-01

64

Supernovae, their functioning, lightcurves, and remnants  

NASA Astrophysics Data System (ADS)

Ever since Shklovskii's influential 1962 paper, the literature tends to model supernovae (SNe) with strong shock waves (or blast waves), implying reverse shocks, Sedov stages, and the like. Here I repeat my conviction since 1988, that all SNe are of the core-collapse type, and are expelled by the collapsing core's wound-up magnetic field plus its decay product - an ultra-high-energy (UHE) relativistic cavity - which serves as the ultimate piston. The piston's Rayleigh-Taylor instability tears the ejected envelope into a huge number (?10 3) of (magnetized, filamentary) fragments, or splinters. The critical stellar mass Mcrit for core collapse to happen is closer to 5 M? than to 8 M?. SN remnants are former stellar windzones, collisionally heated when traversed by the shell of ejected SN splinters and by its relativistic piston (which has strongly cooled, though, via adiabatic expansion).

Kundt, Wolfgang

2008-10-01

65

Supernova remnants and the physics of strong shock waves  

NASA Astrophysics Data System (ADS)

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.; Wefel, John P.

1994-07-01

66

Generation of Cosmic rays in Historical Supernova Remnants  

NASA Astrophysics Data System (ADS)

We present the results of observations of two types of Galactic supernova remnants with the SHALON mirror Cherenkov telescope of Tien-Shan high-mountain Observatory: the shell-type supernova remnants Tycho, Cas A and IC 443; plerions Crab Nebula, 3c58(SN1181) and Geminga (probably plerion). The experimental data have confirmed the prediction of the theory about the hadronic generation mechanism of very high energy (800 GeV - 100 TeV) gamma-rays in Tycho's supernova remnant. The data obtainedsuggest that the very high energy gamma-ray emission in the objects being discussedis different in origin.

Sinitsyna, V. G.; Sinitsyna, V. Y.

2013-06-01

67

Cosmic ray acceleration in young supernova remnants  

NASA Astrophysics Data System (ADS)

We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 ?G the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

Schure, K. M.; Bell, A. R.

2013-10-01

68

Discovery of an Old, Nearby, and Overlooked Supernova Remnant Centered on the Southern Constellation Antlia Pneumatica  

NASA Astrophysics Data System (ADS)

We report the discovery of a supernova remnant (SNR) with an angular diameter of 24, centered on the southern constellation Antlia Pneumatica. The SNR is detected well in H? and X-rays. Within the Antlia SNR's outline, a marginally significant feature is detected in the 1.8 MeV gamma-ray line of the radioisotope 26Al. At an estimated distance dA~=60-340 pc, the Antlia SNR is perhaps the nearest SNR except for the Local Bubble. Consequently, any associated neutron star or black hole is expected to have a large proper motion. Of the trajectories of nearby pulsars with well-determined proper motions, only B0950+08's passes within the SNR outline. If the SNR and the pulsar B0950+08 indeed both originated from the same supernova, then their age t=1.8(dA/100 pc) Myr.

McCullough, P. R.; Fields, Brian D.; Pavlidou, Vasiliki

2002-09-01

69

Modelling the interaction of thermonuclear supernova remnants with circumstellar structures: the case of Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

The well-established Type Ia remnant of Tycho's supernova (SN 1572) reveals discrepant ambient medium-density estimates based on either the measured dynamics or the X-ray emission properties. This discrepancy can potentially be solved by assuming that the supernova remnant (SNR) shock initially moved through a stellar wind bubble, but is currently evolving in the uniform interstellar medium with a relatively low density. We investigate this scenario by combining hydrodynamical simulations of the wind-loss phase and the SNR evolution with a coupled X-ray emission model, which includes non-equilibrium ionization. For the explosion models we use the well-known W7 deflagration model and the delayed detonation model that was previously shown to provide good fits to the X-ray emission of Tycho's SNR. Our simulations confirm that a uniform ambient density cannot simultaneously reproduce the dynamical and X-ray emission properties of Tycho. In contrast, models that considered that the remnant was evolving in a dense, but small, wind bubble reproduce reasonably well both the measured X-ray emission spectrum and the expansion parameter of Tycho's SNR. Finally, we discuss possible mass-loss scenarios in the context of single- and double-degenerate models which possibly could form such a small dense wind bubble.

Chiotellis, A.; Kosenko, D.; Schure, K. M.; Vink, J.; Kaastra, J. S.

2013-10-01

70

Hidden old supernova remnants: prediction and discovery  

NASA Astrophysics Data System (ADS)

There are about 230 known supernova remnants (SNRs) in the Galaxy, most of which have been discovered in radio continuum and/or X-rays. This number is much less than what we would expect from the Galactic supernova rate and their life time. Presumably most old SNRs are not observable because of their faintness and background contamination. We propose a new method of discovering old SNRs; that is, by searching for HI 21cm emission line from shock-accelerated atomic gas. The emission has been detected toward the known SNRs and is seen as a faint, extended wing beyond the maximum or minimum velocities permitted by the Galactic rotation. We show that there are many similar features in large-scale (l,v) diagrams of the 21-cm emission in the Galactic plane which are not associated with known SNRs. We propose that such ``forbidden-velocity (FV)" wings could be candidates for heretofore unidentified old SNRs. We present high-resolution Arecibo HI 21-cm line image of one of these FV wings to show that it is an expanding shell, very likely a SNR shell. We also examine their statistical properties and compare them to our model calculation --- a calculation of the visibility of old SNRs in HI 21cm emission line in the Galaxy. The comparison suggests that the number of FV wings is much less than expected in the inner Galaxy if the interstellar space there is largely filled with the warm neutral medium of moderate density. We discuss the implications on the structure of the interstellar medium.

Koo, B.-C.; Kang, J.-H.

71

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

72

Nonthermal Radiation from Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

Most of high energy cosmic rays (CRs) are thought to be produced by diffusive shock acceleration (DSA) at supernova remnants (SNRs) within the Galaxy. Fortunately, nonthermal emissions from CR protons and electrons can provide direct observational evidence for such a model and place strong constraints on the complex nonlinear plasma processes in DSA theory. In this study we calculate the energy spectra of CR protons and electrons in Type Ia SNRs, using time-dependent DSA simulations that incorporate phenomenological models for some wave-particle interactions. We demonstrate that the timedependent evolution of the self-amplified magnetic fields, Alfvnic drift, and escape of the highest energy particles affect the energy spectra of accelerated protons and electrons, and so resulting nonthermal radiation spectrum. Especially, the spectral cutoffs in X-ray and γ-ray emission spectra are regulated by the evolution of the highest energy particles, which are injected at the early phase of SNRs. Thus detailed understandings of nonlinear wave-particle interactions and time-dependent DSA simulations of SNRs are crucial in testing the SNR hypothesis for the origin of Galactic cosmic rays.

Kang, Hyesung

2013-09-01

73

X-ray emission from supernova remnants  

SciTech Connect

This thesis deals with the x-ray spectra of supernova remnants (SNRs) and, in particular, the x-ray spectra of the two young Type I SNRs SN1006 and Tycho. An extensive grid of nonequilibrium model spectra of SNRs in the adiabatic blast wave stage of evolution is computed, and numerous diagnostics of the state and composition of the blast wave plasma are plotted over parameter space. It is demonstrated that the spectrum of an adiabatic blast wave is a good approximation to several other model SNR structures in which emission is dominated by gas undergoing quasi steady state ionization near a shock front, including the one-fluid isothermal blast wave similarity solution. None of these structures appears able to account for the observed spectra of SN1006 or Tycho. A new similarity solution for the early time evolution of uniform ejecta moving into an external medium is presented. It is argued that the x-ray spectra of SN1006 and Tycho are consistent with emission mainly from a reverse shock into 1.4 solar masses of initially uniform density SN ejecta consisting of pure heavy elements, moving into a uniform medium. Satisfactory fits to the observed spectra are obtained with a two layer structure of ejecta, an outer layer of unprocessed material, and an inner layer of mixed processed heavy elements. Various salient aspects of the physics of a shock-heated pure heavy element plasma are discussed.

Sackville Hamilton, A.J.

1985-01-01

74

Fermi acceleration at supernova remnant shocks  

NASA Astrophysics Data System (ADS)

We investigate the physics of particle acceleration at non-relativistic shocks exploiting two different and complementary approaches, namely a semi-analyticmodeling of cosmic-ray modified shocks and large hybrid (kinetic protons/fluid electrons) simulations. The former technique allows us to extract some information from the multi-wavelength observations of supernova remnants, especially in the ?-ray band, while the latter returns fundamental insights into the details of particle injection and magnetic field amplification via plasma instabilities. In particular, we present the results of large hybrid simulations of non-relativistic shocks, discussing the properties of the transition from the thermal to the non-thermal component, the spectrum of which turns out to be the power-law predicted by first-order Fermi acceleration. Along with a rather effective magnetic field amplification, we find that more than 20% of the bulk energy is converted in non-thermal particles, altering significantly the dynamics of the shock and leading to the formation of a precursor.

Caprioli, D.

2012-12-01

75

3D Simulations of Supernovae into the Young Remnant Phase  

NASA Astrophysics Data System (ADS)

The explosion of massive stars as core-collapse supernovae is an inherently three dimensional phenomenon. Observations of the young, ejecta dominated remnants of those explosions unambiguously demonstrate that asymmetry on large and small scales is the rule, rather than the exception. Numerical models of supernova remnants connect the observed remnants to models of the exploding stellar system and thus facilitate both improved interpretations of the observations as well as improve our understanding of the explosion mechanism. We present first 3D simulations of core- collapse supernovae evolving into supernova remnants calculated with SNSPH. The calculations were started from 1D collapsed models of 2 progenitor stars of different types, and follow the explosion from revival of the shock wave to shock break out in 3D. Two different interstellar media, a cold neutral medium and a dense molecular cloud, as well as a red supergiant stellar wind profile, were added to the explosion calculations shortly before shock breakout, so that the blast wave stays in the simulation. With this setup we can follow the dispersal of the nucleosynthesis products from the explosion into the Sedov stage of the supernova remnant evolution starting from realistic initial conditions for the supernova ejecta. We will present a first investigation in the mixing between stellar and interstellar matter as the supernova evolves into the young supernova remnant phase, and contrasts differences that are observed between the scenarios that are investigated. One of the goals is to distinguish between features that arose in instabilities during the explosion from those that were created in the interaction with the surrounding medium.

Ellinger, Carola I.; Young, P. A.; Fryer, C.; Rockefeller, G.; Park, S.

2013-01-01

76

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

NASA Astrophysics Data System (ADS)

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 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, A. D.; Wolfendale, A. W.

2013-09-01

77

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)

2006-02-13

78

Supernova Remnants, Cosmic Rays, and GLAST  

ScienceCinema

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.

79

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

80

HIGH-RESOLUTION X-RAY IMAGING OF SUPERNOVA REMNANT 1987A  

SciTech Connect

We report observations of the remnant of supernova 1987A with the High Resolution Camera (HRC) on board the Chandra X-ray Observatory. A direct image from the HRC resolves the annular structure of the X-ray remnant, confirming the morphology previously inferred by deconvolution of lower resolution data from the Advanced CCD Imaging Spectrometer. Detailed spatial modeling shows that a thin ring plus a thin shell gives statistically the best description of the overall remnant structure, and suggests an outer radius of 0.''96 +- 0.''05 +- 0.''03 for the X-ray-emitting region, with the two uncertainties corresponding to the statistical and systematic errors, respectively. This is very similar to the radius determined by a similar modeling technique for the radio shell at a comparable epoch, in contrast to previous claims that the remnant is 10%-15% smaller at X-rays than in the radio band. The HRC observations put a flux limit of 0.010 counts s{sup -1} (99% confidence level, 0.08-10 keV range) on any compact source at the remnant center. Assuming the same foreground neutral hydrogen column density as toward the remnant, this allows us to rule out an unobscured neutron star with surface temperature T {sup i}nfinity > 2.5 MK observed at infinity, a bright pulsar wind nebula or a magnetar.

Ng, C.-Y.; Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Murray, S. S.; Slane, P. O. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Park, S.; Burrows, D. N. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Staveley-Smith, L. [International Centre for Radio Astronomy Research, School of Physics, University of Western Australia, Crawley, WA 6009 (Australia); Manchester, R. N., E-mail: ncy@physics.usyd.edu.a [Australia Telescope National Facility, CSIRO, Marsfield, NSW 1710 (Australia)

2009-11-20

81

Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant  

NASA Astrophysics Data System (ADS)

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, although 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 toward the edge suggest that central emission is from evaporating cloudlets rather than thermal conduction in a more uniform, dense medium.

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

2007-12-01

82

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

83

Dust in historical Galactic Type Ia supernova remnants with Herschel  

NASA Astrophysics Data System (ADS)

The origin of interstellar dust in galaxies is poorly understood, particularly the relative contributions from supernovae and the cool stellar winds of low-intermediate-mass stars. Recently, large masses of newly formed dust have been discovered in the ejecta of core-collapse supernovae. Here, we present Herschel Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) photometry at 70-500 ?m of the historical, young supernova remnants: Kepler and Tycho, both thought to be the remnants of Type Ia explosion events. We detect a warm dust component in Kepler's remnant with ? and mass ?; this is spatially coincident with thermal X-ray emission and optical knots and filaments, consistent with the warm dust originating in the circumstellar material swept up by the primary blast wave of the remnant. Similarly for Tycho's remnant, we detect warm dust at ? with mass ?. Comparing the spatial distribution of the warm dust with X-rays from the ejecta and swept-up medium, and H? emission arising from the post-shock edge, we show that the warm dust is swept up interstellar material. We find no evidence of a cool (25-50 K) component of dust with mass ?0.07 M? as observed in core-collapse remnants of massive stars. Neither the warm or cold dust components detected here are spatially coincident with supernova ejecta material. We compare the lack of observed supernova dust with a theoretical model of dust formation in Type Ia remnants which predicts dust masses of 88(17) 10-3 M? for ejecta expanding into ambient surrounding densities of 1(5) cm-3. The model predicts that silicon- and carbon-rich dust grains will encounter, at most, the interior edge of the observed dust emission at 400 years, confirming that the majority of the warm dust originates from swept-up circumstellar or interstellar grains (for Kepler and Tycho, respectively). The lack of cold dust grains in the ejecta suggests that Type Ia remnants do not produce substantial quantities of iron-rich dust grains and has important consequences for the 'missing' iron mass observed in ejecta. Finally, although, we cannot completely rule out a small mass of freshly formed supernova dust, the Herschel observations confirm that significantly less dust forms in the ejecta of Type Ia supernovae than in the remnants of core-collapse explosions.

Gomez, H. L.; Clark, C. J. R.; Nozawa, T.; Krause, O.; Gomez, E. L.; Matsuura, M.; Barlow, M. J.; Besel, M.-A.; Dunne, L.; Gear, W. K.; Hargrave, P.; Henning, Th.; Ivison, R. J.; Sibthorpe, B.; Swinyard, B. M.; Wesson, R.

2012-03-01

84

Simulations of Mixed Morphology Supernova Remnants With Anisotropic Thermal Conduction  

Microsoft Academic Search

We explore the role of anisotropic thermal conduction on the evolution of\\u000asupernova remnants through interstellar media with a range of densities via\\u000anumerical simulations. We find that a remnant expanding in a dense environment\\u000acan produce centre-bright hard x-ray emission within 20 kyr, and centre-bright\\u000asoft x-ray emission within 60 kyr of the supernova event. In a more tenuous

David A. Tilley; Dinshaw S. Balsaraand; J. Christopher Howk

2006-01-01

85

Energy of Tycho's Supernova Remnant is increasing with time  

PubMed Central

It is shown, using the Zeldovich integral relations, that the energy of Tycho's Supernova Remnant is strongly growing with time, approximately as t1/3. This growth can be attributed to the exothermic reactions going inside the remnant. The use of the assumption of the adiabaticity of the motion inside of the shock front, and no losses or gain of energy at the front, seems therefore unjustified.

Barenblatt, Grigory Isaakovich

2008-01-01

86

Energy of Tycho's supernova remnant is increasing with time.  

PubMed

It is shown, using the Zeldovich integral relations, that the energy of Tycho's Supernova Remnant is strongly growing with time, approximately as t(1/3). This growth can be attributed to the exothermic reactions going inside the remnant. The use of the assumption of the adiabaticity of the motion inside of the shock front, and no losses or gain of energy at the front, seems therefore unjustified. PMID:18202174

Barenblatt, Grigory Isaakovich

2008-01-17

87

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

88

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

89

TYPING SUPERNOVA REMNANTS USING X-RAY LINE EMISSION MORPHOLOGIES  

SciTech Connect

We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in 17 Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse supernovae explosions are intrinsically more asymmetric.

Lopez, L. A.; Ramirez-Ruiz, E. [Department of Astronomy and Astrophysics, University of California Santa Cruz, 159 Interdisciplinary Sciences Building, 1156 High Street, Santa Cruz, CA 95064 (United States); Badenes, C. [Department of Astrophysical Sciences, Princeton University Peyton Hall, Ivy Lane, Princeton, NJ 08544 (United States); Huppenkothen, D. [Astronomical Institute, 'Anton Pannekoek', University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands); Jeltema, T. E. [UCO/Lick Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States); Pooley, D. A., E-mail: lopez@astro.ucsc.ed [Astronomy Department, University of Wisconsin, 475 North Charter Street, Madison, WI 53706 (United States)

2009-11-20

90

Asymmetric supernova explosions and the origin of binary pulsars  

Microsoft Academic Search

We investigate the effect of asymmetric supernova explosions on the orbital parameters of binary systems with a compact component. We relate such explosions to the origin of binary pulsars. The degree of asymmetry of the explosion is represented by the kick velocity gained by the exploding star due to the asymmetric mass ejection. The required kick velocity to produce the

W. Sutantyo

1978-01-01

91

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

NASA Astrophysics Data System (ADS)

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.

Badenes, Carles

2010-04-01

92

High-Velocity H I Gas in Supernova Remnants  

Microsoft Academic Search

Using the Hat Creek 85 foot telescope, we had carried out a survey of H I 21 cm emission lines toward all 103 known northern supernova remnants (SNRs) in order to find rapidly expanding SNR shells (Koo & Heiles 1991). We detected 15 SNRs that have associated high-velocity (HV) H I gas, most of which are quite likely the gas

Bon-Chul Koo

1993-01-01

93

Multiwavelength comparison of Cassiopeia A and Tycho's supernova remnant  

SciTech Connect

A comparison of high resolution radio, optical, and X-ray images of two young supernova remnants (SNR), Cas A and Tycho, shows significant differences between them, Cas A probably broke into many small knots at the time of the initial explosion, whereas Tycho's SNR appears to be a more uniformly expanding blast wave.

Dickel, J.R.; Murray, S.S.; Morris, J.; Wells, D.C.

1982-06-01

94

XMM-Newton observation of the Tycho supernova remnant  

Microsoft Academic Search

We present the observation of the Tycho supernova remnant obtained with the EPIC and RGS instruments onboard the XMM-Newton satellite. We compare images and azimuthally averaged radial profiles in emission lines from different elements (silicon and iron) and different transition lines of iron (Fe L and Fe K). While the Fe Xvii L line and Si Xiii K line images

A. Decourchelle; J. L. Sauvageot; M. Audard; B. Aschenbach; S. Sembay; R. Rothenflug; J. Ballet; T. Stadlbauer; R. G. West

2001-01-01

95

Some possible identification between Chinese guest stars and supernova remnants  

NASA Astrophysics Data System (ADS)

The relation between ancient guest stars (AGSs) and supernova remnants (SNRs) is studied. The AGSs and SNRs are compared in terms of visual position, distance, and age; the techniques used to calculate the parameters are described. Seven pairs of identifications between AGSs and SNRs were found and a list of the correlations is provided.

Wang, Z. R.; Liu, J. Y.; Gorenstein, P.; Zombeck, M. V.

96

Limits on an optical pulsar in supernova 1987A  

SciTech Connect

Since March 1987 the optical flux from supernova 1987A for periodic pulsations has been sought. As of August 1988, after 38 separate observations, no pulsar has been detected. The typical upper limit placed on the pulsed fraction optical light from the supernova is 0.0002, for pulse frequencies in the range 0.03-5000 Hz. The best limit on the pulsed fraction of supernova light is 7 x 10 to the -6th, on January 22, 1988. On August 28, 1988 the faintest limit for the magnitude of the pulsar, dimmer than 20th mag is reached. These limits are based on Fourier transforms of up to 67 million points, covering a range of spindown rates. 25 refs.

Pennypacker, C.R.; Morris, D.E.; Muller, R.A.; Perlmutter, S.; Kristian, J.A.; Middleditch, J.; Hamuy, M.A.; Kunkel, W.E.; Imamura, J.N.; Steiman-Cameron, T.Y. (California Univ., Berkeley (USA); Mount Wilson and Las Campanas Observatories, Pasadena, CA (USA); Los Alamos National Laboratory, NM (USA); Observatorio Interamericano de Cerro Tololo, La Serena (Chile); Oregon Univ., Eugene (USA); NASA, Ames Research Center, Moffett Field, CA (USA))

1989-05-01

97

Simulating Anisotropic Thermal Conduction in Supernova Remnants I : Numerics and the Evolution of Remnants  

Microsoft Academic Search

Anisotropic thermal conduction plays an important role in various astrophysical systems. One of the most stringent tests of thermal conduction can be found in supernova remnants. In this paper we study anisotropic thermal conduction and examine the physical nature of the flux of thermal conduction in the classical and saturated limits. We also present a temporally second-order accurate implicit-explicit scheme

D. S. Balsara; D. A. Tilley; J. C. Howk

2006-01-01

98

First VLBI Detection of the Radio Remnant of Supernova 1987A: Evidence for Small-scale Features  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the first very long baseline interferometry (VLBI) detection of the radio remnant of supernova 1987A. The VLBI data taken in 2007 and 2008 at 1.4 and 1.7 GHz, respectively, provide images sensitive to angular scales from 0farcs1 to 0farcs7, the highest resolution to date at radio frequencies. The results reveal two extended lobes with an overall morphology consistent with observations at lower resolutions. We find evidence of small-scale features in the radio shell, which possibly consist of compact clumps near the inner surface of the shell. These features have angular extent smaller than 0farcs2 and contribute less than 13% of the total remnant flux density. No central source is detected in the VLBI images. We place a 3? flux density limit of 0.3 mJy on any pulsar or pulsar wind nebula at 1.7 GHz.

Ng, C.-Y.; Potter, T. M.; Staveley-Smith, L.; Tingay, S.; Gaensler, B. M.; Phillips, C.; Tzioumis, A. K.; Zanardo, G.

2011-02-01

99

FIRST VLBI DETECTION OF THE RADIO REMNANT OF SUPERNOVA 1987A: EVIDENCE FOR SMALL-SCALE FEATURES  

SciTech Connect

We present a detailed analysis of the first very long baseline interferometry (VLBI) detection of the radio remnant of supernova 1987A. The VLBI data taken in 2007 and 2008 at 1.4 and 1.7 GHz, respectively, provide images sensitive to angular scales from 0.''1 to 0.''7, the highest resolution to date at radio frequencies. The results reveal two extended lobes with an overall morphology consistent with observations at lower resolutions. We find evidence of small-scale features in the radio shell, which possibly consist of compact clumps near the inner surface of the shell. These features have angular extent smaller than 0.''2 and contribute less than 13% of the total remnant flux density. No central source is detected in the VLBI images. We place a 3{sigma} flux density limit of 0.3 mJy on any pulsar or pulsar wind nebula at 1.7 GHz.

Ng, C.-Y. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); Potter, T. M.; Staveley-Smith, L.; Zanardo, G. [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, Crawley, WA 6009 (Australia); Tingay, S. [ICRAR, Curtin University, Bentley, WA 6102 (Australia); Gaensler, B. M. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Phillips, C.; Tzioumis, A. K., E-mail: ncy@hep.physics.mcgill.ca [Australia Telescope National Facility, CSIRO, Marsfield, NSW 1710 (Australia)

2011-02-10

100

Mechanism for strong shock electron heating in supernova remnants  

SciTech Connect

It is shown that collisionless shock waves propagating away from a supernova may be directly responsible for the 10 keV X-ray emission seen in supernova remnants. A sequence of plasma instabilities (Buneman and ion acoustic) between the reflected and/or transmitted ions and the background electrons at the foot of the shock front can give rise to rapid anomalous heating of electrons. Hybrid simulations of a perpendicular collisionless shock are presented to demonstrate that this heating can arise within a self-consistently computed shock structure. 15 references.

Cargill, P.J.; Papadopoulos, K.

1988-06-01

101

Optical Pulsar in the Large Magellanic Cloud Remnant 0540-69.3.  

National Technical Information Service (NTIS)

We have detected pulsed optical emission from the Large Magellanic Cloud (LMC) X-ray pulsar PSR 0540-693 (Seward et al. 1984). The pulsed emission has a time averaged magnitude of approximately 22.7. The X-ray pulsar was discovered in the LMC remnant, 054...

J. Middleditch C. R. Pennypacker

1984-01-01

102

DENSE IRON EJECTA AND CORE-COLLAPSE SUPERNOVA EXPLOSION IN THE YOUNG SUPERNOVA REMNANT G11.2-0.3  

SciTech Connect

We present the results of near-infrared spectroscopic observations of dense ({approx}>10{sup 3} cm{sup -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 1000 km s{sup -1}, while three western knots have relatively small blueshifts of 20-60 km s{sup -1}. This velocity discrepancy may indicate that the western knots have been significantly decelerated or that there exists a systematic velocity difference among the knots. One ejecta filament in the northwestern boundary, on the other hand, is redshifted by {approx}>200 km s{sup -1}, while opposite filament in the southeastern boundary shows a negligible radial motion. Some of the knots and filaments have secondary velocity components, and one knot shows a bow shock-like feature in the velocity structure. The iron ejecta appear to be devoid of strong emission from other heavy elements, such as S, which may attest to the alpha-rich freezeout process in the explosive nucleosynthesis of the core-collapse supernova explosion close to its center. The prominent bipolar distribution of the Fe ejecta in the northwestern and southeastern direction, along with the elongation of the central pulsar wind nebula in the perpendicular direction, is consistent with the interpretation that the supernova exploded primarily along the northwestern and southeastern direction.

Moon, Dae-Sik [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Koo, Bon-Chul; Seok, Ji Yeon [School of Physics and Astronomy, Seoul National University, Seoul, 151-742 (Korea, Republic of); Lee, Ho-Gyu [Department of Astronomy, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Matthews, Keith [Division of Physics, Mathematics and Astronomy, California Institute of Technology, MS 320-47, Pasadena, CA 91125 (United States); Lee, Jae-Joon [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Pyo, Tae-Soo; Hayashi, Masahiko, E-mail: moon@astro.utoronto.c [Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720 (United States)

2009-09-20

103

Fermi LAT Observations of Supernova Remnants Interacting with Molecular Clouds  

NASA Astrophysics Data System (ADS)

We report the detection of ?-ray emission coincident with four supernova remnants (SNRs) using data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. G349.7+0.2, CTB 37A, 3C 391 and G8.7-0.1 are supernova remnants known to be interacting with molecular clouds, as evidenced by observations of hydroxyl (OH) maser emission at 1720 MHz in their directions. SNR shocks are expected to be sites of cosmic rays acceleration, and clouds of dense material can provide effective targets for production of ?-rays from ? 0 decay. The observations reveal unresolved sources in the direction of G349.7+0.2, CTB 37A and 3C 391, and a possibly extended source coincident with G8.7-0.1, all with significance levels greater than 10?.

Castro, Daniel; Slane, Patrick

104

Supernova remnants in the central starburst region of M82  

Microsoft Academic Search

Global VLBI observations of the central kiloparsec of M82 at 1.6 GHz, attaining an angular resolution of 4 mas, were made on 3 Mar 2005. We present detailed images of four of the brightest, most compact supernova remnants as seen in these observations. These data are the fifth epoch of 1.6-GHz VLBI observations of M82, the first of which was

Danielle Fenech; T. W. B. Muxlow; R. J. Beswick; A. Pedlar; M. K. Argo; W. M. Trotman

2006-01-01

105

Supernova Remnant W-44: Observations at 8350 Megacycles per Second  

Microsoft Academic Search

The region of W-44 was mapped at 8350 megacycles per second. The degree of linear polarization of the most intense portion of W-44 integrated over the 10.8-minute-of-arc beam was 11 2 percent at position angle 45 degrees 5 degrees. This high degree of polarization is further evidence that W-44 is a supernova remnant. The integrated flux density of

J. P. Hollinger; R. W. Hobbs

1966-01-01

106

Observations of TeV Gamma Rays from Supernova Remnants  

NASA Astrophysics Data System (ADS)

Measurements of the gamma ray flux from a number of supernova remnants (SNRs) at energies above 250 GeV have been made with the Whipple Imaging air \\v Cerenkov detector. Observation of the gamma ray emission of SNRs at energies above 1 GeV should provide a sensitive test of shock acceleration models of particle acceleration in SNRs. Gamma-ray luminosities of supernova remnants are well constrained by the observed supernova rate and the cosmic ray flux if supernovae are indeed the source of cosmic rays. Drury et al. (Astron. Astrophys. 287, 959 (1994)) predict that the luminosity of nearby Sedov-phase SNRs should be observable by the Whipple telescope. In this model, diffusive shock acceleration produces energetic charged particles which interact with the ambient medium forming gamma rays. There is an indication that a number of unidentified EGRET sources may correspond to supernova remnants (G. Kanbach, private communication), although at these energies (>100 MeV) the diffuse background is somewhat uncertain. Measurements of the gamma-ray flux with the Whipple instrument have a similar sensitivity to the EGRET detector for a source spectral index of 2.15, and less sensitivity to diffuse background. A number of observations of SNRs including: Tycho, W66, IC443, and others have been made. Currently for Tycho an upper limit of 9times 10(-12) cm(-2) sec(-1) is obtained. The status of these observations will be presented, and it will be shown that these measurements combined with the EGRET observations are beginning to provide a useful constraint on models of cosmic ray origin. Gamma-ray observations may also be used to constrain models of particle acceleration in SNRs exhibiting pulser-powered synchrotron nebula (plerions). The status of observations of this class of objects, including the Crab nebula, will also be presented. Supported in part by the U.S. Dept. of Energy.

Buckley, James H.

1994-12-01

107

Very high-resolution observations of compact radio sources in the directions of supernova remnants  

Microsoft Academic Search

Compact radio sources whose positions lie within the outlines of supernova remnants may be the stellar remnants of supernova explosions and, if they are related to the supernova remnants, may be used to explore the nature of any morphological connection between the Galactic and extragalactic radio sources. Three such compact sources, G 127.11+0.54, CL 4, and 2051+433, have been observed

B. J. Geldzahler; D. B. Shaffer

1981-01-01

108

Simulating Anisotropic Thermal Conduction in Supernova Remnants I : Numerics and the Evolution of Remnants  

Microsoft Academic Search

Anisotropic thermal conduction plays an important role in various\\u000aastrophysical systems. One of the most stringent tests of thermal conduction\\u000acan be found in supernova remnants. In this paper we study anisotropic thermal\\u000aconduction and examine the physical nature of the flux of thermal conduction in\\u000athe classical and saturated limits. We also present a temporally second-order\\u000aaccurate implicit-explicit scheme

Dinshaw S. Balsara; David A. Tilley; J. Christopher Howk

2006-01-01

109

X-RAY MEASURED DYNAMICS OF TYCHO'S SUPERNOVA REMNANT  

SciTech Connect

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{sup -1} (expansion index m = 0.33, where R = t{sup m} ) to 0.''40 yr{sup -1} (m = 0.65) with azimuthal angle in 2000-2007 measurements, and 0.''14 yr{sup -1} (m = 0.26) to 0.''40 yr{sup -1} (m = 0.65) in 2003-2007 measurements. The azimuthal variation of the proper motion and the average expansion index of approx0.5 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{sup -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 approx<0.2 cm{sup -3}.

Katsuda, Satoru; Petre, Robert; Hwang, Una [Code 662, 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 08854-8019 (United States); Yamaguchi, Hiroya; Hayato, Asami [RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Mori, Koji [Faculty of Engineering, Department of Applied Physics, University of Miyazaki, 1-1 Gakuen Kibana-dai Nishi, Miyazaki 889-2192 (Japan); Tsunemi, Hiroshi, E-mail: Satoru.Katsuda@nasa.go, E-mail: Robert.Petre-1@nasa.go, E-mail: Una.Hwang-1@nasa.go, E-mail: jackph@physics.rutgers.ed, E-mail: hiroya@crab.riken.j, E-mail: hayato@crab.riken.j, E-mail: mori@astro.miyazaki-u.ac.j, E-mail: tsunemi@ess.sci.osaka-u.ac.j [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)

2010-02-01

110

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

111

Gamma rays from cosmic rays in supernova remnants  

NASA Astrophysics Data System (ADS)

Context. Cosmic rays are thought to be accelerated at supernova remnant (SNR) shocks, but obtaining conclusive evidence for this hypothesis is difficult. Aims: New data from ground-based ?-ray telescopes and the Large Area Telescope on the Fermi Gamma-ray Space Telescope are used to test this hypothesis. A simple model for ?-ray production efficiency is compared with measured ?-ray luminosities of SNRs, and the GeV to TeV fluxes ratios of SNRs are examined for correlations with SNR ages. Methods: The supernova explosion is modeled as an expanding spherical shell of material that sweeps up matter from the surrounding interstellar medium (ISM). The accumulated kinetic energy of the shell, which provides the energy available for nonthermal particle acceleration, changes when matter is swept up from the ISM and the SNR shell decelerates. A fraction of this energy is assumed to be converted into the energy of cosmic-ray electrons or protons. Three different particle radiation processes - nuclear pion-production interactions, nonthermal electron bremsstrahlung, and Compton scattering - are considered. Results: The efficiencies for ?-ray production by these three processes are compared with ?-ray luminosities of SNRs. Our results suggest that SNRs become less ?-ray luminous at ?104 yr, and are consistent with the hypothesis that supernova remnants accelerate cosmic rays with an efficiency of ?10% for the dissipation of kinetic energy into nonthermal cosmic rays. Weak evidence for an increasing GeV to TeV flux ratio with SNR age is found.

Dermer, C. D.; Powale, G.

2013-05-01

112

Annihilation emission from young supernova remnants  

NASA Astrophysics Data System (ADS)

Context. A promising source of the positrons that contribute through annihilation to the diffuse Galactic 511 keV emission is the ?+-decay of unstable nuclei like 56Ni and 44Ti synthesised by massive stars and supernovae. Although a large fraction of these positrons annihilate in the ejecta of SNe/SNRs, no point-source of annihilation radiation appears in the INTEGRAL/SPI map of the 511 keV emission. Aims: We exploit the absence of detectable annihilation emission from young local SNe/SNRs to derive constraints on the transport of MeV positrons inside SN/SNR ejecta and their escape into the CSM/ISM, both aspects being crucial to the understanding of the observed Galactic 511 keV emission. Methods: We simulated 511 keV lightcurves resulting from the annihilation of the decay positrons of 56Ni and 44Ti in SNe/SNRs and their surroundings using a simple model. We computed specific 511 keV lightcurves for Cas A, Tycho, Kepler, SN1006, G1.9+0.3 and SN1987A, and compared these to the upper-limits derived from INTEGRAL/SPI observations. Results: The predicted 511 keV signals from positrons annihilating in the ejecta are below the sensitivity of the SPI instrument by several orders of magnitude, but the predicted 511 keV signals for positrons escaping the ejecta and annihilating in the surrounding medium allowed to derive upper-limits on the positron escape fraction of ~13% for Cas A, ~12% for Tycho, ~30% for Kepler and ~33% for SN1006. Conclusions: The transport of ~MeV positrons inside SNe/SNRs cannot be constrained from current observations of the 511 keV emission from these objects, but the limits obtained on their escape fraction are consistent with a nucleosynthesis origin of the positrons that give rise to the diffuse Galactic 511 keV emission.

Martin, P.; Vink, J.; Jiraskova, S.; Jean, P.; Diehl, R.

2010-09-01

113

Constraints on fast ejecta in the Crab supernova remnant from optical spectral lines  

NASA Astrophysics Data System (ADS)

The low kinetic energy and mass of the Crab supernova remnant challenge our understanding of core-collapse supernova explosions. A possibility is that the Crab nebula is surrounded by a shell of fast ejecta containing the missing kinetic energy and mass. The only direct evidence for such a fast shell comes from an absorption feature in the Crab pulsar spectrum as a result of C IV?1550. The velocities inferred from the C IV line absorption extend to at least 2500 km s-1, which is about twice as fast as the expansion of main shell of the remnant in our direction. We have searched for additional evidence of fast-moving ejecta in the optical spectra obtained with the FORS1 instrument at the European Southern Observatory (ESO) 8.2-m Very Large Telescope (VLT) and with the Andalucia Faint Object Spectrograph and Camera (ALFOSC) at the 2.56-m Nordic Optical Telescope (NOT), with the focus on absorption in Ca II??3934,3968, and emission components in [O III] ??4959,5007. The data are compared with the C IV?1550 absorption, and with theoretical expectations derived from shell models with ballistic gas motion, and a power-law density profile of the fast ejecta. Along the line of sight to the pulsar, we find that no gas in the nebula moves faster towards us than ?1400 km s-1. We identify this gas as part of the known main shell of the remnant. This velocity agrees with previous results showing that the Crab nebula is moving slowly in this direction. It is slower than the velocity of 1680 km s-1 used in the models of Sollerman et al. as a minimum velocity of the presumed fast shell of supernova ejecta to account for the C IV line absorption. We find faster moving gas within 3-10 arcsec north and south of the pulsar, where the fastest gas moving towards us, as traced by [O III], has a velocity of 1650-1700 km s-1. The fastest [O III] emitting gas along the line of sight to the pulsar, on the rear side of the nebula, has a velocity of ?+1800 km s-1, which is higher than the velocity previously recorded for that direction. However, neither the [O III] nor Ca II lines display any signatures of fast shell ejecta at the velocities inferred from the C IV line absorption. To fully rule out the possibility that a chimney-like structure directed towards us could be responsible for the C IV line absorption, we need deep observations taken with 8-10-m class telescopes with good spectral resolution. We show that a spectral resolution better than 200 km s-1 is needed to draw any conclusions on emission lines from gas moving towards us, along the line of sight of the pulsar, faster than ?1700 km s-1. To probe the fast shell ejecta, new observations from the Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) should be substantially more powerful than the previous HST Space Telescope Imaging Spectrograph (STIS) data to fully explore the C IV?1550 absorption-line profile.

Lundqvist, P.; Tziamtzis, A.

2012-06-01

114

Evidence of X-ray Synchrotron Emission from Electrons Accelerated to 10(13) eV in the Cassiopeia A Supernova Remnant  

Microsoft Academic Search

The 2-60 keV X-ray spectrum of the Cassiopeia A supernova remnant has been measured using the Rossi X-ray Timing Explorer. This spectrum clearly reveals a nonthermal high-energy X-ray ``tail.'' A timing analysis of this data does not show evidence of pulsations at frequencies between about 10(-3) Hz and 1024 Hz. Of the possible nonthermal continuum emission mechanisms---a pulsar, inverse Compton

G. E. Allen; E. V. Gotthelf; K. Jahoda; J. Keohane; R. Petre; R. E. Lingenfelter; R. E. Rothschild

1997-01-01

115

Anomalous Radio Quiet Zones in X-ray Bright Young Supernova Remnants G54.1+0.3 and 3C58  

Microsoft Academic Search

We present analyses of the young, Crab-like supernova remnants (SNRs) G54.1+0.3 and 3C58 in the X-ray and radio wavelength regions using public data from the Chandra X-Ray Observatory and the Very Large Array. By overlaying the X-ray and radio images, we discover similar anomalous radio quiet point sources in each object that are slightly offset from the X-ray pulsar (

J. Z. Chen; S. J. Massenburg; G. A. Wolpert; J. W. Keohane; C. M. Olbert; C. R. Clearfield

2002-01-01

116

ASYMMETRIES IN THE EXPANSION AND EMISSION FROM YOUNG SUPERNOVA REMNANTS  

SciTech Connect

We present two-dimensional and three-dimensional numerical simulations of asymmetric young supernova remnants (SNRs) carried out with the hydrodynamical code YGUAZU, aiming to quantitatively assess the role of different factors that may give origin to such asymmetries in their expansion. In particular, we are interested in modeling the morphology of Tycho's SNR to address whether the companion star of a Type Ia supernova progenitor has played a role in the subsequent evolution of the remnant. With the results from the numerical simulations, we can not only study the morphology of the SNR but also compute the emission of the remnant in different spectral bands. In particular, we simulate X-ray maps, which can be directly compared to recent and previous observations of Tycho's SNR. Our results suggest that the most likely explanation for Tycho's morphology is that after the supernova (SN) explosion the shock front stripped the envelope of its companion. We represent this effect by adding a conical region with an enhanced density into the initial sphere immediately after the explosion. Assuming that Tycho's companion was a massive red giant star, we explore different values of the angle of aperture and mass excess of the conical region. A good agreement with observational data was found for the model with a mass excess of 0.3 M{sub sun} and an aperture of 90{sup 0}. After the collision with the SN shock wave, the companion would become an He-rich star. This scenario would gain observational support if a star with these characteristics is found in the vicinity of the center of the SN explosion.

Vigh, Carlos D.; Gomez, Daniel O.; Reynoso, Estela M. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales de la Universidad de Buenos Aires, Buenos Aires (Argentina); Velazquez, Pablo F.; Esquivel, Alejandro; Schneiter, E. Matias, E-mail: carlos@iafe.uba.ar, E-mail: gomez@iafe.uba.ar, E-mail: ereynoso@iafe.uba.ar, E-mail: pablo@nucleares.unam.mx, E-mail: esquivel@nucleares.unam.mx, E-mail: mschneiter@gmail.com [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-543, CP 04510, Mexico D.F. (Mexico)

2011-01-20

117

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

118

Cosmic-ray acceleration and escape from supernova remnants  

NASA Astrophysics Data System (ADS)

Galactic cosmic-ray (CR) acceleration to the knee in the spectrum at a few PeV is only possible if the magnetic field ahead of a supernova remnant (SNR) shock is strongly amplified by CRs escaping the SNR. A model formulated in terms of the electric charge carried by escaping CRs predicts the maximum CR energy and the energy spectrum of CRs released into the surrounding medium. We find that historical SNRs such as Cas A, Tycho and Kepler may be expanding too slowly to accelerate CRs to the knee at the present time.

Bell, A. R.; Schure, K. M.; Reville, B.; Giacinti, G.

2013-05-01

119

Azimuthal Density Variations around the Rim of Tycho's Supernova Remnant  

NASA Astrophysics Data System (ADS)

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 ~100 K in the post-shock environment by collisions with energetic electrons and ions. The ratio of the 70 to 24 ?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 (~0.1-0.2 cm-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 ~0.2 cm-3. Such preshock densities are obtained for highly (gsim 50%) porous ISM grains.

Williams, Brian J.; Borkowski, Kazimierz J.; Ghavamian, Parviz; Hewitt, John W.; Mao, S. Alwin; Petre, Robert; Reynolds, Stephen P.; Blondin, John M.

2013-06-01

120

Shocks in Dense Clouds in the Vela Supernova Remnant: FUSE  

NASA Astrophysics Data System (ADS)

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

2002-03-01

121

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

122

A Chandra ACIS Study of 30 Doradus. I. Superbubbles and Supernova Remnants  

NASA Astrophysics Data System (ADS)

We present an X-ray tour of diffuse emission in the 30 Doradus star-forming complex in the Large Magellanic Cloud using high spatial resolution X-ray images and spatially resolved spectra obtained with the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. The dominant X-ray feature of the 30 Doradus nebula is the intricate network of diffuse emission generated by interacting stellar winds and supernovae working together to create vast superbubbles filled with hot plasma. We construct maps of the region showing variations in plasma temperature (T=3-9 million degrees), absorption [NH=(1-6)1021 cm-2], and absorption-corrected X-ray surface brightness [SX=(3-126)1031 ergs s-1 pc-2]. Enhanced images reveal the pulsar wind nebula in the composite supernova remnant N157B, and the Chandra data show spectral evolution from nonthermal synchrotron emission in the N157B core to a thermal plasma in its outer regions. In a companion paper we show that R136, the central massive star cluster, is resolved at the arcsecond level into almost 100 X-ray sources. Through X-ray studies of 30 Doradus the complete life cycle of such a massive stellar cluster can be revealed.

Townsley, Leisa K.; Broos, Patrick S.; Feigelson, Eric D.; Brandl, Bernhard R.; Chu, You-Hua; Garmire, Gordon P.; Pavlov, George G.

2006-04-01

123

The theory of synchrotron emission from supernova remnants  

NASA Astrophysics Data System (ADS)

The time-dependent nonlinear kinetic theory for cosmic ray (CR) acceleration in supernova remnants (SNRs) is applied studying the properties of the synchrotron emission from SNRs, in particular, the surface brightness-diameter (?-D) relation. Detailed numerical calculations are performed for the expected range of the relevant physical parameters, namely the ambient density and the supernova explosion energy. The magnetic field in SNRs is assumed to be significantly amplified by the efficiently accelerating nuclear CR component. Due to the growing number of accelerated CRs the expected SNR luminosity increases during the free expansion phase, reaches a peak value at the beginning of the Sedov phase and then decreases again, since in this stage the overall CR number remains nearly constant, whereas the effective magnetic field diminishes with time. The theoretically predicted brightness-diameter relation in the radio range in the Sedov phase is close to ?R? D-17/4. It fits the observational data in a very satisfactory way. The observed spread of ?R at a given SNR size D is the result of the spread of supernova explosion energies and interstellar medium densities. Appendix is only available in electronic form at http://www.edpsciences.org

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

2004-11-01

124

The Interstellar Medium around the Supernova Remnant G320.4-1.2  

NASA Astrophysics Data System (ADS)

Using the Australia Telescope Compact Array, we have carried out a survey of the H I emission in the direction of the barrel-shaped supernova remnant (SNR) G320.4-1.2 (MSH 15-52) and its associated young pulsar B1509-58. The angular resolution of the data is 4.0?2.7?, and the rms noise is of order 30 mJy beam-1 (~0.5 K). The H I observations indicate that the north-northwest radio limb has encountered a dense H I filament (density ~12 cm-3) at the same LSR velocity as that of the SNR (VLSR~-68 km s-1). This H I concentration would be responsible for the flattened shape of the northwestern lobe of G320.4-1.2 and for the formation of the radio-optical-X-ray nebula RCW 89. The emission associated with the bright knots in the interior of RCW 89 can be explained as arising from the interaction between the collimated relativistic outflow from the pulsar and the denser part of this H I filament (density ~15 cm-3). The south-southeastern half of the SNR, on the other hand, seems to have rapidly expanded across a lower density environment (density ~0.4 cm-3). The H I data also reveal an unusual H I feature aligned with a collimated outflow generated by the pulsar, suggestive of association with the SNR. The anomalous kinematical velocity of this feature (VLSR~15 km s-1), however, is difficult to explain.

Dubner, G. M.; Gaensler, B. M.; Giacani, E. B.; Goss, W. M.; Green, A. J.

2002-01-01

125

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

126

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

127

Numerical Study of the Vishniac Instability in Supernova Remnants  

NASA Astrophysics Data System (ADS)

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, ?, and three distinct values are taken for the cavity (?1), the shell (?2), and the ISM (?3) with the condition ?2 < ?1, ?3. This low value of ?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.

2012-11-01

128

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

129

Spin Tilts in the Double Pulsar Reveal Supernova Spin Angular-momentum Production  

NASA Astrophysics Data System (ADS)

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; Lyutikov, Maxim; Kalogera, Vassiliki

2011-12-01

130

H I ABSORPTION SPECTRA TOWARD MAGPIS SUPERNOVA REMNANT CANDIDATES  

SciTech Connect

The Multi-Array Galactic Plane Imaging Survey is an ongoing project to map out the northern Galactic plane in the 21 cm radio continuum. The survey identified 30 probable supernova remnant candidates in the Galactic plane from 18 deg.

Johanson, A. K.; Kerton, C. R. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)], E-mail: akj18@iastate.edu, E-mail: kerton@iastate.edu

2009-12-15

131

ICPP: Collisionless shock and supernova remnant simulation experiments on VULCAN.  

NASA Astrophysics Data System (ADS)

The VULCAN laser at the Central Laser Facility is used for laboratory-based simulations of collisionless shocks. One of the most difficult aspects of collisionless shock behaviour, the role of the magnetic field, is to be tested directly against experiment. Preliminary experiments to generate strong magnetic fields using a laser-driven mm-scale Helmholtz coil, and the formation of collisionless colliding plasmas using two counter-streaming exploding foil plasmas will be discussed. We consider the scaling of the hydrodynamics and magnetic field of the these experiments to those in supernova remnants (SNR) impacting the interstellar medium (ISM). This is achieved by ensuring the experiment and the SNR-ISM exhibit similar values of key dimensionless parameters. Work supported in part by EPSRC, CLF Direct Access, CEC-ERB FMR XCT 980168, Euratom and the UK DTI.

Woolsey, Nigel C.

2000-10-01

132

NON-MAXWELLIAN Halpha PROFILES IN TYCHO'S SUPERNOVA REMNANT  

SciTech Connect

The broad components of the Halpha lines in most non-radiative shocks can be fit with single-Gaussian components. We have obtained a high-quality spectrum of a position in Tycho's supernova remnant with the MMT and Blue Channel Spectrograph which shows, for the first time, that a single Gaussian does not provide an acceptable fit. This implies that a single temperature Maxwellian particle velocity distribution cannot produce the emission. Possible alternative explanations are explored, including multiple shocks along the line of sight, a pickup ion contribution, a non-thermal tail (Kappa distribution), emission from a precursor in a cosmic ray modified shock, or turbulence. An Hubble Space Telescope image shows a bright knot that might account for a low temperature contribution, and all the possibilities probably contribute at some level. We discuss the implications of each explanation for the shock parameters and physics of collisionless shocks, but cannot conclusively rule out any of them.

Raymond, John C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Winkler, P. Frank [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218 (United States); Lee, Jae-Joon; Park, Sangwook, E-mail: jraymond@cfa.harvard.ed, E-mail: winkler@middlebury.ed, E-mail: wpb@pha.jhu.ed, E-mail: lee.j.joon@gmail.co, E-mail: park@astro.psu.ed [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2010-04-01

133

Constraints on the Physics of Type Ia Supernovae from the X-Ray Spectrum of the Tycho Supernova Remnant  

Microsoft Academic Search

In this paper we use high-quality X-ray observations from XMM-Newton and Chandra to gain new insights into the explosion that originated Tycho's supernova 433 yr ago. We perform a detailed comparison between the ejecta emission from the spatially integrated X-ray spectrum of the supernova remnant and current models for Type Ia supernova explosions. We use a grid of synthetic X-ray

Carles Badenes; Kazimierz J. Borkowski; John P. Hughes; Una Hwang; Eduardo Bravo

2006-01-01

134

Electron-Ion Equilibration at Supernova Remnant Shock Fronts  

NASA Astrophysics Data System (ADS)

The degree of electron and proton heating at collisionless shocks is an open question in plasma physics. Any initial post-shock electron to proton temperature ratio from minimal heating of Te}/T{p = me}/m{p up to full equilibration of Te}/T{p = 1 is theoretically possible. Assuming either full or minimal equilibration when inferring the shock speed from a single temperature measurement leads to a large range of possible total shock energies. For my thesis I investigated this problem by examining the ratio of electron to proton temperatures in the outer blast wave of supernova remnant DEM L71 in the Large Magellanic Cloud. The proton temperatures were measured from broad H? widths observed using the Rutgers Fabry-Perot imaging spectrograph, while the electron temperatures were measured from Chandra X-ray data. With the use of new post-shock non-equilibrium ionization models for the electron temperature evolution we find evidence for an intermediate degree of temperature equilibration for shock speeds of 400-1000 km s-1. Our results are consistent with the trend found in other remnants by Ghavamian et al. (2001) of decreasing initial electron heating with increasing shock velocity. Further explorations of the degree of electron-proton equilibration will be presented as time permits. C.E. Rakowski has been supported by a NASA Graduate Student Researchers Program fellowship.

Rakowski, C. E.

2002-12-01

135

On the hadronic ?-ray emission from Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

Hadronic ?-ray emission from supernova remnants (SNRs) is an important tool to test shock acceleration of cosmic-ray protons. Tycho is one of nearly a dozen Galactic SNRs which are suggested to emit hadronic ?-ray emission. Among them, however, it is the only one in which the hadronic emission is proposed to arise from the interaction with a low-density (0.3 cm-3) ambient medium. Here we present an alternative hadronic explanation with a modest energy conversion efficiency (of the order of 1 per cent) for this young remnant. With such an efficiency, a normal electron-to-proton ratio (of the order of 10-2) is derived from the radio and X-ray synchrotron spectra, and an average ambient density that is at least one order of magnitude higher is derived from the hadronic ?-ray flux. This result is consistent with the multiband evidence of the presence of a dense medium from the north to the east of the Tycho SNR. The SNR-cloud association, in combination with the H i absorption data, helps to constrain the so-far controversial distance to Tycho and leads to an estimate of 2.5 kpc.

Zhang, Xiao; Chen, Yang; Li, Hui; Zhou, Xin

2013-02-01

136

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

137

Galactic cosmic ray origin sites: Supernova remnants and superbubbles  

NASA Astrophysics Data System (ADS)

We discuss processes in galactic cosmic ray (GCR) acceleration sites - supernova remnants, compact associations of young massive stars, and superbubbles. Mechanisms of efficient conversion of the mechanical power of the outflows driven by supernova shocks and fast stellar winds of young stars into magnetic fields and relativistic particles are discussed. The high efficiency of particle acceleration in the sources implies the importance of nonlinear feedback effects in a symbiotic relationship where the magnetic turbulence required to accelerate the CRs is created by the accelerated CRs themselves. Non-thermal emission produced by relativistic particles (both those confined in and those that escape from the cosmic accelerators) can be used to constrain the basic physical models of the GCR sources. High resolution X-ray synchrotron imaging, combined with GeV-TeV gamma ray spectra, is a powerful tool to probe the maximum energies of accelerated particles. Future MeV regime spectroscopy will provide unique information on the composition of accelerated particles.

Bykov, A. M.; Ellison, D. C.; Gladilin, P. E.; Osipov, S. M.

2012-12-01

138

VLBI observations of supernova remnants in Messier 82  

NASA Astrophysics Data System (ADS)

We have used the European VLBI Network (EVN) at 18cm to study five of the more compact radio sources in the starburst galaxy M82. The angular resolution of the observations is 15mas, corresponding to 0.2pc at the distance of M82. The observations reveal shells ranging in diameter from 40 to 90mas (0.6 to 1.4pc), although the strongest source (41.95+575) is only marginally resolved by these measurements (~20x10mas^2). We have found clear evidence for expansion in one of the shell sources (43.31+592) by re-analysing, in wide-field mode, EVN data taken in 1986. Between 1986 and 1997 this source has increased its diameter by 13.6+/-2mas, corresponding to an average expansion velocity of 9850+/-1500kms^-1. If we assume that the remnant is in free expansion, this is consistent with a supernova event in the early 1960s. Hence this remnant is almost certainly younger than the strongest, most compact source (41.95+575) which was known to be present in the 1960s. 41.95+575 shows no clear evidence for expansion (<4000kms^-1), consistent with a greater age; this is further evidence of its anomalous status. Comparison of the EVN images with earlier MERLIN data is also consistent with expansion in at least two more of the sources. We discuss the flux density variability of the compact sources in M82 and conclude that, with the exception of 41.95+575 and two transient sources, there is little evidence for significant changes in flux density of most of the remnants since the early 1980s.

Pedlar, A.; Muxlow, T. W. B.; Garrett, M. A.; Diamond, P.; Wills, K. A.; Wilkinson, P. N.; Alef, W.

1999-08-01

139

PHYSICAL STRUCTURE AND NATURE OF SUPERNOVA REMNANTS IN M101  

SciTech Connect

Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H{alpha} and [S II] images. We have used archival Hubble Space Telescope (HST) H{alpha} and broadband images as well as stellar photometry of 55 SNR candidates to examine their physical structure, interstellar environment, and underlying stellar population. We have also obtained high-dispersion echelle spectra to search for shocked high-velocity gas in 18 SNR candidates, and identified X-ray counterparts to SNR candidates using data from archival observations made by the Chandra X-Ray Observatory. Twenty-one of these 55 SNR candidates studied have X-ray counterparts, although one of them is a known ultraluminous X-ray source. The multi-wavelength information has been used to assess the nature of each SNR candidate. We find that within this limited sample, {approx}16% are likely remnants of Type Ia SNe and {approx}45% are remnants of core-collapse SNe. In addition, about {approx}36% are large candidates which we suggest are either superbubbles or OB/H II complexes. Existing radio observations are not sensitive enough to detect the non-thermal emission from these SNR candidates. Several radio sources are coincident with X-ray sources, but they are associated with either giant H II regions in M101 or background galaxies. The archival HST H{alpha} images do not cover the entire galaxy and thus prevents a complete study of M101. Furthermore, the lack of HST [S II] images precludes searches for small SNR candidates which could not be identified by ground-based observations. Such high-resolution images are needed in order to obtain a complete census of SNRs in M101 for a comprehensive investigation of the distribution, population, and rates of SNe in this galaxy.

Franchetti, Nicholas A.; Gruendl, Robert A.; Chu, You-Hua; Dunne, Bryan C. [Astronomy Department, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Pannuti, Thomas G.; Grimes, Caleb K. [Department of Earth and Space Sciences, Space Science Center, Morehead State University, 235 Martindale Drive, Morehead, KY 40351 (United States); Kuntz, Kip D. [Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Chen, C.-H. Rosie [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Aldridge, Tabitha M., E-mail: franche1@illinois.edu, E-mail: gruendl@astro.illinois.edu, E-mail: yhchu@astro.illinois.edu, E-mail: bdunne@astro.illinois.edu, E-mail: t.pannuti@moreheadstate.edu, E-mail: ckgrim01@moreheadstate.edu, E-mail: kuntz@pha.jhu.edu, E-mail: rchen@mpifr-bonn.mpg.de, E-mail: z1611057@students.niu.edu [Department of Geology and Environmental Geosciences, Northern Illinois University, Davis Hall 312, Normal Road, DeKalb, IL 60115 (United States)

2012-04-15

140

THE MIPSGAL VIEW OF SUPERNOVA REMNANTS IN THE GALACTIC PLANE  

SciTech Connect

We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 {mu}m), in the coordinate ranges 10{sup 0} < l < 65{sup 0} and 285{sup 0} < l < 350{sup 0}, |b| < 1{sup 0}, using MIPS aboard the Spitzer Space Telescope. We search for infrared counterparts to SNRs in Green's catalog and identify 39 out of 121, i.e., a detection rate of about 32%. Such a relatively low detection fraction is mainly due to confusion with nearby foreground/background sources and diffuse emission. The SNRs in our sample show a linear trend in [F{sub 8}/F{sub 24}] versus [F{sub 70}/F{sub 24}]. We compare their infrared fluxes with their corresponding radio flux at 1.4 GHz and find that most remnants have a ratio of 70 {mu}m to 1.4 GHz which is similar to those found in previous studies of SNRs (with the exception of a few that have ratios closer to those of H II regions). Furthermore, we retrieve a slope close to unity when correlating infrared (24 and 70 {mu}m) with 1.4 GHz emission. Our survey is more successful in detecting remnants with bright X-ray emission, which we find is well correlated with the 24 {mu}m morphology. Moreover, by comparing the power emitted in the X-ray, infrared, and radio, we conclude that the energy released in the infrared is comparable to the cooling in the X-ray range.

Pinheiro Goncalves, D. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Noriega-Crespo, A.; Paladini, R.; Carey, S. J. [Spitzer Science Center, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Martin, P. G., E-mail: goncalves@astro.utoronto.ca [CITA, University of Toronto, 60 St. George Street, Toronto, ON, M5S 3H4 (Canada)

2011-08-15

141

Physical Structure and Nature of Supernova Remnants in M101  

NASA Astrophysics Data System (ADS)

Supernova remnant (SNR) candidates in the giant spiral galaxy M101 have been previously identified from ground-based H? and [S II] images. We have used archival Hubble Space Telescope (HST) H? and broadband images as well as stellar photometry of 55 SNR candidates to examine their physical structure, interstellar environment, and underlying stellar population. We have also obtained high-dispersion echelle spectra to search for shocked high-velocity gas in 18 SNR candidates, and identified X-ray counterparts to SNR candidates using data from archival observations made by the Chandra X-Ray Observatory. Twenty-one of these 55 SNR candidates studied have X-ray counterparts, although one of them is a known ultraluminous X-ray source. The multi-wavelength information has been used to assess the nature of each SNR candidate. We find that within this limited sample, ~16% are likely remnants of Type Ia SNe and ~45% are remnants of core-collapse SNe. In addition, about ~36% are large candidates which we suggest are either superbubbles or OB/H II complexes. Existing radio observations are not sensitive enough to detect the non-thermal emission from these SNR candidates. Several radio sources are coincident with X-ray sources, but they are associated with either giant H II regions in M101 or background galaxies. The archival HST H? images do not cover the entire galaxy and thus prevents a complete study of M101. Furthermore, the lack of HST [S II] images precludes searches for small SNR candidates which could not be identified by ground-based observations. Such high-resolution images are needed in order to obtain a complete census of SNRs in M101 for a comprehensive investigation of the distribution, population, and rates of SNe in this galaxy.

Franchetti, Nicholas A.; Gruendl, Robert A.; Chu, You-Hua; Dunne, Bryan C.; Pannuti, Thomas G.; Kuntz, Kip D.; Chen, C.-H. Rosie; Grimes, Caleb K.; Aldridge, Tabitha M.

2012-04-01

142

Acceleration of cosmic rays and gamma-ray emission from supernova remnants in the Galaxy  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are believed to be accelerated at supernova remnant shocks. Though very popular and robust, this conjecture still needs a conclusive proof. The strongest support to this idea is probably the fact that supernova remnants are observed in gamma-rays, which are indeed expected as the result of the hadronic interactions between the cosmic rays accelerated at the shock and the ambient gas. However, also leptonic processes can, in most cases, explain the observed gamma-ray emission. This implies that the detections in gamma-rays do not necessarily mean that supernova remnants accelerate cosmic ray protons. To overcome this degeneracy, the multiwavelength emission (from radio to gamma-rays) from individual supernova remnants has been studied and in a few cases it has been possible to ascribe the gamma-ray emission to one of the two processes (hadronic or leptonic). Here, we adopt a different approach and, instead of a case-by-case study we aim for a population study and we compute the number of supernova remnants which are expected to be seen in TeV gamma-rays above a given flux under the assumption that these objects indeed are the sources of cosmic rays. The predictions found here match well with current observational results, thus providing a novel consistency check for the supernova remnant paradigm for the origin of Galactic cosmic rays. Moreover, hints are presented for the fact that particle spectra significantly steeper than E-2 are produced at supernova remnants. Finally, we expect that several of the supernova remnants detected by HESS in the survey of the Galactic plane should exhibit a gamma-ray emission dominated by hadronic processes (i.e. neutral-pion decay). The fraction of the detected remnants for which the leptonic emission dominates over the hadronic one depends on the assumed values of the physical parameters (especially the magnetic field strength at the shock) and can be as high as roughly a half.

Cristofari, P.; Gabici, S.; Casanova, S.; Terrier, R.; Parizot, E.

2013-10-01

143

Supernova Remnants in the Magellanic Clouds. II. Supernova Remnant Breakouts from N11L and N86  

NASA Astrophysics Data System (ADS)

The evolution of a supernova remnant (SNR) is heavily influenced by the interstellar conditions surrounding the remnant. This is particularly true in cases where the SNR is breaking out into a low-density area in the surrounding medium. We examine two promising candidates for the study of SNR breakouts in the Large Magellanic Cloud (LMC): N11L and N86. The remnant N11L has a filamentary extension that interrupts the shell; to the north of this extension, we find a region of diffuse radio and X-ray emission that shows only faint filaments in optical images. The discontinuous distribution of velocities in the shell material and the apparent flattening of the radio spectral index in the outflow region suggest substantial turbulence in the outflowing material and clumpiness in the surrounding interstellar medium (ISM). N86, on the other hand, shows a large breakout to the north, as well as several smaller possible outflows around the shell. We find that the northern breakout has a well-defined spherical expansion pattern, faint diffuse X-ray emission, and a highly filamentary optical structure. Our velocity data indicate that material breaking out to the north is expanding at a maximum of 100 km s^-1. The consequences of these breakouts on the parent remnants are discussed: N11L appears to have a lower thermal energy, by an order of magnitude, than other LMC remnants used for comparison. N86, on the other hand, shows a thermal energy fairly similar to the comparison SNRs, perhaps due to a more gradual loss of hot gas. The implications of the breakout structures for the surrounding medium are also discussed. The breakout in N11L coincides with a possible low-density cavity, which is enclosed in a shell structure on the western edge of the N11 H II complex. The less dense shell of N86 and the more distributed pattern of the breakouts suggest a relatively low density ISM with substantial local density variations.

Williams, Rosa Murphy; Chu, You-Hua; Dickel, John R.; Smith, R. Chris; Milne, Douglas K.; Winkler, P. Frank

1999-04-01

144

Anomalous Radio Quiet Zones in X-ray Bright Young Supernova Remnants G54.1+0.3 and 3C58  

NASA Astrophysics Data System (ADS)

We present analyses of the young, Crab-like supernova remnants (SNRs) G54.1+0.3 and 3C58 in the X-ray and radio wavelength regions using public data from the Chandra X-Ray Observatory and the Very Large Array. By overlaying the X-ray and radio images, we discover similar anomalous radio quiet point sources in each object that are slightly offset from the X-ray pulsar ( 5'' and 10' for G54.1+0.3 and 3C58 respectively). The radio quiet sources are likely not coincident with the X-ray pulsars due to the unrealistically large kick velocities that the pulsars would have to possess. To explain this radio offset, we discuss simple physical models, several of which appear promising, but all of which have significant weaknesses.

Chen, J. Z.; Massenburg, S. J.; Wolpert, G. A.; Keohane, J. W.; Olbert, C. M.; Clearfield, C. R.

2002-12-01

145

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

146

AKARI INFRARED OBSERVATIONS OF THE SUPERNOVA REMNANT G292.0+1.8: UNVEILING CIRCUMSTELLAR MEDIUM AND SUPERNOVA EJECTA  

SciTech Connect

We present the results of AKARI observations of the O-rich supernova remnant (SNR) G292.0+1.8 using six Infrared Camera (IRC) and four Far-Infrared Surveyor bands covering 2.7-26.5 mum and 50-180 mum, respectively. The AKARI images show two prominent structures; a bright equatorial ring (ER) structure along the east-west direction and an outer elliptical shell structure surrounding the remnant. The ER structure is clumpy and incomplete with its western end opened. The outer shell is almost complete and slightly squeezed along the north-south direction. The central position of the outer shell is approx1' northwest from the embedded pulsar and coincides with the center of the ER structure. In the northern and southwestern regions, there is also faint emission with a sharp boundary beyond the bright shell structure. The ER and the elliptical shell structures were partly visible in optical and/or X-rays, but they are much more clearly revealed in our AKARI images. There is no evident difference in infrared colors of the two prominent structures, which is consistent with the previous proposition that both structures are of circumstellar origin. However, we have detected faint infrared emission of a considerably high 15/24 mum ratio associated with the supernova (SN) ejecta in the southeastern and northwestern areas. Our IRC spectra show that the high ratio is at least partly due to the emission lines from Ne ions in the SN ejecta material. In addition, we detect a narrow, elongated feature outside the SNR shell. We derive the physical parameters of the infrared-emitting dust grains in the shocked circumstellar medium (CSM) and compare the result with model calculations of dust destruction by an SN shock. The AKARI results suggest that the progenitor was at the center of the infrared circumstellar shell in the red supergiant stage and that the observed asymmetry in the SN ejecta could be a result of either a dense CSM in the equatorial plane and/or an asymmetric explosion.

Lee, Ho-Gyu; Sakon, Itsuki; Onaka, Takashi [Department of Astronomy, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Koo, Bon-Chul [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Moon, Dae-Sik [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Jeong, Woong-Seob [Korea Astronomy and Space Science Institute, 61-1, Whaam-dong, Yuseong-gu, Deajeon 305-348 (Korea, Republic of); Kaneda, Hidehiro [Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Nozawa, Takaya [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8568 (Japan); Kozasa, Takashi, E-mail: hglee@astron.s.u-tokyo.ac.j, E-mail: isakon@astron.s.u-tokyo.ac.j, E-mail: onaka@astron.s.u-tokyo.ac.j, E-mail: koo@astrohi.snu.ac.k, E-mail: moon@astro.utoronto.c, E-mail: jeongws@kasi.re.k, E-mail: kaneda@u.phys.nagoya-u.ac.j, E-mail: tnozawa@mail.sci.hokudai.ac.j, E-mail: kozasa@mail.sci.hokudai.ac.j [Department of Cosmosciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan)

2009-11-20

147

Simulations of mixed-morphology supernova remnants with anisotropic thermal conduction  

Microsoft Academic Search

We explore the role of anisotropic thermal conduction on the evolution of supernova remnants (SNRs) through interstellar media with a range of densities via numerical simulations. We find that a remnant expanding in a dense environment can produce centre-bright hard X-ray emission within 20 kyr, and centre-bright soft X-ray emission within 60 kyr of the supernova event. In a more

David A. Tilley; Dinshaw S. Balsara; J. Christopher Howk

2006-01-01

148

Numerical Code for Fitting Radial Emission Profile of a Shell Supernova Remnant  

NASA Astrophysics Data System (ADS)

Expressions for surface brightness distribution and for flux density have been theoretically derived in the case of two simple models of a shell supernova remnant. The models are: a homogenous optically thin emitting shell with constant emissivity and a synchrotron shell source with radial magnetic field. Interactive Data Language (IDL) codes for fitting theoretically derived emission profiles assuming these two models to mean profiles of shell supernova remnants obtained from radio observations have been written.

Arbutina, B.; Opsenica, S.

2012-12-01

149

Fermi-LAT Observation of Supernova Remnant S147  

SciTech Connect

We present an analysis of gamma-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region around SNR S147 (G180.0-1.7). A spatially extended gamma-ray source detected in an energy range of 0.2-10 GeV is found to coincide with SNR S147. We confirm its spatial extension at >5{sigma} confidence level. The gamma-ray flux is (3.8 {+-} 0.6) x 10{sup -8} photons cm{sup -2} s{sup -1}, corresponding to a luminosity of 1.3 x 10{sup 34} (d/1.3 kpc){sup 2} erg s{sup -1} in this energy range. The gamma-ray emission exhibits a possible spatial correlation with prominent H{alpha} filaments of S147. There is no indication that the gamma-ray emission comes from the associated pulsar PSR J0538+2817. The gamma-ray spectrum integrated over the remnant is likely dominated by the decay of neutral {pi} mesons produced through the proton-proton collisions in the filaments. Reacceleration of pre-existing CRs and subsequent adiabatic compression in the filaments is sufficient to provide the required energy density of high-energy protons.

Katsuta, J.; Uchiyama, Y.; Tanaka, T.; /SLAC /KIPAC, Menlo Park; Tajima, H.; /SLAC /KIPAC, Menlo Park /Nagoya U., Solar-Terrestrial Environ. Lab.; Bechtol, K.; Funk, S.; Lande, J.; /SLAC /KIPAC, Menlo Park; Ballet, J.; /AIM, Saclay; Hanabata, Y.; /Hiroshima U.; Lemoine-Goumard, M.; /CENBG, Gradignan; Takahashi, T.; /JAXA, Sagamihara

2012-08-17

150

Quasi-regular staying of solar system in supernova remnants and natural earth history  

Microsoft Academic Search

The Solar system, oscillating relative the Galaxy midplane during its revolution around the Galactic center, can occasionally fall inside the gas-dust interstellar clouds, which include remnants of Supernova explosions. These are mainly accumulated in the vicinity of the Galactic midplane. Being the main sources of the cosmic rays, such remnants are characterized by a high density of relativistic particles. We

Vsevolod M. Byakov; Sergey V. Stepanov; Ol'ga P. Stepanova

1997-01-01

151

Interpretation of the number versus diameter distribution for supernova remnants in the Large Magellanic Cloud  

Microsoft Academic Search

An examination is conducted of the cumulative number versus diameter relation for an X-ray selected sample of supernova remnants in the Large Magellanic Cloud in an attempt to understand the evolutionary state of these objects. Previous studies have suggested that the observed linear N(D) relation requires the remnants in the cloud to be freely expanding. Detailed calculations have been carried

J. P. Hughes; D. J. Helfand; S. M. Kahn

1984-01-01

152

An Optical Search for Supernova Remnants in Nearby Spiral Galaxies  

NASA Astrophysics Data System (ADS)

We have conducted an optical search for supernova remnants (SNRs) in six nearby spiral galaxies. Observations were made on the 1.3 m McGraw-Hill and 2.4 m Hiltner telescopes at the Michigan-Dartmouth-MIT Observatory and on the 4 m Mayall telescope at Kitt Peak National Observatory. Our technique consisted of imaging galaxies with narrow H? and (S II) ?lambda6716,6731 filters, identifying (S II) -bright emission nebulae, and using spectra of a few of these nebulae in each galaxy to calibrate the (S II) /H? ratios obtained from the images. Any emission nebula with (S II) /H?geq0.45 was identified as a SNR. We identified 204 SNRs in our six target galaxies: 3 in NGC 5204, 5 in NGC 5585, 27 in NGC 6946, 35 in NGC 2403, 41 in M81, and 93 in M101. This survey has doubled the number of galaxies that have been well searched for SNRs, and increased the number of known extragalactic SNRs by about 50%. No SNRs were detected inside H II regions, and our total sample appears biased against detecting large, faint SNRs. Statistical analysis of the spatial distribution of detected SNRs showed that those in NGC 2403, M81, and M101 are associated with star-forming regions, and therefore a significant fraction of these remnants are the result of Type II or Ib/c supernovae. Thirty-one objects in our survey have estimated diameters ?100 pc, which is larger than physically possible for a single SNR in an ISM of typical density, and therefore probably represent an individual SNR in a low-density medium, a stellar-wind-shocked nebula/SNR combination, and? a multiple SNR. We combined our SNR samples with published results of optical SNR searches in the Large Magellanic Cloud, Small Magellanic Cloud, M31, M33, NGC 300, and NGC 7793 to create an ensemble of 12 SNR samples. Among several physical trends found in this ensemble was a constant value of Dmode?40 pc, suggesting a significant fraction of the detected SNRs are in a similar evolutionary stage.

Matonick, David Michael

153

Supernova remnant evolution in uniform and non-uniform media  

NASA Astrophysics Data System (ADS)

Aims:In this work numerical simulations showing the time evolution of supernova remnants (SNRs) in uniform and non-uniform interstellar medium (ISM) are presented. Methods: We use a hydrodynamic model including a kinematic calculation of the interstellar magnetic field. Important parameters influencing SNR evolution include the ejecta mass and energy of the remnant, as well as the ISM density and adiabatic index. Results: By varying these parameters we constructed an analytical expression giving the return time of the SNR reverse shock to the origin, in terms of these parameters. We also found that the reverse shock spends half of its time moving outward and the other half returning to the origin. Also computed is SNR evolution in non-uniform media where the blast wave moves from one medium into either a less or more dense medium. As the SNR moves into a medium of higher density a reflection wave is created at the interface between the two media which is driven back toward the center. This drives mass via a nonspherical flow away from the discontinuity. As this wave moves inward it also drags some of the ISM field lines (if the field is parallel with the interface) with it and heats the inside of the SNR resulting in larger temperatures in this region. When a SNR explodes in a medium with a high density and the blast wave propagates into a medium with a lower density, a cavity is being blown away changing the geometry of the high density region. Also, once the forward shock moves into the medium of less density a second reverse shock will start to evolve in this region.

Ferreira, S. E. S.; de Jager, O. C.

2008-01-01

154

A Deep Chandra Observation of Kepler's Supernova Remnant: A Type Ia Event with Circumstellar Interaction  

Microsoft Academic Search

We present initial results of a 750 ks Chandra observation of the remnant of Kepler's supernova of AD 1604. The strength and prominence of iron emission, together with the absence of O-rich ejecta, demonstrate that Kepler resulted from a thermonuclear supernova, even though evidence for circumstellar interaction is also strong. We have analyzed spectra of over 100 small regions, and

Stephen P. Reynolds; Kazimierz J. Borkowski; Una Hwang; John P. Hughes; Carles Badenes; J. M. Laming; J. M. Blondin

2007-01-01

155

X-Ray Emission from Dust Grains in Young Supernova Remnants  

Microsoft Academic Search

Refractory elements in the interstellar medium are almost always heavily depleted from gas onto dust grains. They remain locked in dust grains for a long time after the passage of a supernova blast wave, as demonstrated by observations of infrared emission from supernova remnants (SNRs). Dust grains contain elements such as Mg, Si, Ca, and Fe which, while in gaseous

K. J. Borkowski; A. E. Szymkowiak

1996-01-01

156

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

Microsoft Academic Search

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 discernible X-ray shell. In addition, X-ray-bright knots dot W44's image. The spectral analysis of the Chandra data shows that the remnant's hot bright

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

2004-01-01

157

Optical pulsar in the Large Magellanic Cloud remnant 0540-69. 3  

SciTech Connect

We have detected pulsed optical emission from the Large Magellanic Cloud (LMC) X-ray pulsar PSR 0540-693 (Seward et al. 1984). The pulsed emission has a time averaged magnitude of approximately 22.7. The X-ray pulsar was discovered in the LMC remnant, 0540-69.3 as a pulse repetition period of approx. 50 milliseconds (ms) in Einstein Obsrvatory data (Seward et al. 1984). Earlier, Clark et al. (1982) had noted that this remnant resembles the Crab Nebula because of the X-ray power law spectrum, and suggested that the nebular emission was synchrotron radiation powered by a central pulsar. After the announcement of X-ray pulsed emission, Chanan et al. (1984) measured the broad optical band properties of the nebula and found evidence for synchrotron emission. They reported that the 4.5 arc second continuum emission remnant has only a tenth the luminosity of the Crab Nebula. We have recorded broad-band optical time-series data at 1 ms intervals with the 4-m and 1.5-m Cerro Tololo telescopes and have found strong pulsations, employing the usual Fourier transform methods. A summary of the observations, including magnitudes, barycentric frequencies and times of arrival is given.

Middleditch, J.; Pennypacker, C.R.

1984-01-01

158

EFFECTS OF NEUTRAL PARTICLES ON MODIFIED SHOCKS AT SUPERNOVA REMNANTS  

SciTech Connect

H{alpha} emission from supernova remnants (SNRs) implies the existence of neutral hydrogens in the ambient medium. In the precursor of an SNR shock modified by cosmic rays (CRs), upstream plasmas are pushed by the CR pressure, but neutral particles are not, so that the relative velocity appears and some neutral particles become pickup ions by the charge exchange process in the precursor. We investigate how the pickup ions generated in the precursor affect the shock structure and the particle acceleration. If the CR pressure is larger than 20% of the shock ram pressure, the compression of the subshock becomes smaller than that without pickup ions because of the pressure of the pickup ions. Moreover, even if the shock is modified by CRs, the total compression ratio can be smaller than 4. In addition, the pickup ions play an important role for the injection into the particle acceleration. If the shock is a quasi-perpendicular shock and if the multiply reflected ion acceleration occurs, the CR spectrum can be harder than that of the test particle diffusive shock acceleration below GeV.

Ohira, Yutaka [Theory Center, Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801 (Japan); Takahara, Fumio, E-mail: ohira@post.kek.j [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043 (Japan)

2010-09-20

159

A NEW EVOLUTIONARY PHASE OF SUPERNOVA REMNANT 1987A  

SciTech Connect

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 {approx}1.5 yr (since day {approx}8000), the soft X-ray flux has significantly flattened, staying (within uncertainties) at f{sub X} {approx} 5.7 x 10{sup -12} erg cm{sup -2} s{sup -1} (corresponding to L{sub X} {approx} 3.6 x 10{sup 36} erg s{sup -1}) in the 0.5-2 keV band. This remarkable change in the recent soft X-ray light curve suggests that the forward shock is now interacting with a decreasing density structure, after interacting with an increasing density gradient over {approx}10 yr prior to day {approx}8000. Possibilities may include the case that the shock is now propagating beyond a density peak of the inner ring. We briefly discuss some possible implications on the nature of the progenitor and the future prospects of our Chandra monitoring observations.

Park, Sangwook [Department of Physics, University of Texas at Arlington, 108 Science Hall, Box 19059, Arlington, TX 76019 (United States); Zhekov, Svetozar A. [Space and Solar-Terrestrial Research Institute, Moskovska str. 6, Sofia 1000 (Bulgaria); Burrows, David N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Racusin, Judith L. [NASA/Goddard Space Flight Center, 8800 Greenbelt Road, Code 661, Greenbelt, MD 20771 (United States); Dewey, Daniel [MIT Kavli Institute, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); McCray, Richard, E-mail: s.park@uta.edu [JILA, University of Colorado, Box 440, Boulder, CO 80309 (United States)

2011-06-01

160

Self consistent particle acceleration in 2D supernova remnant shocks  

NASA Astrophysics Data System (ADS)

We present numerical solutions of a two dimensional, self consistent model of cosmic ray modified, supernova remnant shocks developed by Zakharian (2000). The equations of the model consist of the Parker transport equation for the energetic particle momentum distribution function, f, including convection, anisotropic diffusion, drifts, and adiabatic energy changes. The transport equation is coupled self consistently, with the equations of ideal magnetohydrodynamics (MHD) describing the thermal plasma, but suitably modified to take into account injection at the shock, and with an extra force - pc, exerted by the cosmic ray pressure pc in the momentum equation for the system. The model incorporates anisotropic diffusion of the cosmic rays, including diffusion parallel (? ), and perpendicular (??) to the mean magnetic field, and the role of particle drifts due to the anti-symmetric diffusion coefficient ?A. For the case of an initially uniform background magnetic field, the anisotropic diffusion of the cosmic rays leads to an anisotropic spatial distribution of thermal plasma, cosmic rays and magnetic field. The shock is quasi-parallel over the poles (? = 0 ), and quasi-perpendicular near the equator (? = 90 ), where ? = 0 corresponds to the initial magnetic field direction. The evolution of the SNR shock, and the momentum distribution f(r, p, t) of the energetic particles are investigated. The dependence of the solutions and acceleration rate at the shock on the parameter ? = ??/? and the shock obliquity ? are studied in detail.

Zakharian, A. R.; Webb, G. M.; Brio, M.; Jokipii, J. R.

2001-08-01

161

Supernova Remnant Kes 17: An Efficient Cosmic Ray Accelerator inside a Molecular Cloud  

NASA Astrophysics Data System (ADS)

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.; Castro, Daniel; Slane, Patrick O.; Temim, Tea; Hughes, John P.; Rakowski, Cara

2013-11-01

162

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

163

Escape of cosmic-ray electrons from supernova remnants  

NASA Astrophysics Data System (ADS)

We investigate the escape of cosmic ray (CR) electrons from a supernova remnant (SNR) to interstellar space. We show that CR electrons escape in order, from high energies to low energies, like CR nuclei. However, the escape starts later than the beginning of the Sedov phase at an SNR age of 103 to 7 103 yr, and the maximum energy of runaway CR electrons is below the knee at about 0.3-50 TeV because, unlike CR nuclei, CR electrons lose their energy as a result of synchrotron radiation. The highest-energy CR electrons might have already been detected by the High Energy Stereoscopic System (HESS) and MAGIC as a cut-off in the CR electron spectrum, and it will be probed by the Alpha Magnetic Spectrometer (AMS-02), the Calorimeteric Electron Telescope (CALET), the Cherenkov Telescope Array (CTA) and the Large High Altitude Air Shower Observatory (LHAASO) experiments. We also calculate the spatial distribution of runaway CR electrons and their radiation spectra around SNRs. Contrary to common belief, maximum-energy photons of synchrotron radiation around 1 keV are emitted by runaway CR electrons, which have been caught up by the shock. Inverse Compton scattering by runaway CR electrons can dominate the gamma-ray emission from runaway CR nuclei via pion decay. Both are detectable by CTA and LHAASO and they can give clues to the origin of CRs and the amplification of magnetic fluctuations around the SNR. We also discuss middle-aged and/or old SNRs as unidentified very-high-energy gamma-ray sources.

Ohira, Yutaka; Yamazaki, Ryo; Kawanaka, Norita; Ioka, Kunihito

2012-11-01

164

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

165

Einstein IPC imaging and spectral observations of the supernova remnant HB 9  

SciTech Connect

In radio wavelengths, HB 9 is a large supernova remnant. The central area of HB 9 has been observed with fairly complete coverage by four Einstein IPC fields. A soft X-ray image and results from analysis of X-ray spectra from the IPC observations are presented. HB 9 has spatial variations in X-ray temperature from 0.4 to 1.2 keV, with the temperature decreasing from center to edge. For a distance of 1.1 kpc, the 0.2-4 keV luminosity is 5 x 10 to the 34th ergs/s. A Sedov supernova remnant model does not fit HB 9's properties. Supernova remnant models for expansion into a three-component ISM give a satisfactory fit and yield an age of 14,000 yr. 19 references.

Leahy, D.A.

1987-11-01

166

Multifrequency study of SNR J0533-7202, a new supernova remnant in the LMC  

NASA Astrophysics Data System (ADS)

We present a detailed study of Australia Telescope Compact Array observations of a newly discovered Large Magellanic Cloud supernova remnant (SNR), SNR J0533-7202. This object follows a horseshoe morphology, with a size of 37 pc 28 pc (1 pc uncertainty in each direction). It exhibits a radio spectrum with the intrinsic synchrotron spectral index of ? = -0.47 0.06 between 73 and 6 cm. We report detections of regions showing moderately high fractional polarization at 6 cm, with a peak value of 36 6 per cent and a mean fractional polarization of 12 7 per cent. We also estimate an average rotation measure across the remnant of -591 rad m-2. The current lack of deep X-ray observation precludes any conclusion about high-energy emission from the remnant. The association with an old stellar population favours a thermonuclear supernova origin of the remnant.

Bozzetto, L. M.; Filipovi?, M. D.; Crawford, E. J.; Sasaki, M.; Maggi, P.; Haberl, F.; Uroevi?, D.; Payne, J. L.; De Horta, A. Y.; Stupar, M.; Gruendl, R.; Dickel, J.

2013-07-01

167

Exploring the X-ray Morphology of the Supernova Remnant Kes 27 using Numerical Simulations  

NASA Astrophysics Data System (ADS)

Kesteven 27 is a member of the class of thermal composite or mixed-morphology remnants, which can show thermal X-ray emission extending all the way in towards the center. The Chandra image shows two incomplete shell-like features in the north-eastern half, with brightness fading towards the southwest. The X-ray and radio structure led Chen et al. (2008) to suggest that the morphology represents a supernova remnant expanding in a windblown bubble. The two X-ray rings represent the outer shock of the supernova remnant, and a reflected shock arising from collision with a dense shell. Using numerical simulations followed by a computation of the X-ray emission, we explore this possibility. Our initial modeling suggests that the scenario discussed by Chen et al. (2008) may not work. We suggest and discuss modifications to this scenario that may be able to reproduce the observed morphology, and the implications for thermal composite remnants.

Dwarkadas, Vikram; Dewey, D.

2013-04-01

168

Simulating anisotropic thermal conduction in supernova remnants - II. Implications for the interstellar medium  

Microsoft Academic Search

We present a large number of 2.5D simulations of supernova remnants expanding into interstellar media having a range of densities, temperatures and magnetic field strengths. The simulations include equilibrium cooling and anisotropic, flux-limited thermal conduction along magnetic field lines. The volume of hot gas produced during the remnant's evolution is shown to be strongly influenced by the inclusion of thermal

Dinshaw S. Balsara; Anthony J. Bendinelli; David A. Tilley; Andrew R. Massari; J. Christopher Howk

2008-01-01

169

Maximum Energies of Shock?accelerated Electrons in Young Shell Supernova Remnants  

Microsoft Academic Search

Young supernova remnants (SNRs) are often assumed to be the source of cosmic rays up to energies approaching the slight steepening in the cosmic-ray spectrum at around 1000 TeV, known as the knee.?? We show that the observed X-ray emission of 14 radio-bright shell remnants, including all ve historical shells, can be used to put limits on the energy

Stephen P. Reynolds; Jonathan W. Keohane

1999-01-01

170

The plerionic supernova remnant G21.5-0.9: In and out  

NASA Astrophysics Data System (ADS)

The absence of a supernova remnant (SNR) shell surrounding the Crab and other plerions (pulsar wind nebulae) has been a mystery for three decades. G21.5-0.9 is a particularly intriguing plerionic SNR in which the central powering engine is not yet detected. Early CHANDRA observations revealed a faint extended X-ray halo which was suggested to be associated with the SNR shell; however its spectrum was non-thermal, unlike what is expected from an SNR shell. On the other hand, a plerionic origin to the halo is problematic since the X-ray plerion would be larger than the radio plerion. We present here our analysis of an integrated 245 ks of archival CHANDRA data acquired with the High-Resolution Camera (HRC) and 520 ks acquired with the Advanced CCD Imaging Spectrometer (ACIS). This study provides the deepest and highest resolution images obtained to date. The resulting images reveal for the first time: (1) a limb-brightened morphology in the eastern section of the halo, and (2) a rich structure in the inner (40?-radius) bright plerion including wisps and a double-lobed morphology with an axis of symmetry running in the northwest-southeast direction. Our spatially resolved spectroscopic study of the ACIS-I data indicates that the photon index steepens with increasing distance from the central point source out to a radius of 40? then becomes constant at 2.4 in the X-ray halo (for a column density NH = 2.2 10 22 cm -2). No line emission was found from the eastern limb; however marginal evidence for line emission in the halo's northern knots was found. This study illustrates the need for deep CHANDRA observations to reveal the missing SNR material in Crab-like plerions.

Matheson, Heather; Safi-Harb, Samar

171

Multi-frequency study of supernova remnants in the Large Magellanic Cloud. Confirmation of the supernova remnant status of DEM L205  

NASA Astrophysics Data System (ADS)

Context. The Large Magellanic Cloud (LMC) is an ideal target for the study of an unbiased and complete sample of supernova remnants (SNRs). We started an X-ray survey of the LMC with XMM-Newton, which, in combination with observations at other wavelengths, will allow us to discover and study remnants that are either even fainter or more evolved (or both) than previously known. Aims: We present new X-ray and radio data of the LMC SNR candidate DEM L205, obtained by XMM-Newton and ATCA, along with archival optical and infrared observations. Methods: We use data at various wavelengths to study this object and its complex neighbourhood, in particular in the context of the star formation activity, past and present, around the source. We analyse the X-ray spectrum to derive some remnant's properties, such as age and explosion energy. Results: Supernova remnant features are detected at all observed wavelengths : soft and extended X-ray emission is observed, arising from a thermal plasma with a temperature kT between 0.2 keV and 0.3 keV. Optical line emission is characterised by an enhanced [S ii]-to-H? ratio and a shell-like morphology, correlating with the X-ray emission. The source is not or only tentatively detected at near-infrared wavelengths (shorter than 10 ?m), but there is a detection of arc-like emission at mid and far-infrared wavelengths (24 and 70 ?m) that can be unambiguously associated with the remnant. We suggest that thermal emission from dust heated by stellar radiation and shock waves is the main contributor to the infrared emission. Finally, an extended and faint non-thermal radio emission correlates with the remnant at other wavelengths and we find a radio spectral index between -0.7 and -0.9, within the range for SNRs. The size of the remnant is ~79 64 pc and we estimate a dynamical age of about 35 000 years. Conclusions: We definitely confirm DEM L205 as a new SNR. This object ranks amongst the largest remnants known in the LMC. The numerous massive stars and the recent outburst in star formation around the source strongly suggest that a core-collapse supernova is the progenitor of this remnant. 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.; Bozzetto, L. M.; Filipovi?, M. D.; Points, S. D.; Chu, Y.-H.; Sasaki, M.; Pietsch, W.; Gruendl, R. A.; Dickel, J.; Smith, R. C.; Sturm, R.; Crawford, E. J.; De Horta, A. Y.

2012-10-01

172

FAR-INFRARED LUMINOUS SUPERNOVA REMNANT Kes 17  

SciTech Connect

We present the results of infrared (IR; 2.5-160 {mu}m) observations of the supernova remnant (SNR) Kes 17 based on the data obtained with the AKARI and Spitzer satellites. We first detect bright continuum emission of its western shell in the mid- and far-IR wavebands together with its near-IR molecular line emission. We also detect hidden mid-IR emission of its southern shell after subtraction of the background emission in this region. The far-IR luminosity of the western shell is {approx}8100 L{sub sun}, which makes Kes 17 one of the few SNRs of significant far-IR emission. The fittings of the spectral energy distribution indicate the existence of two dust components: {approx}79 K (hot) and {approx}27 K (cold) corresponding to the dust masses of {approx}6.2 x 10{sup -4} M{sub sun} and {approx}6.7 M{sub sun}, respectively. We suggest that the hot component represents the dust emission of the material swept up by the SNR to its western and southern boundaries, compatible with the distribution of radio continuum emission overlapping the mid-IR emission in the western and southern shells. The existence of hot ({approx}2000 K), shocked dense molecular gas revealed by the near-IR molecular line emission in the western shell, on the other hand, suggests that the cold dust component represents the dust emission related to the interaction between the SNR and nearby molecular gas. The excitation conditions of the molecular gas appear to be consistent with those from shocked, clumpy admixture gas of different temperatures. We discuss three possibilities for the origin of the bright far-IR emission of the cold dust in the western shell: the emission of dust in the inter-clump medium of shocked molecular clouds, the emission of dust in evaporating flows of molecular clouds engulfed by hot gas, and the emission of dust of nearby molecular clouds illuminated by radiative shocks.

Lee, Ho-Gyu; Moon, Dae-Sik [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Koo, Bon-Chul [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Onaka, Takashi; Sakon, Itsuki [Department of Astronomy, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Jeong, Woong-Seob; Shinn, Jong-Ho, E-mail: hglee@astro.utoronto.ca, E-mail: moon@astro.utoronto.ca, E-mail: koo@astrohi.snu.ac.kr, E-mail: onaka@astron.s.u-tokyo.ac.jp, E-mail: isakon@astron.s.u-tokyo.ac.jp, E-mail: jeongws@kasi.re.kr, E-mail: jhshinn@kasi.re.kr [Korea Astronomy and Space Science Institute, 776, Daedeok-daero, Yuseong-gu, Daejeon 305-348 (Korea, Republic of)

2011-10-10

173

Transition to the radiative phase in supernova remnant evolution  

NASA Astrophysics Data System (ADS)

The evolution of a supernova remnant (SNR) through the transition from an adiabatic Sedov-Taylor blastwave to a radiative pressure-driven snowplow phase is studied through a series of one-, two- and three-dimensional hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations. This transition is marked by a catastrophic collapse of the postshock gas, forming a thin, dense shell behind the forward shock. Previous studies have shown that the thin, dense shell of gas present during this transition is susceptible to both radiative and dynamical instabilities. One-dimensional HD studies indicate the presence of a radial oscillation between the forward shock and the thin shell, due to the rapid cooling of the gas in the immediate postshock region. Two-dynamical HD simulations of this transition indicate the presence of violent dynamical instabilities that alter the initially spherical morphology of the blastwave, specifically, the Pressure-driven Thin Shell Overstability (PDTSO) and the Non-linear Thin Shell Instability (NTSI). Hydrodynamical simulations, by their very nature, ignore the effects of magnetic forces on moving fluids. In general, interstellar magnetic fields will be weak enough that their effects may be safely ignored. However, the transition to the radiative phase in SNR evolution is often triggered when the blastwave interacts with dense clouds of gas in the interstellar medium (ISM). The resulting compression of the gas during the transition also compresses the magnetic fields in the cloud, possibly enhancing the field sufficiently to play a role in the further evolution of the SNR. To better understand the role of the NTSI during the transition, and to study the effects of magnetic fields on the instability itself, we performed idealized two- and three-dimensional MHD simulations. The results of the two-dimensional simulations were found to depend strongly on the orientation of the ambient magnetic field when the postshock field is dynamically significant. To accurately model the evolution of the NTSI, only three-dimensional simulations will suffice. However, the three-dimensional simulations performed were unable to run long enough to detect characteristic exponential growth of the NTSI, but initial studies indicate the presence of the instability.

Wright, Eric Boyd

1999-11-01

174

Relation between synchrotron radio surface brightness and radius for supernova remnants  

SciTech Connect

When a supernova remnant expands, hot gas that is swept up will compress density fluctuations in the interstellar medium, and shock waves will be generated in them. The resulting compression of the magnetic field and relativistic particles in the fluctuations can cause the fluctuations to produce nonthermal radio emission whose combined power is comparable with that observed in supernova remnants. The fluctuations will be strongly compressed in a thin layer behind the shock front, accompanied by radiative cooling. Cooling of the fluctuations because of their high gas density may also occur during the adiabatic expansion phase of the remnant. In the model of compressed fluctuations the relation between the surface brightness of the nonthermal radio emission and the radius of the remnant takes the form ..sigma../sub ..nu../proportionalR/sup -17/4/, which is similar to that inferred from the statistics of well-observed remnants. The thickness of the radio envelope of supernova remnants and their polarization are discussed.

Bychkov, K.V.

1978-07-01

175

The first VLBI image of the young, oxygen-rich supernova remnant in NGC 4449  

NASA Astrophysics Data System (ADS)

We report on sensitive 1.4-GHz VLBI radio observations of the unusually luminous supernova remnant SNR 4449-1 in the galaxy NGC 4449, which gave us the first well-resolved image of this object. The remnant's radio morphology consists of two approximately parallel bright ridges, suggesting similarities to the barrel shape seen for many older Galactic supernova remnants or possibly to SN 1987A. The angular extent of the remnant is 65 40 mas, corresponding to (3.7 2.3) 1018 (D/3.8 Mpc) cm. We also present a new, high signal-to-noise ratio optical spectrum. By comparing the remnant's linear size to the maximum velocities measured from optical lines, as well as using constraints from historical images, we conclude that the supernova explosion occurred between 1905 and 1961, likely around 1940. The age of the remnant is therefore likely 70 yr. We find that SNR 4449-1's shock wave is likely still interacting with the circumstellar rather than interstellar medium.

Bietenholz, M. F.; Bartel, N.; Milisavljevic, D.; Fesen, R. A.; Challis, P.; Kirshner, R. P.

2010-12-01

176

HST Proper-Motion Measurements of the Supernova Remnant E0102-7219  

NASA Astrophysics Data System (ADS)

We present results from a proper-motion study of the young supernova remnant E0102-7219 (hereafter E0102) in the Small Magellanic Cloud (SMC). E0102 is a member of a class of objects known as oxygen-rich supernova remnants, due to the strong oxygen signatures seen in its spectra, and the absence of hydrogen and helium. Previous studies have inferred that the progenitor of E0102 was most likely a high-mass Wolf-Rayet star that underwent considerable mass loss prior to the supernova event. The ejecta from this supernova are fast-moving (V > 1000 km/s) and emit due to heating from the reverse shock. New optical images were obtained with the Advanced Camera for Surveys on the Hubble Space Telescope (HST) in 2003. These were combined with data taken in 1995 from the Wide Field Planetary Camera 2. Using these two epochs spaced 9 years apart, we directly measure the expansion rate of this supernova remnant for the first time at visible wavelengths. Measuring the expansion rate allows us to determine how long ago the star exploded and where it was located. Because some theories suggest stellar explosions of this type may form a black hole, these results may bear on the location of the black hole, the progenitor's type, and the mass loss history prior to the supernova explosion.

Finkelstein, S. L.; Morse, J. A.; Green, J. C.; COS Science

2004-12-01

177

Observability and diagnostics in the X-ray band of shock-cloud interactions in supernova remnants  

Microsoft Academic Search

Context. X-ray emitting features originating from the interaction of supernova shock waves with small interstellar gas clouds are revealed in many X-ray observations of evolved supernova remnants (e.g., Cygnus Loop and Vela), but their interpretation is not straightforward. Aims: We develop a self-consistent method for the analysis and interpretation of shock-cloud interactions in middle-aged supernova remnants, which can provide the

S. Orlando; F. Bocchino; M. Miceli; X. Zhou; F. Reale; G. Peres

2010-01-01

178

DEM L241, a Supernova Remnant Containing a High-mass X-Ray Binary  

NASA Astrophysics Data System (ADS)

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 ?

Seward, F. D.; Charles, P. A.; Foster, D. L.; Dickel, J. R.; Romero, P. S.; Edwards, Z. I.; Perry, M.; Williams, R. M.

2012-11-01

179

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 s1, while the emission from the head and tongue amounts for only ~1.5 1031 erg s1. 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 yr1 and ?? = 0.013 0.003 arcsec yr1. With an implied velocity of 500 km s1, 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

180

X-ray emission from the remnant of a carbon deflagration supernova - SN 1572 (Tycho)  

SciTech Connect

A spherically symmetric hydrodynamic code is used to study the evolution of a young supernova remnant on the basis of a carbon deflagration model for type Ia supernovae. The nonequilibrium X-ray emission has been determined for the elemental composition of the model. The discrepancy between the derived intensity of the Fe D-alpha line blend and the observed value is eliminated by assuming that the stratification of the elemental composition in the supernova ejecta is partially removed by mixing. 59 references.

Itoh, H.; Masai, K.; Nomoto, K.

1988-11-01

181

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

SciTech Connect

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. 41 references.

Dwek, E.; Petre, R.; Szymkowiak, A.; Rice, W.L.

1987-09-01

182

X-Ray-Optical-Radio Observations of a Resolved Supernova Remnant in NGC 6822  

Microsoft Academic Search

The supernova remnant (SNR) Ho 12, in the center of the dwarf irregular galaxy NGC 6822, was previously observed at X-ray, optical, and radio wavelengths. By using archival Chandra and ground-based optical data, we found that the SNR is spatially resolved in X-rays and optical. In addition, we obtained a ~5\\

Albert K. H. Kong; Lornt O. Sjouwerman; Benjamin F. Williams

2004-01-01

183

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

184

Thermal and Nonthermal X-ray Emission from the Forward Shock in Tycho's Supernova Remnant.  

National Technical Information Service (NTIS)

We present Chandra CCD images of Tycho's supernova remnant that delineate its outer shock, seen as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clum...

U. Hwang A. Decourchelle S. S. Holt R. Petre

2002-01-01

185

Thermal and Nonthermal X-Ray Emission from the Forward Shock in Tycho's Supernova Remnant  

Microsoft Academic Search

We present Chandra X-ray images of Tycho's supernova remnant that delineate its outer shock as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clumpy and have reached near the forward shock at numerous locations. Most of the X-ray spectra that

Una Hwang; Anne Decourchelle; Stephen S. Holt; Robert Petre

2002-01-01

186

AKARI and BLAST Observations of the Cassiopeia A Supernova Remnant and Surrounding Interstellar Medium  

Microsoft Academic Search

We use new large area far infrared maps ranging from 65 to 500 mum 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 \\

B. Sibthorpe; P. A. R. Ade; J. J. Bock; E. L. Chapin; M. J. Devlin; S. Dicker; M. Griffin; J. O. Gundersen; M. Halpern; P. C. Hargrave; D. H. Hughes; W.-S. Jeong; H. Kaneda; J. Klein; B.-C. Koo; H.-G. Lee; G. Marsden; P. G. Martin; P. Mauskopf; D.-S. Moon; C. B. Netterfield; L. Olmi; E. Pascale; G. Patanchon; M. Rex; A. Roy; D. Scott; C. Semisch; M. D. P. Truch; C. Tucker; G. S. Tucker; M. P. Viero; D. V. Wiebe

2010-01-01

187

Discovery of Molecular Shells Associated with Supernova Remnants. I. Kesteven 69  

Microsoft Academic Search

Supernova remnant (SNR) Kes 69 is morphologically characterized by brightened radio, infrared, and X-ray emission on the southeastern rim, with the 1720 MHz OH masers detected in the northeastern and southeastern regions at various local standard rest (LSR) velocities. We have performed a millimeter observation in CO and HCO+ lines toward Kes 69. From the northeastern compact maser region, 12CO

Xin Zhou; Yang Chen; Yang Su; Ji Yang; Il-Gyo Jeong; Chun-Guang Zhang

2009-01-01

188

Optical emission from a fast shock wave: The remnants of Tycho's supernova and SN 1006  

Microsoft Academic Search

The faint optical filaments in Tycho's supernova remnant appear to be emission from a shock front moving at 5600 km s⁻¹. The intensity of the hydrogen lines, the absence of forbidden lines of heavy elements in the spectrum, and the width of the filaments are explained by a model in which a collisionless shock wave is moving into partially neutral

R. A. Chevalier; J. C. Raymond

1978-01-01

189

XMM-Newton Observations of the Galactic Supernova Remnant CTB 109 (G109.1-1.0)  

NASA Astrophysics Data System (ADS)

We present the analysis of the X-ray Multimirror Mission (XMM-Newton) European Photon Imaging Camera (EPIC) data of the Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0). CTB 109 is associated with the anomalous X-ray pulsar (AXP) 1E 2259+586 and has an unusual semicircular morphology in both the X-ray and the radio and an extended X-ray bright interior region known as the ``Lobe.'' The deep EPIC mosaic image of the remnant shows no emission toward the west where a giant molecular cloud complex is located. No morphological connection between the Lobe and the AXP is found. We find remarkably little spectral variation across the remnant given the large intensity variations. All spectra of the shell and the Lobe are well fitted by a single-temperature nonequilibrium ionization model for a collisional plasma with solar abundances [kT~0.5-0.7 keV, ?=nedt~(1-4)1011 s cm-3, NH~(5-7)1021 cm-2]. There is no indication of nonthermal emission in the Lobe or the shell. We conclude that the Lobe originated from an interaction of the SNR shock wave with an interstellar cloud. Applying the Sedov solution for the undisturbed eastern part of the SNR and assuming full equilibration between the electrons and ions behind the shock front, the SNR shock velocity is derived as vs=720+/-60 km s-1, the remnant age as t=(8.8+/-0.9)103d3 yr, the initial energy as E0=(7.4+/-2.9)1050d2.53 ergs, and the preshock density of the nuclei in the ambient medium as n0=(0.16+/-0.02)d-0.53 cm-3, at an assumed distance of D=3.0d3 kpc. Assuming that CTB 109 and 1E 2259+586 are associated, these values constrain the age and the environment of the progenitor of the SNR and the pulsar.

Sasaki, Manami; Plucinsky, Paul P.; Gaetz, Terrance J.; Smith, Randall K.; Edgar, Richard J.; Slane, Patrick O.

2004-12-01

190

Influence of Cosmic-ray Acceleration Processes on the Observable Properties of Supernova Remnant Models.  

NASA Astrophysics Data System (ADS)

We present numerical models for supernova remnant evolution, performed with a hydro-dynamical code SUPREMNA. The code accounts for electron thermal conduction, electron and ion tem-perature equilibration and includes self-consistent calculations of time-dependent ionization processes in the shocked plasma. In this study we present an additional modification of the package: introduction of cosmic-ray acceleration processes. We employ two-fluid approxima-tion, which allows us to take into account self-consistently thermal energy losses to relativistic particles. We investigate the influence of the relevant parameters on the dynamical and phys-ical properties of the modeled remnants and on the corresponding simulated X-ray spectra. We compare the properties of the models with the observed features of some young supernova remnants such as Tycho and SN1006.

Kosenko, Daria; Blinnikov, Sergey

191

Suzaku Results of SN 1006: Chemical Abundances of the ''youngest'' Galactic Type Ia Supernova Remnant  

SciTech Connect

SN 1006 is one of the supernova remnants (SNR) recorded in the Japanese diary 'Meigetsuki'. From the historical records including Meigetsuki, we conclude that SN 1006 was the brightest type Ia supernova remnant. We report on the observations of SN 1006 with the X-ray Imaging Spectrometers (XIS) on board the 5-th Japanese X-ray satellite Suzaku. We found that the ionization age of SN 1006 is the youngest among any Galactic SNRs, hence is the best SNR to study early phase of type Ia. In the X-ray spectrum, we found the K-shell emission lines from heavy elements, in particular that from iron, for the first time. The X-ray emitting plasma is highly overabundant in heavy elements, hence are likely due to ejecta. The abundance pattern agrees well to the theoretical prediction of type Ia supernova.

Koyama, Katsuji [Department of physics Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)

2008-05-21

192

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

193

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

194

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.

195

Discovery of 28 pulsars using new techniques for sorting pulsar candidates  

NASA Astrophysics Data System (ADS)

Modern pulsar surveys produce many millions of candidate pulsars, far more than can be individually inspected. Traditional methods for filtering these candidates, based upon the signal-to-noise ratio of the detection, cannot easily distinguish between interference signals and pulsars. We have developed a new method of scoring candidates using a series of heuristics which test for pulsar-like properties of the signal. This significantly increases the sensitivity to weak pulsars and pulsars with periods close to interference signals. By applying this and other techniques for ranking candidates from a previous processing of the Parkes Multi-beam Pulsar Survey, 28 previously unknown pulsars have been discovered. These include an eccentric binary system and a young pulsar which is spatially coincident with a known supernova remnant.

Keith, M. J.; Eatough, R. P.; Lyne, A. G.; Kramer, M.; Possenti, A.; Camilo, F.; Manchester, R. N.

2009-05-01

196

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

NASA Astrophysics Data System (ADS)

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 discernible X-ray shell. In addition, X-ray-bright knots dot W44's image. The spectral analysis of the Chandra data shows 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-cloud 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-cloud 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 prompt 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.

2004-08-01

197

Radio properties of three young supernova remnants in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

Radio images of N132D, N103B, and 0519-690 have been made with the Australian Telescope. These three prominent young Supernova remnants (SNRs) in the Large Magellanic Cloud (LMC) have significantly different optical properties: N132D is oxygen rich and probably had a massive progenitor similar to Cas A; N103B, on the edge of a massive H II region complex, was probably also from a masssive star; on the other hand, isolated Balmer-dominated 0519-690 was probably from a low-mass Type Ia supernova. All three remnants show the characteristics shell structure with some clumpiness. Although the polarimetric data are not complete for all three, the results are compatible with a small net radial orientation of the magnetic fields in these young remnants. We suggest that N132D is older and probably somewhat more energetic and/or massive than Cas A. N103B appears to be a younger version of N132D, while 0519-690 is less luminous and not unlike the remnants of low-mass super-novae seen in the Milky Way.

Dickel, John R.; Milne, D. K.

1995-01-01

198

Magnetic amplification and electron acceleration in supernova remnant shocks  

NASA Astrophysics Data System (ADS)

Supernova remnant (SNR) shocks are the main candidates for the acceleration of galactic cosmic rays (CRs). This assessment is supported by the success of the diffusive shock acceleration (DSA) mechanism to reproduce power-law energy distributions close to the ones of CRs. However, and despite extensive efforts, at present the connection between galactic CRs and SNR shocks has not been fully demonstrated, neither from theoretical nor from observational point of view. The situation is different for the case of accelerated electrons. X-ray observations of SNRs show the existence of thin non-thermal rims, which are interpreted as synchrotron emission by TeV electrons accelerated in SNR shocks. Also, the rapid variability and thinness of the rims (which depend on the synchrotron cooling time of the electrons) have allowed to estimate the strength of the magnetic field, suggesting amplitudes 100 times larger than the typical 3muG field in the ISM. Unveiling the mechanisms producing these electron acceleration and magnetic amplification are essential steps to understanding the physics of particle acceleration in SNRs, and are the subjects of this dissertation. In the first part of this thesis (chapters 2 and 3), we explore the idea, first proposed by Bell (2004), of the magnetic field amplification being driven by the CRs themselves. In chapter 2 we use particle-in-cell (PIC) plasma simulations to study the cosmic ray current-driven instability (CRCD), which in the last years has been the main candidate to explain magnetic amplification in SNRs. This instability consists of growing Alfvenic waves driven by the electric current of CRs streaming along the magnetic field in the upstream medium of the shocks. We confirm the existence of this instability in the kinetic regime, and determine its saturation mechanism. We find that the field growth saturates due to the deflection of the CR trajectories in the amplified field, and that, under optimistic assumptions, a maximum amplification factor of 10 would be expected in the upstream medium of SNR shocks. When the field compression at the shock is considered, the field may increase by an extra factor of 4. Since the amplification factor we found is an upper limit, we conclude that the CRCD instability alone would not be enough to account for the factor of 100 inferred from the X-ray observations. In chapter 3 we study the possibility of magnetic amplification beyond the saturation of the CRCD instability. We find that an extra field growth is possible due to a new instability, which we term perpendicular current-driven instability (PCDI). The PCDI consists of purely growing compressional waves, excited by the CR electric current perpendicular to the field. The PCDI would be driven by the lowest energy CRs, which are rather confined to the shock vicinity, and would act on a field previously amplified by the CRCD instability. We find that the PCDI would provide an additional amplification factor of (c/2/ vsh)1/2 (where c is the speed of light and vsh is the shock velocity), and that in general it would reach maximum magnetic fields magnitudes a factor of 3 below energy equipartition with the CRs. Thus, if CRs are assumed to carry 10% of the shock ram pressure energy, then this saturation criterion would imply MA ? 10. In chapter 4 we describe our study of electron acceleration in SNR shocks, using ab-initio PIC simulations extending to high ion to electron mass ratios. We find that, for quasi-perpendicular shocks, electrons can be efficiently accelerated to non-thermal energies due to the presence of whistler waves in the foot of the shocks. This mechanism would provide acceleration with power-law spectral indices of 3--4. The acceleration, however, would require the Alfvenic Mach number of the shock to be ? 14. Thus, if this were to be the process responsible for electron injection in SNR shocks, it would strongly constrain the upstream field amplification, placing a lower limit such that MA ? 14, which would be consistent with the PCDI saturation limit. Our results r

Riquelme, Mario A.

199

Evidence for a possible black hole remnant in the Type IIL Supernova 1979C  

NASA Astrophysics Data System (ADS)

We present an analysis of archival X-ray observations of the Type IIL supernova SN 1979C. We find that its X-ray luminosity is remarkably constant at (6.5 0.1) 10 38 erg s -1 over a period of 12 years between 1995 and 2007. The high and steady luminosity is considered as possible evidence for a stellar-mass (5-10 M?) black hole accreting material from either a supernova fallback disk or from a binary companion, or possibly from emission from a central pulsar wind nebula. We find that the bright and steady X-ray light curve is not consistent with either a model for a supernova powered by magnetic braking of a rapidly rotating magnetar, or a model where the blast wave is expanding into a dense circumstellar wind.

Patnaude, D. J.; Loeb, A.; Jones, C.

2011-04-01

200

Determining Progenitors of Young Supernova Remnants from Their Fe K-Shell Emission  

NASA Astrophysics Data System (ADS)

Young Supernova Remnants (SNRs) retain crucial information about their explosion and nucleosynthesis mechanisms. However, interactions with the surrounding circumstellar and interstellar medium can conceal these data and so it is not unusual that even the basic progenitor type (i.e., Ia or core-collapse) of a remnant remains controversial. Here we propose a new method to discriminate the progenitors solely using the Fe K-shell X-ray spectrum. We systematically analyzed Suzaku and Chandra observations of young ejecta-dominated SNRs to determine the intensity and centroid of the Fe-K emission lines. We found that the Fe ejecta in Type Ia SNRs are commonly less ionized than those in core-collapse SNRs. It was found, moreover, that luminosity and centroid of the Fe-K emission are well correlated among each group of Type Ia or core-collapse remnants, and that the more luminous remnants tend to be more highly ionized. These results may reflect the pre-explosion density of the remnants. Evidence of overionization was observed only in core-collapse SNRs, implying their origin to be related to interaction with stellar wind material. Our method can potentially be utilized in systematic studies of extragalactic SNRs with future missions, such as AXSIO, that have high-resolution imaging and spectroscopic capabilities. This will help study, for example, the supernova rate in different ISM environments.

Yamaguchi, Hiroya; Smith, R. K.; Slane, P. O.

2013-04-01

201

SN 1957D in M83: A Young Supernova Remnant Emerges  

NASA Astrophysics Data System (ADS)

We report recent multi-wavelength observations of the remnant from SN 1957D, a core-collapse supernova in M83 and one of six SNe M83 has produced in the past century. SN 1957D was recovered as a radio SNR by Cowan & Branch (1983), and optically by Long et al. (1988). We have recently detected it for the first time in X-rays, in a long observation from Chandra. New HST WFC3 images resolve the SNR from the complex surrounding emission and reveal the local star field. The optical flux from SN 1957D is dominated by broad [O III] emission lines, the signature of fast-moving SN ejecta. The [O III] flux dropped precipitously between 1989 and 1991; a series of subsequent observations indicates continuing but more gradual decline. The width of the broad lines has remained roughly constant at about 3000 km/s (FWHM). At radio wavelengths, observations over the period 1990-2011 show a decline rate S? t-3.9, far steeper than the rate observed between 1984 and 1990. Such evolution suggests early expansion into a circumstellar medium dominated by wind material from the progenitor, followed by a steeper decline as the blast wave overruns the edge of the wind material. The X-ray luminosity (0.3 - 10 keV) is 2.0 E37 erg/s, with a relatively hard spectrum. We cannot distinguish between a power law (indicating a probable pulsar and surrounding nebula) vs a hot thermal spectrum from the blast wave. However, the absorption is relatively high, NH 2 E22 cm-2, suggesting a dense local environment. Photometry of the local stellar population around SN 1957D, using HST WFC3 images, indicates a log(age) 7.3 and (remaining) stars up to about 11 M. This research is supported primarily by NASA through Chandra Grant G01-12115; PFW acknowledges additional support from NSF Grant AST-0908566.

Winkler, P. Frank; Long, K. S.; Blair, W. P.; Soria, R.; Godfrey, L. E. H.; Kuntz, K. D.; Plucinsky, P. P.; Whitmore, B. C.

2012-05-01

202

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

203

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

204

FERMI LARGE AREA TELESCOPE DETECTION OF THE YOUNG SUPERNOVA REMNANT TYCHO  

SciTech Connect

After almost three years of data taking in sky-survey mode, the Fermi Large Area Telescope has detected {gamma}-ray emission toward Tycho's supernova remnant (SNR). The Tycho SNR is among the youngest remnants in the Galaxy, originating from a Type Ia Supernova in AD 1572. The {gamma}-ray integral flux from 400 MeV up to 100 GeV has been measured to be (3.5 {+-} 1.1{sub stat} {+-} 0.7{sub syst}) Multiplication-Sign 10{sup -9} cm{sup -2} s{sup -1} with a photon index of 2.3 {+-} 0.2{sub stat} {+-} 0.1{sub syst}. A simple model consistent with TeV, X-ray, and radio data is sufficient to explain the observed emission as originating from {pi}{sup 0} decays as a result of cosmic-ray acceleration and interaction with the ambient medium.

Giordano, F. [Dipartimento di Fisica, 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Naumann-Godo, M.; Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Bechtol, K.; Funk, S.; Lande, J.; Tanaka, T.; Uchiyama, Y. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Mazziotta, M. N.; Raino, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, 70126 Bari (Italy); Tibolla, O., E-mail: francesco.giordano@ba.infn.it, E-mail: Melitta.Naumann-Godo@cea.fr [Institut fuer Theoretische Physik and Astrophysik, Universitaet Wuerzburg, D-97074 Wuerzburg (Germany)

2012-01-15

205

High Energy Observational Investigations of Supernova Remnants and their Interactions with Surroundings  

NASA Astrophysics Data System (ADS)

Here we review the effort of Fermi Asian Network (FAN) in exploring the supernova remnants (SNRs) with state-of-art high energy observatories, including Fermi Gamma-ray Space Telescope and Chandra X-ray Observatory, in the period of 2011- 2012. Utilizing the data from Fermi LAT, we have discovered the GeV emission at the position of the Galactic SNR Kes 17 which provides evidence for the hadronic acceleration. Our study also sheds light on the propagation of cosmic rays from their acceleration site to the intersteller medium. We have also launched an identification campaign of SNR candidates in the Milky Way, in which a new SNR G308.3-1.4 have been uncovered with our Chandra observation. Apart from the remnant, we have also discovered an associated compact object at its center. The multiwavelength properties of this X-ray source suggest it can possibly be the compact binary that survived a supernova explosion.

Hui, Chung-Yue

2013-09-01

206

Fermi Large Area Telescope Detection of the Young Supernova Remnant Tycho  

NASA Astrophysics Data System (ADS)

After almost three years of data taking in sky-survey mode, the Fermi Large Area Telescope has detected ?-ray emission toward Tycho's supernova remnant (SNR). The Tycho SNR is among the youngest remnants in the Galaxy, originating from a Type Ia Supernova in AD 1572. The ?-ray integral flux from 400 MeV up to 100 GeV has been measured to be (3.5 1.1stat 0.7syst) 10-9 cm-2 s-1 with a photon index of 2.3 0.2stat 0.1syst. A simple model consistent with TeV, X-ray, and radio data is sufficient to explain the observed emission as originating from ?0 decays as a result of cosmic-ray acceleration and interaction with the ambient medium.

Giordano, F.; Naumann-Godo, M.; Ballet, J.; Bechtol, K.; Funk, S.; Lande, J.; Mazziotta, M. N.; Rain, S.; Tanaka, T.; Tibolla, O.; Uchiyama, Y.

2012-01-01

207

Observation of Supernova Remnant IC 443 with the Fermi Large Area Telescope  

Microsoft Academic Search

We report observation of the supernova remnant (SNR) IC 443 (G189.1+3.0) with the Fermi Gamma-ray Space Telescope Large Area Telescope (LAT) in the energy band between 200 MeV and 50 GeV. IC 443 is a shell-type SNR with mixed morphology located off the outer Galactic plane where high-energy emission has been detected in the X-ray, GeV and TeV gamma-ray bands.

A. A. Abdo; M. Ackermann; M. Ajello; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; B. Berenji; R. D. Blandford; E. D. Bloom; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; . elik; A. Chekhtman; C. C. Cheung; J. Chiang; A. N. Cillis; S. Ciprini; R. Claus; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; S. Cutini; C. D. Dermer; A. de Angelis; F. de Palma; E. do Couto e. Silva; P. S. Drell; A. Drlica-Wagner; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; W. B. Focke; P. Fortin; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; G. Giavitto; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; A. K. Harding; M. Hayashida; R. E. Hughes; M. S. Jackson; G. Jhannesson; A. S. Johnson; T. J. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; J. Kndlseder; M. L. Kocian; M. Kuss; J. Lande; L. Latronico; S.-H. Lee; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; G. M. Madejski; A. Makeev; M. N. Mazziotta; C. Meurer; P. F. Michelson; W. Mitthumsiri; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; T. Nakamori; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; J. H. Panetta; D. Parent; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rain; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; 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; J. D. Scargle; C. Sgr; E. J. Siskind; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; M. S. Strickman; A. W. Strong; D. J. Suson; H. Tajima; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; A. Van Etten; V. Vasileiou; C. Venter; N. Vilchez; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; T. Ylinen; M. Ziegler

2010-01-01

208

X-ray\\/Optical\\/Radio Observations of a Resolved Supernova Remnant in NGC 6822  

Microsoft Academic Search

The supernova remnant (SNR), Ho 12, in the center of the dwarf irregular\\u000agalaxy NGC 6822 was previously observed at X-ray, optical, and radio\\u000awavelengths. By using archival Chandra and ground-based optical data, we found\\u000athat the SNR is spatially resolved in X-rays and optical. In addition, we\\u000aobtained a ~5\\

Albert K. H. Kong; Lornt O. Sjouwerman; Benjamin F. Williams

2004-01-01

209

Exploring the Diffuse X-ray Emission of Supernova Remnant Kesteven 69 with XMM-Newton  

NASA Astrophysics Data System (ADS)

We have investigated the X-ray emission from the shock-heated plasma of the Galactic supernova remnant Kesteven 69 with XMM-Newton. Assuming the plasma is at collisional ionization equilibrium, a plasma temperature and a column absorption are found to be kT ~ 0.62 keV and NH ~ 2.85 10^22 cm-2 respectively by imaging spectroscopy. Together with the deduced emission measure, we place constraints on its Sedov parameters.

Seo, Kyoung-Ae; Hui, Chung Yue

2013-06-01

210

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

Microsoft Academic Search

We explore the importance of anisotropic thermal conduction in the evolution\\u000aof supernova remnants via numerical simulations. The mean temperature of the\\u000abubble of hot gas is decreased by a factor of ~3 compared to simulations\\u000awithout thermal conduction, together with an increase in the mean density of\\u000ahot gas by a similar factor. Thus, thermal conduction greatly reduces the

David A. Tilley; Dinshaw S. Balsara

2006-01-01

211

High resolution observations of compact radio sources in the directions of supernova remnants  

Microsoft Academic Search

VLBI observations of five compact radio sources located in the directions of supernova remnants (SNRs) are reported which were performed at a wavelength of 2.8 or 3.7 cm with resolutions of the order of 1 milliarcsec. The sources observed (and the SNRs near them) include CL4 (the Cygnus Loop), G127.11 plus 0.54 (G127.1 plus 0.5), G74.84 plus 1.22 (G74.9 plus

B. J. Geldzahler

1978-01-01

212

Thermal and Nonthermal Emission from the Forward Shock in Tycho's Supernova Remnant  

Microsoft Academic Search

We present Chandra X-ray images of Tycho's supernova remnant that delineate\\u000aits outer shock as a thin, smooth rim along the straight northeastern edge and\\u000amost of the circular western half. The images also show that the Si and S\\u000aejecta are highly clumpy, and have reached near the forward shock at numerous\\u000alocations. Most of the X-ray spectra that

Una Hwang; Anne Decourchelle; Stephen S. Holt; Robert Petre

2002-01-01

213

Supernova remnants and the origin of cosmic radiation: evidence from low-energy gamma rays  

Microsoft Academic Search

Our model, in which cosmic rays are accelerated by shocks in supernova remnants (SNR) and then propagate by diffusion through the galaxy, has been developed and applied to the case of the low-energy (E? ? 10 GeV) diffuse gamma ray background. Attention is given to the well-known GeV-excess problem, i.e. the gamma ray spectrum from the inner galaxy is flatter

A D Erlykin; A W Wolfendale

2002-01-01

214

Non-equilibrium ionization X-ray emission from supernova remnants  

Microsoft Academic Search

Observed X-ray spectra of young supernova remnants (SNR) are discussed with respect to the capabilities of current nonequilibrium ionization models (NIM). The HEAO-2 satellite has detected He-like ionization of several heavy elements and excited Fe, O, Ne, Mg, Ar and Ca lines. Lyman-alpha and -beta, O VIII triplets and Fe XVII lines (Puppis A) have also been recorded. NIM models

J. M. Shull

1983-01-01

215

Supernova Remnants in the Sedov Expansion Phase: Thermal X-Ray Emission  

Microsoft Academic Search

Improved calculations of X-ray spectra for supernova remnants (SNRs) in the\\u000aSedov-Taylor phase are reported, which for the first time include reliable\\u000aatomic data for Fe L-shell lines. This new set of Sedov models also allows for\\u000aa partial collisionless heating of electrons at the blast wave and for energy\\u000atransfer from ions to electrons through Coulomb collisions. X-ray emission

Kazimierz J. Borkowski; William J. Lyerly; Stephen P. Reynolds

2000-01-01

216

Radio observations of the Crab-like supernova remnant 3C 58. I. Total intensity observations  

Microsoft Academic Search

The Crab-like supernova remnant 3C 58 was observed with the VLA at frequencies of 1446 and 4886 MHz, with resolutions of 2.0 and 2.45 arcsec, respectively. It is found that 3C 58 has a considerably larger extent than previously realized, particularly at the eastern and western edges and above and below the central bulge. Some parts of the periphery are

Stephen P. Reynolds; Hugh D. Aller

1988-01-01

217

Dust Destruction in Type Ia Supernova Remnants in the Large Magellanic Cloud  

Microsoft Academic Search

We present first results from an extensive survey of Magellanic Cloud supernova remnants (SNRs) with the Spitzer Space Telescope. We describe IRAC and MIPS imaging observations at 3.6, 4.5, 5.8, 8, 24, and 70 mum of four Balmer-dominated Type Ia SNRs in the Large Magellanic Cloud (LMC): DEM L71 (0505-67.9), 0509-67.5, 0519-69.0, and 0548-70.4. None was detected in the four

Kazimierz J. Borkowski; Brian J. Williams; Stephen P. Reynolds; William P. Blair; Parviz Ghavamian; Ravi Sankrit; Sean P. Hendrick; Knox S. Long; John C. Raymond; R. Chris Smith; P. Frank Winkler

2006-01-01

218

Crushing of interstellar gas clouds in supernova remnants. II. X-ray emission  

Microsoft Academic Search

Context: .X-ray observations of evolved supernova remnants (e.g. the Cygnus loop and the Vela SNRs) reveal emission originating from the interaction of shock waves with small interstellar gas clouds. Aims: .We study and discuss the time-dependent X-ray emission predicted by hydrodynamic modeling of the interaction of a SNR shock wave with an interstellar gas cloud. The scope includes: 1) to

S. Orlando; F. Bocchino; G. Peres; F. Reale; T. Plewa; R. Rosner

2006-01-01

219

Hard X-ray and Gamma-Ray Emission from Shell Supernova Remnants  

Microsoft Academic Search

Strong shock waves in shell supernova remnants have been shown to be capable of accelerating particles to energies in excess of 100 TeV. Electrons of these energies produce hard X-ray synchrotron emission and TeV inverse-Compton emission by upscattering cosmic microwave background photons. However, bremsstrahlung from suprathermal, nonrelativistic electrons can also produce hard X-ray emission. I calculate model X-ray and gamma-ray

S. P. Reynolds

1998-01-01

220

Modified Equipartition Calculation for Supernova Remnants. Cases ? = 0.5 and ? = 1  

NASA Astrophysics Data System (ADS)

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.; Vukoti?, B.

2013-11-01

221

X-Ray Emission-Line Imaging and Spectroscopy of Tycho's Supernova Remnant  

Microsoft Academic Search

We present X-ray images of Tycho's supernova remnant in emission-line features of Mg, Si, S, Ar, Ca, and Fe, plus the continuum, using data obtained by the imaging spectrometers on board the Advanced Satellite for Cosmology and Astrophysics (ASCA). All the images show the shell-like morphology characteristic of previously obtained broadband X-ray images, but they are clearly distinct from each

Una Hwang; Eric V. Gotthelf

1997-01-01

222

Magnetic Field Amplification in Tycho and other Shell-type Supernova Remnants  

Microsoft Academic Search

It is shown that amplification of the magnetic field in supernova remnants\\u000a(SNRs) occurs in all six objects where morphological measurements are presently\\u000aavailable in the hard X-ray continuum at several keV. For the three\\u000aarchetypical objects (SN 1006, Cas A and Tycho's SNR) to which nonlinear\\u000atime-dependent acceleration theory has been successfully applied up to now, the\\u000aglobal theoretical

H. J. Voelk; E. G. Berezhko; L. T. Ksenofontov

2004-01-01

223

Radio to Gamma-Ray Emission from Shell-Type Supernova Remnants: Predictions from Nonlinear Shock Acceleration Models  

Microsoft Academic Search

Supernova remnants (SNRs) are widely believed to be the principal source of Galactic cosmic rays, produced by diffusive shock acceleration in the environs of the remnant's expanding blast wave. Such energetic particles can produce gamma rays and lower energy photons via interactions with the ambient plasma. The recently reported observation of TeV gamma rays from SN 1006 by the Collaboration

Matthew G. Baring; Donald C. Ellison; Stephen P. Reynolds; Isabelle A. Grenier; Philippe Goret

1999-01-01

224

Thermal X-Ray Emission from Shocked Ejecta in Type Ia Supernova Remnants: Prospects for Explosion Mechanism Identification  

Microsoft Academic Search

The explosion mechanism behind Type Ia supernovae is a matter of continuing debate. The diverse attempts to identify or at least constrain the physical processes involved in the explosion have been only partially successful so far. In this paper we propose to use the thermal X-ray emission from young supernova remnants (SNRs) originating in Type Ia events to extract relevant

Carles Badenes; Eduardo Bravo; Kazimierz J. Borkowski; Inmaculada Domnguez

2003-01-01

225

Effect of stellar structure on supernova remnant evolution  

SciTech Connect

One-dimensional hydrodynamic calculations have been done of 1E51 erg explosions in 15M/sub sun/ stars. A steep external density gradient to the pre-supernova model of Weaver et al was appended with the results: (1) the outer shock wave decelerates throughout the pre-Sedov phase, (2) the expanding stellar envelope and the shocked interstellar material are Rayleigh-Taylor stable until the Sedov phase, and (3) steep internal density gradients are R-T unstable during the early expansion and may be the source of high velocity knots seen in Cas A.

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

1980-01-01

226

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

NASA Astrophysics Data System (ADS)

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 24 ?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.; Loi, Shyeh T.; Murphy, Tara; Miller, Jon M.; Maitra, Dipankar; Gltekin, 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

2013-04-01

227

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

NASA Astrophysics Data System (ADS)

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 (ATCA) 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 24 microns, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.

Reynolds, Mark; Loi, S. T.; Murphy, T.; Miller, J. M.; Maitra, D.; Gultekin, K.; Gehrels, N.; Kennea, J. A.; Siegel, M. H.; Gelbord, J.; Kuin, P.; Moss, V.; Reeves, S.; Robbins, W. J.; Gaensler, B. M.; Reis, R. C.; Petre, R.

2013-04-01

228

Far-ultraviolet Cooling Features Of A Mixed-Morphology Supernova Remnant  

NASA Astrophysics Data System (ADS)

Mixed-Morphology Supernova Remnants (MM SNRs) are well known for their unusual center-filled X-ray morphology. Two models have been explained such property, employing different distributions of cold-and-dense gas components around the supernova. To investigate the cooling feature of MM SNRs, we observed the Antlia SNR, a large MM SNR ( 24 in diameter), in far-ultraviolet domain with Spectroscopy of Plasma Evolution from Astrophysical Radiation (SPEAR, aka FIMS). We detected C III ?977 and C IV ??1548,1551 emission lines, which might be generated as the hot gas of the remnant cool down interacting with the ambient cold gas. The C IV emission line map shows a clumpy distribution, and the temperature profile---inferred from the line ratio of C III and C IV---is increasing near the edge of the remnant. These results are more compatible with the thermal evaporation model than the thermal conduction model, which predicts the edge-concentrated C IV feature and the decreasing temperature profile near the edge of the remnant.

Shinn, Jong-Ho; Min, K.; Sankrit, R.; Ryu, K.; Kim, I.; Han, W.; Nam, U.; Park, J.; Edelstein, J.; Korpela, E.; FIMS Team at KAIST; FIMS Team at KASI; SPEAR Team at SSL

2007-05-01

229

Simulations of Supernova Remnants in Diffuse Media. III. The Population of Buoyant Remnants above the Milky Way's Disk  

NASA Astrophysics Data System (ADS)

We model SNRs at a variety heights above the disk with a detailed numerical simulation that includes nonequilibrium ionization and recombination and follows the remnants' evolution until their hot bubbles have cooled. We analytically calculate the bubbles' buoyant acceleration and frictional drag. From the simulation results, combined with the rates for isolated supernova explosions above a height of 130 pc, we estimate the time and space average O+5, N+4, and C+3 column densities and emission intensities, 1/4 keV soft X-ray surface brightness, area coverage, and volume occupation due to the population of isolated SNRs above the Galaxy's H I layer. Irrespective of assumed supernova explosion energy, ambient nonthermal pressure, or frictional drag coefficient used in the calculations, the predicted O+5 column density as a function of height matches the observed distribution between 130 and 2000 pc. The O VI resonance line emission (??1032, 1038) contributes significantly to the average observed intensity. Assuming our modest supernova explosion rate, the population of isolated extraplanar SNRs can explain 80% of the observed 1/4 keV surface brightness attributed to the extraplanar gas beyond the H I layer in the southern hemisphere. Within the range of uncertainty in the SN rate, such SNRs can explain all of this observed emission (40010-6 counts s-1 arcmin-2). Thus, extraplanar SNRs could be the most important sources of hot gas between the Local Bubble and z~2000 pc in the relatively quiescent southern hemisphere. These results stand whether the remnants are assumed to be buoyant or not. The population of old extraplanar SNRs should cover most, but not all of the high-latitude sky, thus explaining the mottled appearance of the soft X-ray maps (outside of superbubbles). Bright young extraplanar SNRs should cover less than 1% of the high-latitude sky. Perhaps the l=247, b=-64 crescent in the 1/4 keV X-ray maps could be such a remnant.

Shelton, R. L.

2006-02-01

230

Hard X-ray Emission and Efficient Particle Acceleration by Supernova Remnants  

NASA Astrophysics Data System (ADS)

I discuss the non-thermal X-ray emission from young supernova remnants. Over the last decade it has become clear from both X-ray and ?-ray observations that young supernovae accelerate particles up to 100 TeV. In soft X-rays the accelerated >10 TeV electrons produce synchrotron radiation, coming from narrow filaments located at the shock fronts. The width of these filaments shows that the magnetic fields are relatively high, thus providing evidence for magnetic field amplification. The synchrotron radiation of several remnants is known to extend into the hard X-ray regime. In particular Cas A, has a spectrum that appears as a power law up to almost 100 TeV. This is very surprising, as a steepening is expected going from the soft to the hard X-ray band. The spectrum is likely a result of many superimposed individual spectra, each steepening at different energies. This implies considerable spatial variation in hard X-rays, an obvious target for Simbol-X. The variations will be important to infer local shock acceleration properties, but also magnetic field fluctuations may cause spatial and temporal variations. Finally, I draw the attention to super bubbles and supernovae as sources of cosmic rays. As such they may be sources of hard X-ray emission. In particular, supernovae exploding inside the dense red supergiants winds of their progenitors ares promising candidates for hard X-ray emission.

Vink, Jacco

2009-05-01

231

The Supernova Remnant 3C 400.2: Kinematics of its Ionized Gas and Theoretical Results  

NASA Astrophysics Data System (ADS)

3C 400.2 is a supernova remnant (SNR) with a complex morphology consisting of two overlapped shells of different diameters: a large shell at the southeast and a small shell at the northwest. High-resolution radio-continuum observations carried out by Dubner et al. (1994) suggested that this complex morphology could be due to the interaction of two SNRs. However, this view has been challenged by recent studies of the H I distribution around this SNR (Giacani et al. 1998) and by the confrontation of theoretical evolutionary models with the morphology at H alpha of this remnant (Velazquez et al. 2001). These recent results suggest that the double shell structure is produced by a single supernova explosion initially expanding into a dense medium encountering a lower density medium and producing a blowout. In this work we present the results of H alpha Fabry-Perot observations obtained with the PUMA equipment at the 2.1 m telescope of the Observatorio Astronmico Nacional at San Pedro Mrtir, B. C., Mxico. The kinematic results obtained can allow us to distinguish between those possibilities: two supernova explosions or one supernova explosion undergoing a blowout due to a density gradient.

Ambrocio-Cruz, P.; de La Fuente, E.; Rosado, M.; Velzquez, P. F.

2003-01-01

232

Which pulsars should drive plerions?  

NASA Astrophysics Data System (ADS)

The postulated association between supernova remnant morphology and supernova type (Type Ia--shell, Type II--plerion or composite), combined with observationally derived birthrates of Galactic supernovae (van den Bergh et al., 1987, Astroys. J., 323, 44), implies that 60 to 85% of Galactic supernova remnants (SNRs) should be plerions or composites. In fact, of the approximately 150 Galactic SNRs discovered to date, approximately 85% are shells. Old remnants are certainly too dissipated to confine the relativistic wind from a central pulsar, but young condensed SNRs should host plerions visible from any viewing geometry. One explanation for the paucity of plerions is that neutron stars are born with a weak magnetic field, only switching on as pulsars after 105 years (when the SNR has largely dissipated) following a period of thermoelectric field growth (Blandford et al., 1983, Mon. Not. R. Astron. Soc., 204, 1025). Another possibility is that all Type II supernovae contain a pulsar surrounded by a plerion and a shell of ejecta. Whether we see the plerion or shell depends on which component has the highest surface brighteness. Supernova remnants whose shell and plerionic components evolve independently have been modeled by Bhattacharya (1990, J. Astrophys. Astron., 11, 125). Three ingredients enter the model: (i) the plerion's synchrotron luminosity evolves due to adiabatic expansion of the nebula (Pacini and Salvati, 1973, Astrophys. J., 186, 249); (ii) shell emission is governed by turbulent amplification of the magnetic field and Fermi acceleration of particles (Gull 1973, Mon. Not. R. Astron. Soc., 161, 47); and (iii) expansion of the plerion and shell are driven by the supernova blast rather than the relativistic wind from the pulsar, with the plerion occupying all the volume within the expanding shell. The model only reproduces a plerionic morphology under the following restricted conditions: the initial period and magnetic field of the pulsar are Crab-like, and the supernova explosion occurs in a low-density ambient medium or the supernova event itself is less energetic than normal. pulsar deposits most of its energy at early epochs when the nebular is still small and adiabatic losses are most severe, thereby depleting the energy content of the plerion at later (epochs. &Since the range of favorable conditions is so limited, the model provides a natural explanation for why so few plerions are observed. The puzzling properties of the remnant MSH 15-52 can also be understood in this context.

Melatos, A.

1994-04-01

233

3-D Model of Broadband Emission from Supernova Remnants Undergoing Non-linear Diffusive Shock Acceleration  

SciTech Connect

We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occurring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When applied to a specific SNR, our model will predict cosmic-ray spectra and multi-wavelength morphology in projected images for instruments with varying spatial and spectral resolutions. We show examples of these spectra and images and emphasize the importance of measurements in the hard X-ray, GeV, and TeV gamma-ray bands for investigating key ingredients in the acceleration mechanism, and for deducing whether or not TeV emission is produced by IC from electrons or pion-decay from protons.

Lee, Shiu-Hang; Kamae, Tuneyoshi; Ellison, Donald C.

2008-07-02

234

THE CHANDRA ACIS SURVEY OF M33: X-RAY, OPTICAL, AND RADIO PROPERTIES OF THE SUPERNOVA REMNANTS  

SciTech Connect

M33 contains a large number of emission nebulae identified as supernova remnants (SNRs) based on the high [S II]:H{alpha} ratios characteristic of shocked gas. Using Chandra data from the ChASeM33 survey with a 0.35-2 keV sensitivity of {approx}2 x 10{sup 34} erg s{sup -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 {approx}4 x 10{sup 35} erg s{sup -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.; Ghavamian, Parviz [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Blair, William P.; Kuntz, Kip D. [The Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Winkler, P. Frank; McNeil, Emily K. [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Becker, Robert H. [Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616 (United States); Gaetz, Terrance J.; Kirshner, Robert P.; Plucinsky, Paul P.; Tuellmann, Ralph [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Helfand, David J.; Saul, Destry [Columbia Astrophysics Laboratory, 550 W. 120th Street, New York, NY 10027 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Pannuti, Thomas G. [Department of Earth and Space Sciences, Space Science Center, 235 Martindale Drive, Morehead State University, Morehead, KY 40351 (United States); Williams, Benjamin [Astronomy Department, University of Washington, Seattle, WA 98195 (United States)], E-mail: long@stsci.edu, E-mail: wpb@pha.jhu.edu, E-mail: winkler@middlebury.edu

2010-04-01

235

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

236

An atlas of supernova remnant candidates in Messier 31  

NASA Astrophysics Data System (ADS)

Narrow-band CCD imagery in H-alpha and forbidden SII of a large fraction of the spiral arms in the Northeast half of Messier 31 has been used to isolate a sample of 52 'forbidden-line' SNR candidates for which the integrated ratio forbidden SII:H-alpha is greater than 0.5. An atlas of images in these emission lines, red optical continuum, and 1465 MHz radio continuum is presented, together with the tabulated integral properties of these sources. Assessing the completeness of the sample yields a crude estimate of the massive supernova rate (due to stars more massive than 7 solar masses) of 1 in 80 yr. The range of measured luminosities in both H-alpha and radio continuum is fully consistent with those found for 'forbidden-line' SNR in Messier 33, the LMC, and the Galaxy. With the inclusion of our candidates the number of extragalactic SNRs (with well-known distances) now exceeds the number of known galactic SNRs.

Braun, R.; Walterbos, R. A. M.

1993-04-01

237

The resolved structure of the extragalactic supernova remnant SNR 4449-1  

NASA Astrophysics Data System (ADS)

We present very long baseline interferometry (VLBI) observations of the milliarcsecond-scale radio structure of the supernova remnant SNR 4449-1 in the galaxy NGC 4449. This young and superluminous remnant was observed at 1.6 GHz (? = 18 cm) with the European VLBI Network. The observations confirm earlier identifications of this object with a supernova remnant (SNR) while revealing a somewhat different morphology compared with the structure reported by Bietenholz et al. from VLBI observations at 1.4 GHz. This difference is discussed here in the context of structural sensitivity of both observations. The 1.6 GHz image yields accurate estimates of the size (0.0422 arcsec 0.0285 arcsec and 0.8 pc 0.5 pc) and age (55 yr) of SNR 4449-1. With a total flux of 6.1 0.6 mJy measured in the VLBI image, the historical light curve of the source can be well represented by a power-law decay with a power index of -1.19 0.07. The SNR exhibits a decline rate of the radio emission of 2.2 0.1 per cent yr-1 and a radio luminosity of 1.74 1035 erg s-1.

Mezcua, M.; Lobanov, A. P.; Mart-Vidal, I.

2013-10-01

238

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

239

Spitzer observations of the N157B supernova remnant and its surroundings  

NASA Astrophysics Data System (ADS)

Aims: We study the LMC interstellar medium in the field of the nebula N157B, which contains a supernova remnant, an OB association, ionized gas, and high-density dusty filaments in close proximity. We investigate the relative importance of shock excitation by the SNR and photo-ionization by the OB stars, as well as possible interactions between the supernova remnant and its environment. Methods: We apply multiwavelength mapping and photometry, along with spatially resolved infrared spectroscopy, to identifying the nature of the ISM using new infrared data from the Spitzer space observatory and X-ray, optical, and radio data from the literature. Results: The N157B SNR has no infrared counterpart. Infrared emission from the region is dominated by the compact blister-type HII region associated with 2MASS J05375027-6911071 and excited by an O8-O9 star. This object is part of an extended infrared emission region that is associated with a molecular cloud. We find only weak emission from the shock-indicator [FeII], and both the excitation and the heating of the extended cloud are dominated by photo-ionization by the early O stars of LH 99. Conclusions: Any possible impact by the expanding SNR does not now affect the extended cloud of molecules and dust, despite the apparent overlap of SNR X-ray emission with infrared and H? emission from the cloud. This implies that the supernova progenitor cannot have been more massive than about 25 M?.

Micelotta, E. R.; Brandl, B. R.; Israel, F. P.

2009-06-01

240

Two populations of X-ray pulsars produced by two types of supernova  

NASA Astrophysics Data System (ADS)

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.

Knigge, Christian; Coe, Malcolm J.; Podsiadlowski, Philipp

2011-11-01

241

Rayleigh-Taylor instabilities in Type Ia supernova remnants undergoing cosmic ray particle acceleration - low adiabatic index solutions  

NASA Astrophysics Data System (ADS)

This study investigates the evolution of Rayleigh-Taylor (R-T) instabilities in Type Ia supernova remnants that are associated with a low adiabatic index ?, where ? < 5/3, which reflects the expected change in the supernova shock structure as a result of cosmic ray particle acceleration. Extreme cases, such as the case with the maximum compression ratio that corresponds to ?= 1.1, are examined. As ? decreases, the shock compression ratio rises, and an increasingly narrow intershock region with a more pronounced initial mixture of R-T unstable gas is produced. Consequently, the remnant outline may be perturbed by small-amplitude, small-wavelength bumps. However, as the instability decays over time, the extent of convective mixing in terms of the ratio of the radius of the R-T fingers to the blast wave does not strongly depend on the value of ? for ?? 1.2. As a result of the age of the remnant, the unstable gas cannot extend sufficiently far to form metal-enriched filaments of ejecta material close to the periphery of Tycho's supernova remnant. The consistency of the dynamic properties of Tycho's remnant with the adiabatic model ?= 5/3 reveals that the injection of cosmic rays is too weak to alter the shock structure. Even with very efficient acceleration of cosmic rays at the shock, significantly enhanced mixing is not expected in Type Ia supernova remnants.

Wang, Chih-Yueh

2011-07-01

242

Dense, Fe-rich Ejecta in Supernova Remnants DEM L238 and DEM L249: A New Class of Type Ia Supernova?  

Microsoft Academic Search

We present observations of two LMC supernova remnants (SNRs), DEM L238 and\\u000aDEM L249, with the Chandra and XMM-Newton X-ray satellites. Bright central\\u000aemission, surrounded by a faint shell, is present in both remnants. The central\\u000aemission has an entirely thermal spectrum dominated by strong Fe L-shell lines,\\u000awith the deduced Fe abundance in excess of solar and not consistent

Kazimierz J. Borkowski; Sean P. Hendrick; Stephen P. Reynolds

2006-01-01

243

Cosmic-Ray Electron Evolution in the Supernova Remnant RX J1713.7-3946  

NASA Astrophysics Data System (ADS)

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 ~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 ~ 16 ?G, comparable to shock-compressed fields found in the bulk of the remnant.

Finke, Justin D.; Dermer, Charles D.

2012-05-01

244

EXPANSION OF THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3  

SciTech Connect

We present a measurement of the expansion and brightening of G1.9 + 0.3, the youngest Galactic supernova remnant (SNR), comparing Chandra X-ray images obtained in 2007 and 2009. A simple uniform-expansion model describes the data well, giving an expansion rate of 0.642% {+-} 0.049% yr{sup -1} and a flux increase of 1.7% {+-} 1.0% yr{sup -1}. Without deceleration, the remnant age would then be 156 {+-} 11 yr, consistent with earlier results. Since deceleration must have occurred, this age is an upper limit; we estimate an age of about 110 yr or an explosion date of about 1900. The flux increase is comparable to reported increases at radio wavelengths. G1.9+0.3 is the only Galactic SNR increasing in flux, with implications for the physics of electron acceleration in shock waves.

Carlton, Ashley K. [Department of Physics, Wake Forest University, Winston-Salem, NC 27109 (United States); Borkowski, Kazimierz J.; Reynolds, Stephen P. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Hwang, Una; Petre, Robert [NASA/GSFC, Code 660, Greenbelt, MD 20771 (United States); Green, David A. [Cavendish Laboratory, 19 J.J. Thomson Ave., Cambridge CB3 0HE (United Kingdom); Krishnamurthy, Kalyani; Willett, Rebecca, E-mail: carlak7@wfu.edu [Electrical and Computer Engineering, Duke University, Durham, NC 27708 (United States)

2011-08-10

245

X-ray characteristics of the Lupus Loop and SN 1006 supernova remnants  

SciTech Connect

The spatial extent of the Lupus Loop and spectra for the Lupus Loop and SN1006 supernova remnants have been determined with a rocket-borne payload. The Lupus Loop is an extended source of soft X-rays (approx. 300' diam) that shows a correlation between its brightest x-ray and radio-emission regions. Its spectrum is characterized by a temperature of 350 eV. Thus, the Lupus Loop appears similar to Vela X and Cygnus Loop, although much weaker. Emission from SN1006 is spatially unresolved and exhibits a harder spectrum than that of the Lupus Loop. All spectral data (0.2 to 10 keV) from our observation and previous observations are satisfactorily fit with a power law (index = 2.15). This spectral dependence suggests the possibility that a rotating neutron star is the underlying source of the radiated energy although such an interpretation appears inconsistent with the remnant's morphology.

Toor, A.

1980-01-01

246

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

247

AN X-RAY INVESTIGATION OF THREE SUPERNOVA REMNANTS IN THE LARGE MAGELLANIC CLOUD  

SciTech Connect

We have investigated three supernova remnants (SNRs) in the LMC using multi-wavelength data. These SNRs are generally fainter than the known sample (see Section 4) and may represent a previously missed population. One of our SNRs is the second LMC remnant analyzed which is larger than any Galactic remnant for which a definite size has been established. The analysis of such a large remnant contributes to the understanding of the population of highly evolved SNRs. We have obtained X-ray images and spectra of three of these recently identified SNRs using the XMM-Newton observatory. These data, in conjunction with pre-existing optical emission-line images and spectra, were used to determine the physical conditions of the optical- and X-ray-emitting gas in the SNRs. We have compared the morphologies of the SNRs in the different wavebands. The physical properties of the warm ionized shell were determined from the H{alpha} surface brightness and the SNR expansion velocity. The X-ray spectra were fit with a thermal plasma model and the physical conditions of the hot gas were derived from the model fits. Finally, we have compared our observations with simulations of SNR evolution.

Klimek, Matthew D.; Points, S. D.; Smith, R. C. [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Shelton, R. L. [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States); Williams, R., E-mail: klimek@physics.rutgers.ed, E-mail: spoints@ctio.noao.ed, E-mail: csmith@ctio.noao.ed, E-mail: rls@physast.uga.ed, E-mail: rosanina@ccssc.or [Columbus State University, Coca-Cola Space Science Center, 701 Front Avenue, Columbus, GA, 31901 (United States)

2010-12-20

248

NONTHERMAL PROPERTIES OF SUPERNOVA REMNANT G1.9+0.3  

SciTech Connect

The properties of the-presumably-youngest Galactic supernova remnant (SNR) G1.9+0.3 are investigated within the framework of nonlinear kinetic theory of cosmic ray acceleration in SNRs. The observed angular size and expansion speed as well as the radio and X-ray emission measurements are used to determine relevant physical parameters of this SNR. Under the assumption that SNR G1.9+0.3 is the result of a Type Ia supernova near the Galactic center (at the distance d = 8.5 kpc), the nonthermal properties are calculated. In particular, the expected TeV gamma-ray spectral energy density is predicted to be as low as {epsilon}{sub {gamma}} F{sub {gamma} {approx}} 5 x 10{sup -15} erg cm{sup -2} s{sup -1}, strongly dependent (F{sub {gamma} {proportional_to}} d {sup -11}) upon the source distance d.

Ksenofontov, L. T.; Berezhko, E. G. [Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation); Voelk, H. J., E-mail: ksenofon@ikfia.ysn.r [Max-Planck-Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)

2010-05-10

249

Observations of the supernova remnants Cas-A and Tycho with the HEGRA stereoscopic IACT system  

NASA Astrophysics Data System (ADS)

Recently, young supernova remnants (SNR) from type Ia Supernovae (SNe) have become targets of interest for TeV gamma-ray astronomy. This prompted the HEGRA collaboration to extensively observe Tycho's SNR in 1997 and 1998 with its stereoscopic IACT system. The HEGRA IACT system was also used to observe the young SNR Cas-A. Although considered to be the result of a SN type Ib, the detected strong nonthermal X-ray emission makes this SNR a promising candidate for TeV gamma-ray emission. Given the spatial resolution of the system, both sources are still nearly pointlike. Therefore, the data samples yield an emission sensitivity close to a few percent of the Crab flux. The Cas-A observations reveal evidence for a TeV signal.

Puehlhofer, Gerd

1999-08-01

250

Exploring the ?-ray emissivity of young supernova remnants - I. Hadronic emission  

NASA Astrophysics Data System (ADS)

Using a simplified model for the hadronic emission from young supernova remnants (SNRs), we derive an expression to calculate the hadronic luminosity with time, depending on the supernova (SN) ejecta density profile and the density structure of the surrounding medium. Our analysis shows that the hadronic emission will decrease with time for core-collapse SNe expanding in the winds of their progenitor stars, but increase with time for SNe expanding into a constant density medium, typical of Type Ia SNe. Using our expressions, we can compute the time-dependent hadronic flux from some well-known young SNe and SNRs with time, and where applicable reproduce previous results in the appropriate parameter regime. Using our calculations, we also emphasize the exciting possibility that SN 1987A may become a visible ?-ray source in the next decade.

Dwarkadas, V. V.

2013-10-01

251

Constraining comsic ray acceleration in supernova remnants through radio and X-ray observations  

NASA Astrophysics Data System (ADS)

It is now accepted that supernova remnants may provide enough energy to accelerate the particles which are then detected as cosmic rays on the earth, at least up to the "knee" of the spectrum around 1000 TeV. Radio and X-ray emission observed in accelerating SNR shells both comes from the same electron population, and samples different bands in its energy spectrum. In this talk, I present a few observational cases in which the multi-wavelength radio/X-ray approach have provided important information about the acceleration processes occurring at SNR shocks.

Bocchino, Fabrizio

2012-07-01

252

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

253

Observations of X-rays and Thermal Dust Emission from the Supernova Remnant Kes 75  

Microsoft Academic Search

We present Spitzer Space Telescope and Chandra X-ray Observatory observations\\u000aof the composite Galactic supernova remnant Kes 75 (G29.7-0.3). We use the\\u000adetected flux at 24 microns and hot gas parameters from fitting spectra from\\u000anew, deep X-ray observations to constrain models of dust emission, obtaining a\\u000adust-to-gas mass ratio M_dust\\/M_gas ~0.001. We find that a two-component\\u000athermal model, nominally

Timothy D. Morton; Patrick Slane; Kazimierz J. Borkowski; Stephen P. Reynolds; David J. Helfand; B. M. Gaensler; John P. Hughes

2007-01-01

254

X-ray spectra of young type I supernova remnants: Exploded white dwarfs  

SciTech Connect

We argue that the X-ray spectra of young Type I supernova remnants can be understood consistently in terms of thermal emission mainly from a reverse shock into initially uniform density ejecta. The inferred mass of ejecta is then consistent with 1.4 M/sub sun/ in SN 1006, Tycho, and Kepler. A substantial mass of iron, perhaps approx.0.8 M/sub sun/, may be present provided that the ejecta are chemically inhomogeneous, with iron confined to inner layers of ejecta. The marked difference between the X-ray spectra of SN 1006 and Tycho is explained by the lower interstellar density around SN 1006.

Hamilton, A.J.S.; Sarazin, C.L.; Szymkowiak, A.E.; Vartanian, M.H.

1985-10-01

255

Limits on the Number of Galactic Young Supernova Remnants Emitting in the Decay Lines of 44Ti  

NASA Astrophysics Data System (ADS)

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 44Ti. Specifically, we consider the distribution of the supernova progenitors, the supernova rate in the Galaxy, the ratios of supernova types, the Galactic production of 44Ti, and the 44Ti 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^{+2.4}_{-2.0} remnants detectable to a survey with a 44Ti decay line flux limit of 10-5 photons cm-2 s-1, with a probability of detecting a single remnant of 2.7^{+10.0}_{-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 44Ti 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 44Ti, 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 44Ti decay flux of 10-7 photons cm-2 s-1.

Dufour, Franois; Kaspi, Victoria M.

2013-09-01

256

X-ray Spectral Analysis of Dim Type Ia Supernova Remnant Candidates in the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We report on the statistical analyses of three morphologically asymmetric low-count supernova remnants, designated IKT 5, IKT 25, and DEM S 128 in the Small Magellanic Cloud (SMC). These remnants have been previously identified as Type Ia candidates based on the presumed overabundance of iron in their XMM CCD spectra. We have used archived Chandra data to perform spectral analyses on these three remnants. Their tentative Type Ia designation and morphological asymmetry is in contrast to more recent findings that soft x-ray morphology is generally more symmetric in Type Ia remnants in the Large Magellanic Cloud and Milky Way. We combine the Chandra data with Spitzer data to show that the morphology is affected by complicated environmental interactions with these remnants. Moreover, by performing a maximum-likelihood analysis fitting technique on the soft X-ray spectra of these remnants, we find that these remnants are dominated by surrounding ISM emission, as opposed to being iron ejecta-dominated, as expected for younger Type Ia supernova remnants.

Roper, Quentin; McEntaffer, R.; DeRoo, C.

2012-01-01

257

Fermi-Lat Discovery of GeV Gamma-Ray Emission from the Young Supernova Remnant Cassiopeia A  

Microsoft Academic Search

We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant (SNR) with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2sigma above 500 MeV at a location that is consistent with the position of the remnant

A. A. Abdo; M. Ackermann; M. Ajello; A. Allafort; 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; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; R. Buehler; T. H. Burnett; G. Busetto; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; . elik; E. Charles; S. Chaty; A. Chekhtman; C. C. Cheung; J. Chiang; A. N. Cillis; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Corbel; F. de Palma; S. W. Digel; M. Dormody; E. do Couto e. Silva; P. S. Drell; R. Dubois; D. Dumora; Y. Edmonds; C. Farnier; C. Favuzzi; S. J. Fegan; E. C. Ferrara; W. B. Focke; P. Fortin; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; G. Giavitto; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; E. Hays; A. K. Harding; M. Hayashida; D. Horan; R. E. Hughes; M. S. Jackson; A. S. Johnson; T. J. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; M. Kerr; J. Kndlseder; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; T. Nakamori; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; A. Okumura; N. Omodei; E. Orlando; J. F. Ormes; D. Paneque; J. H. Panetta; V. Pelassa; M. Pepe; M. Pesce-Rollins; F. Piron; M. Pohl; T. A. Porter; S. Rain; R. Rando; A. Reimer; O. Reimer; T. Reposeur; S. Ritz; A. Y. Rodriguez; R. W. Romani; M. Roth; H. F.-W. Sadrozinski; A. Sander; P. M. Saz Parkinson; J. D. Scargle; C. Sgr; E. J. Siskind; D. A. Smith; P. D. Smith; P. Spinelli; M. S. Strickman; D. J. Suson; H. Tajima; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; S. E. Thorsett; L. Tibaldo; O. Tibolla; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; A. Van Etten; V. Vasileiou; C. Venter; N. Vilchez; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; R. Yamazaki; T. Ylinen; M. Ziegler

2010-01-01

258

The morphology and dynamics of a multi-lobed supernova remnant in the LMC (DEM 34a, N11L)  

Microsoft Academic Search

Photon-counting imagery of the 1624 pc supernova remnant, DEM 34a, has revealed a secondary lobe projecting from the bright ring of emission line filaments. Spatially resolved, long-slit echelle spectra of the Halpha and [N II] emission lines show that complex motions are occurring within this remnant. Multiple lobes expanding with velocities of up to 350 km s-1 are present. The

John Meaburn

1987-01-01

259

The End of Amnesia: Measuring the Metallicities of Type Ia SN Progenitors with Manganese Lines in Supernova Remnants  

NASA Astrophysics Data System (ADS)

The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of the Tycho Supernova Remnant. The fluxes of the Mn and Cr K? lines in the X-ray spectra of Tycho observed by the Suzaku satellite suggests a progenitors of supersolar metallicity.

Badenes, Carles; Bravo, Eduardo; Hughes, John P.

2009-05-01

260

CAVITY OF MOLECULAR GAS ASSOCIATED WITH SUPERNOVA REMNANT 3C 397  

SciTech Connect

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 the remnant is well confined in a cavity of molecular gas and embedded at the edge of a molecular cloud (MC) at the local standard of rest systemic velocity of {approx}32 km s{sup -1}. The cloud has a column density gradient increasing from southeast to northwest, perpendicular to the Galactic plane, in agreement with the elongation direction of the remnant. This systemic velocity places the cloud and SNR 3C 397 at a kinematic distance of {approx}10.3 kpc. The derived mean molecular density ({approx}10-30 cm{sup -3}) explains the high volume emission measure of the X-ray emitting gas. A {sup 12}CO line broadening of the {approx}32 km s{sup -1} component is detected at the westmost boundary of the remnant, which provides direct evidence of the SNR-MC interaction and suggests multi-component gas there with dense ({approx}10{sup 4} cm{sup -3}) molecular clumps. We confirm the previous detection of an MC at {approx}38 km s{sup -1} to the west and south of the SNR and argue, based on H I self-absorption, that the cloud is located in the foreground of the remnant. A list of Galactic SNRs presently known and suggested to be in physical contact with environmental MCs is appended in this paper.

Jiang Bing; Chen Yang; Wang Junzhi; Zhou Xin [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Su Yang [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Safi-Harb, Samar [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada); DeLaney, Tracey [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139 (United States)

2010-04-01

261

RADIOACTIVE SCANDIUM IN THE YOUNGEST GALACTIC SUPERNOVA REMNANT G1.9+0.3  

SciTech Connect

We report the discovery of thermal X-ray emission from the youngest Galactic supernova remnant G1.9+0.3, from a 237 ks Chandra observation. We detect strong K{alpha} lines of Si, S, Ar, Ca, and Fe. In addition, we detect a 4.1 keV line with 99.971% confidence which we attribute to {sup 44}Sc, produced by electron capture from {sup 44}Ti. Combining the data with our earlier Chandra observation allows us to detect the line in two regions independently. For a remnant age of 100 yr, our measured total line strength indicates synthesis of (1-7) x 10{sup -5} M {sub sun} of {sup 44}Ti, in the range predicted for both Type Ia and core-collapse supernovae (SNe), but somewhat smaller than the 2 x 10{sup -4} M {sub sun} reported for Cas A. The line spectrum indicates supersolar abundances. The Fe emission has a width of about 28,000 km s{sup -1}, consistent with an age of {approx}100 yr and with the inferred mean shock velocity of 14,000 km s{sup -1} deduced assuming a distance of 8.5 kpc. Most thermal emission comes from regions of lower X-ray but higher radio surface brightness. Deeper observations should allow more detailed spatial mapping of {sup 44}Sc, with significant implications for models of nucleosynthesis in Type Ia SNe.

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

2010-12-01

262

TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD  

SciTech Connect

The historical supernova remnant (SNR) Tycho SN 1572 originates from the explosion of a normal Type Ia supernova that is believed to have originated from a carbon-oxygen white dwarf in a binary system. We analyze the 21 cm continuum, H I, and {sup 12}CO-line data from the Canadian Galactic Plane Survey in the direction of SN 1572 and the surrounding region. We construct H I absorption spectra to SN 1572 and three nearby compact sources. We conclude that SN 1572 has no molecular cloud interaction, which argues against previous claims that a molecular cloud is interacting with the SNR. This new result does not support a recent claim that dust, newly detected by AKARI, originates from such an SNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5-3.0 kpc based on a nonlinear rotational curve model. Very high energy {gamma}-ray emission from the remnant has been detected by the VERITAS telescope, so our result shows that its origin should not be an SNR-cloud interaction. Both radio and X-ray observations support that SN 1572 is an isolated Type Ia SNR.

Tian, W. W. [National Astronomical Observatories, CAS, Beijing 100012 (China); Leahy, D. A., E-mail: tww@bao.ac.cn [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada)

2011-03-10

263

Typing Supernova Remnants Using Symmetry Analysis of Warm Dust Emission Observed with Spitzer  

NASA Astrophysics Data System (ADS)

Observational determination of the explosion type of a supernova remnant (SNR) is challenging: SNRs are hundreds to thousands of years old, whereas supernovae are typed days after explosion based on spectral properties. Previous results (Lopez et. al. 2011) have shown that young core-collapse (CC) and Type Ia SNRs found in the Galaxy and Large Magellanic Cloud can be separated statistically using a power-ratio (multipole expansion) analysis of the morphology of their thermal X-ray emission. Here, we extend this technique to the infrared to see whether SNRs can be similarly typed at wavelengths probing the SNR dust environment. We analyze Spitzer Space Telescope 24-micron IR images of the previously used X-ray sample. We find that the two populations separate according to their IR morphologies: the Type Ia SNRs are statistically more mirror-symmetric than the CC SNRs. Our results suggest that the interstellar medium around Type Ia SNRs is more spatially homogenous than that of CC SNRs, because the IR emission traces the warm dust in the environment of the SNRs. Broadly, our work indicates that the IR emission retains information of the explosive origins of the remnant and that SNRs can be typed based on the degree of IR symmetry.

Peters, Charee L.; Lopez, L. A.; Figueroa-Feliciano, E.; Ramirez, E.; Stassun, K.

2013-01-01

264

How precisely can neutrino emission from supernova remnants be constrained by gamma ray observations?  

SciTech Connect

We propose a conceptually and computationally simple method to evaluate the neutrinos emitted by supernova remnants using the observed {gamma} ray spectrum. The proposed method does not require any preliminary parametrization of the gamma ray flux; the gamma ray data can be used as an input. In this way, we are able to propagate easily the observational errors and to understand how well the neutrino flux and the signal in neutrino telescopes can be constrained by {gamma} ray data. We discuss the various possible sources of theoretical and systematical uncertainties (e.g., hadronic modeling, neutrino oscillation parameters, etc.), obtaining an estimate of the accuracy of our calculation. Furthermore, we apply our approach to the supernova remnant RX J1713.7-3946, showing that neutrino emission is very well constrained by the H.E.S.S. {gamma} ray data: indeed, the accuracy of our prediction is limited by theoretical uncertainties. The observation of neutrinos from RX J1713.7-3946 seems possible with an exposure of the order of few km{sup 2}xyear, provided that the detection threshold in future neutrino telescopes will be not higher than about 1 TeV.

Villante, F. L. [Universita dell'Aquila, Dipartimento di Fisica, L'Aquila (Italy); INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Vissani, F. [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy)

2008-11-15

265

GAMMA-RAY EMISSION OF ACCELERATED PARTICLES ESCAPING A SUPERNOVA REMNANT IN A MOLECULAR CLOUD  

SciTech Connect

We present a model of gamma-ray emission from core-collapse supernovae (SNe) originating from the explosions of massive young stars. The fast forward shock of the supernova remnant (SNR) can accelerate particles by diffusive shock acceleration (DSA) in a cavern blown by a strong, pre-SN stellar wind. As a fundamental part of nonlinear DSA, some fraction of the accelerated particles escape the shock and interact with a surrounding massive dense shell producing hard photon emission. To calculate this emission, we have developed a new Monte Carlo technique for propagating the cosmic rays (CRs) produced by the forward shock of the SNR, into the dense, external material. This technique is incorporated in a hydrodynamic model of an evolving SNR which includes the nonlinear feedback of CRs on the SNR evolution, the production of escaping CRs along with those that remain trapped within the remnant, and the broadband emission of radiation from trapped and escaping CRs. While our combined CR-hydro-escape model is quite general and applies to both core collapse and thermonuclear SNe, the parameters we choose for our discussion here are more typical of SNRs from very massive stars whose emission spectra differ somewhat from those produced by lower mass progenitors directly interacting with a molecular cloud.

Ellison, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States); Bykov, Andrei M., E-mail: don_ellison@ncsu.edu, E-mail: byk@astro.ioffe.ru [Ioffe Institute for Physics and Technology, 194021 St. Petersburg (Russian Federation)

2011-04-20

266

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

267

The Double Pulsar: Evidence for Neutron Star Formation without an Iron Core-collapse Supernova  

NASA Astrophysics Data System (ADS)

The double pulsar system PSR J07373039A/B is a double neutron star binary, with a 2.4 hr orbital period, which has allowed measurement of relativistic orbital perturbations to high precision. The low mass of the second-formed neutron star, as well as the low system eccentricity and proper motion, point to a different evolutionary scenario compared to most other known double neutron star systems. We describe analysis of the pulse profile shape over 6 years of observations and present the resulting constraints on the system geometry. We find the recycled pulsar in this system, PSR J07373039A, to be a near-orthogonal rotator with an average separation between its spin and magnetic axes of 90 11 5. Furthermore, we find a mean 95% upper limit on the misalignment between its spin and orbital angular momentum axes of 3.2, assuming that the observed emission comes from both magnetic poles. This tight constraint lends credence to the idea that the supernova that formed the second pulsar was relatively symmetric, possibly involving electron capture onto an O-Ne-Mg core.

Ferdman, R. D.; Stairs, I. H.; Kramer, M.; Breton, R. P.; McLaughlin, M. A.; Freire, P. C. C.; Possenti, A.; Stappers, B. W.; Kaspi, V. M.; Manchester, R. N.; Lyne, A. G.

2013-04-01

268

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

269

Nonthermal radiation from supernova remnants in the adiabatic stage of evolution  

SciTech Connect

We develop a physically self-consistent model for nonthermal radiation from supernova remnants in the adiabatic blast-wave (Sedov) phase of evolution, assuming relativistic electrons are accelerated in the shock to an energy density proportional to the postshock pressure, and that the magnetic field is either compressed ambient field or turbulently amplified. We have compared the resulting synchrotron profiles with observations of Tycho's remnant and find the amplified magnetic field model gives an adequate fit if there is a small radially ordered component of the magnetic field at the shock wave. The model predicts that surface brightness of Tycho declines as (diameter)/sup -4.4/ and that the flux declines by 0.25% per year. We explain the featureless power-law X-ray spectrum of the SN 1006 remnant as the extension of the radio emission: the entire spectrum can be fitted when synchrotron losses are included. The model implies that while several percent of the shock energy goes into The magnetic field, only 2 x 10/sup -5/ of the shock energy goes into relativistic electrons.

Reynolds, S.P.; Chevalier, R.A.

1981-05-01

270

High energy neutrinos from gamma-ray bursts with precursor supernovae.  

PubMed

The high energy neutrino signature from proton-proton and photo-meson interactions in a supernova remnant shell ejected prior to a gamma-ray burst provides a test for the precursor supernova, or supranova, model of gamma-ray bursts. Protons in the supernova remnant shell and photons entrapped from a supernova explosion or a pulsar wind from a fast-rotating neutron star remnant provide ample targets for protons escaping the internal shocks of the gamma-ray burst to interact and produce high energy neutrinos. We calculate the expected neutrino fluxes, which can be detected by current and future experiments. PMID:12857183

Razzaque, Soebur; Mszros, Peter; Waxman, Eli

2003-06-20

271

SPECTROSCOPIC DETECTION OF CARBON MONOXIDE IN THE YOUNG SUPERNOVA REMNANT CASSIOPEIA A  

SciTech Connect

We report the detection of carbon monoxide (CO) emission from the young supernova remnant Cassiopeia A (Cas A) at wavelengths corresponding to the fundamental vibrational mode at 4.65 {mu}m. We obtained AKARI Infrared Camera spectra toward four positions which unambiguously reveal the broad characteristic CO ro-vibrational band profile. The observed positions include unshocked ejecta at the center, indicating that CO molecules form in the ejecta at an early phase. We extracted a dozen spectra across Cas A along the long 1' slits and compared these to simple CO emission models in local thermodynamic equilibrium to obtain first-order estimates of the excitation temperatures and CO masses involved. Our observations suggest that significant amounts of carbon may have been locked up in CO since the explosion 330 years ago. Surprisingly, CO has not been efficiently destroyed by reactions with ionized He or the energetic electrons created by the decay of the radiative nuclei. Our CO detection thus implies that less carbon is available to form carbonaceous dust in supernovae than is currently thought and that molecular gas could lock up a significant amount of heavy elements in supernova ejecta.

Rho, J.; Reach, W. T. [Stratospheric Observatory for Infrared Astronomy, Universities Space Research Association, NASA Ames Research Center, MS 211-3, Moffett Field, CA 94035 (United States); Onaka, T. [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Cami, J., E-mail: jrho@sofia.usra.edu, E-mail: wreach@sofia.usra.edu, E-mail: onaka@astron.s.u-tokyo.ac.jp, E-mail: jcami@uwo.ca [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada)

2012-03-15

272

A Search for Evidence of Non-Thermal Emission from the Supernova Remnants 37A/B  

NASA Astrophysics Data System (ADS)

The ADP grant NAG5-9211 entitled 'A Search for Evidence of Non-Thermal Emission from the Supernova Remnants 37 A/B' was not used to support an analysis of the ASCA data for these two remnants because the ASCA mission ended before the remnants were observed. The grant was used to support similar research on two remnants in the Large Magellanic Cloud, N132D and N 103B. An analysis of the Chandra data for these two remnants exhibits some evidence of non-thermal emission from small regions in the remnants. The X-ray spectra for these regions can not be adequately described by a single thermal X-ray emission model. However, if an X-ray synchrotron component is also included, the spectral data can be well described by the model and the values of the fit parameters are consistent with the values expected. These results were presented at the 199th Meeting of the American Astronomical Society. In summary, the grant has enabled us to strengthen the evidence that supernova remnants outside our Galaxy can also accelerate electrons to very-high energies. The results of this analysis will be published soon in the Astrophysical Journal,

Oliversen, R.

2002-01-01

273

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

NASA Astrophysics Data System (ADS)

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 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 to: 1) infer the mass of their progenitor stars through X-ray spectroscopic studies of the thermally emitting supernova ejecta, and 2) investigate the physical properties of their hosting SNRs and ambient conditions. We here highlight our detailed studies of two SNRs: G292.2-0.5, associated with the HBP J1119-6127, and Kes 73, associated with the AXP 1E 1841-045, and summarize the current view of the other (handful) HBP/magnetar-SNR associations.

Safi-Harb, S.; Kumar, H. S.

2013-03-01

274

Ultrahigh energy cosmic ray nuclei from extragalactic pulsars and the effect of their Galactic counterparts  

NASA Astrophysics Data System (ADS)

The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 1019 eV as reported by the Auger Observatory. Pulsar acceleration implies a hard injection spectrum ( ~ E-1) due to pulsar spin down and a maximum energy Emax ~ Z 1019 eV due to the limit on the spin rate of neutron stars. We have previously shown that the escape through the young supernova remnant softens the spectrum, decreases slightly the maximum energy, and generates secondary nuclei. Here we show that the distribution of pulsar birth periods and the effect of propagation in the interstellar and intergalactic media modifies the combined spectrum of all pulsars. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 1016 and 1018 eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, which is uncertain, differing between Auger Observatory and Telescope Array. The contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum just below the ankle, depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy.

Fang, Ke; Kotera, Kumiko; Olinto, Angela V.

2013-03-01

275

Gamma-Ray Emission from the Shell of Supernova Remnant W44 Revealed by the Fermi LAT  

Microsoft Academic Search

Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~1015 electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 108 electron volts and 3 1011 electron volts. The detection of a

A. A. Abdo; M. Ackermann; M. Ajello; 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; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; J. M. Casandjian; C. Cecchi; . elik; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; I. Cognard; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; S. Cutini; C. D. Dermer; A. de Angelis; F. de Palma; S. W. Digel; E. do Couto e Silva; P. S. Drell; R. Dubois; D. Dumora; C. Espinoza; C. Farnier; C. Favuzzi; S. J. Fegan; W. B. Focke; P. Fortin; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; G. Giavitto; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; A. K. Harding; M. Hayashida; E. Hays; R. E. Hughes; M. S. Jackson; G. Jhannesson; A. S. Johnson; T. J. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; J. Katsuta; N. Kawai; M. Kerr; J. Kndlseder; M. L. Kocian; M. Kramer; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. G. Lyne; G. M. Madejski; A. Makeev; M. N. Mazziotta; J. E. McEnery; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; T. Nakamori; P. L. Nolan; J. P. Norris; A. Noutsos; E. Nuss; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; D. Paneque; D. Parent; V. Pelassa; M. Pesce-Rollins; F. Piron; T. A. Porter; S. Rain; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; 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; J. D. Scargle; C. Sgr; E. J. Siskind; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; B. W. Stappers; F. W. Stecker; M. S. Strickman; D. J. Suson; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; G. Theureau; D. J. Thompson; L. Tibaldo; O. Tibolla; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; V. Vasileiou; C. Venter; N. Vilchez; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; R. Yamazaki; T. Ylinen; M. Ziegler

2010-01-01

276

AN X-RAY, OPTICAL, AND RADIO SEARCH FOR SUPERNOVA REMNANTS IN THE NEARBY SCULPTOR GROUP Sd GALAXY NGC 300  

Microsoft Academic Search

We have conducted a multiwavelength (X-ray, optical, and radio) search for supernova remnants (SNRs) in the nearby Sculptor Group Sd galaxy NGC 300. Our Very Large Array (VLA) radio obser- vations at 6 cm and 20 cm have been combined with previously published optical results, our own optical image, and archived ROSAT X-ray data to search for new SNR candidates.

THOMAS G. PANNUTI; NEBOJSA DURIC; Yale Boulevard; CHRISTINA K. LACEY; W. M. GOSS; CHARLES G. HOOPES; N. Charles; A. M. WALTERBOS; MARCUS A. MAGNOR

2000-01-01

277

An X-Ray, Optical, and Radio Search for Supernova Remnants in the Nearby Sculptor Group Sd Galaxy NGC 300  

Microsoft Academic Search

We have conducted a multiwavelength (X-ray, optical, and radio) search for supernova remnants (SNRs) in the nearby Sculptor Group Sd galaxy NGC 300. Our Very Large Array (VLA) radio observations at 6 cm and 20 cm have been combined with previously published optical results, our own optical image, and archived ROSAT X-ray data to search for new SNR candidates. Of

Thomas G. Pannuti; Nebojsa Duric; Christina K. Lacey; W. M. Goss; Charles G. Hoopes; Ren A. M. Walterbos; Marcus A. Magnor

2000-01-01

278

An X-Ray, Optical, and Radio Search for Supernova Remnants in the Nearby Sculptor Group Sd Galaxy NGC 7793  

Microsoft Academic Search

This paper is the second in a series devoted to examining the multiwavelength properties of supernova remnants (SNRs) located in nearby galaxies. We consider here the resident SNRs in the nearby Sculptor group Sd galaxy NGC 7793. Using our own Very Large Array (VLA) radio observations at 6 and 20 cm, as well as archived ROSAT X-ray data, previously published

Thomas G. Pannuti; Nebojsa Duric; Christina K. Lacey; Annette M. N. Ferguson; Marcus A. Magnor; Caylin Mendelowitz

2002-01-01

279

Anisotropic Thermal Conduction in Supernova Remnants: Relevance to Hot-Gas Filling Factors in the Magnetized Interstellar Medium  

Microsoft Academic Search

We explore the importance of anisotropic thermal conduction in the evolution of supernova remnants by means of numerical simulations. The mean temperature of the bubble of hot gas is decreased by a factor of ~3 compared with simulations without thermal conduction, together with an increase in the mean density of hot gas by a similar factor. Thus, thermal conduction greatly

David A. Tilley; Dinshaw S. Balsara

2006-01-01

280

First VLBI Detection of the Radio Remnant of Supernova 1987A: Evidence for Small-scale Features  

Microsoft Academic Search

We present a detailed analysis of the first very long baseline interferometry\\u000a(VLBI) detection of the radio remnant of supernova 1987A. The VLBI data taken\\u000ain 2007 and 2008 at 1.4 and 1.7 GHz, respectively, provide images sensitive to\\u000aangular scales from 0.1\\

C.-Y. Ng; T. M. Potter; L. Staveley-Smith; S. Tingay; B. M. Gaensler; C. Phillips; A. K. Tzioumis; G. Zanardo

2010-01-01

281

Cosmic-Ray Acceleration at the Forward Shock in Tycho's Supernova Remnant: Evidence from Chandra X-Ray Observations  

Microsoft Academic Search

We present evidence for cosmic-ray acceleration at the forward shock in Tycho's supernova remnant (SNR) from three X-ray observables: (1) the proximity of the contact discontinuity to the forward shock, or blast wave, (2) the morphology of the emission from the rim of Tycho, and (3) the spectral nature of the rim emission. We determine the locations of the blast

Jessica S. Warren; John P. Hughes; Carles Badenes; Parviz Ghavamian; Christopher F. McKee; David Moffett; Paul P. Plucinsky; Cara Rakowski; Estela Reynoso; Patrick Slane

2005-01-01

282

Balmer-dominated Spectra of Nonradiative Shocks in the Cygnus Loop, RCW 86, and Tycho Supernova Remnants  

Microsoft Academic Search

We present an observational and theoretical study of the optical emission from nonradiative shocks in three supernova remnants: the Cygnus Loop, RCW 86, and Tycho. The spectra of these shocks are dominated by collisionally excited hydrogen Balmer lines, which have both a broad component caused by proton-neutral charge exchange and a narrow component caused by excitation of cold neutrals entering

Parviz Ghavamian; John Raymond; R. Chris Smith; Patrick Hartigan

2001-01-01

283

The End of Amnesia: A New Method for Measuring the Metallicity of Type Ia Supernova Progenitors Using Manganese Lines in Supernova Remnants  

NASA Astrophysics Data System (ADS)

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 K? X-ray lines in the Tycho supernova remnant recently detected by Suzaku, to derive a metallicity of log(Z)=-1.32+0.67-0.33 for the progenitor of this supernova, which corresponds to log(Z/Zsolar)=0.60+0.31-0.60 according to the latest determination of the solar metallicity by Asplund and coworkers. 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.

Badenes, Carles; Bravo, Eduardo; Hughes, John P.

2008-06-01

284

Evolution of the Radio Remnant of Supernova 1987A: Morphological Changes from Day 7000  

NASA Astrophysics Data System (ADS)

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^{+150}_ {-200} km s1 between day 4000 and 7000 to 2400^{+100}_{-200} km s1 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 s1 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.; Zanardo, G.; Potter, T. M.; Staveley-Smith, L.; Gaensler, B. M.; Manchester, R. N.; Tzioumis, A. K.

2013-11-01

285

The morphology and dynamics of a multi-lobed supernova remnant in the LMC (DEM 34a, N11L)  

NASA Astrophysics Data System (ADS)

Photon-counting imagery of the 1624 pc supernova remnant, DEM 34a, has revealed a secondary lobe projecting from the bright ring of emission line filaments. Spatially resolved, long-slit echelle spectra of the H? and [N II] emission lines show that complex motions are occurring within this remnant. Multiple lobes expanding with velocities of up to 350 km s-1 are present. The total H? flux of DEM 34a is measured as 2.110-12erg s-1cm-2 (uncorrected for interstellar extinction) and the H?/[N II] 6584+6548 and H?/[S II] 6731+6716 brightness ratios as 3.2 and 1.1 respectively. These values are consistent with a 71 km s-1 velocity for the radiative shock which ionizes this supernova remnant.

Meaburn, John

1987-12-01

286

Radio-Continuum Observations of Small, Radially Polarised Supernova Remnant J0519-6902 in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We report on new Australian Telescope Compact Array (ATCA) observations of SNR J0519-6902. The Supernova Remnant (SNR) is small in size (8 pc) and exhibits a typical SNR spectrum with ? = -0.53 0.07}, with steeper spectral indices towards the northern limb of the remnant. SNR J0519-6902 contains a low level of radially orientated polarisation at wavelengths of 3 and 6 cm, which is typical of younger SNRs. A fairly strong magnetic field was estimated to 171 ?G. The remnant appears to be the result of a typical Type Ia supernova, sharing many properties with another small and young Type Ia LMC SNR, J0509-6731.

Bozzetto, L. M.; Filipovic, M. D.; Urosevic, D.; Crawford, E. J.

2012-12-01

287

Flux limits for TeV emission from pulsars  

Microsoft Academic Search

Observations have been made with the University of Durham Mark 6 telescope of a number of Southern hemisphere supernova remnants and young pulsars (Vela pulsar, PSR B1055-52, PSR J1105-6107, PSR J0537-6910 and PSR B0540-69). No VHE gamma ray emission, either steady or pulsed, has been detected from these objects. The implications of these results for theories of high energy gamma

P. M. Chadwick; K. Lyons; T. J. L. McComb; K. J. Orford; J. L. Osborne; S. M. Rayner; S. E. Shaw; K. E. Turver

2000-01-01

288

Flux limits for TeV emission from pulsars  

Microsoft Academic Search

Observations have been made with the University of Durham Mark 6 telescope of a number of Southern hemisphere supernova remnants and young pulsars (Vela pulsar, PSR B1055?52,PSR J1105?6107,PSR J0537?6910 and PSR B0540?69). No VHE gamma ray emission, either steady or pulsed, has been detected from these objects. The implications of these results for theories of high energy gamma ray production

P. M. Chadwick; K. Lyons; T. J. L. McComb; K. J. Orford; J. L. Osborne; S. M. Rayner; S. E. Shaw; K. E. Turver

2000-01-01

289

Secular decrease in the 927-MHz flux of the supernova remnants Cassiopeia A and Taurus A  

SciTech Connect

Relative measurements of the radio flux density of the supernova remnants Cas A and Tau A at 927-MHz frequency were carried out with the 10-m radio telescope of the Staraya Pustyn' station, Gor'kii Radiophysics Institute, in October--December 1977. The Orion Nebula and the radio galaxies Cygnus A and Virgo A served as comparison sources. Comparison of the results with absolute measurements made in October 1962 indicates that over the 15-yr interval the radio flux of Cas A dropped by (14.2 +- 0.6) % (mean annual decrease, (0.95 +- 0.04) %), while the Tau A flux dropped by (2.7 +- 0.1) % (mean annual decrease, (0.18 +- 0.01) %).

Vinyaikin, E.N.; Razin, V.A.

1979-09-01

290

Fermi Large Area Telescope Observations of Supernova Remnants Interacting with Molecular Clouds  

NASA Astrophysics Data System (ADS)

We report the detection of ?-ray emission coincident with four supernova remnants (SNRs) using data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. G349.7+0.2, CTB 37A, 3C 391, and G8.7-0.1 are SNRs known to be interacting with molecular clouds, as evidenced by observations of hydroxyl (OH) maser emission at 1720 MHz in their directions. SNR shocks are expected to be sites of cosmic-ray acceleration, and clouds of dense material can provide effective targets for production of ?-rays from ?0 decay. The observations reveal unresolved sources in the direction of G349.7+0.2, CTB 37A, and 3C 391, and a possibly extended source coincident with G8.7-0.1, all with significance levels greater than 10?.

Castro, Daniel; Slane, Patrick

2010-07-01

291

3-D Rendering of the Supernova Remnant 1E0102.2-7219 in the SMC  

NASA Astrophysics Data System (ADS)

Recent papers suggest that the young, oxygen-rich supernova remnant 1E 0102.2-7219 (E0102) in the Small Magellanic Cloud has an asymmetric bipolar structure. Using data from the Rutgers/CTIO Fabry-Prot interferometer, we examine the kinematics and structure of this intriguing object in the light [O III]5007 emission. (Some aspects of these data were previously discussed by Eriksen et al. 2001.) The data cube consists of 72 isovelocity slices covering the complete velocity range of the optical emission and separated by 100 km/s with seeing limited spatial resolution. The data can be rendered by PINGsoft 2, an IDL Integral Field Spectroscopy Software package designed to visualize, analyze, and manipulate spectroscopy 3-D datasets. We examine the spatio-kinematic structure of E0102 and compare our conclusions to recent analyses by other investigators, such as Vogt & Dopita (2010).

Lyle, Jake; Garges, C.; Morse, J. A.

2013-06-01

292

3-D Rendering of the Supernova Remnant 1E0102.2-7219 in the SMC  

NASA Astrophysics Data System (ADS)

Recent papers suggest that the young, oxygen-rich supernova remnant 1E 0102.2-7219 (E0102) in the Small Magellanic Cloud has an asymmetric bipolar structure. Using data from the Rutgers/CTIO Fabry-Prot interferometer, we examine the kinematics and structure of this intriguing object in the light [O III]5007 emission. (Some aspects of these data were previously discussed by Eriksen et al. 2001.) The data cube consists of 45 isovelocity slices covering the complete velocity range of the optical emission and separated by 100 km/s with seeing limited spatial resolution. The data can be rendered by PINGsoft 2, an IDL Integral Field Spectroscopy Software package designed to visualize, analyze, and manipulate spectroscopy 3-D datasets. We examine the spatio-kinematic structure of E0102 and compare our conclusions to recent analyses by other investigators, such as Vogt & Dopita (2010).

Lyle, Jake; Garges, C.; Morse, J. A.

2013-06-01

293

Search for Ultrahigh Energy Gamma-Ray Emission from Supernova Remnants  

NASA Astrophysics Data System (ADS)

The majority of the cosmic rays in our galaxy with energies in the range of ~ 10(9) --10(14) 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 hypothesis. The Energetic Gamma-Ray Telescope Experiment (EGRET) has reported several sources of gamma rays in the energy range of ~ 10(8) --10(10) eV whose coordinates are correlated with SNRs. Five of these are within the field of view of the CYGNUS extensive air shower detector. No evidence of gamma-ray emission above ~ 10(14) eV is found for these five SNRs in the CYGNUS data set. The flux upper limits from the CYGNUS experiment and the fluxes measured with the EGRET instrument are compared. The implications for models of gamma-ray production in these five SNRs will be presented.

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

1994-12-01

294

Gamma-ray and X-ray Observations Towards the Gamma-Cygni Supernova Remnant  

NASA Astrophysics Data System (ADS)

We report on observations of the source VER J2019+407 towards the Gamma-Cygni supernova remnant. Very high energy (> 320 GeV) gamma-ray emission from the source was detected by the VERITAS observatory, an array of four 12-meter imaging atmospheric Cherenkov telescopes based near Tucson, Arizona. The proximity of this source to a diffuse region of gamma-ray emission detected by the Fermi Space Telescope increases its significance, and may suggest a connection between the two. To further investigate the properties of VER J2019+407, we have obtained a 50 ks Chandra observation of this region. Analysis of the Chandra data, and implications for the gamma-ray source, will be presented.

Dwarkadas, Vikram; Weinstein, A.; Theiling, M.; VERITAS Collaboration

2013-04-01

295

C IV EMISSION-LINE DETECTION OF THE SUPERNOVA REMNANT RCW 114  

SciTech Connect

We report the detection of the C IV lambdalambda1548,1551 emission line in the region of the RCW 114 nebula using the FIMS/SPEAR data. The observed C IV line intensity indicates that RCW 114 is much closer to us than WR 90, a Wolf-Rayet star that was thought to be associated with RCW 114 in some of the previous studies. We also found the existence of a small H I bubble centered on WR 90, with a different local standard of rest velocity range from that of the large H I bubble which was identified previously as related to RCW 114. These findings imply that the RCW 114 nebula is likely an old supernova remnant that is not associated with WR 90. Additionally, the global morphologies of the C IV, Halpha, and H I emissions show that RCW 114 has evolved in a non-uniform interstellar medium.

Kim, I.-J.; Min, K.-W. [Korea Advanced Institute of Science and Technology, 305-701 Daejeon (Korea, Republic of); Seon, K.-I.; Han, W. [Korea Astronomy and Space Science Institute, 305-348 Daejeon (Korea, Republic of); Edelstein, J., E-mail: ijkim@kasi.re.k [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)

2010-02-01

296

Discovery of the Small-diameter, Young Supernova Remnant G354.4+0.0  

NASA Astrophysics Data System (ADS)

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 ~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 ~100-500 yr.

Roy, Subhashis; Pal, Sabyasachi

2013-09-01

297

The Three-dimensional Structure of the Cassiopeia A Supernova Remnant. I. The Spherical Shell  

NASA Astrophysics Data System (ADS)

The three-dimensional structure of the Cassiopeia A supernova remnant is explored via 73 long-slit optical spectra (spanning 6250-7600 ) which cross the face and "jet" region of the nebula. We extracted position, radial velocity, and line intensity information from nearly 25,000 cross sections of these original data, resulting in a library of 3663 fast-moving knots (FMKs) and 450 quasi-stationary flocculi (QSFs) detections. We performed an iterative least-squares spherical fit to the data, using this to convert radial velocities to line-of-sight distances. We have built up a picture of the remnant as a spherical circumstellar shell of 104"50"7 radius, corresponding to 5.3 1018 cm (1.7 pc). The center on the sky is displaced by 8".7 west and 12".6 north of the proper motion center. The velocity center of our fitted sphere has been redshifted by 77040 km s-1 from the presumed expansion center at zero velocity. This expansion of the ejecta from a displaced center accounts for the observed radial velocity difference at the front and back faces. The average rate of expansion of the FMKs is 529090 km s-1, while the asymmetric values are 4520 km s-1 at the blueshifted face, and 6060 km s-1 at the redshifted face. Based on a comparison of our suite of radial velocities with all the available proper-motion and age data, we find the distance to Cas A to be 3.4+0.3-0.1 kpc. Our kinematic analysis shows the optically emitting ejecta of Cas A have been slowed certainly by less than 7%, and probably by less than 4% and that the velocity of the reverse shock driven into the knots is about 200 km s-1. We conclude that the center of expansion of the supernova is displaced by about 0.36 pc (1.1 1018 cm) to the northwest and front of the geometric center of the bubble. The geometry suggests that the density of the surrounding medium is greater in the direction of displacement. The asymmetrically distributed radial velocities of the QSFs, of which 76% are blueshifted, also support this interpretation. Line ratios suggest that the pressure is higher on the front side of the remnant than on the back. There is a global trend of increasing electron density with radial velocity in this direction, and a stronger trend of increasing [O II]/[S II] from back to front. We suggest that this is due to collisional deexcitation of [S II] on the high-pressure side of the remnant, rather than a real composition trend. We also see evidence for density variations in both the shell and ejecta, concluding that the front face of the composite shell is of higher density than the far face, and that the blueshifted ejecta may be of higher density than that at the far face. However, in this study we see no evidence for any ordered change in abundances of the ejecta across Cas A. The weight of observational evidence suggests that the general form of the Cas A supernova remnant is due to the expansion of ejecta from a displaced center within an approximately spherical shell. We have concluded that there is no optical evidence for a dual-hemisphere model in the velocity structure of Cas A. In particular, we find that the outer radio emission must truly lie outside the inner radio and optical shell. The inner shell is made up of decelerated circumstellar material and the SN material which was ejected at highest velocity. The optical FMKs consist of newly interacting knots of ejecta which are just undergoing deceleration and are distributed in rings on the surface of the sphere.

Reed, Jeri E.; Hester, J. Jeff; Fabian, A. C.; Winkler, P. F.

1995-02-01

298

SUBARU HIGH-RESOLUTION SPECTROSCOPY OF STAR G IN THE TYCHO SUPERNOVA REMNANT  

SciTech Connect

It is widely believed that Type Ia supernovae (SNe Ia) originate in binary systems where a white dwarf accretes material from a companion star until its mass approaches the Chandrasekhar mass and carbon is ignited in the white dwarf's core. This scenario predicts that the donor star should survive the supernova (SNe) explosion, providing an opportunity to understand the progenitors of SNe Ia. In this paper, we argue that rotation is a generic signature expected of most nongiant donor stars that is easily measurable. Ruiz-Lapuente et al. examined stars in the center of the remnant of SN 1572 (Tycho SN) and showed evidence that a subgiant star (Star G by their naming convention) near the remnant's center was the system's donor star. We present high-resolution (R {approx_equal} 40, 000) spectra taken with the High Dispersion Spectrograph on Subaru of this candidate donor star and measure the star's radial velocity as 79 {+-} 2 km s{sup -1} with respect to the local standard of rest and put an upper limit on the star's rotation of 7.5 km s{sup -1}. In addition, by comparing images that were taken in 1970 and 2004, we measure the proper motion of Star G to be {mu} {sub l} = -1.6 {+-} 2.1 mas yr{sup -1} and {mu} {sub b} = -2.7 {+-} 1.6 mas yr{sup -1}. We demonstrate that all of the measured properties of Star G presented in this paper are consistent with those of a star in the direction of Tycho SN that is not associated with the SN event. However, we discuss an unlikely, but still viable scenario for Star G to be the donor star, and suggest further observations that might be able to confirm or refute it.

Kerzendorf, Wolfgang E.; Schmidt, Brian P.; Yong, David [Research School of Astronomy and Astrophysics, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Asplund, M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, Postfach 1317, D-85748 Garching (Germany); Nomoto, Ken'ichi [Institute for the Physics and Mathematics of the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan); Podsiadlowski, Ph. [Department of Astrophysics, University of Oxford, Oxford, OX1 3RH (United Kingdom); Frebel, Anna [McDonald Observatory, University of Texas, 1 University Station C1402, Austin, TX 78712-0259 (United States); Fesen, Robert A. [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755 (United States)], E-mail: wkerzend@mso.anu.edu.au, E-mail: brian@mso.anu.edu.au, E-mail: yong@mso.anu.edu.au, E-mail: nomoto@astron.s.u-tokyo.ac.jp, E-mail: podsi@astro.ox.ac.uk, E-mail: anna@astro.as.utexas.edu, E-mail: fesen@snr.dartmouth.edu

2009-08-20

299

The imprint of a symbiotic binary progenitor on the properties of Kepler's supernova remnant  

NASA Astrophysics Data System (ADS)

We present a model for the type Ia supernova remnant (SNR) of SN 1604, also known as Kepler's SNR. We find that its main features can be explained by a progenitor model of a symbiotic binary consisting of a white dwarf and an AGB donor star with an initial mass of 4-5 M?. The slow, nitrogen-rich wind emanating from the donor star has partially been accreted by the white dwarf, but has also created a circumstellar bubble. On the basis of observational evidence, we assume that the system moves with a velocity of 250 km s-1. Owing to the spatial velocity, the interaction between the wind and the interstellar medium has resulted in the formation of a bow shock, which can explain the presence of a one-sided, nitrogen-rich shell. We present two-dimensional hydrodynamical simulations of both the shell formation and the SNR evolution. The SNR simulations show good agreement with the observed kinematic and morphological properties of Kepler's SNR. In particular, the model reproduces the observed expansion parameters (m = V/(R/t)) of m ? 0.35 in the north and m ? 0.6 in the south of Kepler's SNR. We discuss the variations among our hydrodynamical simulations in light of the observations, and show that part of the blast wave may have completely traversed through the one-sided shell. The simulations suggest a distance to Kepler's SNR of 6 kpc, or otherwise imply that SN 1604 was a sub-energetic type Ia explosion. Finally, we discuss the possible implications of our model for type Ia supernovae and their remnants in general.

Chiotellis, A.; Schure, K. M.; Vink, J.

2012-01-01

300

Application of a 3D, Adaptive, Parallel, MHD Code to Supernova Remnant Simulations  

NASA Astrophysics Data System (ADS)

We at Michigan have a computational model, BATS-R-US, which incorporates several modern features that make it suitable for calculations of supernova remnant evolution. In particular, it is a three-dimensional MHD model, using a method called the Multiscale Adaptive Upwind Scheme for MagnetoHydroDynamics (MAUS-MHD). It incorporates a data structure that allows for adaptive refinement of the mesh, even in massively parallel calculations. Its advanced Godunov method, a solution-adaptive, upwind, high-resolution scheme, incorporates a new, flux-based approach to the Riemann solver with improved numerical properties. This code has been successfully applied to several problems, including the simulation of comets and of planetary magnetospheres, in the 3D context of the Heliosphere. The code was developed under a NASA computational grand challenge grant to run very rapidly on parallel platforms. It is also now being used to study time-dependent systems such as the transport of particles and energy from solar coronal mass ejections to the Earth. We are in the process of modifying this code so that it can accommodate the very strong shocks present in supernova remnants. Our test case simulates the explosion of a star of 1.4 solar masses with an energy of 1 foe, in a uniform background medium. We have performed runs of 250,000 to 1 million cells on 8 nodes of an Origin 2000. These relatively coarse grids do not allow fine details of instabilities to become visible. Nevertheless, the macroscopic evolution of the shock is simulated well, with the forward and reverse shocks visible in velocity profiles. We will show our work to date. This work was supported by NASA through its GSRP program.

Kominsky, P.; Drake, R. P.; Powell, K. G.

2001-05-01

301

Two-dimensional magnetohydrodynamics simulations of young Type Ia supernova remnants  

NASA Astrophysics Data System (ADS)

Using two-dimensional magnetohydrodynamics (MHD) simulations, we investigate the dynamical properties of Type Ia supernova remnants (SNRs) evolved either in a uniform ambient medium or from an interaction with a dense clump. The initial conditions assume that the expansion of the supernova ejecta is of free inertia with a power-law density distribution in the outer part of the ejecta. To include the effects of the diffusive shock acceleration process and the escape of the accelerated particles from the shock front, we use different adiabatic indices in the simulations to study the dynamical evolution of the Type Ia SNRs. Moreover, we investigate the interactions of a SNR with either a small or a large clump. A double-shock structure with a contact discontinuity is produced as the ejecta flow supersonically in the ambient medium; Rayleigh-Taylor instability is clearly shown as fingers near the contact discontinuity in the contour maps of density, and a high density and a high magnetic field can be triggered because of the instability around the Rayleigh-Taylor fingers. We perform simulations with different adiabatic indices, and the results show that a narrower intershock region is produced with a smaller adiabatic index because a larger compression ratio for the SNR shock is induced. The influence of the Rayleigh-Taylor instability on the morphologies of both the forward and reverse shocks is more significant with a smaller adiabatic index. Finally, the simulations of a SNR interacting with a dense clump show that the morphology of the remnant is greatly twisted after the collision, and a filament with a high density and a high magnetic field can be produced as a SNR colliding with a large dense clump.

Fang, Jun; Zhang, Li

2012-08-01

302

Development of an x-ray imaging proportional counter and an analysis of Tycho's supernova remnant  

SciTech Connect

A soft X-ray imaging proportional counter was developed for use in X-ray astronomy. The detector, a drift multiwire proportional counter, determines the position of the site of X-ray absorption in the detector in two orthogonal directions using the center-of-gravity centroid determination technique. Spatial resolutions of 0.2 millimeters full width at half maximum and 0.5 millimeters full width at half maximum have been obtained at X-ray energies of 0.94 and 0.28 kiloelectron volts, respectively. Energy resolutions of 65 percent full width at half maximum and 110 percent full width at half maximum have been obtained at these energies. The detector and processing electronics were integrated into a rocket-borne X-ray telescope payload capable of providing angular resolutions of 1.0 arcminutes full width at half maximum and 1.3 arcminutes full width at half maximum at X-ray energies of 0.94 and 0.28 kiloelectron volts, respectively. X-ray imaging observations of Tycho's supernova remnant were obtained with the Einstein Observatory imaging proportional counter. The remnant appears as an incomplete shell of radius 3.5 parsecs in the adiabatic phase of evolution. The X-ray and radio shells are spatially coincident, although uncorrelated in intensity. The luminosity at a distance of 3 kiloparsecs is (5.3 +- 1.3) x 10/sup 36/ ergs per second. The current shock velocity is 3400 +- 140 kilometers per second. An initial blast energy is found of 2.5 x 10/sup 51/ ergs and an average ambient density is found in the vicinity of Tycho of approximately 3 atoms per cubic centimeter. The mass swept up by the expanding shock wave is estimated at about 20 solar masses. A range of 0.3 to 3 solar masses has been placed on the supernova ejected mass.

Reid, P.B.

1982-01-01

303

Spatially-resolved Spectroscopy of the IC443 Pulsar Wind Nebula and Environs  

NASA Astrophysics Data System (ADS)

Deep Chandra ACIS observations of the region around the putative pulsar, CXO J061705.3+222127, in the supernova remnant IC443 confirm that (1) the spectrum and flux of the central object are consistent with a rotation-powered pulsar interpretation, (2) the non-thermal surrounding nebula is likely powered by a pulsar wind, and (3) the thermal-dominated spectrum at greater distances is consistent with emission from the supernova remnant. The observations further reveal, for the first time, a ring-like morphology surrounding the pulsar and a jet-like structure oriented roughly north-south across the ring and through the pulsar location. The cometary shape of the nebula, suggesting motion towards the southwest, appears to be subsonic; there is no evidence for a strong bow shock and the ring, presumably formed at a wind termination shock, is not distorted by motion through the ambient medium.

Swartz, Douglas A.; Weisskopf, M. C.; Zavlin, V.; Bucciantini, N.; Clarke, T. E.; Karovska, M.; Pavlov, G. G.; van der Horst, A.; Yukita, M.

2013-04-01

304

DISCOVERY OF TeV GAMMA-RAY EMISSION FROM TYCHO'S SUPERNOVA REMNANT  

SciTech Connect

We report the discovery of TeV gamma-ray emission from the Type Ia supernova remnant (SNR) G120.1+1.4, known as Tycho's SNR. Observations performed in the period 2008-2010 with the VERITAS ground-based gamma-ray observatory reveal weak emission coming from the direction of the remnant, compatible with a point source located at 00{sup h}25{sup m}27.{sup s}0, + 64{sup 0}10'50'' (J2000). The TeV photon spectrum measured by VERITAS can be described with a power law dN/dE = C(E/3.42 TeV){sup -}{Gamma} with {Gamma} = 1.95 {+-} 0.51{sub stat} {+-} 0.30{sub sys} and C = (1.55 {+-} 0.43{sub stat} {+-} 0.47{sub sys}) x 10{sup -14} cm{sup -2} s{sup -1} TeV{sup -1}. The integral flux above 1 TeV corresponds to {approx}0.9% of the steady Crab Nebula emission above the same energy, making it one of the weakest sources yet detected in TeV gamma rays. We present both leptonic and hadronic models that can describe the data. The lowest magnetic field allowed in these models is {approx}80 {mu}G, which may be interpreted as evidence for magnetic field amplification.

Acciari, V. A.; Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Aliu, E.; Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Bradbury, S. M. [School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cesarini, A. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Duke, C. [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); Finnegan, G., E-mail: dbsaxon@udel.edu, E-mail: wakely@uchicago.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)

2011-04-01

305

Expected Gamma-Ray Emission of Supernova Remnant SN 1987A  

NASA Astrophysics Data System (ADS)

A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is employed to re-examine the nonthermal properties of the remnant of SN 1987A for an extended evolutionary period of 5-100 yr. It is shown that an efficient production of nuclear CRs leads to a strong modification of the outer SNR shock and to a large downstream magnetic field B d ? 20 mG. The shock modification and the strong field are required to yield the steep radio emission spectrum observed, as well as the considerable synchrotron cooling of high-energy electrons which diminishes their X-ray synchrotron flux. These features are also consistent with the existing X-ray observations. The expected ?-ray energy flux at TeV energies at the current epoch is nearly epsilon? F ? ? 4 10-13 erg cm2 s-1 under reasonable assumptions about the overall magnetic field topology and the turbulent perturbations of this field. The general nonthermal strength of the source is expected to increase roughly by a factor of two over the next 15-20 years thereafter, it should decrease with time in a secular form.

Berezhko, E. G.; Ksenofontov, L. T.; Vlk, H. J.

2011-05-01

306

Modeling of laser-generated radiative blast waves, with applications to late-term supernova remnants  

NASA Astrophysics Data System (ADS)

The goal of laser astrophysics is to provide a means by which aspects of specific astrophysical phenomena can be reproduced in the laboratory. Although the hydrodynamic instabilities of early supernova remnants have already been studied using this method, the role of significant radiative losses in shock propagation (for example, in late-term remnants) has only been imperfectly modeled. This thesis introduces an improved self-similar analytic approach to radiative blast-wave evolution where the total amount of energy loss remains constant in proportion to the energy flux entering the shock front. The approximation is solved for the cases in which both energy loss from the shock front and heating of the shock (due to the presence of ionization precursors) are significant. Because this solution is independent of the exact method of cooling, it is appropriate for both the laboratory and astrophysical regimes. In addition, this thesis applies the analytic approximation to laboratory- produced radiative blast waves as well as to numerical models of these experimental blast waves. These results will allow for better design of laser-based experiments with further applications to astrophysical phenomena, as well as for an increase in the understanding of the challenges involved in scaling radiative phenomena between laboratory experiments and astrophysical theory.

Keilty, Katherine Anne

2003-11-01

307

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

SciTech Connect

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 {gamma}-ray emission coincident with CTB 109, using 37 months of data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. We study the broadband characteristics of the remnant using a model that includes hydrodynamics, efficient cosmic-ray (CR) acceleration, nonthermal emission, and a self-consistent calculation of the X-ray thermal emission. We find that the observations can be successfully fit with two distinct parameter sets, one where the {gamma}-ray emission is produced primarily by leptons accelerated at the SNR forward shock and the other where {gamma}-rays produced by forward shock accelerated CR ions dominate the high-energy emission. Consideration of thermal X-ray emission introduces a novel element to the broadband fitting process, and while it does not rule out either the leptonic or the hadronic scenarios, it constrains the parameter sets required by the model to fit the observations. Moreover, the model that best fits the thermal and nonthermal emission observations is an intermediate case, where both radiation from accelerated electrons and hadrons contribute almost equally to the {gamma}-ray flux observed.

Castro, Daniel [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Slane, Patrick; Patnaude, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ellison, Donald C. [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States)

2012-09-01

308

The X-Ray Line Emission from the Supernova Remnant W49B  

NASA Astrophysics Data System (ADS)

The Galactic supernova remnant W49B has one of the most impressive X-ray emission-line spectra obtained with ASCA. We use both plasma line diagnostics and broadband model fits to show that the Si and S emission lines require multiple spectral components. The spectral data do not necessarily require individual elements to be spatially stratified, as suggested by earlier work, although when ASCA line images are considered, it is possible that Fe is stratified with respect to Si and S. Most of the X-ray-emitting gas is from ejecta, based on the element abundances required, but is surprisingly close to being in collisional ionization equilibrium. A high ionization age implies a high internal density in a young remnant. The fitted emission measure for W49B indicates a minimum density of 2 cm-3, with the true density likely to be significantly higher. W49B probably had a Type Ia progenitor, based on the relative element abundances, although a low-mass Type II progenitor is still possible. We find persuasive evidence for Cr and possibly Mn emission in the ASCA spectrum-the first detection of these elements in X-rays from a cosmic source.

Hwang, Una; Petre, Robert; Hughes, John P.

2000-04-01

309

The Sub-Parsec Scale Radio Properties of Southern Starburst Galaxies. II. Supernova Remnants, the Supernova Rate, and the Ionised Medium in the NGC 4945 Starburst  

NASA Astrophysics Data System (ADS)

Wide-field, very long baseline interferometry observations of the nearby starburst galaxy NGC 4945, obtained with the Australian Long Baseline Array, have produced 2.3 GHz images over two epochs with a maximum angular resolution of 15 mas (0.3 pc). Fifteen sources were detected, 13 of which correspond to sources identified in higher frequency (3 cm and 12 mm) Australian Telescope Compact Array images. Four of the sources are resolved into shell-like structures ranging between 60 and 110 mas (1.1 to 2.1 pc) in diameter. From these data the spectra of 13 compact radio sources in NGC 4945 were modelled; nine were found to be consistent with free-free absorbed power laws and four with a simple power law spectrum. The free-free opacity is highest toward the nucleus but significantly varies throughout the nuclear region (?0 ~ 6 - 23), implying that the overall structure of the ionized medium is clumpy. Of the 13 sources, 10 have steep intrinsic spectra associated with synchrotron emission from supernova remnants, the remaining sources have flat intrinsic spectra which may be associated with thermal radio emission. A non-thermal source with a jet-like morphology is detected ~1'' from the assumed location of the active galactic nucleus. A Type II supernova rate upper limit of 15.3 yr-1 is determined for the inner 250 pc region of the galaxy at the 95% confidence level, based on the lack of detection of new sources in observations spanning 1.9 years and a simple model for the evolution of supernova remnants. A Type II supernova rate of >0.1(v/104) yr-1 is implied from estimates of supernova remnant source counts, sizes, and expansion rates, where v is the radial expansion velocity of the supernova remnant in km s-1. A star formation rate (SFR) of 2.4(v/104) < SFR(M >= 5 M sun) < 370 M sun yr-1 has been estimated directly from the supernova rate limits and is of the same order of magnitude as rates determined from integrated far-IR (1.5 M sun yr-1) and radio luminosities (14.4 1.4 (Q/8.8) M sun yr-1). The supernova rates and star formation rates determined for NGC 4945 are comparable to those of NGC 253 and M82.

Lenc, E.; Tingay, S. J.

2009-01-01

310

POLYCYCLIC AROMATIC HYDROCARBON PROCESSING IN THE BLAST WAVE OF THE SUPERNOVA REMNANT N132D  

SciTech Connect

We present Spitzer Infrared Spectrograph 14-36 {mu}m mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 {mu}m region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edge of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 {mu}m appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.

Tappe, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-72, Cambridge, MA 02138 (United States); Rho, J. [SOFIA Science Mission Operations/USRA, NASA Ames Research Center, MS 211-3, Moffett Field, CA 94035 (United States); Boersma, C. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Micelotta, E. R., E-mail: atappe@cfa.harvard.edu [Department of Physics and Astronomy, Western University, 1151 Richmond Street, London, Ontario N6A 3K7 (Canada)

2012-08-01

311

Polycyclic Aromatic Hydrocarbon Processing in the Blast Wave of the Supernova Remnant N132D  

NASA Astrophysics Data System (ADS)

We present Spitzer Infrared Spectrograph 14-36 ?m mapping observations of the supernova remnant N132D in the Large Magellanic Cloud. This study focuses on the processing of polycyclic aromatic hydrocarbons (PAHs) that we previously identified in the southern blast wave. The mid-infrared spectra show strong continuum emission from shock-heated dust and a unique, nearly featureless plateau in the 15-20 ?m region, which we attribute to PAH molecules. The typical PAH emission bands observed in the surrounding interstellar medium ahead of the blast wave disappear, which indicates shock processing of PAH molecules. The PAH plateau appears most strongly at the outer edge of the blast wave and coincides with diffuse X-ray emission that precedes the brightest X-ray and optical filaments. This suggests that PAH molecules in the surrounding medium are swept up and processed in the hot gas of the blast wave shock, where they survive the harsh conditions long enough to be detected. We also observe a broad emission feature at 20 ?m appearing with the PAH plateau. We speculate that this feature is either due to FeO dust grains or connected to the processing of PAHs in the supernova blast wave shock.

Tappe, A.; Rho, J.; Boersma, C.; Micelotta, E. R.

2012-08-01

312

[FeII] Narrow Band Imaging of Supernova Remnants in the Magellanic Clouds  

NASA Astrophysics Data System (ADS)

Optical, radio and X-ray emission from supernova remnants (SNRs) has been used extensively to study the properties of SNRs, and as such, much is known about their general characteristics in these wavebands. However, surprisingly little work has been done in the near infrared. The early work of Oliva et al. (1989, A&A, 214, 307) suggested that SNRs are generally bright in the emission of [FeII], although this conclusion was based upon observations of only a few very bright SNRs. In order to better define the general characteristics of the [FeII] emission of SNRs, we have undertaken a survey of 35 SNRs in the Magellanic Clouds. These represent a well defined sample with a large range of intrinsic properties, all at the same distance. We present [FeII] fluxes of 1.64mu m emission and discuss correlations of SNR properties observed at other wavelengths with the [FeII] flux. In addition, we discuss the feasibility of using [FeII] flux as an indicator of supernova rates in distant galaxies.

Tavarez, M.; Smith, R. C.; Elston, R.

1996-12-01

313

MOLECULAR CLOUDS AS A PROBE OF COSMIC-RAY ACCELERATION IN A SUPERNOVA REMNANT  

SciTech Connect

We study cosmic-ray acceleration in a supernova remnant (SNR) and the escape from it. We model nonthermal particle and photon spectra for the hidden SNR in the open cluster Westerlund 2, and the old-age mixed-morphology SNR W 28. We assume that the SNR shock propagates in a low-density cavity, which is created and heated through the activities of the progenitor stars and/or previous supernova explosions. We indicate that the diffusion coefficient for cosmic rays around the SNRs is less than approx1% of that away from them. We compare our predictions with the gamma-ray spectra of molecular clouds illuminated by the cosmic rays (Fermi and H.E.S.S.). We found that the spectral indices of the particles are approx2.3. This may be because the particles were accelerated at the end of the Sedov phase, and because energy-dependent escape and propagation of particles did not much affect the spectrum.

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

2009-12-20

314

Changes in the optical remnant of Kepler's supernova during the period 1942-1989  

SciTech Connect

Images of the optical nebulosity associated with Kepler's supernova have been obtained at the Mount Wilson Observatory in 1941-1943, at the Palomar Observatory in 1950-1983, and on La Silla in 1989. These data have been used to study the luminosity evolution of individual knots and the expansion and translation of the optical remnant of Kepler's supernova of 1604. From the study of the motions of 50 long-lived knots, expansion is {minus}0.623 + or {minus} 0.045 arcsec/century, translation is 0.484 + or {minus} 0.049 arcsec/century, and expansion time scale of 32,000 + or {minus} 12,000 yr. For an assumed distance of 4.5 kpc the centroid of the nebulosity tangential velocity is 117 + or {minus} 10 km/s to the W and 105 + or {minus} 11 km/s to the N. By combining astrometric and spectroscopic information, a space velocity of 278 + or {minus} 12 km/s is estimated. This indicates that the progenitor of SN 1604 was a high-velocity object. It could have been either a Population II star or a massive high-velocity runaway star. 30 refs.

Bandiera, R.; Van den bergh, S. (Arcetri, Osservatorio Astrofisico, Florence (Italy) Dominion Astrophysical Observatory, Victoria (Canada))

1991-06-01

315

Deep optical observations of the supernova remnant G 78.2+2.1  

NASA Astrophysics Data System (ADS)

The wide-field covered by the supernova remnant G 78.2+2.1 was observed in the optical emission lines of H?+[N II] S II and O III. The flux calibrated images reveal several H II regions in the field which dominate the optical emission but we were able to identify possible areas of shock-heated emission through the H?+[N II] and S II images. These are mainly found to the north-east of gamma Cygni as well as in the south and the morphology of the detected emission is patchy and diffuse. A few patchy structures are also detected in the medium ionization line image of [O III]. Long-slit spectra taken at one of the candidate positions verify that we have detected radiation from shock-heated gas (S II/H? = 0.6). The estimated shock velocity lies below 100 km s-1, while the measured electron density of 700 cm-3 implies preshock cloud densities of 20 cm-3. High resolution maps in the infrared show that the optical emission, which may be associated with G 78.2+2.1, lies in areas relatively free of infrared emission. The interstellar extinction measured through the optical spectra is compatible with current estimates of the distance to the remnant. The optical data are in agreement with the explosion energy and interstellar medium density estimated from the X-ray data suggesting that the remnant is still in the adiabatic phase of its evolution. A second set of spectra taken in the north-west suggests that we are probably dealing with a foreground H II region.

Mavromatakis, F.

2003-09-01

316

TeV Gamma Rays and Cosmic-Ray Acceleration in Supernova Remnants  

NASA Astrophysics Data System (ADS)

If supernova remnants (SNRs) are the site of cosmic-ray acceleration, the associated nuclear interactions should result in an observable flux of ?^0-decay ?-rays for the nearest SNRs. Measurements of the TeV ?-ray flux from nearby, radio-bright SNRs have been made with the Whipple imaging air Cherenkov telescope but reveal no significant emission (Buckley et al. 1998). Three of these SNRs (IC443, ?-Cygni and W44) are spatially coincident with low-latitude unidentified sources detected with the Energetic Gamma-Ray Experiment Telescope (EGRET). If the EGRET ?-ray fluxes result from cosmic-ray interactions, then the EGRET and Whipple data are found to be collectively inconsistent with a cosmic-ray source spectrum flatter than ~ E-2.4. The Whipple upper limits for IC443 and ?-Cygni are also inconsistent with a priori predictions if these remnants are indeed expanding into regions where the average density of the interstellar medium is enhanced by the presence of molecular clouds. Recent observations of nonthermal X-rays in the limbs of a number of shell-type SNRs (including IC443, SN 1006 and Cassiopeia A) signify the presence of very high energy electrons (E>10 TeV) in the vicinity of SNR shells. More Recently, the CANGAROO atmospheric Cherenkov telescope has detected significant TeV emission from the remnant SN 1006 (Tanimori et al. 1998), but in this case the TeV emission most probably arises from inverse-Compton scattering by energetic electrons. Despite the growing body of evidence for shock acceleration of electrons in SNRs, there is still no direct evidence pointing to the source of cosmic ray nuclei and the data are beginning to require a modification of the simplest models of shock acceleration and energy dependent propagation of cosmic rays.

Buckley, James H.

1998-04-01

317

Asymmetric Neutrino Emission in Quark Matter and Pulsar Kicks  

Microsoft Academic Search

We derive conditions for an asymmetric neutrino emission of hot neutron stars with quark matter as a source for the observed large kick velocities of pulsars out of supernova remnants. We work out in detail the constraints for the initial temperature, the strength of the magnetic field and the electron chemical potential in the quark matter core. Also the neutrino

I. Sagert; J. Schaffner-Bielich

2008-01-01

318

The X-ray observational satellite XMM, its spectrometer, and observations of supernova remnants  

NASA Astrophysics Data System (ADS)

This thesis centers on the reflection grating spectrometer of the XMM observatory: its design, calibration, and impact on the field of X-ray spectroscopy within the context of the spectrometers of the upcoming generation of X-ray observatories, including Chandra and ASTRO-E. The context of experimental X-ray spectroscopy is illustrated through the detailed descriptions of the components comprising each of the new spectrometers and how the components function and interact. Their operational capabilities are illustrated with simulated results of their observations of X-ray sources-all supernova remnants-that highlight each observatory's specialties. XMM's spectrometer design is based on an array of reflection gratings which disperse X-rays to a set of CCD detectors aligned along the dispersion axis in an inverted Rowland circle. An extension to existing scattering theory was developed and experimentally verified in order to characterize the contribution to the line spread function from grating scatter due to surface roughness. This theory predicts the angular redistribution of small angle scattering of light incident on a reflection grating as a function of intrinsic properties of the grating surface-the root mean square height and correlation length of deviations from the ideal surface-and properties of the scattering geometry-incident angle, exit angle, and wavelength. The predictions of the theory were tested and verified in a long beam X-ray testing facility at Columbia's Nevis Labs. The calibration of the two grating arrays was performed at the Panter X-ray testing facility near Munich, Germany. The comprehensive results of this extensive calibration are presented. The physical model of the arrays was based on the ideal Rowland circle design, and also included deviations from ideal positionings, manufacturing tolerances, and assembly of gratings into the array, as well as its operating processes, principally grating scatter. This model was entirely constrained, with no free parameters (with one noted exception) before the calibration campaigns, and was found to be accurate to within Panter's experimental capabilities. Finally, a new analysis of the galactic supernova remnant, W49B, observed by the ASCA observatory in 1993, is presented. The results of this analysis suggest that the morphology of W49B, whose spatial profile was previously not well understood, is clearly shell-like. It is likely very similar to Tycho's remnant in shape, and is of Type Ia as well.

Spodek, Joshua David

319

INDUCED ROTATION IN THREE-DIMENSIONAL SIMULATIONS OF CORE-COLLAPSE SUPERNOVAE: IMPLICATIONS FOR PULSAR SPINS  

SciTech Connect

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 simple neutrino heating and cooling scheme, we present a numerical study of the evolution in three dimensions of the rotational profile of a supernova core from collapse, through bounce and shock stagnation, to delayed explosion. By the end of our simulation ({approx}420 ms after core bounce), we do not witness significant spin-up of the proto-neutron star core left behind. However, we do see the development before the explosion of strong differential rotation in the turbulent gain region between the core and stalled shock. Shells in this region acquire high spin rates that reach {approx}150 Hz, but this region contains too little mass and angular momentum to translate, even if left behind, into rapid rotation for the full neutron star. We also find that much of the induced angular momentum is likely to be ejected in the explosion, and moreover that even if the optimal amount of induced angular momentum is retained in the core, the resulting spin period is likely to be quite modest. Nevertheless, induced periods of seconds are possible.

Rantsiou, Emmanouela; Burrows, Adam; Nordhaus, Jason [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Almgren, Ann, E-mail: emmarant@astro.princeton.edu, E-mail: burrows@astro.princeton.edu, E-mail: nordhaus@astro.princeton.edu, E-mail: asalmgren@lbl.gov [Computational Research Division, Lawrence Berkeley National Lab, Berkeley, CA 94720 (United States)

2011-05-01

320

An absence of ex-companion stars in the type Ia supernova remnant SNR 0509-67.5  

NASA Astrophysics Data System (ADS)

A type Ia supernova is thought to begin with the explosion of a white dwarf star. The explosion could be triggered by the merger of two white dwarfs (a `double-degenerate' origin), or by mass transfer from a companion star (the `single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the centre of a known type Ia supernova remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of the supernova observed by Tycho Brahe has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a type Ia supernova 400+/-50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a visual magnitude limit of 26.9 (an absolute magnitude of MV = +8.4) within a region of radius 1.43 arcseconds. (This corresponds to the 3? maximum distance to which a companion could have been `kicked' by the explosion.) This lack of any ex-companion star to deep limits rules out all published single-degenerate models for this supernova. The only remaining possibility is that the progenitor of this particular type Ia supernova was a double-degenerate system.

Schaefer, Bradley E.; Pagnotta, Ashley

2012-01-01

321

Discovery of X-Ray Emission from and Distance to the Supernova Remnant G84.2-0.8  

NASA Astrophysics Data System (ADS)

We analyze X-ray and radio observations of the supernova remnant G84.2-0.8. 1420 MHz atomic hydrogen (H I) line and radio continuum data yield H I absorption spectra and a new H I absorption distance of 5.8-6.2 kpc. Archival X-ray observations from ROSAT and Chandra which cover the area including G84.2-0.8 are analyzed to show extended X-ray emission from G84.2-0.8. Fits to X-ray spectra from Chandra, with the new H I distance of 5.8-6.2 kpc, are used to determine the Sedov parameters of the supernova remnant. G84.2-0.8 is large (16-18 pc radius), middle aged (~9000 yr), expanding in low-density interstellar medium (0.02 cm-3), and consistent with a low explosion energy (0.8-6.5 1050 erg).

Leahy, Denis A.; Green, Kaylie S.

2012-11-01

322

FISICA Integral Field Spectroscopy of the Shocked Iron Gas in the Supernova Remnant G11.2--0.3  

NASA Astrophysics Data System (ADS)

We have recently discovered strong iron line ([Fe II] (lambda)1.644 (mu)m) emission in the young supernova remnant G11.2-0.3. The iron line emission occurs at the south-eastern shell edge of G11.2-0.3, and positionally overlaps with the very strong X-ray and radio emission of the supernova remnant. The iron line emission is most likely caused by the shock acceleration of G11.2-0.3 interacting with the ambient medium. We propose to carry out JH-band integral-field spectroscopy of the two iron line clumps in G11.2-0.3 with FISICA, an image-slicing integral-field unit for FLAMINGOS, which will give us a uniquely comprehensive view of the strong shock acceleration of a SNR.

Moon, Dae-Sik; Eikenberry, Stephen S.; Koo, Bon-Chul; Raines, S. Nicholas; Gruel, Nicolas

2006-02-01

323

High-resolution X-Ray Spectroscopy of the Galactic Supernova Remnant Puppis A with XMM-Newton/RGS  

NASA Astrophysics Data System (ADS)

We present high-resolution X-ray spectra of cloud-shock interaction regions in the eastern and northern rims of the Galactic supernova remnant Puppis A, using the Reflection Grating Spectrometer on board the XMM-Newton satellite. A number of emission lines including K? triplets of He-like N, O, and Ne are clearly resolved for the first time. Intensity ratios of forbidden to resonance lines in the triplets are found to be higher than predictions by thermal emission models having plausible plasma parameters. The anomalous line ratios cannot be reproduced by effects of resonance scattering, recombination, or inner-shell ionization processes, but could be explained by charge-exchange emission that should arise at interfaces between the cold/warm clouds and the hot plasma. Our observations thus provide observational support for charge-exchange X-ray emission in supernova remnants.

Katsuda, Satoru; Tsunemi, Hiroshi; Mori, Koji; Uchida, Hiroyuki; Petre, Robert; Yamada, Shin'ya; Akamatsu, Hiroki; Konami, Saori; Tamagawa, Toru

2012-09-01

324

Radio Emission from a Young Supernova Remnant Interacting with an Interstellar Cloud: MHD Simulation with Relativistic Electrons  

Microsoft Academic Search

We present two-dimensional MHD simulations of the evolution of a young Type\\u000aIa supernova remnant during its interaction with an interstellar cloud of\\u000acomparable size at impact. We include for the first time in such simulations\\u000aexplicit relativistic electron transport, including spectral information using\\u000aa simple but effective scheme that follows their acceleration at shocks and\\u000asubsequent transport. From this

Byung-Il Jun; T. W. Jones

1998-01-01

325

Very high resolution observations of the radio source in the supernova remnant G127.1+0.5  

Microsoft Academic Search

The results of recent very long baseline interferometry of G127.11+0.54 at 10.65 GHz reveal a core dual 'jet' structure. The morphology and physical properties of the compact source are similar to those of SS 433. The combined data from various studies of this object suggest that G127.11+0.54 may be the stellar remnant of the supernova event which also produced the

B. J. Geldzahler; D. B. Shaffer

1982-01-01

326

Using the X-ray Morphologies of Young Supernova Remnants to Constrain Explosion Type, Ejecta Distribution, and Chemical Mixing  

Microsoft Academic Search

Supernova remnants (SNRs) are a complex class of sources, and their\\u000aheterogeneous nature has hindered the characterization of their general\\u000aobservational properties. To overcome this challenge, we use statistical tools\\u000ato analyze the Chandra X-ray images of Galactic and Large Magellanic Cloud\\u000aSNRs. We apply two techniques, a power-ratio method (a multipole expansion) and\\u000awavelet-transform analysis, to measure the global

Laura A. Lopez; Enrico Ramirez-Ruiz; Daniela Huppenkothen; Carles Badenes; David A. Pooley

2010-01-01

327

X-ray and radio images of four supernova remnants with three distinct X-ray signatures  

Microsoft Academic Search

Radio images of Kepler's supernova remnant (SNR) and new X-ray images of the three SNRs--PKS1209-52, W28, and 3C400.2 were investigated. Although all of them are shell-like SNRs at radio wavelengths, there are distinct X-ray signatures among them. New high resolution radio images of Kepler's SNR reveal shell structure which is very similar to that of the X-ray image. Linear polarization

Y. Matsui

1986-01-01

328

Using the X-ray Morphology of Young Supernova Remnants to Constrain Explosion Type, Ejecta Distribution, and Chemical Mixing  

Microsoft Academic Search

Supernova remnants (SNRs) are a complex class of sources, and their heterogeneous nature has hindered the characterization of their general observational properties. To overcome this challenge, in this paper, we use statistical tools to analyze the Chandra X-ray images of Galactic and Large Magellanic Cloud SNRs. We apply two techniques, a power-ratio method (a multipole expansion) and wavelet-transform analysis, to

Laura A. Lopez; Enrico Ramirez-Ruiz; Daniela Huppenkothen; Carles Badenes; David A. Pooley

2011-01-01

329

Kinetic theory of cosmic ray and gamma-ray production in supernova remnants expanding into wind bubbles  

Microsoft Academic Search

A kinetic model of particle acceleration in supernova remnants (SNRs) is extended to study the cosmic ray (CR) and associated high-energy gamma -ray production during SN shock propagation through the inhomogeneous circumstellar medium of a progenitor star that emits a wind. The wind forms a low-density bubble surrounded by a swept-up shell of interstellar matter. gamma -rays are produced as

E. G. Berezhko; H. J. Vlk

2000-01-01

330

Ultra-Deep Chandra Observation of Galactic Oxygen-Rich Supernova Remnant G292.0+1.8: The First Images  

NASA Astrophysics Data System (ADS)

We present the first images of Galactic O-rich supernova remnant (SNR) G292.0+1.8 from our ultra-deep 0.5 Msec Chandra observation. The deep Chandra ACIS data cover the entire SNR, revealing all the detailed substructures of the outermost boundary of the blast wave and new metal-rich ejecta features which were not detected by previous Chandra observation that had a 10 times shorter exposure and a small field of view. Our deep Chandra data also discover the spectacular structure of a torus and a jet in the central pulsar wind nebula (PWN), reminiscent of the Crab nebula. Utilizing extremely rich photon statistics, we present high-quality images of O-, Ne-, Mg-, and Si-rich ejecta, dense circumstellar medium produced by the massive progenitor's stellar winds and then shocked by the blast wave, the blast wave shock front propagating into a low-density ambient medium all around the SNR, and the fine-structure of the central PWN.

Park, Sangwook; Burrows, D. N.; Hughes, J. P.; Slane, P. O.; Gaensler, B. M.; Ghavamian, P.

2007-05-01

331

Supernova remnants and candidates detected in the XMM-Newton M 31 large survey  

NASA Astrophysics Data System (ADS)

Context. We present the analysis of supernova remnants (SNRs) and candidates in M 31 identified in the XMM-Newton large programme survey of M 31. Supernova remnants are among the brightest X-ray sources in a galaxy. They are good indicators of the recent star-formation activities of galaxies and the interstellar environment in which they evolve. Aims: By combining the X-ray data of sources in M 31 with optical data as well as optical and radio catalogues, we aim to compile a complete, revised list of SNRs emitting X-rays in M 31 detected with XMM-Newton, study their luminosity and spatial distributions, and understand the X-ray spectra of the brightest SNRs. Methods: We analysed the X-ray spectra of the 12 brightest SNRs and candidates that have been observed with XMM-Newton. Our study of the four brightest sources allowed us to perform a more detailed spectral analysis and compare different models to describe their spectrum. For all M 31 large programme sources, we searched for their optical counterparts in the H?, [S ii], and [O iii] images of the Local Group Galaxy Survey. Results: We confirm 21 X-ray sources as counterparts to known SNRs. In addition, we identify 5 new X-ray sources as X-ray and optically emitting SNRs. Seventeen sources are no longer considered as SNR candidates. We thus create a list of 26 X-ray SNRs and 20 X-ray SNR candidates in M 31 based on their X-ray, optical, and radio emission, which is the most recent complete list of X-ray SNRs in M 31. The brightest SNRs have X-ray luminosities of up to 8 1036 erg s-1 in the 0.35-2.0 keV band. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.Appendices are available in electronic form at http://www.aanda.org

Sasaki, M.; Pietsch, W.; Haberl, F.; Hatzidimitriou, D.; Stiele, H.; Williams, B.; Kong, A.; Kolb, U.

2012-08-01

332

Nonthermal emission properties of the northwestern rim of supernova remnant RX J0852.0-4622  

NASA Astrophysics Data System (ADS)

The supernova remnant (SNR) RX J0852.0-4622 (Vela Jr., G266.6-1.2) is one of the most important SNRs for investigating the acceleration of multi-TeV particles and the origin of Galactic cosmic rays because of its strong synchrotron X-ray and TeV ?-ray emission, which show a shell-like morphology similar to each other. Using the XMM-Newton archival data consisting of multiple pointing observations of the northwestern rim of the remnant, we investigate the spatial properties of the nonthermal X-ray emission as a function of distance from an outer shock wave. All X-ray spectra are well reproduced by an absorbed power-law model above 2 keV. It is found that the spectra show gradual softening from a photon index ? = 2.56 in the rim region to ? = 2.96 in the interior region. We show that this radial profile can be interpreted as a gradual decrease of the cutoff energy of the electron spectrum due to synchrotron cooling. By using a simple spectral evolution model that includes continuous synchrotron losses, the spectral softening can be reproduced with the magnetic field strength in the post-shock flow to less than several tens of ?G. If this is a typical magnetic field in the SNR shell, ?-ray emission would be accounted for by inverse Compton scattering of high-energy electrons that also produce the synchrotron X-ray emission. Future hard X-ray imaging observations with Nustar and ASTRO-H and TeV ?-ray observations with the Cherenkov Telescope Array (CTA) will allow us to explore other possible explanations of the systematic softening of the X-ray spectra.

Kishishita, T.; Hiraga, J.; Uchiyama, Y.

2013-03-01

333

3D deflagration simulations leaving bound remnants: a model for 2002cx-like Type Ia supernovae  

NASA Astrophysics Data System (ADS)

2002cx-like supernovae are a sub-class of sub-luminous Type Ia supernovae (SNe). Their light curves and spectra are characterized by distinct features that indicate strong mixing of the explosion ejecta. Pure turbulent deflagrations have been shown to produce such mixed ejecta. Here, we present hydrodynamics, nucleosynthesis and radiative-transfer calculations for a 3D full-star deflagration of a Chandrasekhar-mass white dwarf. Our model is able to reproduce the characteristic observational features of SN 2005hk (a prototypical 2002cx-like supernova), not only in the optical, but also in the near-infrared. For that purpose we present, for the first time, five near-infrared spectra of SN 2005hk from -0.2 to 26.6 d with respect to B-band maximum. Since our model burns only small parts of the initial white dwarf, it fails to completely unbind the white dwarf and leaves behind a bound remnant of 1.03 M? - consisting mainly of unburned carbon and oxygen, but also enriched by some amount of intermediate-mass and iron-group elements from the explosion products that fall back on the remnant. We discuss possibilities for detecting this bound remnant and how it might influence the late-time observables of 2002cx-like SNe.

Kromer, M.; Fink, M.; Stanishev, V.; Taubenberger, S.; Ciaraldi-Schoolman, F.; Pakmor, R.; Rpke, F. K.; Ruiter, A. J.; Seitenzahl, I. R.; Sim, S. A.; Blanc, G.; Elias-Rosa, N.; Hillebrandt, W.

2013-03-01

334

ELEMENTAL ABUNDANCES IN THE POSSIBLE TYPE Ia SUPERNOVA REMNANT G344.7-0.1  

SciTech Connect

Recent studies on the Galactic supernova remnant (SNR) G344.7-0.1 have commonly claimed its origin to be a core-collapse supernova (SN) explosion, based on its highly asymmetric morphology and/or proximity to a star-forming region. In this paper, however, we present an X-ray spectroscopic study of this SNR using Suzaku, which is supportive of a Type Ia origin. Strong K-shell emission from lowly ionized Fe has clearly been detected, and its origin is determined, for the first time, to be the Fe-rich SN ejecta. The abundance pattern is highly consistent with that expected for a somewhat-evolved Type Ia SNR. It is suggested, therefore, that the X-ray point-like source CXOU J170357.8-414302 located at the SNR's geometrical center is not associated with the SNR but is likely to be a foreground object. Our result further indicates that G344.7-0.1 is the first possible Type Ia SNR categorized as a member of the so-called mixed-morphology class. In addition, we have detected emission from He-like Al at {approx}1.6 keV, the first clear detection of this element in the spectrum of an extended X-ray source. The possible enhancement of the Al/Mg abundance ratio from the solar value suggests that the ambient interstellar medium has a relatively high metallicity (not less than 10% of the solar value). We also report the marginal detection of Cr and Mn, although the measured fluxes of these lines have large statistical and systematic uncertainties.

Yamaguchi, H.; Slane, P. O.; Foster, A.; Smith, R. K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Tanaka, M. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Maeda, K. [Institute for the Physics and Mathematics of the Universe, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568 (Japan); Katsuda, S.; Yoshii, R., E-mail: hyamaguchi@head.cfa.harvard.edu [RIKEN - Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)

2012-04-20

335

Identification of Ambient Molecular Clouds Associated with Galactic Supernova Remnant IC 443  

NASA Astrophysics Data System (ADS)

The Galactic supernova remnant (SNR) IC 443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds. However, the ambient molecular clouds with which IC 443 is interacting have not been thoroughly studied and remain poorly understood. Using the Five College Radio Astronomy Observatory 14 m telescope, we obtained fully sampled maps of the ~1 1 region toward IC 443 in the 12CO J = 1-0 and HCO+ J = 1-0 lines. In addition to the previously known molecular clouds in the velocity range v LSR = -6 to -1 km s-1 (-3 km s-1 clouds), our observations reveal two new ambient molecular cloud components: small (~1') bright clouds in v LSR = -8 to -3 km s-1 (SCs) and diffuse clouds in v LSR = +3 to +10 km s-1 (+5 km s-1 clouds). Our data also reveal the detailed kinematics of the shocked molecular gas in IC 443 however, the focus of this paper is the physical relationship between the shocked clumps and the ambient cloud components. We find strong evidence that the SCs are associated with the shocked clumps. This is supported by the positional coincidence of the SCs with shocked clumps and other tracers of shocks. Furthermore, the kinematic features of some shocked clumps suggest that these are the ablated material from the SCs upon the impact of the SNR shock. The SCs are interpreted as dense cores of parental molecular clouds that survived the destruction by the pre-supernova evolution of the progenitor star or its nearby stars. We propose that the expanding SNR shock is now impacting some of the remaining cores and the gas is being ablated and accelerated, producing the shocked molecular gas. The morphology of the +5 km s-1 clouds suggests an association with IC 443. On the other hand, the -3 km s-1 clouds show no evidence for interaction.

Lee, Jae-Joon; Koo, Bon-Chul; Snell, Ronald L.; Yun, Min S.; Heyer, Mark H.; Burton, Michael G.

2012-04-01

336

Nonthermal Radiation from Supernova Remnants: Effects of Magnetic Field Amplification and Particle Escape  

NASA Astrophysics Data System (ADS)

We explore nonlinear effects of wave-particle interactions on the diffusive shock acceleration (DSA) process in Type Ia-like supernova remnant (SNR) blast waves by implementing phenomenological models for magnetic field amplification (MFA), Alfvnic drift, and particle escape in time-dependent numerical simulations of nonlinear DSA. For typical SNR parameters, the cosmic-ray (CR) protons can be accelerated to PeV energies only if the region of amplified field ahead of the shock is extensive enough to contain the diffusion lengths of the particles of interest. Even with the help of Alfvnic drift, it remains somewhat challenging to construct a nonlinear DSA model for SNRs in which of the order of 10% of the supernova explosion energy is converted into CR energy and the magnetic field is amplified by a factor of 10 or so in the shock precursor, while, at the same time, the energy spectrum of PeV protons is steeper than E 2. To explore the influence of these physical effects on observed SNR emission, we also compute the resulting radio-to-gamma-ray spectra. Nonthermal emission spectra, especially in X-ray and gamma-ray bands, depend on the time-dependent evolution of the CR injection process, MFA, and particle escape, as well as the shock dynamic evolution. This result comes from the fact that the high-energy end of the CR spectrum is composed of particles that are injected in the very early stages of the blast wave evolution. Thus, it is crucial to better understand the plasma wave-particle interactions associated with collisionless shocks in detailed modeling of nonthermal radiation from SNRs.

Kang, Hyesung; Jones, T. W.; Edmon, Paul P.

2013-11-01

337

Supernova remnants as a probe of dust grains in the interstellar medium  

NASA Astrophysics Data System (ADS)

Interstellar dust grains play a crucial role in the evolution of the galactic interstellar medium (ISM). Despite its importance, however, dust remains poorly understood in terms of its origin, composition, and abundance throughout the universe. Supernova remnants (SNRs) provide a laboratory for studying the evolution of dust grains, as they are one of the only environments in the universe where it is possible to observe grains being both created and destroyed. SNRs exhibit collisionally heated dust, allowing dust to serve as a diagnostic both for grain physics and for the plasma conditions in the SNR. I present theoretical models of collisionally heated dust which calculate grain emission as well as destruction rates. In these models, I incorporate physics such as nonthermal sputtering caused by grain motions through the gas, a more realistic approach to sputtering for small grains, and arbitrary grain compositions porous and composite grains. I apply these models to infrared and X-ray observations of Kepler's supernova and the Cygnus Loop in the galaxy, and SNRs 0509-67.5, 0519-69.0, and 0540-69.3 in the LMC. X-ray observations characterize the hot plasma while IR observations constrain grain properties and destruction rates. Such a multi-wavelength approach is crucial for a complete understanding of gas and dust interaction and evolution. Modeling of both X-ray and IR spectra allows disentangling of parameters such as pre and postshock gas density, as well as swept-up masses of gas and dust, and can provide constraints on the shock compression ratio. Observations also show that the dust-to-gas mass ratio in the ISM is lower by a factor of several than what is inferred by extinction studies of starlight. Future observatories, such as the James Webb Space Telescope and the International X-ray Observatory, will allow testing of models far beyond what is possible now.

Williams, Brian J.

2010-10-01

338

Kinematics of Shocked Molecular Gas Adjacent to the Supernova Remnant W44  

NASA Astrophysics Data System (ADS)

We mapped molecular gas toward the supernova remnant W44 in the HCO+ J = 1-0 line with the Nobeyama Radio Observatory 45 m telescope and in the CO J = 3-2 line with the Atacama Submillimeter Telescope Experiment 10 m telescope. High-velocity emission wings were detected in both lines over the area where the radio shell of W44 overlaps with the molecular cloud in the plane of the sky. We found that the average velocity distributions of the wing emission can be fit by a uniform expansion model. The best-fit expansion velocities are 12.2 0.3 km s1 and 13.2 0.2 km s1 in HCO+ and CO, respectively. The non-wing CO J = 3-2 component is also fit by the same model with an expansion velocity of 4.7 0.1 km s1. This component might be dominated by a post-shock higher-density region where the shock velocity had slowed down. The kinetic energy of the shocked molecular gas is estimated to be (3.5 1.3) 1049 erg. Adding this and the energy of the previously identified H I shell, we conclude that (1.2 0.2) 1050 erg has been converted into gas kinetic energy from the initial baryonic energy of the W44 supernova. We also found ultra-high-velocity CO J = 3-2 wing emission with a velocity width of ~100 km s1 at (l, b) = (+34.73, 0.47). The origin of this extremely high velocity wing is a mystery.

Sashida, Tomoro; Oka, Tomoharu; Tanaka, Kunihiko; Aono, Kazuya; Matsumura, Shinji; Nagai, Makoto; Seta, Masumichi

2013-09-01

339

Pulsars Everywhere{exclamation_point} A Galactic EGRET Source Retrospective  

SciTech Connect

At the end of the EGRET mission, the only firmly identified sources of GeV emission in our Galaxy were a handful of young pulsars and a solar flare. With the recent launch of AGILE and the imminent launch of GLAST, the sources that EGRET saw will again be studied in {gamma}-rays. We review the multiwavelength observations of the error boxes of Galactic EGRET sources to see what types of sources this new generation of {gamma}-ray telescopes will be studying. I note that most, if not all, of the sources seem to be related to pulsars. Several are probably radio pulsars not known during the time of EGRET. Others are radio-quiet pulsars like Geminga. Still others are probably the product of a pulsar wind interacting with a dense environment. The rest seem to be coincident with things associated with the birth of pulsars i.e. supernova remnants, molecular clouds, and massive star associations.

Roberts, Mallory S. E. [Eureka Scientific, Inc. (United States)

2008-02-27

340

Escaping the accelerator: how, when and in what numbers do cosmic rays get out of supernova remnants?  

NASA Astrophysics Data System (ADS)

The escape of charged particles accelerated by diffusive shock acceleration from supernova remnants is shown to be a more complex process than normally appreciated. Using a box model it is shown that the high-energy end of the spectrum can exhibit spectral breaks even with no formal escape as a result of geometrical dilution and changing time-scales. It is pointed out that the bulk of the cosmic ray particles at lower energies must be produced and released in the late stages of the remnant's evolution, whereas the high-energy particles are produced early on; this may explain recent observations of slight compositional variations with energy. Escape resulting from ion-neutral friction in dense and partially ionized media is discussed briefly and some comments made on the use of the so-called free-escape boundary conditions. Finally, estimates are made of the total production spectrum integrated over the life of the remnant.

Drury, L. O'c.

2011-08-01

341

Fermi-LAT Discovery of GeV Gamma-ray Emission from the Young Supernova Remnant Cassiopeia A  

SciTech Connect

We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope. These observations reveal a source with no discernible spatial extension detected at a significance level of 12.2{sigma} above 500 MeV at a location that is consistent with the position of the remnant of the supernova explosion that occurred around 1680 in the Cassiopeia constellation - Cassiopeia A. The gamma-ray flux and spectral shape of the source are consistent with a scenario in which the gamma-ray emission originates from relativistic particles accelerated in the shell of this remnant. The total content of cosmic rays (electrons and protons) accelerated in Cas A can be estimated as W{sub CR} {approx_equal} (1-4) x 10{sup 49} erg thanks to the well-known density in the remnant assuming that the observed gamma-ray originates in the SNR shell(s). The magnetic field in the radio-emitting plasma can be robustly constrained as B {ge} 0.1 mG, providing new evidence of the magnetic field amplification at the forward shock and the strong field in the shocked ejecta.

Abdo, A.A.

2011-08-19

342

Observation of soft X-ray emission from the supernova remnant G18.95 - 1.1  

NASA Astrophysics Data System (ADS)

Soft X-ray emission has been detected from the supernova remnant G18.95 - 1.1 during the Rosat all-sky survey. The X-ray remnant appears as a partial shell of about 33 arcmin diameter with some central enhancement. The X-ray spectrum has been modeled with a thermal line spectrum of kT = 0.434 keV and interstellar absorption equivalent to N(H) = 3.4 x 10 to the 21st/sq cm. The value of N(H) is consistent with a distance of the source of 2 kpc, which has been dervied earlier from H I-21-cm line measurements. At this distance the total luminosity is about 1.3 x 10 to the 34th erg/s between 0.1 and 2.4 keV. The Sedov analysis shows that the progenitor star exploded about 2000 - 6000 years ago, and that the remnant is expanding into a low-density medium. Arguments are given that the low density did not pre-exist but was possibly created by the stellar wind of the progenitor star. Based on radio observations G18.95 - 1.1 has been suggested to be one of the rare examples of composite supernova remnants. The present X-ray observations provide only an upper limit for the luminosity of 1.3 x 10 to the 33rd erg/s for a center-filling component.

Aschenbach, B.; Brinkmann, W.; Pfeffermann, E.; Fuerst, E.; Reich, W.

1991-06-01

343

CHANDRA IMAGING AND SPECTROSCOPY OF THE EASTERN XA REGION OF THE CYGNUS LOOP SUPERNOVA REMNANT  

SciTech Connect

The XA region of the Cygnus Loop is a bright knot of X-ray emission on the eastern edge of the supernova remnant. The emission results from the interaction of the supernova blast wave with density enhancements at the edge of a precursor formed cavity. However, this interaction is complex given the irregular morphology of the cavity wall. To study the nature and origin of the X-ray emission, we use high spatial resolution images from Chandra. We extract spectra from these images to analyze the physical conditions of the plasma. Our goal is to probe the density of various regions to form a picture of the cavity wall and characterize the interaction between this supernova and the local interstellar medium. We find that a series of regions along the edge of the X-ray emission appears to trace out the location of the cavity wall. The best-fit plasma models result in two temperature component equilibrium models for each region. The low-temperature components have densities that are an order of magnitude higher than the high-temperature components. The high-density plasma may exist in the cavity wall where it equilibrates rapidly and cools efficiently. The low-density plasma is interior to the enhancement and heated further by a reverse shock from the wall. Calculations of shock velocities and timescales since shock heating are consistent with this interpretation. Furthermore, we find a bright knot of emission indicative of a discrete interaction of the blast wave with a high-density cloud in the cavity wall with a size scale {approx}0.1 pc. Aside from this, other extractions made interior to the X-ray edge are confused by line-of-sight projection of various components. Some of these regions show evidence of detecting the cavity wall but their location makes the interpretation difficult. In general, the softer plasmas are well fit at temperatures (kT){approx} 0.11 keV, with harder plasmas at temperatures of (kT){approx} 0.27 keV. All regions displayed consistent metal depletions most notably in N, O, and Ne at an average of 0.54, 0.55, and 0.36 times solar, respectively.

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

2011-04-01

344

X-ray And FUSE Observations Of The SMC Supernova Remnant 1E0102.2-7219 (E0102)  

NASA Astrophysics Data System (ADS)

The Magellanic Cloud supernova remnants provide a sample with relatively well constrained distances, yet with enough angular scale to allow spatially resolved X-ray studies with XMM-Newton and particularly with Chandra. The O-rich supernova remnant 1E0102.2-7219 (or E0102) in the Small Magellanic Cloud is notable for being extremely bright in X-rays, and strongly dominated by He-like and H-like lines of O and Ne. The remnant, with a diameter of approximately 3/4', has been repeatedly observed by Chandra and XMM-Newton as part of their calibration programs. The deep Chandra dataset allows the morphology to be examined in considerable detail. In addition, the low absorption column allows studies in the far ultraviolet. We have observed the remnant with FUSE using the 20"x4" MDRS slit at three positions around the X-ray bright ring. The remnant is detected in broad O VI emission line components. The high spectral resolution of FUSE allows extraction of velocity information which is compared to values obtained from Chandra X-ray grating spectra. The FUSE data, together with the X-ray data, provide information on the three adjacent ionization stages O VI, O VII, and O VII, which are used to probe the plasma conditions. In this talk I will summarize results based on analyses of X-ray and FUSE observations of the remnant.This work was supported by NASA/FUSE grant NAG5-12295 and by NASA contract NAS8-03060.

Gaetz, Terrance J.

2006-06-01

345

GAMMA RAYS FROM THE TYCHO SUPERNOVA REMNANT: MULTI-ZONE VERSUS SINGLE-ZONE MODELING  

SciTech Connect

Recent Fermi and VERITAS observations of the prototypical Type Ia supernova remnant (SNR) Tycho have discovered {gamma}-rays with energies E in the range 0.4 GeV {approx}< E {approx}< 10 TeV. Crucial for the theory of Galactic cosmic-ray origin is whether the {gamma}-rays from SNRs are produced by accelerated hadrons (protons and ions) or by relativistic electrons. Here we show that strong constraints on the leptonic model imposed in the framework of the commonly used single-zone model are essentially removed if the analysis of the broadband radiation spectrum of Tycho is done in the two-zone (or, in general, multi-zone) approach, which is likely to apply to every SNR. Importantly, we show that the single-zone approach may underpredict the {gamma}-ray fluxes by an order of magnitude. A hadronic model can, however, also fit the detected {gamma}-ray spectrum. The difference between {gamma}-ray fluxes of hadronic and leptonic origins becomes significant only at {approx}<300 MeV, which could be revealed by spectral measurements of Tycho and other SNRs at these energies.

Atoyan, Armen [Department of Mathematics, Concordia University, 1455 de Maisonneuve Blvd. West, Montreal, Quebec H3G 1M8 (Canada); Dermer, Charles D., E-mail: atoyan@mathstat.concordia.ca, E-mail: charles.dermer@nrl.navy.mil [Code 7653, Naval Research Laboratory, Washington, DC 20375-5352 (United States)

2012-04-20

346

Unraveling the Origin of Overionized Plasma in the Galactic Supernova Remnant W49B  

NASA Astrophysics Data System (ADS)

In this presentation, I present maps of overionized plasma in the Galactic supernova remnant (SNR) W49B based on a recent 220 ks Chandra Advanced CCD Imaging Spectrometer observation. Overionized plasmas (those where ions are stripped of more electrons than they should be for a given electron temperature) have been found recently in several SNRs, and the physical origin of the rapid cooling necessary to produce them remains uncertain. To assess the cooling scenario responsible for overionization, we performed a spatially-resolved spectroscopic analysis of W49B, measuring the elec- tron temperature by modeling the bremsstrahlung continuum and comparing it to the temperature given by the flux ratio of He-like to H-like lines of sulfur, argon, and calcium. Using these results, we find that the west region of W49B is the most overionized, with a gradient of increasing overionization from East to West. As the ejecta expansion is impeded by molecular material in the east but not in the west, our overionization maps suggest the dominant cooling mechanism is adiabatic expansion of the hot plasma instead of thermal conduction. Furthermore, we find calcium has the greatest degree of overionization relative to argon and sulfur; this result arises because calcium has a longer recombination timescale. Thus, we caution that measurement of overionization is dependent on which elements one employs in their line ratio analysis.

Pearson, Sarah; Lopez, L. A.; Ramirez-Ruiz, E.; Castro, D.; Yamaguchi, H.; Slane, P. O.; Smith, R. K.

2013-04-01

347

The Suzaku Key Project of the Kepler Supernova Remnant: A Status Report  

NASA Astrophysics Data System (ADS)

The Kepler supernova remnant (SNR) is a historical (SN 1604) Type Ia SNR with a peculiar progenitor that exploded in the ambient medium modified by stellar winds. We detect atomic emission lines from trace ejecta elements Mn and Cr in the Kepler SNR using our initial 100 ks Suzaku observation. The detection of these low abundant metal species produced by incomplete Si-burning in the Type Ia SN provides a unique opportunity to reveal the progenitor's metallicity. We also detect K line emission from the Ni-rich ejecta which was produced in the nuclear statistical equilibrium at the deepest core of the progenitor. As the start of our Suzaku Key Project of the Kepler SNR to place a tight constraint on the progenitor's metallicity, we performed 220 ks background observations to reduce the systematic errors on the Mn and Cr line flux measurements. We report on the refined measurements of the Mn to Cr line flux ratio using our new background data. Our preliminary results suggest an enhanced metallicity (several times the Solar) for the Kepler SNR's progenitor. The completion of our Suzaku Key Project with the upcoming deep Kepler observation will be essential to pin down the suggested high metallicity of the progenitor by significantly reducing the large statistical uncertainties embedded in the current data.

Park, Sangwook; Badenes, C.; Hughes, J. P.; Slane, P. O.; Burrows, D. N.; Mori, K.

2010-02-01

348

The Time-dependent Emission from Molecular Clouds Illuminated by Cosmic Rays Escaped from Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernova Remnants (SNRs) are widely discussed as main sources of Galactic Cosmic Rays (CRs) up to 1015 eV or even higher. The CR spectrum observed at Earth is soft (s>2), and so are the gamma-ray spectra observed from a number of SNRs interacting with molecular clouds (MCs). However, current predictions of non-linear particle acceleration theories favor hard CR spectra. Knowing that the CRs near Earth or illuminating MCs in the vicinity of SNR are actually escaped particles that have undergone diffusion, we study how their spectrum depends on the time-dependent acceleration history of the source. We solve the CR transport equation in test-particle approach, combined with numerical simulations of the hydrodynamical evolution of SNRs. Having previously established the importance for the photon emission of particles accelerated at the reverse shock, we calculate the time-dependent gamma-ray spectra from MCs illuminated by the CRs which escaped nearby SNR, and compare our results with data taken with Fermi and Cherenkov telescopes.

Telezhinsky, Igor; Pohl, M.; Dwarkadas, V.

2011-09-01

349

Very High Energy Gamma Rays from Supernova Remnants and Constraints on the Galactic Interstellar Radiation Field  

SciTech Connect

The large-scale Galactic interstellar radiation field (ISRF) is the result of stellar emission and dust re-processing of starlight. Where the energy density of the ISRF is high (e.g., the Galactic Centre), the dominant {gamma}-ray emission in individual supernova remnants (SNRs), such as G0.9+0.1, may come from inverse Compton (IC) scattering of the ISRF. Several models of the ISRF exist. The most recent one, which has been calculated by us, predicts a significantly higher ISRF than the well used model of Mathis, Mezger, and Panagia [1]. However, comparison with data is limited to local observations. Based on our current estimate of the ISRF we predict the gamma-ray emission in the SNRs G0.9+0.1 and RXJ1713, and pair-production absorption features above 20 TeV in the spectra of G0.9+0.1, J1713-381, and J1634-472. We discuss how GLAST, along with current and future very high energy instruments, may be able to provide upper bounds on the large-scale ISRF.

Porter, T.A.; Moskalenko, I.V.; Strong, A.W.

2007-04-30

350

OPTICAL DISCOVERY OF AN APPARENT GALACTIC SUPERNOVA REMNANT G159.6+7.3  

SciTech Connect

Deep H{alpha} images of portions of a faint 3{sup 0} x 4{sup 0} H{alpha} shell centered at l = 159.{sup 0}6, b = 7.{sup 0}3 seen on the Virginia Tech Spectral Line Survey images revealed the presence of several thin emission filaments along its eastern limb. Low-dispersion optical spectra of two of these filaments covering the wavelength range of 4500-7500 A show narrow H{alpha} line emissions with velocities around -170 {+-} 30 km s{sup -1}. Both the morphology and spectra of these filaments are consistent with a Balmer-dominated shock interpretation and we propose that these optical filaments indicate that the large H{alpha} emission shell is a previously unrecognized supernova remnant (SNR). ROSAT All Sky Survey images indicate the possible presence of extremely faint, diffuse emission from the shell's central region. The shell's location more than 7{sup 0} off the Galactic plane in a region of relatively low interstellar density may account for the lack of any reported associated non-thermal radio emissions. The rare discovery of a Galactic SNR at optical wavelengths suggests that additional high-latitude SNRs may have escaped radio and X-ray detection.

Fesen, Robert A.; Milisavljevic, Dan [6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

2010-11-15

351

A GENERALIZED MODEL OF NONLINEAR DIFFUSIVE SHOCK ACCELERATION COUPLED TO AN EVOLVING SUPERNOVA REMNANT  

SciTech Connect

To better model the efficient production of cosmic rays (CRs) in supernova remnants (SNRs) with the associated coupling between CR production and SNR dynamics, we have generalized an existing cr-hydro-NEI code to include the following processes: (1) an explicit calculation of the upstream precursor structure including the position-dependent flow speed, density, temperature, and magnetic field strength; (2) a momentum- and space-dependent CR diffusion coefficient; (3) an explicit calculation of magnetic field amplification; (4) calculation of the maximum CR momentum using the amplified magnetic field; (5) a finite Alfven speed for the particle scattering centers; and (6) the ability to accelerate a superthermal seed population of CRs, as well as the ambient thermal plasma. While a great deal of work has been done modeling SNRs, most work has concentrated on either the continuum emission from relativistic electrons or ions or the thermal emission from the shock heated plasma. Our generalized code combines these elements and describes the interplay between CR production and SNR evolution, including the nonlinear coupling of efficient diffusive shock acceleration, based mainly on the work of P. Blasi and coworkers, and a non-equilibrium ionization (NEI) calculation of thermal X-ray line emission. We believe that our generalized model will provide a consistent modeling platform for SNRs, including those interacting with molecular clouds, and improve the interpretation of current and future observations, including the high-quality spectra expected from Astro-H. SNR RX J1713.7-3946 is modeled as an example.

Lee, Shiu-Hang; Nagataki, Shigehiro [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Ellison, Donald C., E-mail: lee@yukawa.kyoto-u.ac.jp, E-mail: nagataki@yukawa.kyoto-u.ac.jp, E-mail: don_ellison@ncsu.edu [Physics Department, North Carolina State University, Box 8202, Raleigh, NC 27695 (United States)

2012-05-10

352

Magnetic Turbulence Production by Cosmic Rays Drifting Upstream of Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

We present results of two- and three-dimensional Particle-In-Cell simulations of magnetic turbulence production by isotropic cosmic-ray ions drifting upstream of supernova remnant shocks. The studies aim at testing predictions of a strong amplification of short-wavelength nonresonant wave modes and at studying the subsequent evolution of the magnetic turbulence and its backreaction on cosmic ray trajectories. The detailed knowledge of the upstream turbulence properties is crucial to ascertain all aspects of the shock acceleration process-the transport properties of cosmic rays, the shock structure, thermal particle injection and heating processes. An amplification of magnetic field would also facilitate the acceleration of particles beyond the ``knee'' in the cosmic-ray spectrum. We confirm the generation of the turbulent magnetic field due to the drift of cosmic-ray ions in the upstream plasma but find that the amplitude of the turbulence saturates at about ?B/B~1. The backreaction of the magnetic turbulence on the particles leads to an alignment of the bulk-flow velocities of the cosmic rays and the background medium. This is an essential characteristic of cosmic-ray modified shocks: the upstream flow speed is continuously changed by the cosmic rays. The deceleration of the cosmic-ray drift and the simultaneous bulk acceleration of the background plasma account for the saturation of the instability at moderate amplitudes of the magnetic field. A strong magnetic field amplification to amplitudes ?B>>B0 has not been demonstrated yet.

Niemiec, Jacek; Pohl, Martin; Stromal, Thomas; Nishikawa, Ken-Ichi

2008-12-01

353

Violent evolution of supernova remnants as revealed by Chandra and XMM-Newton  

NASA Astrophysics Data System (ADS)

Recent Chandra and XMM-Newton observations have directly revealed evolution of young supernova remnants (SNRs), i.e., expansions and year-scale spectral variations. We show that expansions can be used to infer basic parameters of SNRs such as the age, the distance, and the density: Vela Jr. turns out to be located gtrsim 750 pc away and 1000-3000 yr old, and the ambient density around the northeastern rim of SN1006 is found to be 0.085+0.055-0.035 cm-3. In addition, Chandra confirms a paradoxical difference in expansion rates for Cas A measured in the different wave bands. On the other hand, Chandra-based expansions for Kepler and Tycho are found to disagree with the previous ROSAT/Einstein-based expansions, but be consistent with radio expansions. Year-scale flickering of filaments is discovered in RX J1713.7-3946 and Cas A. It is considered to be possible evidence of extremely fast acceleration/cooling of relativistic electrons in a strongly amplified magnetic field to the level of mG-scale. Also, global flux decline and spectral steepening are found in Cas A, whereas no such spectral variations are detected in SN1006.

Katsuda, S.; Tsunemi, H.

354

Thermal and Nonthermal X-Ray Emission from the Forward Shock in Tycho's Supernova Remnant  

NASA Astrophysics Data System (ADS)

We present Chandra X-ray images of Tycho's supernova remnant that delineate its outer shock as a thin, smooth rim along the straight northeastern edge and most of the circular western half. The images also show that the Si and S ejecta are highly clumpy and have reached near the forward shock at numerous locations. Most of the X-ray spectra that we examine along the rim show evidence of line emission from Si and S ejecta, while the continuum is well represented by either a thermal or a nonthermal model. If the continuum is assumed to be thermal, the electron temperatures at the rim are all similar at about 2 keV, while the ionization ages are very low because of the overall weakness of the line emission. These electron temperatures are substantially below those expected for equilibration of the electron and ion temperatures, assuming shock velocities inferred from radio and X-ray expansion measurements; the electron-to-mean temperature ratios are <~0.1-0.2, indicating that collisionless heating of the electrons at the shock is modest. The nonthermal contribution to these spectra might be important, but cannot be strongly constrained by these data. It could account for as much as half of the flux in the 4-6 keV energy range, based on an extrapolation of the hard X-ray spectrum above 10 keV.

Hwang, Una; Decourchelle, Anne; Holt, Stephen S.; Petre, Robert

2002-12-01

355

Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks  

NASA Astrophysics Data System (ADS)

We describe a semi-analytical approach to non-linear diffusive shock acceleration in the case in which nuclei other than protons are also accelerated. The structure of the shock is determined by the complex interplay of all nuclei, and in turn this shock structure determines the spectra of all components. The magnetic field amplification upstream is described as due to streaming instability of all nuclear species. The amplified magnetic field is then taken into account for its dynamical feedback on the shock structure as well as in terms of the induced modification of the velocity of the scattering centers that enters the particle transport equation. The spectra of accelerated particles are steep enough to be compared with observed cosmic ray spectra only if the magnetic field is sufficiently amplified and the scattering centers have high speed in the frame of the background plasma. We discuss the implications of this generalized approach on the structure of the knee in the all-particle cosmic ray spectrum, which we interpret as due to an increasingly heavier chemical composition above 1015 eV. The effects of a non trivial chemical composition at the sources on the gamma ray emission from a supernova remnant when gamma rays are of hadronic origin are also discussed.

Caprioli, D.; Blasi, P.; Amato, E.

2011-01-01

356

Fermi Large Area Telescope Observations of the Cygnus Loop Supernova Remnant  

SciTech Connect

We present an analysis of the gamma-ray measurements by the Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.

Katagiri, H.; /Ibaraki U., Mito; Tibaldo, L.; /INFN, Padua /Padua U. /Paris U., VI-VII; Ballet, J.; /Paris U., VI-VII; Giordano, F.; /Bari U. /Bari Polytechnic /INFN, Bari; Grenier, I.A.; /Paris U., VI-VII; Porter, T.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Roth, M.; /Washington U., Seattle; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.

2011-11-08

357

A Comparison of X-Ray and Radio Emission from the Supernova Remnant Cassiopeia A  

NASA Astrophysics Data System (ADS)

We compare the radio and soft X-ray brightnesses as a function of position within the young supernova remnant Cassiopeia A. A moderately strong correlation (r = 0.7) was found between the X-ray emission (corrected for interstellar absorption) and radio emission, showing that the thermal and relativistic plasmas occupy the same volumes and are regulated by common underlying parameters. The logarithmic slope of the relationship, ln Sx = 1.2lnSradio + ln k, implies that the variations in brightness are primarily due to path length differences. The X-ray and radio emissivities are both high in the same general locations, but their more detailed relationship is poorly constrained and probably shows significant scatter. The strongest radio and X-ray absorption is found at the western boundary of Cas A. Based on the properties of Cas A and the absorbing molecular cloud, we argue that they are physically interacting. We also compare column densities derived from the Advanced Satellite for Cosmology and Astrophysics with 21 cm H I and 18 cm OH optical depths in the direction of Cas A, in order to provide an independent estimate of interstellar medium properties. We derive an average value for the H I spin temperature of ?40 K and measure the ratio OH/H2, which is nominally larger than previous estimates.

Keohane, Jonathan W.; Rudnick, Lawrence; Anderson, Martha C.

1996-07-01

358

COSMIC-RAY STREAMING FROM SUPERNOVA REMNANTS AND GAMMA-RAY EMISSION FROM NEARBY MOLECULAR CLOUDS  

SciTech Connect

High-energy gamma-ray emission has been detected recently from supernova remnants (SNRs) and their surroundings. The existence of molecular clouds near some of the SNRs suggests that the gamma rays originate predominantly from p-p interactions with cosmic rays (CRs) accelerated at a closeby SNR shock wave. Here we investigate the acceleration of CRs and the gamma-ray production in the cloud self-consistently by taking into account the interactions of the streaming instability and the background turbulence both at the shock front and in the ensuing propagation to the clouds. We focus on the later evolution of SNRs, when the conventional treatment of the streaming instability is valid but the magnetic field is enhanced due to Bell's current instability and/or the dynamo generation of magnetic field in the precursor region. We calculate the time dependence of the maximum energy of the accelerated particles. This result is then used to determine the diffusive flux of the runaway particles escaping the shock region, from which we obtain the gamma spectrum consistent with observations. Finally, we check the self-consistency of our results by comparing the required level of diffusion with the level of the streaming instability attainable in the presence of turbulence damping. The energy range of CRs subject to the streaming instability is able to produce the observed energy spectrum of gamma rays.

Yan Huirong [Kavli Institute of Astronomy and Astrophysics, Peking University, Beijing, 100871 (China); Lazarian, A. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Schlickeiser, R., E-mail: hryan@pku.edu.cn [Institute for Theoretical Physics IV, Ruhr University, Bochum, 44780 (Germany)

2012-02-01

359

The Nature of Gamma-Ray Emission of Tycho's Supernova Remnant  

NASA Astrophysics Data System (ADS)

The nature of the recently detected high-energy and very high-energy ?-ray emission of Tycho's supernova remnant (SNR) is studied. A nonlinear kinetic theory of cosmic-ray (CR) acceleration in SNRs is employed to investigate the properties of Tycho's SNR and their correspondence with the existing experimental data, taking into account that the ambient interstellar medium (ISM) is expected to be clumpy. It is demonstrated that the overall steep ?-ray spectrum observed can be interpreted as the superposition of two spectra produced by the CR proton component in two different ISM phases: the first ?-ray component, extending up to about 1014 eV, originates in the diluted warm ISM, whereas the second component, extending up to 100 GeV, comes from numerous dense, small-scale clouds embedded in this warm ISM. Given the consistency between acceleration theory and the observed properties of the nonthermal emission of Tycho's SNR, very efficient production of nuclear CRs in Tycho's SNR is established. The excess of the GeV ?-ray emission due to the clouds' contribution above the level expected in the case of a purely homogeneous ISM is inevitably expected in the case of Type Ia SNe.

Berezhko, E. G.; Ksenofontov, L. T.; Vlk, H. J.

2013-01-01

360

Submillimeter/millimeter observations of the molecular clouds associated with Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

We have carried out CO J = 2 - 1 and CO J = 3 - 2 observations toward Tycho's supernova remnant (SNR) using the KOSMA 3m-telescope. From these observations, we identified three molecular clouds (MCs) around the SNR. The small cloud in the southwest was discovered for the first time. In the north and east, two MCs (Cloud A and Cloud B) adjacent in space display a bow-shaped morphology, and have broad emission lines, which provide some direct evidences of the SNR-MCs interaction. The MCs are revealed at -69 -59 km s-1, coincident with Tycho's SNR. The MCs associated with Tycho's SNR have a mass of 2.13 103 M?. Position-velocity diagrams show the two clouds to be adjacent in velocity, which means cloud-cloud collision could occur in this region. The maximum value (0.66 0.10) of the integrated CO line intensity ratio (ICO J=3-2/ICO J=2-1) for the three MCs agrees well with the previous measurement of individual Galactic MCs, implying that the SNR shock drove into the MCs. The two MCs have a line intensity ratio gradient. The distribution of the ratio appears to indicate that the shock propagates from the southwest to the northeast.

Xu, Jin-Long; Wang, Jun-Jie; Miller, Martin

2011-05-01

361

Unraveling the Origin of Overionized Plasma in the Galactic Supernova Remnant W49B  

NASA Astrophysics Data System (ADS)

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 is necessary to produce this situation, yet the physical origin of that cooling remains uncertain. To assess the cooling scenario responsible for overionization, in this paper we identify and map the overionized plasma in the Galactic SNR W49B based on a 220 ks Chandra Advanced CCD Imaging Spectrometer observation. We performed a spatially resolved spectroscopic analysis, measuring the electron temperature by modeling the continuum and comparing it to the temperature given by the flux ratio of the He-like and H-like lines of sulfur and argon. Using these results, we find that W49B is overionized in the west, with a gradient of overionization increasing from east to west. As the ejecta expansion is impeded by molecular material in the east but not in the west, our overionization maps suggest the dominant cooling mechanism is adiabatic expansion of the hot plasma.

Lopez, Laura A.; Pearson, Sarah; Ramirez-Ruiz, Enrico; Castro, Daniel; Yamaguchi, Hiroya; Slane, Patrick O.; Smith, Randall K.

2013-11-01

362

?-rays from molecular clouds illuminated by accumulated diffusive protons - II. Interacting supernova remnants  

NASA Astrophysics Data System (ADS)

Recent observations reveal that spectral breaks at GeV are commonly present in Galactic ?-ray supernova remnants (SNRs) interacting with molecular clouds and that most of them have a spectral (E2dF/dE) 'platform' extending from the break to lower energies. In Paper I, we developed an accumulative diffusion model by considering an accumulation of the diffusive protons escaping from the shock front throughout the history of the SNR expansion. In this paper, we improve the model by incorporating the finite volume of molecular clouds, demonstrate the model dependence on particle diffusion parameters and cloud size, and apply it to nine interacting SNRs (W28, W41, W44, W49B, W51C, Cygnus Loop, IC443, CTB 37A and G349.7+0.2). This refined model naturally explains the GeV spectral breaks and, in particular, the 'platforms', together with available TeV data. We find that the index of the diffusion coefficient ? is in the range 0.5-0.7, similar to the Galactic averaged value, and the diffusion coefficient for cosmic rays around the SNRs is essentially two orders of magnitude lower than the Galactic average (? 0.01), which is a good indication for the suppression of cosmic-ray diffusion near SNRs.

Li, Hui; Chen, Yang

2012-04-01

363

Constraints on cosmic-ray efficiency in the supernova remnant RCW 86  

NASA Astrophysics Data System (ADS)

Several young supernova remnants (SNRs) have recently been detected in the high-and very-high energy gamma-ray domains, and the nature of this emission is still hotly debated. We have studied the broadband nonthermal emission from one of these SNRs, namely RCW 86, by analyzing ~40 months of Fermi/LAT data in the high-energy domain, and the archival X-ray data from several instruments. The derived Fermi/LAT upper limits, together with the H.E.S.S. measurements, are incompatible with a standard E-2p hadronic emission arising from p-p interactions, and can only be accommodated by a particle spectrum harder than E-1.8p. In such hadronic scenario, the total energy in hadrons ?CR = ECR/ESN is ~ 0.07 d22.5/ncm-3 (with d2.5?d/2.5kpc and ncm-3?n/1cm-3), and the average magnetic field B must be larger than 50 ?G in order to significantly suppress any leptonic contribution. On the other hand, the interpretation of the gamma-ray emission by inverse Compton scattering reproduces the multi-wavelength data using a reasonable value for B of 15-25 ?G. In this leptonic scenario, we derive a conservative upper limit to ?CR of 0.04 d22.5/ncm-3.

Renaud, M.; Lemoine-Goumard, M.; Vink, J.; Allen, G. E.; Bamba, A.; Giordano, F.; Uchiyama, Y.; Fermi/LAT Collaboration

2012-12-01

364

Gamma Rays from the Tycho Supernova Remnant: Multi-zone versus Single-zone Modeling  

NASA Astrophysics Data System (ADS)

Recent Fermi and VERITAS observations of the prototypical Type Ia supernova remnant (SNR) Tycho have discovered ?-rays with energies E in the range 0.4 GeV <~ E <~ 10 TeV. Crucial for the theory of Galactic cosmic-ray origin is whether the ?-rays from SNRs are produced by accelerated hadrons (protons and ions) or by relativistic electrons. Here we show that strong constraints on the leptonic model imposed in the framework of the commonly used single-zone model are essentially removed if the analysis of the broadband radiation spectrum of Tycho is done in the two-zone (or, in general, multi-zone) approach, which is likely to apply to every SNR. Importantly, we show that the single-zone approach may underpredict the ?-ray fluxes by an order of magnitude. A hadronic model can, however, also fit the detected ?-ray spectrum. The difference between ?-ray fluxes of hadronic and leptonic origins becomes significant only at lsim300 MeV, which could be revealed by spectral measurements of Tycho and other SNRs at these energies.

Atoyan, Armen; Dermer, Charles D.

2012-04-01

365

Nature vs. 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\\u000aand radio-quiet x-ray pulsars which have been rapidly spun-down to slow spin\\u000aperiods clustered in the range 5-12 s. Most of these unusual pulsars also\\u000aappear to be associated with supernova shell remnants (SNRs) with typical ages\\u000a<30 kyr. By examining the sizes of these remnants versus their ages,

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

1999-01-01

366

Secondary cosmic-ray nuclei from supernova remnants and constraints on the propagation parameters  

NASA Astrophysics Data System (ADS)

Context. The secondary-to-primary boron-to-carbon (B/C) ratio is widely used to study the cosmic-ray (CR) propagation processes in the Galaxy. It is usually assumed that secondary nuclei such as Li-Be-B are generated entirely by collisions of heavier CR nuclei with the interstellar medium (ISM). Aims: We study the CR propagation under a scenario where secondary nuclei can also be produced or accelerated by Galactic sources. We consider the processes of hadronic interactions inside supernova remnants (SNRs) and the re-acceleration of background CRs in strong shocks. We investigate their impact in the propagation parameter determination within present and future data. Methods: Analytical calculations are performed in the frameworks of the diffusive shock acceleration theory and the diffusive halo model of CR transport. Statistical analyses are performed to determine the propagation parameters and their uncertainty bounds using existing data on the B/C ratio, as well as the simulated data expected from the AMS-02 experiment. Results: The spectra of Li-Be-B nuclei emitted from SNRs are harder than those due to CR collisions with the ISM. The secondary-to-primary ratios flatten significantly at ~TeV/n energies, both from spallation and re-acceleration in the sources. The two mechanisms are complementary to each other and depend on the properties of the local ISM around the expanding remnants. The secondary production in SNRs is significant for dense background media, n1 ? 1 cm-3, while the amount of re-accelerated CRs is relevant to SNRs expanding into rarefied media, n1 ? 0.1 cm-3. Owing to these effects, the diffusion parameter ? may be underestimated by a factor of ~5-15%. Our estimations indicate that an experiment of the AMS-02 caliber can constrain the key propagation parameters, while breaking the source-transport degeneracy for a wide class of B/C-consistent models. Conclusions: Given the precision of the data expected from ongoing experiments, the SNR production/acceleration of secondary nuclei should be considered, if any, to prevent a possible mis-determination of the CR transport parameters.

Tomassetti, N.; Donato, F.

2012-08-01

367

The Magellan/IMACS Catalog of Optical Supernova Remnant Candidates in M83  

NASA Astrophysics Data System (ADS)

We present a new optical imaging survey of supernova remnants (SNRs) in M83, using data obtained with the Magellan I 6.5 m telescope and IMACS instrument under conditions of excellent seeing. Using the criterion of strong [S II] emission relative to H?, we confirm all but three of the 71 SNR candidates listed in our previous survey, and expand the SNR candidate list to 225 objects, more than tripling the earlier sample. Comparing the optical survey with a new deep X-ray survey of M83 with Chandra, we find that 61 of these SNR candidates have X-ray counterparts. We also identify an additional list of 46 [O III]-selected nebulae for follow-up as potential ejecta-dominated remnants, seven of which have associated X-ray emission that makes them strong candidates. Some of the other [O III]-bright objects could also be normal interstellar medium (ISM) dominated SNRs with shocks fast enough to doubly ionize oxygen, but with H? and [S II] emission faint enough to have been missed. A few of these objects may also be H II regions with abnormally high [O III] emission compared with the majority of M83 H II regions, compact nebulae excited by young Wolf-Rayet stars, or even background active galactic nuclei. The SNR H? luminosity function in M83 is shifted by a factor of ~4.5 times higher than for M33 SNRs, indicative of a higher mean ISM density in M83. We describe the search technique used to identify the SNR candidates and provide basic information and finder charts for the objects. Based on observations made with the 6.5m Magellan Telescopes located at Las Campanas Observatory, and NASA's Chandra X-Ray Observatory. The ground-based observations were obtained through NOAO, which is operated by the Association of Universities for Research in Astronomy, Inc. for the National Science Foundation. NASA's Chandra Observatory is operated by the Smithsonian Astrophysical Observatory under contract No. NAS83060 and the data were obtained through program GO1-12115.

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

2012-11-01

368

IDENTIFICATION OF AMBIENT MOLECULAR CLOUDS ASSOCIATED WITH GALACTIC SUPERNOVA REMNANT IC 443  

SciTech Connect

The Galactic supernova remnant (SNR) IC 443 is one of the most studied core-collapse SNRs for its interaction with molecular clouds. However, the ambient molecular clouds with which IC 443 is interacting have not been thoroughly studied and remain poorly understood. Using the Five College Radio Astronomy Observatory 14 m telescope, we obtained fully sampled maps of the {approx}1 Degree-Sign Multiplication-Sign 1 Degree-Sign region toward IC 443 in the {sup 12}CO J = 1-0 and HCO{sup +} J = 1-0 lines. In addition to the previously known molecular clouds in the velocity range v{sub LSR} = -6 to -1 km s{sup -1} (-3 km s{sup -1} clouds), our observations reveal two new ambient molecular cloud components: small ({approx}1') bright clouds in v{sub LSR} = -8 to -3 km s{sup -1} (SCs) and diffuse clouds in v{sub LSR} = +3 to +10 km s{sup -1} (+5 km s{sup -1} clouds). Our data also reveal the detailed kinematics of the shocked molecular gas in IC 443; however, the focus of this paper is the physical relationship between the shocked clumps and the ambient cloud components. We find strong evidence that the SCs are associated with the shocked clumps. This is supported by the positional coincidence of the SCs with shocked clumps and other tracers of shocks. Furthermore, the kinematic features of some shocked clumps suggest that these are the ablated material from the SCs upon the impact of the SNR shock. The SCs are interpreted as dense cores of parental molecular clouds that survived the destruction by the pre-supernova evolution of the progenitor star or its nearby stars. We propose that the expanding SNR shock is now impacting some of the remaining cores and the gas is being ablated and accelerated, producing the shocked molecular gas. The morphology of the +5 km s{sup -1} clouds suggests an association with IC 443. On the other hand, the -3 km s{sup -1} clouds show no evidence for interaction.

Lee, Jae-Joon [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Koo, Bon-Chul [School of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-742 (Korea, Republic of); Snell, Ronald L.; Yun, Min S.; Heyer, Mark H. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Burton, Michael G., E-mail: leejjoon@kasi.re.kr [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

2012-04-10

369

VLA Observations of NGC 253: Supernova Remnants and H II Regions at 1 Parsec Resolution  

NASA Astrophysics Data System (ADS)

The edge-on starburst galaxy NGC 253 has been imaged with the VLA at wavelengths ranging from 1.3 to 20 cm, with resolutions between 1 and 15 pc. These images reveal a large number of compact radio sources embedded within the diffuse radio structure in the inner 200 pc of the galaxy. We have identified approximately 64 individual compact radio sources in the galaxy. Of the strongest 17 sources, for which the flux densities are high enough to measure spectral indices with moderately low errors, about half have flat spectra and half have steep spectra; this indicates that perhaps half of the individual radio sources are dominated by thermal radio emission from H II regions. Over an 8 yr timescale, few, if any, of the strongest sources have varied in flux density, with limits of 1%--2% yr-1 on the rate of decrease. At the highest resolution of 1 pc, a number of radio sources are beginning to be resolved, and at least 15 different sources can be identified within the innermost 20 pc of the galaxy. Individual radio sources have been explored in more detail. The strongest source, 5.79-39.0 (TH2), assumed to be at the nucleus of the galaxy, has a brightness temperature greater than 20,000 K at 22 GHz and greater than 40,000 K at 15 GHz. It is unresolved at the VLA and may be either an active galactic nucleus or a very compact (nonvariable) supernova remnant. A resolved flat-spectrum source, 5.72-40.1 (TH6), is located ~20 pc to the southwest. It has an apparent size of 2.4 x 1.2 pc and appears to be an H II region similar to the inner part of 30 Doradus, containing approximately 105 M? in stars, as well as ~600 M? of ionized gas. Source counts, the lack of variability, and the lack of new sources imply that the radio supernova rate is no more than 0.3 yr-1, consistent with estimates made in other wave bands.

Ulvestad, James S.; Antonucci, Robert R. J.

1997-10-01

370

Distances of the TeV supernova remnant complex CTB 37 towards the Galactic bar  

NASA Astrophysics Data System (ADS)

Three supernova remnants (SNRs) form the CTB 37 complex: CTB 37A (G348.5+0.1, associated with the TeV ?-ray source HESS J1714-385), CTB 37B (G348.7+0.3, associated with HESS J1713-381 and the magnetar CXOU J171405.7.381031) and G348.5-0.0. We use 21-cm H I absorption measurements to constrain kinematic distances to these SNRs, which have not previously been determined well. We revise the kinematic distance for CTB 37A to be in the range 6.3-9.5 kpc (previously 11.3 kpc) because it is beyond the near 3-kpc arm and in front of the far side of the CO cloud at -145 km s-1 towards l= 348.5. G348.5-0.0 has an H I column density (?6.11021 cm-2) lower than CTB 37A (7.1 1021 cm-2). Also, G348.5-0.0 does not have the major absorption feature at -107 km s-1 that CTB 37A shows. This is caused by the near 3-kpc arm, so G348.5-0.0 is at a distance of ?6.3 kpc. CTB 37B is at a distance of 13.2 kpc (previously 5-9 kpc) based on: (1) it has an absorption feature at -10 5 km s-1 from the far 3-kpc arm, so CTB 37B is behind it; (2) there is absorption at -30 km s-1 but not at -26 km s-1, which yields the distance value; and (3) the H I column density towards CTB 37B (8.3 1021 cm-2) is larger than that towards CTB 37A. In summary, CTB 37A, CTB 37B and G348.5+0.0 are all at different distances and are only by chance nearby each other on the sky. In addition, we conclude that CTB 37A and 37B are not associated with the historical supernova AD 393.

Tian, W. W.; Leahy, D. A.

2012-04-01

371

A Half-Megasecond Chandra Observation of the Oxygen-rich Supernova Remnant G292.0+1.8  

NASA Astrophysics Data System (ADS)

Our Chandra Large Project of the Galactic O-rich SNR G292.0+1.8 is one of the highlights for the core-collapse SNR studies in the 10-yr legacy of Chandra. We review the early results and report on the recent progress on our analysis of a deep 510 ks Chandra observation. G292.0+1.8 is a textbook example of remnants of core-collapse super novae, harboring a pulsar (J1124-5916) and a pulsar wind nebula, the reverse-shocked metal-rich ejecta material, and the shocked circumstellar wind. The X-ray characteristics of the shocked circumstellar wind shows that the progenitor star had experienced a massive mass loss during its late-stage evolution. A highly nonuniform distribution of thermodynamic conditions of the X-ray-emitting ejecta features suggest that the explosion was likely aspherical. We further reveal spectacular substructures of a torus, a jet, and an extended central compact nebula, all associated with the embedded pulsar. The observation shows a consistent picture of late-stage evolution of massive star, where it loses a significant amount of its initial mass as stellar wind and undergoes an aspheric explosion to leave a neutron star with high spatial velocity.

Lee, Jae-Joon; Park, Sangwook; Hughes, John; Slane, Patrick; Gaensler, Bryan; Ghavamian, Parviz; Burrows, David

2009-09-01

372

The electron density structure and kinematics of the supernova remnant N 49  

NASA Astrophysics Data System (ADS)

Context. Supernova remnants commonly display strong internal inhomogeneities in physical properties; however, most of the observational studies found in the literature are limited to integrated data for extragalactic objects or data from very specific parts of the galactic objects. Thus, important information may be lost. Aims: We studied the spatial variation of the electron density and the kinematics of N 49, the brightest supernova remnant in the Large Magellanic Cloud, based on spatial resolve observations sampling the whole object. Methods: We acquired long-slit spectrophotometric data of high signal-to-noise from twelve locations equally spaced in declination. We extracted 1D spectra in the range 5950 to 6750 from 312 different regions each 2.3? 2? in angular size. The electron density was derived from the line ratio [S ii] ?6717/?6731. The radial velocity and velocity dispersion were obtained from the H? profile. Results: The map of the electron density presents a strong gradient with the density increasing from west to east. The densest areas, with Ne ? 2000 cm-3, are found on the east border of the nebula, near but not exactly coinciding with the brightest areas in the optical. The dense area at the south-east border is on the edge of the bright ridge of filaments associated with the peak of the emission from the nebula at different frequencies. However, the dense zone at the north-east borders is in an area of low brightness. From the H? total flux, we estimate a mass of 207 66 M? for N 49. The maps of the radial velocities of the blue and red shifted components of H? and of the velocity dispersion at 3? showed a rough radial symmetry that can be interpreted as the projection effect of a expanding spherical shell. However, the kinematic centre of symmetry is far from the centre of the X-ray or radio images, although it is near the centre of the optical image of N 49. Conclusions: The detected gradient in density confirmed a previous inference based on the decrease in the brightness ratio between the X-ray and radio emission from east and west and is consistent with the presence of a molecular cloud on the south-east border. We were able to fit the radial profile of the near side velocity using a self-similar solution of a blast wave travelling through a non-homogeneous medium characterized by a power-law density distribution. Maps (as FITS files) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A104

Melnik, I. A. C.; Copetti, M. V. F.

2013-05-01

373

Cosmic rays from pulsars and magnetars  

NASA Astrophysics Data System (ADS)

We compare the expected abundance of cosmic ray electrons and positrons from pulsars and magnetars. We assume that the distribution of infant pulsars and magnetars follows that of high-mass stars in the Milky Way and that the production rate of cosmic rays is proportional to the spin-down and magnetic-decay power of pulsars and magnetars, respectively. In combination with primary and secondary cosmic ray leptons from other sources (especially supernova remnants), we find that both magnetars and pulsars can easily account for the observed cosmic ray spectrum, in particular the dip seen by HESS (High-Energy Stereoscopic System) at several TeV and the increase in positron fraction found by PAMELA (Payload for Antimatter Exploration and Light Nuclei Astrophysics).

Heyl, Jeremy S.; Gill, Ramandeep; Hernquist, Lars

2010-07-01

374

Proper motions of H? filaments in the supernova remnant RCW 86  

NASA Astrophysics Data System (ADS)

We present a proper motion study of the eastern shock-region of the supernova remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried out with Very Large Telescope/FOcal Reducer and low dispersion Spectrograph 2 in 2007 and 2010. For both the north-eastern and south-eastern regions, we measure an average proper motion of H? filaments of 0.10 0.02 arcsec yr-1, corresponding to 1200 200 km s-1 at 2.5 kpc. There is substantial variation in the derived proper motions, indicating shock velocities ranging from just below 700 km s-1 to above 2200 km s-1. The optical proper motion is lower than the previously measured X-ray proper motion of north-eastern region. The new measurements are consistent with the previously measured proton temperature of 2.3 0.3 keV, assuming no cosmic ray acceleration. However, within the uncertainties, moderately efficient (<27 per cent) shock acceleration is still possible. The combination of optical proper motion and proton temperature rule out the possibility that RCW 86 has a distance less than 1.5 kpc. The similarity of the proper motions in the north-east and south-east is peculiar, given the different densities and X-ray emission properties of the regions. The north-eastern region has lower densities and the X-ray emission is synchrotron dominated, suggesting that the shock velocities should be higher than in the south-eastern, thermal X-ray dominated, region. A possible solution is that the H? emitting filaments are biased towards denser regions, with lower shock velocities. Alternatively, in the north-east the shock velocity may have decreased rapidly during the past 200 yr, and the X-ray synchrotron emission is an afterglow from a period when the shock velocity was higher.

Helder, E. A.; Vink, J.; Bamba, A.; Bleeker, J. A. M.; Burrows, D. N.; Ghavamian, P.; Yamazaki, R.

2013-10-01

375

Broad Balmer line emission and cosmic ray acceleration efficiency in supernova remnant shocks  

NASA Astrophysics Data System (ADS)

Context. Balmer emission may be a powerful diagnostic tool for testing the paradigm of cosmic ray (CR) acceleration in young supernova remnant (SNR) shocks. The width of the broad Balmer line is a direct indicator of the downstream plasma temperature. In the case of efficient particle acceleration, an appreciable fraction of the total kinetic energy of the plasma is channeled into CRs, therefore the downstream temperature decreases and so does the broad Balmer line width. This width also depends on the level of thermal equilibration between ions and neutral hydrogen atoms in the downstream. Since generally only a few charge exchange (CE) reactions occur before ionization in young SNR shocks, equilibration between ions and neutrals is not reached, and a kinetic description of the neutrals is required to properly compute Balmer emission. Aims: We provide a method for calculating Balmer emission using a self-consistent description of the shock structure in the presence of neutrals and CRs, which also accounts for the non-Maxwellian distribution of neutrals. Methods: We use a recently developed semi-analytical approach, where neutral particles, ionized plasma, accelerated particles, and magnetic fields are all coupled together through the mass, momentum, and energy flux-conservation equations. The distribution of neutrals is obtained from the full Boltzmann equation in velocity space, coupled to Maxwellian ions through ionization and CE processes. The computation is also an improvement over previous work thanks to a better approximation of the atomic interaction rates. Results: We find that for shock speeds ?2500 km s-1, the distribution of broad neutrals never approaches a Maxwellian and its moments differ from those of the ionized component. These differences lead to a smaller FWHM than predicted in previous calculations, where thermalization was assumed. Conclusions: The method presented here provides a realistic estimate of particle acceleration efficiency in Balmer-dominated shocks.

Morlino, G.; Blasi, P.; Bandiera, R.; Amato, E.

2013-10-01

376

A DEDICATED CHANDRA ACIS OBSERVATION OF THE CENTRAL COMPACT OBJECT IN THE CASSIOPEIA A SUPERNOVA REMNANT  

SciTech Connect

We present results of a recent Chandra X-ray Observatory observation of the central compact object (CCO) in the supernova remnant (SNR) Cassiopeia A. This observation was carried out in an instrumental configuration that combines a high spatial resolution with a minimum spectral distortion, and it allowed us to search for pulsations with periods longer than {approx}0.68 s. We found no evidence of extended emission associated with the CCO, nor statistically significant pulsations (the 3{sigma} upper limit on pulsed fraction is about 16%). The fits of the CCO spectrum with the power-law model yield a large photon index, {Gamma} {approx} 5, and a hydrogen column density larger than that obtained from the SNR spectra. The fits with the blackbody model are statistically unacceptable. Better fits are provided by hydrogen neutron star atmosphere models, with the best-fit effective temperature kT{sup {infinity}}{sub eff} {approx} 0.2 keV, but they require a small star's radius, R = 4-5.5 km, and a low mass, M {approx}< 0.8 M{sub sun}. A neutron star cannot have so small radius and mass, but the observed emission might emerge from an atmosphere of a strange quark star. More likely, the CCO could be a neutron star with a nonuniform surface temperature and a low surface magnetic field (the so-called anti-magnetar), similar to three other CCOs for which upper limits on period derivative have been established. The bolometric luminosity, L{sup {infinity}}{sub bol} {approx} 6 x 10{sup 33} erg s{sup -1}, estimated from the fits with the hydrogen atmosphere models is consistent with the standard neutron star cooling for the CCO age of 330 yr. The origin of the surface temperature's nonuniformity remains to be understood; it might be caused by anisotropic heat conduction in the neutron star crust with very strong toroidal magnetic fields.

Pavlov, G. G. [Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Luna, G. J. M., E-mail: pavlov@astro.psu.ed, E-mail: gluna@cfa.harvard.ed [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

2009-09-20

377

The interaction of supernova remnant G357.7+0.3 with the interstellar medium  

NASA Astrophysics Data System (ADS)

The supernova remnant (SNR) G357.7+0.3 appears to have caused considerable shredding of the local interstellar medium (ISM), leading to the formation of multiple cloud fragments having bright rims and cometary structures. We investigate five of these regions using mid-infrared (MIR) imaging and photometry deriving from the Spitzer Space Telescope (SST), as well as photometry deriving from the 2MASS near-infrared all sky survey, the Mid-Course Science Experiment (MSX) and the Multiband Imaging Photometer for Spitzer (MIPSGAL) survey of the Galactic plane. It is noted that two of the rims show evidence for emission by shock-excited H2 transitions, whilst the centres of the clouds also show evidence for dark extinction cores, observed in silhouette against the bright emission rims. Levels of extinction for these cores are determined to be of the order of AV ~ 17-26 mag, whilst densities n(HI) are of the order of ~104 cm-3, and masses in the region of ~40-100 Msolar. It is shown that the wavelength dependence of extinction is probably similar to that of Cardelli et al. and Martin & Whittet, but differs from the MIR extinction trends of Indebetouw et al. The distributions of Class I young stellar objects (YSOs) imply that many of them are physically associated with the clouds, and were likely formed as a result of interaction between the clouds and SN winds. A determination of the spectral energy distributions (SEDs) of these stars, together with 2D radiative transfer modelling of their continua is used to place constraints upon their properties.

Phillips, J. P.; Marquez-Lugo, R. A.

2010-12-01

378

Observational constraints on energetic particle diffusion in young supernovae remnants: amplified magnetic field and maximum energy  

NASA Astrophysics Data System (ADS)

Constraints on the diffusion and acceleration parameters in five young supernova remnants (SNRs) are derived from the observed thickness of their X-ray rims, as limited by the synchrotron losses of the highest energy electrons, assuming uniform and isotropic turbulence. From a joint study of the electrons diffusion and advection in the downstream medium of the shock, it is shown that the magnetic field must be amplified up to values between 250 and 500 ?G in the case of Cas A, Kepler, and Tycho, or 100 ?G in the case of SN 1006 and G347.3-0.5. The diffusion coefficient at the highest electron energy can also be derived from the data, by relating the X-ray energy cutoff to the acceleration timescale. Values typically between 1 and 10 times the Bohm diffusion coefficient are found to be required. We also find interesting constraints on the energy dependence of the diffusion coefficient, by requiring that the diffusion coefficient at the maximum proton energy be not smaller than the Bohm value in the amplified field. This favours diffusion regime between the Kraichnan and the Bohm regime, and rejects turbulence spectrum indices larger than ? 3/2. Finally, the maximum energy of the accelerated particles is found to lay between 1013 and 5 1013 eV for electrons, and around Z 8 1014 eV at most for nuclei (or 2.5 times less if a Bohm diffusion regime is assumed), roughly independently of the compression ratio assumed at the shock. Even by taking advantage of the uncertainties on the measured parameters, it appears very difficult for the considered SNRs in their current stage of evolution to produce protons up to the knee of the cosmic-ray spectrum, at 3 1015 eV, and essentially impossible to accelerate Fe nuclei up to either the ankle at 3 1018 eV or the second knee at 5 1017 eV.

Parizot, E.; Marcowith, A.; Ballet, J.; Gallant, Y. A.

2006-07-01

379

DUST PROCESSING IN SUPERNOVA REMNANTS: SPITZER MIPS SPECTRAL ENERGY DISTRIBUTION AND INFRARED SPECTROGRAPH OBSERVATIONS  

SciTech Connect

We present Spitzer Multiband Imaging Photometer (MIPS) spectral energy distribution (SED) and Infrared Spectrograph (IRS) observations of 14 Galactic supernova remnants (SNRs) previously identified in the GLIMPSE survey. We find evidence for SNR/molecular cloud interaction through detection of [O I] emission, ionic lines, and emission from molecular hydrogen. Through blackbody fitting of the MIPS SEDs we find the large grains to be warm, 29-66 K. The dust emission is modeled using the DUSTEM code and a three-component dust model composed of populations of big grains (BGs), very small grains (VSGs), and polycyclic aromatic hydrocarbons. We find the dust to be moderately heated, typically by 30-100 times the interstellar radiation field. The source of the radiation is likely hydrogen recombination, where the excitation of hydrogen occurred in the shock front. The ratio of VSGs to BGs is found for most of the molecular interacting SNRs to be higher than that found in the plane of the Milky Way, typically by a factor of 2-3. We suggest that dust shattering is responsible for the relative overabundance of small grains, in agreement with the prediction from dust destruction models. However, two of the SNRs are best fitted with a very low abundance of carbon grains to silicate grains and with a very high radiation field. A likely reason for the low abundance of small carbon grains is sputtering. We find evidence for silicate emission at 20 {mu}m in their SEDs, indicating that they are young SNRs based on the strong radiation field necessary to reproduce the observed SEDs.

Andersen, M. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Rho, J.; Reach, W. T. [SOFIA/USRA NASA Ames Research Center, Mail Stop N211-3, Moffett Field, CA 94035 (United States); Hewitt, J. W. [NASA Goddard Space Flight Center, Mail Code 662, Greenbelt, MD 20771 (United States); Bernard, J. P., E-mail: manderse@rssd.esa.int [Centre d' Etude Spatiale des Rayonnements, CNRS, 9 av. du Colonel Roche, BP 4346, F-31028 Toulouse (France)

2011-11-20

380

INFRARED SPECTRAL MAPPING OF SUPERNOVA REMNANTS. I. N63A AND ITS ENVIRONMENT  

SciTech Connect

We present Spitzer Space Telescope spectra of the supernova remnant (SNR) N63A and its native H II region N63 in the Large Magellanic Cloud. We measure nebular fine-structure lines, H{sub 2} lines, and polycyclic aromatic hydrocarbons (PAHs). The lines contribute half of the flux in the Spitzer 24 {mu}m image of N63A shocked lobes, but only {<=}10% elsewhere. The mid-IR flux is largely due to thermal continuum emission from dust in and around N63A plasma. Electron densities are low everywhere; the differences in mid-IR line ratios separate N63A plasma and its high-excitation surroundings from N63A low-excitation optical lobes. We compare the observed line fluxes and ratios within N63A's shocked lobes and plasma with the predictions from models for moderate and fast shocks to constrain pre-shock densities and shock velocities. N63A's photoionized lobe contains a warm photodissociation region in pressure equilibrium with optically ionized gas. We apply a physical dust model to our spectra supplemented by MIPS photometry. We derive the intensity of radiation heating the dust, the mass fraction due to PAHs, and the masses of dust within our sampled regions and of cooler grains in the diffuse interstellar medium. N63A's shocked lobes and plasma contain {approx}0.07 M{sub Sun} of hot grains, comparable to amounts in other SNRs. Within N63A there is {approx}0.7 M{sub Sun} of warm grains exposed to {>=}100 times the intensity of the local interstellar radiation field. Within the regions, 92% of the total dust mass resides in cool grains emitting {<=}27% of their mid-IR luminosity.

Caulet, Adeline [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801-3080 (United States); Williams, Rosa M., E-mail: adel-col@orange.fr [Department of Earth and Space Sciences, Columbus State University, 701 Front Ave., Columbus, GA 31901 (United States)

2012-12-20

381

High-Resolution VLA Imaging of the Supernova Remnant W28 at 328 and 1415 MHZ  

NASA Astrophysics Data System (ADS)

We present new VLA images at 328 and 1415 MHz of the supernova remnant (SNR) W28. The image at 1415 MHz, produced after the combination of 50 separate VLA pointings and the addition of single-dish data, has an angular resolution of 88"48", with an rms noise of 5 mJy beam-1. At 328 MHz, the image has an angular resolution of 97"52" and an rms noise of 14 mJy beam-1. From these observations we reestimated the characteristic parameters of W28: angular diameter 48', flux densities S1415 MHz=246 Jy and S328 MHz=425 Jy, ?1 GHz~1.810-20 W m-2Hz-1 sr-1, and ?=-0.35 (S~??). The radio spectrum has local variations which correlate with total intensity features. The brighter radio filaments have a spectral index systematically flatter than the rest. The comparison of the radio emission with images in other spectral ranges reveal several excellent correlations. We conclude that (1) the encounter of the SNR shock with a molecular cloud to the east of W28 produced enhanced synchrotron and thermal X-ray emission, compression and distortion in the radio shell, H? filaments, and the excitation of many OH (1720 MHz) masers exactly located in the interface between the shock front and the eastern molecular cloud; and (2) the interaction of the shock front moving toward us with molecular gas located in front of it has been responsible for the formation of the bright radio filaments seen in projection in the northern half of W28 and the excitation of more OH masers. Also, excellent radio/H? correspondence is observed toward the northwest of the SNR. The total energy in relativistic particles is estimated in 21047 ergs.

Dubner, G. M.; Velzquez, P. F.; Goss, W. M.; Holdaway, M. A.

2000-10-01

382

2 MASS Near-Infared Imaging of the Supernova Remnant IC443  

NASA Astrophysics Data System (ADS)

We present near-infrared imaging of IC443, covering the entire supernova remnant (50' diameter) from The Two Micron All Sky Survey (2MASS). 2MASS imaging is taken simultaneously in the J (1.25 microns), H (1.65 microns) and K_s (2.17 microns) bands using a 1.3 m telescope with a three-channel camera. The images have 3.5'' spatial resolution with a pixel size of 1''. The bands include lines of P?, [Ni~II] and [Fe~II] for J band, Br10 and [Fe~II] for H band, and Br? and H_2 for K_s band. Emission from IC443 was detected in all 3 bands from most of the optically bright parts of the remnant, revealing a shell-like morphology. This is the first near-infrared image of the northeastern and eastern parts. The color and structure are very different between the northeastern and southern parts. The northeastern shell shows sheet-like filamentary structure, similar to that of optical emission, with J and H band emission equivalently bright, and weak K_s emission. The H flux is higher than the K flux in the northeast; its ratio is similar order of magnitude to that of previously measured infrared spectroscopy from 2 positions. The ratio implies that the H band emission from the northeastern shell is mostly [Fe II] (1.64 microns), and the [Fe II] emission is much stronger than Br?. This contrasts to the ratio of 0.06 observed in H~II regions. The strong [Fe II] line is produced not only by efficient excitation of Fe but also by grain destruction. Most of bright J band emission can be explained by hydrogen line of P? (1.28 microns) when we estimate the expected intensity relative to Br? and H?. In contrast, the south ridge is dominated by K_s band light with knotty structure, and has weak J and H band emission. The shocked H_2 line emission is well known from the sinus ridge produced by an interaction with dense molecular clouds. The large field of view of the 2MASS image shows that the H_2 emission extends to the east and inner shell of northeastern optical emission, which is abutting a molecular cloud shown in CO maps. This emission suggests that the interaction with the molecular clouds extends to the front side of the remnant in the northeast as well as in the southern ridge. We also report ISO LWS observation of [O~I] (63 microns) for 8 positions of the northeast. Strong lines were detected and peaked at the northeastern shell, where 2MASS image showed filametary structure in J and H. We will show results of diagnostics for molecular shocks combining 2MASS and ISO LWS data, discuss cooling in radiative shock, and compare the pre-shock ISM physical conditions between the northeast and south.

Rho, Jeonghee; van Dyk, Schuyler; Jarrett, T.; Roc, C.; Reach, W. T.

383

Pulsar Velocities  

Microsoft Academic Search

Observations of proper motions of single radio pulsars enable the determination of transverse velocities and hence provide a tool for measuring the amount of asymmetry (i. e., the magnitude of the kick velocity vec{w}) in supernovae (SNe). However, single pulsars are thought to originate from both isolated early type stars which explode in a type II SN and from the

Th. M. Tauris

1999-01-01

384

Role of ejecta clumping and back-reaction of accelerated cosmic rays in the evolution of supernova remnants  

NASA Astrophysics Data System (ADS)

The thermal structure of the post-shock region of a young supernova remnant (SNR) is heavily affected by two main physical effects, the back-reaction of accelerated cosmic rays (CRs) and the Rayleigh-Taylor (RT) instabilities developing at the contact discontinuity between the ejecta and the shocked interstellar medium (ISM). Here, we investigate the role played by both physical mechanisms in the evolution of SNRs through detailed 3D MHD modeling. Our model describes the expansion of the remnant through a magnetized ISM, including consistently the initial ejecta clumping and the effects on shock dynamics due to back-reaction of accelerated CRs. We discuss the role of the initial ejecta clumpiness in developing strong instabilities at the contact discontinuity which may extend upstream to the main shock and beyond.

Orlando, S.; Bocchino, F.; Miceli, M.; Petruk, O.; Pumo, M. L.

385

TWO-DIMENSIONAL PARTICLE-IN-CELL SIMULATIONS OF THE NONRESONANT, COSMIC-RAY-DRIVEN INSTABILITY IN SUPERNOVA REMNANT SHOCKS  

SciTech Connect

In supernova remnants, the nonlinear amplification of magnetic fields upstream of collisionless shocks is essential for the acceleration of cosmic rays to the energy of the 'knee' at 10{sup 15.5} eV. A nonresonant instability driven by the cosmic ray current is thought to be responsible for this effect. We perform two-dimensional, particle-in-cell simulations of this instability. We observe an initial growth of circularly polarized nonpropagating magnetic waves as predicted in linear theory. It is demonstrated that in some cases the magnetic energy density in the growing waves can grow to at least 10 times its initial value. We find no evidence of competing modes, nor of significant modification by thermal effects. At late times, we observe saturation of the instability in the simulation, but the mechanism responsible is an artifact of the periodic boundary conditions and has no counterpart in the supernova-shock scenario.

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); Reville, Brian; Kirk, John G. [Max-Planck-Institut fuer Kernphysik, Heidelberg 69029 (Germany)], E-mail: yutaka@vega.ess.sci.osaka-u.ac.jp

2009-06-10

386

DERIVATION OF THE ELECTRON DISTRIBUTION IN SUPERNOVA REMNANT RX J1713.7-3946 VIA A SPECTRAL INVERSION METHOD  

SciTech Connect

We show that the radio, X-ray, and {gamma}-ray spectrum of the supernova remnant RX J1713.7-3946 can be accounted for with the simplest emission model, where all of these emissions are attributed to a population of relativistic electrons interacting with the cosmic microwave background radiation, IR interstellar photons, and a background magnetic field. Using a spectral inversion method, the parent electron distribution and its uncertainties are derived from the observed photon spectrum. These results are independent of the model of particle acceleration and strongly support the leptonic scenario for the TeV emission.

Li Hui; Chen Yang [Department of Astronomy, Nanjing University, Nanjing 210093 (China); Liu Siming [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2011-11-20

387

2 MASS Near-Infrared Imaging of the Supernova Remnant IC443  

NASA Astrophysics Data System (ADS)

We present near-infrared imaging of IC443, covering the entire supernova remnant (50' diameter) from The Two Micron All Sky Survey (2MASS). 2MASS imaging is taken simultaneously in the J (1.25mu m), H (1.65mu m) and K_s (2.17mu m) bands using a 1.3 m telescope with a three-channel camera. The images have 3.5'' spatial resolution with a pixel size of 1''. The bands include lines of Pbeta , [Ni II] and [Fe II] for J band, Br10 and [Fe II] for H band, and Brgamma and H_2 for K_s band. Emission from IC443 was detected in all 3 bands from most of the optically bright parts of the remnant, revealing a shell-like morphology. This is the first near-infrared image of the northeastern and eastern parts. The color and structure are very different between the northeastern and southern parts. The northeastern sh