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1

Pulsar Winds in Supernova Remnants: hydrodynamical simulations  

Microsoft Academic Search

I will consider the interaction of a pulsar wind with its associated supernova remnant by presenting results from (magneto-)hydrodynamical simulations. The pulsar wind blows a bubble (pulsar wind nebula) into the expanding supernova remnant. I will consider the scenario for which the pulsar gains a kick velocity at its birth event. This yields a pulsar wind nebula which is close

E. van der Swaluw

2002-01-01

2

Pulsar Winds in Supernova Remnants: hydrodynamical simulations  

NASA Astrophysics Data System (ADS)

I will consider the interaction of a pulsar wind with its associated supernova remnant by presenting results from (magneto-)hydrodynamical simulations. The pulsar wind blows a bubble (pulsar wind nebula) into the expanding supernova remnant. I will consider the scenario for which the pulsar gains a kick velocity at its birth event. This yields a pulsar wind nebula which is close to the center of the supernova remnant at early stages (~100-1,000 years) and gets excentric at later stages (~1000-10,000 years) of its evolution. Ultimately the pulsar wind will break through the shell of the supernova remnant. The above scenario is investigated in detail by performing (magneto-) hydrodynamical simulations. These results will be presented, where I will put an emphasis on the evolutionary influence of the kick velocity of the pulsar, the reverse shock of the supernova remnant and the toroidal magnetic fields inside the pulsar wind nebula. The results from these simulations show a diversity of morphologies of pulsar wind nebulae, which can be used to get a better understanding of the evolutionary stage of observed composite remnants.

van der Swaluw, E.

3

Rotating Neutron Stars, Pulsars and Supernova Remnants  

Microsoft Academic Search

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

F. Pacini

1968-01-01

4

Pulsar Evolution within a Composite Supernova Remnant  

NASA Astrophysics Data System (ADS)

Supernova remnants have been observed expanding into a non-uniform density ISM. Such expansion creates asymmetry within the remnant, and we attempt to understand how this asymmetric expansion propagates through a system containing an active pulsar wind nebula. We are particularly interested in applying computational methods to such systems in order to recreate and understand the dynamics driving the formation of observed SNRs and their PWNe. We present here a two-dimensional hydrodynamics simulation of a SNR expanding into a uniform density gradient. The remnant contains an active PWN with a translational velocity of approximately 300 km/s which is expanding into freely expanding, unshocked supernova ejecta. We consider, in particular, the reverse-shock interaction state in which the wind nebula is crushed by the asymmetric reverse shock, and investigate the morphology and mixing of thermal and relativistic gas in the context of observed systems including G327.1-1.1.

Kolb, Christopher; Blondin, John M.; Slane, Patrick O.; Temim, Tea

2014-08-01

5

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

Microsoft Academic Search

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

C. F. Kennel; F. V. Coroniti

1984-01-01

6

Pulsar Wind Nebulae in Evolved Supernova Remnants  

Microsoft Academic Search

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

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

2001-01-01

7

Pulsar Wind Nebulae, Space Velocities and Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

2005-01-01

8

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

9

A 143 Millisecond Radio Pulsar in the Supernova Remnant S147  

NASA Astrophysics Data System (ADS)

We report the discovery of a 143 ms pulsar, PSR J0538+2817, in the supernova remnant S147 (G180.0-1.7). The pulsar is located 40' west of the center of S147, well within its evolved, roughly circular radio structure. An upper limit to the pulsar's age of 6 x 105 yr is consistent with the age of the remnant, estimated to be ~(8 x 104)--(2 x 105) yr. A dispersion measure--derived distance to PSR J0538+2817 is ~1.8 kpc, in reasonable agreement with a 0.8--1.6 kpc distance estimate for S147. These data provide sufficient evidence to hypothesize that the two objects are physically related and form a new association between a radio pulsar and an old supernova remnant.

Anderson, S. B.; Cadwell, B. J.; Jacoby, B. A.; Wolszczan, A.; Foster, R. S.; Kramer, M.

1996-09-01

10

News from Supernova Remnants and Pulsar Wind Nebulae in the TeV Band  

NASA Astrophysics Data System (ADS)

VERITAS is an array of four atmospheric Cherenkov telescopes located in Southern Arizona and is sensitive to gamma rays above 100 GeV. Here we highlight recent VERITAS studies of supernova remnants and pulsar wind nebulae. The results provide constraints on competing particle acceleration emission models within these complex environments.

Humensky, Brian

2014-08-01

11

Morphology of supernova remnants  

SciTech Connect

The difference in morphology between filled and shell type supernova remnants is attributed to differences in the activity of the neutron stars left by the supernovae. Pulsar activity leads to centrally concentrated remnants similar to the Crab. Non-activity as a pulsar results in all of the rotational energy loss going into dipole radiation. The pressure of this radiation creates shell-like objects with hollow interiors such as Cas A.

Radhakrishnan, V.; Srinivasan, G.

1981-01-01

12

The Fast and the Furious: Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants  

NASA Astrophysics Data System (ADS)

Online Presentations of 'The Fast and the Furious: Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and Supernova Remnants', a workshop organized by the XMM-Newton Science Operations Centre of the European Space Agency (ESA)

Ness, J.-U.

2013-07-01

13

A candidate gamma-ray pulsar in the supernova remnant CTA 1  

Microsoft Academic Search

We present a detailed analysis of the high-energy gamma-ray source 2EG J0008+7307. The source has a steady flux and a hard spectrum, softening above 2 GeV. The properties of the gamma-ray source are suggestive of emission from a young pulsar in the spatially coincident CTA 1 supernova remnant, which has recently been found to have a non-thermal X-ray plerion. Our

K. T. S. Brazier; O. Reimer; G. Kanbach; A. Carraminana

1998-01-01

14

Chandra Detection of a Pulsar Wind Nebula Associated With Supernova Remnant 3C 396  

NASA Technical Reports Server (NTRS)

We present a 100 ks observation of the Galactic supernova remnant 3C396 (G39.2-0.3) with the Chandra X-Ray Observatory that we compare to a 20cm map of the remnant from the Very Large Array. In the Chandra images, a nonthermal nebula containing an embedded pointlike source is apparent near the center of the remnant which we interpret as a synchrotron pulsar wind nebula surrounding a yet undetected pulsar. From the 2-10 keV spectrum for the nebula (N(sub H) = 5.3 plus or minus 0.9 x 10(exp 22) per square centimeter, GAMMA =1.5 plus or minus 0.3) we derive an unabsorbed x-ray flux of S(sub z)=1.62 x 10(exp -12) erg per square centimeter per second, and from this we estimate the spin-down power of the neutron star to be E(sup dot) = 7.2 x 10(exp 36) ergs per second. The central nebula is morphologically complex, showing bent, extended structure. The radio and X-ray shells of the remnant correlate poorly on large scales, particularly on the eastern half of the remnant, which appears very faint in X-ray images. At both radio and X-ray wavelengths the western half of the remnant is substantially brighter than the east.

Olbert, C. M.; Keohane, J. W.; Arnaud, K. A.; Dyer, K. K.; Reynolds, S. P.; Safi-Harb, S.

2003-01-01

15

Pulsar Wind Nebulae, Space Velocities and Supernova Remnant Associations  

NASA Technical Reports Server (NTRS)

I am pleased to be able to report significant progress in my research relevant to my LTSA grant. This progress I believe is demonstrated by a long list of publications in 2002, as detailed below. I summarize the research results my collaborators and I obtained in 2002. First, my group announced the major discovery of soft-gamma-repeater-like X-ray bursts from the anomalous X-ray pulsars lE-1048.1$-$5937 and lE-2259+586, using the Rossi X-ray Timing Explorer. This result provides an elegant and long-sought-after confirmation that this class of objects and the soft gamma repeaters share a common nature, namely that they are magnetars. Magnetars are a novel manifestation of young neutron stars, quite different from conventional Crab-like radio pulsars. This discovery was made as part of our regular monitoring program, among the goals of which was to detect such outbursts.

2002-01-01

16

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

SciTech Connect

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

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

2009-05-15

17

AN EXTREME PULSAR TAIL PROTRUDING FROM THE FRYING PAN SUPERNOVA REMNANT  

SciTech Connect

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

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

2012-02-10

18

Non-thermal emission in astrophysical environments: From pulsars to supernova remnants  

NASA Astrophysics Data System (ADS)

The study of electromagnetic radiation from distant astrophysical objects provides essential data in understanding physics of these sources. In particular, non-thermal radiation provides great insight into the properties of local environments, particle populations, and emission mechanisms, knowledge which otherwise would remain untapped. Throughout the projects conducted for this dissertation, we modeled certain aspects of observed non-thermal emission from three classes of sources: radio pulsars, pulsar wind nebulae, and supernova remnants. Orbital variation in the double pulsar system PSR J0737-3039A/B can be used to probe the details of the magnetospheric structure of pulsar B. Strongly magnetized wind from pulsar A distorts the magnetosphere of pulsar B in a way similar to the solar wind's distortion of the Earth's magnetosphere. Using the two complimentary models of pulsar B's magnetosphere, adapted from the Earth's magnetosphere models by Dungey and Tsyganenko, we determine the precise location of the coherent radio emission generation region in pulsar B's magnetosphere. This analysis is complemented by modeling the observed evolution of the pulse profiles of B due to geodetic precession. The emission region is located at about 3750 stellar radii and has a horseshoe-like shape centered on the polar magnetic field lines. The best fit angular parameters of the emission region indicate that radio emission is generated on the field lines which, according to the theoretical models, originate close to the poles and carry the maximum current. When considered together, not only do the results of the two models converge, they can explain why the modulation of B's radio emission at A's period is observed only within a certain orbital phase region. We discuss the implications of these results for pulsar magnetospheric models and mechanisms of coherent radio emission generation. We also developed a spatially-resolved, analytic model for the high-energy non-thermal emission from pulsar wind nebulae (PWNe). Theoretically, synchrotron cooling should cause a gradual change in particle spectrum downstream. This effect is indeed observed in the X-ray spectra of The Crab Nebula , 3C 58, and G21.5.0.9. However, current theoretical models of PWNe that only account for the bulk motion in the pulsar outflow overestimate the steepening of the resulted emission spectrum. This implies that there is an additional mechanism of particle transport which would supply energetic particles to the outer layers of the PWN. Our model solves the lack of high-energy electrons in the outer regions of the nebula by taking the diffusion of particles into account. The resulting multi-wavelength spectra exhibits multiple breaks, which is in agreement with observations. Thin non-thermal X-ray filaments are often seen near shock fronts in young supernova remnants (SNRs), often spatially coincident with the high energy gamma-ray emission. The formation of such discrete features is likely influenced by the combined effects of radiative cooling, advection, and diffusion. Spatially-resolved spectral studies of the filaments may, therefore, provide significant insights into the relative importance of main physical processes involved in young SNRs. Using 1 Ms Chandra observation of Cassiopeia A, we perform advection-diffusion modeling of synchrotron emission of filaments to measure the magnetic field, shock obliquity, the diffusion strength and the plasma turbulence level.

Lomiashvili, David

19

ROSAT observations of the unusual supernova remnant CTB 80 containing the pulsar PSR 1951 + 32  

NASA Technical Reports Server (NTRS)

The unusal supernova remnant CTB, 80 containing the 39.5 ms pulsar PSR 1951 + 32, has been observed with the Position Sensitive Proportional Counter (PSPC) and the High Resolution Imager (HRI) aboard ROSAT. The HRI image, centered on the pulsar, is composed of a bright compact core of approximately 1 arcminute radius containing the pulsar and a compact nebula, as well as a diffuse nebula extending approximately 5 arcminutes eastward of the pulsar. The PSPC allowed us to model the spectra of the point source, the compact nebula and the 5 arcminute diffuse nebula. For a power-law spectrum with photon index Gamma approximately 2 and an interstellar column density of N(sub H) approximately 3 x 10(exp 21)/cm(exp 21) the derived luminosities are approximately 2.3 x 10(exp 33) d(sub 2.5)(exp 2) ergs/s from the pointlike source, approximately 3.9 x 10(exp 33) d(sup 2.5)(exp 2) ergs/s from the compact nebula, and approximately 1.8 x 10(exp 33) d(sub 2.5)(exp 2) ergs/s from the 5 arcminutes diffuse nebula. In addition, the 2 deg diameter circular field of view of the PSPC reveals a hard emission feature southeast of the pulsar with a conical geometry extending out to the edge of the detector. The spectrum from this region is well described by a two-temperature Raymond-Smith thermal plasma with an average temperature of approximately 10(exp 7) K and a luminosity of approximately 10(exp 34)d(sub 2.5)(exp 2) ergs/s. Pulsations from the 39.5 ms puslar, PSR 1951 + 32, are detected at the 99% confidence level. The implied pulsed fration is approximately 35% with a complicated energy-dependent behavior. The compact core and the extended diffuse nebula can be explained as synchrotron radiation from the relativistic pulsar wind confined by the ram pressure of the surrounding inhomgeneous medium. The conelike feature detected southeast of PSR 1951 + 32 is consistent with emission from an optically thin SNR in the radiative cooling phase of its evolution.

Safi-Harb, Samar; Ogelman, Hakki; Finley, John P.

1995-01-01

20

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

21

Supernovae and Supernova Remnants.  

National Technical Information Service (NTIS)

A catalogue of 25 supernova remnants is presented. The objects are shown to satisfy a relation between radio surface brightness at 400 Mc/sec and radius with quite small scatter. On the basis of this relation, distances can be determined. The accuracy of ...

A. Poveda L. Woltjer

1967-01-01

22

Progress in multi-waveband observations of supernova remnants  

Microsoft Academic Search

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

Xuejuan Yang; Fangjun Lu; Wenwu Tian

2008-01-01

23

ROSAT HRI Detection of the 16 ms Pulsar PSR J0537-6910 Inside Supernova Remnant N157B  

NASA Astrophysics Data System (ADS)

Based on a deep ROSAT HRI observation, we have detected a pulsed signal in the 0.1-2 keV band from PSR J0537-6910, the recently discovered pulsar associated with the supernova remnant N157B in the Large Magellanic Cloud. The measured pulse period 0.01611548182 s+/-0.02 ns, epoch MJD 50,540.5, gives a revised linear spin-down rate of 5.1271×10-14 s s-1, which is slightly greater than the previously derived value. The narrow pulse shape (FWHM ~ 10% duty cycle) in the ROSAT band resembles those seen in both RXTE and ASCA data (>~2 keV), but there is also marginal evidence for an interpulse. This ROSAT detection enables us to locate the pulsar at R.A.=5h37m47.2s, decl.=-69deg10'23'' (J2000). With its uncertainty ~3", this position coincides with the centroid of a compact X-ray source. But the pulsed emission accounts for only ~10% of the source luminosity of ~2×1036 ergs-1 in the 0.1-2 keV band. These results support our previous suggestions: (1) the pulsar is moving at a high velocity (~103 km s-1) (2) a bow shock, formed around the pulsar, is responsible for most of the X-ray emission from the source; and (3) a collimated outflow from the bow shock region powers a pulsar wind nebula that accounts for an elongated nonthermal radio and X-ray feature to the northwest of the pulsar.

Wang, Q. Daniel; Gotthelf, E. V.

1998-12-01

24

The discovery of PSR J1833-1034 : the pulsar associated with the supernova remnant G21.5-0.9  

NASA Astrophysics Data System (ADS)

We report the discovery of a young pulsar associated with the supernova remnant G21.5-0.9, using the Giant Metrewave Radio Telescope (GMRT) located near Pune, India. Discovered at a frequency of 610 MHz, J1833-1034 has a period of 61.86 ms and a period derivative of 2.0 × 10^{-13}, making it similar to other known young pulsars. The characteristic age of the pulsar is ? 4900 yr, somewhat higher than estimates for the age of the remnant, but not incompatible with it. The pulsar has a spin-down luminosity of 3.3 × 10^{37} erg s^{-1}, which is the second highest amongst all the known Galactic pulsars.

Gupta, Y.; Mitra, D.; Green, D. A.; Acharyya, A.

2005-08-01

25

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

26

Asymmetry in Supernova Remnants  

Microsoft Academic Search

The importance of studies of asymmetry of supernova remnants for various aspects of astronomy is discussed. In particular, its importance for studies in stellar astronomy and interstellar medium is discussed in considerable detail.

M. Tomic

2010-01-01

27

Neutron Stars in Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Slane, Patrick; Kaluzienski, Lou (Technical Monitor)

2002-01-01

28

The Young Core-Collapse Supernova Remnant G11.2-0.3: An Asymmetric Circumstellar Medium and a Variable Pulsar Wind Nebula  

NASA Astrophysics Data System (ADS)

G11.2-0.3 is a young supernova remnant (SNR) that has been suggested to be associated with a historical supernova of 386 AD. In addition to a bright radio and X-ray shell, it contains a pulsar wind nebula (PWN) and a 65 ms pulsar. We present first results from new deep (about 400 ks in duration) Chandra observations from 2013 May and September. Ahead of the main shell, there are a number of outlying X-ray protrusions surrounded by bow shocks, presumably produced by dense ejecta knots. Pronounced spectral variations are seen in thermal X-ray spectra of the main shell, indicating the presence of shocks with a wide range in shock speeds and large spatial variations in intervening absorption. A band of soft X-ray emission is clearly seen at the remnant's center. We interpret this band as a result of the interaction of supernova ejecta with the strongly asymmetric wind produced by a red supergiant SN progenitor shortly before its explosion. We study interstellar absorption in the central region of the remnant, finding high absorption everywhere. This rules out the association of G11.2-0.3 with SN 386. The PWN is dominated by a bright "jet" whose spatial morphology is markedly different between our May and September observations.

Borkowski, Kazimierz J.; Moseby, A.; Reynolds, S. P.

2014-01-01

29

Discovery of a Be/X-ray pulsar binary and associated supernova remnant in the Wing of the Small Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We report on a new Be/X-ray pulsar binary located in the Wing of the Small Magellanic Cloud (SMC). The strong pulsed X-ray source was discovered with the Chandra and XMM-Newton X-ray observatories. The X-ray pulse period of 1062 s is consistently determined from both Chandra and XMM-Newton observations, revealing one of the slowest rotating X-ray pulsars known in the SMC. The optical counterpart of the X-ray source is the emission-line star 2dFS 3831. Its B0-0.5(III)e+ spectral type is determined from VLT-FLAMES and 2dF optical spectroscopy, establishing the system as a Be/X-ray binary (Be-XRB). The hard X-ray spectrum is well fitted by a power law with additional thermal and blackbody components, the latter reminiscent of persistent Be-XRBs. This system is the first evidence of a recent supernova in the low-density surroundings of NGC 602. We detect a shell nebula around 2dFS 3831 in H? and [O III] images and conclude that it is most likely a supernova remnant. If it is linked to the supernova explosion that created this new X-ray pulsar, its kinematic age of (2-4) × 104 yr provides a constraint on the age of the pulsar.

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

2012-02-01

30

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

31

Progenitors of Recombining Supernova Remnants  

NASA Astrophysics Data System (ADS)

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.

2012-05-01

32

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

33

X-Ray Imaging and Spectroscopy of the Supernova Remnant CTB 109 and Its Associated Pulsar 1E 2259+586  

NASA Astrophysics Data System (ADS)

We present the results of our analysis of the X-ray spectral structure of the evolved supernova remnant CTB 109 (G109.1-1.0), using data from the ROSAT Position Sensitive Proportional Counter (PSPC) and Broad Band X-Ray Telescope (BBXRT). The deep broadband PSPC image shows the same overall remnant morphology as previous X-ray images but reveals many new details. The remnant appears as a hemispherical shell centered on the X-ray-bright central pulsar 1E 2259+586. Despite the substantial improvement in sensitivity of the PSPC image over previous images, no X-ray emission is detected from the western half of the remnant, consistent with the interpretation that the western shock front has been significantly decelerated by a dense molecular cloud. Enhanced emission along the cloud remnant boundary supports this interpretation. Among important new small-scale structures revealed are clumpy substructure within the jetlike lobe running northeastward from the pulsar to the shell, and extended emission, with 2-3 arc minute radius, around 1E 2259+586. Spatially resolved spectroscopy using the PSPC reveals an overall column density variation across the remnant as well as intrinsic spectral variations. In particular, the spectrum over most of the shell is well fitted by a single-component thermal model, while for the lobe, the northern and southern shell, two thermal components are required, with one having parameter values similar to that found in those regions fitted by a single-component model. We conclude that either the thermal conditions vary within the remnant or there exists a second, distinct gas component in some parts of the remnant. A simultaneous fit to BBXRT and PSPC spectra for part of the interior and shell to the south of the pulsar shows that the plasma there is not in ionization equilibrium. The results of fitting these spectra using nonequilibrium ionization models are ambiguous, however: equally acceptable fits were obtained using models with and without electron-ion equipartition, but with very different parameter values. The best nonequipartition model yields shock temperature Ts = 2 × 107 K and ionization parameter n0t = 430 cm-3 yr, suggesting extreme departure from ionization equilibrium, while the best-fit equipartition model indicates conditions near ionization equilibrium, with Ts = 1.8 × 106 K and n0t = 17,000 cm-3 yr. The thermal nature of the emission from the lobe is counter to the prediction of the hypothesis that it arises from a precessing jet and contrasts with the nonthermal lobes in SS433/W50. Thus, the lobe in CTB 109 is probably not related to or powered by the central pulsar. The similarity of the lobe spectrum to those of the northern and southern shell segments suggests they are physically related. Together they form a plumelike structure whose morphology and location relative to the molecular cloud suggest that they represent gas from the remnant interior, swept up and reheated by a shock reflected off the molecular cloud, as reproduced in hydrodynamical simulations (see Tenorio-Tagle et al.). A timing analysis of the PSPC data for 1E 2259+586 yields a period of 6.978814 +/- 9.4 × 10-6 s, consistent with a constant ?. Simultaneous fitting of the pulsar spectra from the PSPC, BBXRT, and the ASCA are best modeled by a blackbody (kT = 0.43 keV). The extended emission around 1E 2259+586 has an extent of 2'-3' in both the PSPC and ROSAT HRI images. Its nonthermal spectrum suggests that it arises from a synchrotron nebula, although we cannot rule out the possibility of a dust-scattering halo.

Rho, Jeonghee; Petre, R.

1997-07-01

34

Pulsars, supernovae, and ultrahigh energy cosmic rays  

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 10^{19} eV as indicated by air shower studies reported by the Auger Observatory. 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 10^{16} and 10^{18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, differing considerably between the energy scale used by Auger and that used by the Telescope Array. Depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy, the contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum below the ankle. Fast spinning newborn pulsars that could produce UHECRs would be born in supernovae that could present interesting specific radiative features, due to the interaction of the pulsar wind with the surrounding ejecta. The resulting supernova lightcurves could present a high luminosity plateau over a few years, and a bright X-ray and gamma-ray peak around one or two years after the onset of the explosion. If such signatures were observed, they could have important implications both for UHECR astrophysics and for the understanding of core-collapse supernovae.

Kotera, K.; Fang, K.; Olinto, A. V.; Phinney, E. S.

2012-12-01

35

Supernova Remnant SNR 0509 lithograph  

NSDL National Science Digital Library

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

36

ASCA observations of supernova remnants  

NASA Technical Reports Server (NTRS)

The combined spectral and imaging capabilities of the Advanced Satellite for Cosmology and Astrophysics (ASCA) provides new possibilities for studying supernova remnants. The most powerful of these are spatially resolved, moderate resolution spectroscopy and narrowband spectral imaging. The use of these techniques yielded a number of results that challenge the currently held views on X-ray emission processes in supernova remnants. Evidence was found for the plasmas in which a different ionization timescale must be used to characterize each metal. Some recent findings from supernova remnant surveys conducted using ASCA are presented.

Petre, R.

1996-01-01

37

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

38

Magnetohydrodynamic turbulence in supernova remnants  

Microsoft Academic Search

We present estimates of the angular power spectra of the synchrotron radiation intensity fluctuations at 6 and 20 cm for the shell-type supernova remnant Cas A and the filled-centre Crab supernova remnant. We find that the intensity fluctuations of both the sources have a power-law power spectrum with index -3.24 +\\/- 0.03. This power-law power spectrum is consistent with the

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

2009-01-01

39

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

NASA Astrophysics Data System (ADS)

Context. The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs), which can be investigated in detail with radio, optical, and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. Aims: We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. Methods: We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical, and X-ray images and investigated the energy spectra in the different parts of the remnant. Results: Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index ?Core of -0.04 ± 0.04, while in the rest of the SNR shell the spectral slope is somewhat steeper with ?Shell = -0.43 ± 0.01. We detect regions with a mean polarisation of P ? (12 ± 4)% at 6 cm and (9 ± 2)% at 3 cm. The full remnant is of roughly circular shape with dimensions of (31 ± 1) pc × (29 ± 1) pc. The spectral analysis of the XMM-Newton EPIC and RGS spectra allowed us to derive physical parameters for the SNR. Somewhat depending on the spectral model, we obtain for the remnant a shock temperature of around 0.2 keV and estimate the dynamical age to 12 000-15 000 years. Using a Sedov model we further derive an electron density in the X-ray emitting material of 1.56 cm-3, typical for LMC remnants, a large swept-up mass of 830 M?, and an explosion energy of 7.6 × 1050 erg. These parameters indicate a well evolved SNR with an X-ray spectrum dominated by emission from the swept-up material.

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

2012-07-01

40

Neutron Stars in Supernova Remnants  

Microsoft Academic Search

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

Franco Pacini

1999-01-01

41

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

NASA Technical Reports Server (NTRS)

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

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

2005-01-01

42

Chandra Associates Pulsar and Historic Supernova  

NASA Astrophysics Data System (ADS)

SAN DIEGO -- Scientists using NASA’s 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 Japan’s 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 pulsar’s 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

43

Discovery of a Young, Energetic Pulsar Near the Supernova Remnant G290.1-0.8 and the Gamma-Ray Source 2EG J1103-6106  

NASA Technical Reports Server (NTRS)

We report on the discovery and follow-up timing observations of a 63-ms radio pulsar, PSR J1105-6107. We show that the pulsar is young, having a characteristic age of only 63kyr. We consider its possible association with the nearby remnant G290.1-0.8 (MSH 11-61A) but uncertainties in the distances and ages preclude a firm conclusion.

Kaspi, V. M.; Bailes, M.; Manchester, R. N.; Stappers, B. W.; Sandhu, J.; Navarro, J.; D'Amico, N.

1996-01-01

44

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

45

Identifying Elements in Supernova Remnants  

NSDL National Science Digital Library

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

2007-02-02

46

MHD interaction of pulsar wind nebulae with SNRs and with the ISM  

Microsoft Academic Search

In the late 1960s the discovery of the Crab pulsar in its associated supernova remnant, launched a new field in supernova remnant research: the study of pulsar-driven or plerionic supernova remnants. In these type of remnants, the relativistic wind emitted by the pulsar, blows a pulsar wind nebula into the interior of its supernova remnant. Now, more then forty years

E. van der Swaluw

2005-01-01

47

BBXRT observations of supernova remnants  

NASA Technical Reports Server (NTRS)

The Broad Band X-ray Telescope (BBXRT) was designed to perform sensitive, moderate resolution spectroscopy of cosmic X-ray sources in the 0.3-10 keV band from the Space Shuttle. During its nine-day flight in December, 1990, the BBXRT observed a variety of supernova remnants and related objects. We present results from some of these observations, emphasizing the ability of the BBXRT to perform spatially-resolved spectroscopy. The improved specral resolution and efficiency over previous instruments makes possible measurements of previously undetectable lines, and the broad bandpass allows simultaneous measurements of lines from oxygen through iron.

Petre, R.; Serlemitsos, P.; Marshall, F.; Jahoda, K.; Szymkowiak, A.; Smale, A.; Swank, J.; Corcoran, M.; Ptak, A.; Boldt, E.

1993-01-01

48

Generating Pulsar Spin in Supernovae  

NASA Astrophysics Data System (ADS)

Using three-dimensional hydrodynamics simulations, we have identified a robust instability of the stalled accretion shock in core-collapse supernovae that is able to generate a strong rotational flow in the vicinity of the accreting proto-neutron star (PNS). Sufficient angular momentum is deposited on the PNS to generate a final neutron star spin period consistent with observations of radio pulsars, even beginning with spherically symmetric, non-rotating initial conditions. This provides a new mechanism for the generation of neutron star spin and weakens, if not breaks, the assumed correlation between the rotational periods of supernova progenitor cores and pulsar spin. This research used resources of the National Center for Computational Sciences at Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.

Blondin, John M.; Mezzacappa, A.

2006-12-01

49

Modelling of the radio emission from the Vela supernova remnant  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) are widely considered to be sites of Galactic cosmic ray (CR) acceleration. Vela is one of the Galactic composite SNRs closest to Earth accompanied by the Vela pulsar and its pulsar wind nebula (PWN) Vela X. The Vela SNR is one of the most studied remnants and it benefits from precise estimates of various physical parameters such as distance and age. Therefore, it is a perfect object for a detailed study of physical processes in SNRs. The Vela SNR expands into the highly inhomogeneous cloudy interstellar medium (ISM) and its dynamics are determined by the heating and evaporation of ISM clouds. It features an asymmetrical X-ray morphology, which is explained by the expansion into two media with different densities. This could occur if the progenitor of the Vela SNR exploded close to the edge of the stellar wind bubble of the nearby Wolf-Rayet star ?2 Velorum causing one part of the remnant to expand into the bubble. The interaction of the ejecta and the main shock of the remnant with ISM clouds causes formation of secondary shocks at which additional particle acceleration takes place. This may lead to the almost uniform distribution of relativistic particles inside the remnant. We calculate the synchrotron radio emission within the framework of the new hydrodynamical model that assumes the supernova explosion at the edge of the stellar wind bubble. The simulated radio emission agrees well with both the total radio flux from the remnant and the complicated radio morphology of the source.

Sushch, I.; Hnatyk, B.

2014-01-01

50

A revised Galactic supernova remnant catalogue  

Microsoft Academic Search

A revised catalogue of 274 Galactic supernova remnants (SNRs) is presented, along with some simple statistics of their parameters. It is shown that the remnants that have recently been identified are generally faint, as is expected from the selection effects that apply to the identification of remnants.

D. A. Green

2009-01-01

51

Remnant Stars in Supernova Remnants-Aug - CYC3HIGH  

NASA Astrophysics Data System (ADS)

The low frequency of occurrence of identified neutron stars located in supernova remnants (SNR's) is an unexplained embarassment to our generally accepted theories of stellar evolution and neutron star formation. We propose to search recent SNR's for any remnant star associated with them, and to study the photometric variability of known examples of neutron stars which are remnants of supernovae. The results will place important constraints on the mechanisms by which neutron stars originate. Revision History: Prepared for augmentation submission--Dolan 5/8/92;

Bless, Robert

1993-07-01

52

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

53

THE VLT-FLAMES TARANTULA SURVEY: THE FASTEST ROTATING O-TYPE STAR AND SHORTEST PERIOD LMC PULSAR-REMNANTS OF A SUPERNOVA DISRUPTED BINARY?  

SciTech Connect

We present a spectroscopic analysis of an extremely rapidly rotating late O-type star, VFTS102, observed during a spectroscopic survey of 30 Doradus. VFTS102 has a projected rotational velocity larger than 500 km s{sup -1} and probably as large as 600 km s{sup -1}; as such it would appear to be the most rapidly rotating massive star currently identified. Its radial velocity differs by 40 km s{sup -1} from the mean for 30 Doradus, suggesting that it is a runaway. VFTS102 lies 12 pc from the X-ray pulsar PSR J0537-6910 in the tail of its X-ray diffuse emission. We suggest that these objects originated from a binary system with the rotational and radial velocities of VFTS102 resulting from mass transfer from the progenitor of PSR J0537-691 and the supernova explosion, respectively.

Dufton, P. L.; Dunstall, P. R.; Fraser, M. [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Evans, C. J. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Brott, I. [University of Vienna, Department of Astronomy, Tuerkenschanzstr. 17, A-1180 Vienna (Austria); Cantiello, M.; Langer, N. [Argelander Institut fuer Astronomie der Universitaet Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); De Koter, A.; Sana, H. [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands); De Mink, S. E. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Henault-Brunet, V.; Taylor, W. D. [Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Howarth, I. D. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lennon, D. J. [ESA, Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Markova, N., E-mail: p.dufton@qub.ac.uk [Institute of Astronomy with NAO, Bulgarian Academy of Sciences, P.O. Box 136, 4700 Smoljan (Bulgaria)

2011-12-10

54

Supernova SN 1987A - Rotation rate of the central pulsar  

Microsoft Academic Search

Using available observational data on supernova SN 1987A, firm quantitative lower limits on the rotation period of the central pulsar (assuming the pulsar luminosity to power the supernova light curve) are derived. It is also demonstrated that pulsars born in type II supernovae are, in general, unlikely to be fast pulsars.

Harish C. Bhatt; Bhaskar Datta

1989-01-01

55

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.; Neuhäuser, R.; Hohle, M. M.

2013-10-01

56

Supernova Remnant in 3-D  

NASA Technical Reports Server (NTRS)

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

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

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

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

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

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

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

2009-01-01

57

Probing interstellar magnetic fields with Supernova remnants  

NASA Astrophysics Data System (ADS)

As Supernova remnants expand, their shock waves are freezing in and compressing the magnetic field lines they encounter; consequently we can use Supernova remnants as magnifying glasses for their ambient magnetic fields. We will describe a simple model to determine emission, polarization, and rotation measure characteristics of adiabatically expanding Supernova remnants and how we can exploit this model to gain information about the large scale magnetic field in our Galaxy. We will give two examples: The SNR DA530, which is located high above the Galactic plane, reveals information about the magnetic field in the halo of our Galaxy. The SNR G182.4+4.3 is located close to the anti-centre of our Galaxy and reveals the most probable direction where the large-scale magnetic field is perpendicular to the line of sight. This may help to decide on the large-scale magnetic field configuration of our Galaxy. But more observations of SNRs are needed.

Kothes, Roland; Brown, Jo-Anne

2009-04-01

58

X-ray halos around supernova remnants  

NASA Technical Reports Server (NTRS)

The results are reported of an Einstein Observatory imaging proportional counter investigation of the X-ray halos of the four brightest young Galactic supernova remnants: the Crab Nebula, Cas A, Tycho's, and Kepler's supernova remnant. It is found that the size, shape, and rough intensity of each of these sources are consistent with the measured properties of the X-ray halos of compact Galactic X-ray sources, and as such are consistent with an origin due solely to the scattering of X-rays by interstellar grains.

Mauche, Christopher W.; Gorenstein, Paul

1989-01-01

59

Nonthermal X-rays from supernova remnants  

NASA Astrophysics Data System (ADS)

Since the discovery of nonthermal X-rays in the shell-type supernova remnant SN1006 almost 20 years ago, the field has developed considerably, owing significant progress to our understanding of particle acceleration. Key to the characterization of the nonthermal emission is the ability of current satellites, XMM-Newton and Chandra, to perform spatially resolved spectroscopy at a relatively small spatial scale. In this review, I intend to present the main contributions of the study of nonthermal X-rays from supernova remnants to the understanding of particle acceleration.

Decourchelle, Anne

2014-01-01

60

X-ray spectra of supernova remnants  

NASA Technical Reports Server (NTRS)

X-ray spectra were obtained from fields in three supernova remnants with the solid state spectrometer of the HEAO 2 satellite. These spectra, which contain lines from K-shell transitions of several abundant elements with atomic numbers between 10 and 22, were compared with various models, including some of spectra that would be produced by adiabatic phase remnants when the time-dependence of the ionization is considered.

Szymkowiak, A. E.

1985-01-01

61

Imagery and spectroscopy of supernova remnants and H-2 regions  

NASA Technical Reports Server (NTRS)

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

Dufour, R. J.

1984-01-01

62

The Chandra Supernova Remnant Catalog  

NASA Astrophysics Data System (ADS)

We show some examples from a WWW-based catalog, containing Chandra archive data, that is now under construction. Many remnants show manifestations of internal neutron stars, which are of particular interest to this conference.

Seward, F.; Smith, R.; Hagler, J.; Portolese, L.; Gaetz, T.; Slane, P.; Koo, B.-C.; Lee, J.-J.

63

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

64

Autopsy of the Supernova Remnant Cassiopeia A  

NASA Astrophysics Data System (ADS)

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

Milisavljevic, Dan; Fesen, Robert A.

2014-01-01

65

"Suzaku Highlight Results on Supernova Remnants"  

NASA Technical Reports Server (NTRS)

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

Petre, Robert

2006-01-01

66

Grain Destruction in Evolving Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernova remnant (SNR) shocks are believed to be the primary regions of destruction for interstellar dust grains. This destruction occurs primarily because of the grain acceleration that occurs when the shock causes the gas and magnetic field to be compressed. Most calculations of grain destruction in shocks have used steady, plane parallel shocks, but in the interstellar medium most shocks result from SNRs and have significant time dependent and non-planar effects. We present new results for grain destruction that use numerical hydrodynamical calculations of supernova remnant evolution and include all important grain processes. We show that the lower density behind SNR shocks leads to substantially less grain destruction, alleviating the discrepancy between the grain destruction and creation timescales for silicate grains.

Slavin, Jonathan David

2014-06-01

67

Supernova remnants in the Large Magellanic Cloud.  

NASA Astrophysics Data System (ADS)

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

Dickel, J. R.

1994-06-01

68

Shocked Clouds in the Vela Supernova Remnant  

NASA Technical Reports Server (NTRS)

Unusually strong high-excitation C I has been detected in eleven lines of sight through the Vela supernova remnant by means of UV absorption-line studies of IUE data. Most of these lines of sight lie near the western edge of the X-ray bright region of the supernova remnant in a spatially distinct band approximately 1deg by 4deg oriented approximately north/south. The high-excitation C I (denoted C I*) is interpreted as evidence of a complex of shocked dense clouds inside the supernova remnant, due to the high pressures indicated in this region. To further analyze the properties of this region of C I*, we present new HIRES-processed IRAS data of the entire Vela SNR. A temperature map calculated from the HIRES IRAS data, based on a two-component dust model, reveals the signature of hot dust at several locations in the SNR. The hot dust is anti-correlated spatially with X-ray emission as revealed by ROSAT, as would be expected for a dusty medium interacting with a shock wave. The regions of hot dust are strongly correlated with optical filaments, supporting a scenario of dense clouds interior to the SNR that have been shocked and are now cooling behind the supernova blast wave. With few exceptions, the lines of sight to the strong C I* pass through regions of hot dust and optical filaments. Possible mechanisms for the production of the anomalously large columns of C I and C I* are discussed. Dense clouds on the back western hemisphere of the remnant may explain the relatively low X-ray emission in the western portion of the Vela supernova remnant due to the slower forward shock velocity in regions where the shock has encountered the dense clouds. An alternate explanation for the presence of neutral, excited state, and ionized species along the same line of sight may be a magnetic precusor that heats and compresses the gas ahead of the shock.

Nichols, Joy S.; Slavin, Jonathan D.

2004-01-01

69

EGRET Observations of Radio-bright Supernova Remnants  

Microsoft Academic Search

The gamma-ray emission associated with radio-bright supernova remnants has been studied using data from the EGRET instrument aboard the Compton Gamma Ray Observatory. Five sources from The Second EGRET Catalog of High-Energy Gamma-Ray Sources are shown to be coincident with supernova remnants. The two strongest pointlike gamma-ray excesses which are coincident with supernova remnants are 2EG J2020+4026 with y Cyg

Joseph A. Esposito; Stanley D. Hunter; Gottfried Kanbach; P. Sreekumar

1996-01-01

70

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

NSDL National Science Digital Library

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

2011-01-01

71

Galactic supernova remnants: an updated catalogue and some statistics  

Microsoft Academic Search

A catalogue of 231 Galactic supernova remnants (SNRs) is presented, and the selection effects applicable to the identification of remnants at radio wavelengths are discussed. In addition to missing low surface brightness remnants, small angular size i.e. young but distant remnants are also missing from the current catalogue of Galactic SNRs. Several statistical properties of Galactic SNRs are discussed, including

D. A. Green

2004-01-01

72

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

73

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

74

The molecular emission from old supernova remnants  

NASA Astrophysics Data System (ADS)

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

Gusdorf, A.; Güsten, R.; Anderl, S.; Hezareh, T.; Wiesemeyer, H.

2014-01-01

75

Vivid View of Tycho's Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

76

Multi-Wavelength Observations of Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Williams, B.

2012-01-01

77

Submillisecond optical pulsar in supernova 1987A  

NASA Technical Reports Server (NTRS)

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 an amplitude of 1.5 x 10 to the -3rd Hz and a period of 8 hr. If this is interpreted as the result of a binary orbit, it suggests that there may be a Jupiter-size object orbiting the pulsar at a distance of 10 to the 6th km.

Kristian, J.; Pennypacker, C. R.; Morris, D. E.; Muller, R. A.; Middleditch, J.; Hamuy, M. A.; Kunkel, W. E.; Imamura, J. N.; Lucinio, R.; Steiman-Cameron, T. Y.

1989-01-01

78

VHE Gamma-ray Supernova Remnants  

SciTech Connect

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

Funk, Stefan; /KIPAC, Menlo Park

2007-01-22

79

The Origin of Kepler's Supernova Remnant  

NASA Astrophysics Data System (ADS)

It is now well established that Kepler's supernova remnant (SNR) is the result of a Type Ia explosion. With an age of 407 yr and an angular diameter of ~4', Kepler is estimated to be between 3.0 and 7.0 kpc distant. Unlike other Galactic Type Ia SNRs such as Tycho and SN 1006, and SNR 0509-67.5 in the Large Magellanic Cloud, Kepler shows evidence for a strong circumstellar interaction. A bowshock structure in the north is thought to originate from the motion of a mass-losing system through the interstellar medium prior to the supernova. We present results of hydrodynamical and spectral modeling aimed at constraining the circumstellar environment of the system and the amount of 56Ni produced in the explosion. Using models that contain either 0.3 M ? (subenergetic) or 1.0 M ? (energetic) of 56Ni, we simulate the interaction between supernova Ia ejecta and various circumstellar density models. Based on dynamical considerations alone, we find that the subenergetic models favor a distance to the SNR of <6.4 kpc, while the model that produces 1 M ? of 56Ni requires a distance to the SNR of >7 kpc. The X-ray spectrum is consistent with an explosion that produced ~1 M ? of 56Ni, ruling out the subenergetic models, and suggesting that Kepler's SNR was an SN 1991T-like event. Additionally, the X-ray spectrum rules out a pure r -2 wind profile expected from isotropic mass loss up to the time of the supernova. Introducing a small cavity around the progenitor system results in modeled X-ray spectra that are consistent with the observed spectrum. If a wind-shaped circumstellar environment is necessary to explain the dynamics and X-ray emission from the shocked ejecta in Kepler's SNR, then we require that the distance to the remnant be greater than 7 kpc.

Patnaude, Daniel J.; Badenes, Carles; Park, Sangwook; Laming, J. Martin

2012-09-01

80

Chandra Observations of Supernova Remnants and Neutron Stars: An Overview  

NASA Technical Reports Server (NTRS)

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

Weisskopf, Martin C.

2002-01-01

81

Is PSR 1509-58 the remnant of supernova AD 185?  

NASA Technical Reports Server (NTRS)

Thorsett has recently advanced the proposal that the counterpart of the supernova recorded by Chinese astronomers in AD 185 is the pulsar PSR 1509-58 in the supernova remnant MSH 15-52. This proposal is attractive since it was claimed to better fit the visibility contraints that plagued earlier identifications and since the spin-down age of the pulsar is 1690 years. I have examined in detail the question of the visibility of a supernova at the proposed position and find that the reported dates of visibility can be matched only if the supernova appeared substantially brighter than Venus at its peak. For the distance and extinction to the pulsar, this implies M(sub V) (max) was brighter than -21.4 mag, whereas the brightest known absolute magnitude of a Type II supernova is -19.65 (H(sub 0) = 75 km/s/Mpc). Thus, the high required luminosity can be used as good evidence against the identification of SN 185 with PSR 1509-58. However, if the identification is retained, then Hubble's Constant would have to have a small value and/or the supernova had to have been a type IIP event with exceptional brilliance. The earlier identification of SN 185 with MSH 14-63 by Clark and Stephenson can also be reconciled with the visibility data.

Schaefer, Bradley E.

1993-01-01

82

Three Great Eyes on Kepler's Supernova Remnant  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Composite

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

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

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

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

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

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

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

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

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

2004-01-01

83

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

84

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

NASA Technical Reports Server (NTRS)

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

Slane, Patrick O.

1997-01-01

85

A Newly Discovered Supernova Remnant and MSH 11-62 and 3C58  

NASA Technical Reports Server (NTRS)

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

Slane, Patrick O.

2000-01-01

86

Exploration of Galactic ?-ray supernova remnants  

NASA Astrophysics Data System (ADS)

New generational very-high-energy telescope arrays have been detecting more than 120 TeV ?-ray sources. Multi-wavelength observations on these ?-ray sources have proven to be robust in shedding light on their nature. The coming radio telescope arrays like ASKAP and FAST may find more faint (extended) radio sources due to their better sensitivities and resolutions, might identify more previously un-identified ?-ray sources and set many new targets for future deep surveys by very-high-energy ground-based telescopes like LHAASO. We in the paper summarize a list of known Galactic ?-ray Supernova Remnants (SNRs) with or without radio emissions so far, which includes some SNRs deserving top priority for future multi-wave-length observations.

Tian, WenWu; Zhang, JianLi

2013-08-01

87

Exosat observations of the Kepler supernova remnant  

SciTech Connect

The medium-energy experiment on board Exosat was used to measure the X-ray spectrum of the Kepler supernova remnant over the range 1.5-10 keV. An Fe emission line was clearly resolved with an energy of about 6.5 keV and equivalent width of about 1.8 keV. This was superposed on a continuum with a temperature of 5.0(+3.8, -1.9) keV. The medium-energy spectrum is shown to be consistent with a model in which the Kepler SNR is presently in a Sedov phase of evolution, the 5 keV continuum arises from the shocked interstellar/circumstellar medium, and thermal (but not ionization) equilibrium exists between electrons and ions behind the primary shock front. However, in this case, an overabundance of iron by more than 6 times cosmic is required. 28 refs.

Smith, A.; Peacock, A.; Arnaud, M.; Ballet, J.; Rothenflug, R. (ESA, Space Science Dept., Noordwijk (Netherlands) CEA, Centre d'Etudes Nucleaires de Saclay, Gif-sur-Yvette (France))

1989-12-01

88

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

89

Supernova remnants and the physics of strong shock waves  

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

90

Stellar spectroscopy methods for study of supernova remnants  

NASA Astrophysics Data System (ADS)

We present the method for study of the characteristics of the supernova remnants using their absorption properties. The background radiation sources are several stars with wide range of distances. Main task is accurate extraction of stellar spectra from observations. For Vela Jr. supernova remnant we found the absence of typical broad absorption in the spectral lines of Ca II doublet. Using modeles of supernovae remnants and data on radiation in ^{44}Ti ?-ray line we estimated the age and the distance to Vela Jr. We showed that a hypernova may be a probable candidate for Vela Jr. protogenitor.

Pakhomov, Yu. V.; Chugai, N. N.; Iyudin, A. F.

2011-01-01

91

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

92

Supernova Remnants with NuSTAR: Highlights and new discoveries  

NASA Astrophysics Data System (ADS)

Young supernova remnants represent a unique laboratory for the study of supernova explosion dynamics and particle acceleration in the local universe. In the hard X-ray band probed by NuSTAR (3-79 keV), the continuum emission is thought to be dominated by synchrotron radiation from ~TeV electrons, while line emission at 68 and 78 keV is produced by the decay of radioactive 44Ti synthesized in the supernova explosion. Here we present highlights of the supernova remnant science from the first two years of the NuSTAR mission.

Grefenstette, Brian

2014-08-01

93

Supernova remnants and the origin of cosmic rays  

NASA Astrophysics Data System (ADS)

Supernova remnants have long been considered to be the dominant sources of Galactic cosmic rays. For a long time the prime evidence consisted of radio synchrotron radiation from supernova remnants, indicating the presence of electrons with energies of several GeV. However, in order to explain the cosmic ray energy density and spectrum in the Galaxy supernova remnant should use 10% of the explosion energy to accelerate particles, and about 99% of the accelerated particles should be protons and other atomic nuclei. Over the last decade a lot of progress has been made in providing evidence that supernova remnant can accelerate protons to very high energies. The evidence consists of, among others, X-ray synchrotron radiation from narrow regions close to supernova remnant shock fronts, indicating the presence of 10-100 TeV electrons, and providing evidence for amplified magnetic fields, gamma-ray emission from both young and mature supernova remnants. The high magnetic fields indicate that the condition for accelerating protons to >1015 eV are there, whereas the gamma-ray emission from some mature remnants indicate that protons have been accelerated.

Vink, Jacco

2014-01-01

94

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

NASA Technical Reports Server (NTRS)

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

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

2000-01-01

95

Discovery of a galactic supernova remnant with ROSAT  

NASA Astrophysics Data System (ADS)

A previously unknown supernova remnant has been discovered during the Rosat X-ray all-sky survey. The remnant, which is of almost perfect spherical shape with a diameter of 108 arcmin shows an X-ray flux of 1.9 x 10 to the -10th erg/sq cm/s between 0.1 and 2.4 keV, ranking it among the 10 brightest galactic supernova remnants. Based on the Sedov analysis the progenitor star went off 25,000 yrs ago expanding into a very low density medium of 0.01 atoms/cu cm. Both the low interstellar matter density and the intervening photoelectric absorption result in a distance estimate of about 3 kpc, which would place the remnant in the interarm region between the local Orion arm and Perseus arm suggesting a type-I event for the supernova. The classification as a galactic supernova remnant has been confirmed by follow-up radio observations, which revealed a radio surface brightness about a factor of 4 lower than that of any remnant known so far. If low radio brightness is common to old remnants radio surveys may have missed a substantial number, impacting on previous estimates about the galactic supernova rate and the energy input to the interstellar medium.

Pfeffermann, E.; Aschenbach, B.; Predehl, P.

1991-06-01

96

Shock Destruction of Dust in Supernova Remnants  

NASA Astrophysics Data System (ADS)

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

Shull, J.

2008-07-01

97

Nonspherical supernova remnants. IV - Sequential explosions in OB associations  

NASA Technical Reports Server (NTRS)

Multisupernova remnants, driven by sequential supernova explosions in OB associations, are modelled by means of two-dimensional hydrodynamical calculations. It is shown that due to the Rayleigh-Taylor instability the remnants quickly evolve into highly irregular structures. A critical evaluation of the multisupernova model as an explanation for supershells is given.

Tenorio-Tagle, G.; Bodenheimer, P.; Rozyczka, M.

1987-01-01

98

XMM-Newton Observations of Two Candidate Supernova Remnants  

NASA Astrophysics Data System (ADS)

Candidate supernova remnants (SNRs) G23.5+0.1 and G25.5+0.0 were observed by XMM-Newton in the course of a snapshot survey of plerionic and composite SNRs in the Galactic plane. In the field of G23.5+0.1, we detected an extended source, ~3' in diameter, which we tentatively interpret as a pulsar wind nebula (PWN) of the middle-aged radio pulsar B1830-08 (J1833-0827; P = 85.3 ms, ? = 147 kyr, \\dot{E} = 5.8 × 1035 erg s-1, d = 5.7 kpc), with the PWN luminosity L 0.2-10 keV ? 5 × 1033 erg s-1 ? 8 × 10-3 \\dot{E}. The pulsar is not resolved in the EPIC images. Our analysis suggests an association between PSR B1830-08 and the surrounding diffuse radio emission. If the radio emission is due to the SNR, then the pulsar must be significantly younger than its characteristic age. Alternatively, the radio emission may come from a relic PWN. The field also contains SGR 1833-0832 and another middle-aged pulsar B1829-08 (J1832-0827; P = 647 ms, ? = 161 kyr, \\dot{E} = 9.3 × 1033 erg s-1, d = 4.7 kpc), none of which are detected in our observation. In the field of G25.5+0.0, which contains the extended TeV source HESS J1837-069, we detected the recently discovered young high-energy pulsar J1838-0655 (P = 70.5 ms, ? = 23 kyr, \\dot{E}= 5.5 × 1036 erg s-1) embedded in a PWN with extent of 1farcm3. The unabsorbed pulsar + PWN luminosity is L 2-11 keV ? 2 × 1034 erg s-1 ? 4 × 10-3 \\dot{E} at an assumed distance of 7 kpc. We also detected another PWN candidate (AX J1837.3-0652) with an extent of 2' and unabsorbed luminosity L 2-10 keV ? 4 × 1033 erg s-1 at d = 7 kpc. The third X-ray source, located within the extent of the HESS J1837-069, has a peculiar extended radio counterpart, possibly a radio galaxy with a double nucleus or a microquasar. We did not find any evidence of the SNR emission in the G25.5+0.0 field. We provide detailed multiwavelength analysis and identifications of other field sources and discuss robustness of the G25.5+0.0 and G23.5+0.1 classifications as SNRs. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA.

Kargaltsev, O.; Schmitt, B. M.; Pavlov, G. G.; Misanovic, Z.

2012-01-01

99

Supernova remnants across the Hubble sequence  

NASA Astrophysics Data System (ADS)

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

Chomiuk, Laura Beth

100

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

101

MODIFIED EQUIPARTITION CALCULATION FOR SUPERNOVA REMNANTS  

SciTech Connect

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

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

2012-02-10

102

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

103

High-Energy Emission From the Composite Supernova Remnant MSH 15-56  

NASA Astrophysics Data System (ADS)

Composite supernova remnants (SNRs) are those consisting of a central pulsar that produces a wind of synchrotron-emitting relativistic particles, and a supernova (SN) blast wave that expands into the surrounding interstellar medium (ISM). At the late stages of a composite SNR's evolution, the SN reverse shock crushes the pulsar wind nebula (PWN), resulting in complex filamentary structures and mixing of the PWN material with ejecta gas. This interaction is even more complex in cases where the PWN is displaced from the SNR center, either due to the pulsar's motion or an asymmetric reverse shock resulting from a density gradient in the ambient ISM. The composite nature of the SNR MSH 15-56 is clearly seen in the radio observations that show an SNR shell with a displaced PWN. We present an updated analysis of the XMM-Newton and Chandra X-ray observations of this remnant that reveals complex structures indicative of a disrupted PWN and provides evidence for mixing of the SN ejecta with PWN material following a reverse shock interaction. The increase in the magnetic field due to such an interaction produces an excess of low energy particles and may give rise to gamma-ray emission through inverse Compton scattering. Indeed, a gamma-ray source recently detected by Fermi appears to spatially coincide with the SNR, and may originate from the PWN. We discuss the SNR parameters derived from the X-ray observations and the possible origin of the high-energy gamma-ray emission.

Temim, Tea; Slane, P.; Plucinsky, P.; Gelfand, J.; Castro, D.

2012-05-01

104

The prevalence of supernova remnants among unidentified Galactic radio sources  

NASA Technical Reports Server (NTRS)

Nine Galactic radio sources were mapped to identify new Crab-like and composite supernova remnants. The sources were selected on the basis of existing stringent upper limits on their hydrogen recombination line fluxes. One new Cracb-like remnant, one new composite remnant, at least one, and probably two, new shell-like remnants, and a compact H II region were found, along with the expected collection of extragalactic objects. The results suggest that there are several hundred SNRs in the Galaxy which are detectable with current instruments, but which have yet to be identified.

Helfand, David J.; Velusamy, T.; Becker, R. H.; Lockman, Felix J.

1989-01-01

105

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.

106

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

107

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

NASA Astrophysics Data System (ADS)

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

Slane, Patrick O.; Hughes, J. P.; Temim, T.; Rousseau, R.; Castro, D.; Foight, D.; Gaensler, B. M.; Funk, S.; Lemoine-Goumard, M.; Gelfand, J. D.; Moffett, D. A.; Dodson, R. G.; Bernstein, J. P.

2012-05-01

108

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

109

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

SciTech Connect

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

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

2012-04-20

110

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

111

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

112

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.; Olguín, L.; Frew, D. J.; Stupar, M.; Vázquez, R.; Wright, N. J.; Corradi, R. L. M.; Morris, R. A. H.

2013-05-01

113

Dust Destruction in the Cygnus Loop Supernova Remnant  

NASA Astrophysics Data System (ADS)

The Cygnus Loop supernova remnant serves as an excellent laboratory for the study of radiative and non-radiative shocks with speeds in the 150-450 km s-1 range. We present results on shock-excited emission and dust destruction based on Spitzer Space Telescope observations of two well-studied regions in the remnant, (i) a non-radiative shock filament along the NE limb, and (ii) the XA region, characterized by emission from bright radiative shocks.

Sankrit, Ravi; Blair, William P.; Raymond, John C.; Williams, Brian J.

2014-01-01

114

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

115

Supernova remnants associated with an H I 'supershell' in the Perseus spiral arm  

Microsoft Academic Search

A large (280 pc diameter) H I shell has been found in the Perseus spiral arm of our Galaxy. Three old supernova remnants are associated with the shell. These are the first supernova remnants directly linked to large H I shells. All three of these supernova remnants are located within the H I shell, at least two of them are

M. Fich

1986-01-01

116

Remnant Stars in Supernova Remnants-Cont of 1098  

NASA Astrophysics Data System (ADS)

In this proposal we will search for a remnant star associated with SN1987A. Once detected, we will study the photometric variability in an attempt to place important constraints on the mechanisms by which neutron stars originate. REVISION HISTORY: Created 11/18/91;

Bless, Robert

1992-07-01

117

The Crab Nebula and related supernova remnants; Proceedings of the Workshop, George Mason University, Fairfax, VA, October 11, 12, 1984  

NASA Technical Reports Server (NTRS)

Papers are presented on the Crab Nebula's composition, helium distribution, outer structure and jet, and evolution. Attention is given to line emission from supernova remnants and charge transfer reactions, a magnetohydrodynamic model of the Crab Nebula and its radiation, inferences made using data on the pulsed flux from the crab pulsar, a new interpretation of the crab pulsar X-ray interpulse radiation, and evolutionary models of the Crab Nebula's progenitor. Other topics include the evolution of the centimeter flux of 3C58 and the Crab Nebula, a search for a shock wave around the Crab Nebula, high resolution radio studies of the Crab Nebula, supernova shell structure, and the nature of the remnant 0540-693 and its implications for the study of crablike remnants. Papers are also presented on X-ray observations of: Crab-like remnants, the Crab Nebula, the Vela X region, W28, and 3C400.2. Other papers include the 50 millisecond pulsar in the Large Magellanic Cloud and the X-ray pulse emission mechanism, optical emission from the plerionic core of CTB 80, and one-arcminute resolution observations of W50.

Kafatos, M. C. (editor); Henry, R. B. C. (editor)

1985-01-01

118

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

Microsoft Academic Search

Examination of the interaction between supernova (SN) ejecta and the various environments in which the explosive event might occur shows that only a small fraction of the many SNs produce observable supernova remnants (SNRs). This fraction, which is found to depend weakly upon the lower mass limit of the SN progenitors, and more strongly on the specfic characteristics of the

M. Kafatos; S. Sofia; F. Bruhweiler

1980-01-01

119

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

120

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

121

The MIPSGAL View of Supernova Remnants in the Galactic Plane  

Microsoft Academic Search

We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 mum), in the coordinate ranges 10° < l < 65° and 285° < l < 350°, |b| < 1°, 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

D. Pinheiro Gonçalves; A. Noriega-Crespo; R. Paladini; P. G. Martin; S. J. Carey

2011-01-01

122

Hot interstellar tunnels. 1: Simulation of interacting supernova remnants  

NASA Technical Reports Server (NTRS)

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

Smith, B. W.

1976-01-01

123

The evolution of supernova remnants as radio sources  

Microsoft Academic Search

The acceleration of relativistic electrons by hydromagnetic turbulence in shell-type supernova remnants (SNRs) is examined in relation to their structural development through interaction with the interstellar medium. The transport equation governing the energy spectrum of the electrons is analytically solved, enabling study of the evolution of their synchrotron radio emission. The sudden emergence of SNRs as long-lived radio sources, several

R. Cowsik; S. Sarkar

1984-01-01

124

Postshock turbulence and diffusive shock acceleration in young supernova remnants  

Microsoft Academic Search

Context. Thin X-ray filaments are observed in the vicinity of young supernova remnants (SNR) blast waves. Identifying the process that creates these filaments would provide direct insight into the particle acceleration occurring within SNR and in particular the cosmic ray yield. Aims: We investigate magnetic amplification in the upstream medium of a SNR blast wave through both resonant and non-resonant

A. Marcowith; F. Casse

2010-01-01

125

Magnetic Field Structure and Collective Effects in Supernova Remnants  

Microsoft Academic Search

New observations of the northeast rim of the intermediate age supernova remnant IC 443 obtained at 20.9 cm with the VLA have resolved the bright filamentary clouds. The cloud width is consistent with the recombination\\/cooling length of optical filaments, but inconsistent with the evaporation time predicted for isolated, cold filamentary clouds in a hot interstellar medium. By considering collective evaporative

Craig A. Wood

1993-01-01

126

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

PubMed

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

Badenes, Carles

2010-04-20

127

Hydrodynamic instabilities in supernova remnants - Self-similar driven waves  

NASA Astrophysics Data System (ADS)

An initial study aimed at elucidating the multidimensional aspects of the hydrodynamic instabilities in supernova remnants is presented. Self-similar solutions are found to exist for the interaction of a steep power-law density profile expanding into a relatively flat stationary power-law density profile. Consideration of the pressure and entropy profiles in the shocked 1D flows shows that the flows are subject to convective instability, by a local criterion. The growth rate for the instability becomes very large near the contact discontinuity between the two shocked regions. A linear analysis of the complete self-similar solutions shows that the solutions are unstable above a critical wavenumber and that the growth rate is greatest at the position of the contact discontinuity. The X-ray image of the remnant of SN 1572 (Tycho) shows emission from clumps of supernova ejecta, which is good evidence for instabilities in this remnant.

Chevalier, Roger A.; Blondin, John M.; Emmering, Robert T.

1992-06-01

128

Optical emission-line properties of evolved galactic supernova remnants  

NASA Technical Reports Server (NTRS)

New optical spectrophotometric data are presented for the supernova remnants CTB 1, OA 184, VRO 42.05.01, S147, the Monoceros Loop, G206.9 + 2.3, and G65.3 + 5.7. These data are combined with published spectral data to study some of the general properties of evolved galactic supernova remnants. It is found that (1) O I and O II forbidden line strengths, when used in conjunction with the usual H-alpha S II forbidden line ratio test, provide an excellent additional diagnostic for discriminating remnants from H II regions; (2) the line ratios H-alpha forbidden line N II, H-alpha forbidden line S II, and forbidden line S II 6717/6731 A generally do not vary substantially among the filaments of an individual remnant; and (3) the observed correlation of forbidden line N II/H-alpha with S II forbidden line 6717/6731 A in remnants is the result of observational selection rather than of evolutionary effects. A galactic nitrogen abundance gradient of d log (N/H)/dR = -0.088 dex/kpc, which is in agreement with that derived from H II regions. However, no abundance gradients for oxygen or sulfur are indicated from the remnant data.

Fesen, R. A.; Blair, W. P.; Kirshner, R. P.

1985-01-01

129

Complex structure of the supernova remnant HB 3  

NASA Technical Reports Server (NTRS)

HB 3 is an old, large (84 pc diameter) supernova remnant associated with the W3 H II region/molecular cloud complex. Observations of the imaging proportional counter (IPC) onboard the Einstein X-ray astronomy satellite have been reprocessed to yield a contour map of X-ray brightness and spectra of various regions of this remnant. The measured IPC flux is 2.4 x 10 to the -11th ergs per sq cm per s, giving a 0.2-4 keV luminosity of 1.6 x 10 to the 35th ergs/s for a column densityof 6 x 10 to the 21st per sq cm. The measured X-ray temperatures reveal a decrease from center to limb of the remnant of 1-0.3 keV. HB 3 is in the late adiabatic blast-wave phase of evolution, 30,000 to 50,000 yr old and with an initial blast energy of 3 x 10 to the 50th ergs. The X-ray map is compared with available radio and optical images. In X-rays, HB 3 has two components - a diffuse emission inside the 84 pc radio remnant and a ring of emission at the center of 30 pc in diameter. The diffuse emission is similar to that from other supernova remnants which are moderately obscured (column density, nH approximately 10 to the 22nd per sq cm). Three possibilities for the origin of the ring are explored: (1) a second supernova remnant, (2) a shocked shell in the interstellar medium surrounding HB 3, and (3) reverse-shock heated ejecta. There is no hot neutron star within the remnant.

Leahy, D. A.; Venkatesan, D.; Long, K. S.; Naranan, S.

1985-01-01

130

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

NSDL National Science Digital Library

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

131

Modelling Hard Gamma-Ray Emission from Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Baring, Matthew G.

1999-01-01

132

Modelling Hard Gamma-Ray Emission from Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Baring, Matthew

2000-01-01

133

A 3D numerical model for Kepler's supernova remnant  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

134

Infrared echoes near the supernova remnant Cassiopeia A.  

PubMed

Two images of Cassiopeia A obtained at 24 micrometers with the Spitzer Space Telescope over a 1-year time interval show moving structures outside the shell of the supernova remnant to a distance of more than 20 arc minutes. Individual features exhibit apparent motions of 10 to 20 arc seconds per year, independently confirmed by near-infrared observations. The observed tangential velocities are at roughly the speed of light. It is likely that the moving structures are infrared echoes, in which interstellar dust is heated by the explosion and by flares from the compact object near the center of the remnant. PMID:15947181

Krause, Oliver; Rieke, George H; Birkmann, Stephan M; Le Floc'h, Emeric; Gordon, Karl D; Egami, Eiichi; Bieging, John; Hughes, John P; Young, Erick T; Hinz, Joannah L; Quanz, Sascha P; Hines, Dean C

2005-06-10

135

Limits on an optical pulsar in supernova 1987A  

NASA Technical Reports Server (NTRS)

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.

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.

1989-01-01

136

Supernova remnant rich fields in the Carina spiral arm  

NASA Technical Reports Server (NTRS)

The analysis of the ROSAT PSPC data on five fields containing supernova remnants several months ago was completed. Dr. Una Hwang, prepared a paper describing our results which was published last August ('An X-ray Study of Five Supernova Remnants in the Carina Spiral Arm', by Hwang and Markert, 1994, Ap. J., 431, p. 819). Hwang's earlier analysis of this data became part of her PhD thesis ( 'X-ray Studies of Supernova Remnants', February 1994, MIT). A copy of the Hwang and Markert paper is appended. The results of the study are well-summarized in the Hwang and Markert paper: the best spatial-spectral X-ray study yet made of the intriguing SNR G296.1-0.7 was obtained. This study showed interesting spectral variations over the surface of the object.It was also determined the gross physical properties of G296 based on its X-ray emission. Four other fields were also examined. For three of these the upper limits to the radio object were determined, and in one case found a weak, but statistically significant X-ray object coincident with the peak of the radio flux.

Markert, Thomas

1994-01-01

137

Fermi Large Area Telescope Detection of Supernova Remnant RCW 86  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

138

OXYGEN-RICH SUPERNOVA REMNANT IN THE LARGE MAGELLANIC CLOUD  

NASA Technical Reports Server (NTRS)

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

2002-01-01

139

New High-Resolution Radio Observations of the Supernova Remnant CTB 80  

NASA Astrophysics Data System (ADS)

We report new high-resolution and high-sensitivity radio observations of the extended supernova remnant (SNR) CTB 80 (G69.0+2.7) at 240, 324, 618, and 1380 MHz. The imaging of CTB 80 at 240 and 618 MHz was performed using the Giant Metrewave Radio Telescope in India. The observations at 324 and 1380 MHz were obtained using the Very Large Array of the National Radio Astronomy Observatory in its C and D configurations. The new radio images reveal faint extensions for the asymmetric arms of CTB 80. The arms are irregular, with filaments and clumps of size 1' (or 0.6 pc at a distance of 2 kpc). The radio image at 1380 MHz is compared with IR and optical emission. The IR-radio correspondence is excellent along the north arm of CTB 80. Ionized gas observed in the [S II] line perfectly matches the west and north edges of CTB 80. The central nebula associated with the pulsar PSR B1951+32 was investigated with an angular resolution of 10"×6". The new radio image obtained at 618 MHz shows with superb detail structures in the 8'×4' east-west ``plateau'' nebula that hosts the pulsar on its western extreme. A twisted filament, about 6' in extent (~3.5 pc), trails behind the pulsar in an approximate west-east direction. In the bright ``core'' nebula (size~45"), located to the west of the plateau, the images show a distortion in the morphology toward the west; this feature corresponds to the direction in which the pulsar escapes from the SNR with a velocity of ~240 km s-1. Based on the new observations, the energetics of the SNR and of the pulsar wind nebula are investigated.

Castelletti, G.; Dubner, G.; Golap, K.; Goss, W. M.; Velázquez, P. F.; Holdaway, M.; Rao, A. Pramesh

2003-11-01

140

A high sensitivity search for X-rays from supernova remnants in Aquila  

NASA Technical Reports Server (NTRS)

A high sensitivity scan of the galactic plane was performed to search for 2-20 keV X-rays from supernova remnants. The spectra of five X-ray sources detected between 44 deg and 31 deg longitude, of which only two might be associated with suggested supernova remnants, are reported on. Upper limits are presented for the 19 possible supernova remnants scanned in this survey.

Schwartz, D. A.; Bleach, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

1972-01-01

141

A high-sensitivity search for X-rays from supernova remnants in Aquila.  

NASA Technical Reports Server (NTRS)

A high-sensitivity scan of the galactic plane from 70 to 30 deg was performed to search for 2-20-keV X rays from supernova remnants. The spectra of five X-ray sources detected between 44 and 31 deg longitude are presented, of which only two might be associated with suggested supernova remnants. Upper limits are given for the 19 possible supernova remnants scanned.

Schwartz, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Bleach, R. D.

1972-01-01

142

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

NASA Astrophysics Data System (ADS)

significant, brightening and softening of the PWN's spectrum between the 2000 and 2006 data. The observed X-ray brightening and softening of the pulsar suggests for the first time that this HBP is revealing itself as a magnetar. The Chandra variability was also independently found by Gavriil et al. (2008) and Ng et al. (2008), and the magnetar nature of the pulsar was further established by Gavriil et al. (2008) using RXT E.

Safi-Harb, Samar

143

Observation of Nonthermal Emission from the Supernova Remnant IC443 with RXTE  

NASA Technical Reports Server (NTRS)

In this paper we present analysis of X-ray spectra from the supernova remnant IC443 obtained using the PCA on RXTE. The spectra in the 3 - 20 keV band are well fit by a two-component model consisting of thermal and nonthermal components. We compare these results with recent results of other X-ray missions and discuss the need for a cut-off in the nonthermal spectrum. Recent Chandra and XMM-Newton observations suggest that much of the nonthermal emission from IC443 can be attributed to a pulsar wind nebula. We present the results of our search for periodic emission in the RXTE PCA data. We then discuss the origin o f the nonthermal component and its possible association with the unidentified EGRET source.

Sturner, S. J.; Keohane, J. W.; Reimer, O.

2002-01-01

144

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

145

MHD interaction of pulsar wind nebulae with SNRs and with the ISM  

NASA Astrophysics Data System (ADS)

In the late 1960s the discovery of the Crab pulsar in its associated supernova remnant, launched a new field in supernova remnant research: the study of pulsar-powered or plerionic supernova remnants. In these type of remnants, the relativistic wind emitted by the pulsar, blows a pulsar wind nebula into the interior of its supernova remnant. Now, more then forty years after the discovery of the Crab pulsar, there are about a hundred plerionic supernova remnants known, due to the ever-increasing capacity of observational facilities. These observational studies reveal a Zoo of complex morphologies over a wide range of frequencies, indicating the significance of the interaction between a pulsar wind nebula with its surrounding supernova remnant. A pulsar which gained a kick velocity at birth, will ultimately break outside of its remnant, after which the pulsar wind nebula interacts directly with the interstellar medium. In general these pulsar wind nebulae are bounded by a bow shock, due to the supersonic motion of the pulsar. There are a few examples known of these pulsar-powered bow shocks, a number which is slowly increasing. I will first discuss the different evolutionary stages of a pulsar wind nebula which is interacting with its associated supernova remnant. Next I will discuss pulsar wind nebulae which are interacting directly with the interstellar medium. For both cases I will review some of the recent (M)HD models of pulsar wind nebulae, and connect these models with observational studies. In the first case this connection allows for the determination of the evolutionary stage for some of the observed plerionic supernova remnants. In the second case this connection allows to infer several properties of the pulsar, the observed pulsar-powered bow shock and the surrounding medium itself.

van der Swaluw, E.

146

Distant Supernova Remnant Imaged by Chandra's High Resolution Camera  

NASA Astrophysics Data System (ADS)

The High Resolution Camera (HRC), one of the two X-ray cameras on NASA's Chandra X-ray Observatory, was placed into the focus for the first time on Monday, August 30. The first target was LMC X-1, a point-like source of X rays in the Large Magellanic Cloud. The Large Magellanic Cloud, a companion galaxy to the Milky Way, is 160,000 light years from Earth. After checking the focus with LMC X-1, Chandra observed N132D, a remnant of an exploded star in the Large Magellanic Cloud. "These were preliminary test observations," emphasized Dr. Stephen Murray, of the Harvard-Smithsonian Center for Astrophysics, principal investigator for the High Resolution Camera. "But we are very pleased with the results. All indications are that the HRC will produce X-ray images of unprecedented clarity." The N132D image shows a highly structured remnant, or shell, of 10-million-degree gas that is 80 light years across. Such a shell in the vicinity of the Sun would encompass more than fifty nearby stars. The amount of material in the N132D hot gas remnant is equal to that of 600 suns. The N132D supernova remnant appears to be colliding with a giant molecular cloud, which produces the brightening on the southern rim of the remnant. The molecular cloud, visible with a radio telescope, has the mass of 300,000 suns. The relatively weak x-radiation on the upper left shows that the shock wave is expanding into a less dense region on the edge of the molecular cloud. A number of small circular structures are visible in the central regions and a hint of a large circular loop can be seen in the upper part of the remnant. Whether the peculiar shape of the supernova remnant can be fully explained in terms of these effects, or whether they point to a peculiar cylindrically shaped explosion remains to be seen. -more- "The image is so rich in structure that it will take a while to sort out what is really going on," Murray said. "It could be multiple supernovas, or absorbing clouds in the vicinity of the supernova." The unique capabilities of the HRC stem from the close match of its imaging capability to the focusing power of the mirrors. When used with the Chandra mirrors, the HRC will make images that reveal detail as small as one-half an arc second. This is equivalent to the ability to read a stop sign at a distance of twelve miles. The checkout period for the HRC will continue for the next few weeks, during which time the team expects to acquire images of other supernova remnants, star clusters, and starburst galaxies. To follow Chandra's progress, visit the Chandra News Web site at: http://chandra.harvard.edu AND http://chandra.nasa.gov NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra X-ray Observatory for NASA's Office of Space Science, NASA Headquarters, Washington, D.C. The Smithsonian Astrophysical Observatory's Chandra X-ray Center in Cambridge, Mass., manages the Chandra science program and controls the observatory for NASA. TRW Space and Electronics Group of Redondo Beach, Calif., leads the contractor team that built Chandra. High resolution digital versions of the X-ray image (300 dpi JPG, TIFF) and other information associated with this release are available on the Internet at: http://chandra.harvard.edu/photo/0050/ or via links in: http://chandra.harvard.edu

1999-09-01

147

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

148

Molecular Environment of the Supernova Remnant IC 443: Discovery of the Molecular Shells Surrounding the Remnant  

NASA Astrophysics Data System (ADS)

We have carried out 12CO, 13CO, and C18O observations toward the mixed morphology supernova remnant (SNR) IC 443. The observations cover a 1.°5 × 1.°5 area and allow us to investigate the overall molecular environment of the remnant. Some northern and northeastern partial shell structure of CO gas is around the remnant. One of the partial shells, about 5' extending beyond the northeastern border of the remnant's bright radio shell, seems to just confine the faint radio halo. On the other hand, some faint CO clumps can be discerned along the eastern boundary of the faint remnant's radio halo. Connecting the eastern CO clumps, the northeastern partial shell structures, and the northern CO partial shell, we can see that a half molecular ring structure appears to surround the remnant. The LSR velocity of the half-ring structure is in the range of -5 km s-1 to -2 km s-1, which is consistent with that of the -4 km s-1 molecular clouds. We suggest that the half-ring structure of the CO emission at V LSR ~ -4 km s-1 is associated with the SNR. The structures are possibly swept up by the stellar winds of SNR IC 443's massive progenitor. Based on the Wide-field Infrared Survey Explorer and the Two Micron All Sky Survey near-IR database, 62 young stellar object (YSO) candidates are selected within the radio halo of the remnant. These YSO candidates concentrated along the boundary of the remnant's bright radio shell are likely to be triggered by the stellar winds from the massive progenitor of SNR IC 443.

Su, Yang; Fang, Min; Yang, Ji; Zhou, Ping; Chen, Yang

2014-06-01

149

XMM-Newton and Suzaku Observations of Vela Supernova Remnant Ejecta Fragments  

NASA Astrophysics Data System (ADS)

The Vela Supernova Remnant (SNR) is one of the nearest SNRs, subtending more than 8 degrees on the sky. Its environment is complex: the remnant is bright, soft, and sharply defined to the east and north, but much fainter and less well ordered in the west and south. Age estimates for the associated pulsar range from 11400 years to as much as 18000 years, making the the SNR a moderately old remnant. The discovery of protrusions beyond the projected rim suggested that these protrusions could be ejecta fragments (Aschenbach et al. 1995, Nature 373, 587), and subsequent X-ray observations by a number of workers confirmed enhanced abundances in a number of these fragments. We will present analyses of several ejecta fragments based on XMM-Newton and Suzaku X-ray observations. This will include an examination of the composition, morphology, structure of Vela Fragment ``D'', the largest and brightest of the fragments, and explore the possibility that the fragment consists of several components. This work was supported by NASA grants NNX06AE40G, NNX07AF67G, NNX08AZ74G, and by NASA contract NAS8-03060.

Gaetz, Terrance J.

2011-09-01

150

X-Ray Measured Dynamics of Tycho's Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

151

MHD interaction of pulsar wind nebulae with SNRs and with the ISM  

NASA Astrophysics Data System (ADS)

In the late 1960s the discovery of the Crab pulsar in its associated supernova remnant, launched a new field in supernova remnant research: the study of pulsar-driven or plerionic supernova remnants. In these type of remnants, the relativistic wind emitted by the pulsar, blows a pulsar wind nebula into the interior of its supernova remnant. Now, more then forty years after the discovery of the Crab pulsar, there are more then fifty plerionic supernova remnants known, due to the ever-increasing capacity of observational facilities. These observational studies reveal a Zoo of complex morphologies over a wide range of frequencies, indicating the significance of the interaction between a pulsar wind nebula with its surrounding supernova remnant. A pulsar which gained a kick velocity at birth, will ultimately break outside of its remnant, after which the pulsar wind nebula interacts directly with the interstellar medium. In general these pulsar wind nebulae are bounded by a bow shock, due to the supersonic motion of the pulsar. There are a few examples known of these pulsar-powered bow shocks, a number which is slowly increasing. I will review our current understanding of the different evolutionary stages of a pulsar wind nebula as it is interacting with its associated supernova remnant. Therefore, I will discuss both analytical and more recent numerical (M)HD models. The four main stages of a pulsar wind nebula are: the supersonic expansion stage, the reverse shock interaction stage, the subsonic expansion stage and ultimately the stage when the head of the bubble is bounded by a bow shock, due to the supersonic motion of the pulsar. Ultimately this pulsar wind nebula bow shock will break through its associated remnant, after which the pulsar-powered bow shock will interact directly with the interstellar medium. I will discuss recent numerical models from these type of pulsar wind nebulae and their morphology.

van der Swaluw, E.

152

Three-Dimensional Kinematics of Core-Collapse Supernova Remnants approaching Middle Age  

NASA Astrophysics Data System (ADS)

The Galactic supernova remnants (SNRs) Puppis A and G292.0+1.8 have long been known to have optical knots composed almost entirely of heavy elements (especially oxygen) with Doppler velocities 1000 km/s or higher--fragments from the progenitor core that were launched in the explosion and have only recently been excited. Both harbor young pulsars near their centers. These SNRs are similar to Cas A but larger, with less extreme velocities, and thus are presumably older. Using CCD images from epochs 1986-2008, we have measured proper motions for over 60 knots in each of these SNRs, and in both cases we find motions proportional to displacement from an expansion center, indicating free expansion. The expansion rates for both SNRs give kinematic ages 3000 yr--almost 10 times the age of Cas A. We have also obtained spectra from many of these and other knots, and have combined the radial and transverse velocities to give the first 3-dimensional models for the ejecta distribution. For G292 the ejecta are concentrated primarily in broad bi-conical jets, oriented roughly N-S in the plane of the sky. Based on its position, the pulsar should be moving nearly perpendicular to the jet axis. Puppis A shows a more complicated structure; many of its knots have strong [N II] and/or [S II] lines in addition to those from O, and with similar high velocities. The fast knots are concentrated in three complexes, all in the NE quadrant of the remnant, while the pulsar has been measured as recoiling at high velocity toward the SW. We will discuss these results and their possible implications for understanding core-collapse SNe. Supported in part by NSF grant AST-0908566.

Winkler, P. Frank; Garber, J. H.; Plunkett, A. L. D.; Twelker, K.; Long, K. S.

2010-02-01

153

No cold dust within the supernova remnant Cassiopeia A.  

PubMed

A large amount (about three solar masses) of cold (18 K) dust in the prototypical type II supernova remnant Cassiopeia A was recently reported. It was concluded that dust production in type II supernovae can explain how the large quantities (approximately 10(8) solar masses) of dust observed in the most distant quasars could have been produced within only 700 million years after the Big Bang. Foreground clouds of interstellar material, however, complicate the interpretation of the earlier submillimetre observations of Cas A. Here we report far-infrared and molecular line observations that demonstrate that most of the detected submillimetre emission originates from interstellar dust in a molecular cloud complex located in the line of sight between the Earth and Cas A, and is therefore not associated with the remnant. The argument that type II supernovae produce copious amounts of dust is not supported by the case of Cas A, which previously appeared to provide the best evidence for this possibility. PMID:15577902

Krause, Oliver; Birkmann, Stephan M; Rieke, George H; Lemke, Dietrich; Klaas, Ulrich; Hines, Dean C; Gordon, Karl D

2004-12-01

154

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

155

Young Supernova Remnant Candidates in the Southern Hemisphere  

NASA Astrophysics Data System (ADS)

Studies of the youngest supernova remnants (SNRs) provide the tantalizing opportunity to probe the circumstellar environment of their progenitor; to study the details of the explosive process; and to examine the efficiency of cosmic ray acceleration by shocks. We present detailed radio observations of four SNR candidates which, based upon their angular scale, could be the youngest in the Galaxy. To provide a more complete picture of the nature of these sources and their environments, we will present our radio data along with multi-wavelength data from various surveys.

Robbins, William; Moss, V.; Gaensler, B. M.; Murphy, T.; Green, A. J.

2012-01-01

156

The Unusual Young Supernova Remnant Population in M83  

NASA Astrophysics Data System (ADS)

The face-on grand design spiral galaxy M83 (d=4.6 Mpc) is a veritable supernova factory, having generated six known SNe in less than 100 years. Hence, one might expect of order 60 or more supernova remnants (SNRs) less than a thousand years old that might shed light on the poorly understood ejecta-dominated phase of early SNR evolution, as well as many more older, ISM-dominated remnants that should still be visible. We are conducting a multi-wavelength Chandra/Hubble/ground-based campaign to find and characterize the SNRs in M83, concentrating especially on the younger population. HST/WFC3 emission-line data for seven fields covering the bulk of the bright optical disk have allowed us to identify ~50 optical SNR candidates with angular sizes below 0.5” (<11 pc), many with corresponding Chandra X-ray counterparts. However, with the singular exception of the remnant of SN1957D, we are not finding the expected population of ejecta-dominated young SNRs. Rather, most of the young SNRs appear to have quickly evolved into the radiative phase. Gemini-S GMOS spectra of selected objects confirm the lack of observed high velocities or obvious ejecta-enhancement of abundances. This unexpected result implies that the CSM/ISM environments for most young remnants in M83 are very dense, perhaps due in part to the super-solar metal abundances in much of this galaxy. We will show representative data from all relevant data sets that lead us to this conclusion. This work is supported in part by STScI grant HST-GO-12513.01-A and Chandra grant SAO-GO1-12115C to Johns Hopkins University.

Blair, William P.; Dopita, M. A.; Ghavamian, P.; Kuntz, K. D.; Long, K. S.; Plucinsky, P. P.; Soria, R.; Winkler, P. F.

2014-01-01

157

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

158

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

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

159

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

National Technical Information Service (NTIS)

We report observation of the supernova remnant 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 supernova remnant with mixed morphology located of...

A. A. Abdo B. M. Baughman D. Bastieri G. Barbiellini J. Ballet K. Bechtol L. Baldini M. Ackermann M. Ajello

2012-01-01

160

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

161

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

NASA Astrophysics Data System (ADS)

We report the results of a 8000 s observation of the supernova remnant W44 using the ROSAT Position Sensitive Proportional Counter (PSPC). The image shows the same centrally peaked morphology observed by the Einstein IPC and contrasts with the shell-like radio morphology. The eastern limb shows a lack of X-ray emission within the radio shell, probably due to the interaction between the Supernova Remnants (SNR) and a molecular cloud. No counterpart to the pulsar 1853 + 01 in W44 has been detected, with LX less than 1.3 x 1032 ergs/s in the 0.2 to 2.4 keV band. The spectral analysis of the central part of W44, combining EXOSAT ME and Einstein SSS data, shows that the shocked plasma has not reached ionization equilibrium. The best nonequilibrium fit to PSPC, ME, and SSS spectra gives Eta = 1051 ergs cm-6, Ts = 107 K with Te = Ti, suggesting conditions are approaching ionization equilibrium. There is no evidence of enhanced abundances of Mg, Si, S, or Fe. The variation of temperature and column density was obtained region by region using the PSPC and Einstein IPC. The temperature is largely uniform over the remnant, but strong column density variations are found to be consistent with molecular clouds in the line of sight. An evaporation model with a two-phase interstellar medium structure of clumps and interclump gas (White & Long 1991) can explain the X-ray centrally peaked morphology of W44. The clumps remaining behind a SN shock provide a reservoir of material, and evaporat e to increase the density of X-ray emitting gas in the interior of a SNR. The uniform temperature distribution of W44 strongly supports the predictions of this model. In addition, mosaiced H alpha and (S II) images of W44, taken using the prime focus universal extragalactic instrument (PFUEI) camera on the Palomar 60 sec telescope, reveal the first discovery of optical filaments (both H alpha and (S II)) in the northwestern and southeastern portion of the remnant, within the X-ray emitting region. The optical filaments and the X-ray image showing locally brighter emission and clumps along the filaments suggest both are produced by the interaction between the supernova shock front and regions of enhanced ambient density.

Rho, Jeonghee; Petre, R.; Schlegel, Eric M.; Hester, J. Jeff

1994-08-01

162

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

NASA Astrophysics Data System (ADS)

In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. In particular, at high energies we assume that D(E)proptoE?, with ? = 1/3 and ? = 0.6 being the reference scenarios. The large scale distribution of supernova remnants in the Galaxy is modeled following the distribution of pulsars, with and without accounting for the spiral structure of the Galaxy. We find that the stochastic fluctuations induced by the spatial and temporal distribution of supernovae, together with the effect of spallation of nuclei, lead to mild but sensible violations of the simple, leaky-box-inspired rule that the spectrum observed at Earth is N(E)proptoE-? with ? = ?+?, where ? is the slope of the cosmic ray injection spectrum at the sources. Spallation of nuclei, even with the small rates appropriate for He, may account for small differences in spectral slopes between different nuclei, possibly providing an explanation for the recent CREAM observations. For ? = 1/3 we find that the slope of the proton and helium spectra are ~ 2.67 and ~ 2.6 respectively (with fluctuations depending on the realization of source distribution) at energies around ~ 1 TeV (to be compared with the measured values of 2.66±0.02 and 2.58±0.02). For ? = 0.6 the hardening of the He spectra is not observed. The stochastic effects discussed above cannot be found in ordinary propagation calculations, such as GALPROP, where these effects and the point like nature of the sources are not taken into account. We also comment on the effect of time dependence of the escape of cosmic rays from supernova remnants, and of a possible clustering of the sources in superbubbles. In a second paper we will discuss the implications of these different scenarios for the anisotropy of cosmic rays.

Blasi, Pasquale; Amato, Elena

2012-01-01

163

Simulations of Supernova Remnants in Diffuse Media. II. Three Remnants and Their X-Ray Emission  

Microsoft Academic Search

This paper provides detailed descriptions of the X-ray emission from supernova remnants (SNRs) evolving in warm, low-density, nonthermal pressure-dominated regions (T_0=10^4 K, n=0.001 cm^-3, P_nt=1800 or 7200 K cm^-3). Nonequilibrium ionization hydrocode simulations are used to predict the high-resolution spectra, 1\\/4 and 3\\/4 keV ROSAT PSPC count rates, spatial appearance, color temperatures, and ratios of O VII to O VIII

R. L. Shelton

1999-01-01

164

The MIPSGAL View of Supernova Remnants in the Galactic Plane  

NASA Astrophysics Data System (ADS)

We report the detection of Galactic supernova remnants (SNRs) in the mid-infrared (at 24 and 70 ?m), in the coordinate ranges 10° < l < 65° and 285° < l < 350°, |b| < 1°, 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 8/F 24] versus [F 70/F 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 ?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 ?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 ?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 Gonçalves, D.; Noriega-Crespo, A.; Paladini, R.; Martin, P. G.; Carey, S. J.

2011-08-01

165

Hubble Space Telescope Image, Supernova Remnant Cassiopeia A  

NASA Technical Reports Server (NTRS)

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

2000-01-01

166

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

NASA Technical Reports Server (NTRS)

It is shown that only a small fraction of the many supernovae in the Galaxy produces observable supernova remnants; this fraction, which is found to depend weakly on the lower mass limit of the SN progenitors, and more strongly on the specific characteristics of the associated interstellar medium, decreases from about 15% near the galactic center to 10% at R(gal) of about 10 kpc and drops nearly to zero for R(gal) greater than 15 kpc. Whether an SNR is detectable is determined by the density of the ambient interstellar medium in which it is embedded; it is found that SNRs are detectable only above some critical density (about 0.1 per cu cm). The presence of large low-density superbubble cavities around stellar associations due to the combined effects of stellar winds and supernova shells strongly suggests that a large portion of the detectable SNRs must have runaway stars as their progenitors.

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

1980-01-01

167

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

SciTech Connect

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

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

2013-09-10

168

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

169

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

170

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

SciTech Connect

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

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

2013-06-20

171

SN1987A: The Birth of a Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

McCray, Richard

2003-01-01

172

High-Resolution Polarimetry of Supernova Remnant Kesteven 69  

NASA Astrophysics Data System (ADS)

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

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

2008-06-01

173

Observations and discoveries of supernova remnants with GMRT  

NASA Astrophysics Data System (ADS)

We have measured HI absorption distance to the youngest Galactic supernova remnant G1.9+0.3. Absorption by known anomalous velocity features near the Galactic centre (GC) puts a lower limit on its distance from Sun as 10 kpc, 2 kpc further away from the GC. We have found a small diameter (1.6') shell like structure G354.4+0.0, that shows polarised emission in the NVSS. Based on its morphology, angular size, HI distance and its spectrum between 1.4 GHz and 330 MHz, it is perhaps the second youngest SNR in the Galaxy that is expanding in a dense environment of an HII region surrounding it. Our pilot observation of the inner Galactic 4th quadrant within 337° < l < 354° with a fixed Galactic latitude of 0.37° has confirmed G345.1-0.2 as an SNR.

Roy, Subhashis; Pal, Sabyasachi

2014-01-01

174

Multi-band Observation of TeV Supernova Remnants  

NASA Astrophysics Data System (ADS)

We study several TeV Supernova Remnants (SNRs W51C, CTB 37A, CTB 37B and G353.6-0.7) by radio and X-ray observations. We utilize neutral hydrogen (\\HI) 21 cm line data to measure their kinematic distances, and use the CO line survey sensitive to molecular hydrogen clouds to validate these distance measurements and understand their relation to the TeV SNRs. Our study show that the TeV ?-ray emission from W51C should not be associated with the high-velocity HI clouds; CTB 37A and CTB 37B are at different distances and are only by chance nearby each other on the sky; the extended TeV emission from G353.6-0.7 possibly originates from the interaction between the SNR shock and the adjacent CO clouds.

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

2014-01-01

175

Spitzer Space Telescope Spectroscopy of the Kepler Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

Roellig, T. L.; Onaka, T.

2004-01-01

176

Phosphorus in the young supernova remnant Cassiopeia A.  

PubMed

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

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

2013-12-13

177

Methanol masers in Galactic center region supernova remnants  

NASA Astrophysics Data System (ADS)

Methanol masers can be used to constrain densities and estimate kinematical distances to supernova remnants (SNRs), important parameters in cosmic ray acceleration models. With the goal of testing those models both for SNRs inside and outside the Galactic center (GC) region, we have used the Very Large Array to search for 36 GHz and 44 GHz methanol lines in Galactic SNRs. We report on the overall results of the maser search, and in particular the results of the GC SNR G1.4-0.1 in which more than 40 masers were found. They may be due to interactions between the SNR and at least two separate molecular clouds. Methanol masers were also detected in W28 and in Sgr A East.

Pihlström, Y. M.; McEwen, B. C.; Sjouwerman, L. O.

2014-05-01

178

Supernova Remnants in the Most Fertile Galaxy: NGC 6946  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

179

Infrared [Fe II] and Dust Emissions from Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) are strong thermal emitters of infrared radiation. The most prominent lines in the near-infrared spectra of SNRs are [Fe II] lines. The [Fe II] lines are from shocked dense atomic gases, so they trace SNRs in dense environments. After briefly reviewing the physics of the [Fe II] emission in SNR shocks, I describe the observational results which show that there are two groups of SNRs bright in [Fe II] emission: middle-aged SNRs interacting with molecular clouds and young core-collapse SNRs in dense circumstellar medium. The SNRs belonging to the former group are also bright in near-infrared H2 emission, indicating that both atomic and molecular shocks are pervasive in these SNRs. The SNRs belonging to the latter group have relatively small radii in general, implying that most of them are likely the remnants of SN IIL/b or SN IIn that had strong mass loss before the explosion. I also comment on the ``[Fe II]-H2 reversal'' in SNRs and on using the [Fe II]-line luminosity as an indicator of the supernova (SN) rate in galaxies. In the mid- and far-infrared regimes, thermal dust emission is dominant. The dust in SNRs can be heated either by collisions with gas species in a hot plasma or by radiation from a shock front. I discuss the characteristics of the infrared morphology of the SNRs interacting with molecular clouds and their dust heating processes. Finally, I give a brief summary of the detection of SN dust and crystalline silicate dust in SNRs.

Koo, Bon-Chul

2014-01-01

180

Life after stellar death: Planetary Nebulae and Supernova Remnants  

NASA Astrophysics Data System (ADS)

Planetary nebulae (PNe) are powerful tracers of our Galaxy's star formation history. Their study can provide insight to the late stages of stellar evolution, the nucleosynthesis in low and intermediate mass stars (1-8Mo) and the chemical evolution of galaxies. Supernova explosions belong to the most spectacular events in the Universe. Supernova remnants (SNRs), which are the consequent results of these events and come from the late stages of massive stars (>8Mo), are among the strongest radio sources observed. They have a major influence on both the properties of the interstellar medium (ISM) and the evolution of galaxies as a whole. They enrich the ISM with heavy elements, release about 1051 ergs of energy, heat the ISM, compress the magnetic field, and efficiently accelerate, by their shock waves, energetic cosmic rays observed throughout the Galaxy. I will present results of our work on PNe and SNRs, which aims to (a) discover optical SNRs in the Galaxy, (b) study their morphology and kinematics, (c) characterize their properties (such as density, shock velocity etc.) and (d) provide information on their interaction with the ISM, using the "Aristarchos" among other telescopes.

Boumis, P.

2013-09-01

181

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

182

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

183

ROSAT HRI observations of Magellanic Cloud supernova remnants  

NASA Technical Reports Server (NTRS)

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

Hughes, John P.

1994-01-01

184

Gamma-rays from supernova remnants and the signatures of diffusive shock acceleration  

NASA Technical Reports Server (NTRS)

A nonlinear shock acceleration model which generates non-thermal proton distributions and includes a self-consistent determination of shock hydrodynamics, is considered. Gamma ray spectra are obtained for supernova remnants, allowing for the cessation of acceleration to high energies due to the finite ages and the sizes of the remnants. Gamma ray spectral cutoffs can be observed in the TeV range for reasonable remnant parameters and deviations from power law behavior are found at all energies from 1 MeV to cutoff. Correlated observations by the International Gamma Ray Astrophysics Laboratory, Whipple and other instruments may provide stringent constraints to understanding supernova remnants.

Baring, Matthew G.; Ellison, Donald C.; Grenier, Isabelle

1997-01-01

185

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

186

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

187

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

188

32 GHz radio continuum observations of four shell-type supernova remnants  

Microsoft Academic Search

A series of 32-GHz maps obtained with the Effelsberg 100-m telescope of the four supernova remnants G11.2-0.3, G29.7-0.3, G41.1-0.3 and G43.3-0.2 is presented. The radio spectra of these sources are discussed. G11.2-0.3 seems to belong to the class of supernova remnants showing both shell-type and plerionic characteristics.

H. W. Morsi; W. Reich

1987-01-01

189

On the characteristics of line emissions from binary X-ray sources and supernova remnants  

Microsoft Academic Search

The paper considers the characteristics of line emissions from binary X-ray sources and supernova remnants. X-ray spectroscopy of celestial X-ray sources can yield useful data on physical conditions and processes responsible for emission from binary X-ray sources; iron line emission at about 6.8 keV from many supernova remnants and X-ray binaries has been observed and the available data on iron

T. M. K. Marar; V. S. Iyengar; K. Kasturirangan; U. R. Rao

1979-01-01

190

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

191

A multiwavelength study of Cassiopeia A and Kepler's supernova remnants  

NASA Astrophysics Data System (ADS)

A multiwavelength comparison of X-ray, infrared, optical, and radio images for Cassiopeia A (Cas A) and Kepler's supernova remnants has been conducted to construct a coherent physical picture of the multiple interacting thermal and relativistic plasmas. In addition, high- resolution X-ray proper motions of compact features in Cas A have been measured over a two-year baseline. The X-ray emission in Cas A can be separated into four spectrally and kinematically distinct classes that have clear associations to the emission in the other three wavebands. The emitting material is classified into two components—shocked circumstellar medium (CSM) and shocked ejecta, which show the same respective morphologies and proper motions in the different bands. In the shocked CSM, we find matched low-energy enhanced X-ray emission and optical quasi-stationary flocculi, and X-ray continuum-dominated emission matched with filamentary radio structures. We also find hybrid X-ray low-energy-enhanced/continuum-dominated emission matched to 24?m dust emission in the CSM. In the shocked ejecta, we find matched silicon and iron dominated X-ray emission and optical fast-moving knots. Based on the kinematic and morphological results, we propose evolutionary scenarios for the ejecta and circumstellar material in Cas A. In Kepler's supernova remnant, we also find clear associations between the emission in the four wavebands. The ejecta are defined by matching steep-spectrum radio emission and X-ray emission. The forward shock is identified by a ring of continuum-dominated X-ray emission, flat-spectrum radio emission, and filamentary optical Balmer-dominated emission. The clumpy circumstellar medium is identified by knotty optical emission, mid-infrared dust emission, and some matching X-ray emission. To the south the forward and reverse shocks have separated, whereas to the north there is little separation. There is an anti-correlation between the flat-spectrum radio synchrotron emission and the thermal emission to the north suggesting a relative weakening of the particle acceleration at the forward shock due to Alvén wave damping.

Delaney, Tracey Ann

192

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

193

Interstellar and Ejecta Dust in the Cas A Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

194

ALEXIS Observations of the Monogem Ring Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

Plucinsky, Paul; West, Donald (Technical Monitor)

2001-01-01

195

RADIO POLARIMETRY SIGNATURES OF STRONG MAGNETIC TURBULENCE IN SUPERNOVA REMNANTS  

SciTech Connect

We discuss the emission and transport of polarized radio-band synchrotron radiation near the forward shocks of young shell-type supernova remnants, for which X-ray data indicate a strong amplification of turbulent magnetic field. Modeling the magnetic turbulence through the superposition of waves, we calculate the degree of polarization and the magnetic polarization direction which is at 90 deg. to the conventional electric polarization direction. We find that isotropic strong turbulence will produce weakly polarized radio emission even in the absence of internal Faraday rotation. If anisotropy is imposed on the magnetic-field structure, the degree of polarization can be significantly increased, provided internal Faraday rotation is inefficient. Both for shock compression and a mixture with a homogeneous field, the increase in polarization degree goes along with a fairly precise alignment of the magnetic-polarization angle with the direction of the dominant magnetic-field component, implying tangential magnetic polarization at the rims in the case of shock compression. We compare our model with high-resolution radio polarimetry data of Tycho's remnant. Using the absence of internal Faraday rotation we find a soft limit for the amplitude of magnetic turbulence, {delta}B {approx}< 200 {mu}G. The data are compatible with a turbulent magnetic field superimposed on a radial large-scale field of similar amplitude, {delta}B {approx_equal} B {sub 0}. An alternative viable scenario involves anisotropic turbulence with stronger amplitudes in the radial direction, as was observed in recent Magnetohydrodynamics simulations of shocks propagating through a medium with significant density fluctuations.

Stroman, Wendy; Pohl, Martin [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)], E-mail: mkp@iastate.edu

2009-05-10

196

A Multiwavelength Database of Magellanic Cloud Supernova Remnants  

NASA Astrophysics Data System (ADS)

Supernovae (SNe), through their diffuse supernova remnants (SNRs), are primarily responsible for the injection of energy and heavy elements into the interstellar medium (ISM). SNe provide most of the hot gas component of the ISM, and through collective inputs to structures such as superbubbles and supergiant shells, can transfer hot gas into a galaxy halo. The energy and heavy elements influence future generations of star formation in a galaxy and have a profound effect on galaxy evolution. We have undertaken a long-term multiwavelength study of SNRs in the Magellanic Clouds (MCs). These galaxies contain extraordinary samples of SNRs at a wide variety of types, ages, evolutionary stages, and environments. The known, common distances and low obscuration of the MCs allows their SNRs to be studied as members of an increasingly well-understood population. The current generation of instruments, including the Chandra and XMM X-ray satellites and the Hubble and Spitzer Space Telescopes, have allowed high-resolution examinations of these SNRs at levels comparable to those for Galactic objects. Crucially, new surveys of the MCs with the Australia Telescope Compact Array in radio, and the Magellanic Clouds Emission-Line Survey at CTIO, have providded a wealth of data on each of these objects. We have used these resources to build up a database of information on the Magellanic Cloud SNRs, in order to make the data and findings easily accessible to other researchers. We here present the current state of the database and future plans for the inclusion of more information. The authors thank NASA's LTSA grant NNX08AM54G for support of this long-term project.

Murphy Williams, Rosa Nina; Dickel, J. R.; Chu, Y.; Points, S.; Winkler, F.; Johnson, M.; Lodder, K.

2010-01-01

197

Supernova 1987A Interpreted through the SLIP Pulsar Model  

NASA Astrophysics Data System (ADS)

The model of pulsar emission through superluminally induced polarization currents (SLIP) predicts that pulsations produced by such currents, induced by a rotating, magnetized body at many light cylinder radii, as would be the case for a neutron star born within any star of >1.5 solar masses, will drive pulsations close to the axis of rotation. Such highly collimated pulsations (<= 1 in 10,000), and the similarly collimated jets of particles which it drove, including 1e-6 solar masses with velocities of up to 0.95 c, were responsible for the features of its very early light curve (days 3 - 20), the "Mystery Spot," observed slightly later (days 30 - 50 and >), and later, in less collimated form, the bipolarity of SN 1987A itself. The pulsations and jet interacted with circumstellar material (CM), to produce features observed in the very early light curve which correspond to: 1) the entry of the pulsed beam into the CM; 2) the entry of the 0.95 c particles into the CM; 3) the exit of the pulsed beam from the CM (with contributions in the B and I bands -- the same as later inferred/observed for its 2.14 ms pulsations); and 4) the exit of the fastest particles from the CM. Because of the energy requirements of the jet in these early stages, the spindown required of its pulsar could exceed 1e-5 Hz/s at a rotation rate of 500 Hz. There is no reason to suggest that this mechanism is not universally applicable to all SNe with gaseous remnants remaining, and thus SN 1987A is the Rosetta Stone for 99% of SNe, gamma-ray bursts, and millisecond pulsars. This work was supported in part by the Department of Energy through the Los Alamos Directed Research Grant DR20080085.

Middleditch, John

2010-01-01

198

SUPERNOVA REMNANTS AND STAR FORMATION IN THE LARGE MAGELLANIC CLOUD  

SciTech Connect

It has often been suggested that supernova remnants (SNRs) can trigger star formation. To investigate the relationship between SNRs and star formation, we have examined the known sample of 45 SNRs in the Large Magellanic Cloud (LMC) to search for associated young stellar objects (YSOs) and molecular clouds. We find seven SNRs associated with both YSOs and molecular clouds, three SNRs associated with YSOs but not molecular clouds, and eight SNRs near molecular clouds but not associated with YSOs. Among the 10 SNRs associated with YSOs, the association between the YSOs and SNRs either can be rejected or cannot be convincingly established for eight cases. Only two SNRs have YSOs closely aligned along their rims; however, the time elapsed since the SNR began to interact with the YSOs' natal clouds is much shorter than the contraction timescales of the YSOs, and thus we do not see any evidence of SNR-triggered star formation in the LMC. The 15 SNRs that are near molecular clouds may trigger star formation in the future when the SNR shocks have slowed down to <45 km s{sup -1}. We discuss how SNRs can alter the physical properties and abundances of YSOs.

Desai, Karna M.; Chu, You-Hua; Gruendl, Robert A.; Dluger, William; Katz, Marshall; Wong, Tony; Looney, Leslie W. [Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States); Chen, C.-H. Rosie [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Hughes, Annie [Centre for Supercomputing and Astrophysics, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia); Muller, Erik [Department of Physics and Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Ott, Juergen [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Pineda, Jorge L. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States)

2010-08-15

199

HST/ACS Narrowband Imaging of the Kepler Supernova Remnant  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

200

Supernova Remnants in the Multi-wavelength Era  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) influence and probe the properties of the gas and dust that compose the interstellar medium (ISM) into which they are born -- the ISM from which other stars and planets may form. The increasing prevalence of sensitive, high-resolution, large-scale surveys offers an avenue to progress our understanding of SNRs, more accurately count sources, and more precisely constrain the stellar contribution to the ISM of the Milky Way. Here I will outline a few case studies in which data from multiple wavebands are brought to bare on issues of source classification, environment, morphology, and evolutionary phase. In examining just these few cases, I find a misclassified SNR, a pair whose unusual morphologies can be explained by a partial transition to the radiative phase, and provide further insight into a set of SNR candidates which, if confirmed, may be amongst the youngest in the Galaxy. These examples demonstrate the potential of including existing multi-wavelength data in the analysis of SNRs.

Robbins, William; Gaensler, B. M.; Murphy, T.; Reeves, S.; Moss, V.; Green, A. J.

2013-01-01

201

A XMM Survey for Compact Objects in Supernova Remnants  

NASA Technical Reports Server (NTRS)

The goal of the project is to identify candidate neutron stars in Galactic supernova remnants (SNRs) through their X-ray emission. With XMM we observed the SNRs and typically find 10 - 50 X-ray sources. Almost all are either background galaxies or foreground stars. Therefore we must also pursue detailed optical/infrared follow-up observations to find counterparts for these X-ray sources and classify them. At the depth of the XMM observations, practically all confusing X-ray sources should have identifiable optical/IR counterparts. We have done a preliminary analysis of the XMM data and identified likely counterparts to the X-ray sources from available surveys(DSS, 2MASS). We then obtained wide-field optical/IR data from Palomar to get counterparts for the remaining sources. This analysis is underway: while often a single bright source is in the XMM error circle and can be considered a counterpart, in a number of cases we must do more detailed studies and evaluate several fainter optical/lR sources. We hope to have the final analysis of the XMM + Palomar data done this Fall. It is possible that additional, deeper optical/IR data may be necessary. We expect to publish our results by the end of this year.

Kulkarni, Shrinivas R.

2004-01-01

202

The high energy X-ray spectra of supernova remnants  

NASA Technical Reports Server (NTRS)

The results of fitting an ionization-nonequilibrium (INE) model to the high-energy (above 5-keV) X-ray spectra of the young supernova remnants Cas A and Tycho are presented. As an additional constraint, the models must simultaneously fit lower-energy, higher-resolution data. For Cas A, a single INE component cannot adequately reproduce the features for the entire X-ray spectrum because the ionization structure of iron ions responsible for the K emission is inconsistent with that of the ions responsible for the lower-energy lines, and the flux of the highest-energy X-rays is underestimated. The iron K line and the high-energy continuum could arise from the same INE component, but the identification of this component with either the blast wave or the ejecta in the standard model is difficult. In Tycho, the high-energy data rule out a class of models for the lower-energy data which have too large a continuum contribution.

Pravdo, S. H.; Nugent, J. J.

1983-01-01

203

A multiwavelength study of the radio source G296.7-0.9: confirmation as a Galactic supernova remnant  

NASA Astrophysics Data System (ADS)

We present a multiwavelength study of the radio source G296.7-0.9. This source has a bilateral radio morphology, a radio spectral index of -0.5 ± 0.1, sparse patches of linear polarization and thermal X-rays with a bright arc near the radio boundary. Considering these characteristics, we conclude that G296.7-0.9 is a supernova remnant (SNR). The age and morphology of the SNR in the context of its environment suggest that the source is co-located with an H II region, and that portions of the shock front have broken out into a lower density medium. We see no evidence for a neutron star or pulsar wind nebula associated with SNR G296.7-0.9.

Robbins, W. J.; Gaensler, B. M.; Murphy, T.; Reeves, S.; Green, A. J.

2012-01-01

204

Interaction of Supernova Remnants with Stellar-Wind Bubbles  

NASA Astrophysics Data System (ADS)

We have developed a spherical FCT code in order to simulate the interaction of supernova remnants with stellar wind bubbles. We assume that the density profile of the supernova ejecta follows the Chevalier model(1982) where the outer portion has a power-law density distribution(rho~r^{-n}) and the SN ejecta has a kinetic energy of 10^51 ergs. The structure of wind bubble has been calculated with the stellar mass loss rate dM/dt=5x10e-6 Mo/yr and the wind velocity v=2x10e3km/s. We have simulated seven models with different initial conditions. In the first two models we computed the evolution of SNRs with n=7 and n=14 in the uniform medium. The numerical results agree with the Chevalier's similarity solution at early times. When all of the power-law portion of the ejecta is swept up by the reverse shock, the evolution slowly converges to the Sedov-Taylor stages. There is not much difference between the two cases with different n's. The other five models simulate SNRs produced inside wind bubbles. In model III, we consider the SN ejecta of 1.4 Mo and the radius of bubble ~2,76pc so that ratio of the mass alpha(=M_{W,S}/Mej) is 2. We follow the complex hydrodynamic flows produced by the interaction of SN shocks with stellar shocks and with the contact discontinuities. In the model III, the time scale for the SN shock to cross the wind shell taucross is similar to the time scale for the reverse shock to sweep the power-law density profile taubend. Hence the SN shock crosses the wind shell. At late times SN shock produces another shell in the ambient medium so that we have a SNR with double shell structure. From the numerical results of the remaining models, we have found that when taucross/taubend <= 2. or equivalently when alpha<=50, the SNRs produced inside wind bubbles have double shell structure. Otherwise, either the SN shock does not cross the wind shell or even if it crosses at one time, the reverse shock reflected at the center accelerates the wind shell to merge into the SN shock. Our results confirm the conclusion of Tenorio-Tagle et al(1990).

Lee, Jae Kwan; Koo, Bon-Chul

1997-12-01

205

Far-Infrared Luminous Supernova Remnant Kes 17  

NASA Astrophysics Data System (ADS)

We present the results of infrared (IR; 2.5-160 ?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 ~8100 L 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: ~79 K (hot) and ~27 K (cold) corresponding to the dust masses of ~6.2 × 10-4 M sun and ~6.7 M 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 (~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; Koo, Bon-Chul; Onaka, Takashi; Jeong, Woong-Seob; Shinn, Jong-Ho; Sakon, Itsuki

2011-10-01

206

Evolution of Hot Spots in Supernova Remnant 1987A  

NASA Astrophysics Data System (ADS)

Supernova (SN) 1987A in the Large Magellanic Cloud is the first naked-eye SN in over three centuries, and the first SN remnant (SNR) seen to form within a pre-existing circumstellar environment that has been mapped in significant detail. We are now observing a unique period in the formation of SNR 1987A as the high-velocity SN debris overtakes the slowly expanding circumstellar equatorial ring (ER). We present ground-based near-infrared imaging and HST optical imaging of the interaction between the ejecta of SN 1987A and its equatorial circumstellar ring. This interaction has made a transition, from emission restricted to a few ``hot spots'' to a collision producing optical emission over a nearly continuous distribution, with most breaks in P.A. less than 20 degrees. Recent data suggest that the forward blast is now reaching the bulk of the ER material to the east. The centroids of many spots are measured to move at 2000-3000 km s{-1}, which we interpret as a lower limit of the velocity of the forward blast front. Multi-wavelength light curves of the spots show that they do not evolve uniformly, and change significantly on timescales as short as one month. Implications of observed delays between spots appearances suggest that the early appearance of the first hot spot is explained by its inward radial position and a fairly uniform forward blast wave, rather than extraordinary physical circumstances. This research has been supported by grants from NASA (NAG5-3502) and STScI (GO-8806 and GO-8872).

Sugerman, B. E. K.; Lawrence, S. S.; Crotts, A. P. S.; Garnavich, P. M.; Kirshner, R. P.; Challis, P.; Supernova INtensive Studies SINS Collaboration

2002-05-01

207

Interstellar and Ejecta Dust in the Cas A Supernova Remnant  

NASA Astrophysics Data System (ADS)

Infrared continuum observations provide a means of investigating the physical composition of the dust in the ejecta and swept up medium of the Cas A supernova remnant (SNR). Using low-resolution Spitzer IRS spectra (5-35 ?m), and broad-band Herschel PACS imaging (70, 100, and 160 ?m), we identify characteristic dust spectra, associated with ejecta layers that underwent distinct nuclear burning histories. The most luminous spectrum exhibits strong emission features at ~9 and 21 ?m and is closely associated with ejecta knots with strong Ar emission lines. The dust features can be reproduced by magnesium silicate grains with relatively low Mg to Si ratios. Another dust spectrum is associated with ejecta having strong Ne emission lines. It has no indication of any silicate features and is best fit by Al2O3 dust. A third characteristic dust spectrum shows features that are best matched by magnesium silicates with a relatively high Mg to Si ratio. This dust is primarily associated with the X-ray-emitting shocked ejecta, but it is also evident in regions where shocked interstellar or circumstellar material is expected. However, the identification of dust composition is not unique, and each spectrum includes an additional featureless dust component of unknown composition. Colder dust of indeterminate composition is associated with emission from the interior of the SNR, where the reverse shock has not yet swept up and heated the ejecta. Most of the dust mass in Cas A is associated with this unidentified cold component, which is <~ 0.1 M ?. The mass of warmer dust is only ~0.04 M ?.

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

2014-05-01

208

Strong evidence for hadron acceleration in Tycho's supernova remnant  

NASA Astrophysics Data System (ADS)

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

Morlino, G.; Caprioli, D.

2012-02-01

209

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

210

Supernova rate and the number of supernova remnants in M31, M33 and the Galaxy  

NASA Astrophysics Data System (ADS)

The integrated thermal and nonthermal radio luminosities of M31, M33, and the Galaxy are used to estimate the rate of SNe tau(SN) and the number of SNRs in these galaxies. From the present-day mass functions (PDMFs), scaled with the total production rate of Ly-continuum photons, tau(SN) is obtained and compared with other estimates of this quantity. Comparison of the SN rates expected from the PDMFs and from statistics suggest that all stars more massive than about five solar masses become SN II. In that case, tau(SN) = 20 +9 or -5 yr in the Galaxy, 75 +48 or -31 yr in M33, and at least 22 +37 or -13 yr in M31. The minimum energy required to produce the observed nonthermal emission is consistent with a supernova remnant rate tau(SNR) = tau(SN) and a mean minimum energy of remnants of about 5 x 10 to the 50th erg. The total number of SNRs in M31, M33, and the Galaxy is 1000-10,000.

Berkhuijsen, E. M.

1984-11-01

211

ROSAT observations of the supernova remnant 3C 400.2  

NASA Technical Reports Server (NTRS)

We have used the ROSAT point source proportional counter (PSPC) to examine the X-ray emission from 3C 400.2, a supernova remnant (SNR) which is a member of a class of remnants with limb-brightened radio and centrally condensed X-ray morphologies. The X-ray emission fills the radio shell and is characterized by an interior peak in the northwest region of the remnant. Otherwise, the surface brightness has a relatively smooth distribution. The X-ray peak is not correlated with any radio features or with the observed optical filaments. The PSPC X-ray spectrum is not well fitted by a power-law model but can be described in terms of thermal emission from a hot plasma with solar abundances. The only point source along the line of sight to the SNR is associated with a bright foreground F8 star. Thus the X-ray emission from 3C 400.2 is unlikely to be due to synchrotron radiation from an active pulsar. If the emission arises from a thermal plasma and the absorbing column along the line of sight to 3C 400.2 is 7.8 x 10(exp 21)sq cm, then the temperature of the plasma is 0.27 keV, and the 0.4-2.4 keV X-ray luminosity is 1.3 x 10(exp 36) ergs/s for an assumed distance of 6 kpc. An X-ray hardness ratio map shows a slight increase in the hardness of the emission in the regions of the remnant with a higher X-ray surface brightness. Assuming uniform absorption across the remnant, this increase implies the temperature is approximately 1.5 times greater in the high surface brightness regions of SNR. The relatively uniform spectrum and the anticorrelation between X-ray and radio features seems to rule out the possibility that 3C 400.2 is actually two overlapping or interacting SNRs. The morphology of 3C 400.2 can be explained in terms of a multiphase interstellar medium (ISM) in which the primary shock is expanding into an ISM studded with dense cloudlets, if the clouds are evaporated or disrupted on a timescale which is long compared to the age of the SNR. It may also be possible to explain the emission in terms of the interaction of the SNR with a massive wind-driven shell, although the existing models for the evolution of A SNR in this environment suggest that the H-alpha luminosity should be much larger than the X-ray luminosity, which is not observed. We cannot completely rule out the possibility that 3C 400.2's appearance as a centrally peaked X-ray SNR is the result of an interaction between the remnant and a cloud along the line of sight, although this seems unlikely.

Saken, Jon M.; Long, K. S.; Blair, W. P.; Winkler, P. F.

1995-01-01

212

X-ray emission from supernova remnants near gamma-ray sources  

NASA Technical Reports Server (NTRS)

It is noted that the imaging proportional of the Einstein Observatory has been used to search for X-ray emission from eight radio supernova remnants which are near three of the Cos-B unidentified gamma-ray sources: 2CG 311-01, CG 327-0, and CG 333+0. Emissions are observed from three of the remnants and upper limits on the remainder which are consistent with the luminosity expected from a simple blast-wave heated plasma model of the process. Thus none of the remnants are superluminous as might be expected if the pattern of the Crab Nebula were followed. It is thought that the remnant RCW 103 may be Vela-like. It is noted that another of the remnants, Kes 27, has centrally peaked X-ray emission which is unlike the shell-like emission seen for many remnants and which does not correlate well with its asymmetric radio emission.

Lamb, R. C.; Markert, T. H.

1981-01-01

213

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.; Uroševi?, D.; Payne, J. L.; De Horta, A. Y.; Stupar, M.; Gruendl, R.; Dickel, J.

2013-07-01

214

Radio emission from young supernova remnants - Effects of an inhomogeneous circumstellar medium  

NASA Technical Reports Server (NTRS)

The evolution of young supernova remnants has been modeled using a one-dimensional hydrodynamics code. Rayleigh-Taylor instabilities and the growth of Rayleigh-Taylor fingers have been included in the code. Turbulent dynamo amplification of magnetic fields and both turbulent and shock acceleration of relativistic electrons have been included macroscopically. From this, the distribution of synchrotron luminosity in the remnant has been calculated. It is found that the radio morphology of model remnants expanding into a homogeneous medium does not agree with observations. Expansion into a circumstellar medium with many small cloudlets does produce radio shells which agree with observations. It is suggested that supernova remnants reflect the interaction of ejected matter with a cloudy circumstellar medium.

Dickel, John R.; Eilek, Jean A.; Jones, Eric M.; Reynolds, Stephen P.

1989-01-01

215

Observations of Very High Energy Gamma-Ray Emission from Supernova Remnants with VERITAS  

NASA Astrophysics Data System (ADS)

The nature and source of cosmic rays has been at the core of particle astrophysics since their discovery almost a century ago. The cosmic ray spectrum is best described by a broken power law, and can be better understood as three distinct parts. Theory holds that cosmic rays up to ˜­10^15 eV - those below the "knee" or steepening in the spectrum - are produced in the shocks of supernova remnants. Direct detection of cosmic rays produced in supernova remnant shocks is impossible, however, as cosmic rays below ˜­10^18 eV are deflected by the Galactic magnetic field and cannot be traced back to their origins. If high energy hadrons are produced within the immediate environment of a supernova remnant, collisions will occur within the surrounding medium. As a result, pion production and subsequent decay will give rise to very high energy gamma rays (E>100 GeV). Since these gamma rays will not interact with any magnetic field, they can be traced back to their point of origin. Thus, Atmospheric Cherenkov Detectors like VERITAS, which have the capability to detect very high energy gamma rays via their interaction with our atmosphere, provide us the means of directly testing the theory of the origin of cosmic rays in supernova remnants. Observations of 13 supernovae made with the VERITAS instrument are presented herein, including 5 individually targeted remnants and 8 remnants within the VERITAS Cygnus region Sky Survey. The observations provide detections of two known VHE remnants (Cassiopeia A and the Crab Nebula), and meaningful flux limits on the remainder. Comparison of these results to both hadronic- and leptonic-origin emission models is carried out.

Theiling, Mark

216

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

217

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

218

The Shock Structure of Supernova Remnant IC443  

NASA Technical Reports Server (NTRS)

We present and discuss ISO observations of IC443, a supernova remnant interacting with a molecular cloud. An SWS spectrum centered on molecular hydrogen clump R10E (RA(2000) = 6 17 7.6, Decl(2000) = 22 25 34.6) is dominated by strong [SiII] (34 microns) emission and the pure rotational transitions of molecular hydrogen ranging from 0-0 S(1) to 0-0 S(13). Fits to these H$-2$ lines imply a large column (approx. 7E19 cm$ {-2)$) of warm (T approx. 700 K) gas and an ortho/para ratio for hydrogen near 3. LWS Fabry-Perot spectra of [OI] (63 microns) and [CII] (158 microns) at positions R10E and C (RA(2000) = 6 17 42.8, Decl(2000) = 22 21 38.1) find broad (approx. 75 km/s), blue-shifted (-40 km/s) line profiles; their similarity strongly suggests a common, shock-generated origin for these two lines. The surprisingly large [CII]/[OI] ratio (approx. 0.1 to 0.2) confirms previous observations with the Kuiper Airborne Observatory. These [CII] and [OI] line intensities, the [SiII] intensity (above), and LWS grating measurements of OH (119 microns) and [OI] (145 microns) are all readily fit by a single, fast J-shock model. Although the [OI] (63) emission can alternatively be produced by a slow C-shock, this ensemble of lines can not be produced by such a shock and provides strong evidence for the existence of a J-shock. A 24-arcmin strip map shows that this far-infrared line emission is spatially correlated with the H$-2$ 1-0 S(1) emission, which most likely arises in an associated C-shock. In addition to this spatially correlated shock emission, the strip map identifies extended [CII] and [OI] emission with a significantly larger line ratio (approx. 0.6); this 'background' component is compared with current J-shock, C-shock, photo-dissociation region (PDR), and X-ray dissociation region (XDR) models in an effort to explain its origin.

Haas, Michael R.; Higdon, S. J. U.; Burton, M. G.; Hollenbach, D. J.; Fonda, Mark (Technical Monitor)

2003-01-01

219

Three-Dimensional Kinematics of the Supernova Remnant Puppis A  

NASA Astrophysics Data System (ADS)

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

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

2010-01-01

220

Supernova remnants and diffuse ionized gas in M31  

NASA Technical Reports Server (NTRS)

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

Walterbos, Rene; Braun, Robert

1990-01-01

221

Comment on ``Collisionless shock and supernova remnant simulations on VULCAN'' [Phys. Plasmas 8, 2439 (2001)  

NASA Astrophysics Data System (ADS)

This recent paper reports some real advances in experimental technique, but is misleading or incorrect in several places. First, the design assumes without discussion that the magnetic field will completely penetrate the plasma, but this is not likely. Second, when the magnetic field is present the surfaces of the converging plasmas will be Rayleigh-Taylor unstable. Third, any shocks produced in experiments like those reported may be collisionless but have no relevance to shocks in supernova remnants. Fourth, the experiment is not a meaningful hydrodynamic simulation of a supernova remnant. Finally, the hydrodynamic simulation results reported are also in error, leading to incorrect values for some scaling parameters.

Drake, R. P.

2002-02-01

222

An astrophysics data program investigation of spatial structure of supernova remnants  

NASA Technical Reports Server (NTRS)

The final report on astrophysics data program investigation of spatial structure of supernova remnants for the period 1 Aug. 1989 to 31 Jul. 1991 is presented. The goal of the project was the study of the spatial structure of supernova remnants (SNR's) as observed in the x-ray band. A number of software tools were developed for the analysis: (1) a program to fit various geometric models to high resolution x-ray data, and (2) programs for Fourier Transform analysis of clumping in SNR's. These programs were applied to high resolution imager (HRI) data on the young galactic SNR's Tycho and Kepler with some success.

Hughes, John P.

1993-01-01

223

TeV gamma-ray flux estimates from EGRET supernova remnant sources  

Microsoft Academic Search

The EGRET experiment, onboard the Compton Gamma-Ray Observatory (CGRO) satellite, has provided evidence of possible ??100 MeV gamma-ray emission from ~ 22 supernova remnants through positional correlation alone. In view of the widely-held belief in the occurrence of cosmic-ray acceleration to energies of ~ 1014 eV in these remnants, we have estimated the TeV gamma-ray fluxes likely to result from

R. K. Kaul

2001-01-01

224

Two X-ray supernova remnants - G296.1 - 0.7 and 1E 1149.4 - 6209  

NASA Technical Reports Server (NTRS)

Using the imaging X-ray detectors on the Einstein Observatory, what appear to be two overlapping galactic supernova remnants are discovered, one of which is clearly identified with the previously cataloged radio remnant G296.1-0.7. The other feature has no radio or optical counterpart. It is a nearly complete ring with a diameter of 20-25 arcmin, designated 1E 1149.4-6209. Because of its morphology, because there is evidence for supernova events in the vicinity, and because there seems to be no plausible alternative, 1E 1149.4-6209 is classified as a supernova remnant. This remnant and others like it, which may be found first in X-rays rather than radio or optical waves, may have important implications regarding the evolution of supernova remnants and the rate of supernovae in our Galaxy.

Markert, T. H.; Lamb, R. C.; Hartman, R. C.; Thompson, D. J.; Bignami, G. F.

1981-01-01

225

OBSERVATION OF SUPERNOVA REMNANT IC 443 WITH THE FERMI LARGE AREA TELESCOPE  

SciTech Connect

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. Past observations suggest IC 443 has been interacting with surrounding interstellar matter. Proximity between dense shocked molecular clouds and GeV-TeV gamma-ray emission regions detected by EGRET, MAGIC, and VERITAS suggests an interpretation that cosmic-ray (CR) particles are accelerated by the SNR. With the high gamma-ray statistics and broad energy coverage provided by the LAT, we accurately characterize the gamma-ray emission produced by the CRs accelerated at IC 443. The emission region is extended in the energy band with theta{sub 68} = 0.{sup 0}27 +- 0.{sup 0}01(stat) +- 0.{sup 0}03(sys) for an assumed two-dimensional Gaussian profile and overlaps almost completely with the extended source region of VERITAS. Its centroid is displaced significantly from the known pulsar wind nebula (PWN) which suggests the PWN is not the major contributor in the present energy band. The observed spectrum changes its power-law slope continuously and continues smoothly to the MAGIC and VERITAS data points. The combined gamma-ray spectrum (200 MeV

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W. [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); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Baughman, B. M. [Department of Physics, Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Burnett, T. H., E-mail: kamae@slac.stanford.ed, E-mail: shia520@stanford.ed, E-mail: francesco.giordano@ba.infn.i, E-mail: dtorres@ieec.uab.e, E-mail: arodrig@ieec.uab.e [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States)

2010-03-20

226

The Crab nebula and other historical supernova remnants  

Microsoft Academic Search

Historical records are investigated to obtain information on historical supernovae. Chinese astronomical records provide the most useful data on solar system events. The reliability and completeness of the Chinese records are evaluated; examples of events recorded and substantiated are given. A historical review of the observations of the Crab nebula, the first historical supernova to be identified, is presented. Detected

V. Trimble; D. H. Clark

1985-01-01

227

The x-ray structure of the supernova remnant W49B  

NASA Astrophysics Data System (ADS)

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

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

228

Investigation of Supernova Remnant Shocks in the Vela-Puppis Region  

NASA Technical Reports Server (NTRS)

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

Sankrit, Ravi

2005-01-01

229

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

SciTech Connect

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

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

2013-07-01

230

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

231

X-ray emission from reverse-shocked ejecta in supernova remnants  

NASA Technical Reports Server (NTRS)

A simple physical model of the dynamics of a young supernova remnant is used to derive a straightforward kinematical description of the reverse shock. With suitable approximations, formulae can then be developed to give the X-ray emission of the reverse-shocked ejecta. The results are found to agree favorably with observations of SN1006.

Cioffi, Denis F.; Mckee, Christopher F.

1990-01-01

232

FUSE Spectroscopy of the Large Magellanic Cloud Supernova Remnant N49  

Microsoft Academic Search

Strong C III lambda977 and O VI lambdalambda1032, 1038 emission lines are detected in Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of N49, the brightest optical supernova remnant in the Large Magellanic Cloud. Shocks with velocities ranging from less than 130 to more than 180 km s-1 are responsible for these emission lines and are present over the entire eastern half

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

2004-01-01

233

Supernova Explosions in the Early Universe: Evolution of Radiative Remnants and the Halo Destruction Efficiency  

Microsoft Academic Search

We study the evolution of supernova (SN) remnants of the first stars, taking proper account of the radiative feedback of the progenitor stars on the surroundings. We carry out a series of one-dimensional hydrodynamic simulations with radiative cooling, starting from initial configurations that are drawn from the results of our earlier radiation hydrodynamic simulations of the first H II regions.

Tetsu Kitayama; Naoki Yoshida

2005-01-01

234

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

Microsoft Academic Search

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

Gary L. Case; Dipen Bhattacharya

1998-01-01

235

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

236

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

NASA Technical Reports Server (NTRS)

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

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

1979-01-01

237

Nearby supernova remnants and the cosmic ray spectral hardening at high energies  

NASA Astrophysics Data System (ADS)

Recent measurements of cosmic ray spectra of several individual nuclear species by the CREAM, TRACER and ATIC experiments indicate a change in the spectral index of the power laws at TeV energies. Possible explanations among others include non-linear diffusive shock acceleration of cosmic rays, different cosmic ray propagation properties at higher and lower energies in the Galaxy and the presence of nearby sources. In this paper, we show that if supernova remnants are the main sources of cosmic rays in our Galaxy, the effect of the nearby remnants can be responsible for the observed spectral changes. Using a rigidity-dependent escape of cosmic rays from the supernova remnants, we explain the apparent observed property that the hardening of the helium spectrum occurs at relatively lower energies as compared to the protons and also that the spectral hardening does not persist beyond ˜(20-30) TeV energies.

Thoudam, Satyendra; Hörandel, Jörg R.

2012-04-01

238

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

NASA Technical Reports Server (NTRS)

The faint optical filaments in Tycho's supernova remnant appear to be emission from a shock front moving at 5600 km/s. 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 gas. The presence of the neutral gas can be used to set an upper limit of approximately 5 x 10 to the 47th power ergs to the energy in ionizing radiation emitted by a Type I supernova. The patchy neutral gas is probably part of the warm neutral component of the interstellar medium. The existing information on the remnant of SN 1006 indicates that its emission is similar in nature to that from Tycho's remnant.

Chevalier, R. A.; Raymond, J. C.

1978-01-01

239

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

NASA Technical Reports Server (NTRS)

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

Shull, J. M.

1982-01-01

240

Near-Infrared Study of Iron Knots in Cassiopeia A Supernova Remnant  

NASA Astrophysics Data System (ADS)

We present the results of near-infrared (NIR) imaging and spectroscopic observations of the Galactic supernova remnant Cassiopeia A (Cas A). Applying the method of Principal Component Analysis to our broadband NIR spectra, we identify a total of 61 NIR emission knots of Cas A and classify them into three groups of distinct spectral characteristics: Helium-rich, Sulfur-rich, and Iron-rich groups. The first and second groups are of the circumstellar and supernova ejecta origin, respectively. The third group, which has enhanced iron emission, is of particular interests since it shows intermediate characteristics between the former two groups. We suggest that the Iron-rich group is knots of swept-up circumstellar medium around the contact discontinuity in Cas A and/or supernova ejecta from deep layers of its progenitor star which have recently encountered a reverse shock in the remnant.

Lee, Yong-Hyun; Koo, Bon-Chul; Moon, Dae-Sik; Burton, Michael G.

2014-01-01

241

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

242

Interactions Between CRs and MCs in the Vicinity of Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Hewitt, John W.

2011-01-01

243

An XMM-Newton Search for Crab-like Supernova Remnants  

NASA Technical Reports Server (NTRS)

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

Mushotzky, Richard (Technical Monitor); Slane, Patrick

2005-01-01

244

The Youngest Known X-Ray Binary: Circinus X-1 and Its Natal Supernova Remnant  

NASA Astrophysics Data System (ADS)

Because supernova remnants are short-lived, studies of neutron star X-ray binaries within supernova remnants probe the earliest stages in the life of accreting neutron stars. However, such objects are exceedingly rare: none were known to exist in our Galaxy. We report the discovery of the natal supernova remnant of the accreting neutron star Circinus X-1, which places an upper limit of t < 4600 yr on its age, making it the youngest known X-ray binary and a unique tool to study accretion, neutron star evolution, and core-collapse supernovae. This discovery is based on a deep 2009 Chandra X-ray observation and new radio observations of Circinus X-1. Circinus X-1 produces type I X-ray bursts on the surface of the neutron star, indicating that the magnetic field of the neutron star is small. Thus, the young age implies either that neutron stars can be born with low magnetic fields or that they can rapidly become de-magnetized by accretion. Circinus X-1 is a microquasar, creating relativistic jets that were thought to power the arcminute-scale radio nebula surrounding the source. Instead, this nebula can now be attributed to non-thermal synchrotron emission from the forward shock of the supernova remnant. The young age is consistent with the observed rapid orbital evolution and the highly eccentric orbit of the system and offers the chance to test the physics of post-supernova orbital evolution in X-ray binaries in detail for the first time.

Heinz, S.; Sell, P.; Fender, R. P.; Jonker, P. G.; Brandt, W. N.; Calvelo-Santos, D. E.; Tzioumis, A. K.; Nowak, M. A.; Schulz, N. S.; Wijnands, R.; van der Klis, M.

2013-12-01

245

The Vela Pulsar and Its Synchrotron Nebula  

Microsoft Academic Search

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

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

2000-01-01

246

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

SciTech Connect

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

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

2013-08-10

247

Evolution of Post-impact Remnant Helium Stars in Type Ia Supernova Remnants within the Single-degenerate Scenario  

NASA Astrophysics Data System (ADS)

The progenitor systems of Type Ia supernovae (SNe Ia) are still under debate. Based on recent hydrodynamics simulations, non-degenerate companions in the single-degenerate scenario (SDS) should survive the supernova (SN) impact. One way to distinguish between the SDS and the double-degenerate scenario is to search for the post-impact remnant stars (PIRSs) in SN Ia remnants. Using a technique that combines multi-dimensional hydrodynamics simulations with one-dimensional stellar evolution simulations, we have examined the post-impact evolution of helium-rich binary companions in the SDS. It is found that these helium-rich PIRSs (He PIRSs) dramatically expand and evolve to a luminous phase (L ~ 104 L ?) about 10 yr after an SN explosion. Subsequently, they contract and evolve to become hot blue-subdwarf-like (sdO-like) stars by releasing gravitational energy, persisting as sdO-like stars for several million years before evolving to the helium red-giant phase. We therefore predict that a luminous OB-like star should be detectable within ~30 yr after the SN explosion. Thereafter, it will shrink and become an sdO-like star in the central regions of SN Ia remnants within star-forming regions for SN Ia progenitors evolved via the helium-star channel in the SDS. These He PIRSs are predicted to be rapidly rotating (v rot >~ 50 km s-1) and to have high spatial velocities (v linear >~ 500 km s-1). Furthermore, if SN remnants have diffused away and are not recognizable at a later stage, He PIRSs could be an additional source of single sdO stars and/or hypervelocity stars.

Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E.

2013-08-01

248

Radio-continuum study of Large Magellanic Cloud supernova remnant J0509-6731  

NASA Astrophysics Data System (ADS)

We present a detailed study of Australia Telescope Compact Array observations (? = 20, 13, 6 and 3 cm) of supernova remnant (SNR) J0509-6731 in the Large Magellanic Cloud. The remnant has a ring morphology with brightened regions towards the south-western limb. We also find a second brightened inner ring which is only seen in the radio continuum. The SNR is almost circular, with a diameter ranging from 7 to 8 pc, and a steep radio spectral index between 36 and 3 cm of ? = -0.73 ± 0.02, which is characteristic of younger SNRs. We also report detection of radially orientated polarization across the remnant at 6 cm, with a mean fractional polarization level of P ? (26 ± 13) per cent. We find the magnetic field (˜168 ?G) and ?-D (? = 1.1 × 10-19 W m-2 Hz-1 sr-1, D = 7.35 pc) to be consistent with other young remnants.

Bozzetto, L. M.; Filipovi?, M. D.; Uroševi?, D.; Kothes, R.; Crawford, E. J.

2014-06-01

249

Supernova Remnant in a Stratified Medium: Explicit, Analytical Approximations for Adiabatic Expansion and Radiative Cooling  

NASA Astrophysics Data System (ADS)

We propose simple, explicit, analytical approximations for the kinematics of an adiabatic blast wave propagating in an exponentially stratified ambient medium and for the onset of radiative cooling, which ends the adiabatic era. Our method, based on the Kompaneets implicit solution and the Kahn approximation for the radiative cooling coefficient, gives straightforward estimates for the size, expansion velocity, and progression of cooling times over the surface when applied to supernova remnants (SNRs). The remnant shape is remarkably close to spherical for moderate density gradients, but even a small gradient in ambient density causes the cooling time to vary substantially over the remnant's surface, so that for a considerable period there will be a cold dense expanding shell covering only a part of the remnant. Our approximation provides an effective tool for identifying the approximate parameters when planning two-dimensional numerical models of SNRs, the example of W44 being given in a subsequent paper.

Maciejewski, Witold; Cox, Donald P.

1999-02-01

250

Two-temperature models of old supernova remnants with ion and electron thermal conduction  

NASA Technical Reports Server (NTRS)

To investigate the potential effects thermal conduction may have on the evolution of old supernova remnants, we present the results of 1D (spherically symmetric) numerical simulations of a remnant in a homogeneous interstellar medium for four different cases: (1) without thermal conduction; (2) with both electron and ion thermal conduction assuming equal temperatures; (3) with electron thermal conduction only, following electron and ion temperatures separately; and (4) with both electron and ion thermal conduction following separate temperatures. We followed the entire evolution until the completion of the remnant bubble collapse. Our most significant result is that in remnant evolution studies concerned principally with either the shell or bubble evolution at late times, reasonable results are obtained with single-temperature models. When the electron and ion temperatures are followed separately, however, ion thermal conduction cannot safely be ignored.

Cui, Wei; Cox, Donald P.

1992-01-01

251

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

252

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

253

IRS Mapping of Three LMC Supernova Remnants and Their Surroundings  

Microsoft Academic Search

Supernova SNRs (SNRs) play a significant role in dust production in the interstellar medium (ISM). Dust, in turn, is an important factor in cooling the hot plasma in SNRs. To investigate dust properties in SNRs, we used IRAC and MIPS images of 6 SNRs in the Large Magellanic Cloud (LMC), and found them to be line-dominated, with little evidence for

Rosa Williams; You-Hua Chu; Gary Ferland; Robert Gruendl

2006-01-01

254

Imagine the Universe: Radioactive Decay in Supernova Remnants  

NSDL National Science Digital Library

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

255

Radio emission from supernova remnants in a cloudy interstellar medium  

NASA Astrophysics Data System (ADS)

The van der Laan (1962) theory of SNR radio emission is modified in light of the inhomogeneity of the interstellar medium, and in order to allow for particle acceleration in shock fronts. It is proposed that most of the radio emission in 10-20 pc radius SNRs originates in cold interstellar clouds that have been crushed by the high pressure hot gas within the expanding remnant. Under these circumstances, simple reacceleration of ambient interstellar cosmic ray electrons can account for the surface brightness-diameter distribution of observed remnants, with the additional, relativistic particle energy compensating for the decreased filling factor of the radio-emitting regions. Warm interstellar gas, at about 8000 K, may also be compressed within very large SNRs (of radius of 30-100 pc) and account for both the giant radio loops, when these SNRs are seen individually, and the anomalously bright galactic nonthermal radio background, which may be the superposition of a number of such features.

Blandford, R. D.; Cowie, L. L.

1982-09-01

256

Radio emission from supernova remnants in a cloudy interstellar medium  

NASA Technical Reports Server (NTRS)

The van der Laan (1962) theory of SNR radio emission is modified in light of the inhomogeneity of the interstellar medium, and in order to allow for particle acceleration in shock fronts. It is proposed that most of the radio emission in 10-20 pc radius SNRs originates in cold interstellar clouds that have been crushed by the high pressure hot gas within the expanding remnant. Under these circumstances, simple reacceleration of ambient interstellar cosmic ray electrons can account for the surface brightness-diameter distribution of observed remnants, with the additional, relativistic particle energy compensating for the decreased filling factor of the radio-emitting regions. Warm interstellar gas, at about 8000 K, may also be compressed within very large SNRs (of radius of 30-100 pc) and account for both the giant radio loops, when these SNRs are seen individually, and the anomalously bright galactic nonthermal radio background, which may be the superposition of a number of such features.

Blandford, R. D.; Cowie, L. L.

1982-01-01

257

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

NASA Technical Reports Server (NTRS)

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

Dwek, Eliahu

2009-01-01

258

Interaction of Rayleigh-Taylor Fingers and Circumstellar Cloudlets in Young Supernova Remnants  

NASA Astrophysics Data System (ADS)

We discover a new dynamical mechanism that significantly enhances the growth of Rayleigh-Taylor fingers developed near the contact interface between the supernova ejecta and swept-up ambient gas in young supernova remnants if the supernova remnant expands into a clumpy (cloudy) circumstellar medium. Our numerical simulation demonstrates that large Rayleigh-Taylor fingers can obtain a sufficient terminal velocity to protrude through the forward shock front by taking extra kinetic energy from vorticies generated by shock-cloud interactions. We suggest this mechanism as a means to generate the aspherical expansion of the supernova ejecta. Ambient magnetic fields are stretched and amplified as the Rayleigh-Taylor fingers protrude, possibly leading to strongly enhanced radio emission. The material in the protrusions originates from the ejected stellar material with greatly enhanced heavy elements. Therefore, it can be a strong X-ray emitter. The timescale for the Rayleigh-Taylor fingers to reach the forward shock depends on the size, mass density, and distribution of clouds being engulfed by the supernova shock, although the details will require further numerical investigation.

Jun, Byung-Il; Jones, T. W.; Norman, Michael L.

1996-09-01

259

On the origin of cosmic rays. [gamma rays and supernova remnants  

NASA Technical Reports Server (NTRS)

Using Recent surveys of molecular clouds and gamma rays in the galaxy, it is possible to determine the distribution of 1 to 10 GeV cosmic-ray nucleons in the galaxy. This distribution appears to be identical to the supernova remnant distribution to within experimental error and provides strong support for the hypothesis that supernovae produce most of the observed cosmic rays. This distribution resembles that of OB associations of average age approximately 30 million years suggesting that cosmic rays are produced by population objects about 30 million years after their birth.

Stecker, F. W.

1975-01-01

260

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

Microsoft Academic Search

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

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

1998-01-01

261

Pulsar winds and other burning questions of astrophysics  

Microsoft Academic Search

This thesis concerns physical processes that are powered or strongly affected by the rapid rotation of neutron stars. In the first part, we study the interaction of relativistic outflows from rotation-powered pulsars with surrounding supernova remnants. We describe results from time-dependent numerical modeling of the collisionless reverse shock terminating the pulsar wind in the Crab Nebula. We treat the upstream

Anatoly Spitkovsky

2002-01-01

262

Evidence for shock acceleration of high-energy electrons in the supernova remnant SN1006  

NASA Astrophysics Data System (ADS)

HIGH-ENERGY cosmic rays (relativistic heavy nuclei) play an important role in heating interstellar matter in the Milky Way1,2, and they affect chemical abundances through collisions with atoms in the interstellar gas2. Although it has long been thought that these cosmic rays arise from supernovae3,4, direct evidence for such an association has been lacking. Here we report X-ray observations of the remnant of supernova 1006, made by the ASCA satellite, which indicate that emission from the edges of the remnant shell is dominated by radiation from electrons accelerated to energies of ˜ 100 TeV within the shock front. Ions in the shell are likely to have been accelerated to similar energies, thus giving rise to very-high-energy cosmic rays.

Koyama, K.; Petre, R.; Gotthelf, E. V.; Hwang, U.; Matsuura, M.; Ozaki, M.; Holt, S. S.

1995-11-01

263

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

264

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

SciTech Connect

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

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

2013-02-10

265

On gamma-ray sources, supernova remnants, OB associations, and the origin of cosmic rays  

Microsoft Academic Search

Spatial coincidences between supernova remnants and OB associations or H II regions are sought, and a list of about 30 objects (referred to as 'SNOBs') is obtained. On the basis of COS B data it is found that five, or perhaps six, of 11 as-yet unidentified gamma-ray sources are associated with SNOBs and that as many as three-fourths of the

T. Montmerle

1979-01-01

266

New shell radio supernova remnant G16.2-2.7  

Microsoft Academic Search

The extended radio source G16.2-2.7 is detected as a new previously uncataloged Galactic supernova remnant. Its non-thermal radio spectrum has spectral index alpha =-0.51, with S_nu (1 GHz) = 2.08 Jy, as being measured with the RATAN-600 radio telescope. The NRAO VLA Sky Survey (NVSS) map at 1.4 GHz shows a shell-like bilateral structure. The similar smoothed image from the

S. A. Trushkin

1999-01-01

267

Spitzer Space Telescope Observations of Kepler's Supernova Remnant: A Detailed Look at the Circumstellar Dust Component  

Microsoft Academic Search

We present 3.6 - 160 micron infrared images of Kepler's supernova remnant\\u000a(SN1604) obtained with the IRAC and MIPS instruments on the Spitzer Space\\u000aTelescope. We also present MIPS SED low resolution spectra in the 55 - 95\\u000amicron region. The observed emission in the MIPS 24 micron band shows the\\u000aentire shell. Emission in the MIPS 70 micron and

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

2007-01-01

268

Spitzer Space Telescope Observations of Kepler's Supernova Remnant: A Detailed Look at the Circumstellar Dust Component  

Microsoft Academic Search

We present 3.6-160 mum infrared images of Kepler's supernova remnant (SN 1604) obtained with the IRAC and MIPS instruments on the Spitzer Space Telescope. We also present MIPS SED low-resolution spectra in the 55-95 mum region. The observed emission in the MIPS 24 mum band shows the entire shell. Emission in the MIPS 70 mum and IRAC 8 mum bands

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

2007-01-01

269

Spitzer Observations of Supernova Remnants. II. Physical Conditions and Comparison with HH7 and HH54  

Microsoft Academic Search

We have studied the shock-excited molecular regions associated with four supernova remnants (SNRs)---IC443C, W28, W44, and 3C391---and two Herbig-Haro objects---HH7 and HH54---using Spitzer's Infrared Spectrograph (IRS). The physical conditions within the observed areas (roughly ~1' × 1' in size) are inferred from spectroscopic data obtained from IRS and from the Short and Long Wavelength Spectrometers on board the Infrared Space

Yuan Yuan; David A. Neufeld

2011-01-01

270

G54.1 + 0.3 - A new Crab-like supernova remnant  

NASA Technical Reports Server (NTRS)

High-resolution multifrequency observations with the VLA and OSRT of the small-diameter flat-spectrum radio source G54.1 + 0.3 are presented. The filled-center brightness distribution, strong polarization at 6 cm, and flat radio spectrum (alpha of about -0.13) from 0.327 to 5 GHz confirm that G54.1 + 0.3 is a Crab-like supernova remnant.

Velusamy, T.; Becker, R. H.

1988-01-01

271

Thermal X-Ray Emission and Cosmic-Ray Production in Young Supernova Remnants  

Microsoft Academic Search

We have developed a simple model to investigate the modifications of the hydrodynamics and nonequilibrium ionization X-ray emission in young supernova remnants due to nonlinear particle acceleration. In nonlinear, diffusive shock acceleration, the heating of the gas to X-ray-emitting temperatures is strongly coupled to the acceleration of cosmic-ray ions. If the acceleration is efficient and a significant fraction of the

Anne Decourchelle; Donald C. Ellison; Jean Ballet

2000-01-01

272

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

Microsoft Academic Search

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

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

2004-01-01

273

Modeling of Non Equilibrium Ionizing Plasmas: Applications and Comparison with Supernova Remnant Observations by the RGS spectrometer  

Microsoft Academic Search

Shocked plasmas of young supernova remnants (SNRs) are in a transient (but very long) phase of being ionized. In these remnants, the temperature is high compared with the charge states present in the plasma. Consequently, the standard single-ion collisional plasma models are inadequate for analyzing SNR spectra. We have developed a non equilibrium ionization model that includes two or more

E. Behar; A. Rasmussen; J. Cottam; S. M. Kahn; F. B. S. Paerels; J. R. Peterson; M. Sako; A. C. Brinkman; A. J. F. den Boggende; J. W. den Herder; C. P. de Vries; C. Ferrigno; J. S. Kaastra; R. Mewe; T. Tamura; K. J. van der Heyden; G. Branduardi-Raymont; I. Sakelliou; M. Audard; M. Gudel; C. Erd

2000-01-01

274

The 7Li/6Li Isotope Ratio near the Supernova Remnant IC 443  

NASA Astrophysics Data System (ADS)

We present an analysis of 7Li/6Li isotope ratios along four sight lines that probe diffuse molecular gas near the supernova remnant IC 443. Recent gamma-ray observations have revealed the presence of shock-accelerated cosmic rays interacting with the molecular cloud surrounding the remnant. Our results indicate that the 7Li/6Li ratio is lower in regions more strongly affected by these interactions, a sign of recent Li production by cosmic rays. We find that 7Li/6Li ?7 toward HD 254755, which is located just outside the visible edge of IC 443, while 7Li/6Li ?3 along the line of sight to HD 43582, which probes the interior region of the supernova remnant. No evidence of 7Li synthesis by neutrino-induced spallation is found in material presumably contaminated by the ejecta of a core-collapse supernova. The lack of a neutrino signature in the 7Li/6Li ratios near IC 443 is consistent with recent models of Galactic chemical evolution, which suggest that the ?-process plays only a minor role in Li production. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Taylor, C. J.; Ritchey, A. M.; Federman, S. R.; Lambert, D. L.

2012-05-01

275

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

SciTech Connect

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

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

2012-05-01

276

The evolution of supernova remnants in a non-uniform medium The fate of an evolving OB association  

Microsoft Academic Search

The effect of multiple supernova explosions in a nonuniform interstellar medium is studied using a two dimensional hydrodynamical code (axial symmetry assumed). Cooling effects were included. In a uniform medium two or more supernovae exploding at the same place but at different times result in a remnant with less energy than the sum of the individual explosion energies - when

P. Bodenheimer; H. W. Yorke; G. Tenorio-Tagle; M. Beltrametti

1983-01-01

277

A distance determination for the supernova remnant G27.4+0.0 and its central X-ray source  

NASA Technical Reports Server (NTRS)

We have determined the distance to the supernova remnant G27.4+0.0, one of the handful of remnants with a bright central X-ray source. H I absorption data obtained with the VLA toward the remnant and adjacent H II regions allow us to constrain the distance to G27.4+0.0 to lie between 6 and 7.5 kpc. We briefly discuss the implications of this result for the nature of the central source.

Sanbonmatsu, K. Y.; Helfand, D. J.

1992-01-01

278

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

SciTech Connect

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

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

2013-04-01

279

Remnant Stars in Supernova Remnants-Cont of 4083 Part 2  

NASA Astrophysics Data System (ADS)

In this proposal we will search for a remnant star associated with SN1987A. Once detected, we will study the photometric variability in an attempt to place important constraints on the mechanisms by which neutron stars originate. REVISION HISTORY: Created 11/18/91; Added image--BJW 1/18/93; Split by STScI implemented--BJW 1/27/92;

Bless, Robert

1992-07-01

280

FERMI-LAT STUDY OF GAMMA-RAY EMISSION IN THE DIRECTION OF SUPERNOVA REMNANT W49B  

SciTech Connect

We present an analysis of the gamma-ray data obtained with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope in the direction of SNR W49B (G43.3-0.2). A bright unresolved gamma-ray source detected at a significance of 38{sigma} is found to coincide with SNR W49B. The energy spectrum in the 0.2-200 GeV range gradually steepens toward high energies. The luminosity is estimated to be 1.5 x 10{sup 36} (D/8 kpc){sup 2} erg s{sup -1} in this energy range. There is no indication that the gamma-ray emission comes from a pulsar. Assuming that the supernova remnant (SNR) shell is the site of gamma-ray production, the observed spectrum can be explained either by the decay of neutral {pi} mesons produced through the proton-proton collisions or by electron bremsstrahlung. The calculated energy density of relativistic particles responsible for the LAT flux is estimated to be remarkably large, U{sub e,p}>10{sup 4} eV cm{sup -3}, for either gamma-ray production mechanism.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Bechtol, K.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Buehler, R. [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); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P. [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); Caliandro, G. A., E-mail: uchiyama@slac.stanford.ed, E-mail: htajima@slac.stanford.ed, E-mail: Taka.Tanaka@stanford.ed, E-mail: katsuta@astro.isas.jaxa.j [Institut de Ciencies de l'Espai (IEEC-CSIC), Campus UAB, 08193 Barcelona (Spain)

2010-10-20

281

Spallative production of Li, Be and B in supernova remnants  

NASA Astrophysics Data System (ADS)

We calculate the light element production induced by the explosion of an isolated supernova in the ISM. We use a time-dependent model and consider energetic particles accelerated at the forward (process 1) and reverse (process 2) shocks. Both processes are primary, but are shown to underproduce Be and B in the early Galaxy. The reasons for this failure are analyzed and used to determine what basic characteristics a model should involve in order to be successful. Quite remarkably, we find that these requirements seem to converge toward a model involving superbubbles as the site of particle acceleration out of a metal-rich material. Such a model is presented in the accompanying paper OG.3.2.51.

Parizot, Etienne

1999-08-01

282

Unpulsed X-rays from pulsars  

NASA Technical Reports Server (NTRS)

Preliminary results of several programs to detect thermal X-ray emission from isolated neutron stars are presented. Results of Einstein pulsar surveys indicate that either the majority of supernovas which leave remnants do not produce neutron stars, or the cooling calculations are in need of substantial revision. When appropriate relativistic thermodynamics and updated high energy nuclear physics are included, the new calculations predict significantly lower temperatures for standard neutron star equations of state. X-ray results give strong evidence that five of the seven historical remnants and a large majority of the other remnants of less than 1000 yr do not contain radio pulsars. A survey of known radio pulsars is also presented, which is designed to test the heating mechanisms required by various theories of pulsar emission and neutron star structure, and consists of a survey of all known pulsars within 300 pc.

Helfand, D. J.

1981-01-01

283

Shock and Awe: Measuring the Expansion of the Shock Front of Supernova Remnant SN1006  

NASA Astrophysics Data System (ADS)

We have determined the expansion of the supernova remnant (SNR) of SN1006 over a seven-year period, using data collected in 2003 and 2010. The data was calibrated and imaged using Miriad and CASA programming before we stacked the two images to accurately assess the expansion rate. Our data was collected from the Very Large Array (VLA) in New Mexico and Australian Telescope Compact Array (ATCA). The 2003 epoch observations were conducted at the ATCA and the VLA. The 2010 epoch observations were conducted only at the ATCA. We processed the data using the Miriad and CASA software packages, which allowed us to perform calibration and imaging of radio interferometer visibility data. We deconvolved the raw images using CLEAN and MAXEN (maximum entropy deconvolution) to remove spurious side lobes, resulting in epoch images with a synthesized beamwidth of 6.0 arcseconds per beam. We used the 2010 image as a template to align the 2003 image and to match resolution. A difference image formed from the two epoch images reveals an obvious expansion of the SNR. We measured the expansion rate at nine points along the shell of the remnant. We found that the expansion rate varied across the remnant’s shell. The greatest amount of expansion measured was 5.71 arcseconds over seven years, which for a distance of 2.2 kpc, has the remnant moving at 8,500 km/s. The average expansion measured across the shell was 4.25 arcseconds over seven years.

Dills, Sidney; McKinney, L.; Moffett, D. A.; Reynoso, E.

2014-01-01

284

Supernova Remnants in the Magellanic Clouds. IX. Multiwavelength Analysis of the Physical Structure of N49  

NASA Astrophysics Data System (ADS)

We present a multiwavelength analysis of the supernova remnant N49 in the Large Magellanic Cloud. Using high-resolution Hubble Space Telescope WFPC2 images of H?, [S II], and [O III] emission, we study the morphology of the remnant and calculate the rms electron densities in different regions. We detect an offset of [O III] and H? emission peaks of about 0.5? and discuss possible scenarios that could give rise to such high values. The kinematics of the remnant is analyzed by matching individual kinematic features in the echelle spectra obtained at the Cerro Tololo Inter-American Observatory with the morphological features revealed in the WFPC2 images. We detect a narrow H? emission component and identify it as diffuse preshock recombination radiation, and discrete broad emission features that correspond to the shocked gas in filaments. The overall expansion of the remnant is about 250 km s-1. The dense clouds are shocked up to line-of-sight velocities of 250 km s-1, and the less dense gas up to 300 km s-1. A few cloudlets have even higher radial velocities, reaching up to 350 km s-1. We confirm the presence of the cavity in the remnant and identify the center of explosion. Using archival Chandra and XMM-Newton data, we observe the same trends in surface brightness distribution for the optical and X-ray images. We carry out a spectral analysis of three regions that represent the most significant optical features.

Bilikova, J.; Williams, R. N. M.; Chu, Y.-H.; Gruendl, R. A.; Lundgren, B. F.

2007-12-01

285

THE ABSENCE OF EX-COMPANIONS IN TYPE Ia SUPERNOVA REMNANTS  

SciTech Connect

Type Ia supernovae (SNe Ia) play important roles in our study of the expansion and acceleration of the universe, but because we do not know the exact nature or natures of the progenitors, there is a systematic uncertainty that must be resolved if SNe Ia are to become more precise cosmic probes. No progenitor system has ever been identified either in the pre- or post-explosion images of a Ia event. There have been recent claims for and against the detection of ex-companion stars in several SNe Ia remnants. These studies, however, usually ignore the angular momentum gain of the progenitor white dwarf (WD), which leads to a spin-up phase and a subsequent spin-down phase before explosion. For spin-down timescales greater than 10{sup 5} years, the donor star could be too dim to detect by the time of explosion. Here we revisit the current limits on ex-companion stars to SNR 0509-67.5, a 400-year-old remnant in the Large Magellanic Cloud. If the effects of possible angular momentum gain on the WD are included, a wide range of single-degenerate progenitor models are allowed for this remnant. We demonstrate that the current absence of evidence for ex-companion stars in this remnant, as well as other SNe Ia remnants, does not necessarily provide the evidence of absence for ex-companions. We discuss potential ways to identify such ex-companion stars through deep imaging observations.

Di Stefano, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kilic, Mukremin, E-mail: rd@cfa.harvard.edu, E-mail: kilic@ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States)

2012-11-01

286

Multi-wavelength analysis of supernova remnant MSH11-61A  

NASA Astrophysics Data System (ADS)

Due to its centrally bright X-ray morphology and limb brightened radio profile, supernova remnant (SNR) MSH11-61A (G290.1-0.8) is classified as mixed morphology. The evolutionary sequence which leads to this centrally bright X-ray morphology is not well understood and currently different models can only explain some of the features seen in individual cases. In this analysis we present a study of MSH11-61A using archival Suzaku data. Our preliminary results indicate enhanced abundances, as previously suggested by ASCA observations and we derive the associated age, energy and ambient density of the remnant using models that we constructed in an attempt to reproduce the observed X-ray properties. Additionally, MSH11-61A is thought to be interacting with a molecular cloud towards the west/south west of the remnant. As observations of thermal and non-thermal emission of SNRs have provided increasing support in favour of cosmic rays being accelerated at the shock front of the remnant, SNRs known to be interacting with molecular clouds provide an effective target for detecting and studying gamma-rays. Using 64 months of Fermi-LAT gamma-ray data, we perform a spatial and spectral analysis of the gamma-ray emission in the region of this remnant, allowing us to constrain the origin of the detected emission.

Auchettl, Katie; Slane, Patrick O.; Castro, Daniel

2014-06-01

287

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

288

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.; Martí-Vidal, I.

2013-12-01

289

Supernova Remnant W44: A Case Study For Thermal Conduction Versus Cloud Evaporation  

NASA Astrophysics Data System (ADS)

The supernova remnant W44 and a handful of similar objects form a small, eccentric class with shell type radio emission and centrally peaked x-ray emission. W44 cannot be explained adequately with Sedov models, but has been modelled assuming that evaporating clouds in the center of the remnant increase the density and thus the x-ray emission. In this project, we consider a simpler scenario: that thermal conduction transports energy outwards from the very hot center. The central pressure matches that in the conduction-free Sedov model, while the central temperature is lower and the density higher. The appreciable central density provides a much higher x-ray emission. In addition, the large column density of intervening H I preferentially absorbs the lower frequency x-ray emission originating in the cooler, outer regions, eliminating the bright shell emission. We use a hydrodynamical simulation, from which we predict the 21 cm, radio synchtrotron (due to the van der Laan mechanism) and x-ray emisssion. Our preliminary results show good agreement with the observations. Thermal conduction appears to provide an alternative to cloud evaporation as a mechanism for supplying thermal x-ray emission in the central regions of supernova remnants.

Shelton, R. L.; Smith, R. K.; Cox, D. P.

1995-05-01

290

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

NASA Technical Reports Server (NTRS)

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

Petre, Robert; Winkler, P. F.

2006-01-01

291

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

292

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

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

293

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

294

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

295

Electron Heating, Magnetic Field Amplification, and Cosmic Ray Precursor Length at Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which provides magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and may be quenched either by nonresonant or resonant channels. In the former case, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to 10^17 - 10^18 cm and is potentially resolvable in Galactic supernova remnants. If the saturation occurs instead by resonant channels, the cosmic rays are scattered by turbulence and the precursor length will likely be too small to be resolvable with current instruments. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly generated shock precursor, which when expressed in terms of the cosmic ray diffusion coefficient ? and shock velocity v_s is ? /v_s. In the nonresonantly saturated case, the precursor length declines less quickly with increasing v_s. Where precursor length proportional to 1/v_s gives constant electron heating, as observed for instance by Ghavamian et al. and van Adelsberg et al., this increased precursor length would be expected to lead to higher electron temperatures at faster supernova remnant shocks than studied by these previous works as an indirect observation of the shock precursor. Existing results and new data analysis of SN 1006 and Cas A suggests some observational support for this idea. Work supported by NASA ADAP program and by basic research funds of the Office of Naval Research.

Laming, J. M.; Hwang, U.; Ghavamian, P.; Rakowski, C. E.

2014-01-01

296

Supernova Remnants and Nucleosynthesis (fos 30): CYCLE4-AUG-CARRYOVER  

NASA Astrophysics Data System (ADS)

Overall program: UV and optical spectra of four supernova remnants (SNRs) will be used to study a number of problems related to abundances, grain destruction, interstellar medium properties and physical conditions in SNR shocks. Representatives of three of the main classes of SNRs (Crab-nebula like, Balmer-line and "normal") will be studied in the LMC, where reasonably low reddening permits UV observations. In earlier parts of the program, an oxygen-rich SNR in NGC 4449 was observed, taking advantage of the small FOS slits to isolate the SNR from surrounding H II emission. Two M33 SNRs that were previously part of this proposal have been dropped due to time limitations. This program: FOS UV/optical spectra of two LMC remnants are to be obtained, following up on EARLY ACQ images from cycle 2. This program has been carried over from before the servicing mission in December 1993.

Davidsen, Arthur

1994-07-01

297

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

298

Interaction of supernova remnants: From the circumstellar medium to the terrestrial laboratory  

SciTech Connect

The evolution of supernova remnants (SNRs) represents a useful and natural laboratory for gasdynamics studies. In this paper the results of several hydrodynamical simulations of the propagation and early phases of interaction of two SNRs embedded in a homogeneous interstellar environment are shown. In particular, the hydrodynamic evolution and collision of twin SNRs during their self-similar stage has been simulated using a two-dimensional Lagrangian hydrocode. In addition, the results of a detailed simulation that attempts to set the adequate conditions to reproduce the same phenomenon through laser ablation of two plastic plugs at the laboratory scale are presented. These results indicate that both large-scale and small-scale simulations display several common features that can be used to design an experiment aimed to validate the hydrodynamical codes. Of particular interest are the structures found around the juncture of the two colliding shells produced by the interaction of the remnants.

Velarde, P.; Garcia-Senz, D.; Bravo, E.; Ogando, F.; Relano, A.; Garcia, C.; Oliva, E. [Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid (Spain); Departament de Fisica i Enginyeria Nuclear, Institut d'Estudis Espacials de Catalunya (UPC), Barcelona (Spain); Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid (Spain); Departament de Fisica i Enginyeria Nuclear, Institut d'Estudis Espacials de Catalunya (UPC), Barcelona (Spain); Instituto de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid (Spain)

2006-09-15

299

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

300

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

301

HIGH RESOLUTION 36 GHz IMAGING OF THE SUPERNOVA REMNANT OF SN 1987A  

SciTech Connect

The aftermath of supernova (SN) 1987A continues to provide spectacular insights into the interaction between an SN blastwave and its circumstellar environment. We here present 36 GHz observations from the Australia Telescope Compact Array of the radio remnant of SN 1987A. These new images, taken in 2008 April and 2008 October, substantially extend the frequency range of an ongoing monitoring and imaging program conducted between 1.4 and 20 GHz. Our 36.2 GHz images have a diffraction-limited angular resolution of 0.''3-0.''4, which covers the gap between high resolution, low dynamic range VLBI images of the remnant and low resolution, high dynamic range images at frequencies between 1 and 20 GHz. The radio morphology of the remnant at 36 GHz is an elliptical ring with enhanced emission on the eastern and western sides, similar to that seen previously at lower frequencies. Model fits to the data in the Fourier domain show that the emitting region is consistent with a thick inclined torus of mean radius 0.''85, and a 2008 October flux density of 27 +- 6 mJy at 36.2 GHz. The spectral index for the remnant at this epoch, determined between 1.4 GHz and 36.2 GHz, is alpha = -0.83. There is tentative evidence for an unresolved central source with flatter spectral index.

Potter, T. M.; Staveley-Smith, L.; Zanardo, G. [International Centre for Radio Astronomy Research (ICRAR), School of Physics M468, University of Western Australia, Crawley WA 6009 (Australia); Ng, C.-Y.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, Sydney NSW 2006 (Australia); Ball, Lewis; Kesteven, M. J.; Manchester, R. N.; Tzioumis, A. K., E-mail: T.Potter@aip.org.a [Australia Telescope National Facility (ATNF), CSIRO, P.O. Box 76, Epping NSW 1710 (Australia)

2009-11-01

302

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

303

Explosion and Remnant Systematics of Neutrino-driven Supernovae for Spherically Symmetric Models  

NASA Astrophysics Data System (ADS)

We present the results of spherically symmetric explosion simulations for a set of about 100 progenitor stars with solar metallicity, performed with the aim of better understanding the connection between progenitors and the properties of core-collapse supernovae. The explosions are initiated artificially by means of a neutrino heating scheme that depends on parametrized neutrino quantities (luminosities and mean spectral energies). The evolution of the models is followed until shock breakout from the stellar surface. In agreement with conclusions that have been drawn from observations, we find a great variability of supernova properties (such as explosion energy, remnant mass and ejected nickel mass) even in narrow progenitor mass windows. We conclude that these differences could be linked to differences in the progenitors structure.

Ugliano, M.; Janka, H.; Arcones, A.; Marek, A.

2012-07-01

304

Water, Hydroxyl and Carbon Monoxide Emission in Molecular Supernova Remnants with Herschel  

NASA Astrophysics Data System (ADS)

We present Herschel observations of supernova remnants (SNRs) that are interacting with molecular clouds using PACS, SPIRE and HIFI. Dense clouds behind strong supernova shocks are astrochemical laboratories to study formation or dissociation of various molecules to probe the effect of high energy emission, precursors, or dust processing. Herschel spectra revealed rich molecular lines of high-J and low-J carbon monoxide, water, hydroxyl and a few atomic lines of oxygen and nitrogen. We observed three SNRs and there is some variation in detections SNR by SNR. We will compare shock and pre-existing molecular properties to understand formation of molecules and their interplay of different molecules, present CO excitation diagrams, and distinguish the shock conditions using various shock models. The shock physical conditions will be compared with those derived from molecular hydrogen lines. We will discuss the abundances of CO, water and OH and astrochemical processes of molecules behind dense molecular shocks.

Rho, Jeonghee; Hewitt, J. W.

2014-01-01

305

Dust Lifetimes and Grain Destruction Rates by Supernova Remnants in the Magellanic Clouds  

NASA Astrophysics Data System (ADS)

The presence of dust in galaxies has a profound effect on their spectral appearance and on the many processes that determine the physical, chemical, and thermal state of their interstellar medium (ISM). Despite the many different manifestation of interstellar dust in the Milky Way and external galaxies, its nature, origin, and evolution are still poorly understood. The understanding of the dust destruction rates by supernova shocks in particular is extremely important for understanding its origin. The amount of grain destruction determines whether the dust budget can be balanced by dust formation in stellar sources, or whether dust growth in molecular clouds is required. Due to their extensive wavelength coverage and known distance, the Magellanic Clouds offer a unique opportunity for studying dust destruction rates and lifetimes in the ISM. I will present new estimates of dust destruction rates by supernova remnants in the Magellanic Clouds and discuss their implications for dust evolution models.

Temim, Tea; Dwek, E.; Meixner, M.; Boyer, M. L.; Tchernyshyov, K.; Gall, C.

2014-01-01

306

SN 1993J - The X-ray Story of a Supernova Slowly Transitioning to a Remnant  

NASA Astrophysics Data System (ADS)

Supernova 1993J in the nearby galaxy M81 is one of the best observed supernovae (SNe) in X-rays, with better long-term X-ray time-sampling than any other SN. We re-analysed most of the available archival data on SN 1993J, combined with a 79ks Chandra observation obtained by our group in Aug 2010. Together, the data constitute a veritable history of a Type IIb SN from its explosion, through its outward journey into the surrounding medium, and on its way to becoming a remnant. The X-ray emission probes the characteristics of the surrounding medium, and the kinematics of the SN shock wave(s). In this project we explore the evolution of these quantities in SN 1993J, together with the evolution of its X-ray spectrum.

Dwarkadas, Vikram; Bauer, Franz E.

2014-06-01

307

New shell radio supernova remnant G16.2-2.7  

Microsoft Academic Search

The extended radio source G16.2-2.7 is detected as a new previously\\u000auncataloged Galactic supernova remnant. Its non-thermal radio spectrum has\\u000aspectral index alpha=-0.51, with S_nu(1 GHz) = 2.08 Jy, as being measured with\\u000athe RATAN-600 radio telescope. The NRAO VLA Sky Survey (NVSS) map at 1.4 GHz\\u000ashows a shell-like bilateral structure. The similar smoothed image from the\\u000aEffelsberg survey

Sergei A. Trushkin

1999-01-01

308

Emissions from supernova remnants in the presence of small-scale random magnetic fields  

NASA Astrophysics Data System (ADS)

We study non-thermal emissions by relativistic electrons from supernova remnants(SNRs) in the presence of small-scale random and large-scale regular magnetic fields. We extend our pure jitter and inverse Compton emission models (Ogasawara et al. 2006) and construct the emission models with regular magnetic fields. We apply them to the multi-wavelength data of TeV gamma-ray sources SNRs RX J1713.7-3946 (G347.3-0.5) and RX J0852.0-4622 (G266.6-1.2). The physical fit parameters of random and regular magnetic fields are discussed.

Yoshida, T.; Yanagita, S.; Kifune, T.

309

Spatial distribution of spectral characteristics of the supernova remnant Cas A  

NASA Astrophysics Data System (ADS)

We present preliminary results about the spatially resolved spectroscopy of the supernova remnant Cas A in the energy band 3-10 keV. Data refer to observations performed with the MECS instrument on board BeppoSAX. Images of Cas A have been accumulated in very narrow energy intervals, and then deconvolved with Lucy's method. The spectral analysis of the deconvolved images allowed us to derive the spatial distribution of the relevant spectral parameters of the source with a resolution of about 30 arcsec. .

Mineo, T.; Maccarone, M. C.; Preite-Martinez, A.; Vink, J.; Kaastra, J. S.

2001-12-01

310

On the maximum energy and escape of accelerated particles in young supernova remnants  

NASA Astrophysics Data System (ADS)

Using analytic expressions and self-similar solutions, we explore different environments in which supernova remnants (SNRs) evolve, and investigate how the maximum energy to which particles are accelerated, and its time evolution, is a function of the complex environment. We take into account the ambient magnetic field and its amplification by resonant or non-resonant modes. We find that particles reach the maximum energies in the ejecta-dominated stage, much earlier than Sedov stage, particularly in the case of core-collapse SNe expanding in the winds of massive stars.

Dwarkadas, Vikram V.; Telezhinsky, Igor; Pohl, Martin

2012-12-01

311

Soft X-ray emission from the Lupus Loop and Sn 1006 supernova remnants  

NASA Technical Reports Server (NTRS)

X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint extended source of soft X-rays with a temperature about 2.5 million K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2-1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star.

Winkler, P. F., Jr.; Hearn, D. R.; Richardson, J. A.; Behnken, J. M.

1979-01-01

312

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

313

IRAS 15099-5856: Remarkable Mid-infrared Source with Prominent Crystalline Silicate Emission Embedded in the Supernova Remnant MSH15-52  

NASA Astrophysics Data System (ADS)

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

Koo, Bon-Chul; McKee, Christopher F.; Suh, Kyung-Won; Moon, Dae-Sik; Onaka, Takashi; Burton, Michael G.; Hiramatsu, Masaaki; Bessell, Michael S.; Gaensler, B. M.; Kim, Hyun-Jeong; Lee, Jae-Joon; Jeong, Woong-Seob; Lee, Ho-Gyu; Im, Myungshin; Tatematsu, Ken'ichi; Kohno, Kotaro; Kawabe, Ryohei; Ezawa, Hajime; Wilson, Grant; Yun, Min S.; Hughes, David H.

2011-05-01

314

Iron Opacity and the Pulsar of Supernova 1987A  

Microsoft Academic Search

Neutron stars formed in Type II supernovae are likely to be initially\\u000aobscured by late-time fallback. Although much of the late-time fallback is\\u000aquickly accreted via neutrino cooling, some material remains on the neutron\\u000astar, forming an atmosphere which slowly accretes through photon emission. In\\u000athis paper, we derive structure equations of the fallback atmosphere and\\u000apresent results of one-dimensional

C. L. Fryer; S. A. Colgate; P. A. Pinto

1998-01-01

315

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, François; Kaspi, Victoria M.

2013-09-01

316

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

NASA Technical Reports Server (NTRS)

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

Hwang, Una; Markert, Thomas H.

1994-01-01

317

Observations of discrete gamma ray sources with SAS-2. [compact sources centered on Crab nebula and Vela X supernova remnant  

NASA Technical Reports Server (NTRS)

Compact gamma ray sources centered on the Crab nebula and the Vela X supernova remnant are considered. An excess in the galactic radiation was observed in both regions. Data indicate that a large fraction of this flux is pulsed. The excess from the Vela region could reflect either a large-scale galactic feature, such as a superposition of spiral arm segments, or it could be associated with the Vela supernova remnant. Low-energy gamma ray bursts were observed in the SAS-2 anticoincidence shielding.

Thompson, D. J.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Bignami, G. F.

1974-01-01

318

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

Microsoft Academic Search

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

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

2002-01-01

319

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

PubMed

Two types of supernova are thought to produce the overwhelming majority of neutron stars in the Universe. The first type, iron-core-collapse supernovae, occurs when a high-mass star develops a degenerate iron core that exceeds the Chandrasekhar limit. The second type, electron-capture supernovae, is associated with the collapse of a lower-mass oxygen-neon-magnesium core as it loses pressure support owing to the sudden capture of electrons by neon and/or magnesium nuclei. It has hitherto been impossible to identify the two distinct families of neutron stars produced in these formation channels. Here we report that a large, well-known class of neutron-star-hosting X-ray pulsars is actually composed of two distinct subpopulations with different characteristic spin periods, orbital periods and orbital eccentricities. This class, the Be/X-ray binaries, contains neutron stars that accrete material from a more massive companion star. The two subpopulations are most probably associated with the two distinct types of neutron-star-forming supernova, with electron-capture supernovae preferentially producing systems with short spin periods, short orbital periods and low eccentricities. Intriguingly, the split between the two subpopulations is clearest in the distribution of the logarithm of spin period, a result that had not been predicted and which still remains to be explained. PMID:22080948

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

2011-11-17

320

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

321

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

NASA Technical Reports Server (NTRS)

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

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

1989-01-01

322

The Gamma-Ray Spectra of Supernova Remnants Arising from SNe of Various Types  

NASA Astrophysics Data System (ADS)

Supernovae (SNe) are generally classified into Type I and Type II. Most SNe, including all those of Type II and Ib/c, arise from the core-collapse of massive stars. During their lifetime, mass-loss from these stars considerably modifies the medium around the stars. When the stars explode as SNe, the resulting shock wave will expand in this wind-modified medium, and the gamma-ray spectra are due to particle acceleration in this medium. In contrast, Type Ia SNe will expand in a relatively uniform medium, but the dynamics are different from those of core-collapse SNe. In this work we compute the spectra of accelerated particles, and the surface brightness distribution at very high energies, for SNRs of various types. We use high-resolution numerical simulations to study the expansion of the SN shock wave in the complicated medium; consider transport of frozen-in magnetic field by the plasma flow within the remnant; calculate cosmic-ray acceleration by solving the cosmic-ray transport equation in the test particle limit; include contributions from both forward and reverse shocks; and trace escaped particles out to about 50 SNR radii. We find that the complex environment, the reverse shock, and plasma-flow profiles all contribute to shaping the particle spectra. Our results show softer spectra for young supernova remnants that are consistent with recent results from Fermi and ground-based telescope arrays.

Dwarkadas, Vikram; Telezhinsky, I.; Pohl, M.

2013-04-01

323

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

324

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

325

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

326

Electron Heating, Magnetic Field Amplification, and Cosmic-Ray Precursor Length at Supernova Remnant Shocks  

NASA Astrophysics Data System (ADS)

We investigate the observability, by direct and indirect means, of a shock precursor arising from magnetic field amplification by cosmic rays. We estimate the depth of such a precursor under conditions of nonresonant amplification, which can provide magnetic field strengths comparable to those inferred for supernova remnants. Magnetic field generation occurs as the streaming cosmic rays induce a plasma return current, and it may be quenched by either nonresonant or resonant channels. In the case of nonresonant saturation, the cosmic rays become magnetized and amplification saturates at higher magnetic fields. The precursor can extend out to 1017-1018 cm and is potentially detectable. If resonant saturation occurs, the cosmic rays are scattered by turbulence and the precursor length will likely be much smaller. The dependence of precursor length on shock velocity has implications for electron heating. In the case of resonant saturation, this dependence is similar to that in the more familiar resonantly generated shock precursor, which when expressed in terms of the cosmic-ray diffusion coefficient kappav and shock velocity vs is kappav/vs . In the nonresonantly saturated case, the precursor length declines less quickly with increasing vs . Where precursor length proportional to 1/vs gives constant electron heating, this increased precursor length could be expected to lead to higher electron temperatures for nonresonant amplification. This should be expected at faster supernova remnant shocks than studied by previous works. Existing results and new data analysis of SN 1006 and Cas A suggest some observational support for this idea.

Laming, J. Martin; Hwang, Una; Ghavamian, Parviz; Rakowski, Cara

2014-07-01

327

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

328

Supernova Remnants Associated with Molecular Clouds in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We used the Swedish-ESO Submillimeter Telescope (SEST) to search for CO emission associated with three supernova remnants (SNRs) in the Large Magellanic Cloud: N49, N132D, and N23. Observations were carried out in the J = 2 --> 1 rotational transition of CO (230.5 GHz) where the half-power beamwidth of the SEST is 23". Molecular clouds were discovered near N49 and N132D; no CO emission was discovered in the region we mapped near N23. The N49 cloud has a peak line temperature of 0.75 K, spatial scale of ~7 pc and virial mass of ~3 × 104 M?. The N132D cloud is brighter with a peak temperature of 5 K; it is also larger ~22 pc and considerably more massive ~2 × 105 M?. The velocities derived for the clouds near N49 and N132D, +286.0 and +264.0 km s-1, agree well with the previously known velocities of the associated SNRs: +286 km s-1 and +268 km s-1, respectively. ROSAT X-ray images show that the ambient density into which the remnants are expanding appears to be significantly increased in the direction of the clouds. Taken together these observations indicate a physical association between the remnants and their respective, presumably natal, molecular clouds. The association of N49 and N132D with dense regions of molecular material means that both were likely products of short-lived progenitors that exploded as core-collapse supernovae.

Banas, Kenneth R.; Hughes, John P.; Bronfman, L.; Nyman, L.-Å.

1997-05-01

329

Giant-scale supernova remnants - The role of differential galactic rotation and the formation of molecular clouds  

NASA Technical Reports Server (NTRS)

The evolution of remnants produced by the total supernova power from an evolved OB association in a differentially rotating galactic disk is presented. The calculations at 5 kpc and 10 kpc from the galactic center lead to column densities across the remnant shell, or across sections of the remnants, which eventually exceed the opacity criterion of Franco and Cox (1986) and thus form molecular clouds. The resultant clouds have masses larger than 100,000 solar masses, dimensions of several hundred parsecs, and a separation larger than 1 kpc. In contrast, at 20 kpc from the galactic center the opacity criterion is never fulfilled.

Tenorio-Tagle, G.; Palous, J.

1987-01-01

330

CCD soft X-ray observations of the Puppis a supernova remnant  

NASA Technical Reports Server (NTRS)

We present the first images and spectra of an astronomical object, other than the Sun, acquired with a charge coupled device (CCD) imaging X-ray spectrometer. During a 230 s sounding rocket observation, we have acquired moderate-resolution spectra and moderate-resolution images of a portion of the Pup A supernova remnant (SNR). Based on these data, we conclude that the X-ray spectrum of Pup A is inconsistent with any single-temperature equilibrium or nonequilibrium plasma model. We find evidence for variations in the emitting plasma on scales as small as 5.0 min and as large as 30.0 min. The spatial structure of the spectral variations in the remnant is found to be inconsistent with the standard Sedov model for the evolution of a SRN into a homogeneous interstellar medium (ISM). We suggest that the remnant is expanding into a region of the ISM having a density of approximately 1 cm(exp -3) with inhomogeneities on the order of 50%. We have found evidence for the presence of a knot of plasma enriched in neon, but require more data to be conclusive.

Berthiaume, G. D.; Burrows, D. N.; Garmire, G. P.; Nousek, J. A.

1994-01-01

331

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

NASA Astrophysics Data System (ADS)

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

Wang, Wei; Li, Zhuo

2014-07-01

332

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

NASA Astrophysics Data System (ADS)

We present a survey of the X-ray-emitting ejecta in the Cassiopeia A supernova remnant (SNR) based on an extensive analysis of over 6000 spectral regions extracted on 2farcs5-10'' angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age, and the implied mass coordinates, are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks following reverse shock interaction with ejecta inhomogeneities. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray-emitting ejecta and also show the distribution of the mass of various elements over the remnant. An upper limit to the total shocked Fe mass visible in X-rays appears to be roughly 0.13 M ?, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si burning and that possibly associated with ?-rich freezeout, with a mass ratio of approximately 2:1. Essentially all of the observed Fe (both components) lies well outside the central regions of the SNR, possibly having been ejected by hydrodynamic instabilities during the explosion. We discuss this and its implications for the neutron star kick.

Hwang, Una; Laming, J. Martin

2012-02-01

333

Discovery of X-ray emission from two southern supernova remnants  

NASA Technical Reports Server (NTRS)

Two soft X-ray sources positionally coincident with the supernova remnants PKS 1209-52 and RCW 103 have been discovered by using the A-2 experiment on HEAO 1. Their measured fluxes are, respectively, about 1.4 x 10 to the -10th erg/cm-sec (0.2-1.0 keV) and about 1.8 x 10 to the -10th erg/cm-sec (0.6-2.0 keV). Spectral data are used to derive physical parameters for each remnant. For PKS 1209-52 the parameters are suggestive of the remnant's being in an advanced evolutionary phase, with shock-heated interstellar material producing the soft X-ray emission. RCW 103, in contrast, is known from radio and optical data to be in an earlier evolutionary phase, and the soft X-ray flux is most likely due to emission originating in a reflected shock wave or in plasma evaporated from shock-heated interstellar clouds.

Tuohy, I. R.; Cordova, F. A.; Garmire, G. P.; Mason, K. O.; Charles, P. A.; Walter, F. M.; Clark, D. H.

1979-01-01

334

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

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

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

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

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

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

2004-01-01

335

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

PubMed

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

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

2011-01-01

336

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

337

A CHANDRA X-RAY SURVEY OF EJECTA IN THE CASSIOPEIA A SUPERNOVA REMNANT  

SciTech Connect

We present a survey of the X-ray-emitting ejecta in the Cassiopeia A supernova remnant (SNR) based on an extensive analysis of over 6000 spectral regions extracted on 2.''5-10'' angular scales using the Chandra 1 Ms observation. We interpret these results in the context of hydrodynamical models for the evolution of the remnant. The distributions of fitted temperature and ionization age, and the implied mass coordinates, are highly peaked and suggest that the ejecta were subjected to multiple secondary shocks following reverse shock interaction with ejecta inhomogeneities. Based on the fitted emission measure and element abundances, and an estimate of the emitting volume, we derive masses for the X-ray-emitting ejecta and also show the distribution of the mass of various elements over the remnant. An upper limit to the total shocked Fe mass visible in X-rays appears to be roughly 0.13 M{sub Sun }, which accounts for nearly all of the mass expected in Fe ejecta. We find two populations of Fe ejecta, that associated with normal Si burning and that possibly associated with {alpha}-rich freezeout, with a mass ratio of approximately 2:1. Essentially all of the observed Fe (both components) lies well outside the central regions of the SNR, possibly having been ejected by hydrodynamic instabilities during the explosion. We discuss this and its implications for the neutron star kick.

Hwang, Una [Goddard Space Flight Center, Greenbelt, MD (United States); Laming, J. Martin, E-mail: Una.Hwang-1@gsfc.nasa.gov, E-mail: laming@nrl.navy.mil [Naval Research Laboratory, Code 7674L, Washington, DC 20375 (United States)

2012-02-20

338

Spitzer Observations of the Type Ia Supernova Remnant N103B: A Type Ia with CSM Interaction?  

NASA Astrophysics Data System (ADS)

A small but growing subclass of Type Ia supernovae show signs of interaction with material in a circumstellar medium (CSM), likely the result of significant pre-supernova mass loss from the progenitor system. Among Type Ia supernova remnants (SNRs), only the remnant of Kepler's supernova has been shown to be interacting with a dense CSM. We report results from Spitzer observations of SNR 0509-68.7, also known as N103B, a young Type Ia supernova remnant in the Large Magellanic Cloud that shows interaction with a dense medium in its western hemisphere. Our images show that N103B has strong IR emission from warm dust in the post-shock environment. The post-shock gas density we derive, 45 cm$^{-3}$, is much higher than in other Type Ia remnants in the LMC, though a lack of spatial resolution may bias measurements towards regions of higher than average density. Thisdensity is similar to that in Kepler's SNR. Optical images show H$\\alpha$ emission along the entire periphery of the western portion of the shock, with [O III] and [S II] lines emitted from a few dense clumps of material where the shock has become radiative. The dust is silicate in nature, though standard silicate dust models fail to reproduce the ``18 $\\mu$m'' silicate feature that peaks instead at 17.3 $\\mu$m. We propose that the dense material is circumstellar material lost from the progenitor system, as with Kepler. If the CSM interpretation is correct, this remnant would become the second member, along with Kepler, of a class of Type Ia remnants characterized by interaction with a dense CSM hundreds of years post-explosion. A lack of N enhancement eliminates symbiotic AGB progenitors. The white dwarf companion must have been relatively unevolved at the time of the explosion.

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

2014-08-01

339

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

340

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

NASA Technical Reports Server (NTRS)

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

341

Swift/BAT detection of hard X-rays from Tycho;s Supernova Remnant: Evidence for 44Ti  

NASA Astrophysics Data System (ADS)

We report Swift/BAT survey observations of the Tycho supernova remnant, performed over a period of 104 month. A total exposure of 19.6 Ms was used to detect significant hard X-ray emission up to about 100 keV. Excess emission above this continuum in the 60-85 keV band was found, consistent with line emission from radioactive 44T. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type II and Type Ia supernova, with emphasis on the production of 44Ti.

Hartmann, Dieter; Troja, Eleonora; Baumgartner, Wayne H.; Markwardt, Craig; Barthelmy, Scott Douglas; Gehrels, Neil; Segreto, Alberto; La Parola, Valentina

2014-06-01

342

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

343

SRAO CO Observation of Supernova Remnants in l = 70° to 190°  

NASA Astrophysics Data System (ADS)

We present the results 12CO J = 1-0 line observations of eleven Galactic supernova remnants (SNRs) between l = 70° and 190° obtained using the Seoul Radio Astronomy Observatory (SRAO) 6-m radio telescope. We detected CO emission towards most of the remnants. In seven SNRs, molecular clouds show a good spatial relation with their radio morphology: G73.9+0.9, G84.2-0.8, G85.4+0.7, G85.9-0.6, G93.3+6.9 (DA530), 94.0+1.0 (3C 434.1), and G182.4+4.3. Two SNRs are particularly interesting. In G85.4+0.7, there is a filamentary molecular cloud aligned along the south-east boundary of the remnant. This cloud extends to the nearby Hii region G84.9+0.5. If the molecular cloud is associated with both the Hii region and the SNR, the distance to the SNR would be 5-7 kpc. In 3C 434.1, there is a large molecular cloud blocking the western half of the remnant where the radio continuum emission is faint. The cloud shows a very good spatial correlation with radio continuum features, which strongly suggests the physical association of the cloud with the SNR. This gives a distance of 3 kpc to the SNR. We performed 12CO J = 2-1 line observations of this cloud using Kölner Observatorium für Sub-Millimeter Astronomie (KOSMA) 3-m telescope and found a region where the 12CO J = 2-1/1-0 line ratio is high. We present a hydrodynamic model showing that 3C434.1 could have resulted from a SN explosion occurred just outside the boundary of a thin, molecular cloud.

Jeong, Il-Gyo; Koo, Bon-Chul

2014-01-01

344

Gamma-Ray Observations of the Supernova Remnant RX J0852.0- 4622 with the Fermi LAT.  

National Technical Information Service (NTIS)

We report on gamma-ray observations of the supernova remnant (SNR) RX J0852.0.4622 with the Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope. In the Fermi LAT data, we find a spatially extended source at the location of the SNR. The e...

A. Allafort F. Giordano J. Ballet S. Funk T. Tanaka

2011-01-01

345

Crushing of interstellar gas clouds in supernova remnants. I. The role of thermal conduction and radiative losses  

Microsoft Academic Search

We model the hydrodynamic interaction of a shock wave of an evolved supernova remnant with a small interstellar gas cloud like the ones observed in the Cygnus loop and in the Vela SNR. We investigate the interplay between radiative cooling and thermal conduction during cloud evolution and their effect on the mass and energy exchange between the cloud and the

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

2005-01-01

346

Low-Frequency Survey of the Galactic Plane Near l = 11 degs: Discovery of Three New Supernova Remnants.  

National Technical Information Service (NTIS)

We have imaged a1 deg(caret)2 field centered on the known Galactic supernova remnant (SNR) G11.2-0.3 at 74, 330, and 1465 MHz with the Very Large Array radio telescope and 235 MHz with the Giant Metrewave Radio Telescope. The 235, 330, and 1465 MHz data h...

C. L. Brogan C. R. Tam K. E. Devine N. E. Kassim T. J. Lazio

2004-01-01

347

The Expansion Rate, Age, and Distance of the Supernova Remnant G266.2?1.2  

NASA Astrophysics Data System (ADS)

We reprocessed and analyzed the 2003 and 2008 Chandra ACIS data for the supernova remnant G266.2?1.2. The data for two adjacent annular wedges along a relatively bright and narrow portion of the northwestern rim indicate that it has moved by about 2.39 ± 0.57 arcsec over a period of 5.652 yr. The corresponding expansion rate (0.42 ± 0.10 arcsec/yr or 13.6 ± 5.7 %/kyr) is about half of the rate reported for an analysis of XMM data from a similar region of the remnant over a similar time interval (Katsuda, Tsunemi & Mori, 2008). A hydrodynamic analysis was performed using the models of Truelove & McKee (1999). Many scenarios were considered using broad ranges of initial kinetic energies, ejecta masses, ejecta mass density distributions, ambient densities, and evolutionary states. The results were constrained by the Chandra expansion rate (assuming it is representative of the remnant as a whole), an inferred lower limit on the forward shock speed, an upper limit on the inferred thermal X-ray emission, and energy considerations. The results of this analysis suggest that G266.2?1.2 is most likely between 2.4 and 5.1 kyr old, whether or not it was produced by a type Ia or type II event. If the remnant is expanding into the material shed by a steady stellar wind instead of a uniform ambient medium, then it could be older by a factor of up to 1.5. In no case is the remnant expected to be younger than 2.2 kyr. Therefore, it is too old to be associated with emission from the decay of Ti-44 or with features in the abundance of nitrate in South Pole ice core samples. The hydrodynamic results provide only a weak constraint on the distance of G266.2?1.2. An analysis of previously-published distance estimates and constraints suggests that the remnant is between about 0.5 and 1.0 kpc. This limitation does not significantly affect the estimate of the age. We adopt the distance of thecloser of two groups of material in the Vela Molecular Ridge (i.e. 0.7 ± 0.2 kpc, Liseau et al. 1992). This distance is consistent with the progenitor having been a member of the Vel OB1 association (Eggen 1982).

Allen, Glenn E.; DeLaney, Tracey; Filipovic, Miroslav D; Houck, John C.; Pannuti, Thomas; Stage, Michael D.

2014-08-01

348

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

349

Nonthermal X-Ray Emission from the Shell-Type Supernova Remnant G347.3-0.5  

NASA Technical Reports Server (NTRS)

Recent Advanced Spacecraft for Cosmology Astrophysics (ASCA) observations of G347.3-0.5, a supernova remnant (SNR) discovered in the ROSAT All-Sky Survey, reveal nonthermal emission from a region along the northwestern shell. Here we report on new pointed ASCA observations of G347.3-0.5 that confirm this result for all the bright shell regions and also reveal similar emission, although with slightly different spectral properties, from the remainder of the SNR. Curiously, no thermal X-ray emission is detected anywhere in the remnant. We derive limits on the amount of thermal emitting material present in G347.3-0.5 and present new radio continuum, CO, and infrared results that indicate that the remnant is distant and of moderate age. We show that our observations are broadly consistent with a scenario that has most of the supernova remnant shock wave still within the stellar wind bubble of its progenitor star, while part of it appears to be interacting with denser material. A point source at the center of the remnant has spectral properties similar to those expected for a neutron star and may represent the compact relic of the supernova progenitor.

Slane, Patrick O.; Gaensler, Bryan M.; Dame, T. M.; Hughes, John P.; Plucinsky, Paul P.; Green, Anne

2002-01-01

350

MEASURING DUST PRODUCTION IN THE SMALL MAGELLANIC CLOUD CORE-COLLAPSE SUPERNOVA REMNANT 1E 0102.2-7219  

SciTech Connect

We present mid-infrared spectral mapping observations of the core-collapse supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud using the InfraRed Spectrograph on the Spitzer Space Telescope. The remnant shows emission from fine structure transitions of neon and oxygen as well as continuum emission from dust. Comparison of the mid-IR dust emission with observations at X-ray, radio, and optical wavelengths shows that the dust is associated with the supernova ejecta and is thus newly formed in the remnant. The spectrum of the newly formed dust is well reproduced by a model that includes 3 x 10{sup -3} M {sub sun} of amorphous carbon dust at 70 K and 2 x 10{sup -5} M {sub sun} of Mg{sub 2}SiO{sub 4} (forsterite) at 145 K. Our observations place a lower limit on the amount of dust in the remnant since we are not sensitive to the cold dust in the unshocked ejecta. We compare our results to observations of other core-collapse supernovae and remnants, particularly Cas A where very similar spectral mapping observations have been carried out. We observe a factor of {approx}10 less dust in E 0102 than seen in Cas A, although the amounts of amorphous carbon and forsterite are comparable. Finally, we present evidence suggesting that the grain size distribution of the newly formed dust in E 0102 has been altered by the hot plasma behind the reverse shock.

Sandstrom, Karin M. [Astronomy Department, 601 Campbell Hall, University of California, Berkeley, CA 94720 (United States); Bolatto, Alberto D. [Department of Astronomy and Laboratory for Millimeter-wave Astronomy, University of Maryland, College Park, MD 20742 (United States); Stanimirovic, Snezana [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Van Loon, Jacco Th. [Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG (United Kingdom); Smith, J. D. T. [Ritter Astrophysical Research Center, University of Toledo, OH 43603 (United States)], E-mail: karin@astro.berkeley.edu

2009-05-10

351

The many sides of RCW 86: a Type Ia supernova remnant evolving in its progenitor's wind bubble  

NASA Astrophysics Data System (ADS)

We present the results of a detailed investigation of the Galactic supernova remnant RCW 86 using the XMM-Newton X-ray telescope. RCW 86 is the probable remnant of SN 185 A.D., a supernova that likely exploded inside a wind-blown cavity. We use the XMM-Newton Reflection Grating Spectrometer to derive precise temperatures and ionization ages of the plasma, which are an indication of the interaction history of the remnant with the presumed cavity. We find that the spectra are well fitted by two non-equilibrium ionization models, which enables us to constrain the properties of the ejecta and interstellar matter plasma. Furthermore, we performed a principal component analysis on EPIC MOS and pn data to find regions with particular spectral properties. We present evidence that the shocked ejecta, emitting Fe K and Si line emission, are confined to a shell of approximately 2 pc width with an oblate spheroidal morphology. Using detailed hydrodynamical simulations, we show that general dynamical and emission properties at different portions of the remnant can be well reproduced by a Type Ia supernova that exploded in a non-spherically symmetric wind-blown cavity. We also show that this cavity can be created using general wind properties for a single degenerate system. Our data and simulations provide further evidence that RCW 86 is indeed the remnant of SN 185, and is the likely result of a Type Ia explosion of single degenerate origin.

Broersen, Sjors; Chiotellis, Alexandros; Vink, Jacco; Bamba, Aya

2014-07-01

352

Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT.  

PubMed

Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants. PMID:19574346

Abdo, A A; Ackermann, M; Ajello, M; Anderson, B; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Bignami, G F; Blandford, R D; Bloom, E D; 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; Casandjian, J M; Cecchi, C; Celik, O; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; Dermer, C D; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giommi, P; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Gwon, C; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hughes, R E; Jóhannesson, G; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Marelli, M; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Pierbattista, M; Piron, F; Porter, T A; Primack, J R; Rainò, S; Rando, R; Ray, P S; Razzano, M; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Sgrò, 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 G; Thompson, D J; Tibaldo, L; Tibolla, O; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Van Etten, A; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wang, P; Watters, K; Winer, B L; Wolff, M T; Wood, K S; Ylinen, T; Ziegler, M

2009-08-14

353

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

354

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

NASA Astrophysics Data System (ADS)

The double pulsar system PSR J0737-3039A/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 J0737-3039A, 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

355

THE DOUBLE PULSAR: EVIDENCE FOR NEUTRON STAR FORMATION WITHOUT AN IRON CORE-COLLAPSE SUPERNOVA  

SciTech Connect

The double pulsar system PSR J0737-3039A/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 J0737-3039A, to be a near-orthogonal rotator with an average separation between its spin and magnetic axes of 90 Degree-Sign {+-} 11 Degree-Sign {+-} 5 Degree-Sign . Furthermore, we find a mean 95% upper limit on the misalignment between its spin and orbital angular momentum axes of 3. Degree-Sign 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.; Kramer, M.; Stappers, B. W.; Lyne, A. G. [School of Physics and Astronomy, University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Oxford Road, Manchester M13 9PL (United Kingdom)] [School of Physics and Astronomy, University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Oxford Road, Manchester M13 9PL (United Kingdom); Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)] [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Breton, R. P. [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)] [School of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26505 (United States)] [Department of Physics, West Virginia University, Morgantown, WV 26505 (United States); Freire, P. C. C. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany)] [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Possenti, A. [INAF-Osservatorio Astronomico di Cagliari, Loc. Poggio dei Pini, I-09012 Capoterra (Italy)] [INAF-Osservatorio Astronomico di Cagliari, Loc. Poggio dei Pini, I-09012 Capoterra (Italy); Kaspi, V. M. [Department of Physics, McGill University, Ernest Rutherford Physics Building, 3600 University Street, Montreal, QC H3A 2T8 (Canada)] [Department of Physics, McGill University, Ernest Rutherford Physics Building, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Manchester, R. N., E-mail: ferdman@jb.man.ac.uk [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping, NSW 1710 (Australia)

2013-04-10

356

The MIT spectroscopy investigations on AXAF and the study of supernova remnants  

NASA Technical Reports Server (NTRS)

The MIT High Resolution X-Ray Spectroscopy experiment on the AXAF, which will study physical conditions in celestial sources by means of detailed measurements of emission and absorption features in their spectra, involves two complementary dispersive instruments: Bragg Crystal Spectrometer (BCS) and High Energy Transmission Grating (HETG). This paper discusses the principles of operation of BCS and HETG and the results that will be obtained by these instruments. Measurements of individual line strengths obtained by the AXAF spectrometers will allow the application of plasma diagnostic techniques to a study of the detailed physical conditions in celestial objects, particularly in the optically thin plasma of supernova remnants, which is particularly well suited to the application of plasma diagnostics.

Canizares, C. R.; Bradt, H. V. D.; Clark, G. W.; Joss, P. C.; Levine, A. M.; Lewin, W. H. G.; Markert, T. H.; Mayer, W.; Fabian, A. C.; Woodgate, B. E.

1987-01-01

357

Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant  

NASA Technical Reports Server (NTRS)

Imaging and spectral observations of the Puppis A supernova remnant (SNR) with the Spitzer Space Telescope confirm that its IR emission is dominated by the thermal continuum emission of swept-up interstellar dust which is collisionally heated by the X-ray emitting gas of the SNR. Line emission is too weak to affect the fluxes measured in broadband observations, and is poorly correlated with the IR or X-ray emission. Modeling of spectra from regions both in the SNR and in the associated ISM show that the ubiquitous polycyclic aromatic hydrocarbons (PAHs) of the ISM are destroyed within the SNR, along with nearly 25% of the mass of graphite and silicate dust grains.

Arendt, Richard G.; Dwek, Eli,; Blair, William P.; Ghavamian, Parviz; Long, Knox S.

2010-01-01

358

A possible explanation of photon emission from supernova remnants by jitter radiation  

NASA Astrophysics Data System (ADS)

We investigate a possibility that non-thermal X-ray emission in a supernova remnant(SNR) is produced by jitter radiation, which is the analogue of synchrotron radiation in small-scale random magnetic fields. We can fit the multi-wavelength data of SNRs RX J1713.7-3946 (G347.3-0.5) and RX J0852.0-4622 (G266.6-1.2) by constructing pure jitter and inverse Compton (IC) emission models. We find that the physical fit parameters of random magnetic fields take values of several tens of ?G strength and of the order of ˜107 cm correlation length. These properties of random magnetic fields in collisionless shock of SNRs are discussed.

Ogasawara, T.; Yoshida, T.; Yanagita, S.; Kifune, T.

2007-06-01

359

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

360

Two GeV-TeV Supernova Remnants without Associated Neutral and Molecular Clouds  

NASA Astrophysics Data System (ADS)

TeV gamma ray emissions have been detected at the directions of supernova remnants (SNRs) W51C and Tycho SNR. We analyze the Hi absorption spectra towards W51C, Tycho SNR and their nearby compact sources. We conclude that W51C is at a distance of about 4.3 kpc and Tycho SNR has a distance of 2.5 ~ 3.0 kpc. Our study detects high-velocity Hi clouds which coincide with star formation region W51B, but finds that the clouds are behind W51B which argues against previous claims that W51C has shocked the high velocity Hi clouds. We argue that Tycho SNR is naked Ia SNR (lack of evidence of interacting with adjacent neutral and molecular cloud). This gives two examples that the very high gamma ray emission from SNRs does not likely originate from SNR-cloud interaction.

Tian, W.; Leahy, D.; Zhu, H.; Su, H.

2014-02-01

361

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-Pérot 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

362

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-Pérot 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

363

Dense Gas Towards the RX J1713.7-3946 Supernova Remnant  

NASA Astrophysics Data System (ADS)

We present results from a Mopra 7 mm-wavelength survey that targeted the dense gas-tracing CS(1-0) transition towards the young ?-ray-bright supernova remnant, RX J1713.7-3946 (SNR G 347.3-0.5). In a hadronic ?-ray emission scenario, where cosmic ray (CR) protons interact with gas to produce the observed ?-ray emission, the mass of potential CR target material is an important factor. We summarise newly discovered dense gas components, towards Cores G and L, and Clumps N1, N2, N3, and T1, which have masses of 1 - 104 M?. We argue that these components are not likely to contribute significantly to ?-ray emission in a hadronic ?-ray emission scenario. This would be the case if RX J1713.7-3946 were at either the currently favoured distance of ~1 kpc or an alternate distance (as suggested in some previous studies) of ~6 kpc.

Maxted, Nigel I.; Rowell, Gavin P.; Dawson, Bruce R.; Burton, Michael G.; Fukui, Yasuo; Lazendic, Jasmina; Kawamura, Akiko; Horachi, Hirotaka; Sano, Hidetoshi; Walsh, Andrew J.; Yoshiike, Satoshi; Fukuda, Tatsuya

2013-11-01

364

A VLA Low Frequency Survey of the Supernova Remnant Population in M83  

NASA Astrophysics Data System (ADS)

We present low frequency observations of the grand design spiral galaxy, M83, using the C and L bands of the Karl G. Jansky Very Large Array (VLA). With recent optical (HST) and X-ray (Chandra) observations and utilizing the newly expanded bandwidth of the VLA, we are exploring the radio spectral properties of the more than 150 radio point sources in M83. These observations allow us to probe the evolution of supernova remnants (SNRs) and to find previously undiscovered SNRs. These observations represent the fourth epoch of deep VLA observations of M83. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities.

Stockdale, Christopher; Pritchard, T. A.; Blair, W. P.; Cowan, J. J.; Godfrey, L.; Miller-Jones, J.; Kuntz, K. D.; Long, K. S.; Maddox, L. A.; Plucinsky, P. P.; Soria, R.; Whitmore, B. C.; Winkler, P. F.

2014-01-01

365

Detection of Class I Methanol (CH3OH) Maser Candidates in Supernova Remnants  

NASA Astrophysics Data System (ADS)

We have used the Karl G. Jansky Very Large Array to search for 36 GHz and 44 GHz methanol (CH3OH) lines in a sample of 21 Galactic supernova remnants (SNRs). Mainly the regions of the SNRs with 1720 MHz OH masers were observed. Despite the limited spatial extent covered in our search, methanol masers were detected in both G1.4-0.1 and W28. Additional masers were found in Sgr A East. More than 40 masers were found in G1.4-0.1, which we deduce are due to interactions between the SNR and at least two separate molecular clouds. The six masers in W28 are associated with the molecular cloud that is also associated with the OH maser excitation. We discuss the possibility that the methanol maser may be more numerous in SNRs than the OH maser, but harder to detect due to observational constraints.

Pihlström, Y. M.; Sjouwerman, L. O.; Frail, D. A.; Claussen, M. J.; Mesler, R. A.; McEwen, B. C.

2014-04-01

366

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

367

A neutron star with a carbon atmosphere in the Cassiopeia A supernova remnant.  

PubMed

The surface of hot neutron stars is covered by a thin atmosphere. If there is accretion after neutron-star formation, the atmosphere could be composed of light elements (H or He); if no accretion takes place or if thermonuclear reactions occur after accretion, heavy elements (for example, Fe) are expected. Despite detailed searches, observations have been unable to confirm the atmospheric composition of isolated neutron stars. Here we report an analysis of archival observations of the compact X-ray source in the centre of the Cassiopeia A supernova remnant. We show that a carbon atmosphere neutron star (with low magnetic field) produces a good fit to the spectrum. Our emission model, in contrast with others, implies an emission size consistent with theoretical predictions for the radius of neutron stars. This result suggests that there is nuclear burning in the surface layers and also identifies the compact source as a very young ( approximately 330-year-old) neutron star. PMID:19890325

Ho, Wynn C G; Heinke, Craig O

2009-11-01

368

Detection of the characteristic pion-decay signature in supernova remnants.  

PubMed

Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs. PMID:23413352

Ackermann, M; Ajello, M; Allafort, A; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Bechtol, K; Bellazzini, R; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Busetto, G; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chaves, R C G; Chekhtman, A; Cheung, C C; Chiang, J; Chiaro, G; Cillis, A N; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbel, S; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; do Couto e Silva, E; Drell, P S; Drlica-Wagner, A; Falletti, L; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Germani, S; Giglietto, N; Giommi, P; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hayashi, K; Hays, E; Hewitt, J W; Hill, A B; Hughes, R E; Jackson, M S; Jogler, T; Jóhannesson, G; Johnson, A S; Kamae, T; Kataoka, J; Katsuta, J; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Madejski, G M; Massaro, F; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mignani, R P; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orienti, M; Orlando, E; Ormes, J F; Paneque, D; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Rainò, S; Rando, R; Razzano, M; Razzaque, S; Reimer, A; Reimer, O; Ritz, S; Romoli, C; Sánchez-Conde, M; Schulz, A; Sgrò, C; Simeon, P E; Siskind, E J; Smith, D A; Spandre, G; Spinelli, P; Stecker, F W; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Takahashi, T; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Thorsett, S E; Tibaldo, L; Tibolla, O; Tinivella, M; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Werner, M; Winer, B L; Wood, K S; Wood, M; Yamazaki, R; Yang, Z; Zimmer, S

2013-02-15

369

DISCOVERY OF THE SMALL-DIAMETER, YOUNG SUPERNOVA REMNANT G354.4+0.0  

SciTech Connect

We report the discovery of a shell-like structure G354.4+0.0 of size 1.'6 that shows the morphology of a shell supernova remnant (SNR). Part of the structure shows polarized emission in a NRAO VLA sky survey map. Based on 330 MHz and 1.4 GHz Giant Metrewave Radio Telescope observations and existing observations at higher frequencies, we conclude that the partial shell structure showing synchrotron emission is embedded in an extended H II region of size {approx}4'. The spectrum of the diffuse H II region turns over between 1.4 GHz and 330 MHz. The H I absorption spectrum shows this objected to be located more than 5 kpc from Sun. Based on its morphology, non-thermal polarized emission, and size, this object is one of the youngest SNRs discovered in the Galaxy with an estimated age of {approx}100-500 yr.

Roy, Subhashis [NCRA-TIFR, Pune 411007 (India); Pal, Sabyasachi, E-mail: roy@ncra.tifr.res.in, E-mail: sabya@csp.res.in [Indian Centre for Space Physics, Kolkata 700084 (India)

2013-09-10

370

Cosmic ray acceleration in supernova remnants and the FERMI/PAMELA data  

SciTech Connect

We discuss recent observations of high energy cosmic ray positrons and electrons in the context of hadronic interactions in supernova remnants (SNRs), the suspected accelerators of galactic cosmic rays. Diffusive shock acceleration can harden the energy spectrum of secondary positrons relative to that of the primary protons and electrons and thus explain the rise in the positron fraction observed by PAMELA above 10 GeV. We normalize the hadronic interaction rate by holding pion decay to be responsible for the gamma rays detected by HESS from some SNRs. By simulating the spatial and temporal distribution of SNRs in the Galaxy according to their known statistics, we are able to then fit the electron (plus positron) energy spectrum measured by Fermi. It appears that IceCube has good prospects for detecting the hadronic neutrino fluxes expected from nearby SNRs.

Ahlers, Markus; Mertsch, Philipp; Sarkar, Subir [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Oxford OX1 3NP (United Kingdom)

2009-12-15

371

Large and Energetic Supernova Remnant Candidates Are Jet-Inflated Bubbles  

NASA Astrophysics Data System (ADS)

Among optically selected supernova remnants in nearby galaxies a few are exceptionally large (¿ 200 pc), presumably very energetic (¿ E52 erg) and have therefore been associated with putative "hypernova" events. Here we show that the extreme cases are not due to SN explosions, but rather harbour luminous X-ray binaries (often of the ULX variety) in their centers that also emit powerful relativistic winds/jets. The jets display mechanical powers of up to some E40 erg/s that can inflate supersonically expanding, huge interstellar bubbles with diameters reaching 1 kpc. The sample includes the famous case of SS433 with its associated radio nebula W50 as well as the SNR candidate S26 in the Sculptor galaxy NGC 7793 which we recently discovered to display X-ray/optical/radio hot spots and jet-inflated lobes around a central (micro-)quasar strikingly resembling a scaled-down version of a FRII-type radio galaxy

Pakull, Manfred

372

New Constraints on the Age of the Ultraluminous Supernova Remnant in NGC 4449  

NASA Astrophysics Data System (ADS)

NGC 4449 is a Magellanic irregular galaxy which lies at a distance of about 5 Mpc. It contains one exceedingly luminous young supernova remnant (SNR) identified by radio, optical, and X-ray means in the late-1970's that is readily observable even at this distance. This SNR shows a number of similarities to the galactic SNR Cas A, including high expansion velocities and enriched ejecta indicative of the remnant of a massive core-collapse supernova. However, the luminosity of this SNR is orders of magnitude higher than Cas A, presumably due both to its youth and expansion into a dense circumstellar environment. Because of its distance, no detailed spatial structure is resolvable for this SNR. We report new UV/optical HST data and ground-based optical data for this unique object. An HST/Faint Object Camera image shows the SNR to be only slightly broadened above a stellar source, allowing us to place an upper limit of 0.028'' (or 0.6 pc) on the diameter of the SNR. Improved S/N spectral line profiles from both the HST/Faint Object Spectrograph and the MDM Observatory in Arizona show broad wings on many lines, indicative of expansion velocities in excess of 6000 km s{-1}. Taken together, these data indicate an upper limit of 100 years on the age of this object (possibly less if some deceleration has occurred), or roughly 1/3--1/4 the age of Cas A. In addition to O-rich ejecta, strong lines of Ne, S, A, Mg, Fe, and possibly C and Si are seen but with somewhat different line widths suggestive of asymmetry in chemically distinct ejecta or possibly different levels of collisional de-excitation. This work is supported by STScI grant GO-06118.01-94A to the Johns Hopkins University.

Blair, W. P.; Fesen, R. A.

1998-12-01

373

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

374

Einstein observations of the Vela supernova remnant - The spatial structure of the hot emitting gas  

NASA Technical Reports Server (NTRS)

Spatially resolved (aproximately 1 arcmin) X-ray maps of the Vela supernova remnant have been constructed in two spectral bands, 0.2-1.0 keV and 0.8-2.0 keV, from a series of 36 separate observations with the Imaging Proportional Counter of the Einstein Observatory. The maps exhibit substantial structure on all angular scales. Spectral analysis shows that the emission from the remnant can be consistently described as thermal radiation from hot gas which is nonuniform in density and temperature, but which is in approximate pressure equilibrium. It is found that p/k is approximately 3-4 x 10 to the 5th/cu cm K. The soft X-ray emission exhibits a high degree of correlation with the optical filamentary structure, in the sense that the most prominent filaments either tightly surround or are coincident with the brightest X-ray regions. This suggests that the softest X-radiation may originate in 'warm' gas which is evaporated from the denser clouds responsible for the optical and ultraviolet filaments. Such an interpretation is quantitatively investigated, and shown to be only marginally consistent with the observations.

Kahn, S. M.; Gorenstein, P.; Harnden, F. R., Jr.; Seward, F. D.

1985-01-01

375

IUE spectra and optical imaging of the oxygen-rich supernova remnant N132D  

NASA Technical Reports Server (NTRS)

We present new optical Charge Coupled Devices (CCD) interference filter imagery and International Ultraviolet Explorer (IUE) spectroscopy for the oxygen-rich supernova remnant N132D in the Large Magellanic Cloud. The optical images show a wealth of structure, and comparison with an archival Einstein High Resolution Imager (HRI) X-ray image shows that a few optical features have X-ray counter-parts, but in general there is little correlation between X-ray and optical features. The IUE spectra at two positions show strong lines of carbon and oxygen, with lines of neon, magnesium, silicon, and helium also present and variable in relative intensities. We use optical data for N132D from Dopita & Tuohy (1984) with our UV observations to compare with shock models (both with and without thermal conduction) and X-ray photoionization model calculations. While none of the model fits is entirely satisfactory, the generally weak UV emission relative to optical disagrees with the general character of shock model predictions and indicates that photoionization is the dominant excitation mechanism for the UV/optical emission. This conclusion is similar to what was found for E0102 - 7219, the oxygen-rich remnant in the Small Magellanic Cloud. We derive rough abundances for the emitting material in N132D, compare to stellar nucleosynthesis models, and discuss the implications for its precursor. A precursor near 20 solar mass is consistent with the data.

Blair, William P.; Raymond, John C.; Long, Knox S.

1994-01-01

376

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

377

EXPECTED GAMMA-RAY EMISSION OF SUPERNOVA REMNANT SN 1987A  

SciTech Connect

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{sub d} {approx} 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 {gamma}-ray energy flux at TeV energies at the current epoch is nearly {epsilon}{sub {gamma}} F{sub {gamma}} {approx} 4 x 10{sup -13} erg cm{sup 2} s{sup -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. [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Avenue, 677980 Yakutsk (Russian Federation); Voelk, H. J., E-mail: ksenofon@ikfia.ysn.ru [Max Planck Institut fuer Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)

2011-05-01

378

CCD mosaic images of the supernova remnant 3C 400.2  

NASA Technical Reports Server (NTRS)

We have constructed CCD mosaic images of the old Galactic supernova remnant 3C 400.2 in lines of H-alpha + forbidden N II, forbidden S II, and forbidden O III, plus a continuum band. These are the first CCD images covering the full extent of this remnant, and they reveal significantly more nebulosity than the deepest photographic plates. Comparison with radio and X-ray images indicates dramatically different morphology in the three regimes. The optical images both in H-alpha + forbidden N II and in forbidden S II show an almost complete, irregular shell of emission, with a diameter of about 16 arcmin, little over half that of the radio shell, while the X-ray structure is a centrally peaked ellipsoid. Approximate values for optical line fluxes are obtained; we estimate L(H-alpha) about 3 x 10 exp 35 ergs/s, roughly three times the X-ray luminosity. We also report a previously uncataloged planetary nebula southwest of 3C 400.2.

Winkler, P. F.; Olinger, Todd M.; Westerbeke, Scott A.

1993-01-01

379

Hadronic Scenarios for Gamma-Ray Emission from Three Supernova Remnants Interacting with Molecular Clouds  

NASA Astrophysics Data System (ADS)

GeV ?-rays detected with the large area telescope on board the Fermi Gamma-ray space telescope in the direction of HB21, MSH 17-39 and G337.0-0.1 have been recently reported. The three supernova remnants (SNRs) show interactions with molecular clouds, and they are effective gamma-ray emitters as the relativistic protons accelerated by the SNR shocks inelastically colliding with the dense gas in the clouds. The origin of the observed ?-rays for the three remnants is investigated in the scenario of the diffusive shock acceleration. In the model, a part of the SNR shock transmits into the nearby molecular clouds, and the shock velocity is greatly reduced. As a result, a shock with a relatively low Alfvén Mach number is generated, and the spectra of the accelerated protons and the ?-ray photons produced via proton-proton interaction can be obtained. The results show that the observed ?-ray spectra for the three SNRs interacting with the molecular clouds can be reproduced. It can be concluded that the hadronic origin of the ?-rays for the three SNRs is approved, and the ability of SNR shocks to accelerate protons is also supported.

Yu, Huan; Fang, Jun; Zhang, Li

2014-04-01

380

Supernova Remnants and Nucleosynthesis (fos 30): Augmentation Cycle 2 Observations - Imaging  

NASA Astrophysics Data System (ADS)

Overall program: UV and optical spectra of four supernova remnants (SNRs) will be used to study a number of problems related to abundances, grain destruction, interstellar medium properties and physical conditions in SNR shocks. Representatives of three of the main classes of SNRs (Crab-nebula like, Balmer-line and "normal") will be studied in the LMC, where reasonably low reddening permits UV observations. An oxygen-rich SNR in NGC 4449 will be observed, taking advantage of the small FOS slits to isolate the SNR from surrounding H II emission. Two M33 SNRs that were previously part of this proposal have been dropped due to time limitations. This proposal is augmented time to obtain early acq images of two LMC remnants and spectra of N49, which had early acq images in Cy. 0. NOTE: SPECTROSCOPY AND IMAGING ORIGINALLY IN THE CYCLE 2 PROPOSAL 4108 HAVE BEEN SPLIT BY STSCI INTO TWO SEPARATE PROPOSALS TO ALLOW FOR SCHEDULING OF CYCLE 2 EARLY ACQ IMAGING ( THIS PROPOSAL ) SINCE CYCLE 2 SPECTROSCOPY DEPENDS ON MEASUREMENT OF EARLY ACQ IMAGING OF OTHER TARGETS FROM EARLIER CYCLES.

Davidsen, Arthur

1992-07-01

381

Supernova Remnants and Nucleosynthesis (fos 30): Augmentation Cycle 2 Observations - Spectroscopy  

NASA Astrophysics Data System (ADS)

Overall program: UV and optical spectra of four supernova remnants (SNRs) will be used to study a number of problems related to abundances, grain destruction, interstellar medium properties and physical conditions in SNR shocks. Representatives of three of the main classes of SNRs (Crab-nebula like, Balmer-line and "normal") will be studied in the LMC, where reasonably low reddening permits UV observations. An oxygen-rich SNR in NGC 4449 will be observed, taking advantage of the small FOS slits to isolate the SNR from surrounding H II emission. Two M33 SNRs that were previously part of this proposal have been dropped due to time limitations. This proposal is augmented time to obtain early acq images of two LMC remnants and spectra of N49, which had early acq images in Cy. 0. NOTE: SPECTROSCOPY AND IMAGING ORIGINALLY IN THIS CYCLE 2 PROPOSAL HAVE BEEN SPLIT BY STSCI INTO TWO SEPARATE PROPOSALS TO ALLOW FOR SCHEDULING OF CYCLE 2 EARLY ACQ IMAGING ( FOR LATER CYCLES ) SINCE CYCLE 2 SPECTROSCOPY DEPENDS ON MEASUREMENT OF EARLY ACQ IMAGING OF OTHER TARGETS FROM EARLIER CYCLES.

Davidsen, Arthur

1992-07-01

382

Fermi-LAT Observations and a Broadband Study of Supernova Remnant CTB 109  

NASA Astrophysics Data System (ADS)

CTB 109 (G109.1-1.0) is a Galactic supernova remnant (SNR) with a hemispherical shell morphology in X-rays and in the radio band. In this work, we report the detection of ?-ray emission coincident with CTB 109, using 37 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 ?-ray emission is produced primarily by leptons accelerated at the SNR forward shock and the other where ?-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 ?-ray flux observed.

Castro, Daniel; Slane, Patrick; Ellison, Donald C.; Patnaude, Daniel J.

2012-09-01

383

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

384

FERMI-LAT AND WMAP OBSERVATIONS OF THE PUPPIS A SUPERNOVA REMNANT  

SciTech Connect

We report the detection of GeV {gamma}-ray emission from the supernova remnant (SNR) Puppis A with the Fermi Gamma-Ray Space Telescope. Puppis A is among the faintest SNRs yet detected at GeV energies, with a luminosity of only 2.7 Multiplication-Sign 10{sup 34} (D/2.2 kpc){sup 2} erg s{sup -1} between 1 and 100 GeV. The {gamma}-ray emission from the remnant is spatially extended, with a morphology matching that of the radio and X-ray emission, and is well described by a simple power law with an index of 2.1. We attempt to model the broadband spectral energy distribution (SED), from radio to {gamma}-rays, using standard nonthermal emission mechanisms. To constrain the relativistic electron population we use 7 years of Wilkinson Microwave Anisotropy Probe data to extend the radio spectrum up to 93 GHz. Both leptonic- and hadronic-dominated models can reproduce the nonthermal SED, requiring a total content of cosmic-ray electrons and protons accelerated in Puppis A of at least W {sub CR} Almost-Equal-To (1-5) Multiplication-Sign 10{sup 49} erg.

Hewitt, J. W. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Grondin, M.-H. [Max-Planck-Institut fuer Kernphysik, D-69029 Heidelberg (Germany); Lemoine-Goumard, M.; Reposeur, T. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan, Universite Bordeaux 1, CNRS/IN2p3, F-33175 Gradignan (France); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Tanaka, T., E-mail: john.w.hewitt@nasa.gov, E-mail: marie-helene.grondin@mpi-hd.mpg.de, E-mail: lemoine@cenbg.in2p3.fr [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)

2012-11-10

385

Spitzer Observations of Dust Destruction in the Puppis A Supernova Remnant  

NASA Technical Reports Server (NTRS)

The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 micrometers shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

Arendt, Richard G.; Dweek, Eli; Blair, William P.; Ghavamian, Parviz; Hwang, Una; Long, Knox X.; Petre, Robert; Rho, Jeonghee; Winkler, P. Frank

2010-01-01

386

SPITZER OBSERVATIONS OF DUST DESTRUCTION IN THE PUPPIS A SUPERNOVA REMNANT  

SciTech Connect

The interaction of the Puppis A supernova remnant (SNR) with a neighboring molecular cloud provides a unique opportunity to measure the amount of grain destruction in an SNR shock. Spitzer Space Telescope MIPS imaging of the entire SNR at 24, 70, and 160 {mu}m shows an extremely good correlation with X-ray emission, indicating that the SNR's IR radiation is dominated by the thermal emission of swept-up interstellar dust, collisionally heated by the hot shocked gas. Spitzer IRS spectral observations targeted both the Bright Eastern Knot (BEK) of the SNR where a small cloud has been engulfed by the supernova blast wave and outlying portions of the associated molecular cloud that are yet to be hit by the shock front. Modeling the spectra from both regions reveals the composition and the grain size distribution of the interstellar dust, both in front of and behind the SNR shock front. The comparison shows that the ubiquitous polycyclic aromatic hydrocarbons of the interstellar medium are destroyed within the BEK, along with nearly 25% of the mass of graphite and silicate dust grains.

Arendt, Richard G. [CRESST, University of Maryland-Baltimore County, Baltimore, MD 21250 (United States); Dwek, Eli [NASA Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Blair, William P.; Hwang, Una [Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Ghavamian, Parviz; Long, Knox S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Petre, Robert [NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Rho, Jeonghee [Spitzer Science Center, MS 220-6, California Institute of Technology, Pasadena, CA 91125 (United States); Winkler, P. Frank, E-mail: Richard.G.Arendt@nasa.go [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

2010-12-10

387

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;