The shell-type supernova remnant (SNR) RCW 86, possibly associated with the historical supernova SN 185, with its relatively large size (about 40' in diameter) and the presence of non-thermal X-rays is a promising target for gamma-ray observations. The high sensitivity, good angular resolution of a few arc minutes and the large field of view of the High Energy Stereoscopic System (H.E.S.S.) make it ideally suited for the study of the gamma-ray morphology of such extended sources. H.E.S.S. observations have indeed led to the discovery of the SNR RCW 86 in very high energy (VHE; E > 100 GeV) gamma-rays. With 31 hours of observation time, the source is detected with a statistical significance of 8.5 sigma and is significantly more extended than the H.E.S.S. point spread function. Morphological studies have been performed and show that the gamma-ray flux does not correlate perfectly with the X-ray emission. The flux from the remnant is ~10% of the flux from the Crab nebula, with a similar photon index of about 2.5. Possible origins of the very high energy gamma-ray emission, via either Inverse Compton scattering by electrons or the decay of neutral pions produced by proton interactions, are discussed on the basis of spectral features obtained both in the X-ray and gamma-ray regimes.
The results of the 2D modelling of Supernova remnant (SNR) RCW86 are given. Models of this remnant, which for the first time interpret the anisotropy of surface brightness as a result of the evolution of adiabatic SNR in the interstellar medium with a large-scale gradient of density, are considered. Estimations on the basic characteristics of RCW86 and the surrounding medium which follow from these models are found. It is shown that the observed surface brightness distribution of RCW86 may be obtaned in the both proposed up till now models with different initial assumptions: one about a Supern…
We report results from high resolution optical spectroscopy of three non-radiative galactic supernova remnants, RCW 86, Kepler's supernova remnant and SN 1006. We have measured the narrow component H-alpha line widths in Balmer-dominated filaments in RCW 86 and SN 1006, as well as the narrow component width in a Balmer-dominated knot in Kepler's SNR. The narrow component line widths measured in RCW 86 and Kepler's SNR show FWHM of 30-40 km/s, similar to what has been seen in other Balmer-dominated remnants. Of the remnants in our sample, SN 1006 is the fastest shock (~3000 km/s). The narrow co…
We report on the discovery of an unresolved X-ray source inside the supernova remnant G315.4-2.3 (RCW 86). The source is located 7' to the Southwest of the geometrical centre and may be close to the actual explosion centre of the supernova, which makes this a candidate for the stellar remnant associated with RCW 86. However, the presence of a possible optical counterpart with $V \sim 14$ at 3" from the X-ray position and evidence for long term variability means that the source is probably an active star. A better X-ray position and better X-ray spectroscopy along with an identification of the …
The discovery of the 6.67 hr periodicity in the X-ray source 1E 161348-5055 associated with the supernova remnant RCW 103 has raised interesting suggestions about the nature of the X-ray source. Here we argue that in either accreting neutron star or magnetar model, a supernova fallback disk may be a critical ingredient in theoretical interpretations of 1E 161348-5055. We further emphasize the effect of fallback disks on the evolution of young compact objects in various ways, and suggest that even SS 433 could also be powered by fallback disk accretion process.
I discuss the nature of the compact X-ray source in the center of the supernova remnant RCW 103. Several models, based on the accretion onto a compact object are analyzed. I show that it is more likely that the central X-ray source is an accreting neutron star than an accreting black hole. I also argue that models of a disrupted binary system consisting of an old accreting neutron star and a new one observed as a 69-ms pulsar are most favored.
The shell-type supernova remnant (SNR) RCW 86 - possibly associated with the historical supernova SN 185 - was observed during the past three years with the High Energy Stereoscopic System (H.E.S.S.), an array of four atmospheric-Cherenkov telescopes located in Namibia. The multi-wavelength properties of RCW 86, e.g. weak radio emission and North-East X-ray emission almost entirely consisting of synchroton radiation, resemble those of two very-high energy (VHE; > 100 GeV) gamma-ray emitting SNRs RX J1713.7-3946 and RX J0852-4622. The H.E.S.S. observations reveal a new extended source of VHE ga…
We present an analysis of ASCA X-ray data of SNR RCW 86. There appears to be a remarkable spectral variation over the remnant, indicating temperatures varying from 0.8 keV to > 3 keV. We have fitted these spectra with non-equilibrium ionization models and found that all regions are best fitted by emission from a hot plasma underabundant in metals (<0.25 solar), but in some cases fluorescent emission indicates overabundances of Ar and Fe. The ionization stage of the metals appears to be far from equilibrium, at some spots as low as log(n_e t) 15.3 (SI units). We discuss the physical reality of …
We suggest that the unique X-ray source 1E161348-5055 at the centre of the supernova remnant RCW 103 consists of a neutron star in close orbit with a low mass main sequence star. The time signature of 6.67 hr is interpreted as the neutron star's spin period. This requires the neutron star to be endowed with a high surface magnetic field of~10^15 G. Magnetic or/and material (propeller) torques are able to spin rapidly the young neutron star down to an asymptotic, equilibrium spin period in close synchronism with the orbital period, similarly to what happens in the Polar Cataclysmic Variables. 1…
In this poster I discuss the nature of the compact X-ray source in the center of the supernova remnant RCW 103. Several models, based on the accretion onto a compact object such as a neutron star or a black hole (isolated or binary), are analyzed. I show that it is more likely that the central X-ray source is an accreting neutron star than an accreting black hole. I also argue that models of a disrupted binary system consisting of an old accreting neutron star and a new one observed as a 69-ms X-ray and radio pulsar are most favored.
Supernova remnants may exhibit both thermal and nonthermal X-ray emission. Such remnants can be distinguished by the weakness of their X-ray lines, because of the presence of a strong nonthermal X-ray continuum. RCW 86 is a remnant with weak lines, resulting in low and peculiar abundances when thermal models alone are used to interpret its X-ray spectrum. This indicates the presence of a strong nonthermal synchrotron continuum. We analyze ASCA X-ray spectra of RCW 86 with the help of both nonequilibrium ionization thermal models and nonthermal synchrotron models. A two-temperature thermal mode…
The association between the Pencil nebula (RCW 37, NGC 2736), the Vela X-ray fragment D/D' and the recently discovered new X-ray supernova remnant (RX J0852.0-4622) in Vela is investigated. Recently published Chandra images of D/D' are compared with optical images of RCW 37 and confirm the close association of the two objects. New optical line profiles of RCW 37 from an extended slit position passing through this unusual optical nebula are presented. They reveal a partial velocity ellipse with expansion velocities of around 120 km/s. Various scenarios for the origin of the nebula are considere…
A new ASCA observation of 1E 161348-5055, the central compact X-ray source in the supernova remnant RCW 103, reveals an order-of-magnitude decrease in its 3 - 10 keV flux since the previous ASCA measurement four years earlier. This result is hard to reconcile with suggestions that the bulk of the emission is simple quasi-blackbody, cooling radiation from an isolated neutron star. Furthermore, archived EINSTEIN and ROSAT datasets spanning 18 years confirm that this source manifests long-term variability, to a lesser degree. This provides a natural explanation for difficulties encountered in rep…
We present an analysis of the X-ray emission of the supernova remnant MSH14-63, which was partially covered by four observations with XMM-Newton. The detection of Fe K emission at 6.4 keV, and the lack of spatial correlation between hard X-ray and radio emission is evidence against a dominant X-ray synchrotron component. We argue that the hard X-ray continuum is best explained by non-thermal bremsstrahlung from a supra-thermal tail to an otherwise cool electron gas. The existence of low electron temperatures, required to explain the absence of line emission, is supported by low temperatures fo…
We report the detection of the radio pulsar counterpart to the 69 ms X-ray pulsar discovered near the supernova remnant RCW 103 (G332.4-0.4). Our detection confirms that the pulsations arise from a rotation-powered neutron star, which we name PSR J1617-5055. The observed barycentric period derivative confirms that the pulsar has a characteristic age of only 8 kyr, the sixth smallest of all known pulsars. The unusual apparent youth of the pulsar and its proximity to a young remnant requires that an association be considered. Although the respective ages and distances are consistent within subst…
We present an observational and theoretical study of the optical emission from nonradiative shocks in three supernova remnants: the Cygnus Loop, RCW 86 and Tycho. The spectra of these shocks are dominated by collisionally excited hydrogen Balmer lines which have both a broad component caused by proton-neutral charge exchange and a narrow component caused by excitation of cold neutrals entering the shock. In each remnant we have obtained the broad to narrow flux ratios of the Halpha and Hbeta lines and measured the Halpha broad component width. A new numerical shock code computes the broad and …
We present a spectral analysis of the Northern and Southwestern rim of the RCW86 X-ray shell, pointing out the remarkable differences between these two parts of the same object. In the North, a single temperature Non Equilibrium of Ionization emission model describes the data well, and the derived abundances of O, Ne, Mg, Si, S, Ar and Fe are in agreement with expected metal depletion behind a fast shock moving in the interstellar medium. If the initial explosion energy was $\sim 10^{51}$ erg, the derived distance and age are $1.18^{+0.17}_{-0.16}$ kpc and $1630^{+440}_{-360}$ yr, fully consis…
Recent observations of the compact source embedded within the supernova remnant RCW 103 rekindle interest in the origin of this object's emission. We contrast several models in which neutron-star cooling powers RCW 103. Specifically, either the presence of an accreted envelope or a sufficiently intense magnetic field can account for the X-ray emission from this object.
We report the discovery of Balmer-dominated filaments along almost the complete periphery of the supernova remnant RCW 86 (also known as G 315.2-2.3 or MSH 14-63). Using the UM/CTIO Curtis Schmidt telescope, we obtained deep CCD images in the emission of Halpha and [S II], together with continuum images to remove stellar confusion. After continuum subtraction, we discovered a network of Halpha filaments reaching almost completely around the remnant. Most of the newly identified filaments show no corresponding [S II] emission, indicating that they belong to the peculiar ''Balmer-dominated'' cla…
We consider the nature of the elusive neutron star candidate 1E~161348-5055 using X-ray observations obtained with the ASCA Observatory. The compact X-ray source is centered on the shell-type Galactic supernova remnant RCW103 and has been interpreted as a cooling neutron star associated with the remnant. The X-ray spectrum of the remnant shell can be characterized by a non-equilibrium ionization (NEI) thermal model for a shocked plasma of temperature kT ~ 0.3 keV. The spectrum falls off rapidly above 3 keV to reveal a point source in the spectrally-resolved images, at the location of 1E~161348…
We report here X-ray imaging spectroscopy observations of the northeastern shell of the supernova remnant RCW 86 with Chandra and XMM-Newton. Along this part of the shell the dominant X-ray radiation mechanism changes from thermal to synchrotron emission. We argue that both the presence of X-ray synchrotron radiation and the width of the synchrotron emitting region suggest a locally higher shock velocity of V_s = 2700 km/s and a magnetic field of B = 24+/-5 microGauss. Moreover, we also show that a simple power law cosmic ray electron spectrum with an exponential cut-off cannot explain the bro…
We present an analysis of the X-ray emission of the supernova remnant MSH14-63, which was partially covered by three observations with XMM-Newton. The detection of Fe K emission at 6.4 keV, and the lack of spatial correlation between hard X-ray and radio emission is evidence against a dominant X-ray synchrotron component. We argue that the hard X-ray continuum is best explained by non-thermal bremsstrahlung from a supra-thermal tail to an otherwise cool electron gas. The existence of low electron temperatures is supported by low temperatures found in other parts of the remnant, which are as lo…
I discuss the nature of the compact X-ray source inside the supernova remnant RCW 103. Several models, based on the accretion onto a compact object such as a neutron star or a black hole (isolated or binary), are analyzed. I show that it is more likely that the X-ray source is an accreting neutron star than an accreting black hole. I also argue that models of a binary system with an old accreting neutron star are most favored.
We report on the detection of HCO+ and 12CO emission in the rotational transition J=1-0 in the vicinity of the shock front at the southern border of the supernova remnant RCW 103, where previous infrared observations suggest an interaction with a molecular cloud. The observations were carried out with the Australian Millimeter Radiotelescope at Mopra. We observed a depletion of HCO+ behind the supernova shock front. In addition, we studied the interstellar medium over an extended region towards RCW 103 based on archival 21 cm HI line observations from the Australia Telescope Compact Array (ATC…
Recent studies of narrow, X-ray synchrotron radiating filaments surrounding young supernova remnants indicate that magnetic fields strengths are relatively high, B ~ 0.1 mG, or even higher, and that diffusion is close to the Bohm limit. I illustrate this using Cas A as an example. Also older remnants such as RCW 86 appear to emit X-ray synchrotron radiation, but the emission is more diffuse, and not always confined to a region close to the shock front. I argue that for RCW 86 the magnetic field is likely to be low (B ~ 17 microGauss), and at the location where the shell emits X-ray synchrotron…
We report the results of a search for a point X-ray source (stellar remnant) in the southwest protrusion of the supernova remnant G 315.4-2.30 (MSH 14-63, RCW 86) using the archival data of the Chandra X-ray Observatory. The search was motivated by a hypothesis that G 315.4-2.30 is the result of an off-centered cavity supernova explosion of a moving massive star, which ended its evolution just near the edge of the main-sequence wind-driven bubble. This hypothesis implies that the southwest protrusion in G 315.4-2.30 is the remainder of a pre-existing bow shock-like structure created by the int…
We report the ASCA (Advanced Satellite for Cosmology and Astrophysics) results of RCW 86, a shell-like supernova remnant (SNR). The bright region in the X-ray band traces the radio clumpy shell, although details of the structure are different. The X-ray spectrum from each part of the shell can not be fitted to a thin thermal plasma model, but requires, at least three components: a low temperature plasma of 0.3 keV, high temperature plasma of > several keV, and a power-law component with a photon index = 3. The abundances of O, Ne, Mg and Si are significantly higher than that of Fe, indicating …
G315.4-2.3 is an extended shell supernova remnant (SNR) with some characteristics of evolutionarily young remnants and some of older ones. To further elucidate some of its characteristics, we present imaging and polarimetry of this SNR at a frequency of 1.34 GHz with a resolution of 8 arcsec made with the Australia Telescope Compact Array. The indicators of youth are: Morphologically, the radio emission arises in a smooth shell without the fine scale filaments seen in the optical. Many of the optical filaments are Balmer dominated. Where measurable, the orientation of the magnetic field appear…
We discuss a concept of off-centred cavity supernova explosion as applied to neutron star/supernova remnant associations and show how this concept could be used to preclude the anti-humane decapitating the Duck (G5.4-1.2 + G5.27-0.9) and dismembering the Swan (Cygnus Loop), as well as to search for a stellar remnant associated with the supernova remnant RCW86.
We report on our search for the optical counterparts of the Southern Hemisphere anomalous X-ray pulsar 1E1048.1-5937 and the radio-quiet neutron stars in supernova remnants Puppis A, RCW 103, and PKS 1209-52. The observations were carried out with the new MIT/CfA MagIC camera on the Magellan-I 6.5 m telescope in Chile. We present deep multiband optical images of the X-ray error circles for each of these targets and discuss the resulting candidates and limits.
The paradigm that young neutron stars (NSs) evolve as rapidly rotating Crab-like pulsars requires re-examination. Evidence is accumulating that, in fact, many young NS are slowly rotating (P ~ 10-s) X-ray pulsars, lacking in detectable radio emission. We present new results on three radio-quiet NS candidates associated with supernova remnants, which suggests that alternative evolutionary-paths exist for young pulsars. These include the 12-s pulsator in Kes 73, the 7-s pulsar near Kes 75, and the enigmatic X-ray source in RCW 103. We postulate that such objects account for the apparent paucity …
We report on our search for the optical/infrared counterparts to the central compact objects in four young supernova remnants: Pup A, PKS 1209-52, RCW 103, and Cas A. The X-ray point sources in these supernova remnants are excellent targets for probing the existence of supernova fallback disks, since irradiation of a disk by a central X-ray source should lead to an infrared excess. We used ground-based optical and near-infrared imaging and Spitzer Space Telescope mid-infrared imaging to search for optical/infrared counterparts at the X-ray point source positions measured by the Chandra X-Ray O…
The development of observational techniques has inriched our knowledge of supernova remnants. In this paper, we review the main progresses in the last decade, including new discoveries of supernova remnants and the associated (rare type of) pulsars, nucleosynthesis, the interaction between supernova remnants and molecular clouds, dust in the supernova remnants, shock physics, and cosmic ray accelerations.
Supernova remnants are usually analysed in the light of hydrodynamical models of the interaction of supernova ejecta with either a constant density ambient medium or a circumstellar medium produced by a constant presupernova wind. However, the ejection of energetic wind during the presupernova phase changes the ambient medium structure and, consequently, the early supernova remnant evolution. We have analysed the evolution of young remnants of type Ia supernovae, focusing on the imprint of the presupernova wind history on the supernova remnant structure and on the influence of the explosion me…
Using the Australia Telescope Compact Array, we have carried out a survey of the HI emission in the direction of the ``barrel-shaped'' supernova remnant (SNR) G320.4-1.2 (MSH 15-52) and its associated young pulsar B1509-58. The angular resolution of the data is 4.0x2.7 arcmin, and the rms noise of the order of 30 mJy/beam (~0.5 K). The HI observations indicate that the N-NW radio limb has encountered a dense HI filament (density ~12 cm^-3) at the same LSR velocity than that of the SNR (V_LSR ~ -68 km/s). This HI concentration would be responsible for the flattened shape of the NW lobe of G320.…
X-ray images of some young supernova remnants show bright point sources which have not been detected in radio, optical and gamma-ray bands. Despite the similarity of the X-ray spectra of these objects, they show a variety of temporal properties. Most likely, they are neutron stars whose properties (spin periods? magnetic fields? environments?) are different from those of radio and/or gamma-ray pulsars. We present an overview of observational results on several objects of this class -- the central sources of Cassiopeia A, RX J0852-4622, RCW 103, Puppis A, and PKS 1209-51/52 -- with emphasis on …
We have used archival ROSAT data to present X-ray images of thirty-one supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). We have classified these remnants according to their X-ray morphologies, into the categories of Shell-Type, Diffuse Face, Centrally Brightened, Point-Source Dominated, and Irregular. We suggest possible causes of the X-ray emission for each category, and for individual features of some of the SNRs.
October 2004 marks the 400th anniversary of the sighting of SN 1604, now marked by the presence of an expanding nebulosity known as Kepler's supernova remnant. Of the small number of remnants of historical supernovae, Kepler's remnant remains the most enigmatic. The supernova type, and hence the type of star that exploded, is still a matter of debate, and even the distance to the remnant is uncertain by more than a factor of two. As new and improved multiwavength observations become available, and as the time baseline of observations gets longer, Kepler's supernova remnant is slowly revealing …
The newly operational X-ray satellite Suzaku observed the southwestern quadrant of the supernova remnant (SNR) RCW 86 in February 2006 to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirm the existence of the line, localizing it for the first time; most of the line emission is adjacent and interior to the forward shock and not at the locus of the continuum hard emission. We also report the first detection of a 7.1 keV line that we interpret as the K-beta emission from low-ionization iron. The Fe-K l…
We present the results of three observations of shell-type supernova remnants observed by BeppoSAX. Two of the remnants (N132D and Cas A) are oxygen rich supernova remnants. They were observed during the PV phase. SN1006 was observed during A01. For SN1006 we present preliminary results on the abundance measurements based on the emission from the center of the remnant.
Massive clusters are more often found in actively star forming galaxies than in quiescent ones, similar to the Milky Way. We have carried out an extensive survey of obscured Milky Way clusters to determine whether our Galaxy is still forming such objects. Near-infrared spectral classification of some probable cluster members was used to derive the distances to the cluster candidates. Isochrone analysis of deep near-infrared color-magnitude diagrams allowed us to obtain age and mass estimates. We report the physical parameters of three cluster candidates: RCW87 is approx. 25 Myr old, located at…
In this paper we discuss possible ultra high energy ($\ge$ TeV) neutrino emission from Supernova Remnants (SNRs), specifically the hadronic gamma ray production models. Recent very high energy (VHE) $γ$ ray observation from SNRs is the main motivation behind this study.
Supernovae descendent from massive stars explode in media that have been modified by their progenitors' mass loss and UV radiation. The supernova ejecta will first interact with the circumstellar material shed by the progenitors at late evolutionary stages, and then interact with the interstellar material. Circumstellar nebulae in supernova remnants can be diagnosed by their small expansion velocities and high [N II]/H$α$ ratios. The presence of circumstellar nebulae appears ubiquitous among known young supernova remnants. These nebulae can be compared to those around evolved massive stars to …
The interaction between the ejecta from Supernova 1987A and surrounding material is producing steadily brightening radio and X-ray emission. The new-born supernova remnant has been significantly decelerated by this interaction, while its morphology reflects the axisymmetric nature of the progenitor wind.
I briefly summarize some facts and ideas concerning the presence of neutron stars in Supernova remnants. While sources similar to the Crab Nebula require the presence of a central energetic object, shell-type remnants such as Cas A are compatible with the presence of neutron stars releasing a weak relativistic wind.
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 ~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 SNR (in particular from RX J1713.7-3946) targets of future underwater neutrino telescopes.
We propose that some of the unidentified Galactic plane (-10 degrees < b < 10 degrees) sources listed in the first EGRET catalog (Fichtel et al. 1994) are associated with nearby supernova remnants. The probability that the association of strong EGRET sources with supernova remnants is due to chance alignment is found to be < 1/2200. Three of the most convincing associations are radio-bright, nearby shell remnants and a fourth is associated with a plerion. We examine possible gamma-ray production mechanisms and conclude that pion production and decay from high-energy protons interacting with th…
The launch of Chandra and XMM-Newton has led to important new findings concerning the X-ray emission from supernova remnants. These findings are a result of the high spatial resolution with which imaging spectroscopy is now possible, but also some useful results have come out of the grating spectrometers of both X-ray observatories, despite the extended nature of supernova remnants. The findings discussed here are the evidence for slow equilibration of electron and ion temperatures near fast supernova remnant shocks, the magnetic field amplification near remnant shocks due to cosmic ray accele…
We have carried out a study of the neutral hydrogen in the direction of the X-ray source 1E 161348-5055, a compact central object (CCO) located in the interior of the supernova remnant (SNR) RCW 103. The HI 21 cm line observations were carried out using the Australia Telescope Compact Array, complemented with single dish data from the Parkes radio telescope to recover information at all spatial scales. We derive a distance to RCW 103 of 3.3 kpc, in agreement with previous distance measurements. We have also detected a small hole in the HI emission which is positionally and kinematically coinci…
A review of the main issues in the field of particle acceleration in Supernova Remnants is provided in the context of future X-ray observations with Simbol-X. After a summary of the nonthermal acceleration mechanisms at work, I briefly review the observations of supernova remnants in hard X-rays and in gamma rays. Open issues are discussed in this framework.
After reviewing recent work on the dynamics of young supernova remnants (YSNRs) and discussing how YSNRs can be used as physics laboratories, I discuss several challenges: Where are the very young SNRs in the Galaxy? Can very young SNRs produce gamma ray bursts? The Connections Challenge: Can one infer the nature of the supernova and its progenitor star from observations of the YSNR?
This brief review of recent X-ray observations of young supernova remnants highlights results obtained by the Chandra and XMM Newton Observatories since their launch last year. Their impressive capabilities are illustrated by results for spectral imaging, and for spatially resolved spectroscopy that isolates emission from individual ejecta knots and from the forward shock. I also review X-ray dynamical studies of supernova remnants, which should undergo significant advances during this new era.
Radio images of supernova remnants in the framework of diffusion model are discussed. The distribution profiles of synchrotron radiation intensity for spherical injection source of relativistic electrons are reduced at different frequencies. An explanation of the observational data obtained on UTR-2, according to which the size of the supernova remnant at decametric waves is larger than the remnant size at high frequencies, is given.
There are a half-dozen or so young supernova remnants in the Magellanic Clouds that display one or more of the following characteristics: high velocity (>1000 km/s) emission, enhanced metallicity, or a rapidly rotating pulsar. I summarize the current state of knowledge of these remnants and present some recent results mostly from the new X-ray astronomy satellites.
We have obtained high resolution Ca II and Na I absorption line spectra toward 68 OB stars in the direction of the Vela Supernova Remnant. The stars lie at distances of 190 -- 2800 pc as determined by Hipparcos and spectroscopic parallax estimations. The presence of high velocity absorption attributable to the remnant along some of the sight lines constrains the remnant distance to 250+/-30 pc. This distance is consistent with several recent investigations that suggest that the canonical remnant distance of 500 pc is too large.
The successful theoretical supernova explosion models should be able to explain any features of the emission from supernovae at any evolutionary stage. We check several models from two different points of view. With the multi-frequency radiation hydro code STELLA we calculate gamma-ray, bolometric and broad-band UBVI light curves. Then we use the same models to calculate the emission from young supernova remnants. Here we present new plots for gamma-ray luminosity from several SN Ia models and recomputations of bolometric and UBVRI light curves of model 13C for SN 1993J.
Supernova remnants may exhibit both thermal and nonthermal X-ray emission. We present Chandra observations of RCW 86. Striking differences in the morphology of X-rays below 1 keV and above 2 keV point to a different physical origin. Hard X-ray emission is correlated fairly well with the edges of regions of radio emission, suggesting that these are the locations of shock waves at which both short-lived X-ray emitting electrons, and longer-lived radio-emitting electrons, are accelerated. Soft X-rays are spatially well-correlated with optical emission from nonradiative shocks, which are almost ce…
We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single degenerate scenario predict substantial outflows during the presupernova evolution. Expanding on previous work, we estimate the imprint of these outflows on the structure of the circumstellar medium at the time of the supernova explosion, and the effect that this modified circumstellar medium has on the evolution of the ensuing supernova remnant. We compare our simulations with…
We have carried out a sensitive search for young pulsars associated with supernova remnants using the 76-m Lovell radio telescope at Jodrell Bank. The observations were made at 606 MHz using a system with a bandwidth of 8 MHz and a set noise temperature on cold sky of about 50 K. The survey targeted 33 remnants in the northern hemisphere and achieved a nominal sensitivity of ~1 mJy in most cases. Two pulsars were discovered in the course of this survey and the known pulsar PSR B1952+29 was detected. The new pulsars, J0215+6218 and J1957+2831, were found during searches of the supernova remnant…
