Thermal and Nonthermal X‐Ray Emission from the Forward Shock in Tycho’s Supernova Remnant

Hwang, U.; Decourchelle, A.; Holt, S. S.; Petre, Robert

doi:10.1086/344366

Cited by 159 publications

(203 citation statements)

References 56 publications

Supporting

Mentioning

172

Contrasting

Order By: Relevance

“…This is most clearly evident in the northwest, where nonthermal emission is weak, but clumping is seen throughout the interior, at least in all portions of the SNR that we have observed with Chandra. These fluffy ejecta structures strongly resemble those seen in Tycho's SNR, the other confirmed young Type Ia (Hwang et al 2002). The physical scale is similar, and there is evidence of ejecta extending to the forward shock.…”

Section: Shocked Ejectasupporting

confidence: 63%

ChandraCCD Imagery of the Northeast and Northwest Limbs of SN 1006

Long

Reynolds

Raymond

et al. 2003

ApJ

Self Cite

153

190

View full text Add to dashboard Cite

We present deep images of the SN 1006 remnant (G327.6+14.6) with the ACIS instrument on the Chandra X-Ray Observatory. Two regions have been observed, the synchrotron-dominated northeast limb and the thermally dominated northwest limb, as well as a substantial portion of the interior of the remnant shell. The brightest features in the X-ray images correspond closely to radio features in the northeast and to Balmer-dominated filaments in the northwest. The spectra of the brighter filaments in the northeast are harder, with less prominent line emission than those in the northwest. In addition to highly elongated filaments, both images show enhanced clumps of emission well inside of the shock front that appear to be dominated by emission from oxygen. These probably arise from shock-heated ejecta, based on analysis of their X-ray spectra. We find no firm evidence for a halo of X-ray emission outside the shock to the northeast, as predicted by the Fermi shock-acceleration picture, in which relativistic electrons should be diffusing ahead of the shock. Our limits on upstream emission are less than 1.5% of the postshock levels in regions where the supernova remnant is brightest. This strongly suggests that the bright rims are flattened sheets nearly perpendicular to the plane of the sky and that the magnetic field strength jumps at the shock by a factor significantly larger than 4, as has been proposed if the shock puts significant energy into accelerating nonthermal ions. The spectra obtained of the northwest rim are all dominated by the helium-like ions of O, Ne, Mg, and Si expected from shocks with ionization (n e t) parameters of order 100 cm À3 yr and electron temperatures of 0.5-1 keV, far lower than the postshock ion temperature implied by estimates of the shock speed obtained from the shape of the H line.

show abstract

Section: Shocked Ejectasupporting

confidence: 63%

ChandraCCD Imagery of the Northeast and Northwest Limbs of SN 1006

Long

Reynolds

Raymond

et al. 2003

ApJ

Self Cite

153

190

View full text Add to dashboard Cite

show abstract

“…The filaments in Vela Jr. are rather straight, and their lengths are comparable to the radius of the SNR, which are similar to those in SN 1006 ( Bamba et al 2003b) and Tycho (Hwang et al 2002) and are unlike the clumpy filaments in Cas A (Vink & Laming 2003), RCW 86 (Rho et al 2002), and RX J1713.7À 3946 (Uchiyama et al 2003;Lazendic et al 2004;CassamChenaï et al 2004). The former samples are located in tenuous interstellar space, whereas for the two SNRs in the latter cases, there are some reports about the interaction between shocks and molecular clouds (RCW 86: Y.…”

Section: Interaction With Molecular Clouds?mentioning

confidence: 75%

ChandraObservations of Galactic Supernova Remnant Vela Jr.: A New Sample of Thin Filaments Emitting Synchrotron X‐Rays

Bamba

Yamazaki

Hiraga

2005

ApJ

100

View full text Add to dashboard Cite

The Galactic supernova remnant (SNR) Vela Jr. (RX J0852.0À4622, G266.6-1.2) shows sharp filamentary structures on its northwestern edge in the hard X-ray band. The filaments are very smooth and located on the extreme outside edge of the remnant. We measured the averaged scale width of the filaments (w u and w d ) with excellent spatial resolution with Chandra, and they are on the order of the size of the point-spread function of Chandra on the upstream side and 49B5 (36B0-88B8) on the downstream side. The spectra of the filaments are very hard and have no linelike structure; they were well reproduced with an absorbed power-law model with À ¼ 2:67 (2.55-2.77) or a SRCUT model with roll ¼ 4:3 (3:4 5:3) ; 10 16 Hz under the assumption of p ¼ 0:3. These results imply that the hard X-rays are synchrotron radiation emitted by accelerated electrons, as mentioned previously. Using a correlation between the function B roll /w 2 d and the SNR age, we estimated the distance and the age of Vela Jr.: the estimated distance and age are 0.33 (0.26-0.50) kpc and 660 (420-1400) yr, respectively. These results are consistent with previous reports, implying that the B-age relation may be a useful tool for estimating the distance and the age of synchrotron X-ray-emitting SNRs. Subject headingg s: acceleration of particles -ISM: individual (G266.6-1.2, RX J0852.0À4622) -supernova remnants -X-rays: ISM

show abstract

“…Chandra high-angular resolution X-ray observations of young supernova remnants (SNR) such as Cassiopeia A, Kepler or Tycho, have detected very thin X-ray filaments, which are probably associated with the supernova (SN) forward shock expanding into the interstellar medium (ISM) (Gotthelf et al 2001;Hwang et al 2002;Rho et al 2002;Uchiyama et al 2003;Cassam-Chenaï et al 2004;Bamba et al 2005a,b;Cassam-Chenaï et al 2007). The physical properties of these filaments were reviewed by Vink & Laming (2003), Vink (2004), Weisskopf & Hughes (2006), Ballet (2006), Parizot et al (2006), Bamba et al (2006), and Berezhko (2008).…”

Section: Introductionmentioning

confidence: 99%

Postshock turbulence and diffusive shock acceleration in young supernova remnants

Marcowith¹,

Casse²

2010

A&A

View full text Add to dashboard Cite

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 regimes of the streaming instability. We attempt to understand more clearly of the diffusive shock acceleration (DSA) efficiency by considering various relaxation processes of the magnetic fluctuations in the downstream medium. Multiwavelength radiative signatures originating in the SNR shock wave are used to test various downstream turbulence relaxation models. Methods. Analytical and numerical calculations that couple stochastic differential equation schemes with 1D spherical magnetohydrodynamics simulations are used to investigate, in the context of test particles, turbulence evolution in both the forshock and post-shock regions. Stochastic second-order Fermi acceleration induced by resonant modes, magnetic field relaxation and amplification, and turbulence compression at the shock front are considered to model the multiwavelength filaments produced in SNRs. The γ-ray emission is also considered in terms of inverse Compton mechanism. Results. We confirm the result of Parizot and collaborators that the maximum CR energies should not go well beyond PeV energies in young SNRs where X-ray filaments are observed. To reproduce observational data, we derive an upper limit to the magnetic field amplitude and so ensure that stochastic particle reacceleration remains inefficient. Considering various magnetic relaxation processes, we then infer two necessary conditions to achieve efficient acceleration and X-ray filaments in SNRs: (1) the turbulence must fulfil the inequality 2 − β − δ d ≥ 0; where β is the turbulence spectral index and δ d is the relaxation length energy power-law index; (2) the typical relaxation length must be of the order the X-ray rim size. We find that Alvénic/fast magnetosonic mode damping fulfils all conditions; while non-linear Kolmogorov damping does not. By confronting previous relaxation processes with observational data, we deducte that among our SNR sample, data for the older ones (SN1006 and G347.3-0.5) does not comply with all conditions, which means that their X-ray filaments are probably controlled by radiative losses. The younger SNRs, Cassiopeia A, Tycho, and Kepler pass all tests and we infer that the downstream magnetic field amplitude is in the range of 200−300 μGauss.

show abstract

Thermal and Nonthermal X‐Ray Emission from the Forward Shock in Tycho’s Supernova Remnant

Cited by 159 publications

References 56 publications

ChandraCCD Imagery of the Northeast and Northwest Limbs of SN 1006

ChandraCCD Imagery of the Northeast and Northwest Limbs of SN 1006

ChandraObservations of Galactic Supernova Remnant Vela Jr.: A New Sample of Thin Filaments Emitting Synchrotron X‐Rays

Postshock turbulence and diffusive shock acceleration in young supernova remnants

Contact Info

Product

Resources

About