Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

Vasisht, Gautam; Aoki, Takashi; Dotani, Tadayasu; Kulkarni, S. R.; Nagase, F.

doi:10.1086/309854

Cited by 44 publications

(40 citation statements)

References 18 publications

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“…The derived age (a few thousand years) and the presence of a central X-ray source makes 3C 397 similar to the young SNRs G11.2È0.3 (Vasisht et al 1996), Kes 73 , and RCW 103 (Petre & Gotthelf 1998). G11.2[0.3 harbors a hard X-ray plerion powered by a fast millisecond pulsar (Torii et al 1997).…”

Section: Discussionmentioning

confidence: 64%

A Broadband X‐Ray Study of Supernova Remnant 3C 397

Safi‐Harb

Petre

Arnaud

et al. 2000

ApJ

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We present a broadband imaging and spectral study of the radio-bright supernova remnant (SNR) 3C 397 with ROSAT , ASCA, and RXT E. A bright X-ray spot seen in the HRI image hints at the presence of a pulsar-powered component and gives this SNR a composite X-ray morphology. Combined ROSAT and ASCA imaging shows that the remnant is highly asymmetric, with its X-ray emission peaking at the western lobe. The hard-band images obtained with the ASCA Gas Imaging Spectrometer show that much of the hard X-ray emission arises from the western lobe, associated with the SNR shell, with little hard X-ray emission associated with the central hot spot. The spectrum from 3C 397 is heavily absorbed and dominated by thermal emission with emission lines evident from Mg, Si, S, Ar and Fe. Single-component models fail to describe the X-ray spectrum, and at least two components are required : a soft component characterized by a low temperature and a large ionization timescale, and a hard component required to account for the Fe-K emission line and characterized by a much lower ionization timescale. We use a set of nonequilibrium ionization (NEI) models (Borkowski et al., in preparation), and Ðnd that the Ðtted parameters are robust. The temperatures from the soft and hard components are D0.2 keV and D1.6 keV respectively. The corresponding ionization timescales being the pren 0 t (n 0 shock hydrogen density) are D6 ] 1012 cm~3 s and D6 ] 1010 cm~3 s, respectively. The large of n 0 t the soft component suggests it is approaching ionization equilibrium ; thus it can be Ðt equally well with a collisional equilibrium ionization model. The spectrum obtained with the Proportional Counter Array (PCA) of RXT E is contaminated by emission from the Galactic ridge, with only D15% of the count rate originating from 3C 397 in the 5È15 keV range. The PCA spectrum allowed us to conÐrm the thermal nature of the hard X-ray emission. A third component originating from a pulsar-driven component is possible, but the contamination of the source signal by the Galactic ridge did not allow us to determine its parameters or Ðnd pulsations from any hidden pulsar. We discuss the X-ray spectrum in the light of two scenarios : a young ejecta-dominated remnant of a core-collapse SN, and a middle-aged SNR expanding in a dense ISM. In the Ðrst scenario, the hot component arises from the SNR shell, and the soft component from an ejecta-dominated component. 3C 397 would be a young SNR (a few thousand years old), but intermediate in dynamical age between the young historical shells (like Tycho or Kepler), and those that are well into the Sedov phase of evolution (like Vela). In the second scenario, the soft component represents the blast wave propagating in a dense medium, and the hard component is associated with hot gas encountering a fast shock, or arising from thermal conduction. In this latter scenario, the SNR would be Dtwice as old, and transitioning into the radiative phase. The current picture we present in this paper is marginally consistent with thi...

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Section: Discussionmentioning

confidence: 64%

A Broadband X‐Ray Study of Supernova Remnant 3C 397

Safi‐Harb

Petre

Arnaud

et al. 2000

ApJ

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“…The PWN and 65-ms period pulsar associated with G11.2−0.3 were discovered using ASCA observations (Vasisht et al 1996;Torii et al 1997), and Kaspi et al (2001) showed that the pulsar is only 8 from the geometric center of the SNR. Borkowski et al (2016) used multiple epochs of Chandra observations to measure a shell expansion rate that implied an age of 1400-2400 years, making G11.2−0.3 one of the youngest identified CC SNRs in the Milky Way.…”

Section: Properties Of the Snrsmentioning

confidence: 99%

Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

Holland-Ashford

Lopez

Auchettl

et al. 2017

ApJ

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Supernova explosions are inherently asymmetric and can accelerate new-born neutron stars (NSs) to hundreds of km s −1 . Two prevailing theories to explain NS kicks are ejecta asymmetries (e.g., conservation of momentum between NS and ejecta) and anisotropic neutrino emission. Observations of supernova remnants (SNRs) can give us insights into the mechanism that generates these NS kicks. In this paper, we investigate the relationship between NS kick velocities and the X-ray morphologies of 18 SNRs observed with the Chandra X-ray Observatory and the Röntgen Satellite (ROSAT). We measure SNR asymmetries using the power-ratio method (a multipole expansion technique), focusing on the dipole, quadrupole, and octupole power-ratios. Our results show no correlation between the magnitude of the power-ratios and NS kick velocities, but we find that for Cas A and G292.0+1.8, whose emission traces the ejecta distribution, their NSs are preferentially moving opposite to the bulk of the X-ray emission. In addition, we find a similar result for PKS 1209-51, CTB 109, and Puppis A; however their emission is dominated by circumstellar/interstellar material, so their asymmetries may not reflect their ejecta distributions. Our results are consistent with the theory that NS kicks are a consequence of ejecta asymmetries as opposed to anisotropic neutrino emission. In the future, additional observations to measure NS proper motions within ejecta-dominated SNRs are necessary to constrain robustly the NS kick mechanism.

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“…The first hints of a central plerionic component came from high-frequency, single-dish radio measurements that suggested a central flattening of the radio spectrum (Morsi & Reich 1987). ASCA observations first clearly demonstrated that there was a central, nonthermal X-ray source (Vasisht et al 1996). This component was resolved by Chandra, the image of which has been presented in Paper I.…”

Section: Introductionmentioning

confidence: 98%

The Pulsar Wind Nebula in G11.2−0.3

Roberts

Tam

Kaspi

et al. 2003

ApJ

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We present an X-ray and radio study of the wind nebula surrounding the central pulsar PSR J1811À1925 in the supernova remnant G11.2À0.3. Using high-resolution data obtained with the Chandra X-Ray Observatory and with the VLA radio telescope, we show the X-ray and radio emission is asymmetric around the pulsar, despite the latter's central position in the very circular shell. The new X-ray data allow us to separate the synchrotron emission of the pulsar wind nebula from the surrounding thermal emission and that from the pulsar itself. On the basis of X-ray data from two epochs, we observe temporal variation of the location of X-ray hot spots near the pulsar, indicating relativistic motion. We compare thermal emission observed within the shell, which may be associated with the forward shock of the pulsar wind nebula, to thermal emission from a nearby portion of the remnant shell, the temperature of which implies an expansion velocity consistent with the identification of the remnant with the historical event of 386 A.D. The measured X-ray and radio spectral indices of the nebula synchrotron emission are found to be consistent with a single synchrotron cooling break. The magnetic field implied by the break frequency is anomalously large, given the apparent size and age of the nebula, if a spherical morphology is assumed but is consistent with a bipolar morphology.

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Detection of a Hard X-Ray Plerion in the Candidate Historical Remnant G11.2−0.3

Cited by 44 publications

References 18 publications

A Broadband X‐Ray Study of Supernova Remnant 3C 397

A Broadband X‐Ray Study of Supernova Remnant 3C 397

Comparing Neutron Star Kicks to Supernova Remnant Asymmetries

The Pulsar Wind Nebula in G11.2−0.3

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