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

Borkowski, Kazimierz J.; Lyerly, W. J.; Reynolds, Stephen P.

doi:10.1086/319011

Cited by 418 publications

(431 citation statements)

References 37 publications

Supporting

Mentioning

417

Contrasting

Unclassified

Order By: Relevance

“…The contribution to the total intensity of each emission line due to this model ("baseline model" hereafter) is given in the rightmost column of Table 2. A multiple-temperature structure could be the results of fitting a single temperature non-equilibrium ionisation plasma. We have tested this hypothesis by alternatively fitting the RGS spectrum with a single vnei (Borkowski et al 2001) model in Xspec. The resulting C-statistics is worse (6857.7/4422 d.o.f.…”

Section: Thermal Fit Of the Overall Rgs Spectrummentioning

confidence: 99%

AGN/starburst connection in action: the half million second RGS spectrum of NGC 1365

Guainazzi¹,

Risaliti

Nucita³

et al. 2009

A&A

View full text Add to dashboard Cite

Context. High-resolution X-ray observations in the imaging and spectral domain have recently opened a new window on active galactic nuclei (AGN) feedback onto the circumnuclear gas. Spectral diagnostics, as well as the remarkable morphological coincidence between [O iii] and X-rays, point to AGN photoionisation as the dominant ionisation mechanism on scales as large as a few kpc.Aims. In this paper we extend these studies to the nearby Seyfert 2 galaxy NGC 1365, known to host a circumnuclear ring of intense star formation at 1.3 kpc from the nucleus. The main scope of this investigation is to study the connection between nuclear activity and star formation in nearby AGN. Methods. We present a deep ( 5.8 days) 0.3-2 keV high-resolution spectrum of NGC 1365, collected with the reflection grating spectrometer (RGS) on board XMM-Newton. Results. The spectrum is dominated by strong recombination lines of He-and H-like transitions from carbon to silicon, as well as by L transitions from Fexvii. The continuum is strong, especially in the 10 to 20 Å range. Formal fits require two optically thin, collisionally ionised plasma components, with temperatures 300 and 640 eV. However, they leave the bulk of the forbidden components of the He-α Ovii and Nvi triplets unaccounted for. These features can be explained as being produced by photoionised gas. NGC 1365 is therefore the first obscured AGN, whose high-resolution X-ray spectrum requires both collisional ionisation and photoionisation. Conclusions. The relative weakness of photoionisation does not stem from the intrinsic weakness of its AGN, whose X-ray luminosity is ∼ > 10 42 erg s −1 . We suggest that it may instead come from the line-of-sight from the active nucleus to the NLR being blocked by optically thick matter in the broad line region, at the same time responsible for the large observed variation of the column density obscuring the X-ray active nucleus. Alternatively, NGC 1365 could host a remarkably luminous nuclear starburst when compared to the AGN accretion power.

show abstract

Section: Thermal Fit Of the Overall Rgs Spectrummentioning

confidence: 99%

AGN/starburst connection in action: the half million second RGS spectrum of NGC 1365

Guainazzi¹,

Risaliti

Nucita³

et al. 2009

A&A

View full text Add to dashboard Cite

show abstract

“…The soft component has been associated with the shocked interstellar material, and the hot component with the shocked stellar ejecta. Therefore, we used the same emission models, namely the mekal model (Mewe et al 1985) and the VNEI (Borkowski et al 2001) model of XSPEC v11.3.2 (Arnaud 1996). We fixed the chemical abundances of the soft component to solar values, and allowed the abundances of the hot component to vary.…”

Section: Ic 443mentioning

confidence: 99%

On the metal abundances inside mixed-morphology supernova remnants: the case of IC 443 and G166.0+4.3

Bocchino

Miceli

Troja

2009

A&A

View full text Add to dashboard Cite

Context. Recent developments in the study of mixed morphology supernova remnants (MMSNRs) have revealed the presence of metal-rich X-ray emitting plasma inside a fraction of these remnants, a feature not properly addressed by traditional models for these objects. Aims. Radial profiles of thermodynamical and chemical parameters are needed for a fruitful comparison of data and model of MMSNRs, but these are available only in a few cases. Methods. We analyzed XMM-Newton data of two MMSNRs, namely IC 443 and G166.0+4.3, previously known to have solar metal abundances, and performed a spatially resolved spectral analysis of the X-ray emission. Results. We detected enhanced abundances of Ne, Mg and Si in the hard X-ray bright peak in the north of IC 443, and of sulphur in the outer regions of G166.0+4.3. The metal abundances are not distributed uniformly in both remnants. The evaporating clouds model and the radiative SNR model fail to reproduce consistently all the observational results. Conclusions. We suggest that further deep X-ray observations of MMSNRs may reveal more metal-rich objects. More detailed models including ISM-ejecta mixing are needed to explain the nature of this growing subclass of MMSNRs.

show abstract

“…It is not the purpose of this paper to provide definitive modeling of the thermal components of the spectra obtained of SN 1006. Nevertheless, we have fitted the spectra of both regions (NE-2 and NE-3) with plane-parallel shock models (with variable abundances: XSPEC model vpshock; Borkowski, Lyerly, & Reynolds 2001) plus sresc models with radio spectral index fixed at 0.54 and absorption fixed at 8:9 Â 10 20 cm À2 . The fits with and without the nonthermal component have similar values of 2 , but the latter involve some implausibilities (in region NE-3, the ionization timescale for a pure thermal model is only 54 cm À3 yr, required to keep lines as weak as observed).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

“…A smaller ionization timescale of about 50 cm À3 yr might allow the 0.6 keV electron temperature, but it would fail to produce the observed He-like ions of Mg and Si. Plane-shock models with different initial ion and electron temperatures are also available in XSPEC (models npshock and vnpshock; Borkowski et al 2001), and so we have experimented with them as well. The best-fit vnpshock model with the mean ion+electron temperature fixed at 9.8 keV and with the Ne abundance free (because of well-known concerns with its solar abundance) but all other elements at solar abundances is shown in the top left panel of Figure 9.…”

Section: The Thermally Dominated Northwest Limbmentioning

confidence: 99%

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

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

Cited by 418 publications

References 37 publications

AGN/starburst connection in action: the half million second RGS spectrum of NGC 1365

AGN/starburst connection in action: the half million second RGS spectrum of NGC 1365

On the metal abundances inside mixed-morphology supernova remnants: the case of IC 443 and G166.0+4.3

ChandraCCD Imagery of the Northeast and Northwest Limbs of SN 1006

Contact Info

Product

Resources

About