Dust Destruction in a Non-Radiative Shock in the Cygnus Loop Supernova Remnant

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

doi:10.1088/0004-637x/712/2/1092

Cited by 39 publications

(50 citation statements)

References 28 publications

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“…In the Cygnus Loop, for example, Braun & Strom (1986) estimated that about 25% of the IRAS 60 μm emission is from the dust in recombined gas in the postshock layer. From their analysis of a non-radiative shock in the Cygnus Loop, Sankrit et al (2010) concluded that the DGR in the ambient medium is about half that of the general ISM. Therefore, it is not impossible that these SNRs do also have DGR values somewhat below that of the general ISM.…”

Section: Snrs With Low Irx Flux Ratiosmentioning

confidence: 99%

Infrared Supernova Remnants and Their Infrared-to-X-Ray Flux Ratios

Koo

Lee

Jeong

et al. 2016

ApJ

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Recent high-resolution infrared space missions have revealed supernova remnants (SNRs) of diverse morphology in infrared (IR) dust emission that are often very different from their X-ray appearance. The observed range of infrared-to-X-ray (IRX) flux ratios of SNRs is also wide. For a sample of 20 Galactic SNRs, we obtain their IR and X-ray properties and investigate the physical causes for such large differences. We find that the observed IRX flux ratios (R IRX,obs ) are related to the IRX morphology, with SNRs with the largest R IRX,obs showing anticorrelated IRX morphology. By analyzing the relation of R IRX,obs to X-ray and IR parameters, we show that the R IRX,obs of some SNRs agrees with theoretical ratios of SNR shocks in which dust grains are heated and destroyed by collisions with plasma particles. For the majority of SNRs, however, R IRX,obs values are either significantly smaller or significantly larger than the theoretical ratios. The latter SNRs have relatively low dust temperatures. We discuss how the natural and/or environmental properties of SNRs could have affected the IRX flux ratios and the IRX morphology of these SNRs. We conclude that the SNRs with largest R IRX,obs are probably located in a dense environment and that their IR emission is from dust heated by shock radiation rather than by collisions. Our result suggests that the IRX flux ratio, together with dust temperature, can be used to infer the nature of unresolved SNRs in external galaxies.

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Section: Snrs With Low Irx Flux Ratiosmentioning

confidence: 99%

Infrared Supernova Remnants and Their Infrared-to-X-Ray Flux Ratios

Koo

Lee

Jeong

et al. 2016

ApJ

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“…These infrared observatories allow one to carry out detailed studies of dust in shock regions, especially near supernova remnants (SNR). While Sankrit et al (2010) and Arendt et al (2010) reported on dust destruction by fast shocks (sputtering) in individual cases (Cygnus Loop SNR and Puppis SNR, respectively, with a reported shock velocity of 350 and 500 km s −1 , respectively), Andersen et al (2011) analyzed 14 young SNRs and found that in most cases, the nearby clouds have seen their grains being shattered from big grains (BG) to very small grain (VSG). The VSG/BG ratio is found to be two to three times higher in the vicinity of the SNRs than in the plane of the Milky Way and the associated shock velocity is entirely in the 50-80 km s −1 range for these sources.…”

Section: Supernovae and Dust Grainsmentioning

confidence: 99%

Absence of coreshine in the Gum/Vela region

Pagani¹,

Lefèvre²,

Bacmann³

et al. 2012

A&A

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Context. We recently discovered mid-infrared light scattering by micron-size grains deeply buried in dark clouds. We have named this coreshine. We also showed that this effect is widespread across the Galaxy except in the Gum/Vela region, the only region among those we explored without any trace of coreshine. Aims. We aim to check whether the Gum/Vela situation is a chance effect or if coreshine is really absent from the region. Methods. We explored the entire available Spitzer/InfraRed Red Array Camera (IRAC) archive centered on the Gum/Vela region in search of the coreshine effect. Results. Out of 24 validated objects (of a total of 32), we found three cases of coreshine and three possible other cases, while we detect nine cases of non-coreshine emission (bright rimmed clouds -BRC -or polycyclic aromatic hydrocarbon -PAH -emission). This is markedly different from our previous galactic-wide survey with a ratio of 7-8 coreshine cases per PAH case. In Gum/Vela, a majority of the clouds with protostars or young stellar objects do not show a coreshine effect, while in the galactic-wide survey, 75% of the protostellar clouds do. Conclusions. The rare occurence of coreshine, outnumbered by PAH and BRC cases, together with a large number of protostars, let us conclude that the Gum Nebula is a supernova remnant (SNR), and that the blast wave has both reset the grain size distribution and induced the formation of several protostars. The absence of coreshine in the vicinity of several of the Class I objects also implies that the growth time for grains to efficiently scatter mid-infrared radiation exceeds the Class I life duration, which is typically 2 × 10 5 years, and it also implies that the blast wave has reached these clouds only recently despite the age of the Gum region (over 1.5 My). This is consistent with their large distance from the center of the SNR.

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“…Diagnoses of the ISM by the relative strengths of unidentified infrared (UIR) features are in progress (e.g., Mori et al 2013). The 3.3 micron band gives critical information on the dust size distribution and relative abundance, key knowledge on the formation and destruction process of dust in shocked regions (Cyg loop: Sankrit et al 2010;Pup A: Arendt et al 2010;Andersen et al 2011). UIR band carriers in BCDs are suggested to be large, with small carriers having been destroyed.…”

Section: Dustmentioning

confidence: 99%