The Youngest Galactic Supernova Remnant: G1.9+0.3

By S. Reynolds, K. Borkowski, Douglas R. Green, U. Hwang, I. Harrus, R. Petre. 2008

139 citations recorded by the source corpus.

Our 50 ks Chandra observation of the small radio supernova remnant (SNR) G1.9+0.3 shows a complete shell structure with strong bilateral symmetry, about 100″ in diameter. The radio morphology is also shell-like, but only about 84″ in diameter, based on observations made in 1985. We attribute the size difference to expansion between 1985 and our Chandra observations of 2007. Expansion is confirmed in comparing radio images from 1985 and 2008. We deduce that G1.9+0.3 is of order 100 years old—the youngest supernova remnant in the Galaxy. Based on a very high absorbing column density of 5.5 × 1022 cm−2, we place G1.9+0.3 near the Galactic center, at a distance of about 8.5 kpc, where the mean remnant radius would be about 2 pc, and the required expansion speed about 14,000 km s−1. The X-ray spectrum is featureless and well described by the exponentially cut off synchrotron model srcut. With the radio flux at 1 GHz fixed at 0.9 Jy, we find a spectral index of 0.65 and a rolloff frequency of 1.4 × 1018 Hz. The implied characteristic rolloff electron energy of about 94(B/10 μ G)−1/2 TeV is the highest ever reported for a shell supernova remnant. It can easily be reached by standard diffusive shock acceleration, given the very high shock velocities; it can be well described by either age-limited or synchrotron-loss-limited acceleration. Not only is G1.9+0.3 the youngest known Galactic remnant, it is also only the fourth Galactic X-ray-synchrotron-dominated shell supernova remnant.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/d2e563839e45801a8218162a8db85e67b6333ac8

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In Astronomy and Astrophysics

1. D. Vartanyan
2. V. Morozova
3. David Radice
4. C. Fransson
5. B. Gaensler
6. F. Bocchino
7. Raffaella Margutti
8. W. Fong

In Nuclear and High Energy Physics

1. D. Vartanyan
2. David Radice
3. C. Fransson
4. Adam Burrows
5. V. Morozova
6. B. Gaensler
7. F. Bocchino
8. C. Badenes

Citations in the corpus

• Nonrelativistic Collisionless Shocks in Unmagnetized Electron-Ion Plasmas (2008, background): “For younger SNRs with higher shock speeds of ≥10,000 km s 1 (e.g., Reynolds et al. 2008), these shocks would be formed more easily.”
• Magnetic Fields in Supernova Remnants and Pulsar-Wind Nebulae (2011, background): “9+0.3, but it is also suspected to be a Type Ia remnant (Reynolds et al. 2008).”
• A revised catalogue of 294 Galactic supernova remnants (2019, unknown): “9+0.3 (e.g. Green et al. 2008; Reynolds et al. 2008).”
• The Gravitational Wave Signal from Core-collapse Supernovae (2018, background): “Given that the estimate for the galactic CCSNe rate is 3.2+7.3−2.6 per century (Li et al. 2011; Adams et al. 2013), and the youngest known galactic CCSN remnant is ∼100 years old (Reynolds et al. 2008; Borkowski et al. 2017), chances are high that we will not have long to wait.”
• EVLA OBSERVATIONS CONSTRAIN THE ENVIRONMENT AND PROGENITOR SYSTEM OF Type Ia SUPERNOVA 2011fe (2012, background): “9+0.3, is likely the remnant of a SN Ia that exploded ∼100 years ago, and is also consistent with low-density surroundings (∼0.03 cm−3; Reynolds et al. 2008; Borkowski et al. 2010; Carlton et al. 2011).”