New supernova remnant G321.3-3.9 unveiled with multi-wavelength data

Astronomers at Curtin University in Australia and collaborators worldwide: the identification of a novel supernova remnant (SNR) located approximately 3,300 light years away. Dubbed G321.3-3.9, this newly found SNR boasts an elliptical form and is believed to be a few millennia old. The revelation was recently unveiled in a paper published on Jan. 30 via the arXiv pre-print server.

SNRs, diffuse and expanding entities, manifest following the cataclysmic explosion of a supernova. They encompass both ejected matter propelled from the explosion and interstellar material swept up by the ensuing shockwave from the detonated star.

Insights gleaned from studying supernova remnants are pivotal for astronomers. These remnants significantly influence galaxy evolution by disseminating heavy elements synthesized during the supernova blast and energizing the interstellar medium. Moreover, SNRs are implicated in the acceleration of galactic cosmic rays.

G321.3-3.9, identified as an SNR candidate in 1997, has been subject to prior scrutiny. Past observations unveiled its elliptical, nearly complete shell, spanning 109×64 arcmin2, boasting a peak flux of 10 mJy/beam and a total integrated flux density surpassing 0.37 Jy.

In their latest investigation, a consortium spearheaded by Curtin University’s Silvia Mantovanini meticulously analyzed copious radio and X-ray data from diverse surveys, augmented by observations from the Spektr-RG spacecraft, culminating in the confirmation of G321.3-3.9’s SNR status.

Examination revealed an elongated structure at low X-ray energies enveloped by a radio shell, with no discernible diffuse emission in the infrared spectrum. The source’s spectral index, gauged at -0.8, aligns with non-thermal synchrotron emission characteristic of a shell-type SNR.

Drawing on amassed data, researchers approximated G321.3-3.9’s distance to be situated between 2,300 and 3,300 light years. Estimates suggest the SNR spans a diameter of approximately 62–97 light years, with an age falling within the 1,700–4,000-year range. Notably, the assumed age skews younger than anticipated based on the shell’s morphology and subdued radio luminosity.

Acknowledging inherent uncertainties stemming from scant photon statistics in X-rays and the absence of an association between the shell and a known pulsar, astronomers emphasize the need for further investigation. They underscore plans for PARKES follow-up observations within the remnant shell in the radio band, seeking to unearth a potential pulsar association. Successful detection of pulsations could facilitate determination of the dispersion measure, thereby shedding light on G321.3-3.9’s age, distance, and expansion velocity.

The discovery of G321.3-3.9 epitomizes the relentless pursuit of knowledge fueling astronomical exploration, unraveling the enigmatic tapestry of the universe one celestial phenomenon at a time.

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