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Diprotodon on the sky. The Large Galactic Supernova Remnant (SNR) G278.94+1.35

Fuente: arXiv

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Main Authors:	Filipović, Miroslav D., Lazarević, S., Araya, M., Hurley-Walker, N., Kothes, R., Sano, H., Rowell, G., Martin, P., Fukui, Y., Alsaberi, R. Z. E., Arbutina, B., Ball, B., Bordiu, C., Brose, R., Bufano, F., Burger-Scheidlin, C., Collins, T. A., Crawford, E. J., Dai, S., Duchesne, S. W., Fuller, R. S., Hopkins, A. M., Ingallinera, A., Inoue, H., Jarrett, T. H., Koribalski, B. S., Leahy, D., Luken, K. J., Mackey, J., Macgregor, P. J., Norris, R. P., Payne, J. L., Riggi, S., Riseley, C. J., Sasaki, M., Smeaton, Z. J., Sushch, I., Stupar, M., Umana, G., Urošević, D., Velović, V., Vernstrom, T., Vukotić, B., West, J.
Format:	Preprint
Published:	2024
Subjects:	High Energy Astrophysical Phenomena
Online Access:	Acceder al recurso
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author	Filipović, Miroslav D. Lazarević, S. Araya, M. Hurley-Walker, N. Kothes, R. Sano, H. Rowell, G. Martin, P. Fukui, Y. Alsaberi, R. Z. E. Arbutina, B. Ball, B. Bordiu, C. Brose, R. Bufano, F. Burger-Scheidlin, C. Collins, T. A. Crawford, E. J. Dai, S. Duchesne, S. W. Fuller, R. S. Hopkins, A. M. Ingallinera, A. Inoue, H. Jarrett, T. H. Koribalski, B. S. Leahy, D. Luken, K. J. Mackey, J. Macgregor, P. J. Norris, R. P. Payne, J. L. Riggi, S. Riseley, C. J. Sasaki, M. Smeaton, Z. J. Sushch, I. Stupar, M. Umana, G. Urošević, D. Velović, V. Vernstrom, T. Vukotić, B. West, J.
author_facet	Filipović, Miroslav D. Lazarević, S. Araya, M. Hurley-Walker, N. Kothes, R. Sano, H. Rowell, G. Martin, P. Fukui, Y. Alsaberi, R. Z. E. Arbutina, B. Ball, B. Bordiu, C. Brose, R. Bufano, F. Burger-Scheidlin, C. Collins, T. A. Crawford, E. J. Dai, S. Duchesne, S. W. Fuller, R. S. Hopkins, A. M. Ingallinera, A. Inoue, H. Jarrett, T. H. Koribalski, B. S. Leahy, D. Luken, K. J. Mackey, J. Macgregor, P. J. Norris, R. P. Payne, J. L. Riggi, S. Riseley, C. J. Sasaki, M. Smeaton, Z. J. Sushch, I. Stupar, M. Umana, G. Urošević, D. Velović, V. Vernstrom, T. Vukotić, B. West, J.
contents	We present a re-discovery of G278.94+1.35 as possibly one of the largest known Galactic supernova remnants (SNR) - that we name Diprotodon. While previously established as a Galactic SNR, Diprotodon is visible in our new EMU and GLEAM radio continuum images at an angular size of 3.33x3.23 deg, much larger than previously measured. At the previously suggested distance of 2.7 kpc, this implies a diameter of 157x152 pc. This size would qualify Diprotodon as the largest known SNR and pushes our estimates of SNR sizes to the upper limits. We investigate the environment in which the SNR is located and examine various scenarios that might explain such a large and relatively bright SNR appearance. We find that Diprotodon is most likely at a much closer distance of $\sim$1 kpc, implying its diameter is 58x56 pc and it is in the radiative evolutionary phase. We also present a new Fermi-LAT data analysis that confirms the angular extent of the SNR in gamma-rays. The origin of the high-energy emission remains somewhat puzzling, and the scenarios we explore reveal new puzzles, given this unexpected and unique observation of a seemingly evolved SNR having a hard GeV spectrum with no breaks. We explore both leptonic and hadronic scenarios, as well as the possibility that the high-energy emission arises from the leftover particle population of a historic pulsar wind nebula.
format	Preprint
id	arxiv_https___arxiv_org_abs_2412_20836
institution	arXiv
publishDate	2024
record_format	arxiv
spellingShingle	Diprotodon on the sky. The Large Galactic Supernova Remnant (SNR) G278.94+1.35 Filipović, Miroslav D. Lazarević, S. Araya, M. Hurley-Walker, N. Kothes, R. Sano, H. Rowell, G. Martin, P. Fukui, Y. Alsaberi, R. Z. E. Arbutina, B. Ball, B. Bordiu, C. Brose, R. Bufano, F. Burger-Scheidlin, C. Collins, T. A. Crawford, E. J. Dai, S. Duchesne, S. W. Fuller, R. S. Hopkins, A. M. Ingallinera, A. Inoue, H. Jarrett, T. H. Koribalski, B. S. Leahy, D. Luken, K. J. Mackey, J. Macgregor, P. J. Norris, R. P. Payne, J. L. Riggi, S. Riseley, C. J. Sasaki, M. Smeaton, Z. J. Sushch, I. Stupar, M. Umana, G. Urošević, D. Velović, V. Vernstrom, T. Vukotić, B. West, J. High Energy Astrophysical Phenomena We present a re-discovery of G278.94+1.35 as possibly one of the largest known Galactic supernova remnants (SNR) - that we name Diprotodon. While previously established as a Galactic SNR, Diprotodon is visible in our new EMU and GLEAM radio continuum images at an angular size of 3.33x3.23 deg, much larger than previously measured. At the previously suggested distance of 2.7 kpc, this implies a diameter of 157x152 pc. This size would qualify Diprotodon as the largest known SNR and pushes our estimates of SNR sizes to the upper limits. We investigate the environment in which the SNR is located and examine various scenarios that might explain such a large and relatively bright SNR appearance. We find that Diprotodon is most likely at a much closer distance of $\sim$1 kpc, implying its diameter is 58x56 pc and it is in the radiative evolutionary phase. We also present a new Fermi-LAT data analysis that confirms the angular extent of the SNR in gamma-rays. The origin of the high-energy emission remains somewhat puzzling, and the scenarios we explore reveal new puzzles, given this unexpected and unique observation of a seemingly evolved SNR having a hard GeV spectrum with no breaks. We explore both leptonic and hadronic scenarios, as well as the possibility that the high-energy emission arises from the leftover particle population of a historic pulsar wind nebula.
title	Diprotodon on the sky. The Large Galactic Supernova Remnant (SNR) G278.94+1.35
topic	High Energy Astrophysical Phenomena
url	https://arxiv.org/abs/2412.20836