SN 2017egm

SN 2017egm
SN 2017egm imaged by the Nordic Optical Telescope
Event typeSuperluminous supernova
SLSN-I
Date23 May 2017
08:27:12
InstrumentGaia
ConstellationUrsa Major
Right ascension10h 19m 5.62s
Declination+46° 27′ 14.1″
EpochJ2000
Distance411 Mly (126 Mpc)
Redshift0.030721
HostNGC 3191
Peak apparent magnitude+16.72
Other designationsSN 2017egm, Gaia17biu, iPTF17egm, PS18cn
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SN 2017egm (also known as Gaia17biu) is a hydrogen-poor superluminous supernova (SLSN-I) discovered in 2017. It is notable as the closest known SLSN-I at the time of discovery, occurring in the massive spiral galaxy NGC 3191.

Discovery

SN 2017egm was discovered on 23 May 2017 by the Gaia telescope at an apparent magnitude of 16.72 in the G-Gaia filter. Spectroscopic observations shortly after discovery classified it as a Type I superluminous supernova (SLSN-I). Later studies identified helium features, including strong He Iλ10830 emission and four He I absorption lines, thus reclassifying it within an emerging population of helium-rich SLSNe-I (SLSNe-Ib).

Observation

SN 2017egm exhibits one of the most complex light curves among SLSNe-I. It shows a nearly linear rise to maximum followed by multiple post-peak bumps between 100–350 days after peak. The light curve with multiple post-peak bumps indicates strong indications of interaction with circumstellar material (CSM) and thus may have formed a pulsational pair-instability progenitor two years before the explosion.

References

  1. 1 2 3 4 5 "2017egm | Transient Name Server". www.wis-tns.org. Retrieved 2026-05-11.
  2. 1 2 "SN 2017egm". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-05-11.
  3. ↑ "NGC 3191". NASA/IPAC Extragalactic Database. Retrieved 2026-07-24.
  4. 1 2 3 Bose, Subhash; Dong, Subo; Pastorello, A.; Filippenko, Alexei V.; Kochanek, C. S.; Mauerhan, Jon; Romero-Cañizales, C.; Brink, Thomas G.; Chen, Ping; Prieto, J. L.; Post, R.; Ashall, Christopher; Grupe, Dirk; Tomasella, L.; Benetti, Stefano (2018-01-20). "Gaia17biu/SN 2017egm in NGC 3191: The Closest Hydrogen-poor Superluminous Supernova to Date Is in a "Normal," Massive, Metal-rich Spiral Galaxy". The Astrophysical Journal. 853 (1): 57. arXiv:1708.00864. Bibcode:2018ApJ...853...57B. doi:10.3847/1538-4357/aaa298. ISSN 0004-637X.
  5. ↑ Nicholl, Matt; Berger, Edo; Margutti, Raffaella; Blanchard, Peter K.; Guillochon, James; Leja, Joel; Chornock, Ryan (2017-08-10). "The Superluminous Supernova SN 2017egm in the Nearby Galaxy NGC 3191: A Metal-rich Environment Can Support a Typical SLSN Evolution". The Astrophysical Journal Letters. 845 (1): L8. arXiv:1706.08517. Bibcode:2017ApJ...845L...8N. doi:10.3847/2041-8213/aa82b1. ISSN 2041-8205.
  6. ↑ "NASA's Fermi Glimpses Power Source of Supercharged Supernovae - NASA Science". 2026-05-20. Retrieved 2026-07-26.
  7. ↑ Zhu, Jiazheng; Jiang, Ning; Dong, Subo; Filippenko, Alexei V.; Rudy, Richard J.; Pastorello, A.; Ashall, Christopher; Bose, Subhash; Post, R. S.; Bersier, D.; Benetti, Stefano; Brink, Thomas G.; Chen, Ping; Dou, Liming; Elias-Rosa, N. (2023-05-01). "SN 2017egm: A Helium-rich Superluminous Supernova with Multiple Bumps in the Light Curves". The Astrophysical Journal. 949 (1): 23. arXiv:2303.03424. Bibcode:2023ApJ...949...23Z. doi:10.3847/1538-4357/acc2c3. ISSN 0004-637X.
  8. 1 2 3 Lin, Weili; Wang, Xiaofeng; Yan, Lin; Gal-Yam, Avishay; Mo, Jun; Brink, Thomas G.; Filippenko, Alexei V.; Xiang, Danfeng; Lunnan, Ragnhild; Zheng, Weikang; Brown, Peter; Kasliwal, Mansi; Fremling, Christoffer; Blagorodnova, Nadejda; Mirzaqulov, Davron (2023). "A superluminous supernova lightened by collisions with pulsational pair-instability shells". Nature Astronomy. 7 (7): 779–789. arXiv:2304.10416. Bibcode:2023NatAs...7..779L. doi:10.1038/s41550-023-01957-3. ISSN 2397-3366.

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