Wikipedia

SGR 1935+2154

SGR 1935+2154 (or SGR J1935+2154) is a soft gamma repeater (SGR) that is an ancient stellar remnant, in the constellation Vulpecula, originally discovered in 2014 by the Neil Gehrels Swift Observatory.[3] Currently, the SGR-phenomena and the related anomalous X-ray pulsars (AXP) are explained as arising from magnetars. On 28 April 2020, this remnant about 30,000 light-years away in our Milky Way galaxy was observed to be associated with a very powerful radio pulse known as a fast radio burst or FRB (designated FRB 200428),[4] and a related X-ray flare.[5][6][7] The detection is notable as the first FRB detected inside the Milky Way, and the first to be linked to a known source.[8][9][10][11] Later in 2020, SGR 1935+2154 was found to be associated with repeating fast radio bursts.[12]

SGR 1935+2154

Example of a fast radio burst (FRB) from outer space to Earth (artist concept)
Observation data
Epoch J2000      Equinox J2000
Constellation Vulpecula
Right ascension 19h 35m
Declination +21° 54'
Apparent magnitude (V) ?
Astrometry
Distance21,500–28,400 ly
(6,600[1]–8,800[2] pc)
Details
Mass1.4 (assumed)[2] M☉
Radius4.35+1.95
−1.35[1] km
Database references
SIMBADdata
Other designations

History

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The Swift Burst Alert Telescope first alerted the astronomical community to an increase in activity from the remnant with the detection of a flare on 27 April 2020.[13] The next day, the Canadian Hydrogen Intensity Mapping Experiment (CHIME)[6][7] first reported the detection of two bright radio bursts from 400 MHz to 800 MHz in the direction of the remnant, establishing the link between radio emission and the remnant. They estimated that the bursts had an energy similar to the brightest giant pulses from the Crab pulsar,[7][14] which had never been seen from a magnetar. An independent detection of the bursts at 1.4 GHz by the STARE2[15] team established that the burst, now named FRB 200428, is similar to the fast radio bursts (FRBs) at extragalactic distances with their report that the fluence of the burst must be >1.5 MJy ms,[16] more than a thousand times that reported by CHIME. At the distance of the closest known fast radio burst, FRB 200428 would have been detected with a fluence of >7 mJy ms.[16] The INTEGRAL, Konus-Wind, Insight-HXMT, and AGILE telescopes then reported the detection of an X-ray burst from SGR 1935+2154 that occurred at the same time as the CHIME and STARE2 bursts,[17][18][19][20] marking the first time an FRB had been associated with an X-ray source. To further secure the association of FRB 200428 with the remnant, the Five-hundred-meter Aperture Spherical Telescope (FAST) reported the detection of a much weaker radio burst,[21] which was localized to within a maximal margin of error of a few arcminutes of the position of the remnant with a dispersion measure consistent with those reported by STARE2 and CHIME.

The NuSTAR, Swift, and NICER satellites observed several short X-ray bursts from the remnant on 29 April 2020 and 30 April 2020, confirming the magnetar was still in an active phase.[22] The Very Large Array (VLA) followed the remnant 1–2 days after FRB 200428 and did not find any pulsed radio emission or an afterglow.[23][24] The Deep Space Network (DSN) observed the remnant 1.5 to 3.5 days after the FRB and did not find evidence of periodic emission.[25] LOFAR searched for other pulses from the remnant 1.5 days after FRB 200428 at 145 MHz and did not find any.[26] Arecibo did not detect any bursts during a period of activity from the remnant in October 2019.[27] Spektr-RG observed the remnant four days prior to FRB 200428 and found no evidence of flaring activity.[28] Follow-up studies and observations have been reported.[29][30][31][32][33][34][35] On 4 June 2020, astronomers reported "periodic radio pulsations" from the remnant with the Medicina Northern Cross (MNC) radio observatory on 30 May 2020.[36] Another study was reported on 6 June 2020 of observations made earlier with the European VLBI Network on 13 May 2020.[37] There have been other reported observations as well.[38][39][40][41][42][43][44]

Planetary system

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The repeated X-ray bursts are easily explained by collisions of fragments caused by the partial tidal disruption of a small planet. These fragments escape from the planet's surface and fall on SGR 1935+2154, creating the X-ray bursts. This planet has a very eccentric orbit, estimated at 0.992 or 0.994. Its orbital period around SGR 1935+2154 is of either 238 or 298 days. For the lower period, a planet composed by iron with a mass of 18.1 ME and radius of 1.6 R🜨 would form the fragments, while for larger period it would be either a planet of iron with a mass of 10.1–18.1 ME and a radius of 1.4–1.6 R🜨, a planet of magnesium sulfite with a mass 18.2 ME and radius 2.5 R🜨, or a two-layer planet of 12.8 ME and 1.6 R🜨.[2]

The SGR 1935+2154 planetary system[2]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b (unconfirmed) 10.1–18.2 M🜨 0.85 or 1.19 238 or 398 0.992 or 0.994 — 1.4–2.5 R🜨

See also

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  • SGR J1745−2900 – the first discovered magnetar, orbiting the black hole Sagittarius A*, in the center of the Milky Way

References

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  1. ^ a b Shao, Yi-Xuan; Zhou, Ping; Li, Xiang-Dong; Zhang, Bin-Bin; Castro-Tirado, Alberto Javier; Wang, Pei; Li, Di; Zhang, Zeng-Hua; Zhang, Zi-Jian (1 October 2024). "GTC optical/NIR upper limits and NICER X-ray analysis of SGR J1935+2154 for the outburst in 2022". arXiv:2410.00635 [astro-ph.HE].
  2. ^ a b c d Kurban, Abdusattar; Zhou, Xia; Wang, Na; Huang, Yong-Feng; Wang, Yu-Bin; Nurmamat, Nurimangul (June 2024). "Repeating X-ray bursts: Interaction between a neutron star and clumps partially disrupted from a planet". Astronomy & Astrophysics. 686: A87. arXiv:2403.13333v1. Bibcode:2024A&A...686A..87K. doi:10.1051/0004-6361/202347828. ISSN 0004-6361.
  3. ^ Cummings, J.R.; et al. (6 July 2014). "ATel #6294: Newly discovered SGR 1935+2154: Swift observations". The Astronomer's Telegram. Retrieved 27 February 2021.
  4. ^ Zhang, S.-N.; et al. (29 April 2020). "ATel #13687: Insight-HXMT detection of a bright short x-ray counterpart of the Fast Radio Burst from SGR 1935+2154". The Astronomer's Telegram. Retrieved 4 May 2020.
  5. ^ Drake, Nadia (5 May 2020). "'Magnetic Star' Radio Waves Could Solve the Mystery of Fast Radio Bursts - The surprise detection of a radio burst from a neutron star in our galaxy might reveal the origin of a bigger cosmological phenomenon". Scientific American. Retrieved 9 May 2020.
  6. ^ a b Starr, Michelle (1 May 2020). "Exclusive: We Might Have First-Ever Detection of a Fast Radio Burst in Our Own Galaxy". ScienceAlert.com. Retrieved 1 May 2020.
  7. ^ a b c Scholz, Paul; et al. (28 April 2020). "ATel #13681: A bright millisecond-timescale radio burst from the direction of the Galactic magnetar SGR 1935+2154". The Astronomer's Telegram. Retrieved 1 May 2020.
  8. ^ Hall, Shannon (11 June 2020). "A Surprise Discovery Points to the Source of Fast Radio Bursts - After a burst lit up their telescope "like a Christmas tree," astronomers were able to finally track down the source of these cosmic oddities". Quantum Magazine. Retrieved 11 June 2020.
  9. ^ Timmer, John (4 November 2020). "We finally know what has been making fast radio bursts - Magnetars, a type of neutron star, can produce the previously enigmatic bursts". Ars Technica. Retrieved 4 November 2020.
  10. ^ Cofield, Calla; Andreoli, Calire; Reddy, Francis (4 November 2020). "NASA Missions Help Pinpoint the Source of a Unique X-ray, Radio Burst". NASA. Retrieved 4 November 2020.
  11. ^ Andersen, B.; et al. (4 November 2020). "A bright millisecond-duration radio burst from a Galactic magnetar". Nature. 587 (7832): 54–58. arXiv:2005.10324. Bibcode:2020Natur.587...54C. doi:10.1038/s41586-020-2863-y. PMID 33149292. S2CID 218763435. Retrieved 5 November 2020.
  12. ^ Starr, Michelle (16 November 2020). "It's Official: The Fast Radio Burst Coming From Within Our Galaxy Is Repeating". ScienceAlert. Retrieved 17 November 2020.
  13. ^ Palmer, David (27 April 2020). "Swift detection of multiple bursts from SGR 1935+2154". GCN Circulars. 27657: 1. Bibcode:2020GCN.27657....1B.
  14. ^ Cordes, J. M.; Bhat, N. D. R.; Hankins, T. H.; McLaughlin, M. A.; Kern, J. (September 2004). "The Brightest Pulses in the Universe: Multifrequency Observations of the Crab Pulsar's Giant Pulses". The Astrophysical Journal. 612 (1): 375–388. arXiv:astro-ph/0304495. Bibcode:2004ApJ...612..375C. doi:10.1086/422495. ISSN 0004-637X. S2CID 252457.
  15. ^ Bochenek, Christopher D.; McKenna, Daniel L.; Belov, Konstantin V.; Kocz, Jonathon; Kulkarni, Shri R.; Lamb, James; Ravi, Vikram; Woody, David (1 March 2020). "STARE2: Detecting Fast Radio Bursts in the Milky Way". Publications of the Astronomical Society of the Pacific. 132 (1009): 034202. arXiv:2001.05077. Bibcode:2020PASP..132c4202B. doi:10.1088/1538-3873/ab63b3. ISSN 0004-6280. S2CID 210718502.
  16. ^ a b "ATel #13684: Independent detection of the radio burst reported in ATel #13681 with STARE2". ATel. Retrieved 15 May 2020.
  17. ^ "ATel #13685: INTEGRAL IBIS and SPI-ACS detection of a hard X-ray counterpart of the radio burst from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  18. ^ "ATel #13686: AGILE detection of a hard X-ray burst in temporal coincidence with a radio burst from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  19. ^ "ATel #13687: Insight-HXMT detection of a bright short x-ray counterpart of the Fast Radio Burst from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  20. ^ "ATel #13688: Konus-Wind observation of hard X-ray counterpart of the radio burst from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  21. ^ Zhang, C.F.; et al. (3 May 2020). "ATel #13699: A highly polarised radio burst detected from SGR 1935+2154 by FAST". The Astronomer's Telegram. Retrieved 3 May 2020.
  22. ^ "ATel #13720: Â X-ray monitoring of the active magnetar SGR 1935+2154". ATel. Retrieved 15 May 2020.
  23. ^ "ATel #13690: VLA search for persistent and bursting emission from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  24. ^ "ATel #13693: VLA Monitoring of SGR 1935+2154 on 2020, April 30". ATel. Retrieved 15 May 2020.
  25. ^ "ATel #13713: A Search for Radio Bursts and Periodic Emission from SGR 1935+214 at High Radio Frequencies using the Deep Space Network". ATel. Retrieved 15 May 2020.
  26. ^ "ATel #13707: A LOFAR high time resolution search for radio bursts from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  27. ^ "ATel #13726: Arecibo search for radio bursts following a previous SGR-like activity from SGR 1935+2154". ATel. Retrieved 15 May 2020.
  28. ^ "ATel #13723: SRG observations of SGR 1935+2154: four days prior to the FRB event". ATel. Retrieved 15 May 2020.
  29. ^ Naldi, Giovanni; et al. (17 May 2020). "ATel #13739: Search for radio bursts from SGR 1935+2154 at 408 MHz with the Northern Cross". The Astronomer's Telegram. Retrieved 17 May 2020.
  30. ^ Tohuvavohu, Aaron (21 May 2020). "ATel #13748: SGR 1935+2154: A catalog of X-ray burst times from Swift/BAT during the ongoing 2020 activity period". The Astronomer's Telegram. Retrieved 22 May 2020.
  31. ^ Tohuvavohu, Aaron (23 May 2020). "ATel #13758: SGR 1935+2154: A complete catalog of X-ray burst times from Swift/BAT imaging". The Astronomer's Telegram. Retrieved 24 May 2020.
  32. ^ Surnis, Mayuresh; et al. (30 May 2020). "ATel #13769: A search for radio pulsations from SGR J1935+2154". The Astronomer's Telegram. Retrieved 30 May 2020.
  33. ^ Bera, Apurba; et al. (1 June 2020). "ATel #13773: A uGMRT search for low-frequency persistent radio emission and afterglow from SGR 1935+2154". The Astronomer's Telegram. Retrieved 1 June 2020.
  34. ^ Surnis, Mayuresh; et al. (3 June 2020). "ATel #13777: Radio pulsation and imaging study of SGR J1935+2154 with the uGMRT". The Astronomer's Telegram. Retrieved 4 June 2020.
  35. ^ Roy, Jayanta; et al. (4 June 2020). "ATel #13778: Search for radio pulsations from SGR 1935+2154 with the uGMRT". The Astronomer's Telegram. Retrieved 4 June 2020.
  36. ^ Burgay, M.; et al. (4 June 2020). "ATel #13783: Marginal detection of radio pulsations from the magnetar SGR 1935+2154 with the Medicina Northern Cross". The Astronomer's Telegram. Retrieved 5 June 2020.
  37. ^ Nimmo, K.; et al. (6 June 2020). "ATel #13786: A search for persistent radio emission and millisecond-duration radio bursts from SGR 1935+2154 using the European VLBI Network". The Astronomer's Telegram. Retrieved 6 June 2020.
  38. ^ Surnis, Mayurexh; et al. (10 June 2020). "ATel #13799: Radio pulsation and imaging study of SGR J1935+2154 with the uGMRT". The Astronomer's Telegram. Retrieved 11 June 2020.
  39. ^ An, Tao; et al. (19 June 2020). "ATel #13816: MWA low-frequency radio imaging of SGR 1935+2154". The Astronomer's Telegram. Retrieved 19 June 2020.
  40. ^ Tan, Chia Min; et al. (29 June 2020). "ATel #13838 - Non-detection of radio pulsations from SGR1935+2154 by CHIME/Pulsar". The Astronomer's Telegram. Retrieved 29 June 2020.
  41. ^ Straal. Samayra; et al. (5 November 2020). "ATel #14151 - Search for burst and periodic radio emission from SGR1935+2154 using GBT observations at 800 MHz and S-band". The Astronomer's Telegram. Retrieved 6 November 2020.
  42. ^ Alexander, Rodin; Fedorova, Viktoriya (17 November 2020). "ATel #14186: Detection of radio emission from SGR 1935+2154 at the frequency 111 MHz". The Astronomer's Telegram. Retrieved 17 November 2020.
  43. ^ Kirsten, Franz; et al. (9 February 2021). "ATel #14382: Upper limits on the radio fluence of the most recent X-ray bursts from SGR1935+21". The Astronomer's Telegram. Retrieved 15 February 2021.
  44. ^ Borghese. A.; et al. (12 February 2021). "ATel#14388: Swift observation of the magnetar SGR 1935+2154 following the detection of several bursts". The Astronomer's Telegram. Retrieved 13 February 2021.
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