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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

11528 results found.

  1. GRB 200524A: Kitab observatory afterglow observations
  2. GRB 200525A: Fermi GBM Final Real-time Localization
  3. GRB 200524A: AstroSat CZTI detection
  4. GRB 200524A: Further Liverpool Telescope observations
  5. Fermi-LAT Gamma-ray Observations of IceCube-190523A
  6. GRB200521A: ASIM observation
  7. GRB 200524A: KAIT Optical Observations
  8. GRB 200524A: MITSuME Akeno optical observation
  9. GRB 200524A: Swift-XRT afterglow detection
  10. GRB 200524A: OAJ multicolor afterglow detection
  11. GRB 200524A: Fermi GBM detection
  12. GRB 200524A: CAHA multicolor afterglow detection
  13. GRB 200524A: CrAO observations of ZTF20abbiixp
  14. Fermi GRB 200524A: Global MASTER-Net observations report
  15. ZTF Discovery of ZTF20abbiixp: The Likely Optical Afterglow to GRB 200524A
  16. GRB 200524A: Swift ToO observations
  17. GRB 200524A: Fermi-LAT detection
  18. Konus-Wind detection of short/hard GRB 200521A
  19. IPN triangulation of GRB 200521A (short)
  20. IceCube-200523A: Upper limits from Fermi-GBM Observations
  21. IceCube-200523A - IceCube observation of a high-energy neutrino candidate event
  22. Fermi GRB 200522B: Global MASTER-Net observations report
  23. GRB 200522B: Fermi GBM Final Real-time Localization
  24. GRB 200514B: Fermi GBM observation
  25. Fermi trigger No 611676654: Global MASTER-Net observations report
  26. Fermi trigger No 611605955: Global MASTER-Net observations report
  27. Fermi GBM Sub-Threshold Detection of GRB 200517A
  28. IPN triangulation of GRB 200514B (short)
  29. Fermi trigger No 611434353: Global MASTER-Net observations report
  30. GRB 200514B: BALROG localization (Fermi Trigger 611140062 / GRB 200514380)
  31. GRB 200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062) - More Candidates
  32. GRB200514B: YSE detection of ZTF20aazpphd
  33. Optical transient ZTF20aazpphd is unrelated to GRB 200514B
  34. GRB 200514B: GROWTH-India follow-up of ZTF20aazpphd (AT2020jww)
  35. GRB200514B: ATLAS detections of ZTF20aazpphd
  36. GRB200514B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 611140062)
  37. GRB 200514B: Fermi GBM Final Real-time Localization
  38. Fermi GBM Sub-Threshold Detection of GRB 200512A
  39. Fermi-LAT Gamma-ray Observations of IceCube-200512A
  40. IceCube-200512A: not observable by Fermi-GBM
  41. GRB 200510A: AstroSat CZTI detection
  42. IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT
  43. GRB 200510A: BALROG localization (Fermi Trigger 610800081 / GRB 200510445)
  44. GRB 200510A: Fermi GBM Final Real-time Localization
  45. GRB 200509C: Fermi GBM Final Real-time Localization
  46. GRB 200509B: Fermi GBM Final Real-time Localization
  47. GRB 200507A: Fermi GBM Final Real-time Localization
  48. GRB 200506A: AstroSat CZTI detection
  49. GRB 200506C: AstroSat CZTI detection
  50. GRB 200505A: AGILE detection
  51. GRB 200506C: Fermi GBM Final Real-time Localization
  52. GRB 200506B: Fermi GBM Final Real-time Localization
  53. GRB 200506A: Fermi GBM Final Real-time Localization
  54. GRB 200505A: Fermi GBM Final Real-time Localization
  55. Insight-HXMT detection of a short bright burst from SGR 1935+2154
  56. GRB 200502A: AstroSat CZTI detection
  57. GRB 200502A: AGILE observations
  58. GRB 200503B: BALROG localization (Fermi Trigger 610219118 / GRB 200503721)
  59. GRB 200503B: Fermi GBM Final Real-time Localization
  60. GRB 200502A: Fermi GBM Final Real-time Localization
  61. Fermi GBM observation of a flare from the magnetar SGR 1806-20
  62. GRB 200501A: Fermi GBM Final Real-time Localization
  63. Fermi GBM trigger 200429866/609886052 is not a GRB
  64. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  65. A Forest of Bursts from SGR 1935+2154
  66. high bursting activity of SGR 1935+2154: CGBM observations
  67. SGR 1935+2154 the Insight-HXMT observation plan
  68. Fermi GBM observation of a bright flare from magnetar SGR 1935+2154
  69. IceCube-200425A: Upper limits from Fermi-GBM Observations
  70. Fermi-LAT Gamma-ray Observations of IceCube-200425A
  71. Gagarin-day GRB 200412B: observations with the 3.6m Devasthal Optical Telescope
  72. IceCube-200425A - IceCube observation of a high-energy neutrino candidate event
  73. IPN triangulation of GRB 200423A (short)
  74. GRB 200425B: Fermi GBM Final Real-time Localization
  75. Fermi GRB 200423A: Global MASTER-Net observations report
  76. GRB 200423A: Fermi GBM Final Real-time Localization
  77. GRB 200415A (possible magnetar Giant Flare in Sculptor Galaxy): INTEGRAL observations
  78. IPN Triangulation of a bright burst from SGR 1935+2154
  79. bright SGR burst detected by CALET Gamma-Ray Burst Monitor
  80. Fermi-LAT Gamma-ray Observations of IceCube-200421A
  81. Fermi GRB 200421A: Global MASTER-Net observations report
  82. GRB 200421A: Fermi GBM Final Real-time Localization
  83. IceCube-200421A: not observable by Fermi-GBM
  84. IceCube-200421A - IceCube observation of a high-energy neutrino candidate event
  85. GRB 200412B: continued Mondy and Terskol optical observations
  86. GRB 200420: Fermi GBM Final Localization Correction
  87. Fermi GRB 200420A: Global MASTER-Net observations report
  88. GRB 200420A: Fermi GBM Final Real-time Localization
  89. Fermi trigger No 608935505: Global MASTER-Net observations report
  90. GRB 200412B: continued Terskol optical observations
  91. GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
  92. GRB200412B: GROWTH India detection of afterglow
  93. GRB 200415A: Fermi-LAT localization update
  94. Konus-Wind observation of GRB 200415A (a magnetar Giant Flare in Sculptor Galaxy?)
  95. Improved IPN error box for GRB 200415A (consistent with the Sculptor Galaxy)
  96. GRB 200412B: continued Tautenburg observations
  97. GRB 200416A: Fermi GBM observation
  98. Fermi GRB 200415A: Global MASTER-Net observations report
  99. GRB 200411A: Chandra observations indicative of temporal steepening
  100. GRB 200412A : AstroSat CZTI detection

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