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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"

11103 results found.

  1. GRB 200412B: Fermi-LAT detection
  2. GRB 200412B: MASTER Optical Couterpart in Gagarin day!
  3. Konus-Wind observation of a bright burst from SGR 1935+2154
  4. GRB 200412B: Tiled Swift observations
  5. GRB 200412A: Fermi GBM detection
  6. Fermi GRB 200412B: Global MASTER-Net observations report
  7. GRB 200412B: BALROG localization (Fermi Trigger 608375325 / GRB 200412381)
  8. GRB 200412B: Fermi GBM Final Real-time Localization
  9. GRB 200412A: BALROG localization (Fermi Trigger 608367436 / GRB 200412290)
  10. Fermi-LAT Gamma-ray Observations of IceCube-200410A
  11. GRB 200411A: Fermi GBM observation
  12. IceCube-200410A: Upper limits from Fermi-GBM Observations
  13. GRB 200411A: Fermi GBM Final Real-time Localization
  14. IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
  15. SGR 1935+2154: Fermi GBM observation
  16. Fermi trigger No 608204639: Global MASTER-Net observations report
  17. IPN Triangulation of a bright burst from SGR 1935+2154
  18. Konus-Wind observation of GRB 200327A
  19. Fermi GBM Sub-Threshold Detection of GRB 200409A
  20. Fermi GRB 200407A: Global MASTER-Net observations report
  21. Fermi GRB 200407B: Global MASTER-Net observations report
  22. IPN triangulation of GRB 200407A (short)
  23. GRB 200407B: Fermi GBM Final Real-time Localization
  24. GRB 200407A: Fermi GBM Final Real-time Localization
  25. Fermi GRB 200405A: Global MASTER-Net observations report
  26. GRB 200405A: Fermi GBM Final Real-time Localization
  27. GRB 200404A: Fermi GBM Final Localization
  28. Fermi GRB 200403C: Global MASTER-Net observations report
  29. GRB 200404A: BALROG localization (Fermi Trigger 607712227 / GRB 200404706)
  30. GRB 200403A: AstroSat CZTI detection
  31. Fermi GRB 200403B: Global MASTER-Net observations report
  32. Fermi GRB 200403A: Global MASTER-Net observations report
  33. GRB 200403C: Fermi GBM Final Real-time Localization
  34. GRB 200403B: Fermi GBM Final Real-time Localization
  35. GRB 200403A: Fermi GBM Final Real-time Localization
  36. GRB 200325B: Mondy continued observations
  37. Fermi GRB 200402C: Global MASTER-Net observations report
  38. GRB 200402C: Fermi GBM Final Localization
  39. GRB 200402B: Fermi GBM Final Localization
  40. Fermi trigger No 607537834: Global MASTER-Net observations report
  41. GRB 200402B: BALROG localization (Fermi Trigger 607537834 / GRB 200402688)
  42. Fermi GRB 200402A: Global MASTER-Net observations report
  43. GRB 200402A: BALROG localization (Fermi Trigger 607513182 / GRB 200402403)
  44. GRB 200325B: Optical upper limit
  45. GRB 200402A: Fermi GBM Final Real-time Localization
  46. GRB 200325B: further Swift-XRT observations
  47. Fermi GRB 200401A: Global MASTER-Net observations report
  48. GRB 200401A: Fermi GBM Final Real-time Localization
  49. GRB 200325B: Mondy continued observations
  50. GRB 200325B: Mondy continued observations
  51. GRB 200327A: Fermi GBM detection
  52. GRB 200325B: Mondy continued observations
  53. GRB 200325B: Tautenburg observations
  54. IPN triangulation of GRB 200327A (short)
  55. GRB 200327A: AGILE/MCAL observations
  56. GRB 200325B: Fermi GBM observation
  57. Fermi trigger No 607035413: Global MASTER-Net observations report
  58. GRB 200327A: Fermi GBM Final Real-time Localization
  59. GRB 200325B: Swift-XRT and UVOT observations
  60. GRB 200325B: LCO Optical Detection
  61. GRB 200325B: Mondy, CrAO, AbAO afterglow confirmation and refined photometry of MASTER OT J111012.51+274912.8
  62. GRB 200325A: Fermi GBM observation
  63. GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
  64. Fermi trigger No 606918292: Global MASTER-Net observations report
  65. GRB 200325B: Swift ToO observations
  66. IPN triangulation of GRB 200325A (short)
  67. Fermi trigger No 606799116: Global MASTER-Net observations report
  68. GRB 200326A: Fermi GBM Final Real-time Localization
  69. GRB 200325B: MASTERt OT detection
  70. GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
  71. Fermi trigger No 606840801: Global MASTER-Net observations report
  72. GRB 200325B: Fermi GBM Final Real-time Localization
  73. GRB 200325A: AstroSat CZTI detection
  74. GRB 200325A: AGILE/MCAL observations
  75. GRB 200325A: Fermi GBM Final Real-time Localization
  76. GRB 200318A : AstroSat CZTI detection
  77. GRB 200317A: AstroSat CZTI detection
  78. Fermi trigger No 606681997: Global MASTER-Net observations report
  79. GRB 200323A: Fermi GBM detection
  80. GRB 200323A: Fermi GBM Final Real-time Localization
  81. Fermi trigger No 606614927: Global MASTER-Net observations report
  82. GRB 200320A: Fermi GBM Final Localization
  83. GRB 200319A: BALROG localization (Fermi Trigger 606296685 / GRB 200319323)
  84. GRB 200319A: Fermi GBM Final Real-time Localization
  85. Fermi trigger No 606263732: Global MASTER-Net observations report
  86. GRB 200318A: Fermi GBM Final Real-time Localization
  87. Konus-Wind observation of GRB 200313B
  88. LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
  89. Konus-Wind observation of GRB 200313A
  90. Konus-Wind observation of GRB 200311A
  91. LIGO/Virgo S200316bj: Upper limits from Fermi-GBM Observations
  92. Fermi trigger No 606098435: Global MASTER-Net observations report
  93. GRB 200317A: Fermi GBM Final Real-time Localization
  94. IPN triangulation of GRB 200313B (short)
  95. IPN triangulation of GRB 200313A
  96. GRB 200313A: Fermi GBM detection
  97. IPN triangulation of GRB 200311A
  98. Fermi trigger No 605789837: Global MASTER-Net observations report
  99. GRB 200313B: Fermi GBM Final Real-time Localization
  100. GRB 200313A: BALROG localization (Fermi Trigger 605756501 / GRB 200313071)

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