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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36143 results found.

  1. GRB 260114A: Fermi GBM Final Real-time Localization
  2. Konus-Wind detection of GRB 260101A
  3. GRB 260111A: Swift-XRT observations
  4. Swift Trigger 1439093: is probably not GRB 260113A
  5. GRB 260111A: COLIBRÍ optical afterglow candidate
  6. GRB 260111A: GECAM-B observation of a burst
  7. GRB 260111A: Fermi GBM Observation
  8. Swift Trigger 1434591 is not a GRB
  9. GRB 260111A: GOTO optical upper limits
  10. GRB 260112B: Fermi GBM Final Real-time Localization
  11. GRB 260111A: Swift ToO observations
  12. GRB 251230A: Mondy Optical Observations
  13. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  14. GRB 260112A: Fermi GBM Final Real-time Localization
  15. Fermi GRB 260111A: Global MASTER-Net observations report
  16. GRB 260111A: Fermi GBM Final Real-time Localization
  17. EP260110a: KAIT optical upper limit
  18. GRB 260109C: LCO optical upper limits
  19. GRB 260109C: Kilonova-Catcher optical upper limit
  20. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  21. Swift Trigger 1434591: possible GRB 260109C
  22. GRB 260109B: Fermi GBM Final Real-time Localization
  23. GRB 260102A: Swift-XRT afterglow detection
  24. GRB 260109A: Fermi GBM Final Real-time Localization
  25. GRB 260104A: Swift-BAT refined analysis
  26. GRB 260101A: Swift-BAT refined analysis
  27. Swift GRB 251230A: Global MASTER-Net OT detection
  28. Fermi GRB 260107A: Global MASTER-Net observations report
  29. GRB 260102A: AbAO optical observations
  30. GRB 260107A: Fermi GBM Final Real-time Localization
  31. Fermi GRB 260105A: Global MASTER-Net observations report
  32. GRB 260105B: Fermi GBM Detection
  33. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  34. GRB 260105A: SVOM/GRM observation
  35. GRB 260105B: SVOM/GRM observation
  36. Fermi GRB 260105B: Global MASTER-Net observations report
  37. GRB 260105B: Fermi GBM Final Real-time Localization
  38. GRB 260105A: Fermi GBM Final Real-time Localization
  39. GRB 260101A: COLIBRÍ optical upper limits
  40. GRB 260103A: Insight-HXMT/HE detection
  41. GRB 260104A: COLIBRÍ optical upper limits
  42. GRB 260104C: Fermi GBM Final Real-time Localization
  43. Fermi GRB 260104B: Global MASTER-Net observations report
  44. Swift GRB 260104A: Global MASTER-Net observations report
  45. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  46. GRB 260104A: Swift-XRT refined Analysis
  47. GRB 260104A: Enhanced Swift-XRT position
  48. GRB 260101A: Swift/UVOT Detection
  49. GRB 260103A: GECAM-B observation of a burst
  50. GRB 260104B: Fermi GBM Final Localization
  51. GRB 260104A: Swift detection of a burst
  52. GRB 260103A: SVOM/GRM observation of a possible GRB
  53. GRB 260101A: COLIBRÍ optical observations
  54. GRB 260102B: Fermi GBM Final Real-time Localization
  55. Fermi GBM Sub-Threshold Detection of GRB 260102A
  56. GRB 260102A: EP-FXT follow-up observation
  57. GRB 260102A: LCO optical upper limits
  58. GRB 260102A: Swift-XRT observations
  59. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  60. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  61. GRB 251230A / EP251230a: GECAM-B detection
  62. GRB 260102A: SVOM/VT optical counterpart
  63. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  64. GRB 260102A: Swift ToO observations
  65. GRB 260101A: Fermi GBM Observation
  66. GRB 260102A: SVOM detection of a burst
  67. GRB 260101A: GECAM-B detection
  68. GRB 260101A: NOT spectroscopic observations
  69. GRB 260101A: SVOM/GRM observation
  70. GRB 260101A: Swift-XRT refined Analysis
  71. Swift GRB 260101A: Global MASTER-Net observations report
  72. GRB 260101A: Enhanced Swift-XRT position
  73. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  74. GRB 260101A: LCO detection of the optical counterpart
  75. GRB 260101A: Swift detection of a burst with an optical counterpart
  76. GRB 260101A: Fermi GBM Final Real-time Localization
  77. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  78. GRB 251230A: GRANDMA/TAROT Early Detection
  79. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  80. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  81. GRB 251230A: 1.3m DFOT optical upper limit
  82. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  83. GRB 251230A: Swift-XRT refined Analysis
  84. GRB 251231A: Fermi GBM Final Real-time Localization
  85. GRB 251222A: Mondy Optical Observations
  86. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  87. GRB 251230A: Swift/UVOT detection
  88. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  89. GRB 251230A: GOTO optical upper limit
  90. GRB 251230A / EP251230a: SVOM/VT optical observation
  91. GRB 251230A: Enhanced Swift-XRT position
  92. GRB 251230A: Early optical counterpart detection by LCO.
  93. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  94. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  95. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  96. Swift GRB 251230A: Global MASTER-Net observations report
  97. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  98. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  99. GRB 251226A: Glowbug gamma-ray detection
  100. GRB 251222A/EP251222b: 1.6m Mephisto optical followup

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