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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"

28201 results found.

  1. GRB 260109A: Fermi GBM Final Real-time Localization
  2. Swift GRB 251230A: Global MASTER-Net OT detection
  3. GRB 260107A: Fermi GBM Final Real-time Localization
  4. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  5. GRB 260105B: Fermi GBM Detection
  6. EP260105a: FTW optical observations
  7. EP260104a: FTW optical observations
  8. GRB 260105B: Fermi GBM Final Real-time Localization
  9. GRB 260105A: Fermi GBM Final Real-time Localization
  10. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  11. EP260104a: Einstein Probe detection of a fast X-ray transient
  12. GRB 260101A: COLIBRÍ optical upper limits
  13. EP260105a: Einstein Probe detection of an X-ray transient
  14. GRB 260103A: Insight-HXMT/HE detection
  15. GRB 260104A: COLIBRÍ optical upper limits
  16. GRB 260104C: Fermi GBM Final Real-time Localization
  17. GRB 260104A: Swift-XRT refined Analysis
  18. GRB 260104A: Enhanced Swift-XRT position
  19. GRB 260101A: Swift/UVOT Detection
  20. GRB 260104B: Fermi GBM Final Localization
  21. GRB 260104A: Swift detection of a burst
  22. GRB 260101A: COLIBRÍ optical observations
  23. GRB 260102B: Fermi GBM Final Real-time Localization
  24. Fermi GBM Sub-Threshold Detection of GRB 260102A
  25. GRB 260102A: LCO optical upper limits
  26. GRB 260102A: Swift-XRT observations
  27. GRB 251230A / EP251230a: GECAM-B detection
  28. GRB 260102A: SVOM/VT optical counterpart
  29. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  30. GRB 260102A: Swift ToO observations
  31. GRB 260102A: SVOM detection of a burst
  32. GRB 260101A: GECAM-B detection
  33. GRB 260101A: NOT spectroscopic observations
  34. GRB 260101A: SVOM/GRM observation
  35. GRB 260101A: Swift-XRT refined Analysis
  36. GRB 260101A: Enhanced Swift-XRT position
  37. EP260101a: Einstein Probe detection of an X-ray transient
  38. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  39. GRB 260101A: LCO detection of the optical counterpart
  40. GRB 260101A: Swift detection of a burst with an optical counterpart
  41. GRB 260101A: Fermi GBM Final Real-time Localization
  42. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  43. GRB 251230A: GRANDMA/TAROT Early Detection
  44. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  45. EP251229a: Optical upper limit with Kinder observations
  46. GRB 251230A: 1.3m DFOT optical upper limit
  47. GRB 251230A: Swift-XRT refined Analysis
  48. GRB 251231A: Fermi GBM Final Real-time Localization
  49. GRB 251230A: Swift/UVOT detection
  50. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  51. EP251229a: BOOTES-2 early optical upper limit
  52. GRB 251230A: Enhanced Swift-XRT position
  53. GRB 251230A: Early optical counterpart detection by LCO.
  54. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  55. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  56. EP251229a: Einstein Probe detection of an X-ray transient
  57. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  58. GRB 251226A: Glowbug gamma-ray detection
  59. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  60. GRB 251228A: Fermi GBM Final Real-time Localization
  61. GRB 251226A: GECAM-B detection
  62. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  63. GRB 251222A/EP251222b: Optical detection with Kinder observations
  64. EP251222a: Optical upper limit with Kinder observations
  65. GRB 251205A: Kilonova-Catcher optical afterglow detection
  66. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  67. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  68. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  69. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  70. GRB 251222A: Continued 1.3m DFOT optical observation
  71. EP251220a: 3.6m DOT optical afterglow detection
  72. GRB 251222A: Fermi GBM Observation
  73. Konus-Wind detection of GRB 251222A / EP251222b
  74. GRB 251222A: Swift-XRT afterglow detection
  75. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  76. GRB 251222A / EP251222b: GOTO optical counterpart detection
  77. GRB 251222A: 1.3m DFOT optical detection
  78. GRB251221A: 7DT optical upper limits
  79. EP251222a: GSP Optical Counterpart Detection
  80. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  81. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  82. EP251222a: Einstein Probe detection of an X-ray transient
  83. GRB 251222A: PRIME near-infrared detection
  84. GRB 251222A: NOT optical observations
  85. IPN triangulation of GRB 251220B (short)
  86. GRB 251222A: Swift ToO observations
  87. GRB 251222A: SVOM detection of a long burst
  88. GRB 251222A: Fermi GBM Final Real-time Localization
  89. GRB 251221A: PRIME near-infrared observation
  90. GRB 251221A: UAFO and Mondy optical upper limit
  91. GRB 251221A: Swift-XRT refined Analysis
  92. EP251221a: Einstein Probe detection of a fast X-ray transient
  93. GRB 251221A: Swift/UVOT Upper Limits
  94. GRB 251221A: Enhanced Swift-XRT position
  95. GRB 251221B: Fermi GBM Final Real-time Localization
  96. EP251220a: EP-FXT follow-up observation
  97. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  98. EP 251220a: GOTO optical counterpart detection
  99. GRB 251221A: COLIBRÍ detection of the optical counterpart
  100. EP 251220a: COLIBRÍ detection of the optical counterpart

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