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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"

26553 results found.

  1. GRB 260112B: GECAM-B observation
  2. GRB 260114A: Swift detection of a short burst
  3. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  4. EP260110a: TRT optical upper limits
  5. Konus-Wind detection of GRB 260101A
  6. Swift Trigger 1439093: is probably not GRB 260113A
  7. GRB 260111A: COLIBRÍ optical afterglow candidate
  8. GRB 260111A: GECAM-B observation of a burst
  9. GRB 260111A: Fermi GBM Observation
  10. GRB 260111A: GOTO optical upper limits
  11. GRB 251230A: Mondy Optical Observations
  12. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  13. EP260110a: SVOM/VT optical upper limits
  14. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  15. EP260110a: KAIT optical upper limit
  16. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  17. EP 260110a: COLIBRÍ optical observations
  18. EP260110a: SVOM/C-GFT upper limit
  19. EP260110a: BOOTES-5/JGU optical upper limit
  20. EP260110a: Einstein Probe detection of an X-ray transient
  21. GRB 260109C: LCO optical upper limits
  22. GRB 260109C: Kilonova-Catcher optical upper limit
  23. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  24. Swift Trigger 1434591: possible GRB 260109C
  25. GRB 260102A: Swift-XRT afterglow detection
  26. GRB 260104A: Swift-BAT refined analysis
  27. GRB 260101A: Swift-BAT refined analysis
  28. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  29. GRB 260105B: Fermi GBM Detection
  30. EP260105a: FTW optical observations
  31. EP260104a: FTW optical observations
  32. GRB 260105A: SVOM/GRM observation
  33. GRB 260105B: SVOM/GRM observation
  34. FRB 20251229A: COLIBRÍ optical upper limits
  35. EP260105a: SVOM/VT optical upperlimit
  36. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  37. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  38. EP260105a: LCO Optical Upper limit
  39. EP260104a: Einstein Probe detection of a fast X-ray transient
  40. GRB 260101A: COLIBRÍ optical upper limits
  41. EP260105a: Einstein Probe detection of an X-ray transient
  42. GRB 260103A: Insight-HXMT/HE detection
  43. GRB 260104A: COLIBRÍ optical upper limits
  44. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  45. GRB 260104A: Enhanced Swift-XRT position
  46. GRB 260103A: GECAM-B observation of a burst
  47. GRB 260104A: Swift detection of a burst
  48. GRB 260103A: SVOM/GRM observation of a possible GRB
  49. GRB 260101A: COLIBRÍ optical observations
  50. SVOM GRB260103.08: Global MASTER-Net observations report
  51. SVOM GRB260102A: Global MASTER-Net observations report
  52. Fermi GBM Sub-Threshold Detection of GRB 260102A
  53. GRB 260102A: EP-FXT follow-up observation
  54. GRB 260102A: LCO optical upper limits
  55. GRB 260102A: Swift-XRT observations
  56. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  57. GRB 251230A / EP251230a: GECAM-B detection
  58. GRB 260102A: SVOM/VT optical counterpart
  59. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  60. GRB 260102A: Swift ToO observations
  61. GRB 260101A: Fermi GBM Observation
  62. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  63. GRB 260102A: SVOM detection of a burst
  64. GRB 260101A: GECAM-B detection
  65. GRB 260101A: NOT spectroscopic observations
  66. GRB 260101A: SVOM/GRM observation
  67. GRB 260101A: Enhanced Swift-XRT position
  68. EP260101a: Einstein Probe detection of an X-ray transient
  69. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  70. GRB 260101A: LCO detection of the optical counterpart
  71. GRB 260101A: Swift detection of a burst with an optical counterpart
  72. SVOM GRB251231.57: Global MASTER-Net observations report
  73. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  74. GRB 251230A: GRANDMA/TAROT Early Detection
  75. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  76. GRB 251230A: 1.3m DFOT optical upper limit
  77. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  78. GRB251230A: 7DT optical upper limits
  79. EP251229a: BOOTES-2 early optical upper limit
  80. GRB 251230A: GOTO optical upper limit
  81. GRB 251230A / EP251230a: SVOM/VT optical observation
  82. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  83. GRB 251230A: Enhanced Swift-XRT position
  84. GRB 251230A: Early optical counterpart detection by LCO.
  85. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  86. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  87. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  88. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  89. EP251229a: Einstein Probe detection of an X-ray transient
  90. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  91. GRB 251226A: Glowbug gamma-ray detection
  92. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  93. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  94. GRB 251226A: SVOM/GRM observation
  95. GRB 251226A: GECAM-B detection
  96. SVOM GRB251227.07: Global MASTER-Net observations report
  97. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  98. GRB 251222A: NUTTelA-TAO Early Measurements
  99. GRB 251222A/EP251222b: Optical detection with Kinder observations
  100. GRB 251221A: Swift-BAT refined analysis

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