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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"

28238 results found.

  1. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  2. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  3. Swift GRB260113.43: Global MASTER-Net observations report
  4. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  5. EP260110a: TRT optical upper limits
  6. Konus-Wind detection of GRB 260101A
  7. GRB 260111A: Swift-XRT observations
  8. Swift Trigger 1439093: is probably not GRB 260113A
  9. GRB 260111A: COLIBRÍ optical afterglow candidate
  10. GRB 260111A: Fermi GBM Observation
  11. GRB 251230A: Mondy Optical Observations
  12. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  13. IceCube Alert 260111A: Global MASTER-Net observations report
  14. EP260110a: Global MASTER-Net observations report
  15. Fermi GRB 260111A: Global MASTER-Net observations report
  16. Swift trigger 1436759 is not an astrophysical event
  17. EP260110a: KAIT optical upper limit
  18. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  19. EP 260110a: COLIBRÍ optical observations
  20. EP260110a: SVOM/C-GFT upper limit
  21. EP260110a: Einstein Probe detection of an X-ray transient
  22. GRB 260109C: LCO optical upper limits
  23. GRB 260109C: Kilonova-Catcher optical upper limit
  24. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  25. Swift Trigger 1434591: possible GRB 260109C
  26. GRB 260102A: Swift-XRT afterglow detection
  27. GRB 260104A: Swift-BAT refined analysis
  28. GRB 260101A: Swift-BAT refined analysis
  29. Swift GRB 251230A: Global MASTER-Net OT detection
  30. Fermi GRB 260107A: Global MASTER-Net observations report
  31. GRB 260102A: AbAO optical observations
  32. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  33. Fermi GRB 260105A: Global MASTER-Net observations report
  34. GRB 260105B: Fermi GBM Detection
  35. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  36. GRB 260105A: SVOM/GRM observation
  37. GRB 260105B: SVOM/GRM observation
  38. FRB 20251229A: COLIBRÍ optical upper limits
  39. Fermi GRB 260105B: Global MASTER-Net observations report
  40. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  41. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  42. EP260105a: LCO Optical Upper limit
  43. EP260104a: Global MASTER-Net observations report
  44. EP260104a: Einstein Probe detection of a fast X-ray transient
  45. GRB 260101A: COLIBRÍ optical upper limits
  46. EP260105a: Global MASTER-Net observations report
  47. EP260105a: Einstein Probe detection of an X-ray transient
  48. GRB 260104A: COLIBRÍ optical upper limits
  49. Fermi GRB 260104B: Global MASTER-Net observations report
  50. Swift GRB 260104A: Global MASTER-Net observations report
  51. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  52. GRB 260104A: Swift-XRT refined Analysis
  53. GRB 260104A: Enhanced Swift-XRT position
  54. GRB 260101A: Swift/UVOT Detection
  55. GRB 260103A: GECAM-B observation of a burst
  56. GRB 260104A: Swift detection of a burst
  57. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  58. GRB 260101A: COLIBRÍ optical observations
  59. SVOM GRB260103.08: Global MASTER-Net observations report
  60. SVOM GRB260102A: Global MASTER-Net observations report
  61. Fermi GBM Sub-Threshold Detection of GRB 260102A
  62. GRB 260102A: EP-FXT follow-up observation
  63. EP260101a: Global MASTER-Net observations report
  64. GRB 260102A: LCO optical upper limits
  65. GRB 260102A: Swift-XRT observations
  66. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  67. GRB 260101A: Fermi GBM Observation
  68. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  69. GRB 260102A: SVOM detection of a burst
  70. GRB 260101A: NOT spectroscopic observations
  71. GRB 260101A: SVOM/GRM observation
  72. GRB 260101A: Swift-XRT refined Analysis
  73. Swift GRB 260101A: Global MASTER-Net observations report
  74. GRB 260101A: Enhanced Swift-XRT position
  75. EP260101a: Einstein Probe detection of an X-ray transient
  76. GRB 260101A: LCO detection of the optical counterpart
  77. GRB 260101A: Swift detection of a burst with an optical counterpart
  78. GRB 260101A: Fermi GBM Final Real-time Localization
  79. SVOM GRB251231.57: Global MASTER-Net observations report
  80. GRB 251230A: GRANDMA/TAROT Early Detection
  81. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  82. EP251229a: Optical upper limit with Kinder observations
  83. GRB 251230A: 1.3m DFOT optical upper limit
  84. GRB 251230A: Swift-XRT refined Analysis
  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. GRB251230A: 7DT optical upper limits
  89. GRB 251230A: GOTO optical upper limit
  90. EP251229a: NOT optical upper limits
  91. GRB 251230A / EP251230a: SVOM/VT optical observation
  92. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  93. GRB 251230A: Enhanced Swift-XRT position
  94. GRB 251230A: Early optical counterpart detection by LCO.
  95. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  96. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  97. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  98. Swift GRB 251230A: Global MASTER-Net observations report
  99. EP251229a: Global MASTER-Net observations report
  100. EP251229a: Einstein Probe detection of an X-ray transient

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