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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"

28115 results found.

  1. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  2. Swift Trigger 1434591: possible GRB 260109C
  3. GRB 260102A: Swift-XRT afterglow detection
  4. GRB 260104A: Swift-BAT refined analysis
  5. GRB 260101A: Swift-BAT refined analysis
  6. Swift GRB 251230A: Global MASTER-Net OT detection
  7. Fermi GRB 260107A: Global MASTER-Net observations report
  8. GRB 260102A: AbAO optical observations
  9. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  10. Fermi GRB 260105A: Global MASTER-Net observations report
  11. GRB 260105B: Fermi GBM Detection
  12. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  13. GRB 260105A: SVOM/GRM observation
  14. GRB 260105B: SVOM/GRM observation
  15. FRB 20251229A: COLIBRÍ optical upper limits
  16. Fermi GRB 260105B: Global MASTER-Net observations report
  17. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  18. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  19. EP260105a: LCO Optical Upper limit
  20. EP260104a: Global MASTER-Net observations report
  21. EP260104a: Einstein Probe detection of a fast X-ray transient
  22. GRB 260101A: COLIBRÍ optical upper limits
  23. EP260105a: Global MASTER-Net observations report
  24. EP260105a: Einstein Probe detection of an X-ray transient
  25. GRB 260104A: COLIBRÍ optical upper limits
  26. Fermi GRB 260104B: Global MASTER-Net observations report
  27. Swift GRB 260104A: Global MASTER-Net observations report
  28. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  29. GRB 260104A: Swift-XRT refined Analysis
  30. GRB 260104A: Enhanced Swift-XRT position
  31. GRB 260101A: Swift/UVOT Detection
  32. GRB 260103A: GECAM-B observation of a burst
  33. GRB 260104A: Swift detection of a burst
  34. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  35. GRB 260101A: COLIBRÍ optical observations
  36. SVOM GRB260103.08: Global MASTER-Net observations report
  37. SVOM GRB260102A: Global MASTER-Net observations report
  38. Fermi GBM Sub-Threshold Detection of GRB 260102A
  39. GRB 260102A: EP-FXT follow-up observation
  40. EP260101a: Global MASTER-Net observations report
  41. GRB 260102A: LCO optical upper limits
  42. GRB 260102A: Swift-XRT observations
  43. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  44. GRB 260101A: Fermi GBM Observation
  45. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  46. GRB 260102A: SVOM detection of a burst
  47. GRB 260101A: NOT spectroscopic observations
  48. GRB 260101A: SVOM/GRM observation
  49. GRB 260101A: Swift-XRT refined Analysis
  50. Swift GRB 260101A: Global MASTER-Net observations report
  51. GRB 260101A: Enhanced Swift-XRT position
  52. EP260101a: Einstein Probe detection of an X-ray transient
  53. GRB 260101A: LCO detection of the optical counterpart
  54. GRB 260101A: Swift detection of a burst with an optical counterpart
  55. GRB 260101A: Fermi GBM Final Real-time Localization
  56. SVOM GRB251231.57: Global MASTER-Net observations report
  57. GRB 251230A: GRANDMA/TAROT Early Detection
  58. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  59. EP251229a: Optical upper limit with Kinder observations
  60. GRB 251230A: 1.3m DFOT optical upper limit
  61. GRB 251230A: Swift-XRT refined Analysis
  62. GRB 251222A: Mondy Optical Observations
  63. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  64. GRB 251230A: Swift/UVOT detection
  65. GRB251230A: 7DT optical upper limits
  66. GRB 251230A: GOTO optical upper limit
  67. EP251229a: NOT optical upper limits
  68. GRB 251230A / EP251230a: SVOM/VT optical observation
  69. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  70. GRB 251230A: Enhanced Swift-XRT position
  71. GRB 251230A: Early optical counterpart detection by LCO.
  72. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  73. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  74. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  75. Swift GRB 251230A: Global MASTER-Net observations report
  76. EP251229a: Global MASTER-Net observations report
  77. EP251229a: Einstein Probe detection of an X-ray transient
  78. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  79. GRB 251226A: Glowbug gamma-ray detection
  80. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  81. Fermi GRB 251228A: Global MASTER-Net observations report
  82. GRB 251226A: SVOM/GRM observation
  83. GRB 251226A: GECAM-B detection
  84. SVOM GRB251227.07: Global MASTER-Net observations report
  85. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  86. IceCube Alert 251225.84: Global MASTER-Net observations report
  87. GRB 251222A/EP251222b: Optical detection with Kinder observations
  88. EP251222a: Optical upper limit with Kinder observations
  89. GRB 251221A: Swift-BAT refined analysis
  90. GRB 251205A: Kilonova-Catcher optical afterglow detection
  91. GRB 251222A: AbAO optical observations
  92. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  93. GRB 251222A: ZTSH BVRI optical observations
  94. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  95. GRB 251222A: Continued 1.3m DFOT optical observation
  96. EP251220a: 3.6m DOT optical afterglow detection
  97. GRB 251222A: Fermi GBM Observation
  98. EP251220a: CrAO ZTSh optical observations
  99. EP251221a: PRIME upper limit
  100. EP251222a: Global MASTER-Net observations report

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