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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"

45558 results found.

  1. GRB 260112B: Fermi GBM Final Real-time Localization
  2. GRB 260111A: Swift ToO observations
  3. GRB 251230A: Mondy Optical Observations
  4. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  5. GRB 260112A: Fermi GBM Final Real-time Localization
  6. EP260110a: SVOM/VT optical upper limits
  7. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  8. IceCube Alert 260111A: Global MASTER-Net observations report
  9. EP260110a: Global MASTER-Net observations report
  10. Fermi GRB 260111A: Global MASTER-Net observations report
  11. GRB 260111A: Fermi GBM Final Real-time Localization
  12. Swift trigger 1436759 is not an astrophysical event
  13. EP260110a: KAIT optical upper limit
  14. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  15. EP 260110a: COLIBRÍ optical observations
  16. EP260110a: SVOM/C-GFT upper limit
  17. EP260110a: BOOTES-5/JGU optical upper limit
  18. EP260110a: Einstein Probe detection of an X-ray transient
  19. GRB 260109C: LCO optical upper limits
  20. GRB 260109C: Kilonova-Catcher optical upper limit
  21. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  22. Swift Trigger 1434591: possible GRB 260109C
  23. GRB 260109B: Fermi GBM Final Real-time Localization
  24. GRB 260102A: Swift-XRT afterglow detection
  25. GRB 260109A: Fermi GBM Final Real-time Localization
  26. GRB 260104A: Swift-BAT refined analysis
  27. GRB 260101A: Swift-BAT refined analysis
  28. Swift GRB 251230A: Global MASTER-Net OT detection
  29. Fermi GRB 260107A: Global MASTER-Net observations report
  30. GRB 260102A: AbAO optical observations
  31. GRB 260107A: Fermi GBM Final Real-time Localization
  32. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  33. The EP-WXT trigger 01709251112 is likely a flaring star
  34. Fermi GRB 260105A: Global MASTER-Net observations report
  35. GRB 260105B: Fermi GBM Detection
  36. EP260105a: FTW optical observations
  37. EP260104a: FTW optical observations
  38. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  39. GRB 260105A: SVOM/GRM observation
  40. GRB 260105B: SVOM/GRM observation
  41. The EP-WXT trigger 01709251028 is likely a flaring star
  42. FRB 20251229A: COLIBRÍ optical upper limits
  43. Fermi GRB 260105B: Global MASTER-Net observations report
  44. EP260105a: SVOM/VT optical upperlimit
  45. GRB 260105B: Fermi GBM Final Real-time Localization
  46. GRB 260105A: Fermi GBM Final Real-time Localization
  47. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  48. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  49. EP260105a: LCO Optical Upper limit
  50. EP260104a: Global MASTER-Net observations report
  51. EP260104a: Einstein Probe detection of a fast X-ray transient
  52. GRB 260101A: COLIBRÍ optical upper limits
  53. EP260105a: Global MASTER-Net observations report
  54. EP260105a: Einstein Probe detection of an X-ray transient
  55. GRB 260103A: Insight-HXMT/HE detection
  56. GRB 260104A: COLIBRÍ optical upper limits
  57. GRB 260104C: Fermi GBM Final Real-time Localization
  58. Fermi GRB 260104B: Global MASTER-Net observations report
  59. Swift GRB 260104A: Global MASTER-Net observations report
  60. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  61. GRB 260104A: Swift-XRT refined Analysis
  62. GRB 260104A: Enhanced Swift-XRT position
  63. GRB 260101A: Swift/UVOT Detection
  64. GRB 260103A: GECAM-B observation of a burst
  65. GRB 260104B: Fermi GBM Final Localization
  66. GRB 260104A: Swift detection of a burst
  67. GRB 260103A: SVOM/GRM observation of a possible GRB
  68. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  69. GRB 260101A: COLIBRÍ optical observations
  70. SVOM GRB260103.08: Global MASTER-Net observations report
  71. GRB 260102B: Fermi GBM Final Real-time Localization
  72. SVOM GRB260102A: Global MASTER-Net observations report
  73. Fermi GBM Sub-Threshold Detection of GRB 260102A
  74. GRB 260102A: EP-FXT follow-up observation
  75. EP260101a: Global MASTER-Net observations report
  76. GRB 260102A: LCO optical upper limits
  77. GRB 260102A: Swift-XRT observations
  78. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  79. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  80. GRB 251230A / EP251230a: GECAM-B detection
  81. GRB 260102A: SVOM/VT optical counterpart
  82. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  83. GRB 260102A: Swift ToO observations
  84. GRB 260101A: Fermi GBM Observation
  85. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  86. GRB 260102A: SVOM detection of a burst
  87. GRB 260101A: GECAM-B detection
  88. GRB 260101A: NOT spectroscopic observations
  89. GRB 260101A: SVOM/GRM observation
  90. GRB 260101A: Swift-XRT refined Analysis
  91. Swift GRB 260101A: Global MASTER-Net observations report
  92. GRB 260101A: Enhanced Swift-XRT position
  93. EP260101a: Einstein Probe detection of an X-ray transient
  94. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  95. GRB 260101A: LCO detection of the optical counterpart
  96. GRB 260101A: Swift detection of a burst with an optical counterpart
  97. GRB 260101A: Fermi GBM Final Real-time Localization
  98. SVOM GRB251231.57: Global MASTER-Net observations report
  99. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  100. GRB 251230A: GRANDMA/TAROT Early Detection

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