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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"

45720 results found.

  1. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  2. Swift Trigger 1434591: possible GRB 260109C
  3. GRB 260109B: Fermi GBM Final Real-time Localization
  4. GRB 260102A: Swift-XRT afterglow detection
  5. GRB 260109A: Fermi GBM Final Real-time Localization
  6. GRB 260104A: Swift-BAT refined analysis
  7. GRB 260101A: Swift-BAT refined analysis
  8. Swift GRB 251230A: Global MASTER-Net OT detection
  9. Fermi GRB 260107A: Global MASTER-Net observations report
  10. GRB 260102A: AbAO optical observations
  11. GRB 260107A: Fermi GBM Final Real-time Localization
  12. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  13. The EP-WXT trigger 01709251112 is likely a flaring star
  14. Fermi GRB 260105A: Global MASTER-Net observations report
  15. GRB 260105B: Fermi GBM Detection
  16. EP260105a: FTW optical observations
  17. EP260104a: FTW optical observations
  18. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  19. GRB 260105A: SVOM/GRM observation
  20. GRB 260105B: SVOM/GRM observation
  21. The EP-WXT trigger 01709251028 is likely a flaring star
  22. FRB 20251229A: COLIBRÍ optical upper limits
  23. Fermi GRB 260105B: Global MASTER-Net observations report
  24. EP260105a: SVOM/VT optical upperlimit
  25. GRB 260105B: Fermi GBM Final Real-time Localization
  26. GRB 260105A: Fermi GBM Final Real-time Localization
  27. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  28. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  29. EP260105a: LCO Optical Upper limit
  30. EP260104a: Global MASTER-Net observations report
  31. EP260104a: Einstein Probe detection of a fast X-ray transient
  32. GRB 260101A: COLIBRÍ optical upper limits
  33. EP260105a: Global MASTER-Net observations report
  34. EP260105a: Einstein Probe detection of an X-ray transient
  35. GRB 260103A: Insight-HXMT/HE detection
  36. GRB 260104A: COLIBRÍ optical upper limits
  37. GRB 260104C: Fermi GBM Final Real-time Localization
  38. Fermi GRB 260104B: Global MASTER-Net observations report
  39. Swift GRB 260104A: Global MASTER-Net observations report
  40. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  41. GRB 260104A: Swift-XRT refined Analysis
  42. GRB 260104A: Enhanced Swift-XRT position
  43. GRB 260101A: Swift/UVOT Detection
  44. GRB 260103A: GECAM-B observation of a burst
  45. GRB 260104B: Fermi GBM Final Localization
  46. GRB 260104A: Swift detection of a burst
  47. GRB 260103A: SVOM/GRM observation of a possible GRB
  48. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  49. GRB 260101A: COLIBRÍ optical observations
  50. SVOM GRB260103.08: Global MASTER-Net observations report
  51. GRB 260102B: Fermi GBM Final Real-time Localization
  52. SVOM GRB260102A: Global MASTER-Net observations report
  53. Fermi GBM Sub-Threshold Detection of GRB 260102A
  54. GRB 260102A: EP-FXT follow-up observation
  55. EP260101a: Global MASTER-Net observations report
  56. GRB 260102A: LCO optical upper limits
  57. GRB 260102A: Swift-XRT observations
  58. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  59. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  60. GRB 251230A / EP251230a: GECAM-B detection
  61. GRB 260102A: SVOM/VT optical counterpart
  62. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  63. GRB 260102A: Swift ToO observations
  64. GRB 260101A: Fermi GBM Observation
  65. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  66. GRB 260102A: SVOM detection of a burst
  67. GRB 260101A: GECAM-B detection
  68. GRB 260101A: NOT spectroscopic observations
  69. GRB 260101A: SVOM/GRM observation
  70. GRB 260101A: Swift-XRT refined Analysis
  71. Swift GRB 260101A: Global MASTER-Net observations report
  72. GRB 260101A: Enhanced Swift-XRT position
  73. EP260101a: Einstein Probe detection of an X-ray transient
  74. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  75. GRB 260101A: LCO detection of the optical counterpart
  76. GRB 260101A: Swift detection of a burst with an optical counterpart
  77. GRB 260101A: Fermi GBM Final Real-time Localization
  78. SVOM GRB251231.57: Global MASTER-Net observations report
  79. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  80. GRB 251230A: GRANDMA/TAROT Early Detection
  81. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  82. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  83. EP251229a: Optical upper limit with Kinder observations
  84. GRB 251230A: 1.3m DFOT optical upper limit
  85. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  86. GRB 251230A: Swift-XRT refined Analysis
  87. GRB 251231A: Fermi GBM Final Real-time Localization
  88. GRB 251222A: Mondy Optical Observations
  89. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  90. GRB 251230A: Swift/UVOT detection
  91. GRB251230A: 7DT optical upper limits
  92. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  93. EP251229a: BOOTES-2 early optical upper limit
  94. GRB 251230A: GOTO optical upper limit
  95. EP251229a: NOT optical upper limits
  96. GRB 251230A / EP251230a: SVOM/VT optical observation
  97. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  98. GRB 251230A: Enhanced Swift-XRT position
  99. GRB 251230A: Early optical counterpart detection by LCO.
  100. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up

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