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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"

26566 results found.

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

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