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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"

23446 results found.

  1. GRB 260114A: 6 GHz VLA observations
  2. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  3. GRB 260114A : MITSuME Akeno optical upper limits
  4. GRB 260114A: COLIBRÍ optical upper limits
  5. GRB 260114A: TNG NIR upper limit
  6. GRB 260114A: NOT optical observations
  7. GRB 260114A: SVOM/GRM observation of a short burst
  8. GRB 260114A: Mondy optical observations
  9. GRB 260114A: GMG Optical Observation
  10. GRB 260114A: Swift detection of a short burst
  11. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  12. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  13. EP260110a: TRT optical upper limits
  14. Konus-Wind detection of GRB 260101A
  15. GRB 260111A: Swift-XRT observations
  16. Swift Trigger 1439093: is probably not GRB 260113A
  17. GRB 260111A: COLIBRÍ optical afterglow candidate
  18. GRB 251230A: Mondy Optical Observations
  19. EP260110a: SVOM/VT optical upper limits
  20. Swift trigger 1436759 is not an astrophysical event
  21. EP260110a: KAIT optical upper limit
  22. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  23. EP 260110a: COLIBRÍ optical observations
  24. EP260110a: SVOM/C-GFT upper limit
  25. EP260110a: Einstein Probe detection of an X-ray transient
  26. GRB 260109C: LCO optical upper limits
  27. GRB 260109C: Kilonova-Catcher optical upper limit
  28. Swift Trigger 1434591: possible GRB 260109C
  29. GRB 260102A: Swift-XRT afterglow detection
  30. GRB 260102A: AbAO optical observations
  31. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  32. EP260105a: FTW optical observations
  33. EP260104a: FTW optical observations
  34. GRB 260105A: SVOM/GRM observation
  35. GRB 260105B: SVOM/GRM observation
  36. FRB 20251229A: COLIBRÍ optical upper limits
  37. EP260105a: SVOM/VT optical upperlimit
  38. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  39. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  40. EP260105a: LCO Optical Upper limit
  41. EP260104a: Einstein Probe detection of a fast X-ray transient
  42. GRB 260101A: COLIBRÍ optical upper limits
  43. EP260105a: Einstein Probe detection of an X-ray transient
  44. GRB 260104A: COLIBRÍ optical upper limits
  45. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  46. GRB 260104A: Swift-XRT refined Analysis
  47. GRB 260104A: Enhanced Swift-XRT position
  48. GRB 260101A: Swift/UVOT Detection
  49. GRB 260104A: Swift detection of a burst
  50. GRB 260101A: COLIBRÍ optical observations
  51. GRB 260102A: LCO optical upper limits
  52. GRB 260102A: Swift-XRT observations
  53. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  54. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  55. GRB 260102A: SVOM detection of a burst
  56. GRB 260101A: SVOM/GRM observation
  57. GRB 260101A: Swift-XRT refined Analysis
  58. GRB 260101A: Enhanced Swift-XRT position
  59. EP260101a: Einstein Probe detection of an X-ray transient
  60. GRB 260101A: LCO detection of the optical counterpart
  61. GRB 260101A: Swift detection of a burst with an optical counterpart
  62. GRB 251230A: GRANDMA/TAROT Early Detection
  63. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  64. EP251229a: Optical upper limit with Kinder observations
  65. GRB 251230A: 1.3m DFOT optical upper limit
  66. GRB 251230A: Swift-XRT refined Analysis
  67. GRB 251222A: Mondy Optical Observations
  68. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  69. GRB 251230A: Swift/UVOT detection
  70. GRB251230A: 7DT optical upper limits
  71. GRB 251230A: GOTO optical upper limit
  72. EP251229a: NOT optical upper limits
  73. GRB 251230A / EP251230a: SVOM/VT optical observation
  74. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  75. GRB 251230A: Enhanced Swift-XRT position
  76. GRB 251230A: Early optical counterpart detection by LCO.
  77. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  78. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  79. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  80. EP251229a: Einstein Probe detection of an X-ray transient
  81. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  82. GRB 251226A: Glowbug gamma-ray detection
  83. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  84. GRB 251226A: SVOM/GRM observation
  85. GRB 251222A/EP251222b: Optical detection with Kinder observations
  86. EP251222a: Optical upper limit with Kinder observations
  87. GRB 251205A: Kilonova-Catcher optical afterglow detection
  88. GRB 251222A: AbAO optical observations
  89. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  90. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  91. GRB 251222A: ZTSH BVRI optical observations
  92. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  93. GRB 251222A: Continued 1.3m DFOT optical observation
  94. EP251220a: 3.6m DOT optical afterglow detection
  95. EP251220a: CrAO ZTSh optical observations
  96. EP251221a: PRIME upper limit
  97. EP251221a: Liverpool Telescope upper limits
  98. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  99. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  100. GRB 251222A: Swift-XRT afterglow detection

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