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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"

20506 results found.

  1. GRB 260114A: NOT optical observations
  2. GRB 260114A: SVOM/GRM observation of a short burst
  3. GRB 260114A: Mondy optical observations
  4. GRB 260114A: GMG Optical Observation
  5. GRB 260114A: Swift detection of a short burst
  6. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  7. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  8. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  9. EP260110a: TRT optical upper limits
  10. Swift Trigger 1439093: is probably not GRB 260113A
  11. GRB 260111A: COLIBRÍ optical afterglow candidate
  12. GRB 251230A: Mondy Optical Observations
  13. Swift trigger 1436759 is not an astrophysical event
  14. EP260110a: KAIT optical upper limit
  15. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  16. EP 260110a: COLIBRÍ optical observations
  17. EP260110a: SVOM/C-GFT 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. Swift Trigger 1434591: possible GRB 260109C
  22. GRB 260102A: Swift-XRT afterglow detection
  23. GRB 260102A: AbAO optical observations
  24. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  25. Fermi GRB 260105A: Global MASTER-Net observations report
  26. GRB 260105A: SVOM/GRM observation
  27. GRB 260105B: SVOM/GRM observation
  28. FRB 20251229A: COLIBRÍ optical upper limits
  29. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  30. EP260105a: LCO Optical Upper limit
  31. EP260104a: Einstein Probe detection of a fast X-ray transient
  32. GRB 260101A: COLIBRÍ optical upper limits
  33. EP260105a: Einstein Probe detection of an X-ray transient
  34. GRB 260104A: COLIBRÍ optical upper limits
  35. GRB 260104C: Fermi GBM Final Real-time Localization
  36. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  37. GRB 260104A: Enhanced Swift-XRT position
  38. GRB 260101A: Swift/UVOT Detection
  39. GRB 260104A: Swift detection of a burst
  40. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  41. GRB 260101A: COLIBRÍ optical observations
  42. GRB 260102A: LCO optical upper limits
  43. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  44. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  45. GRB 260102A: SVOM detection of a burst
  46. GRB 260101A: NOT spectroscopic observations
  47. GRB 260101A: SVOM/GRM observation
  48. GRB 260101A: Enhanced Swift-XRT position
  49. EP260101a: Einstein Probe detection of an X-ray transient
  50. GRB 260101A: LCO detection of the optical counterpart
  51. GRB 260101A: Swift detection of a burst with an optical counterpart
  52. GRB 251230A: GRANDMA/TAROT Early Detection
  53. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  54. EP251229a: Optical upper limit with Kinder observations
  55. GRB 251230A: 1.3m DFOT optical upper limit
  56. GRB 251222A: Mondy Optical Observations
  57. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  58. GRB 251230A: Swift/UVOT detection
  59. GRB251230A: 7DT optical upper limits
  60. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  61. GRB 251230A: GOTO optical upper limit
  62. EP251229a: NOT optical upper limits
  63. GRB 251230A / EP251230a: SVOM/VT optical observation
  64. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  65. GRB 251230A: Enhanced Swift-XRT position
  66. GRB 251230A: Early optical counterpart detection by LCO.
  67. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  68. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  69. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  70. EP251229a: Einstein Probe detection of an X-ray transient
  71. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  72. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  73. GRB 251226A: SVOM/GRM observation
  74. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 251222A/EP251222b: Optical detection with Kinder observations
  76. EP251222a: Optical upper limit with Kinder observations
  77. GRB 251205A: Kilonova-Catcher optical afterglow detection
  78. GRB 251222A: AbAO optical observations
  79. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  80. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  81. GRB 251222A: ZTSH BVRI optical observations
  82. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  83. GRB 251222A: Continued 1.3m DFOT optical observation
  84. EP251220a: 3.6m DOT optical afterglow detection
  85. EP251220a: CrAO ZTSh optical observations
  86. EP251221a: PRIME upper limit
  87. EP251221a: Liverpool Telescope upper limits
  88. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  89. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  90. GRB 251222A: Swift-XRT afterglow detection
  91. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  92. EP251222a: NTT/ULTRACAM optical observations
  93. GRB 251222A / EP251222b: GOTO optical counterpart detection
  94. GRB 251222A / EP251222b: LCO optical observations
  95. GRB 251222A: 1.3m DFOT optical detection
  96. GRB251221A: 7DT optical upper limits
  97. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  98. EP251222a: Einstein Probe detection of an X-ray transient
  99. GRB 251222A: PRIME near-infrared detection
  100. EP251221a: NOT optical upper limit

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