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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"

20502 results found.

  1. GRB 260114A: Swift detection of a short burst
  2. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  3. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  4. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  5. EP260110a: TRT optical upper limits
  6. Swift Trigger 1439093: is probably not GRB 260113A
  7. GRB 260111A: COLIBRÍ optical afterglow candidate
  8. GRB 251230A: Mondy Optical Observations
  9. Swift trigger 1436759 is not an astrophysical event
  10. EP260110a: KAIT optical upper limit
  11. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  12. EP 260110a: COLIBRÍ optical observations
  13. EP260110a: SVOM/C-GFT upper limit
  14. EP260110a: Einstein Probe detection of an X-ray transient
  15. GRB 260109C: LCO optical upper limits
  16. GRB 260109C: Kilonova-Catcher optical upper limit
  17. Swift Trigger 1434591: possible GRB 260109C
  18. GRB 260102A: Swift-XRT afterglow detection
  19. GRB 260102A: AbAO optical observations
  20. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  21. Fermi GRB 260105A: Global MASTER-Net observations report
  22. GRB 260105A: SVOM/GRM observation
  23. GRB 260105B: SVOM/GRM observation
  24. FRB 20251229A: COLIBRÍ optical upper limits
  25. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  26. EP260105a: LCO Optical Upper limit
  27. EP260104a: Einstein Probe detection of a fast X-ray transient
  28. GRB 260101A: COLIBRÍ optical upper limits
  29. EP260105a: Einstein Probe detection of an X-ray transient
  30. GRB 260104A: COLIBRÍ optical upper limits
  31. GRB 260104C: Fermi GBM Final Real-time Localization
  32. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  33. GRB 260104A: Enhanced Swift-XRT position
  34. GRB 260101A: Swift/UVOT Detection
  35. GRB 260104A: Swift detection of a burst
  36. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  37. GRB 260101A: COLIBRÍ optical observations
  38. GRB 260102A: LCO optical upper limits
  39. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  40. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  41. GRB 260102A: SVOM detection of a burst
  42. GRB 260101A: NOT spectroscopic observations
  43. GRB 260101A: SVOM/GRM observation
  44. GRB 260101A: Enhanced Swift-XRT position
  45. EP260101a: Einstein Probe detection of an X-ray transient
  46. GRB 260101A: LCO detection of the optical counterpart
  47. GRB 260101A: Swift detection of a burst with an optical counterpart
  48. GRB 251230A: GRANDMA/TAROT Early Detection
  49. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  50. EP251229a: Optical upper limit with Kinder observations
  51. GRB 251230A: 1.3m DFOT optical upper limit
  52. GRB 251222A: Mondy Optical Observations
  53. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  54. GRB 251230A: Swift/UVOT detection
  55. GRB251230A: 7DT optical upper limits
  56. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  57. GRB 251230A: GOTO optical upper limit
  58. EP251229a: NOT optical upper limits
  59. GRB 251230A / EP251230a: SVOM/VT optical observation
  60. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  61. GRB 251230A: Enhanced Swift-XRT position
  62. GRB 251230A: Early optical counterpart detection by LCO.
  63. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  64. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  65. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  66. EP251229a: Einstein Probe detection of an X-ray transient
  67. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  68. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  69. GRB 251226A: SVOM/GRM observation
  70. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 251222A/EP251222b: Optical detection with Kinder observations
  72. EP251222a: Optical upper limit with Kinder observations
  73. GRB 251205A: Kilonova-Catcher optical afterglow detection
  74. GRB 251222A: AbAO optical observations
  75. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  76. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  77. GRB 251222A: ZTSH BVRI optical observations
  78. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  79. GRB 251222A: Continued 1.3m DFOT optical observation
  80. EP251220a: 3.6m DOT optical afterglow detection
  81. EP251220a: CrAO ZTSh optical observations
  82. EP251221a: PRIME upper limit
  83. EP251221a: Liverpool Telescope upper limits
  84. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  85. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  86. GRB 251222A: Swift-XRT afterglow detection
  87. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  88. EP251222a: NTT/ULTRACAM optical observations
  89. GRB 251222A / EP251222b: GOTO optical counterpart detection
  90. GRB 251222A / EP251222b: LCO optical observations
  91. GRB 251222A: 1.3m DFOT optical detection
  92. GRB251221A: 7DT optical upper limits
  93. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  94. EP251222a: Einstein Probe detection of an X-ray transient
  95. GRB 251222A: PRIME near-infrared detection
  96. EP251221a: NOT optical upper limit
  97. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  98. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  99. IPN triangulation of GRB 251220B (short)
  100. GRB 251222A: SVOM/VT optical candidate

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