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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"

32688 results found.

  1. GRB 260114A: Mondy optical observations
  2. GRB 260114A: Fermi GBM observation
  3. GRB 260112B: GECAM-B observation
  4. GRB 260114A: GMG Optical Observation
  5. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  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. Konus-Wind detection of GRB 260101A
  11. GRB 260111A: Swift-XRT observations
  12. GRB 260111A: COLIBRÍ optical afterglow candidate
  13. GRB 260111A: GECAM-B observation of a burst
  14. GRB 260111A: Fermi GBM Observation
  15. Swift Trigger 1434591 is not a GRB
  16. GRB 260111A: GOTO optical upper limits
  17. GRB 260111A: Swift ToO observations
  18. GRB 251230A: Mondy Optical Observations
  19. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  20. EP260110a: SVOM/VT optical upper limits
  21. EP260110a: Global MASTER-Net observations report
  22. Fermi GRB 260111A: Global MASTER-Net observations report
  23. EP260110a: KAIT optical upper limit
  24. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  25. EP 260110a: COLIBRÍ optical observations
  26. EP260110a: SVOM/C-GFT upper limit
  27. EP260110a: BOOTES-5/JGU optical upper limit
  28. GRB 260109C: LCO optical upper limits
  29. GRB 260109C: Kilonova-Catcher optical upper limit
  30. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  31. GRB 260104A: Swift-BAT refined analysis
  32. GRB 260101A: Swift-BAT refined analysis
  33. Swift GRB 251230A: Global MASTER-Net OT detection
  34. Fermi GRB 260107A: Global MASTER-Net observations report
  35. GRB 260102A: AbAO optical observations
  36. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  37. Fermi GRB 260105A: Global MASTER-Net observations report
  38. EP260105a: FTW optical observations
  39. EP260104a: FTW optical observations
  40. GRB 260105A: SVOM/GRM observation
  41. GRB 260105B: SVOM/GRM observation
  42. FRB 20251229A: COLIBRÍ optical upper limits
  43. Fermi GRB 260105B: Global MASTER-Net observations report
  44. EP260105a: SVOM/VT optical upperlimit
  45. EP260105a: refined analysis of the EP-WXT and EP-FXT observations
  46. EP260105a: LCO Optical Upper limit
  47. EP260104a: Global MASTER-Net observations report
  48. GRB 260101A: COLIBRÍ optical upper limits
  49. EP260105a: Global MASTER-Net observations report
  50. GRB 260103A: Insight-HXMT/HE detection
  51. GRB 260104A: COLIBRÍ optical upper limits
  52. Fermi GRB 260104B: Global MASTER-Net observations report
  53. Swift GRB 260104A: Global MASTER-Net observations report
  54. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  55. GRB 260101A: Swift/UVOT Detection
  56. GRB 260103A: GECAM-B observation of a burst
  57. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  58. GRB 260101A: COLIBRÍ optical observations
  59. Fermi GBM Sub-Threshold Detection of GRB 260102A
  60. GRB 260102A: EP-FXT follow-up observation
  61. EP260101a: Global MASTER-Net observations report
  62. GRB 260102A: LCO optical upper limits
  63. GRB 260102A: Swift-XRT observations
  64. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  65. GRB 251230A / EP251230a: GECAM-B detection
  66. GRB 260102A: SVOM/VT optical counterpart
  67. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  68. GRB 260102A: Swift ToO observations
  69. GRB 260101A: Fermi GBM Observation
  70. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  71. GRB 260101A: GECAM-B detection
  72. GRB 260101A: NOT spectroscopic observations
  73. GRB 260101A: SVOM/GRM observation
  74. Swift GRB 260101A: Global MASTER-Net observations report
  75. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  76. GRB 260101A: LCO detection of the optical counterpart
  77. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  78. GRB 251230A: GRANDMA/TAROT Early Detection
  79. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  80. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  81. EP251229a: Optical upper limit with Kinder observations
  82. GRB 251230A: 1.3m DFOT optical upper limit
  83. GRB 251222A: Mondy Optical Observations
  84. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  85. GRB 251230A: Swift/UVOT detection
  86. GRB251230A: 7DT optical upper limits
  87. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  88. EP251229a: BOOTES-2 early optical upper limit
  89. GRB 251230A: GOTO optical upper limit
  90. EP251229a: NOT optical upper limits
  91. GRB 251230A / EP251230a: SVOM/VT optical observation
  92. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  93. GRB 251230A: Early optical counterpart detection by LCO.
  94. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  95. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  96. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  97. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  98. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  99. Swift GRB 251230A: Global MASTER-Net observations report
  100. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart

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