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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"

37707 results found.

  1. GRB 260105A: SVOM/GRM observation
  2. GRB 260105B: SVOM/GRM observation
  3. Fermi GRB 260105B: Global MASTER-Net observations report
  4. GRB 260105B: Fermi GBM Final Real-time Localization
  5. GRB 260105A: Fermi GBM Final Real-time Localization
  6. GRB 260101A: COLIBRÍ optical upper limits
  7. GRB 260103A: Insight-HXMT/HE detection
  8. GRB 260104A: COLIBRÍ optical upper limits
  9. GRB 260104C: Fermi GBM Final Real-time Localization
  10. Fermi GRB 260104B: Global MASTER-Net observations report
  11. Swift GRB 260104A: Global MASTER-Net observations report
  12. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  13. GRB 260104A: Swift-XRT refined Analysis
  14. GRB 260104A: Enhanced Swift-XRT position
  15. GRB 260101A: Swift/UVOT Detection
  16. GRB 260103A: GECAM-B observation of a burst
  17. GRB 260104B: Fermi GBM Final Localization
  18. GRB 260104A: Swift detection of a burst
  19. GRB 260103A: SVOM/GRM observation of a possible GRB
  20. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  21. GRB 260101A: COLIBRÍ optical observations
  22. GRB 260102B: Fermi GBM Final Real-time Localization
  23. Fermi GBM Sub-Threshold Detection of GRB 260102A
  24. GRB 260102A: EP-FXT follow-up observation
  25. GRB 260102A: LCO optical upper limits
  26. GRB 260102A: Swift-XRT observations
  27. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  28. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  29. GRB 251230A / EP251230a: GECAM-B detection
  30. GRB 260102A: SVOM/VT optical counterpart
  31. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  32. GRB 260102A: Swift ToO observations
  33. GRB 260101A: Fermi GBM Observation
  34. GRB 260102A: SVOM detection of a burst
  35. GRB 260101A: GECAM-B detection
  36. GRB 260101A: NOT spectroscopic observations
  37. GRB 260101A: SVOM/GRM observation
  38. GRB 260101A: Swift-XRT refined Analysis
  39. Swift GRB 260101A: Global MASTER-Net observations report
  40. GRB 260101A: Enhanced Swift-XRT position
  41. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  42. GRB 260101A: LCO detection of the optical counterpart
  43. GRB 260101A: Swift detection of a burst with an optical counterpart
  44. GRB 260101A: Fermi GBM Final Real-time Localization
  45. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  46. GRB 251230A: GRANDMA/TAROT Early Detection
  47. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  48. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  49. GRB 251230A: 1.3m DFOT optical upper limit
  50. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  51. GRB 251230A: Swift-XRT refined Analysis
  52. GRB 251231A: Fermi GBM Final Real-time Localization
  53. GRB 251222A: Mondy Optical Observations
  54. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  55. GRB 251230A: Swift/UVOT detection
  56. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  57. GRB 251230A: GOTO optical upper limit
  58. GRB 251230A / EP251230a: SVOM/VT optical observation
  59. GRB 251230A: Enhanced Swift-XRT position
  60. GRB 251230A: Early optical counterpart detection by LCO.
  61. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  62. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  63. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  64. Swift GRB 251230A: Global MASTER-Net observations report
  65. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  66. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  67. GRB 251226A: Glowbug gamma-ray detection
  68. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  69. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  70. Fermi GRB 251228A: Global MASTER-Net observations report
  71. GRB 251228A: Fermi GBM Final Real-time Localization
  72. GRB 251226A: SVOM/GRM observation
  73. GRB 251226A: GECAM-B detection
  74. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  75. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  76. GRB 251222A: NUTTelA-TAO Early Measurements
  77. GRB 251222A/EP251222b: Optical detection with Kinder observations
  78. GRB 251221A: Swift-BAT refined analysis
  79. GRB 251222A/EP251222b: FTW optical and NIR observations
  80. GRB 251205A: Kilonova-Catcher optical afterglow detection
  81. GRB 251222A: AbAO optical observations
  82. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  83. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  84. GRB 251222A: ZTSH BVRI optical observations
  85. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  86. GRB 251222A: Continued 1.3m DFOT optical observation
  87. GRB 251222A: Fermi GBM Observation
  88. EP251220a: CrAO ZTSh optical observations
  89. GRB 251222A / EP251222b: GECAM-B observation
  90. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  91. Konus-Wind detection of GRB 251222A / EP251222b
  92. GRB 251222A: Swift-XRT afterglow detection
  93. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  94. GRB 251222A / EP251222b: GOTO optical counterpart detection
  95. GRB 251222A / EP251222b: LCO optical observations
  96. GRB 251222A: 1.3m DFOT optical detection
  97. GRB251221A: 7DT optical upper limits
  98. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  99. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  100. EP251222b/GRB 251222A: SVOM/GRM observation

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