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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"

29105 results found.

  1. GRB 260105A: SVOM/GRM observation
  2. GRB 260105B: SVOM/GRM observation
  3. The EP-WXT trigger 01709251028 is likely a flaring star
  4. Fermi GRB 260105B: Global MASTER-Net observations report
  5. EP260105a: SVOM/VT optical upperlimit
  6. GRB 260105B: Fermi GBM Final Real-time Localization
  7. GRB 260105A: Fermi GBM Final Real-time Localization
  8. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  9. EP260105a: LCO Optical Upper limit
  10. EP260104a: Global MASTER-Net observations report
  11. GRB 260101A: COLIBRÍ optical upper limits
  12. EP260105a: Global MASTER-Net observations report
  13. GRB 260104A: COLIBRÍ optical upper limits
  14. GRB 260104C: Fermi GBM Final Real-time Localization
  15. Fermi GRB 260104B: Global MASTER-Net observations report
  16. Swift GRB 260104A: Global MASTER-Net observations report
  17. GRB 251230A/EP-WXT trigger 01709250693: Mephisto optical upper limits
  18. GRB 260104A: Swift-XRT refined Analysis
  19. GRB 260101A: Swift/UVOT Detection
  20. GRB 260104B: Fermi GBM Final Localization
  21. GRB 260104A: Swift detection of a burst
  22. GRB 260103A: SVOM/GRM observation of a possible GRB
  23. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  24. GRB 260101A: COLIBRÍ optical observations
  25. SVOM GRB260103.08: Global MASTER-Net observations report
  26. GRB 260102B: Fermi GBM Final Real-time Localization
  27. SVOM GRB260102A: Global MASTER-Net observations report
  28. Fermi GBM Sub-Threshold Detection of GRB 260102A
  29. GRB 260102A: EP-FXT follow-up observation
  30. EP260101a: Global MASTER-Net observations report
  31. GRB 260102A: LCO optical upper limits
  32. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  33. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  34. GRB 260102A: SVOM/VT optical counterpart
  35. GRB 260101A: Fermi GBM Observation
  36. GRB 260102A: SVOM detection of a burst
  37. GRB 260101A: GECAM-B detection
  38. GRB 260101A: NOT spectroscopic observations
  39. GRB 260101A: SVOM/GRM observation
  40. GRB 260101A: Swift-XRT refined Analysis
  41. Swift GRB 260101A: Global MASTER-Net observations report
  42. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  43. GRB 260101A: LCO detection of the optical counterpart
  44. GRB 260101A: Swift detection of a burst with an optical counterpart
  45. GRB 260101A: Fermi GBM Final Real-time Localization
  46. SVOM GRB251231.57: Global MASTER-Net observations report
  47. GRB 251230A: GRANDMA/TAROT Early Detection
  48. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  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. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  53. GRB 251230A: Swift-XRT refined Analysis
  54. GRB 251231A: Fermi GBM Final Real-time Localization
  55. GRB 251222A: Mondy Optical Observations
  56. GRB 251230A: Swift/UVOT detection
  57. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  58. GRB 251230A: GOTO optical upper limit
  59. EP251229a: NOT optical upper limits
  60. GRB 251230A / EP251230a: SVOM/VT optical observation
  61. GRB 251230A: Early optical counterpart detection by LCO.
  62. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  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. EP251229a: Global MASTER-Net observations report
  67. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  68. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  69. Fermi GRB 251228A: Global MASTER-Net observations report
  70. The EP-WXT trigger 01709250662 is likely a flaring star
  71. GRB 251228A: Fermi GBM Final Real-time Localization
  72. GRB 251226A: SVOM/GRM observation
  73. GRB 251226A: GECAM-B detection
  74. SVOM GRB251227.07: Global MASTER-Net observations report
  75. The EP-WXT trigger 01709250617 is likely a flaring star
  76. IceCube Alert 251225.84: Global MASTER-Net observations report
  77. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  78. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  79. GRB 251222A: NUTTelA-TAO Early Measurements
  80. GRB 251222A/EP251222b: Optical detection with Kinder observations
  81. EP251222a: Optical upper limit with Kinder observations
  82. GRB 251221A: Swift-BAT refined analysis
  83. GRB 251222A/EP251222b: FTW optical and NIR observations
  84. EP251222a: FTW optical and NIR observations
  85. GRB 251205A: Kilonova-Catcher optical afterglow detection
  86. GRB 251222A: AbAO optical observations
  87. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  88. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  89. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  90. GRB 251222A: ZTSH BVRI optical observations
  91. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  92. GRB 251222A: Continued 1.3m DFOT optical observation
  93. EP251220a: 3.6m DOT optical afterglow detection
  94. GRB 251222A: Fermi GBM Observation
  95. EP251220a: CrAO ZTSh optical observations
  96. EP251221a: PRIME upper limit
  97. EP251222a: Global MASTER-Net observations report
  98. GRB 251222A / EP251222b: GECAM-B observation
  99. EP251221a: Liverpool Telescope upper limits
  100. Konus-Wind detection of GRB 251222A / EP251222b

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