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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"

28286 results found.

  1. GRB 260101A: Swift/UVOT Detection
  2. GRB 260103A: GECAM-B observation of a burst
  3. GRB 260104A: Swift detection of a burst
  4. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  5. GRB 260101A: COLIBRÍ optical observations
  6. SVOM GRB260103.08: Global MASTER-Net observations report
  7. SVOM GRB260102A: Global MASTER-Net observations report
  8. Fermi GBM Sub-Threshold Detection of GRB 260102A
  9. GRB 260102A: EP-FXT follow-up observation
  10. EP260101a: Global MASTER-Net observations report
  11. GRB 260102A: LCO optical upper limits
  12. GRB 260102A: Swift-XRT observations
  13. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 260101A: Fermi GBM Observation
  15. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  16. GRB 260102A: SVOM detection of a burst
  17. GRB 260101A: NOT spectroscopic observations
  18. GRB 260101A: SVOM/GRM observation
  19. GRB 260101A: Swift-XRT refined Analysis
  20. Swift GRB 260101A: Global MASTER-Net observations report
  21. GRB 260101A: Enhanced Swift-XRT position
  22. EP260101a: Einstein Probe detection of an X-ray transient
  23. GRB 260101A: LCO detection of the optical counterpart
  24. GRB 260101A: Swift detection of a burst with an optical counterpart
  25. GRB 260101A: Fermi GBM Final Real-time Localization
  26. SVOM GRB251231.57: Global MASTER-Net observations report
  27. GRB 251230A: GRANDMA/TAROT Early Detection
  28. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  29. EP251229a: Optical upper limit with Kinder observations
  30. GRB 251230A: 1.3m DFOT optical upper limit
  31. GRB 251230A: Swift-XRT refined Analysis
  32. GRB 251222A: Mondy Optical Observations
  33. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  34. GRB 251230A: Swift/UVOT detection
  35. GRB251230A: 7DT optical upper limits
  36. GRB 251230A: GOTO optical upper limit
  37. EP251229a: NOT optical upper limits
  38. GRB 251230A / EP251230a: SVOM/VT optical observation
  39. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  40. GRB 251230A: Enhanced Swift-XRT position
  41. GRB 251230A: Early optical counterpart detection by LCO.
  42. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  43. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  44. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  45. Swift GRB 251230A: Global MASTER-Net observations report
  46. EP251229a: Global MASTER-Net observations report
  47. EP251229a: Einstein Probe detection of an X-ray transient
  48. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  49. GRB 251226A: Glowbug gamma-ray detection
  50. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  51. Fermi GRB 251228A: Global MASTER-Net observations report
  52. GRB 251226A: SVOM/GRM observation
  53. GRB 251226A: GECAM-B detection
  54. SVOM GRB251227.07: Global MASTER-Net observations report
  55. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  56. IceCube Alert 251225.84: Global MASTER-Net observations report
  57. GRB 251222A/EP251222b: Optical detection with Kinder observations
  58. EP251222a: Optical upper limit with Kinder observations
  59. GRB 251221A: Swift-BAT refined analysis
  60. GRB 251205A: Kilonova-Catcher optical afterglow detection
  61. GRB 251222A: AbAO optical observations
  62. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  63. GRB 251222A: ZTSH BVRI optical observations
  64. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  65. GRB 251222A: Continued 1.3m DFOT optical observation
  66. EP251220a: 3.6m DOT optical afterglow detection
  67. GRB 251222A: Fermi GBM Observation
  68. EP251220a: CrAO ZTSh optical observations
  69. EP251221a: PRIME upper limit
  70. EP251222a: Global MASTER-Net observations report
  71. EP251221a: Liverpool Telescope upper limits
  72. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  73. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  74. GRB 251222A: Swift-XRT afterglow detection
  75. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  76. EP251222a: NTT/ULTRACAM optical observations
  77. GRB 251222A / EP251222b: GOTO optical counterpart detection
  78. GRB 251222A / EP251222b: LCO optical observations
  79. GRB 251222A: 1.3m DFOT optical detection
  80. GRB251221A: 7DT optical upper limits
  81. EP251222a: GSP Optical Counterpart Detection
  82. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  83. EP251222a: Einstein Probe detection of an X-ray transient
  84. EP251221a: Global MASTER-Net observations report
  85. GRB 251222A: PRIME near-infrared detection
  86. EP251221a: NOT optical upper limit
  87. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  88. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  89. IPN triangulation of GRB 251220B (short)
  90. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  91. GRB 251222A: SVOM/VT optical candidate
  92. GRB 251222A: SVOM detection of a long burst
  93. SVOM GRB251222A: Global MASTER-Net observations report
  94. EP251220a: PRIME upper limit
  95. GRB 251221A: PRIME near-infrared observation
  96. GRB 251221A: UAFO and Mondy optical upper limit
  97. GRB 251221A: Swift-XRT refined Analysis
  98. EP251221a: Einstein Probe detection of a fast X-ray transient
  99. GRB 251221A: Swift/UVOT Upper Limits
  100. GRB 251221A: Enhanced Swift-XRT position

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