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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

19602 results found.

  1. GRB 221226A: Fermi GBM detection
  2. IPN triangulation of GRB 221226A
  3. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  4. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  5. GRB 221226B Swift-BAT refined analysis
  6. GRB 221226B: Swift-UVOT Detection
  7. GRB 221226B: Fermi GBM Observation
  8. GRB 221226B: Swift-XRT refined Analysis
  9. GRB 221226B: VLT/X-shooter redshift and host galaxy
  10. GRB 221226B: Enhanced Swift-XRT position
  11. GRB 221226B: Swift detection of a burst
  12. Swift GRB221226.95: Global MASTER-Net observations report
  13. GRB 221215A: Fermi GBM Detection
  14. GRB 221216A: Swift/UVOT Upper Limits
  15. GRB 221216A: Fermi GBM observation
  16. GRB 221216A: Swift-XRT refined Analysis
  17. GRB 221216A: AKO Upper Limit
  18. GRB 221215A: Swift-XRT observations
  19. GRB 221216A: Enhanced Swift-XRT position
  20. Swift GRB 221216A: Global MASTER-Net observations report
  21. GRB 221216A: Zadko observatory - Gingin optical observations
  22. GRB 221216A: Nanshan/NEXT optical upper limits
  23. GRB 221216A: Swift detection of a burst
  24. GRB 221215A: Swift ToO observations
  25. GRB 221215A: Swift/BAT-GUANO arcminute localization
  26. Swift GRB221215.15: Global MASTER-Net observations report
  27. Swift Trigger 1144538 is not a GRB
  28. GRB 221009A: MuSCAT3 observations
  29. GRB 221206B: Fermi GBM observation
  30. GRB 221206B: Swift-XRT observations
  31. GRB 221206B: Detection by GRBAlpha
  32. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  33. GRB 221206B: Swift ToO observations
  34. Swift/BAT trigger #1143281 is not a GRB
  35. Swift GRB221204.45 AKO Upper Limit
  36. Swift GRB221204.45: Global MASTER-Net observations report
  37. GRB 221202A: Swift/UVOT Detection
  38. GRB 221202A: Swift-BAT refined analysis
  39. GRB 221202A: VLT/FORS2 Afterglow Discovery
  40. GRB 221201A: Swift-BAT refined analysis
  41. GRB 221201A: Fermi GBM observation
  42. GRB 221202A: Swift-XRT refined Analysis
  43. GRB 221202A: Enhanced Swift-XRT position
  44. GRB 221202A: MeerLICHT upper limits
  45. GRB 221202A: Swift detection of a burst
  46. Swift GRB221202.84: Global MASTER-Net observations report
  47. GCN: GRB 221201A: Swift/UVOT Upper Limits
  48. GRB 221201A: Swift-XRT refined Analysis
  49. GRB 221201A: Enhanced Swift-XRT position
  50. Swift GRB 221201A: Global MASTER-Net observations report
  51. Konus-Wind detection of GRB 221124A
  52. GRB 221201A: Swift detection of a burst
  53. GRB 221126A: Fermi GBM observation
  54. GRB 221126A: AGILE detection
  55. GRB 221126A: AstroSat CZTI detection
  56. GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV
  57. IPN triangulation of GRB 221124A (long)
  58. GRB 221124A: Swift/BAT-GUANO detection
  59. GRB 221120A: Detection by VZLUSAT-2
  60. GRB 221009A:DAMPE observed a 34.7 GeV photon at 1.36 hour after the GBM trigger
  61. IPN triangulation of GRB 221121A (long)
  62. GRB 221120A: Swift-BAT refined analysis
  63. GRB 221120A: AKO Telescope Upper Limits
  64. GRB221120A: WIRC near-IR imaging of the afterglow candidate
  65. GRB 221120A: Liverpool Telescope Upper Limits
  66. GRB 221120A: Fermi GBM observation
  67. GRB 221120A: Swift-XRT refined Analysis
  68. GRB 221120A: Enhanced Swift-XRT position
  69. GRB221120A: Montarrenti Observatory Upper Limit
  70. GRB 221120A is a short burst
  71. GRB 221120A: Swift/UVOT Upper Limits
  72. GRB 221120A: GIT upper limits on optical afterglow
  73. GRB 221120A: Swift detection of a likely short burst
  74. GRB 221119A: Fermi-LAT detection
  75. GRB 221009A: Japanese VLBI Network observation
  76. GRB 221115B: CALET Gamma-Ray Burst Monitor detection
  77. Correction to GCN 32646 (GRB 221009A (Swift J1913.1+1946): MeerLICHT observations)
  78. GRB 221115B : MeerLICHT upper limits
  79. GRB 221115A: Fermi GBM detection
  80. GRB 221115B: Swift/BAT-GUANO arcminute localization
  81. GRB 221115A: Swift/BAT-GUANO detection
  82. GRB 221110A: GRANDMA observations
  83. GRB 221009A: GRANDMA/Kilonova-Catcher observations
  84. GRB 221110A: Swift/UVOT Detection and Corrected UVOT Position
  85. GRB 221110A: Swift-BAT refined analysis
  86. GRB 221110A: Swift-XRT refined Analysis
  87. GRB 221110A: Enhanced Swift-XRT position
  88. GRB 221110A: LCOGT Optical Afterglow Detection
  89. GRB 221110A: Swift detection of a burst with an optical counterpart
  90. Swift GRB221110.10: Global MASTER-Net OT detection
  91. Swift GRB221110.10: Global MASTER-Net observations report
  92. GRB 221107A: Fermi GBM Observation
  93. GRB 221107A: Detection by GRBAlpha
  94. GRB 221107A: Swift/BAT-GUANO detection outside the coded FOV
  95. Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)
  96. GRB 221029A: CALET Gamma-Ray Burst Monitor detection
  97. High-precision position of the compact radio counterpart to GRB221009A
  98. GRB 221028A: GRANDMA observations
  99. GRB 221027B: GRANDMA observations
  100. GRB 221028A: Detection by VZLUSAT-2

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