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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"

27774 results found.

  1. GRB 221202A: Swift/UVOT Detection
  2. GRB 221202A: Swift-BAT refined analysis
  3. GRB 221202A: VLT/FORS2 Afterglow Discovery
  4. GRB 221201A: Swift-BAT refined analysis
  5. GRB 221203A: Fermi GBM Final Real-time Localization
  6. GRB 221201A: Fermi GBM observation
  7. GRB 221202A: Swift-XRT refined Analysis
  8. GRB 221202A: Enhanced Swift-XRT position
  9. GRB 221202A: MeerLICHT upper limits
  10. GRB 221202B: Fermi GBM Final Real-time Localization
  11. GRB 221202A: Swift detection of a burst
  12. Swift GRB221202.84: Global MASTER-Net observations report
  13. GCN: GRB 221201A: Swift/UVOT Upper Limits
  14. GRB 221201A: Swift-XRT refined Analysis
  15. GRB 221201A: Enhanced Swift-XRT position
  16. Swift GRB 221201A: Global MASTER-Net observations report
  17. Konus-Wind detection of GRB 221124A
  18. GRB 221201A: Swift detection of a burst
  19. GRB 221201A: Fermi GBM Final Real-time Localization
  20. GRB 221126A: Fermi GBM observation
  21. GRB 221126A: AGILE detection
  22. GRB 221127A: Detection by GRBAlpha
  23. GRB 221126A: AstroSat CZTI detection
  24. GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV
  25. IPN triangulation of GRB 221124A (long)
  26. GRB 221126A: Fermi GBM Final Real-time Localization
  27. GRB 221124A: Swift/BAT-GUANO detection
  28. GRB 221120A: Detection by VZLUSAT-2
  29. GRB 221124A: CALET Gamma-Ray Burst Monitor detection
  30. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  31. GRB 221122A: Detection by GRBAlpha
  32. GRB 221121A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 221009A:DAMPE observed a 34.7 GeV photon at 1.36 hour after the GBM trigger
  34. IPN triangulation of GRB 221121A (long)
  35. GRB 221120A: Swift-BAT refined analysis
  36. GRB221121A: AstroSat CZTI detection
  37. GRB 221120A: AKO Telescope Upper Limits
  38. GRB221120A: WIRC near-IR imaging of the afterglow candidate
  39. GRB 221120A: Liverpool Telescope Upper Limits
  40. GRB 221120A: Fermi GBM observation
  41. GRB 221120A: Swift-XRT refined Analysis
  42. GRB 221120A: Enhanced Swift-XRT position
  43. GRB221120A: Montarrenti Observatory Upper Limit
  44. GRB 221121A: Fermi GBM Final Real-time Localization
  45. GRB 221120A is a short burst
  46. GRB 221120A: Swift/UVOT Upper Limits
  47. GRB 221120A: GIT upper limits on optical afterglow
  48. GRB 221120A: Swift detection of a likely short burst
  49. GRB 221119A: Fermi GBM detection
  50. GRB 221119A: Detection by GRBAlpha
  51. GRB 221119A: Fermi-LAT detection
  52. GRB 221119A: Fermi GBM Final Real-time Localization
  53. GRB 221009A: Japanese VLBI Network observation
  54. GRB 221115B: CALET Gamma-Ray Burst Monitor detection
  55. GRB 221114A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 221118A: Fermi GBM Final Real-time Localization
  57. Correction to GCN 32646 (GRB 221009A (Swift J1913.1+1946): MeerLICHT observations)
  58. GRB 221115B : MeerLICHT upper limits
  59. GRB 221115A: Fermi GBM detection
  60. GRB 221115B: Swift/BAT-GUANO arcminute localization
  61. GRB 221115A: Swift/BAT-GUANO detection
  62. GRB 221110A: GRANDMA observations
  63. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 November 9
  64. GRB 221112A: Detection by GRBAlpha
  65. GRB 221112A: Fermi GBM Final Real-time Localization
  66. GRB 221009A: GRANDMA/Kilonova-Catcher observations
  67. GRB 221110A: Swift/UVOT Detection and Corrected UVOT Position
  68. GRB 221110A: Swift-BAT refined analysis
  69. GRB 221110A: Swift-XRT refined Analysis
  70. GRB 221110A: Enhanced Swift-XRT position
  71. GRB 221110A: VLT/X-shooter redshift
  72. GRB 221110A: COATLI Afterglow detection
  73. GRB 221110A: LCOGT Optical Afterglow Detection
  74. GRB 221110A: Swift detection of a burst with an optical counterpart
  75. Swift GRB221110.10: Global MASTER-Net OT detection
  76. Swift GRB221110.10: Global MASTER-Net observations report
  77. GRB 221104A: Fermi GBM Final Localization
  78. GRB 221108A: Fermi GBM Final Localization
  79. GRB 221107A: Fermi GBM Observation
  80. GRB 221107A: Detection by GRBAlpha
  81. GRB 221107A: Swift/BAT-GUANO detection outside the coded FOV
  82. GRB 221107A: Fermi GBM Final Localization
  83. Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)
  84. IceCube-221104A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 221029A: CALET Gamma-Ray Burst Monitor detection
  86. High-precision position of the compact radio counterpart to GRB221009A
  87. GRB 221028A: GRANDMA observations
  88. GRB 221027B: GRANDMA observations
  89. GRB 221028A: Detection by VZLUSAT-2
  90. GRB 221027C: AstroSat CZTI detection
  91. Konus-Wind detection of GRB 221022C
  92. GRB 221029A: Fermi GBM Final Localization
  93. GRB 221028A: Swift-XRT refined Analysis
  94. GRB 221028A: 1.3m DFOT Optical upper limit
  95. GRB 221028A, Swift-BAT refined analysis
  96. GRB 221027B: Swift-BAT refined analysis
  97. GRB 221029A: Swift/BAT-GUANO detection outside the coded FOV
  98. GRB 221029A: Detection by GRBAlpha
  99. Trigger 1132968: Swift trigger is the Crab
  100. GRB 221028A: HCT optical upper limit

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