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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"
  1. GRB 081109A, Swift-BAT refined analysis
  2. GRB 081109A: Swift-XRT refined analysis
  3. GRB 081109: Fermi GBM detection
  4. GRB 081109: Swift/UVOT upper limits
  5. GRB 081109A optical upper limit
  6. Swift-BAT Trigger 334129: possible burst
  7. GRB 081109: REM NIR afterglow detection
  8. GRB 081109: Swift detection of a burst
  9. GRB 081028 - PAIRITEL NIR detection
  10. GRB 081024C: Fermi Gamma-ray Burst Monitor detection
  11. SGR 1806-20: Fermi GBM detection
  12. GRB 081102B: Fermi GBM detection
  13. GRB 081105B: Fermi GBM detection
  14. GRB 081107: Fermi GBM detection
  15. GRB 081104: GROND found no Optical/NIR Afterglow
  16. GRB 081105: GROND Upper Limits
  17. Radio observation of GRB 080523 with ATCA
  18. Radio observation of GRB 080520 with ATCA
  19. GRB 081105: Observations from OSN
  20. UVOT/Swift observations of GRB081105
  21. Swift-XRT observations of GRB 081105
  22. GRB 081101B: Fermi GBM detection
  23. Radio observation of GRB 080516 with ATCA
  24. GRB 081105 Swift/BAT and IPN Localization
  25. GRB 081025: Fermi GBM observation
  26. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  27. GRB 081104: refined XRT analysis
  28. GRB 081104: Enhanced Swift-XRT position
  29. GRB 081104: Swift-BAT refined analysis
  30. GRB081104: Swift/UVOT Upper Limits
  31. Fermi-GBM detection of a Solar Flare
  32. Fermi Detection of GRB 081102
  33. GRB 081104 : Faulkes Telescope South observations
  34. GRB 081104: Swift-XRT position
  35. GRB 081104: Swift detection of a burst
  36. Radio observation of GRB 080130 with ATCA
  37. GRB 081102: MASTER prompt optical limit
  38. GRB 081102: Swift-XRT refined analysis
  39. GRB 081102: Swift/UVOT refined analysis
  40. GRB 081102: Swift-BAT refined analysis
  41. GRB 081102: Enhanced Swift-XRT position
  42. Radio observation of GRB 080218b with ATCA
  43. Radio observation of GRB 080229a with ATCA
  44. GRB 081102: MASTER VWF promt observation
  45. GRB 081102: OPTIMA-Burst optical upper limit
  46. GRB 081102: Swift detection of a burst
  47. SGR 0501+4516: optical observations in August
  48. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  49. SGR 0623-0006 or GRB 081101: Swift-XRT refined analysis
  50. SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
  51. Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
  52. GRB 081024B: BTA deep optical observations
  53. GRB 081028: CrAO optical observations
  54. GRB 081024B: new Swift-XRT observations
  55. Radio observation of GRB 080229b with ATCA
  56. GRB 081029, SMARTS optical/IR afterglow observations
  57. GRB 081024B: VLA radio observation
  58. GRB 081029: UVOT Detection of the Optical Afterglow
  59. GRB 081029: PROMPT Detections
  60. GRB 081029: Redshift Confirmation from Gemini-South
  61. GRB 081029: Swift-BAT refined analysis
  62. GRB081029: Swift XRT refined analysis
  63. GRB 081025: Suzaku WAM observation of the prompt emission
  64. GRB 081024B: Suzaku WAM observation of the prompt emission
  65. GRB 081029: Enhanced Swift-XRT position
  66. GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
  67. GRB 081029: REM observations
  68. Radio observation of GRB 080303 with ATCA
  69. Radio observation of GRB 080411 with ATCA
  70. GRB 081029: UVES/VLT Absorption Redshift
  71. GRB 081029: GROND Detection of the Optical/NIR Afterglow
  72. GRB 081029: ROTSE-III Detection of Optical Counterpart
  73. GRB 081029: Swift detection of a burst
  74. GRB 081028: Magellan redshift
  75. GRB 081028B: Fermi GBM detection
  76. GRB 081021: Fermi GBM detection
  77. GRB081028: UVOT detection of a brightening afterglow
  78. Swift UVOT observations of GRB081028
  79. GRB 081028: Swift-XRT refined analysis
  80. GRB 081028, Swift-BAT refined analysis
  81. GRB 081028: Enhanced Swift-XRT position
  82. GRB 081028: TAROT Calern observatory optical observations
  83. GRB 081028: optical observations at the NOT
  84. GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
  85. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  86. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  87. GRB 081028: Swift detection of a burst
  88. GRB 081025: TLS upper limits
  89. GRB 081024: No radio detection with the VLA
  90. GRB081025: RTT150 optical observations
  91. GRB081024B: P200 Observations
  92. GRB 081024B: Swift-XRT further observations
  93. GRB 081025 BAT refined analysis
  94. Swift UVOT observations of GRB081025
  95. Swift UVOT observations of GRB081024B
  96. Konus-Wind observation of GRB 081025
  97. GRB 081025: Swift-XRT position
  98. GRB 081024B: Swift-XRT observations
  99. GRB 081025: Burst detection from Swift-BAT slew data
  100. GRB 081024B: Fermi Gamma-ray Burst Monitor detection

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