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

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