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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 081102: RTT150 Optical observations
  2. GRB 081110: Fermi GBM detection
  3. GRB 081110: MASTER: first optical observations Fermi GRB
  4. GRB 081109: TAROT La Silla observatory optical observations
  5. GRB 081102: MASTER refind and final results
  6. GRB 081109: GROND redshift limit and host extinction
  7. GRB 081025: Swift-XRT further analysis
  8. GRB 081024B: Swift-XRT late-time observations
  9. Swift-BAT refined analysis of trigger 334129
  10. GRB 081109B: Swift/UVOT refined analysis
  11. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  12. GRB 081109A: Possible Swift-UVOT detection
  13. GRB 081109A: Faulkes Telescope South observations
  14. GRB 081109A, Swift-BAT refined analysis
  15. GRB 081109A: Swift-XRT refined analysis
  16. GRB 081109: Fermi GBM detection
  17. GRB 081109: Swift/UVOT upper limits
  18. GRB 081109A optical upper limit
  19. Swift-BAT Trigger 334129: possible burst
  20. GRB 081109: REM NIR afterglow detection
  21. GRB 081109: Swift detection of a burst
  22. GRB 081028 - PAIRITEL NIR detection
  23. GRB 081024C: Fermi Gamma-ray Burst Monitor detection
  24. SGR 1806-20: Fermi GBM detection
  25. GRB 081102B: Fermi GBM detection
  26. GRB 081105B: Fermi GBM detection
  27. GRB 081107: Fermi GBM detection
  28. GRB 081104: GROND found no Optical/NIR Afterglow
  29. GRB 081105: GROND Upper Limits
  30. Radio observation of GRB 080523 with ATCA
  31. Radio observation of GRB 080520 with ATCA
  32. GRB 081105: Observations from OSN
  33. UVOT/Swift observations of GRB081105
  34. Swift-XRT observations of GRB 081105
  35. GRB 081101B: Fermi GBM detection
  36. Radio observation of GRB 080516 with ATCA
  37. GRB 081105 Swift/BAT and IPN Localization
  38. GRB 081025: Fermi GBM observation
  39. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  40. GRB 081104: refined XRT analysis
  41. GRB 081104: Enhanced Swift-XRT position
  42. GRB 081104: Swift-BAT refined analysis
  43. GRB081104: Swift/UVOT Upper Limits
  44. Fermi-GBM detection of a Solar Flare
  45. Fermi Detection of GRB 081102
  46. GRB 081104 : Faulkes Telescope South observations
  47. GRB 081104: Swift-XRT position
  48. GRB 081104: Swift detection of a burst
  49. Radio observation of GRB 080130 with ATCA
  50. GRB 081102: MASTER prompt optical limit
  51. GRB 081102: Swift-XRT refined analysis
  52. GRB 081102: Swift/UVOT refined analysis
  53. GRB 081102: Swift-BAT refined analysis
  54. GRB 081102: Enhanced Swift-XRT position
  55. Radio observation of GRB 080218b with ATCA
  56. Radio observation of GRB 080229a with ATCA
  57. GRB 081102: MASTER VWF promt observation
  58. GRB 081102: OPTIMA-Burst optical upper limit
  59. GRB 081102: Swift detection of a burst
  60. SGR 0501+4516: optical observations in August
  61. GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
  62. SGR 0623-0006 or GRB 081101: Swift-XRT refined analysis
  63. SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
  64. Swift-BAT triggered on a probable GRB 081101 (trigger=333320)
  65. GRB 081024B: BTA deep optical observations
  66. GRB 081028: CrAO optical observations
  67. GRB 081024B: new Swift-XRT observations
  68. Radio observation of GRB 080229b with ATCA
  69. GRB 081029, SMARTS optical/IR afterglow observations
  70. GRB 081024B: VLA radio observation
  71. GRB 081029: UVOT Detection of the Optical Afterglow
  72. GRB 081029: PROMPT Detections
  73. GRB 081029: Redshift Confirmation from Gemini-South
  74. GRB 081029: Swift-BAT refined analysis
  75. GRB081029: Swift XRT refined analysis
  76. GRB 081025: Suzaku WAM observation of the prompt emission
  77. GRB 081024B: Suzaku WAM observation of the prompt emission
  78. GRB 081029: Enhanced Swift-XRT position
  79. GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
  80. GRB 081029: REM observations
  81. Radio observation of GRB 080303 with ATCA
  82. Radio observation of GRB 080411 with ATCA
  83. GRB 081029: UVES/VLT Absorption Redshift
  84. GRB 081029: GROND Detection of the Optical/NIR Afterglow
  85. GRB 081029: ROTSE-III Detection of Optical Counterpart
  86. GRB 081029: Swift detection of a burst
  87. GRB 081028: Magellan redshift
  88. GRB 081028B: Fermi GBM detection
  89. GRB 081021: Fermi GBM detection
  90. GRB081028: UVOT detection of a brightening afterglow
  91. Swift UVOT observations of GRB081028
  92. GRB 081028: Swift-XRT refined analysis
  93. GRB 081028, Swift-BAT refined analysis
  94. GRB 081028: Enhanced Swift-XRT position
  95. GRB 081028: TAROT Calern observatory optical observations
  96. GRB 081028: optical observations at the NOT
  97. GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
  98. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  99. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  100. GRB 081028: Swift detection of a burst

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