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

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