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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"

20357 results found.

  1. GRB 081126: Enhanced Swift-XRT position
  2. GRB 081126: TAROT Calern observatory optical observations
  3. GRB 081126: Swift detection of a burst
  4. GRB 081121, SMARTS optical/IR afterglow observations
  5. GRB081121: Fermi GBM detection
  6. GRB081121: Refined Swift/UVOT observations
  7. GRB 081121: Swift-XRT refined analysis
  8. GRB 081121: Enhanced Swift-XRT position
  9. GRB 081121: GROND observations
  10. GRB081121: Swift/UVOT observations
  11. GRB 081121: ROTSE-III Detection of Optical Counterpart
  12. GRB081118 : optical upper limit
  13. VLA Radio upper limit on GRB 081118
  14. GRB 081118: Swift-XRT refined analysis
  15. GRB 081118: GROND detection of afterglow
  16. GRB 081118: optical afterglow candidate
  17. GRB 081118: Swift UVOT Upper Limits
  18. GRB 081118: Enhanced Swift-XRT position
  19. GRB 081118: Swift detection of a burst
  20. GRB 081109A: confirmation of possible detection host galaxy
  21. Further Swift-XRT observations of the probable GRB 081105.
  22. GRB 081102: RTT150 Optical observations
  23. GRB 081110: MASTER: first optical observations Fermi GRB
  24. GRB 081109: TAROT La Silla observatory optical observations
  25. GRB 081102: MASTER refind and final results
  26. GRB 081109: GROND redshift limit and host extinction
  27. GRB 081025: Swift-XRT further analysis
  28. GRB 081024B: Swift-XRT late-time observations
  29. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  30. GRB 081109A: Swift-XRT refined analysis
  31. Swift-BAT Trigger 334129: possible burst
  32. GRB 081109: REM NIR afterglow detection
  33. GRB 081109: Swift detection of a burst
  34. GRB 081104: GROND found no Optical/NIR Afterglow
  35. GRB 081105: GROND Upper Limits
  36. Radio observation of GRB 080523 with ATCA
  37. Radio observation of GRB 080520 with ATCA
  38. GRB 081105: Observations from OSN
  39. Swift-XRT observations of GRB 081105
  40. Radio observation of GRB 080516 with ATCA
  41. GRB 081105 Swift/BAT and IPN Localization
  42. GRB 081104: GROND Detection of the Optical/NIR Afterglow Candidate?
  43. GRB 081104: refined XRT analysis
  44. GRB 081104: Enhanced Swift-XRT position
  45. Fermi-GBM detection of a Solar Flare
  46. GRB 081104 : Faulkes Telescope South observations
  47. Radio observation of GRB 080130 with ATCA
  48. GRB 081102: MASTER prompt optical limit
  49. GRB 081102: Swift-XRT refined analysis
  50. GRB 081102: Enhanced Swift-XRT position
  51. Radio observation of GRB 080218b with ATCA
  52. Radio observation of GRB 080229a with ATCA
  53. GRB 081102: MASTER VWF promt observation
  54. GRB 081102: Swift detection of a burst
  55. SGR 0501+4516: optical observations in August
  56. SGR 0623-0006 or GRB 081101: Swift-BAT/-XRT refined analysis
  57. GRB 081024B: BTA deep optical observations
  58. GRB 081024B: new Swift-XRT observations
  59. Radio observation of GRB 080229b with ATCA
  60. GRB 081024B: VLA radio observation
  61. GRB 081029: UVOT Detection of the Optical Afterglow
  62. GRB 081029: Enhanced Swift-XRT position
  63. GRB 081028: GROND Confirmation of the Optical/NIR Afterglow
  64. GRB 081029: REM observations
  65. Radio observation of GRB 080303 with ATCA
  66. Radio observation of GRB 080411 with ATCA
  67. GRB 081029: GROND Detection of the Optical/NIR Afterglow
  68. GRB 081028B: Fermi GBM detection
  69. Swift UVOT observations of GRB081028
  70. GRB 081028: Enhanced Swift-XRT position
  71. GRB 081028: TAROT Calern observatory optical observations
  72. GRB 081028: optical observations at the NOT
  73. GRB 081028: GROND Detection of the Optical/NIR Afterglow Candidate
  74. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
  75. Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
  76. GRB 081028: Swift detection of a burst
  77. GRB 081024: No radio detection with the VLA
  78. GRB081025: RTT150 optical observations
  79. GRB081024B: P200 Observations
  80. GRB 081024B: Swift-XRT further observations
  81. Swift UVOT observations of GRB081024B
  82. GRB 081025: Swift-XRT position
  83. GRB 081024B: Swift-XRT observations
  84. GRB 081025: Burst detection from Swift-BAT slew data
  85. GRB 081024: Enhanced Swift-XRT position
  86. GRB 081024: Faulkes Telescope North optical observations
  87. GRB 081024A: ROTSE-III Optical Limits
  88. GRB 081024: Swift detection of a burst
  89. GRB 081016A: Swift-XRT refined analysis
  90. Swift detection of a possible burst (trigger 332287)
  91. GRB 081017: REM early observations
  92. GRB 081011: Swift XRT refined analysis
  93. GRB 081016B: Enhanced Swift-XRT position
  94. GRB 081016B: ROTSE-III Optical Limits
  95. GRB 081016B: Swift detection of a burst
  96. GRB 081011: Enhanced Swift-XRT position
  97. Swift detection of flare on CC Eri
  98. Trigger 331721 Due to Swift startracker loss-of-lock
  99. Detection of flare star Algol in Swift-BAT slew data
  100. GRB 081012: GROND upper limits

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