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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. Konus-Wind observation of GRB 051008
  2. GRB051008: Final refined analysis of the Swift-BAT burst
  3. GRB 051008: R-band upper limit
  4. GRB051008: Refined analysis of the Swift-BAT burst
  5. GRB051008: Radio Observation
  6. GRB 051008: Swift XRT position
  7. GRB 051008, optical observations
  8. GRB 051008: early Swift XRT analysis
  9. GRB 051008: Swift UVOT Candidate
  10. GRB051008: Swift-BAT detection of a bright burst
  11. GRB 051006: P60 Observations
  12. grb test
  13. GRB 051006: XRT refined analysis
  14. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  15. GRB 051006: optical observations at Sierra Nevada
  16. GRB051006: Refined analysis of the Swift-BAT burst
  17. GRB 051006: XRT position
  18. GRB051006: Swift detection of a burst
  19. GRB 050906, summary of radio observations
  20. Swift-BAT triggers 158261 and 158262 Retraction
  21. GRB051001: Swift UVOT Upper Limits
  22. GRB 050925: Second Epoch WSRT Radio Observations
  23. GRB 051001: Swift XRT refined analysis
  24. GRB 051001, optical observations at Mt. John
  25. GRB 051001: I-band limit
  26. GRB 051001: AAT infra-red observations
  27. GRB 051001: Swift-BAT refined analysis
  28. GRB 051001: Swift Detection of a Burst
  29. GRB 051001: ROTSE-III Optical Limits
  30. GRB050908: optical observations
  31. GRB050922C: optical observation
  32. GRB050922B: optical limit
  33. GRB 050922C: further VLT observations
  34. GRB 050820A: NIR photometry at the TNG
  35. GRB050922C: UVES/VLT high resolution spectroscopy
  36. GRB050925: Swift/XRT limits
  37. GRB/SGR 050925: IR Observations
  38. GRB050922C - Swift UVOT preliminary analysis
  39. GRB 050922C: break in the lightcurve
  40. GRB 050925: WSRT Radio Observations
  41. GRB050925: Swift UVOT upper limits
  42. Refined analysis of the Swift-BAT soft short burst
  43. GRB 050925 : I-band observation at Xinglong observatory
  44. GRB050925: Faulkes Telescope North R-band limit
  45. GRB050925: Swift-BAT detection of a short burst
  46. GRB 050922B: Correction to BAT refined analysis, longer burst
  47. GRB050922C: TNG spectroscopic observations
  48. GRB050922B: refined XRT analysis
  49. Konus-Wind observation of GRB 050922C
  50. GRB 050922C: Refined redshift
  51. GRB050922B: Swift UVOT early upper limits.
  52. GRB OT observation
  53. GRB050922C: observation at MonteBoo
  54. INT 2.5m limit for GRB050922B
  55. GRB 050922B: optical limit
  56. GRB050922C: Optical Observations
  57. GRB 050922C: Swift XRT refined analysis
  58. HETE Fregate observations of GRB 050922C
  59. GRB 050922C: Swift-BAT refined analysis
  60. GRB 050922B: Swift-BAT refined analysis
  61. GRB050922C: optical observations
  62. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  63. GRB 050922C: optical obserations
  64. GRB 050922C: NOT optical observations
  65. GRB 050922A: Analysis of Swift/XRT TOO observation
  66. GRB 050922C: Swift detection of a bright burst
  67. GRB 050922C: ROTSE-IIId Refined Analysis
  68. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  69. GRB 050922B: ROTSE-III Optical Limits
  70. GRB 050922B,optical observation
  71. GRB050922B: Swift-BAT detection of a weak long burst
  72. Possible GRB 050922 detected by INTEGRAL
  73. GRB050918: Possible Swift/XRT detected afterglow
  74. GRB050820B: analysis of the XMM-Newton observation
  75. GRB050916: Swift/UVOT Upper Limits
  76. GRB 050916: Swift-BAT refined analysis
  77. GRB 050918 - A long GRB detected by INTEGRAL
  78. GRB 050915a: Radio Observations
  79. Swift-BAT trigger 155764 is not a GRB
  80. Swift-BAT trigger 155764 is probably not a GRB
  81. Swift trigger 155764: bad XRT centroid
  82. Swift-BAT trigger 155535 is definitely not a GRB
  83. GRB050916 : Swift-XRT refined analysis
  84. GRB 050916: XRT position
  85. GRB 050915b, SMARTS optical/IR observations of the XRT position
  86. GRB 050915B: Swift-BAT refined analysis
  87. GRB 050915B: Swift/UVOT Upper Limits
  88. GRB050916: Swift-BAT detection of a long weak burst
  89. GRB 050915a: IR Transient
  90. GRB 050915B: XRT position
  91. GRB 050915b, SMARTS optical/IR observations
  92. GRB050915B: Swift-BAT detection of a long bright burst
  93. GRB050915: Swift/UVOT upper limits
  94. GRB 050915: KAIT optical limit
  95. GRB 050915: IR Observations
  96. GRB 050915: Swift XRT refined analysis
  97. GRB 050915: Swift-BAT refined analysis
  98. GRB050915: P60 Optical Observations
  99. GRB050915, optical observations
  100. GRB050915: XRT position

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