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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 051008: - a high redshift high-luminosity burst?
  2. GRB 051008 - a low redshift low-luminosity burst?
  3. IBAS Alert 2673: not a real GRB
  4. GRB051011: bright nebulae near error box
  5. GRB051011: MASTER optical observation
  6. GRB051008: optical observation
  7. GRB051008: Swift XRT refined analysis
  8. GRB051008 - Swift UVOT upper limits
  9. Konus-Wind observation of GRB 051008
  10. GRB051008: Final refined analysis of the Swift-BAT burst
  11. GRB 051008: R-band upper limit
  12. GRB051008: Refined analysis of the Swift-BAT burst
  13. GRB051008: Radio Observation
  14. GRB 051008: Swift XRT position
  15. GRB 051008, optical observations
  16. GRB 051008: early Swift XRT analysis
  17. GRB 051008: Swift UVOT Candidate
  18. GRB051008: Swift-BAT detection of a bright burst
  19. GRB 051006: P60 Observations
  20. grb test
  21. GRB 051006: XRT refined analysis
  22. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  23. GRB 051006: optical observations at Sierra Nevada
  24. GRB051006: Refined analysis of the Swift-BAT burst
  25. GRB 051006: XRT position
  26. GRB051006: Swift detection of a burst
  27. GRB 050906, summary of radio observations
  28. Swift-BAT triggers 158261 and 158262 Retraction
  29. GRB051001: Swift UVOT Upper Limits
  30. GRB 050925: Second Epoch WSRT Radio Observations
  31. GRB 051001: Swift XRT refined analysis
  32. GRB 051001, optical observations at Mt. John
  33. GRB 051001: I-band limit
  34. GRB 051001: AAT infra-red observations
  35. GRB 051001: Swift-BAT refined analysis
  36. GRB 051001: Swift Detection of a Burst
  37. GRB 051001: ROTSE-III Optical Limits
  38. GRB050908: optical observations
  39. GRB050922C: optical observation
  40. GRB050922B: optical limit
  41. GRB 050922C: further VLT observations
  42. GRB 050820A: NIR photometry at the TNG
  43. GRB050922C: UVES/VLT high resolution spectroscopy
  44. GRB050925: Swift/XRT limits
  45. GRB/SGR 050925: IR Observations
  46. GRB050922C - Swift UVOT preliminary analysis
  47. GRB 050922C: break in the lightcurve
  48. GRB 050925: WSRT Radio Observations
  49. GRB050925: Swift UVOT upper limits
  50. Refined analysis of the Swift-BAT soft short burst
  51. GRB 050925 : I-band observation at Xinglong observatory
  52. GRB050925: Faulkes Telescope North R-band limit
  53. GRB050925: Swift-BAT detection of a short burst
  54. GRB 050922B: Correction to BAT refined analysis, longer burst
  55. GRB050922C: TNG spectroscopic observations
  56. GRB050922B: refined XRT analysis
  57. Konus-Wind observation of GRB 050922C
  58. GRB 050922C: Refined redshift
  59. GRB050922B: Swift UVOT early upper limits.
  60. GRB OT observation
  61. GRB050922C: observation at MonteBoo
  62. INT 2.5m limit for GRB050922B
  63. GRB 050922B: optical limit
  64. GRB050922C: Optical Observations
  65. GRB 050922C: Swift XRT refined analysis
  66. HETE Fregate observations of GRB 050922C
  67. GRB 050922C: Swift-BAT refined analysis
  68. GRB 050922B: Swift-BAT refined analysis
  69. GRB050922C: optical observations
  70. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  71. GRB 050922C: optical obserations
  72. GRB 050922C: NOT optical observations
  73. GRB 050922A: Analysis of Swift/XRT TOO observation
  74. GRB 050922C: Swift detection of a bright burst
  75. GRB 050922C: ROTSE-IIId Refined Analysis
  76. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  77. GRB 050922B: ROTSE-III Optical Limits
  78. GRB 050922B,optical observation
  79. GRB050922B: Swift-BAT detection of a weak long burst
  80. Possible GRB 050922 detected by INTEGRAL
  81. GRB050918: Possible Swift/XRT detected afterglow
  82. GRB050820B: analysis of the XMM-Newton observation
  83. GRB050916: Swift/UVOT Upper Limits
  84. GRB 050916: Swift-BAT refined analysis
  85. GRB 050918 - A long GRB detected by INTEGRAL
  86. GRB 050915a: Radio Observations
  87. Swift-BAT trigger 155764 is not a GRB
  88. Swift-BAT trigger 155764 is probably not a GRB
  89. Swift trigger 155764: bad XRT centroid
  90. Swift-BAT trigger 155535 is definitely not a GRB
  91. GRB050916 : Swift-XRT refined analysis
  92. GRB 050916: XRT position
  93. GRB 050915b, SMARTS optical/IR observations of the XRT position
  94. GRB 050915B: Swift-BAT refined analysis
  95. GRB 050915B: Swift/UVOT Upper Limits
  96. GRB050916: Swift-BAT detection of a long weak burst
  97. GRB 050915a: IR Transient
  98. GRB 050915B: XRT position
  99. GRB 050915b, SMARTS optical/IR observations
  100. GRB050915B: Swift-BAT detection of a long bright burst

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