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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"

35989 results found.

  1. GRB 051008: R-band upper limit
  2. GRB051008: Radio Observation
  3. GRB 051008: Swift XRT position
  4. GRB 051008, optical observations
  5. GRB 051008: early Swift XRT analysis
  6. GRB 051008: Swift UVOT Candidate
  7. GRB 051006: P60 Observations
  8. grb test
  9. GRB 051006: XRT refined analysis
  10. GRB 051006: optical observations at Sierra Nevada
  11. GRB 051006: XRT position
  12. GRB 050906, summary of radio observations
  13. GRB 050925: Second Epoch WSRT Radio Observations
  14. GRB 051001: Swift XRT refined analysis
  15. GRB 051001, optical observations at Mt. John
  16. GRB 051001: I-band limit
  17. GRB 051001: AAT infra-red observations
  18. GRB 051001: Swift-BAT refined analysis
  19. GRB 051001: Swift Detection of a Burst
  20. GRB 051001: ROTSE-III Optical Limits
  21. GRB050908: optical observations
  22. GRB050922C: optical observation
  23. GRB050922B: optical limit
  24. GRB 050922C: further VLT observations
  25. GRB 050820A: NIR photometry at the TNG
  26. GRB050922C: UVES/VLT high resolution spectroscopy
  27. GRB050925: Swift/XRT limits
  28. GRB/SGR 050925: IR Observations
  29. GRB 050922C: break in the lightcurve
  30. GRB 050925: WSRT Radio Observations
  31. GRB 050925 : I-band observation at Xinglong observatory
  32. GRB050925: Faulkes Telescope North R-band limit
  33. GRB050925: Swift-BAT detection of a short burst
  34. GRB 050922B: Correction to BAT refined analysis, longer burst
  35. GRB050922C: TNG spectroscopic observations
  36. GRB050922B: refined XRT analysis
  37. Konus-Wind observation of GRB 050922C
  38. GRB 050922C: Refined redshift
  39. GRB OT observation
  40. GRB050922C: observation at MonteBoo
  41. INT 2.5m limit for GRB050922B
  42. GRB 050922B: optical limit
  43. GRB050922C: Optical Observations
  44. GRB 050922C: Swift XRT refined analysis
  45. HETE Fregate observations of GRB 050922C
  46. GRB 050922C: Swift-BAT refined analysis
  47. GRB 050922B: Swift-BAT refined analysis
  48. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  49. GRB 050922C: optical obserations
  50. GRB 050922C: NOT optical observations
  51. GRB 050922A: Analysis of Swift/XRT TOO observation
  52. GRB 050922C: Swift detection of a bright burst
  53. GRB 050922C: ROTSE-IIId Refined Analysis
  54. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  55. GRB 050922B: ROTSE-III Optical Limits
  56. GRB 050922B,optical observation
  57. GRB050922B: Swift-BAT detection of a weak long burst
  58. Possible GRB 050922 detected by INTEGRAL
  59. GRB050820B: analysis of the XMM-Newton observation
  60. GRB050916: Swift/UVOT Upper Limits
  61. GRB 050916: Swift-BAT refined analysis
  62. GRB 050918 - A long GRB detected by INTEGRAL
  63. GRB 050915a: Radio Observations
  64. Swift-BAT trigger 155764 is not a GRB
  65. Swift-BAT trigger 155764 is probably not a GRB
  66. Swift-BAT trigger 155535 is definitely not a GRB
  67. GRB 050916: XRT position
  68. GRB 050915b, SMARTS optical/IR observations of the XRT position
  69. GRB 050915B: Swift-BAT refined analysis
  70. GRB 050915B: Swift/UVOT Upper Limits
  71. GRB 050915a: IR Transient
  72. GRB 050915B: XRT position
  73. GRB 050915b, SMARTS optical/IR observations
  74. GRB 050915: KAIT optical limit
  75. GRB 050915: IR Observations
  76. GRB 050915: Swift XRT refined analysis
  77. GRB 050915: Swift-BAT refined analysis
  78. GRB050915: P60 Optical Observations
  79. GRB 050915: ROTSE-III optical limits
  80. GRB 050915: Swift detection of a GRB
  81. GRB050911: Upper limit on X-ray afterglow
  82. Swift-BAT trigger 155072 ground analysis
  83. Swift-BAT trigger 155072 is probably not a GRB
  84. GRB 050911: LCO limits on a variable source
  85. GRB 050908: DEIMOS spectrum and further analysis
  86. Swift is in normal operation
  87. GRB 050911, optical content of Swift/XRT error box
  88. GRB 050911: LCO observations
  89. GRB 050911, optical observations
  90. GRB 050911: Swift-BAT refined analysis
  91. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  92. GRB 050911: z~0.16 cluster in the field
  93. GRB 050910a: TAROT early optical limits
  94. RBO GRB 050908 observations
  95. WIRO observations in I of GRB 050908
  96. GRB 050906: Possible X-ray Counterpart
  97. GRB 050906: RTT150 optical observations
  98. GRB050908: VLT R-band decay index.
  99. GRB 050908: Swift-BAT refined analysis
  100. GRB 050908: Optical observations

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