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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"

35982 results found.

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

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