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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"

19412 results found.

  1. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  2. GRB 051012: Swift-BAT detection of burst yesterday
  3. Swift trigger 159578 is not a burst
  4. Swift-BAT Trigger 159578 is a possible burst
  5. GRB050805A: Rc optical observations
  6. GRB 051006: Swift/UVOT Upper Limits
  7. GRB 051008 - a low redshift low-luminosity burst?
  8. GRB051008: Swift XRT refined analysis
  9. GRB051008 - Swift UVOT upper limits
  10. Konus-Wind observation of GRB 051008
  11. GRB051008: Final refined analysis of the Swift-BAT burst
  12. GRB 051008: R-band upper limit
  13. GRB051008: Refined analysis of the Swift-BAT burst
  14. GRB 051008: Swift XRT position
  15. GRB 051008: early Swift XRT analysis
  16. GRB 051008: Swift UVOT Candidate
  17. GRB051008: Swift-BAT detection of a bright burst
  18. GRB 051006: XRT refined analysis
  19. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  20. GRB 051006: optical observations at Sierra Nevada
  21. GRB051006: Refined analysis of the Swift-BAT burst
  22. GRB 051006: XRT position
  23. GRB051006: Swift detection of a burst
  24. Swift-BAT triggers 158261 and 158262 Retraction
  25. GRB051001: Swift UVOT Upper Limits
  26. GRB 050925: Second Epoch WSRT Radio Observations
  27. GRB 051001: Swift XRT refined analysis
  28. GRB 051001, optical observations at Mt. John
  29. GRB 051001: I-band limit
  30. GRB 051001: Swift-BAT refined analysis
  31. GRB 051001: Swift Detection of a Burst
  32. GRB 051001: ROTSE-III Optical Limits
  33. GRB050922B: optical limit
  34. GRB050925: Swift/XRT limits
  35. GRB/SGR 050925: IR Observations
  36. GRB050922C - Swift UVOT preliminary analysis
  37. GRB 050925: WSRT Radio Observations
  38. GRB050925: Swift UVOT upper limits
  39. Refined analysis of the Swift-BAT soft short burst
  40. GRB050925: Faulkes Telescope North R-band limit
  41. GRB050925: Swift-BAT detection of a short burst
  42. GRB 050922B: Correction to BAT refined analysis, longer burst
  43. GRB050922B: refined XRT analysis
  44. Konus-Wind observation of GRB 050922C
  45. GRB050922B: Swift UVOT early upper limits.
  46. GRB 050922B: optical limit
  47. GRB 050922C: Swift XRT refined analysis
  48. HETE Fregate observations of GRB 050922C
  49. GRB 050922C: Swift-BAT refined analysis
  50. GRB 050922B: Swift-BAT refined analysis
  51. GRB050922C: optical observations
  52. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  53. GRB 050922C: optical obserations
  54. GRB 050922C: NOT optical observations
  55. GRB 050922A: Analysis of Swift/XRT TOO observation
  56. GRB 050922C: Swift detection of a bright burst
  57. GRB 050922C: ROTSE-IIId Refined Analysis
  58. GRB 050922C: ROTSE-III Detection of Possible Counterpart
  59. GRB 050922B: ROTSE-III Optical Limits
  60. GRB 050922B,optical observation
  61. GRB050922B: Swift-BAT detection of a weak long burst
  62. GRB050918: Possible Swift/XRT detected afterglow
  63. GRB050820B: analysis of the XMM-Newton observation
  64. GRB050916: Swift/UVOT Upper Limits
  65. GRB 050916: Swift-BAT refined analysis
  66. Swift-BAT trigger 155764 is not a GRB
  67. Swift-BAT trigger 155764 is probably not a GRB
  68. Swift trigger 155764: bad XRT centroid
  69. Swift-BAT trigger 155535 is definitely not a GRB
  70. GRB050916 : Swift-XRT refined analysis
  71. GRB 050916: XRT position
  72. GRB 050915B: Swift-BAT refined analysis
  73. GRB 050915B: Swift/UVOT Upper Limits
  74. GRB050916: Swift-BAT detection of a long weak burst
  75. GRB 050915B: XRT position
  76. GRB050915B: Swift-BAT detection of a long bright burst
  77. GRB050915: Swift/UVOT upper limits
  78. GRB 050915: KAIT optical limit
  79. GRB 050915: IR Observations
  80. GRB 050915: Swift XRT refined analysis
  81. GRB 050915: Swift-BAT refined analysis
  82. GRB050915, optical observations
  83. GRB050915: XRT position
  84. GRB 050915: ROTSE-III optical limits
  85. GRB 050915: Swift detection of a GRB
  86. GRB050911: Upper limit on X-ray afterglow
  87. Swift-BAT trigger 155072 ground analysis
  88. Swift-BAT trigger 155072 is probably not a GRB
  89. GRB050914: XRT position probably due to cosmic ray
  90. Swift is in normal operation
  91. GRB050911: Swift UVOT followup observations
  92. GRB 050911, optical content of Swift/XRT error box
  93. GRB050911: Swift-XRT position
  94. GRB 050911, optical observations
  95. GRB 050911: Swift-BAT refined analysis
  96. Later Swift-BAT triggers 154632 and 154633 RETRACTION
  97. GRB050911: Swift-BAT detection of a long burst
  98. GRB050908: detection of Swift/UVOT optical counterpart
  99. RBO GRB 050908 observations
  100. WIRO observations in I of GRB 050908

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