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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"

23416 results found.

  1. GRB051022: Swift XRT measurement of jet break
  2. GRB051021B: Swift/UVOT Upper limits
  3. GRB 051021, Optical Observations
  4. GRB051012: Swift-XRT analysis
  5. GRB 051022, mm counterpart
  6. GRB 051022: Swift/UVOT Upper Limits
  7. GRB051022: Radio Counterpart
  8. GRB051022: IR observations
  9. GRB051021A: Swift XRT refined analysis
  10. GRB051022: Optical Observations
  11. GRB 051021: PROMPT RcIc Observations
  12. GRB051021b: Magellan IR Imaging
  13. GRB051022: Swift XRT Position
  14. GRB 051021: P200 Ks Observations
  15. IPN triangulation of GRB051022 (=H3950)
  16. GRB 051022 (=H3950): SXC Flight Localization is Valid
  17. GRB051021: Swift/UVOT Upper Limits
  18. GRB 051021B: Refined analysis of the Swift-BAT burst
  19. GRB 051022: SSO40 Optical Observations
  20. GRB051022,optical observation
  21. GRB 051022A: ROTSE-III Optical Limits
  22. GRB 051021,optical observation
  23. GRB 051021B: Swift detection of a burst
  24. GRB051021: Swift XRT analysis
  25. Swift-BAT triggered on a posible CR Shower or possible GRB
  26. GRB 050502b: Optical limit
  27. Afterglow candidate of GRB 051016B observed at Lulin
  28. GRB 051016A: Swift/UVOT upper limits
  29. GRB 051016B: Swift/UVOT detection
  30. GRB 051016B,optical observation
  31. GRB 051016B : Optical follow-up at Lulin
  32. GRB 051016B: Swift detection of a soft burst
  33. GRB051016 XMM-Newton observation
  34. GRB 051016: LCO optical and near-IR imaging
  35. GRB 051016: PROMPT Observations
  36. GRB051016: Swift detection of a burst
  37. GRB051006: optical observations
  38. GRB 051012: Swift-BAT detection of burst yesterday
  39. Swift-BAT Trigger 159578 is a possible burst
  40. GRB050805A: Rc optical observations
  41. GRB 051006: Swift/UVOT Upper Limits
  42. GRB051008: optical candidate
  43. GRB 051008 - a low redshift low-luminosity burst?
  44. GRB051008: Swift XRT refined analysis
  45. GRB051008: Radio Observation
  46. GRB 051008, optical observations
  47. GRB 051008: early Swift XRT analysis
  48. GRB 051008: Swift UVOT Candidate
  49. GRB051008: Swift-BAT detection of a bright burst
  50. GRB 051006: P60 Observations
  51. GRB 051006: XRT refined analysis
  52. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  53. GRB 051006: optical observations at Sierra Nevada
  54. GRB051006: Refined analysis of the Swift-BAT burst
  55. GRB051006: Swift detection of a burst
  56. GRB 050906, summary of radio observations
  57. GRB051001: Swift UVOT Upper Limits
  58. GRB 050925: Second Epoch WSRT Radio Observations
  59. GRB 051001: AAT infra-red observations
  60. GRB 051001: Swift Detection of a Burst
  61. GRB 051001: ROTSE-III Optical Limits
  62. GRB 050820A: NIR photometry at the TNG
  63. GRB050925: Swift/XRT limits
  64. GRB/SGR 050925: IR Observations
  65. GRB 050925: WSRT Radio Observations
  66. GRB050925: Swift UVOT upper limits
  67. GRB 050925 : I-band observation at Xinglong observatory
  68. GRB050925: Faulkes Telescope North R-band limit
  69. GRB050925: Swift-BAT detection of a short burst
  70. GRB050922B: refined XRT analysis
  71. GRB050922B: Swift UVOT early upper limits.
  72. INT 2.5m limit for GRB050922B
  73. GRB 050922B: optical limit
  74. GRB 050922C: Swift-BAT refined analysis
  75. GRB 050922C: optical obserations
  76. GRB 050922C: NOT optical observations
  77. GRB 050922A: Analysis of Swift/XRT TOO observation
  78. GRB 050922C: Swift detection of a bright burst
  79. GRB 050922B: ROTSE-III Optical Limits
  80. GRB 050922B,optical observation
  81. GRB050922B: Swift-BAT detection of a weak long burst
  82. GRB050820B: analysis of the XMM-Newton observation
  83. GRB050916: Swift/UVOT Upper Limits
  84. GRB 050915a: Radio Observations
  85. Swift-BAT trigger 155764 is not a GRB
  86. Swift-BAT trigger 155764 is probably not a GRB
  87. Swift trigger 155764: bad XRT centroid
  88. Swift-BAT trigger 155535 is definitely not a GRB
  89. GRB050916 : Swift-XRT refined analysis
  90. GRB 050915B: Swift/UVOT Upper Limits
  91. GRB050916: Swift-BAT detection of a long weak burst
  92. GRB 050915a: IR Transient
  93. GRB 050915b, SMARTS optical/IR observations
  94. GRB050915B: Swift-BAT detection of a long bright burst
  95. GRB050915: Swift/UVOT upper limits
  96. GRB 050915: KAIT optical limit
  97. GRB 050915: IR Observations
  98. GRB 050915: Swift-BAT refined analysis
  99. GRB050915: P60 Optical Observations
  100. GRB 050915: ROTSE-III optical limits

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