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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"

23417 results found.

  1. GRB051028: Swift XRT Position
  2. GRB051022: Swift XRT measurement of jet break
  3. GRB051021B: Swift/UVOT Upper limits
  4. GRB 051021, Optical Observations
  5. GRB051012: Swift-XRT analysis
  6. GRB 051022, mm counterpart
  7. GRB 051022: Swift/UVOT Upper Limits
  8. GRB051022: Radio Counterpart
  9. GRB051022: IR observations
  10. GRB051021A: Swift XRT refined analysis
  11. GRB051022: Optical Observations
  12. GRB 051021: PROMPT RcIc Observations
  13. GRB051021b: Magellan IR Imaging
  14. GRB051022: Swift XRT Position
  15. GRB 051021: P200 Ks Observations
  16. IPN triangulation of GRB051022 (=H3950)
  17. GRB 051022 (=H3950): SXC Flight Localization is Valid
  18. GRB051021: Swift/UVOT Upper Limits
  19. GRB 051021B: Refined analysis of the Swift-BAT burst
  20. GRB 051022: SSO40 Optical Observations
  21. GRB051022,optical observation
  22. GRB 051022A: ROTSE-III Optical Limits
  23. GRB 051021,optical observation
  24. GRB 051021B: Swift detection of a burst
  25. GRB051021: Swift XRT analysis
  26. Swift-BAT triggered on a posible CR Shower or possible GRB
  27. GRB 050502b: Optical limit
  28. Afterglow candidate of GRB 051016B observed at Lulin
  29. GRB 051016A: Swift/UVOT upper limits
  30. GRB 051016B: Swift/UVOT detection
  31. GRB 051016B,optical observation
  32. GRB 051016B : Optical follow-up at Lulin
  33. GRB 051016B: Swift detection of a soft burst
  34. GRB051016 XMM-Newton observation
  35. GRB 051016: LCO optical and near-IR imaging
  36. GRB 051016: PROMPT Observations
  37. GRB051016: Swift detection of a burst
  38. GRB051006: optical observations
  39. GRB 051012: Swift-BAT detection of burst yesterday
  40. Swift-BAT Trigger 159578 is a possible burst
  41. GRB050805A: Rc optical observations
  42. GRB 051006: Swift/UVOT Upper Limits
  43. GRB051008: optical candidate
  44. GRB 051008 - a low redshift low-luminosity burst?
  45. GRB051008: Swift XRT refined analysis
  46. GRB051008: Radio Observation
  47. GRB 051008, optical observations
  48. GRB 051008: early Swift XRT analysis
  49. GRB 051008: Swift UVOT Candidate
  50. GRB051008: Swift-BAT detection of a bright burst
  51. GRB 051006: P60 Observations
  52. GRB 051006: XRT refined analysis
  53. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  54. GRB 051006: optical observations at Sierra Nevada
  55. GRB051006: Refined analysis of the Swift-BAT burst
  56. GRB051006: Swift detection of a burst
  57. GRB 050906, summary of radio observations
  58. GRB051001: Swift UVOT Upper Limits
  59. GRB 050925: Second Epoch WSRT Radio Observations
  60. GRB 051001: AAT infra-red observations
  61. GRB 051001: Swift Detection of a Burst
  62. GRB 051001: ROTSE-III Optical Limits
  63. GRB 050820A: NIR photometry at the TNG
  64. GRB050925: Swift/XRT limits
  65. GRB/SGR 050925: IR Observations
  66. GRB 050925: WSRT Radio Observations
  67. GRB050925: Swift UVOT upper limits
  68. GRB 050925 : I-band observation at Xinglong observatory
  69. GRB050925: Faulkes Telescope North R-band limit
  70. GRB050925: Swift-BAT detection of a short burst
  71. GRB050922B: refined XRT analysis
  72. GRB050922B: Swift UVOT early upper limits.
  73. INT 2.5m limit for GRB050922B
  74. GRB 050922B: optical limit
  75. GRB 050922C: Swift-BAT refined analysis
  76. GRB 050922C: optical obserations
  77. GRB 050922C: NOT optical observations
  78. GRB 050922A: Analysis of Swift/XRT TOO observation
  79. GRB 050922C: Swift detection of a bright burst
  80. GRB 050922B: ROTSE-III Optical Limits
  81. GRB 050922B,optical observation
  82. GRB050922B: Swift-BAT detection of a weak long burst
  83. GRB050820B: analysis of the XMM-Newton observation
  84. GRB050916: Swift/UVOT Upper Limits
  85. GRB 050915a: Radio Observations
  86. Swift-BAT trigger 155764 is not a GRB
  87. Swift-BAT trigger 155764 is probably not a GRB
  88. Swift trigger 155764: bad XRT centroid
  89. Swift-BAT trigger 155535 is definitely not a GRB
  90. GRB050916 : Swift-XRT refined analysis
  91. GRB 050915B: Swift/UVOT Upper Limits
  92. GRB050916: Swift-BAT detection of a long weak burst
  93. GRB 050915a: IR Transient
  94. GRB 050915b, SMARTS optical/IR observations
  95. GRB050915B: Swift-BAT detection of a long bright burst
  96. GRB050915: Swift/UVOT upper limits
  97. GRB 050915: KAIT optical limit
  98. GRB 050915: IR Observations
  99. GRB 050915: Swift-BAT refined analysis
  100. GRB050915: P60 Optical Observations

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