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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"

21455 results found.

  1. GRB051021B: Swift XRT refined analysis
  2. GRB 051022: WSRT Radio Detection
  3. GRB051022: host galaxy redshift
  4. GRB 051022: Swift/UVOT Upper Limits
  5. GRB051022: IR observations
  6. GRB 051022: SOAR JKs Observations
  7. GRB051021A: Swift XRT refined analysis
  8. GRB051022: Optical Observations
  9. GRB 051022: Magellan NIR imaging
  10. GRB051021b: Magellan IR Imaging
  11. GRB 051022, J & K-band observation
  12. GRB051022: Swift XRT Position
  13. GRB051021: Swift/UVOT Upper Limits
  14. GRB 051021B: Refined analysis of the Swift-BAT burst
  15. GRB051021B: Swift XRT Position
  16. GRB 051021B: Swift detection of a burst
  17. GRB051021: Swift XRT analysis
  18. GRB051021.63
  19. Swift-BAT trigger 160640 is not a real GRB
  20. Swift-BAT trigger 160619 is not a GRB
  21. Swift-BAT triggered on a posible CR Shower or possible GRB
  22. GRB 051016b: Gemini Near IR Observations
  23. GRB 051016A: Swift/UVOT upper limits
  24. GRB 051016B: refined analysis of the Swift/XRT data
  25. GRB 051016B: Swift/UVOT detection
  26. GRB 051016B : Optical follow-up at Lulin
  27. GRB 051016B: Refined analysis of the Swift-BAT burst
  28. GRB 051016B: Swift detection of a soft burst
  29. GRB 051016: Swift-BAT refined analysis
  30. GRB051016 XMM-Newton observation
  31. GRB051016: Swift XRT refined analysis.
  32. GRB 051016: LCO optical and near-IR imaging
  33. GRB 051016: PROMPT Observations
  34. GRB051016: Swift detection of a burst
  35. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  36. GRB051006: optical observations
  37. GRB 051012: Swift-BAT detection of burst yesterday
  38. Swift trigger 159578 is not a burst
  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: optical observation
  45. GRB051008: Swift XRT refined analysis
  46. GRB051008 - Swift UVOT upper limits
  47. Konus-Wind observation of GRB 051008
  48. GRB051008: Final refined analysis of the Swift-BAT burst
  49. GRB 051008: R-band upper limit
  50. GRB051008: Refined analysis of the Swift-BAT burst
  51. GRB051008: Radio Observation
  52. GRB 051008: Swift XRT position
  53. GRB 051008: early Swift XRT analysis
  54. GRB 051008: Swift UVOT Candidate
  55. GRB051008: Swift-BAT detection of a bright burst
  56. GRB 051006: P60 Observations
  57. GRB 051006: XRT refined analysis
  58. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  59. GRB 051006: optical observations at Sierra Nevada
  60. GRB051006: Refined analysis of the Swift-BAT burst
  61. GRB 051006: XRT position
  62. GRB051006: Swift detection of a burst
  63. GRB 050906, summary of radio observations
  64. Swift-BAT triggers 158261 and 158262 Retraction
  65. GRB051001: Swift UVOT Upper Limits
  66. GRB 050925: Second Epoch WSRT Radio Observations
  67. GRB 051001: Swift XRT refined analysis
  68. GRB 051001, optical observations at Mt. John
  69. GRB 051001: I-band limit
  70. GRB 051001: AAT infra-red observations
  71. GRB 051001: Swift-BAT refined analysis
  72. GRB 051001: Swift Detection of a Burst
  73. GRB 051001: ROTSE-III Optical Limits
  74. GRB050922B: optical limit
  75. GRB050925: Swift/XRT limits
  76. GRB/SGR 050925: IR Observations
  77. GRB050922C - Swift UVOT preliminary analysis
  78. GRB 050925: WSRT Radio Observations
  79. GRB050925: Swift UVOT upper limits
  80. Refined analysis of the Swift-BAT soft short burst
  81. GRB050925: Faulkes Telescope North R-band limit
  82. GRB050925: Swift-BAT detection of a short burst
  83. GRB 050922B: Correction to BAT refined analysis, longer burst
  84. GRB050922B: refined XRT analysis
  85. Konus-Wind observation of GRB 050922C
  86. GRB050922B: Swift UVOT early upper limits.
  87. INT 2.5m limit for GRB050922B
  88. GRB 050922B: optical limit
  89. GRB 050922C: Swift XRT refined analysis
  90. HETE Fregate observations of GRB 050922C
  91. GRB 050922C: Swift-BAT refined analysis
  92. GRB 050922B: Swift-BAT refined analysis
  93. GRB050922C: optical observations
  94. GRB 050922C: Absorption redshift from the Nordic Optical Telescope
  95. GRB 050922C: optical obserations
  96. GRB 050922C: NOT optical observations
  97. GRB 050922A: Analysis of Swift/XRT TOO observation
  98. GRB 050922C: Swift detection of a bright burst
  99. GRB 050922C: ROTSE-IIId Refined Analysis
  100. GRB 050922C: ROTSE-III Detection of Possible Counterpart

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