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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"

21468 results found.

  1. XRT observations of GRB 051105A
  2. GRB 051105: Swift-BAT improved refined analysis
  3. GRB 051105: Swift-BAT refined analysis
  4. GRB 051105: Swift detection of a short burst
  5. GRB 051022: RTT150 optical observations
  6. GRB051028: Swift/UVOT upper limits
  7. GRB051028: WHT optical candidate
  8. GRB051028: Swift XRT Position
  9. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  10. GRB051022: Swift XRT measurement of jet break
  11. GRB051021B: Swift/UVOT Upper limits
  12. GRB 051022: XRT Refined Spectral and Temporal Analysis
  13. GRB051012: Swift-XRT analysis
  14. GRB051021B: Swift XRT refined analysis
  15. GRB 051022: WSRT Radio Detection
  16. GRB051022: host galaxy redshift
  17. GRB 051022: Swift/UVOT Upper Limits
  18. GRB051022: IR observations
  19. GRB 051022: SOAR JKs Observations
  20. GRB051021A: Swift XRT refined analysis
  21. GRB051022: Optical Observations
  22. GRB 051022: Magellan NIR imaging
  23. GRB051021b: Magellan IR Imaging
  24. GRB 051022, J & K-band observation
  25. GRB051022: Swift XRT Position
  26. GRB051021: Swift/UVOT Upper Limits
  27. GRB 051021B: Refined analysis of the Swift-BAT burst
  28. GRB051021B: Swift XRT Position
  29. GRB 051021B: Swift detection of a burst
  30. GRB051021: Swift XRT analysis
  31. GRB051021.63
  32. Swift-BAT trigger 160640 is not a real GRB
  33. Swift-BAT trigger 160619 is not a GRB
  34. Swift-BAT triggered on a posible CR Shower or possible GRB
  35. GRB 051016b: Gemini Near IR Observations
  36. GRB 051016A: Swift/UVOT upper limits
  37. GRB 051016B: refined analysis of the Swift/XRT data
  38. GRB 051016B: Swift/UVOT detection
  39. GRB 051016B : Optical follow-up at Lulin
  40. GRB 051016B: Refined analysis of the Swift-BAT burst
  41. GRB 051016B: Swift detection of a soft burst
  42. GRB 051016: Swift-BAT refined analysis
  43. GRB051016 XMM-Newton observation
  44. GRB051016: Swift XRT refined analysis.
  45. GRB 051016: LCO optical and near-IR imaging
  46. GRB 051016: PROMPT Observations
  47. GRB051016: Swift detection of a burst
  48. Photometric calibration of Swift/UVOT and Re-analysis of Swift/UVOT GRB 050922C data
  49. GRB051006: optical observations
  50. GRB 051012: Swift-BAT detection of burst yesterday
  51. Swift trigger 159578 is not a burst
  52. Swift-BAT Trigger 159578 is a possible burst
  53. GRB050805A: Rc optical observations
  54. GRB 051006: Swift/UVOT Upper Limits
  55. GRB051008: optical candidate
  56. GRB 051008 - a low redshift low-luminosity burst?
  57. GRB051008: optical observation
  58. GRB051008: Swift XRT refined analysis
  59. GRB051008 - Swift UVOT upper limits
  60. Konus-Wind observation of GRB 051008
  61. GRB051008: Final refined analysis of the Swift-BAT burst
  62. GRB 051008: R-band upper limit
  63. GRB051008: Refined analysis of the Swift-BAT burst
  64. GRB051008: Radio Observation
  65. GRB 051008: Swift XRT position
  66. GRB 051008: early Swift XRT analysis
  67. GRB 051008: Swift UVOT Candidate
  68. GRB051008: Swift-BAT detection of a bright burst
  69. GRB 051006: P60 Observations
  70. GRB 051006: XRT refined analysis
  71. Swift-BAT trigger 158700 is a probable Cosmic Ray Shower Event
  72. GRB 051006: optical observations at Sierra Nevada
  73. GRB051006: Refined analysis of the Swift-BAT burst
  74. GRB 051006: XRT position
  75. GRB051006: Swift detection of a burst
  76. GRB 050906, summary of radio observations
  77. Swift-BAT triggers 158261 and 158262 Retraction
  78. GRB051001: Swift UVOT Upper Limits
  79. GRB 050925: Second Epoch WSRT Radio Observations
  80. GRB 051001: Swift XRT refined analysis
  81. GRB 051001, optical observations at Mt. John
  82. GRB 051001: I-band limit
  83. GRB 051001: AAT infra-red observations
  84. GRB 051001: Swift-BAT refined analysis
  85. GRB 051001: Swift Detection of a Burst
  86. GRB 051001: ROTSE-III Optical Limits
  87. GRB050922B: optical limit
  88. GRB050925: Swift/XRT limits
  89. GRB/SGR 050925: IR Observations
  90. GRB050922C - Swift UVOT preliminary analysis
  91. GRB 050925: WSRT Radio Observations
  92. GRB050925: Swift UVOT upper limits
  93. Refined analysis of the Swift-BAT soft short burst
  94. GRB050925: Faulkes Telescope North R-band limit
  95. GRB050925: Swift-BAT detection of a short burst
  96. GRB 050922B: Correction to BAT refined analysis, longer burst
  97. GRB050922B: refined XRT analysis
  98. Konus-Wind observation of GRB 050922C
  99. GRB050922B: Swift UVOT early upper limits.
  100. INT 2.5m limit for GRB050922B

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