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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"

21459 results found.

  1. GRB 060110: Swift-BAT detection of a burst
  2. GRB 060109: Refined Swift-XRT analysis
  3. GRB 060109: Swift/UVOT upper limits
  4. GRB 060108: ISAS early observations and near IR upper limit
  5. GRB060108: P200 Ks Observations
  6. GRB 060108: early UKIRT K-band observations
  7. Swift UVOT correction to GCN 4455
  8. GRB 060109: Swift Detection of a long burst
  9. GRB 060108: a dark burst?
  10. GRB 060108: Refined XRT analysis
  11. GRB 060108: VLT J-band observations
  12. GRB 060108: Mitsume optical observations
  13. GRB 060108: Swift/UVOT upper limits
  14. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  15. GRB060108: Faulkes Telescope observation
  16. GRB 060108: Refined analysis of the Swift-BAT burst
  17. GRB 060108: Swift XRT position
  18. GRB060108: Swift detection of its 100th GRB
  19. GRB 060105: Radio observations
  20. GRB 060105: MDM Observation
  21. Konus-Wind observation of GRB 060105
  22. GRB 060105: ISAS observations and near IR upper limit
  23. GRB 060105: Swift/UVOT upper limits
  24. GRB 060105: Mitsume optical observations
  25. GRB 060105: BAT refined analysis
  26. GRB 060102 - no XRT afterglow
  27. GRB 060105: XRT refined analysis
  28. GRB060105: Swift detection of a bright long burst
  29. Swift-BAT trigger 175653 is not an astrophysical source
  30. Swift-BAT trigger 175653 is probably not a GRB
  31. GRB 060102: Swift-BAT refined analysis
  32. Time Correction to GRB 060102
  33. GRB 060102: Swift-BAT detection of a burst
  34. GRB051211B: optical observations
  35. GRB051227: SARA Observations
  36. GRB 051221B: Optical Observations with Kuiper 1.54m
  37. GRB051221B: Radio observations
  38. GRB051227: Radio Observations
  39. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  40. GRB 051227: Gemini observations
  41. GRB 051227: Keck Spectroscopy
  42. GRB 051227: Magellan r'-band Imaging/Astrometry
  43. GRB 051227: refined analysis of VLT images
  44. GRB 051227: P60 Observations
  45. GRB 051227: MDM Observation
  46. GRB 051227: R-band object in the XRT error circle
  47. GRB 051227: Joint Swift-HETE Spectral Analysis
  48. GRB 051227: XRT refined analysis
  49. GRB 051227: Further analysis of the Swift-BAT burst
  50. GRB 051227: Refined analysis of the Swift-BAT burst
  51. GRB051227: SDSS pre-burst observations
  52. GRB 051227: Swift detection of a burst
  53. Konus-Wind observation of GRB 051221A
  54. GRB051221A: Suzaku WAM observation of the prompt emission
  55. GRB051016: analysis of the XMM-Newton observation
  56. GRB 051221A: Detection at 251nm with Swift UVOT
  57. GRB 051221A: Chandra Afterglow Position
  58. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  59. GRB 051221B: ROTSE-III Optical Limits
  60. GRB 051221B: TAROT optical limits
  61. GRB 051221A: WSRT Radio Observations
  62. GRB 051221B: Refined analysis of the Swift-BAT burst
  63. Possible GRB 051221B: MDM Optical Detection
  64. GRB 051221A: RAPTOR Fading Counterpart Constraint
  65. GRB 051221B: BOOTES optical observations.
  66. Possible GRB 051221B: Swift XRT position
  67. Swift-BAT detection of a possible burst
  68. GRB 051221: Discovery of fading optical afterglow
  69. GRB 051221: Swift XRT refined analysis
  70. GRB 051221: Swift/UVOT upper limits
  71. GRB 051221: No variability in Gemini data
  72. GRB 051221: Gemini observations
  73. GRB 051221: Improved astrometry of the IR counterpart
  74. GRB051221: K-band source
  75. GRB 051221: XRT position
  76. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  77. GRB 051221: Swift detection of a bright short burst
  78. Refined analysis of the SWIFT J1626.6-5156
  79. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  80. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  81. GRB 051211B: optical afterglow
  82. Swift detection of an RS CVn flare star
  83. Swift Trigger 172767 is not a GRB
  84. GRB 051215: Swift detection of a possible burst
  85. GRB 051215: A short GRB in a cluster?
  86. GRB051211B: Probable radio afterglow
  87. GRB051105: optical observations
  88. GRB 051213: Swift-BAT refined analysis
  89. GRB051211B: XRT refined analysis
  90. GRB 051213: Swift-BAT detection of a burst
  91. GRB 051211A: Swift/UVOT upper limits
  92. GRB 051211B: Swift/UVOT upper limits - correction
  93. GRB 051211B: Swift/UVOT upper limits
  94. GRB 051211B: Swift XRT confirmation of the afterglow
  95. GRB051211B: Liverpool Telescope observation
  96. GRB 051211b: RTT150 optical observations
  97. GRB051211b: P60 Observations
  98. GRB 051211B: Swift XRT Observations
  99. GRB 051210: Swift/UVOT upper limits
  100. GRB 051211: Swift XRT upper limit

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