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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"

18400 results found.

  1. GRB 060108: VLT J-band observations
  2. GRB 060108: Swift/UVOT upper limits
  3. GRB 060105: quick look analysis of the Suzaku/XIS afterglow observation
  4. GRB060108: Faulkes Telescope observation
  5. GRB 060108: Refined analysis of the Swift-BAT burst
  6. GRB 060108: Swift XRT position
  7. GRB060108: Swift detection of its 100th GRB
  8. GRB 060105: Radio observations
  9. Konus-Wind observation of GRB 060105
  10. GRB 060105: Swift/UVOT upper limits
  11. GRB 060105: BAT refined analysis
  12. GRB 060105: XRT refined analysis
  13. GRB060105: Swift detection of a bright long burst
  14. Swift-BAT trigger 175653 is not an astrophysical source
  15. Swift-BAT trigger 175653 is probably not a GRB
  16. GRB 060102: Swift-BAT refined analysis
  17. Time Correction to GRB 060102
  18. GRB 060102: Swift-BAT detection of a burst
  19. GRB051211B: optical observations
  20. GRB051227: SARA Observations
  21. GRB 051221B: Optical Observations with Kuiper 1.54m
  22. GRB051221B: Radio observations
  23. GRB051227: Radio Observations
  24. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  25. GRB 051227: MDM Observation
  26. GRB 051227: Joint Swift-HETE Spectral Analysis
  27. GRB 051227: XRT refined analysis
  28. GRB 051227: Further analysis of the Swift-BAT burst
  29. GRB 051227: Refined analysis of the Swift-BAT burst
  30. GRB051227: SDSS pre-burst observations
  31. GRB 051227: Swift detection of a burst
  32. Konus-Wind observation of GRB 051221A
  33. GRB051221A: Suzaku WAM observation of the prompt emission
  34. GRB051016: analysis of the XMM-Newton observation
  35. GRB 051221A: Detection at 251nm with Swift UVOT
  36. GRB 051221A: Chandra Afterglow Position
  37. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  38. GRB 051221B: ROTSE-III Optical Limits
  39. GRB 051221B: TAROT optical limits
  40. GRB 051221A: WSRT Radio Observations
  41. GRB 051221B: Refined analysis of the Swift-BAT burst
  42. Possible GRB 051221B: MDM Optical Detection
  43. GRB 051221A: RAPTOR Fading Counterpart Constraint
  44. GRB 051221B: BOOTES optical observations.
  45. Possible GRB 051221B: Swift XRT position
  46. Swift-BAT detection of a possible burst
  47. GRB 051221: Swift XRT refined analysis
  48. GRB 051221: Swift/UVOT upper limits
  49. GRB 051221: XRT position
  50. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  51. GRB 051221: Swift detection of a bright short burst
  52. Refined analysis of the SWIFT J1626.6-5156
  53. Swift-BAT discovery of hard x-ray transient SWIFT J1626.6-5156
  54. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  55. GRB 051211B: optical afterglow
  56. Swift detection of an RS CVn flare star
  57. Swift Trigger 172767 is not a GRB
  58. GRB 051215: Swift detection of a possible burst
  59. GRB 051215: A short GRB in a cluster?
  60. GRB 051213: Swift-BAT refined analysis
  61. GRB051211B: XRT refined analysis
  62. GRB 051213: Swift-BAT detection of a burst
  63. GRB 051211A: Swift/UVOT upper limits
  64. GRB 051211B: Swift/UVOT upper limits - correction
  65. GRB 051211B: Swift/UVOT upper limits
  66. GRB 051211B: Swift XRT confirmation of the afterglow
  67. GRB051211B: Liverpool Telescope observation
  68. GRB 051211B: Swift XRT Observations
  69. GRB 051210: Swift/UVOT upper limits
  70. GRB 051211: Swift XRT upper limit
  71. GRB 051210: SALT detection limit
  72. GRB 051210: BAT further refined analysis of the short burst
  73. GRB 051210: Swift XRT refined analysis
  74. GRB 051210: Swift-BAT refined analysis of a short burst
  75. GRB051210: Swift UVOT Observation
  76. GRB 051210: Swift detection of a burst
  77. IPN observations of SGR1806-20
  78. Swift XRT positions
  79. An extraordinary long burst on December 3 from SGR1806-20
  80. Swift UVOT Calibration Documentation
  81. Swift-BAT trigger 165579 is not a GRB
  82. GRB 051127: Swift-BAT detection of a possible burst
  83. GRB051117B: Swift XRT refined analysis
  84. GRB051117b: No Swift/UVOT Detection
  85. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  86. GRB 051117A: Swift/UVOT Detection of an Afterglow
  87. GRB051111: Rc optical observations
  88. GRB051008: Suzaku WAM observation of the prompt emission
  89. GRB 051117B: MARGE Optical Limits
  90. GRB 051117B: R and I observations of possible host galaxy
  91. GRB 051117A: Refined analysis of the Swift-BAT burst
  92. GRB 051117B: Refined analysis of the Swift-BAT burst
  93. GRB051117A : XRT refined analysis
  94. GRB 051117B,optical observation
  95. GRB 051117B: Lulin R and I band observation
  96. GRB 051117B: Optical observations
  97. GRB 051117B: ROTSE-III Optical Limits
  98. GRB051117B: Swift XRT position
  99. GRB 051117B: Swift detection of a burst
  100. GRB 051117: Swift detection of a bright burst

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