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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"

31727 results found.

  1. GRB 051227: XRT refined analysis
  2. GRB 051227: Refined analysis of the Swift-BAT burst
  3. GRB 051227, optical observation
  4. GRB051117B: optical observation
  5. Konus-Wind observation of GRB 051221A
  6. GRB 051221A: MDM Optical Observations
  7. GRB 051221A: Detection at 251nm with Swift UVOT
  8. GRB 051221A: Chandra Afterglow Position
  9. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  10. GRB 051221B: ROTSE-III Optical Limits
  11. GRB 051221B: TAROT optical limits
  12. GRB 051221A: WSRT Radio Observations
  13. GRB 051221: Redshift from Gemini
  14. GRB 051221: Continued fading of optical afterglow
  15. GRB 051221B: Refined analysis of the Swift-BAT burst
  16. Possible GRB 051221B: MDM Optical Detection
  17. GRB 051221A: RAPTOR Fading Counterpart Constraint
  18. Possible GRB 051221B: Swift XRT position
  19. GRB 051221: Discovery of fading optical afterglow
  20. GRB 051221: Swift XRT refined analysis
  21. GRB 051221: Swift/UVOT upper limits
  22. GRB 051221: Possible nearby cluster
  23. GRB 051221: Correction to GCN #4368
  24. GRB 051221: Gemini observations
  25. GRB 051221: Improved astrometry of the IR counterpart
  26. GRB051221: K-band source
  27. GRB 051221: XRT position
  28. GRB 051221: Refined analysis of the Swift-BAT short hard burst
  29. GRB 051221: IR Observations at GRB+1hr
  30. Refined analysis of the SWIFT J1626.6-5156
  31. Refined analysis of the Swift-BAT detection of the RS CVn star II Peg
  32. GRB051211A (=H3979): Refined Analysis
  33. GRB 051211B: optical afterglow
  34. GRB051211A: possible optical candidate
  35. Swift Trigger 172767 is not a GRB
  36. GRB 051215: near-infrared observations
  37. GRB051215 - SDSS pre-burst observations
  38. GRB 051215: A short GRB in a cluster?
  39. GRB051211B: Probable radio afterglow
  40. GRB051105: optical observations
  41. GRB 051213: Swift-BAT refined analysis
  42. GRB051211B: XRT refined analysis
  43. GRB051211B, RBO optical observations
  44. GRB 051211A: Swift/UVOT upper limits
  45. GRB 051211B: Swift/UVOT upper limits - correction
  46. GRB 051211B: Swift/UVOT upper limits
  47. GRB 051211A,optical observation
  48. GRB 051211B: Swift XRT confirmation of the afterglow
  49. GRB051211B: Liverpool Telescope observation
  50. GRB 051211b: RTT150 optical observations
  51. GRB051211b: P60 Observations
  52. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  53. GRB 051211B: Swift XRT Observations
  54. GRB 051210: Swift/UVOT upper limits
  55. GRB 051210: Magellan Imaging
  56. GRB 051211: TAROT optical limits
  57. GRB 051211B: a possible optical detection by TAROT
  58. GRB 051211: Swift XRT upper limit
  59. HETE SXC localization of GRB 051211 (=H3979)
  60. GRB 051210: SALT detection limit
  61. GRB 051210: Swift XRT refined analysis
  62. GRB 051210: FRAM early limit
  63. GRB 051210: Swift-BAT refined analysis of a short burst
  64. GRB051210: Swift UVOT Observation
  65. GRB 051210: A short GRB in a cluster?
  66. IPN observations of SGR1806-20
  67. Swift XRT positions
  68. An extraordinary long burst on December 3 from SGR1806-20
  69. GRB051117B: optical observation
  70. GRB051111: optical observaion
  71. Swift-BAT trigger 165579 is not a GRB
  72. GRB051117b: No Swift/UVOT Detection
  73. GRB051111: Rc optical observations: correction
  74. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  75. GRB 051117A: Swift/UVOT Detection of an Afterglow
  76. GRB051111: Rc optical observations
  77. GRB051008: Suzaku WAM observation of the prompt emission
  78. GRB 051109B: GAO 150cm telescope Optical limit
  79. GRB 051109A : GAO 150cm telescope Rc-band detection
  80. GRB 051021 Optical Observations
  81. GRB 051117B: MARGE Optical Limits
  82. GRB 051117A and B: Radio Observations
  83. GRB 051117B: R and I observations of possible host galaxy
  84. GRB 051117b: NIR observations
  85. GRB 051117A: Refined analysis of the Swift-BAT burst
  86. GRB 051117B: Refined analysis of the Swift-BAT burst
  87. GRB051117A : XRT refined analysis
  88. GRB 051117B: Lulin R and I band observation
  89. GRB 051117B: Optical observations
  90. GRB 051117B: ROTSE-III Optical Limits
  91. GRB051114: results of the Swift-XRT observation
  92. GRB 051028 Optical Observations
  93. GRB 051109B : Nainital upper limits
  94. GRB 051114: Radio Observations
  95. GRB 051114: Swift-BAT refined analysis
  96. GRB 051114: Swift-BAT detection of a short burst
  97. GRB 051111: Further spectroscopic analysis
  98. GRB 051111: Radio afterglow
  99. GRB 051113: Swift-BAT refined analysis
  100. GRB051103: Radio Observations

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