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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"
  1. GRB 051210: SALT detection limit
  2. GRB 051210: BAT further refined analysis of the short burst
  3. GRB 051210: Swift XRT refined analysis
  4. GRB 051210: FRAM early limit
  5. GRB 051210: Swift-BAT refined analysis of a short burst
  6. GRB051210: Swift UVOT Observation
  7. GRB 051210: A short GRB in a cluster?
  8. GRB 051210: Swift detection of a burst
  9. IPN observations of SGR1806-20
  10. Swift XRT positions
  11. An extraordinary long burst on December 3 from SGR1806-20
  12. IBAS Alert 2706 : not a real GRB
  13. Possible resuming of the SGR 1806-20 activity
  14. Swift UVOT Calibration Documentation
  15. GRB051117B: optical observation
  16. GRB051111: optical observaion
  17. Swift-BAT trigger 165579 is not a GRB
  18. GRB 051127: Swift-BAT detection of a possible burst
  19. GRB051117B: Swift XRT refined analysis
  20. GRB051117b: No Swift/UVOT Detection
  21. GRB051111: Rc optical observations: correction
  22. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  23. GRB 051117A: Swift/UVOT Detection of an Afterglow
  24. GRB051111: Suzaku WAM observation of the prompt emission
  25. GRB051111: Rc optical observations
  26. GRB051008: Suzaku WAM observation of the prompt emission
  27. GRB 051109B: GAO 150cm telescope Optical limit
  28. GRB 051109A : GAO 150cm telescope Rc-band detection
  29. GRB 051021 Optical Observations
  30. GRB 051117B: MARGE Optical Limits
  31. GRB 051117A and B: Radio Observations
  32. GRB 051117B: R and I observations of possible host galaxy
  33. GRB 051117b: NIR observations
  34. GRB 051117A: Refined analysis of the Swift-BAT burst
  35. GRB 051117B: Refined analysis of the Swift-BAT burst
  36. GRB051117A : XRT refined analysis
  37. GRB 051117B,optical observation
  38. GRB 051117B: Lulin R and I band observation
  39. GRB 051117B: Optical observations
  40. GRB 051117B: ROTSE-III Optical Limits
  41. GRB051117B: Swift XRT position
  42. GRB 051117B: Swift detection of a burst
  43. GRB 051117: Swift detection of a bright burst
  44. GRB051114: results of the Swift-XRT observation
  45. GRB 051028 Optical Observations
  46. GRB 051109B : Nainital upper limits
  47. GRB 051114: Radio Observations
  48. GRB 051114: Swift-BAT refined analysis
  49. GRB050925: analysis of the XMM-Newton observation
  50. GRB051109A optical observations
  51. GRB 051114: Swift-BAT detection of a short burst
  52. GRB 051111: Further spectroscopic analysis
  53. GRB 051111: Radio afterglow
  54. GRB 051113: Swift-BAT refined analysis
  55. GRB 051113: Swift-BAT detection of a burst
  56. GRB 051111: AEOS optical observations
  57. GRB051103: Radio Observations
  58. GRB 051109A Milagro GeV/TeV Observations
  59. GRB/SGR 050925: XMM-Newton ToO observation
  60. GRB051111: Swift/UVOT Observations
  61. GRB 051111A : R-band temporal decay index based on Lulin
  62. GRB051111: XRT preliminary analysis
  63. GRB 051111: Swift-BAT refined analysis
  64. GRB 051109A Optical Observations
  65. GRB 051111A : Lulin BVRI multi band afterglow observation
  66. GRB051111a: SARA Observations
  67. GRB 051111a: IR photometry
  68. GRB 051111: Keck HIRES redshift
  69. GRB 051111A: KAIT optical observations
  70. GRB 051111a: Afterglow fading in Ic
  71. GRB051111: Super-LOTIS Early Detection
  72. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  73. Faulkes Telescope R-band detection of GRB051111
  74. GRB 051103 Milagro GeV/TeV Observations
  75. GRB051111: Swift-BAT detection of a bright burst
  76. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  77. GRB 051008 Tautenburg Supernova Search
  78. GRB 051109B. Radio Observations
  79. GRB 051109A
  80. GRB051109A - radio observations
  81. GRB 051105a: GETS optical limit
  82. GRB 051109b: GETS observation
  83. GRB 051109A: KAIT optical observations
  84. Early RAPTOR measurements of GRB 051109a - the movie.
  85. Konus-Wind observation of GRB 051109A
  86. GRB 051109B: Swift-BAT refined analysis
  87. GRB 051109B: ROTSE-III Optical Limits
  88. GRB 051109A: Swift-UVOT Observations
  89. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  90. GRB051109B: no UVOT source detected
  91. GRB051109B: XRT refined analysis
  92. GRB 051109B : Lulin Optical Observations
  93. GRB 051109A : Lulin BVRI Optical afterglow observation
  94. GRB051109A: further steepening in the X-ray light curve
  95. GRB051109A: XRT refined analysis
  96. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  97. GRB051109B: XRT position
  98. GRB 051109B: Super-LOTIS Observations
  99. GRB 051109B Kiso optical follow-up observation
  100. GRB051105B: REM Optical observation

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