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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 051117: Swift detection of a bright burst
  2. GRB051114: results of the Swift-XRT observation
  3. GRB 051028 Optical Observations
  4. GRB 051109B : Nainital upper limits
  5. GRB 051114: Radio Observations
  6. GRB 051114: Swift-BAT refined analysis
  7. GRB050925: analysis of the XMM-Newton observation
  8. GRB051109A optical observations
  9. GRB 051114: Swift-BAT detection of a short burst
  10. GRB 051111: Further spectroscopic analysis
  11. GRB 051111: Radio afterglow
  12. GRB 051113: Swift-BAT refined analysis
  13. GRB 051113: Swift-BAT detection of a burst
  14. GRB 051111: AEOS optical observations
  15. GRB051103: Radio Observations
  16. GRB 051109A Milagro GeV/TeV Observations
  17. GRB/SGR 050925: XMM-Newton ToO observation
  18. GRB051111: Swift/UVOT Observations
  19. GRB 051111A : R-band temporal decay index based on Lulin
  20. GRB051111: XRT preliminary analysis
  21. GRB 051111: Swift-BAT refined analysis
  22. GRB 051109A Optical Observations
  23. GRB 051111A : Lulin BVRI multi band afterglow observation
  24. GRB051111a: SARA Observations
  25. GRB 051111a: IR photometry
  26. GRB 051111: Keck HIRES redshift
  27. GRB 051111A: KAIT optical observations
  28. GRB 051111a: Afterglow fading in Ic
  29. GRB051111: Super-LOTIS Early Detection
  30. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  31. Faulkes Telescope R-band detection of GRB051111
  32. GRB 051103 Milagro GeV/TeV Observations
  33. GRB051111: Swift-BAT detection of a bright burst
  34. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  35. GRB 051008 Tautenburg Supernova Search
  36. GRB 051109B. Radio Observations
  37. GRB 051109A
  38. GRB051109A - radio observations
  39. GRB 051105a: GETS optical limit
  40. GRB 051109b: GETS observation
  41. GRB 051109A: KAIT optical observations
  42. Early RAPTOR measurements of GRB 051109a - the movie.
  43. Konus-Wind observation of GRB 051109A
  44. GRB 051109B: Swift-BAT refined analysis
  45. GRB 051109B: ROTSE-III Optical Limits
  46. GRB 051109A: Swift-UVOT Observations
  47. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  48. GRB051109B: no UVOT source detected
  49. GRB051109B: XRT refined analysis
  50. GRB 051109B : Lulin Optical Observations
  51. GRB 051109A : Lulin BVRI Optical afterglow observation
  52. GRB051109A: further steepening in the X-ray light curve
  53. GRB051109A: XRT refined analysis
  54. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  55. GRB051109B: XRT position
  56. GRB 051109B: Super-LOTIS Observations
  57. GRB 051109B Kiso optical follow-up observation
  58. GRB051105B: REM Optical observation
  59. GRB 051109B: Swift detection of a burst
  60. GRB 051109: HET Optical Spectrum and Absorption Redshift
  61. GRB 051109: PROMPT Detections
  62. GRB 051109: Rc and Ic observations
  63. GRB051109: Early Super-LOTIS Detection
  64. GRB 051109: Swift-BAT refined analysis
  65. GRB 051109a: IR Photometry and Astrometry
  66. GRB 051109a: MDM Observations
  67. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  68. GRB051109: Swift detection of a burst
  69. GRB 051109a: IR Detections
  70. GRB 051109: ROTSE-III Detection of Possible Counterpart
  71. GRB051105B: Swift/XRT upper limit
  72. GRB051105B: Swift/UVOT upper limit
  73. GRB051103: optical observations
  74. GRB 051103, optical observations
  75. GRB051103: MASTER: OT limit and host galaxy candidates
  76. GRB051028: Swift-XRT refined analysis
  77. GRB 051105a, observation from Naini Tal and OSN
  78. GRB 051105A, 2nd epoch optical observations
  79. GRB 051105a: MDM Observations
  80. GRB 051105A: TNG optical observations
  81. GRB051105A: Swift/UVOT Observations
  82. GRB 051105A, radio observations
  83. GRB051103:_MASTER_optical_observations
  84. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  85. GRB 051105A, optical observations
  86. XRT observations of GRB 051105A
  87. GRB 051105: Swift-BAT improved refined analysis
  88. GRB 051105b: ART optical limits
  89. GRB051105B - A long GRB detected by INTEGRAL
  90. GRB 051105B (INTEGRAL 2701): Optical observation
  91. GRB 051105: Swift-BAT refined analysis
  92. GRB 051105: Optical limit
  93. GRB 051105: Swift detection of a short burst
  94. IBAS Alert 2700: Not a GRB
  95. GRB 051016B host spectroscopy and redshift
  96. GRB051016B: optical observation
  97. Recent GRB UBVRcIc field photometry
  98. Konus-Wind observation of GRB 051028
  99. GRB051028:MASTER correction and final results
  100. GRB 051022: RTT150 optical observations

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