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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. Faulkes Telescope R-band detection of GRB051111
  2. GRB 051103 Milagro GeV/TeV Observations
  3. GRB051111: Swift-BAT detection of a bright burst
  4. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  5. GRB 051008 Tautenburg Supernova Search
  6. GRB 051109B. Radio Observations
  7. GRB 051109A
  8. GRB051109A - radio observations
  9. GRB 051105a: GETS optical limit
  10. GRB 051109b: GETS observation
  11. GRB 051109A: KAIT optical observations
  12. Early RAPTOR measurements of GRB 051109a - the movie.
  13. Konus-Wind observation of GRB 051109A
  14. GRB 051109B: Swift-BAT refined analysis
  15. GRB 051109B: ROTSE-III Optical Limits
  16. GRB 051109A: Swift-UVOT Observations
  17. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  18. GRB051109B: no UVOT source detected
  19. GRB051109B: XRT refined analysis
  20. GRB 051109B : Lulin Optical Observations
  21. GRB 051109A : Lulin BVRI Optical afterglow observation
  22. GRB051109A: further steepening in the X-ray light curve
  23. GRB051109A: XRT refined analysis
  24. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  25. GRB051109B: XRT position
  26. GRB 051109B: Super-LOTIS Observations
  27. GRB 051109B Kiso optical follow-up observation
  28. GRB051105B: REM Optical observation
  29. GRB 051109B: Swift detection of a burst
  30. GRB 051109: HET Optical Spectrum and Absorption Redshift
  31. GRB 051109: PROMPT Detections
  32. GRB 051109: Rc and Ic observations
  33. GRB051109: Early Super-LOTIS Detection
  34. GRB 051109: Swift-BAT refined analysis
  35. GRB 051109a: IR Photometry and Astrometry
  36. GRB 051109a: MDM Observations
  37. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  38. GRB051109: Swift detection of a burst
  39. GRB 051109a: IR Detections
  40. GRB 051109: ROTSE-III Detection of Possible Counterpart
  41. GRB051105B: Swift/XRT upper limit
  42. GRB051105B: Swift/UVOT upper limit
  43. GRB051103: optical observations
  44. GRB 051103, optical observations
  45. GRB051103: MASTER: OT limit and host galaxy candidates
  46. GRB051028: Swift-XRT refined analysis
  47. GRB 051105a, observation from Naini Tal and OSN
  48. GRB 051105A, 2nd epoch optical observations
  49. GRB 051105a: MDM Observations
  50. GRB 051105A: TNG optical observations
  51. GRB051105A: Swift/UVOT Observations
  52. GRB 051105A, radio observations
  53. GRB051103:_MASTER_optical_observations
  54. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  55. GRB 051105A, optical observations
  56. XRT observations of GRB 051105A
  57. GRB 051105: Swift-BAT improved refined analysis
  58. GRB 051105b: ART optical limits
  59. GRB051105B - A long GRB detected by INTEGRAL
  60. GRB 051105B (INTEGRAL 2701): Optical observation
  61. GRB 051105: Swift-BAT refined analysis
  62. GRB 051105: Optical limit
  63. GRB 051105: Swift detection of a short burst
  64. IBAS Alert 2700: Not a GRB
  65. GRB 051016B host spectroscopy and redshift
  66. GRB051016B: optical observation
  67. Recent GRB UBVRcIc field photometry
  68. Konus-Wind observation of GRB 051028
  69. GRB051028:MASTER correction and final results
  70. GRB 051022: RTT150 optical observations
  71. GRB 051021A: RTT150 optical observations
  72. GRB051028 SARA Observation
  73. GRB051028: optical observations
  74. GRB051028: Swift/UVOT upper limits
  75. GRB051028: confirmation of the afterglow
  76. GRB051028: WHT optical candidate
  77. GRB051028: Swift XRT Position
  78. GRB051028:MASTER observations
  79. GRB 051028 (=H3951): A GRB localized by HETE
  80. GRB051028:MASTER optical observations
  81. GRB 051022: XRT Refined Spectral and Temporal Analysis--Correction
  82. GRB051022: Swift XRT measurement of jet break
  83. SGR 1806-20: continued moderate activity seen with INTEGRAL
  84. GRB051021B: Swift/UVOT Upper limits
  85. GRB 051021, Optical Observations
  86. GRB 051022: XRT Refined Spectral and Temporal Analysis
  87. GRB 051022, refined optical astrometry
  88. Chandra Observations of GRB 051022
  89. GRB051012: Swift-XRT analysis
  90. GRB 051022 Chandra Observations scheduled
  91. GRB051021B: Swift XRT refined analysis
  92. GRB051021a: optical observations
  93. GRB 051022: WSRT Radio Detection
  94. GRB 051022, mm counterpart
  95. GRB051022: host galaxy redshift
  96. GRB 051022: Swift/UVOT Upper Limits
  97. GRB051022: Radio Counterpart
  98. GRB051022: IR observations
  99. GRB 051022: SOAR JKs Observations
  100. GRB051021A: Swift XRT refined analysis

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