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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 051117B: R and I observations of possible host galaxy
  2. GRB 051117b: NIR observations
  3. GRB 051117A: Refined analysis of the Swift-BAT burst
  4. GRB 051117B: Refined analysis of the Swift-BAT burst
  5. GRB051117A : XRT refined analysis
  6. GRB 051117B,optical observation
  7. GRB 051117B: Lulin R and I band observation
  8. GRB 051117B: Optical observations
  9. GRB 051117B: ROTSE-III Optical Limits
  10. GRB051117B: Swift XRT position
  11. GRB 051117B: Swift detection of a burst
  12. GRB 051117: Swift detection of a bright burst
  13. GRB051114: results of the Swift-XRT observation
  14. GRB 051028 Optical Observations
  15. GRB 051109B : Nainital upper limits
  16. GRB 051114: Radio Observations
  17. GRB 051114: Swift-BAT refined analysis
  18. GRB050925: analysis of the XMM-Newton observation
  19. GRB051109A optical observations
  20. GRB 051114: Swift-BAT detection of a short burst
  21. GRB 051111: Further spectroscopic analysis
  22. GRB 051111: Radio afterglow
  23. GRB 051113: Swift-BAT refined analysis
  24. GRB 051113: Swift-BAT detection of a burst
  25. GRB 051111: AEOS optical observations
  26. GRB051103: Radio Observations
  27. GRB 051109A Milagro GeV/TeV Observations
  28. GRB/SGR 050925: XMM-Newton ToO observation
  29. GRB051111: Swift/UVOT Observations
  30. GRB 051111A : R-band temporal decay index based on Lulin
  31. GRB051111: XRT preliminary analysis
  32. GRB 051111: Swift-BAT refined analysis
  33. GRB 051109A Optical Observations
  34. GRB 051111A : Lulin BVRI multi band afterglow observation
  35. GRB051111a: SARA Observations
  36. GRB 051111a: IR photometry
  37. GRB 051111: Keck HIRES redshift
  38. GRB 051111A: KAIT optical observations
  39. GRB 051111a: Afterglow fading in Ic
  40. GRB051111: Super-LOTIS Early Detection
  41. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  42. Faulkes Telescope R-band detection of GRB051111
  43. GRB 051103 Milagro GeV/TeV Observations
  44. GRB051111: Swift-BAT detection of a bright burst
  45. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  46. GRB 051008 Tautenburg Supernova Search
  47. GRB 051109B. Radio Observations
  48. GRB 051109A
  49. GRB051109A - radio observations
  50. GRB 051105a: GETS optical limit
  51. GRB 051109b: GETS observation
  52. GRB 051109A: KAIT optical observations
  53. Early RAPTOR measurements of GRB 051109a - the movie.
  54. Konus-Wind observation of GRB 051109A
  55. GRB 051109B: Swift-BAT refined analysis
  56. GRB 051109B: ROTSE-III Optical Limits
  57. GRB 051109A: Swift-UVOT Observations
  58. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  59. GRB051109B: no UVOT source detected
  60. GRB051109B: XRT refined analysis
  61. GRB 051109B : Lulin Optical Observations
  62. GRB 051109A : Lulin BVRI Optical afterglow observation
  63. GRB051109A: further steepening in the X-ray light curve
  64. GRB051109A: XRT refined analysis
  65. GRB 051109a: BOOTES R & I-band detection of the early afterglow
  66. GRB051109B: XRT position
  67. GRB 051109B: Super-LOTIS Observations
  68. GRB 051109B Kiso optical follow-up observation
  69. GRB051105B: REM Optical observation
  70. GRB 051109B: Swift detection of a burst
  71. GRB 051109: HET Optical Spectrum and Absorption Redshift
  72. GRB 051109: PROMPT Detections
  73. GRB 051109: Rc and Ic observations
  74. GRB051109: Early Super-LOTIS Detection
  75. GRB 051109: Swift-BAT refined analysis
  76. GRB 051109a: IR Photometry and Astrometry
  77. GRB 051109a: MDM Observations
  78. GRB 051109A: ROTSE-III Decline rate for Optical Counterpart
  79. GRB051109: Swift detection of a burst
  80. GRB 051109a: IR Detections
  81. GRB 051109: ROTSE-III Detection of Possible Counterpart
  82. GRB051105B: Swift/XRT upper limit
  83. GRB051105B: Swift/UVOT upper limit
  84. GRB051103: optical observations
  85. GRB 051103, optical observations
  86. GRB051103: MASTER: OT limit and host galaxy candidates
  87. GRB051028: Swift-XRT refined analysis
  88. GRB 051105a, observation from Naini Tal and OSN
  89. GRB 051105A, 2nd epoch optical observations
  90. GRB 051105a: MDM Observations
  91. GRB 051105A: TNG optical observations
  92. GRB051105A: Swift/UVOT Observations
  93. GRB 051105A, radio observations
  94. GRB051103:_MASTER_optical_observations
  95. IPN triangulation and Konus spectrum of the bright short/hard GRB051103
  96. GRB 051105A, optical observations
  97. XRT observations of GRB 051105A
  98. GRB 051105: Swift-BAT improved refined analysis
  99. GRB 051105b: ART optical limits
  100. GRB051105B - A long GRB detected by INTEGRAL

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