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

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