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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 051211B: a long GRB detected by INTEGRAL
  2. GRB 051211: Swift XRT upper limit
  3. GRB 051211:IAC80 optical observations
  4. HETE SXC localization of GRB 051211 (=H3979)
  5. GRB 051210: Optical imaging from Las Campanas
  6. GRB 051210: SALT detection limit
  7. GRB 051210: BAT further refined analysis of the short burst
  8. GRB 051210: Swift XRT refined analysis
  9. GRB 051210: FRAM early limit
  10. GRB 051210: Swift-BAT refined analysis of a short burst
  11. GRB051210: Swift UVOT Observation
  12. GRB 051210: A short GRB in a cluster?
  13. GRB 051210: Swift detection of a burst
  14. IPN observations of SGR1806-20
  15. Swift XRT positions
  16. An extraordinary long burst on December 3 from SGR1806-20
  17. IBAS Alert 2706 : not a real GRB
  18. Possible resuming of the SGR 1806-20 activity
  19. Swift UVOT Calibration Documentation
  20. GRB051117B: optical observation
  21. GRB051111: optical observaion
  22. Swift-BAT trigger 165579 is not a GRB
  23. GRB 051127: Swift-BAT detection of a possible burst
  24. GRB051117B: Swift XRT refined analysis
  25. GRB051117b: No Swift/UVOT Detection
  26. GRB051111: Rc optical observations: correction
  27. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  28. GRB 051117A: Swift/UVOT Detection of an Afterglow
  29. GRB051111: Suzaku WAM observation of the prompt emission
  30. GRB051111: Rc optical observations
  31. GRB051008: Suzaku WAM observation of the prompt emission
  32. GRB 051109B: GAO 150cm telescope Optical limit
  33. GRB 051109A : GAO 150cm telescope Rc-band detection
  34. GRB 051021 Optical Observations
  35. GRB 051117B: MARGE Optical Limits
  36. GRB 051117A and B: Radio Observations
  37. GRB 051117B: R and I observations of possible host galaxy
  38. GRB 051117b: NIR observations
  39. GRB 051117A: Refined analysis of the Swift-BAT burst
  40. GRB 051117B: Refined analysis of the Swift-BAT burst
  41. GRB051117A : XRT refined analysis
  42. GRB 051117B,optical observation
  43. GRB 051117B: Lulin R and I band observation
  44. GRB 051117B: Optical observations
  45. GRB 051117B: ROTSE-III Optical Limits
  46. GRB051117B: Swift XRT position
  47. GRB 051117B: Swift detection of a burst
  48. GRB 051117: Swift detection of a bright burst
  49. GRB051114: results of the Swift-XRT observation
  50. GRB 051028 Optical Observations
  51. GRB 051109B : Nainital upper limits
  52. GRB 051114: Radio Observations
  53. GRB 051114: Swift-BAT refined analysis
  54. GRB050925: analysis of the XMM-Newton observation
  55. GRB051109A optical observations
  56. GRB 051114: Swift-BAT detection of a short burst
  57. GRB 051111: Further spectroscopic analysis
  58. GRB 051111: Radio afterglow
  59. GRB 051113: Swift-BAT refined analysis
  60. GRB 051113: Swift-BAT detection of a burst
  61. GRB 051111: AEOS optical observations
  62. GRB051103: Radio Observations
  63. GRB 051109A Milagro GeV/TeV Observations
  64. GRB/SGR 050925: XMM-Newton ToO observation
  65. GRB051111: Swift/UVOT Observations
  66. GRB 051111A : R-band temporal decay index based on Lulin
  67. GRB051111: XRT preliminary analysis
  68. GRB 051111: Swift-BAT refined analysis
  69. GRB 051109A Optical Observations
  70. GRB 051111A : Lulin BVRI multi band afterglow observation
  71. GRB051111a: SARA Observations
  72. GRB 051111a: IR photometry
  73. GRB 051111: Keck HIRES redshift
  74. GRB 051111A: KAIT optical observations
  75. GRB 051111a: Afterglow fading in Ic
  76. GRB051111: Super-LOTIS Early Detection
  77. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  78. Faulkes Telescope R-band detection of GRB051111
  79. GRB 051103 Milagro GeV/TeV Observations
  80. GRB051111: Swift-BAT detection of a bright burst
  81. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  82. GRB 051008 Tautenburg Supernova Search
  83. GRB 051109B. Radio Observations
  84. GRB 051109A
  85. GRB051109A - radio observations
  86. GRB 051105a: GETS optical limit
  87. GRB 051109b: GETS observation
  88. GRB 051109A: KAIT optical observations
  89. Early RAPTOR measurements of GRB 051109a - the movie.
  90. Konus-Wind observation of GRB 051109A
  91. GRB 051109B: Swift-BAT refined analysis
  92. GRB 051109B: ROTSE-III Optical Limits
  93. GRB 051109A: Swift-UVOT Observations
  94. IPN triangulation and Konus spectrum of the short/soft GRB051107 (large
  95. GRB051109B: no UVOT source detected
  96. GRB051109B: XRT refined analysis
  97. GRB 051109B : Lulin Optical Observations
  98. GRB 051109A : Lulin BVRI Optical afterglow observation
  99. GRB051109A: further steepening in the X-ray light curve
  100. GRB051109A: XRT refined analysis

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