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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: RTT150 optical observations
  2. GRB051211b: P60 Observations
  3. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  4. GRB 051211B: Swift XRT Observations
  5. GRB 051210: Swift/UVOT upper limits
  6. GRB 051210: Magellan Imaging
  7. GRB 051211: TAROT optical limits
  8. GRB 051211B: a possible optical detection by TAROT
  9. GRB 051211B: a long GRB detected by INTEGRAL
  10. GRB 051211: Swift XRT upper limit
  11. GRB 051211:IAC80 optical observations
  12. HETE SXC localization of GRB 051211 (=H3979)
  13. GRB 051210: Optical imaging from Las Campanas
  14. GRB 051210: SALT detection limit
  15. GRB 051210: BAT further refined analysis of the short burst
  16. GRB 051210: Swift XRT refined analysis
  17. GRB 051210: FRAM early limit
  18. GRB 051210: Swift-BAT refined analysis of a short burst
  19. GRB051210: Swift UVOT Observation
  20. GRB 051210: A short GRB in a cluster?
  21. GRB 051210: Swift detection of a burst
  22. IPN observations of SGR1806-20
  23. Swift XRT positions
  24. An extraordinary long burst on December 3 from SGR1806-20
  25. IBAS Alert 2706 : not a real GRB
  26. Possible resuming of the SGR 1806-20 activity
  27. Swift UVOT Calibration Documentation
  28. GRB051117B: optical observation
  29. GRB051111: optical observaion
  30. Swift-BAT trigger 165579 is not a GRB
  31. GRB 051127: Swift-BAT detection of a possible burst
  32. GRB051117B: Swift XRT refined analysis
  33. GRB051117b: No Swift/UVOT Detection
  34. GRB051111: Rc optical observations: correction
  35. GRB 051117A: Swift/UVOT Detection of an Afterglow: Correction
  36. GRB 051117A: Swift/UVOT Detection of an Afterglow
  37. GRB051111: Suzaku WAM observation of the prompt emission
  38. GRB051111: Rc optical observations
  39. GRB051008: Suzaku WAM observation of the prompt emission
  40. GRB 051109B: GAO 150cm telescope Optical limit
  41. GRB 051109A : GAO 150cm telescope Rc-band detection
  42. GRB 051021 Optical Observations
  43. GRB 051117B: MARGE Optical Limits
  44. GRB 051117A and B: Radio Observations
  45. GRB 051117B: R and I observations of possible host galaxy
  46. GRB 051117b: NIR observations
  47. GRB 051117A: Refined analysis of the Swift-BAT burst
  48. GRB 051117B: Refined analysis of the Swift-BAT burst
  49. GRB051117A : XRT refined analysis
  50. GRB 051117B,optical observation
  51. GRB 051117B: Lulin R and I band observation
  52. GRB 051117B: Optical observations
  53. GRB 051117B: ROTSE-III Optical Limits
  54. GRB051117B: Swift XRT position
  55. GRB 051117B: Swift detection of a burst
  56. GRB 051117: Swift detection of a bright burst
  57. GRB051114: results of the Swift-XRT observation
  58. GRB 051028 Optical Observations
  59. GRB 051109B : Nainital upper limits
  60. GRB 051114: Radio Observations
  61. GRB 051114: Swift-BAT refined analysis
  62. GRB050925: analysis of the XMM-Newton observation
  63. GRB051109A optical observations
  64. GRB 051114: Swift-BAT detection of a short burst
  65. GRB 051111: Further spectroscopic analysis
  66. GRB 051111: Radio afterglow
  67. GRB 051113: Swift-BAT refined analysis
  68. GRB 051113: Swift-BAT detection of a burst
  69. GRB 051111: AEOS optical observations
  70. GRB051103: Radio Observations
  71. GRB 051109A Milagro GeV/TeV Observations
  72. GRB/SGR 050925: XMM-Newton ToO observation
  73. GRB051111: Swift/UVOT Observations
  74. GRB 051111A : R-band temporal decay index based on Lulin
  75. GRB051111: XRT preliminary analysis
  76. GRB 051111: Swift-BAT refined analysis
  77. GRB 051109A Optical Observations
  78. GRB 051111A : Lulin BVRI multi band afterglow observation
  79. GRB051111a: SARA Observations
  80. GRB 051111a: IR photometry
  81. GRB 051111: Keck HIRES redshift
  82. GRB 051111A: KAIT optical observations
  83. GRB 051111a: Afterglow fading in Ic
  84. GRB051111: Super-LOTIS Early Detection
  85. GRB 051111: ROTSE-III Analysis of Prompt Counterpart
  86. Faulkes Telescope R-band detection of GRB051111
  87. GRB 051103 Milagro GeV/TeV Observations
  88. GRB051111: Swift-BAT detection of a bright burst
  89. GRB 051111A: ROTSE-III Detection of Possible Counterpart
  90. GRB 051008 Tautenburg Supernova Search
  91. GRB 051109B. Radio Observations
  92. GRB 051109A
  93. GRB051109A - radio observations
  94. GRB 051105a: GETS optical limit
  95. GRB 051109b: GETS observation
  96. GRB 051109A: KAIT optical observations
  97. Early RAPTOR measurements of GRB 051109a - the movie.
  98. Konus-Wind observation of GRB 051109A
  99. GRB 051109B: Swift-BAT refined analysis
  100. GRB 051109B: ROTSE-III Optical Limits

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