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

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