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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 050408: Optical afterglow confirmed
  2. GRB 050408: opitcal observation
  3. GRB 050408, optical observations
  4. GRB 050408 optical candidate
  5. GRB 050408: Swift XRT Position
  6. GRB 050408: ROTSE-III Optical Limits
  7. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  8. GRB050408: MASTER optical observations
  9. GRB050401: Radio Detection
  10. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  11. GRB 050406: Magellan optical observations
  12. GRB 050406: early Swift XRT analysis results
  13. GRB 050406 BAT refined analysis
  14. GRB 050406: Early observations with Swift-UVOT
  15. GRB 050406: Swift XRT Position
  16. Swift-BAT detection of GRB 050406
  17. Konus-Wind observation of GRB 050401
  18. GRB050401: Radio observation at 610 MHz with GMRT
  19. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  20. GRB 050401: VLT spectroscopic redshift
  21. GRB 050401 Optical Observations
  22. GRB050401: Maidanak optical observation
  23. GRB 050401 BAT refined analysis
  24. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  25. GRB050401: TNG R-band observation
  26. GRB 050402A: IR Analysis
  27. GRB050402: XDSS counterpart
  28. GRB 050402A: IR Observations
  29. GRB 050402: Early observations with Swift-UVOT
  30. Swift Trigger 113225: P60 Observations
  31. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  32. GRB 050401: Optical afterglow confirmed
  33. GRB 050401: Optical afterglow candidate
  34. Swift-BAT detection of GRB 050401
  35. GRB 050401: Prompt XRT position
  36. Retraction of three Swift GRB triggers
  37. GRB050331: No Afterglow Detected
  38. Swift-BAT detection of GRB 050331b
  39. GRB 050331: Swift UVOT Source
  40. Swift-BAT detection of GRB 050331
  41. GRB 050331: Swift XRT Position
  42. Swift Data Publicly Available Starting April 5, 2005
  43. GRB050319: radio observation
  44. Konus-Wind observation of GRB 050326
  45. GRB050326: optical limit
  46. GRB 050326: Early observations with Swift-UVOT
  47. GRB 050326 XMM-Newton observation
  48. GRB 050326 : Planned XMM-Newton observation
  49. GRB 050326: Swift XRT Position
  50. GRB050326: optical limit 33min before GRB
  51. GRB 050326 BAT refined analysis
  52. GRB050326: delayed XRT observation
  53. Swift-BAT detection of a bright GRB 050326
  54. GRB050319, optical observations
  55. GRB050319, color indices
  56. GRB050319: optical observation, March 20-22
  57. GRB050319: RTT150 Optical Observations
  58. Swift-BAT detection of a bright outburst from SGR1806-20
  59. Swift-BAT trigger 112060 is not a real GRB
  60. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  61. GRB 050319: ROTSE-III Refined Analysis
  62. GRB 050318: Swift-BAT refined analysis
  63. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  64. GRB050319: VLA Observations
  65. GRB050319: radio observation
  66. GRB 050319 R band observations
  67. GRB 050319: Swift-UVOT detection of the afterglow
  68. GRB 050315: Variability Analysis of Swift BAT Time History
  69. GRB050319: Radio Observations
  70. GRB 050319: NIR afterglow candidate
  71. GRB 050319:Near IR afterglow
  72. GRB050319: BR optical photometry
  73. GRB 050318: SWIFT-UVOT refined analysis
  74. GRB 050318: Absorption redshift from Magellan
  75. GRB 050319: Optical observation
  76. GRB 050319 : Confirmation of optical afterglow decay
  77. GRB 050319: Swift-BAT refined analysis
  78. GRB050319,optical observation
  79. Swift Detection of GRB 050319
  80. GRB 050319: Detection of Possible Optical Counterpart
  81. GRB 050318: Swift/UVOT detection of afterglow emission
  82. GRB 050318: Magellan optical afterglow identification
  83. GRB050318: Swift XRT position
  84. RXTE Observations of GRB050318
  85. Swift-BAT detection of GRB 050318
  86. GRB 050315, SMARTS optical afterglow decay
  87. GRB050223: analysis of the XMM-Newton observation
  88. GRB050316: MASTER before, simultanious and follow up optical
  89. GRB 050306: ROTSE-III early limits
  90. GRB050316: MASTER optical observations
  91. GRB 050315: Swift-BAT further refined analysis
  92. GRB 050315, SMARTS optical/IR afterglow observations
  93. GRB 050315 I-band observations
  94. GRB050315: Radio afterglow
  95. GRB 050315: Absorption redshift
  96. GRB 050315: Optical afterglow identification
  97. GRB050315: Swift-BAT Refined analysis
  98. Non-detection of GRB050315 in ATCA Radio Observations
  99. GRB 050315: Swift XRT Position
  100. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy

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