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

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