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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 050406: Swift XRT Position
  2. Swift-BAT detection of GRB 050406
  3. Konus-Wind observation of GRB 050401
  4. GRB050401: Radio observation at 610 MHz with GMRT
  5. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  6. GRB 050401: VLT spectroscopic redshift
  7. GRB 050401 Optical Observations
  8. GRB050401: Maidanak optical observation
  9. GRB 050401 BAT refined analysis
  10. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  11. GRB050401: TNG R-band observation
  12. GRB 050402A: IR Analysis
  13. GRB050402: XDSS counterpart
  14. GRB 050402A: IR Observations
  15. GRB 050402: Early observations with Swift-UVOT
  16. Swift Trigger 113225: P60 Observations
  17. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  18. GRB 050401: Optical afterglow confirmed
  19. GRB 050401: Optical afterglow candidate
  20. Swift-BAT detection of GRB 050401
  21. GRB 050401: Prompt XRT position
  22. Retraction of three Swift GRB triggers
  23. GRB050331: No Afterglow Detected
  24. Swift-BAT detection of GRB 050331b
  25. GRB 050331: Swift UVOT Source
  26. Swift-BAT detection of GRB 050331
  27. GRB 050331: Swift XRT Position
  28. Swift Data Publicly Available Starting April 5, 2005
  29. GRB050319: radio observation
  30. Konus-Wind observation of GRB 050326
  31. GRB050326: optical limit
  32. GRB 050326: Early observations with Swift-UVOT
  33. GRB 050326 XMM-Newton observation
  34. GRB 050326 : Planned XMM-Newton observation
  35. GRB 050326: Swift XRT Position
  36. GRB050326: optical limit 33min before GRB
  37. GRB 050326 BAT refined analysis
  38. GRB050326: delayed XRT observation
  39. Swift-BAT detection of a bright GRB 050326
  40. GRB050319, optical observations
  41. GRB050319, color indices
  42. GRB050319: optical observation, March 20-22
  43. GRB050319: RTT150 Optical Observations
  44. Swift-BAT detection of a bright outburst from SGR1806-20
  45. Swift-BAT trigger 112060 is not a real GRB
  46. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  47. GRB 050319: ROTSE-III Refined Analysis
  48. GRB 050318: Swift-BAT refined analysis
  49. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  50. GRB050319: VLA Observations
  51. GRB050319: radio observation
  52. GRB 050319 R band observations
  53. GRB 050319: Swift-UVOT detection of the afterglow
  54. GRB 050315: Variability Analysis of Swift BAT Time History
  55. GRB050319: Radio Observations
  56. GRB 050319: NIR afterglow candidate
  57. GRB 050319:Near IR afterglow
  58. GRB050319: BR optical photometry
  59. GRB 050318: SWIFT-UVOT refined analysis
  60. GRB 050318: Absorption redshift from Magellan
  61. GRB 050319: Optical observation
  62. GRB 050319 : Confirmation of optical afterglow decay
  63. GRB 050319: Swift-BAT refined analysis
  64. GRB050319,optical observation
  65. Swift Detection of GRB 050319
  66. GRB 050319: Detection of Possible Optical Counterpart
  67. GRB 050318: Swift/UVOT detection of afterglow emission
  68. GRB 050318: Magellan optical afterglow identification
  69. GRB050318: Swift XRT position
  70. RXTE Observations of GRB050318
  71. Swift-BAT detection of GRB 050318
  72. GRB 050315, SMARTS optical afterglow decay
  73. GRB050223: analysis of the XMM-Newton observation
  74. GRB050316: MASTER before, simultanious and follow up optical
  75. GRB 050306: ROTSE-III early limits
  76. GRB050316: MASTER optical observations
  77. GRB 050315: Swift-BAT further refined analysis
  78. GRB 050315, SMARTS optical/IR afterglow observations
  79. GRB 050315 I-band observations
  80. GRB050315: Radio afterglow
  81. GRB 050315: Absorption redshift
  82. GRB 050315: Optical afterglow identification
  83. GRB050315: Swift-BAT Refined analysis
  84. Non-detection of GRB050315 in ATCA Radio Observations
  85. GRB 050315: Swift XRT Position
  86. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  87. GRB 050315: Early Observations with Swift/UVOT
  88. Swift-BAT detection of GRB 050315
  89. GRB050223: No XMM-Newton OM detection of afterglow emission
  90. GRB 050306: Radio Observations
  91. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  92. GRB050309: CONCAM pre-trigger and trigger coincident optical
  93. GRB 050306: optical afterglow
  94. GRB 050126: Redshift determination
  95. Swift-BAT trigger 107873: No Swift XRT counterpart
  96. GRB 050306: Confirmation of X-ray afterglow
  97. GRB 050309, Early optical limits from RAPTOR
  98. GRB 050306: further TAROT optical data
  99. GRB050309: Early optical limit from P60
  100. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts

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