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

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