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

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