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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"

36149 results found.

  1. GRB 050408 optical candidate
  2. GRB 050408: Swift XRT Position
  3. GRB 050408: ROTSE-III Optical Limits
  4. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  5. GRB050408: MASTER optical observations
  6. GRB050401: Radio Detection
  7. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  8. GRB 050406: Magellan optical observations
  9. GRB 050406: early Swift XRT analysis results
  10. GRB 050406 BAT refined analysis
  11. GRB 050406: Early observations with Swift-UVOT
  12. GRB 050406: Swift XRT Position
  13. Swift-BAT detection of GRB 050406
  14. Konus-Wind observation of GRB 050401
  15. GRB050401: Radio observation at 610 MHz with GMRT
  16. GRB 050401: VLT spectroscopic redshift
  17. GRB 050401 Optical Observations
  18. GRB 050401 BAT refined analysis
  19. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  20. GRB050401: TNG R-band observation
  21. GRB 050402A: IR Analysis
  22. GRB 050402A: IR Observations
  23. GRB 050402: Early observations with Swift-UVOT
  24. Swift Trigger 113225: P60 Observations
  25. GRB 050401: Optical afterglow confirmed
  26. GRB 050401: Optical afterglow candidate
  27. Swift-BAT detection of GRB 050401
  28. GRB 050401: Prompt XRT position
  29. Retraction of three Swift GRB triggers
  30. GRB050331: No Afterglow Detected
  31. Swift-BAT detection of GRB 050331b
  32. GRB 050331: Swift UVOT Source
  33. Swift-BAT detection of GRB 050331
  34. GRB 050331: Swift XRT Position
  35. GRB050319: radio observation
  36. Konus-Wind observation of GRB 050326
  37. GRB 050326: Early observations with Swift-UVOT
  38. GRB 050326 XMM-Newton observation
  39. GRB 050326 : Planned XMM-Newton observation
  40. GRB 050326: Swift XRT Position
  41. GRB050326: optical limit 33min before GRB
  42. GRB 050326 BAT refined analysis
  43. GRB050326: delayed XRT observation
  44. Swift-BAT detection of a bright GRB 050326
  45. GRB050319, color indices
  46. GRB050319: RTT150 Optical Observations
  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. GRB 050319 R band observations
  54. GRB 050319: Swift-UVOT detection of the afterglow
  55. GRB 050315: Variability Analysis of Swift BAT Time History
  56. GRB050319: Radio Observations
  57. GRB 050319: NIR afterglow candidate
  58. GRB 050319:Near IR afterglow
  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. GRB050316: MASTER before, simultanious and follow up optical
  74. GRB 050306: ROTSE-III early limits
  75. GRB050316: MASTER optical observations
  76. GRB 050315: Swift-BAT further refined analysis
  77. GRB 050315, SMARTS optical/IR afterglow observations
  78. GRB 050315 I-band observations
  79. GRB050315: Radio afterglow
  80. GRB 050315: Absorption redshift
  81. GRB 050315: Optical afterglow identification
  82. GRB050315: Swift-BAT Refined analysis
  83. Non-detection of GRB050315 in ATCA Radio Observations
  84. GRB 050315: Swift XRT Position
  85. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  86. GRB 050315: Early Observations with Swift/UVOT
  87. Swift-BAT detection of GRB 050315
  88. GRB 050306: Radio Observations
  89. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  90. GRB050309: CONCAM pre-trigger and trigger coincident optical
  91. GRB 050306: optical afterglow
  92. GRB 050126: Redshift determination
  93. Swift-BAT trigger 107873: No Swift XRT counterpart
  94. GRB 050306: Confirmation of X-ray afterglow
  95. GRB 050309, Early optical limits from RAPTOR
  96. GRB 050306: further TAROT optical data
  97. GRB050309: Early optical limit from P60
  98. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  99. GRB 050309 : Lulin R-band observation
  100. Swift 107873: P60 Optical Observations

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