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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"

36034 results found.

  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. GRB 050401: VLT spectroscopic redshift
  8. GRB 050401 Optical Observations
  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. GRB 050402A: IR Observations
  14. GRB 050402: Early observations with Swift-UVOT
  15. Swift Trigger 113225: P60 Observations
  16. GRB 050401: Optical afterglow confirmed
  17. GRB 050401: Optical afterglow candidate
  18. Swift-BAT detection of GRB 050401
  19. GRB 050401: Prompt XRT position
  20. Retraction of three Swift GRB triggers
  21. GRB050331: No Afterglow Detected
  22. Swift-BAT detection of GRB 050331b
  23. GRB 050331: Swift UVOT Source
  24. Swift-BAT detection of GRB 050331
  25. GRB 050331: Swift XRT Position
  26. GRB050319: radio observation
  27. Konus-Wind observation of GRB 050326
  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, color indices
  37. GRB050319: RTT150 Optical Observations
  38. Swift-BAT trigger 112060 is not a real GRB
  39. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  40. GRB 050319: ROTSE-III Refined Analysis
  41. GRB 050318: Swift-BAT refined analysis
  42. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  43. GRB050319: VLA Observations
  44. GRB 050319 R band observations
  45. GRB 050319: Swift-UVOT detection of the afterglow
  46. GRB 050315: Variability Analysis of Swift BAT Time History
  47. GRB050319: Radio Observations
  48. GRB 050319: NIR afterglow candidate
  49. GRB 050319:Near IR afterglow
  50. GRB 050318: SWIFT-UVOT refined analysis
  51. GRB 050318: Absorption redshift from Magellan
  52. GRB 050319: Optical observation
  53. GRB 050319 : Confirmation of optical afterglow decay
  54. GRB 050319: Swift-BAT refined analysis
  55. GRB050319,optical observation
  56. Swift Detection of GRB 050319
  57. GRB 050319: Detection of Possible Optical Counterpart
  58. GRB 050318: Swift/UVOT detection of afterglow emission
  59. GRB 050318: Magellan optical afterglow identification
  60. GRB050318: Swift XRT position
  61. RXTE Observations of GRB050318
  62. Swift-BAT detection of GRB 050318
  63. GRB 050315, SMARTS optical afterglow decay
  64. GRB050316: MASTER before, simultanious and follow up optical
  65. GRB 050306: ROTSE-III early limits
  66. GRB050316: MASTER optical observations
  67. GRB 050315: Swift-BAT further refined analysis
  68. GRB 050315, SMARTS optical/IR afterglow observations
  69. GRB 050315 I-band observations
  70. GRB050315: Radio afterglow
  71. GRB 050315: Absorption redshift
  72. GRB 050315: Optical afterglow identification
  73. GRB050315: Swift-BAT Refined analysis
  74. Non-detection of GRB050315 in ATCA Radio Observations
  75. GRB 050315: Swift XRT Position
  76. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  77. GRB 050315: Early Observations with Swift/UVOT
  78. Swift-BAT detection of GRB 050315
  79. GRB 050306: Radio Observations
  80. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  81. GRB050309: CONCAM pre-trigger and trigger coincident optical
  82. GRB 050306: optical afterglow
  83. GRB 050126: Redshift determination
  84. Swift-BAT trigger 107873: No Swift XRT counterpart
  85. GRB 050306: Confirmation of X-ray afterglow
  86. GRB 050309, Early optical limits from RAPTOR
  87. GRB 050306: further TAROT optical data
  88. GRB050309: Early optical limit from P60
  89. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  90. GRB 050309 : Lulin R-band observation
  91. Swift 107873: P60 Optical Observations
  92. GRB 050306: CORRECTION to date of observation
  93. GRB 050306: R-band observations
  94. GRB 050306: No Swift UVOT Optical Counterpart Detected
  95. GRB 050306: REM optical-infrared observations
  96. GRB 050306: Possible X-ray Afterglow Position from the Swift
  97. Swift trigger 107518: optical observation
  98. GRB 050306: TAROT optical observations
  99. GRB 050306,optical observation
  100. GRB 050306: Swift-BAT detection of a long burst

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