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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"

36042 results found.

  1. GRB 050408: Swift XRT Position
  2. GRB 050408: ROTSE-III Optical Limits
  3. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  4. GRB050408: MASTER optical observations
  5. GRB050401: Radio Detection
  6. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  7. GRB 050406: Magellan optical observations
  8. GRB 050406: early Swift XRT analysis results
  9. GRB 050406 BAT refined analysis
  10. GRB 050406: Early observations with Swift-UVOT
  11. GRB 050406: Swift XRT Position
  12. Swift-BAT detection of GRB 050406
  13. Konus-Wind observation of GRB 050401
  14. GRB050401: Radio observation at 610 MHz with GMRT
  15. GRB 050401: VLT spectroscopic redshift
  16. GRB 050401 Optical Observations
  17. GRB 050401 BAT refined analysis
  18. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  19. GRB050401: TNG R-band observation
  20. GRB 050402A: IR Analysis
  21. GRB 050402A: IR Observations
  22. GRB 050402: Early observations with Swift-UVOT
  23. Swift Trigger 113225: P60 Observations
  24. GRB 050401: Optical afterglow confirmed
  25. GRB 050401: Optical afterglow candidate
  26. Swift-BAT detection of GRB 050401
  27. GRB 050401: Prompt XRT position
  28. Retraction of three Swift GRB triggers
  29. GRB050331: No Afterglow Detected
  30. Swift-BAT detection of GRB 050331b
  31. GRB 050331: Swift UVOT Source
  32. Swift-BAT detection of GRB 050331
  33. GRB 050331: Swift XRT Position
  34. GRB050319: radio observation
  35. Konus-Wind observation of GRB 050326
  36. GRB 050326: Early observations with Swift-UVOT
  37. GRB 050326 XMM-Newton observation
  38. GRB 050326 : Planned XMM-Newton observation
  39. GRB 050326: Swift XRT Position
  40. GRB050326: optical limit 33min before GRB
  41. GRB 050326 BAT refined analysis
  42. GRB050326: delayed XRT observation
  43. Swift-BAT detection of a bright GRB 050326
  44. GRB050319, color indices
  45. GRB050319: RTT150 Optical Observations
  46. Swift-BAT trigger 112060 is not a real GRB
  47. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  48. GRB 050319: ROTSE-III Refined Analysis
  49. GRB 050318: Swift-BAT refined analysis
  50. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  51. GRB050319: VLA Observations
  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. GRB 050318: SWIFT-UVOT refined analysis
  59. GRB 050318: Absorption redshift from Magellan
  60. GRB 050319: Optical observation
  61. GRB 050319 : Confirmation of optical afterglow decay
  62. GRB 050319: Swift-BAT refined analysis
  63. GRB050319,optical observation
  64. Swift Detection of GRB 050319
  65. GRB 050319: Detection of Possible Optical Counterpart
  66. GRB 050318: Swift/UVOT detection of afterglow emission
  67. GRB 050318: Magellan optical afterglow identification
  68. GRB050318: Swift XRT position
  69. RXTE Observations of GRB050318
  70. Swift-BAT detection of GRB 050318
  71. GRB 050315, SMARTS optical afterglow decay
  72. GRB050316: MASTER before, simultanious and follow up optical
  73. GRB 050306: ROTSE-III early limits
  74. GRB050316: MASTER optical observations
  75. GRB 050315: Swift-BAT further refined analysis
  76. GRB 050315, SMARTS optical/IR afterglow observations
  77. GRB 050315 I-band observations
  78. GRB050315: Radio afterglow
  79. GRB 050315: Absorption redshift
  80. GRB 050315: Optical afterglow identification
  81. GRB050315: Swift-BAT Refined analysis
  82. Non-detection of GRB050315 in ATCA Radio Observations
  83. GRB 050315: Swift XRT Position
  84. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  85. GRB 050315: Early Observations with Swift/UVOT
  86. Swift-BAT detection of GRB 050315
  87. GRB 050306: Radio Observations
  88. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  89. GRB050309: CONCAM pre-trigger and trigger coincident optical
  90. GRB 050306: optical afterglow
  91. GRB 050126: Redshift determination
  92. Swift-BAT trigger 107873: No Swift XRT counterpart
  93. GRB 050306: Confirmation of X-ray afterglow
  94. GRB 050309, Early optical limits from RAPTOR
  95. GRB 050306: further TAROT optical data
  96. GRB050309: Early optical limit from P60
  97. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  98. GRB 050309 : Lulin R-band observation
  99. Swift 107873: P60 Optical Observations
  100. GRB 050306: CORRECTION to date of observation

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