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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"

35946 results found.

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

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