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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"

36143 results found.

  1. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  2. GRB 050406: Magellan optical observations
  3. GRB 050406: early Swift XRT analysis results
  4. GRB 050406 BAT refined analysis
  5. GRB 050406: Early observations with Swift-UVOT
  6. GRB 050406: Swift XRT Position
  7. Swift-BAT detection of GRB 050406
  8. Konus-Wind observation of GRB 050401
  9. GRB050401: Radio observation at 610 MHz with GMRT
  10. GRB 050401: VLT spectroscopic redshift
  11. GRB 050401 Optical Observations
  12. GRB 050401 BAT refined analysis
  13. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  14. GRB050401: TNG R-band observation
  15. GRB 050402A: IR Analysis
  16. GRB 050402A: IR Observations
  17. GRB 050402: Early observations with Swift-UVOT
  18. Swift Trigger 113225: P60 Observations
  19. GRB 050401: Optical afterglow confirmed
  20. GRB 050401: Optical afterglow candidate
  21. Swift-BAT detection of GRB 050401
  22. GRB 050401: Prompt XRT position
  23. Retraction of three Swift GRB triggers
  24. GRB050331: No Afterglow Detected
  25. Swift-BAT detection of GRB 050331b
  26. GRB 050331: Swift UVOT Source
  27. Swift-BAT detection of GRB 050331
  28. GRB 050331: Swift XRT Position
  29. GRB050319: radio observation
  30. Konus-Wind observation of GRB 050326
  31. GRB 050326: Early observations with Swift-UVOT
  32. GRB 050326 XMM-Newton observation
  33. GRB 050326 : Planned XMM-Newton observation
  34. GRB 050326: Swift XRT Position
  35. GRB050326: optical limit 33min before GRB
  36. GRB 050326 BAT refined analysis
  37. GRB050326: delayed XRT observation
  38. Swift-BAT detection of a bright GRB 050326
  39. GRB050319, color indices
  40. GRB050319: RTT150 Optical Observations
  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. GRB 050319 R band observations
  48. GRB 050319: Swift-UVOT detection of the afterglow
  49. GRB 050315: Variability Analysis of Swift BAT Time History
  50. GRB050319: Radio Observations
  51. GRB 050319: NIR afterglow candidate
  52. GRB 050319:Near IR afterglow
  53. GRB 050318: SWIFT-UVOT refined analysis
  54. GRB 050318: Absorption redshift from Magellan
  55. GRB 050319: Optical observation
  56. GRB 050319 : Confirmation of optical afterglow decay
  57. GRB 050319: Swift-BAT refined analysis
  58. GRB050319,optical observation
  59. Swift Detection of GRB 050319
  60. GRB 050319: Detection of Possible Optical Counterpart
  61. GRB 050318: Swift/UVOT detection of afterglow emission
  62. GRB 050318: Magellan optical afterglow identification
  63. GRB050318: Swift XRT position
  64. RXTE Observations of GRB050318
  65. Swift-BAT detection of GRB 050318
  66. GRB 050315, SMARTS optical afterglow decay
  67. GRB050316: MASTER before, simultanious and follow up optical
  68. GRB 050306: ROTSE-III early limits
  69. GRB050316: MASTER optical observations
  70. GRB 050315: Swift-BAT further refined analysis
  71. GRB 050315, SMARTS optical/IR afterglow observations
  72. GRB 050315 I-band observations
  73. GRB050315: Radio afterglow
  74. GRB 050315: Absorption redshift
  75. GRB 050315: Optical afterglow identification
  76. GRB050315: Swift-BAT Refined analysis
  77. Non-detection of GRB050315 in ATCA Radio Observations
  78. GRB 050315: Swift XRT Position
  79. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  80. GRB 050315: Early Observations with Swift/UVOT
  81. Swift-BAT detection of GRB 050315
  82. GRB 050306: Radio Observations
  83. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  84. GRB050309: CONCAM pre-trigger and trigger coincident optical
  85. GRB 050306: optical afterglow
  86. GRB 050126: Redshift determination
  87. Swift-BAT trigger 107873: No Swift XRT counterpart
  88. GRB 050306: Confirmation of X-ray afterglow
  89. GRB 050309, Early optical limits from RAPTOR
  90. GRB 050306: further TAROT optical data
  91. GRB050309: Early optical limit from P60
  92. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  93. GRB 050309 : Lulin R-band observation
  94. Swift 107873: P60 Optical Observations
  95. GRB 050306: CORRECTION to date of observation
  96. GRB 050306: R-band observations
  97. GRB 050306: No Swift UVOT Optical Counterpart Detected
  98. GRB 050306: REM optical-infrared observations
  99. GRB 050306: Possible X-ray Afterglow Position from the Swift
  100. Swift trigger 107518: optical observation

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