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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"

36138 results found.

  1. GRB 050406: Swift XRT Position
  2. Swift-BAT detection of GRB 050406
  3. Konus-Wind observation of GRB 050401
  4. GRB050401: Radio observation at 610 MHz with GMRT
  5. GRB 050401: VLT spectroscopic redshift
  6. GRB 050401 Optical Observations
  7. GRB 050401 BAT refined analysis
  8. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  9. GRB050401: TNG R-band observation
  10. GRB 050402A: IR Analysis
  11. GRB 050402A: IR Observations
  12. GRB 050402: Early observations with Swift-UVOT
  13. Swift Trigger 113225: P60 Observations
  14. GRB 050401: Optical afterglow confirmed
  15. GRB 050401: Optical afterglow candidate
  16. Swift-BAT detection of GRB 050401
  17. GRB 050401: Prompt XRT position
  18. Retraction of three Swift GRB triggers
  19. GRB050331: No Afterglow Detected
  20. Swift-BAT detection of GRB 050331b
  21. GRB 050331: Swift UVOT Source
  22. Swift-BAT detection of GRB 050331
  23. GRB 050331: Swift XRT Position
  24. GRB050319: radio observation
  25. Konus-Wind observation of GRB 050326
  26. GRB 050326: Early observations with Swift-UVOT
  27. GRB 050326 XMM-Newton observation
  28. GRB 050326 : Planned XMM-Newton observation
  29. GRB 050326: Swift XRT Position
  30. GRB050326: optical limit 33min before GRB
  31. GRB 050326 BAT refined analysis
  32. GRB050326: delayed XRT observation
  33. Swift-BAT detection of a bright GRB 050326
  34. GRB050319, color indices
  35. GRB050319: RTT150 Optical Observations
  36. Swift-BAT trigger 112060 is not a real GRB
  37. GRB 050319: Absorption redshift from the Nordic Optical Telescope
  38. GRB 050319: ROTSE-III Refined Analysis
  39. GRB 050318: Swift-BAT refined analysis
  40. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  41. GRB050319: VLA Observations
  42. GRB 050319 R band observations
  43. GRB 050319: Swift-UVOT detection of the afterglow
  44. GRB 050315: Variability Analysis of Swift BAT Time History
  45. GRB050319: Radio Observations
  46. GRB 050319: NIR afterglow candidate
  47. GRB 050319:Near IR afterglow
  48. GRB 050318: SWIFT-UVOT refined analysis
  49. GRB 050318: Absorption redshift from Magellan
  50. GRB 050319: Optical observation
  51. GRB 050319 : Confirmation of optical afterglow decay
  52. GRB 050319: Swift-BAT refined analysis
  53. GRB050319,optical observation
  54. Swift Detection of GRB 050319
  55. GRB 050319: Detection of Possible Optical Counterpart
  56. GRB 050318: Swift/UVOT detection of afterglow emission
  57. GRB 050318: Magellan optical afterglow identification
  58. GRB050318: Swift XRT position
  59. RXTE Observations of GRB050318
  60. Swift-BAT detection of GRB 050318
  61. GRB 050315, SMARTS optical afterglow decay
  62. GRB050316: MASTER before, simultanious and follow up optical
  63. GRB 050306: ROTSE-III early limits
  64. GRB050316: MASTER optical observations
  65. GRB 050315: Swift-BAT further refined analysis
  66. GRB 050315, SMARTS optical/IR afterglow observations
  67. GRB 050315 I-band observations
  68. GRB050315: Radio afterglow
  69. GRB 050315: Absorption redshift
  70. GRB 050315: Optical afterglow identification
  71. GRB050315: Swift-BAT Refined analysis
  72. Non-detection of GRB050315 in ATCA Radio Observations
  73. GRB 050315: Swift XRT Position
  74. GRB 050219b: Gemini/GNIRS near-infrared spectroscopy
  75. GRB 050315: Early Observations with Swift/UVOT
  76. Swift-BAT detection of GRB 050315
  77. GRB 050306: Radio Observations
  78. GRB050306: 250 GHz upper limit with MAMBO at the IRAM 30m
  79. GRB050309: CONCAM pre-trigger and trigger coincident optical
  80. GRB 050306: optical afterglow
  81. GRB 050126: Redshift determination
  82. Swift-BAT trigger 107873: No Swift XRT counterpart
  83. GRB 050306: Confirmation of X-ray afterglow
  84. GRB 050309, Early optical limits from RAPTOR
  85. GRB 050306: further TAROT optical data
  86. GRB050309: Early optical limit from P60
  87. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  88. GRB 050309 : Lulin R-band observation
  89. Swift 107873: P60 Optical Observations
  90. GRB 050306: CORRECTION to date of observation
  91. GRB 050306: R-band observations
  92. GRB 050306: No Swift UVOT Optical Counterpart Detected
  93. GRB 050306: REM optical-infrared observations
  94. GRB 050306: Possible X-ray Afterglow Position from the Swift
  95. Swift trigger 107518: optical observation
  96. GRB 050306: TAROT optical observations
  97. GRB 050306,optical observation
  98. GRB 050306: Swift-BAT detection of a long burst
  99. GRB 050126: Confirmation of the NIR afterglow candidate
  100. PROMPT VRcIc Observations of GRB 050223

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