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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"

27408 results found.

  1. GRB 050416: Radio observations
  2. Confirmation of OT for GRB050416
  3. Swift BAT/XRT Detection of GRB 050416
  4. GRB 050412: PROMPT VRcIc Observations
  5. GRB 050412: optical limit
  6. GRB 050412: early Swift XRT analysis results
  7. GRB 050412: Swift-BAT refined analysis
  8. GRB 050412: Optical limit
  9. GRB 050412: Optical observations
  10. GRB 050412: Swift XRT Position
  11. GRB050412: optical limit before and during GRB
  12. GRB 050412: LCO optical observations
  13. GRB050412: ROTSE-III Optical Limits
  14. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  15. GRB 050412: IR Observations
  16. GRB 050401: Optical limit
  17. GRB 050408: Optical limit
  18. GRB 050410, optical observations
  19. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  20. GRB 050410 R band Optical Observations
  21. GRB 050408: Swift XRT measurement of possible jet break
  22. GRB 050410: Early observations with Swift-UVOT
  23. Swift-BAT detection of GRB 050410
  24. GRB 050410: Swift XRT Position
  25. GRB 050408: Swift XRT analysis
  26. GRB 050408,optical observation
  27. GRB 050408: Magellan astrometry and photometry
  28. GRB 050408: ROTSE-III Optical Limits
  29. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  30. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  31. GRB 050406: early Swift XRT analysis results
  32. GRB 050406 BAT refined analysis
  33. GRB 050406: Early observations with Swift-UVOT
  34. GRB 050406: Swift XRT Position
  35. Swift-BAT detection of GRB 050406
  36. Konus-Wind observation of GRB 050401
  37. GRB050401: Radio observation at 610 MHz with GMRT
  38. GRB 050401 Optical Observations
  39. GRB 050401 BAT refined analysis
  40. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  41. GRB 050402: Early observations with Swift-UVOT
  42. Swift Trigger 113225: P60 Observations
  43. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  44. GRB 050401: Optical afterglow candidate
  45. Swift-BAT detection of GRB 050401
  46. GRB 050401: Prompt XRT position
  47. Retraction of three Swift GRB triggers
  48. Swift-BAT detection of GRB 050331b
  49. GRB 050331: Swift UVOT Source
  50. Swift-BAT detection of GRB 050331
  51. GRB 050331: Swift XRT Position
  52. Konus-Wind observation of GRB 050326
  53. GRB050326: optical limit
  54. GRB 050326: Early observations with Swift-UVOT
  55. GRB 050326 : Planned XMM-Newton observation
  56. GRB 050326: Swift XRT Position
  57. GRB050326: optical limit 33min before GRB
  58. GRB 050326 BAT refined analysis
  59. GRB050326: delayed XRT observation
  60. Swift-BAT detection of a bright GRB 050326
  61. GRB050319, optical observations
  62. Swift-BAT detection of a bright outburst from SGR1806-20
  63. Swift-BAT trigger 112060 is not a real GRB
  64. GRB 050319: ROTSE-III Refined Analysis
  65. GRB 050318: Swift-BAT refined analysis
  66. GRB 050319 R band observations
  67. GRB 050319: Swift-UVOT detection of the afterglow
  68. GRB 050315: Variability Analysis of Swift BAT Time History
  69. GRB 050318: SWIFT-UVOT refined analysis
  70. GRB 050319: Swift-BAT refined analysis
  71. GRB050319,optical observation
  72. Swift Detection of GRB 050319
  73. GRB 050318: Swift/UVOT detection of afterglow emission
  74. GRB 050318: Magellan optical afterglow identification
  75. GRB050318: Swift XRT position
  76. RXTE Observations of GRB050318
  77. Swift-BAT detection of GRB 050318
  78. GRB 050315: Swift-BAT further refined analysis
  79. GRB050315: Swift-BAT Refined analysis
  80. GRB 050315: Swift XRT Position
  81. GRB 050315: Early Observations with Swift/UVOT
  82. Swift-BAT detection of GRB 050315
  83. GRB050223: No XMM-Newton OM detection of afterglow emission
  84. GRB050309: CONCAM pre-trigger and trigger coincident optical
  85. Swift-BAT trigger 107873: No Swift XRT counterpart
  86. GRB 050309, Early optical limits from RAPTOR
  87. GRB050309: Early optical limit from P60
  88. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  89. GRB 050309 : Lulin R-band observation
  90. Swift 107873: P60 Optical Observations
  91. GRB 050306: CORRECTION to date of observation
  92. GRB 050306: No Swift UVOT Optical Counterpart Detected
  93. GRB 050306: Possible X-ray Afterglow Position from the Swift
  94. Swift trigger 107518: optical observation
  95. GRB 050306,optical observation
  96. GRB 050306: Swift-BAT detection of a long burst
  97. Ongoing activity of SGR 1806-20 after the giant flare
  98. GRB 050219b: candidate NIR afterglow
  99. Confirmed XRF nature for GRB050215b
  100. GRB 050223: optical observations

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