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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"

25622 results found.

  1. GRB 050416B: optical observations
  2. GRB 050416b: Swift-BAT refined analysis
  3. GRB 050416b: LCO observations
  4. GRB 050416b: LCO observations
  5. GRB050416B: IR observations
  6. GRB 050416: Swift/UVOT refined analysis
  7. Swift-BAT detection of GRB 050416b
  8. GRB 050416: Swift/UVOT detection of afterglow emission
  9. GRB050416: Refined Swift-XRT analysis
  10. GRB 050416: Swift-BAT refined analysis
  11. GRB 050416: ART observations
  12. GRB 050416,optical observation
  13. GRB 050416: KAIT observations
  14. GRB 050416: Swift XRT Position
  15. GRB 050416: Radio observations
  16. Confirmation of OT for GRB050416
  17. Swift BAT/XRT Detection of GRB 050416
  18. GRB 050412: PROMPT VRcIc Observations
  19. GRB 050412: optical limit
  20. GRB 050412: early Swift XRT analysis results
  21. GRB 050412: Swift-BAT refined analysis
  22. GRB 050412: Optical limit
  23. GRB 050412: Optical observations
  24. GRB 050412: Swift XRT Position
  25. GRB050412: optical limit before and during GRB
  26. GRB 050412: LCO optical observations
  27. GRB050412: ROTSE-III Optical Limits
  28. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  29. GRB 050412: IR Observations
  30. GRB 050401: Optical limit
  31. GRB 050408: Optical limit
  32. GRB 050410, optical observations
  33. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  34. GRB 050410 R band Optical Observations
  35. GRB 050408: Swift XRT measurement of possible jet break
  36. GRB 050410: Early observations with Swift-UVOT
  37. Swift-BAT detection of GRB 050410
  38. GRB 050410: Swift XRT Position
  39. GRB 050408: Swift XRT analysis
  40. GRB 050408,optical observation
  41. GRB 050408: Magellan astrometry and photometry
  42. GRB 050408: ROTSE-III Optical Limits
  43. GRB 050408 (=H3711): A Long X-Ray-Rich GRB Detected by HETE
  44. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  45. GRB 050406: early Swift XRT analysis results
  46. GRB 050406 BAT refined analysis
  47. GRB 050406: Early observations with Swift-UVOT
  48. GRB 050406: Swift XRT Position
  49. Swift-BAT detection of GRB 050406
  50. Konus-Wind observation of GRB 050401
  51. GRB050401: Radio observation at 610 MHz with GMRT
  52. GRB 050401 Optical Observations
  53. GRB 050401 BAT refined analysis
  54. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  55. GRB 050402: Early observations with Swift-UVOT
  56. Swift Trigger 113225: P60 Observations
  57. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  58. GRB 050401: Optical afterglow candidate
  59. Swift-BAT detection of GRB 050401
  60. GRB 050401: Prompt XRT position
  61. Retraction of three Swift GRB triggers
  62. Swift-BAT detection of GRB 050331b
  63. GRB 050331: Swift UVOT Source
  64. Swift-BAT detection of GRB 050331
  65. GRB 050331: Swift XRT Position
  66. Konus-Wind observation of GRB 050326
  67. GRB050326: optical limit
  68. GRB 050326: Early observations with Swift-UVOT
  69. GRB 050326 : Planned XMM-Newton observation
  70. GRB 050326: Swift XRT Position
  71. GRB050326: optical limit 33min before GRB
  72. GRB 050326 BAT refined analysis
  73. GRB050326: delayed XRT observation
  74. Swift-BAT detection of a bright GRB 050326
  75. GRB050319, optical observations
  76. Swift-BAT detection of a bright outburst from SGR1806-20
  77. Swift-BAT trigger 112060 is not a real GRB
  78. GRB 050319: ROTSE-III Refined Analysis
  79. GRB 050318: Swift-BAT refined analysis
  80. GRB 050319 R band observations
  81. GRB 050319: Swift-UVOT detection of the afterglow
  82. GRB 050315: Variability Analysis of Swift BAT Time History
  83. GRB 050318: SWIFT-UVOT refined analysis
  84. GRB 050319: Swift-BAT refined analysis
  85. GRB050319,optical observation
  86. Swift Detection of GRB 050319
  87. GRB 050318: Swift/UVOT detection of afterglow emission
  88. GRB 050318: Magellan optical afterglow identification
  89. GRB050318: Swift XRT position
  90. RXTE Observations of GRB050318
  91. Swift-BAT detection of GRB 050318
  92. GRB 050315: Swift-BAT further refined analysis
  93. GRB050315: Swift-BAT Refined analysis
  94. GRB 050315: Swift XRT Position
  95. GRB 050315: Early Observations with Swift/UVOT
  96. Swift-BAT detection of GRB 050315
  97. GRB050223: No XMM-Newton OM detection of afterglow emission
  98. GRB050309: CONCAM pre-trigger and trigger coincident optical
  99. Swift-BAT trigger 107873: No Swift XRT counterpart
  100. GRB 050309, Early optical limits from RAPTOR

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