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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"

18400 results found.

  1. GRB 050410: Early observations with Swift-UVOT
  2. Swift-BAT detection of GRB 050410
  3. GRB 050410: Swift XRT Position
  4. GRB 050408: Properties of the Host Galaxy
  5. GRB 050408: Swift XRT analysis
  6. GRB 050408, optical observations
  7. GRB050408: REM NIR and Optical observation
  8. GRB 050408 Optical Observations
  9. GRB 050408: Optical afterglow confirmed
  10. GRB 050408, optical observations
  11. GRB 050408 optical candidate
  12. GRB 050408: Swift XRT Position
  13. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  14. GRB 050406: early Swift XRT analysis results
  15. GRB 050406 BAT refined analysis
  16. GRB 050406: Early observations with Swift-UVOT
  17. GRB 050406: Swift XRT Position
  18. Swift-BAT detection of GRB 050406
  19. Konus-Wind observation of GRB 050401
  20. GRB050401: Radio observation at 610 MHz with GMRT
  21. GRB 050401: VLT spectroscopic redshift
  22. GRB 050401 Optical Observations
  23. GRB050401: Maidanak optical observation
  24. GRB 050401 BAT refined analysis
  25. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  26. GRB 050402A: IR Observations
  27. GRB 050402: Early observations with Swift-UVOT
  28. Swift Trigger 113225: P60 Observations
  29. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  30. GRB 050401: Optical afterglow candidate
  31. Swift-BAT detection of GRB 050401
  32. GRB 050401: Prompt XRT position
  33. Retraction of three Swift GRB triggers
  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. Swift Data Publicly Available Starting April 5, 2005
  39. Konus-Wind observation of GRB 050326
  40. GRB050326: optical limit
  41. GRB 050326: Early observations with Swift-UVOT
  42. GRB 050326 XMM-Newton observation
  43. GRB 050326 : Planned XMM-Newton observation
  44. GRB 050326: Swift XRT Position
  45. GRB050326: optical limit 33min before GRB
  46. GRB 050326 BAT refined analysis
  47. GRB050326: delayed XRT observation
  48. Swift-BAT detection of a bright GRB 050326
  49. GRB050319, optical observations
  50. GRB050319, color indices
  51. GRB050319: RTT150 Optical Observations
  52. Swift-BAT detection of a bright outburst from SGR1806-20
  53. Swift-BAT trigger 112060 is not a real GRB
  54. GRB 050319: ROTSE-III Refined Analysis
  55. GRB 050318: Swift-BAT refined analysis
  56. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  57. GRB 050319 R band observations
  58. GRB 050319: Swift-UVOT detection of the afterglow
  59. GRB 050315: Variability Analysis of Swift BAT Time History
  60. GRB050319: BR optical photometry
  61. GRB 050318: SWIFT-UVOT refined analysis
  62. GRB 050319: Swift-BAT refined analysis
  63. GRB050319,optical observation
  64. Swift Detection of GRB 050319
  65. GRB 050319: Detection of Possible Optical Counterpart
  66. GRB 050318: Swift/UVOT detection of afterglow emission
  67. GRB050318: Swift XRT position
  68. Swift-BAT detection of GRB 050318
  69. GRB050223: analysis of the XMM-Newton observation
  70. GRB 050306: ROTSE-III early limits
  71. GRB 050315: Swift-BAT further refined analysis
  72. GRB050315: Swift-BAT Refined analysis
  73. Non-detection of GRB050315 in ATCA Radio Observations
  74. GRB 050315: Swift XRT Position
  75. GRB 050315: Early Observations with Swift/UVOT
  76. Swift-BAT detection of GRB 050315
  77. GRB050223: No XMM-Newton OM detection of afterglow emission
  78. GRB050309: CONCAM pre-trigger and trigger coincident optical
  79. GRB 050126: Redshift determination
  80. Swift-BAT trigger 107873: No Swift XRT counterpart
  81. GRB 050306: Confirmation of X-ray afterglow
  82. GRB 050309, Early optical limits from RAPTOR
  83. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  84. GRB 050309 : Lulin R-band observation
  85. Swift 107873: P60 Optical Observations
  86. GRB 050306: CORRECTION to date of observation
  87. GRB 050306: No Swift UVOT Optical Counterpart Detected
  88. GRB 050306: Possible X-ray Afterglow Position from the Swift
  89. Swift trigger 107518: optical observation
  90. GRB 050306,optical observation
  91. GRB 050306: Swift-BAT detection of a long burst
  92. GRB050215B: Late-Time Swift UVOT Observations
  93. PROMPT VRcIc Observations of GRB 050223
  94. GRB 050223: optical observations
  95. GRB050223 XMM-Newton observation
  96. INTEGRAL detection of GRB 050223
  97. GRB050223: No Swift UVOT Detection of Afterglow Emission
  98. GRB050223: ROTSE-III Optical Observations
  99. GRB 050223 Swift/BAT detection of a burst
  100. GRB 050223: Swift XRT Position

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