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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"

18506 results found.

  1. GRB 050410 R band Optical Observations
  2. GRB050410 : Null detection report
  3. GRB 050410, optical observations
  4. GRB050410: Radio Observations
  5. GRB 050408: Swift XRT measurement of possible jet break
  6. GRB050410: MASTER optical observations
  7. GRB 050410: Early observations with Swift-UVOT
  8. Swift-BAT detection of GRB 050410
  9. GRB 050410: Swift XRT Position
  10. GRB 050408: Properties of the Host Galaxy
  11. GRB 050408: Swift XRT analysis
  12. GRB 050408, optical observations
  13. GRB050408: REM NIR and Optical observation
  14. GRB 050408 Optical Observations
  15. GRB 050408: Optical afterglow confirmed
  16. GRB 050408, optical observations
  17. GRB 050408 optical candidate
  18. GRB 050408: Swift XRT Position
  19. Swift-UVOT Optical Counterpart Candidate to XRF 050406
  20. GRB 050406: early Swift XRT analysis results
  21. GRB 050406 BAT refined analysis
  22. GRB 050406: Early observations with Swift-UVOT
  23. GRB 050406: Swift XRT Position
  24. Swift-BAT detection of GRB 050406
  25. Konus-Wind observation of GRB 050401
  26. GRB050401: Radio observation at 610 MHz with GMRT
  27. GRB 050401: VLT spectroscopic redshift
  28. GRB 050401 Optical Observations
  29. GRB050401: Maidanak optical observation
  30. GRB 050401 BAT refined analysis
  31. Very questionable identity of Swift-BAT GRB050402 (Trig=113225)
  32. GRB 050402A: IR Observations
  33. GRB 050402: Early observations with Swift-UVOT
  34. Swift Trigger 113225: P60 Observations
  35. GRB050401: ROTSE-III Detection of Prompt Optical Counterpart
  36. GRB 050401: Optical afterglow candidate
  37. Swift-BAT detection of GRB 050401
  38. GRB 050401: Prompt XRT position
  39. Retraction of three Swift GRB triggers
  40. Swift-BAT detection of GRB 050331b
  41. GRB 050331: Swift UVOT Source
  42. Swift-BAT detection of GRB 050331
  43. GRB 050331: Swift XRT Position
  44. Swift Data Publicly Available Starting April 5, 2005
  45. Konus-Wind observation of GRB 050326
  46. GRB050326: optical limit
  47. GRB 050326: Early observations with Swift-UVOT
  48. GRB 050326 XMM-Newton observation
  49. GRB 050326 : Planned XMM-Newton observation
  50. GRB 050326: Swift XRT Position
  51. GRB050326: optical limit 33min before GRB
  52. GRB 050326 BAT refined analysis
  53. GRB050326: delayed XRT observation
  54. Swift-BAT detection of a bright GRB 050326
  55. GRB050319, optical observations
  56. GRB050319, color indices
  57. GRB050319: RTT150 Optical Observations
  58. Swift-BAT detection of a bright outburst from SGR1806-20
  59. Swift-BAT trigger 112060 is not a real GRB
  60. GRB 050319: ROTSE-III Refined Analysis
  61. GRB 050318: Swift-BAT refined analysis
  62. Refined Swift XRT positions for GRB050315, GRB050318 and GRB050319
  63. GRB 050319 R band observations
  64. GRB 050319: Swift-UVOT detection of the afterglow
  65. GRB 050315: Variability Analysis of Swift BAT Time History
  66. GRB050319: BR optical photometry
  67. GRB 050318: SWIFT-UVOT refined analysis
  68. GRB 050319: Swift-BAT refined analysis
  69. GRB050319,optical observation
  70. Swift Detection of GRB 050319
  71. GRB 050319: Detection of Possible Optical Counterpart
  72. GRB 050318: Swift/UVOT detection of afterglow emission
  73. GRB050318: Swift XRT position
  74. Swift-BAT detection of GRB 050318
  75. GRB050223: analysis of the XMM-Newton observation
  76. GRB 050306: ROTSE-III early limits
  77. GRB 050315: Swift-BAT further refined analysis
  78. GRB050315: Swift-BAT Refined analysis
  79. Non-detection of GRB050315 in ATCA Radio Observations
  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. GRB 050126: Redshift determination
  86. Swift-BAT trigger 107873: No Swift XRT counterpart
  87. GRB 050306: Confirmation of X-ray afterglow
  88. GRB 050309, Early optical limits from RAPTOR
  89. Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
  90. GRB 050309 : Lulin R-band observation
  91. Swift 107873: P60 Optical Observations
  92. GRB 050306: CORRECTION to date of observation
  93. GRB 050306: No Swift UVOT Optical Counterpart Detected
  94. GRB 050306: Possible X-ray Afterglow Position from the Swift
  95. Swift trigger 107518: optical observation
  96. GRB 050306,optical observation
  97. GRB 050306: Swift-BAT detection of a long burst
  98. GRB050215B: Late-Time Swift UVOT Observations
  99. PROMPT VRcIc Observations of GRB 050223
  100. GRB 050223: optical observations

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