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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"

19304 results found.

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

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