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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"

26341 results found.

  1. GRB 050421: Swift-BAT refined analysis
  2. GRB050421
  3. GRB 050421: early Swift XRT analysis results
  4. GRB 050421: NIR observations
  5. GRB050421: P60 Observations
  6. GRB 050421: BOOTES-2 simultaneous optical observations
  7. GRB 050416b: Tentative Swift XRT Position
  8. GRB 050315: potential host galaxy
  9. GRB050326: analysis of the XMM-Newton observation
  10. GRB050418: Null Optical Observations
  11. GRB050416A, optical observations
  12. GRB 050418: Swift-BAT refined analysis
  13. GRB 050416: Mitsume optical observation
  14. GRB050416B: IR observations
  15. GRB050412: Radio Observations
  16. GRB 050416: Swift/UVOT detection of afterglow emission
  17. GRB050416: Refined Swift-XRT analysis
  18. GRB 050416,optical observation
  19. GRB050416: P200 NIR Observations
  20. GRB 050416: Radio observations
  21. Swift BAT/XRT Detection of GRB 050416
  22. GRB 050412: PROMPT VRcIc Observations
  23. GRB 050408: Kuiper 1.5m observations
  24. GRB 050412: early Swift XRT analysis results
  25. GRB 050412: Early Optical/Ultraviolet Observations with
  26. GRB 050408: SDSS Field Calibration
  27. GRB050412: P60 Observations
  28. GRB 050412: Swift XRT Position
  29. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  30. GRB 050412: IR and Optical observations
  31. GRB 050412: IR Observations
  32. GRB050408: Radio Observations
  33. GRB 050401: Optical limit
  34. GRB050410: P60 Observations
  35. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  36. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  37. GRB050410: Radio Observations
  38. GRB050410: MASTER optical observations
  39. GRB 050410: Early observations with Swift-UVOT
  40. Swift-BAT detection of GRB 050410
  41. GRB 050408: Inconsistency of host galaxy identification
  42. GRB 050408: Subaru Observations
  43. GRB 050408: WIDGET simultaneous optical observations
  44. GRB 050408: Properties of the Host Galaxy
  45. GRB050408: Radio Observations
  46. GRB 050408: Swift XRT analysis
  47. GRB 050408: Optical limit at 20 min after the burst
  48. GRB050408: REM NIR and Optical observation
  49. GRB 050408,optical observation
  50. GRB 050408: Mercator Optical Observations
  51. GRB 050408: Optical afterglow confirmed
  52. GRB 050408: opitcal observation
  53. GRB 050408, optical observations
  54. GRB 050408 optical candidate
  55. GRB 050408: Swift XRT Position
  56. GRB050408: MASTER optical observations
  57. GRB050401: Radio Detection
  58. GRB 050406: early Swift XRT analysis results
  59. GRB 050406 BAT refined analysis
  60. GRB 050406: Early observations with Swift-UVOT
  61. Swift-BAT detection of GRB 050406
  62. GRB050401, radio observation at 4.8 GHz and 8.64 GHz
  63. GRB 050401: VLT spectroscopic redshift
  64. GRB 050401 BAT refined analysis
  65. GRB050401: TNG R-band observation
  66. GRB 050402: Early observations with Swift-UVOT
  67. Swift Trigger 113225: P60 Observations
  68. GRB 050401: Optical afterglow confirmed
  69. GRB 050401: Prompt XRT position
  70. Retraction of three Swift GRB triggers
  71. GRB050331: No Afterglow Detected
  72. Swift-BAT detection of GRB 050331b
  73. GRB 050331: Swift UVOT Source
  74. Swift-BAT detection of GRB 050331
  75. GRB 050326: Early observations with Swift-UVOT
  76. GRB 050326 XMM-Newton observation
  77. GRB 050326: Swift XRT Position
  78. GRB 050326 BAT refined analysis
  79. GRB050326: delayed XRT observation
  80. GRB050319, color indices
  81. GRB050319: optical observation, March 20-22
  82. GRB050319: RTT150 Optical Observations
  83. Swift-BAT trigger 112060 is not a real GRB
  84. GRB 050318: Swift-BAT refined analysis
  85. GRB050319: VLA Observations
  86. GRB050319: radio observation
  87. GRB 050319: Swift-UVOT detection of the afterglow
  88. GRB 050315: Variability Analysis of Swift BAT Time History
  89. GRB050319: Radio Observations
  90. GRB 050319: NIR afterglow candidate
  91. GRB 050319:Near IR afterglow
  92. GRB 050318: SWIFT-UVOT refined analysis
  93. GRB 050319 : Confirmation of optical afterglow decay
  94. GRB 050319: Swift-BAT refined analysis
  95. GRB050319,optical observation
  96. GRB 050318: Swift/UVOT detection of afterglow emission
  97. RXTE Observations of GRB050318
  98. GRB050223: analysis of the XMM-Newton observation
  99. GRB050316: MASTER before, simultanious and follow up optical
  100. GRB 050306: ROTSE-III early limits

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