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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"

19258 results found.

  1. GRB 050824: XRT refined analysis and possible afterglow detection
  2. GRB 050824: BAT refined analysis of a soft weak burst
  3. GRB050824: MASTER:OT decay
  4. GRB050824: MASTER observation OT
  5. GRB050805a: MASTER optical candidat
  6. GRB 050824: ROTSE-III Optical Limits
  7. GRB050824: Swift-BAT detection of a burst
  8. GRB050822: Swift/UVOT upper limits
  9. GRB 050820A BAT observations of second, larger episode of emission
  10. GRB 050822: Swift-BAT refined analysis
  11. GRB 050820a - corrections to GCN 3846
  12. Swift/UVOT UV Photometry of GRB 050820B
  13. GRB 050822: ROTSE-III Prompt Optical Limits
  14. GRB 050822: Swift detection of a long burst
  15. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  16. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  17. GRB050820a BVRcIc field photometry
  18. GRB050820B XMM-Newton observation
  19. GRB 050820a: NIR Observations by WIRO
  20. GRB 050820B: Swift XRT position
  21. GRB050820B: Refined analysis of the Swift-BAT burst
  22. GRB050820B: BAT-Swift detection of a bright GRB
  23. Swift/UVOT photometry of GRB050820
  24. GRB050820: refined XRT analysis
  25. GRB 050820: Early RAPTOR detections
  26. GRB 050820 Swift-BAT refined analysis
  27. GRB050819: refined XRT analysis
  28. GRB 050820: Swift detection of a GRB
  29. GRB050820: Optical afterglow from P60
  30. GRB 050819 Swift-BAT refined analysis
  31. GRB050819: Swift XRT position
  32. GRB050819: Swift-BAT detection of a weak burst
  33. Swift-BAT trigger 150993 is not a GRB
  34. Swift Trigger 150823 is HETE J1900.1-2455
  35. GRB050817: Swift-BAT Detection of a burst
  36. GRB050815: Optical afterglow detection by Swift UVOT
  37. GRB050815: XRT refined analysis
  38. GRB050815: Refined analysis of the Swift-BAT burst
  39. GRB 050815: ROTSE-III Optical Limits
  40. GRB050815: Swift XRT afterglow localization
  41. GRB050815: Swift-BAT detection of a burst
  42. GRB050814: P60 Optical Afterglow Candidate
  43. GRB 050814: XRT refined analysis
  44. GRB050814: SWIFT/UVOT observation
  45. GRB050814: Refined analysis of the Swift-BAT burst
  46. GRB 050814: Swift XRT Afterglow Localization
  47. GRB 050814: Swift detection of a burst
  48. GRB050813, SDSS pre-burst observations
  49. GRB 050813: KAIT optical limit
  50. GRB 050813: Swift-BAT refined analysis
  51. GRB050813: SWIFT/UVOT observation
  52. GRB 050813: Swift XRT afterglow localization
  53. GRB 050813: Possible Short Swift-BAT GRB
  54. GRB050813 (Swift 150139): P60 Observations
  55. Swift-BAT trigger 150131 is not a GRB
  56. GRB050805b: CrAO optical limit
  57. GRB050805a : Null detection report
  58. Swift-BAT trigger 149118 is very likely not a GRB
  59. Retraction of Swift Trigger 149131 (GRB 050805B)
  60. GRB 050805b: OHP optical limits
  61. GRB 050805b: TAROT optical limits
  62. GRB050805b: MASTER optical observations
  63. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  64. GRB050805a: MASTER optical candidat
  65. Swift-BAT trigger 149118 is probably not a GRB
  66. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  67. GRB 050803: Swift-BAT refined analysis
  68. GRB050803: MASTER further analys
  69. GRB 050803: early Swift XRT analysis results
  70. GRB 050803: TAROT optical limits
  71. GRB050803: MASTER optical observations
  72. GRB050803: Swift-BAT detection of a very long burst
  73. GCN GRB observation 050713A
  74. GRB 050802: Swift/UVOT optical and UV detections
  75. GRB050802 radio non-detection
  76. GRB 050730: OHP optical observations
  77. GRB 050802: early Swift XRT analysis results
  78. GRB 050802: Swift/UVOT observations
  79. GRB 050802: Swift-BAT refined analysis
  80. GRB 050802: XRT position
  81. GRB 050802: Swift Gamma-ray Burst
  82. GRB050801: Swift/UVOT Optical and UV detections
  83. GCN 050801: early Swift XRT analysis results
  84. GRB 050801: Swift-BAT refined analysis
  85. GRB 050801, afterglow observations
  86. GRB 050730, corrected photometry and break?
  87. GRB 050801: ROTSE-III Early Afterglow Break
  88. GRB050801: Swift-BAT detection of a burst
  89. GRB050801: GCN XRT position is incorrect
  90. GRB 050801: ROTSE-III Detection of Possible Counterpart
  91. GRB 050730: XRT refined analysis
  92. GRB 050730: early TAROT optical observations
  93. Swift/UVOT photometry of GRB050730
  94. GRB050730: Refined BAT analysis of the Swift-BAT burst
  95. GRB 050730: Swift XRT afterglow observations
  96. GRB 050730 XMM-Newton observation
  97. GRB050730, afterglow observations
  98. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  99. GRB050730: Liverpool Telescope optical observations
  100. GRB 050730, optical candidate

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