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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"

19354 results found.

  1. GRB050805a: MASTER optical candidat
  2. GRB 050824: ROTSE-III Optical Limits
  3. GRB050824: Swift-BAT detection of a burst
  4. GRB050822: Swift/UVOT upper limits
  5. GRB 050820A BAT observations of second, larger episode of emission
  6. GRB 050822: Swift-BAT refined analysis
  7. GRB 050820a - corrections to GCN 3846
  8. Swift/UVOT UV Photometry of GRB 050820B
  9. GRB 050822: ROTSE-III Prompt Optical Limits
  10. GRB 050822: Swift detection of a long burst
  11. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  12. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  13. GRB050820a BVRcIc field photometry
  14. GRB050820B XMM-Newton observation
  15. GRB 050820a: NIR Observations by WIRO
  16. GRB 050820B: Swift XRT position
  17. GRB050820B: Refined analysis of the Swift-BAT burst
  18. GRB050820B: BAT-Swift detection of a bright GRB
  19. Swift/UVOT photometry of GRB050820
  20. GRB050820: refined XRT analysis
  21. GRB 050820: Early RAPTOR detections
  22. GRB 050820 Swift-BAT refined analysis
  23. GRB050819: refined XRT analysis
  24. GRB 050820: Swift detection of a GRB
  25. GRB050820: Optical afterglow from P60
  26. GRB 050819 Swift-BAT refined analysis
  27. GRB050819: Swift XRT position
  28. GRB050819: Swift-BAT detection of a weak burst
  29. Swift-BAT trigger 150993 is not a GRB
  30. Swift Trigger 150823 is HETE J1900.1-2455
  31. GRB050817: Swift-BAT Detection of a burst
  32. GRB050815: Optical afterglow detection by Swift UVOT
  33. GRB050815: XRT refined analysis
  34. GRB050815: Refined analysis of the Swift-BAT burst
  35. GRB 050815: ROTSE-III Optical Limits
  36. GRB050815: Swift XRT afterglow localization
  37. GRB050815: Swift-BAT detection of a burst
  38. GRB050814: P60 Optical Afterglow Candidate
  39. GRB 050814: XRT refined analysis
  40. GRB050814: SWIFT/UVOT observation
  41. GRB050814: Refined analysis of the Swift-BAT burst
  42. GRB 050814: Swift XRT Afterglow Localization
  43. GRB 050814: Swift detection of a burst
  44. GRB050813, SDSS pre-burst observations
  45. GRB 050813: KAIT optical limit
  46. GRB 050813: Swift-BAT refined analysis
  47. GRB050813: SWIFT/UVOT observation
  48. GRB 050813: Swift XRT afterglow localization
  49. GRB 050813: Possible Short Swift-BAT GRB
  50. GRB050813 (Swift 150139): P60 Observations
  51. Swift-BAT trigger 150131 is not a GRB
  52. GRB050805b: CrAO optical limit
  53. GRB050805a : Null detection report
  54. Swift-BAT trigger 149118 is very likely not a GRB
  55. Retraction of Swift Trigger 149131 (GRB 050805B)
  56. GRB 050805b: OHP optical limits
  57. GRB 050805b: TAROT optical limits
  58. GRB050805b: MASTER optical observations
  59. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  60. GRB050805a: MASTER optical candidat
  61. Swift-BAT trigger 149118 is probably not a GRB
  62. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  63. GRB 050803: Swift-BAT refined analysis
  64. GRB050803: MASTER further analys
  65. GRB 050803: early Swift XRT analysis results
  66. GRB 050803: TAROT optical limits
  67. GRB050803: MASTER optical observations
  68. GRB050803: Swift-BAT detection of a very long burst
  69. GCN GRB observation 050713A
  70. GRB 050802: Swift/UVOT optical and UV detections
  71. GRB050802 radio non-detection
  72. GRB 050730: OHP optical observations
  73. GRB 050802: early Swift XRT analysis results
  74. GRB 050802: Swift/UVOT observations
  75. GRB 050802: Swift-BAT refined analysis
  76. GRB 050802: XRT position
  77. GRB 050802: Swift Gamma-ray Burst
  78. GRB050801: Swift/UVOT Optical and UV detections
  79. GCN 050801: early Swift XRT analysis results
  80. GRB 050801: Swift-BAT refined analysis
  81. GRB 050801, afterglow observations
  82. GRB 050730, corrected photometry and break?
  83. GRB 050801: ROTSE-III Early Afterglow Break
  84. GRB050801: Swift-BAT detection of a burst
  85. GRB050801: GCN XRT position is incorrect
  86. GRB 050801: ROTSE-III Detection of Possible Counterpart
  87. GRB 050730: XRT refined analysis
  88. GRB 050730: early TAROT optical observations
  89. Swift/UVOT photometry of GRB050730
  90. GRB050730: Refined BAT analysis of the Swift-BAT burst
  91. GRB 050730: Swift XRT afterglow observations
  92. GRB 050730 XMM-Newton observation
  93. GRB050730, afterglow observations
  94. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  95. GRB050730: Liverpool Telescope optical observations
  96. GRB 050730, optical candidate
  97. GRB050730: Swift-BAT detection of a weak burst
  98. GRB 050713A: Swift XRT extended light curve
  99. GRB050726: Swift UVOT observations
  100. GRB 050724: Chandra Observations of the X-ray Afterglow

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