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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"

28068 results found.

  1. GRB 091109B: Swift/UVOT Upper Limits
  2. GRB 091109B: VLT afterglow confirmation
  3. GRB 091109B: Swift-XRT Team refined analysis
  4. GRB 091109b: Magellan Observations
  5. GRB 091109B: Enhanced Swift-XRT position
  6. GRB 091109B: Optical limits from Watcher
  7. GRB 091109B: ROTSE-III Optical Limits
  8. GRB 091109B: Swift detection of a short burst
  9. GRB091109: Correction to GCN 10139
  10. GRB 091030: Fermi GBM detection
  11. GRB 091109: Swift-XRT refined analysis
  12. GRB 091109: BOOTES-3 observations
  13. GRB 091109: Swift/UVOT observations
  14. GRB 091109: Faulkes Telescope South observations
  15. GRB 091109: Enhanced Swift-XRT position
  16. GRB091109: REM detection of the NIR afterglow
  17. GRB 091109: Swift detection of a burst with optical afterglow
  18. GRB 091029: Observations from Stardome Observatory
  19. GRB 091104: Swift XRT Refined Analysis
  20. GRB 091104: Swift/UVOT Upper Limits
  21. GRB091026 : IRSF NIR upper limit
  22. GRB091102 : MOA optical upper limit
  23. GRB 091104: Enhanced Swift-XRT position
  24. GRB 091104: Swift detection of a burst
  25. GRB 091102: LABOCA/APEX submm observations
  26. Fermi LAT Upper Limits on GRB 091010
  27. GRB 091102 : Faulkes Telescope South Upper Limits
  28. GRB 091102A: Fermi GBM observation
  29. GRB 091102: Swift-XRT refined analysis
  30. GRB 091102: Swift/UVOT Upper Limits
  31. GRB 091102: GROND Upper Limits
  32. GRB 091102: BOOTES-3 observations
  33. GRB 091102: Swift/XRT localization
  34. GRB 091102: ROTSE-III Optical Limits
  35. GRB 091102: Swift/UVOT Finding Chart Observation
  36. GRB 091102: Swift detection of a burst
  37. GRB 091024: optical observations
  38. GRB 091031: Fermi GBM detection
  39. GRB 091024: Fermi LAT upper limits
  40. GRB 090926a, SMARTS optical/IR afterglow observations
  41. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  42. GRB 091029, SMARTS optical/IR afterglow observations
  43. GRB 091018, SMARTS optical/IR afterglow observations
  44. GRB 090920: Skynet/DSO Detection
  45. GRB091029: Swift/UVOT observations
  46. GRB 091029: Skynet/PROMPT Continued Observations of Fading
  47. GRB 091029: Swift XRT refined analysis
  48. GRB 091029: BOOTES-3 observations
  49. GRB 091029: Enhanced Swift-XRT position
  50. GRB091024 optical observations
  51. GRB 091029: Gemini-South Redshift
  52. GRB 091029: Skynet/PROMPT Observations of Peak and Fading
  53. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  54. GRB 091029: Swift detection of a burst with an optical counterpart
  55. GRB 091020: Fermi GBM observation
  56. GRB 091024: Keck/LRIS Spectroscopy
  57. GRB 091024: YNAO-GMG observations
  58. GRB 091026: GROND Upper Limits
  59. GRB 091020: Late TLS detection
  60. Radio afterglow detection from GRB 091020
  61. GRB 091026: Swift/UVOT Upper Limits
  62. GRB 091026: Swift-XRT refined analysis
  63. GRB 091026: Enhanced Swift-XRT position
  64. GRB 091026: Updated Swift-XRT position
  65. GRB 091026: Swift detection of a Gamma Ray Burst
  66. GRB 091020 : Xinglong TNT upper limit
  67. GRB091024 Swift/UVOT Upper Limits
  68. GRB 091024: TLS Upper Limit
  69. GRB 091020: Early TLS Multicolor detections, red afterglow
  70. GRB 091024: KAIT optical afterglow observations
  71. GRB 091024: Super-LOTIS early observations
  72. GRB091024: VRcIc Afterglow Observations
  73. GRB 091024: Swift-XRT team refined analysis
  74. Swift-BAT trigger 373691 is a galactic bulge transient
  75. GRB 091024: Xinglong TNT optical observation
  76. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  77. GRB 091024 Gemini-North redshift
  78. GRB 091024: GRAS004 optical observations
  79. GRB 091024: Faulkes Telescope North Afterglow Candidate
  80. GRB 091024: Swift detection of a burst
  81. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  82. GRB 091020: Additional Lick observations
  83. GRB 091020: Lick observations
  84. GRB 091020: Swift-XRT refined analysis
  85. GRB 091018: Swift XRT refined analysis
  86. GRB091020 Swift/UVOT observations
  87. GRB 091020: NOT spectroscopic redshift
  88. GRB 091020: Enhanced Swift-XRT position
  89. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  90. GRB 091020: Swift detection of a burst with an optical afterglow
  91. GRB 091018: miniTAO/ANIR Observations
  92. GRB 091018: Skynet/PROMPT Observations of Fading
  93. GRB 091018 : Faulkes Telescope South Observations
  94. GRB 091018: BOOTES-3 observations
  95. GRB 091018: VLT/X-shooter spectra
  96. GRB091018: Swift/UVOT observations
  97. GRB 091018: GROND observations
  98. GRB091018: Magellan Echellette Observations
  99. GRB 091018: Enhanced Swift-XRT position
  100. GRB 091018: ROTSE-III Detection of Optical Counterpart

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