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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"

28042 results found.

  1. GRB 100915B: Fermi GBM observation
  2. GRB 100915A: Correction to Swift-BAT refined analysis
  3. GRB 100915A: Swift/UVOT Upper Limits
  4. GRB 100915A: Swift-BAT refined analysis
  5. GRB 100915A: Swift-XRT refined analysis
  6. GRB 100915A: Enhanced Swift-XRT position
  7. GRB 100915B: a long GRB detected by INTEGRAL
  8. GRB 100915A: Swift detection of a likely burst
  9. GRB 100910A: Fermi GBM detection
  10. Swift BAT Trigger 433953 probably not a GRB
  11. GRB100909A: MITSuME Ishigakijima Optical upper limits
  12. GRB 100909A: Swift/UVOT observations
  13. GRB 100901A: errata of GRB name in GCN 11270
  14. GRB 100909A: Swift-XRT refined analysis
  15. GRB 100906A: optical observations at Mt.Terskol
  16. GRB 100901A: optical observation in Maidanak, break confirmation
  17. GRB 100909A: Faulkes Telescope North afterglow candidate
  18. GRB 100902A : Confirmation of afterglow and re-brightening with CFHT r’-band imaging
  19. GRB 100909A: Swift target of opportunity observation
  20. GRB100906A: detection at 15GHz
  21. GRB100901A: IAO optical upper limits at 4 days after the burst
  22. GRB100906A: R band observations
  23. GRB100906A: non-detection at 15GHz
  24. GRB100906A: Optical observations at IAO
  25. GRB 100906A: Fermi GBM observation
  26. GRB 100906A: Swift-XRT refined analysis
  27. GRB 100906A: Enhanced Swift-XRT position
  28. GRB 100906A: Swift/UVOT Observations
  29. GRB100906A: MITSuME Okayama Optical Observation
  30. GRB 100905A: Swift/UVOT Upper Limits
  31. GRB 100901A: TLS observations, SDSS calibration, decay slope
  32. GRB 100906A: MASTER preliminary prompt+afterglow lc
  33. GRB 100906A: Swift-BAT refined analysis
  34. GRB 100906A: Swift detection of a burst with an optical afterglow
  35. GRB 100829A: MASTER optical observations
  36. GRB100905A: Optical upper limits at IAO
  37. GRB100905A: MITSuME Okayama optical upper limits
  38. GRB 100905A: Swift-XRT refined analysis.
  39. GRB100905A: 1.5m OSN upper limit
  40. GRB 100905A: Enhanced Swift-XRT position
  41. GRB 100905A: Swift-BAT refined analysis
  42. GRB 100905A: Faulkes Telescope North observations
  43. GRB 100905A: Swift detection of a burst
  44. GRB10901A: Murikabushi telescope observation at 3 days after the burst
  45. GRB 100901A: Submm observations from SMA
  46. GRB 100904A: Swift-BAT refined analysis
  47. GRB100902A: Optical upper limits at IAO
  48. GRB10901A: Optical observations at IAO
  49. GRB 100902A: Swift-BAT refined analysis
  50. IPN Triangulation of the very bright GRB 100829A
  51. GRB 100902A: Swift XRT refined analysis
  52. GRB 100902A: Swift/UVOT Upper Limits
  53. GRB 100902A: optical observation at Mt.Terskol
  54. GRB 100901A: optical observation at Mt.Terskol
  55. GRB100901A: MITSuME Okayama Optical Observation at 1 day after the burst
  56. GRB 100902A: Enhanced Swift-XRT position
  57. GRB 100901A: TLS Observations: Break?
  58. GRB 100901A: ISON-NM optical observations
  59. GRB 100902A: Faulkes Telescope South observations
  60. GRB 100902A: Swift detection of a burst
  61. GRB 100901A: Vega telescope optical afterglow observation
  62. Swift/UVOT Observations of GRB100901A
  63. GRB 100901A: SARA-N observations
  64. GRB 100901A: THO optical observations
  65. GRB100901A: MITSuME Okayama Optical Observation
  66. GRB 100901A: Swift-XRT Team refined analysis
  67. GRB 100901A - NOT optical observation
  68. GRB 100901A: Swift-BAT refined analysis
  69. GRB 100901A: Enhanced Swift-XRT position
  70. GRB 100901A: Swift detection of a burst with an optical afterglow
  71. GRB 100829.9: MASTER Optical Limits
  72. GRB 100823A: optical upper limit
  73. GRB 100814A: Maidanak optical observations
  74. GRB 100823A: optical observations
  75. GRB 100725B: Mondy optical upper limit
  76. GRB 100725B: Maidanak optical upper limit
  77. GRB100807A: R band observations
  78. GRB 100823A: Swift XRT refined analysis
  79. GRB 100823A - second epoch WHT observations
  80. GRB 100823A: TNG NIR observations
  81. GRB 100823A: Swift/UVOT Upper Limits
  82. GRB 100823A: WHT observations
  83. GRB 100823A: Swift-BAT refined analysis
  84. GRB 100823A: Enhanced Swift-XRT position
  85. GRB 100823A: Swift detection of a burst
  86. GRB 100814A: Suzaku WAM observation of the prompt emission
  87. GRB 100814B: Fermi GBM detection
  88. GRB 100814A: optical observations
  89. GRB100816A: MITSuME optical upper limits
  90. GRB 100814A: NOT optical observations
  91. GRB 100816A: NOT optical observations
  92. GRB 100814A : Lulin optical observation
  93. GRB 100816A : Lulin r'-band observation
  94. GRB 100816A: Swift UVOT Observations
  95. GRB100816A Swift-XRT refined analysis
  96. GRB 100816A: Swift-BAT spectral lag results
  97. GRB 100816A: 1.23m CAHA optical observations
  98. GRB 100816A, Swift-BAT refined analysis
  99. GRB 100816A: Enhanced Swift-XRT position
  100. GRB 100816A: Gemini-N imaging

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Download all Circulars as a .tar.gz archive (updated once a day):
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