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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"
  1. GRB 090904B: Enhanced Swift-XRT position
  2. GRB090904A: Correction to enhanced XRT position
  3. GRB 090904A: Enhanced Swift-XRT position
  4. GRB 090904A: NOT observations
  5. GRB 090902B: WSRT Radio Observation
  6. GRB090904B: REM observations
  7. GRB 090904B: Swift detection of a burst
  8. GRB 090904A: ROTSE-III Optical Limits
  9. GRB 090904: Swift detection of a burst
  10. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  11. GRB 090902B: Swift/UVOT refined analysis
  12. GRB090902B: Swift XRT refined analysis
  13. GRB 090902B: Faulkes Telescope North observations
  14. GRB 090902B: GROND NIR Afterglow Observations
  15. GRB 090902B: Gemini-N absorption redshift
  16. GRB 090902B: Fermi LAT and GBM refined analysis.
  17. GRB 090902B: Enhanced Swift-XRT position
  18. GRB 090902B: Optical afterglow candidate
  19. GRB090902B: Swift/UVOT observations
  20. GRB 090902B: Swift/XRT Afterglow Candidate
  21. GRB 090902B: Fermi LAT detection
  22. GRB 090902B: Fermi GBM detection of a bright burst
  23. GRB 090902: Fermi GBM detection
  24. GRB 090831A: IPN Triangulation
  25. GRB 090831C BAT refined analysis
  26. GRB 090831C: GROND upper limits
  27. Konus-Wind observations of GRB 090831A
  28. Swift Trigger 361477, called GRB090831B, is probably not real.
  29. GRB090831C: Swift/UVOT upper limits
  30. GRB 090831B: MITSuME optical upper limits
  31. GRB 090831C: Swift XRT Refined Analysis
  32. GRB 090829B: Fermi GBM Detection
  33. GRB 090831C: Enhanced Swift-XRT position
  34. GRB 090831C: Swift detection of a burst
  35. GRB 090831B, RIMOTS optical upper limits
  36. GRB 090831: MAXI GSC detection
  37. GRB 090831B: Swift detection of a possible burst
  38. GRB 090831: Fermi GBM detection
  39. GRB090829: Fermi GBM Detection
  40. Konus-Wind observations of GRB 090827
  41. GRB 090827: Swift XRT and UVOT observations
  42. GRB 090827 Burst discovered in BAT ground analysis
  43. GRB 090826: Fermi GBM detection
  44. GRB 090828: Fermi GBM detection
  45. Fermi Gamma-ray Burst Monitor trigger 273123112 is not a GRB
  46. GRB 090817 - TLS Observations
  47. GRB090817: Keck/LRIS Spectroscopy
  48. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  49. GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey
  50. GRB 090823 Correction to BAT position
  51. GRB 090817: No host galaxy, no supernova
  52. Konus-Wind observations of GRB 090823
  53. GRB 090823 Long burst with IPN triangulation and BAT position
  54. GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
  55. GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
  56. GRB 090820B: Fermi GBM detection
  57. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  58. GRB 090820: MASTER-Net optical polarization observations
  59. GRB 090820: Fermi GBM Detection of a bright burst.
  60. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  61. GRB 090817: Liverpool Telescope Observations
  62. GRB 090817: optical upper limit
  63. GRB 090817: Confirmation of the X-ray afterglow
  64. GRB 090815C: Swift refined analysis
  65. GRB 090817: Fermi GBM observation
  66. GRB 090817: Swift/UVOT Upper Limits
  67. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  68. GRB 090813: I-band observations from 1.5m OSN telescope
  69. GRB 090817: Swift-XRT observations
  70. GRB 090814A: optical observations
  71. GRB 090813: Suzaku WAM observation of the prompt emission
  72. GRB 090812: Suzaku WAM observation of the prompt emission
  73. GRB 090817: a long GRB localized by INTEGRAL
  74. VLA radio non-detection of GRB 090812
  75. GRB 090815B: Fermi GBM detection
  76. GRB 090815: Fermi GBM detection
  77. GRB 090813: CrAO optical obsevations
  78. GRB 090814B: Confirmation of the X-ray afterglow
  79. GRB090814A: NOT optical follow-ups
  80. GRB 090814B: I-band observations from 1.23m CAHA telescope
  81. GRB 090814B: Swift/UVOT Upper Limits
  82. GRB 090814B: Liverpool Telescope Observations
  83. Fermi Gamma-ray Burst Monitor trigger 271934815 is not a GRB
  84. GRB 090814C: Fermi GBM detection
  85. GRB 090814B: Swift-XRT detection of a possible afterglow.
  86. GRB 090814A: Swift/UVOT Observations
  87. GRB 090814A: Swift-XRT Team Refined Analysis
  88. GRB 090814A, RIMOTS optical upper limits
  89. GRB 090814A: Swift-BAT refined analysis
  90. GRB 090813: correction to GCN 9787
  91. GRB090814A: VLT spectroscopy
  92. GRB 090814: Enhanced Swift-XRT position
  93. GRB 090814B: a long GRB localized by INTEGRAL
  94. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  95. GRB 090814: Swift detection of a burst
  96. GRB 090813: Fermi GBM observation
  97. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  98. GRB 090813: Swift-XRT refined analysis
  99. Fermi Gamma-ray Burst Monitor trigger 271833016 is not a GRB
  100. GRB 090813, Swift-BAT refined analysis

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