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

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