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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. Konus-Wind observations of GRB 090831A
  2. Swift Trigger 361477, called GRB090831B, is probably not real.
  3. GRB090831C: Swift/UVOT upper limits
  4. GRB 090831B: MITSuME optical upper limits
  5. GRB 090831C: Swift XRT Refined Analysis
  6. GRB 090829B: Fermi GBM Detection
  7. GRB 090831C: Enhanced Swift-XRT position
  8. GRB 090831C: Swift detection of a burst
  9. GRB 090831B, RIMOTS optical upper limits
  10. GRB 090831: MAXI GSC detection
  11. GRB 090831B: Swift detection of a possible burst
  12. GRB 090831: Fermi GBM detection
  13. GRB090829: Fermi GBM Detection
  14. Konus-Wind observations of GRB 090827
  15. GRB 090827: Swift XRT and UVOT observations
  16. GRB 090827 Burst discovered in BAT ground analysis
  17. GRB 090826: Fermi GBM detection
  18. GRB 090828: Fermi GBM detection
  19. Fermi Gamma-ray Burst Monitor trigger 273123112 is not a GRB
  20. GRB 090817 - TLS Observations
  21. GRB090817: Keck/LRIS Spectroscopy
  22. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  23. GRB 090823: Confirmation of Swift-BAT position by BAT Slew Survey
  24. GRB 090823 Correction to BAT position
  25. GRB 090817: No host galaxy, no supernova
  26. Konus-Wind observations of GRB 090823
  27. GRB 090823 Long burst with IPN triangulation and BAT position
  28. GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
  29. GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
  30. GRB 090820B: Fermi GBM detection
  31. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  32. GRB 090820: MASTER-Net optical polarization observations
  33. GRB 090820: Fermi GBM Detection of a bright burst.
  34. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  35. GRB 090817: Liverpool Telescope Observations
  36. GRB 090817: optical upper limit
  37. GRB 090817: Confirmation of the X-ray afterglow
  38. GRB 090815C: Swift refined analysis
  39. GRB 090817: Fermi GBM observation
  40. GRB 090817: Swift/UVOT Upper Limits
  41. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  42. GRB 090813: I-band observations from 1.5m OSN telescope
  43. GRB 090817: Swift-XRT observations
  44. GRB 090814A: optical observations
  45. GRB 090813: Suzaku WAM observation of the prompt emission
  46. GRB 090812: Suzaku WAM observation of the prompt emission
  47. GRB 090817: a long GRB localized by INTEGRAL
  48. VLA radio non-detection of GRB 090812
  49. GRB 090815B: Fermi GBM detection
  50. GRB 090815: Fermi GBM detection
  51. GRB 090813: CrAO optical obsevations
  52. GRB 090814B: Confirmation of the X-ray afterglow
  53. GRB090814A: NOT optical follow-ups
  54. GRB 090814B: I-band observations from 1.23m CAHA telescope
  55. GRB 090814B: Swift/UVOT Upper Limits
  56. GRB 090814B: Liverpool Telescope Observations
  57. Fermi Gamma-ray Burst Monitor trigger 271934815 is not a GRB
  58. GRB 090814C: Fermi GBM detection
  59. GRB 090814B: Swift-XRT detection of a possible afterglow.
  60. GRB 090814A: Swift/UVOT Observations
  61. GRB 090814A: Swift-XRT Team Refined Analysis
  62. GRB 090814A, RIMOTS optical upper limits
  63. GRB 090814A: Swift-BAT refined analysis
  64. GRB 090813: correction to GCN 9787
  65. GRB090814A: VLT spectroscopy
  66. GRB 090814: Enhanced Swift-XRT position
  67. GRB 090814B: a long GRB localized by INTEGRAL
  68. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  69. GRB 090814: Swift detection of a burst
  70. GRB 090813: Fermi GBM observation
  71. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  72. GRB 090813: Swift-XRT refined analysis
  73. Fermi Gamma-ray Burst Monitor trigger 271833016 is not a GRB
  74. GRB 090813, Swift-BAT refined analysis
  75. Konus-Wind observations of GRB090813
  76. GRB090813: Swift/UVOT upper limits
  77. GRB 090813: Enhanced Swift-XRT position
  78. GRB 090813: Liverpool Telescope afterglow confirmation
  79. GRB 090813: P60 Optical Afterglow Confirmation
  80. GRB 090813: optical candidate from 1.23m CAHA telescope
  81. GRB 090813: Swift detection of a burst
  82. GRB 090812: WIRO NIR upper limit
  83. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  84. GRB 090812: RAPTOR detections during the burst
  85. GRB 090812: Swift XRT refined analysis
  86. GRB 090812, RIMOTS optical upper limits
  87. GRB 090812 Swift-BAT Refined Analysis
  88. GRB090812: Swift/UVOT observations
  89. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  90. GRB 090812: Enhanced Swift-XRT position
  91. GRB 090812 VLT redshift
  92. GRB 090812: Liverpool Telescope afterglow confirmation
  93. GRB 090812: P60 Confirmation of Optical Afterglow
  94. GRB 090812: Swift detection of a burst with an optical counterpart
  95. GRB 090807B: Fermi GBM detection
  96. GRB 090809: Further NOT optical observations
  97. VLA radio upper limit on GRB 090809
  98. GRB 090621B: MAGIC telescope GeV observation
  99. GRB 090621A: MAGIC telescope GeV observation
  100. GRB 090809: WHT observations

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