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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. AGILE Gamma-ray detection of GRB 090401B
  2. GRB 090401B: Swift-BAT refined analysis
  3. Swift/UVOT detection of GRB090401B
  4. GRB 090401B: Swift detection of a burst
  5. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  6. GRB 090401, Swift-BAT refined analysis
  7. GRB 090323: Further TLS detections - a break?
  8. GRB 090401: Swift detection of a burst
  9. GRB 090324: Suzaku WAM observation of the prompt emission
  10. GRB 090328: Radio afterglow detection
  11. GRB 090326: Fermi GBM detection
  12. GRB 090328: BOOTES-3 optical observations
  13. GRB 090328: Fermi GBM Spectral Analysis
  14. GRB 090328B: Fermi GBM Detection
  15. GRB 090330: Fermi GBM detection
  16. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  17. GRB 090328: Gemini South Redshift
  18. GRB 090328: Swift XRT refined analysis
  19. GRB090323: Optical observations from NOT
  20. Konus-Wind observation of GRB 090328
  21. GRB 090328: IPN Triangulation
  22. GRB 090328: Swift UVOT observations
  23. GRB 090323: WSRT Radio Detection
  24. GRB 090328: Updated position/optical afterglow candidate
  25. GRB 090328: Possible Swift/XRT detection
  26. Fermi LAT and GBM detections of GRB090328
  27. GRB 090323: Radio afterglow detection
  28. GRB 090323: Additional Lick observations
  29. GRB 090323: TLS detection at 5 days, no break
  30. GRB 090327: Fermi GBM detection
  31. GRB 090323: Faulkes Telescope South Observations
  32. GRB 090320B: MASTER-Net prompt optical observations
  33. GRB 090323: RTT150 optical observations
  34. GRB 090323: Lick observations
  35. GRB 090323: Fermi GBM Spectral Analysis
  36. GRB 090323: Optical observation of xinglong TNT
  37. GRB 090323 TLS detection - still bright
  38. GRB 090323: UVOT Detection of Afterglow
  39. GRB 090323: Swift-XRT refined analysis
  40. Konus-Wind observation of GRB 090323
  41. GRB 090324: SuperAGILE Localization of a Long GRB
  42. GRB 090323 Gemini-South Redshift
  43. GRB 090323: P60 Afterglow Confirmation
  44. GRB 090323: GROND Detection of the Afterglow and Photo-z
  45. SGR J1550-5418: two Fermi GBM triggers on March 22
  46. GRB 090323: Possible XRT Counterpart
  47. IPN triangulation of GRB090323
  48. GRB 090320C: Fermi GBM Detection
  49. Fermi GBM and LAT detections of GRB 090323
  50. GRB 090320B: Fermi GBM detection.
  51. GRB 090319: Fermi GBM detection
  52. GRB 090320A: Fermi GBM detection
  53. Further 15GHz observations of GRB090313
  54. GRB 090313: WSRT Radio Detection
  55. X-shooter observations of GRB 090313
  56. A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418
  57. GRB 090315: Suzaku WAM observation of the prompt emission
  58. GRB 090313: VLT spectroscopy
  59. GRB090313: radio detection with the VLA
  60. Konus-Wind observation of GRB 090315
  61. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  62. GRB 090313, SMARTS optical/IR observations
  63. Further radio observation of GRB 090313
  64. Further Swift/UVOT observations of GRB 090313
  65. GRB 090313: detection with CARMA in 3mm band
  66. GRB090305B: MASTER-net prompt optical short burst observations
  67. Radio detection of GRB090313
  68. GRB 090313: MITSuME Okayama observation
  69. GRB 090313: Additional Gemini-S photometry
  70. GRB 090313: WSRT Radio Observations
  71. GRB 090313: Light curve steepening
  72. GRB 090313: TAROT La Silla observatory optical detection
  73. GRB 090313: Gemini-S photometry
  74. GRB 090313: Zadko Telescope observations
  75. GRB 090313 - PAIRITEL NIR detections
  76. GRB 090313: Gemini-S redshift
  77. GRB 090313 optical observations
  78. GRB 090313: Ongoing plateau phase
  79. GRB 090313: Swift-XRT refined analysis
  80. GRB 090313: Swift/UVOT upper limits
  81. GRB 090313: Faulkes Telescope North observations
  82. GRB 090313: Sustained optical brightness (correction)
  83. GRB 090306B: Confirmation of the X-ray afterglow
  84. GRB 090313: Swift-BAT refined analysis
  85. GRB 090313: Sustained optical brightness
  86. GRB 090313: SDSS object underlying the optical afterglow position
  87. GRB 090313, GROND observations
  88. GRB 090309, Swift-BAT lag analysis
  89. GRB 090313: Swift detection of a burst
  90. GRB 090313: Swift detection of a burst
  91. GRB 090313 OA candidate
  92. Swift trigger 346250 is probably not a burst
  93. GRB090310: Fermi GBM detection
  94. GRB 090205: Zadko Telescope late-time observations
  95. GRB 090309A: GROND upper limits
  96. GRB 090307A: TAROT Calern observatory optical observations
  97. GRB 090309: Swift/UVOT Upper Limits
  98. GRB090305B: Fermi GBM detection
  99. GRB 090309B: Fermi GBM detection
  100. GRB 090309: Swift-XRT refined analysis

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