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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"

37746 results found.

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

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