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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"

35948 results found.

  1. GRB 090401B: NOT optical observations
  2. GRB 090328: Fermi-LAT refined analysis
  3. GRB 090401B: AGILE refined analysis
  4. GRB 090401B: Swift XRT Refined Analysis
  5. GRB 090331: Fermi GBM detection
  6. Konus-Wind observation of GRB 090401A
  7. GRB 090401B: Enhanced Swift-XRT position
  8. AGILE Gamma-ray detection of GRB 090401B
  9. GRB 090401B: Swift-BAT refined analysis
  10. GRB 090401B: Swift detection of a burst
  11. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  12. GRB 090401, Swift-BAT refined analysis
  13. GRB 090323: Further TLS detections - a break?
  14. GRB 090401: Swift detection of a burst
  15. GRB 090324: Suzaku WAM observation of the prompt emission
  16. GRB 090328: Radio afterglow detection
  17. GRB 090326: Fermi GBM detection
  18. GRB 090328: BOOTES-3 optical observations
  19. GRB 090328: Fermi GBM Spectral Analysis
  20. GRB 090328B: Fermi GBM Detection
  21. GRB 090330: Fermi GBM detection
  22. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  23. GRB 090328: Gemini South Redshift
  24. GRB 090328: Swift XRT refined analysis
  25. GRB090323: Optical observations from NOT
  26. Konus-Wind observation of GRB 090328
  27. GRB 090328: IPN Triangulation
  28. GRB 090328: Swift UVOT observations
  29. GRB 090323: WSRT Radio Detection
  30. GRB 090328: Updated position/optical afterglow candidate
  31. GRB 090328: Possible Swift/XRT detection
  32. Fermi LAT and GBM detections of GRB090328
  33. GRB 090323: Radio afterglow detection
  34. GRB 090323: Additional Lick observations
  35. GRB 090323: TLS detection at 5 days, no break
  36. GRB 090327: Fermi GBM detection
  37. GRB 090323: Faulkes Telescope South Observations
  38. GRB 090320B: MASTER-Net prompt optical observations
  39. GRB 090323: RTT150 optical observations
  40. GRB 090323: Lick observations
  41. GRB 090323: Fermi GBM Spectral Analysis
  42. GRB 090323: Optical observation of xinglong TNT
  43. GRB 090323 TLS detection - still bright
  44. GRB 090323: UVOT Detection of Afterglow
  45. GRB 090323: Swift-XRT refined analysis
  46. Konus-Wind observation of GRB 090323
  47. GRB 090324: SuperAGILE Localization of a Long GRB
  48. GRB 090323 Gemini-South Redshift
  49. GRB 090323: P60 Afterglow Confirmation
  50. GRB 090323: GROND Detection of the Afterglow and Photo-z
  51. GRB 090323: Possible XRT Counterpart
  52. IPN triangulation of GRB090323
  53. GRB 090320C: Fermi GBM Detection
  54. Fermi GBM and LAT detections of GRB 090323
  55. GRB 090320B: Fermi GBM detection.
  56. GRB 090319: Fermi GBM detection
  57. GRB 090320A: Fermi GBM detection
  58. GRB 090313: WSRT Radio Detection
  59. X-shooter observations of GRB 090313
  60. GRB 090315: Suzaku WAM observation of the prompt emission
  61. GRB 090313: VLT spectroscopy
  62. GRB090313: radio detection with the VLA
  63. Konus-Wind observation of GRB 090315
  64. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  65. GRB 090313, SMARTS optical/IR observations
  66. Further radio observation of GRB 090313
  67. Further Swift/UVOT observations of GRB 090313
  68. GRB 090313: detection with CARMA in 3mm band
  69. GRB090305B: MASTER-net prompt optical short burst observations
  70. Radio detection of GRB090313
  71. GRB 090313: MITSuME Okayama observation
  72. GRB 090313: Additional Gemini-S photometry
  73. GRB 090313: WSRT Radio Observations
  74. GRB 090313: Light curve steepening
  75. GRB 090313: TAROT La Silla observatory optical detection
  76. GRB 090313: Gemini-S photometry
  77. GRB 090313: Zadko Telescope observations
  78. GRB 090313 - PAIRITEL NIR detections
  79. GRB 090313: Gemini-S redshift
  80. GRB 090313 optical observations
  81. GRB 090313: Ongoing plateau phase
  82. GRB 090313: Swift-XRT refined analysis
  83. GRB 090313: Swift/UVOT upper limits
  84. GRB 090313: Faulkes Telescope North observations
  85. GRB 090313: Sustained optical brightness (correction)
  86. GRB 090306B: Confirmation of the X-ray afterglow
  87. GRB 090313: Swift-BAT refined analysis
  88. GRB 090313: Sustained optical brightness
  89. GRB 090313: SDSS object underlying the optical afterglow position
  90. GRB 090313, GROND observations
  91. GRB 090309, Swift-BAT lag analysis
  92. GRB 090313: Swift detection of a burst
  93. GRB 090313: Swift detection of a burst
  94. GRB 090313 OA candidate
  95. Swift trigger 346250 is probably not a burst
  96. GRB090310: Fermi GBM detection
  97. GRB 090205: Zadko Telescope late-time observations
  98. GRB 090309A: GROND upper limits
  99. GRB 090307A: TAROT Calern observatory optical observations
  100. GRB 090309: Swift/UVOT Upper Limits

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