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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 090328: Possible Swift/XRT detection
  2. Fermi LAT and GBM detections of GRB090328
  3. GRB 090323: Radio afterglow detection
  4. GRB 090323: Additional Lick observations
  5. GRB 090323: TLS detection at 5 days, no break
  6. GRB 090327: Fermi GBM detection
  7. GRB 090323: Faulkes Telescope South Observations
  8. GRB 090320B: MASTER-Net prompt optical observations
  9. GRB 090323: RTT150 optical observations
  10. GRB 090323: Lick observations
  11. GRB 090323: Fermi GBM Spectral Analysis
  12. GRB 090323: Optical observation of xinglong TNT
  13. GRB 090323 TLS detection - still bright
  14. GRB 090323: UVOT Detection of Afterglow
  15. GRB 090323: Swift-XRT refined analysis
  16. Konus-Wind observation of GRB 090323
  17. GRB 090324: SuperAGILE Localization of a Long GRB
  18. GRB 090323 Gemini-South Redshift
  19. GRB 090323: P60 Afterglow Confirmation
  20. GRB 090323: GROND Detection of the Afterglow and Photo-z
  21. SGR J1550-5418: two Fermi GBM triggers on March 22
  22. GRB 090323: Possible XRT Counterpart
  23. IPN triangulation of GRB090323
  24. GRB 090320C: Fermi GBM Detection
  25. Fermi GBM and LAT detections of GRB 090323
  26. GRB 090320B: Fermi GBM detection.
  27. GRB 090319: Fermi GBM detection
  28. GRB 090320A: Fermi GBM detection
  29. Further 15GHz observations of GRB090313
  30. GRB 090313: WSRT Radio Detection
  31. X-shooter observations of GRB 090313
  32. A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418
  33. GRB 090315: Suzaku WAM observation of the prompt emission
  34. GRB 090313: VLT spectroscopy
  35. GRB090313: radio detection with the VLA
  36. Konus-Wind observation of GRB 090315
  37. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  38. GRB 090313, SMARTS optical/IR observations
  39. Further radio observation of GRB 090313
  40. Further Swift/UVOT observations of GRB 090313
  41. GRB 090313: detection with CARMA in 3mm band
  42. GRB090305B: MASTER-net prompt optical short burst observations
  43. Radio detection of GRB090313
  44. GRB 090313: MITSuME Okayama observation
  45. GRB 090313: Additional Gemini-S photometry
  46. GRB 090313: WSRT Radio Observations
  47. GRB 090313: Light curve steepening
  48. GRB 090313: TAROT La Silla observatory optical detection
  49. GRB 090313: Gemini-S photometry
  50. GRB 090313: Zadko Telescope observations
  51. GRB 090313 - PAIRITEL NIR detections
  52. GRB 090313: Gemini-S redshift
  53. GRB 090313 optical observations
  54. GRB 090313: Ongoing plateau phase
  55. GRB 090313: Swift-XRT refined analysis
  56. GRB 090313: Swift/UVOT upper limits
  57. GRB 090313: Faulkes Telescope North observations
  58. GRB 090313: Sustained optical brightness (correction)
  59. GRB 090306B: Confirmation of the X-ray afterglow
  60. GRB 090313: Swift-BAT refined analysis
  61. GRB 090313: Sustained optical brightness
  62. GRB 090313: SDSS object underlying the optical afterglow position
  63. GRB 090313, GROND observations
  64. GRB 090309, Swift-BAT lag analysis
  65. GRB 090313: Swift detection of a burst
  66. GRB 090313: Swift detection of a burst
  67. GRB 090313 OA candidate
  68. Swift trigger 346250 is probably not a burst
  69. GRB090310: Fermi GBM detection
  70. GRB 090205: Zadko Telescope late-time observations
  71. GRB 090309A: GROND upper limits
  72. GRB 090307A: TAROT Calern observatory optical observations
  73. GRB 090309: Swift/UVOT Upper Limits
  74. GRB090305B: Fermi GBM detection
  75. GRB 090309B: Fermi GBM detection
  76. GRB 090309: Swift-XRT refined analysis
  77. GRB 090309: Enhanced Swift-XRT position
  78. GRB 090306B: INTEGRAL SPI-ACS light curve
  79. GRB 090309, Swift-BAT refined analysis
  80. GRB 090308: GROND observations
  81. GRB 090308: Gemini GMOS Observations
  82. GRB 090309: Swift detection of a burst
  83. GRB 090308B: Fermi GBM detection
  84. GRB 090308: Swift/UVOT Upper Limits
  85. GRB 090307B: Fermi GBM detection
  86. GRB 090306C: Fermi GBM detection
  87. GRB 090307: GROND Upper Limits
  88. GRB 090306B: GROND Upper Limits
  89. GRB 090305C: Suzaku WAM observation of the prompt emission
  90. GRB 090308: Swift-XRT refined analysis
  91. Radio observation of GRB 090201 with ATCA
  92. Radio observation of GRB 090117 with ATCA
  93. Radio observation of GRB 081226b with ATCA
  94. Radio observation of GRB 081226a with ATCA
  95. Radio observation of GRB 081007 with ATCA
  96. ATCA observation of SGR J1550-5418
  97. GRB 090308: Swift-BAT refined analysis
  98. GRB 090308: Swift detection of a burst
  99. GRB 090306B: Possible XRT afterglow
  100. GRB 090307: Swift-XRT afterglow confirmation and analysis

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