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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 090323 Gemini-South Redshift
  2. GRB 090323: P60 Afterglow Confirmation
  3. GRB 090323: GROND Detection of the Afterglow and Photo-z
  4. SGR J1550-5418: two Fermi GBM triggers on March 22
  5. GRB 090323: Possible XRT Counterpart
  6. IPN triangulation of GRB090323
  7. GRB 090320C: Fermi GBM Detection
  8. Fermi GBM and LAT detections of GRB 090323
  9. GRB 090320B: Fermi GBM detection.
  10. GRB 090319: Fermi GBM detection
  11. GRB 090320A: Fermi GBM detection
  12. Further 15GHz observations of GRB090313
  13. GRB 090313: WSRT Radio Detection
  14. X-shooter observations of GRB 090313
  15. A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418
  16. GRB 090315: Suzaku WAM observation of the prompt emission
  17. GRB 090313: VLT spectroscopy
  18. GRB090313: radio detection with the VLA
  19. Konus-Wind observation of GRB 090315
  20. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  21. GRB 090313, SMARTS optical/IR observations
  22. Further radio observation of GRB 090313
  23. Further Swift/UVOT observations of GRB 090313
  24. GRB 090313: detection with CARMA in 3mm band
  25. GRB090305B: MASTER-net prompt optical short burst observations
  26. Radio detection of GRB090313
  27. GRB 090313: MITSuME Okayama observation
  28. GRB 090313: Additional Gemini-S photometry
  29. GRB 090313: WSRT Radio Observations
  30. GRB 090313: Light curve steepening
  31. GRB 090313: TAROT La Silla observatory optical detection
  32. GRB 090313: Gemini-S photometry
  33. GRB 090313: Zadko Telescope observations
  34. GRB 090313 - PAIRITEL NIR detections
  35. GRB 090313: Gemini-S redshift
  36. GRB 090313 optical observations
  37. GRB 090313: Ongoing plateau phase
  38. GRB 090313: Swift-XRT refined analysis
  39. GRB 090313: Swift/UVOT upper limits
  40. GRB 090313: Faulkes Telescope North observations
  41. GRB 090313: Sustained optical brightness (correction)
  42. GRB 090306B: Confirmation of the X-ray afterglow
  43. GRB 090313: Swift-BAT refined analysis
  44. GRB 090313: Sustained optical brightness
  45. GRB 090313: SDSS object underlying the optical afterglow position
  46. GRB 090313, GROND observations
  47. GRB 090309, Swift-BAT lag analysis
  48. GRB 090313: Swift detection of a burst
  49. GRB 090313: Swift detection of a burst
  50. GRB 090313 OA candidate
  51. Swift trigger 346250 is probably not a burst
  52. GRB090310: Fermi GBM detection
  53. GRB 090205: Zadko Telescope late-time observations
  54. GRB 090309A: GROND upper limits
  55. GRB 090307A: TAROT Calern observatory optical observations
  56. GRB 090309: Swift/UVOT Upper Limits
  57. GRB090305B: Fermi GBM detection
  58. GRB 090309B: Fermi GBM detection
  59. GRB 090309: Swift-XRT refined analysis
  60. GRB 090309: Enhanced Swift-XRT position
  61. GRB 090306B: INTEGRAL SPI-ACS light curve
  62. GRB 090309, Swift-BAT refined analysis
  63. GRB 090308: GROND observations
  64. GRB 090308: Gemini GMOS Observations
  65. GRB 090309: Swift detection of a burst
  66. GRB 090308B: Fermi GBM detection
  67. GRB 090308: Swift/UVOT Upper Limits
  68. GRB 090307B: Fermi GBM detection
  69. GRB 090306C: Fermi GBM detection
  70. GRB 090307: GROND Upper Limits
  71. GRB 090306B: GROND Upper Limits
  72. GRB 090305C: Suzaku WAM observation of the prompt emission
  73. GRB 090308: Swift-XRT refined analysis
  74. Radio observation of GRB 090201 with ATCA
  75. Radio observation of GRB 090117 with ATCA
  76. Radio observation of GRB 081226b with ATCA
  77. Radio observation of GRB 081226a with ATCA
  78. Radio observation of GRB 081007 with ATCA
  79. ATCA observation of SGR J1550-5418
  80. GRB 090308: Swift-BAT refined analysis
  81. GRB 090308: Swift detection of a burst
  82. GRB 090306B: Possible XRT afterglow
  83. GRB 090307: Swift-XRT afterglow confirmation and analysis
  84. GRB 090307: Swift-BAT refined analysis of trigger 345551
  85. GRB 090306B: Burst detection from Swift-BAT slew data
  86. Swift Trigger 345551 is probably not a GRB
  87. Swift-BAT trigger 345396 is not a GRB
  88. IPN localization of short GRB 090305C
  89. Fermi GBM trigger 090305784 is not a GRB
  90. GRB 090306: Swift detection of a possible burst
  91. GRB 090305: Swift/UVOT Upper Limits
  92. GRB 090305: Swift-XRT refined analysis
  93. GRB 090305, Swift-BAT refined analysis
  94. GRB 090227A: Suzaku WAM observation of the prompt emission
  95. GRB 090305: Magellan confirmation of the optical afterglow
  96. GRB090305: GMOS-S Candidate Optical Afterglow
  97. GRB 090305: Swift detection of a short burst
  98. GRB 090303: Fermi GBM detection
  99. GRB 090304: Fermi GBM detection
  100. GRB 090301A: Suzaku WAM observation of the prompt emission

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