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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 090313: TAROT La Silla observatory optical detection
  2. GRB 090313: Gemini-S photometry
  3. GRB 090313: Zadko Telescope observations
  4. GRB 090313 - PAIRITEL NIR detections
  5. GRB 090313: Gemini-S redshift
  6. GRB 090313 optical observations
  7. GRB 090313: Ongoing plateau phase
  8. GRB 090313: Swift-XRT refined analysis
  9. GRB 090313: Swift/UVOT upper limits
  10. GRB 090313: Faulkes Telescope North observations
  11. GRB 090313: Sustained optical brightness (correction)
  12. GRB 090306B: Confirmation of the X-ray afterglow
  13. GRB 090313: Swift-BAT refined analysis
  14. GRB 090313: Sustained optical brightness
  15. GRB 090313: SDSS object underlying the optical afterglow position
  16. GRB 090313, GROND observations
  17. GRB 090309, Swift-BAT lag analysis
  18. GRB 090313: Swift detection of a burst
  19. GRB 090313: Swift detection of a burst
  20. GRB 090313 OA candidate
  21. Swift trigger 346250 is probably not a burst
  22. GRB090310: Fermi GBM detection
  23. GRB 090205: Zadko Telescope late-time observations
  24. GRB 090309A: GROND upper limits
  25. GRB 090307A: TAROT Calern observatory optical observations
  26. GRB 090309: Swift/UVOT Upper Limits
  27. GRB090305B: Fermi GBM detection
  28. GRB 090309B: Fermi GBM detection
  29. GRB 090309: Swift-XRT refined analysis
  30. GRB 090309: Enhanced Swift-XRT position
  31. GRB 090306B: INTEGRAL SPI-ACS light curve
  32. GRB 090309, Swift-BAT refined analysis
  33. GRB 090308: GROND observations
  34. GRB 090308: Gemini GMOS Observations
  35. GRB 090309: Swift detection of a burst
  36. GRB 090308B: Fermi GBM detection
  37. GRB 090308: Swift/UVOT Upper Limits
  38. GRB 090307B: Fermi GBM detection
  39. GRB 090306C: Fermi GBM detection
  40. GRB 090307: GROND Upper Limits
  41. GRB 090306B: GROND Upper Limits
  42. GRB 090305C: Suzaku WAM observation of the prompt emission
  43. GRB 090308: Swift-XRT refined analysis
  44. Radio observation of GRB 090201 with ATCA
  45. Radio observation of GRB 090117 with ATCA
  46. Radio observation of GRB 081226b with ATCA
  47. Radio observation of GRB 081226a with ATCA
  48. Radio observation of GRB 081007 with ATCA
  49. ATCA observation of SGR J1550-5418
  50. GRB 090308: Swift-BAT refined analysis
  51. GRB 090308: Swift detection of a burst
  52. GRB 090306B: Possible XRT afterglow
  53. GRB 090307: Swift-XRT afterglow confirmation and analysis
  54. GRB 090307: Swift-BAT refined analysis of trigger 345551
  55. GRB 090306B: Burst detection from Swift-BAT slew data
  56. Swift Trigger 345551 is probably not a GRB
  57. Swift-BAT trigger 345396 is not a GRB
  58. IPN localization of short GRB 090305C
  59. Fermi GBM trigger 090305784 is not a GRB
  60. GRB 090306: Swift detection of a possible burst
  61. GRB 090305: Swift/UVOT Upper Limits
  62. GRB 090305: Swift-XRT refined analysis
  63. GRB 090305, Swift-BAT refined analysis
  64. GRB 090227A: Suzaku WAM observation of the prompt emission
  65. GRB 090305: Magellan confirmation of the optical afterglow
  66. GRB090305: GMOS-S Candidate Optical Afterglow
  67. GRB 090305: Swift detection of a short burst
  68. GRB 090303: Fermi GBM detection
  69. GRB 090304: Fermi GBM detection
  70. GRB 090301A: Suzaku WAM observation of the prompt emission
  71. Konus-RF catches first GRB and SGR bursts
  72. GRB 090228B: Fermi GBM detection
  73. Konus-Wind observation of bright short GRB 090227B
  74. IPN localization of short bright GRB 090227B
  75. Konus-Wind observation of GRB 090301A
  76. GRB 090301A: Swift-BAT refined analysis
  77. GRB 090301B: Fermi GBM detection
  78. GRB 090227B: Fermi GBM detection
  79. GRB 090301: Swift detection of a burst
  80. Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
  81. GRB 090228: Fermi GBM detection
  82. GRB 090227: Fermi GBM detection
  83. GRB 090206: Fermi GBM detection
  84. SGR J1550-5418
  85. GRB 081211B: Nearby cluster
  86. Ongoing activity of AXP/SGR 1E1547.0-5408
  87. GRB 090222: Fermi GBM detection
  88. GRB 090219: Fermi GBM detection
  89. Swift Restored
  90. Swift Trigger 343319 is not a GRB
  91. GRB 090217: Suzaku WAM observation of the prompt emission
  92. GRB090217: XRT analysis
  93. Konus-Wind observation of GRB 090217
  94. IPN localization of GRB 090217
  95. GRB 090213: Fermi GBM detection
  96. GRB090217: Fermi-LAT Detection
  97. GRB 090217: Fermi GBM detection
  98. SGR activity seen by BAT during ICSP Ionospheric Events
  99. Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408
  100. GRB 090207 - Fermi GBM Observations

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