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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"

14247 results found.

  1. GRB 090407: Swift detection of a burst
  2. GRB 090404: millimeter detection
  3. GRB 090404: nIR observations at Calar Alto
  4. GRB 090405: Fermi GBM Detection
  5. GRB 090403: Fermi GBM detection
  6. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  7. GRB 090404: Swift detection of a burst
  8. GRB 090401B: AGILE refined analysis
  9. GRB 090331: Fermi GBM detection
  10. AGILE Gamma-ray detection of GRB 090401B
  11. Swift/UVOT detection of GRB090401B
  12. GRB 090401B: Swift detection of a burst
  13. GRB 090323: Further TLS detections - a break?
  14. GRB 090401: Swift detection of a burst
  15. GRB 090328: Radio afterglow detection
  16. GRB 090326: Fermi GBM detection
  17. GRB 090328: BOOTES-3 optical observations
  18. GRB 090328B: Fermi GBM Detection
  19. GRB 090330: Fermi GBM detection
  20. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  21. GRB 090323: WSRT Radio Detection
  22. GRB 090328: Possible Swift/XRT detection
  23. Fermi LAT and GBM detections of GRB090328
  24. GRB 090323: Radio afterglow detection
  25. GRB 090323: TLS detection at 5 days, no break
  26. GRB 090327: Fermi GBM detection
  27. GRB 090323 TLS detection - still bright
  28. GRB 090323: UVOT Detection of Afterglow
  29. GRB 090323: GROND Detection of the Afterglow and Photo-z
  30. GRB 090320C: Fermi GBM Detection
  31. GRB 090320B: Fermi GBM detection.
  32. GRB 090319: Fermi GBM detection
  33. GRB 090320A: Fermi GBM detection
  34. GRB 090313: WSRT Radio Detection
  35. X-shooter observations of GRB 090313
  36. GRB 090313: VLT spectroscopy
  37. GRB090313: radio detection with the VLA
  38. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  39. GRB 090313: detection with CARMA in 3mm band
  40. Radio detection of GRB090313
  41. GRB 090313: TAROT La Silla observatory optical detection
  42. GRB 090313 optical observations
  43. GRB 090313: Swift/UVOT upper limits
  44. GRB 090313: Faulkes Telescope North observations
  45. GRB 090313: Swift detection of a burst
  46. GRB 090313: Swift detection of a burst
  47. GRB090310: Fermi GBM detection
  48. GRB090305B: Fermi GBM detection
  49. GRB 090309B: Fermi GBM detection
  50. GRB 090309: Swift detection of a burst
  51. GRB 090308B: Fermi GBM detection
  52. GRB 090307B: Fermi GBM detection
  53. GRB 090306C: Fermi GBM detection
  54. GRB 090308: Swift detection of a burst
  55. GRB 090306B: Burst detection from Swift-BAT slew data
  56. Swift Trigger 345551 is probably not a GRB
  57. GRB 090306: Swift detection of a possible burst
  58. GRB 090305: Swift-XRT refined analysis
  59. GRB 090305: Swift detection of a short burst
  60. GRB 090303: Fermi GBM detection
  61. GRB 090304: Fermi GBM detection
  62. GRB 090228B: Fermi GBM detection
  63. GRB 090301B: Fermi GBM detection
  64. GRB 090227B: Fermi GBM detection
  65. GRB 090301: Swift detection of a burst
  66. GRB 090228: Fermi GBM detection
  67. GRB 090227: Fermi GBM detection
  68. GRB 090206: Fermi GBM detection
  69. GRB 081211B: Nearby cluster
  70. GRB 090222: Fermi GBM detection
  71. GRB 090219: Fermi GBM detection
  72. GRB 090217: Suzaku WAM observation of the prompt emission
  73. GRB090217: XRT analysis
  74. GRB 090213: Fermi GBM detection
  75. GRB090217: Fermi-LAT Detection
  76. GRB 090217: Fermi GBM detection
  77. SGR activity seen by BAT during ICSP Ionospheric Events
  78. GRB 090129: Fermi GBM detection
  79. GRB 090205: GROND observations and photometric redshift estimate
  80. GRB 090205: Swift detection of a burst
  81. GRB 090202: Fermi GBM detection
  82. GRB 090131: Fermi GBM detection
  83. GRB 090201: VLT NIR observations
  84. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  85. GRB 090201: Swift detection of a burst
  86. GRB 090126A: Swift/UVOT Upper Limits
  87. GRB 090129: Swift detection of a burst
  88. GRB 090126C: Fermi GBM detection
  89. GRB 090126B: Fermi GBM detection
  90. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  91. GRB 090118: no afterglow candidate
  92. GRB 090123: GROND detection
  93. 1E1547.0-5408: Swift detection of dust halo
  94. GRB 090123: Swift/UVOT Observations
  95. GRB 090123: Swift detection of a burst
  96. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  97. Trigger 340734: Swift detection of a possible short burst
  98. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  99. GRB 090118: Possible burst detection from Swift-BAT slew data
  100. GRB 090117B : Fermi GBM detection

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