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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 161109A: Swift-XRT observations
  2. GRB 161108A: MITSuME Okayama upper limits
  3. IceCube-161103: CALET Gamma-Ray Burst Monitor upper limits
  4. GRB 161106A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 161108A: TSHAO optical observations
  6. GRB 161108A: Swift/UVOT Upper Limits
  7. GRB 161109A: Tiled Swift observations
  8. GRB 161105A: Swift/UVOT Upper Limits
  9. GRB 161109A: Fermi GBM observation
  10. GRB 161109A: Fermi-LAT detection
  11. GRB 161106A: Lomonosov BDRG gamma ray discovery
  12. GRB 161108A: TAROT Calern observatory optical observations
  13. GRB 161105A: TAROT La Silla observatory optical observations
  14. GRB 161108A, Swift-BAT refined analysis
  15. GRB 161108A: NOT redshift
  16. GRB 161108A: RATIR Afterglow Confirmation
  17. GRB 161108A: Swift-XRT refined Analysis
  18. GRB 161108A: Enhanced Swift-XRT position
  19. GRB 161108A: NOT candidate afterglow
  20. GRB 161108A: Swift detection of a burst
  21. Fermi LAT Gamma-ray Observations of IceCube-161103
  22. GRB 161022A: 15 GHz upper limits from AMI
  23. GRB 161017A: 15 GHz upper limits from AMI
  24. GRB 161103A: an ultra-long GRB detected by Konus-Wind
  25. GRB 161106A: Fermi GBM detection
  26. IceCube-161103: Konus-Wind upper limits
  27. GRB 161105A: Swift-XRT refined Analysis
  28. GRB 161104A: Gemini South optical observations
  29. GRB 161105A: Swift-BAT refined analysis
  30. GRB 161105A: Enhanced Swift-XRT position
  31. Search for counterpart to IceCube-161103A with ANTARES
  32. GRB 161105A: MASTER-IAC early optical observations
  33. GRB 161104A: GROND observations
  34. GRB 161105A: Swift detection of a burst
  35. GRB 161104A: Swift/UVOT Upper Limits
  36. GRB 161104A, Swift-BAT refined analysis
  37. GRB 161104A: Swift-XRT refined Analysis
  38. Fermi GBM Observations of IceCube-161103
  39. GRB 160928A: The first GRB detected by POLAR
  40. IceCube-161103: Swift-XRT observations
  41. GRB 161104A: Enhanced Swift-XRT position
  42. GRB 161104A: Swift detection of a short burst
  43. INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161103
  44. IceCube-161103: MASTER follow-up observations
  45. HAWC follow up of IceCube-161103
  46. IceCube-161103: IceCube observation of a very-high-energy neutrino
  47. GRB 161020A: Fermi GBM observation
  48. Fermi GBM trigger 499467682/161029876 is not a GRB
  49. GRB 161015A: 15 GHz upper limits from AMI
  50. GRB 161014A: 15 GHz upper limits from AMI
  51. GRB161023A: AstroSat CZTI detection
  52. GRB 161023A: GROND Observations
  53. GRB 161023A: Swift-XRT afterglow detection
  54. Konus-Wind observation of GRB 161023A
  55. GRB 161023A: TAROT La Silla observatory optical observations
  56. GRB 161023A: Zadko observatory - Gingin optical observations
  57. GRB 161023A: Watcher optical observations
  58. GRB 161023A: LCOGT-FTS optical observations
  59. GRB 161023A: Swift ToO observations
  60. Radio upper limit on the GRB 161011A with the GMRT
  61. GRB 161023A VLT/X-shooter redshift
  62. GRB 161023A: A long GRB detected by INTEGRAL
  63. GRB 161023A (Integral trigger 7613) MASTER-Net bright OT detection
  64. Swift Trigger 718919 is not an astrophysical event.
  65. GRB 161022A: Swift-BAT refined analysis
  66. Swift Trigger 718766 is not an astrophysical event.
  67. GRB 161022A: RATIR Optical and NIR Observations
  68. GRB 161022A: Swift/UVOT Upper Limits
  69. GRB 161022A: Fermi GBM observation
  70. GRB 161022A: NOT optical observations
  71. GRB 161022A: Enhanced Swift-XRT position
  72. Konus-Wind observation of GRB 161020B
  73. GRB 161022A: Swift-XRT refined Analysis
  74. IPN Triangulation of GRB 161020B
  75. GRB 161022A: LT observations
  76. GRB 161022A: TAROT Calern observatory optical observations
  77. GRB 161022A: Prompt enhanced Swift-XRT position
  78. GRB 161022A: Swift detection of a burst
  79. GRB 161020A: A long GRB detected by INTEGRAL
  80. GRB 161015A: further Swift-XRT follow-up observations
  81. GRB 161011A: 15 GHz upper limits from AMI
  82. GRB 161007A: 15 GHz upper limits from AMI
  83. Konus-Wind observation of GRB 161017A
  84. GRB161017A: NOEMA detection of the millimetre afterglow
  85. GRB 161017A: LT optical observations
  86. GRB161017A optical R band observations with SARA-RM
  87. GRB 161017A: TNG spectroscopy and redshift confirmation
  88. GRB 161017A: GTC additional spectroscopy and refined redshift
  89. GRB 161017A: Swift-BAT refined analysis
  90. GRB 161017A: Lomonosov Gamma Ray and MASTER Optical prompt observations
  91. GRB 161017A: Swift/UVOT Detection
  92. GRB 161017A: Swift-XRT refined Analysis
  93. GRB161017A: optical observations with 1-m LCOGT McDonald
  94. GRB 161017A: TNG optical observations
  95. GRB 161017A: MITSuME Akeno Optical Observation
  96. GRB 161017A: Redshift from GTC
  97. GRB 161017A: Fermi GBM observation
  98. GRB 161017A: Enhanced Swift-XRT position
  99. GRB 161014A: Continued RATIR Optical and NIR Observations
  100. GRB 161015A: Swift/UVOT observations

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