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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"

14823 results found.

  1. GRB 161123A: MAXI/GSC detection
  2. GRB 161119A: MASTER-SAAO possible OT detection during Fermi Alert
  3. Swift Trigger 723124 is probably not a GRB
  4. Konus-Wind observation of GRB 161117A
  5. GRB 161117A: Fermi GBM detection/observation
  6. GRB 161117A: Swift/UVOT Detection
  7. Swift Trigger 722681 is probably not a GRB
  8. GRB 161117B: Swift detection of a burst
  9. GRB161117A: REM optical and NIR afterglow detection
  10. GRB 161117A: Swift detection of a burst with an optical counterpart
  11. GRB 161113A: Swift detection of a burst
  12. GRB 161109A: CALET Gamma-Ray Burst Monitor detection
  13. GRB 161106A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 161109A: Fermi-LAT detection
  15. GRB 161108A: Swift detection of a burst
  16. Fermi LAT Gamma-ray Observations of IceCube-161103
  17. GRB 161106A: Fermi GBM detection
  18. GRB 161104A: Gemini South optical observations
  19. Search for counterpart to IceCube-161103A with ANTARES
  20. GRB 161105A: Swift detection of a burst
  21. Fermi GBM Observations of IceCube-161103
  22. GRB 160928A: The first GRB detected by POLAR
  23. GRB 161104A: Swift detection of a short burst
  24. IceCube-161103: MASTER follow-up observations
  25. GRB161023A: AstroSat CZTI detection
  26. GRB 161023A: Swift-XRT afterglow detection
  27. Konus-Wind observation of GRB 161023A
  28. GRB 161023A (Integral trigger 7613) MASTER-Net bright OT detection
  29. Swift Trigger 718919 is not an astrophysical event.
  30. GRB 161022A: TAROT Calern observatory optical observations
  31. GRB 161022A: Swift detection of a burst
  32. GRB161017A: NOEMA detection of the millimetre afterglow
  33. GRB 161017A: GTC additional spectroscopy and refined redshift
  34. GRB 161017A: Swift/UVOT Detection
  35. GRB 161014A: Continued RATIR Optical and NIR Observations
  36. GRB 161017A: Swift detection of a burst with a bright optical afterglow
  37. GRB161017.74 MASTER-Net OT detection
  38. Konus-Wind observation of GRB 161015A
  39. GRB161015A: AstroSat CZTI detection
  40. GRB 161015A: Fermi GBM detection
  41. GRB 161015A: Fermi-LAT detection
  42. GRB161004A: Further analysis of the burst nature
  43. GRB 161014A: Swift/UVOT Detection
  44. GRB 161014A: Swift-XRT and UVOT afterglow detection
  45. GRB 161014A: Swift detection of a burst
  46. GRB 161010A: Swift/UVOT Possible Detection
  47. GRB 161010A: CALET Gamma-Ray Burst Monitor detection
  48. Konus-Wind observation of GRB 161010A
  49. GRB 161010A: Swift-XRT afterglow detection
  50. GRB 161011A: Swift detection of a burst
  51. GRB 161007A: Swift detection of a burst
  52. Konus-Wind observation of GRB 161004B
  53. GRB 161004B: CALET Gamma-Ray Burst Monitor detection
  54. GRB 160927A: CALET Gamma-Ray Burst Monitor ground detection
  55. GRB 161004B: Fermi GBM detection
  56. GRB161004B: AstroSat CZTI detection
  57. GRB 160917A: Lomonosov BDRG gamma ray detection
  58. GRB 160915A: Lomonosov BDRG gamma ray detection
  59. GRB 161004B: Swift detection of a burst
  60. GRB 161004A: Swift/UVOT Detection
  61. GRB 161004A: Swift detection of a burst with a possible optical counterpart
  62. Konus-Wind observation of GRB 161001A (short/hard ?)
  63. GRB 161001A: Fermi GBM detection
  64. GRB 161001A: Swift detection of a burst
  65. Possible radio detection of GRB 160910A with the GMRT
  66. GRB 160927A: Swift detection of a short hard burst
  67. GRB160910A: AstroSat CZTI detection
  68. XRT refined analysis for GRB 160925A
  69. GRB160824B: AstroSat CZTI detection
  70. GRB160917A: AstroSat CZTI detection
  71. GRB 160925A / Fermi 496473540: Global MASTER Net OT discovery
  72. GRB 160910A: 15 GHz detection from AMI
  73. GRB 160917A: Swift/UVOT Detection
  74. GRB 160917A: Swift detection of a burst
  75. GRB 160910A: Swift/UVOT Detection
  76. GRB 160912A: Swift/UVOT Weak Afterglow Detection
  77. GRB 160912A: Fermi GBM detection
  78. GRB 160910A: Global MASTER Net OT detection before LAT alert
  79. Konus-Wind observation of GRB 160910A
  80. GRB 160912A: Swift detection of a burst
  81. GRB 160910A: CALET Gamma-Ray Burst Monitor detection
  82. GRB 160910A: Afterglow detection from OSN
  83. GRB 160910A: Swift-XRT afterglow detection
  84. GRB 160908A: CALET Gamma-Ray Burst Monitor detection
  85. GRB 160910A: Fermi-LAT detection
  86. Konus-Wind observation of GRB 160905A
  87. GRB 160821B: 15 GHz upper limits from AMI
  88. GRB 160905A: Swift/UVOT Detection
  89. GRB 160816A: Possible radio afterglow detection at 15 GHz with AMI
  90. GRB 160905A: Fermi-LAT detection
  91. IceCube HESE 160814: MASTER OT J130845.02-323254.9 as the possible source of the high energy neutrino
  92. GRB 160905A: Swift detection of a burst with an optical counterpart
  93. Search for counterpart to IceCube-160814A with ANTARES
  94. GRB 160824B: Lomonosov BDRG gamma ray detection and MASTER limit
  95. GRB 160829A: Fermi GBM Detection
  96. GRB 160829A: Fermi-LAT detection of a short GRB
  97. GRB 160827A: Swift detection of a burst
  98. GRB 160824B: CALET Gamma-Ray Burst Monitor detection
  99. GRB 160825A: not localized by Swift
  100. GRB160821A: Astrosat CZTI (veto) detection

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