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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 190204A: CALET Gamma-Ray Burst Monitor detection
  2. Retraction of IceCube GCN/AMON NOTICE 36142391_132143
  3. GRB 190202A: AstroSat CZTI detection
  4. GRB190202A: GROWTH-India detection of optical afterglow
  5. GRB 190203A: Swift-BAT refined analysis
  6. GRB 190204A: Swift-BAT refined analysis
  7. GRB 190202A: Xinglong-2.16m optical observations
  8. GRB 190202A: SAO RAS further optical observations
  9. Konus-Wind observation of GRB 190204A
  10. GRB 190204A: SAO RAS optical observations
  11. GRB 190204A: Mondy optical upper limit
  12. GRB 190203A: AstroSat CZTI detection
  13. GRB190203A: UVOT analysis
  14. GRB 190203A: COATLI Optical Observations
  15. GRB 190204A: Swift/UVOT Detection
  16. GRB 190204A: Enhanced Swift-XRT position
  17. GRB 190204A: COATLI Optical Detection of the Fading Afterglow
  18. GRB 190203A: Liverpool Telescope near-IR observations
  19. Konus-Wind observation of GRB 190203A
  20. GRB 190203A: Swift-XRT refined Analysis
  21. GRB 190204A: Swift-XRT refined Analysis
  22. GRB 190204A: AstroSat CZTI detection
  23. Swift Trigger 887541: MASTER inspect
  24. GRB 190204A: MAXI/GSC detection
  25. GRB 190202A: R and I band observation from HCT
  26. GRB 190204A: Swift detection of a burst with a possible optical counterpart
  27. Swift Trigger 887541: MASTER optical observation
  28. GRB 190203A: MASTER OT detection
  29. Swift Trigger 887541: Swift detection of Swift J1728.9-3613
  30. GRB 190203A: Enhanced Swift-XRT position
  31. GRB 190203A: SAO RAS optical observations, afterglow fading
  32. GRB 190203A: Koshka Zeiss-1000 optical upper limit
  33. GRB 190203A: Swift detection of a burst with an optical counterpart
  34. GRB 190202A: SAO RAS optical observations
  35. GRB 190202A: TSHAO optical observations
  36. GRB 190202A: NOT optical observations
  37. GRB 190202A: McDonald 0.8-m telescope optical observation
  38. GRB 190202A: Swift-XRT refined Analysis
  39. GRB 190202A: LCO-CTIO optical observations
  40. GRB 190202A: Fermi GBM observation
  41. Fermi GBM trigger 570825115/190202772 is not a GRB
  42. GRB 190202A, Swift-BAT refined analysis
  43. GRB 190202A: AGILE ratemeters detection
  44. GRB 190202A: Swift/UVOT Detection
  45. GRB 190202A: GOTO optical observations
  46. GRB 190202A: Enhanced Swift-XRT position
  47. GRB 190202A: Koshka Zeiss-1000 optical observations
  48. GRB 190202A: Swift detection of a burst with an optical counterpart
  49. Fermi GBM trigger 570716645/190201517 is not a GRB
  50. GRB 190131A: Insight-HXMT/HE detection
  51. GRB 190131A: AstroSat CZTI detection
  52. GRB 190126A: AstroSat CZTI detection
  53. Fermi GBM trigger 570659556/190131856 is not a GRB
  54. GRB 190129B: Insight-HXMT/HE detection
  55. GRB 190114C: JCMT SCUBA-2 sub-mm observations
  56. Improved IPN error box for GRB 190129B
  57. GRB 190129B: GOTO optical observations
  58. GRB 190129B: DDOTI Detection of the Possible Afterglow and Suggestion of Fading
  59. GRB 190129B: Swift/UVOT Upper Limits
  60. GRB 190129B: ePESSTO NTT optical observations
  61. GRB 190129B: AstroSat CZTI detection
  62. GRB 190129B: MASTER Global Robotic Net optical observation
  63. GRB 190129A: CALET Gamma-Ray Burst Monitor detection
  64. GRB 190129B: GROND possible host candidate
  65. GRB 190129B: Swift-XRT candidate afterglow detection
  66. GRB 190129B: Tiled Swift observations
  67. Fermi GBM Observations of IceCube-190124A
  68. GRB 190129A: Fermi GBM detection
  69. Konus-Wind observation of extremely bright GRB 190129B
  70. IPN Triangulation of GRB 190129B (long/extremely bright)
  71. INTEGRAL observation of IceCube-190124A
  72. GRB 190129A: MAXI/GSC detection
  73. Trigger 886496: Another Swift trigger on MAXI J1348-630
  74. Swift Trigger 886157: MASTER optical observation
  75. Trigger 886486: Swift detection of MAXI J1631-479
  76. Trigger 886266: Another Swift trigger on MAXI J1348-630
  77. Swift Trigger 886157: Swift detection of a new transient Swift J1728.9-3613
  78. INTEGRAL triggers from 8205 to 8211 are due to MAXI J1348-630, NOT to a GRB
  79. GRB 190114C: Optical follow-up from HCT
  80. Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
  81. Trigger 885845: A second Swift trigger on MAXI J1348-630
  82. Trigger 885807: Swift detection of MAXI J1348-630
  83. Search for counterparts to IceCube-190124A with IceCube
  84. Search for counterpart to IceCube-190124A with ANTARES
  85. GRB 190117A: AstroSat CZTI detection
  86. GRB 190122B: AstroSat CZTI detection
  87. Fermi-LAT Gamma-ray Observations of IceCube-190124A
  88. GRB 190123A: IKI-GRB-FuN optical upper limit
  89. GRB 190123A: NEXT-0.6m optical limit
  90. GRB 190114C: CHILESCOPE optical observations
  91. GRB 190123A: AROMA-N Optical Observation
  92. IceCube-190124A - IceCube observation of a high-energy neutrino candidate event
  93. GRB 190123A: Swift/UVOT Upper Limits
  94. Konus-Wind observation of GRB 190122A
  95. Konus-Wind of observation of GRB 190117A
  96. GRB 190123A: COATLI Optical Observations
  97. GRB 190123A: Swift-BAT refined analysis
  98. GRB 190121A: CALET Gamma-Ray Burst Monitor detection of a short burst
  99. GRB190123A: MITSuME Akeno optical upper limits
  100. GRB 190123A: GMG observational limit

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