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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"

1005 results found.

  1. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  2. SGR 1935+2154: MAXI/GSC detection
  3. GRB 200320B: MAXI/GSC detection
  4. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  6. GRB 200310A: MAXI/GSC detection
  7. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  9. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  10. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  11. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  12. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  13. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  14. GRB 200205A / Swift trigger 954304: VLT optical observations
  15. GRB 200205A: MAXI/GSC detection
  16. MAXI GRB200205.29: Global MASTER-Net observations report
  17. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  18. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  19. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  20. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  21. LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
  22. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  23. GRB 200105A: MAXI/GSC detection
  24. LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
  25. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  26. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations
  27. LIGO/Virgo S191213g: Coverage and upper limits from MAXI/GSC observations
  28. LIGO/Virgo S191205ah: Coverage and upper limits from MAXI/GSC observations
  29. LIGO/Virgo S191204r: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo S191129u: Coverage and upper limits from MAXI/GSC observations
  31. LIGO/Virgo S191110af: Coverage and upper limits from MAXI/GSC observations
  32. LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
  33. GRB 191106A: Swift/UVOT Upper Limits
  34. LIGO/Virgo S191105e: Coverage and upper limits from MAXI/GSC observations
  35. Fermi trigger No 594557071: Global MASTER-Net observations report
  36. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  37. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  38. LIGO/Virgo S190924h: Coverage and upper limits from MAXI/GSC observations
  39. LIGO/Virgo S190924h: Identification of a GW compact binary merger candidate
  40. LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations
  41. LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
  42. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  43. Swift Trigger 924641 is an outburst from MAXI J1807+132
  44. LIGO/Virgo S190910d: Coverage and upper limits from MAXI/GSC observations
  45. GRB 190823A: Swift-XRT afterglow detection
  46. LIGO/Virgo S190901ap: Coverage and upper limits from MAXI/GSC observations
  47. GRB 190828A: Swift-XRT observations
  48. GRB 190828A: Tiled Swift observations
  49. LIGO/Virgo S190828l: Coverage and upper limits from MAXI/GSC observations
  50. LIGO/Virgo S190828j: Coverage and upper limits from MAXI/GSC observations
  51. GRB 190828A: MAXI/GSC detection
  52. GRB 190823A: Swift-XRT observations
  53. GRB 190823A: Tiled Swift observations
  54. GRB 190823A: MAXI/GSC detection
  55. Fermi GBM-190816: Coverage and upper limits from MAXI/GSC observations
  56. LIGO/Virgo S190814bv: Coverage and upper limits from MAXI/GSC observations
  57. IPN triangulation of GRB 190805B
  58. LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations
  59. GRB 190805B: AstroSat CZTI detection
  60. GRB 190804B: Swift-XRT afterglow detection
  61. Konus-Wind observation of GRB 190805B
  62. GRB 190805B: Swift-XRT observations
  63. GRB 190805B: Fermi GBM detection
  64. GRB 190805B: Tiled Swift observations
  65. GRB 190804B: Swift-XRT observations
  66. GRB 190805B: MAXI/GSC detection
  67. MAXI GRB190804.33 Global MASTER-Net observations report
  68. GRB 190804B: Tiled Swift observations
  69. GRB 190804B: MAXI/GSC detection
  70. LIGO/Virgo S190728q: Coverage and upper limits from MAXI/GSC observations
  71. LIGO/Virgo S190727h: Coverage and upper limits from MAXI/GSC observations
  72. LIGO/Virgo S190720a: Coverage and upper limits from MAXI/GSC observations
  73. LIGO/Virgo S190718y: Coverage and upper limits from MAXI/GSC observations
  74. GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
  75. GRB 190708B: confirmation of the X-ray afterglow
  76. GRB 190714A: Tiled Swift observations
  77. GRB 190714A: MAXI/GSC detection
  78. GRB 190708B: Swift-XRT observations
  79. Konus-Wind observation of GRB 190708B
  80. GRB 190708B: Tiled Swift observations
  81. MAXI GRB190708.83 Global MASTER-Net observations report
  82. GRB 190708B: MAXI/GSC detection
  83. LIGO/Virgo S190707q: Coverage and upper limits from MAXI/GSC observations
  84. LIGO/Virgo S190706ai: Coverage and upper limits from MAXI/GSC observations
  85. GRB 190706A: MAXI/GSC detection
  86. LIGO/Virgo S190701ah: Coverage and upper limits from MAXI/GSC observations
  87. GRB 190701A: MAXI/GSC detection
  88. LIGO/Virgo S190630ag: Coverage and upper limits from MAXI/GSC observations
  89. IceCube Alert 190629.81 Global MASTER-Net observations report
  90. LIGO/Virgo S190602aq: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S190521r: Coverage and upper limits from MAXI/GSC observations
  92. IGO/Virgo S190521g: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo S190519bj: MAXI/GSC Observations
  94. LIGO/Virgo S190517h: MAXI/GSC Observations
  95. LIGO/Virgo S190513bm: MAXI/GSC Observations
  96. LIGO/Virgo S190512at: MAXI/GSC Observations
  97. LIGO/Virgo S190510g: MAXI/GSC Observations
  98. LIGO/Virgo S190503bf: MAXI/GSC Observations
  99. LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search
  100. LIGO/Virgo S190426c: MAXI/GSC Observations

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