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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"

927 results found.

  1. GRB 211227A: MAXI/GSC detection
  2. GRB 211225A: MITSuME Akeno optical upper limits
  3. MAXI GRB211225.14: Global MASTER-Net observations report
  4. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  5. GRB 211218A: MITSuME Akeno optical upper limits
  6. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  7. MAXI GRB211218.04: Global MASTER-Net observations report
  8. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  9. GRB 211115A: MAXI/GSC detection
  10. MAXI GRB210709.93: Global MASTER-Net observations report
  11. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  12. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  13. MAXI GRB210607.82: Global MASTER-Net observations report
  14. Konus-Wind detection of GRB 210602A
  15. MAXI GRB210602.50: Global MASTER-Net observations report
  16. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  17. GRB 210602A: MAXI/GSC detection
  18. GRB 210528B: DDOTI Upper Limits on the Afterglow
  19. MAXI GRB210528.95: Global MASTER-Net observations report
  20. GRB 210528B: MAXI/GSC detection
  21. MAXI GRB210521.54: Global MASTER-Net observations report
  22. GRB 210521A: MAXI/GSC detection
  23. GRB 210504A: BOOTES-4/MET optical upper limit
  24. Swift Detection of MAXI J1803-298 including an optical counterpart
  25. MAXI GRB210501.83: Global MASTER-Net observations report
  26. MAXI GRB210320.89: Global MASTER-Net observations report
  27. GRB 210320A: MAXI/GSC detection
  28. Konus-Wind detection of GRB 210222A
  29. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  30. GRB 210222A: MAXI/GSC detection
  31. Fermi-LAT Gamma-ray Observations of IceCube-210210A
  32. SGR 1935+2154: MAXI/GSC detection
  33. NuEm-210111A: MAXI/GSC upper limit
  34. MAXI GRB210110.64: Global MASTER-Net observations report
  35. GRB 210110A: MAXI/GSC detection
  36. GRB 210109A: MAXI/GSC detection
  37. GRB 210102B: further Swift-XRT observations
  38. GRB 210102B: Assy optical afterglow identification
  39. GRB 210102B: Tiled Swift observations
  40. GRB 210102B: Assy optical observations
  41. GRB 210102B: Swift-XRT observations
  42. MAXI GRB210102.38: Global MASTER-Net observations report
  43. GRB 210102B: Tiled Swift observations
  44. GRB 210102B: MAXI/GSC detection
  45. IceCube-201209A : MAXI/GSC upper limit
  46. GRB 201026A: Swift/UVOT Upper Limits
  47. GRB 201020A: Swift/UVOT Observations
  48. HAWC-201019A: No Neutrino Counterpart detected with ANTARES
  49. MAXI GRB201021.68: Global MASTER-Net observations report
  50. GRB 201021B MAXI/GSC detection
  51. GRB 200903D: MAXI/GSC detection
  52. Swift GRB 200819A: Global MASTER-Net observations report
  53. GRB 200809B: Fermi GBM detection
  54. GRB 200809B: Swift-XRT afterglow detection
  55. GRB 200809B: MAXI/GSC detection
  56. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  57. GRB 200615B: MAXI/GSC detection
  58. GRB 200517A: Swift-XRT Confirmation of afterglow
  59. Fermi GBM Sub-Threshold Detection of GRB 200517A
  60. GRB 200517A: Swift-XRT afterglow detection
  61. GRB 200514A: AstroSat CZTI detection
  62. GRB 200517A: Tiled Swift observations
  63. GRB 200517A: MAXI/GSC detection
  64. GRB 200514A: MITSuME Akeno optical upper limits
  65. GRB 200514A: CALET Gamma-Ray Burst Monitor detection
  66. GRB 200514A: MAXI/GSC detection
  67. GRB 200505A: AGILE detection
  68. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  69. SGR 1935+2154: MAXI/GSC detection
  70. GRB 200324A: Swift/UVOT Upper Limits
  71. GRB 200320B: MAXI/GSC detection
  72. Fermi trigger No 606263732: Global MASTER-Net observations report
  73. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  74. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  75. GRB 200310A: MAXI/GSC detection
  76. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  77. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  78. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  80. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  81. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  82. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  83. GRB 200205A / Swift trigger 954304: VLT optical observations
  84. GRB 200205A: MAXI/GSC detection
  85. MAXI GRB200205.29: Global MASTER-Net observations report
  86. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  87. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  88. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  89. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  90. LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  92. GRB 200105A: MAXI/GSC detection
  93. GRB 191221B: Swift/UVOT Detection
  94. LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
  95. LIGO/Virgo S191213g: Swift UVOT/XRT observations of three ZTF sources
  96. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  97. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations
  98. LIGO/Virgo S191213g: Coverage and upper limits from MAXI/GSC observations
  99. LIGO/Virgo S191205ah: Coverage and upper limits from MAXI/GSC observations
  100. LIGO/Virgo S191204r: Coverage and upper limits from MAXI/GSC observations

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