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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"

788 results found.

  1. Konus-Wind detection of GRB 220310A
  2. GRB 220310A: GIT confirmation of optical afterglow.
  3. GRB 220310A: MASTER optical counterpart detection
  4. GRB 220310A: Swift ToO observations
  5. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  6. GRB 220310A: MAXI/GSC detection
  7. MAXI GRB220310.02: Global MASTER-Net observations report
  8. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  9. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  10. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  11. GRB 211227A: MAXI/GSC detection
  12. GRB 211225A: MITSuME Akeno optical upper limits
  13. MAXI GRB211225.14: Global MASTER-Net observations report
  14. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  15. GRB 211218A: MITSuME Akeno optical upper limits
  16. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  17. MAXI GRB211218.04: Global MASTER-Net observations report
  18. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 211115A: MAXI/GSC detection
  20. MAXI GRB210709.93: Global MASTER-Net observations report
  21. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  22. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  23. MAXI GRB210607.82: Global MASTER-Net observations report
  24. Konus-Wind detection of GRB 210602A
  25. MAXI GRB210602.50: Global MASTER-Net observations report
  26. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  27. GRB 210602A: MAXI/GSC detection
  28. GRB 210528B: DDOTI Upper Limits on the Afterglow
  29. MAXI GRB210528.95: Global MASTER-Net observations report
  30. GRB 210528B: MAXI/GSC detection
  31. MAXI GRB210521.54: Global MASTER-Net observations report
  32. GRB 210521A: MAXI/GSC detection
  33. Swift Detection of MAXI J1803-298 including an optical counterpart
  34. MAXI GRB210501.83: Global MASTER-Net observations report
  35. MAXI GRB210320.89: Global MASTER-Net observations report
  36. GRB 210320A: MAXI/GSC detection
  37. Konus-Wind detection of GRB 210222A
  38. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  39. GRB 210222A: MAXI/GSC detection
  40. SGR 1935+2154: MAXI/GSC detection
  41. NuEm-210111A: MAXI/GSC upper limit
  42. MAXI GRB210110.64: Global MASTER-Net observations report
  43. GRB 210110A: MAXI/GSC detection
  44. GRB 210109A: MAXI/GSC detection
  45. GRB 210102B: further Swift-XRT observations
  46. GRB 210102B: Assy optical afterglow identification
  47. GRB 210102B: Tiled Swift observations
  48. GRB 210102B: Assy optical observations
  49. GRB 210102B: Swift-XRT observations
  50. MAXI GRB210102.38: Global MASTER-Net observations report
  51. GRB 210102B: Tiled Swift observations
  52. GRB 210102B: MAXI/GSC detection
  53. IceCube-201209A : MAXI/GSC upper limit
  54. MAXI GRB201021.68: Global MASTER-Net observations report
  55. GRB 201021B MAXI/GSC detection
  56. GRB 200903D: MAXI/GSC detection
  57. GRB 200809B: Fermi GBM detection
  58. GRB 200809B: Swift-XRT afterglow detection
  59. GRB 200809B: MAXI/GSC detection
  60. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  61. GRB 200615B: MAXI/GSC detection
  62. GRB 200517A: Swift-XRT Confirmation of afterglow
  63. Fermi GBM Sub-Threshold Detection of GRB 200517A
  64. GRB 200517A: Swift-XRT afterglow detection
  65. GRB 200514A: AstroSat CZTI detection
  66. GRB 200517A: Tiled Swift observations
  67. GRB 200517A: MAXI/GSC detection
  68. GRB 200514A: MITSuME Akeno optical upper limits
  69. GRB 200514A: CALET Gamma-Ray Burst Monitor detection
  70. GRB 200514A: MAXI/GSC detection
  71. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  72. SGR 1935+2154: MAXI/GSC detection
  73. GRB 200320B: MAXI/GSC detection
  74. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  76. GRB 200310A: MAXI/GSC detection
  77. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  78. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  80. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  81. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  83. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  84. GRB 200205A / Swift trigger 954304: VLT optical observations
  85. GRB 200205A: MAXI/GSC detection
  86. MAXI GRB200205.29: Global MASTER-Net observations report
  87. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  88. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  89. LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
  90. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations
  92. LIGO/Virgo S200112r: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo S200105ae: Coverage and upper limits from MAXI/GSC observations
  94. GRB 200105A: MAXI/GSC detection
  95. LIGO/Virgo S191222n: Coverage and upper limits from MAXI/GSC observations
  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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