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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"

820 results found.

  1. GRB 220506A: Tiled Swift observations
  2. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  3. MAXI GRB220506.27: Global MASTER-Net observations report
  4. GRB 220310A: MITSuME Akeno optical observation
  5. IPN triangulation of GRB 220310A
  6. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  7. Konus-Wind detection of GRB 220310A
  8. GRB 220310A: GIT confirmation of optical afterglow.
  9. GRB 220310A: MASTER optical counterpart detection
  10. GRB 220310A: Swift ToO observations
  11. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  12. GRB 220310A: MAXI/GSC detection
  13. MAXI GRB220310.02: Global MASTER-Net observations report
  14. Fermi GRB 220304A: Global MASTER-Net observations report
  15. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  16. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  17. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  18. GRB 211227A: MAXI/GSC detection
  19. GRB 211225A: MITSuME Akeno optical upper limits
  20. MAXI GRB211225.14: Global MASTER-Net observations report
  21. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  22. GRB 211218A: MITSuME Akeno optical upper limits
  23. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  24. MAXI GRB211218.04: Global MASTER-Net observations report
  25. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  26. GRB 211115A: MAXI/GSC detection
  27. MAXI GRB210709.93: Global MASTER-Net observations report
  28. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  29. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  30. MAXI GRB210607.82: Global MASTER-Net observations report
  31. Konus-Wind detection of GRB 210602A
  32. Fermi GRB 210605A: Global MASTER-Net observations report
  33. MAXI GRB210602.50: Global MASTER-Net observations report
  34. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  35. GRB 210602A: MAXI/GSC detection
  36. GRB 210528B: DDOTI Upper Limits on the Afterglow
  37. MAXI GRB210528.95: Global MASTER-Net observations report
  38. GRB 210528B: MAXI/GSC detection
  39. MAXI GRB210521.54: Global MASTER-Net observations report
  40. GRB 210521A: MAXI/GSC detection
  41. Swift Detection of MAXI J1803-298 including an optical counterpart
  42. MAXI GRB210501.83: Global MASTER-Net observations report
  43. GRB 210402A: Swift/UVOT Upper Limits
  44. MAXI GRB210320.89: Global MASTER-Net observations report
  45. GRB 210320A: MAXI/GSC detection
  46. Konus-Wind detection of GRB 210222A
  47. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  48. GRB 210222A: MAXI/GSC detection
  49. SGR 1935+2154: MAXI/GSC detection
  50. NuEm-210111A: MAXI/GSC upper limit
  51. MAXI GRB210110.64: Global MASTER-Net observations report
  52. GRB 210110A: MAXI/GSC detection
  53. GRB 210109A: MAXI/GSC detection
  54. GRB 210102B: further Swift-XRT observations
  55. GRB 210102B: Assy optical afterglow identification
  56. GRB 210102B: Tiled Swift observations
  57. GRB 210102B: Assy optical observations
  58. GRB 210102B: Swift-XRT observations
  59. MAXI GRB210102.38: Global MASTER-Net observations report
  60. GRB 210102B: Tiled Swift observations
  61. GRB 210102B: MAXI/GSC detection
  62. GRB 201223A: Swift/UVOT Detection
  63. IceCube-201209A : MAXI/GSC upper limit
  64. MAXI GRB201021.68: Global MASTER-Net observations report
  65. GRB 201021B MAXI/GSC detection
  66. GRB 200903D: MAXI/GSC detection
  67. GRB 200809B: Fermi GBM detection
  68. GRB 200809B: Swift-XRT afterglow detection
  69. GRB 200809B: MAXI/GSC detection
  70. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  71. GRB 200615B: MAXI/GSC detection
  72. GRB 200517A: Swift-XRT Confirmation of afterglow
  73. Fermi GBM Sub-Threshold Detection of GRB 200517A
  74. GRB 200517A: Swift-XRT afterglow detection
  75. GRB 200514A: AstroSat CZTI detection
  76. GRB 200517A: Tiled Swift observations
  77. GRB 200517A: MAXI/GSC detection
  78. GRB 200514A: MITSuME Akeno optical upper limits
  79. GRB 200514A: CALET Gamma-Ray Burst Monitor detection
  80. GRB 200514A: MAXI/GSC detection
  81. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  82. SGR 1935+2154: MAXI/GSC detection
  83. GRB 200320B: MAXI/GSC detection
  84. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  85. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  86. GRB 200310A: MAXI/GSC detection
  87. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  88. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  89. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  90. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  92. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  93. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  94. GRB 200205A / Swift trigger 954304: VLT optical observations
  95. GRB 200205A: MAXI/GSC detection
  96. MAXI GRB200205.29: Global MASTER-Net observations report
  97. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  98. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  99. LIGO/Virgo S200115j: Coverage and upper limits from MAXI/GSC observations
  100. LIGO/Virgo S200114f: Coverage and upper limits from MAXI/GSC observations

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