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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"

939 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 220411A: AstroSat CZTI detection
  5. Fermi GRB 220411A: Global MASTER-Net observations report
  6. GRB 220310A: MITSuME Akeno optical observation
  7. IPN triangulation of GRB 220310A
  8. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  9. Konus-Wind detection of GRB 220310A
  10. GRB 220310A: GIT confirmation of optical afterglow.
  11. GRB 220310A: MASTER optical counterpart detection
  12. GRB 220310A: Swift ToO observations
  13. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 220310A: MAXI/GSC detection
  15. MAXI GRB220310.02: Global MASTER-Net observations report
  16. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  17. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  18. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  19. GRB 211227A: MAXI/GSC detection
  20. GRB 211225A: MITSuME Akeno optical upper limits
  21. MAXI GRB211225.14: Global MASTER-Net observations report
  22. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  23. GRB 211218A: MITSuME Akeno optical upper limits
  24. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  25. MAXI GRB211218.04: Global MASTER-Net observations report
  26. Fermi GRB 211211B: Global MASTER-Net observations report
  27. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  28. GRB 211115A: MAXI/GSC detection
  29. GRB 210822A: Swift/UVOT Detection
  30. MAXI GRB210709.93: Global MASTER-Net observations report
  31. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  32. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  33. MAXI GRB210607.82: Global MASTER-Net observations report
  34. Konus-Wind detection of GRB 210602A
  35. MAXI GRB210602.50: Global MASTER-Net observations report
  36. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  37. GRB 210602A: MAXI/GSC detection
  38. GRB 210528B: DDOTI Upper Limits on the Afterglow
  39. MAXI GRB210528.95: Global MASTER-Net observations report
  40. GRB 210528B: MAXI/GSC detection
  41. MAXI GRB210521.54: Global MASTER-Net observations report
  42. GRB 210521A: MAXI/GSC detection
  43. Swift Detection of MAXI J1803-298 including an optical counterpart
  44. MAXI GRB210501.83: Global MASTER-Net observations report
  45. MAXI GRB210320.89: Global MASTER-Net observations report
  46. GRB 210320A: MAXI/GSC detection
  47. GRB 210305A: Swift/UVOT Upper Limits
  48. Konus-Wind detection of GRB 210222A
  49. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 210222A: MAXI/GSC detection
  51. GRB 210210A: Swift/UVOT Detection
  52. SGR 1935+2154: MAXI/GSC detection
  53. NuEm-210111A: MAXI/GSC upper limit
  54. MAXI GRB210110.64: Global MASTER-Net observations report
  55. GRB 210110A: MAXI/GSC detection
  56. GRB 210109A: MAXI/GSC detection
  57. GRB 210102B: further Swift-XRT observations
  58. GRB 210102B: Assy optical afterglow identification
  59. GRB 210102B: Tiled Swift observations
  60. GRB 210102B: Assy optical observations
  61. GRB 210102B: Swift-XRT observations
  62. MAXI GRB210102.38: Global MASTER-Net observations report
  63. GRB 210102B: Tiled Swift observations
  64. GRB 210102B: MAXI/GSC detection
  65. IceCube-201209A : MAXI/GSC upper limit
  66. MAXI GRB201021.68: Global MASTER-Net observations report
  67. GRB 201021B MAXI/GSC detection
  68. GRB 200903D: MAXI/GSC detection
  69. GRB 200809B: Fermi GBM detection
  70. GRB 200809B: Swift-XRT afterglow detection
  71. GRB 200809B: MAXI/GSC detection
  72. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  73. GRB 200615B: MAXI/GSC detection
  74. Fermi GRB 200524A: Global MASTER-Net observations report
  75. GRB 200517A: Swift-XRT Confirmation of afterglow
  76. Fermi GBM Sub-Threshold Detection of GRB 200517A
  77. GRB 200517A: Swift-XRT afterglow detection
  78. GRB 200514A: AstroSat CZTI detection
  79. GRB 200517A: Tiled Swift observations
  80. GRB 200517A: MAXI/GSC detection
  81. GRB 200514A: MITSuME Akeno optical upper limits
  82. GRB 200514A: CALET Gamma-Ray Burst Monitor detection
  83. GRB 200514A: MAXI/GSC detection
  84. Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
  85. SGR 1935+2154: MAXI/GSC detection
  86. GRB 200320B: MAXI/GSC detection
  87. LIGO/Virgo S200316bj: Coverage and upper limits from MAXI/GSC observations
  88. LIGO/Virgo S200311bg: Coverage and upper limits from MAXI/GSC observations
  89. GRB 200310A: MAXI/GSC detection
  90. LIGO/Virgo S200302c: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
  92. LIGO/Virgo S200224ca: Coverage and upper limits from MAXI/GSC observations
  93. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  94. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  95. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  96. GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
  97. GRB 200205A / Swift trigger 954304: VLT optical observations
  98. GRB 200205A: MAXI/GSC detection
  99. MAXI GRB200205.29: Global MASTER-Net observations report
  100. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations

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