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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"

913 results found.

  1. GRB 221009A BOOTES-2/TELMA and OSN optical detections
  2. GRB 221008A: Swift-XRT observations
  3. GRB 221008A: Tiled Swift observations
  4. GRB 221008A: MAXI/GSC detection
  5. GRB 221006A: Swift-XRT observations
  6. GRB 221006A: Tiled Swift observations
  7. GRB 221006A: MAXI/GSC detection
  8. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  9. MAXI GRB220706.73: Global MASTER-Net observations report
  10. Trigger 1113743: Swift detection of MAXI J0655-013
  11. GRB 220624A: Fermi GBM Detection
  12. Swift Detection of MAXI J0655-013
  13. MAXI GRB220607.31: Global MASTER-Net observations report
  14. MAXI GRB220607.41: Global MASTER-Net observations report
  15. Konus-Wind detection of GRB 220506A
  16. Konus-Wind detection of GRB 220514B
  17. GRB 220514B: Swift-XRT observations
  18. GRB 220514B: Tiled Swift observations
  19. GRB 220514B: MAXI/GSC detection
  20. MAXI GRB220514.98: Global MASTER-Net observations report
  21. GRB 220506A: MITSuME Akeno optical upper limits
  22. GRB 220506A: GIT optical upper limit.
  23. GRB 220506A: BOOTES-5/JGT optical upper limit
  24. GRB 220506A: Swift-XRT afterglow detection
  25. GRB 220506A: Tiled Swift observations
  26. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  27. MAXI GRB220506.27: Global MASTER-Net observations report
  28. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  29. GRB 220310A: MITSuME Akeno optical observation
  30. IPN triangulation of GRB 220310A
  31. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  32. Konus-Wind detection of GRB 220310A
  33. GRB 220310A: GIT confirmation of optical afterglow.
  34. GRB 220310A: MASTER optical counterpart detection
  35. GRB 220310A: Swift ToO observations
  36. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  37. GRB 220310A: MAXI/GSC detection
  38. MAXI GRB220310.02: Global MASTER-Net observations report
  39. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  40. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  41. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  42. GRB 211227A: MAXI/GSC detection
  43. GRB 211225A: MITSuME Akeno optical upper limits
  44. MAXI GRB211225.14: Global MASTER-Net observations report
  45. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  46. GRB 211218A: MITSuME Akeno optical upper limits
  47. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  48. MAXI GRB211218.04: Global MASTER-Net observations report
  49. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 211115A: MAXI/GSC detection
  51. Fermi GRB 210812A: Global MASTER-Net observations report
  52. MAXI GRB210709.93: Global MASTER-Net observations report
  53. GRB 210704A: AstroSat CZTI detection
  54. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  55. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  56. MAXI GRB210607.82: Global MASTER-Net observations report
  57. Konus-Wind detection of GRB 210602A
  58. MAXI GRB210602.50: Global MASTER-Net observations report
  59. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  60. GRB 210602A: MAXI/GSC detection
  61. GRB 210528B: DDOTI Upper Limits on the Afterglow
  62. MAXI GRB210528.95: Global MASTER-Net observations report
  63. GRB 210528B: MAXI/GSC detection
  64. MAXI GRB210521.54: Global MASTER-Net observations report
  65. GRB 210521A: MAXI/GSC detection
  66. Swift Detection of MAXI J1803-298 including an optical counterpart
  67. MAXI GRB210501.83: Global MASTER-Net observations report
  68. MAXI GRB210320.89: Global MASTER-Net observations report
  69. GRB 210320A: MAXI/GSC detection
  70. Konus-Wind detection of GRB 210222A
  71. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  72. GRB 210222A: MAXI/GSC detection
  73. SGR 1935+2154: MAXI/GSC detection
  74. NuEm-210111A: MAXI/GSC upper limit
  75. MAXI GRB210110.64: Global MASTER-Net observations report
  76. GRB 210110A: MAXI/GSC detection
  77. GRB 210109A: MAXI/GSC detection
  78. GRB 210102B: further Swift-XRT observations
  79. GRB 210102B: Assy optical afterglow identification
  80. GRB 210102B: Tiled Swift observations
  81. GRB 210102B: Assy optical observations
  82. GRB 210102B: Swift-XRT observations
  83. MAXI GRB210102.38: Global MASTER-Net observations report
  84. GRB 210102B: Tiled Swift observations
  85. GRB 210102B: MAXI/GSC detection
  86. IceCube-201209A : MAXI/GSC upper limit
  87. IceCube Alert 201130.85: Global MASTER-Net observations report
  88. MAXI GRB201021.68: Global MASTER-Net observations report
  89. GRB 201021B MAXI/GSC detection
  90. Swift GRB 201017A: Global MASTER-Net observations report
  91. GRB 201014A: BOOTES-1 and -2 early optical upper limits
  92. Fermi GRB 200916A: Global MASTER-Net observations report
  93. GRB 200903D: MAXI/GSC detection
  94. GRB 200809B: Fermi GBM detection
  95. GRB 200809B: Swift-XRT afterglow detection
  96. GRB 200809B: MAXI/GSC detection
  97. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  98. GRB 200615B: MAXI/GSC detection
  99. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  100. GRB 200517A: Swift-XRT Confirmation of afterglow

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