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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"

1006 results found.

  1. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  2. MAXI GRB220706.73: Global MASTER-Net observations report
  3. Trigger 1113743: Swift detection of MAXI J0655-013
  4. GRB 220624A: Fermi GBM Detection
  5. Swift Detection of MAXI J0655-013
  6. MAXI GRB220607.31: Global MASTER-Net observations report
  7. MAXI GRB220607.41: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 220506A
  9. Konus-Wind detection of GRB 220514B
  10. GRB 220514B: Swift-XRT observations
  11. GRB 220514B: Tiled Swift observations
  12. GRB 220514B: MAXI/GSC detection
  13. MAXI GRB220514.98: Global MASTER-Net observations report
  14. GRB 220506A: MITSuME Akeno optical upper limits
  15. GRB 220506A: GIT optical upper limit.
  16. GRB 220506A: BOOTES-5/JGT optical upper limit
  17. GRB 220506A: Swift-XRT afterglow detection
  18. GRB 220506A: Tiled Swift observations
  19. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  20. MAXI GRB220506.27: Global MASTER-Net observations report
  21. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  22. GRB 220310A: MITSuME Akeno optical observation
  23. IPN triangulation of GRB 220310A
  24. GRB 220310A: [KAO-Egypt] SDSS r, i observation
  25. Konus-Wind detection of GRB 220310A
  26. GRB 220310A: GIT confirmation of optical afterglow.
  27. GRB 220310A: MASTER optical counterpart detection
  28. GRB 220310A: Swift ToO observations
  29. GRB 220310A: CALET Gamma-Ray Burst Monitor detection
  30. GRB 220310A: MAXI/GSC detection
  31. MAXI GRB220310.02: Global MASTER-Net observations report
  32. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  33. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  34. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  35. GRB 211227A: MAXI/GSC detection
  36. GRB 211225A: MITSuME Akeno optical upper limits
  37. MAXI GRB211225.14: Global MASTER-Net observations report
  38. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  39. GRB 211218A: MITSuME Akeno optical upper limits
  40. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  41. MAXI GRB211218.04: Global MASTER-Net observations report
  42. GRB 211115A: CALET Gamma-Ray Burst Monitor detection
  43. GRB 211115A: MAXI/GSC detection
  44. Fermi GRB 210812A: Global MASTER-Net observations report
  45. MAXI GRB210709.93: Global MASTER-Net observations report
  46. GRB 210704A: AstroSat CZTI detection
  47. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  48. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  49. MAXI GRB210607.82: Global MASTER-Net observations report
  50. Konus-Wind detection of GRB 210602A
  51. MAXI GRB210602.50: Global MASTER-Net observations report
  52. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  53. GRB 210602A: MAXI/GSC detection
  54. GRB 210528B: DDOTI Upper Limits on the Afterglow
  55. MAXI GRB210528.95: Global MASTER-Net observations report
  56. GRB 210528B: MAXI/GSC detection
  57. MAXI GRB210521.54: Global MASTER-Net observations report
  58. GRB 210521A: MAXI/GSC detection
  59. Swift Detection of MAXI J1803-298 including an optical counterpart
  60. MAXI GRB210501.83: Global MASTER-Net observations report
  61. MAXI GRB210320.89: Global MASTER-Net observations report
  62. GRB 210320A: MAXI/GSC detection
  63. Konus-Wind detection of GRB 210222A
  64. GRB 210222A: CALET Gamma-Ray Burst Monitor detection
  65. GRB 210222A: MAXI/GSC detection
  66. SGR 1935+2154: MAXI/GSC detection
  67. NuEm-210111A: MAXI/GSC upper limit
  68. MAXI GRB210110.64: Global MASTER-Net observations report
  69. GRB 210110A: MAXI/GSC detection
  70. GRB 210109A: MAXI/GSC detection
  71. GRB 210102B: further Swift-XRT observations
  72. GRB 210102B: Assy optical afterglow identification
  73. GRB 210102B: Tiled Swift observations
  74. GRB 210102B: Assy optical observations
  75. GRB 210102B: Swift-XRT observations
  76. MAXI GRB210102.38: Global MASTER-Net observations report
  77. GRB 210102B: Tiled Swift observations
  78. GRB 210102B: MAXI/GSC detection
  79. IceCube-201209A : MAXI/GSC upper limit
  80. IceCube Alert 201130.85: Global MASTER-Net observations report
  81. MAXI GRB201021.68: Global MASTER-Net observations report
  82. GRB 201021B MAXI/GSC detection
  83. Swift GRB 201017A: Global MASTER-Net observations report
  84. GRB 201014A: BOOTES-1 and -2 early optical upper limits
  85. Fermi GRB 200916A: Global MASTER-Net observations report
  86. GRB 200903D: MAXI/GSC detection
  87. GRB 200809B: Fermi GBM detection
  88. GRB 200809B: Swift-XRT afterglow detection
  89. GRB 200809B: MAXI/GSC detection
  90. GRB 200615B: CALET Gamma-Ray Burst Monitor detection
  91. GRB 200615B: MAXI/GSC detection
  92. IceCube-200615A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  93. GRB 200517A: Swift-XRT Confirmation of afterglow
  94. Fermi GBM Sub-Threshold Detection of GRB 200517A
  95. GRB 200517A: Swift-XRT afterglow detection
  96. GRB 200514A: AstroSat CZTI detection
  97. GRB 200517A: Tiled Swift observations
  98. GRB 200517A: MAXI/GSC detection
  99. GRB 200514A: MITSuME Akeno optical upper limits
  100. GRB 200514A: CALET Gamma-Ray Burst Monitor detection

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