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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

21117 results found.

  1. IceCube Alert 200728.35: Global MASTER-Net observations report
  2. Baksan Neutrino Observatory Alert 200726.66: Global MASTER-Net observations report
  3. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  4. GRB 200723A: Swift ToO observations
  5. GRB 200723A: GOTO candidate afterglow and host galaxy
  6. Fermi GRB 200723A: Global MASTER-Net observations report
  7. GRB 200716C: Kitab optical observations
  8. GRB 200716C: CrAO, Terskol, Assy-Turgen optical observations
  9. GRB 200714E: Swift-XRT afterglow detection
  10. Fermi GRB 200718A: Global MASTER-Net observations report
  11. GRB 200716C: Optical observations from HCT
  12. Fermi GRB 200716A: Global MASTER-Net observations report
  13. GRB 200522A: HST NIR counterpart confirmation
  14. Swift GRB200716.96: Global MASTER-Net observations report
  15. Fermi GRB 200716B: Global MASTER-Net observations report
  16. GRB 200715A: Swift-XRT afterglow detection
  17. GRB 200715A: Swift ToO observations
  18. GRB 200714E: Swift-XRT observations
  19. Fermi GRB 200714E: Global MASTER-Net observations report
  20. GRB 200714E: Swift ToO observations
  21. GRB 200714E: Swift/BAT-GUANO detection and arcminute localization
  22. Fermi GRB 200714D: Global MASTER-Net observations report
  23. Fermi GRB 200714A: Global MASTER-Net observations report
  24. GRB 200522A: Candidate Optical/nIR Counterpart from Gemini and HST Imaging
  25. Fermi trigger No 616370565: Global MASTER-Net observations report
  26. GRB 200711A: Swift/UVOT Upper Limits
  27. GRB 200711A: KAIT Optical Upper Limit
  28. Swift GRB 200711A: Global MASTER-Net observations report
  29. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  30. GRB 200709B: Swift-XRT observations
  31. GRB 200709B: Tiled Swift observations
  32. Fermi trigger No 615741133: Global MASTER-Net observations report
  33. Fermi GRB 200705A: Global MASTER-Net observations report
  34. Fermi GRB 200702A: Global MASTER-Net observations report
  35. GRB 200630A: Swift/UVOT Upper Limits
  36. GRB 200623A: Swift XRT further observations
  37. Fermi trigger No 615174580: Global MASTER-Net observations report
  38. Fermi GRB 200629A: Global MASTER-Net observations report
  39. GRB 200522A: Gemini North spectroscopy of the putative host galaxy
  40. GRB 200623A: Further MMTCam Observations of XRT Source #3
  41. GRB 200623A: LBT optical observations
  42. GRB 200623A : SMA observations at Swift/XRT Source #3
  43. Fermi GRB 200626A: Global MASTER-Net observations report
  44. GRB 200625A: Swift ToO observations
  45. Fermi GRB 200625A: Global MASTER-Net observations report
  46. Updated catalog of X-ray bursts of SGR J1935+2154 from Insight-HXMT observations
  47. GRB 200623A: MMT observations at XRT Source #3
  48. GRB 200623A: Swift/UVOT Upper Limits
  49. GRB 200623A: Swift-XRT observations
  50. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  51. GRB 200623A: TNG optical observations
  52. Fermi GRB 200623B: Global MASTER-Net observations report
  53. GRB 200623A: Swift ToO observations
  54. GRB 200623A: Swift/BAT-GUANO detection and arcminute localization of a short GRB
  55. Fermi GRB 200623A: Global MASTER-Net observations report
  56. IceCube-200620A: INTEGRAL was inactive at the time of the event
  57. IceCube-200620A: MASTER previous detection of ZTF20abgvabi/AT2020ncr
  58. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  59. Fermi-LAT Gamma-ray Observations of IceCube-200620A
  60. GRB 200613A: Continued CrAO optical observations
  61. IceCube Alert 200620.13: Global MASTER-Net observations report
  62. GRB 200613A: CrAO optical observations
  63. GRB 200613A: R-band observations from HCT
  64. GRB 200613A: Further Liverpool Telescope observations
  65. Fermi GRB 200619B: Global MASTER-Net observations report
  66. Fermi trigger No 614239407: Global MASTER-Net observations report
  67. Fermi trigger No 614226976: Global MASTER-Net observations report
  68. GRB 200613A: continued Kitab optical observations
  69. GRB 200613A: SAO RAS optical observations
  70. Swift/UVOT Observations of IceCube 200615A
  71. GRB 200613A: Mondy optical observations
  72. Fermi trigger No 614103490: Global MASTER-Net observations report
  73. Baksan Neutrino Observatory Alert 200617.47: Global MASTER-Net observations report
  74. Swift-XRT observations of IceCube 200615A
  75. GRB 200613A: Jet-break from Xinglong-2.16m optical observations
  76. Fermi-LAT Gamma-ray Observations of IceCube-200615A
  77. Fermi-LAT Gamma-ray Observations of IceCube-200614A and detection of a new gamma-ray source, Fermi J0202.8+3132
  78. Fermi GRB 200616A: Global MASTER-Net observations report
  79. GRB 200613A: continued AbAO optical afterglow observations
  80. IceCube-200615A: Upper limits from Fermi-GBM Observations
  81. IceCube Alert 200615.62: Global MASTER-Net observations report
  82. GRB 200613A: Continued Xinglong-2.16m optical observations
  83. Fermi GRB 200615A: Global MASTER-Net observations report
  84. Baksan Neutrino Observatory Alert 200614.34: Global MASTER-Net observations report
  85. IceCube Alert 200614.53: Global MASTER-Net observations report
  86. GRB 200613A: Swift/UVOT Detection
  87. GRB 200613A: Xinglong-2.16m optical observations
  88. Fermi GRB 200614A: Global MASTER-Net observations report
  89. GRB 200613A: Liverpool Telescope observations
  90. GRB 200613A: Kitab and AbAO optical afterglow observations, host galaxy candidate
  91. GRB 200613A: Swift-XRT afterglow detection
  92. GRB 200613A: Candidate afterglow from OAJ
  93. Fermi GRB 200613A: Global MASTER-Net observations report
  94. GRB 200613A: Swift ToO observations
  95. GRB 200613A: Fermi-LAT detection
  96. GRB 200612A: Swift/UVOT Upper Limits
  97. Baksan Neutrino Observatory Alert 200611.74: Global MASTER-Net observations report
  98. Fermi trigger No 613630183: Global MASTER-Net observations report
  99. Swift GRB200612.19: Global MASTER-Net observations report
  100. Swift GRB 200608A: Global MASTER-Net observations report

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