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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"

4738 results found.

  1. GRB 210708B: Swift detection of a possible burst
  2. Fermi GBM Observations of SGR J1935+2154
  3. GRB 210704A: Fermi-LAT detection
  4. Fermi trigger No 647108723: Global MASTER-Net observations report
  5. Fermi trigger No 647120009: Global MASTER-Net observations report
  6. GRB 210702A: iTelescope optical afterglow observations
  7. Fermi GRB 210627B: Global MASTER-Net observations report
  8. Fermi GRB 210627A: Global MASTER-Net observations report
  9. Fermi trigger No 646322348: Global MASTER-Net observations report
  10. Fermi GRB 210626A: Global MASTER-Net observations report
  11. Fermi trigger No 646189108: Global MASTER-Net observations report
  12. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  13. Swift Trigger 1057131: detection of a burst from SGR Swift J1555.2-5402
  14. GRB 210619B: SAO RAS optical observations
  15. GRB 210621A: Fermi GBM Final Real-time Localization
  16. GRB 210619B: CAHA 2.2m photometric monitoring
  17. GRB 210619B: Liverpool Telescope r'-band observations
  18. GRB 210619B: Liverpool telescope imaging of a red afterglow
  19. Fermi trigger No 645857659: Global MASTER-Net observations report
  20. Swift GRB210619.99: Global MASTER-Net OT detection
  21. GRB 210618A: DDOTI upper limit for the optical afterglow
  22. GRB 210323B: Fermi GBM observation
  23. Fermi GRB 210615A: Global MASTER-Net observations report
  24. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  25. GRB 210610A: Fermi GBM observations
  26. GRB 210610B: iTelescope optical afterglow observations
  27. GRB 210610B: Further SAO RAS optical observations
  28. GRB 210610A: SAO RAS optical observations
  29. GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
  30. GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
  31. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  32. GRB 210606A: Fermi GBM detection
  33. Konus-Wind detection of GRB 210610A
  34. GRB 210610B: SAO RAS optical observations
  35. Fermi trigger No 645047470: Global MASTER-Net observations report
  36. GRB 210610A: Swift detection of a burst with an optical counterpart
  37. Fermi-LAT Gamma-ray Observations of IceCube-210608A
  38. IceCube-210608A: IceCube observation of a high-energy neutrino candidate track-like event
  39. IceCube Alert 210608.15: Global MASTER-Net observations report
  40. Konus-Wind detection of GRB 210602A
  41. GRB 210606B: AGILE detection
  42. GRB 210606A: Swift/BAT-GUANO detection and arcminute localization
  43. GRB 210606A: Fermi GBM Final Real-time Localization
  44. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  45. SGR J1555.2-5402: Swift-BAT refined analysis
  46. Fermi trigger No 644449593: Global MASTER-Net observations report
  47. Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
  48. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  49. Swift Detection of probable new Swift SGR J1555.2-5402
  50. MAXI GRB210602.50: Global MASTER-Net observations report
  51. Swift GRB210603.41: Global MASTER-Net observations report
  52. Fermi trigger No 644359567: Global MASTER-Net observations report
  53. GRB 210602A: MAXI/GSC detection
  54. GRB 210529B: DDOTI Upper Limits on the Afterglow
  55. Fermi GRB 210529B: Global MASTER-Net observations report
  56. GRB 210528A: Fermi GBM detection
  57. GRB 210528A: AstroSat CZTI detection
  58. GRB 210528A: BALROG localization (Fermi Trigger 643903431 / GRB 210528586)
  59. GRB 210528A: Fermi GBM Final Real-time Localization
  60. Fermi GRB 210524B: DDOTI Upper Limits on the Afterglow
  61. Fermi GRB 210519A: Global MASTER-Net observations report
  62. IPN triangulation of GRB 210518A
  63. Fermi trigger No 643065622: Global MASTER-Net observations report
  64. GRB 210518.889: DDOTI Upper Limits on the Afterglow
  65. Fermi trigger No 642991619: Global MASTER-Net observations report
  66. Fermi GRB 210516A: Global MASTER-Net observations report
  67. Fermi GRB 210515B: Global MASTER-Net observations report
  68. Fermi GRB 210515A: Global MASTER-Net observations report
  69. Fermi GRB 210511A: Global MASTER-Net observations report
  70. Fermi GRB 210510A: DDOTI Upper Limits on the Afterglow
  71. Fermi GRB 210510A: Global MASTER-Net observations report
  72. Swift trigger 1047857 is 4U 1700-377
  73. Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
  74. IceCube-210503A: IceCube observation of a high-energy neutrino candidate event
  75. DDOTI Observations of ZTF21aayokph (AT2021lfa)
  76. Swift GRB210504.58: Global MASTER-Net observations report
  77. Fermi GRB 210503A: Global MASTER-Net observations report
  78. Swift GRB210502.74: Global MASTER-Net observations report
  79. Swift Detection of MAXI J1803-298 including an optical counterpart
  80. Fermi GRB 210501A: Global MASTER-Net observations report
  81. GRB 210430A: Swift detection of a burst
  82. Swift Trigger 1045571 is not a GRB
  83. Fermi GRB 210427A: Global MASTER-Net observations report
  84. GRB 210424.694: DDOTI Upper Limits on the Afterglow
  85. GRB 210420B: follow-up photometry of optical afterglow at INASAN/Simeiz
  86. GRB 210421A: Swift/UVOT Upper Limits
  87. GRB 210421A: DDOTI Upper Limit
  88. GRB 210421A: Swift detection of a burst
  89. Swift GRB210419.98: Global MASTER-Net observations report
  90. IceCube Alert 210416.09: Global MASTER-Net observations report
  91. Fermi GRB 210411A: Global MASTER-Net observations report
  92. GRB 210411A: Fermi GBM Final Real-time Localization
  93. Fermi GRB 210410A: Global MASTER-Net observations report
  94. GRB 210402A: MASTER prompt and follow up optical observation
  95. Fermi trigger No 639199407: Global MASTER-Net observations report
  96. GRB 210402A: LBT observations
  97. GRB 210402A: DDOTI Upper Limits
  98. Swift GRB210403.35: Global MASTER-Net observations report
  99. GRB 210330A: AstroSat CZTI detection
  100. GRB 210328A: AstroSat CZTI detection

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