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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"

5401 results found.

  1. Fermi GBM observation of another bright burst in the direction of SGR 1935+2154
  2. Fermi trigger No 653066776: Global MASTER-Net observations report
  3. Fermi trigger No 653084584: Global MASTER-Net observations report
  4. Fermi trigger No 653083551: Global MASTER-Net observations report
  5. Fermi trigger No 653072474: Global MASTER-Net observations report
  6. Fermi trigger No 653054042: Global MASTER-Net observations report
  7. Fermi trigger No 653049776: Global MASTER-Net observations report
  8. Fermi trigger No 653022153: Global MASTER-Net observations report
  9. Swift detection of a burst from SGR Swift J1555.2-5402
  10. Fermi trigger No 652927551: Global MASTER-Net observations report
  11. Fermi trigger No 652911693: Global MASTER-Net observations report
  12. Fermi trigger No 652906639: Global MASTER-Net observations report
  13. Fermi GRB 210909A: Global MASTER-Net observations report
  14. Fermi GRB 210904A: Global MASTER-Net observations report
  15. Swift GRB210903.59: Global MASTER-Net observations report
  16. Swift GRB210903.58: Global MASTER-Net observations report
  17. Fermi GRB 210903A: Global MASTER-Net observations report
  18. Fermi GRB 210903B: Global MASTER-Net observations report
  19. Integral GRB210829.14: Global MASTER-Net observations report
  20. Fermi GRB 210827A: Global MASTER-Net observations report
  21. GRB 210826A: Swift-XRT observations
  22. Swift detection of an outburst from SGR Swift J1555.2-5402
  23. GRB 210824A: Fermi GBM Observation
  24. GRB 210822A: GROND observations
  25. GRB 210824A: Fermi GBM Final Real-time Localization
  26. GRB 210820A: GROND observations
  27. Fermi GRB 210822B: Global MASTER-Net observations report
  28. Fermi GRB 210821A: Global MASTER-Net observations report
  29. GRB 210820A: LT optical upper limit
  30. GRB 210818A: Swift detection of a burst with an optical counterpart
  31. Swift GRB210807.74: Global MASTER-Net observations report
  32. Fermi GRB 210807C: Global MASTER-Net observations report
  33. GRB 210807A: Swift detection of a burst with an optical counterpart
  34. Fermi trigger No 649814537: Global MASTER-Net observations report
  35. GRB 210802A: MITSuME Okayama optical upper limits
  36. GRB 210802A: DDOTI Upper Limits
  37. GRB 210802A: BOOTES-2/TELMA optical upper limit
  38. GRB 210803A: BALROG localization (Fermi Trigger 649684549 / GRB 210803497)
  39. Fermi trigger No 649627691: Global MASTER-Net observations report
  40. GRB 210731A: Swift-BAT refined analysis
  41. GRB 210731A: Swift-XRT refined Analysis
  42. Fermi trigger No 649519043: Global MASTER-Net observations report
  43. GRB 210731A: MeerLICHT optical afterglow detection
  44. GRB210731A: Enhanced Swift-XRT position
  45. GRB 210731A: Swift detection of a burst
  46. Trigger 1062273: Swift detection of 4U 1700-377
  47. Fermi trigger No 649390368: Global MASTER-Net observations report
  48. Fermi GBM Sub-Threshold Detection of GRB 210726A
  49. Fermi trigger No 649072251: Global MASTER-Net observations report
  50. GRB 210726A: Swift detection of a burst
  51. Fermi trigger No 648959581: Global MASTER-Net observations report
  52. GRB 210725A: Fermi GBM detection
  53. GRB 210725A: CALET Gamma-Ray Burst Monitor detection
  54. Fermi trigger No 648868114: Global MASTER-Net observations report
  55. GRB 210725A: Swift detection of a burst
  56. Swift GRB210725.16: Global MASTER-Net observations report
  57. GRB 210702A: ALMA detection of mm-band rebrightening
  58. Fermi trigger No 648602917: Global MASTER-Net observations report
  59. Fermi trigger No 647942198: Global MASTER-Net observations report
  60. Fermi trigger No 647805873: Global MASTER-Net observations report
  61. Fermi trigger No 647522278: Global MASTER-Net observations report
  62. Fermi GRB 210709A: Global MASTER-Net observations report
  63. GRB 210702A: ALMA detection
  64. GRB 210708B: Swift detection of a possible burst
  65. Fermi GBM Observations of SGR J1935+2154
  66. GRB 210704A: Fermi-LAT detection
  67. Fermi trigger No 647108723: Global MASTER-Net observations report
  68. Fermi trigger No 647120009: Global MASTER-Net observations report
  69. GRB 210702A: iTelescope optical afterglow observations
  70. Fermi GRB 210627B: Global MASTER-Net observations report
  71. Fermi GRB 210627A: Global MASTER-Net observations report
  72. Fermi trigger No 646322348: Global MASTER-Net observations report
  73. Fermi GRB 210626A: Global MASTER-Net observations report
  74. Fermi trigger No 646189108: Global MASTER-Net observations report
  75. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  76. Swift Trigger 1057131: detection of a burst from SGR Swift J1555.2-5402
  77. GRB 210619B: SAO RAS optical observations
  78. GRB 210621A: Fermi GBM Final Real-time Localization
  79. GRB 210619B: CAHA 2.2m photometric monitoring
  80. GRB 210619B: Liverpool Telescope r'-band observations
  81. GRB 210619B: Liverpool telescope imaging of a red afterglow
  82. Fermi trigger No 645857659: Global MASTER-Net observations report
  83. Swift GRB210619.99: Global MASTER-Net OT detection
  84. GRB 210618A: DDOTI upper limit for the optical afterglow
  85. GRB 210323B: Fermi GBM observation
  86. Fermi GRB 210615A: Global MASTER-Net observations report
  87. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  88. GRB 210610A: Fermi GBM observations
  89. GRB 210610B: iTelescope optical afterglow observations
  90. GRB 210610B: Further SAO RAS optical observations
  91. GRB 210610A: SAO RAS optical observations
  92. GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
  93. GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
  94. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  95. GRB 210606A: Fermi GBM detection
  96. Konus-Wind detection of GRB 210610A
  97. GRB 210610B: SAO RAS optical observations
  98. Fermi trigger No 645047470: Global MASTER-Net observations report
  99. GRB 210610A: Swift detection of a burst with an optical counterpart
  100. Fermi-LAT Gamma-ray Observations of IceCube-210608A

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