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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"

5158 results found.

  1. GRB 201221D: candidate optical counterpart from the NOT
  2. GRB 201221A: Swift-BAT refined analysis
  3. GRB 201221D: Prompt enhanced Swift-XRT position
  4. GRB 201221A: Swift-XRT refined Analysis
  5. Swift Trigger 1014012: possible GRB 201221C
  6. GRB 201221A: Enhanced Swift-XRT position
  7. GRB 201221A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 5.7
  8. GRB 201221A: Prompt enhanced Swift-XRT position
  9. GRB 201221A: Swift detection of a burst
  10. Konus-Wind observation of GRB 201218A
  11. Fermi GRB 201218B: Global MASTER-Net observations report
  12. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  13. Fermi GRB 201216A: Global MASTER-Net observations report
  14. GRB 201208A: Fermi GBM observation
  15. GRB 201207A: AstroSat CZTI detection
  16. Fermi GRB 201208A: Global MASTER-Net observations report
  17. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  18. GRB 201203A: Swift-XRT afterglow detection
  19. IceCube Alert 201130.85: Global MASTER-Net observations report
  20. Baksan Neutrino Observatory Alert 201128.90: Global MASTER-Net observations report
  21. GRB 201128A: Swift-XRT refined Analysis
  22. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  23. IceCube Alert 201124.34: Global MASTER-Net observations report
  24. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  25. GRB 201015A radio afterglow with e-MERLIN
  26. Fermi GRB 201120B: Global MASTER-Net observations report
  27. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  28. ZTF20acozryr/AT2020yxz (GRB 201103B): correction to the GCN #28883 CrAO/ZTSh optical observations
  29. GRB 201116A: OSN Afterglow Candidate
  30. Fermi trigger No 627198169: Global MASTER-Net observations report
  31. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  32. ZTF20acozryr/AT2020yxz (GRB 201103B): CrAO/ZTSh optical observations
  33. Fermi GRB 201111A: Global MASTER-Net observations report
  34. Fermi GRB 201104A: Global MASTER-Net observations report
  35. Fermi GRB 201031B: Global MASTER-Net observations report
  36. GRB 201031B: BALROG localization (Fermi Trigger 625859489 / GRB 201031744)
  37. GRB 201031B: Fermi GBM Final Real-time Localization
  38. GRB 201029A: Swift-XRT refined Analysis
  39. Fermi trigger No 625695596: Global MASTER-Net observations report
  40. GRB 201027A: Swift-XRT refined Analysis
  41. GRB 201026A: Swift-XRT refined Analysis
  42. GRB 201020A: 1.3m DFOT, optical upper limits
  43. GRB 201024A: 1.3m DFOT optical observations
  44. GRB 201020B: 1.3m DFOT continued optical follow-up observations
  45. GRB 201024A: MITSuME Akeno optical upper limits
  46. GRB 201024A: Swift-XRT refined Analysis
  47. GRB 201024A: VIRT optical observations
  48. GRB 201020B: Redshift from GTC/OSIRIS
  49. GRB 201024A: Redshift from GTC/OSIRIS
  50. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  51. GRB 201024A: MASTER correction to GCN 28760
  52. Swift GRB201024A: Global MASTER-Net OT detection
  53. Swift GRB201024.12: Global MASTER-Net observations report
  54. GRB 201021C: Swift-XRT refined Analysis
  55. GRB 201020A: Swift/UVOT Observations
  56. GRB 201020A: Swift-XRT refined Analysis
  57. GRB 201020A: Swift detection of a burst with an optical counterpart.
  58. GRB 201017A: SAO RAS optical observations
  59. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  60. GRB 201017A: Swift-XRT refined Analysis
  61. GRB 201015A: MMT afterglow imaging
  62. GRB 201015A: Assy and Mondy optical observations
  63. GRB 201015A: Swift-XRT refined Analysis
  64. GRB 201015A: Enhanced Swift-XRT position
  65. GRB 201015A: GOTO confirmation of afterglow detection
  66. GRB 201015A: NOT optical afterglow confirmation
  67. GRB 201015A: Swift-XRT observations
  68. IceCube Alert 201014.09: Global MASTER-Net observations report
  69. GRB 201013A: Swift-XRT refined Analysis
  70. SGR 1830-0645: pre-discovery detection in Swift/BAT
  71. Fermi trigger No 624121589: Global MASTER-Net observations report
  72. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  73. Fermi trigger No 623846261: Global MASTER-Net observations report
  74. GRB 201006A: Swift-XRT refined Analysis
  75. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  76. IceCube-200926A: No significant detection in HAWC
  77. Fermi GRB 200929A: Global MASTER-Net observations report
  78. GRB 200928A: Fermi GBM Final Localization
  79. IceCube Alert 200926.94: Global MASTER-Net observations report
  80. Fermi GRB 200925A: Global MASTER-Net observations report
  81. Fermi GRB 200924A: Global MASTER-Net observations report
  82. GRB 200924B: Fermi GBM Final Localization
  83. Fermi trigger No 622618714: Global MASTER-Net observations report
  84. GRB 200924A: Fermi GBM Final Real-time Localization
  85. Fermi GRB 200923A: Global MASTER-Net observations report
  86. IceCube Alert 200921.80: Global MASTER-Net observations report
  87. Swift GRB 200922A: Global MASTER-Net observations report
  88. GRB 200922A: Swift-XRT refined Analysis
  89. GRB 200922B: Fermi GBM Final Real-time Localization
  90. Fermi GRB 200919C: Global MASTER-Net observations report
  91. GRB 200917A: Swift-XRT refined Analysis
  92. IPN triangulation of GRB 200916B (short)
  93. IceCube Alert 200914.00: Global MASTER-Net observations report
  94. IPN triangulation of GRB 200907A (short)
  95. Fermi GRB 200909A: Global MASTER-Net observations report
  96. GRB 200907B: AstroSat CZTI detection
  97. GRB 200907B: Swift-XRT refined Analysis
  98. Fermi GRB 200907C: Global MASTER-Net observations report
  99. GRB 200907C: Fermi GBM Final Real-time Localization
  100. GRB 200907A: AGILE/MCAL detection of a burst

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