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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"

5038 results found.

  1. GRB 201128A: Swift-XRT refined Analysis
  2. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  3. IceCube Alert 201124.34: Global MASTER-Net observations report
  4. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  5. GRB 201015A radio afterglow with e-MERLIN
  6. Fermi GRB 201120B: Global MASTER-Net observations report
  7. Baksan Neutrino Observatory Alert 201120.43: Global MASTER-Net observations report
  8. ZTF20acozryr/AT2020yxz (GRB 201103B): correction to the GCN #28883 CrAO/ZTSh optical observations
  9. GRB 201116A: OSN Afterglow Candidate
  10. Fermi trigger No 627198169: Global MASTER-Net observations report
  11. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  12. ZTF20acozryr/AT2020yxz (GRB 201103B): CrAO/ZTSh optical observations
  13. Fermi GRB 201111A: Global MASTER-Net observations report
  14. Fermi GRB 201104A: Global MASTER-Net observations report
  15. Fermi GRB 201031B: Global MASTER-Net observations report
  16. GRB 201031B: BALROG localization (Fermi Trigger 625859489 / GRB 201031744)
  17. GRB 201031B: Fermi GBM Final Real-time Localization
  18. GRB 201029A: Swift-XRT refined Analysis
  19. Fermi trigger No 625695596: Global MASTER-Net observations report
  20. GRB 201027A: Swift-XRT refined Analysis
  21. GRB 201026A: Swift-XRT refined Analysis
  22. GRB 201020A: 1.3m DFOT, optical upper limits
  23. GRB 201024A: 1.3m DFOT optical observations
  24. GRB 201020B: 1.3m DFOT continued optical follow-up observations
  25. GRB 201024A: MITSuME Akeno optical upper limits
  26. GRB 201024A: Swift-XRT refined Analysis
  27. GRB 201024A: VIRT optical observations
  28. GRB 201020B: Redshift from GTC/OSIRIS
  29. GRB 201024A: Redshift from GTC/OSIRIS
  30. GRB 201024A: BOOTES-2/TELMA early optical observation and 1.5m OSN follow-up
  31. GRB 201024A: MASTER correction to GCN 28760
  32. Swift GRB201024A: Global MASTER-Net OT detection
  33. Swift GRB201024.12: Global MASTER-Net observations report
  34. GRB 201021C: Swift-XRT refined Analysis
  35. GRB 201020A: Swift/UVOT Observations
  36. GRB 201020A: Swift-XRT refined Analysis
  37. GRB 201020A: Swift detection of a burst with an optical counterpart.
  38. GRB 201017A: SAO RAS optical observations
  39. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  40. GRB 201017A: Swift-XRT refined Analysis
  41. GRB 201015A: MMT afterglow imaging
  42. GRB 201015A: Assy and Mondy optical observations
  43. GRB 201015A: Swift-XRT refined Analysis
  44. GRB 201015A: Enhanced Swift-XRT position
  45. GRB 201015A: GOTO confirmation of afterglow detection
  46. GRB 201015A: NOT optical afterglow confirmation
  47. GRB 201015A: Swift-XRT observations
  48. IceCube Alert 201014.09: Global MASTER-Net observations report
  49. GRB 201013A: Swift-XRT refined Analysis
  50. SGR 1830-0645: pre-discovery detection in Swift/BAT
  51. Fermi trigger No 624121589: Global MASTER-Net observations report
  52. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  53. Fermi trigger No 623846261: Global MASTER-Net observations report
  54. GRB 201006A: Swift-XRT refined Analysis
  55. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  56. IceCube-200926A: No significant detection in HAWC
  57. Fermi GRB 200929A: Global MASTER-Net observations report
  58. GRB 200928A: Fermi GBM Final Localization
  59. IceCube Alert 200926.94: Global MASTER-Net observations report
  60. Fermi GRB 200925A: Global MASTER-Net observations report
  61. Fermi GRB 200924A: Global MASTER-Net observations report
  62. GRB 200924B: Fermi GBM Final Localization
  63. Fermi trigger No 622618714: Global MASTER-Net observations report
  64. GRB 200924A: Fermi GBM Final Real-time Localization
  65. Fermi GRB 200923A: Global MASTER-Net observations report
  66. IceCube Alert 200921.80: Global MASTER-Net observations report
  67. Swift GRB 200922A: Global MASTER-Net observations report
  68. GRB 200922A: Swift-XRT refined Analysis
  69. GRB 200922B: Fermi GBM Final Real-time Localization
  70. Fermi GRB 200919C: Global MASTER-Net observations report
  71. GRB 200917A: Swift-XRT refined Analysis
  72. IPN triangulation of GRB 200916B (short)
  73. IceCube Alert 200914.00: Global MASTER-Net observations report
  74. IPN triangulation of GRB 200907A (short)
  75. Fermi GRB 200909A: Global MASTER-Net observations report
  76. GRB 200907B: AstroSat CZTI detection
  77. GRB 200907B: Swift-XRT refined Analysis
  78. Fermi GRB 200907C: Global MASTER-Net observations report
  79. GRB 200907C: Fermi GBM Final Real-time Localization
  80. GRB 200907A: AGILE/MCAL detection of a burst
  81. GRB 200906A: Swift-XRT refined Analysis
  82. Fermi GRB 200903B: Global MASTER-Net observations report
  83. GRB 200901B: Swift-XRT refined Analysis
  84. GRB 200901A: Swift-XRT refined Analysis
  85. GRB 200829A: Continued Nanshan/NEXT optical observations
  86. Fermi GRB 200830A: Global MASTER-Net observations report
  87. Konus-Wind detection of GRB 200829A (a clone of GRB 200826B?)
  88. GRB 200829A: Swift-XRT refined Analysis
  89. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  90. Fermi GRB 200826B: Global MASTER-Net observations report
  91. Fermi GRB 200824A: Global MASTER-Net observations report
  92. Fermi GRB 200826A: Global MASTER-Net observations report
  93. GRB 200824A: Fermi GBM Final Real-time Localization
  94. GRB 200819A: Swift-XRT refined Analysis
  95. Fermi trigger No 619270776: Global MASTER-Net observations report
  96. GRB 200809B: Swift-XRT afterglow detection
  97. GRB 200806A: Swift-XRT refined Analysis
  98. GRB 200803A: Swift-XRT afterglow detection
  99. LAT GRB200803.15: Global MASTER-Net observations report
  100. Fermi GRB 200803A: Global MASTER-Net observations report

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