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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"

6791 results found.

  1. IceCube-210922A: No significant detection in HAWC
  2. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  3. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  4. GRB 210919A: Swift-XRT refined Analysis
  5. GRB 210912A: Swift-XRT refined Analysis
  6. GRB 210826A: further Swift-XRT observations
  7. GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
  8. Konus-Wind detection of GRB 210905A
  9. GRB 210905A: Swift-XRT refined Analysis
  10. GRB 210610A: Maidanak and AbAO optical observations
  11. Swift GRB 210905A: Global MASTER-Net observations report
  12. Swift GRB210903.58: Global MASTER-Net observations report
  13. GRB 210901A: Swift-XRT refined Analysis
  14. GRB 210827A: further Swift-XRT observations
  15. GRB 210827A: Swift-XRT observations
  16. GRB 210826A: Swift-XRT observations
  17. GRB 210826A: Fermi-LAT detection
  18. GRB 210824A: Swift-XRT refined Analysis
  19. Konus-Wind detection of GRB 210822A
  20. GRB 210822A: Swift-XRT refined Analysis
  21. GRB 210822A: Fermi-LAT detection
  22. GRB 210820A: Swift-XRT refined Analysis
  23. GRB 210818A: Swift-XRT refined Analysis
  24. GRB 210712A: Fermi GBM observation
  25. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  26. GRB 210802A: Further Swift/XRT observation and afterglow confirmation
  27. GRB 210807C: Swift-XRT refined Analysis
  28. GRB 210807C: Fermi GBM detection
  29. GRB 210807A: Swift-XRT refined Analysis
  30. GRB 210803A: Fermi GBM observation
  31. GRB 210802A: Swift-XRT afterglow detection
  32. GRB 210802A: Fermi GBM detection
  33. GRB 210802A: Fermi-LAT detection
  34. GRB 210801A: Fermi GBM detection
  35. IceCube-210730A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  36. GRB 210731A: Swift-XRT refined Analysis
  37. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  38. GRB 210726A: Chandra detection of the X-ray afterglow
  39. GRB 210730A: Fermi GBM observation
  40. GRB 210730A: Swift-XRT refined Analysis
  41. GRB 210714A: Fermi GBM observation
  42. GRB 210726A: Swift-XRT refined Analysis
  43. GRB 210725B: Swift-XRT refined Analysis
  44. GRB 210725A: Fermi GBM detection
  45. GRB 210725A: Swift-XRT refined Analysis
  46. GRB 210724A: Swift-XRT refined Analysis
  47. GRB 210723A: Swift-XRT refined Analysis
  48. GRB 210722A: Fermi GBM observation
  49. GRB 210722A: Swift-XRT refined Analysis
  50. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  51. IceCube-210717A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  52. GRB 210704A: Zeiss-1000/SAO-RAS optical observations
  53. Fermi trigger No 647942198: Global MASTER-Net observations report
  54. GRB 210712A: Swift-XRT refined Analysis
  55. GRB 210706A: Swift/XRT afterglow confirmation
  56. GRB 210708A: Swift-XRT refined Analysis
  57. Fermi GBM Observations of SGR J1935+2154
  58. GRB 210706A: Fermi GBM observation
  59. GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
  60. GRB 210704A: OAJ T80 multi-color detections
  61. GRB 210706A: Swift-XRT afterglow detection
  62. Integral GRB210707.02: Global MASTER-Net observations report
  63. GRB 210704A: CAHA 2.2m Afterglow Detection
  64. GRB 210704B: Fermi GBM detection
  65. GRB 210704A: Fermi GBM detection
  66. GRB 210704A: Swift-XRT afterglow detection
  67. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  68. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  69. GRB 210704A: Fermi-LAT detection
  70. GRB 210705A: AGILE/MCAL detection of a burst
  71. Konus-Wind detection of GRB 210702A
  72. GRB 210702A: iTelescope optical afterglow observations
  73. GRB 210702A: Swift-XRT refined Analysis
  74. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  76. GRB 210626A: Swift/XRT afterglow confirmation
  77. GRB 210626A: Fermi GBM observation
  78. GRB 210626A: GIT optical upper limit
  79. GRB 210626A: Swift-XRT afterglow detection
  80. GRB 210622A: Swift-XRT observations
  81. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154
  82. GRB 210618A: Swift-XRT afterglow detection
  83. GRB 210619B: Even further SAO RAS optical observations
  84. GRB 210622A: Fermi GBM detection
  85. GRB 210619B: Further SAO RAS optical observations
  86. GRB 210619B: iTelescope optical afterglow observation
  87. GRB 210619B: SAO RAS optical observations
  88. GRB 210619B: GIT optical follow-up and confirmation of jet-break
  89. GRB 210619B: Fermi GBM detection
  90. GRB 210619B: Fermi-LAT detection
  91. GRB 210619B: Swift-XRT refined Analysis
  92. GRB 210618A: Fermi GBM observation
  93. GRB 210618A: Swift-XRT observations
  94. GRB 201008A: Fermi GBM observation
  95. GRB 210323B: Fermi GBM observation
  96. Fermi GRB 210615A: Global MASTER-Net observations report
  97. Swift ToO Observations of HAWC transient J0020+3108
  98. GRB 210605B: Swift-XRT afterglow detection
  99. GRB 210610A: Fermi GBM observations
  100. GRB 210610B: Further SAO RAS optical observations

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