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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"

8473 results found.

  1. IceCube-220907A: One Candidate Counterpart from the Zwicky Transient Facility
  2. GRB 220831A: ATCA 5/9 GHz radio observations
  3. IceCube-220907A - IceCube observation of a high-energy neutrino candidate track-like event
  4. GRB 220831A: Swift-UVOT Upper Limits
  5. Introducing Self-Service Configuration of GCN Notices over Email for Transient Alerts
  6. GRB 220831A: DECam detection of a possible optical counterpart
  7. GRB 220831A: Swift ToO observations
  8. IceCube-220822A: No significant detection in HAWC
  9. IceCube-Cascade 220826A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-220822A: Classification of AT2022saw as a Type Ia supernova
  11. GRB 220826A: Swift detection of a burst with an optical counterpart
  12. IceCube-220822A: Upper limits from a search for additional neutrino events in IceCube
  13. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  14. IceCube-220822A - IceCube observation of a high-energy neutrino candidate track-like event
  15. GRB 220810A: Further Swift-XRT observations
  16. GRB 220813A: Swift detection of a burst with an optical counterpart
  17. GRB 220810A: Swift-XRT observations
  18. GRB 220810A: Swift ToO observations
  19. GRB 220810A: MeerLICHT detection of two afterglow candidates
  20. GRB 220627A: MeerKAT radio observations
  21. IceCube Astrotrack Bronze 136918_45252263.amon is likely background
  22. GRB 220730A: Swift detection of a short hard burst
  23. GRB 220715B: Swift detection of a burst
  24. GRB 220714B: UVOT afterglow discovery
  25. GRB 220714B: Swift detection of a burst
  26. GRB 220712B: NOT optical afterglow confirmation
  27. GRB 220710A: Swift ToO observations
  28. GRB 220711B: NOT optical observations
  29. GRB 220711B: Swift detection of a burst
  30. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  31. GRB 220708B: Swift ToO observations
  32. GRB 220627A: ATCA detection of radio counterpart
  33. GRB 220706A: Swift detection of a burst
  34. GRB 220701A: Keck/LRIS Optical Upper Limit
  35. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  36. GRB 200701A: KAIT Optical Upper Limit
  37. GRB 220701A: Swift detection of a burst
  38. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  39. IceCube-220629A: No significant detection in HAWC
  40. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  41. IceCube-220627A: No significant detection in HAWC
  42. GRB 220627A: Swift-XRT afterglow detection
  43. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  44. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  45. GRB 220627A: VLT MUSE redshift
  46. GRB 220627A: MeerLICHT candidate optical afterglow
  47. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  48. GRB 220627A: Swift ToO observations
  49. GRB 220627A: MeerLICHT detection of two afterglow candidates
  50. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  51. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  52. IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
  53. IceCube-220624A: No significant detection in HAWC
  54. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  55. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  56. GRB 220617A: TNG optical observations
  57. GRB 220611A optical counterpart
  58. GRB 220618A: Swift detection of a burst
  59. GRB 220617B: Swift ToO observations
  60. GRB 220611A: Swift detection of a burst
  61. GRB 220606B: Gemini South Optical Observations
  62. GRB 220606B: Swift follow-up observations
  63. GRB 220606B: GUANO coordinate correction to GCN 32167
  64. GRB 220606B: Swift ToO observations
  65. GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  66. GRB 220527A: Swift ToO observations
  67. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
  68. IceCube-220524A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 220521A: Swift detection of a burst
  71. GRB 220518A: Swift detection of a burst
  72. IceCube-220513A: Upper limits from a search for additional neutrino events in IceCube
  73. GRB 220514B: Tiled Swift observations
  74. IceCube-220513A: No significant detection in HAWC
  75. GRB 220514A: MeerLICHT optical afterglow candidate
  76. IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
  77. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  78. IceCube-220509A: No significant detection in HAWC
  79. GRB 220511A: Fermi GBM observation
  80. GRB 220511A: Swift ToO observations
  81. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  82. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  83. GRB 220506A: Tiled Swift observations
  84. IceCube-220405B - ZTF19aavnpjv unrelated
  85. IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
  86. GRB 220501A: Swift-BAT refined analysis
  87. IceCube-220501A: No Candidate Counterparts from the Zwicky Transient Facility
  88. GRB 220501A: Fermi GBM observation
  89. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 220430A: CAHA 2.2m telescope optical limit
  91. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
  92. IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
  94. IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
  95. GRB 220426A: Tiled Swift observations
  96. GRB 220427A: Swift detection of a burst with an optical counterpart
  97. Fermi-LAT Gamma-ray Observations of IceCube-220425A
  98. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  99. IceCube-220425A - IceCube observation of a high-energy neutrino candidate track-like event
  100. IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event

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