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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"

8474 results found.

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

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