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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"

8476 results found.

  1. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  2. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  3. IceCube-230201A: Upper limits from a search for additional neutrino events in IceCube
  4. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  5. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  6. IceCube-230201A - IceCube observation of a high-energy neutrino candidate track-like event
  7. GRB 221009A: radio afterglow detection with the EVN
  8. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  9. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  10. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  11. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  12. AT2023avj ZTF Candidate: Assy optical observations
  13. ZTF and LT Observations of AT2023avj, a Candidate Optical Afterglow
  14. IceCube-230122A: Upper limits from a search for additional neutrino events in IceCube
  15. GRB 230123A: Swift detection of a burst
  16. IceCube-230122A - IceCube observation of a high-energy neutrino candidate track-like event
  17. GRB 230116D: Swift detection of a burst
  18. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  19. IceCube-230112A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  21. IceCube-230112A - IceCube observation of a high-energy neutrino candidate track-like event
  22. IceCube-Cascade 230109A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 221231A: 3.6m DOT optical upper limit
  24. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  25. GRB 221231A: Swift ToO observations
  26. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  28. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  29. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  30. IceCube-221224A: Upper limits from a search for additional neutrino events in IceCube
  31. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  32. GRB 221226B: Swift detection of a burst
  33. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  34. IceCube-221223A: BOOTES-4/MET Optical Observations
  35. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  37. GRB 221218A: 3.6m DOT optical upper limit
  38. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  39. GRB 221218A: KAIT Optical Upper Limit
  40. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  41. GRB 221215A: Fermi GBM Detection
  42. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 221216A: Swift detection of a burst
  44. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  45. GRB 221215A: Swift ToO observations
  46. Konus-Wind detection of GRB 221209A
  47. IceCube-221210A: Upper limits from a search for additional neutrino events in IceCube
  48. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  49. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  50. GRB 221206B: Swift ToO observations
  51. GRB 221202A: Swift detection of a burst
  52. GRB 221201A: Swift detection of a burst
  53. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  54. IceCube-221124A: BOOTES-4/MET and BOOTES-2/TELMA optical upper limit
  55. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  56. GRB221120A: WIRC near-IR imaging of the afterglow candidate
  57. GRB 221120A: Liverpool Telescope Upper Limits
  58. GRB 221120A: Archival PS1 Imaging of Faint Source near XRT position
  59. GRB 221120A: LDT Optical Afterglow Candidate
  60. GRB 221120A: Swift detection of a likely short burst
  61. GRB 221119A: Detection by GRBAlpha
  62. GRB 221110A: GRANDMA observations
  63. GRB 221110A: LCOGT Optical Afterglow Detection
  64. GRB 221110A: Swift detection of a burst with an optical counterpart
  65. IceCube-221104A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-221104A - IceCube observation of a high-energy neutrino candidate track-like event
  67. High-precision position of the compact radio counterpart to GRB221009A
  68. GRB 221027B: Swift detection of a burst
  69. GRB 221024A: D50 candidate afterglow
  70. GRB 221022A: Swift ToO observations
  71. GRB 221024A: Swift detection of a burst
  72. GRB 221022A: Swift/BAT-GUANO detection
  73. The probability of observing GRB 221009A at z = 0.151
  74. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 October 17
  75. GRB 221017A: Swift ToO observations
  76. GRB 221016A: Swift detection of a burst
  77. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  78. MAXI GRB 221006A: Redshifts of the possible host galaxies
  79. GRB 221009A: search for neutrinos with KM3NeT
  80. Afterglow limits of GRB 221006A from OHP
  81. GRB 221009A/Swift J1913.1+1946: SMA observations
  82. GRB 221006A: Swift ToO observations
  83. Konus-Wind detection of GRB 221009A
  84. GRB 221009A: Upper limits from a neutrino search with IceCube
  85. GRB 221009A / Swift J1913.1+1946: GIT detection of the optical afterglow
  86. GRB 221009A/Swift J1913.1+1946: AMI-LA observations
  87. Swift J1913.1+1946 a new bright hard X-ray and optical transient
  88. GRB 221008A: Tiled Swift observations
  89. GRB 221006A: Tiled Swift observations
  90. GRB 220921A: ATCA detection of radio counterpart
  91. GRB 220930A: Swift detection of a burst
  92. IceCube-220928A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-220928A - IceCube observation of a high-energy neutrino candidate track-like event
  94. GRB 220921A: LCOGT Optical Observations
  95. GRB 220926A: Swift detection of a burst
  96. IceCube-220907A: Classification of AT2022oyn as a Type Ia supernova
  97. GRB 220921A: Tiled Swift observations
  98. IceCube-220918A: Upper limits from a search for additional neutrino events in IceCube
  99. IceCube-220918A - IceCube observation of a high-energy neutrino candidate track-like event
  100. IceCube-220907A: No significant detection in HAWC

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