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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-220421A - IceCube observation of a high-energy neutrino candidate track-like event
  2. GRB 220418B: Swift ToO observations
  3. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  4. GRB 220412B: TNG optical observations
  5. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  6. GRB 220412A: BOOTES-network optical upper limits
  7. GRB 220412A: RATIR Observations of the Fading Afterglow
  8. GRB 220412B: Swift detection of a short burst
  9. GRB 220412A: RATIR Afterglow Candidate
  10. GRB 220412A: Swift detection of a burst
  11. GRB 220408A: NOT optical observations and archival detection
  12. GRB 220403C: Swift ToO observations
  13. GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
  14. IceCube-220405A: No Candidate Counterparts from the Zwicky Transient Facility
  15. IceCube-220405B: No Candidate Counterparts from the Zwicky Transient Facility
  16. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  17. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  18. GRB 220403B: Swift detection of a burst with an optical counterpart
  19. Swift Trigger 1100848 is likely not a GRB
  20. Fermi GBM Sub-Threshold Detection of GRB 220325A
  21. GRB 220325A: Swift detection of a burst
  22. GRB 220319A: Swift detection of a burst
  23. IceCube-220317A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 220310A: MITSuME Akeno optical observation
  25. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  26. GRB 220310C: Swift ToO observations
  27. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  28. GRB 220311A: MASTER OT retraction
  29. Fermi GBM Detection of GRB 220308A
  30. GRB 220310A: Swift ToO observations
  31. IceCube-220306A: No significant detection in HAWC
  32. IceCube-220303A: No significant detection in HAWC
  33. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  34. IceCube-220306A: Upper limits from a search for additional neutrino events in IceCube
  35. IceCube-220304A: Upper limits from a search for additional neutrino events in IceCube
  36. GRB 220306B: AbAO optical observations, possible afterglow candidate
  37. GRB 220306B: Swift detection of a burst
  38. Fermi GBM Sub-Threshold Detection of GRB 220305A
  39. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  40. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  41. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  43. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  44. GRB 220302A: Swift afterglow detection
  45. Konus-Wind detection of GRB 220222A
  46. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  47. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  48. ZTF22aaajecp/AT2022cmc: DECam Photometry
  49. GRB 220219B: Swift-XRT observations
  50. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 220219B: Swift ToO observations
  52. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  53. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  54. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  55. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  56. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  57. GRB 210919A: Maidanak optical observations
  58. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  60. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  61. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  62. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  64. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  65. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  66. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube-211208A: the optical observation of the candidate PKS0735+178
  68. Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
  69. GRB 220118A: MITSuME Akeno optical observation
  70. GRB 220118A: Swift detection of a burst with an optical counterpart
  71. Fermi GBM Sub-Threshold Detection of GRB 220117A
  72. IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube
  73. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  74. AMON IC_HAWC NuEm-220116A: No neutrino counterpart detected with ANTARES
  75. GRB 220117B: Swift detection of a burst
  76. GRB 220117A: Swift detection of a burst
  77. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  78. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  80. GRB 220107A: MITSuME Akeno optical observation
  81. GRB 220107B: Tiled Swift observations
  82. GRB 220107A: Swift ToO observations
  83. GRB 211227A: Gemini South Optical Observations
  84. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  85. GRB 211229A: Swift ToO observations
  86. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  87. GRB 211227A: Swift detection of a burst
  88. Fermi GBM Sub-Threshold Detection of GRB 211221A
  89. Fermi GBM Sub-Threshold Detection of GRB 211207A
  90. GRB 211221A: Swift detection of a burst
  91. IceCube-211216B: No significant detection in HAWC
  92. IceCube-211216A: No significant detection in HAWC
  93. GRB 211216A: Fermi GBM observation
  94. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  95. IceCube-211216B: Upper limits from Fermi-GBM Observations
  96. IceCube-211216A: Upper limits from Fermi-GBM Observations
  97. IceCube-211216A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  99. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  100. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event

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