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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"

7446 results found.

  1. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  2. GRB 220403B: Swift detection of a burst with an optical counterpart
  3. Swift Trigger 1100848 is likely not a GRB
  4. GRB 220325A: Swift detection of a burst
  5. GRB 220319A: Swift detection of a burst
  6. GRB 220310A: MITSuME Akeno optical observation
  7. IceCube-220317A - IceCube observation of a high-energy neutrino candidate track-like event
  8. GRB 220310C: Swift ToO observations
  9. GRB 220310C: Swift/BAT-GUANO candidate arcminute localization
  10. GRB 220311A: MASTER OT retraction
  11. GRB 220310A: Swift ToO observations
  12. GRB 220306B: Mondy optical observations, confirmation afterglow candidate
  13. GRB 220306B: AbAO optical observations, possible afterglow candidate
  14. GRB 220306B: Swift detection of a burst
  15. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  17. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 220302A: Swift afterglow detection
  20. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 220219B: Swift-XRT observations
  22. GRB 220219B: Swift ToO observations
  23. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  24. ZTF22aaajecp/AT2022cmc: GMOS-N spectroscopy
  25. GRB 220210A: Mondy, AbAO and Terskol optical upper limits
  26. GRB 220210A: BOOTES-5/JGT optical afterglow candidate discarded
  27. GRB 220210A: BOOTES-5/JGT optical afterglow candidate
  28. GRB 210919A: Maidanak optical observations
  29. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  30. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  31. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  33. GRB 211227A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  34. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  35. IceCube-211208A: the optical observation of the candidate PKS0735+178
  36. GRB 220118A: MITSuME Akeno optical observation
  37. GRB 220118A: Swift detection of a burst with an optical counterpart
  38. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  39. AMON IC_HAWC NuEm-220116A: No neutrino counterpart detected with ANTARES
  40. GRB 220117B: Swift detection of a burst
  41. GRB 220117A: Swift detection of a burst
  42. GRB 210919A: LBT spectroscopic redshift of the host galaxy candidates
  43. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  44. GRB 220107B: Nanshan/NEXT optical upper limits and host galaxy candidate
  45. GRB 220107A: MITSuME Akeno optical observation
  46. GRB 220107B: Tiled Swift observations
  47. GRB 220107A: Swift ToO observations
  48. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  49. GRB 211229A: Swift ToO observations
  50. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  51. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  52. GRB 211227A: Swift detection of a burst
  53. GRB 211221A: Swift detection of a burst
  54. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  55. IceCube-211216B: Upper limits from Fermi-GBM Observations
  56. IceCube-211216A: Upper limits from Fermi-GBM Observations
  57. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  58. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  60. GRB 211211A - Gemini K-band detection
  61. Chandra observation of GW170817 at ~1575 days since merger (all epochs)
  62. IceCube-211208A: No neutrino counterpart detected with ANTARES
  63. GRB 211211A: MITSuME Akeno optical observation
  64. GRB 211211A: Nanshan/NEXT optical observations
  65. GRB 211211A: KAIT Optical Afterglow Candidate
  66. GRB 211211A: Swift detection of a bright burst
  67. AMON NuEm-211020A: No neutrino counterpart detected with ANTARES
  68. GRB 211130A: MeerLICHT identification of possible afterglow candidate
  69. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  70. Chandra observation of GW170817 at ~1573 days since merger (Epoch 1 of 4)
  71. GRB 211207A: Swift detection of a burst with an optical counterpart
  72. GRB 211203A: Swift detection of a burst
  73. GRB 211129A: Swift detection of a burst
  74. IceCube-211125A: No neutrino counterpart detected with ANTARES
  75. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  76. IceCube-211123A: Upper limits from Fermi-GBM Observations
  77. IceCube-211117A: not observable by Fermi-GBM
  78. IceCube-211116A: not observable by Fermi-GBM
  79. IceCube-211023A: not observable by Fermi-GBM
  80. HAWC-211123A: not observable by Fermi-GBM
  81. HAWC-211123A: No neutrino counterpart detected with ANTARES
  82. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  83. Trigger_21473: Tiled Swift observations
  84. Search for counterpart to IceCube-211117A with ANTARES
  85. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  86. IceCube-211116A: No neutrino counterpart detected with ANTARES
  87. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  88. GRB 211106A: Swift/UVOT upper limits
  89. Short GRB 211106A: spectroscopy of galaxies in the field
  90. MeerLICHT follow-up of GRB 211106A
  91. GRB 211107B: Swift ToO observations
  92. GRB 211106A: Swift-XRT observations
  93. GRB 211106A: Swift ToO observations
  94. GRB 211106A: Swift/BAT-GUANO candidate arcminute localization of a short burst
  95. Swift Trigger 1082569 is probably not a GRB
  96. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  97. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  98. GRB 211024A: Possible afterglow candidate from GIT
  99. GRB 211024A: Swift ToO observations
  100. GRB 211024A: Swift/BAT-GUANO detection and candidate arcminute localization of a short burst

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