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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"

8480 results found.

  1. IceCube-201021A: IceCube observation of a high-energy neutrino candidate event
  2. GRB 201020A: Swift detection of a burst with an optical counterpart.
  3. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  4. GRB 201013A: 3.6m DOT Optical Observations
  5. GRB 201017A: Assy and Mondy optical observations, possible afterglow detection
  6. GRB 201017A: Swift detection of a burst
  7. Fermi GBM Sub-Threshold Detection of GRB 201015A
  8. IceCube-201014A: No significant detection in HAWC
  9. GRB 201015A: NOT optical afterglow confirmation
  10. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  12. Swift Trigger 1000255 is probably not a GRB
  13. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  14. IceCube-201014A: Not observable by GBM
  15. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  16. GRB 201013A: FRAM-ORM possible afterglow candidate
  17. GRB 201013A: Swift/UVOT Upper Limits
  18. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  19. GRB 201013A: Swift detection of a burst
  20. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  21. IceCube-201007A: No significant detection in HAWC
  22. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 201008A: Swift ToO observations
  24. IceCube-201007A: Upper limits from Fermi-GBM Observations
  25. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  26. GRB 201006A: Swift detection of a burst
  27. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  28. IceCube-200929A: No significant detection in HAWC
  29. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  30. GRB 201001A: Swift detection of a burst
  31. IceCube-200929A: Upper limits from Fermi-GBM Observations
  32. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  33. IceCube-200926B: No significant detection in HAWC
  34. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  35. IceCube-200926B: Upper limits from Fermi-GBM Observations
  36. IceCube-200926A: Upper limits from Fermi-GBM Observations
  37. IceCube-200926A: No significant detection in HAWC
  38. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  39. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  41. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  42. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  43. IceCube-200926A: IceCube observation of a high-energy neutrino candidate event
  44. Swift GRB 200925B: Global MASTER-Net OT detection
  45. GRB 200925B: OSN Afterglow Candidate Discovery
  46. GRB 200925B: Swift detection of a burst
  47. GRB 200922A: chance superposition between optical afterglow and archival star
  48. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  49. GRB 200922A: Swift-BAT refined analysis
  50. IceCube-200921A: no significant detection in HAWC observations
  51. IceCube-200921A: Upper limits from Fermi-GBM Observations
  52. IceCube-200921A: IceCube observation of a high-energy neutrino candidate event
  53. IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
  54. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  55. IceCube-200916A: Upper limits from a search for additional neutrino events in IceCube
  56. IceCube-200916A: No significant detection in HAWC
  57. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  58. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  59. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  60. IceCube-200916A: Upper limits from Fermi-GBM Observations
  61. GRB 200917A: Swift detection of a burst
  62. IceCube-200916A - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube-200911A: No significant detection in HAWC
  64. GRB 200914A: Swift ToO observations
  65. IceCube-200911A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-200911A: No neutrino counterpart candidates in ANTARES search
  67. IceCube-200911A: not observable by Fermi-GBM
  68. IceCube-200911A: IceCube observation of a high-energy neutrino candidate event
  69. GRB 200907B: Swift detection of a short burst
  70. GRB 200906A: Swift detection of a burst
  71. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  72. GRB 200901B: Swift detection of a burst
  73. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  74. GRB 200829A: Swift detection of a burst with an optical afterglow
  75. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  76. GRB 200826A: VLA Detection at 6 GHz
  77. GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
  78. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  79. GRB 200826A: Tiled Swift observations
  80. Swift Trigger 992444: a possible GRB 200821A
  81. GRB 200729A: Lowell Discovery Telescope observations
  82. GRB 200819A: Swift detection of a burst
  83. Swift trigger 990358 is not an astrophysical source
  84. Swift trigger 989458 is likely not an astrophysical source
  85. IceCube200806A: No significant detection in HAWC
  86. GRB 200809B: Swift ToO observations
  87. IceCube-200806A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-200806A: Upper limits from Fermi-GBM Observations
  89. GRB 200806A: Swift detection of a burst
  90. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  91. GRB 200803A: Fermi GBM detection
  92. GRB 200803A: Tiled Swift observations
  93. AX J1846.4-0258: Swift-BAT refined analysis
  94. Konus-Wind detection of GRB 200729A
  95. Swift Detection of an SGR-like flare from AX J1846.4-0258
  96. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  97. GRB 200729A: IceCube neutrino search
  98. GRB 200729A: Spitzer archival source detection
  99. GRB 200729A: NOT optical upper limits
  100. GRB 200729A: Swift detection of a burst

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