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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"

8485 results found.

  1. IceCube-201021A: Upper limits from Fermi-GBM Observations
  2. GRB 201021C: Swift detection of a burst with an optical counterpart
  3. HAWC-201019A: No Neutrino Counterpart detected with ANTARES
  4. GRB200826A: GMOS-N detection of a supernova bump
  5. GRB 201020B: Swift ToO observations
  6. IceCube-201021A: IceCube observation of a high-energy neutrino candidate event
  7. GRB 201020A: Swift detection of a burst with an optical counterpart.
  8. GRB 201015A: 6 GHz VLA radio afterglow candidate detection
  9. GRB 201013A: 3.6m DOT Optical Observations
  10. GRB 201017A: Assy and Mondy optical observations, possible afterglow detection
  11. GRB 201017A: Swift detection of a burst
  12. Fermi GBM Sub-Threshold Detection of GRB 201015A
  13. IceCube-201014A: No significant detection in HAWC
  14. GRB 201015A: NOT optical afterglow confirmation
  15. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  16. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  17. Swift Trigger 1000255 is probably not a GRB
  18. GRB 201013A: TSHAO and AbAO optical observations, afterglow confirmation
  19. IceCube-201014A: Not observable by GBM
  20. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 201013A: FRAM-ORM possible afterglow candidate
  22. GRB 201013A: Swift/UVOT Upper Limits
  23. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  24. GRB 201013A: Swift detection of a burst
  25. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  26. IceCube-201007A: No significant detection in HAWC
  27. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 201008A: Swift ToO observations
  29. IceCube-201007A: Upper limits from Fermi-GBM Observations
  30. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  31. GRB 201006A: Swift detection of a burst
  32. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  33. IceCube-200929A: No significant detection in HAWC
  34. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  35. GRB 201001A: Swift detection of a burst
  36. IceCube-200929A: Upper limits from Fermi-GBM Observations
  37. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  38. IceCube-200926B: No significant detection in HAWC
  39. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  40. IceCube-200926B: Upper limits from Fermi-GBM Observations
  41. IceCube-200926A: Upper limits from Fermi-GBM Observations
  42. IceCube-200926A: No significant detection in HAWC
  43. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  44. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  45. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  46. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  47. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  48. IceCube-200926A: IceCube observation of a high-energy neutrino candidate event
  49. Swift GRB 200925B: Global MASTER-Net OT detection
  50. GRB 200925B: OSN Afterglow Candidate Discovery
  51. GRB 200925B: Swift detection of a burst
  52. GRB 200922A: chance superposition between optical afterglow and archival star
  53. IceCube-200921A: Upper limits from a search for additional neutrino events in IceCube
  54. GRB 200922A: Swift-BAT refined analysis
  55. IceCube-200921A: no significant detection in HAWC observations
  56. IceCube-200921A: Upper limits from Fermi-GBM Observations
  57. IceCube-200921A: IceCube observation of a high-energy neutrino candidate event
  58. IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
  59. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  60. IceCube-200916A: Upper limits from a search for additional neutrino events in IceCube
  61. IceCube-200916A: No significant detection in HAWC
  62. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  63. Fermi-GBM Sub-Threshold Detection of GRB 200917A
  64. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  65. IceCube-200916A: Upper limits from Fermi-GBM Observations
  66. GRB 200917A: Swift detection of a burst
  67. IceCube-200916A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube-200911A: No significant detection in HAWC
  69. GRB 200914A: Swift ToO observations
  70. IceCube-200911A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-200911A: No neutrino counterpart candidates in ANTARES search
  72. IceCube-200911A: not observable by Fermi-GBM
  73. IceCube-200911A: IceCube observation of a high-energy neutrino candidate event
  74. GRB 200907B: Swift detection of a short burst
  75. GRB 200906A: Swift detection of a burst
  76. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  77. GRB 200901B: Swift detection of a burst
  78. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  79. GRB 200829A: Swift detection of a burst with an optical afterglow
  80. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  81. GRB 200826A: VLA Detection at 6 GHz
  82. GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
  83. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  84. GRB 200826A: Tiled Swift observations
  85. Swift Trigger 992444: a possible GRB 200821A
  86. GRB 200729A: Lowell Discovery Telescope observations
  87. GRB 200819A: Swift detection of a burst
  88. Swift trigger 990358 is not an astrophysical source
  89. Swift trigger 989458 is likely not an astrophysical source
  90. IceCube200806A: No significant detection in HAWC
  91. GRB 200809B: Swift ToO observations
  92. IceCube-200806A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-200806A: Upper limits from Fermi-GBM Observations
  94. GRB 200806A: Swift detection of a burst
  95. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  96. GRB 200803A: Fermi GBM detection
  97. GRB 200803A: Tiled Swift observations
  98. AX J1846.4-0258: Swift-BAT refined analysis
  99. Konus-Wind detection of GRB 200729A
  100. Swift Detection of an SGR-like flare from AX J1846.4-0258

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