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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"

7448 results found.

  1. GRB 201015A: NOT optical afterglow confirmation
  2. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  3. Swift Trigger 1000255 is probably not a GRB
  4. IceCube-201014A: Not observable by GBM
  5. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 201013A: FRAM-ORM possible afterglow candidate
  7. GRB 201013A: Swift/UVOT Upper Limits
  8. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  9. GRB 201013A: Swift detection of a burst
  10. Swift detection of a new SGR 1830-0645 or a short GRB 201010A
  11. GRB 201008A: Swift ToO observations
  12. IceCube-201007A: Upper limits from Fermi-GBM Observations
  13. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  14. GRB 201006A: Swift detection of a burst
  15. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  16. GRB 201001A: Swift detection of a burst
  17. IceCube-200929A: Upper limits from Fermi-GBM Observations
  18. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  19. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  20. IceCube-200926B: Upper limits from Fermi-GBM Observations
  21. IceCube-200926A: Upper limits from Fermi-GBM Observations
  22. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  23. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  24. IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
  25. IceCube-200926A: IceCube observation of a high-energy neutrino candidate event
  26. Swift GRB 200925B: Global MASTER-Net OT detection
  27. GRB 200925B: OSN Afterglow Candidate Discovery
  28. GRB 200925B: Swift detection of a burst
  29. IceCube-200921A: Upper limits from Fermi-GBM Observations
  30. IceCube-200921A: IceCube observation of a high-energy neutrino candidate event
  31. IceCube-200916A - ZTF20acaapwk/SN2020tno classified as SN Ia
  32. IceCube-200916A: AbAO observations of optical candidates ZTF20acaapwk/AT2020tno, ZTF20acaapwo/AT2020tnp
  33. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  34. IceCube-200916A: Two Candidate Counterparts from the Zwicky Transient Facility
  35. IceCube-200916A: Upper limits from Fermi-GBM Observations
  36. GRB 200917A: Swift detection of a burst
  37. IceCube-200916A - IceCube observation of a high-energy neutrino candidate track-like event
  38. GRB 200914A: Swift ToO observations
  39. IceCube-200911A: No neutrino counterpart candidates in ANTARES search
  40. IceCube-200911A: not observable by Fermi-GBM
  41. IceCube-200911A: IceCube observation of a high-energy neutrino candidate event
  42. GRB 200907B: Swift detection of a short burst
  43. GRB 200906A: Swift detection of a burst
  44. ZTF20abtxwfx/AT2020sev : AstroSat CZTI non-detection of a transient
  45. GRB 200901B: Swift detection of a burst
  46. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  47. GRB 200829A: Swift detection of a burst with an optical afterglow
  48. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  49. GRB 200826A: VLA Detection at 6 GHz
  50. GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
  51. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  52. GRB 200826A: Tiled Swift observations
  53. Swift Trigger 992444: a possible GRB 200821A
  54. GRB 200819A: Swift detection of a burst
  55. Swift trigger 990358 is not an astrophysical source
  56. Swift trigger 989458 is likely not an astrophysical source
  57. GRB 200809B: Swift ToO observations
  58. IceCube-200806A: Upper limits from Fermi-GBM Observations
  59. GRB 200806A: Swift detection of a burst
  60. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  61. GRB 200803A: Fermi GBM detection
  62. GRB 200803A: Tiled Swift observations
  63. Konus-Wind detection of GRB 200729A
  64. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  65. GRB 200729A: NOT optical upper limits
  66. GRB 200729A: Swift detection of a burst
  67. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  68. GRB 200723A: Swift ToO observations
  69. GRB 200723A: GOTO candidate afterglow and host galaxy
  70. AMON IC_HAWC 170720: No Neutrino Counterpart detected with ANTARES
  71. GRB 200716C: Optical observations from HCT
  72. GRB 200522A: HST NIR counterpart confirmation
  73. GRB 200716C: Swift detection of a burst with an optical counterpart
  74. GRB 200715A: Swift ToO observations
  75. GRB 200714E: Swift ToO observations
  76. GRB 200522A: Candidate Optical/nIR Counterpart from Gemini and HST Imaging
  77. GRB 200713A: Swift detection of a burst
  78. GRB 200711A: KAIT Optical Upper Limit
  79. GRB 200711A: Swift detection of a burst
  80. GRB 200709B/HAWC-200907A: Swift-XRT further observations
  81. HAWC-200907A: No Neutrino Counterpart detected with ANTARES
  82. GRB 200709B: Tiled Swift observations
  83. Trigger 980513: Swift detection of SGR Swift J1818.0-1607
  84. GRB 200630A: Swift detection of a burst
  85. GRB 200623A: Further MMTCam Observations of XRT Source #3
  86. GRB 200623A: LBT optical observations
  87. GRB 200625A: Swift ToO observations
  88. GRB 200623A: Swift/UVOT Upper Limits
  89. GRB 200623A: OAJ deep multi-color imaging, XRT #2 is pre-detected
  90. GRB 200623A: TNG optical observations
  91. GRB 200623A: AbAO afterglow candidate within XRT #2
  92. GRB 200623A: Swift ToO observations
  93. IceCube-200620A: MASTER previous detection of ZTF20abgvabi/AT2020ncr
  94. IceCube-200620A: not observable by Fermi-GBM
  95. IceCube-200620A: One Candidate Counterpart from the Zwicky Transient Facility
  96. IceCube-200620A: No ANTARES neutrino counterpart
  97. IceCube-200620A - IceCube observation of a high-energy neutrino candidate track-like event
  98. LIGO/Virgo MS200618aq: Retraction of a test binary neutron star candidate
  99. LIGO/Virgo MS200619bf: Retraction of a test binary neutron star candidate
  100. LIGO/Virgo MS200618bx: Retraction of a test binary neutron star candidate

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