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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"
  1. SWIFT GRB190324.95 Global MASTER-Net observations report
  2. Fermi Trigger 575160247 / GRB 190324947: BALROG localization
  3. GRB 190324A: Swift detection of a burst
  4. Fermi Trigger 575108474 / GRB 190324348: BALROG localization
  5. SWIFT GRB190323.85 Global MASTER-Net observations report
  6. Fermi Trigger 575067924 / GRB 190323879: BALROG localization
  7. Swift detection of LS I +61 303
  8. Fermi Trigger 575018216 / GRB 190323303: BALROG localization
  9. Correction: Chandra observations of GW170817 ~581 days since merger
  10. Chandra observations of GW170817 ~581 days since merger
  11. Swift Trigger 894268: Detection of GRO J2058+42 in outburst
  12. Fermi Trigger 574850558 / GRB 190321363: BALROG localization
  13. GRB 190114C: photometric detection of a SN component
  14. GRB 190320A: Swift/UVOT Upper Limits
  15. GRB 190320A: Swift-XRT refined Analysis
  16. GRB 190320A: Swift-BAT refined analysis
  17. GRB190320A: MASTER GRB counterpart decay
  18. GRB 190320A: Fermi GBM observation
  19. GRB 190320A: Enhanced Swift-XRT position
  20. GRB190320A: MASTER OT detection
  21. SWIFT GRB190320.05 Global MASTER-Net observations report
  22. GRB 190320A: Swift-XRT observations
  23. GRB 190320A: Swift detection of a burst
  24. GRB 190315A: AstroSat CZTI detection
  25. Fermi Trigger 574678842 / GRB 190319375: BALROG localization
  26. Fermi Trigger 574676902 / GRB 190319353: BALROG localization
  27. Fermi Trigger 574345067 / GRB 190315512: BALROG localization
  28. GRB190311A: MITSuME Akeno optical observation
  29. Fermi trigger 574140965 / GRB190313.15: MASTER Global Robotic Net optical observation
  30. GRB 190311A: OSN optical afterglow detection
  31. GRB 190311A: Swift/UVOT Detection
  32. GRB 190311A: Mondy optical observations
  33. GRB 190311A: Liverpool Telescope observations
  34. GRB 190311A: NOT optical counterpart
  35. GRB 190311A: Swift-BAT refined analysis
  36. GRB190305A: MASTER Global Robotic Net optical observation
  37. GRB190311A: OAO observations
  38. GRB 190311A: Mondy optical observations
  39. Fermi Trigger 574080135 / GRB 190312446: BALROG localization
  40. Improved Fermi/GBM GRB localizations
  41. [Hxmt-ba]GRB 190310A: Insight-HXMT/HE detection
  42. GRB 190311A: GMG observation
  43. GRB 190311A: Fermi GBM observation
  44. GRB 190311A: Swift-XRT refined Analysis
  45. GRB 190311A: TSHAO optical observations
  46. GRB 190311A: Enhanced Swift-XRT position
  47. GRB190311A: MASTER Global Robotic Net OT optical observation
  48. GRB 190311A: NEXT-0.6m optical afterglow detection
  49. GRB 190311A: Mondy optical observations
  50. GRB 190311A: Swift detection of a burst with optical counterpart
  51. GRB 190305A: Swift-XRT afterglow detection
  52. GRB 190305A: CALET Gamma-Ray Burst Monitor detection
  53. Konus-Wind observation of GRB 190304A
  54. IPN Triangulation of GRB 190304A (long)
  55. GRB 190306A: Swift-XRT observations
  56. GRB 190306B: Insight-HXMT/HE detection
  57. Konus-Wind observation of GRB 190305A
  58. GRB 190306A: Tiled Swift observations
  59. GRB 190306A: MAXI/GSC detection
  60. IPN Triangulation of GRB 190305A
  61. GRB 190305A: Swift-XRT observations
  62. GRB 190305A: Insight-HXMT/HE detection
  63. GRB 190305A: MAXI/GSC detection
  64. Swift Trigger 891843 is not a GRB
  65. GRB 190305A: Tiled Swift observations
  66. GRB 190305A: AGILE/MCAL detection of a burst
  67. GRB 190226A: Insight-HXMT/HE detection
  68. Trigger 890732: Swift detection of MAXI J1631-479
  69. INTEGRAL observation of IceCube-190221A
  70. Search for additional neutrino events from the direction of IceCube-190221A with IceCube
  71. IceCube-190221A: Swift-XRT Follow-up Observations
  72. IceCube-190221A: Fermi-LAT Gamma-ray observations
  73. Fermi-GBM Observations of IceCube-190221A
  74. IceCube-190221A: MASTER Global Robotic Net optical observation
  75. GRB 190220B: Fermi GBM observation
  76. GRB 190219A: CrAO and AbAO optical upper limit
  77. GRB 190220B: Kitab Observatory optical upper limit
  78. IceCube-190221A - IceCube observation of a high-energy neutrino candidate event
  79. GRB 190220A: Swift-XRT refined Analysis
  80. GRB 190220B: BOOTES-4 optical observation
  81. GRB 190220B: a long GRB detected by IBAS
  82. GRB 190220A: Swift-BAT refined analysis
  83. GRB 190219A: Swift-BAT refined analysis
  84. GRB 190220A: Enhanced Swift-XRT position
  85. GRB 190219A: NOT optical afterglow candidate
  86. GRB 190219A: NEXT-0.6m optical upper limit
  87. GRB 190219A: Swift-XRT refined Analysis
  88. GRB 190220A: Swift detection of a burst with an optical counterpart
  89. GRB 190219A: Enhanced Swift-XRT position
  90. GRB 190219A: CAHA 2.2m observations
  91. GRB190219A: MASTER Global Robotic Net optical observation
  92. GRB 190219A: BOOTES-1 optical limits
  93. GRB 190219A: Prompt enhanced Swift-XRT position
  94. GRB 190219A: Swift detection of a burst
  95. GRB 190215A: AstroSat CZTI detection
  96. Trigger 889483: Swift detection of Swift J1858.6-0814
  97. GRB 190215A: Insight-HXMT/HE detection
  98. GRB 190215A: Fermi GBM detection
  99. GRB 190212A: Insight-HXMT/HE detection
  100. GRB190211A: GROWTH-India detection of optical afterglow

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