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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"

11528 results found.

  1. GRB 200907C: Fermi GBM Final Real-time Localization
  2. Fermi GRB 200906A: Global MASTER-Net observations report
  3. GRB 200906A: EMIR/GTC NIR upper limit
  4. GRB 200906A: OSN 1.5m Upper Limit
  5. GRB 200906A: Fermi GBM detection
  6. GRB 200906A: Fermi GBM Final Real-time Localization
  7. Fermi GRB 200904A: Global MASTER-Net observations report
  8. GRB 200904A: Fermi GBM Final Real-time Localization
  9. Fermi GRB 200903C: Global MASTER-Net observations report
  10. GRB 200903A: Fermi GBM detection
  11. GRB 200903C: Fermi GBM Final Real-time Localization
  12. GRB 200903B: Insight-HXMT/HE detection
  13. AGILE detection of a burst (AGILE trigger no. 526185273)
  14. Fermi GRB 200903B: Global MASTER-Net observations report
  15. GRB 200903B: Fermi GBM Final Real-time Localization
  16. GRB 200903A: Fermi GBM Final Real-time Localization
  17. GRB 200901A: Fermi GBM observation
  18. Fermi GBM trigger 620564765/200831463 is not a GRB
  19. Fermi GRB 200830A: Global MASTER-Net observations report
  20. GRB 200829A: Fermi GBM detection
  21. GRB 200830A: BALROG localization (Fermi Trigger 620474063 / GRB 200830413)
  22. GRB 200830A: Fermi GBM Final Real-time Localization
  23. GRB 200826A: Lowell Discovery Telescope observations of ZTF20abwysqy
  24. Fermi trigger No 620402299: Global MASTER-Net observations report
  25. GRB 200826A: Kitab optical observations
  26. Zwicky Transient Facility discovery of ZTF20abtxwfx/AT2020sev, a fast optical transient and candidate afterglow
  27. Konus-Wind detection of GRB 200826B
  28. IPN triangulation of GRB 200826B
  29. GRB 200826A: VLA Detection at 6 GHz
  30. GRB 200826A: Swift-XRT afterglow detection
  31. GRB 200824A: Insight-HXMT/HE detection
  32. GRB 200826B: Fermi GBM detection
  33. Fermi GRB 200826B: Global MASTER-Net observations report
  34. Fermi GRB 200824A: Global MASTER-Net observations report
  35. GRB200826A: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi Short GRB (Trigger 620108997)
  36. Konus-Wind detection of GRB 200826A
  37. GRB200826A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 620108997)
  38. GRB 200826B: Fermi GBM Final Real-time Localization
  39. IPN triangulation of GRB 200826A (short/bright)
  40. GRB 200826A: Tiled Swift observations
  41. GRB 200826A: AGILE detection
  42. GRB 200826A: AstroSat CZTI detection
  43. GRB 200826A: Fermi GBM observation
  44. GRB 200826A: BALROG localization (Fermi Trigger 620108997 / GRB 200826187)
  45. Fermi GRB 200826A: Global MASTER-Net observations report
  46. GRB 200826A: Fermi GBM Final Real-time Localization
  47. GRB 200824A: Fermi GBM Final Real-time Localization
  48. Konus-Wind observation of GRB 200815A
  49. IPN triangulation of GRB 200815A (short)
  50. GRB 200818A: Fermi GBM Final Localization
  51. Fermi trigger No 619487843: Global MASTER-Net observations report
  52. Fermi GRB 200817A: Global MASTER-Net observations report
  53. GRB 200817A: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 619270776: Global MASTER-Net observations report
  55. GRB 200811A: Fermi GBM Final Real-time Localization
  56. GRB 200811A: BALROG localization (Fermi Trigger 618851447 / GRB 200811632)
  57. GRB 200809B: Fermi GBM detection
  58. Fermi GRB 200809B: Global MASTER-Net observations report
  59. GRB 200809B: BOOTES-3/YA optical upper limit
  60. GRB 200809B: Swift-XRT afterglow detection
  61. GRB 200809B: MAXI/GSC detection
  62. GRB 200809B: AstroSat CZTI detection
  63. GRB 200809B: Swift/BAT-GUANO detection and arcminute localization
  64. GRB 200809B: Fermi GBM Final Real-time Localization
  65. GRB 200808A: AGILE detection
  66. Fermi trigger No 618642276: Global MASTER-Net observations report
  67. GRB 200809A: Fermi GBM Final Real-time Localization
  68. Fermi GRB 200808A: Global MASTER-Net observations report
  69. GRB 200808A: Fermi GBM Final Real-time Localization
  70. GRB 200803A: Chilescope optical upper limit
  71. Fermi-LAT Gamma-ray Observations of IceCube-200806A
  72. IceCube-200806A: Upper limits from Fermi-GBM Observations
  73. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  74. GRB 200803B: MASTER possibly OT discovery
  75. GRB 200803A: AstroSat CZTI detection
  76. GRB 200803A: Fermi GBM detection
  77. GRB 200803A: Swift-XRT afterglow detection
  78. Fermi GRB 200803B: Global MASTER-Net observations report
  79. GRB 200803A: Fermi-LAT detection
  80. GRB 200803A: MASTER optical counterpart discovery
  81. GRB 200803B: Fermi GBM Final Real-time Localization
  82. GRB 200803A: Tiled Swift observations
  83. Fermi GRB 200803A: Global MASTER-Net observations report
  84. GRB 200801B: AstroSat CZTI detection
  85. GRB 200803A: Fermi GBM Final Real-time Localization
  86. Fermi GRB 200801B: Global MASTER-Net observations report
  87. Fermi GRB 200802A: Global MASTER-Net observations report
  88. Konus-Wind detection of GRB 200729A
  89. GRB 200802A: BALROG localization (Fermi Trigger 618061611 / GRB 200802491)
  90. GRB 200802A: Fermi GBM Final Real-time Localization
  91. Fermi GRB 200801A: Global MASTER-Net observations report
  92. Swift Detection of an SGR-like flare from AX J1846.4-0258
  93. GRB 200801B: BALROG localization (Fermi Trigger 617988951 / GRB 200801650)
  94. GRB 200801B: Fermi GBM Final Real-time Localization
  95. GRB 200801A: Fermi GBM Final Real-time Localization
  96. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  97. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  98. GRB 200723A: Swift ToO observations
  99. GRB 200723A: GOTO candidate afterglow and host galaxy
  100. GRB 200724A: Fermi GBM Final Real-time Localization

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