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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"

10772 results found.

  1. GRB 230512A: Kitab possible afterglow candidate
  2. Fermi trigger No 705565670: Global MASTER-Net observations report
  3. Fermi-LAT gamma-ray observations of IceCube-230511A
  4. GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
  5. GRB 230512A: Fermi-LAT detection
  6. GRB 230512A: AstroSat CZTI detection
  7. GRB 230510B: AstroSat CZTI detection
  8. GRB 230510B: MAXI/GSC detection
  9. Fermi trigger No 705413051: Global MASTER-Net observations report
  10. Fermi-LAT gamma-ray observations of IceCube-230506A
  11. GRB 230506C: Swift-XRT refined Analysis
  12. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  13. GRB 230506C: Swift-XRT analysis
  14. GRB 230506B: Swift/UVOT Detection
  15. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  16. GRB 230427A: Swift-BAT refined analysis
  17. GRB 230503A: Fermi GBM Final Real-time Localization
  18. Konus-Wind detection of GRB 230430A
  19. GRB 230420A: AROMA-N Optical Upper Limit
  20. GRB 230430A: AstroSat CZTI detection
  21. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  22. GRB 230427A: Swift-XRT refined Analysis
  23. GRB 230426A: VZLUSAT-2 detection
  24. GRB 230427A: GIT optical upper limit
  25. GRB 230427A : OHP/T193 optical upper limit
  26. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  27. GRB 230426A: Fermi GBM Detection
  28. GRB 230426A: AstroSat CZTI detection
  29. GRB 230426A: Fermi GBM Final Real-time Localization
  30. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  31. Konus-Wind detection of GRB 230418A
  32. GRB 230420A: Swift-XRT refined Analysis
  33. GRB 230420A: MITSuME Akeno optical observation
  34. GRB 230420A: Gaoyazi/GOT optical upper limit
  35. GRB 230420A: BOOTES-5/JGT optical afterglow detection
  36. GRB 230420A: LCOGT Optical Upper Limit
  37. IPN triangulation of GRB 230418A (short)
  38. GRB 230420A: Swift detection of a burst
  39. GRB 230418A: AstroSat CZTI detection
  40. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  41. IceCube-Cascade 230417A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 230402A: Fermi-LAT detection
  43. Fermi-LAT gamma-ray observations of IceCube-230416A
  44. GRB 230415A: Fermi GBM detection
  45. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  46. GRB 230415A: Swift/BAT-GUANO detection
  47. New GCN Circulars Portal for Rapid Communications on Astronomical Transients is Online
  48. GRB 230307A: iTelescope optical upper limit (likely)
  49. GRB 230414B: Swift-XRT refined Analysis
  50. Fermi GRB 230414A: Global MASTER-Net observations report
  51. GRB 230414B: Nanshan/HMT optical afterglow detection
  52. GRB 230414B: Swift detection of a burst
  53. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  54. Fermi GRB 230409C: Global MASTER-Net observations report
  55. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  56. Fermi-LAT gamma-ray observations of IceCube-230405A
  57. Konus-Wind detection of GRB 230405B
  58. GRB 230405B: MeerLICHT upper limits
  59. IceCube Alert 230405.56: Global MASTER-Net observations report
  60. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  61. GRB 230405B: AstroSat CZTI detection
  62. IceCube-230405A: IceCube observation of a high-energy neutrino candidate
  63. GRB 230404A: AstroSat CZTI detection
  64. GRB 230402A: AstroSat CZTI detection
  65. Fermi-LAT gamma-ray observations of IceCube-230401A and detection of Fermi J0030.2+0005
  66. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  67. GRB 230228A: detection by GTC of the potential host galaxy
  68. IceCube-Cascade 230329A: Upper limits from a search for additional neutrino events in IceCube
  69. GRB 230328B: 3.6m DOT multiband optical observation
  70. Fermi trigger No 701883729: Global MASTER-Net observations report
  71. Konus-Wind detection of GRB 230328B
  72. GRB 230328B: Liverpool Telescope afterglow detection
  73. GRB 230328B: OHP/T120 optical observations
  74. GRB 230328B: Swift-XRT refined Analysis
  75. GRB 230328B: AstroSat CZTI detection
  76. GRB 230328B: Mondy, AbAO and Kitab optical observations
  77. GRB 230328B: Swift detection of a burst with an optical afterglow
  78. GRB 230325A: Swift-XRT refined Analysis
  79. GRB 230325A: Swift detection of a burst
  80. GRB 230320B: Fermi GBM Observation
  81. Konus-Wind detection of GRB 230309A
  82. Konus-Wind detection of GRB 230308A
  83. Konus-Wind detection of GRB 230304B
  84. GRB 230322B: Swift-XRT refined Analysis
  85. GRB 230322B: Swift detection of a burst with optical counterpart
  86. GRB 230322A: Fermi GBM Final Real-time Localization
  87. GRB 230320B: GRBAlpha detection
  88. GRB 230320B: CALET Gamma-Ray Burst Monitor detection
  89. Fermi trigger No 701071944: Global MASTER-Net observations report
  90. SGR 1806-20: Correction to GCN 33494
  91. INTEGRAL detection of a burst from SGR 1806-200
  92. GRB 230321B: AstroSat CZTI detection
  93. GRB 230320B: AstroSat CZTI detection
  94. GRB 230320A: Fermi GBM Final Real-time Localization
  95. GRB 230314A: TURBO Optical Upper Limit
  96. Fermi trigger No 700976129: Global MASTER-Net observations report
  97. IPN triangulation of GRB 230309A
  98. Fermi GRB 230316A: Global MASTER-Net observations report
  99. GRB 230304D: AstroSat CZTI detection
  100. GRB 230313A: AstroSat CZTI detection

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