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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"

35982 results found.

  1. GRB 230405B: Prompt enhanced Swift-XRT position
  2. GRB 230405B: Swift detection of a burst
  3. GRB 230405B: Fermi GBM Final Real-time Localization
  4. GRB 230307A: JWST observations consistent with the presence of a kilonova
  5. Fermi GRB 230405A: Global MASTER-Net observations report
  6. GRB 230405A: Fermi GBM Final Real-time Localization
  7. GRB 230404A: AstroSat CZTI detection
  8. GRB 230404A: Fermi GBM Final Real-time Localization
  9. GRB 230402A: CALET Gamma-Ray Burst Monitor detection
  10. GRB 230402A: AstroSat CZTI detection
  11. GRB 230328B: Multa observatory optical afterglow observation
  12. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  13. GRB 230228A: detection by GTC of the potential host galaxy
  14. GRB 230328B: Swift/UVOT Detection
  15. GRB 230402A: AGILE detection
  16. Fermi GRB 230402A: Global MASTER-Net observations report
  17. GRB 230402A: Fermi GBM Final Real-time Localization
  18. GRB 230307A: Bad Time Intervals for Fermi GBM data
  19. GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
  20. GRB 230328B: CAHA 2.2m/CAFOS detection
  21. GRB 230328B: 3.6m DOT multiband optical observation
  22. GRB 230330B: Fermi GBM Final Localization
  23. Konus-Wind detection of GRB 230328B
  24. GRB 230328B: GRBAlpha detection
  25. GRB 230330A: Fermi GBM Final Real-time Localization
  26. GRB 230328B: Swift-BAT refined analysis
  27. GRB 230328B: Nanshan/NEXT 2nd optical observation
  28. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  29. GRB 230328B: Liverpool Telescope afterglow detection
  30. GRB 230328B: OHP/T120 optical observations
  31. GRB 230328B: GIT optical follow-up
  32. GRB 230328B: OASDG optical observations
  33. GRB 230328B: Nanshan/NEXT optical upper limit
  34. GRB 230328B: Swift-XRT refined Analysis
  35. GRB 230328B: AstroSat CZTI detection
  36. GRB 230328B: Fermi GBM observation
  37. GRB 230328B: Mondy, AbAO and Kitab optical observations
  38. GRB 230328B: Enhanced Swift-XRT position
  39. GRB 230328B: Mondy optical afterglow confirmation
  40. GRB 230328B: Swift detection of a burst with an optical afterglow
  41. GRB 230328B: Fermi GBM Final Real-time Localization
  42. Fermi GRB 230328A: Global MASTER-Net observations report
  43. GRB 230328A: Fermi GBM Final Real-time Localization
  44. GRB 230325A: Swift-BAT refined analysis
  45. GRB 230325A: Swift/UVOT Upper Limits
  46. GRB 230325A: X-shooter optical afterglow and redshift
  47. GRB 230325A: Swift-XRT refined Analysis
  48. GRB 230322B: Swift-BAT refined analysis
  49. GRB 230325A: Enhanced Swift-XRT position
  50. GRB 230325A: Prompt enhanced Swift-XRT position
  51. GRB 230325A: Swift detection of a burst
  52. GRB 230320B: Fermi GBM Observation
  53. GRB 230322B: Swift/UVOT Detection
  54. Konus-Wind detection of GRB 230309A
  55. Konus-Wind detection of GRB 230308A
  56. Konus-Wind detection of GRB 230304B
  57. GRB 230322B: Swift-XRT refined Analysis
  58. GRB 230322B: Enhanced Swift-XRT position
  59. Swift GRB 230322B: Global MASTER-Net observations report
  60. GRB 230322B: Swift detection of a burst with optical counterpart
  61. GRB 230322A: Fermi GBM Final Real-time Localization
  62. GRB 230320B: GRBAlpha detection
  63. GRB 230321A: CALET Gamma-Ray Burst Monitor detection
  64. GRB 230320B: CALET Gamma-Ray Burst Monitor detection
  65. GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
  66. Fermi GRB 230320A: Global MASTER-Net observations report
  67. Fermi GRB 230321A: Global MASTER-Net observations report
  68. GRB 230321B: AstroSat CZTI detection
  69. GRB 230320B: AstroSat CZTI detection
  70. GRB 230321A: BALROG localization (Fermi Trigger 701065308 / GRB 230321182)
  71. GRB 230321A: Fermi GBM Final Real-time Localization
  72. GRB 230320A: Fermi GBM Final Real-time Localization
  73. GRB 230314A: TURBO Optical Upper Limit
  74. GRB 230307A: Continued Gemini-South observations confirm rapid optical fading
  75. IPN triangulation of GRB 230309A
  76. Fermi GRB 230316A: Global MASTER-Net observations report
  77. GRB 230304D: AstroSat CZTI detection
  78. GRB 230316A: Fermi GBM Final Real-time Localization
  79. IPN triangulation of GRB 230304B
  80. GRB 230313A: AstroSat CZTI detection
  81. GRB 230307A: Far off-axis NuSTAR detection of the GRB
  82. IPN triangulation of GRB 230308A (short/bright)
  83. Fermi GRB 230314A: Global MASTER-Net observations report
  84. GRB 230307A: ATCA radio detection
  85. GRB 230314A: Fermi GBM Final Real-time Localization
  86. VZLUSAT-2 detection of SGR 1806-20
  87. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  88. GRB 230307A: Swift/UVOT detection
  89. GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
  90. Fermi GRB 230313A: Global MASTER-Net observations report
  91. GRB 230313A: Fermi GBM Final Real-time Localization
  92. GRB 230307A: soft X-ray detection with LEIA
  93. GRB 230307A: Swift-XRT afterglow detection
  94. GRB 230309A: AstroSat CZTI detection of a bright long GRB
  95. Further improved IPN localization for GRB 230307A
  96. GRB 230307A: SOAR/Goodman detection of the possible host galaxy
  97. GRB 230308A: CALET Gamma-Ray Burst Monitor detection
  98. GRB 230310A: AstroSat CZTI detection
  99. GRB 230307A: GECKO optical observations and detections of the afterglow
  100. GRB 230307A: MAXI/GSC upper limit

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