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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"

35947 results found.

  1. GRB 230510B: AstroSat CZTI detection
  2. GRB 230511C: Fermi GBM Final Localization
  3. GRB 230511B: Fermi GBM Final Real-time Localization
  4. GRB 230511A: Fermi GBM Final Real-time Localization
  5. GRB 230510A: Fermi GBM detection
  6. GRB 230510A: Gaoyazi/GOT optical upper limit
  7. GRB 230510B: CALET Gamma-Ray Burst Monitor detection
  8. GRB 230510A: CALET Gamma-Ray Burst Monitor detection
  9. GRB 230510A: Nanshan/NEXT optical afterglow detection
  10. GRB 230510B: MAXI/GSC detection
  11. GRB 230510B: Fermi GBM Final Real-time Localization
  12. GRB 230506B: Fermi GBM detection
  13. GRB 230510A: Swift-XRT refined Analysis
  14. GRB 230510A: Enhanced Swift-XRT position
  15. GRB 230506C: Fermi GBM detection
  16. Fermi Gamma-ray Burst Monitor trigger 230510133/705381054 is not a GRB
  17. GRB 230510A: Swift detection of a burst
  18. GRB 230510A: Fermi GBM Final Real-time Localization
  19. GRB 230506B: Swift/UVOT further analysis
  20. GRB 230506C: T193-OHP MISTRAL tentative redshift
  21. GRB 230506C: SAO RAS optical observations
  22. GRB 230307A: JWST second-epoch observations
  23. GRB 230506C: Swift-XRT refined Analysis
  24. GRB 230506C: Swift-BAT refined analysis
  25. GRB 230506B: Swift-BAT refined analysis
  26. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  27. GRB 230506B: LCOGT Optical Upper Limits
  28. GRB 230506C: Swift/UVOT Upper Limits
  29. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  30. GRB 230506B: Swift-XRT refined Analysis
  31. GRB 230506C: Swift-XRT analysis
  32. GRB 230506C: Candidate afterglow observation by D50
  33. GRB 230506C: TSHAO possible afterglow candidate
  34. GRB 230506B: Swift/UVOT Detection
  35. GRB 230506C: Swift detection of a burst
  36. GRB 230506B: Swift detection of a burst
  37. GRB 230506B: MASTER optical observations
  38. GRB 230506B: Swift detection of a burst
  39. GRB 230506A: Fermi GBM Final Real-time Localization
  40. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  41. GRB 230430A: A short GRB from a neutron star merger
  42. GRB 230427A: Swift-BAT refined analysis
  43. GRB 230503A: Fermi GBM Final Real-time Localization
  44. Konus-Wind detection of GRB 230430A
  45. IPN triangulation of GRB 230430A (short)
  46. GRB 230420A: AROMA-N Optical Upper Limit
  47. GRB 230430B: Fermi GBM Final Localization
  48. GRB 230430A: Fermi GBM observation
  49. GRB 230430A: AstroSat CZTI detection
  50. GRB 230430A: Fermi GBM Final Real-time Localization
  51. GRB 230427A: NOT optical upper limit
  52. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  53. GRB 230427A: Swift/UVOT Detection
  54. GRB 230427A: Gaoyazi/GOT optical upper limit
  55. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  56. GRB 230427A: Nanshan/HMT optical upper limit
  57. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  58. GRB 230427A: OSIRIS+/GTC observations
  59. GRB 230427A: Swift-XRT refined Analysis
  60. GRB 230426A: VZLUSAT-2 detection
  61. GRB 230428A: Fermi GBM Final Real-time Localization
  62. GRB 230427A: GIT optical upper limit
  63. GRB 230427A: Bassano Bresciano Observatory upper limit
  64. GRB 230427A: GMG upper limit
  65. GRB 230427A : OHP/T193 optical upper limit
  66. GRB 230427A: BOOTES-5/JGT afterglow detection
  67. GRB 230423A(trigger #1165354): Swift-BAT refined analysis
  68. GRB 230427A: AKO Upper Limit
  69. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  70. GRB 230427A: MITSuME Akeno optical upper limits
  71. GRB 230426A: Fermi GBM Detection
  72. GRB 230427A: Enhanced Swift-XRT position
  73. GRB 230427A: Swift detection of a burst with an optical counterpart
  74. GRB 230426A: AstroSat CZTI detection
  75. GRB 230426A: Fermi GBM Final Real-time Localization
  76. GRB 230423A: Swift/UVOT Upper Limits
  77. GRB 230425A: Fermi GBM Final Real-time Localization
  78. GRB 230423A: Swift-XRT refined Analysis
  79. GRB 230420A: Lowell Discovery Telescope Optical Detection
  80. GRB 230423A: Swift-XRT afterglow detection
  81. Swift Trigger 1165354 is probably not a GRB
  82. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  83. GRB 230421A: Fermi GBM observation
  84. Konus-Wind detection of GRB 230418A
  85. GRB 230420A: Swift/UVOT Upper Limits
  86. GRB 230421: Swift/BAT-GUANO arcminute localization
  87. GRB230420A: VLT optical observation
  88. GRB 230420A: Swift-BAT refined analysis
  89. GRB 230421A: Fermi GBM Final Real-time Localization
  90. GRB 230420A: Swift-XRT refined Analysis
  91. GRB 230420A: MITSuME Akeno optical observation
  92. GRB 230420A: NOT optical afterglow confirmation
  93. GRB 230420A: Gaoyazi/GOT optical upper limit
  94. GRB 230420A: BOOTES-5/JGT optical afterglow detection
  95. GRB 230420A: LCOGT Optical Upper Limit
  96. GRB 230420A: Enhanced Swift-XRT position
  97. IPN triangulation of GRB 230418A (short)
  98. GRB 230420A: Swift detection of a burst
  99. GRB 230418A: AstroSat CZTI detection
  100. GRB 230418A: AGILE detection

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