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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"

28091 results found.

  1. IPN triangulation of GRB 230512A
  2. GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
  3. GRB 230512A: GIT non detection of afterglow candidate
  4. GRB 230512A: Kitab possible afterglow candidate
  5. Fermi trigger No 705565670: Global MASTER-Net observations report
  6. Fermi-LAT gamma-ray observations of IceCube-230511A
  7. GRB 230510A: OHP/T193 and OHP/T120 optical observations
  8. GRB 230512A: Swift-XRT observations
  9. IceCube-230511A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 230512A: GIT optical follow-up ZTF candidates
  12. GRB 230512A: Fermi GBM detection
  13. GRB 230512A: Fermi-LAT detection
  14. GRB 230512A: Fermi GBM Final Localization
  15. GRB 230510A: GIT optical upper limits
  16. GRB 230510A: LCOGT Optical Upper Limit
  17. GRB 230510A: Swift/UVOT Observations
  18. GRB 230510B: AstroSat CZTI detection
  19. GRB 230510A: Fermi GBM detection
  20. Fermi trigger No 705446499: Global MASTER-Net observations report
  21. GRB 230510A: Gaoyazi/GOT optical upper limit
  22. GRB 230510A: Nanshan/NEXT optical afterglow detection
  23. GRB 230510B: MAXI/GSC detection
  24. GRB 230506B: Fermi GBM detection
  25. GRB 230510A: Swift-XRT refined Analysis
  26. GRB 230510A: Enhanced Swift-XRT position
  27. GRB 230506C: Fermi GBM detection
  28. GRB 230510A: Swift detection of a burst
  29. GRB 230506C: SAO RAS optical observations
  30. IceCube-230506A: Upper limits from a search for additional neutrino events in IceCube
  31. Fermi-LAT gamma-ray observations of IceCube-230506A
  32. GRB 230506C: Swift-XRT refined Analysis
  33. GRB 230506C: Swift-BAT refined analysis
  34. GRB 230506B: Swift-BAT refined analysis
  35. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  36. GRB 230506B: LCOGT Optical Upper Limits
  37. GRB 230506C: Swift/UVOT Upper Limits
  38. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  39. GRB 230506B: Swift-XRT refined Analysis
  40. GRB 230506C: Swift-XRT analysis
  41. GRB 230506C: TSHAO possible afterglow candidate
  42. GRB 230506B: Swift/UVOT Detection
  43. GRB 230506B: Swift detection of a burst
  44. GRB 230506B: Swift detection of a burst
  45. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  46. GRB 230427A: Swift-BAT refined analysis
  47. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  48. GRB 230420A: AROMA-N Optical Upper Limit
  49. GRB 230427A: NOT optical upper limit
  50. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  51. GRB 230427A: Swift/UVOT Detection
  52. GRB 230427A: Gaoyazi/GOT optical upper limit
  53. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  54. GRB 230427A: Nanshan/HMT optical upper limit
  55. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  56. GRB 230427A: OSIRIS+/GTC observations
  57. GRB 230427A: Swift-XRT refined Analysis
  58. GRB 230426A: VZLUSAT-2 detection
  59. GRB 230427A: GIT optical upper limit
  60. GRB 230427A: Bassano Bresciano Observatory upper limit
  61. GRB 230427A: GMG upper limit
  62. GRB 230427A : OHP/T193 optical upper limit
  63. GRB 230423A(trigger #1165354): Swift-BAT refined analysis
  64. GRB 230427A: AKO Upper Limit
  65. GRB 230427A: MITSuME Akeno optical upper limits
  66. GRB 230426A: Fermi GBM Detection
  67. GRB 230427A: Enhanced Swift-XRT position
  68. GRB 230427A: Swift detection of a burst with an optical counterpart
  69. Fermi trigger No 704233744: Global MASTER-Net observations report
  70. GRB 230423A: Swift/UVOT Upper Limits
  71. GRB 230423A: Swift-XRT refined Analysis
  72. Swift Trigger 1165354 is probably not a GRB
  73. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  74. GRB 230421A: Fermi GBM observation
  75. GRB 230420A: Swift/UVOT Upper Limits
  76. GRB 230421: Swift/BAT-GUANO arcminute localization
  77. GRB230420A: VLT optical observation
  78. GRB 230420A: Swift-BAT refined analysis
  79. GRB 230420A: Swift-XRT refined Analysis
  80. GRB 230420A: MITSuME Akeno optical observation
  81. GRB 230420A: NOT optical afterglow confirmation
  82. GRB 230420A: Gaoyazi/GOT optical upper limit
  83. GRB 230420A: LCOGT Optical Upper Limit
  84. GRB 230420A: Enhanced Swift-XRT position
  85. GRB230414B: VIRT Optical Upper Limit
  86. IPN triangulation of GRB 230418A (short)
  87. GRB 230420A: Swift detection of a burst
  88. GRB 230402A: Fermi GBM detection
  89. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  90. GRB 230418A: Fermi GBM Observation
  91. IceCube-Cascade 230417A: Upper limits from a search for additional neutrino events in IceCube
  92. GRB 230402A: Fermi-LAT detection
  93. Fermi-LAT gamma-ray observations of IceCube-230416A
  94. GRB 230414B: Nickel and KAIT telescope optical observations
  95. GRB 230414B Swift-BAT refined analysis
  96. GRB 230415A: Fermi GBM detection
  97. GRB 230414B: Swift/UVOT Detection
  98. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  99. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 230415A: Swift/BAT-GUANO detection

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