Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

28084 results found.

  1. GRB 230512A: Swift-XRT observations
  2. IceCube-230511A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-Cascade 230511A: Upper limits from a search for additional neutrino events in IceCube
  4. GRB 230512A: GIT optical follow-up ZTF candidates
  5. GRB 230512A: Fermi GBM detection
  6. GRB 230512A: Fermi-LAT detection
  7. GRB 230512A: Fermi GBM Final Localization
  8. GRB 230510A: GIT optical upper limits
  9. GRB 230510A: LCOGT Optical Upper Limit
  10. GRB 230510A: Swift/UVOT Observations
  11. GRB 230510B: AstroSat CZTI detection
  12. GRB 230510A: Fermi GBM detection
  13. Fermi trigger No 705446499: Global MASTER-Net observations report
  14. GRB 230510A: Gaoyazi/GOT optical upper limit
  15. GRB 230510A: Nanshan/NEXT optical afterglow detection
  16. GRB 230510B: MAXI/GSC detection
  17. GRB 230506B: Fermi GBM detection
  18. GRB 230510A: Swift-XRT refined Analysis
  19. GRB 230510A: Enhanced Swift-XRT position
  20. GRB 230506C: Fermi GBM detection
  21. GRB 230510A: Swift detection of a burst
  22. GRB 230506C: SAO RAS optical observations
  23. IceCube-230506A: Upper limits from a search for additional neutrino events in IceCube
  24. Fermi-LAT gamma-ray observations of IceCube-230506A
  25. GRB 230506C: Swift-XRT refined Analysis
  26. GRB 230506C: Swift-BAT refined analysis
  27. GRB 230506B: Swift-BAT refined analysis
  28. GRB 230506C: spectro-imaging observations of the optical afterglow with T193-OHP
  29. GRB 230506B: LCOGT Optical Upper Limits
  30. GRB 230506C: Swift/UVOT Upper Limits
  31. GRB 230506C: NUTTelA-TAO / BSTI Early Optical Limits
  32. GRB 230506B: Swift-XRT refined Analysis
  33. GRB 230506C: Swift-XRT analysis
  34. GRB 230506C: TSHAO possible afterglow candidate
  35. GRB 230506B: Swift/UVOT Detection
  36. GRB 230506B: Swift detection of a burst
  37. GRB 230506B: Swift detection of a burst
  38. GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
  39. GRB 230427A: Swift-BAT refined analysis
  40. IceCube-Cascade 230430A: Upper limits from a search for additional neutrino events in IceCube
  41. GRB 230420A: AROMA-N Optical Upper Limit
  42. GRB 230427A: NOT optical upper limit
  43. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  44. GRB 230427A: Swift/UVOT Detection
  45. GRB 230427A: Gaoyazi/GOT optical upper limit
  46. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  47. GRB 230427A: Nanshan/HMT optical upper limit
  48. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  49. GRB 230427A: OSIRIS+/GTC observations
  50. GRB 230427A: Swift-XRT refined Analysis
  51. GRB 230426A: VZLUSAT-2 detection
  52. GRB 230427A: GIT optical upper limit
  53. GRB 230427A: Bassano Bresciano Observatory upper limit
  54. GRB 230427A: GMG upper limit
  55. GRB 230427A : OHP/T193 optical upper limit
  56. GRB 230423A(trigger #1165354): Swift-BAT refined analysis
  57. GRB 230427A: AKO Upper Limit
  58. GRB 230427A: MITSuME Akeno optical upper limits
  59. GRB 230426A: Fermi GBM Detection
  60. GRB 230427A: Enhanced Swift-XRT position
  61. GRB 230427A: Swift detection of a burst with an optical counterpart
  62. Fermi trigger No 704233744: Global MASTER-Net observations report
  63. GRB 230423A: Swift/UVOT Upper Limits
  64. GRB 230423A: Swift-XRT refined Analysis
  65. Swift Trigger 1165354 is probably not a GRB
  66. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  67. GRB 230421A: Fermi GBM observation
  68. GRB 230420A: Swift/UVOT Upper Limits
  69. GRB 230421: Swift/BAT-GUANO arcminute localization
  70. GRB230420A: VLT optical observation
  71. GRB 230420A: Swift-BAT refined analysis
  72. GRB 230420A: Swift-XRT refined Analysis
  73. GRB 230420A: MITSuME Akeno optical observation
  74. GRB 230420A: NOT optical afterglow confirmation
  75. GRB 230420A: Gaoyazi/GOT optical upper limit
  76. GRB 230420A: LCOGT Optical Upper Limit
  77. GRB 230420A: Enhanced Swift-XRT position
  78. GRB230414B: VIRT Optical Upper Limit
  79. IPN triangulation of GRB 230418A (short)
  80. GRB 230420A: Swift detection of a burst
  81. GRB 230402A: Fermi GBM detection
  82. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  83. GRB 230418A: Fermi GBM Observation
  84. IceCube-Cascade 230417A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 230402A: Fermi-LAT detection
  86. Fermi-LAT gamma-ray observations of IceCube-230416A
  87. GRB 230414B: Nickel and KAIT telescope optical observations
  88. GRB 230414B Swift-BAT refined analysis
  89. GRB 230415A: Fermi GBM detection
  90. GRB 230414B: Swift/UVOT Detection
  91. GRB 230414B: Osservatorio Astronomico Nastro Verde - Sorrento: optical observations
  92. IceCube-230416A: Upper limits from a search for additional neutrino events in IceCube
  93. GRB 230415A: Swift/BAT-GUANO detection
  94. VIRT optical transient detection
  95. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  96. GRB 230307A: iTelescope optical upper limit (likely)
  97. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  98. GRB 230414B: Lulin 40cm-SLT optical limit
  99. GRB 230414B: Bassano Bresciano Observatory optical observations
  100. GRB 230414B: AbAO optical observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov