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"

32501 results found.

  1. GRB 230427A: Swift-BAT refined analysis
  2. Konus-Wind detection of GRB 230430A
  3. IPN triangulation of GRB 230430A (short)
  4. GRB 230420A: AROMA-N Optical Upper Limit
  5. GRB 230430A: Fermi GBM observation
  6. GRB 230430A: AstroSat CZTI detection
  7. GRB 230427A: NOT optical upper limit
  8. GRB 230427A: TSHAO, SAO RAS, AbAO optical upper limit
  9. GRB 230427A: Swift/UVOT Detection
  10. Duplicate of GCN 33369
  11. GRB 230427A: Gaoyazi/GOT optical upper limit
  12. GRB 230427A: OHP/T193 spectroscopy observations of WISEA J101316.01+481158.7
  13. GRB 230427A: Nanshan/HMT optical upper limit
  14. GRB 230427A: Osservatorio Astronomico Nastro verde upper limit
  15. GRB 230427A: OSIRIS+/GTC observations
  16. GRB 230426A: VZLUSAT-2 detection
  17. GRB 230427A: GIT optical upper limit
  18. GRB 230427A: Bassano Bresciano Observatory upper limit
  19. GRB 230427A: GMG upper limit
  20. GRB 230427A : OHP/T193 optical upper limit
  21. GRB 230423A(trigger #1165354): Swift-BAT refined analysis
  22. GRB 230427A: AKO Upper Limit
  23. GRB 230426A: MASTER OT J023135.16-792104.8 optical counterpart discovery
  24. GRB 230427A: MITSuME Akeno optical upper limits
  25. GRB 230426A: Fermi GBM Detection
  26. GRB 230426A: AstroSat CZTI detection
  27. GRB 230423A: Swift/UVOT Upper Limits
  28. GRB 230420A: Lowell Discovery Telescope Optical Detection
  29. GRB 230423A: Swift-XRT afterglow detection
  30. Erroneous submission
  31. GRB 221009A: Late-time JWST Observations and Detection of Supernova Emission
  32. GRB 230421A: Fermi GBM observation
  33. Konus-Wind detection of GRB 230418A
  34. GRB 230420A: Swift/UVOT Upper Limits
  35. GRB 230421: Swift/BAT-GUANO arcminute localization
  36. GRB230420A: VLT optical observation
  37. GRB 230420A: Swift-BAT refined analysis
  38. Duplicate of GCN 33668
  39. GRB 230420A: MITSuME Akeno optical observation
  40. GRB 230420A: NOT optical afterglow confirmation
  41. GRB 230420A: Gaoyazi/GOT optical upper limit
  42. GRB 230420A: LCOGT Optical Upper Limit
  43. GRB230414B: VIRT Optical Upper Limit
  44. IPN triangulation of GRB 230418A (short)
  45. GRB 230418A: AstroSat CZTI detection
  46. GRB 230402A: Fermi GBM detection
  47. GRB 230418A: Swift/BAT-GUANO detection outside the coded FOV
  48. GRB 230402A: Fermi-LAT detection
  49. Fermi-LAT gamma-ray observations of IceCube-230416A
  50. GRB 230414B: Nickel and KAIT telescope optical observations
  51. Duplicate of GCN 33640
  52. Duplicate of GCN 33640
  53. GRB 230414B Swift-BAT refined analysis
  54. Duplicate of GCN 33642
  55. GRB 230415A: Fermi GBM detection
  56. GRB 230414B: Swift/UVOT Detection
  57. New GCN Circulars Portal for Rapid Communications on Astronomical Transients is Online
  58. VIRT optical transient detection
  59. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  60. GRB 230307A: iTelescope optical upper limit (likely)
  61. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  62. GRB 230414B: Lulin 40cm-SLT optical limit
  63. GRB 230414B: Redshift from OSIRIS/GTC
  64. GRB 230414B: AbAO optical observations
  65. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  66. GRB 230414B: Swift-XRT refined Analysis
  67. GRB 230414B: Dabancheng/GHOST optical observations
  68. GRB 230414B: slow optical light curve decay
  69. GRB 230414B: SAO RAS optical observations
  70. GRB 230414B: 1.3m DFOT Optical observations
  71. Fermi GRB 230414A: Global MASTER-Net observations report
  72. GRB 230414B: GROWTH India Telescope afterglow confirmation
  73. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  74. GRB 230414B: Nanshan/HMT optical afterglow detection
  75. GRB 230414A: Mondy optical afterglow candidate
  76. Swift GRB 230414B: Global MASTER-Net observations report
  77. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  78. GRB 230328B: redshift lower limit estimating
  79. GRB 230409B: Mondy optical upper limit
  80. GRB 230409B: OHP/T193 optical upper limit
  81. GRB 230410B: VZLUSAT-2 detection
  82. Fermi GRB 230409C: Global MASTER-Net observations report
  83. Fermi GRB 230409A: Global MASTER-Net observations report
  84. GRB 230409B: Swift-XRT refined Analysis
  85. GRB 230409B: Swift-BAT refined analysis
  86. Swift GRB 230409B: Global MASTER-Net observations report
  87. GRB 230409B: Swift/UVOT Detection
  88. GRB 230405B: VZLUSAT-2 detection
  89. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  90. Fermi-LAT gamma-ray observations of IceCube-230405A
  91. Konus-Wind detection of GRB 230405B
  92. GRB 230405B: AGILE detection
  93. GRB 230405B: Swift-XRT refined Analysis
  94. GRB 230405B: Fermi GBM Observation
  95. GRB 230405B: MeerLICHT upper limits
  96. GRB 230307A: JWST NIRSpec observations, possible higher redshift
  97. GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
  98. GRB 230307A: good match with kilonova models
  99. GRB 230307A: short mininum variability timescale compatible with a merger origin
  100. GRB 230405B: Swift/UVOT Upper Limits

Advanced

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