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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"
  1. GW Test GCN circular submission still works
  2. GRB test
  3. GRB 250115: A GRB during the coffee break at AAS
  4. GRB test from AAS
  5. GRB test
  6. GRB 000001Q TEST
  7. GRB 123456Z courey testing
  8. GRB Test
  9. GRB testing
  10. GRB iOS chrome again
  11. grb123: iOS Chrome testing
  12. GRB testing iOS
  13. GRB test from Chrome iOS
  14. GRB testing
  15. GRB Testing for Kafka
  16. GRB Testing
  17. GRB foobar
  18. GRB foobar test
  19. GRB testing 3
  20. GRB testing 2
  21. GRB testing
  22. GRB test 4
  23. GRB test 3
  24. GRB test 2
  25. GRB test
  26. GRB foobar
  27. GRB foobar
  28. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  29. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  30. GRB foobar
  31. GRB foobar
  32. PKS2326-505, millimeter wavelength flare, transient
  33. GRB foo 3
  34. GRB foo 2
  35. GRB foo
  36. GRB foo
  37. GRB foo
  38. GRB foo
  39. GRB test
  40. GRB foo
  41. GRB foobar
  42. GRB foobar
  43. GRB foobar
  44. GRB foobar
  45. GRB foobar
  46. GRB test
  47. MAGIC test
  48. GRB test
  49. GRB foo
  50. Test GCN GW submission
  51. GRB test 2
  52. GRB test
  53. GRB test
  54. Test GW GCN hermes submission 2
  55. Test GW GCN hermes submission
  56. Test GW GCN hermes submission
  57. A GRB test
  58. TEST GW GCN hermes submission
  59. GRB 170817A: an awesome GCN Circular
  60. VIRT optical transient detection
  61. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  62. GRB 230307A: iTelescope optical upper limit (likely)
  63. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  64. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  65. Fermi trigger No 703284533: Global MASTER-Net observations report
  66. GRB 230414B: Lulin 40cm-SLT optical limit
  67. GRB 230414B: Bassano Bresciano Observatory optical observations
  68. GRB 230414B: Redshift from OSIRIS/GTC
  69. GRB 230414B: AbAO optical observations
  70. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  71. GRB 230414B: Swift-XRT refined Analysis
  72. GRB 230414B: Dabancheng/GHOST optical observations
  73. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
  74. GRB 230414B: slow optical light curve decay
  75. GRB 230414B: SAO RAS optical observations
  76. GRB 230414B: Enhanced Swift-XRT position
  77. GRB 230414B: 1.3m DFOT Optical observations
  78. Fermi GRB 230414A: Global MASTER-Net observations report
  79. GRB 230414B: GROWTH India Telescope afterglow confirmation
  80. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  81. GRB 230414B: Nanshan/HMT optical afterglow detection
  82. GRB 230414A: Mondy optical afterglow candidate
  83. Swift GRB 230414B: Global MASTER-Net observations report
  84. GRB 230414B: Prompt enhanced Swift-XRT position
  85. GRB 230414B: Swift detection of a burst
  86. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  87. GRB 230414A: Fermi GBM Final Real-time Localization
  88. GRB 230328B: redshift lower limit estimating
  89. GRB 230409B: Mondy optical upper limit
  90. GRB 230409B: OHP/T193 optical upper limit
  91. GRB 230410B: VZLUSAT-2 detection
  92. GRB 230409D: VZLUSAT-2 detection
  93. GRB 230410B: AGILE detection of a burst
  94. GRB 230410A: Fermi GBM Final Real-time Localization
  95. Fermi GRB 230409C: Global MASTER-Net observations report
  96. Fermi GRB 230409A: Global MASTER-Net observations report
  97. GRB 230409C: Fermi GBM Final Real-time Localization
  98. GRB 230409B: Swift-XRT refined Analysis
  99. GRB 230409B: Swift-BAT refined analysis
  100. Fermi trigger No 702745263: Global MASTER-Net observations report

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Download all Circulars as a .tar.gz archive:
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