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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. GRB test: this is a test
  2. [TEST] Super-Kamiokande finds a supernova in the Milky Way Galaxy
  3. GW test test test
  4. GW test test test
  5. GW Test GCN circular submission still works
  6. GRB test
  7. GRB 250115: A GRB during the coffee break at AAS
  8. GRB test from AAS
  9. GRB test
  10. GRB 000000A Testing - Have a good day!
  11. GRB 123456Z courey testing
  12. GRB Test
  13. GRB testing
  14. GRB iOS chrome again
  15. grb123: iOS Chrome testing
  16. GRB testing iOS
  17. GRB test from Chrome iOS
  18. GRB testing
  19. GRB Testing for Kafka
  20. GRB Testing
  21. GRB foobar
  22. GRB foobar test
  23. GRB testing 3
  24. GRB testing 2
  25. GRB testing
  26. GRB test 4
  27. GRB test 3
  28. GRB test 2
  29. GRB test
  30. GRB foobar
  31. GRB foobar
  32. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  33. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  34. GRB foobar
  35. GRB foobar
  36. PKS2326-505, millimeter wavelength flare, transient
  37. GRB foo 3
  38. GRB foo 2
  39. GRB foo
  40. GRB foo
  41. GRB foo
  42. GRB foo
  43. GRB test
  44. GRB foo
  45. GRB foobar
  46. GRB foobar
  47. GRB foobar
  48. GRB foobar
  49. GRB foobar
  50. GRB test
  51. MAGIC test
  52. GRB test
  53. GRB foo
  54. Test GCN GW submission
  55. GRB test 2
  56. GRB test
  57. GRB test
  58. Test GW GCN hermes submission 2
  59. Test GW GCN hermes submission
  60. Test GW GCN hermes submission
  61. A GRB test
  62. TEST GW GCN hermes submission
  63. GRB 170817A: an awesome GCN Circular
  64. VIRT optical transient detection
  65. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  66. GRB 230307A: iTelescope optical upper limit (likely)
  67. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  68. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  69. Fermi trigger No 703284533: Global MASTER-Net observations report
  70. GRB 230414B: Lulin 40cm-SLT optical limit
  71. GRB 230414B: Bassano Bresciano Observatory optical observations
  72. GRB 230414B: Redshift from OSIRIS/GTC
  73. GRB 230414B: AbAO optical observations
  74. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  75. GRB 230414B: Swift-XRT refined Analysis
  76. GRB 230414B: Dabancheng/GHOST optical observations
  77. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
  78. GRB 230414B: slow optical light curve decay
  79. GRB 230414B: SAO RAS optical observations
  80. GRB 230414B: Enhanced Swift-XRT position
  81. GRB 230414B: 1.3m DFOT Optical observations
  82. Fermi GRB 230414A: Global MASTER-Net observations report
  83. GRB 230414B: GROWTH India Telescope afterglow confirmation
  84. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  85. GRB 230414B: Nanshan/HMT optical afterglow detection
  86. GRB 230414A: Mondy optical afterglow candidate
  87. Swift GRB 230414B: Global MASTER-Net observations report
  88. GRB 230414B: Prompt enhanced Swift-XRT position
  89. GRB 230414B: Swift detection of a burst
  90. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  91. GRB 230414A: Fermi GBM Final Real-time Localization
  92. GRB 230328B: redshift lower limit estimating
  93. GRB 230409B: Mondy optical upper limit
  94. GRB 230409B: OHP/T193 optical upper limit
  95. GRB 230410B: VZLUSAT-2 detection
  96. GRB 230409D: VZLUSAT-2 detection
  97. GRB 230410B: AGILE detection of a burst
  98. GRB 230410A: Fermi GBM Final Real-time Localization
  99. Fermi GRB 230409C: Global MASTER-Net observations report
  100. Fermi GRB 230409A: Global MASTER-Net observations report

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Download all Circulars as a .tar.gz archive:
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