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

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