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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').
  1. GRB testing
  2. GRB iOS chrome again
  3. grb123: iOS Chrome testing
  4. GRB testing iOS
  5. GRB test from Chrome iOS
  6. GRB testing
  7. GRB Testing for Kafka
  8. GRB Testing
  9. GRB foobar
  10. GRB foobar test
  11. GRB testing 3
  12. GRB testing 2
  13. GRB testing
  14. GRB test 4
  15. GRB test 3
  16. GRB test 2
  17. GRB test
  18. GRB foobar
  19. GRB foobar
  20. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  21. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  22. GRB foobar
  23. GRB foobar
  24. PKS2326-505, millimeter wavelength flare, transient
  25. GRB foo 3
  26. GRB foo 2
  27. GRB foo
  28. GRB foo
  29. GRB foo
  30. GRB foo
  31. GRB test
  32. GRB foo
  33. GRB foobar
  34. GRB foobar
  35. GRB foobar
  36. GRB foobar
  37. GRB foobar
  38. GRB test
  39. MAGIC test
  40. GRB test
  41. GRB foo
  42. Test GCN GW submission
  43. GRB test 2
  44. GRB test
  45. GRB test
  46. Test GW GCN hermes submission 2
  47. Test GW GCN hermes submission
  48. Test GW GCN hermes submission
  49. A GRB test
  50. TEST GW GCN hermes submission
  51. GRB 170817A: an awesome GCN Circular
  52. VIRT optical transient detection
  53. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  54. GRB 230307A: iTelescope optical upper limit (likely)
  55. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  56. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  57. Fermi trigger No 703284533: Global MASTER-Net observations report
  58. GRB 230414B: Lulin 40cm-SLT optical limit
  59. GRB 230414B: Bassano Bresciano Observatory optical observations
  60. GRB 230414B: Redshift from OSIRIS/GTC
  61. GRB 230414B: AbAO optical observations
  62. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  63. GRB 230414B: Swift-XRT refined Analysis
  64. GRB 230414B: Dabancheng/GHOST optical observations
  65. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
  66. GRB 230414B: slow optical light curve decay
  67. GRB 230414B: SAO RAS optical observations
  68. GRB 230414B: Enhanced Swift-XRT position
  69. GRB 230414B: 1.3m DFOT Optical observations
  70. Fermi GRB 230414A: Global MASTER-Net observations report
  71. GRB 230414B: GROWTH India Telescope afterglow confirmation
  72. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  73. GRB 230414B: Nanshan/HMT optical afterglow detection
  74. GRB 230414A: Mondy optical afterglow candidate
  75. Swift GRB 230414B: Global MASTER-Net observations report
  76. GRB 230414B: Prompt enhanced Swift-XRT position
  77. GRB 230414B: Swift detection of a burst
  78. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  79. GRB 230414A: Fermi GBM Final Real-time Localization
  80. GRB 230328B: redshift lower limit estimating
  81. GRB 230409B: Mondy optical upper limit
  82. GRB 230409B: OHP/T193 optical upper limit
  83. GRB 230410B: VZLUSAT-2 detection
  84. GRB 230409D: VZLUSAT-2 detection
  85. GRB 230410B: AGILE detection of a burst
  86. GRB 230410A: Fermi GBM Final Real-time Localization
  87. Fermi GRB 230409C: Global MASTER-Net observations report
  88. Fermi GRB 230409A: Global MASTER-Net observations report
  89. GRB 230409C: Fermi GBM Final Real-time Localization
  90. GRB 230409B: Swift-XRT refined Analysis
  91. GRB 230409B: Swift-BAT refined analysis
  92. Fermi trigger No 702745263: Global MASTER-Net observations report
  93. Swift GRB 230409B: Global MASTER-Net observations report
  94. GRB 230409B: Swift/UVOT Detection
  95. GRB 230409B: Enhanced Swift-XRT position
  96. MAXI GRB230408.82: Global MASTER-Net observations report
  97. GRB 230409B: Swift detection of a burst
  98. GRB 230409A: Fermi GBM Final Real-time Localization
  99. GRB 230405B: VZLUSAT-2 detection
  100. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube

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