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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 foobar
  2. GRB foobar
  3. GRB testing 3
  4. GRB testing 2
  5. GRB testing
  6. GRB test 4
  7. GRB test 3
  8. GRB test 2
  9. GRB test
  10. GRB foobar
  11. GRB foobar
  12. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  13. LIGO/Virgo/KAGRA S230627c: Zwicky Transient Facility observations and candidates
  14. GRB foobar
  15. GRB foobar
  16. PKS2326-505, millimeter wavelength flare, transient
  17. GRB foo 3
  18. GRB foo 2
  19. GRB foo
  20. GRB foo
  21. GRB foo
  22. GRB foo
  23. GRB test
  24. GRB foo
  25. GRB foobar
  26. GRB foobar
  27. GRB foobar
  28. GRB foobar
  29. GRB foobar
  30. GRB test
  31. MAGIC test
  32. GRB test
  33. GRB foo
  34. Test GCN GW submission
  35. GRB test 2
  36. GRB test
  37. GRB test
  38. Test GW GCN hermes submission 2
  39. Test GW GCN hermes submission
  40. Test GW GCN hermes submission
  41. A GRB test
  42. TEST GW GCN hermes submission
  43. GRB 170817A: an awesome GCN Circular
  44. VIRT optical transient detection
  45. GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs
  46. GRB 230307A: iTelescope optical upper limit (likely)
  47. GRB 230414B: Montarrenti Observatory late time optical afterglow detection
  48. IceCube-230416A: IceCube observation of a high-energy neutrino candidate
  49. Fermi trigger No 703284533: Global MASTER-Net observations report
  50. GRB 230414B: Lulin 40cm-SLT optical limit
  51. GRB 230414B: Bassano Bresciano Observatory optical observations
  52. GRB 230414B: Redshift from OSIRIS/GTC
  53. GRB 230414B: AbAO optical observations
  54. GRB 230409B: 3.6m DOT near-infrared detection, afterglow confirmation
  55. GRB 230414B: Swift-XRT refined Analysis
  56. GRB 230414B: Dabancheng/GHOST optical observations
  57. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-230414A
  58. GRB 230414B: slow optical light curve decay
  59. GRB 230414B: SAO RAS optical observations
  60. GRB 230414B: Enhanced Swift-XRT position
  61. GRB 230414B: 1.3m DFOT Optical observations
  62. Fermi GRB 230414A: Global MASTER-Net observations report
  63. GRB 230414B: GROWTH India Telescope afterglow confirmation
  64. GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
  65. GRB 230414B: Nanshan/HMT optical afterglow detection
  66. GRB 230414A: Mondy optical afterglow candidate
  67. Swift GRB 230414B: Global MASTER-Net observations report
  68. GRB 230414B: Prompt enhanced Swift-XRT position
  69. GRB 230414B: Swift detection of a burst
  70. IceCube-230405A: BOOTES-4/MET Optical Upper Limits
  71. GRB 230414A: Fermi GBM Final Real-time Localization
  72. GRB 230328B: redshift lower limit estimating
  73. GRB 230409B: Mondy optical upper limit
  74. GRB 230409B: OHP/T193 optical upper limit
  75. GRB 230410B: VZLUSAT-2 detection
  76. GRB 230409D: VZLUSAT-2 detection
  77. GRB 230410B: AGILE detection of a burst
  78. GRB 230410A: Fermi GBM Final Real-time Localization
  79. Fermi GRB 230409C: Global MASTER-Net observations report
  80. Fermi GRB 230409A: Global MASTER-Net observations report
  81. GRB 230409C: Fermi GBM Final Real-time Localization
  82. GRB 230409B: Swift-XRT refined Analysis
  83. GRB 230409B: Swift-BAT refined analysis
  84. Fermi trigger No 702745263: Global MASTER-Net observations report
  85. Swift GRB 230409B: Global MASTER-Net observations report
  86. GRB 230409B: Swift/UVOT Detection
  87. GRB 230409B: Enhanced Swift-XRT position
  88. MAXI GRB230408.82: Global MASTER-Net observations report
  89. GRB 230409B: Swift detection of a burst
  90. GRB 230409A: Fermi GBM Final Real-time Localization
  91. GRB 230405B: VZLUSAT-2 detection
  92. IceCube-230405A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi-LAT gamma-ray observations of IceCube-230405A
  94. Konus-Wind detection of GRB 230405B
  95. GRB 230405B: AGILE detection
  96. GRB 230405B: Swift-XRT refined Analysis
  97. GRB 230405B: Fermi GBM Observation
  98. GRB 230405B: MeerLICHT upper limits
  99. IceCube Alert 230405.56: Global MASTER-Net observations report
  100. GRB 230307A: JWST NIRSpec observations, possible higher redshift

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