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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. Fermi trigger No 583567803 Global MASTER-Net observations report
  2. GRB Swift Trigger 912102: KAIT Optical Afterglow Candidate
  3. Swift Trigger 912102: possible GRB 190630B
  4. GRB 190630A: Fermi GBM Final Real-time Localization
  5. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  6. IceCube-190629A - IceCube observation of a high-energy neutrino candidate event
  7. Baksan Neutrino Observatory Alert 190629.56 Global MASTER-Net observations report
  8. IceCube Alert 190629.81 Global MASTER-Net observations report
  9. GRB 190627A : Xinglong 2.16m optical observation
  10. GRB 190627A: Swift-XRT refined Analysis
  11. GRB 190627A: GMG observation at the second epoch
  12. GRB 190627A: NOT optical observations
  13. GRB 190627A: Optical imaging by D50 from Ondrejov
  14. GRB 190627A: NIR imaging from Liverpool Telescope
  15. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  16. GRB 190627A: NUTTelA-TAO optical counterpart observations
  17. GRB 190627A: Swift-BAT refined analysis (short-soft burst)
  18. GRB 190610A: Further Swift-XRT observations
  19. GRB 190628A: Fermi GBM Final Real-time Localization
  20. GRB 190627A: GMG observation
  21. GRB 190627A: MASTER optical counterpart observation
  22. GRB190627A: VIRT Afterglow observation
  23. GRB 190627A: Montarrenti Observatory optical detection
  24. GRB 190627A: NUTTelA-TAO optical observations
  25. Fermi trigger No 583327924 Global MASTER-Net observations report
  26. GRB 190627A: Enhanced Swift-XRT position
  27. GRB 190627A: Swift/UVOT Detection
  28. GRB 190627A: Swift detection of a burst
  29. Fermi trigger No 583245413 Global MASTER-Net observations report
  30. Fermi trigger No 583245413 Global MASTER-Net observations report
  31. Fermi trigger No 583221986 Global MASTER-Net observations report
  32. GRB 190626B: Fermi GBM Final Real-time Localization
  33. GRB 190619B: AstroSat CZTI detection
  34. GRB 190626A: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 583111521 Global MASTER-Net observations report
  36. Swift Trigger 911102 is likely not an astrophysical event
  37. IceCube-190619A: prompt emission upper limits from AstroSat-CZTI
  38. Swift GRB190624.86 Global MASTER-Net observations report
  39. Swift trigger 911102: D50 optical limit
  40. Swift Trigger 911102: a possible GRB
  41. GRB 190623A: Fermi GBM Final Real-time Localization
  42. Fermi trigger No 582886211 Global MASTER-Net observations report
  43. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  44. GRB 190622A: Fermi GBM Final Real-time Localization
  45. Fermi trigger No 582856902 Global MASTER-Net observations report
  46. GRB 190615B: AstroSat CZTI detection
  47. Fermi trigger No 582748289 Global MASTER-Net observations report
  48. Fermi trigger No 582759998 Global MASTER-Net observations report
  49. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  50. IceCube-190619A: No counterpart candidates in ANTARES data
  51. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  52. IceCube-190619A - HAWC follow-up
  53. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  54. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  55. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  56. GRB 190620A: Fermi GBM Final Real-time Localization
  57. Fermi trigger No 582615488 Global MASTER-Net observations report
  58. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  59. Fermi trigger No 582615488 Global MASTER-Net observations report
  60. IceCube-190619A: not observable by Fermi-GBM
  61. Fermi GBM trigger 190619235/582615488 likely not a GRB
  62. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  63. Fermi trigger No 582646590 Global MASTER-Net observations report
  64. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  65. GRB 190619B: Fermi GBM Final Real-time Localization
  66. GRB 190613A: SEDM Observations
  67. Fermi trigger No 582596766 Global MASTER-Net observations report
  68. GRB 190613B: JCMT SCUBA-2 sub-mm observations
  69. GRB 190619A: Fermi GBM Final Real-time Localization
  70. GRB 190613B: AstroSat CZTI detection
  71. GRB 190611B: AstroSat CZTI detection
  72. Konus-Wind observation of GRB 190613B
  73. GRB 190615B: Insight-HXMT/HE detection
  74. GRB 190615A: Insight-HXMT/HE detection
  75. GRB 190613B: Kitab observatory optical upper limit
  76. Fermi trigger No 582304592 Global MASTER-Net observations report
  77. GRB 190615A: Fermi GBM Final Real-time Localization
  78. GRB 190613A: Kitab and AbAO optical upper limit
  79. Fermi trigger No 582159815 Global MASTER-Net observations report
  80. GRB 190613B: SEDM Observations
  81. GRB 190613A: SEDM Observations
  82. GRB 190610A: Swift/UVOT Upper Limits
  83. GRB 190610A: Swift-XRT observations
  84. GRB 190613B: Optical observation from Asiago Schmidt
  85. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  86. GRB 190611B: CALET Gamma-Ray Burst Monitor detection
  87. GRB 190613B: Insight-HXMT/HE detection
  88. Konus-Wind observation of short/hard GRB 190610A
  89. Konus-Wind observation of GRB 190611B
  90. GRB 190613B: BOOTES-5/JGT early optical observations
  91. GRB 190613B: Optical observations from NOT
  92. Fermi trigger No 582115625 Global MASTER-Net observations report
  93. GRB 190613B: Swift-XRT refined Analysis
  94. GRB 190613A: FRAM-ORM afterglow detection
  95. GRB 190610A: Swift ToO observations
  96. GRB 190613B: Swift-BAT refined analysis
  97. GRB 190613A, Swift-BAT refined analysis
  98. GRB 190613B: KAIT Optical Afterglow Confirmation
  99. GRB 190613B: Swift/UVOT Detection
  100. GRB 190613A: Fermi GBM detection

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