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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 190628A: Fermi GBM Final Real-time Localization
  2. GRB 190627A: GMG observation
  3. GRB 190627A: MASTER optical counterpart observation
  4. GRB190627A: VIRT Afterglow observation
  5. GRB 190627A: Montarrenti Observatory optical detection
  6. GRB 190627A: NUTTelA-TAO optical observations
  7. Fermi trigger No 583327924 Global MASTER-Net observations report
  8. GRB 190627A: Enhanced Swift-XRT position
  9. GRB 190627A: Swift/UVOT Detection
  10. GRB 190627A: Swift detection of a burst
  11. Fermi trigger No 583245413 Global MASTER-Net observations report
  12. Fermi trigger No 583245413 Global MASTER-Net observations report
  13. Fermi trigger No 583221986 Global MASTER-Net observations report
  14. GRB 190626B: Fermi GBM Final Real-time Localization
  15. GRB 190619B: AstroSat CZTI detection
  16. GRB 190626A: Fermi GBM Final Real-time Localization
  17. Fermi trigger No 583111521 Global MASTER-Net observations report
  18. Swift Trigger 911102 is likely not an astrophysical event
  19. IceCube-190619A: prompt emission upper limits from AstroSat-CZTI
  20. Swift GRB190624.86 Global MASTER-Net observations report
  21. Swift trigger 911102: D50 optical limit
  22. Swift Trigger 911102: a possible GRB
  23. GRB 190623A: Fermi GBM Final Real-time Localization
  24. Fermi trigger No 582886211 Global MASTER-Net observations report
  25. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  26. GRB 190622A: Fermi GBM Final Real-time Localization
  27. Fermi trigger No 582856902 Global MASTER-Net observations report
  28. GRB 190615B: AstroSat CZTI detection
  29. Fermi trigger No 582748289 Global MASTER-Net observations report
  30. Fermi trigger No 582759998 Global MASTER-Net observations report
  31. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  32. IceCube-190619A: No counterpart candidates in ANTARES data
  33. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  34. IceCube-190619A - HAWC follow-up
  35. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  36. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  37. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  38. GRB 190620A: Fermi GBM Final Real-time Localization
  39. Fermi trigger No 582615488 Global MASTER-Net observations report
  40. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  41. Fermi trigger No 582615488 Global MASTER-Net observations report
  42. IceCube-190619A: not observable by Fermi-GBM
  43. Fermi GBM trigger 190619235/582615488 likely not a GRB
  44. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  45. Fermi trigger No 582646590 Global MASTER-Net observations report
  46. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  47. GRB 190619B: Fermi GBM Final Real-time Localization
  48. GRB 190613A: SEDM Observations
  49. Fermi trigger No 582596766 Global MASTER-Net observations report
  50. GRB 190613B: JCMT SCUBA-2 sub-mm observations
  51. GRB 190619A: Fermi GBM Final Real-time Localization
  52. GRB 190613B: AstroSat CZTI detection
  53. GRB 190611B: AstroSat CZTI detection
  54. Konus-Wind observation of GRB 190613B
  55. GRB 190615B: Insight-HXMT/HE detection
  56. GRB 190615A: Insight-HXMT/HE detection
  57. GRB 190613B: Kitab observatory optical upper limit
  58. Fermi trigger No 582304592 Global MASTER-Net observations report
  59. GRB 190615A: Fermi GBM Final Real-time Localization
  60. GRB 190613A: Kitab and AbAO optical upper limit
  61. Fermi trigger No 582159815 Global MASTER-Net observations report
  62. GRB 190613B: SEDM Observations
  63. GRB 190613A: SEDM Observations
  64. GRB 190610A: Swift/UVOT Upper Limits
  65. GRB 190610A: Swift-XRT observations
  66. GRB 190613B: Optical observation from Asiago Schmidt
  67. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  68. GRB 190611B: CALET Gamma-Ray Burst Monitor detection
  69. GRB 190613B: Insight-HXMT/HE detection
  70. Konus-Wind observation of short/hard GRB 190610A
  71. Konus-Wind observation of GRB 190611B
  72. GRB 190613B: BOOTES-5/JGT early optical observations
  73. GRB 190613B: Optical observations from NOT
  74. Fermi trigger No 582115625 Global MASTER-Net observations report
  75. GRB 190613B: Swift-XRT refined Analysis
  76. GRB 190613A: FRAM-ORM afterglow detection
  77. GRB 190610A: Swift ToO observations
  78. GRB 190613B: Swift-BAT refined analysis
  79. GRB 190613A, Swift-BAT refined analysis
  80. GRB 190613B: KAIT Optical Afterglow Confirmation
  81. GRB 190613B: Swift/UVOT Detection
  82. GRB 190613A: Fermi GBM detection
  83. GRB 190613A: Swift/UVOT Detection
  84. GRB 190613B: Fermi GBM observation
  85. GRB 190611B: BALROG localization (Fermi Trigger 581986074 / GRB 190611950)
  86. GRB 190613B: Enhanced Swift-XRT position
  87. IPN Triangulation of GRB 190611B
  88. GRB 190613A: Swift-XRT refined Analysis
  89. GRB 190613A: Enhanced Swift-XRT position
  90. GRB 190613B: BALROG localization (Fermi Trigger 582115625 / GRB 190613449)
  91. GRB 190613B: Swift detection of a burst with an optical counterpart
  92. GRB 190613B: Fermi GBM Final Real-time Localization
  93. GRB 190610A: CALET Gamma-Ray Burst Monitor detection
  94. GRB 190609A: AstroSat CZTI detection
  95. GRB 190613A: MASTER OT detection
  96. Swift GRB190613.17 Global MASTER-Net observations report
  97. GRB 190613A: KAIT Optical Afterglow Confirmation
  98. GRB 190613A: BALROG localization (Fermi Trigger 582091643 / GRB 190613172)
  99. GRB 190613A: Fermi GBM Final Real-time Localization
  100. GRB 190613A: Swift detection of a burst with an optical counterpart

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