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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 190627A: NUTTelA-TAO optical observations
  2. Fermi trigger No 583327924 Global MASTER-Net observations report
  3. GRB 190627A: Enhanced Swift-XRT position
  4. GRB 190627A: Swift/UVOT Detection
  5. GRB 190627A: Swift detection of a burst
  6. Fermi trigger No 583245413 Global MASTER-Net observations report
  7. Fermi trigger No 583245413 Global MASTER-Net observations report
  8. Fermi trigger No 583221986 Global MASTER-Net observations report
  9. GRB 190626B: Fermi GBM Final Real-time Localization
  10. GRB 190619B: AstroSat CZTI detection
  11. GRB 190626A: Fermi GBM Final Real-time Localization
  12. Fermi trigger No 583111521 Global MASTER-Net observations report
  13. Swift Trigger 911102 is likely not an astrophysical event
  14. IceCube-190619A: prompt emission upper limits from AstroSat-CZTI
  15. Swift GRB190624.86 Global MASTER-Net observations report
  16. Swift trigger 911102: D50 optical limit
  17. Swift Trigger 911102: a possible GRB
  18. GRB 190623A: Fermi GBM Final Real-time Localization
  19. Fermi trigger No 582886211 Global MASTER-Net observations report
  20. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  21. GRB 190622A: Fermi GBM Final Real-time Localization
  22. Fermi trigger No 582856902 Global MASTER-Net observations report
  23. GRB 190615B: AstroSat CZTI detection
  24. Fermi trigger No 582748289 Global MASTER-Net observations report
  25. Fermi trigger No 582759998 Global MASTER-Net observations report
  26. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  27. IceCube-190619A: No counterpart candidates in ANTARES data
  28. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  29. IceCube-190619A - HAWC follow-up
  30. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  31. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  32. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  33. GRB 190620A: Fermi GBM Final Real-time Localization
  34. Fermi trigger No 582615488 Global MASTER-Net observations report
  35. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  36. Fermi trigger No 582615488 Global MASTER-Net observations report
  37. IceCube-190619A: not observable by Fermi-GBM
  38. Fermi GBM trigger 190619235/582615488 likely not a GRB
  39. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  40. Fermi trigger No 582646590 Global MASTER-Net observations report
  41. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  42. GRB 190619B: Fermi GBM Final Real-time Localization
  43. GRB 190613A: SEDM Observations
  44. Fermi trigger No 582596766 Global MASTER-Net observations report
  45. GRB 190613B: JCMT SCUBA-2 sub-mm observations
  46. GRB 190619A: Fermi GBM Final Real-time Localization
  47. GRB 190613B: AstroSat CZTI detection
  48. GRB 190611B: AstroSat CZTI detection
  49. Konus-Wind observation of GRB 190613B
  50. GRB 190615B: Insight-HXMT/HE detection
  51. GRB 190615A: Insight-HXMT/HE detection
  52. GRB 190613B: Kitab observatory optical upper limit
  53. Fermi trigger No 582304592 Global MASTER-Net observations report
  54. GRB 190615A: Fermi GBM Final Real-time Localization
  55. GRB 190613A: Kitab and AbAO optical upper limit
  56. Fermi trigger No 582159815 Global MASTER-Net observations report
  57. GRB 190613B: SEDM Observations
  58. GRB 190613A: SEDM Observations
  59. GRB 190610A: Swift/UVOT Upper Limits
  60. GRB 190610A: Swift-XRT observations
  61. GRB 190613B: Optical observation from Asiago Schmidt
  62. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  63. GRB 190611B: CALET Gamma-Ray Burst Monitor detection
  64. GRB 190613B: Insight-HXMT/HE detection
  65. Konus-Wind observation of short/hard GRB 190610A
  66. Konus-Wind observation of GRB 190611B
  67. GRB 190613B: BOOTES-5/JGT early optical observations
  68. GRB 190613B: Optical observations from NOT
  69. Fermi trigger No 582115625 Global MASTER-Net observations report
  70. GRB 190613B: Swift-XRT refined Analysis
  71. GRB 190613A: FRAM-ORM afterglow detection
  72. GRB 190610A: Swift ToO observations
  73. GRB 190613B: Swift-BAT refined analysis
  74. GRB 190613A, Swift-BAT refined analysis
  75. GRB 190613B: KAIT Optical Afterglow Confirmation
  76. GRB 190613B: Swift/UVOT Detection
  77. GRB 190613A: Fermi GBM detection
  78. GRB 190613A: Swift/UVOT Detection
  79. GRB 190613B: Fermi GBM observation
  80. GRB 190611B: BALROG localization (Fermi Trigger 581986074 / GRB 190611950)
  81. GRB 190613B: Enhanced Swift-XRT position
  82. IPN Triangulation of GRB 190611B
  83. GRB 190613A: Swift-XRT refined Analysis
  84. GRB 190613A: Enhanced Swift-XRT position
  85. GRB 190613B: BALROG localization (Fermi Trigger 582115625 / GRB 190613449)
  86. GRB 190613B: Swift detection of a burst with an optical counterpart
  87. GRB 190613B: Fermi GBM Final Real-time Localization
  88. GRB 190610A: CALET Gamma-Ray Burst Monitor detection
  89. GRB 190609A: AstroSat CZTI detection
  90. GRB 190613A: MASTER OT detection
  91. Swift GRB190613.17 Global MASTER-Net observations report
  92. GRB 190613A: KAIT Optical Afterglow Confirmation
  93. GRB 190613A: BALROG localization (Fermi Trigger 582091643 / GRB 190613172)
  94. GRB 190613A: Fermi GBM Final Real-time Localization
  95. GRB 190613A: Swift detection of a burst with an optical counterpart
  96. Fermi trigger No 582091643 Global MASTER-Net observations report
  97. Fermi trigger No 582012834 Global MASTER-Net observations report
  98. Fermi trigger No 581986074 Global MASTER-Net observations report
  99. GRB 190611B: Fermi GBM detection
  100. GRB 190611A: Swift-XRT refined Analysis

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