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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 190630C: Swift detection of a burst
  2. LIGO/Virgo S190630ag: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo S190630ag: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  4. LIGO/Virgo S190630ag: No neutrino counterpart candidates in ANTARES search
  5. LIGO/Virgo S190630ag: No counterpart candidates in HAWC observations
  6. LIGO/Virgo S190630ag: Identification of a GW compact binary merger candidate
  7. LIGO/Virgo S190630ag Global MASTER-Net observations report
  8. LIGO/Virgo S190630ag: Upper limits from IceCube neutrino searches
  9. GRB 190630B: Swift-XRT refined Analysis
  10. GRB 190630B, Swift-BAT refined analysis
  11. IceCube-190629A: Upper limits from Fermi-GBM Observations
  12. GRB 190627A: VLT/FORS2 spectroscopic redshift
  13. Fermi trigger No 583567803 Global MASTER-Net observations report
  14. GRB Swift Trigger 912102: KAIT Optical Afterglow Candidate
  15. Swift Trigger 912102: possible GRB 190630B
  16. GRB 190630A: Fermi GBM Final Real-time Localization
  17. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  18. IceCube-190629A - IceCube observation of a high-energy neutrino candidate event
  19. Baksan Neutrino Observatory Alert 190629.56 Global MASTER-Net observations report
  20. IceCube Alert 190629.81 Global MASTER-Net observations report
  21. GRB 190627A : Xinglong 2.16m optical observation
  22. GRB 190627A: Swift-XRT refined Analysis
  23. GRB 190627A: GMG observation at the second epoch
  24. GRB 190627A: NOT optical observations
  25. GRB 190627A: Optical imaging by D50 from Ondrejov
  26. GRB 190627A: NIR imaging from Liverpool Telescope
  27. GRB 190627A: Optical imaging and spectroscopy from Calar Alto
  28. GRB 190627A: NUTTelA-TAO optical counterpart observations
  29. GRB 190627A: Swift-BAT refined analysis (short-soft burst)
  30. GRB 190610A: Further Swift-XRT observations
  31. GRB 190628A: Fermi GBM Final Real-time Localization
  32. GRB 190627A: GMG observation
  33. GRB 190627A: MASTER optical counterpart observation
  34. GRB190627A: VIRT Afterglow observation
  35. GRB 190627A: Montarrenti Observatory optical detection
  36. GRB 190627A: NUTTelA-TAO optical observations
  37. Fermi trigger No 583327924 Global MASTER-Net observations report
  38. GRB 190627A: Enhanced Swift-XRT position
  39. GRB 190627A: Swift/UVOT Detection
  40. GRB 190627A: Swift detection of a burst
  41. Fermi trigger No 583245413 Global MASTER-Net observations report
  42. Fermi trigger No 583245413 Global MASTER-Net observations report
  43. Fermi trigger No 583221986 Global MASTER-Net observations report
  44. GRB 190626B: Fermi GBM Final Real-time Localization
  45. GRB 190619B: AstroSat CZTI detection
  46. GRB 190626A: Fermi GBM Final Real-time Localization
  47. Fermi trigger No 583111521 Global MASTER-Net observations report
  48. Swift Trigger 911102 is likely not an astrophysical event
  49. IceCube-190619A: prompt emission upper limits from AstroSat-CZTI
  50. Swift GRB190624.86 Global MASTER-Net observations report
  51. Swift trigger 911102: D50 optical limit
  52. Swift Trigger 911102: a possible GRB
  53. GRB 190623A: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 582886211 Global MASTER-Net observations report
  55. GRB 190622A: BALROG localization (Fermi Trigger 582886211 / GRB 190622368)
  56. GRB 190622A: Fermi GBM Final Real-time Localization
  57. Fermi trigger No 582856902 Global MASTER-Net observations report
  58. GRB 190615B: AstroSat CZTI detection
  59. Fermi trigger No 582748289 Global MASTER-Net observations report
  60. Fermi trigger No 582759998 Global MASTER-Net observations report
  61. Fermi-LAT Gamma-ray Observations of IceCube-190619A
  62. IceCube-190619A: No counterpart candidates in ANTARES data
  63. IceCube-190619A: IceCube additional correlated neutrino search: upper limits
  64. IceCube-190619A - HAWC follow-up
  65. LIGO/Virgo S190426c: Swift UVOT - no new counterpart candidates identified
  66. LIGO/Virgo S190510g: Swift UVOT - no new counterpart candidates identified
  67. GRB 190620A: BALROG localization (Fermi Trigger 582725415 / GRB 190620507)
  68. GRB 190620A: Fermi GBM Final Real-time Localization
  69. Fermi trigger No 582615488 Global MASTER-Net observations report
  70. IceCube-190619A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  71. Fermi trigger No 582615488 Global MASTER-Net observations report
  72. IceCube-190619A: not observable by Fermi-GBM
  73. Fermi GBM trigger 190619235/582615488 likely not a GRB
  74. IceCube-190619A - IceCube observation of a high-energy neutrino candidate event
  75. Fermi trigger No 582646590 Global MASTER-Net observations report
  76. GRB 190619B: BALROG localization (Fermi Trigger 582646590 / GRB 190619595)
  77. GRB 190619B: Fermi GBM Final Real-time Localization
  78. GRB 190613A: SEDM Observations
  79. Fermi trigger No 582596766 Global MASTER-Net observations report
  80. GRB 190613B: JCMT SCUBA-2 sub-mm observations
  81. GRB 190619A: Fermi GBM Final Real-time Localization
  82. GRB 190613B: AstroSat CZTI detection
  83. GRB 190611B: AstroSat CZTI detection
  84. Konus-Wind observation of GRB 190613B
  85. GRB 190615B: Insight-HXMT/HE detection
  86. GRB 190615A: Insight-HXMT/HE detection
  87. GRB 190613B: Kitab observatory optical upper limit
  88. Fermi trigger No 582304592 Global MASTER-Net observations report
  89. GRB 190615A: Fermi GBM Final Real-time Localization
  90. GRB 190613A: Kitab and AbAO optical upper limit
  91. Fermi trigger No 582159815 Global MASTER-Net observations report
  92. GRB 190613B: SEDM Observations
  93. GRB 190613A: SEDM Observations
  94. GRB 190610A: Swift/UVOT Upper Limits
  95. GRB 190610A: Swift-XRT observations
  96. GRB 190613B: Optical observation from Asiago Schmidt
  97. GRB 190613B: GROND Detection of the Optical/NIR Afterglow
  98. GRB 190611B: CALET Gamma-Ray Burst Monitor detection
  99. GRB 190613B: Insight-HXMT/HE detection
  100. Konus-Wind observation of short/hard GRB 190610A

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