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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"

5833 results found.

  1. LIGO/Virgo S191215w: Identification of a GW compact binary merger candidate
  2. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. IceCube-191215A - IceCube observation of a high-energy neutrino candidate event
  4. LIGO/Virgo S191205ah: Candidates from the Zwicky Transient Facility Public Survey
  5. Fermi trigger No 597955752: Global MASTER-Net observations report
  6. LIGO/Virgo S191213ai: Global MASTER-Net observations report
  7. Fermi trigger No 597909938: Global MASTER-Net observations report
  8. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  9. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  10. LIGO/Virgo S191205ah: MITSuME Observation of MASTER OT J123123.61-043847.2
  11. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  12. IceCube-191204A: No significant detection in HAWC
  13. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  14. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  15. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  16. Fermi GBM trigger 596808579/191130507 is not a GRB
  17. Fermi trigger No 596690552: Global MASTER-Net observations report
  18. Baksan Neutrino Observatory Alert 191128.17: Global MASTER-Net observations report
  19. Baksan Neutrino Observatory Alert 191127.25: Global MASTER-Net observations report
  20. Fermi trigger No 596387570: Global MASTER-Net observations report
  21. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  22. GRB 191122A: Swift detection of a burst
  23. IceCube-191119A: No significant detection in HAWC
  24. LIGO/Virgo S191109d: Not observable by CALET
  25. LIGO/Virgo S191110af: Identification of a GW unmodeled transient candidate
  26. LIGO/Virgo S191110af: Global MASTER-Net observations report
  27. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  28. LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
  29. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  30. LIGO/Virgo S191109d: AstroSat CZTI upper limits
  31. LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
  32. LIGO/Virgo S191109d: Global MASTER-Net observations report
  33. LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
  34. LIGO/Virgo S191109d: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
  35. LIGO/Virgo S191109d: upper limits from AGILE/MCAL observations
  36. LIGO/Virgo S191109d: Coverage and upper limits from MAXI/GSC observations
  37. LIGO/Virgo S191109d: Upper limits from IceCube neutrino searches
  38. LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
  39. ZTF19abvizsw: Upper limits from Konus-Wind observations
  40. Fermi trigger No 594592184: Global MASTER-Net observations report
  41. Swift GRB191105.01: Global MASTER-Net observations report
  42. Swift GRB191105.01: Global MASTER-Net OT detection
  43. Fermi GBM GRBs 191104 A, B, C and triggers 594534420/191104185 and 594563923/191104527 are not GRBs
  44. Fermi trigger No 594557071: Global MASTER-Net observations report
  45. Fermi trigger No 594551878: Global MASTER-Net observations report
  46. Fermi trigger No 594528816: Global MASTER-Net observations report
  47. GRB 191104B: Fermi GBM Final Real-time Localization
  48. GRB 191101A: Swift detection of a burst
  49. GRB 191031D: MITSuME Akeno optical upper limits
  50. GRB 191031C: Swift detection of a burst
  51. IPN triangulation of GRB 191025B (short)
  52. Fermi trigger No 593176520: Global MASTER-Net observations report
  53. GRB 191017A: Fermi GBM Final Localization
  54. GRB191016A: MITSuME Okayama optical observation
  55. 191017A: BALROG localization (Fermi Trigger 592997024 / GRB 191017391)
  56. Baksan Neutrino Observatory Alert 191016.51: Global MASTER-Net observations report
  57. GRB 191016A: Swift detection of a burst
  58. GRB 191009A: AstroSat CZTI detection
  59. GRB 191009A: BALROG localization (Fermi Trigger 592297741 / GRB 191009298)
  60. TESS Detection of the Optical Emission from the Possible Untriggered GRB Associated with ZTF19abvizsw
  61. Fermi/GBM observation of a bright burst from magnetar SGR 1935+2154
  62. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  63. GRB 190928A: AstroSat CZTI detection
  64. Swift GRB191004.9: Global MASTER-Net OT detection
  65. GRB 191004B: Swift detection of a burst with an optical counterpart
  66. FACT follow-up of IceCube-191001A
  67. IceCube-191001A: HAWC follow-up
  68. GRB 190919A: AstroSat CZTI detection
  69. LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
  70. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
  71. Fermi-LAT Gamma-ray Observations of IceCube-191001A
  72. LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
  73. LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
  74. IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  75. IceCube-191001A - IceCube observation of a high-energy neutrino candidate event
  76. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  77. LIGO/Virgo S190930t and S190930s: MASTER OT J205529.78+220725.5/AT2019rpr further analysis
  78. GRB 191001B: MITSuME Akeno optical upper limits
  79. LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
  80. LIGO/Virgo S190930t and S190930s: MASTER PSN in unknown disk galaxy
  81. LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
  82. LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
  83. LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
  84. LIGO/Virgo S190930t: Upper limits from CALET observations.
  85. LIGO/Virgo S190930s: Upper limits from CALET observations.
  86. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  87. LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
  88. LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
  89. LIGO/Virgo S190930s: no counterpart candidates in AGILE-GRID observations
  90. LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
  91. LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
  92. LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  93. GRB 190928A: Insight-HXMT/HE detection
  94. LIGO/Virgo S190930s: No counterpart candidates in AGILE-MCAL observations
  95. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  96. LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo S190930t: Global MASTER-Net observations report
  98. LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
  99. LIGO/Virgo S190930s: Upper limits from IceCube neutrino searches
  100. LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation

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