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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"

5831 results found.

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

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