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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"

3039 results found.

  1. Fermi trigger No 600227156: Global MASTER-Net observations report
  2. IceCube-200107A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. LIGO/Virgo S200105ae: Global MASTER-Net observations report
  4. IPN triangulation of GRB 200101A
  5. IceCube-191231A: No significant detection in HAWC
  6. LIGO/Virgo S191216ap: Two candidate counterparts from UKIRT/WFCAM z-band observations
  7. GRB 191227A: MITSuME Akeno optical upper limits
  8. LIGO/Virgo S191222n : No significant candidates in FRAM-TAROT-GRANDMA observations
  9. LIGO/Virgo S191222n: no counterpart candidate in SVOM/GWAC observations
  10. LIGO/Virgo S191213g : No significant candidates found in GRANDMA citizen science observations
  11. LIGO/Virgo S191216ap: VLA/JAGWAR radio monitoring of the 1-sigma HAWC region
  12. LIGO/Virgo S191216ap : No significant candidates in FRAM-TAROT-GRANDMA observations
  13. Fermi trigger No 598543714: Global MASTER-Net observations report
  14. Swift GRB191220.56: Global MASTER-Net observations report
  15. LIGO/Virgo S191216ap, Swift XRT observations: 16 X-ray sources in the HAWC error region search
  16. LIGO/Virgo S191213g: No counterpart candidate in the NOWT observations
  17. LIGO/Virgo S191216ap: No candidates found in CHES observations of HAWC error region
  18. LIGO/Virgo S191216ap: Nanshan follow-up observations
  19. LIGO/Virgo S191213g: No candidates found in J-GEM follow-up observations
  20. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  21. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  22. LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
  23. LIGO/Virgo S191213ai: Global MASTER-Net observations report
  24. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  25. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  26. GRB 191203A: Insight-HXMT/HE detection
  27. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  28. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  29. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  30. IceCube Alert 191204.95: Global MASTER-Net observations report
  31. GRB 191203A: Fermi GBM Final Real-time Localization
  32. Fermi trigger No 596786686: Global MASTER-Net observations report
  33. Fermi trigger No 596690552: Global MASTER-Net observations report
  34. Fermi trigger No 596387570: Global MASTER-Net observations report
  35. Baksan Neutrino Observatory Alert 191124.13: Global MASTER-Net observations report
  36. LIGO/Virgo S191124be: Global MASTER-Net observations report
  37. GRB 191122A: Swift-BAT refined analysis
  38. GRB 191122A: CHES Optical Observations
  39. LIGO/Virgo S191109d: No significant candidates in FRAM-TAROT-GRANDMA observations
  40. LIGO/Virgo S191105e: No significant candidates in FRAM-TAROT-GRANDMA observations
  41. GRB 191106A: Swift-XRT refined Analysis
  42. Fermi trigger No 594592184: Global MASTER-Net observations report
  43. Swift GRB191105.01: Global MASTER-Net observations report
  44. Swift GRB191105.01: Global MASTER-Net OT detection
  45. SGR 1935+2154: Swift-BAT refined analysis
  46. Fermi trigger No 594563923: Global MASTER-Net observations report
  47. GRB 191031A: Fermi GBM detection
  48. IPN triangulation of GRB 191027A
  49. Fermi trigger No 593176520: Global MASTER-Net observations report
  50. Swift GRB191016.17: Global MASTER-Net observations report
  51. Fermi trigger No 592818648: Global MASTER-Net observations report
  52. ANTARES 191011A: AMON + ANTARES Identification of a High-Energy Neutrino + Fermi LAT Coincidence
  53. Fermi trigger No 592211224: Global MASTER-Net observations report
  54. Konus-Wind observation of GRB 191004B
  55. Konus-Wind observation of GRB 191004A
  56. LIGO/Virgo S190930s: no counterpart candidate in the SVOM/GWAC observations
  57. Swift GRB191004.9: Global MASTER-Net OT detection
  58. LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
  59. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  60. Fermi trigger No 591604915: Global MASTER-Net observations report
  61. Konus-Wind observation of GRB 190928A
  62. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  63. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  64. Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
  65. Integral GRB190919.99: Global MASTER-Net observations report
  66. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  67. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  68. LIGO/Virgo S190915ak: No transient candidates in CALET observations
  69. Fermi trigger No 590335819: Global MASTER-Net observations report
  70. LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
  71. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  72. LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
  73. GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
  74. LIGO/Virgo S190915ak : no neutrino counterpart candidate in ANTARES search
  75. LIGO/Virgo S190915ak: Upper Limits from AGILE-GRID observations
  76. LIGO/Virgo S190915ak: No counterpart candidate in AGILE-MCAL observations
  77. LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  78. LIGO/Virgo S190915ak: Identification of a GW compact binary merger candidate
  79. GRB 190915A: BALROG localization (Fermi Trigger 590219102 / GRB 190915240)
  80. GRB 190915A: Fermi GBM Final Real-time Localization
  81. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  82. LIGO/Virgo S190814bv: No counterpart candidate after completion of GRAWITA VST-ESO PARANAL transient survey.
  83. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  84. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  85. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  86. LIGO/Virgo S190901ap: Gaia Photometric Alerts transient candidates
  87. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  88. GRB 190829A: GTC confirmation of an associated Type Ic-BL Supernova
  89. Fermi trigger No 589419513 Global MASTER-Net observations report
  90. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  91. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  92. LIGO/Virgo S190901ap : GRAWITA photometric observation of candidate ZTFabvizsw and GCN 25618 revision
  93. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  94. LIGO/Virgo S190901ap: Upper limits from Insight-HXMT/HE observations
  95. Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
  96. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  97. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  98. GRB 190829A: NOEMA detection of the mm afterglow
  99. GRB 190831A: Fermi GBM Final Real-time Localization
  100. GRB 190829A, Swift-BAT refined analysis

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