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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
  2. LIGO/Virgo S191213g: Coverage and upper limits from MAXI/GSC observations
  3. LIGO/Virgo S191213g: Identification of a GW compact binary merger candidate
  4. LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  5. LIGO/Virgo S191213g: Global MASTER-Net observations report
  6. LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
  7. GRB 191213A: Swift detection of a burst
  8. LIGO/Virgo S191205ah: Gaia Photometric Alerts transient candidates
  9. LIGO/Virgo S191204r: correction to GRAWITA GCN 26390
  10. LIGO/Virgo S191212q: Retraction of GW compact binary merger candidate
  11. LIGO/Virgo S191212q: Global MASTER-Net observations report
  12. Baksan Neutrino Observatory Alert 191211.1: Global MASTER-Net observations report
  13. Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
  14. Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
  15. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL transient candidates discovery.
  16. Possible HAWC-detected GRB 191210A: Swift-XRT observations
  17. Fermi GBM trigger 597737032/191211253 is not a GRB
  18. Fermi trigger No 597737032: Global MASTER-Net observations report
  19. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  20. GRB 191207A: Possible GRB detected in Fermi-LAT blind search
  21. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  22. LIGO/Virgo S191129u: Updated Sky Localization
  23. LIGO/Virgo S191205ah: MASTER OT 1.5m OSN imaging and 10.4m GTC spectroscopy
  24. LIGO/Virgo S191205ah: MITSuME Observation of MASTER OT J123123.61-043847.2
  25. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  26. LIGO/Virgo S191205ah: MASTER OT detection
  27. GRB191102A: AstroSat CZTI discovery of a burst
  28. LIGO/Virgo S191205ah: Not observable by CALET
  29. GRB191105B: AstroSat CZTI detection
  30. LIGO/Virgo S191205ah: AstroSat CZTI upper limits
  31. IceCube-191204A : Upper limits from Insight-HXMT/HE observations
  32. LIGO/Virgo S191205ah: Upper limits from Insight-HXMT/HE observations
  33. LIGO/Virgo S191204r: Upper limits from Insight-HXMT/HE observations
  34. GRB 191203A: Insight-HXMT/HE detection
  35. GRB 191202A: Insight-HXMT/HE detection
  36. IceCube-191204A: No significant detection in HAWC
  37. LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
  38. Fermi-LAT Gamma-ray Observations of IceCube-191204A
  39. LIGO/Virgo S191205ah: GMG detection of SAGUARO transient
  40. LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
  41. LIGO/Virgo S191205ah: Pan-STARRS1 previous detections of SAGUARO transient
  42. LIGO/Virgo S191205ah: No counterpart candidates in Fermi-LAT observations
  43. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  44. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  45. LIGO/Virgo S191205ah: SAGUARO observations and identification of an optical candidate
  46. LIGO/Virgo S191205ah: Upper limits from Fermi-GBM Observations
  47. LIGO/Virgo S191204r: No transient candidates in CALET observations
  48. LIGO/Virgo S191204r: No counterpart candidates in Fermi-LAT observations
  49. LIGO/Virgo S191205ah: Coverage and upper limits from MAXI/GSC observations
  50. LIGO/Virgo S191205ah: upper limits from AGILE-MCAL observations
  51. LIGO/Virgo S191205ah: No counterpart candidates in HAWC observations
  52. LIGO/Virgo S191205ah: Global MASTER-Net observations report
  53. LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
  54. LIGO/Virgo S191205ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  55. LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo S191205ah: Upper limits from IceCube neutrino searches
  57. LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
  58. GRB 191205A: Fermi GBM Final Real-time Localization
  59. GRB 191130A: Swift-XRT observations
  60. IceCube-191204A: Upper limits from Fermi-GBM Observations
  61. Konus-Wind observation of GRB191202A
  62. IceCube Alert 191204.95: Global MASTER-Net observations report
  63. LIGO/Virgo S191204r: not observable by Fermi-GBM
  64. IceCube-191204A - IceCube observation of a high-energy neutrino candidate event
  65. LIGO/Virgo S191204r: Coverage and upper limits from MAXI/GSC observations
  66. IceCube-191204A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  67. LIGO/Virgo S191204r: upper limits from AGILE-GRID observations
  68. LIGO/Virgo S191204r: upper limits from AGILE-MCAL observations
  69. LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
  70. LIGO/Virgo S191204r: Upper limits from IceCube neutrino searches
  71. LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo S191204r: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  73. LIGO/Virgo S191204r: Global MASTER-Net observations report
  74. GRB 191130A: Swift ToO observations
  75. GRB 191202A: Fermi-LAT detection
  76. GRB 191202A: Fermi GBM observation
  77. Fermi trigger No 597049044: Global MASTER-Net observations report
  78. GRB 191130A, a long burst detected in Swift-BAT ground analysis
  79. GRB 191202A: AstroSat CZTI detection
  80. GRB 191203A: Fermi GBM Final Real-time Localization
  81. GRB 191004A: correction to reported GROND upper limits
  82. GRB 191202A: Fermi GBM Final Real-time Localization
  83. GRB 191201A: AstroSat CZTI detection
  84. LIGO/Virgo S191129u: No transient candidates in CALET observations
  85. Fermi trigger No 596786686: Global MASTER-Net observations report
  86. Fermi trigger No 596808579: Global MASTER-Net observations report
  87. Fermi GBM trigger 596808579/191130507 is not a GRB
  88. LIGO/Virgo S191129u: Upper limits from Insight-HXMT/HE observations
  89. GRB 191129A: AstroSat CZTI detection
  90. LIGO/Virgo S191129u: No counterpart candidates in Fermi-LAT observations
  91. LIGO/Virgo S191129u: not observable by Fermi-GBM
  92. LIGO/Virgo S191129u: Swift/BAT in SAA
  93. LIGO/Virgo S191129u: no INTEGRAL data available
  94. LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
  95. LIGO/Virgo S191129u: Coverage and upper limits from MAXI/GSC observations
  96. LIGO/Virgo S191129u: upper limits from AGILE/GRID observations
  97. LIGO/Virgo S191129u : no neutrino counterpart candidate in ANTARES search
  98. LIGO/Virgo S191129u: upper limits from AGILE/MCAL observations
  99. LIGO/Virgo S191129u: Upper limits from IceCube neutrino searches
  100. LIGO/Virgo S191129u: Global MASTER-Net observations report

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