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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"

28047 results found.

  1. LIGO/Virgo S191216ap: galaxies consistent with GW + Neutrino + HAWC position
  2. LIGO/Virgo S191216ap and IceCube neutrino: Swift XRT sources
  3. LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
  4. LIGO/Virgo S191216ap: No significant counterpart candidates in SAGUARO observations
  5. LIGO/Virgo S191213g: Swift UVOT/XRT observations of three ZTF sources
  6. LIGO/Virgo S191213g: MASTER OT J064855.37-055545.7 is a dwarf nova
  7. LIGO/Virgo S191215w : No significant candidates in TAROT - FRAM - GRANDMA observations.
  8. LIGO/Virgo G191216ap: No counterpart candidates in Fermi-LAT observations
  9. LIGO/Virgo S191216ap: no counterpart candidates in the Swift/BAT observations
  10. LIGO/Virgo S191216ap: Coverage and upper limits from MAXI/GSC observations
  11. LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
  12. LIGO/Virgo S191216ap: 1 counterpart neutrino candidate from IceCube neutrino searches
  13. Fermi-LAT Gamma-ray Observations of IceCube-191215A
  14. LIGO/Virgo S191216ap : no neutrino counterpart candidate in ANTARES search
  15. LIGO/Virgo S191216ap: No counterpart candidates in HAWC observations
  16. LIGO/Virgo S191216ap: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo S191215w: no counterpart candidates in the Swift/BAT observations
  18. LIGO/Virgo S191215w: No counterpart candidates in Fermi-LAT observations
  19. IceCube-191215A: Upper limits from a search for additional neutrino events in IceCube
  20. UKIRT photometry of ZTF19acyldun/AT 2019wrt
  21. LIGO/Virgo S191215w: AstroSat CZTI upper limits
  22. LIGO/Virgo S191215w: upper limits from AGILE-GRID observations
  23. LIGO/Virgo S191215w: upper limits from AGILE/MCAL observations
  24. LIGO/Virgo S191215w: Upper limits from Fermi-GBM Observations
  25. LIGO/Virgo S191215w: No counterpart candidates in HAWC observations
  26. LIGO/Virgo S191215w: Coverage and upper limits from MAXI/GSC observations
  27. LIGO/Virgo S191215w : no neutrino counterpart candidate in ANTARES search
  28. LIGO/Virgo S191215w: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  29. LIGO/Virgo S191215w: Identification of a GW compact binary merger candidate
  30. LIGO/Virgo S191215w: Upper limits from IceCube neutrino searches
  31. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  32. LIGO/Virgo S191213g: Upper limits from Insight-HXMT/HE observations
  33. LIGO/Virgo S191213g: LCOGT photometry of ZTF19acymaru/AT2019wnh
  34. LIGO/Virgo S191213g: AstroSat CZTI upper limits
  35. LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility
  36. LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
  37. GRB 191213A: Swift-BAT refined analysis
  38. LIGO/Virgo S191213g: Updated Sky Localization
  39. LIGO/Virgo S191213g: No counterpart candidates in Fermi-LAT observations
  40. LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations
  41. LIGO/Virgo S191213g: Upper limits from Fermi-GBM Observations
  42. LIGO/Virgo S191213g: upper limits from AGILE-GRID observations
  43. LIGO/Virgo S191213g: upper limits from AGILE-MCAL observations
  44. LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
  45. LIGO/Virgo S191213g: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo S191213g: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  48. LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
  49. LIGO/Virgo S191204r: correction to GRAWITA GCN 26390
  50. Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
  51. Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
  52. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL transient candidates discovery.
  53. Possible HAWC-detected GRB 191210A: Swift-XRT observations
  54. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  55. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  56. LIGO/Virgo S191129u: Updated Sky Localization
  57. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  58. LIGO/Virgo S191205ah: AstroSat CZTI upper limits
  59. IceCube-191204A : Upper limits from Insight-HXMT/HE observations
  60. LIGO/Virgo S191205ah: Upper limits from Insight-HXMT/HE observations
  61. LIGO/Virgo S191204r: Upper limits from Insight-HXMT/HE observations
  62. GRB 191203A: Insight-HXMT/HE detection
  63. GRB 191202A: Insight-HXMT/HE detection
  64. IceCube-191204A: No significant detection in HAWC
  65. LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
  66. Fermi-LAT Gamma-ray Observations of IceCube-191204A
  67. LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
  68. LIGO/Virgo S191205ah: No counterpart candidates in Fermi-LAT observations
  69. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  70. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  71. LIGO/Virgo S191205ah: SAGUARO observations and identification of an optical candidate
  72. LIGO/Virgo S191205ah: Upper limits from Fermi-GBM Observations
  73. LIGO/Virgo S191204r: No counterpart candidates in Fermi-LAT observations
  74. LIGO/Virgo S191205ah: Coverage and upper limits from MAXI/GSC observations
  75. LIGO/Virgo S191205ah: upper limits from AGILE-MCAL observations
  76. LIGO/Virgo S191205ah: No counterpart candidates in HAWC observations
  77. LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
  78. LIGO/Virgo S191205ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  79. LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo S191205ah: Upper limits from IceCube neutrino searches
  81. LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
  82. GRB 191130A: Swift-XRT observations
  83. LIGO/Virgo S191204r: Coverage and upper limits from MAXI/GSC observations
  84. IceCube-191204A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  85. LIGO/Virgo S191204r: upper limits from AGILE-GRID observations
  86. LIGO/Virgo S191204r: upper limits from AGILE-MCAL observations
  87. LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
  88. LIGO/Virgo S191204r: Upper limits from IceCube neutrino searches
  89. LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
  90. LIGO/Virgo S191204r: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  91. GRB 191202A: Fermi GBM observation
  92. Fermi trigger No 597049044: Global MASTER-Net observations report
  93. GRB 191130A, a long burst detected in Swift-BAT ground analysis
  94. GRB 191004A: correction to reported GROND upper limits
  95. LIGO/Virgo S191129u: No transient candidates in CALET observations
  96. LIGO/Virgo S191129u: Upper limits from Insight-HXMT/HE observations
  97. LIGO/Virgo S191129u: No counterpart candidates in Fermi-LAT observations
  98. LIGO/Virgo S191129u: Swift/BAT in SAA
  99. LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
  100. LIGO/Virgo S191129u: Coverage and upper limits from MAXI/GSC observations

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