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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"

7448 results found.

  1. LIGO/Virgo S191213g: MASTER OT J064855.37-055545.7 is a dwarf nova
  2. LIGO/Virgo S191216ap: No Candidates from the Zwicky Transient Facility
  3. LIGO/Virgo S191216ap: Correction to GCN 26460 (IceCube event coincident with GW event)
  4. LIGO/Virgo S191216ap: Upper limits from Fermi-GBM Observations
  5. LIGO/Virgo S191216ap: 1 counterpart neutrino candidate from IceCube neutrino searches
  6. Fermi-LAT Gamma-ray Observations of IceCube-191215A
  7. LIGO/Virgo S191216ap : no neutrino counterpart candidate in ANTARES search
  8. LIGO/Virgo S191216ap: No counterpart candidates in HAWC observations
  9. LIGO/Virgo S191216ap: Identification of a GW compact binary merger candidate
  10. UKIRT photometry of ZTF19acyldun/AT 2019wrt
  11. LIGO/Virgo S191215w: AstroSat CZTI upper limits
  12. LIGO/Virgo S191215w: upper limits from AGILE-GRID observations
  13. LIGO/Virgo S191215w: Upper limits from Fermi-GBM Observations
  14. LIGO/Virgo S191215w: No counterpart candidates in HAWC observations
  15. LIGO/Virgo S191215w : no neutrino counterpart candidate in ANTARES search
  16. LIGO/Virgo S191215w: Identification of a GW compact binary merger candidate
  17. LIGO/Virgo S191215w: Upper limits from IceCube neutrino searches
  18. IceCube-191215A: not observable by Fermi-GBM
  19. LIGO/Virgo S191213g: Additional candidates from the Zwicky Transient Facility
  20. IceCube-191215A - IceCube observation of a high-energy neutrino candidate event
  21. LIGO/Virgo S191213g: LCOGT photometry of ZTF19acymaru/AT2019wnh
  22. LIGO/Virgo S191213g: WHT spectroscopy of candidate counterparts
  23. LIGO/Virgo S191213g: GRAWITA TNG classification of ZTF19acykzsk
  24. LIGO/Virgo S191213g: AstroSat CZTI upper limits
  25. LIGO/Virgo S191213g: Candidates from the Zwicky Transient Facility
  26. LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
  27. LIGO/Virgo S191213g: Updated Sky Localization
  28. LIGO/Virgo S191205ah: Candidates from the Zwicky Transient Facility Public Survey
  29. LIGO/Virgo S191213ai: Retraction of GW compact binary merger candidate
  30. LIGO/Virgo S191213g: Upper limits from Fermi-GBM Observations
  31. LIGO/Virgo S191213g: upper limits from AGILE-GRID observations
  32. LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
  33. LIGO/Virgo S191213g: Identification of a GW compact binary merger candidate
  34. LIGO/Virgo S191213g: Upper limits from IceCube neutrino searches
  35. LIGO/Virgo S191205ah: Gaia Photometric Alerts transient candidates
  36. LIGO/Virgo S191212q: Retraction of GW compact binary merger candidate
  37. Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
  38. Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
  39. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  40. LIGO/Virgo S191129u: Updated Sky Localization
  41. LIGO/Virgo S191205ah: Not observable by CALET
  42. LIGO/Virgo S191205ah: AstroSat CZTI upper limits
  43. LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
  44. LIGO/Virgo S191205ah: GMG detection of SAGUARO transient
  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 S191205ah: No counterpart candidates in HAWC observations
  48. LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
  49. LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
  50. LIGO/Virgo S191205ah: Upper limits from IceCube neutrino searches
  51. IceCube-191204A: Upper limits from Fermi-GBM Observations
  52. IceCube-191204A - IceCube observation of a high-energy neutrino candidate event
  53. LIGO/Virgo S191204r: upper limits from AGILE-GRID observations
  54. LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
  55. LIGO/Virgo S191204r: Upper limits from IceCube neutrino searches
  56. LIGO/Virgo S191204r: Identification of a GW compact binary merger candidate
  57. GRB 191130A: Swift ToO observations
  58. LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
  59. LIGO/Virgo S191129u: upper limits from AGILE/GRID observations
  60. LIGO/Virgo S191129u : no neutrino counterpart candidate in ANTARES search
  61. LIGO/Virgo S191129u: Upper limits from IceCube neutrino searches
  62. LIGO/Virgo S191129u: Identification of a GW compact binary merger candidate
  63. IceCube-191122A: Not observable by Fermi-GBM
  64. LIGO/Virgo S191124be: Retraction of GW compact binary merger candidate
  65. GRB 191123A: Swift/UVOT detection
  66. GRB 191123A: Swift detection of a burst with an optical counterpart
  67. IceCube-191122A - IceCube observation of a high-energy neutrino candidate event
  68. GRB 191122A: CHES Optical Observations
  69. GRB 191122A: Swift detection of a burst
  70. IceCube-191119A: No neutrino counterpart candidates in ANTARES search
  71. LIGO/Virgo S191120at: Retraction of GW compact binary merger candidate
  72. LIGO/Virgo S191120aj: Retraction of GW compact binary merger candidate
  73. IceCube-191119A: Upper limits from Fermi-GBM Observations
  74. IceCube-191119A - IceCube observation of a high-energy neutrino candidate event
  75. LIGO/Virgo S191117j: Retraction of GW compact binary merger candidate
  76. Swift Trigger 937114 is not an astrophysical source
  77. LIGO/Virgo S191110af: Retraction of GW unmodeled transient candidate
  78. LIGO/Virgo S191110af: Upper limits from KM3NeT MeV neutrino search.
  79. LIGO/Virgo S191105e: Updated Sky Localization
  80. LIGO/Virgo S191110af: Potential pulsar counterparts
  81. LIGO/Virgo S191110af: Upper limits from CALET observations.
  82. LIGO/Virgo S191109d: Not observable by CALET
  83. LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
  84. LIGO/Virgo S191110af: No neutrino counterpart candidate in ANTARES search
  85. LIGO/Virgo S191110af: Upper limits from Fermi-GBM Observations
  86. LIGO/Virgo S191110af: Identification of a GW unmodeled transient candidate
  87. LIGO/Virgo S191110af: Upper limits from IceCube neutrino searches
  88. LIGO/Virgo S191110x: Retraction of GW compact binary merger candidate
  89. LIGO/Virgo S191109d: AstroSat CZTI upper limits
  90. LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
  91. LIGO/Virgo S191109d: upper limits from AGILE-GRID observations mailed-by:
  92. LIGO/Virgo S191109d: Upper limits from Fermi-GBM Observations
  93. LIGO/Virgo S191109d: Upper limits from IceCube neutrino searches
  94. LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo S191105e: AstroSat CZTI upper limits
  96. LIGO/Virgo S191105e: Not observable by CALET
  97. LIGO/Virgo S191105e : no neutrino counterpart candidate in ANTARES search
  98. LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
  99. LIGO/Virgo S191105e: upper limits from AGILE/GRID observations
  100. LIGO/Virgo S191105e: Upper limits from Fermi-GBM Observations

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