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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"

19549 results found.

  1. LIGO/Virgo S191215w : no neutrino counterpart candidate in ANTARES search
  2. LIGO/Virgo S191215w: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  3. IceCube-191215A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  4. LIGO/Virgo S191213g: GMOS-N spectroscopy shows ZTF19acykzsk/AT2019wqj is a SN II
  5. LIGO/Virgo S191213g: No neutrino candidates at Pierre Auger Observatory
  6. LIGO/Virgo S191213g: No counterpart candidates in Fermi-LAT observations
  7. LIGO/Virgo S191213g: no counterpart candidates in the Swift/BAT observations
  8. LIGO/Virgo S191213g : no neutrino counterpart candidate in ANTARES search
  9. LIGO/Virgo S191213g: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  10. LIGO/Virgo S191204r: correction to GRAWITA GCN 26390
  11. Possible HAWC-detected GRB 191210A: Fermi-LAT Upper Limits
  12. Possible HAWC-detected GRB 191210A: no neutrino counterpart candidate in ANTARES search
  13. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL transient candidates discovery.
  14. LIGO/Virgo S191205ah: no counterpart candidate in SVOM/GWAC observations
  15. LIGO/Virgo S191205ah : No significant candidates in FRAM - TAROT – GRANDMA observations
  16. LIGO/Virgo S191205ah: MASTER OT 1.5m OSN imaging and 10.4m GTC spectroscopy
  17. LIGO/Virgo S191204r: GRAWITA VST-ESO PARANAL observations.
  18. IceCube-191204A: No significant detection in HAWC
  19. LIGO/Virgo S191205ah: No neutrino candidates at Pierre Auger Observatory
  20. LIGO/Virgo S191205ah: no counterpart candidates in the Swift/BAT observations
  21. LIGO/Virgo S191205ah: No counterpart candidates in Fermi-LAT observations
  22. LIGO/Virgo S191129u : No significant candidates in FRAM-TAROT-GRANDMA observations.
  23. LIGO/Virgo S191204r: No significant candidates in FRAM-TAROT-GRANDMA observations.
  24. LIGO/Virgo S191205ah: SAGUARO observations and identification of an optical candidate
  25. LIGO/Virgo S191204r: No counterpart candidates in Fermi-LAT observations
  26. LIGO/Virgo S191205ah: No counterpart candidates in HAWC observations
  27. LIGO/Virgo S191205ah : no neutrino counterpart candidate in ANTARES search
  28. LIGO/Virgo S191205ah: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  29. LIGO/Virgo S191205ah: Identification of a GW compact binary merger candidate
  30. LIGO/Virgo S191204r: no counterpart candidates in the Swift/BAT observations
  31. IceCube-191204A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  32. LIGO/Virgo S191204r : no neutrino counterpart candidate in ANTARES search
  33. LIGO/Virgo S191204r: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  34. GRB 191130A: Swift ToO observations
  35. GRB 191004A: correction to reported GROND upper limits
  36. LIGO/Virgo S191129u: No counterpart candidates in Fermi-LAT observations
  37. LIGO/Virgo S191129u: Swift/BAT in SAA
  38. LIGO/Virgo S191129u: No counterpart candidates in HAWC observations
  39. LIGO/Virgo S191129u : no neutrino counterpart candidate in ANTARES search
  40. GRB 191125B: MASTER-VWFC synchronous observation
  41. IceCube-191122A: No significant detection in HAWC
  42. GRB 191123A: Swift/UVOT further analysis
  43. GRB 191123A: Enhanced Swift-XRT position
  44. GRB 191123A: iTelescope optical upper limits
  45. GRB 191123A: Swift/UVOT detection
  46. GRB 191123A: Swift detection of a burst with an optical counterpart
  47. GRB 191122A: Swift/UVOT Upper Limits
  48. GRB 191122A: Enhanced Swift-XRT position
  49. GRB 191122A: Swift detection of a burst
  50. IceCube-191119A: No significant detection in HAWC
  51. IceCube-191119A: Upper limits from a search for additional neutrino events in IceCube
  52. Fermi-LAT Gamma-ray Observations of IceCube-191119A
  53. IceCube-191119A - No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  54. Swift Trigger 937114 is not an astrophysical source
  55. LIGO/Virgo S191110af: Potential pulsar counterparts
  56. LIGO/Virgo S191110af: Swift XRT observations, no secure afterglow found
  57. LIGO/Virgo S191110af: no counterpart candidates in the Swift/BAT observations
  58. LIGO/Virgo S191110af: No neutrino counterpart candidate in ANTARES search
  59. LIGO/Virgo S191110af: No counterpart candidates in Fermi-LAT observations
  60. LIGO/Virgo S191110af: Evryscope observation report, no counterpart candidates
  61. LIGO/Virgo S191110af: No counterpart candidates in INTEGRAL SPI-ACS, prompt observation
  62. LIGO/Virgo S191109d: No counterpart candidates in Fermi-LAT observations
  63. LIGO/Virgo S191109d: no counterpart candidates in the Swift/BAT observations
  64. LIGO/Virgo S191109d : no neutrino counterpart candidate in ANTARES search
  65. LIGO/Virgo S191109d: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
  66. GRB 191108A: Fermi GBM Final Real-time Localization
  67. GRB 191106A: Swift/UVOT Upper Limits
  68. LIGO/Virgo S191105e: No counterpart candidates in Fermi-LAT observations
  69. LIGO/Virgo S191105e: no counterpart candidates in the Swift/BAT observations
  70. GRB 191106A: NOT optical upper limit
  71. GRB 191106A: Swift-XRT refined Analysis
  72. LIGO/Virgo S191105e : no neutrino counterpart candidate in ANTARES search
  73. LIGO/Virgo S191105e: No counterpart candidates in HAWC observations
  74. LIGO/Virgo S191105e: No counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
  75. GRB 191106A: Mondy optical upper limit
  76. GRB 191106A: Swift detection of a burst
  77. GRB191016A GROND observations
  78. GRB 191101A: Swift/UVOT Upper Limits
  79. SGR 1935+2154: Swift-BAT refined analysis
  80. GRB 191031D: Gemini optical upper limit
  81. GRB 191101A: iTelescope optical limit
  82. GRB 191101A: VIRT Optical Upper Limits
  83. GRB 191101A: Enhanced Swift-XRT position
  84. GRB 191101A: Swift detection of a burst
  85. GRB 191031D: MMT Binospec Optical Upper Limit
  86. GRB 191031A: Swift-BAT refined analysis
  87. GRB 191031D: Swift/UVOT Upper Limits
  88. GRB 191031C: Swift/UVOT Detection
  89. GRB 191031D: COATLI Optical Observations
  90. GRB 191031D: RATIR Optical and NIR Observations
  91. GRB 191031D: Enhanced Swift-XRT position
  92. GRB 191031C: Enhanced Swift-XRT position
  93. GRB 191031D: Swift detection of a short hard burst
  94. GRB 191031C: Swift detection of a burst
  95. GRB 191031A: COATLI Optical Observations
  96. Konus-Wind observation of GRB 191027A
  97. GRB 191029A: Swift/UVOT Upper Limits
  98. GRB 191029A: Enhanced Swift-XRT position
  99. GRB 191029A: BOOTES-4/MET optical limit
  100. GRB 191029A: iTelescope optical upper limits

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