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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"

16286 results found.

  1. LIGO/Virgo S191216ap: Nanshan follow-up observations
  2. LIGO/Virgo S191216ap: IceCube event: MASTER OF detection in GW and Neutrino error field
  3. LIGO/Virgo S191213g: MASTER OT J064855.37-055545.7 is a dwarf nova
  4. UKIRT photometry of ZTF19acyldun/AT 2019wrt
  5. LIGO/Virgo S191213g: LCOGT photometry of ZTF19acymaru/AT2019wnh
  6. LIGO/Virgo S191213g: WHT spectroscopy of candidate counterparts
  7. LIGO/Virgo S191213g: GRAWITA TNG classification of ZTF19acykzsk
  8. LIGO/Virgo S191213g: Liverpool Telescope spectroscopy of ZTF candidates
  9. LIGO/Virgo S191205ah: AT2019wix and AT2019wib 10.4m GTC spectroscopy
  10. LIGO/Virgo S191205ah: AT2019wkv, AT2019wid and AT2019wiy 10.4m GTC spectroscopy
  11. GRB 191213A: BOOTES-5/JGT optical limit
  12. LIGO/Virgo S191205ah: AT2019wfa 10.4m GTC spectroscopy
  13. LIGO/Virgo S191205ah: MASTER OT 1.5m OSN imaging and 10.4m GTC spectroscopy
  14. LIGO/Virgo S191205ah: MITSuME Observation of MASTER OT J123123.61-043847.2
  15. LIGO/Virgo S191205ah: GMG detection of SAGUARO transient
  16. LIGO/Virgo S191205ah: SAGUARO observations and identification of an optical candidate
  17. GRB 191004A: correction to reported GROND upper limits
  18. GRB 191125B: MASTER-VWFC synchronous observation
  19. GRB 191123A: iTelescope optical upper limits
  20. GRB 191123A: Swift/UVOT detection
  21. GRB 191123A: Swift detection of a burst with an optical counterpart
  22. GRB 191122A: Swift/UVOT Upper Limits
  23. GRB 191122A: BOOTES-4/MET optical limit
  24. GRB 191122A: CHES Optical Observations
  25. LIGO/Virgo S191110af: Upper limits from KM3NeT MeV neutrino search.
  26. LIGO/Virgo S191110af: Evryscope observation report, no counterpart candidates
  27. GRB 191106A: Swift/UVOT Upper Limits
  28. GRB 191106A: NOT optical upper limit
  29. GRB 191106A: Mondy optical upper limit
  30. GRB 191106A: BOOTES-4/MET optical limit
  31. GRB 191106A: MASTER optical observation
  32. GRB191016A GROND observations
  33. Swift GRB191105.01: Global MASTER-Net OT detection
  34. GRB 191101A: Swift/UVOT Upper Limits
  35. GRB 191031D: Gemini optical upper limit
  36. GRB 191101A: iTelescope optical limit
  37. GRB 191101A: VIRT Optical Upper Limits
  38. GRB 191031D: MMT Binospec Optical Upper Limit
  39. GRB 191031D: Swift/UVOT Upper Limits
  40. GRB 191031D: MITSuME Akeno optical upper limits
  41. GRB 191031D: COATLI Optical Observations
  42. GRB 191031D: RATIR Optical and NIR Observations
  43. GRB 191031A: COATLI Optical Observations
  44. GRB 191019A: Zadko Telescope optical observations
  45. GRB 191029A: Swift/UVOT Upper Limits
  46. GRB 191028B: MASTER optical observation
  47. GRB 191029A: BOOTES-4/MET optical limit
  48. GRB 191029A: iTelescope optical upper limits
  49. GRB 191023A: MASTER optical observation
  50. Possible GRB 191025A: FRAM-Auger optical limit
  51. GRB 191024A: Swift/UVOT Upper Limits
  52. GRB 191024A: VLT/X-shooter optical observations
  53. GRB191024A: MASTER optical observation
  54. GRB 191019A: NOT optical afterglow and host association confirmation
  55. GRB 191019A: Nanshan-0.6m optical observations
  56. GCN Circ. 26044 and 26047 are mistakenly submission GRB reports
  57. Swift GRB191020.81: Global MASTER-Net OT detection
  58. GRB 191019A: NOT optical spectroscopy of candidate counterpart
  59. GRB 191019A: NOT optical observations
  60. GRB 191019A: TSHAO optical observations, probable afterglow and host galaxy
  61. GRB 191019A: MASTER optical observation
  62. GRB 191017B: Swift/UVOT Upper Limits
  63. GRB 191016A: REM optical observations
  64. GRB 191016A: Swift/UVOT Detection
  65. GRB191016A: MITSuME Okayama optical observation
  66. GRB 191016A: AZT-20 (Assy observatory) optical photometry
  67. GRB 191016A: early time BOOTES Network and follow-up 1.5m OSN optical observations
  68. GRB 191016A: RATIR Optical and NIR Observations
  69. GRB 191016A: Optical limit by Ondrejov D50
  70. GRB 191016A: KAIT Optical Afterglow Confirmation
  71. GRB 191016A: COATLI Optical Observations and Detection of the Afterglow
  72. ANTARES 191011A: MASTER optical observation befor and after trigger
  73. GRB 191011A: Swift/UVOT Detection
  74. GRB 191011A: RATIR Optical and NIR Observations
  75. GRB 19011A: Optical Afterglow Detection with LCO
  76. GRB 191011A: MASTER OT retraction.
  77. GRB 191011A: GROND Detection of the Optical/NIR afterglow
  78. GRB 191011A: VLT X-shooter redshift from RRM Observations
  79. Swift GRB191011.19: Global MASTER-Net OT detection
  80. GRB 191011A: Swift detection of a burst with an optical counterpart
  81. LIGO/Virgo S190930t: Continued Swift observations of AT2019sbk
  82. TESS Detection of the Optical Emission from the Possible Untriggered GRB Associated with ZTF19abvizsw
  83. GRB 191004B: Continued Optical Afterglow Monitoring with LCO
  84. GRB 191004A: Optical Detection with LCO
  85. GRB 190928A: AstroSat CZTI detection
  86. LIGO/Virgo S190930t: Swift J221951-484240 optical photometry of Chilescope observatory
  87. LIGO/Virgo S190930t: SALT optical spectroscopy of Swift J221951-484240
  88. GRB 191004B: GROND Detection of the Optical/NIR Afterglow
  89. GRB 191004B: COATLI Optical Observations
  90. GRB 191004B: VLT/X-shooter redshift
  91. GRB 191004B: NOT optical photometry
  92. GRB 191004A: NOT optical upper limits
  93. GRB 191004B: Optical Afterglow Detection with LCO
  94. Swift GRB191004.9: Global MASTER-Net OT detection
  95. GRB 191004B: Swift detection of a burst with an optical counterpart
  96. GRB 191004A: Swift detection of a burst with an optical detection
  97. Swift GRB191004.75: Global MASTER-Net OT detection
  98. LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
  99. GRB 191001A: Swift-XRT observations
  100. LIGO/Virgo S190930t: J-GEM follow-up observation for Swift J221951-484240

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