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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"

7445 results found.

  1. LIGO/Virgo G288732: Fermi GBM Upper Limits for the LIGO Trigger and LAT Candidate
  2. LIGO/Virgo G288732: Pan-STARRS coverage of the Fermi/LAT candidate position
  3. Swift trigger 758168 is probably not an astrophysical source
  4. LIGO/Virgo G288732: VLA imaging of the possible Fermi/LAT counterpart
  5. Swift Trigger 756953 is probably not an astrophysical source
  6. LIGO/Virgo G288732: HAWC follow-up
  7. LIGO/Virgo G288732: UKIRT near-IR imaging of the Fermi/LAT candidate
  8. LIGO/Virgo G288732: LBT optical imaging of the Fermi/LAT candidate
  9. LIGO/Virgo G288732: Updated sky map from gravitational-wave data
  10. LIGO/Virgo G288732: GWFUNC/NOWT observations of the skymap and follow-up of the Fermi/LAT candidate
  11. LIGO/Virgo G288732: INTEGRAL search for a prompt gamma-ray counterpart
  12. LIGO/Virgo G288732: Fermi-LAT detection of a weak candidate
  13. LIGO/Virgo G288732: IceCube neutrino observations update
  14. LIGO/Virgo G288732 ANTARES search
  15. LIGO/VIRGO G288732: Fermi GBM Observations
  16. LIGO/Virgo G288732: Identification of a GW Binary Merger Candidate
  17. GRB 170607A: NOT optical afterglow detection
  18. GRB 170607A: Swift detection of a burst with a bright optical counterpart
  19. GRB 170604A: GTC spectroscopic redshift
  20. Swift Trigger 755873: a possible GRB
  21. GRB 170531A: Swift/UVOT Observations
  22. GRB 170531B: Swift detection of a burst
  23. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  24. GRB 170526A: Swift detection of a burst
  25. GRB 170524B: Swift ToO observations
  26. GRB 170524A: Swift detection of a burst (or possible new SGR)
  27. GRB 170522A: Tiled Swift observations
  28. GRB 170510A: LCO Siding Springs early observations
  29. GRB 170519A: Swift detection of a burst with an optical counterpart
  30. GRB 170510A: Global MASTER Net possible OT observations
  31. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  32. GRB 170510A: LCO possible counterpart
  33. GRB 170510A: Tiled Swift observations
  34. IceCube-170506A - IceCube update on a high-energy neutrino candidate event
  35. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  36. LIGO/Virgo G284239: Fermi-LAT search for a high-energy gamma-ray counterpart
  37. LIGO/Virgo: G284239 ANTARES search
  38. LIGO/Virgo G284239: INTEGRAL search for a prompt gamma-ray counterpart
  39. LIGO/Virgo G284239: AGILE MCAL Observations
  40. LIGO/Virgo G284239: IceCube neutrino observations
  41. LIGO/Virgo G284239: Identification of a GW Burst Candidate
  42. GRB 170428A: GTC spectroscopic redshift of candidate host galaxy
  43. LIGO/Virgo G268556: Refined localization from CBC parameter estimation
  44. GRB 170428A: TNG optical observations
  45. GRB 170428A: DCT Imaging
  46. GRB 170428A: RATIR Afterglow Confirmation
  47. GRB 170428A: Xinglong 2.16-m upper limit and host galaxy candidate
  48. Swift Trigger 750337 is probably a noise fluctuation
  49. GRB 170428A: Swift detection of a short burst
  50. Swift trigger 750096 - OT candidate
  51. Swift Trigger 750096 is probably a noise fluctuation
  52. Swift Trigger 750044 is probably a noise fluctuation
  53. GRB 170424A: Tiled Swift observations
  54. Swift Trigger 748858: RATIR Optical and NIR Observations
  55. GRB 170419A: Swift detection of a burst
  56. Swift Trigger 748858: a possible GRB
  57. Trigger 745966: Swift detection of 4U1850-03
  58. GRB 170405A: Swift detection of a burst with an optical counterpart
  59. LIGO/Virgo G275697: Update on significance from offline analyses
  60. LIGO/Virgo G275404: Update on significance from offline analyses
  61. IceCube-170321A: Konus-Wind upper limits
  62. Swift Trigger 745090 is a noise trigger near NGC 5195
  63. Fermi-LAT Gamma-ray Observations of IceCube-170321
  64. Swift triggered on SAX J1806.5-221
  65. IceCube-170321A: Swift-XRT observations
  66. GRB 170331A: Swift detection of a burst
  67. GRB 170330A: Swift detection of a burst
  68. LIGO/Virgo G277583: INTEGRAL search for an X-ray and gamma-ray counterpart
  69. LIGO/Virgo G275697: AMI Large Array Search for a Radio Afterglow
  70. IceCube-170321A - IceCube observation of a high-energy neutrino candidate event
  71. INTEGRAL SPI-ACS observation of AMON IceCube EHE 80305071 129307
  72. Search for counterpart to IceCube-170321A with ANTARES
  73. GRB 170318B: Swift detection of a burst
  74. GRB 170318A: Swift detection of a burst
  75. IceCube-170312A: MASTER follow-up observations
  76. GRB 170317A: Swift detection of a burst with an optical counterpart
  77. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  78. LIGO/Virgo G275404: Medicina radio follow-up of near-infrared
  79. LIGO/Virgo G277583 ANTARES search
  80. LIGO/Virgo G277583: AGILE MCAL observations
  81. LIGO/Virgo G277583: IceCube neutrino observations
  82. LIGO/Virgo G277583: Identification of a GW Burst Candidate
  83. IceCube-170312A - IceCube update on a high-energy neutrino candidate event
  84. INTEGRAL observation of IceCube HESE 65274589 129281
  85. GRB 170311A: Swift detection of a burst
  86. GRB 170306A: GROND afterglow detection
  87. LIGO/Virgo G275404: Updated localization from LIGO data
  88. LIGO/Virgo G275697: Updated localization from LIGO data
  89. GRB 170306B: Tiled Swift observations
  90. GRB 170306A: Swift detection of a burst
  91. LIGO/Virgo G275697: Liverpool Telescope classification of EM candidates
  92. LIGO/Virgo G275697: Additional iPTF Optical Transient Candidates
  93. LIGO/Virgo G275404: Additional iPTF Optical Transient Candidates
  94. LIGO/Virgo G275697: iPTF Optical Transient Candidates
  95. LIGO/Virgo G275404: iPTF Optical Transient Candidates
  96. LIGO/Virgo G275404: Fermi GBM Upper Limits
  97. LIGO/Virgo G275404: A near-infrared transient in the error circle of AGL J1914+1043
  98. LIGO/Virgo G275697: Fermi-LAT search for a high-energy gamma-ray counterpart
  99. LIGO/Virgo G275697: REM optical/NIR observations
  100. LIGO/Virgo G275697: AGILE MCAL Observations

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