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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 G275697: INTEGRAL search for a prompt gamma-ray counterpart
  2. LIGO/VIRGO G275697: Fermi GBM Observations
  3. LIGO/Virgo G275697 ANTARES search
  4. LIGO/Virgo G275697: IceCube neutrino observations
  5. LIGO/Virgo G275697: Identification of a GW CBC Candidate
  6. LIGO/Virgo G275404: Keck LRIS classification of MASTER PSN candidate
  7. LIGO/Virgo G275404: REM optical/NIR observations
  8. LIGO/Virgo G275404: Fermi-LAT search for a high-energy gamma-ray counterpart
  9. LIGO/Virgo G275404: INTEGRAL search for a prompt gamma-ray counterpart
  10. LIGO/Virgo G275404: AGILE-GRID detection of a possible gamma-ray transient
  11. LIGO/Virgo G275404 ANTARES search
  12. LIGO/Virgo G275404: AGILE-GRID preliminary analysis
  13. LIGO/Virgo G275404: Fermi GBM Observations
  14. LIGO/Virgo G275404: AGILE MCAL observations
  15. LIGO/Virgo G275404: IceCube neutrino observations
  16. LIGO/Virgo G275404: Identification of a GW CBC Candidate
  17. GRB 170222A: Swift-XRT observations
  18. LIGO/Virgo G274296: HAWC follow-up
  19. GRB 170222A: Tiled Swift observations
  20. GRB 170222A: Swift ToO observations
  21. LIGO/Virgo G274296: No change to estimate of LIGO false alarm probability
  22. Swift Trigger 739517 is probably not a GRB
  23. LIGO/Virgo G274296: iPTF Optical Transient Candidates
  24. LIGO/Virgo G274296: Global MASTER Net PSN and QSO detection
  25. LIGO/Virgo G274296: Asiago 1.82m Optical Observations
  26. LIGO/Virgo G274296: IceCube neutrino observations
  27. LIGO/Virgo G274296: Fermi-LAT search for a high-energy gamma-ray counterpart
  28. LIGO/Virgo G274296: AstroSat CZTI upper limits
  29. LIGO/Virgo G274296 ANTARES search
  30. LIGO/Virgo G274296: CNEOST imaging coverage and an optical transient
  31. LIGO/Virgo G274296: Global MASTER Net two OTs detection
  32. LIGO/Virgo G274296: INTEGRAL search for a prompt gamma-ray counterpart
  33. LIGO/Virgo G274296: REM optical/NIR observations
  34. LIGO/VIRGO G274296: Fermi GBM Observations
  35. LIGO/Virgo G274296: Identification of a GW Burst Candidate
  36. Trigger 738728: Swift triggered on noise near NGC 4096
  37. GRB 170214A: NOT optical afterglow confirmation
  38. GRB 170214A: Swift ToO observations
  39. GRB 170209A: Swift ToO observations
  40. GRB 170208B WHT nIR candidate afterglow
  41. GRB 170208B: GROND observations
  42. GRB 170208B: Swift detection of a burst
  43. GRB 170208A: Swift detection of a burst
  44. LIGO/Virgo G270580: ANTARES upper limits
  45. GRB 170206B: Swift detection of a burst
  46. GRB 170205A: Swift detection of a burst with an optical counterpart
  47. GRB 170202A: Swift detection of a burst with an optical afterglow
  48. GRB 170131A: Swift ToO observations
  49. LIGO/Virgo G268556: FLOYDS Spectrum of iPTF17cf/PS17fr Favors an AGN Classification
  50. GRB 170127C: Tiled Swift observations
  51. GRB 170127B: Swift detection of a short burst
  52. GRB 170127A: Swift detection of a burst
  53. GRB 170126A: Swift detection of a burst with an optical counterpart
  54. GRB 170115B: AGILE/SuperAGILE localisation
  55. LIGO/Virgo G270580: No change to estimate of LIGO false alarm probability
  56. LIGO/Virgo G270580: Liverpool Telescope classification of EM candidates
  57. LIGO/Virgo G268556: ANTARES upper limits
  58. GRB 170121B: AbAO optical observations
  59. GRB 170121B: Swift-XRT and UVOT observations
  60. GRB 170121B: Swift ToO observations
  61. LIGO/Virgo G270580: Fermi-LAT search for a high-energy gamma-ray counterpart
  62. LIGO/Virgo G270580: INTEGRAL search of temporally coincident prompt hard X-ray
  63. LIGO/Virgo G268556: Global MASTER Net 21 OTs detection
  64. LIGO/Virgo G270580 ANTARES search
  65. LIGO/Virgo G270580: Identification of a GW Burst Candidate
  66. GRB 170117A: Swift ToO observations
  67. GRB 170115B: Tiled Swift observations
  68. GRB 170115A: Swift detection of a burst
  69. GRB 170113A: Swift detection of a burst with an optical counterpart
  70. LIGO/Virgo G268556: TZAC TAROT network observations with TRE/TCA/TCH
  71. GRB 170112A: REM optical/NIR observations
  72. GRB 170112A: Swift detection of a short burst
  73. LIGO/Virgo G268556: Additional GROWTH follow up observation of iPTF Optical Transient Candidates
  74. LIGO/Virgo G268556/GW170104: Campo Imperatore Observatory observations
  75. GRB 170111A: Swift detection of a burst
  76. LIGO/Virgo G268556: Pan-STARRS1 observations and summary of transient sources
  77. LIGO/Virgo G268556: iPTF Optical Transient Candidates
  78. Swift Trigger 730874 is not astrophysical
  79. LIGO/Virgo G268556: Updated sky map from gravitational-wave data
  80. Swift Trigger 730513 is not an astrophysical event
  81. LIGO/Virgo G268556: ANTARES search
  82. LIGO/Virgo G268556: Fermi GBM Observations
  83. LIGO/Virgo G268556: Identification of a GW CBC Candidate
  84. GRB 161220A: Swift detection of a burst
  85. GRB 161219B: Swift detection of a burst with an optical afterglow
  86. Swift Trigger 727422 is not an astrophysical event.
  87. GRB 161217A: Swift detection of a burst
  88. IceCube-161210: Konus-Wind upper limits
  89. IceCube-161210: CALET Gamma-Ray Burst Monitor upper limits
  90. GRB 161214A: fading optical afterglow candidate with the LT
  91. INTEGRAL SPI-ACS and IBIS/Veto observation of IceCube-161210
  92. IceCube-161210: IceCube observation of a high-energy neutrino candidate event
  93. GRB 161129A: NOT optical observations and candidate host galaxy
  94. GRB 161202A: Swift detection of a burst
  95. GRB 160821B: HST detection of the optical and IR counterpart
  96. GRB 161129A: Swift detection of a burst
  97. GRB 161123A: Tiled Swift observations
  98. Swift Trigger 723124 is probably not a GRB
  99. Swift Trigger 722681 is probably not a GRB
  100. GRB 161117B: Swift detection of a burst

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