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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"
  1. LIGO/Virgo G268556: optical observations and classification of Pan-STARRS1 transients
  2. LIGO/Virgo G268556: BSA radio observations at 110 MHz
  3. LIGO/Virgo G268556/GW170104: Konus-Wind observations
  4. GRB 170527A: Fermi GBM detection
  5. GRB 170526A, Swift-BAT refined analysis
  6. GRB 170526A: Swift/UVOT Upper Limits
  7. GRB 170526A: Swift-XRT refined Analysis
  8. LIGO/Virgo G268556: VERITAS Very-High-Energy Gamma-Ray Observations
  9. GRB 170524A: RATIR Optical and NIR Observations
  10. GRB 170526A: Enhanced Swift-XRT position
  11. GRB 170524B: Swift-XRT observations
  12. GRB 170526A: Swift detection of a burst
  13. Konus-Wind observation of GRB 170524B
  14. GRB 170524B: MASTER-OAFA observations
  15. GRB 170511A CALET Gamma-Ray Burst Monitor detection
  16. GRB 170524A: TSHAO and CrAO optical observations
  17. GRB 170524B: Swift ToO observations
  18. GRB 170524A: Swift-BAT refined analysis
  19. GRB 170524B: Swift detection of a burst
  20. GRB 170524A: Swift/UVOT Upper Limits
  21. GRB 170524A: D50 optical observation and limit
  22. GRB 170524A: Swift-XRT refined Analysis
  23. IPN Triangulation of GRB 170522A
  24. GRB 170511A: MAXI/GSC detection
  25. GRB 170524A: Enhanced Swift-XRT position
  26. GRB 170524A: Swift detection of a burst (or possible new SGR)
  27. GRB 170522A: LCO McDonald observations
  28. GRB 170522A: Swift-XRT observations
  29. GRB 170522A: Global MASTER-Net job
  30. Konus-Wind observation of GRB 170522B
  31. IPN Triangulation of GRB 170522B (long/intense)
  32. Konus-Wind observation of GRB 170522A
  33. GRB 170522A: Tiled Swift observations
  34. GRB 170522A: Fermi-LAT detection
  35. GRB 170522A: Fermi GBM detection
  36. GRB 170514A CALET Gamma-Ray Burst Monitor detection
  37. GRB 170519A: MITSuME Akeno Optical Observation
  38. GRB 170519A: Watcher optical observations
  39. GRB 170519A: Continued RATIR Optical and NIR Observations
  40. GRB 170519A: MITSuME Okayama Optical Observation
  41. GRB 170519A: NOT optical observations
  42. GRB 170519A: Redshift from GTC/OSIRIS
  43. GRB170519A, Swift-UVOT Detection
  44. GRB 170519A: BOOTES-5/JGT early optical detection
  45. LIGO/Virgo G284239: DLT40 follow-up observation
  46. GRB 170519A: KAIT Optical Observations
  47. GRB 170519A: Swift-XRT refined Analysis
  48. GRB 170519A: iTelescope T11 optical observations
  49. GRB 170519A: Swift-BAT refined analysis
  50. GRB 170519A: Weihai optical observations
  51. GRB 170510A: LCO Siding Springs early observations
  52. GRB 170519A: RATIR Optical and NIR Observations
  53. GRB 170519A: optical observations
  54. GRB 170519A: Enhanced Swift-XRT position
  55. GRB 170519A: Swift detection of a burst with an optical counterpart
  56. GRB 170510A CALET Gamma-Ray Burst Monitor detection
  57. LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
  58. GRB 170510A: Swift-XRT afterglow detection
  59. GRB 170516A: Swift-BAT refined analysis
  60. GRB 170516A: Swift-XRT refined Analysis
  61. AXP CXOU J164710.2-455216: Fermi GBM observation
  62. GRB 170516A: Swift/UVOT Upper Limits
  63. GRB 170516A: Enhanced Swift-XRT position
  64. GRB 170516A: Swift detection of a burst
  65. Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
  66. Swift Trigger on AXP CXOU J164710.2-455216
  67. GRB 170514A: Fermi GBM detection
  68. GRB 170510A: AstroSat CZTI(Veto) detection
  69. Fermi GBM trigger 516459580/170514541 is not a GRB
  70. GRB 170510A: Global MASTER Net possible OT observations
  71. Konus-Wind observation of GRB 170510A
  72. LIGO/Virgo G275404 and G275659: SkyMapper Follow-up Observations
  73. LIGO/Virgo G284239: Konus-Wind observations
  74. GRB 170510A: LCO possible counterpart
  75. GRB 170510A: Swift-XRT observations
  76. GRB 170510A: Fermi GBM observation
  77. LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
  78. LIGO/Virgo G284239: MAXI/GSC observations
  79. GRB 170510A: Tiled Swift observations
  80. GRB 170510A: Fermi-LAT detection
  81. Swift Trigger 752193 is not a GRB
  82. LIGO/Virgo G284239: AstroSat CZTI upper limits
  83. Trigger 751928: Swift misidentification of Cen X-3
  84. GRB 170423A: TAROT Reunion observatory optical observations
  85. IceCube-170506A - IceCube update on a high-energy neutrino candidate event
  86. Swift XRT observations of GRB 170424A
  87. LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
  88. LIGO/VIRGO G284239: Fermi GBM Upper Limits
  89. LIGO/Virgo G284239: HAWC follow-up
  90. LIGO/Virgo G284239: MASTER automatic follow up and synchronous observations
  91. LIGO/Virgo G284239: Fermi-LAT search for a high-energy gamma-ray counterpart
  92. LIGO/Virgo G284239: TZAC TAROT network observations with TRE/TCA/TCH
  93. GRB 170428A CALET Gamma-Ray Burst Monitor detection
  94. LIGO/Virgo: G284239 ANTARES search
  95. LIGO/Virgo G284239: Swift/BAT data search
  96. LIGO/Virgo G284239: AGILE GRID observations
  97. LIGO/Virgo G284239: INTEGRAL search for a prompt gamma-ray counterpart
  98. LIGO/Virgo G284239: AGILE MCAL Observations
  99. LIGO/Virgo G284239: IceCube neutrino observations
  100. LIGO/Virgo G284239: Identification of a GW Burst Candidate

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