Two Somerville police officers have been recognized by the city for their response to the Boston Marathon bombings. Officers Patrick Canty and Katherine Costa were both off duty, celebrating Patriots Day among the crowd near the finish line when the bombs went off. Canty and his cousin, former Somerville firefighter Sean Layton, used belts, T-shirts, and shoelaces as makeshift tourniquets for victims, and threw victims over their shoulders to carry them to safety. Costa applied gauze and a tourniquet to a man with a serious foot injury. Canty and Costa were given citations of commendation by the Somerville Board of Aldermen last Thursday.