By Makiko Yamazaki and Leika Kihara TOKYO, Jan 26 (Reuters) - The unusual rate check by the New York Federal Reserve that triggered a spike in the stubbornly weak yen has lowered the threshold for intervention, but coordinated Japan-U.S. selling of dollars still looks highly unlikely at this stage. The Fed's action late on Friday was the strongest signal to date that Japanese ​and U.S. authorities were working closely together to stem the currency's decline, keeping markets on high alert for intervention ...