Yelena Bonner, the Russian rights activist and widow of the Nobel peace prize winner Andrei Sakharov, has died aged 88.

Bonner died of heart failure on Saturday afternoon in Boston, according to her daughter, Tatiana Yankelevich. She had been in hospital since February, Yankelevich said.

Bonner grew famous through her marriage to Sakharov, the Soviet Union’s leading dissident, but she carved out her own reputation as a tireless human rights campaigner in the face of relentless hostility from Soviet authorities.

Bonner and Sakharov’s cramped three-room apartment in Moscow was the unofficial headquarters of the Soviet dissident movement in the 1970s, and again in the late 1980s after they returned from internal exile in the city of Gorky.

Both suffered constant harassment, and Soviet officialdom regularly made caustic, personal attacks against Bonner, accusing her of being a foreign agent who had bullied her husband, the father of the Soviet atomic bomb, into turning against his country.

The attacks only seemed to strengthen their resolve, and neither stopped calling for greater personal freedom for Soviet citizens.

“I hope to live out my life until the end worthy of the Russian culture in which I’ve spent my life, of the Jewish and Armenian nationalities, and I am proud that mine has been the difficult lot and happy fate to be the wife and friend of academic Andrei Dmitrievich Sakharov,” Bonner wrote in her autobiography.