Australian authorities have charged two women with offences related to slavery after they returned from Syria, where they had been detained in a refugee camp for more than seven years. The women, aged 53 and 31, face crimes against humanity charges including owning and using ​a slave in Syria, which carry a maximum penalty of 25 years in prison. ​They were arrested at Melbourne airport upon their arrival. Thirteen women and children with alleged ties to Isis returned to Australia years after the collapse of the extremist group’s caliphate. Several women and children arrived in Melbourne on Thursday night, while another woman travelling with her child landed separately in Sydney. Authorities moved quickly after their arrival, charging the two women in Melbourne. Separately, a 32-year-old Australian woman was arrested at Sydney airport on Thursday and charged with terror-related offences, including allegedly joining Isis.…