Sidebands to mHz QPOs in 4U 1626$-$67 in the second spin-down state

Rahul Sharma, Chetana Jain, Biswajit Paul +1

We report results from an $AstroSat$ Target-of-Opportunity (ToO) observation of 4U 1626$-$67, performed on 2023 May 18, soon after the discovery of torque reversal to spin-down in…