▁event : ▁the ▁e jection ▁of ▁a ▁super mass ive ▁black ▁hole ▁from ▁the ▁center ▁of ▁the ▁host ▁galax y . ▁In ▁this ▁interpretation , ▁one ▁of ▁the ▁emission ▁line ▁systems ▁origin ates ▁in ▁gas ▁that ▁is ▁bound ▁to ▁the ▁black ▁hole , ▁while ▁the ▁other ▁set ▁is ▁associated ▁with ▁gas ▁that ▁remains ▁in ▁the ▁galax y . ▁ ▁Ev idence ▁for ▁a ▁re co iling ▁black ▁hole ▁A ▁team ▁led ▁by ▁Stef anie ▁Kom ossa ▁of ▁the ▁Max ▁Plan ck ▁Institute ▁for ▁Ext r ater rest rial ▁Physics ▁carried ▁out ▁the ▁analysis . ▁Two ▁systems ▁of ▁strong ▁emission ▁lines ▁were ▁identified ▁in ▁the ▁optical ▁spectrum ▁of ▁this ▁qu as ar . ▁The ▁first , ▁or ▁" red ", ▁system ▁consists ▁of ▁narrow ▁lines ▁of ▁[ O ▁III ] ▁and ▁other ▁ion ized ▁elements ▁at ▁a ▁red shift ▁of ▁z = 0 . 7 1 2 . ▁Such ▁lines ▁are ▁normally ▁associated ▁with ▁gas ▁far ▁from ▁the ▁center ▁of ▁a ▁galax y , ▁which ▁is ▁being ▁excited ▁by ▁emission ▁from ▁the ▁central ▁qu as ar . ▁The ▁second , ▁or ▁" blue ", ▁system ▁consists ▁of ▁broad ▁emission ▁lines , ▁the ▁kind ▁that ▁are ▁generally ▁associated ▁with ▁hot ▁gas ▁very ▁close ▁to ▁the ▁super mass ive ▁black ▁hole ; ▁these ▁lines ▁are ▁at ▁a ▁red shift ▁of ▁ 0 . 6 9 7 . ▁The ▁velocity ▁difference ▁between ▁the ▁two ▁emission ▁line ▁systems ▁is ▁ 2 6 5 0   km / s . ▁ ▁This ▁puzz ling ▁observation ▁is ▁most ▁naturally ▁explained