A B lue Tilt in the G lobular C luster System ofthe M ilky W ay-like G alaxy N G C 5170

A B ST R A C T HerewepresentHST/ACS im aging,in theB and Ibands,oftheedge-on Sb/Scgalaxy NGC 5170.Excluding the centraldisk region region,we detect a 142 objects with coloursand sizestypicalofglobularclusters(GCs).Ourm ain resultisthe discovery ofa ‘blue tilt’(a m ass-m etallicity relation),at the 3� level,in the m etal-poor GC subpopulation ofthis M ilky W ay like galaxy.The tilt is consistent with that seen in m assive ellipticalgalaxiesand with the selfenrichm entm odelofBailin & Harris.