We report a tentative detection of the circumgalactic medium ( CGM ) of WLM , an isolated , low-mass ( log M _ { * } / M _ { \odot } \approx 7.6 ) , dwarf irregular galaxy in the Local Group ( LG ) .
We analyze an HST/COS archival spectrum of a quasar sightline ( PHL2525 ) , which is 45 kpc ( 0.5 virial radius ) from WLM and close to the Magellanic Stream ( MS ) .
Along this sightline , two ion absorbers are detected in Si II , Si III , Si IV , C II , and C IV at velocities of \sim -220 km s ^ { -1 } ( Component v-220 ) and \sim -150 km s ^ { -1 } ( Component v-150 ) .
To identify their origins , we study the position-velocity alignment of the components with WLM and the nearby MS. Near the Magellanic longitude of PHL2525 , the MS-related neutral and ionized gas moves at \lesssim - 190 km s ^ { -1 } , suggesting an MS origin for Component v-220 , but not for Component v-150 .
Because PHL2525 passes near WLM and Component v-150 is close to WLM ’ s systemic velocity ( \sim -132 km s ^ { -1 } ) , it is likely that Component v-150 arises from the galaxy ’ s CGM .
This results in a total Si mass in WLM ’ s CGM of M _ { Si } ^ { CGM } \sim ( 0.2 - 1.0 ) \times 10 ^ { 5 } ~ { } M _ { \odot } using assumption from other COS dwarf studies .
Comparing M _ { Si } ^ { CGM } to the total Si mass synthesized in WLM over its lifetime ( \sim 1.3 \times 10 ^ { 5 } ~ { } M _ { \odot } ) , we find \sim 3 % is locked in stars , \sim 6 % in the ISM , \sim 15 % -77 % in the CGM , and the rest ( \sim 14 % -76 % ) is likely lost beyond the virial radius .
Our finding resonates with other COS dwarf galaxy studies and theoretical predictions that low-mass galaxies can easily lose metals into their CGM due to stellar feedback and shallow gravitational potential .