We report on a systematic investigation of the cold and mildly ionized gaseous baryonic metal components of our Galaxy , through the analysis of high resolution Chandra and XMM- Newton spectra of two samples of Galactic and extragalactic sources .
The comparison between lines of sight towards sources located in the disk of our Galaxy and extragalactcic sources , allows us for the first time to clearly distinguish between gaseous metal components in the disk and halo of our Galaxy .
We find that a Warm Ionized Metal Medium ( WIMM ) permeates a large volume above and below the Galaxy ’ s disk , perhaps up to the Circum-Galactic space ( CGM ) .
This halo-WIMM imprints virtually the totality of the OI and OII absorption seen in the spectra of our extragalactic targets , has a temperature of T _ { WIMM } ^ { Halo } = 2900 \pm 900 K , a density < n _ { H } > _ { WIMM } ^ { Halo } = 0.023 \pm 0.009 cm ^ { -3 } and a metallicity Z _ { WIMM } ^ { Halo } = ( 0.4 \pm 0.1 ) Z _ { \odot } .
Consistently with previous works , we also confirm that the disk of the Galaxy contains at least two distinct gaseous metal components , one cold and neutral ( the CNMM : Cold Neutral Metal Medium ) and one warm and mildly ionized , with the same temperature of the halo-WIMM , but higher density ( < n _ { H } > _ { WIMM } ^ { Disk } = 0.09 \pm 0.03 cm ^ { -3 } ) and metallicity ( Z _ { WIMM } ^ { Disk } = 0.8 \pm 0.1 Z _ { \odot } ) .
By adopting a simple disk+sphere geometry for the Galaxy , we estimates masses of the CNMM and the total ( disk + halo ) WIMM of M _ { CNMM } { { } _ { < } \atop { } ^ { \sim } } 8 \times 10 ^ { 8 } M _ { \odot } and M _ { WIMM } \simeq 8.2 \times 10 ^ { 9 } M _ { \odot } .