Interstellar titanium in the galactic halo

Abstract

view Abstract Citations (20) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interstellar Titanium in the Galactic Halo Lipman, Keith ; Pettini, Max Abstract We present observations of Ti~II~$\lambda 3384$ absorption towards 15 distant stars in the Galactic halo and the Magellanic Clouds. These new data extend existing surveys of the distribution of Ti$^+$ to larger distances from the plane of the Galaxy than sampled previously, allowing the scale height of titanium to be determined for the first time. We find $h_{Ti^+} = 1.5 \pm 0.2$~kpc, a value which although greater than those of other tracers of neutral gas, is not as large as had been suspected. We interpret the extended distribution of Ti$^+$ as an indication that its severe depletion in interstellar clouds in the disk is reduced at the lower densities prevailing in the halo. The data are consistent with a simple power-law dependence of the Ti abundance on the ambient density, with exponent $k \simeq -1$. If the model is correct, it implies that refractory elements like Ti are fully returned to the gas phase at distances beyond $\sim 1$ kpc from the plane of the Galaxy. Publication: The Astrophysical Journal Pub Date: April 1995 DOI: 10.1086/175466 arXiv: arXiv:astro-ph/9410074 Bibcode: 1995ApJ...442..628L Keywords: Absorption Spectra; Galactic Halos; Interstellar Gas; Magellanic Clouds; Milky Way Galaxy; Titanium; Ultraviolet Astronomy; Ultraviolet Spectra; Abundance; Astronomical Spectroscopy; Density (Number/Volume); Scale Height; Spectrum Analysis; Astronomy; GALAXIES: MAGELLANIC CLOUDS; GALAXY: HALO; ISM: ABUNDANCES; Astrophysics E-Print: Accepted for publication in ApJ, due to appear 1 April 1995. 23 pages including 5 figures full text sources arXiv | ADS | data products SIMBAD (17)