THE DEPENDENCE OF GALACTIC OUTFLOWS ON THE PROPERTIES AND ORIENTATION OF zCOSMOS GALAXIES AT z∼ 1

We present an analysis of cool outflowing gas around galaxies, traced by Mg-II absorption lines in the coadded spectra of a sample of 486 zCOSMOS galaxies at 1 <= z <= 1.5. These galaxies span a range of stellar masses (9.45 <= log(10)[M-*/M-circle dot] <= 10.7) and star formation rates (0.14 <= log(10)[SFR/M-circle dot yr(-1)] <= 2.35). We identify the cool outflowing component in the Mg (II) absorption and find that the equivalent width of the outflowing component increases with stellar mass. The outflow equivalent width also increases steadily with the increasing star formation rate of the galaxies. At similar stellar masses, the blue galaxies exhibit a significantly higher outflow equivalent width as compared to red galaxies. The outflow equivalent width shows strong correlation with the star formation surface density (Sigma(SFR)) of the sample. For the disk galaxies, the outflow equivalent width is higher for the face-on systems as compared to the edge-on ones, indicating that for the disk galaxies, the outflowing gas is primarily bipolar in geometry. Galaxies typically exhibit outflow velocities ranging from -150 km s(-1) similar to -200 km s(-1) and, on average, the face-on galaxies exhibit higher outflow velocity as compared to the edge-on ones. Galaxies with irregular morphologies exhibit outflow equivalent width as well as outflow velocities comparable to face on disk galaxies. These galaxies exhibit mass outflow rates >5-7 M-circle dot yr(-1) and a mass loading factor (eta = (M) over dot(out)/SFR) comparable to the star formation rates of the galaxies.