The CIV-MgII Kinematics Connection in <z>~0.7 Galaxies

TL;DR

This study reveals a strong link between MgII and CIV absorption features and galaxy kinematics at z~0.7, suggesting interconnected processes involving outflowing gas, star formation, and halo ionization conditions.

Contribution

It provides the first detailed correlation analysis between MgII kinematics and CIV absorption in galaxies at intermediate redshift, highlighting the connection between halo gas properties and galaxy stellar populations.

Findings

Strong correlation between MgII kinematics and CIV absorption strength.

No ionization gradient observed with galactocentric distance.

Tentative anti-correlation between CIV/MgII ratio and galaxy color.

Abstract

We have examined Faint Object Spectrograph data from the Hubble Space Telescope Archive for CIV 1548,1550 absorption associated with 40 MgII 2796,2803 absorption-selected galaxies at 0.4 < z < 1.4. We report a strong correlation between MgII kinematics, measured in 6 km/s resolution HIRES/Keck spectra, and W_r(1548); this implies a physical connection between the processes that produce "outlying velocity" MgII clouds and high ionization galactic/halo gas. We found no trend in ionization condition, W_r(1548)/W_r(2796), with galaxy-QSO line-of-sight separation for 13 systems with confirmed associated galaxies, suggesting no obvious ionization gradient with galactocentric distance in these higher redshift galaxies. We find tentative evidence (2-sigma) that W_r(1548)/W_r(2796) is anti-correlated with galaxy <B-K> color; if further data corroborate this trend, in view of the strong CIV-MgII kinematics correlation, it could imply a connection between stellar populations, star formation episodes, and the kinematics and ionization conditions of halo gas at z~1.