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arXiv · 2209.14134

Orientation effects on cool gas absorption from gravitational-arc tomography of a z = 0.77 disc galaxy

A. Fernandez-Figueroa·S. Lopez·N. Tejos·T. A. M. Berg·C. Ledoux·P. Noterdaeme·A. Afruni·L. F. Barrientos·J. Gonzalez-Lopez·M. Hamel·E. J. Johnston·A. Katsianis·K. Sharon·M. Solimano
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Abstract

We use spatially-resolved spectroscopy of a distant giant gravitational arc to test orientation effects on MgII absorption equivalent width (EW) and covering fraction (kappa) in the circumgalactic medium of a foreground star-forming galaxy (G1) at z~0.77. Forty-two spatially-binned arc positions uniformly sample impact parameters (D) to G1 between 10 and 30 kpc and azimuthal angles alpha between 30 and 90 degrees (minor axis). We find an EW-D anti-correlation, akin to that observed statistically in quasar absorber studies, and an apparent correlation of both EW and kappa with alpha, revealing a non-isotropic gas distribution. In line with our previous results on MgII kinematics suggesting the presence of outflows in G1, at minimum a simple 3-D static double-cone model (to represent the trace of bipolar outflows) is required to recreate the EW spatial distribution. The D and alpha values probed by the arc cannot confirm the presence of a disc, but the data highly disfavor a disc alone. Our results support the interpretation that the EW-alpha correlation observed statistically using other extant probes is partly shaped by bipolar metal-rich winds.

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A. Fernandez-Figueroa, S. Lopez, N. Tejos, T. A. M. Berg, C. Ledoux, P. Noterdaeme, A. Afruni, L. F. Barrientos, J. Gonzalez-Lopez, M. Hamel, E. J. Johnston, A. Katsianis, K. Sharon, M. Solimano. 2022-09-28. Orientation effects on cool gas absorption from gravitational-arc tomography of a z = 0.77 disc galaxy. https://doi.org/10.1093/mnras%2Fstac2851

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