Speaker
Description
Galaxies are surrounded by diffuse ionized gas, which is often called the circumgalactic medium (CGM) and is the least understood part of galactic ecosystems. The CGM harbors more than 80% of the total baryons in a galaxy, is both the reservoir of gas for subsequent star formation and the depository of chemically processed gas, energy, and angular momentum from feedback, however, we do not yet have a complete map of the CGM for any galaxy. The recent detection of optical emission lines from the CGM in combined, large samples of low-redshift, normal galaxies hints at the potential to map the cool (~10^4 K) CGM in individual local galaxies. Using the integral field unit (IFU) spectra, we present the first source-blind, wide-redshift-range (z ~ 0-5) narrow-band imaging survey for CGM emission. We present >30 kpc wide [O II]λλ3727,3729, Hβ, [O III]λ5007, Hα, [N II]λ6584 emission maps tracing the CGM of a low-mass starburst galaxy (M_*~10^8.6 M_⨀) at a redshift of 0.04723. We also present a 130 kpc wide [O II]λλ3727,3729 feature revealing an interaction between a galaxy pair at z=1.248. The Hα velocity field for the low-mass galaxy suggests that the CGM is more chaotic or turbulent than the galaxy disk, while that for the interacting galaxies shows large-scale coherent motions. We show that deep, integral field spectroscopy can be used to map the CGM of local, normal galaxies and to uncover examples of higher redshift, more dramatic examples of the CGM.
