GECKOS | Science

The GECKOS Survey

^* Generalising Edge-on galaxies and their Chemical bimodalities, Kinematics, and Outflows out to Solar environments

Our primary focus is determining the relative importance between internal and external physical processes that drive the evolution of disk galaxies. GECKOS will deliver spatially resolved measurements of stellar abundances, ages, and kinematics, as well as ionised gas metallicities, ionisation parameters, pressure, and inflow and outflow kinematics; all key parameters for building a complete chemodynamical picture of disk galaxies.

Goals

Our science goals are focused on answering outstanding questions around three major themes:

1. History and Impact of External Processes: What is the effect of mergers on bulges and on the vertical structure of disks? Can the chemical bimodality in galaxies be explained through accretion alone?

2. History and Impact of Internal Processes: Are thick disks the remnants of a turbulent, clumpy, gas-rich phase in galaxies at redshift = 2? How important is radial migration for thick disks? What is the role of outflows and Galactic fountains in altering galaxy chemistry?

3. Synthesis - Chemodynamical Models: Can the Milky Way be used as a template for disk evolution? What is the predictive power of Galactic chemical evolution models to explain the properties of L∗ disk galaxies?

The sample

The GECKOS survey is a systematic study of 35 edge-on disk galaxies with MUSE IFS, going out to larger radius, deeper (S/N> 40 at μ = 23.5 mag/arcsec2), and with higher spatial resolution (<200 pc) than existing IFS surveys. Targets are selected from the S4G survey (66%, Sheth et al. 2010) and HyperLEDA (34%, Makarov et al. 2014) within a distance range of 15 < D < 70Mpc. We specifically target edge-on (i > 85^◦) galaxies with a stellar mass within ±0.3 dex of the Milky Way.

Sample Selection

GECKOS contains 35 edge-on galaxies with Milky Way stellar masses, selected from three SFR bins to probe a diverse range of assembly histories.

Comparing GECKOS with other IFS surveys

GECKOS moves deep single- object studies to controlled samples, utilising a largely unprobed observational parameter space (right panel; survey statistics from Sanchez, 2020).