Baryon Recycling In Dwarf Galaxies Emission Survey
The central stellar component of dwarf galaxies, where star formation occurs and stellar feedback originates.
BRIDGES targets the circumgalactic medium around these low-mass systems to understand baryon cycling.
The complex process by which gas is expelled from the galaxy and later re-accreted, enriching the circumgalactic medium.
This recycling process is fundamental to understanding how dwarf galaxies evolve over cosmic time.
Hot, metal-enriched gas driven out by supernovae and stellar winds from the central galaxy.
These outflows redistribute metals and regulate star formation efficiency.
The extended gaseous atmosphere surrounding the galaxy, containing a significant fraction of the halo's baryons.
The CGM serves as the interface between the galaxy and the cosmic web, mediating gas flows.
Cold, metal-poor gas streams feeding the galaxy from the cosmic web and intergalactic medium.
These inflows provide the raw material for continued star formation in dwarf systems.
An important question regarding galaxy evolution is how galaxies grow and obtain the fuel needed for star formation. Resolved studies of galaxies have provided an understanding of many processes driving the short term evolution of the interstellar medium, such as star formation, feedback, and chemical enrichment. Far less understood is how these processes depend on, and impact, the baryon cycle: the flow of baryons between a galaxy and its circumgalactic medium (CGM). The CGM contains as much as 50% of a galaxy's baryons and is the interface between star formation processes and a galaxy's gas supply. It is becoming increasingly clear that the long term evolution of galaxies cannot be robustly constrained without characterizing the complex relationships of these interchanging baryonic reservoirs, and how gas is accreted, used, ejected, and recycled.
Dwarf galaxies serve as ideal laboratories for understanding the key components of the baryon cycle: their shallow potential wells make them highly sensitive to stellar feedback processes, and we also expect these low mass galaxies to have low virial temperatures, implying the possibility of a CGM rich in cold accretion, in which cool gas efficiently inflows and settles, perhaps explaining the degree to which nearly all isolated dwarf galaxies are actively star forming.
The Baryon Recycling In Dwarf Galaxies Emission Survey survey (BRIDGES) represents a comprehensive observational campaign to map and characterize the baryon cycle and the missing key in these processes -- the CGM -- in dwarf galaxies. With a combination of high resolution IFU data (Keck/KCWI) and wide field of view, low surface brightness narrowband imaging data (Mothra/Dragonfly), BRIDGES traces the complete baryon cycle: from pristine gas accretion through star formation to metal-enriched outflows and the eventual recycling of processed material back into the galaxy.
Characterize the spatial distribution, ionization, and kinematics of gas around dwarf galaxies using direct emission mapping in Hα, [OIII], and [NII].
Constrain the burstiness of star formation in dwarf galaxies and its impact (or dependence on) the CGM.
Provide observational benchmarks for theoretical models of stellar feedback and its impact on galaxy evolution.
The BRIDGES sample is carefully selected to provide a comprehensive view of dwarf galaxy physics across a range of environments and evolutionary states.
107 - 109 M☉
Covering around SMC to LMC mass galaxies, where we expect low virial temperatures and the settling of cool ionized gas.z < 0.01
-20° - 10°
Local Universe sample, visible Chile (Mothra) and Hawaii (Keck), enabling detailed CGM and internal galaxy characterization.≥ 1.5 Mpc from massive (M* > 109M☉) hosts
Ensuring halo gas has not been stripped as is expected in low mass satellite galaxies.Spatially resolved HI data
Gas rich galaxies where we can cross compare neutral and ionized gas components.