MUltiwavelength observations of the Structure, Chemistry, and Evolution of LSB galaxies
Jason E. Young    Rachel Kuzio de Naray    Sharon X. Wang

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The MUSCEL Program
Low surface brightness (LSB) disk galaxies are formally defined as having B-band surface brightnesses fainter than 22 mag arcsec-2. They span the same range of baryonic masses as their high surface brightness (HSB) counterparts, yet for reasons not fully understood, they have largely retained their atomic gas instead of producing stars. They are characterized by their gas-richness, low gas surface densities, low past and current star formation rates, blue colors, and low metal abundances. Their kinematics are dominated by dark matter down to small radii and their dark matter halos are cored.

Why do LSB galaxies seem to have followed a different evolutionary path than their HSB counterparts? Why do they have so few stars? What are their star formation histories? Could they have had the bursts of star formation that have been proposed to change the structure of their dark matter halos?

To answer these questions, we have begun the MUSCEL (MUltiwavelength observations of the Structure, Chemistry and Evolution of LSB galaxies) program. Using ground-based optical IFU spectra and space-based UV and IR photometry, our goal is to fully constrain the spatially-resolved star formation histories of an initial sample of 10 LSB galaxies. Our targets span 3 decades in Vflat and ~4 decades in stellar and gas mass, allowing us to study the population of LSB disk galaxies as a whole, across a wide range of mass. We anticipate producing maps of log (O/H) metallicity, star formation, and extinction, as well as SEDs for each target. We will also model the photometric and kinematic structure of each galaxy. These results combined with rotation curves and mass models in the literature will provide the most comprehensive analysis of a sample of LSB galaxies yet available.

Check this page frequently for updates on the status of MUSCEL and to download available data products!


New Results
UGC 628 shows evidence for both inside-out and outside-in star formation! What is going on? Read our latest paper to find out more.
Figure 7 from Young et al. (2015): The lower branch metallicities (blue triangles) show a positive gradient consistent with outside-in star formation, while the U-V color gradient (black crosses) is negative, consistent with inside-out star formation.

Latest News
02/02/2017: MUSCEL posters presented at the 2017, 2016 and 2014 AAS Winter Meetings are now online
06/30/2015: Paper on UGC 628 published in MNRAS
06/24/2015: Paper on UGC 628 accepted for publication in MNRAS

1. "The Distribution of Star Formation and Metals in the Low Surface Brightness Galaxy UGC 628"
     Young, J.E., Kuzio de Naray, R., & Wang, S.X. 2015, MNRAS, 452, 2973
     (astro-ph) (MNRAS)

Posters about the MUSCEL galaxies were presented at the 2017 Winter AAS Meeting in Austin:
Posters from the 2016 and 2014 Winter AAS Meetings in Kissimmee and Washington, D.C.:

Data Products
• Properties of HII Regions in UGC 628: Table 2 of Young, Kuzio de Naray, & Wang 2015, MNRAS, 452, 2973