The SWELLS Survey. I. A large spectroscopically selected sample of edge-on late-type lens galaxies

Understand

The relative contribution of baryons and dark matter to the inner regions of spiral galaxies provides critical clues to their formation and evolution, but it is generally difficult to determine.

• For spiral galaxies that are strong gravitational lenses, however, the combination of lensing and kinematic observations can be used to break the disk-halo degeneracy.
• In turn, such data constrain fundamental parameters such as i) the mass density profile slope and axis ratio of the dark matter halo, and by comparison with dark matter-only numerical simulations the modifications imposed by baryons; ii) the mass in stars and therefore the overall star formation efficiency, and the amount of feedback; iii) by comparison with stellar population synthesis models, the normalization of the stellar initial mass function.
• In this first paper of a series, we present a sample of 16 secure, 1 probable, and 6 possible strong lensing spiral galaxies, for which multi-band high-resolution images and rotation curves were obtained using the Hubble Space Telescope and Keck-II Telescope as part of the Sloan WFC Edge-on Late-type Lens Survey (SWELLS).