DARK MATTER SUBSTRUCTURE DETECTION USING SPATIALLY RESOLVED SPECTROSCOPY OF LENSED DUSTY GALAXIES
- Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada)
- Astronomy Department, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801 (United States)
- Theoretical Astrophysics Center, University of California, Berkeley, CA 94720 (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- CITA, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)
- California Institute of Technology, 1200 East California Blvd, MC 249-17, Pasadena, CA 91125 (United States)
We investigate how strong lensing of dusty, star-forming galaxies (DSFGs) by foreground galaxies can be used as a probe of dark matter halo substructure. We find that spatially resolved spectroscopy of lensed sources allows dramatic improvements to measurements of lens parameters. In particular, we find that modeling of the full, three-dimensional (angular position and radial velocity) data can significantly facilitate substructure detection, increasing the sensitivity of observables to lower mass subhalos. We carry out simulations of lensed dusty sources observed by early ALMA (Cycle 1) and use a Fisher matrix analysis to study the parameter degeneracies and mass detection limits of this method. We find that even with conservative assumptions, it is possible to detect galactic dark matter subhalos of {approx}10{sup 8} M{sub Sun} with high significance in most lensed DSFGs. Specifically, we find that in typical DSFG lenses, there is a {approx}55% probability of detecting a substructure with M > 10{sup 8} M{sub Sun} with more than 5{sigma} detection significance in each lens, if the abundance of substructure is consistent with previous lensing results. The full ALMA array, with its significantly enhanced sensitivity and resolution, should improve these estimates considerably. Given the sample of {approx}100 lenses provided by surveys such as the South Pole Telescope, our understanding of dark matter substructure in typical galaxy halos is poised to improve dramatically over the next few years.
- OSTI ID:
- 22167462
- Journal Information:
- Astrophysical Journal, Vol. 767, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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