Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales

Details Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales

2009-09-10

arxiv.org/abs/0909.2050v2

Astronomy and Astrophysics

Astrophysics

Cosmology and Extragalactic Astrophysics

Accepted by ApJ; 11 pages, 8 figures, 18 online-only figures that can be found at http://physics.ucsb.edu/~ktsoto/online_figs/

Scientific paper

Using longslit, optical spectra of Ultraluminous Infrared Galaxies (ULIRGs), we measure the evolution in the star-formation intensity during galactic mergers. In individual galaxies, we resolve kpc scales allowing comparison of the nucleus, inner disk, and outer disk. We find that the strength of the Hbeta absorption line increases with the projected distance from the center of the merger, typically reaching about 9 Angstrom around 10 kpc. At these radii, the star formation intensity must have rapidly decreased about 300-400 Myr ago; only stellar populations deficient in stars more massive than Type A produce such strong Balmer absorption. In contrast, we find the star formation history in the central kpc consistent with continuous star formation. Our measurements indicate that gas depletion occurs from the outer disk inwards during major mergers. This result is consistent with merger-induced gas inflow and empirically constrains the gas inflow timescale. Numerical simulations accurately calculate the total amount of infalling gas but often assume the timescale for infall. These new measurements are therefore central to modeling merger-induced star formation and AGN activity.

Affiliated with

Also associated with

No associations

Rating

Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stellar Population Gradients in ULIRGs: Implications for Gas Inflow Timescales will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-427611