Baryonic Distributions in the Dark Matter Halo of NGC5005

TL;DR

This study combines multiwavelength observations of NGC5005 to analyze its gas, stars, and dark matter distribution, revealing a significant dark matter component influencing its rotation curve.

Contribution

It provides a detailed mass decomposition of NGC5005 using new HI, ionized gas, and infrared data, highlighting the dark matter's role in galaxy dynamics.

Findings

The HI disk exhibits a flat rotation curve from 20 to 140 arcseconds.

The stellar disk extends much farther than the gas disk, with a transition at 1.6 times the gas extent.

Dark matter contributes significantly to the galaxy's rotation at all radii.

Abstract

We present results from multiwavelength observations of the galaxy NGC5005. We use new neutral hydrogen (HI) observations from the Very Large Array to examine the neutral gas morphology and kinematics. We find an HI disk with a well-behaved flat rotation curve in the radial range 20\arcsec-140\arcsec. Ionized gas observations from the SparsePak integral field unit on the WIYN 3.5m telescope provide kinematics for the central 70\arcsec. We use both the SparsePak and HI velocity fields to derive a rotation curve for NGC5005. Deep 3.6{\mu}m observations from the Spitzer Space Telescope probe the faint extended stellar population of NGC5005. The images reveal a large stellar disk with a high surface brightness component that transitions to a low surface brightness component at a radius nearly 1.6 times farther than the extent of the gas disk detected in HI. The 3.6{\mu}m image is also decomposed into bulge and disk components to account for the stellar light distribution. Optical broadband B and R and narrowband H{\alpha} from the WIYN 0.9m telescope complement the 3.6{\mu}m data by providing information about the dominant stellar population and current star formation activity. The neutral and ionized gas rotation curve is used along with the stellar bulge and disk light profiles to decompose the mass distributions in NGC5005 and determine a dark matter halo model. The maximum stellar disk contribution to the total rotation curve is only about 70\%, suggesting that dark matter makes a significant contribution to the dynamics at all radii.