Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31

Details Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31 Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31

2005-01-13

arxiv.org/abs/astro-ph/0501240v2

Mon.Not.Roy.Astron.Soc. 366 (2006) 996-1011

Astronomy and Astrophysics

Astrophysics

17 pages, 8 color figures, 2 tables. Accepted by Monthly Notices; Models listed in tables modified, text reorganized and short

Scientific paper

10.1111/j.1365-2966.2005.09863.x

This paper is the first in a series which studies interactions between M31 and its satellites, including the origin of the giant southern stream. We construct accurate yet simple analytic models for the potential of the M31 galaxy to provide an easy basis for calculation of orbits in M31's halo. We use an NFW dark halo, an exponential disk, a Hernquist bulge, and a central black hole point mass to describe the galaxy potential. We constrain the parameters of these functions by comparing to existing surface brightness, velocity dispersion, and rotation curve measurements of M31. Our description provides a good fit to the observations, and agrees well with more sophisticated modeling of M31. While in many respects the parameter set is well constrained, there is substantial uncertainty in the outer halo potential and a near-degeneracy between the disk and halo components, producing a large, nearly two-dimensional allowed region in parameter space. We limit the allowed region using theoretical expectations for the halo concentration, baryonic content, and stellar $M/L$ ratio, finding a smaller region where the parameters are physically plausible. Our proposed mass model for M31 has $M_{bulge} = 3.2 \times 10^{10} \Msun$, $M_{disk} = 7.2 \times 10^{10} \Msun$, and $M_{200} = 7.1\times 10^{11} \Msun$, with uncorrected (for internal and foreground extinction) mass-to-light ratios of $M/L_R = 3.9$ and 3.3 for the bulge and disk, respectively. We present some illustrative test particle orbits for the progenitor of the stellar stream in our galaxy potential, highlighting the effects of the remaining uncertainty in the disk and halo masses.

Affiliated with

Also associated with

No associations

Rating

Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31 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 Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Investigating the Andromeda Stream: I. Simple Analytic Bulge-Disk-Halo Model for M31 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-273566