2001A&A...370..365T


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.08CET02:01:04

2001A&A...370..365T - Astronomy and Astrophysics, volume 370, 365-383 (2001/5-1)

Multi-method-modeling of interacting galaxies. I. A unique scenario for NGC 4449?

THEIS C. and KOHLE S.

Abstract (from CDS):

NGC 4449 is an active star-forming dwarf galaxy of Magellanic type. From radio observations, van Woerden et al. (1975, in La Dynamique de Galaxies Spirales, ed. L. Weliachew, 483) found an extended HI-halo around NGC 4449 which is at least a factor of 10 larger than the optical diameter D25≃5.6kpc. Recently, Hunter et al. (1998ApJ...495L..47H) discerned details in the HI-halo: a disc-like feature around the center of NGC 4449 and a lopsided arm structure. We combined several N-body methods in order to investigate the interaction scenario between NGC 4449 and DDO 125, a close companion in projected space. In a first step fast restricted N-body models are used to confine a region in parameter space reproducing the main observational features. In a second step a genetic algorithm is applied for a uniqueness test of our preferred parameter set. We show that our genetic algorithm reliably recovers orbital parameters, provided that the data are sufficiently accurate, i.e. all the key features are included. In the third step the results of the restricted N-body models are compared with self-consistent N-body simulations. In the case of NGC 4449, the applicability of the simple restricted N-body calculations is demonstrated. Additionally, it is shown that the HI gas can be modeled here by a purely stellar dynamical approach. In a series of simulations, we demonstrate that the observed features of the extended HI disc can be explained by a gravitational interaction between NGC 4449 and DDO 125. According to these calculations the closest approach between both galaxies happened ∼4-6x108yr ago at a minimum distance of ∼25kpc on a parabolic or slightly elliptic orbit. In the case of an encounter scenario, the dynamical mass of DDO 125 should not be smaller than 10% of NGC 4449's mass. Before the encounter, the observed HI gas was arranged in a disc with a radius of 35-40kpc around the center of NGC 4449. It had the same orientation as the central ellipsoidal HI structure. The origin of this disc is still unclear, but it might have been caused by a previous interaction.

Abstract Copyright:

Journal keyword(s): galaxies: interactions - galaxies: kinematics and dynamics - individual: NGC 4449, DDO 125 - methods: N-body simulations - methods: data analysis

Simbad objects: 10

goto Full paper

goto View the reference in ADS

Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 3077 GiP 10 03 19.0965510921 +68 44 01.556166166 11.23 10.85 10.14 9.74   ~ 699 0
2 NGC 4038 GiP 12 01 53.002 -18 52 03.32   10.91   9.74 11.0 ~ 1285 1
3 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1573 0
4 NGC 4039 GiP 12 01 53.8 -18 53 06   11.08   9.77   ~ 1136 1
5 UGC 7577 GiG 12 27 41.8803124881 +43 29 58.140216428 13.75 13.10 12.7 12.33   ~ 232 0
6 NGC 4449 EmG 12 28 11.118 +44 05 36.81 10.11 9.98 9.64 9.45   ~ 1036 1
7 M 94 SyG 12 50 53.148 +41 07 12.55 9.15 8.96 8.24 7.78   ~ 1247 3
8 M 51 GiP 13 29 52.698 +47 11 42.93   9.26 8.36 8.40   ~ 3893 4
9 NGC 5195 GiP 13 29 59.590 +47 15 58.06 10.76 10.45 9.55 9.31   ~ 712 3
10 MCG-01-60-021 LIN 23 41 47.285 -03 40 01.90 14.88 14.50 13.57     ~ 84 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2001A&A...370..365T and select 'bookmark this link' or equivalent in the popup menu


2021.03.08-02:01:04

© Université de Strasbourg/CNRS

    • Contact