Query : 2004A&A...413..939V

2004A&A...413..939V - Astronomy and Astrophysics, volume 413, 939-948 (2004/1-3)

Numerical simulations of expanding supershells in dwarf irregular galaxies. I. Application to Holmberg I.


Abstract (from CDS):

Numerical hydrodynamical modelling of supernova-driven shell formation is performed with a purpose to reproduce a giant HI ring (diameter 1.7 kpc) in the dwarf irregular galaxy Holmberg I (Ho I). We find that the contrast in HI surface density between the central HI depression and the ring is sensitive to the shape of the gravitational potential. This circumstance can be used to constrain the total mass (including the dark matter halo) of nearly face-on dwarf irregulars. We consider two models of Ho I, which differ by an assumed mass of the dark matter halo Mh. The contrast in HI surface density between the central HI depression and the ring, as well as the lack of gas expansion in the central hole, are better reproduced by the model with a massive halo of Mh=6.0x109M than by that with a small halo of Mh=4.0x108M, implying that Ho I is halo-dominated. Assuming the halo mass of 6.0x109M, we determine the mechanical energy required to form the observed ring equal to (3.0 ±0.5)x1053 ergs, equivalent 300±50 Type II supernovae. The inclination of Ho I is constrained to 15°-20° by comparing the modelled HI spectrum and channel maps with those observed.

Abstract Copyright:

Journal keyword(s): galaxies: dwarf - individual: Holmberg I = DDO 63 - ISM: bubbles

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 IC 10 G 00 20 25.50 +59 17 17.0   13.6 9.5     ~ 1102 1
2 UGC 4305 IG 08 19 04.9864630512 +70 43 13.086910452 12.06 11.72 11.39 11.11   ~ 755 2
3 UGC 5139 LSB 09 40 32.33 +71 10 56.0 14.53 14.00 13.66 13.41   ~ 350 1
4 NAME M 81-82 Group GrG 09 55 +69.1           ~ 704 0

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