SIMBAD references

2003AJ....125.2455U - Astron. J., 125, 2455-2472 (2003/May-0)

H I imaging observations of superthin galaxies. I. UGC 7321.

USON J.M. and MATTHEWS L.D.

Abstract (from CDS):

We have used the Very Large Array to image the isolated ``superthin'' galaxy UGC 7321 in the H I line with a spatial resolution of 16" and a spectral resolution of 24 kHz (5.2 km.s–1). We have reached a sensitivity of (0.36-0.40) mJy beam–1 channel–1, which correspond to a column density of (8-9)x1018 atoms cm–2 (1 σ). UGC 7321 has a gas-rich disk, with MHI=(1.06±0.01)x109 d210M and MHI/LB=1.0 (d10 is the distance to UGC 7321 in units of 10 Mpc, the value adopted in this paper), and no detectable radio continuum emission (FCONT=0.41±0.25 mJy). The global H I distribution of UGC 7321 is rather symmetric and extends to ∼1.5 times the optical radius (DHI=8'.65±0'.15 at nHI=3x1019 atoms cm–2). An ``integral sign'' warp is observed in the H I disk, commencing near the edge of the stellar distribution and twisting back toward the equatorial plane in the outermost regions. In addition, the position-velocity diagram suggests the presence of a bar or inner arm within ∼40" from the center. The rotation curve of UGC 7321 is slowly rising; it reaches its asymptotic velocity of ∼110 km.s–1 at ∼2'.5 from the center (about 0.9 optical radii) and declines near the edge of the H I disk. The ratio of the inferred dynamical mass to the mass in gas and stars is ∼12d–110, implying that UGC 7321 is a highly dark-matter-dominated galaxy.

Abstract Copyright:

Journal keyword(s): Galaxies: Individual: Alphanumeric: UGC 7321 - Galaxies: ISM - Galaxies: Kinematics and Dynamics - Galaxies: Spiral - ISM: H I

Simbad objects: 12

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