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Дата изменения: Sat Mar 11 12:16:53 2000
Дата индексирования: Sat Sep 11 21:00:07 2010
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Поисковые слова: manicouagan crater

Results and discussion

The main parameters of HS 0822+3542, along with those of the two earlier known local candidate young galaxies, are presented in Table 1.

The distances to all three galaxies for the sake of homogeneity are derived from the radial velocities. For the distance-dependent parameters we used the distances $D_{\rm Vir}$ derived from the quoted heliocentric H I velocities $V_{\rm HI}$, accounting for the Galaxy motion relative to the centroid of the Local Group of 220 km s^-1, for Virgocentric infall (Kraan-Korteweg [1986]), and assuming a Hubble constant H₀ = 75 km s^-1Mpc^-1. Note that HS 0822+3542 is the nearest galaxy among the extremely metal-deficient galaxies shown in Table 1. However, such distance estimates for two galaxies, HS 0822+3542 and I Zw 18 with small radial velocities are rather uncertain. In particular, for I Zw 18 different distance determinations from the literature based on the different observational data, range from 10.9 Mpc to 20 Mpc. To resolve this disagreement the deep HST imaging of I Zw 18 is vital in order to detect the tip of the red giant branch stars and to measure the distance directly. Unfortunately, such observations have not yet been done. The same relates to HS 0822+3542. Keeping in mind this possible source of uncertainty which may change integrated characteristics of HS 0822+3542 and I Zw 18 by a factor of 2-4, we describe below in more detail various parameters of HS 0822+3542 and compare them to other well-known young galaxy candidates.