Hubble Space Telescope Observations of the Large Magellanic Cloud Field around SN 1987A: Distance Determination with Red Clump and Tip of the Red Giant Branch Stars
Hubble Space Telescope Observations of the Large Magellanic Cloud Field around SN 1987A: Distance Determination with Red Clump and Tip of the Red Giant Branch Stars
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哈勃太空望远镜对 SN 1987A 周围大麦哲伦云场的观测：利用红巨星分支星的红团簇和尖端确定距离
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发表时间：
1999
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通讯作者：
Usa
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作者：
M. Romaniello;M. Salaris;S. Cassisi;Nino Panagia Eso;Garching;Germany Liverpool John Moores University;Liverpool;Uk;Osservatorio Astronomico di Collurania;Teramo;Italy;Mpa;Germany;STScI;Baltimore;Usa
我们利用哈勃空间望远镜（HST）WFPC 2多波段观测大麦哲伦星云中SN 1987 A周围的一个场，测量它与太阳的距离。这些观测使我们能够仔细地确定沿着视线到大量恒星的星际消光，并通过使用两个恒星距离指示器来测量LMC距离：红色团块（RC）和红巨星分支的尖端（TRGB）。应用红团方法，我们得到了（m-M）= 18.59 ± 0.04 ± 0.08mag（统计加系统误差）的距离模，这与用TRGB星得到的距离（m-M）= 18.69 ± 0.25 ± 0.06mag（统计加系统误差）是一致的。这两个值都与SN 1987 A的距离一致，如从其内环荧光回波的研究中确定的[（m-M）SN 1987 A = 18.55 ± 0.05 mag]，因此排除了低于18.43的距离模量至99.7%的显著性水平。与以前的结果使用相同的距离指标的差异进行了讨论。
We have used Hubble Space Telescope (HST) WFPC2 multiband observations of a field around SN 1987A in the Large Magellanic Cloud to measure its distance from the Sun. The observations allowed us to carefully determine the interstellar extinction along the line of sight to a large number of stars and to measure the LMC distance by using two stellar distance indicators: the red clump (RC) and the tip of the red giant branch (TRGB). From an application of the red clump method, we obtain a distance modulus of (m - M) = 18.59 ± 0.04 ± 0.08 mag (statistical plus systematic error), in good agreement with the distance derived by using the TRGB stars, namely, (m - M) = 18.69 ± 0.25 ± 0.06 mag (statistical plus systematic error). Both values agree well with the distance to SN 1987A as determined from a study of its inner ring fluorescent echo [(m - M)SN 1987A = 18.55 ± 0.05 mag], thus excluding distance moduli lower than 18.43 to a 99.7% significance level. Differences with respect to previous results obtained using the same distance indicators are discussed.