A near-infrared survey of Miras and the distance to the Galactic Centre
A near-infrared survey of Miras and the distance to the Galactic Centre
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DOI：
10.1111/j.1365-2966.2009.15393.x
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发表时间：
2009-07
期刊：
影响因子：
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通讯作者：
N. Matsunaga;T. Kawadu;S. Nishiyama;T. Nagayama;H. Hatano;M. Tamura;I. Glass;Tetsuya Nagata University of Tokyo;K. University;Nagoya University;National Space Development Agency of Japan;South African astronomical Observatory
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文献类型：
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作者：
N. Matsunaga;T. Kawadu;S. Nishiyama;T. Nagayama;H. Hatano;M. Tamura;I. Glass;Tetsuya Nagata University of Tokyo;K. University;Nagoya University;National Space Development Agency of Japan;South African astronomical Observatory
我们报告了对银河系中心(GC)20角分乘30角分视场内长周期变星的近红外探测结果。我们已经检测到1364个变量，其中348个与Glass等人报告的一致。(2001年)。我们给出了探测到的变星的星表和光度测量，并讨论了它们的性质。我们还建立了一种利用JHKs波段的周期-光度关系同时估计距离和消光的方法。我们的方法适用于周期在100-350d范围内，平均星等在两个或更多个滤波带内的MIRAS。虽然J波段的平均值通常不适用于我们的天体，但我们估计了143个水星的距离和灭绝，它们的H波段和Ks波段的平均星等都是得到的。我们发现，大多数都位于相同的距离，在我们的准确度之内。假定这些水星的重心对应于GC，我们估计其距离模数为14.58±-0.02(统计)+-0.11(系统)。Mag，对应8.24+-0.08(统计)+-0.42(系统)KPC。我们假设到LMC的距离模数为18.45毫微克，这个量的不确定度包括在上面的系统误差中。我们还讨论了大灭绝和高度可变的灭绝。除了较厚的暗星云外，A(Ks)的值从1.5毫克到大于4毫克不等，并且它随视线的变化而复杂。我们已经在Ramirez等人的Spitzer/IRAC目录中确定了中红外对应物。(2008)，并且发现它们在3.6至8.0微米波长范围内遵循相当窄的周期-光度关系。
We report the results of a near-infrared survey for long-period variables in a field of view of 20 arcmin by 30 arcmin towards the Galactic Centre (GC). We have detected 1364 variables, of which 348 are identified with those reported in Glass et al. (2001). We present a catalogue and photometric measurements for the detected variables and discuss their nature. We also establish a method for the simultaneous estimation of distances and extinctions using the period-luminosity relations for the JHKs bands. Our method is applicable to Miras with periods in the range 100--350 d and mean magnitudes available in two or more filter bands. While J-band means are often unavailable for our objects because of the large extinction, we estimated distances and extinctions for 143 Miras whose H- and Ks-band mean magnitudes are obtained. We find that most are located at the same distance to within our accuracy. Assuming that the barycentre of these Miras corresponds to the GC, we estimate its distance modulus to be 14.58+-0.02(stat.)+-0.11(syst.) mag, corresponding to 8.24+-0.08(stat.)+-0.42(syst.) kpc. We have assumed the distance modulus to the LMC to be 18.45 mag, and the uncertainty in this quantity is included in the systematic error above. We also discuss the large and highly variable extinction. Its value ranges from 1.5 mag to larger than 4 mag in A(Ks) except towards the thicker dark nebulae and it varies in a complicated way with the line of sight. We have identified mid-infrared counterparts in the Spitzer/IRAC catalogue of Ramirez et al. (2008) for most of our variables and find that they follow rather narrow period-luminosity relations in the 3.6 to 8.0 micrometre wavelength range.