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arXiv 0704.0267astro-ph
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黑洞X射线双星A0620-00的近红外光谱

Near-Infrared Spectra of the Black Hole X-Ray Binary, A0620-00

C. S. Froning, E. L. Robinson, M. A. Bitner

摘要:

我们提供了A0620-00在IRTF上用SpeX获得的宽带近红外光谱。光谱的特点是由一个蓝色的连续叠加宽发射线的HI和HeII和主机较窄的吸收线的中性金属和分子。光谱型标准恒星的光谱,若以A0620-00去红化的K光谱为标准,则所有光谱型K7 V或更早的恒星的光谱,都超过了A0620-00的J和H光谱,这表明施主星,除非晚于K7 V,否则不可能是A0620-00中唯一的近红外辐射源。此外,K3 V光谱中的原子吸收线相对于A0620-00来说太弱,即使在100%的施主星贡献下,也限制了A0620-00中施主星的光谱类型晚于K3 V。A0620-00光谱与K星光谱的比较表明,A0620-00的CO吸收特征明显弱于场矮星。Roche叶填充施主星的标度模型光谱与A0620-00光谱的拟合表明,当C丰度降低到[C/H] =-1.5时,CO吸收线得到最佳匹配。H波段施主星贡献为82 ± 2%。结合Froning & Robinson(2001)和Marsh et al.(1994)先前发表的结果,这给出了A0620-00中黑洞的精确质量M_BH = 9.7+-0.6 M_solar。

英文摘要:

We present broadband NIR spectra of A0620-00 obtained with SpeX on the IRTF. The spectrum is characterized by a blue continuum on which are superimposed broad emission lines of HI and HeII and a host of narrower absorption lines of neutral metals and molecules. Spectral type standard star spectra scaled to the dereddened spectrum of A0620-00 in K exceed the A0620-00 spectrum in J and H for all stars of spectral type K7V or earlier, demonstrating that the donor star, unless later than K7V, cannot be the sole NIR flux source in A0620-00. In addition, the atomic absorption lines in the K3V spectrum are too weak with respect to those of A0620-00 even at 100% donor star contribution, restricting the spectral type of the donor star in A0620-00 to later than K3V. Comparison of the A0620-00 spectrum to scaled K star spectra indicates that the CO absorption features are significantly weaker in A0620-00 than in field dwarf stars. Fits of scaled model spectra of a Roche lobe-filling donor star to the spectrum of A0620-00 show that the best match to the CO absorption lines is obtained when the C abundance is reduced to [C/H] = -1.5. The donor star contribution in the H waveband is determined to be 82+-2%. Combined with previous published results from Froning & Robinson (2001) and Marsh et al. (1994), this gives a precise mass for the black hole in A0620-00 of M_BH = 9.7+-0.6 M_solar.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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