arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1402.5545astro-ph.GAastro-ph.CO
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早型镓中粉尘和电离气体的研究

Study of Dust and Ionized gas in Early-type Galaxies

Samridhi Kulkarni, D. K. Sahu, Laxmikant Chaware, N. K. Chakradhari, S. K. Pandey

摘要:

我们提出的结果,光学宽带和窄带Halpha观测的样本附近的40个早型星系。已知大多数样本星系都有各种形式的尘埃,即尘埃带、核尘埃和斑块状/颗粒状尘埃。对12个具有突出尘埃特征的星系进行了详细的尘埃研究。这些星系的消光曲线与银河系的消光曲线平行,这意味着这些星系中的尘埃的性质与银河系相似。总消光与选择性消光之比(Rv)在2.1和3.8之间变化,平均值为2.9 +/- 0.2,相当接近我们银河系的典型值3.1。这些<a>星系中尘埃粒子的平均相对粒度/a_Gal为1.01 +/- 0.2,而使用光学消光估计的尘埃质量在10^2到10^4 M(太阳)之间。在通过窄带滤光片拍摄的29个星系中,有23个星系检测到了H α辐射,其亮度范围为10^38 - 10^41 erg·s^-1。电离气体的质量在10^3-10^5 M(太阳)之间。电离气体的形态和范围与尘埃相似,表明这些星系中可能存在尘埃和电离气体。蓝色光度和归一化的IRAS尘埃质量之间没有任何明显的相关性,这暗示了这些星系中尘埃和气体的合并相关起源。

英文摘要:

We present results of optical broad-band and narrow-band Halpha observations of a sample of forty nearby early-type galaxies. The majority of sample galaxies are known to have dust in various forms viz. dust lanes, nuclear dust and patchy/filamentary dust. A detailed study of dust was performed for 12 galaxies with prominent dust features. The extinction curves for these galaxies run parallel to the Galactic extinction curve, implying that the properties of dust in these galaxies are similar to those of the Milky-Way. The ratio of total to selective extinction (Rv) varies between 2.1 and 3.8, with an average of 2.9 +/- 0.2, fairly close to its canonical value of 3.1 for our Galaxy. The average relative grain size <a>/a_Gal of dust particles in these galaxies turns out to be 1.01 +/- 0.2, while dust mass estimated using optical extinction lies in the range 10^2 to 10^4 M(sun) . The Halpha emission was detected in 23 out of 29 galaxies imaged through narrow- band filters with the Halpha luminosities in the range 10^38 - 10^41 erg s^-1. The mass of the ionized gas is in the range 10^3-10^5 M(sun). The morphology and extent of ionized gas is found similar to those of dust, indicating possible coexistence of dust and ionized gas in these galaxies. The absence of any apparent correlation between blue luminosity and normalized IRAS dust mass is suggestive of merger related origin of dust and gas in these galaxies.

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