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arXiv 1003.5634astro-ph.CO
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星暴星系NGC 6000中一氧化碳发射的成像

Imaging Carbon Monoxide Emission in the Starburst Galaxy NGC 6000

Sergio Martin, Matthew R. George, David J. Wilner, Daniel Espada

摘要:

我们目前的测量一氧化碳排放的中心区域附近的星暴NGC 6000采取的亚毫米阵列。12 CO、13 CO和C_(18)O的J=2-1跃迁的图像分辨率为~ 3“× 2”(450 × 300 pc)。我们精确地确定了NGC 6000的动力学中心R.A(J2000.0)= 15 h 49 m 49.5s和dec(J2000.0)=-29d 23“13”,这与分子发射峰的位置相一致。所观察到的CO动力学可以解释的背景下,存在一个酒吧潜在的影响分子材料,可能负责强核浓度超过85%的气体位于。我们检测到一个运动学分离的组成部分,致密的分子气体在相对较高的速度,这可能是燃料的恒星形成。得出的总核动力学质量为7 × 10^9 Msun,总气体质量为4.6 × 10^8 Msun,Mgas/Mdyn约为6%,与先前研究的其他具有中心星暴的棒星系相似。我们用光学薄同位素C18 O测定了分子气体的质量,并估算出CO到H2的转换因子X(CO)=0.4x10^20 cm-2/(K km s-1),这与在其他星暴星系中测定的结果一致。

英文摘要:

We present measurements of carbon monoxide emission in the central region of the nearby starburst NGC 6000 taken with the Submillimeter Array. The J=2-1 transition of 12CO, 13CO, and C18O were imaged at a resolution of ~3''x2'' (450x300 pc). We accurately determine the dynamical center of NGC 6000 at R.A(J2000.0)=15h49m49.5s and dec(J2000.0)=-29d23'13'' which agrees with the peak of molecular emission position. The observed CO dynamics could be explained in the context of the presence of a bar potential affecting the molecular material, likely responsible for the strong nuclear concentration where more than 85% of the gas is located. We detect a kinematically detached component of dense molecular gas at relatively high velocity which might be fueling the star formation. A total nuclear dynamical mass of 7x10^9 Msun is derived and a total mass of gas of 4.6x10^8 Msun, yielding a Mgas/Mdyn~6%, similar to other previously studied barred galaxies with central starbursts. We determined the mass of molecular gas with the optically thin isotopologue C18O and we estimate a CO-to-H2 conversion factor X(CO)=0.4x10^20 cm-2/(K km s-1) in agreement with that determined in other starburst galaxies.

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