A low-luminosity type-1 QSO sample. IV. Molecular gas contents and conditions of star formation in three nearby Seyfert galaxies
A low-luminosity type-1 QSO sample. IV. Molecular gas contents and conditions of star formation in three nearby Seyfert galaxies
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DOI：
10.1051/0004-6361/201526358
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发表时间：
2016-03
影响因子：
6.5
通讯作者：
L. Moser;M. Krips;G. Busch;J. Scharwaechter;S. Koenig;A. Eckart;S. Smajić;M. Garćia-Maŕin;M. Valencia-S.;S. Fischer;J. Dierkes
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文献类型：
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作者：
L. Moser;M. Krips;G. Busch;J. Scharwaechter;S. Koenig;A. Eckart;S. Smajić;M. Garćia-Maŕin;M. Valencia-S.;S. Fischer;J. Dierkes
我们提出了一项初步研究，利用亚毫米阵列在三个附近的塞弗特星系中对低 CO2 跃迁进行约 3 英寸分辨率的观测，这些星系是低光度准星体 (LLQSO) 样本的一部分，该样本由从汉堡/ESO 准星体 (QSO) 巡天中采集的 99 个附近 (z = 0.06) 1 型活动星系核 (AGN) 组成。在 12CO(2-1) 和 13CO(2-1) 中观察到两个来源，在 12CO(3-2) 和 HCO+(4-3) 中观察到第三个来源。在连续发射中未检测到任何源。检测到的12CO分子气体80%以上集中在直径（FWHM）1.5×109M⊙内，对于Mdust>1.6×106M⊙的尘埃质量。 R21 = 12CO/13CO(2-1)线光度比显示，郊区的星系值为R21 ~ 5-7，中心区域的星系值为R21 ≳ 20，类似于星暴和（超）亮红外星系（（U）LIRGs；即LIRGs和ULIRGs），这意味着更高的温度和更强的湍流。所有三个来源均显示 12CO(2-1)/12CO(1-0) 比率约为 0.5，表明存在冷或扩散气相。引人注目的是，~1 的 12CO(3-2)/(1-0) 比率也表明存在更高的激发相。由于这些星系具有 LIR ≥ 1011L⊙ 的高红外光度，并且似乎包含具有最小气体表面密度和恒星形成率 (SFR) 大约 Σmol = 50-550 M⊙pc-2 和 ΣSFR = 1.1-3.1 M⊙ kpc-2 yr-1 的核周星暴，因此我们得出结论，这些 LIRG Seyferts 中心的星际介质强烈受到剧烈恒星形成的影响，并通过 ULIRG 质量转换因子更好地描述。
We present a pilot study of ~3'' resolution observations of low CO transitions with the Submillimeter Array in three nearby Seyfert galaxies, which are part of the low-luminosity quasi-stellar object (LLQSOs) sample consisting of 99 nearby (z = 0.06) type-1 active galactic nuclei (AGN) taken from the Hamburg/ESO quasi-stellar object (QSO) survey. Two sources were observed in 12CO(2-1) and 13CO(2-1) and the third in 12CO(3-2) and HCO+(4-3). None of the sources is detected in continuum emission. More than 80% of the 12CO detected molecular gas is concentrated within a diameter (FWHM) 1.5 × 109M⊙ and for the dust masses of Mdust> 1.6 × 106M⊙. The R21 = 12CO/13CO(2-1) line luminosity ratios show Galactic values of R21 ~ 5-7 in the outskirts and R21 ≳ 20 in the central region, similar to starbursts and (ultra)luminous infrared galaxies ((U)LIRGs; i.e. LIRGs and ULIRGs), implying higher temperatures and stronger turbulence. All three sources show indications of 12CO(2-1)/12CO(1-0) ratios of ~0.5, suggesting a cold or diffuse gas phase. Strikingly, the 12CO(3-2)/(1-0) ratio of ~1 also indicates a higher excited phase. Since these galaxies have high infrared luminosities of LIR ≥ 1011L⊙ and seem to contain a circumnuclear starburst with minimum surface densities of gas and star formation rate (SFR) around Σmol = 50-550 M⊙pc-2 and ΣSFR = 1.1-3.1 M⊙ kpc-2 yr-1, we conclude that the interstellar medium in the centers of these LIRG Seyferts is strongly affected by violent star formation and better described by the ULIRG mass conversion factor.