论文标题
普朗克的尘土飞扬的宝石。 viii。 Z〜3最活跃的尘土飞扬的浓尘库中的密集气库
Planck's Dusty GEMS. VIII. Dense-gas reservoirs in the most active dusty starbursts at z~3
论文作者
论文摘要
我们在三个最明亮的镜头镜头型灰尘型星形的星系中，在Z〜3-3.5的三个最明亮的镜头尘埃星形星系中，对高密度示踪物HCN，HCO+和HNC进行了ALMA，NOEMA和IRAM-30M/EMIR观测，这是Planck的尘土飞扬的尘土飞扬的一部分，以探测与储藏剂的相关级别，以探测它们与它们的相关级别。我们获得了J_UP = 4和6之间的十发射线以及几个额外的通量上限。在PLCK_G244.8+54.9中，是Z = 3.0时最明亮的来源，HNC（5-4）线在0.1英寸时的排放率和其他空间综合的线轮廓，提示密集的分布和更加弥漫的气体储存层，至少在最强大的区域中，该区域均与任何主要的效果相同。我们的样品中的HNC/HCN〜1线比与附近的Ulirgs相似，并且与光子占主导地位的区域一致，而没有任何重要的机械加热或AGN反馈。虽然重要的脱落，但H2密度n〜10^5-6 cm^-3，可以防止确切的条件，这与附近宇宙中的密集气体形成定律的外推一致，这增加了进一步的证据，表明在z〜3中最活跃的星系中观察到的极端星形率是〜3的极端型号。 HCN/[CI]和HCO+/[CI]线的比率升高，但与Z> 2处的其他透镜尘埃形成星系相比，并不是特殊的，并且在局部Ulirgs的上层附近也落下。
We present ALMA, NOEMA, and IRAM-30m/EMIR observations of the high-density tracer molecules HCN, HCO+, and HNC in three of the brightest lensed dusty star-forming galaxies at z~3-3.5, part of the Planck's Dusty GEMS sample, to probe the gas reservoirs closely associated with their exceptional levels of star formation. We obtain robust detections of ten emission lines between J_up=4 and 6, as well as several additional flux upper limits. In PLCK_G244.8+54.9, the brightest source at z=3.0, the HNC(5-4) line emission at 0.1" resolution, together with other spatially-integrated line profiles, suggests comparable distributions of dense and more diffuse gas reservoirs, at least over the most strongly magnified regions. This rules out any major effect from differential lensing. The HCO+/HCN > 1 and HNC/HCN ~ 1 line ratios in our sample are similar to those of nearby ULIRGs and consistent with photon-dominated regions without any indication of important mechanical heating or AGN feedback. We characterize the dense-gas excitation in PLCK_G244.8+54.9 using radiative transfer models assuming pure collisional excitation and find that mid-J HCN, HCO+, and HNC lines arise from a high-density phase with H2 density n~10^5-6 cm^-3, although important degeneracies prevent determining the exact conditions. The three GEMS are consistent with extrapolations of dense-gas star-formation laws derived in the nearby Universe, adding further evidence that the extreme star-formation rates observed in the most active galaxies at z~3 are a consequence of their important dense-gas contents. The dense-gas-mass fractions traced by HCN/[CI] and HCO+/[CI] line ratios are elevated, but not exceptional compared to other lensed dusty star-forming galaxies at z>2 and fall near the upper envelope of local ULIRGs. Our results also favor constant dense-gas depletion times in these populations.
