Molecules atz= 0.89

Abstract

We present the results of a 7 mm spectral survey of molecular absorption lines originating in the disk of a z = 0.89 spiral galaxy located in front of the quasar PKS 1830−211. Our survey was performed with the Australia Telescope Compact Array and covers the frequency interval 30-50 GHz, corresponding to the rest-frame frequency interval 57-94 GHz. A total of 28 different species, plus 8 isotopic variants, were detected toward the south-west absorption region, located about 2 kpc from the center of the z = 0.89 galaxy, which therefore has the largest number of detected molecular species of any extragalactic object so far. The results of our rotation diagram analysis show that the rotation temperatures are close to the cosmic microwave background temperature of 5.14 K that we expect to measure at z = 0.89, whereas the kinetic temperature is one order of magnitude higher, indicating that the gas is subthermally excited. The molecular fractional abundances are found to be in-between those in typical Galactic diffuse and translucent clouds, and clearly deviate from those observed in the dark cloud TMC 1 or in the Galactic center giant molecular cloud Sgr B2. The isotopic ratios of carbon, nitrogen, oxygen, and silicon deviate significantly from the solar values, which can be linked to the young age of the z = 0.89 galaxy and a release of nucleosynthesis products dominated by massive stars. Toward the north-east absorption region, where the extinction and column density of gas is roughly one order of magnitude lower than toward the SW absorption region, only a handful of molecules are detected. Their relative abundances are comparable to those in Galactic diffuse clouds. We also report the discovery of several new absorption components, with velocities spanning between −300 and +170 km s −1 . Finally, the line centroids of several species (e.g., CH 3 OH, NH 3 ) are found to be significantly offset from the average velocity. If caused by a variation in the proton-to-electron mass ratio μ with redshift, these offsets yield an upper limit | Δμ μ | < 4×10 −6 , which takes into account the kinematical noise produced by the velocity dispersion measured from a large number of molecular species.

Detection of extragalactic argonium, ArH+, toward PKS 1830−211

“…However, the ArH + line profile shows a slight deviation from a simple Gaussian, and fit results and values of integrated opacity over velocity channels from −80 to +110 km s −1 are given in a separate column in Table 1. The weak velocity component at +170 km s −1 , previously only detected in the lines of HCO + , HCN, and H 2 O and all three strongly saturated near v = 0 km s −1 (Muller et al 2011(Muller et al , 2014b, is − surprisingly − also detected in the 36 ArH + spectrum. In contrast to the SW line of sight, where the absorption mostly resides in one bulky absorption feature (with the exception of the additional +170 km s −1 component), the ArH + absorption profile toward the NE image shows a remarkable series of narrow (a few km s −1 ) features spanning over ∼200 km s −1 , also seen, e.g., in the absorption profile of H 2 O (Muller et al 2014b).…”

The Mrk 231 molecular outflow as seen in OH

“…Prantzos et al 1996). Interestingly, a very low (but not so extreme) 16 O/ 18 O ∼ 50 ratio, together with a high 18 O/ 17 O ∼ 12 ratio, are also inferred in the arm of a spiral galaxy at z = 0.89 (Muller et al 2006(Muller et al , 2011. In Mrk 231, 18 OH is detected up to a velocity shift of ∼−600 km s −1 , although 18 OH enhancement at higher velocities is not ruled out.…”

Multimolecule ALMA observations toward the Seyfert 1 galaxy NGC 1097

“…Most of the deep and/or unbiased chemical studies in galaxies have been carried out at very low resolution (i.e., 100 pc, Wang et al 2004;Martín et al 2006Martín et al , 2011Aladro et al 2011aAladro et al , 2013Davis et al 2013;Watanabe et al 2014) but for absorption studies toward bright continuum high-z sources where, though extremely prolific in molecular detection, no spatial information can be obtained (Muller et al 2011(Muller et al , 2014. High resolution studies toward extragalactic sources have mostly focused toward the brightest nearby galaxies, as well as on the brightest species after carbon monoxide: HCN and HCO + (NGC 253 at 3 resolution, Knudsen et al (2007); M51 at 4 , Schinnerer et al 2010; NGC 1068 at 1 , Krips et al 2011; NGC 1097 at 3 , Hsieh et al 2012; or a sample of luminous infrarred galaxies (LIRGs) at 2 −10 , Imanishi et al 2007Imanishi et al , 2009).…”