The inhomogeneous ISM toward PKS1830-211 SW - A detailed view on molecular gas at a look-back time of 7.5 Gyr

Abstract

Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the south-western source of the gravitational lens system PKS 1830-211, which is by far the best known target to study molecular gas in absorption at intermediate redshift. Determining line parameters and optical depths and performing Large Velocity Gradient radiative transfer calculations, the aims of this study are (1) to evaluate physical parameters of the absorbing foreground gas at z~0.89, in particular its homogeneity, and (2) to monitor the spectroscopic time variability caused by fluctuations of the z~2.5 background continuum source. We find, that the gas is quite inhomogeneous with n(H2)~2 x 10^3 cm^-3 for most molecular species but with higher values for H2CO and lower ones for SO. Measuring the CS J=1-0 transition during a time interval of more than a decade, from 2001 to 2012, the peak absorption depth of the line remains approximately constant, while the line shape undergoes notable variations. Covering the time between 1996 and 2013, CS, HCO+, and CH3OH data indicate maximal integrated optical depths in ~2001 and 2011/2012. This is compatible with a ~10 yr periodicity, which, however, needs confirmation by substantially longer time monitoring. Comparing molecular abundances with those of different types of Galactic and nearby extragalactic clouds we find that the observed cloud complex does not correspond to one particular type but to a variety of cloud types with more diffuse and denser components as can be expected for an observed region with a transverse linear scale of several parsec and a likely larger depth along the line-of-sight. A tentative detection of Galactic absorption in the c-C3H2 1(10)-1(01) line at 18.343 GHz is also reported.

arXiv commentAccepted for publication in A&A, 11 pages, 10 figures, 4 tables

References in corpus (34)

• Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S
• Molecules at z=0.89: A 4-mm-rest-frame absorption line survey toward PKS 1830-211
• Strong Limit on a Variable Proton-to-Electron Mass Ratio from Molecules in the Distant Universe
• The Identification of EGRET Sources with Flat-Spectrum Radio Sources
• The Time Delay in the Gravitational Lens PKS 1830-211
• A precise and accurate determination of the cosmic microwave background temperature at z=0.89
• Constraints on changes in fundamental constants from a cosmologically distant OH absorber/emitter
• Robust Constraint on a Drifting Proton-to-Electron Mass Ratio at z=0.89 from Methanol Observation at Three Radio Telescopes
• The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9
• The complex molecular absorption line system at z=0.886 towards PKS1830-211
• The redshift of the gravitationally lensed radio source PKS1830-211
• Interstellar HOCN in the Galactic center region
• Probing isotopic ratios at z = 0.89: molecular line absorption in front of the quasar PKS 1830-211
• An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles
• CS, HC3N and CH3CCH multi-line analyses towards starburst galaxies. The evolution of cloud structures in the central regions of galaxies
• PMN J0134-0931: A gravitationally lensed quasar with an unusual radio morphology
• Drastic changes in the molecular absorption at redshift z=0.89 toward the quasar PKS 1830-211
• The kinetic temperature of a molecular cloud at redshift 0.9: Ammonia in the gravitational lens PKS1830-211
• Formaldehyde Densitometry of Starburst Galaxies: Density-Independent Global Star Formation
• Probing the jet base of the blazar PKS1830-211 from the chromatic variability of its lensed images. Serendipitous ALMA observations of a strong gamma-ray flare
• Cosmic alignment towards the radio Einstein ring PKS 1830-211 ?
• Detection of chloronium and measurement of the 35Cl/37Cl isotopic ratio at z=0.89 toward PKS1830-211
• Changes in the measured image separation of the gravitational lens system, PKS 1830-211
• The line-of-sight distribution of water in the SgrB2 complex
• Helical Jet in the Gravitationally Lensed Blazar PKS1830-211
• Submillimeter water and ammonia absorption by the peculiar z~0.89 interstellar medium in the gravitational lens of the PKS 1830-211 system
• Redshifted molecular absorption systems towards PKS1830-211 and B0218+357: submillimeter CO, CI and H2O data
• The broad-band X-ray spectrum of the blazar PKS B1830-211 by Chandra and INTEGRAL
• Probing The Dust-To-Gas Ratio of z > 0 Galaxies Through Gravitational Lenses
• Reversal of infall in SgrB2(M) revealed by Herschel/HIFI observations of HCN lines at THz frequencies
• Interstellar Silicate Dust in the z=0.89 Absorber Towards PKS 1830-211: Crystalline Silicates at High Redshift?
• Formaldehyde Anti-Inversion at z=0.68 in the Gravitational Lens B0218+357
• Formaldehyde Silhouettes Against the Cosmic Microwave Background: A Mass-Limited, Distance-Independent, Extinction-Free Tracer of Star Formation Across the Epoch of Galaxy Evolution
• On Measuring the CMB Temperature at Redshift 0.89

Cited by in corpus (15)

• Illuminating the past 8 billion years of cold gas towards two gravitationally lensed quasars
• OH+ and H2O+ absorption toward PKS1830-211
• Blind HI and OH absorption line search: first results with MALS and uGMRT processed using ARTIP
• Detection of CH+, SH+, and their 13C- and 34S- isotopologues toward PKS1830-211
• Detection of extragalactic CF+ toward PKS1830-211 -- Chemical differentiation in the absorbing gas
• A study of submillimeter methanol absorption toward PKS1830-211: Excitation, invariance of the proton-electron mass ratio, and systematics
• Detection of deuterated molecules, but not of lithium hydride, in the z=0.89 absorber toward PKS1830-211
• Cosmo-tomography toward PKS1830-211: Variability of the quasar and of its foreground molecular absorption monitored with ALMA
• The ortho-to-para ratio of H${}_2$Cl${}^{+}$: Quasi-classical trajectory calculations and new simulations in light of new observations
• Methanol absorption in PKS B1830-211 at milliarcsecond scales
• Discovery of Hydrogen Radio Recombination Lines at z=0.89 towards PKS 1830-211
• Emergence of a new HI 21-cm absorption component at z~1.1726 towards the gamma-ray blazar PKS~2355-106
• A sub-ppm upper limit on the cosmological variations of the fine structure constant alpha
• New constraints on the values of the fundamental constants at a look-back time of 7.3 Gyr
• The 107 GHz methanol transition is a dasar in G0.253+0.016