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Sub-arcsecond imaging of the water emission in Arp 220.

ABSTRACT: Aims:Extragalactic observations of water emission can provide valuable insights into the excitation of the interstellar medium. In particular they allow us to investigate the excitation mechanisms in obscured nuclei, i.e. whether an active galactic nucleus or a starburst dominate. Methods:We use sub-arcsecond resolution observations to tackle the nature of the water emission in Arp 220. ALMA Band 5 science verification observations of the 183 GHz H2O 313-220 line, in conjunction with new ALMA Band 7 H2O 515-422 data at 325 GHz, and supplementary 22 GHz H2O 616 - 523 VLA observations, are used to better constrain the parameter space in the excitation modelling of the water lines. Results:We detect 183 GHz H2O and 325 GHz water emission towards the two compact nuclei at the center of Arp 220, being brighter in Arp 220 West. The emission at these two frequencies is compared to previous single-dish data and does not show evidence of variability. The 183 and 325 GHz lines show similar spectra and kinematics, but the 22 GHz profile is significantly different in both nuclei due to a blend with an NH3 absorption line. Conclusions:Our findings suggest that the most likely scenario to cause the observed water emission in Arp 220 is a large number of independent masers originating from numerous star-forming regions.

SUBMITTER: Konig S

PROVIDER: S-EPMC5687566 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Sub-arcsecond imaging of the water emission in Arp 220.

König S S Martín S S Muller S S Cernicharo J J Sakamoto K K Zschaechner L K LK Humphreys E M L EML Mroczkowski T T Krips M M Galametz M M Aalto S S Vlemmings W H T WHT Ott J J Meier D S DS Fuente A A García-Burillo S S Neri R R

Astronomy and astrophysics 20170602

<h4>Aims</h4>Extragalactic observations of water emission can provide valuable insights into the excitation of the interstellar medium. In particular they allow us to investigate the excitation mechanisms in obscured nuclei, i.e. whether an active galactic nucleus or a starburst dominate.<h4>Methods</h4>We use sub-arcsecond resolution observations to tackle the nature of the water emission in Arp 220. ALMA Band 5 science verification observations of the 183 GHz H<sub>2</sub>O 3<sub>13</sub>-2<su ...[more]

PMID: 29151605

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Project description:Concentration- and time-dependent genomic changes in the mouse urinary bladder following exposure to arsenate in drinking water for up to twelve weeks. Inorganic arsenic (Asi) is a known human bladder carcinogen. The objective of this study was to examine the concentration dependence of the genomic response to Asi in the urinary bladders of mice. C57BL/6J mice were exposed for 1 or 12 weeks to arsenate in drinking water at concentrations of 0.5, 2, 10, and 50 mg As/L. Urinary bladders were analyzed using gene expression microarrays. A consistent reversal was observed in the direction of gene expression change: from predominantly decreased expression at 1 week to predominantly increased expression at 12 weeks. These results are consistent with evidence from in vitro studies of an acute adaptive response that is suppressed on longer exposure due to down-regulation of Fos. Pathways with the highest enrichment in gene expression changes were associated with epithelial-to-mesenchymal transition, inflammation, and proliferation. Benchmark dose (BMD) analysis determined that the lowest median BMD values for pathways were above 5 mg As/L, despite the fact that pathway enrichment was observed at the 0.5 mg As/L exposure concentration. This disparity may result from the non-monotonic nature of the concentration-responses for the expression changes of a number of genes, as evidenced by the much fewer gene expression changes at 2 mg As/L compared to lower or higher concentrations. Pathway categories with concentration-related gene expression changes included cellular morphogenesis, inflammation, apoptosis/survival, cell cycle control, and DNA damage response. The results of this study provide evidence of a concentration-dependent transition in the mode of action for the subchronic effects of Asi in mouse bladder cells in the vicinity of 2 mg Asi/L. Female C57Bl/J mice will be exposed to COLD Arsenate in drinking water. One week interium sac on 7/18/06. 100 samples including liver, lung, kidney and bladder. Bladder will be analyzed with microarrays, 24 samples. Twelve week terminal sac on 10/05/06. 75 total samples including lung, kidney, and bladder. Bladdler will be analyzed by microarray, 25 samples. Drinking water containing As will be prepared weekly with monitoring to determine amount used by mice. Following tissues will be available for genomic study: Bladder, liver, lung, and kidney.

Dataset Information

Sub-arcsecond imaging of the water emission in Arp 220.

Publications

Sub-arcsecond imaging of the water emission in Arp 220.

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