Herschel spectroscopic observations of the compact obscured nucleus in Zw 049.057

摘要: Context. The LIRG Zw 049.057 contains a compact obscured nucleus where considerable amount of the galaxy's luminosity is generated. This dusty environment that rich in molecular gas. One approach to probing this kind and revealing what hidden behind dust study rotational lines molecules couple well with IR radiation emitted by dust. Methods. We observed PACS SPIRE onboard Herschel Space Observatory H2O, H218O, OH, 18OH, [O I]. modeled unresolved core galaxy using spherically symmetric radiative transfer code. Results. present full FTS spectrum 049.057, along relevant spectral scans range. find minimum two different components (nuclear extended) are required order account for line spectrum. nuclear component has radius 10-30 pc, very high infrared surface brightness (1e14 Lsun/kpc2), warm (Td > 100 K), large H2 column density (NH2 = 1e24-1e25 cm-2). modeling also indicates H2O (5e-6) OH (4e-6) abundances relative as low 16O/18O-ratio 50-100. prominent infall signature I] line. tentatively detect 500 km/s outflow 313->202 Conclusions. presence either buried active galactic or dense starburst.nThe abundance comparable other (ultra-)luminous galaxies such NGC 4418 Arp 220 - hot cores Milky Way. enhancement 18O possible indicator similar evolutionary stage nuclei more advanced than 4418.