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TOPIC: Arp 270

Blobrana

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Posts: 131433

Date: Mar 19 11:00 2015

NGC 3395 and NGC 3396	Permalink

Title: Outer regions of the merging system Arp 270 Author: A. Zasov, A. Saburova, I. Katkov, O. Egorov, V. Afanasiev Arp 270 (NGC 3395 and NGC 3396) is the system of two actively star-forming late-type galaxies in contact, which already have experienced at least one close encounter in the past. We performed long-slit observations of peripheric regions of this merging system with the 6-m telescope of SAO RAS. Line-of-sight velocity distribution along the slits was obtained for gas and stellar population. We found that the stellar component of NGC 3395 differs by its velocity from the emission gas component in the extended region in the periphery, which evidences a spatial separation of stars and gas in the tidally disturbed galaxy. Gas abundances obtained by different methods demonstrate that both galaxies are mildly underabundant (log(O/H) ~8.4) without significant variations of metallicity along the slits. By comparing stellar and gaseous masses of galaxies we came to conclusion that the chemical evolution of gas is badly described by the closed box model. It allows us to admit that the significant part of interstellar gas was swept out of galaxies during the preceding encounter(s). A special attention was paid to the extended kpc-size island of star formation between the galaxies. We have not found neither noticeable kinematic decoupling of this region from the adjacent areas, nor any peculiarities of its emission spectra, which evidences that it was formed recently from the gas of NGC 3395 in the transition region between the colliding galaxies. Read more (1851kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Mar 24 09:17 2013

Arp 270	Permalink

Title: Kinematics of Arp 270: gas flows, nuclear activity, and two regimes of star formation Authors: J. Zaragoza-Cardiel (Instituto de Astrofísica de Canarias), J. Font-Serra (Instituto de Astrofísica de Canarias), J. E. Beckman (Instituto de Astrofísica de Canarias), J. Blasco-Herrera (Instituto de Astrofísica de Andalucía), B. García-Lorenzo (Instituto de Astrofísica de Canarias), A. Camps (Instituto de Astrofísica de Canarias), O. Gonzalez-Martin (Instituto de Astrofísica de Canarias), C. Ramos Almeida (Instituto de Astrofísica de Canarias), N. Loiseau (XMM-Newton Science Operations Centre), L. Gutiérrez (Universidad Autónoma de México) We have observed the Arp 270 system (NGC 3395 & NGC 3396) in H{\alpha} emission using the GH{\alpha}FaS Fabry-Perot spectrometer on the 4.2m William Herschel Telescope (La Palma). In NGC 3396, which is edge-on to us, we detect gas inflow towards the centre, and also axially confined opposed outflows, characteristic of galactic superwinds, and we go on to examine the possibility that there is a shrouded AGN in the nucleus. The combination of surface brightness, velocity and velocity dispersion information enabled us to measure the radii, FWHM, and the masses of 108 HII regions in both galaxies. We find two distinct modes of physical behaviour, for high and lower luminosity regions. We note that the most luminous regions show especially high values for their velocity dispersions and hypothesise that these occur because the higher luminosity regions form from higher mass, gravitationally bound clouds while those at lower luminosity HII regions form within molecular clouds of lower mass, which are pressure confined. Read more (5294kb, PDF) __________________

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