arXiv subjects

Aleksandrina A. Smirnova

Publications and source records attributed to Aleksandrina A. Smirnova.

3 recordsLinked to original sources

arXiv2023

Ionizing spotlight of active galactic nucleus

Ionization cones and relativistic jets give us one of the most large-scale example of active galactic nuclei (AGN) influence on the surrounding gas environment in galaxies and beyond. The study of ionization cones makes it possible not only to test the predictions of the unified model of galactic activity, but also to probe galaxy gas environment and trace how the luminosity of the nucleus changes over time (a light echo). In the external galactic or even extragalactic gas ionization cones create Extended Emission-Line Regions (EELRs) which can span distances from several to hundreds kpc away a host galaxy. We review the recent results of studying the gas kinematics and its ionization properties in EELRs with a special attention to search of fading AGN radiation on the time scale $\mbox{few}\times(10^4-10^5)$ yr. The role of modern narrow-band and integral-field surveys in these researches is also considered.

astro-ph.GA↗

arXiv2023

Enigmatic emission structure around Mrk 783: cross-ionization of a companion in 100 kpc away

Mrk 783 is a narrow-line Seyfert 1 galaxy that possesses a relatively large two-sided radio emission extending up to 14 kpc from the active nucleus possibly connected with a large-scale ionized gas emission. We obtained a deep [OIII] image that revealed an extended system of emission knots and diffuse ionized gas surrounding the main galaxy. The high-excited gas is related not only with the radio structure, but also with tidal features illuminated by the active nucleus radiation up to the projected distance 41 kpc as it follows from the emission lines intensities and kinematics derived from the long-slit spectroscopic data. Moreover the part of the disk of the companion galaxy SDSS J130257.20+162537.1 located at 99 kpc projected distances to the north of Mrk 783 also falls in the AGN ionizing cone. It is possible that Mrk 783 can be considered as `Hanny's Voorwerp precursor', i.e. a galaxy that demonstrates signs of sequential switching from radio-loud to radio-quiet nuclear activity, in the moment before falling of its ionization luminosity.

astro-ph.GA↗

arXiv2010

Star Formation History in the Central Region of the Barred Galaxy NGC 7177

Using the method of integral-field (3D) spectroscopy, we have investigated the kinematics and distribution of the gas and stars at the center of the early-type spiral galaxy with a medium scale bar NGC 7177 as well as the change in the mean age of the stellar population along the radius. A classical picture of radial gas inflow to the galactic center along the shock fronts delineated by dust concentration at the leading edges of the bar has been revealed. The gas inflow is observed down to a radius R = 1".5 -- 2", where the gas flows at the inner Lindblad resonance concentrate in an azimuthally highly inhomogeneous nuclear star formation ring. The bar in NGC 7177 is shown to be thick in z coordinate; basically, it has already turned into a pseudo-bulge as a result of secular dynamical evolution. The mean stellar age inside the star formation ring, in the galactic nucleus, is old, ~10 Gyr. Outside, at a distance R = 6" - 8" from the nucleus, the mean age of the stellar population is ~2 Gyr. If we agree that the bar in NGC 7177 is old, then, obviously, the star formation ring has migrated radially inward in the last 1-2 Gyr, in accordance with the predictions of some dynamical models.

astro-ph.CO↗