arXiv subjects

A. A. Smirnova

Publications and source records attributed to A. A. Smirnova.

16 recordsLinked to original sources

arXiv2026

Archaeology of Galactic Nuclei Activity

Considerable observational evidence suggests that the activity of supermassive black holes in galactic nuclei is transient. The term ``active galactic nuclei archaeology'' has even been coined. This implies the possibility of reconstructing the history of activity, such as changes in the nuclear luminosity over time across various regions of the electromagnetic spectrum, by analysing how this activity manifested itself on galactic and extragalactic spatial scales. These phenomena include relic radio structures, gas clouds illuminated by the ``ionising echo'' of past activity, and Fermi/eROSITA bubbles. We provide a review of the results of galactic nucleus activity studies, focusing on its observable impact on the intergalactic medium and circumgalactic environment. Our main focus is on optical observations of ionisation cones and evidence of switching between radiative (ionisation cones) and kinetic (radio jets) modes of nuclear activity.

astro-ph.GA↗

arXiv2021

The TELPERION Survey for Distant [O III] Clouds around Luminous and Hibernating AGN

We present a narrowband [O III] imaging survey of 111 AGN hosts and 17 merging-galaxy systems, in search of distant extended emission-line regions (EELRs) around AGN (either extant or faded). Our data reach deeper than detection from the broadband SDSS data, and cover a wider field than some early emission-line surveys used to study extended structure around AGN. Spectroscopic followup confirms two new distant AGN-ionized clouds, in the merging systems NGC 235 and NGC 5514, projected at 26 and 75 kpc from the nuclei (respectively). We also recover the previously-known region in NGC 7252. These results strengthen the connection between EELRs and tidal features; kinematically quiescent distant EELRs are virtually always photoionized tidal debris. We see them in ~10% of the galaxies in our sample with tidal tails. Energy budgets suggest that the AGN in NGC 5514 has faded by >3 times during the extra light-travel time ~250,000 years from the nucleus to the cloud and then to the observer; strong shock emission in outflows masks the optical signature of the AGN. For NGC 235 our data are consistent with but do not unequivocally require variation over ~85,000 years. In addition to these very distant ionized clouds, luminous and extensive line emission within four galaxies - IC 1481, ESO 362-G08, NGC 5514, and NGC 7679. IC 1481 shows apparent ionization cones, a rare combination with its LINER AGN spectrum. In NGC 5514, we measure a 7-kpc shell expanding at ~370 km/s west of the nucleus.

astro-ph.GA↗

arXiv2020

Internal Kinematics of the Seyfert Galaxy Mkn 938

We present the results of a detailed study of the central part of the Seyfert galaxy Mkn 938. Observational data were obtained with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences using integral-field spectrograph MPFS and a scanning Fabry--Perot interferometer. Mkn 938 is interesting for being a result of a merger of two gas-rich galaxies, and we observe the final stage of this interaction accompanied with an extremely powerful burst of star formation and nuclear activity. Our analysis of the kinematics of gas and stars revealed the presence of gas outflow in the circumnuclear region Mkn 938 with velocities ranging from -370 to -480 km/s, and allowed us for the first time to map the high-velocity galactic wind in NaD absorption line on large spatial scale in this galaxy.

astro-ph.GA↗

arXiv2019

Extended ionized-gas structures in Seyfert 2 galaxy Mrk 78

Search for and study of extended emission-line regions (EELRs) related to AGN in early-type galaxies is interesting to probe the history of nuclear ionization activity and also to understand the process of external gas accretion. In this work, we present observations of the EELR in Mrk 78 obtained at the 6-m Russian telescope using the long-slit and 3D spectroscopy methods. We show that ionized-gas clouds at the 12-16 kpc projected distances from the nucleus are ionized by the AGN radiation. Also we have checked if the galaxy appearing in the optical images in the immediate neighbourhood of Mrk 78 near the external clouds is a dwarf companion or a part of a tidal structure. However, the spectrum of this galaxy, SDSS J074240.37+651021.4, obtained at the 6-m telescope corresponds to the distant background galaxy.

astro-ph.GA↗

arXiv2018

A close look at the well-known Seyfert galaxy: extended emission filaments in Mrk6

Using various techniques of optical observations at the 6-m Russian telescope (emission-line images, long-slit and 3D spectroscopy), we have studied large-scale morphology and kinematics of the ionized gas in the Seyfert galaxy Mrk6. Having a significantly deeper images and spectra than those in previous works, we have not only mapped the ionized gas in the stellar disc but also found a system of faint filaments elongated in the NE direction up to a projected distance of 40 kpc (4.3R$_{25}$). Kinematics as well as an ionization state of the filament gas suggest the scenario that hard radiation of the active nucleus illuminated the matter accreted from outside and orbiting almost orthogonally to the Mrk 6 stellar disc. A possible source of gas accretion is still unknown, a deep image taken with the 1-m Byrakan Schmidt telescope does not show any stellar counterparts at the level of 27-28 mag/arcsec$^2$.

astro-ph.GA↗

arXiv2014

Panoramic Spectroscopy of Galaxies with Star-formation Regions. A Study of SBS 1202+583

The methods of panoramic (3D) spectroscopy are used in a detailed study of galaxies with ongoing star formation chosen from among objects in seven selected fields of the Second Byurakan Survey (SBS). This article deals with the irregular galaxy SBS 1202+583, which our classification scheme identifies as being in a continuous phase of starformation. Observations were made with the panoramic spectrographs MPFS at the 6-m telescope of the Special Astrophysical Observatory (SAO) of the Russian Academy of Sciences and VAGR at the 2.6-m telescope of the Byurakan Astrophysical Observatory (BAO) in Armenia. The data are used to construct charts of the radiative fluxes in the continuum and various emission lines. Special attention is devoted to analyzing the emission in the Hα hydrogen recombination line and in the forbidden low-ionization doublets of nitrogen [NII]λλ6548, 6583 and sulfur [SII]λλ 6716,6731, and the ratios of the intensities of the forbidden lines to Hα. The observable characteristics (sizes, Hα fluxes, etc.) of nine HII regions are studied. The estimated current rates of starformation in the individual HII regions based on the Hα fluxes lie within the range of 0.3-1.2 Msun/year. The dependence of the ratio of the intensities of the emission in these two forbidden doublets on the rate of star formation in the HII regions is found.

astro-ph.GA↗

arXiv2011

The origin of gas in the Extended Narrow Line Region of nearby Seyfert galaxies.I. NGC 7212

The Extended Narrow Line Region (ENLR) of Active Galactic Nuclei (AGN) is a region of highly ionized gas with a size of few up to 15-20 kpc. When it shows a conical or bi-conical shape with the apexes pointing towards the active nucleus, this region is also called ionization cones. The ionization cones are an evidence of the Unified Model that predicts an anisotropic escape of ionizing photons from the nucleus confined to a cone by a dusty torus. Many details about the complex structure of the ENLR still remain unveiled, as for example the origin of the ionized gas. Here we present new results of a study of the physical and kinematical properties of the circumnuclear gas in the nearby Seyfert 2 galaxy NGC 7212. Medium and high resolution integral field spectra and broad-band photometric data were collected and analysed in the frame of an observational campaign of nearby Seyfert galaxies, aiming to handle the complicated issue of the origin of the gas in the ENLR. This work is based on: (i) analysis of gas physical properties (density, temperature and metallicity), (ii) analysis of emission line ratios, and (iii) study of kinematics of gas and stars. By reconstructing the [O III]/Hbeta ionization map, we pointed out for the first time the presence of an ionization cone extended up to about 6 kpc, made by a large amount of low metallicity gas, kinematically disturbed and decoupled from stars, whose highly ionized component shows radial motions at multiple velocities proved by the complex profiles of the specral lines. Since NGC 7212 is a strongly interacting triple galaxy system, the gravitational effects are likely to be at the origin of the ENLR in this Seyfert galaxy.

astro-ph.CO↗

arXiv2011

Gas motions mapping for three Seyfert galaxies

We report preliminary results of a kinematical study for three Seyfert galaxies selected from a sample of nearby active galactic nuclei observed using 3D spectroscopy. The observations were performed at the prime focus of the SAO RAS 6-m telescope with the integral-field spectrograph MPFS and with a scanning Fabry-Perot interferometer, installed on the multimode device SCORPIO. Based on these data, the monochromatic maps and velocity fields in different emission lines were constructed. We have detected a nuclear outflow or ionized gas motions associated with a radio jet in all galaxies circumnuclear regions.

astro-ph.CO↗

arXiv2010

Seyfert galaxies that are undergoing merging but appear non-interacting

We present new broad-band optical images of some merging Seyfert galaxies that were earlier considered to be non-interacting objects. On our deep images obtained at the Russian 6-m telescope we have detected elongated tidal envelopes belonging to satellites debris with a surface R-band brightness about 25-26.5 mag/arcsec^2. These structures are invisible in Sloan Digital Sky Survey (SDSS) pictures because of their photometric limit. We found that 35 per cent of the sample of isolated galaxies has undergone merging during the last 0.5-1 Gyr. Our results suggest that statistic studies based on popular imaging surveys (SDSS or Second Palomar Observatory Sky Survey (POSS-II)) can lead to underestimation of the fraction of minor mergers among galaxies with active nuclei (AGN). This fact impacts on statistics and must be taken into consideration when finding connection between minor/major merging or interactions and nucleus activity.

astro-ph.CO↗

arXiv2009

3D spectroscopy of merger Seyfert galaxy Mrk 334: nuclear starburst, superwind and the circumnuclear cavern

We are presenting new results on kinematics and structure of the Mrk 334 Seyfert galaxy. Panoramic (3D) spectroscopy is performed at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences using the MPFS integral-field spectrograph and scanning Fabry--Perot interferometer. The deep images have revealed that Mrk 334 is observed during the final stage of its merging with a massive companion. A possible mass ratio ranges from 1/5 to 1/3. The merger has triggered mass redistribution in the disk resulting in an intensification of nuclear activity and in a burst of star formation in the inner region of the galaxy. The circumnuclear starburst is so intense that its contribution to the gas ionization exceeds that contribution of the AGN. We interpret the nuclear gas outflow with velocities of ~200 km/s as a galactic superwind that accompanies the violent star formation. This suggestion is consistent with the asymmetric X-ray brightness distribution in Mrk 334. The trajectory of the fragments of the disrupted satellite in the vicinity of the main galaxy nucleus can be traced. In the galaxy disk a cavern is found that is filled with a low-density ionized gas. We consider this region to be the place where the remnants of the companion have recently penetrated through the gaseous disk of the main galaxy.

astro-ph.CO↗

arXiv2008

3D Spectroscopic Study of the Line Emitting Regions of Mrk 493

We report the results of 3D spectroscopic observations of Mrk 493 (NLS1 galaxy) with the integral-field spectrograph MPFS of the SAO RAS 6-m telescope. The difference in the slope of the optical continuum emission intensity across the nucleus part and an extensive continuum emission region} is detected. The emission in lines (H$α$, H$β$, [OIII], etc.) coincides with a composite nuclear region: an AGN plus a circum-nuclear star-forming ring observed in the HST UV/optical images. The [SII] emission region tends to be up to 1kpc around the center. The H$α$ and H$β$ could be decomposed into three components (broad $\sim$ 2000 km/s. intermediate $\sim$ 700 km/s and narrow $\sim$ 250 km/s). We found that width ($\sim$ 750 km/s) of the Fe II lines correspond to the intermediate component, that may indicate a non-BLR origin of the Fe II lines, or that a large fraction of the Fe II emission arise in the outher parts of the BLR. The weak broad component detected in the H$α$, H$β$ and He$λ$4686 may come from the unresolved central BLR, but also partly produced by violent starburst in the circum-nuclear ring. Moreover, diagnostic diagrams clearly show presence of the HII regions (not a Sy 1 nucleus) in the NLR of Mrk 493.

astro-ph↗

arXiv2008

Merging as a key to reforming of disk and AGN triggering in Sy galaxy Mrk334

We have studied the kinematics of the ionized gas and stellar component in Mrk334 using methods of panoramic (3D) spectroscopy. The observations were performed at the prime focus of the SAO RAS 6-m telescope with the integral-field spectrograph MPFS (Afanasiev et al. 2001) and with a scanning Fabry-Perot interferometer (FPI), installed on the multimode device SCORPIO (Afanasiev & Moiseev 2005). Based on these data, the monochromatic maps and velocity fields in different emission lines of the ionized gas were constructed. The diagnostic diagrams have been made based on the emission lines ratios.

astro-ph↗

arXiv2007

The gas kinematics in Mrk 533 nucleus and circumnuclear region: a gaseous outflow

We present an analysis of 3D spectra of Mrk 533, observed with the integral-field spectrograph MPFS and using the Fabry Perot Interferometer (FPI) of the SAO RAS 6-m telescope. We found emissions of gas from the active Sy 2 nucleus in the centre and also from the HII regions in a spiral structure and a circumnuclear region. The gas kinematics shows regular non-circular motions in the wide range of galactocentric distances from 500 pc up to 15 kpc. The maps of inward and outward radial motions of the ionized gas was constructed. We found that the narrow line region (NLR) is composed of at least two (probably three) kinematically separated regions. We detect a stratification in the NLR of Mrk 533 with the outflow velocity ranging from 20-50 km/s to 600-700 km/s, respectively, on the radial distances of ~2.5 and ~1.5 kpc. The maximal outflow velocity comes from the nucleus and corresponds to the position of the observed radio structure, which is assumed to be created in an approaching jet. We suggest that these ionized gas outflows are triggered by the radio jet intrusion in an ambient medium.

astro-ph↗

arXiv2006

Observational evidence for AGN fueling. I. The merging of NGC6104 with a companion

We investigate in details the kinematics and morphology of the Seyfert galaxy NGC6104 in order to identify the mechanism of gas transportation to the active galactic nucleus (AGN). Our observational data were obtained at the 6-m Special Astrophysical Observatory telescope with the MPFS integral-field spectrograph and the SCORPIO universal device in three modes: direct imaging, a scanning Fabry-Perot interferometer, and long-slit spectroscopy. Images from the HST archive were invoked to study the structure of the circumnuclear region. An analysis of deep images has revealed that NGC6104 is in the phase of active merging with a companion galaxy. We have been able to study the detailed picture of ionized gas motions up to galactocentric distances of 14 kpc and to construct the stellar velocity field for the inner region. The radial gas motions toward the AGN along the central bar play a significant role at galactocentric distances of 1-5 kpc. In addition, we have detected an outflow of ionized gas from the nucleus that presumably resulted from the intrusion of a radio jet into the ambient interstellar medium. Using diagnostic diagrams, we estimate the contributions from the AGN and star formation to the galactic gas ionization. We estimate the bar pattern speed by the Tremaine-Weinberg method and show that the inner ring observed in the galactic images has a resonant nature. Two possible ring formation scenarios (before and during the interaction with a companion) are discussed.

astro-ph↗

arXiv2005

The Gas Content in Galactic Disks: Correlation with Kinematics

We consider the relationship between the total HI mass in late-type galaxies and the kinematic properties of their disks. The mass $M_HI$ for galaxies with a wide variety of properties, from dwarf dIrr galaxies with active star formation to giant low-brightness galaxies, is shown to correlate with the product $V_c R_0$ ($V_c$ is the rotational velocity, and $R_0$ is the radial photometric disks scale length), which characterizes the specific angular momentum of the disk. This relationship, along with the anticorrelation between the relative mass of HI in a galaxy and $V_c$, can be explained in terms of the previously made assumption that the gas density in the disks of most galaxies is maintained at a level close to the threshold (marginal) stability of a gaseous layer to local gravitational perturbations. In this case, the regulation mechanism of the star formation rate associated with the growth of local gravitational instability in the gaseous layer must play a crucial role in the evolution of the gas content in the galactic disk.

astro-ph↗

arXiv2005

New photometric and spectroscopic observations of the Seyfert galaxy Mrk 315

We present new important results about the intermediate-type Seyfert galaxy Mrk 315, recently observed through optical imaging and integral-field spectroscopy. Broad-band images were used to study the morphology of the host galaxy, narrow-band H-alpha images to trace the star forming regions, and middle-band [O III] images to evidence the distribution of the highly ionised gas. Some extended emission regions were isolated and their physical properties studied by means of flux calibrated spectra. High resolution spectroscopy was used to separate different kinematic components in the velocity fields of gas and stars. Some peculiar features characterise this apparently undisturbed and moderately isolated active galaxy. Such features, already investigated by other authors, are re-analysed and discussed in the light of these new observations. The most relevant results we obtained are: the multi-tiers structure of the disc; the presence of a quasi-ring of regions with star formation much higher than previous claims; a secondary nucleus confirmed by a stellar component kinematically decoupled by the main galaxy; a new hypothesis about the controversial nature of the long filament, initially described as hook-shaped, and more likely made of two independent filaments caused by interaction events between the main galaxy and two dwarf companions.

astro-ph↗