Stellar Nuclei and Inner Polar Disks in Lenticular Galaxies

Сильченко, О. К.

doi:10.3847/0004-6256/152/3/73

Cited by 7 publications

(3 citation statements)

References 70 publications

(97 reference statements)

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“…In the outer bright inhomogeneous ring starting from r > 12 ′′ the strong emission lines have been detected partially excited by star-forming process (along our slit -only to the west from the nucleus). In the center (r < 2 ′′ ) of PGC 48114 the mean age of the stellar population is about 5 Gyr, abundance ratio [Mg/Fe]≈ +0.1, and the metallicity [Z/H] = +0.3 -typical values for the nuclei of lenticular galaxies (Sil'chenko 2006(Sil'chenko , 2016. However, the low [Mg/Fe], within the range of 0 • • • + 0.1, kept all along the galaxy is quite untypical for the contemporary lenticular galaxies (Sil'chenko, Proshina, Shulga et al 2012); it implies an extended star formation epoch in the disk.…”

Section: Discussionmentioning

confidence: 99%

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗

Proshina

Kniazev

Сильченко

2019

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Rings in S0s are enigmatic features which can however betray the evolutionary paths of particular galaxies. We have undertaken long-slit spectroscopy of five lenticular galaxies with UV-bright outer rings. The observations have been made with the Southern African Large Telescope (SALT) to reveal the kinematics, chemistry, and the ages of the stellar populations and the gas characteristics in the rings and surrounding disks. Four of the five rings are also bright in the Hα emission line, and the spectra of the gaseous rings extracted around the maxima of the Hα equivalent width reveal excitation by young stars betraying current star formation in the rings. The integrated level of this star formation is 0.1-0.2 M ⊙ per year, with the outstanding value of 1 M ⊙ per year in NGC 7808. The difference of chemical composition between the ionized gas of the rings which demonstrate nearly solar metallicity and the underlying stellar disks which are metal poor implies recent accretion of the gas and star formation ignition; the star formation history estimated by using different star formation indicators implies that the star formation rate decreases with e-folding time of less than 1 Gyr. In NGC 809 where the UV-ring is well visible but the Hα emission line excited by massive stars is absent, the star formation has already ceased.

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Section: Discussionmentioning

confidence: 99%

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗

Proshina

Kniazev

Сильченко

2019

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“…van Gorkom et al 1987Whitmore et al 1990), circum-nuclear polar rings (e.g. Sil'chenko & Afanasiev 2004;Chilingarian et al 2009;Sil'chenko 2016), counter-rotations (e.g. Katkov et al 2013Katkov et al , 2014Ilyina et al 2014;Katkov et al 2015Katkov et al , 2016Pizzella et al 2018) and cylindrical rotation (e.g.…”

Section: Star-forming S0smentioning

confidence: 99%

Double-peak emission line galaxies in the SDSS catalogue

Maschmann

Melchior

Mamon

et al. 2020

A&A

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Double-peak narrow emission line galaxies have been studied extensively in the past years, in the hope of discovering late stages of mergers. It is difficult to disentangle this phenomenon from disc rotations and gas outflows with the sole spectroscopic measurement of the central 3″. We aim to properly detect such galaxies and distinguish the underlying mechanisms with a detailed analysis of the host-galaxy properties and their kinematics. Relying on the Reference Catalogue of Spectral Energy Distribution, we developed an automated selection procedure and found 5663 double-peak emission line galaxies at z < 0.34 corresponding to 0.8% of the parent database. To characterise these galaxies, we built a single-peak no-bias control sample (NBCS) with the same redshift and stellar mass distributions as the double-peak sample (DPS). These two samples are indeed very similar in terms of absolute magnitude, [OIII] luminosity, colour-colour diagrams, age and specific star formation rate, metallicity, and environment. We find an important excess of S0 galaxies in the DPS, not observed in the NBCS, which cannot be accounted for by the environment, as most of these galaxies are isolated or in poor groups. Similarly, we find a relative deficit of pure discs in the DPS late-type galaxies, which are preferentially of Sa type. In parallel, we observe a systematic central excess of star formation and extinction for double peak (DP) galaxies. Finally, there are noticeable differences in the kinematics: The gas velocity dispersion is correlated with the galaxy inclination in the NBCS, whereas this relation does not hold for the DPS. Furthermore, the DP galaxies show larger stellar velocity dispersions and they deviate from the Tully-Fisher relation for both late-type and S0 galaxies. These discrepancies can be reconciled if one considers the two peaks as two different components. Considering the morphological biases in favour of bulge-dominated galaxies and the star formation central enhancement, we suggest a scenario of multiple, sequential minor mergers driving the increase of the bulge size, leading to larger fractions of S0 galaxies and a deficit of pure disc galaxies.

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“…van Gorkom et al 1987Whitmore et al 1990), circum-nuclear polar rings (e.g. Sil'chenko & Afanasiev 2004Chilingarian et al 2009;Sil'chenko 2016), counter-rotations (e.g. Katkov et al 2013Katkov et al , 2014Ilyina et al 2014;Katkov et al 2015Katkov et al , 2016Pizzella et al 2018) and cylindrical rotation (e.g.…”

Section: Star-forming S0smentioning

confidence: 99%

Double-peak emission line galaxies in the SDSS catalogue. A minor merger sequence

Maschmann,

Melchior,

Mamon

et al. 2020

Preprint

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Double-peak narrow emission line galaxies have been studied extensively in the past years, in the hope of discovering late stages of mergers. It is difficult to disentangle this phenomenon from disc rotations and gas outflows with the sole spectroscopic measurement of the central 3 . We aim to properly detect such galaxies and distinguish the underlying mechanism with a detailed analysis of the host-galaxy properties and their kinematics. Relying on RCSED, we developed an automated selection procedure and found 5 663 double-peak emission line galaxies at z < 0.34 corresponding to 0.8% of the parent database. To characterise these galaxies, we built a single-peak no-bias control sample (NBCS) with the same redshift and stellar mass distributions as the double-peak sample (DPS). These two samples are indeed very similar in terms of absolute magnitude, [OIII] luminosity, colour-colour diagrams, age and specific star formation rate, metallicity, and environment. We find an important excess of S0 galaxies in the DPS, not observed in the NBCS, and which cannot be accounted for by the environment, as most of these galaxies are isolated or in poor groups. Similarly, we find a relative deficit of pure discs in the DPS late-type galaxies, that are preferentially of Sa type. In parallel, we observe a systematic central excess of star formation and extinction for DP galaxies. Finally, there are noticeable differences in the kinematics: the gas velocity dispersion is correlated with the galaxy inclination in the NBCS, whereas this relation does not hold for the DPS. Furthermore, the DP galaxies show larger stellar velocity dispersions and they deviate from the Tully-Fisher relation for both late-type and S0 galaxies. These discrepancies can be reconciled if one considers the two peaks as two different components. Considering the morphological biases in favour bulge dominated galaxies and the star-formation central enhancement, we suggest a scenario of multiple sequential minor mergers driving the increase of the bulge size, leading to larger fractions of S0 galaxies and a deficit of pure disc galaxies.

show abstract

Stellar Nuclei and Inner Polar Disks in Lenticular Galaxies

Cited by 7 publications

References 70 publications

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗

Double-peak emission line galaxies in the SDSS catalogue

Double-peak emission line galaxies in the SDSS catalogue. A minor merger sequence

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Stellar Nuclei and Inner Polar Disks in Lenticular Galaxies

Cited by 7 publications

References 70 publications

Star-forming Rings in Lenticular Galaxies: Origin of the Gas∗

Star-forming Rings in Lenticular Galaxies: Origin of the Gas∗

Double-peak emission line galaxies in the SDSS catalogue

Double-peak emission line galaxies in the SDSS catalogue. A minor merger sequence

Contact Info

Product

Resources

About

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗

Star-forming Rings in Lenticular Galaxies: Origin of the Gas^∗