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In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS) and GigaHertz Peaked Spectrum (GPS) and 14 Megahertz-Peaked spectrum (MPS) radio sources located at z ≤ 1. The radio luminosity (LR) of the sample varies between Log L R ∼ 23.2 and 27.7 W Hz−1. We obtained optical spectra for all sources from SDSS-DR12 and performed a stellar population synthesis using the starlight code. We derived stellar masses (M⋆), ages 〈 t ⋆〉, star formation rates (SFR), metallicities 〈 Z ⋆〉 and internal reddening A V for all young AGNs of our sample. A visual inspection of the SDSS images was made to assign a morphological class for each source. Our results indicate that the sample is dominated by intermediate to old stellar populations and there is no strong correlation between optical and radio properties of these sources. Also, we found that young AGNs can be hosted by elliptical, spiral and interacting galaxies, confirming recent findings. When comparing the optical properties of CSS/GPS and MPS sources, we do not find any significant difference. Finally, the Mid-Infrared WISE colours analysis suggests that the compact radio sources defined as powerful AGNs are, in general, gas-rich systems. [ABSTRACT FROM AUTHOR]

We report on our combined analysis of HST , VLT/MUSE, VLT/SINFONI, and ALMA observations of the local Seyfert 2 galaxy, NGC 5728 to investigate in detail the feeding and feedback of the active galactic nucleus (AGN). The data sets simultaneously probe the morphology, excitation, and kinematics of the stars, ionized gas, and molecular gas over a large range of spatial scales (10 pc to 10 kpc). NGC 5728 contains a large stellar bar that is driving gas along prominent dust lanes to the inner 1 kpc where the gas settles into a circumnuclear ring. The ring is strongly star forming and contains a substantial population of young stars as indicated by the lowered stellar velocity dispersion and gas excitation consistent with H  ii regions. We model the kinematics of the ring using the velocity field of the CO (2–1) emission and stars and find it is consistent with a rotating disc. The outer regions of the disc, where the dust lanes meet the ring, show signatures of inflow at a rate of 1 M |$\odot$|  yr−1. Inside the ring, we observe three molecular gas components corresponding to the circular rotation of the outer ring, a warped disc, and the nuclear stellar bar. The AGN is driving an ionized gas outflow that reaches a radius of 250 pc with a mass outflow rate of 0.08 M |$\odot$|  yr−1 consistent with its luminosity and scaling relations from previous studies. While we observe distinct holes in CO emission which could be signs of molecular gas removal, we find that largely the AGN is not disrupting the structure of the circumnuclear region. [ABSTRACT FROM AUTHOR]

We map optical and near-infrared (NIR) stellar population properties of the inner 320 × 535 pc2 of the elliptical galaxy NGC 1052. The optical and NIR spectra were obtained using the Gemini Integral Field Units of the GMOS instrument and NIFS, respectively. By performing stellar population synthesis in the optical alone, we find that this region of the galaxy is dominated by old (t > 10 Gyr) stellar populations. Using the NIR, we find the nucleus to be dominated by old stellar populations, and a circumnuclear ring with younger (∼2.5 Gyr) stars. We also combined the optical and NIR datacubes and performed a panchromatic spatially resolved stellar population synthesis, which resulted in a dominance of older stellar populations, in agreement with optical results. We argue that the technique of combining optical and NIR data might be useful to isolate the contribution of stellar population ages with strong NIR absorption bands. We also derive the stellar kinematics and find that the stellar motions are dominated by a high (∼240 km s−1) velocity dispersion in the nucleus, with stars also rotating around the centre. Lastly, we measure the absorption bands, both in the optical and in the NIR, and find a nuclear drop in their equivalent widths. The favoured explanation for this drop is a featureless continuum emission from the low luminosity active galactic nucleus. [ABSTRACT FROM AUTHOR]

We present a spatially resolved stellar population study of the inner ∼200 pc radius of NGC 4303 based on near-infrared integral field spectroscopy with SINFONI/VLT at a spatial resolution of 40–80 pc and using the starlight code. We found that the distribution of the stellar populations presents a spatial variation, suggesting an age stratification. Three main structures stand out. Two nuclear blobs, one composed by young stars (t ≤ 50 Myr) and one with intermediate-age stars (50 Myr < t ≤ 2 Gyr), both shifted from the centre. The third one is an internal intermediate-age spiral arm-like structure, surrounding the blob of young stars. Our results indicate that star formation has occurred through multiple bursts in this source. Furthermore, the youngest stellar populations (t ≲ 2 Gyr) are distributed along a circumnuclear star-forming ring with r ∼ 250 pc. The ring displays star formation rates (SFRs) in the range of 0.002–0.14 M⊙yr−1, favouring the 'pearls-on-a-string' scenario. The old underlying bulge stellar population component (t > 2 Gyr) is distributed outside the two blob structures. For the nuclear region (inner ∼60 pc radius) we derived an SFR of 0.43 M⊙ yr−1 and found no signatures of non-thermal featureless continuum and hot dust emission, supporting the scenario in which an LLAGN/LINER-like source is hidden in the centre of NGC 4303. Thus, our results reveal a rather complex star formation history in NGC 4303, with different stellar population components coexisting with a low efficiency accreting black hole in its centre. [ABSTRACT FROM AUTHOR]