scholarly journals Where the active galaxies live: a panchromatic view of radio-AGN in the AKARI-NEP field

2012 ◽  
Vol 8 (S295) ◽  
pp. 270-270
Author(s):  
Marios Karouzos ◽  
Myungshin Im ◽  
Markos Trichas ◽  
Keyword(s):  
Star Formation ◽  
Active Galaxies ◽  
Host Galaxy ◽  
Radio Sources ◽  
Relative Importance ◽  
Host Galaxies ◽  
Star Formation Activity ◽  
Multi Wavelength

AbstractWe study the host galaxy properties of radio sources in the AKARI-North Ecliptic Pole (NEP) field, using an ensemble of multi-wavelength datasets. We identify both radio-loud and radio-quiet AGN and study their host galaxy properties by means of SED fitting. We investigate the relative importance of nuclear and star-formation activity in radio-AGN and assess the role of radio-AGN as efficient quenchers of star-formation in their host galaxies.

scholarly journals Host galaxy properties of radio selected AGN

2013 ◽  
Vol 9 (S304) ◽  
pp. 343-344
Author(s):  
M. Bonzini ◽  
V. Mainieri ◽  
P. Padovani ◽  
K. I. Kellermann ◽  
N. Miller ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Far Infrared ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Star Forming ◽  
Star Formation Activity ◽  
Multi Wavelength ◽  
Deep Sample ◽  
Stellar Masses

AbstractWith the goal of investigating the link between black hole (BH) and star formation (SF) activity, we study a deep sample of radio selected star forming galaxies (SFGs) and active galactic nuclei (AGNs). Using a multi-wavelength approach we characterize their host galaxies properties (stellar masses, optical colors, and morphology). Moreover, comparing the star formation rate derived from the radio and far-infrared luminosity, we found evidences that the main contribution to the radio emission in the radio-quiet AGNs is star-formation activity in their host galaxy.

scholarly journals Through the kaleidoscope: star formation the host galaxies of radio-AGN

2013 ◽  
Vol 9 (S304) ◽  
pp. 323-326
Author(s):  
Marios Karouzos ◽  
Myungshin Im ◽  
Markos Trichas ◽  
Tomo Goto ◽  
Matt Malkan ◽  
...  
Keyword(s):  
Star Formation ◽  
Feedback Mechanism ◽  
Host Galaxy ◽  
Radio Sources ◽  
Radio Luminosity ◽  
Powerful Radio ◽  
Host Galaxies ◽  
Radio Jets ◽  
The North ◽  
Multi Wavelength

AbstractThere exist strong evidence supporting the co-evolution of central supermassive black holes and their host galaxies; however it is still under debate how such a relation comes about and whether it is relevant for all or only a subset of galaxies. A rich multi-wavelength dataset is available for the North Ecliptic Pole field, most notably surveyed by the AKARI infrared space telescope. We investigate the star-formation properties of the host galaxies of radio-AGN together with the radio feedback mechanism, potentially responsible for the eventual quenching of star formation. Using broadband SED modelling, the nuclear and host galaxy components of these sources are studied as a function of their radio luminosity. Here we present results concerning the AGN content of the radio sources in this field, while offering evidence supporting a “maintenance” type of feedback from powerful radio-jets.

scholarly journals Molecular gas in the central region of NGC 7213

2020 ◽  
Vol 641 ◽  
pp. A151
Author(s):  
F. Salvestrini ◽  
C. Gruppioni ◽  
F. Pozzi ◽  
C. Vignali ◽  
A. Giannetti ◽  
...  
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Large Scale ◽  
Host Galaxy ◽  
Molecular Gas ◽  
X Ray ◽  
Gas Kinematics ◽  
Star Formation Activity ◽  
Multi Wavelength

We present a multi-wavelength study (from X-ray to mm) of the nearby low-luminosity active galactic nucleus NGC 7213. We combine the information from the different bands to characterise the source in terms of contribution from the AGN and the host-galaxy interstellar medium. This approach allows us to provide a coherent picture of the role of the AGN and its impact, if any, on the star formation and molecular gas properties of the host galaxy. We focused our study on archival ALMA Cycle 1 observations, where the CO(2–1) emission line has been used as a tracer of the molecular gas. Using the 3DBAROLO code on ALMA data, we performed the modelling of the molecular gas kinematics traced by the CO(2–1) emission, finding a rotationally dominated pattern. The molecular gas mass of the host galaxy was estimated from the integrated CO(2–1) emission line obtained with APEX data, assuming an αCO conversion factor. Had we used the ALMA data, we would have underestimated the gas masses by a factor ∼3, given the filtering out of the large-scale emission in interferometric observations. We also performed a complete X-ray spectral analysis on archival observations, revealing a relatively faint and unobscured AGN. The AGN proved to be too faint to significantly affect the properties of the host galaxy, such as star formation activity and molecular gas kinematics and distribution.

scholarly journals The Starburst – AGN Connection: a Critical Review

2011 ◽  
Vol 20 (3) ◽  
Author(s):  
P. Rafanelli ◽  
G. La Mura ◽  
D. Bindoni ◽  
S. Ciroi ◽  
V. Cracco ◽  
...  
Keyword(s):  
Star Formation ◽  
Active Galaxies ◽  
Host Galaxy ◽  
Nuclear Activity ◽  
Massive Black Holes ◽  
Star Forming ◽  
Spectral Signatures ◽  
Star Formation Activity ◽  
Nuclear Regions

AbstractNuclear activity and star formation processes represent two key elements in the evolution of galaxies across the cosmic ages. In spite of very different physical backgrounds, several arguments suggest that they should be closely connected. On the basis of simple theoretical considerations, the transport of appreciable amounts of fuel to the AGN scale is very likely to trigger star formation in the gas. Young stellar populations, in their turn, are expected to affect the properties of the interstellar medium, leading to a complex balance of interactions among nuclear activity and star formation. This scenario is also supported by the observation of super-massive black holes and host galaxy properties, which strongly suggest a common evolutionary track. However, despite several years of extensive investigation, the relationship among the two processes still has to be properly explained. Here we provide a review of some of the most important observations, which are relevant to the issue of the connection among AGN and starburst events. Based on a wide sample of observations, we present an analysis of the spectral signatures connected with AGN and star formation activity. Expanding the concept of the distinction among star forming galaxies and the true active nuclei, we provide systematic evidence for a role of recent starburst events in the circum-nuclear regions of active galaxies and discuss the possibility of its influence onto the AGN environment. We also analyze the age, mass and metallicity properties of star-forming and active galaxies, illustrating that they are arranged in a sequence that is consistent with the identified relation.

scholarly journals A Possible Detection of CO (J = 3–2) Emission From the Host Galaxy of GRB 980425 with Atacama Submillimeter Telescope Experiment

2006 ◽  
Vol 2 (S235) ◽  
pp. 312-312
Author(s):  
Bunyo Hatsukade ◽  
Kotaro Kohno ◽  
Akira Endo ◽  
Tomoka Tosaki ◽  
Kouji Ohta ◽  
...  
Keyword(s):  
Star Formation ◽  
Gamma Ray ◽  
Line Emission ◽  
Emission Feature ◽  
Star Formation History ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Long Duration ◽  
The Galaxy ◽  
Multi Wavelength

AbstractLong-duration gamma-ray bursts (GRBs) are considered to be due to the death of massive stars. Therefore, GRBs are closely associated with the star formation of host galaxies. Since GRBs can be detected at cosmological distances, they are expected to be probes of the star formation history of the Universe. In order to determine the use of GRBs, it is essential to understand the star formation of their hosts. Multi-wavelength observations have shown that the star formation rates (SFRs) of GRB hosts derived from submillimeter/radio observations are generally higher than those from optical/UV observations (Berger et al. 2003). This implies that GRB hosts have a large amount of molecular gas and massive star formation obscured by dust. In order to solve this problem, it is necessary to derive the SFRs in a method which is independent of existing methods and not affected by dust extinction.We observed 12CO (J = 3–2) line emission from the host galaxy of GRB 980425 using the Atacama Submillimeter Telescope Experiment (ASTE). Five points were observed covering the entire region of the galaxy, and we find possible emission features (S/N ~ 3 σ) at the velocity range corresponding to the redshift of the galaxy. By combining all spectra of five points, we obtain a global spectrum with a ~4 σ emission feature. If the features are real, this is the first detection of CO among GRB hosts. We derive the total gas mass of M(H2)=7 ± 2× 108M⊙ assuming a CO-to-H2 conversion factor of αCO = 8.0M⊙ (K km s−1 pc2)−1, which is deduced using the correlation between the αCO and the metallicity. The dynamical mass is calculated to be Mdyn=2× 1010M⊙, and M(H2)/Mdyn~3% is consistent with those of nearby dwarfs and normal spirals. The derived SFR is 0.5 ± 0.1 M⊙ yr−1 based on the Schmidt law. This SFR agrees with the results of previous Hα observations, suggesting that there is no significant obscured star formation in this host galaxy. This result implies that there is a variety of GRB hosts in terms of the presence of obscured star formation.

scholarly journals 1.8. Evolutionary population synthesis of AGN host galaxy spectra

1998 ◽  
Vol 184 ◽  
pp. 31-32
Author(s):  
W. Kollatschny ◽  
A. Goerdt
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Active Galaxies ◽  
Evolutionary Synthesis ◽  
Host Galaxy ◽  
Synthesis Methods ◽  
Population Synthesis ◽  
Host Galaxies

We compute the stellar population of nearby Seyfert host galaxies and non-active galaxies using population and evolutionary synthesis methods. We find indication of enhanced star formation rates in the host-galaxies of AGN - especially in the circumnuclear regions of Seyfert 2 galaxies.

scholarly journals Stellar populations in hosts of giant radio galaxies and their neighbouring galaxies

2019 ◽  
Vol 624 ◽  
pp. A91 ◽  
Author(s):  
A. Kuźmicz ◽  
B. Czerny ◽  
C. Wildy
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Intergalactic Medium ◽  
Spectral Synthesis ◽  
Control Sample ◽  
Stellar Populations ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Radio Sources ◽  
Host Galaxies

Context. Giant radio galaxies (with projected linear size of radio structure larger than 0.7 Mpc) are very rare and unusual objects. Only ∼5% of extended radio sources reach such sizes. Understanding of the processes responsible for their large sizes is crucial to further our knowledge about the radio source’s evolution. Aims. We check the hypothesis that giants become extremely large due to the specific history of their host galaxy formation, as well as in the context of the cluster or group of galaxies where they evolve. Therefore we study the star formation histories in their host galaxies and in galaxies located in their neighbourhood. Methods. We studied 41 giant-size radio galaxies as well as galaxies located within a radius of 5 Mpc around giants to verify whether the external conditions of the intergalactic medium somehow influence the internal evolution of galaxies in the group/cluster. We compared the results with a control sample of smaller-sized Fanaroff–Riley type II radio galaxies and their neighbouring galaxies. We fit stellar continua in all galaxy spectra using the spectral synthesis code STARLIGHT and provide statistical analysis of the results. Results. We find that hosts of giant radio galaxies have a larger amount of intermediate age stellar populations compared with smaller-sized FRII radio sources. The same result is also visible when we compare neighbouring galaxies located up to 1.5 Mpc around giants and FRIIs. This may be evidence that star formation in groups with giants was triggered due to global processes occurring in the ambient intergalactic medium. These processes may also contribute to mechanisms responsible for the extremely large sizes of giants.

scholarly journals Searching for signs of jet-driven negative feedback in the nearby radio galaxy UGC 05771

2019 ◽  
Vol 489 (4) ◽  
pp. 4944-4961 ◽  
Author(s):  
Henry R M Zovaro ◽  
Nicole P H Nesvadba ◽  
Robert Sharp ◽  
Geoffrey V Bicknell ◽  
Brent Groves ◽  
...  
Keyword(s):  
Star Formation ◽  
Radio Source ◽  
Large Fraction ◽  
Host Galaxy ◽  
Radio Sources ◽  
Host Galaxies ◽  
Ionized Gas ◽  
Spectrum Radio ◽  
Hydrodynamical Simulations ◽  
Jet Plasma

ABSTRACT Hydrodynamical simulations predict that the jets of young radio sources can inhibit star formation in their host galaxies by injecting heat and turbulence into the interstellar medium (ISM). To investigate jet–ISM interactions in a galaxy with a young radio source, we have carried out a multiwavelength study of the z = 0.025 Compact Steep Spectrum radio source hosted by the early-type galaxy UGC 05771. Using Keck/OSIRIS observations, we detected H2 1–0 S(1) and [Fe ii] emission at radii of 100s of parsecs, which traces shocked molecular and ionized gas being accelerated outwards by the jets to low velocities, creating a ‘stalling wind’. At kpc radii, we detected shocked ionized gas using observations from the CALIFA survey, covering an area much larger than the pc-scale radio source. We found that existing interferometric radio observations fail to recover a large fraction of the source’s total flux, indicating the likely existence of jet plasma on kpc scales, which is consistent with the extent of shocked gas in the host galaxy. To investigate the star formation efficiency in UGC 05771, we obtained IRAM CO observations to analyse the molecular gas properties. We found that UGC 05771 sits below the Kennicutt–Schmidt relation, although we were unable to definitively conclude if direct interactions from the jets are inhibiting star formation. This result shows that jets may be important in regulating star formation in the host galaxies of compact radio sources.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A16 ◽  
Author(s):  
Andrew Butler ◽  
Minh Huynh ◽  
Ivan Delvecchio ◽  
Anna Kapińska ◽  
Paolo Ciliegi ◽  
...  
Keyword(s):  
Star Formation ◽  
Spectral Energy Distribution ◽  
Optical Emission ◽  
Radio Galaxies ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Radio Sources ◽  
Source Population ◽  
Host Galaxies ◽  
X Ray

The classification of the host galaxies of the radio sources in the 25 deg2 ultimate XMM extragalactic survey south field (XXL-S) is presented. XXL-S was surveyed at 2.1 GHz with the Australia Telescope Compact Array (ATCA) and is thus far the largest area radio survey conducted down to rms flux densities of σ ~ 41 μJy beam−1. Of the 6287 radio sources in XXL-S, 4758 (75.7%) were cross-matched to an optical counterpart using the likelihood ratio technique. There are 1110 spectroscopic redshifts and 3648 photometric redshifts available for the counterparts, of which 99.4% exist out to z ~ 4. A number of multiwavelength diagnostics, including X-ray luminosities, mid-infrared colours, spectral energy distribution fits, radio luminosities, and optical emission lines and colours, were used to classify the sources into three types: low-excitation radio galaxies (LERGs), high-excitation radio galaxies (HERGs), and star-forming galaxies (SFGs). The final sample contains 1729 LERGs (36.3%), 1159 radio-loud HERGs (24.4%), 296 radio-quiet HERGs (6.2%), 558 SFGs (11.7%), and 1016 unclassified sources (21.4%). The XXL-S sub-mJy radio source population is composed of ~75% active galactic nuclei and ~20% SFGs down to 0.2 mJy. The host galaxy properties of the HERGs in XXL-S are independent of the HERG selection, but the XXL-S LERG and SFG selection is, due to the low spectral coverage, largely determined by the known properties of those populations. Considering this caveat, the LERGs tend to exist in the most massive galaxies with low star formation rates and redder colours, whereas the HERGs and SFGs exist in galaxies of lower mass, higher star formation rates, and bluer colours. The fraction of blue host galaxies is higher for radio-quiet HERGs than for radio-loud HERGs. LERGs and radio-loud HERGs are found at all radio luminosities, but radio-loud HERGs tend to be more radio luminous than LERGs at a given redshift. These results are consistent with the emerging picture in which LERGs exist in the most massive quiescent galaxies typically found in clusters with hot X-ray halos and HERGs are associated with ongoing star formation in their host galaxies via the accretion of cold gas.

Distant quasar host galaxies and their environments with multi-wavelength 3D spectroscopy

2020 ◽  
Vol 15 (S359) ◽  
pp. 78-81
Author(s):  
Andrey Vayner
Keyword(s):  
Adaptive Optics ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Star Forming ◽  
Multi Wavelength ◽  
Integral Field Spectrograph ◽  
Guide Star ◽  
Laser Guide

AbstractWe have conducted a multi-wavelength survey of distant (1.3 < z < 2.6) luminous quasars host galaxies using the Keck integral field spectrograph (IFS) OSIRIS and laser guide star adaptive optics (LGS-AO) system, ALMA, HST and VLA. Studying distant quasar host galaxies is essential for understanding the role of active galactic nuclei (AGN) feedback on the interstellar medium (ISM), and its capability of regulating the growth of massive galaxies and their supermassive black holes (SMBH). The combination of LGS-AO and OSIRIS affords the necessary spatial resolution and contrast to disentangle the bright quasar emission from that of its faint host galaxy. We resolve the nebular emission lines, [OIII], [NII],, and [SII] at a sub-kiloparsec resolution to study the distribution, kinematics, and dynamics of the warm-ionized ISM in each quasar host galaxy. The goal of the survey was to search for ionized outflows and relate their spatial extent and energetics to the star-forming properties of the host galaxy. Combining ALMA and OSIRIS, we directly test whether outflows detected with OSIRIS are affecting the molecular ISM. We find that several mechanisms are responsible for driving the outflows within our systems, including radiation pressure in low and high column density environments as well as adiabatic and isothermal shocks driven by the quasar. From line ratio diagnostics, we obtain resolved measurements of the photoionization mechanisms and the gas-phase metallicity. We find that the quasars are responsible for photoionizing the majority of the ISM with metalicities lower than that of gas photoionized by AGN in the low redshift systems. We are now obtaining detailed observations of the circumgalactic medium (CGM) of these systems with the Keck Cosmic Web Imager (KCWI). The gas in the CGM may play an essential role in the evolution of these galaxies.

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