Quasar host galaxies and environments in the GAMA survey

2019 ◽  
Vol 15 (S356) ◽  
pp. 170-170
Author(s):  
Jari Kotilainen
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Group Membership ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Cluster Group ◽  
First Results ◽  
Triggering Mechanisms ◽  
Mass Assembly

AbstractWe present first results from our study of the host galaxies and environments of quasars in Galaxy And Mass Assembly (GAMA), a multiwavelength photometric and spectroscopic survey for ∼300,000 galaxies over ∼300 deg2, to a limiting magnitude of r ∼ 20 mag. We use a GAIA-selected sample of ∼350 quasars at z < 0.3 in GAMA. For all the quasars, we determine all surrounding GAMA galaxies and measure their star formation (SF) rate and SF history, and the host galaxy morphology and group membership of the quasars. As a comparison sample of inactive galaxies, we use 1000 subsets of galaxies in GAMA, matched in redshift and galaxy stellar mass to the quasars. We find that quasar activity does not depend on the large-scale environment (cluster/group/void), although quasars tend to prefer satellite location in their environment. Compared to inactive galaxies, quasars are preferentially hosted in bulge-dominated galaxies and have higher SF rates, both overall and averaged over the last 10 and 100 Myr. Quasars also have shorter median SF timescales, shorter median time since the last SF burst, and higher metallicity than inactive galaxies. We discuss these results in terms of triggering mechanisms of the quasar activity and the role of quasars in galaxy evolution.

scholarly journals Properties of Radio Source Host Galaxies

2003 ◽  
Vol 20 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Wim de Vries
Keyword(s):  
Radio Source ◽  
Large Scale ◽  
Radio Galaxy ◽  
Host Galaxy ◽  
Host Galaxies ◽  
State Of Affairs

AbstractA brief overview of the current radio source host galaxy state of affairs is given. All the evidence appears to point towards a scenario in which the young radio source expands through the host galaxy on timescales of 105–106 yr, before it ends its life as a large scale FR II radio galaxy. The place and role of the quasars in this evolutionary picture is unclear, however, and remains an issue of debate.

scholarly journals Do AGN triggering mechanisms vary with radio power? – I. Optical morphologies of radio-intermediate HERGs

2019 ◽  
Vol 487 (4) ◽  
pp. 5490-5507 ◽  
Author(s):  
J C S Pierce ◽  
C N Tadhunter ◽  
C Ramos Almeida ◽  
P S Bessiere ◽  
M Rose
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Elliptical Galaxy ◽  
Optical Emission ◽  
Imaging Data ◽  
High Excitation ◽  
Late Type ◽  
Host Galaxies ◽  
Triggering Mechanisms ◽  
Radio Power

ABSTRACT Active galactic nuclei (AGNs) with intermediate radio powers are capable of driving multiphase outflows in galaxy bulges, and are also more common than their high-radio-power counterparts. In-depth characterization of the typical host galaxies and likely triggering mechanisms for this population is therefore required in order to better understand the role of radio AGN feedback in galaxy evolution. Here, we use deep optical imaging data to study the detailed host morphologies of a complete sample of 30 local radio AGNs with high-excitation optical emission (HERG) spectra and intermediate radio powers [ z < 0.1; 22.5 < log($L_{\rm 1.4GHz}$) < 24.0 W Hz-1]. The fraction of hosts with morphological signatures of mergers and interactions is greatly reduced compared to the 2Jy radio-powerful galaxies [log($L_{\rm 1.4GHz}$) > 25.0 W Hz-1] with strong optical emission lines: 53 ± 9 per cent compared with 94 ± 4 per cent. In addition, the most radio-powerful half of the sample has a higher frequency of morphological disturbance than the least radio-powerful half (67 ± 12 per cent and 40 ± 13 per cent, respectively), including the eight most highly disturbed galaxies. This suggests that the importance of triggering nuclear activity in high-excitation radio galaxies (HERGs) through mergers and interactions reduces with radio power. Both visual inspection and detailed light profile modelling reveal a mixed population of early-type and late-type morphologies, contrary to the massive elliptical galaxy hosts of radio-powerful AGNs. The prevalence of late-type hosts could suggest that triggering via secular, disc-based processes has increased importance for HERGs with lower radio powers (e.g. disc instabilities and large-scale bars).

scholarly journals The role of scatter and satellites in shaping the large-scale clustering of X-ray AGN as a function of host galaxy stellar mass

2021 ◽  
Author(s):  
A Viitanen ◽  
V Allevato ◽  
A Finoguenov ◽  
F Shankar ◽  
C Marsden
Keyword(s):  
Large Scale ◽  
Theoretical Models ◽  
Stellar Mass ◽  
Current Data ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Mass Scaling ◽  
Clustering Data ◽  
Semi Empirical

Abstract The co-evolution between central supermassive black holes (BH), their host galaxies, and dark matter haloes is still a matter of intense debate. Present theoretical models suffer from large uncertainties and degeneracies, for example, between the fraction of accreting sources and their characteristic accretion rate. In recent work we showed that Active Galactic Nuclei (AGN) clustering represents a powerful tool to break degeneracies when analysed in terms of mean BH mass, and that AGN bias at fixed stellar mass is largely independent of most of the input parameters, such as the AGN duty cycle and the mean scaling between BH mass and host galaxy stellar mass. In this paper we take advantage of our improved semi-empirical methodology and recent clustering data derived from large AGN samples at z ∼ 1.2, demonstrate that the AGN bias as a function of host galaxy stellar mass is a crucial diagnostic of the BH–galaxy connection, and is highly dependent on the scatter around the BH mass–galaxy mass scaling relation and on the relative fraction of satellite and central active BHs. Current data at z ∼ 1.2 favour relatively high values of AGN in satellites, pointing to a major role of disc instabilities in triggering AGN, unless a high minimum host halo mass is assumed. The data are not decisive on the magnitude/covariance of the BH-galaxy scatter at z ∼ 1.2 and intermediate host masses M⊙ ≲ 1011 M⊙. However, future surveys like Euclid/LSST will be pivotal in shedding light on the BH–galaxy co-evolution.

scholarly journals An ASKAP survey for H i absorption towards dust-obscured quasars

2019 ◽  
Vol 489 (4) ◽  
pp. 4926-4943 ◽  
Author(s):  
M Glowacki ◽  
J R Allison ◽  
V A Moss ◽  
E K Mahony ◽  
E M Sadler ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
Spectral Energy Distribution ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Neutral Medium ◽  
Host Galaxies ◽  
Gas Kinematics ◽  
Neutral Gas

ABSTRACT Obscuration of quasars by accreted gas and dust, or dusty intervening galaxies, can cause active galactic nuclei (AGN) to be missed in optically selected surveys. Radio observations can overcome this dust bias. In particular, radio surveys searching for H i absorption inform us on how the AGN can impact on the cold neutral gas medium within the host galaxy, or the population of intervening galaxies through the observed line of sight gas kinematics. We present the results of an H i absorption line survey at 0.4 &lt; z &lt; 1 towards 34 obscured quasars with the Australian SKA Pathfinder (ASKAP) commissioning array. We detect three H i absorption lines, with one of these systems previously unknown. Through optical follow-up for two sources, we find that in all detections the H i gas is associated with the AGN, and hence that these AGN are obscured by material within their host galaxies. Most of our sample are compact, and in addition, are either gigahertz peaked spectrum (GPS), or steep spectrum (CSS) sources, both thought to represent young or recently re-triggered radio AGN. The radio spectral energy distribution classifications for our sample agree with galaxy evolution models in which the obscured AGN has only recently become active. Our associated H i detection rate for GPS and compact SS sources matches those of other surveys towards such sources. We also find shallow and asymmetric H i absorption features, which agrees with previous findings that the cold neutral medium in compact radio galaxies is typically kinematically disturbed by the AGN.

scholarly journals Numerical simulations of galaxy evolution in cosmological context

2008 ◽  
Vol 4 (S254) ◽  
pp. 429-434
Author(s):  
Marie Martig ◽  
Frédéric Bournaud ◽  
Romain Teyssier
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Physical Processes ◽  
Cosmological Simulations ◽  
Cosmological Context ◽  
First Results ◽  
Gas Accretion ◽  
The Universe ◽  
Very High ◽  
Internal Evolution

AbstractLarge volume cosmological simulations succeed in reproducing the large-scale structure of the Universe. However, they lack resolution and may not take into account all relevant physical processes to test if the detail properties of galaxies can be explained by the CDM paradigm. On the other hand, galaxy-scale simulations could resolve this in a robust way but do not usually include a realistic cosmological context.To study galaxy evolution in cosmological context, we use a new method that consists in coupling cosmological simulations and galactic scale simulations. For this, we record merger and gas accretion histories from cosmological simulations and re-simulate at very high resolution the evolution of baryons and dark matter within the virial radius of a target galaxy. This allows us for example to better take into account gas evolution and associated star formation, to finely study the internal evolution of galaxies and their disks in a realistic cosmological context.We aim at obtaining a statistical view on galaxy evolution from z ≃ 2 to 0, and we present here the first results of the study: we mainly stress the importance of taking into account gas accretion along filaments to understand galaxy evolution.

scholarly journals Quasars, Feedback, and Galaxy Formation

2009 ◽  
Vol 5 (S267) ◽  
pp. 421-428
Author(s):  
Philip F. Hopkins
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Galaxy Formation ◽  
Theoretical Models ◽  
Light Curves ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Supermassive Black Hole ◽  
Analytic Models ◽  
Black Hole Masses

AbstractRecent observations of tight correlations between supermassive black hole masses and the properties of their host galaxies demonstrate that black holes and bulges are co-eval and have motivated theoretical models in which feedback from AGN activity regulates the black hole and host galaxy evolution. Combining simulations, analytic models, and recent observations, answers to a number of questions are starting to take shape: how do AGN get triggered? How long do they live? What are typical light curves and what sets them? Is feedback necessary and/or sufficient to regulate BH growth? What effects does that feedback have on the host galaxy? On the host halo? All of this also highlights questions that remain wide open: how does gas get from a few pc to the AGN? What are the actual microphysical mechanisms of feedback? What is the tradeoff between stellar and AGN feedback? And, if there are different “modes” of feedback, where/when are each important?

scholarly journals Probing the QSO host galaxy evolution through the gas metallicity

2012 ◽  
Vol 8 (S295) ◽  
pp. 269-269
Author(s):  
B. Husemann ◽  
L. Wisotzki ◽  
K. Jahnke ◽  
S. F. Sánchez ◽  
D. Nugroho
Keyword(s):  
Gas Phase ◽  
Galaxy Evolution ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Spatially Resolved ◽  
Gas Accretion

AbstractWe use the spatially resolved gas-phase metallicity as a new diagnostic for tagging recent interactions in QSO host galaxies. With this technique we also identified a QSO with extremely low gas-phase metallicity as likely evidence for gas accretion from the environment.

scholarly journals Quasar Metal Abundances & Host Galaxy Evolution

2009 ◽  
Vol 5 (S265) ◽  
pp. 171-178
Author(s):  
Fred Hamann ◽  
Leah E. Simon
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
High Redshift ◽  
Big Bang ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Massive Galaxies ◽  
Central Regions ◽  
Metal Abundances ◽  
The Big Bang

AbstractHigh-redshift quasars provide a unique glimpse into the early evolution of massive galaxies. The physical processes that trigger major bursts of star formation in quasar host galaxies (mergers and interactions) probably also funnel gas into the central regions to grow the super-massive black holes (SMBHs) and ignite the luminous quasar phenomenon. The globally dense environments where this occurs were probably also among the first to collapse and manufacture stars in significant numbers after the big bang. Measurements of the elemental abundances near quasars place important constraints on the nature, timing and extent of this star formation. A variety of studies using independent emission and absorption line diagnostics have shown that quasar environments have gas-phase metallicities that are typically a few times solar at all observed redshifts. These results are consistent with galaxy evolution scenarios in which large amounts of star formation (e.g., in the central regions) precede the visibly bright quasar phase. An observed trend for higher metallicities in more luminmous quasars (powered by more massive SMBHs) is probably tied to the well-known mass–metallicity relation among ordinary galaxies. This correlation and the absence of a trend with redshift indicate that mass is a more important parameter in the evolution than the time elapsed since the big bang.

scholarly journals The EDGE-CALIFA survey: exploring the role of molecular gas on galaxy star formation quenching

2020 ◽  
Vol 644 ◽  
pp. A97
Author(s):  
D. Colombo ◽  
S. F. Sanchez ◽  
A. D. Bolatto ◽  
V. Kalinova ◽  
A. Weiß ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Large Scale ◽  
Formation Rate ◽  
Molecular Gas ◽  
Star Forming ◽  
Average Value ◽  
First Results ◽  
Gas Consumption ◽  
Formation Efficiency

Understanding how galaxies cease to form stars represents an outstanding challenge for galaxy evolution theories. This process of “star formation quenching” has been related to various causes, including active galactic nuclei activity, the influence of large-scale dynamics, and the environment in which galaxies live. In this paper, we present the first results from a follow-up of CALIFA survey galaxies with observations of molecular gas obtained with the APEX telescope. Together with the EDGE-CARMA observations, we collected 12CO observations that cover approximately one effective radius in 472 CALIFA galaxies. We observe that the deficit of galaxy star formation with respect to the star formation main sequence (SFMS) increases with the absence of molecular gas and with a reduced efficiency of conversion of molecular gas into stars, which is in line with the results of other integrated studies. However, by dividing the sample into galaxies dominated by star formation and galaxies quenched in their centres (as indicated by the average value of the Hα equivalent width), we find that this deficit increases sharply once a certain level of gas consumption is reached, indicating that different mechanisms drive separation from the SFMS in star-forming and quenched galaxies. Our results indicate that differences in the amount of molecular gas at a fixed stellar mass are the primary drivers for the dispersion in the SFMS, and the most likely explanation for the start of star formation quenching. However, once a galaxy is quenched, changes in star formation efficiency drive how much a retired galaxy differs in its star formation rate from star-forming ones of similar masses. In other words, once a paucity of molecular gas has significantly reduced star formation, changes in the star formation efficiency are what drives a galaxy deeper into the red cloud, hence retiring it.

scholarly journals Fast Radio Bursts: An Extragalactic Enigma

2019 ◽  
Vol 57 (1) ◽  
pp. 417-465 ◽  
Author(s):  
James M. Cordes ◽  
Shami Chatterjee
Keyword(s):  
Radiation Energy ◽  
Compact Objects ◽  
Host Galaxy ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
Host Galaxies ◽  
Alternative Source ◽  
Propagation Effects ◽  
Source Models

We summarize our understanding of millisecond radio bursts from an extragalactic population of sources. Fast radio bursts (FRBs) occur at an extraordinary rate, thousands per day over the entire sky with radiation energy densities at the source about ten billion times larger than those from Galactic pulsars. We survey FRB phenomenology, source models and host galaxies, coherent radiation models, and the role of plasma propagation effects in burst detection. The FRB field is guaranteed to be exciting: New telescopes will expand the sample from the current ∼80 unique burst sources (and only a few secure localizations and redshifts) to thousands, with burst localizations that enable host-galaxy redshifts emerging directly from interferometric surveys. ▪ FRBs are now established as an extragalactic phenomenon. ▪ Only a few sources are known to repeat. Despite the failure to redetect other FRBs, they are not inconsistent with all being repeaters. ▪ FRB sources may be new, exotic kinds of objects or known types in extreme circumstances. Many inventive models exist, ranging from alien spacecraft to cosmic strings, but those concerning compact objects and supermassive black holes have gained the most attention. A rapidly rotating magnetar is a promising explanation for FRB 121102 along with the persistent source associated with it, but alternative source models are not ruled out for it or other FRBs. ▪ FRBs are powerful tracers of circumsource environments, “missing baryons” in the intergalactic medium (IGM), and dark matter. ▪ The relative contributions of host galaxies and the IGM to propagation effects have yet to be disentangled, so dispersion measure distances have large uncertainties.

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