scholarly journals On the Formation of the First Quasars

2017 ◽  
Vol 34 ◽  
Author(s):  
Rosa Valiante ◽  
Bhaskar Agarwal ◽  
Melanie Habouzit ◽  
Edwige Pezzulli
Keyword(s):  
Black Holes ◽  
Interstellar Medium ◽  
Chemical Evolution ◽  
Rapid Growth ◽  
State Of The Art ◽  
Theoretical Models ◽  
Host Galaxy ◽  
Subsequent Evolution ◽  
Review State ◽  
Fast Chemical

AbstractObservations of the most luminous quasars at redshift z > 6 reveal the existence of numerous supermasssive black holes (>199 M⊙) already in place about 12 billion years ago. In addition, the interstellar medium of the galaxies hosting these black holes are observed to be chemically mature systems, with metallicities (Z > Z⊙) and dust masses (>108 M⊙) similar to that of more evolved, local galaxies. The connection between the rapid growth of the first supermassive black holes and the fast chemical evolution of the host galaxy is one of the most puzzling issues for theoretical models. Here, we review state-of-the-art theoretical models that focus on this problem with particular emphasis on the conditions that lead to the formation of quasar seeds and their subsequent evolution at z ⩾ 6.

scholarly journals Chandra X-ray Observations of Dwarf Starburst Galaxies

2004 ◽  
Vol 217 ◽  
pp. 304-309
Author(s):  
Jürgen Ott ◽  
Fabian Walter ◽  
Elias Brinks ◽  
Ulrich Klein
Keyword(s):  
Interstellar Medium ◽  
Gravitational Potential ◽  
Thermal Plasma ◽  
Theoretical Models ◽  
Starburst Galaxies ◽  
Host Galaxy ◽  
X Ray ◽  
Hot Gas ◽  
Neutral Gas

We obtained X-ray observations for a sample of eight nearby dwarf starburst galaxies from the Chandra X-ray Observatory. Five galaxies of our sample show extended (size: 1-10 kpc), diffuse X-ray emission which can be attributed to a hot thermal plasma. This phase of the interstellar medium purportedly drives the expansion of supergiant shells. A comparison of the derived gas parameters with theoretical models reveals that the hot gas in principle is capable to escape from the gravitational potential of the host galaxy. However, the outflows appear to be contained in those cases where an extended envelope or massive tidal features of neutral gas exist.

scholarly journals Theoretical models of the Planetary Nebula populations in galaxies

1997 ◽  
Vol 180 ◽  
pp. 474-474 ◽  
Author(s):  
M. G. Richer ◽  
M. L. McCall ◽  
N. Arimoto
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Chemical Evolution ◽  
Planetary Nebula ◽  
Planetary Nebulae ◽  
Theoretical Models ◽  
Theoretical Modelling ◽  
Oxygen Abundance

We consider the possibility of using bright planetary nebulae to study the chemical evolution of their parent galaxies. In particular, we would like to use planetary nebulae as abundance probes in galaxies where star formation ended long ago, such as ellipticals or the bulges of spirals, and in which no other direct probes exist. However, if we are to use planetary nebulae to study the chemical evolution of their parent galaxies, we must relate the oxygen abundance in bright planetary nebulae to the oxygen abundance in the interstellar medium when star formation stopped. Obviously, only theoretical modelling can provide this information once star formation has stopped.

scholarly journals AGN feedback and star formation in ETGs: negative and positive feedback

2015 ◽  
Vol 11 (S315) ◽  
pp. 224-227 ◽  
Author(s):  
Luca Ciotti ◽  
Jeremiah P. Ostriker ◽  
Andrea Negri ◽  
Silvia Pellegrini ◽  
Silvia Posacki ◽  
...  
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Stellar Population ◽  
State Of The Art ◽  
Host Galaxy ◽  
Early Type ◽  
Spatial And Temporal Scales ◽  
Cooling Flows ◽  
The Galaxy ◽  
Hydrodynamical Simulations

AbstractAGN feedback from supermassive black holes (SMBHs) at the center of early type galaxies is commonly invoked as the explanation for the quenching of star formation in these systems. The situation is complicated by the significant amount of mass injected in the galaxy by the evolving stellar population over cosmological times. In absence of feedback, this mass would lead to unobserved galactic cooling flows, and to SMBHs two orders of magnitude more massive than observed. By using high-resolution 2D hydrodynamical simulations with radiative transport and star formation in state-of-the-art galaxy models, we show how the intermittent AGN feedback is highly structured on spatial and temporal scales, and how its effects are not only negative (shutting down the recurrent cooling episodes of the ISM), but also positive, inducing star formation in the inner regions of the host galaxy.

Impact of the Small-Scale Spatial Distribution of Dust Particles on the Chemical Evolution of the Diffuse Interstellar Medium

2020 ◽  
Vol 64 (8) ◽  
pp. 693-710
Author(s):  
V. A. Sokolova ◽  
A. I. Vasyunin ◽  
A. B. Ostrovskii ◽  
S. Yu. Parfenov
Keyword(s):  
Spatial Distribution ◽  
Interstellar Medium ◽  
Chemical Evolution ◽  
Dust Particles ◽  
Small Scale

scholarly journals Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars

2020 ◽  
Vol 501 (1) ◽  
pp. 269-280
Author(s):  
Xuheng Ding ◽  
Tommaso Treu ◽  
Simon Birrer ◽  
Adriano Agnello ◽  
Dominique Sluse ◽  
...  
Keyword(s):  
Black Holes ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Wide Field ◽  
Host Galaxies ◽  
Field Surveys ◽  
Instrumental Resolution ◽  
The Moment

ABSTRACT One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ($\mathcal {M}_{\rm BH}$) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution.

scholarly journals Constitutive Models for the Tensile Behaviour of TRM Materials: Literature Review and Experimental Verification

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 700
Author(s):  
Maria Concetta Oddo ◽  
Giovanni Minafò ◽  
Lidia La Mendola
Keyword(s):  
State Of The Art ◽  
Constitutive Models ◽  
Stress Transfer ◽  
Theoretical Models ◽  
Tensile Tests ◽  
Analytical Models ◽  
Tensile Behaviour ◽  
Tensile Response ◽  
Textile Reinforced Mortar ◽  
Inorganic Matrix

In recent years, the scientific community has focused its interest on innovative inorganic matrix composite materials, namely TRM (Textile Reinforced Mortar). This class of materials satisfies the need of retrofitting existing masonry buildings, by keeping the compatibility with the substrate. Different recent studies were addressed to improve the knowledge on their mechanical behaviour and some theoretical models were proposed for predicting the tensile response of TRM strips. However, this task is complex due to the heterogeneity of the constituent materials and the stress transfer mechanism developed between matrix and fabric through the interface in the cracked stage. This paper presents a state-of-the-art review on the existing constitutive models for the tensile behavior of TRM composites. Literature experimental results of tensile tests on TRM coupons are presented and compared with the most relevant analytical models proposed until now. Finally, a new experimental study is presented and its results are used to further verify the reliability of the literature expressions.

An accreting < 105M⊙ black hole at the center of dwarf galaxy IC750

2019 ◽  
Vol 15 (S356) ◽  
pp. 376-376
Author(s):  
Ingyin Zaw
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Host Galaxy ◽  
Scaling Relations ◽  
Host Galaxies ◽  
Seed Formation ◽  
Maser Emission ◽  
Water Masers

AbstractNuclear black holes in dwarf galaxies are important for understanding the low end of the supermassive black hole mass distribution and the black hole-host galaxy scaling relations. IC 750 is a rare system which hosts an AGN, found in ˜0.5% of dwarf galaxies, with circumnuclear 22 GHz water maser emission, found in ˜3–5% of Type 2 AGNs. Water masers, the only known tracer of warm, dense gas in the center parsec of AGNs resolvable in position and velocity, provide the most precise and accurate mass measurements of SMBHs outside the local group. We have mapped the maser emission in IC 750 and find that it traces a nearly edge-on warped disk, 0.2 pc in diameter. The central black hole has an upper limit mass of ˜1 × 105 M⊙ and a best fit mass of ˜8 × 104 M⊙, one to two orders of magnitude below what is expected from black hole-galaxy scaling relations. This has implications for models of black hole seed formation in the early universe, the growth of black holes, and their co-evolution with their host galaxies.

scholarly journals Simulating the interstellar medium of galaxies with radiative transfer, non-equilibrium thermochemistry, and dust

2020 ◽  
Vol 499 (4) ◽  
pp. 5732-5748 ◽  
Author(s):  
Rahul Kannan ◽  
Federico Marinacci ◽  
Mark Vogelsberger ◽  
Laura V Sales ◽  
Paul Torrey ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Galaxy Formation ◽  
State Of The Art ◽  
Complex Function ◽  
Ionization State ◽  
Radiation Fields ◽  
Stellar Feedback ◽  
Wide Range ◽  
Dust Distribution ◽  
Non Equilibrium

ABSTRACT We present a novel framework to self-consistently model the effects of radiation fields, dust physics, and molecular chemistry (H2) in the interstellar medium (ISM) of galaxies. The model combines a state-of-the-art radiation hydrodynamics module with a H  and He  non-equilibrium thermochemistry module that accounts for H2 coupled to an empirical dust formation and destruction model, all integrated into the new stellar feedback framework SMUGGLE. We test this model on high-resolution isolated Milky-Way (MW) simulations. We show that the effect of radiation feedback on galactic star formation rates is quite modest in low gas surface density galaxies like the MW. The multiphase structure of the ISM, however, is highly dependent on the strength of the interstellar radiation field. We are also able to predict the distribution of H2, that allow us to match the molecular Kennicutt–Schmidt (KS) relation, without calibrating for it. We show that the dust distribution is a complex function of density, temperature, and ionization state of the gas. Our model is also able to match the observed dust temperature distribution in the ISM. Our state-of-the-art model is well-suited for performing next-generation cosmological galaxy formation simulations, which will be able to predict a wide range of resolved (∼10 pc) properties of galaxies.

scholarly journals The radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 in a galaxy merger

2020 ◽  
Vol 496 (2) ◽  
pp. 1757-1765 ◽  
Author(s):  
Akihiro Doi ◽  
Motoki Kino ◽  
Nozomu Kawakatu ◽  
Kazuhiro Hada
Keyword(s):  
Black Holes ◽  
Near Infrared ◽  
Gamma Ray ◽  
Linear Structure ◽  
Seyfert Galaxies ◽  
Mass Function ◽  
High Mass ◽  
Host Galaxy ◽  
Supporting Evidence ◽  
Narrow Line

ABSTRACT The supermassive black holes (SMBHs) of narrow-line Seyfert 1 galaxies (NLS1s) are at the lower end of the mass function of active galactic nuclei (AGNs) and reside preferentially in late-type host galaxies with pseudobulges, which are thought to be formed by internal secular evolution. On the other hand, the population of radio-loud NLS1s presents a challenge for the relativistic jet paradigm, which states that powerful radio jets are associated exclusively with very high mass SMBHs in elliptical hosts, which are built up through galaxy mergers. We investigated distorted radio structures associated with the nearest gamma-ray-emitting, radio-loud NLS1, 1H 0323+342. This provides supporting evidence for the merger hypothesis based on past optical/near-infrared observations of its host galaxy. The anomalous radio morphology consists of two different structures: the inner curved structure of the currently active jet and an outer linear structure of low-brightness relics. Such coexistence might be indicative of the stage of an established black hole binary with precession before the black holes coalesce in the galaxy merger process. 1H 0323+342 and other radio-loud NLS1s under galaxy interactions may be extreme objects on the evolutionary path from radio-quiet NLS1s to normal Seyfert galaxies with larger SMBHs in classical bulges through mergers and merger-induced jet phases.

scholarly journals GRAVITY-WAVE DETECTORS AS PROBES OF EXTRA DIMENSIONS

2005 ◽  
Vol 14 (12) ◽  
pp. 2347-2353 ◽  
Author(s):  
CHRIS CLARKSON ◽  
ROY MAARTENS
Keyword(s):  
Black Holes ◽  
String Theory ◽  
Gravity Wave ◽  
Gravity Waves ◽  
Extra Dimensions ◽  
State Of The Art ◽  
Three Dimensional ◽  
Observable Universe ◽  
Dimensional Spacetime ◽  
Higher Dimensional

If string theory is correct, then our observable universe may be a three-dimensional "brane" embedded in a higher-dimensional spacetime. This theoretical scenario should be tested via the state-of-the-art in gravitational experiments — the current and upcoming gravity-wave detectors. Indeed, the existence of extra dimensions leads to oscillations that leave a spectroscopic signature in the gravity-wave signal from black holes. The detectors that have been designed to confirm Einstein's prediction of gravity waves, can in principle also provide tests and constraints on string theory.

Sign in / Sign up

Export Citation Format

Share Document