Found 80 talks width keyword galaxy evolution

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Thursday July 14, 2022
Dr. Jorge Sanchez-Almeida
IAC

Abstract

With the aim of detecting cosmological gas accretion onto galaxies of the local Universe, we examined the Ha emission in the halo of the 164 galaxies in the field of view of MUSE-Wide (Urrutia+19) with observable Ha (redshift < 0.42).  An exhaustive screening of the Ha images led us to select 118 reliable Ha emitting gas clouds. To our surprise, around 38 % of the time the Ha line profile shows a double peak centered at the rest-frame of the corresponding galaxy. We have explored several physical scenarios to explain this Ha emission, among which accretion disks around rogue  intermediate mass black holes (IMBHs) fit the observations best. I will describe the data analysis (to discard, e.g, instrumental artifacts and high redshift interlopers), the properties of the Ha emitting clumps (their fluxes, peak separation, and spatial distribution with respect to the central galaxy), and the arguments leading to the IMBH hypothesis rather than other alternatives (e.g., cosmological gas, expanding bubbles, or shocks in the circum galactic medium).


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Thursday May 19, 2022
Dr. Ignacio Martin-Navarro
IAC

Abstract

Black hole feedback is central to our theoretical understanding of galaxies. The energy and momentum radiated by growing supermassive black holes is expected to regulate the baryonic cycle, in particular, within massive dark matter halos, modulating gas cooling and thus star formation. Observational evidence of the role of black hole feedback remains, however, scarce, casting serious doubt on our current galaxy formation modelling. In this talk I will summarize our recent efforts trying to empirically characterize the effect of black hole feedback on galactic scales. I will describe how the combination of detailed stellar population analysis and well-known scaling relations can be used to actually constrain the physical processes behind black hole feedback. Moreover, I will also present evidence of black hole feedback acting beyond the host galaxy, further supporting the importance of black hole feedback in regulating the evolution of galaxies.


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Thursday April 21, 2022
Dr. Robert Grand
IAC

Abstract

Recent years have seen impressive development in cosmological simulations for spiral disc galaxies like the Milky Way. I present a suite of high-resolution magneto-hydrodynamic simulations that include many physical processes relevant for galaxy formation, including star formation, stellar evolution and feedback, active galactic nuclei and magnetic fields. I will discuss how these processes affect the formation of galactic discs, and what these simulations can tell us about the formation of the Milky Way, such as the properties of the Galaxy's putative last significant merger and its effect on the formation of the thick disc and stellar halo. 


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Thursday December 2, 2021
Prof. Roberto Maiolino
Kavli Cambridge

Abstract

In the local universe most of the stellar mass is in passive galaxies, where star formation is
absent or at very low levels. Understanding what are the mechanisms that have been
responsible for quenching star formation in galaxies, and transforming them into passive,
quiescent systems, is one of the main observational and theoretical challenges of extragalactic
astrophysics. I will give a brief overview of the several possible quenching causes and physical
processes that have been proposed so far, ranging from feedback from black hole accretion and
starburst activity, to effects associated with the large scale environment in which galaxies live.
Although most of these mechanisms and causes play a role in different classes of galaxies and
at different epochs, multi-band observations are providing growing evidences that just a few of
them play the key, dominant role.
I will conclude by providing prospects for further investigating these aspects and tackling open
questions with the next generation of observing facilities.


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Thursday May 27, 2021
Dr. Manuela Bischetti
INAF/Trieste

Abstract

This talk will be dedicated to luminous (LBol~1E47 erg/s),
high-redshift quasars, which are ideal targets to investigate (i) feedback
from SMBHs, and (ii) the early growth phases of giant galaxies. I will
present evidence of  SMBH-driven outflows  at all Cosmic epochs, back to
the early Universe. These outflows involve all gas phases (molecular,
neutral, ionised) and extend on nuclear to galactic and circum-galactic
scales. I will report on the first systematic study of the molecular gas
properties in the host-galaxies of the most luminous quasars, fundamental
to probe the impact of SMBH feedback on the host-galaxy evolution. I will
show that luminous quasars pinpoint high-density sites where giant galaxies
assemble, and I will discuss the major contribution of mergers to the final
galaxy mass. To this aim, I will present a wealth of multi-wavelength (UV
to sub-millimeter) observations from the WISE/SDSS hyper-luminous quasars
survey  at z~2-5 (WISSH), and recent results from the ESO large program
XQR-30, the Ultimate X-SHOOTER Legacy Survey of Quasars at the Reionization
epoch.

 


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Tuesday June 9, 2020
Prof. Mariangela Bernardi
University of Pennsylvania

Abstract

Stellar populations vary across the galaxy population. However, even within a single galaxy, there are stellar population gradients which spatially resolved spectroscopic studies are beginning to reveal. The MaNGA survey permits a study of gradients in a sample of early-type galaxies which is nearly two orders of magnitude larger than previous work. This allows us to quantify the effects of gradients on estimates of the stellar and dynamical masses of these galaxies, and to study how age and abundance gradients, and thus star formation and assembly histories, vary across the population. In this talk I will present results from our recent analysis.

 

zoom link: https://rediris.zoom.us/j/97614680345


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Thursday May 28, 2020
Prof. Avishai Dekel
Hebrew University of Jerusalem

Abstract

This talk will address the preferred mass and time for galaxy formation, in dark-matter haloes similar to that of the Milky way but when the Universe was a few Gigayears old. It is proposed that this is due to the interplay between two mechanisms, first *supernova* feedback that removes gas from the galaxy, and second *hot gas* in the deep potential well of massive haloes that suppresses cold gas supply to the galaxy, the two being effective in galaxies of lower and higher masses respectively. Cosmological simulations reveal that the same mechanisms are responsible for a robust sequence of events were galaxies undergo a dramatic gaseous *compaction*, sometimes caused by mergers, into a compact star-forming “blue nugget”. This triggers inside-out *quenching* of star formation, which is maintained by a hot massive halo aided by black-hole feedback, leading to todays passive elliptical galaxies. The blue-nugget phase is responsible for drastic transitions in the main galaxy structural, kinematic and compositional properties. In particular, the growth of the *black hole* in the galaxy center, first suppressed by supernova feedback when below the critical mass, is boosted by the compaction event and keeps growing once the halo is massive enough to lock the supernova ejecta by its deep potential well and the hot halo. The compaction events also trigger the formation of extended rings in high-z massive galaxies. These events all occur near the same characteristic halo mass, giving rise to the highest efficiency of galaxy formation and black-hole growth at this magic mass and time.

 

Zoom link:  https://rediris.zoom.us/j/98813487304


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Thursday June 13, 2019
Dr. Jorge Sanchez Almeida
IAC

Abstract

Although the name 'fundamental metallicity relation' (FMR) may sound a bit bombastic, it really represents a fundamental relation in the sense of revealing a fundamental process in galaxy formation. Numerical simulations predict that accretion of cosmic web gas feeds star formation in star-forming galaxies. However, this solid theoretical prediction has been extremely elusive to confirm. The FMR, i.e., the fact that galaxies of the same stellar mass but larger star formation rate (SFR) tend to have smaller gas-phase metallicity (Zg), is one of the best observational supports available yet. The talk will introduce the FMR and then present recent results of our group showing how the FMR emerges from a local anti-correlation between SFR and Zg existing in the disks of galaxies. Thus, understanding the FMR is equivalent to understanding why active star-forming regions tend to have low relative metallicity. The existence of the local anti-correlation SFR-vs-Zg is found by Sanchez-Menguiano+19 ApJ  and Sanchez Almeida+18 MNRAS, whereas the equivalence between local and global laws is in Sanchez Almeida & Sanchez-Menguiano 19 ApJL.


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Thursday May 23, 2019
Patricia Sánchez Blázquez
Universidad Autónoma de Madrid

Abstract

The Time Inference with MUSE in Extragalactic Rings, TIMER, is a project dedicated to study the central regions
of 24 nearby galaxies with the integral field spectrograph MUSE. The spatial resolution of this instruments
allows the detailed study of the different structural components in these galaxies and, therefore, disentangle
their star formation histories, kinematics and dynamics of both, the gaseous and the stellar constituents.
In this talk, I will give an overview of the project as well as some details on  how the  dataset can be used for a plethora of scientific applications, like
understanding the stellar and AGN feedback, the role of primary and secondary bars, the dynamics of nuclear
spiral arms, barlenses, box/peanuts and bulges.


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Wednesday November 28, 2018
Fernando Buitrago
Institute of Astrophysics and Space Sciences (IA)

Abstract

There are galaxies that remain untouched since the ancient
Universe. These unique objects, the so-called relic galaxies, are several times
more massive than our Milky Way but with much smaller sizes, and
containing very old (>10 Gyr) stellar populations. For the very few of
them already found and analysed (most of them by our IAC colleagues),
they seem to host "too heavy" central
super massive black holes, also displaying an overabundance of low mass
versus high mass stars and retaining their primeval morphologies and
kinematics. How did they survive until the present day? Simulations
predict that they reside in galaxy overdensities whose large internal
random motions prevent galaxies from merging. However, we have not yet
determined observationally neither the environments these galaxies
inhabit nor how many there are (their number densities). We make use
of the GAMA survey, that allows us to conduct a complete
census of this elusive galaxy population, because of its large area and
spectroscopic completeness. After inspecting 180 square degrees of the sky
using the deepest photometric images available, we identified 29
massive ultracompact galaxies in the nearby Universe (0.02 < z < 0.3),
that are true windows to the ancient Universe. I will present the first paper
about this exceptional sample, describing their properties and
highlighting the fact that while some galaxies seem to be satellites
of bigger objects, others are not located in clusters, at odds with the
theoretical expectations.


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