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Torvergata Extragalactic Group
Faculty:
A.
Cavaliere (alfonso cavaliere at
roma2.infn.it, room D1-34 tel 06-7259-4432)
A. Lapi (andrea.lapi at roma2.infn.it, room D1-13
tel 06-7259-4566)
F.
Vagnetti
(fausto.vagnetti at
roma2.infn.it, room
E0-14
tel 06-7259-4426)
Students:
M. Antonucci (am.antonucci at libero.it)
A.
Paggi (alessandro.paggi at roma2.infn.it, room
EF-002-03-05 tel 06-7259-4867/8)
S.
Turriziani (sara.turriziani at
roma2.infn.it, c/o
ASDC)
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| GROUP
PUBLICATIONS |
CURRENT
RESEARCH TOPICS
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Extragalactic links
RAGNO
3CRR Atlas
NGC / IC Project
The
Blazar Times
Blazars
in the Web
SEDS
Messier Catalog
NED
Related Web Sites
An
Atlas of The Universe
ASP
List of NGC Images
Active
Galaxies Newsletter
SDSS
redshift gallery of quasars
SDSS
redshift gallery of galaxies
Multiwavelength
Atlas of Galaxies
Level
5 Extragalactic Knowledgebase
IPAC
Multiwavelength Messier Museum
IAU
Div. VIII - Galaxies and the Universe
HyperLeda
database for physics of galaxies
Tor
Vergata Astrophysics |
Study
of the X-ray
variability and of the X-ray/Optical
ratio of
serendipitous AGNs from SWIFT and XMM archives. We
extracted two samples of Active Galactic Nuclei (AGN) from the
catalogs of
serendipitous X-ray sources observed by the SWIFT and XMM-Newton
satellites. Ensemble Structure Function variability
analysis in the X-ray
band, on scales from days to few years. Structure Function increasing
as ~time delay^0.1, in agreement with red-noise typical AGN behavior.
Analysis
of the X-ray/Optical ratio for an AGN sample extracted from the
XMM-Newton serendipitous source catalogs (XMMSSC, XMMOMSUSS). Use of simultaneous
X-ray and UV data and study of the effect of variability. Study of the
Disk/Corona relation.
More in: Vagnetti et al 2010, Vagnetti et al 2011.
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Study of variability-selected AGN
samples. Optical
variability
has been used in
the SA57 to select
low luminosity AGNs (LLAGNs) appearing as "variable
galaxies". X-ray survey with XMM-Newton,
catalogue of 140 X-ray sources. Optical
follow-up spectroscopy of variable candidates and of X-ray sources, WHT
and
TNG telescopes. Optical spectroscopy of fainter sources in
progress. Analysis of X-ray spectra in progress. Variable
AGN
candidates can also be
selected in synergic analyses of surveys devoted to the search of
supernovae. Analysis of the data of the STRESS survey, in a
field
overlapping the Chandra Deep Field South (CDFS), produced a
sample of 132
variable AGN candidates. Optical follow-up
spectroscopy of the bright candidates, ESO/NTT telescope. More in: Trevese
et al 2007, Trevese
et al 2008a, Trevese
et al 2008b, Boutsia
et al 2009 |
Galaxy formation and evolution.
We propose a scenario for the joint evolution of galaxies and hosted
supermassive black holes, unifying in a unique evolutionary sequence
Lyman Break Galaxies, Lyman alpha emitters, quasars/active galactic
nuclei, submm bright galaxies and local ellipticals. We propose a
theory to explain, on the basis of strong quasar feedback, the
evolution in size and velocity dispersion of early-type galaxies. We
provide predictions for future observations of high-redshift galaxies
and quasars in different e.m. bands, from IR to UV to submm. More
in: Granato et al 2006, Lapi
et al 2006, Mao et al 2007, Lapi et
al 2008, Fan et al 2008, 2010.
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Galaxy clusters.
We study the thermodynamics of the intracluster medium (ICM). We
develop the ICM Supermodel to accurately describe the radial runs of
the ICM density, entropy, temperature, etc.etc. for both the cool core
and the non cool core cluster classes. We investigate the impact of
energy feedback from supernovae and active galactic nuclei on the ICM.
We provide predictions for future observations of the ICM in X rays and
in the radio/submm bands through the Sunyaev-Zel'dovich effect.
More
in: Lapi et al 2005, Cavaliere et al 2005, Cavaliere & Lapi 2006, Cavaliere & Lapi 2008, Cavaliere et al 2009, Fusco-Femiano et al 2009, Cavaliere et al. 2011. |
Broad Line Region
size
from echo-mapping measures of luminous QSOs. Study
of the relation between luminosity and BLR size for AGNs, and its
extension to high redshift and luminosity. Ongoing campaign of
spectrophotometric
monitoring of 4 luminous (L~10^47 erg
s-1), intermediate redshift (1<z<4) quasars with the Cima
Ekar
1.8 m telescope since 2003. BLR size
determination expected within 2-3 years. Continuum
and emission line
variability detected for the quasar PG 1247+268. Journal of the
observations available on the echoweb
page.
More in: Trevese
et al 2007, 2010 in prep. |
Variability of blazars in the X and gamma rays. We apply to BL Lac Objects the homogeneous single zone Synchrotron
Self-Compton model with log-parabolic electron energy distributions,
and derive relations between spectral variables of the Inverse Compton
radiation in Thomson and Klein-Nishina regimes. We perform ensemble
and individual variability
analysis
of a sample of
gamma-ray sources observed by the EGRET telescope on-board the
Compton-CGRO Observatory in the band 0.1-10 GeV. Study of the Struture
Function for Flat
Spectrum Radio Quasars and for BL Lac Objects. Simulations of gamma-ray
light-curves,
and corresponding Structure Functions, characterized by parametric
choice of durations and amplitudes of the
flares and recurrence times between them. More in: Paggi et al 2009.
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Structure and evolution of disc galaxies.
We propose an empirically motivated theory for the universal
description of the rotation curve out to the virial radius. We study at
a microscopic level the dynamical interactions between baryons and dark
matter during the galaxy formation process. We produce predictions for
the average relationships between the baryonic masses in the form of
gas, stars, supermassive black holes, and the dark matter content of
the host halo. We study the formation and evolution process of disk
galaxies in a cosmological framework through state-of-the-art
analytical and
numerical models. More in: Tonini et al 2006a, 2006b, Shankar et al 2006, Salucci et al 2007a, 2007b, Cook
et al 2009, 2010. |
Dark matter.We
study the cosmological evolution and the macroscopic equilibrium of
dark matter halos. We propose specific models for the dark matter
distribution within cosmic structures. We provide predictions for the
future observations of dark matter through strong and weak
gravitational lensing, and for the annihilation signal in gamma rays
expected from the Galactic Center.
More in: Lapi & Cavaliere 2009a, 2009b, Lapi et al 2010. |