Astrophysics

Astrophysics Journal Club History
Date	Room	Speaker	Title
Jul 24 2013 14:00	Library Red Meeting Room	Sandra Raimundo (SISSA)	Orbital decay of black hole pairs
ABSTRACT: Massive black hole pairs in clumpy, self-gravitating circumnuclear disks: stochastic orbital decay http://arxiv.org/abs/1307.0822
Jul 10 2013 14:00	Room 135	Ambra Nanni and Sandra Raimundo (SISSA)	The Star Formation Law and the Polar AGN IR emission
ABSTRACT: The Origin of Physical Variations in the Universal Star Formation Law http://arxiv.org/abs/1307.1467 Dust in the polar region as a major contributor to the IR emission of AGN http://arxiv.org/abs/1306.4312
Jun 26 2013 14:00	Library Red Meeting Room	Gianluca Castignani (SISSA)	Estimating redshift distributions with spatial correlations
ABSTRACT: Estimating redshift distributions with spatial correlations: method and application to data http://adsabs.harvard.edu/abs/2013arXiv1303.4722M Recovering redshift distributions with cross-correlations: pushing the boundaries http://adsabs.harvard.edu/abs/2013MNRAS.431.3307S
Jun 13 2013 14:00	Library Blue Meeting Room	Heng Hao and Juan Manuel Loaiza (SISSA)	A high-z dust obscured galaxy; AGN outflows
ABSTRACT: A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34 http://arxiv.org/abs/1304.4256 AGN outflows trigger starbursts in gas-rich galaxies http://arxiv.org/abs/1306.0684
May 29 2013 14:00	Library Red Meeting Room	Yang Chen and Sandra Raimundo (SISSA)	Dust in nearby galaxies; Cataclysmic variables
ABSTRACT: Mapping dust through emission and absorption in nearby galaxies http://arxiv.org/abs/1305.2923 An accurate geometric distance to the compact binary SS Cygni vindicates accretion disc theory http://arxiv.org/abs/1305.5846
May 17 2013 14:00	Library Red Meeting Room	Juan Manuel Loaiza (SISSA)	Supermassive Black Hole Formation via Direct Collapse
ABSTRACT: Supermassive Black Hole Formation at High Redshifts via Direct Collapse: Physical Processes in the Early Stage http://arxiv.org/abs/1304.1369
May 02 2013 15:30	Library Blue Meeting Room	Rossella Aversa (SISSA)	Black Hole scaling relations
ABSTRACT: The strong environmental dependence of black hole scaling relations http://adsabs.harvard.edu/abs/2013arXiv1302.6237M
Apr 19 2013 14:00	Library Red Meeting Room	Ranieri Baldi and Sandra Raimundo (SISSA)	Local radio AGN and Seyfert/Quiescent galaxies comparison
ABSTRACT: The relation between morphology, accretion modes and environmental factors in local radio AGN http://adsabs.harvard.edu/abs/2013MNRAS.430.3086G Fueling AGN-I: How the Global Characteristics of the Central Kiloparsec of Seyferts differ from Quiescent Galaxies http://arxiv.org/abs/1303.4399
Apr 03 2013 14:30	Library Red Meeting Room	Zhenyi Cai (SISSA)	Simulations of black hole and galaxy growth
ABSTRACT: Black Hole-Galaxy Correlations without Self-Regulation http://arxiv.org/abs/1303.5058
Mar 20 2013 14:30	Library Red Meeting Room	Ambra Nanni and Juan Manuel Loaiza (SISSA)	Dust in the early Universe and Obese Black Holes
ABSTRACT: The Origin of Dust in the Early Universe: Probing the Star Formation History of Galaxies by their Dust Content http://arxiv.org/abs/1011.1303 Unravelling obese black holes in the first galaxies http://arxiv.org/abs/1302.6996
Mar 06 2013 14:30	Library Red Meeting Room	Sandra Raimundo (SISSA)	A recoiling black hole?
ABSTRACT: A Captured Runaway Black Hole in NGC 1277? http://adsabs.harvard.edu/abs/2013arXiv1302.4458S
Feb 20 2013 14:30	Library Red Meeting Room	Heng Hao and Ranieri Baldi (SISSA)	AGN - Infrared, X-ray and Radio properties
ABSTRACT: Infrared and X-ray selection of AGN http://arxiv.org/abs/1302.2920 Star formation and dust in radio galaxies http://adsabs.harvard.edu/abs/2013MNRAS.429.2407H
Feb 06 2013 14:30	Library Red Meeting Room	Gianluca Castignani (SISSA)	Black Hole mass measurements
ABSTRACT: Measuring the black hole mass in quasars: http://adsabs.harvard.edu/abs/2012MNRAS.427.3081T
Jan 22 2013 14:30	Library Red Meeting Room	Eolo di Casola and Sandra Raimundo (SISSA)	Cosmology and an Ultramassive Black Hole
ABSTRACT: An expanding Universe without Dark Matter and Dark Energy: http://arxiv.org/abs/1212.1110 X-ray emission from NGC 1277: an ultramassive black hole http://adsabs.harvard.edu/abs/2013arXiv1301.1800F
Jan 10 2013 14:00	Library Red Meeting Room	Yang Chen (SISSA)	A grand design spiral
ABSTRACT: High velocity dispersion in a rare grand-design spiral galaxy at redshift z = 2.18 http://www.nature.com/nature/journal/v487/n7407/full/nature11256.html
Dec 04 2012 14:00	Library Red Meeting Room	Juan Manuel Loaiza and Sandra Raimundo (SISSA)	Black Hole spin and mass
ABSTRACT: Black hole spin evolution: http://adsabs.harvard.edu/abs/2012arXiv1211.4871D An over-massive black hole: http://adsabs.harvard.edu/abs/2012Natur.491..729V
Nov 21 2012 14:00	Big Meeting Room	Sandra Raimundo, Juan Manuel Loaiza, Ambra Nanni (SISSA)	AGN feedback, star formation and a z=11 galaxy
ABSTRACT: Summary of the conference: Nuclei of Seyfert galaxies and QSOs - Central engine & conditions of star formation. The star formation rate of X-ray selected AGN: http://adsabs.harvard.edu/abs/2012A%26A...545A..45R. Simulations of black hole feedback: http://adsabs.harvard.edu/abs/2010MNRAS.402..789N. NASA press release on z = 11 galaxy candidate: http://adsabs.harvard.edu/abs/2012arXiv1211.3663C.
Nov 06 2012 14:00	Library Red Meeting Room	Rossella Aversa (SISSA)
ABSTRACT:
Oct 23 2012 14:00	Library Red Meeting Room	Ranieri Baldi and Sandra Raimundo (SISSA)	Radio Galaxies and Compton-thick AGN
ABSTRACT: Low luminosity radio galaxies:\r\n\r\nhttp://adsabs.harvard.edu/abs/2012arXiv1210.4540B.\r\n\r\nCompton-thick AGN from the X-ray background:\r\n\r\nhttp://adsabs.harvard.edu/abs/2012A%26A...546A..98A.
Oct 09 2012 14:00	Library Red Meeting Room	Zhenyi Cai and Sandra Raimundo (SISSA)	Measuring the size of an accretion disc
ABSTRACT: Accretion disc sizes in gravitationally lensed quasars:\r\n\r\nhttp://adsabs.harvard.edu/abs/2008A%26A...490..933E.\r\n\r\nAccretion disc size and black hole mass relation:\r\n\r\nhttp://adsabs.harvard.edu/abs/2008A%26A...490..933E.
Sep 25 2012 14:00	Library Red Meeting Room	Ambra Nanni (SISSA)	Detection of dark galaxies
ABSTRACT: Detection of dark galaxies and circum-galactic filaments fluorescently illuminated by a quasar at z = 2.4: http://adsabs.harvard.edu/abs/2012MNRAS.425.1992C.
Sep 11 2012 14:00	Library Red Meeting Room	Heng Hao and Alessandro Bressan (SISSA)	Spectral energy distributions
ABSTRACT: Discussion of SED fitting in AGN and galaxies and stellar evolution modelling.
Jul 04 2012 14:00	Library Red Meeting Room	Sandra Raimundo (SISSA)	Black hole fuelling in obscured quasars
ABSTRACT: Heavily Obscured Quasar Host Galaxies at z~2 are Disks, Not Major Mergers: http://arxiv.org/abs/1206.4063
Jun 19 2012 14:00	Library Red Meeting Room	Sandra Raimundo (SISSA)	Gas and stellar dynamics in NGC 1068
ABSTRACT: 2D mapping of young stars in the inner 180 pc of NGC 1068: correlation with molecular gas ring and stellar kinematics: http://arxiv.org/abs/1206.4014.
Jun 05 2012 14:00	Library Red Meeting Room	Sandra Raimundo and Yang Chen (SISSA)	Outflows and Stellar Initial Mass Function
ABSTRACT: Strong quasar feedback in the early Universe:\r\n\r\nhttp://arxiv.org/abs/1204.2904.\r\n\r\nThe Stellar Initial Mass Function in Early-Type Galaxies:\r\n\r\nhttp://arxiv.org/abs/1205.6471.
May 22 2012 14:00	Big Meeting Room	Gianluca Castignani and Paolo Salucci (SISSA)	High redshift galaxy cluster and dark matter
ABSTRACT: A z = 1.75 galaxy cluster:\r\n\r\nhttp://arxiv.org/abs/1205.3786\r\nhttp://arxiv.org/abs/1205.3787\r\nhttp://arxiv.org/abs/1205.3788\r\n\r\nOn the local dark matter density:\r\n\r\nhttp://arxiv.org/abs/1205.4033.
May 08 2012 14:00	Library Red Meeting Room	Yang Chen and Luigi Danese (SISSA)	A young galaxy and luminosity functions
ABSTRACT: A highly magnified candidate for a young galaxy seen when the Universe was 500 Myrs old:\r\n\r\nhttp://arxiv.org/abs/1204.2305\r\n\r\nDiscussion of luminosity functions and AGN/star formation detected in the X-rays and Infrared
Apr 10 2012 14:00	Big Meeting Room	Sandra Raimundo (SISSA)	AGN evolution
ABSTRACT: A Tale of Two Populations: The Contribution of Merger and Secular Processes to the Evolution of Active Galactic Nuclei:\r\n\r\nhttp://arxiv.org/abs/1203.5117.
Dec 06 2011 14:00	room 135	Nicola Bassan (SISSA)	Cooling of superfluid neutron stars
ABSTRACT: I will discuss three papers* reporting (and discussing) a rapid surface cooling of the Cassiopeia A Neutron Star. The Cas A supernova remnant was discovered by Chandra in 1999 and since then has been well studied. We know that the neutron star is young (330 yr.) and close-by (3.4 kpc). Remarkably Heinke and Ho claim that the surface temperature has dropped by 4% in just 10 years (with 5.4 sigma significance) and this fast cooling is now interpreted as the best available indication for the existence of a superfluid in neutron stars interior. * Heinke and Ho, Astrophys.J.719:L167-L171,2010 - arXiv 1007.4719 * Shternin et al, Mon. Not. Roy. Astron. Soc. 412, L108-L112 (2011) - arXiv 1012.0045 * Page et al, PRL.106:081101,2011 - arXiv 1011.6142
Apr 07 2011 14:00	SISSA, Room 135	Maryam Tavakoli (SISSA)	Diffuse Galactic Gamma Rays at intermediate and high latitudes
ABSTRACT:
Mar 31 2011 14:00	SISSA, Room 135	Riccardo Valdarnini (SISSA)	Turbulence and numerical viscosity in SPH simulations of galaxy clusters
ABSTRACT: A large set of N-body/SPH hydrodynamical cluster simulations is constructed with the aim of studying in SPH simulations the impact of numerical viscosity and the development of turbulence in the ICM of the simulated clusters. The SPH code implements a time-dependent artificial viscosity scheme in which each particle has its own viscosity parameter, whose time evolution is governed by the local shock conditions. The spectral properties of the gas velocity field are investigated at the present epoch by measuring for the simulated clusters the velocity power spectrum E(k). The longitudinal component E_c(k) exhibits over a limited range a Kolgomorov-like scaling k^-5/3, whilst the solenoidal power spectrum component E_s(k) is strongly influenced by numerical resolution effects. Dissipative effects are found to be significant at length scales 100-300 Kpc, with viscous damping of the velocities being less pronounced in those runs with the lowest artificial viscosity. The turbulent energy density radial profile E_turb(r) is strongly affected by the numerical viscosity scheme adopted in the simulations, with the turbulent-to-total energy density ratios being higher in the runs with the lowest artificial viscosity settings and lying in the range between a few percent and ~10%. These values are in accord with the corresponding ratios extracted from previous cluster simulations realized using mesh-based codes. Finally, radiative runs are characterized by the presence in the cluster inner regions of high levels of turbulence, generated by the interaction of the compact cool gas core with the ambient medium.
Mar 24 2011 14:00	SISSA, Room 135	Wolfgang Kastaun (SISSA)	Overview of gravitational waves from isolated neutron stars
ABSTRACT:
Feb 24 2011 14:00	SISSA, Room 135	Rudy Gilmore (SISSA)	Detection of GeV emission from GRBs with Cherenkov telescopes
ABSTRACT:
Jan 20 2011 14:00	SISSA, Room 128	Joaquin Gonzalez-Nuevo (SISSA)	Discussion of the Planck early results
ABSTRACT:
Jan 13 2011 13:30	SISSA, Room 128	Jorge Moreno (SISSA)	Discussion of Callegari et al 2010: "Growing Massive Black Hole Pairs in Minor Mergers of Disk Galaxies
ABSTRACT: http://arxiv.org/abs/1002.1712
Dec 17 2010 14:00	SISSA, room 128	Ilias Cholis (SISSA)	The Fermi haze as a signal of Dark Matter
ABSTRACT: Recent full-sky maps of the Galaxy from the Fermi Gamma-Ray Space Telescope have revealed a diffuse component of emission towards the Galatic centerand extending up to ~50 degrees in latitude. This Fermi 'haze' is the inverse Compton emission generated by the same electrons which generate the microwave synchrotron haze at WMAP wavelengths. The gamma-ray haze has two distinct characteristics: the spectrum is significantly harder than emission elsewhere in the Galaxy and the morphology is elongated in latitude with respect to longitude with an axis ratio of ~1.7. If these electrons are generated through annihilations of dark matter particles in the Galactic halo, this morphology is difficult to realize with a standard spherical halo and isotropic cosmic-ray diffusion. However, I will discuss the possibility that anisotropic diffusion along ordered field lines towards the center of the Galaxy coupled with a prolate dark matter halo can easily yield the required morphology without making unrealistic assumptions about diffusion parameters. Furthermore, a Sommerfeld enhancement to the annihilation cross-section of ~100 yields a good fit to the morphology, amplitude, and spectrum of both the gamma-ray and microwave haze, while explaining the local CR anomalies as well.
Dec 15 2010 13:15	SISSA, room 135	Joaquin Gonzalez-Nuevo (SISSA)	Discussion of Negrello et al 2010: "The Detection of a Population of Submillimeter-Bright, Strongly Lensed Galaxies"
ABSTRACT:
Dec 10 2010 14:00	SISSA, room 128	Nicola Bassan (SISSA)	Discussion of Demorest et al. 2010: "A two-solar-mass neutron star measured using Shapiro delay"
ABSTRACT: See http://www.nature.com/nature/journal/v467/n7319/full/nature09466.html
Mar 31 2010 13:10	SISSA, Room E	Rudy Gilmore (SISSA)	The Extragalactic Background Light and Gamma-ray Attenuation
ABSTRACT: Attenuation of high-energy gamma-rays by pair-production with UV, optical and IR background photons provides a link between the history of galaxy formation and high-energy astrophysics. I will present results from recent semi-analytic models, which are based upon a Lambda-CDM hierarchical structure formation scenario and employ all ingredients thought to be important to galaxy formation and evolution, including reprocessing of starlight by dust to mid- and far-IR wavelengths. These models are successful in reproducing a large variety of observational constraints such as number counts, luminosity and mass functions, and color bi-modality. A closely related undertaking has been to extend these calculations to far-UV wavelengths by accounting for the quasar contribution and processing by the intergalactic medium. These wavelengths are relevant for absorption of the lower energy GeV photons that are being seen by the recently-launched Fermi Gamma-Ray Space Telescope satellite. I will show how background photons affect the observations of high-energy blazars, and also discuss how observations of the highest energy emission from gamma-ray bursts (GRBs) by satellite and ground-based detectors could be a useful, though technically challenging, probe this evolving photon population. Local absorption of the GRB photons within the host galaxy could also affect this emission, and I will show some preliminary results of an attempt to estimate the magnitude of this effect.
Mar 17 2010 13:00	SISSA, Room E	Valeria Pettorino (SISSA)	Coupled dark energy cosmologies and impact on structure formation
ABSTRACT: I will give an overview of coupled dark energy models, in which dark energy interacts with other species in the universe. I will illustrate the effects that coupled dark energy has at the linear and non-linear level, introducing an effective force, stronger than gravity and mediated by dark energy, that modifies structure formation. In particular I will describe the case of growing neutrino quintessence, where dark energy properties are connected to the neutrino mass, predicting the possibility of having stable neutrino lumps at supercluster scales.
Mar 10 2010 13:00	Room E	Eunwha Jeong (SISSA)	Topological defects and cosmic strings: a brief summary
ABSTRACT: We will briefly review the origin of topological defects, and their impact on cosmology and high energy physics. We also discuss cosmic strings, which are the only type of defects that may have left physically observable signals.
Feb 24 2010 13:00	SISSA, Room E	Jason Dick (SISSA)	Large-scale inhomogeneities may improve the cosmic concordance of supernovae
ABSTRACT: http://arxiv.org/abs/1002.1232
Apr 22 2009 14:30	SISSA, Room E	Stefano Finazzi (SISSA)	Analogue Models of Gravity and Superluminal Travel
ABSTRACT: He motivation for studying analogue models of gravity is twofold. Firstly, phenomena as Hawking radiation are very faint in ordinary gravity. The realization of analogue systems as Bose-Einstein condensates can be the only way to probe experimentally some prediction of quantum field theory in curved spacetimes. Secondly, analogue models suggest different theoretical approaches to quantum gravity phenomenology. Furthermore, as a by-product, the instruments developed to study these systems can be used to solve open problems of general relativity and quantum field theory. As an example, I will show this machinery at work to put constraints on the possibility of superluminal travel through the Alcubierre's warp drive.
Feb 25 2009 14:30	SISSA, Room E	Carlo Baccigalupi (SISSA)	"What the small angle CMB really tells us about the curvature of the Universe" Authors: Clifton et al.
ABSTRACT: ArXiv:0902.1313