Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of... more Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of stars in the Galaxy and in its satellite system. We here make a forecast of the expected stellar sample resulting from the Dark Energy Survey and the perspectives that it will open for studies of Galactic structure and resolved stellar populations in general. An estimated 1.2 × 10 8 stars will be sampled in DES grizY filters in the southern equatorial hemisphere. This roughly corresponds to 20% of all DES sources. Most of these stars belong to the stellar thick disk and halo of the Galaxy.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2002
Expressions for fundamental spectral line parameters are reported for Gaussian and Lorentzian sha... more Expressions for fundamental spectral line parameters are reported for Gaussian and Lorentzian shape proÿles for homogeneous plasma at equilibrium in presence of the self-absorption. These expressions for Lorentzian proeÿles are applied to the determination of the ratios of transition probabilities and the ratios of optical thicknesses by a new method that we propose in this article. The self-absorption is computed by spectral line proÿles with a Simplex algorithm program ÿtting. Applications to some experimental lines illustrate the appropriate corrections. ?
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation ... more The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Lyα forest, and a radial velocity search for planets around ∼ 8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes five-band imaging of roughly 5200 deg 2 in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg 2 , or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent photometric recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Exploration (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.
The Dark Energy Survey (DES) is a next generation optical imaging survey that will cover 5000 sq.... more The Dark Energy Survey (DES) is a next generation optical imaging survey that will cover 5000 sq. deg. of the southern sky using a new 520 Megapixel CCD camera that will be mounted on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory. The DES will probe dark energy using the 4 complementary techniques of galaxy clusters, weak gravitational lensing, baryon acoustic oscillations, and Type Ia supernovae. In preparation for the survey, we have been carrying out detailed catalog- and image-level simulations of the DES, as part of annual data challenges that use the simulated data to help develop and test our data management pipelines and science analysis codes. Here we will describe our latest round of simulations for DES "Data Challenge 5" (DC5). Our DC5 catalog simulations include: dark matter from a "Carmen" N-body simulation box; a galaxy catalog derived using the "ADDGALS" method; galaxy shapes based on COSMOS data; weak lensing convergence and shear derived from ray tracing, plus stronly-lensed arcs; and stars based the "Trilegal" model of the Milky Way. The simulated galaxy and stellar catalogs are then used to populate simulated DES images, which account for a wide range of instrumental and observational effects due to the telescope and corrector, the CCD detectors, and the atmosphere and weather. Using grid computing resources at Fermilab, some 3.5 TB of simulated DES imaging data have been generated for DC5, covering the 5 DES filters (grizy) over some 200 sq. deg. of sky.
International Journal of Bifurcation and Chaos, 2011
ABSTRACT This paper is devoted to the dynamical behavior of a parametrically driven double-well D... more ABSTRACT This paper is devoted to the dynamical behavior of a parametrically driven double-well Duffing (PDWD) system. Despite the invariant property of symmetry, this simple model exhibits a large diversity of patterns which can be observed in different situations. The transitions between symmetric forms of system responses often lead to bifurcation or crisis and complicated behaviors, such as the coexistence of different kinds of attractors. The bifurcations and crises are discussed, especially those inside the main periodic window. In particular, the role of chaotic saddles and their intrinsic links with the basin of attraction and transient chaos is studied.
Proceedings of The International Astronomical Union, 2004
We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire... more We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties, than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing sign of advanced merger condition, when compared to a control sample.
Proceedings of The International Astronomical Union, 2004
We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire... more We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing signs of advanced merger condition, when compared to a control sample.
In this paper we present an automatic followup method of changing objects of topology in a sequen... more In this paper we present an automatic followup method of changing objects of topology in a sequence of images. The method we propose is based on an algorithm of image segmentation with deformable active contour and an algorithm of objects localization. The segmentation algorithm is based on a new modeling of the image using the geometrical active contour model. This modeling allows a bidirectional evolution of contour and limit the constraints of initialization. The formulation by level set method of the active contour model allows an automatic management of the changes of topology. We have then used this segmentation algorithm to develop an objects localization algorithm using a local dynamic prediction of displacements.
In this paper we present a new algorithm to track an organ in a sequence of medical images in ord... more In this paper we present a new algorithm to track an organ in a sequence of medical images in order to achieve a 3D reconstruction. The automatic method that we propose allows the tracking of the external contour of the anatomical organ in all the sequence from one contour initialized by the user on the first image. The required operations for our tracking method are the region-based active contours segmentation. The objects localization with dynamic prediction of displacements is based on the level-set functions and the definition of the region of interest for the robust local estimation of the image model. An application of this method is the 3D reconstruction of abdominal aorta.
Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of... more Wide angle and deep surveys, regardless of their primary purpose, always sample a large number of stars in the Galaxy and in its satellite system. We here make a forecast of the expected stellar sample resulting from the Dark Energy Survey and the perspectives that it will open for studies of Galactic structure and resolved stellar populations in general. An estimated 1.2 × 10 8 stars will be sampled in DES grizY filters in the southern equatorial hemisphere. This roughly corresponds to 20% of all DES sources. Most of these stars belong to the stellar thick disk and halo of the Galaxy.
Journal of Quantitative Spectroscopy and Radiative Transfer, 2002
Expressions for fundamental spectral line parameters are reported for Gaussian and Lorentzian sha... more Expressions for fundamental spectral line parameters are reported for Gaussian and Lorentzian shape proÿles for homogeneous plasma at equilibrium in presence of the self-absorption. These expressions for Lorentzian proeÿles are applied to the determination of the ratios of transition probabilities and the ratios of optical thicknesses by a new method that we propose in this article. The self-absorption is computed by spectral line proÿles with a Simplex algorithm program ÿtting. Applications to some experimental lines illustrate the appropriate corrections. ?
The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation ... more The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Lyα forest, and a radial velocity search for planets around ∼ 8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes five-band imaging of roughly 5200 deg 2 in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg 2 , or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent photometric recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Exploration (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.
The Dark Energy Survey (DES) is a next generation optical imaging survey that will cover 5000 sq.... more The Dark Energy Survey (DES) is a next generation optical imaging survey that will cover 5000 sq. deg. of the southern sky using a new 520 Megapixel CCD camera that will be mounted on the 4m Blanco telescope at the Cerro Tololo Inter-American Observatory. The DES will probe dark energy using the 4 complementary techniques of galaxy clusters, weak gravitational lensing, baryon acoustic oscillations, and Type Ia supernovae. In preparation for the survey, we have been carrying out detailed catalog- and image-level simulations of the DES, as part of annual data challenges that use the simulated data to help develop and test our data management pipelines and science analysis codes. Here we will describe our latest round of simulations for DES "Data Challenge 5" (DC5). Our DC5 catalog simulations include: dark matter from a "Carmen" N-body simulation box; a galaxy catalog derived using the "ADDGALS" method; galaxy shapes based on COSMOS data; weak lensing convergence and shear derived from ray tracing, plus stronly-lensed arcs; and stars based the "Trilegal" model of the Milky Way. The simulated galaxy and stellar catalogs are then used to populate simulated DES images, which account for a wide range of instrumental and observational effects due to the telescope and corrector, the CCD detectors, and the atmosphere and weather. Using grid computing resources at Fermilab, some 3.5 TB of simulated DES imaging data have been generated for DC5, covering the 5 DES filters (grizy) over some 200 sq. deg. of sky.
International Journal of Bifurcation and Chaos, 2011
ABSTRACT This paper is devoted to the dynamical behavior of a parametrically driven double-well D... more ABSTRACT This paper is devoted to the dynamical behavior of a parametrically driven double-well Duffing (PDWD) system. Despite the invariant property of symmetry, this simple model exhibits a large diversity of patterns which can be observed in different situations. The transitions between symmetric forms of system responses often lead to bifurcation or crisis and complicated behaviors, such as the coexistence of different kinds of attractors. The bifurcations and crises are discussed, especially those inside the main periodic window. In particular, the role of chaotic saddles and their intrinsic links with the basin of attraction and transient chaos is studied.
Proceedings of The International Astronomical Union, 2004
We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire... more We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties, than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing sign of advanced merger condition, when compared to a control sample.
Proceedings of The International Astronomical Union, 2004
We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire... more We identify 175 Seyfert galaxies from the Southern Sky Redshift Survey - SSRS2. We use the entire SSRS2 catalog to investigate the correlation between the presence of AGN with host environment. The AGN phenomenon is more strongly correlated with the internal host properties than with the external environment. In particular, we find that Seyferts reside in more luminous galaxies, and are twice as frequent in barred galaxies and systems showing signs of advanced merger condition, when compared to a control sample.
In this paper we present an automatic followup method of changing objects of topology in a sequen... more In this paper we present an automatic followup method of changing objects of topology in a sequence of images. The method we propose is based on an algorithm of image segmentation with deformable active contour and an algorithm of objects localization. The segmentation algorithm is based on a new modeling of the image using the geometrical active contour model. This modeling allows a bidirectional evolution of contour and limit the constraints of initialization. The formulation by level set method of the active contour model allows an automatic management of the changes of topology. We have then used this segmentation algorithm to develop an objects localization algorithm using a local dynamic prediction of displacements.
In this paper we present a new algorithm to track an organ in a sequence of medical images in ord... more In this paper we present a new algorithm to track an organ in a sequence of medical images in order to achieve a 3D reconstruction. The automatic method that we propose allows the tracking of the external contour of the anatomical organ in all the sequence from one contour initialized by the user on the first image. The required operations for our tracking method are the region-based active contours segmentation. The objects localization with dynamic prediction of displacements is based on the level-set functions and the definition of the region of interest for the robust local estimation of the image model. An application of this method is the 3D reconstruction of abdominal aorta.
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Papers by Bruno Rossetto