Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae

We have developed a systematic procedure to study the disks in Algol-type binaries using spectroscopic analysis, synthetic spectra, and tomography. We analyzed 119 H-alpha spectra of TT Hya, an Algol-type eclipsing interacting binary, collected from 1985-2001. The new radial velocities enabled us to derive reliable orbital elements, including a small non-zero eccentricity, and to improve the accuracy of the absolute dimensions of the system. High resolution IUE spectra were also analyzed to study the formation of the ultraviolet lines and continuum. Synthetic spectra of the iron curtain using our new shellspec program enabled us to derive a characteristic disk temperature of 7000K. We have demonstrated that the UV emission lines seen during total primary eclipse cannot originate from the accretion disk, but most likely arise from a hotter disk-stream interaction region. The synthetic spectra of the stars, disk, and stream allowed us to derive a lower limit to the mass transfer rate of 2e-10 solar masses per year. Doppler tomography of the observed H-alpha profiles revealed a distinct accretion disk. The difference spectra produced by subtracting the synthetic spectra of the stars resulted in an image of the disk, which virtually disappeared once the composite synthetic spectra of the stars and disk were used to calculate the difference spectra. An intensity enhancement of the resulting tomogram revealed images of the gas stream and an emission arc. We successfully modeled the gas stream using shellspec and associated the emission arc with an asymmetry in the accretion disk.Comment: 46 pages, 15 figures, 6 tables, accepted by Ap

Absolute properties of BG Ind - a bright F3 system just leaving the Main Sequence

We present photometric and spectroscopic analysis of the bright detached eclipsing binary BG Ind. The masses of the components are found to be 1.428 +- 0.008 and 1.293 +- 0.008 Msun and the radii to be 2.290+-0.017 and 1.680+-0.038 Rsun for primary and secondary stars, respectively. Spectra- and isochrone-fitting coupled with color indices calibration yield [Fe/H]=-0.2+-0.1. At an age of 2.65+-0.20 Gyr BG Ind is well advanced in the main-sequence evolutionary phase - in fact, its primary is at TAMS or just beyond it. Together with three similar systems (BK Peg, BW Aqr and GX Gem) it offers an interesting opportunity to test the theoretical description of overshooting in the critical mass range 1.2-1.5 Msun.Comment: 8 pages, 5 figures, corrected bugs in author lis

METRO - The role and future perspectives of Cohesion Policy in the planning of Metropolitan Areas and Cities. Annex I: Conceptual framework and methodology

The scope of the ESPON METRO project is rather broad, as its research positions at the intersection of a number of fields, ranging from territorial governance and spatial planning, to public administration and policy analysis and European integration studies, up to regional development studies. In order to explore the role that metropolitan areas play as catalysts and drivers of global development, as a consequence of complex processes of socioeconomic reorganisation and rescaling that have evolved through time, and with particular reference to the European Union (EU) cohesion policy, the METRO research team has framed its action and analysis within a composite and articulated conceptual and methodological framework. In particular, the latter has been shaped in order to allow the researchers engaged in the project to answer the three main policy questions animating the study: PQ1 | What role do metropolitan areas play in the development, management and implementation of the cohesion policy? PQ2 | What is the added value of the cohesion policy in the planning and implementation of metropolitan policies? PQ3 | What role does the cohesion policy play in consolidating metropolitan governance and cooperation? The conceptual and methodological framework for the project has been developed during the first months of the research, building on the materials already included in the project proposal, that were further detailed and consolidated through: A thorough consideration of previous research works on similar matters as well as of the existing scientific literature in the field of metropolitan governance and European integration and Europeanisation. The interaction with the project’s Steering Committee Members during the METRO kick-off meeting (October the 9th, 2020), the comments received in response to the Delivery n.1 and the outcomes of the Steering Committee Meeting n. 2 (November the 16th, 2020) and 3 (February the 23rd, 2021). This Annex to the Final Report presents said conceptual framework and methodology more in detail

Generalization of Weierstrassian Elliptic Functions to Rn{\bf R}^{n}

The Weierstrassian $\wp, \zeta$ and $\sigma$ functions are generalized to ${\bf R}^{n}$. The $n=3$ and $n=4$ cases have already been used in gravitational and Yang-Mills instanton solutions which may be interpreted as explicit realizations of spacetime foam and the monopole condensate, respectively. The new functions satisfy higher dimensional versions of the periodicity properties and Legendre's relations obeyed by their familiar complex counterparts. For $n=4$, the construction reproduces functions found earlier by Fueter using quaternionic methods. Integrating over lattice points along all directions but two, one recovers the original Weierstrassian elliptic functions.Comment: pp. 9, Late

Spurious Eccentricities of Distorted Binary Components

I discuss the effect of physical distortion on the velocities of close binary components and how we may use the resulting distortion of velocity curves to constrain some properties of binary systems, such as inclination and mass ratio. Precise new velocities for 5 Cet convincingly detect these distortions with their theoretically predicted phase dependence. We can even use such distortions of velocity curves to test Lucy's theory of convective gravity darkening. The observed distortions for TT Hya and 5 Cet require the contact components of those systems to be gravity darkened, probably somewhat more than predicted by Lucy's theory but clearly not as much as expected for a radiative star. These results imply there is no credible evidence for eccentric orbits in binaries with contact components. I also present some speculative analyses of the observed properties of a binary encased in a non-rotating common envelope, if such an object could actually exist, and discuss how the limb darkening of some recently calculated model atmospheres for giant stars may bias my resuts for velocity-curve distortions, as well as other results from a wide range of analyses of binary stars.Comment: 14 pp, 2 tables, 12 fig; under review by Ap

METRO - The role and future perspectives of Cohesion Policy in the planning of Metropolitan Areas and Cities. Annex II: The role of Metropolitan areas within the EU cohesion policy

This Annex to the final Report presents and discusses in a comparative manner the evidence collected in the nine case studies that have been explored in the framework of the ESPON Targeted Analysis METRO – The role and future perspectives of cohesion policy in the planning of Metropolitan Areas and Cities (Annexes III to XI). More in detail, the document synthesizes and compares the information collected by the various research teams through the application of the project’s analytical protocol and as a consequence of their continuous interaction with the respective stakeholders. The report is organised following the three main policy questions that have been driving the analysis: PQ1 | What role do metropolitan areas and cities play in the development, management and implementation of the European Union (EU) cohesion policy? PQ2 | What is the added value of the EU cohesion policy in the planning and implementation of metropolitan policies? PQ3 | What role does the EU cohesion policy play in consolidating metropolitan governance and cooperation? These questions are answered through the comparative analysis and assessment of the territorial and institutional contexts in which the nine stakeholders involved in the projects are active: Metropolitan City of Turin (CMTo), Barcelona Metropolitan Area (AMB), Lisbon Metropolitan Area (LMA), Brno Metropolitan Area (BMA), Metropolitan Area of Gdańsk-Gdynia-Sopot (MAG), Metropolitan City of Florence (CMFi), Métropole de Lyon (MdL), Brussels-Capital Region (BCR), Riga Metropolitan Area (RMA)

TYC 2675-663-1: A newly discovered W UMa system in an active state

The recently discovered eclipsing binary system TYC 2675-663-1 is a X-ray source, and shows properties in the optical that are similar to the W UMa systems, but are somewhat unusual compared to what is seen in other contact binary systems. The goal of this work is to characterize its properties and investigate its nature by means of detailed photometric and spectroscopic observations. We have performed extensive V-band photometric measurements with the INTEGRAL satellite along with ground-based multi-band photometric observations, as well as high-resolution spectroscopic monitoring from which we have measured the radial velocities of the components. These data have been analysed to determine the stellar properties, including the absolute masses and radii. Additional low-resolution spectroscopy was obtained to investigate spectral features. From the measured eclipse timings we determine an orbital period for the binary of P=0.4223576+-0.0000009 days. The light-curve and spectroscopic analyses reveal the observations to be well represented by a model of an overcontact system composed of main-sequence F5 and G7 stars (temperature difference of nearly 1000 K), with the possible presence of a third star. Low-resolution optical spectroscopy reveals a complex H alpha emission, and other features that are not yet understood. The unusually large mass ratio of q=0.81+-0.05 places it in the rare "H" (high mass ratio) subclass of the W UMa systems, which are presumably on their way to coalescence.Comment: 12 pages in double column format. Accepted for publication in Astronomy and Astrophysic

ADAR1 Facilitates HIV-1 Replication in Primary CD4+ T Cells.

Unlike resting CD4+ T cells, activated CD4+T cells are highly susceptible to infection of human immunodeficiency virus 1 (HIV-1). HIV-1 infects T cells and macrophages without activating the nucleic acid sensors and the anti-viral type I interferon response. Adenosine deaminase acting on RNA 1 (ADAR1) is an RNA editing enzyme that displays antiviral activity against several RNA viruses. Mutations in ADAR1 cause the autoimmune disorder Aicardi-Goutieères syndrome (AGS). This disease is characterized by an inappropriate activation of the interferon-stimulated gene response. Here we show that HIV-1 replication, in ADAR1-deficient CD4+T lymphocytes from AGS patients, is blocked at the level of protein translation. Furthermore, viral protein synthesis block is accompanied by an activation of interferon-stimulated genes. RNA silencing of ADAR1 in Jurkat cells also inhibited HIV-1 protein synthesis. Our data support that HIV-1 requires ADAR1 for efficient replication in human CD4+T cells