The nature of extremely red galaxies in the local universe

We investigate the nature of extremely red galaxies (ERGs), objects whose colours are redder than those found in the red sequence present in colour–magnitude diagrams of galaxies. We selected from the Sloan Digital Sky Survey Data Release 7 a volume-limited sample of such galaxies in the redshift interval 0.010 < z < 0.030, brighter than Mr = −17.8 (magnitudes dereddened, corrected for the Milky Way extinction) and with (g − r) colours larger than those of galaxies in the red sequence. This sample contains 416 ERGs, which were classified visually. Our classification was cross-checked with other classifications available in the literature. We found from our visual classification that the majority of objects in our sample are edge-on spirals (73 per cent). Other spirals correspond to 13 per cent, whereas elliptical galaxies comprise only 11 per cent of the objects. After comparing the morphological mix and the distributions of Hα/Hβ and axial ratios of ERGs and objects in the red sequence, we suggest that dust, more than stellar population effects, is the driver of the red colours found in these extremely red galaxies.

Testing phenomenological and theoretical models of dark matter density profiles with galaxy clusters

We use the stacked gravitational lensingmass profile of four high-mass (M 1015M ) galaxy clusters around z≈0.3 from Umetsu et al. to fit density profiles of phenomenological [Navarro– Frenk–White (NFW), Einasto, S´ersic, Stadel, Baltz–Marshall–Oguri (BMO) and Hernquist] and theoretical (non-singular Isothermal Sphere, DARKexp and Kang & He) models of the dark matter distribution. We account for large-scale structure effects, including a two-halo term in the analysis.We find that the BMO model provides the best fit to the data as measured by the reduced χ2. It is followed by the Stadel profile, the generalized NFW profile with a free inner slope and by the Einasto profile. The NFW model provides the best fit if we neglect the two-halo term, in agreement with results from Umetsu et al. Among the theoretical profiles, the DARKexp model with a single form parameter has the best performance, very close to that of the BMO profile. This may indicate a connection between this theoretical model and the phenomenology of dark matter haloes, shedding light on the dynamical basis of empirical profiles which emerge from numerical simulations.

Galaxy triplets in Sloan Digital Sky Survey Data Release 7: II. A connection with compact groups?

We analyse a sample of 71 triplets of luminous galaxies derived from the work of O’Mill et al. We compare the properties of triplets and their members with those of control samples of compact groups, the 10 brightest members of rich clusters and galaxies in pairs. The triplets are restricted to have members with spectroscopic redshifts in the range 0.01 ≤ z ≤ 0.14 and absolute r-band luminosities brighter than Mr = −20.5. For these member galaxies, we analyse the stellar mass content, the star formation rates, the Dn(4000) parameter and (Mg − Mr) colour index. Since galaxies in triplets may finally merge in a single system, we analyse different global properties of these systems. We calculate the probability that the properties of galaxies in triplets are strongly correlated. We also study total star formation activity and global colours, and define the triplet compactness as a measure of the percentage of the system total area that is filled by the light of member galaxies. We concentrate in the comparison of our results with those of compact groups to assess how the triplets are a natural extension of these compact systems. Our analysis suggests that triplet galaxy members behave similarly to compact group members and galaxies in rich clusters. We also find that systems comprising three blue, star-forming, young stellar population galaxies (blue triplets) are most probably real systems and not a chance configuration of interloping galaxies. The same holds for triplets composed of three red, non-star-forming galaxies, showing the correlation of galaxy properties in these systems. From the analysis of the triplet as a whole, we conclude that, at a given total stellar mass content, triplets show a total star formation activity and global colours similar to compact groups. However, blue triplets show a high total star formation activity with a lower stellar mass content. From an analysis of the compactness parameter of the systems we find that light is even more concentrated in triplets than in compact groups. We propose that triplets composed of three luminous galaxies, should not be considered as an analogous of galaxy pairs with a third extra member, but rather they are a natural extension of compact groups.

The formation of AlF by radiative association

The formation of the aluminium monofluoride molecule AlF by radiative association of the Al and F atoms is estimated. The radiative association of Al(2P) and F(2P) atoms is found to be dominated by the approach along theA1 potential energy curve accompanied by spontaneous emission into theX1 + ground state of the AlF. For temperatures ranging from 300 to 14 000 K, the rate coefficients are found to vary from 1.35×10−17 to 9.31×10−16 cm3 s−1, respectively.These values indicate that only a small amount of AlF molecules can be formed by radiative association in the inner envelope of carbon-rich stars and other hostile environments.

3C 273 variability at 7 mm: evidence of shocks and precession in the jet

We report on four years of observations of 3C 273 at 7mm obtained with the Itapetinga radio telescope, in Brazil, between 2009 and 2013. We detected a flare in 2010 March, when the flux density increased by 50 per cent and reached 35 Jy. After the flare, the flux density started to decrease and reached values lower than 10 Jy. We suggest that the 7-mm flare is the radio counterpart of the γ -ray flare observed by the Fermi Large Area Telescope in 2009 September, in which the flux density at high energies reached a factor of 50 of its average value. A delay of 170 d between the radio and γ -ray flares was revealed using the discrete correlation function (DCF) that can be interpreted in the context of a shock model, in which each flare corresponds to the formation of a compact superluminal component that expands and becomes optically thin at radio frequencies at latter epochs. The differences in flare intensity between frequencies and at different times are explained as a consequence of an increase in the Doppler factor δ, as predicted by the 16-yr precession model proposed by Abraham & Romero. This increase has a large effect on boosting at high frequencies while it does not affect the observed optically thick radio emission too much. We discuss other observable effects of the variation in δ, such as the increase in the formation rate of superluminal components, the variations in the time delay between flares and the periodic behaviour of the radio light curve that we have found to be compatible with changes in the Doppler factor.

A Galactic ring of minimum stellar density near the solar orbit radius

We analyse the secular effects of a long-lived Galactic spiral structure on the stellar orbits with mean radii close to the corotation resonance. By test-particle simulations and different spiral potential models with parameters constrained on observations, we verified the formation of a minimum with amplitude ∼30–40 per cent of the background disc stellar density at corotation. Such a minimum is formed by the secular angular momentum transfer between stars and the spiral density wave on both sides of corotation. We demonstrate that the secular loss (gain) of angular momentum and decrease (increase) of mean orbital radius of stars just inside (outside) corotation can counterbalance the opposite trend of exchange of angular momentum shown by stars orbiting the librational points L4/5 at the corotation circle. Such secular processes actually allow steady spiral waves to promote radial migration across corotation. We propose some pieces of observational evidence for the minimum stellar density in the Galactic disc, such as its direct relation to the minimum in the observed rotation curve of the Galaxy at the radius r ∼ 9 kpc (for R0 = 7.5 kpc), as well as its association with a minimum in the distribution of Galactic radii of a sample of open clusters older than 1Gyr. The closeness of the solar orbit adius to the corotation resonance implies that the solar orbit lies inside a ring of minimum surface density (stellar + gas). This also implies a correction to larger values for the estimated total mass of the Galactic disc, and consequently, a greater contribution of the disc componente to the inner rotation curve of the Galaxy.

Gestione del copyright nel tool autore AContent.

Con l’avvento di Internet, potentissimo strumento tecnologico di diffusione di informazioni e di comunicazione a distanza, anche le modalità di apprendimento sono cambiate: persino nelle scuole si tende a non utilizzare più i classici libri di testo, ma ad utilizzare dispositivi dai quali scaricare in formato elettronico, libri, dispense, test, video ed ogni altro genere di materiale di apprendimento, dando vita a un vero e proprio nuovo modo di apprendere chiamato E-learning, più veloce, comodo e ricco di alternative rispetto al vecchio modello offline che si presentava sottoforma di floppy inizialmente e poi di CD-ROM. E-learning significa, electronic based learning, ed è appunto una vera e propria metodologia di didattica che sfrutta e viene facilitata da risorse e servizi disponibili e accessibili virtualmente in rete. Al momento vi sono numerose piattaforme di E-learning, una delle quali è il nucleo di questa tesi, ovvero il tool autore AContent. Questo documento di tesi, infatti, raccoglie la descrizione della progettazione e della fase implementativa della gestione delle politiche di copyright per il tool AContent. L’obbiettivo è quello di rendere possibile l’assegnazione di un copyright a qualsiasi tipo di materiale didattico venga creato, caricato e/o condiviso sulla piattaforma in questione. Pertanto l’idea è stata quella di dare la possibilità di scegliere fra più copyright preimpostati, utilizzando degli standard di licenze riguardanti i diritti d’autore, lasciando anche l’opportunità di inserire la propria politica.

Why Cherry-Picking Never Leads to Harmonisation: The Case of the Limitations on Copyright under Directive 2001/29/EC

The article examines whether the norms laid down in the Directive in relation to the exceptions and limitations on copyright and related rights can be conducive to a sensible degree of harmonisation across the European Union. Before discussing the degree of harmonisation achieved so far by the Directive, the first part gives a short overview of the main characteristics of the list of exceptions and limitations contained in Article 5 of the Directive. A comprehensive review of the implementation of each limitation by the Member States is beyond the scope of this article. The following section takes a closer look at three examples of limitations that have led to legislative changes at the Member State level as express measures towards the implementation of the Information Society Directive, that is, the limitations for the benefit of libraries, for teaching and research, and for persons with a disability. These exceptions and limitations were later on also identified by the European Commission as key elements in the deployment of a digital knowledge economy. The analysis will show that the implementation of the provisions on limitations in the Information Society Directive did not, and probably cannot, yield the expected level of harmonisation across the European Union and that, as a consequence, there still exists a significant degree of uncertainty for the stakeholders regarding the extent of permissible acts with respect to copyright protected works.

Limitations: The Centerpiece of Copyright in Distress

After the exclusive rights in copyright have been consolidated in a century-long historical development, limitations and exceptions have become the main instrument to determine the exact scope of copyright. Limitations and exceptions do not merely fine-tune copyright protection. Rather, they balance the interests of authors, rightholders, competitors and end-users in a quadrupolar copyright system. Understanding this is of particular importance in the digital and networked information society, where copyrighted information is not only created and consumed, but constantly extracted, regrouped, repackaged, recombined, abstracted and interpreted. However, serious doubts exist whether the present, historically grown system of limitations adequately balances the interests involved in the information society. Both the closed list of limitations allowed under Art. 5 of the EU Information Society Directive 2001/29/EC and a narrowly interpreted three-step test contained in Arts. 13 TRIPS and 5 (5) of the Information Society Directive appear as obstacles in the way of achieving the appropriate balance needed. This brief article outlines the issues involved which were discussed at the International Conference on “Commons, Users, Service Providers – Internet (Self-) Regulation and Copyright” which took place in Hannover, Germany, on 17/18 March 2010 on the occasion of the launch of JIPITEC.

Unsticking the centre-piece – the liberation of European copyright law?

Following European legislative initiatives in the field of copyright limitations and exceptions, policy flexibilities formerly available to mem- ber states has been greatly diminished. The law in this area is increasingly incapable of accommodating any expansion in the scope of freely permitted acts, even where such expansion may be an appropriate response to changes in social and technological conditions. In this article, the causes of this problem are briefly canvassed and a number of potential solutions are noted. It is suggested that one such solution – the adoption of an open, factor-based model similar to s 107 of the United States’ Copyright Act – has not received the serious attention it deserves. The fair use paradigm has generally been dismissed as excessively unpredictable, contrary to international law and/or culturally alien. Drawing on recent fair use scholarship, it is argued here that these disadvantages are over-stated and that the potential for the development of a European fair use model merits investigation.

Richtungsweisend oder eine nur begrenzt wahrgenommene Chance? Der Copyright-Code des Wittem-Projekts

Der „European copyright code“ des Wittem-Projekts von 4/2010 ist pragmatisch, konstruktiv-konservativ ausgefallen. Traditionell das Werk- und Autorenverständnis. Schrankenregelungen werden über einen hybriden Ansatz offen gehalten. Bildung und Wissenschaft werden nicht gerade verwöhnt. Die Wittem-Gruppe hat sich nicht in den „Treibsand visionärer Modelle“ begeben wollen. Ein guter Text, aber dann doch nicht wirklich wegweisend für den Umgang mit Wissen und Information in elektronischen Räumen, am ehesten noch durch den Vorschlag einer Schrankenbestimmung zur Begünstigung des wirtschaftlichen Wettbewerbs.

The Law Applicable to Online Copyright Infringements int ALI and CLIP Proposals: A Rebalance of Interest Needed?

The article discusses the problems of applicable law to copyright infringements online. It firstly identifies the main problems related to the well established territoriality principle and the lex loci protectionis rules. Then; the discussion focuses on the "ubiquitous infringement" rule recently proposed by the American Law Institute (ALI) and the European Max Planck Group for Conflicts of Law and Intellectual Propoperty (CLIP). The author strongly welcomes a compromise between the territoriality and universality approaches suggested in respect of ubiquitous infringement cases. At the same time; the paper draws the attention that the interests of "good faith" online service providers (such as legal certainty and foreseeability) have been until now underestimated and invites to take these interests into account when merging the projects into a common international proposal.