Cold and Warm Gas Outflows in Radio AGN

The study of the conditions and the kinematics of the gas in the central region of AGN provides important information on the relevance of feedback effects connected to the nuclear activity. Quantifying these effects is key for constraining galaxy evolution models. Here we present a short summary of our recent efforts to study the occurrence and the impact of gas outflows in radio-loud AGN that are in their first phase of their evolution. Clear evidence for AGN-induced outflows have been found for the majority of these young radio sources. The outflows are detected both in (warm) ionized as well in (cold) atomic neutral gas and they are likely to be driven (at least in most of the cases) by the interaction between the expanding jet and the medium. The mass outflow rates of the cold gas (HI) appear to be systematically higher than those of the ionized gas. The former reach up to ~50 Msun/yr, and are in the same range as "mild" starburst-driven superwinds in ULIRGs, whilst the latter are currently estimated to be a few solar masses per year. However, the kinetic powers associated with these gaseous outflow are a relatively small fraction (a few x 10^-4) of the Eddington luminosity of the galaxy. Thus, they do not appear to match the requirements of the galaxy evolution feedback models.Comment: Invited talk, to appear in the Proceedings of the IAU Symposium 267, "Co-Evolution of Central Black Holes and Galaxies", B.M. Peterson, R.S. Somerville, T. Storchi-Bergmann, eds., in pres

Is There a Compelling Argument for Ontic Structural Realism?

Structural realism first emerged as an epistemological thesis aimed to avoid the so-called pessimistic meta-induction on the history of science. Some authors, however, suggested that the preservation of structure across theory-change is best explained by endorsing the metaphysical thesis that structure is all there is. While the possibility of this latter, „ontic‟ form of structural realism has been extensively debated, though, not much has been said concerning its justification. In this paper, I distinguish between two arguments in favour of ontic structural realism that can be reconstructed from the literature, and find both of them wanting

The interplay between radio-activity and the ISM in radio galaxies

Radio-loud AGNs can inhabit regions with a very rich ISM. The presence of this rich medium is likely related to the origin and evolution of the host galaxy and of the active nucleus. Recent observations show that a large fraction of radio galaxies contains a significant young stellar population. This supports the idea that mergers are responsible for both the starburst phase and the triggering of the nuclear activity. The gas that reaches the central regions can have quite disturbed kinematics, likely due to the effects of the AGN activity and in particular of the powerful radio jets. The recent detection of fast nuclear gas outflows, observed both in ionised and neutral gas, is giving new and important insights into the physical conditions of the gaseous medium around the nucleus and the interaction between the AGN and this medium. Finally, as another example of the interplay between the radio activity and the ISM, the possibility of star formation induced by the passage of the radio jet will be discussed.Comment: Invited paper to appear in the proceedings of IAU Symposium 222, The Interplay among Black Holes, Stars and ISM in Galactic Nuclei; Storchi Bergmann et al. eds. 6 pages, 3 figure

Archaeology of active galaxies across the electromagnetic spectrum

Analytical and numerical galaxy-formation models indicate that active galactic nuclei (AGNs) likely play a prominent role in the formation and evolution of galaxies. However, quantifying this effect requires knowledge of how the nuclear activity proceeds throughout the life of a galaxy, whether it alternates with periods of quiescence and, if so, on what timescales these cycles occur. This topic has attracted growing interest, but making progress remains a challenging task. For optical and radio AGNs, a variety of techniques are used to perform a kind of "archaeology" that traces the signatures of past nuclear activity. Here we summarize recent findings regarding the lifecycle of an AGN from optical and radio observations. The limited picture we have so far suggests that these cycles can range from long periods of 10^7-10^8 yr to shorter periods of 10^4-10^5 yr, even reaching extreme events on timescales of just a few years. Together with simulations, observational results regarding the multiple cycles of AGN activity help to create a complete picture of the AGN lifecycle.Comment: Invited Review for Nature Astronomy, Aug 28 issue. 10 pages, 8 figure

The Many Routes to AGN Feedback

The energy released by Active Galactic Nuclei (AGN) in the form of radiation, winds, or radio plasma jets, is known to impact on the surrounding interstellar medium. The result of these processes, known as AGN (negative) feedback, is suggested to prevent gas, in and around galaxies, from cooling, and to remove, or at least redistribute, gas by driving massive and fast outflows, hence playing a key role in galaxy evolution. Given its importance, a large effort is devoted by the astronomical community to trace the effects of AGN on the surrounding gaseous medium and to quantify their impact for different types of AGN. This review briefly summarizes some of the recent observational results obtained in different wavebands, tracing different phases of the gas. I also summarize the new insights they have brought, and the constraints they provide to numerical simulations of galaxy formation and evolution. The recent addition of deep observations of cold gas and, in particular, of cold molecular gas, has brought some interesting surprises and has expanded our understanding of AGN and AGN feedback.Comment: Invited review at the conference "Quasars at all cosmic epochs", published in Frontiers in Astronomy and Space Sciences, open access (https://doi.org/10.3389/fspas.2017.00042), 17 pages, 4 figure

Seismic and solar performance of historical city. Urban form-based multicriteria analysis

The understanding of the global performance of a historical city is a complex balance of several specific issues and requires a multi-disciplinary approach to face with actual urban phenomena and challenges, such as the seismic risk and energy efficiency, that are strongly influenced by urban form. This paper focuses on the potential of urban metrics and typological indicators for describing the seismic vulnerability and the solar radiation availability of distinct urban textures, and the correlation between the two aspects. Comparative analysis at fabric scale was conducted on the historical centre of Rieti (Latium, Italy), to underline the main seismic and solar indicators. In the last decade, we witnessed the spreading of urban scale assessment and analysis tools, but seldom using an integrated approach to face the complexity of the historical city. Relying on morpho-typological indicators, the proposed method characterizes the fabrics in terms of seismic vulnerability and solar availability through a multicriteria analysis. The analysis reveals substantial differences between fabrics using three groups of indicators: Plan, Space and Analysis-oriented. Each group describes different features of the urban fabrics that affect seismic and solar performance and suggests improvement strategies. The purpose is to support policymaker and designer in the urban renovation process

Can Reasons Be Propositions? Against Dancy's Attack on Propositionalism

The topic of this article is the ontology of practical reasons. We draw a critical comparison between two views. According to the first, practical reasons are states of affairs; according to the second, they are propositions. We first isolate and spell out in detail certain objections to the second view that can be found only in embryonic form in the literature – in particular, in the work of Jonathan Dancy. Next, we sketch possible ways in which one might respond to each one of these objections. A careful evaluation of these complaints and responses, we argue, shows that the first view is not as obviously compelling as it is thought by Dancy. Indeed, it turns out that the view that practical reasons are propositions is by no means unworkable and in fact, at least under certain assumptions, explicit considerations can be made in favour of a propositional construal of reasons

Chitin and lignin. Natural ingredients from waste materials to make innovative and healthy products for humans and plant

In a globalized world, plants are continually cut to obtain free land for intensive farming without remembering their important function in the planet ecosystem. They produce oxygen eliminating the carbon dioxide excess, contributing to reduce the pollution thus giving a great support to our health. According to the World Health Organization (WHO), air pollution -both outdoor and indoor- is nowadays "the biggest environmental risk to health carrying responsibility for about one in every nine deaths" (WHO, 2016). Outdoor pollution alone, in fact, kills around 3 million people each year. At this purpose however, it is necessary to remember that indoor emission of nanoparticles (NP) represent 50-80% of human exposure, calculated from 10.000 to 249.000 NP/mL air-while in polluted air NP are from ~10.000 to 50.000 NP/mL (Nohynek, 2011). Thus, there is a strict necessity "to consider air pollution as a global health priority in the sustainable development agenda" (WHO, 2016). Moreover, plants, multicellular organisms, as well as humans have evolved several mechanisms of defense and sensor systems to detect danger and prevent entry of most foreign material (Janeway et al, 2001). The sensors can direct and assist the host defenses by the use of specialized cells that ingest and digest foreign material. This protective non-specific method is called innate immune system, also connected with certain specific molecular patterns recognition associated with invading microbes or tissue damage (Nurnberger et al., 2004). In addition to innate immunity, vertebrates have evolved an adaptive immune system that relies on many antigen receptors, expressed by specialized immune cells. Unlike vertebrates, plants lack mobile defender cells and respond to infection by a two-branched immune system (Jones et al., 2006). The first branch recognizes and responds to all the common microbial molecules, while the second responds to pathogen virulence factors only. However, both plants and mammals have as first-line defense a barrier that, separating and shielding the interior of the body from the surrounding environment, represents the initial obstacle to be overcame from any pathogenic microorganisms. This barrier not only provides a physical separation, but releases also substances with antimicrobial properties. Moreover, when the first-line barrier has been breached, sensor systems are activated to give information to other components of the host defenses. Thus, while mammals activate, for example, the toll-like receptors capable to recognize families of compounds unique to microbes, plants release specialized compounds known as elicitors, signaling molecules able to induce their defense systems (Trouvelot et al., 2014). Examples of common ingredients, used from both plant and mammal as elicitors and defense-related compounds, are chitin and lignin. In this work, these materials will be briefly reviewed and results of chitin nanofibrils production and usage is reported. Finally, possible usage of combined chitin-lignin nanofibrils in commercial products will be pointed out