4,356 research outputs found

    Natural Polymers and Cosmeceuticals for a Healthy and Circular Life: The Examples of Chitin, Chitosan, and Lignin

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    The present review considers the design and introduction of new cosmeceuticals in the market, based on natural polymers and active molecules extracted from biomass, in a biomimetic strategy, starting with a consideration of the biochemical mechanisms, followed by natural precision biopolymer production. After introducing the contest of nanobiotechnology in relationship with its applicability for skin contact products and classifying the currently available sustainable polymers, some widely selected abundant biopolymers (chitin, chitosan, and lignin), showing specific functionalities (anti-microbial, anti-oxidant, anti-inflammatory, etc.), are described, especially considering the possibility to combine them in nanostructured tissues, powders, and coatings for producing new cosmeceuticals, but with potentialities in other sectors, such as biomedical, personal care, and packaging sectors. After observing the general increase in market wellness and beauty forecasts over the next few years, parallelisms between nano and macro scales have suggested that nanobiotechnology application expresses the necessity to follow a better way of producing, selecting, and consuming goods that will help to transform the actual linear economy in a circular economy, based on redesigning, reducing, recycling, and reusing

    The jet-ISM interaction in the Outer Filament of Centaurus A

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    The interaction between the radio plasma ejected by the active nucleus of a galaxy and the surrounding medium is a key process that can have a strong impact on the interstellar medium of the galaxy and hence on galaxy evolution. The closest laboratory where we can observe and investigate this phenomenon is the radio galaxy Centaurus A. About 15 kpc north-east of this galaxy, a particularly complex region is found: the so-called Outer Filament where jet-cloud interactions have been proposed to occur. We investigate the presence of signatures of jet-ISM interaction by a detailed study of the kinematics of the ionized gas, expanding on previous results obtained from the HI. We observed two regions of the outer filament with VLT/VIMOS in the IFU observing mode. Emission from Hbeta and [OIII]4959,5007\AA\ is detected in both pointings. We found two distinct kinematical components of ionized gas that well match the kinematics of the nearby HI cloud. One component follows the regular kinematics of the rotating gas while the second shows similar velocities to those of the nearby HI component thought to be disturbed by an interaction with the radio jet. We suggest that the ionized and atomic gas are part of the same dynamical gas structure originating as result of the merger that shaped Centaurus A and which is regularly rotating around Centaurus A as proposed by other authors. The gas (ionized and HI) with anomalous velocities is tracing the interaction of the Large-Scale radio Jet with the ISM, suggesting that, although poorly collimated as structure, the jet is still active. However, we can exclude that a strong shock is driving the ionization of the gas. It is likely that a combination of jet entrainment and photoionization by the UV continuum from the central engine is needed in order to explain both the ionization and the kinematics of the gas in the Outer Filament.Comment: 6 pages, 6 figures, 1 table. Final version accepted for publication on A&

    The impact of the warm outflow in the young (GPS) radio source & ULIRG PKS 1345+12 (4C 12.50)

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    (Abridged) We present new deep VLT/FORS optical spectra with intermediate resolution and large wavelength coverage of the GPS radio source and ULIRG PKS1345+12 (4C12.50; z=0.122), taken with the aim of investigating the impact of the nuclear activity on the circumnuclear ISM. PKS1345+12 is a powerful quasar and is also the best studied case of an emission line outflow in a ULIRG. Using the density sensitive transauroral emission lines [S II]4068,4076 and [O II]7318,7319,7330,7331, we pilot a new technique to accurately model the electron density for cases in which it is not possible to use the traditional diagnostic [S II]6716/6731, namely sources with highly broadened complex emission line profiles and/or high (Ne > 10^4 cm^-3) electron densities. We measure electron densities of Ne=2.94x10^3 cm^-3, Ne=1.47x10^4 cm^-3 and Ne=3.16x10^5 cm^-3 for the regions emitting the narrow, broad and very broad components respectively. We calculate a total mass outflow rate of 8 M_sun yr^-1. We estimate the total mass in the warm gas outflow is 8x10^5 M_sun. The total kinetic power in the warm outflow is 3.4x10^42 erg s^-1. We find that only a small fraction (0.13% of Lbol) of the available accretion power is driving the warm outflow, significantly less than currently required by the majority of quasar feedback models (~5-10\% of Lbol), but similar to recent findings by Hopkins et al. (2010) for a two-stage feedback model. The models also predict that AGN outflows will eventually remove the gas from the bulge of the host galaxy. The visible warm outflow in PKS1345+12 is not currently capable of doing so. However, it is entirely possible that much of the outflow is either obscured by a dense and dusty natal cocoon and/or in cooler or hotter phases of the ISM. This result is important not just for studies of young (GPS/CSS) radio sources, but for AGN in general.Comment: Accepted for publication in MNRAS. 11 pages, 4 figure

    Fast Outflows of Neutral Hydrogen in Radio Galaxies

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    AGN activity is known to drive fast outflows of gas. We report the discovery of fast outflows of neutral gas with velocities over 1000 km/s in a number of radio galaxies. In the best studied object, 3C~293, the kinematical properties of the neutral and ionised outflows are similar, indicating a common origin. Moreover, the outflow appears to be located near the radio lobes and not near the nucleus. This suggests that the interaction between the radio jet and the ISM is driving the outflow.Comment: To appear in the proceedings of IAU Symposium 222,"The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", eds Storchi-Bergmann et al; 2 pages, 1 figur

    The fast molecular outflow in the Seyfert galaxy IC5063 as seen by ALMA

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    We use high-resolution (0.5 arcsec) CO(2-1) observations performed with ALMA to trace the kinematics of the molecular gas in the Seyfert 2 galaxy IC5063. A fast outflow of molecular gas extends along the entire radio jet, with the highest outflow velocities about 0.5kpc from the nucleus, at the location of the brighter hot-spot in the W lobe. The data show that a massive, fast outflow with velocities up to 650 km/s of cold molecular gas is present, in addition to one detected earlier in warm H2, HI and ionised gas. Both the central AGN and the radio jet could energetically drive the outflow. However, the characteristics of the outflowing gas point to the radio jet being the main driver. This is important, because IC5063, although one of the most powerful Seyfert galaxies, is a relatively weak radio source (P = 3x10^23 W/Hz). All the observed characteristics can be described by a scenario of a radio plasma jet expanding into a clumpy medium, interacting directly with the clouds and inflating a cocoon that drives a lateral outflow into the interstellar medium. This model is consistent with results obtained by recent simulations such as those of Wagner et al.. A stronger, direct interaction between the jet and a gas cloud is present at the location of the brighter W lobe. Even assuming the most conservative values for the conversion factor CO-to-H2, the mass of the outflowing gas is between 1.9 and 4.8x10^7 Msun. These amounts are much larger than those of the outflow of warm gas (molecular and ionized) and somewhat larger than of the HI outflow. This suggests that most of the observed cold molecular outflow is due to fast cooling after being shocked. This gas is the end product of the cooling process. Our CO observations demonstrate that fast outflows of molecular gas can be driven by relativistic jets.Comment: Accepted for publication in A&A. 11 pages, 8 figure

    Gas outflows in radio galaxies

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    We present a summary of our recent results on gas outflows in radio galaxies. Fast outflows (up to 2000 km/s) have been detected both in ionized and neutral gas. The latter is particularly surprising as it shows that, despite the extremely energetic phenomena occurring near an AGN, some of the outflowing gas remains, or becomes again, neutral. These results are giving new and important insights on the physical conditions of the gaseous medium around an AGN.Comment: To appear in the proceedings of the IAU Symposium #217, Recycling Intergalactic and Interstellar Matter, eds. P.-A. Duc, J. Braine, and E. Brinks, 6 pages. The full paper with high resolution images can be downloaded from http://www.astron.nl/~morganti/Papers/outflows.ps.g

    The outer filament of Centaurus A as seen by MUSE

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    We investigate signatures of a jet-interstellar medium (ISM) interaction using optical integral-field observations of the so-called outer filament near Centaurus A, expanding on previous results obtained on a more limited area. Using the Multi Unit Spectroscopic Explorer (MUSE) on the VLT during science verification, we observed a significant fraction of the brighter emitting gas across the outer filament. The ionized gas shows complex morphology with compact blobs, arc-like structures and diffuse emission. Based on the kinematics, we identified three main components. The more collimated component is oriented along the direction of the radio jet. The other two components exhibit diffuse morphology together with arc-like structures also oriented along the radio jet direction. Furthermore, the ionization level of the gas is found to decrease from the more collimated component to the more diffuse components. The morphology and velocities of the more collimated component confirm our earlier results that the outer filament and the nearby HI cloud are likely partially shaped by the lateral expansion of the jet. The arc-like structures embedded within the two remaining components are the clearest evidence of a smooth jet-ISM interaction along the jet direction. This suggests that, although poorly collimated, the radio jet is still active and has an impact on the surrounding gas. This result indicates that the effect on the ISM of even low-power radio jets should be considered when studying the influence Active Galactic Nuclei can have on their host galaxy.Comment: 5 pages, 3 figures, Accepted for publication by A&

    The location of the broad HI absorption in 3C305: clear evidence for a jet-accelerated neutral outflow

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    We present high-spatial resolution 21-cm HI VLA observations of the radio galaxy 3C305 (z=0.041). These new high-resolution data show that the ~1000 km/s broad HI absorption, earlier detected in low-resolution WSRT observations, is occurring against the bright, eastern radio lobe, about 1.6 kpc from the nucleus. We use new optical spectra taken with the WHT to make a detailed comparison of the kinematics of the neutral hydrogen with that of the ionised gas. The striking similarity between the complex kinematics of the two gas phases suggests that both the ionised gas and the neutral gas are part of the same outflow. Earlier studies of the ionised gas had already found evidence for a strong interaction between the radio jet and the interstellar medium at the location of the eastern radio lobe. Our results show that the fast outflow produced by this interaction also contains a component of neutral atomic hydrogen. The most likely interpretation is that the radio jet ionises the ISM and accelerates it to the high outflow velocities observed. Our observations demonstrate that, following this strong jet-cloud interaction, not all gas clouds are destroyed and that part of the gas can cool and become neutral. The mass outflow rate measured in 3C~305 is comparable, although at the lower end of the distribution, to that found in Ultra-Luminous IR galaxies. This suggests that AGN-driven outflows, and in particular jet-driven outflows, can have a similar impact on the evolution of a galaxy as starburst-driven superwinds.Comment: Accepted for publication in A&A. 7 pages, 4 figure

    Large-scale HI in nearby radio galaxies: segregation in neutral gas content with radio source size

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    We present results of a study of neutral hydrogen (HI) in a complete sample of nearby non-cluster radio galaxies. We find that radio galaxies with large amounts of extended HI (M_HI >= 10^9 M_solar) all have a compact radio source. The host galaxies of the more extended radio sources, all of Fanaroff & Riley type-I, do not contain these amounts of HI. We discuss several possible explanations for this segregation. The large-scale HI is mainly distributed in disk- and ring-like structures with sizes up to 190 kpc and masses up to 2 x 10^10 M_solar. The formation of these structures could be related to past merger events, although in some cases it may also be consistent with a cold-accretion scenario.Comment: 4 pages, 2 figures. Accepted for publication in A&A Letters. A version with full resolution figures can be found at http://www.astro.rug.nl/~emonts/emonts_HIletter_jan07.pd
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