281 research outputs found
CO excitation in the Seyfert galaxy NGC7130
We present a coherent multi-band modelling of the CO Spectral Energy
Distribution of the local Seyfert Galaxy NGC7130 to assess the impact of the
AGN activity on the molecular gas. We take advantage of all the available data
from X-ray to the sub-mm, including ALMA data. The high-resolution (~0.2") ALMA
CO(6-5) data constrain the spatial extension of the CO emission down to ~70 pc
scale. From the analysis of the archival CHANDRA and NuSTAR data, we infer the
presence of a buried, Compton-thick AGN of moderate luminosity, L_2-10keV ~
1.6x10^{43} ergs-1. We explore photodissociation and X-ray-dominated regions
(PDRs and XDRs) models to reproduce the CO emission. We find that PDRs can
reproduce the CO lines up to J~6, however, the higher rotational ladder
requires the presence of a separate source of excitation. We consider X-ray
heating by the AGN as a source of excitation, and find that it can reproduce
the observed CO Spectral Energy Distribution. By adopting a composite PDR+XDR
model, we derive molecular cloud properties. Our study clearly indicates the
capabilities offered by current-generation of instruments to shed light on the
properties of nearby galaxies adopting state-of-the art physical modelling.Comment: 5 pages, 3 figures, accepted for publication in MNRAS Letter
CO excitation in the Seyfert galaxy NGC 34: stars, shock or AGN driven?
We present a detailed analysis of the X-ray and molecular gas emission in the
nearby galaxy NGC 34, to constrain the properties of molecular gas, and assess
whether, and to what extent, the radiation produced by the accretion onto the
central black hole affects the CO line emission. We analyse the CO Spectral
Line Energy Distribution (SLED) as resulting mainly from Herschel and ALMA
data, along with X-ray data from NuSTAR and XMM-Newton. The X-ray data analysis
suggests the presence of a heavily obscured AGN with an intrinsic luminosity of
L erg s. ALMA high
resolution data () allows us to scan the nuclear region
down to a spatial scale of pc for the CO(6-5) transition. We
model the observed SLED using Photo-Dissociation Region (PDR), X-ray-Dominated
Region (XDR), and shock models, finding that a combination of a PDR and an XDR
provides the best fit to the observations. The PDR component, characterized by
gas density and temperature K,
reproduces the low-J CO line luminosities. The XDR is instead characterised by
a denser and warmer gas (, K), and is
necessary to fit the high-J transitions. The addition of a third component to
account for the presence of shocks has been also tested but does not improve
the fit of the CO SLED. We conclude that the AGN contribution is significant in
heating the molecular gas in NGC 34.Comment: Accepted for publication in MNRAS. 10 pages, 6 figure
CO excitation in the Seyfert galaxy NGC 7130
We present a coherent multiband modelling of the carbon monoxide (CO) spectral energy distribution of the local Seyfert galaxy NGC 7130 to assess the impact of the active galactic nucleus (AGN) activity on the molecular gas. We take advantage of all the available data from X-ray to the submillimetre, including ALMA data. The high-resolution (~0.2 arcsec) ALMA CO(6-5) data constrain the spatial extension of the CO emission down to an ~70 pc scale. From the analysis of the archival Chandra and NuSTAR data, we infer the presence of a buried, Compton-thick AGN of moderate luminosity, L2-10 keV ~1.6 × 1043 erg s-1. We explore photodissociation and X-ray-dominated-region (PDR and XDR) models to reproduce the CO emission. We find that PDRs can reproduce the CO lines up to J ~ 6; however, the higher rotational ladder requires the presence of a separate source of excitation. We consider X-ray heating by the AGNs as a source of excitation, and find that it can reproduce the observed CO spectral energy distribution. By adopting a composite PDR+XDR model, we derivemolecular cloud properties. Our study clearly indicates the capabilities offered by the current generation of instruments to shed light on the properties of nearby galaxies by adopting state-of-the-art physical modelling
AGN impact on the molecular gas in galactic centres as probed by CO lines
We present a detailed analysis of the X-ray, infrared, and carbon monoxide (CO) emission for a sample of 35 local (z ≤ 0.15), active (LX ≥ 1042 erg s-1) galaxies. Our goal is to infer the contribution of far-ultraviolet (FUV) radiation from star formation (SF), and X-ray radiation from the active galactic nuclei (AGNs), respectively, producing photodissociation regions (PDRs) and X-ray-dominated regions (XDRs), to the molecular gas heating. To this aim, we exploit the CO spectral line energy distribution (CO SLED) as traced by Herschel, complemented with data from single-dish telescopes for the low-J lines, and high-resolution ALMA images of the mid-J CO emitting region. By comparing our results to the Schmidt-Kennicutt relation, we find no evidence for AGN influence on the cold and low-density gas on kpc-scales. On nuclear (r = 250 pc) scales, we find weak correlations between the CO line ratios and either the FUV or X-ray fluxes: this may indicate that neither SF nor AGN radiation dominates the gas excitation, at least at r = 250 pc. From a comparison of the CO line ratios with PDR and XDR models, we find that PDRs can reproduce observations only in presence of extremely high gas densities (n > 105 cm-3). In the XDR case, instead, the models suggest moderate densities (n ≈ 102-4 cm-3). We conclude that a mix of the two mechanisms (PDR for the mid-J, XDR, or possibly shocks for the high-J) is necessary to explain the observed CO excitation in active galaxies
CO excitation in the Seyfert galaxy NGC 34: Stars, shock or AGN driven?
We present a detailed analysis of the X-ray and molecular gas emission in the nearby galaxy NGC 34, to constrain the properties of molecular gas, and assess whether, and to what extent, the radiation produced by the accretion on to the central black hole affects the CO line emission. We analyse the CO spectral line energy distribution (SLED) as resulting mainly from Herschel and ALMA data, along with X-ray data from NuSTAR and XMM-Newton. The X-ray data analysis suggests the presence of a heavily obscured active galactic nucleus (AGN) with an intrinsic luminosity of L1-100 keV ≃ 4.0 × 1042 erg s-1. ALMA high-resolution data (θ ≃ 0.2 arcsec) allow us to scan the nuclear region down to a spatial scale of ≈100 pc for the CO(6-5) transition. We model the observed SLED using photodissociation region (PDR), X-ray-dominated region (XDR), and shock models, finding that a combination of a PDR and an XDR provides the best fit to the observations. The PDR component, characterized by gas density log(n/cm-3) = 2.5 and temperature T = 30 K, reproduces the low-J CO line luminosities. The XDR is instead characterized by a denser and warmer gas (log(n/cm-3) = 4.5, T = 65 K), and is necessary to fit the high-J transitions. The addition of a third component to account for the presence of shocks has been also tested but does not improve the fit of the CO SLED. We conclude that the AGN contribution is significant in heating the molecular gas in NGC 34
Cyclic RGD peptidomimetics containing bifunctional diketopiperazine scaffolds as new potent integrin ligands
The synthesis of eight bifunctional diketopiperazine (DKP) scaffolds is described; these were formally derived from 2,3-diaminopropionic acid and aspartic acid (DKP-1-DKP-7) or glutamic acid (DKP-8) and feature an amine and a carboxylic acid functional group. The scaffolds differ in the configuration at the two stereocenters and the substitution at the diketopiperazinic nitrogen atoms. The bifunctional diketopiperazines were introduced into eight cyclic peptidomimetics containing the Arg-Gly-Asp (RGD) sequence. The resulting RGD peptidomimetics were screened for their ability to inhibit biotinylated vitronectin binding to the purified integrins \u3b1 v\u3b2 3 and \u3b1 v\u3b2 5, which are involved in tumor angiogenesis. Nanomolar IC 50 values were obtained for the RGD peptidomimetics derived from trans DKP scaffolds (DKP-2-DKP-8). Conformational studies of the cyclic RGD peptidomimetics by 1H NMR spectroscopy experiments (VT-NMR and NOESY spectroscopy) in aqueous solution and Monte Carlo/Stochastic Dynamics (MC/SD) simulations revealed that the highest affinity ligands display well-defined preferred conformations featuring intramolecular hydrogen-bonded turn motifs and an extended arrangement of the RGD sequence [C\u3b2(Arg)-C\u3b2(Asp) average distance 658.8 \uc5]. Docking studies were performed, starting from the representative conformations obtained from the MC/SD simulations and taking as a reference model the crystal structure of the extracellular segment of integrin \u3b1 v\u3b2 3 complexed with the cyclic pentapeptide, Cilengitide. The highest affinity ligands produced top-ranked poses conserving all the important interactions of the X-ray complex. Copyright \ua9 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
GASP XXIV. The history of abruptly quenched galaxies in clusters
The study of cluster post starburst galaxies gives useful insights on the
physical processes quenching the star formation in the most massive
environments. Exploiting the MUSE data of the GAs Stripping Phenomena in
galaxies (GASP) project, we characterise the quenching history of 8 local
cluster galaxies that were selected for not showing emission lines in their
fiber spectra. We inspect the integrated colors, the Hb rest frame equivalent
widths (EW), star formation histories (SFHs) and luminosity-weighted age (LWA)
maps finding no signs of current star formation throughout the disks of these
early-spiral/S0 galaxies. All of them have been passive for at least 20 Myr,
but their SF declined on different timescales. In most of them the outskirts
reached undetectable SFRs before the inner regions (outside-in quenching). Our
sample includes three post-starforming galaxies, two passive galaxies and three
galaxies with intermediate properties. The first population shows blue colors,
deep Hb in absorption (EW>>2.8A), young ages (8.8<log(LW [yr])<9.2). Two of
these galaxies show signs of a central SF enhancement before quenching. Passive
galaxies have instead red colors, EW(Hb)<2.8A, ages in the range
9.2<log(LWA[yr])<10. Finally, the other galaxies are most likely in transition
between a post starforming and passive phase, as they quenched in an
intermediate epoch and have not lost all the star forming features yet. The
outside-in quenching, the morphology and kinematics of the stellar component,
along with the position of these galaxies within massive clusters
(sigma_cl=550-950km/s) point to a scenario in which ram pressure stripping has
removed the gas, leading to quenching. Only the three most massive galaxies
might alternatively have entered the clusters already quenched. These galaxies
are therefore at the final stage of the rapid evolution galaxies undergo when
they enter the clusters.Comment: 24 pages, 10 figures accepted for publication in Ap
Joint Power Control and Structural Health Monitoring in Industry 4.0 Scenarios using Eclipse Arrowhead and Web of Things
The integration of legacy IoT ecosystems in Industry 4.0 scenarios requires human effort to adapt single devices. This process would highly benefit from features like device lookup, loose coupling and late binding. In this paper, we tackle the issue of integrating legacy monitoring systems and actuation systems in an industrial scenario, by looking into the Web of Things (WoT) as a communication standard and the Eclipse Arrowhead Framework (AHF) as a service orchestrator. More specifically, we propose a general architectural approach to enable closed-loop automation between the above mentioned legacy systems by leveraging the adaptation of the WoT to the AHF. Then, we develop a rule-based engine that enables the control of the actuation based on sensor values. Finally, we present a proof-of-concept use case where we integrate a Structural Health Monitoring (SHM) scenario with a power control actuation subsystem using the developed component
GASP XXX. The spatially resolved SFR-Mass relation in stripping galaxies in the local universe
The study of the spatially resolved Star Formation Rate-Mass
(Sigma_SFR-Sigma_M) relation gives important insights on how galaxies assemble
at different spatial scales. Here we present the analysis of the
Sigma_SFR-Sigma_M of 40 local cluster galaxies undergoing ram pressure
stripping drawn from the GAs Stripping Phenomena in galaxies (GASP) sample.
Considering their integrated properties, these galaxies show a SFR enhancement
with respect to undisturbed galaxies of similar stellar mass; we now exploit
spatially resolved data to investigate the origin and location of the excess.
Even on ~1kpc scales, stripping galaxies present a systematic enhancement of
Sigma_SFR (~0.35 dex at Sigma_M =108^M_sun/kpc^2) at any given Sigma_M compared
to their undisturbed counterparts. The excess is independent on the degree of
stripping and of the amount of star formation in the tails and it is visible at
all galactocentric distances within the disks, suggesting that the star
formation is most likely induced by compression waves from ram pressure. Such
excess is larger for less massive galaxies and decreases with increasing mass.
As stripping galaxies are characterised by ionised gas beyond the stellar disk,
we also investigate the properties of 411 star forming clumps found in the
galaxy tails. At any given stellar mass density, these clumps are
systematically forming stars at a higher rate than in the disk, but differences
are reconciled when we just consider the mass formed in the last few 10^8yr
ago, suggesting that on these timescales the local mode of star formation is
similar in the tails and in the disks.Comment: 20 pages, 13 figures, accepted for publication in Ap
Synthesis and Biological Evaluation (in Vitro and in Vivo) of Cyclic RGD Peptidomimetic - Paclitaxel Conjugates Targeting Integrin alphaVbeta3
A small library of integrin ligand - Paclitaxel conjugates 10-13 was synthesized with the aim of using the tumor-homing cyclo[DKP-RGD] peptidomimetics for site-directed delivery of the cytotoxic drug. All the Paclitaxel-RGD constructs 10-13 inhibited biotinylated vitronectin binding to the purified alphaVbeta3 integrin receptor at low nanomolar concentration and showed in vitro cytotoxic activity against a panel of human tumor cell lines similar to that of Paclitaxel. Among the cell lines, the cisplatin-resistant IGROV-1/Pt1 cells expressed high levels of integrin alphaVbeta3, making them attractive to be tested in in vivo models. Cyclo[DKP-f3-RGD]-PTX 11 displayed sufficient stability in physiological solution and in both human and murine plasma to be a good candidate for in vivo testing. In tumor-targeting experiments against the IGROV-1/Pt1 human ovarian carcinoma xenotransplanted in nude mice, compound 11 exhibited a superior activity than Paclitaxel, despite the lower (ca. half) molar dosage used
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