Jets and outflows in Radio Galaxies: implications for AGN feedback

One of the main debated astrophysical problems is the role of the AGN feedback in galaxy formation. It is known that massive black holes have a profound effect on the formation and evolution of galaxies, but how black holes and galaxies communicate is still an unsolved problem. For Radio Galaxies, feedback studies have mainly focused on jet/cavity systems in the most massive and X-ray luminous galaxy clusters. The recent high-resolution detection of warm absorbers in some Broad Line Radio Galaxies allow us to investigate the interplay between the nuclear engine and the surrounding medium from a different perspective. We report on the detection of warm absorbers in two Broad Line Radio Galaxies, 3C 382 and 3C 390.3, and discuss the physical and energetic properties of the absorbing gas. Finally, we attempt a comparison between radio-loud and radio-quiet outflows.Comment: To be published in the proceedings of High Energy Phenomena in Relativistic Outflows III (HEPRO III, IJMPCS). 4 pages, 2 figure

Statistical equilibrium in simple exchange games I

Simple stochastic exchange games are based on random allocation of finite resources. These games are Markov chains that can be studied either analytically or by Monte Carlo simulations. In particular, the equilibrium distribution can be derived either by direct diagonalization of the transition matrix, or using the detailed balance equation, or by Monte Carlo estimates. In this paper, these methods are introduced and applied to the Bennati-Dragulescu-Yakovenko (BDY) game. The exact analysis shows that the statistical-mechanical analogies used in the previous literature have to be revised.Comment: 11 pages, 3 figures, submitted to EPJ

ISM composition through X-ray spectroscopy of LMXBs

The diffuse interstellar medium (ISM) is an integral part of the evolution of the entire Galaxy. Metals are produced by stars and their abundances are the direct testimony of the history of stellar evolution. However, the interstellar dust composition is not well known and the total abundances are yet to be accurately determined. We probe ISM dust composition, total abundances, and abundance gradients through the study of interstellar absorption features in the high-resolution X-ray spectra of Galactic low-mass X-ray binaries (LMXBs). We use high-quality grating spectra of nine LMXBs taken with XMM-Newton. We measure the column densities of O, Ne, Mg, and Fe with an empirical model and estimate the Galactic abundance gradients. The column densities of the neutral gas species are in agreement with those found in the literature. Solids are a significant reservoir of metals like oxygen and iron. Respectively, 15-25 % and 65-90 % of the total amount of O I and Fe I is found in dust. The dust amount and mixture seem to be consistent along all the lines-of-sight (LOS). Our estimates of abundance gradients and predictions of local interstellar abundances are in agreement with those measured at longer wavelengths. Our work shows that X-ray spectroscopy is a very powerful method to probe the ISM. For instance, on a large scale the ISM appears to be chemically homogeneous showing similar gas ionization ratios and dust mixtures. The agreement between the abundances of the ISM and the stellar objects suggests that the local Galaxy is also chemically homogeneous.Comment: 13 pages, 10 figures, 5 tables, accepted to A&

A longer XMM-Newton look at I Zwicky 1: Distinct modes of X-ray spectral variability

The short-term spectral variability of the narrow-line Seyfert 1 galaxy I Zwicky 1 (I Zw 1) as observed in an 85 ks XMM-Newton observation is discussed in detail. I Zw 1 shows distinct modes of variability prior to and after a flux dip in the broad-band light curve. Before the dip the variability can be described as arising from changes in shape and normalisation of the spectral components. Only changes in normalisation are manifested after the dip. The change in the mode of behaviour occurs on dynamically short timescales in I Zw 1. The data suggest that the accretion-disc corona in I Zw 1 could have two components that are co-existing. The first, a uniform, physically diffuse plasma responsible for the "typical'' long-term (e.g. years) behaviour; and a second compact, centrally located component causing the rapid flux and spectral changes. This compact component could be the base of a short or aborted jet as sometimes proposed for radio-quiet active galaxies. Modelling of the average and time-resolved rms spectra demonstrate that a blurred Compton-reflection model can describe the spectral variability if we allow for pivoting of the continuum component prior to the dip.Comment: 8 pages, 9 figures. Accepted by MNRA

Chandra imaging of the ∼\simkpc extended outflow in 1H 0419-577

The Seyfert 1 galaxy 1H 0419-577 hosts a $\sim$kpc extended outflow that is evident in the [\ion{O}{iii}] image and that is also detected as a warm absorber in the UV/X-ray spectrum. Here, we analyze a $\sim$30 ks Chandra-ACIS X-ray image, with the aim of resolving the diffuse extranuclear X-ray emission and of investigating its relationship with the galactic outflow. Thanks to its sub-arcsecond spatial resolution, Chandra resolves the circumnuclear X-ray emission, which extends up to a projected distance of at least $\sim$16 kpc from the center. The morphology of the diffuse X-ray emission is spherically symmetrical. We could not recover a morphological resemblance between the soft X-ray emission and the ionization bicone that is traced by the [\ion{O}{iii}] outflow. we argue that the photoionized gas nebula must be distributed mostly along the polar directions, outside our line of sight. In this geometry, the X-ray/UV warm absorber must trace a different gas component, physically disconnected from the emitting gas, and located closer to the equatorial plane.Comment: accepted for publications A&

An X-ray view of Mrk 705: A borderline narrow-line Seyfert 1 galaxy

Mrk 705 exhibits optical properties of both narrow- and broad-line Seyfert 1 galaxies. We examine the X-ray properties of this borderline object utilising proprietary and public data from Chandra, ASCA, ROSAT and RXTE, spanning more than twelve years. Though long-term flux variability from the pointed observations appears rather modest (about 3 times), we do find examples of rare large amplitude outbursts in the RXTE monitoring data. There is very little evidence of long-term spectral variability as the low- and high-energy spectra appear constant with time. A 6.4 keV emission line is detected in the ASCA spectra of Mrk 705, but not during the later, higher flux state Chandra observation. However, the upper limit on the equivalent width of a line in the Chandra spectrum is consistent with a constant-flux emission line and a brighter continuum, suggesting that the line is emitted from distant material such as the putative torus. Overall, the X-ray properties of Mrk 705 appear typical of BLS1 activity.Comment: 7 pages, 7 figures. Accepted for publication in A&A (Research Note

Body posture differentially impacts on visual attention towards tool, graspable, and non-graspable objects.

Viewed objects have been shown to afford suitable actions, even in the absence of any intention to act. However, little is known as to whether gaze behavior (i.e., the way we simply look at objects) is sensitive to action afforded by the seen object and how our actual motor possibilities affect this behavior. We recorded participants’ eye movements during the observation of tools, graspable and ungraspable objects, while their hands were either freely resting on the table or tied behind their back. The effects of the observed object and hand posture on gaze behavior were measured by comparing the actual fixation distribution with that predicted by 2 widely supported models of visual attention, namely the Graph-Based Visual Saliency and the Adaptive Whitening Salience models. Results showed that saliency models did not accurately predict participants’ fixation distributions for tools. Indeed, participants mostly fixated the action-related, functional part of the tools, regardless of its visual saliency. Critically, the restriction of the participants’ action possibility led to a significant reduction of this effect and significantly improved the model prediction of the participants’ gaze behavior. We suggest, first, that action-relevant object information at least in part guides gaze behavior. Second, postural information interacts with visual information to the generation of priority maps of fixation behavior. We support the view that the kind of information we access from the environment is constrained by our readiness to act

Italian validation of CoViD-19 Peritraumatic Distress Index and preliminary data in a sample of general population [Validazione italiana del CoViD-19 Peritraumatic Distress Index e dati preliminari in un campione di popolazione generale]

Introduzione. Il distress peritraumatico è un importante predittore del disturbo da stress post-traumatico e sebbene per la sua misurazione siano disponibili diversi questionari, nessuno di questi è specifico per CoViD-19. Il CoViD-19 Peritraumatic Distress Index (CPDI), recentemente sviluppato in Cina, si caratterizza come strumento di rapida compilazione (10 minuti), facilmente comprensibile e apprezzato dalle persone. Scopo. Obiettivi di questo studio sono stati: 1) la validazione della versione italiana del CPDI e 2) la misura della prevalenza di stress peritraumatico in questa fase CoViD-19. Metodi. Per la traduzione del CPDI è stata utilizzata la procedura standard della forward-backward translation.Il questionario è stato poi somministrato online a 329 persone (191 di genere femminile e 137 di genere maschile, età media=46,49±13,58 anni). Il CPDI ha mostrato una coerenza interna, misurata con l’alpha di Cronbach, pari a 0,916. La validità del contenuto è stata giudicata soddisfacente da due psicologhe esperte di stress e trauma. La validità del costrutto è data dall’elevata correlazione con le dimensioni di Intrusione, Evitamento e Iperarousal come misurate dall’Impact of Event Scale-Revised (r=0,63, r=0,57, r=0,71, rispettivamente). Risultati. I risultati emersi dal nostro studio sono paragonabili a quelli cinesi. Un terzo delle persone ha manifestato sintomi di distress peritraumatico lieve/moderato e grave. Le femmine hanno punteggi più elevati dei maschi. Le persone anziane sono più resistenti di quelle più giovani, così come quelle che sono state in quarantena rispetto a quelle che non ci sono state. Dal modello di regressione logistica multivariata emerge che punteggi maggiori di distress sono associati a uso di psicofarmaci (AOR=4,28; IC 95%=1,55-11,85), utilizzo di rimedi per dormire (AOR=4,05;IC 95%=2,07-7,94), preoccuparsi di morire in caso di contagio CoViD-19 (AOR=3,33;IC 95%=1,83- 6,06), genere femminile (AOR=2,95; IC 95%=1,58-5,53), credo religioso (AOR=1,97; IC 95%=1,05-3,70). Avere un’età dai 51 ai 71 anni, essere stati in quarantena e aver ricevuto supporto psicologico sono variabili risultate associate a bassi punteggi di distress. Conclusioni. Le caratteristiche psicometriche della versione italiana sono risultate soddisfacenti e confermano che il CPDI è uno strumento veloce, non invasivo, che può essere somministrato online e quindi “sicuro” in una fase ad alto rischio di contagio. Permette, come una termografia psichica, di rilevare rapidamente i bisogni della popolazione e proporre interventi altrettanto rapidi.Introduction. Peritraumatic distress is an important predictor of post-traumatic stress disorder and although several questionnaires are available for its measurement, none of these are specific to CoViD-19. The new CoViD-19 Peritraumatic Distress Index (CPDI), developed in China, is characterized as a rapid compilation tool (10 minutes), easily understandable and appreciated by people. Aim. The objectives of this study were: (1) the validation of the Italian version of the CPDI, and (2) the measurement of the prevalence of peritraumatic distress in this phase 1 CoViD-19. Method. CPDI has been translated using a standard forward-backward-translation procedure and offered online to 329 people (191 females and 137 males, aged 46.49 ± 13.58 years). The CPDI showed an internal-consistency of Cronbach’s α=0.916. Content validity was judged satisfactory by two psychologists experienced in stress and trauma. The construct validity is given by the high correlation with the dimensions of Intrusion, Avoidance and Hyperarousal as measured by the Impact of Event Scale-Revised (r=0.63, r=0.57, r=0.71, respectively). Results. Our results are comparable to the Chinese ones. A third of people experienced symptoms of mild/moderate and severe peritraumatic distress. Females have higher scores, compared to males. Older people are more resilient, compared to younger, and those who have been in quarantine report less distress than those didn’t, as evidenced by the results of the multivariate logistic regression model. High distress was associated with use of psychotropic drugs (AOR=4.28; 95% CI=1.55-11.85), sleeping remedies (AOR=4.05; 95% CI=2.07-7.94), be worried about dying in case of contagion CoViD-19 (AOR=3.33; 95% CI=1.83-6.06), female gender (AOR=2.95; 95% CI=1.58-5.53) and have a religious belief (AOR=1.97; 95% CI=1.05-3.70). To be aged 51-71 years, to have been in quarantine and to have received psychological support were variables associated with lower distress scores. Conclusions. The psychometric properties of the Italian version are satisfactory and confirm that CPDI is a tool fast, non-intrusive, administered online, and therefore ‘safe’ in a phase with a high risk of contagion. It allows, like a psychic thermoscan, to quickly detect the needs of the population and propose equally rapid interventions

A reconstruction method for anisotropic universes in unimodular F(R)F(R)-gravity

An extension of unimodular Einsteinian gravity in the context of $F(R)$ gravities is used to construct a class of anisotropic evolution scenarios. In unimodular GR the determinant of the metric is constrained to be a fixed number or a function. However, the metric of a generic anisotropic universe is not compatible with the unimodular constraint, so that a redefinition of the metric, to properly take into account the constraint, need be performed. The unimodular constraint is imposed on $F(R)$ gravity in the Jordan frame by means of a Lagrangian multiplier, to get the equations of motion. The resulting equations can be viewed as a reconstruction method, which allows to determine what function of the Ricci scalar can realize the desired evolution. For the sake of clarity, some characteristic examples are invoked to show how this reconstruction method works explicitly. The de Sitter spacetime here considered, in the context of unimodular $F(R)$ gravity, is suitable to describe both the early- and late-time epochs of the universe history.Comment: EPJC Accepte