338 research outputs found

    Evidence for Orbital Motion of Material Close to the Central Black Hole of Mrk 766

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    Time-resolved X-ray spectroscopy has been obtained for the narrow line Seyfert galaxy Mrk766 from XMM-Newton observations. We present analysis in the energy-time plane of EPIC pn data in the 4-8 keV band with energy resolution R~50. A component of Fe Ka emission detected in the maps shows a variation of photon energy with time that appears both to be statistically significant and to be consistent with sinusoidal variation. We investigate the interpretation that there exists a component of line emission from matter in a Keplerian orbit around a supermassive black hole. The orbit has a period ~165 ks and a line-of-sight velocity ~13,500 km/s. This yields a lower limit for the central mass of M > 4.9x10^5 solar masses within a radius of 3.6 x 10^13 cm (2.4 A.U.). The orbit parameters are consistent with higher black hole masses, but the lack of any substantial gravitational redshift of the orbit implies an upper limit to the black hole mass of 4.5x10^7 solar masses.Comment: 20 pages, 6 figures (some colour). Accepted for publication in A&A. Only minor changes since V1 (including reordering of Figs 1a & b

    A Multi-Wavelength Study of the Nature of Type 1.8/1.9 Seyfert Galaxies

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    We focus on determining the underlying physical cause of a Seyfert galaxy's appearance as type a 1.8 or 1.9. Are these "intermediate" Seyfert types typical Seyfert 1 nuclei with reddened broad-line regions? Or are they objects with intrinsically weak continua and broad emission lines? We compare measurements of the optical reddening of the narrow and broad-line regions with each other and with the X-ray column derived from XMM-Newton 0.5-10 keV spectra to determine the presence and location of dust in the line of sight. We also searched the literature to see if the objects showed evidence for broad-line variability, and determined if the changes were consistent with a change in reddening or a change in the intrinsic ionizing continuum flux. We find that 10 of 19 objects previously classified as Seyfert 1.8/1.9s received this designation due to their low continuum flux. In four objects the classification was due to BLR reddening, either by the torus or dust structures in the vicinity of the NLR; in the remaining five objects there is not sufficient evidence to favor one scenario over the other. These findings imply that, in general, samples of 1.8/1.9s are not suitable for use in studies of the gas and dust in the central torus.Comment: 85 pages, accepted by Ap

    Effect of COVID-19 pandemic on utilisation of community-based mental health care in North-East of Italy: A psychiatric case register study

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    Aims: WHO declared that mental health care should be considered one essential health service to be maintained during the coronavirus disease 2019 (COVID-19) pandemic. This study aims to describe the effect of lockdown and restrictions due to the COVID-19 pandemic in Italy on mental health services' utilisation, by considering psychiatric diagnoses and type of mental health contacts. Methods: The study was conducted in the Verona catchment area, located in the Veneto region (northeastern Italy). For each patient, mental health contacts were grouped into: (1) outpatient care, (2) social and supportive interventions, (3) rehabilitation interventions, (4) multi-professional assessments, (5) day care. A 'difference in differences' approach was used: difference in the number of contacts between 2019 and 2020 on the weeks of lockdown and intermediate restrictions was compared with the same difference in weeks of no or reduced restrictions, and such difference was interpreted as the effect of restrictions. Both a global regression on all contacts and separate regressions for each type of service were performed and Incidence Rate Ratios (IRRs) were calculated. Results: In 2020, a significant reduction in the number of patients who had mental health contacts was found, both overall and for most of the patients' characteristics considered (except for people aged 18-24 years for foreign-born population and for those with a diagnosis of schizophrenia. Moreover, in 2020 mental health contacts had a reduction of 57 096 (-33.9%) with respect to 2019; such difference remained significant across the various type of contacts considered, with rehabilitation interventions and day care showing the greatest reduction. Negative Binomial regressions displayed a statistically significant effect of lockdown, but not of intermediate restrictions, in terms of reduction in the number of contacts. The lockdown period was responsible of a 32.7% reduction (IRR 0.673; p-value <0.001) in the overall number of contacts. All type of mental health contacts showed a reduction ascribable to the lockdown, except social and supportive interventions. Conclusions: Despite the access to community mental health care during the pandemic was overall reduced, the mental health system in the Verona catchment area was able to maintain support for more vulnerable and severely ill patients, by providing continuity of care and day-by-day support through social and supportive interventions

    Balmer Emission Line Profiles and the Complex Properties of Broad Line Regions in Active Galactic Nuclei

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    In this work we analyze a sample of AGN spectra, selected from the 6th Data Release of the Sloan Digital Sky Survey, exploiting a generalized technique of line profile analysis, designed to take into account the whole profiles of their broad emission lines. We find that the line profile broadening functions result from a complex structure, but we may be able to infer some constraints about the role of the geometrical factor, thus improving our ability to estimate AGN properties and their relation with the host galaxy. Our results suggest that flattening and inclination within the structure of the Broad Line Region (BLR) must be taken into account. We detect low inclinations of the BLR motion plane with respect to our line of sight, typically i < 20 degrees, with a geometrical effect which generally decreases as the line profile becomes broader.Comment: 13 pages, 11 figures, updated reference list. ApJ accepte

    3D Spectroscopic Study of the Line Emitting Regions of Mrk 493

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    We report the results of 3D spectroscopic observations of Mrk 493 (NLS1 galaxy) with the integral-field spectrograph MPFS of the SAO RAS 6-m telescope. The difference in the slope of the optical continuum emission intensity across the nucleus part and an extensive continuum emission region} is detected. The emission in lines (Hα\alpha, HÎČ\beta, [OIII], etc.) coincides with a composite nuclear region: an AGN plus a circum-nuclear star-forming ring observed in the HST UV/optical images. The [SII] emission region tends to be up to 1kpc around the center. The Hα\alpha and HÎČ\beta could be decomposed into three components (broad ∌\sim 2000 km/s. intermediate ∌\sim 700 km/s and narrow ∌\sim 250 km/s). We found that width (∌\sim 750 km/s) of the Fe II lines correspond to the intermediate component, that may indicate a non-BLR origin of the Fe II lines, or that a large fraction of the Fe II emission arise in the outher parts of the BLR. The weak broad component detected in the Hα\alpha, HÎČ\beta and Heλ\lambda4686 may come from the unresolved central BLR, but also partly produced by violent starburst in the circum-nuclear ring. Moreover, diagnostic diagrams clearly show presence of the HII regions (not a Sy 1 nucleus) in the NLR of Mrk 493.Comment: accepted in A

    The CaT strength in Seyfert nuclei revisited: analyzing young stars and non-stellar light contributions to the spectra

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    In a former paper (Garcia-Rissmann et al. 2005; hereafter Paper I), we have presented spectra of 64 active, 9 normal and 5 Starburst galaxies in the region around the near-IR Calcium triplet absorption lines and the [SIII]9069 line. In the present paper we analyze the CaT strength (WCaT), and kinematical products derived in that study, namely stellar and ionized gas velocity dispersions. Our main results may be summarized as follows: (1) Seyfert 2s show no sign of dilution in WCaT with respect to the values spanned by normal galaxies, even when optical absorption lines such as the CaII K band at 3933 A are much weaker than in old, bulge-like stellar populations. (2) The location of Seyfert 2s in the WCaT-WCaK plane is consistent with evolutionary synthesis models. The implication is that the source responsible for the dilution of optical lines in these AGN is a young stellar population, rather than an AGN featureless continuum, confirming the conclusion of the pioneer study of Terlevich, Diaz & Terlevich. (3) In Seyfert 1s, both W[SIII] and WCaT tend to be diluted due to the presence of a non-stellar component, in agreement with the unification paradigm. (4) A comparison of stellar and gas velocity dispersions confirms the existence of a correlation between the typical velocities of stars and clouds of the Narrow Line Region. The strength and scatter around this correlation are similar to those previously obtained from the [OIII]5007 line width.Comment: 14 pages, 15 figures. Paper accepted for publication in MNRA

    On the cosmic evolution of the scaling relations between black holes and their host galaxies: Broad Line AGN in the zCOSMOS survey

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    (Abriged) We report on the measurement of the rest frame K-band luminosity and total stellar mass of the hosts of 89 broad line Active Galactic Nuclei detected in the zCOSMOS survey in the redshift range 1<z<2.2. The unprecedented multiwavelength coverage of the survey field allows us to disentangle the emission of the host galaxy from that of the nuclear black hole in their Spectral Energy Distributions. We derive an estimate of black hole masses through the analysis of the broad Mg II emission lines observed in the medium-resolution spectra taken with VIMOS/VLT as part of the zCOSMOS project. We found that, as compared to the local value, the average black hole to host galaxy mass ratio appears to evolve positively with redshift, with a best fit evolution of the form (1+z)^{0.68 \pm0.12 +0.6 -0.3}, where the large asymmetric systematic errors stem from the uncertainties in the choice of IMF, in the calibration of the virial relation used to estimate BH masses and in the mean QSO SED adopted. A thorough analysis of observational biases induced by intrinsic scatter in the scaling relations reinforces the conclusion that an evolution of the MBH-M* relation must ensue for actively growing black holes at early times: either its overall normalization, or its intrinsic scatter (or both) appear to increase with redshift. This can be interpreted as signature of either a more rapid growth of supermassive black holes at high redshift, a change of structural properties of AGN hosts at earlier times, or a significant mismatch between the typical growth times of nuclear black holes and host galaxies.Comment: 47 pages, 8 figures. Accepted for publication in Ap

    Systems biology approaches applied to regenerative medicine

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    Systems biology is the creation of theoretical and mathematical models for the study of biological systems, as an engine for hypothesis generation and to provide context to experimental data. It is underpinned by the collection and analysis of complex datasets from different biological systems, including global gene, RNA, protein and metabolite profiles. Regenerative medicine seeks to replace or repair tissues with compromised function (for example, through injury, deficiency or pathology), in order to improve their functionality. In this paper, we will address the application of systems biology approaches to the study of regenerative medicine, with a particular focus on approaches to study modifications to the genome, transcripts and small RNAs, proteins and metabolites

    New photometric and spectroscopic observations of the Seyfert galaxy Mrk 315

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    We present new important results about the intermediate-type Seyfert galaxy Mrk 315, recently observed through optical imaging and integral-field spectroscopy. Broad-band images were used to study the morphology of the host galaxy, narrow-band H-alpha images to trace the star forming regions, and middle-band [O III] images to evidence the distribution of the highly ionised gas. Some extended emission regions were isolated and their physical properties studied by means of flux calibrated spectra. High resolution spectroscopy was used to separate different kinematic components in the velocity fields of gas and stars. Some peculiar features characterise this apparently undisturbed and moderately isolated active galaxy. Such features, already investigated by other authors, are re-analysed and discussed in the light of these new observations. The most relevant results we obtained are: the multi-tiers structure of the disc; the presence of a quasi-ring of regions with star formation much higher than previous claims; a secondary nucleus confirmed by a stellar component kinematically decoupled by the main galaxy; a new hypothesis about the controversial nature of the long filament, initially described as hook-shaped, and more likely made of two independent filaments caused by interaction events between the main galaxy and two dwarf companions.Comment: 14 pages, 16 figures (7 figures in jpeg format), accepted for publication in MNRA
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