Mapping far-IR emission from the central kiloparsec of NGC 1097

Using photometry of NGC 1097 from the Herschel PACS (Photodetector Array Camera and Spectrometer) instrument, we study the resolved properties of thermal dust continuum emission from a circumnuclear starburst ring with a radius ~ 900 pc. These observations are the first to resolve the structure of a circumnuclear ring at wavelengths that probe the peak (i.e. lambda ~ 100 micron) of the dust spectral energy distribution. The ring dominates the far-infrared (far-IR) emission from the galaxy - the high angular resolution of PACS allows us to isolate the ring's contribution and we find it is responsible for 75, 60 and 55% of the total flux of NGC 1097 at 70, 100 and 160 micron, respectively. We compare the far-IR structure of the ring to what is seen at other wavelengths and identify a sequence of far-IR bright knots that correspond to those seen in radio and mid-IR images. The mid- and far-IR band ratios in the ring vary by less than +/- 20% azimuthally, indicating modest variation in the radiation field heating the dust on ~ 600 pc scales. We explore various explanations for the azimuthal uniformity in the far-IR colors of the ring including a lack of well-defined age gradients in the young stellar cluster population, a dominant contribution to the far-IR emission from dust heated by older (> 10 Myr) stars and/or a quick smoothing of local enhancements in dust temperature due to the short orbital period of the ring. Finally, we improve previous limits on the far-IR flux from the inner ~ 600 pc of NGC 1097 by an order of magnitude, providing a better estimate of the total bolometric emission arising from the active galactic nucleus and its associated central starburst.Comment: Accepted for publication in the A&A Herschel Special Editio

SSDSS IV MaNGA - Properties of AGN host galaxies

We present here the characterization of the main properties of a sample of 98 AGN host galaxies, both type-II and type-I, in comparison with those of about 2700 non-active galaxies observed by the MaNGA survey. We found that AGN hosts are morphologically early-type or early-spirals. For a given morphology AGN hosts are, in average, more massive, more compact, more central peaked and rather pressurethan rotational-supported systems. We confirm previous results indicating that AGN hosts are located in the intermediate/transition region between star-forming and non-star-forming galaxies (i.e., the so-called green valley), both in the ColorMagnitude and the star formation main sequence diagrams. Taking into account their relative distribution in terms of the stellar metallicity and oxygen gas abundance and a rough estimation of their molecular gas content, we consider that these galaxies are in the process of halting/quenching the star formation, in an actual transition between both groups. The analysis of the radial distributions of the starformation rate, specific star-formation rate, and molecular gas density shows that the quenching happens from inside-out involving both a decrease of the efficiency of the star formation and a deficit of molecular gas. All the intermediate data-products used to derive the results of our analysis are distributed in a database including the spatial distribution and average properties of the stellar populations and ionized gas, published as a Sloan Digital Sky Survey Value Added Catalog being part of the 14th Data Release: http://www.sdss.org/dr14/manga/manga-data/manga-pipe3d-value-added-catalog/Comment: 48 pages, 14 figures, in press in RMxA

Analyzing derived metallicities and ionization parameters from model-based determinations in ionized gaseous nebulae

We analyze the reliability of oxygen abundances and ionization parameters obtained from different diagnostic diagrams. For this, we compiled from the literature observational emission line intensities and oxygen abundance of 446 star-forming regions whose O/H abundance was determined by direct estimation of electron temperature. The abundances compiled were compared with the values calculated in this work using different diagnostic diagrams in combination with results from a grid of photoionization models. We found that the [\ion{O}{iii}]/[\ion{O}{ii}] vs. [\ion{N}{ii}]/[\ion{O}{ii}], [\ion{O}{iii}]/H$\beta$ vs. [\ion{N}{ii}]/[\ion{O}{ii}], and ([\ion{O}{iii}]/H$\beta$)/([\ion{N}{ii}]/H$\alpha$) vs. [\ion{S}{ii}]/[\ion{S}{iii}] diagnostic diagrams give O/H values close to the $T_{\rm e}$-method, with differences of about 0.04 dex and dispersion of about 0.3 dex. Similar results were obtained by detailed models but with a dispersion of 0.08 dex. The origin of the dispersion found in the use of diagnostic diagrams is probably due to differences between the real N/O-O/H relation of the sample and the one assumed in the models. This is confirmed by the use of detailed models that do not have a fixed N/O-O/H relation. We found no correlation between ionization parameter and the metallicity for the objects of our sample. We conclude that the combination of two line ratio predicted by photoionization models, one sensitive to the metallicity and another sensitive to the ionization parameter, which takes into account the physical conditions of star-forming regions, gives O/H estimates close to the values derived using direct detections of electron temperatures.Comment: 12 pages, 9 figures, accepted by MNRA

Scientific Objectives of Einstein Telescope

The advanced interferometer network will herald a new era in observational astronomy. There is a very strong science case to go beyond the advanced detector network and build detectors that operate in a frequency range from 1 Hz-10 kHz, with sensitivity a factor ten better in amplitude. Such detectors will be able to probe a range of topics in nuclear physics, astronomy, cosmology and fundamental physics, providing insights into many unsolved problems in these areas.Comment: 18 pages, 4 figures, Plenary talk given at Amaldi Meeting, July 201

Italian pool of asbestos workers cohorts: asbestos related mortality by industrial sector and cumulative exposure

Objective. Italy has been a large user of asbestos and asbestos containing materials until the 1992 ban. We present a pooled cohort study on long-term mortality in exposed workers. Methods. Pool of 43 Italian asbestos cohorts (asbestos cement, rolling stock, shipbuilding, glasswork, harbors, insulation and other industries). SMRs were computed by industrial sector for the 1970-2010 period, for the major causes, using reference rates by age, sex, region and calendar period. Results. The study included 51 801 subjects (5741 women): 55.9% alive, 42.6% died (cause known for 95%) and 1.5% lost to follow-up. Asbestos exposure was estimated at the plant and period levels. Asbestos related mortality was significantly increased. All industrial sectors showed increased mortality from pleural malignancies, and most als

Chemical abundances in Seyfert galaxies – V. The discovery of shocked emission outside the AGN ionization axis

We present maps for the electron temperature in the inner kpc of three luminous Seyfert galaxies: Mrk 79, Mrk 348, and Mrk 607 obtained from Gemini Multi-Object Spectrograph-integral field unit observations at spatial resolutions of ∼110–280 pc. We study the distributions of electron temperature in active galaxies and find temperatures varying in the range from ∼8000 to ≳30000K. Shocks due to gas outflows play an important role in the observed temperature distributions of Mrk 79 and Mrk 348, while standard photoionization models reproduce the derived temperature values for Mrk 607. In Mrk 79 and Mrk 348, we find direct evidence for shock ionization with overall orientation orthogonal to the ionization axis, where shocks can be easily observed as the active galactic nuclei radiation field is shielded by the nuclear dusty torus. This also indicates that even when the ionization cones are narrow, the shocks can be much wider angle. © 2020 The Author(s).This study was financed in part by CNPq, FAPERGS, and FAPESP. AF acknowledges the support from grant PRIN MIUR2017-20173ML3WW−001. EPM acknowledges financial support from the project ‘Estallidos6’ AYA2016-79724-C4. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NationalScience Foundation (United States), National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea).With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.Peer reviewe

Cumulative asbestos exposure and mortality from asbestos related diseases in a pooled analysis of 21 asbestos cement cohorts in Italy

Background: Despite the available information on cancer risk, asbestos is used in large areas in the world, mostly in the production of asbestos cement. Moreover, questions are raised regarding the shape of the dose response relation, the relation with time since exposure and the association with neoplasms in various organs. We conducted a study on the relationship between cumulative asbestos exposure and mortality from asbestos related diseases in a large Italian pool of 21 cohorts of asbestos-cement workers with protracted exposure to both chrysotile and amphibole asbestos. Methods: The cohort included 13,076 workers, 81.9% men and 18.1% women, working in 21 Italian asbestos-cement factories, with over 40 years of observation. Exposure was estimated by plant and period, and weighted for the type of asbestos used. Data were analysed with consideration of cause of death, cumulative exposure and time since first exposure (TSFE), and by gender. SMRs were computed using reference rates by region, gender and calendar time. Poisson regression models including cubic splines were used to analyse the effect of cumulative exposure to asbestos and TSFE on mortality for asbestos-related diseases. 95% Confidence Intervals (CI) were computed according to the Poisson distribution. Results: Mortality was significantly increased for ‘All Causes’ and ‘All Malignant Neoplasm (MN)’, in both genders. Considering asbestos related diseases (ARDs), statistically significant excesses were observed for MN of peritoneum (SMR: men 14.19; women 15.14), pleura (SMR: 22.35 and 48.10), lung (SMR: 1.67 and 1.67), ovary (in the highest exposure class SMR 2.45), and asbestosis (SMR: 507 and 1023). Mortality for ARDs, in particular pleural and peritoneal malignancies, lung cancer, ovarian cancer and asbestosis increased monotonically with cumulative exposure. Pleural MN mortality increased progressively in the first 40 years of TSFE, then reached a plateau, while peritoneal MN showed a continuous increase. The trend of lung cancer SMRs also showed a flattening after 40 years of TSFE. Attributable proportions for pleural, peritoneal, and lung MN were respectively 96, 93 and 40%. Conclusions: Mortality for ARDs was associated with cumulative exposure to asbestos. Risk of death from pleural MN did not increase indefinitely with TSFE but eventually reached a plateau, consistently with reports from other recent studie

Constraints on the broad-line region properties and extinction in local Seyferts

We use high-spectral resolution (R > 8000) data covering 3800–13 000 Å to study the physical conditions of the broad-line region (BLR) of nine nearby Seyfert 1 galaxies. Up to six broad H i lines are present in each spectrum. A comparison – for the first time using simultaneous optical to near-infrared observations – to photoionization calculations with our devised simple scheme yields the extinction to the BLR at the same time as determining the density and photon flux, and hence distance from the nucleus, of the emitting gas. This points to a typical density for the H i emitting gas of 1011 cm−3 and shows that a significant amount of this gas lies at regions near the dust sublimation radius, consistent with theoretical predictions. We also confirm that in many objects, the line ratios are far from case B, the best-fitting intrinsic broad-line Hα/H β ratios being in the range 2.5–6.6 as derived with our photoionization modelling scheme. The extinction to the BLR, based on independent estimates from H i and He ii lines, is AV ≤ 3 for Seyfert 1–1.5s, while Seyfert 1.8–1.9s have AV in the range 4–8. A comparison of the extinction towards the BLR and narrow-line region (NLR) indicates that the structure obscuring the BLR exists on scales smaller than the NLR. This could be the dusty torus, but dusty nuclear spirals or filaments could also be responsible. The ratios between the X-ray absorbing column NH and the extinction to the BLR are consistent with the Galactic gas-to-dust ratio if NH variations are considered

The Fueling and Evolution of AGN: Internal and External Triggers

In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte