The Iron Line Background

We investigate the presence of iron line emission among faint X-ray sources identified in the 1Ms Chandra Deep Field South and in the 2Ms Chandra Deep Field North. Individual source spectra are stacked in seven redshift bins over the range z=0.5-4. We find that iron line emission is an ubiquitous property of X-ray sources up to z~3. The measured line strengths are in good agreement with those expected by simple pre-Chandra estimates based on X-ray background synthesis models. The average rest frame equivalent width of the iron line does not show significant changes with redshift.Comment: 5 pages, 2 figures, ApJ Letters in press (include emulateapj.sty

When home and work are not enough. The challenge of international migrants' agency in the Italian Alps

Even when they have access to housing and employment, international migrants struggle to develop their own agency, i.e. the capacity to act in their own life contexts, exercising citizenship rights within substantive inclusion processes in the wider communities. The territorial context in fact, especially in rural and mountainous areas such as the Alpine ones analysed here, seems in many ways to represent a limit to the development of capacities and exercise of rights. Difficulties in accessing public space and public sphere, scarce social recognition, low status, housing isolation (as is the case of those who live in small mountain villages), professional ghettoisation: these are factors that, even in presence of an acceptable working and housing inclusion, make it difficult for international migrants to exercise their rights, to have their skills recognised, and, ultimately, to develop an agency genuinely linked to their capabilities. In this article, with reference to the action-research activities carried out in 2020-22 by the Horizon2020 MATILDE project in the Italian Alpine areas of South Tyrol and the Metropolitan City of Turin, attention is focused on the policies that could favour the effective migrants’ agency in mountain territories.The paper is published by the European Journal of Spatial Development (EJSD). The previous version of the journal was host by Nordregio

When home and work are not enough. The challenge of international migrants' agency in the Italian Alps

Even when they have access to housing and employment, international migrants struggle to develop their own agency, i.e. the capacity to act in their own life contexts, exercising citizenship rights within substantive inclusion processes in the wider communities. The territorial context in fact, especially in rural and mountainous areas such as the Alpine ones analysed here, seems in many ways to represent a limit to the development of capacities and exercise of rights. Difficulties in accessing public space and public sphere, scarce social recognition, low status, housing isolation (as is the case of those who live in small mountain villages), professional ghettoisation: these are factors that, even in presence of an acceptable working and housing inclusion, make it difficult for international migrants to exercise their rights, to have their skills recognised, and, ultimately, to develop an agency genuinely linked to their capabilities. In this article, with reference to the action-research activities carried out in 2020-22 by the Horizon2020 MATILDE project in the Italian Alpine areas of South Tyrol and the Metropolitan City of Turin, attention is focused on the policies that could favour the effective migrants’ agency in mountain territories.The paper is published by the European Journal of Spatial Development (EJSD). The previous version of the journal was host by Nordregio

X-ray spectroscopy of the z=6.4 quasar J1148+5251

We present the 78-ks Chandra observations of the $z=6.4$ quasar SDSS J1148+5251. The source is clearly detected in the energy range 0.3-7 keV with 42 counts (with a significance $\gtrsim9\sigma$). The X-ray spectrum is best-fitted by a power-law with photon index $\Gamma=1.9$ absorbed by a gas column density of $\rm N_{\rm H}=2.0^{+2.0}_{-1.5}\times10^{23}\,\rm cm^{-2}$. We measure an intrinsic luminosity at 2-10 keV and 10-40 keV equal to $\sim 1.5\times 10^{45}~\rm erg~s^{-1}$, comparable with luminous local and intermediate-redshift quasar properties. Moreover, the X-ray to optical power-law slope value ($\alpha_{\rm OX}=-1.76\pm 0.14$) of J1148 is consistent with the one found in quasars with similar rest-frame 2500 \AA ~luminosity ($L_{\rm 2500}\sim 10^{32}~\rm erg~s^{-1}$\AA$^{-1}$). Then we use Chandra data to test a physically motivated model that computes the intrinsic X-ray flux emitted by a quasar starting from the properties of the powering black hole and assuming that X-ray emission is attenuated by intervening, metal-rich ($Z\geq \rm Z_{\odot}$) molecular clouds distributed on $\sim$kpc scales in the host galaxy. Our analysis favors a black hole mass $M_{\rm BH} \sim 3\times 10^9 \rm M_\odot$ and a molecular hydrogen mass $M_{\rm H_2}\sim 2\times 10^{10} \rm M_\odot$, in good agreement with estimates obtained from previous studies. We finally discuss strengths and limits of our analysis.Comment: 9 pages, 3 figures, 1 table, MNRAS in pres

Vom Lernprozess des Ärztenetzwerks xundart: Innovative und wissenschaftlich fundierte Qualitätsentwicklung

Systemische und reflexive Qualitätsentwicklung ist ein Anliegen des Ostschweizer Ärztenetzwerks xundart. Gerade nicht-quantitative Qualitätsarbeit erfordert von den Mitgliedern einer Organisation Vertrauen, Offenheit zur Selbst- und Fremdbeobachtung und die Bereitschaft, aus den eigenen Komfortzonen herauszutreten. Vonseiten der Verantwortlichen sind sorgfältige Kommunikationsarbeit, Fingerspitzengefühl und Geduld gefragt

The Obscured Fraction of AGN in the XMM-COSMOS Survey: A Spectral Energy Distribution Perspective

The fraction of AGN luminosity obscured by dust and re-emitted in the mid-IR is critical for understanding AGN evolution, unification, and parsec-scale AGN physics. For unobscured (Type-1) AGN, where we have a direct view of the accretion disk, the dust covering factor can be measured by computing the ratio of re-processed mid-IR emission to intrinsic nuclear bolometric luminosity. We use this technique to estimate the obscured AGN fraction as a function of luminosity and redshift for 513 Type-1 AGN from the XMM-COSMOS survey. The re-processed and intrinsic luminosities are computed by fitting the 18-band COSMOS photometry with a custom SED-fitting code, which jointly models emission from: hot-dust in the AGN torus, the accretion disk, and the host-galaxy. We find a relatively shallow decrease of the luminosity ratio as a function of Lbol, which we interpret as a corresponding decrease in the obscured fraction. In the context of the receding torus model, where dust sublimation reduces the covering factor of more luminous AGN, our measurements require a torus height which increases with luminosity as h ~ Lbol^{0.3-0.4}. Our obscured fraction-luminosity relation agrees with determinations from SDSS censuses of Type-1 and Type-2 quasars, and favors a torus optically thin to mid-IR radiation. We find a much weaker dependence of obscured fraction on 2-10 keV luminosity than previous determinations from X-ray surveys, and argue that X-ray surveys miss a significant population of highly obscured Compton-thick AGN. Our analysis shows no clear evidence for evolution of obscured fraction with redshift.Comment: 33 pages, 24 figures, ApJ accepte

The Hard X-Ray Luminosity Function of High-Redshift (3<z≲53<z\lesssim 5) Active Galactic Nuclei

We present the hard-band ($2-10\,\mathrm{keV}$) X-ray luminosity function (HXLF) of $0.5-2\,\mathrm{keV}$ band selected AGN at high redshift. We have assembled a sample of 141 AGN at $3<z\lesssim5$ from X-ray surveys of different size and depth, in order to sample different regions in the $L_X - z$ plane. The HXLF is fitted in the range $\mathrm{logL_X\sim43-45}$ with standard analytical evolutionary models through a maximum likelihood procedure. The evolution of the HXLF is well described by a pure density evolution, with the AGN space density declining by a factor of $\sim10$ from $z=3$ to 5. A luminosity-dependent density evolution model which, normally, best represents the HXLF evolution at lower redshift, is also consistent with the data, but a larger sample of low-luminosity ($\mathrm{logL_X}<44$), high-redshift AGN is necessary to constrain this model. We also estimated the intrinsic fraction of AGN obscured by a column density $\mathrm{logN_H}\geq23$ to be $0.54\pm0.05$, with no strong dependence on luminosity. This fraction is higher than the value in the Local Universe, suggesting an evolution of the luminous ($\mathrm{L_X>10^{44}\mathrm{erg\,s^{-1}}}$) obscured AGN fraction from $z=0$ to $z>3$.Comment: MNRAS, Accepted 2014 September 23. Received 2014 September 10; in original form 2014 August 5; 19 pages, 11 figures, 5 table

When home and work are not enough. The challenge of international migrants’ agency in the Italian Alps

Even when they have access to housing and employment, international migrants struggle to develop their own agency, i.e. the capacity to act in their own life contexts, exercising citizenship rights within substantive inclusion processes in the wider communities. The territorial context in fact, especially in rural and mountainous areas such as the Alpine ones analysed here, seems in many ways to represent a limit to the development of capacities and exercise of rights. Difficulties in accessing public space and public sphere, scarce social recognition, low status, housing isolation (as is the case of those who live in small mountain villages), professional ghettoisation: these are factors that, even in presence of an acceptable working and housing inclusion, make it difficult for international migrants to exercise their rights, to have their skills recognised, and, ultimately, to develop an agency genuinely linked to their capabilities. In this article, with reference to the action-research activities carried out in 2020-22 by the Horizon2020 MATILDE project in the Italian Alpine areas of South Tyrol and the Metropolitan City of Turin, attention is focused on the policies that could favour the effective migrants’ agency in mountain territories

When home and work are not enough. The challenge of international migrants’ agency in the Italian Alps

Even when they have access to housing and employment, international migrants struggle to develop their own agency, i.e. the capacity to act in their own life contexts, exercising citizenship rights within substantive inclusion processes in the wider communities. The territorial context in fact, especially in rural and mountainous areas such as the Alpine ones analysed here, seems in many ways to represent a limit to the development of capacities and exercise of rights. Difficulties in accessing public space and public sphere, scarce social recognition, low status, housing isolation (as is the case of those who live in small mountain villages), professional ghettoisation: these are factors that, even in presence of an acceptable working and housing inclusion, make it difficult for international migrants to exercise their rights, to have their skills recognised, and, ultimately, to develop an agency genuinely linked to their capabilities. In this article, with reference to the action-research activities carried out in 2020-22 by the Horizon2020 MATILDE project in the Italian Alpine areas of South Tyrol and the Metropolitan City of Turin, attention is focused on the policies that could favour the effective migrants’ agency in mountain territories