GALEX measurements of the Big Blue Bump as a tool to study bolometric corrections in AGNs

Active Galactic Nuclei emit over the entire electromagnetic spectrum with the peak of the accretion disk emission in the far-UV, a wavelength range historically difficult to investigate. We use here the GALEX (Galaxy Evolution Explorer) Near-UV and Far-UV measurements (complemented with optical data from Sloan Digital Sky Survey (SDSS) and XMM-Newton X-ray spectra) of a sample of 83 X-ray selected type 1 AGN extracted from the XMM-Newton Bright Serendipitous Survey to study their spectral energy distribution (SED) in the optical, Near and Far-UV and X-ray energy bands. We have constrained the luminosity of the accretion disk emission component and calculated the hard X-ray bolometric corrections for a significant sample of AGN spanning a large range in properties (z, L(x)).Comment: 2 pages, 2 figures, To appear in refereed Proceedings of "X-ray Astronomy 2009: Present Status, Multi-Wavelength Approach and Future Perspectives", Bologna, Italy, September 7-11, 2009, AIP, eds. A. Comastri, M. Cappi, and L. Angelin

An integrated approach to prevent and treat respiratory failure in brain-injured patients

PURPOSE OF REVIEW: Brain-injured patients are at increased risk of extracerebral organ dysfunction, in particular ventilator-associated pneumonia. The purpose of this review is to discuss functional abnormalities, clinical treatment, and possible prevention of respiratory function abnormalities in brain-injured patients. RECENT FINDINGS: Ventilator-associated pneumonia worsens the neurologic outcome and increases the intensive care unit and hospital stay, costs, and risk of death. The respiratory dysfunction can be due to several causes, but atelectasis and/or consolidation of the lower lobes predominates in the most severe cases. Strategies should be implemented to prevent lung infections and accelerate weaning from mechanical ventilation to reduce the incidence of respiratory dysfunction and ventilator-associated pneumonia. SUMMARY: An integrated approach including appropriate ventilatory, antibiotic, and fluid management could be extremely useful, not only to prevent and more rapidly treat respiratory failure but also to improve neurologic outcome and reduce hospital stay. Further studies are warranted to better elucidate the pathophysiology and clinical treatment of respiratory dysfunction in brain-injured patients

Black-hole masses of type 1 AGN in the XMM-Newton bright serendipitous survey

We derive masses of the central super-massive black hole (SMBH) and accretion rates for 154 type1 AGN belonging to a well-defined X-ray-selected sample, the XMM-Newton Serendipitous Sample (XBS). To this end, we use the most recent "single-epoch" relations, based on Hbeta and MgII2798A emission lines, to derive the SMBH masses. We then use the bolometric luminosities, computed on the basis of an SED-fitting procedure, to calculate the accretion rates, both absolute and normalized to the Eddington luminosity (Eddington ratio). The selected AGNs cover a range of masses from 10^7 to 10^10 Msun with a peak around 8x10^8 Msun and a range of accretion rates from 0.01 to ~50 Msun/year (assuming an efficiency of 0.1), with a peak at ~1 Msun/year. The values of Eddington ratio range from 0.001 to ~0.5 and peak at 0.1.Comment: 14 pages, 11 figures. Accepted for publication in Astronomy & Astrophysic

Heavily obscured AGN with SIMBOL-X

By comparing an optically selected sample of narrow lines AGN with an X-ray selected sample of AGN we have recently derived an estimate of the intrinsic (i.e. before absorption) 2-10 keV luminosity function (XLF) of Compton Thick AGNs. We will use this XLF to derive the number of Compton Thick AGN that will be found in the SIMBOL-X survey(s).Comment: Talk at the Simbol-X symposium held in Paris, 2-5 December, 2008. 6 pages, 1 figure with three panel

The relationship between [OIII]5007A equivalent width and obscuration in AGN

In this paper we study the relationship between the equivalent width (EW) of the [OIII]5007A narrow emission line in AGN and the level of obscuration. To this end, we combine the results of a systematic spectral analysis, both in the optical and in the X-rays, on a statistically complete sample of ~170 X-ray selected AGN from the XMM-Newton Bright Serendipitous Source sample (XBS). We find that the observed large range of [OIII]5007A equivalent widths observed in the sample (from a few A up to 500A) is well explained as a combination of an intrinsic spread, probably due to the large range of covering factors of the Narrow Line Region, and the effect of absorption. The intrinsic spread is dominant for EW below 40-50A while absorption brings the values of EW up to ~100-150A, for moderate levels of absorption (AV~0.5-2 mag) or up to ~500A for AV>2 mag. In this picture, the absorption has a significant impact on the observed EW also in type~1 AGN. Using numerical simulations we find that this model is able to reproduce the [OIII]5007A EW distribution observed in the XBS sample and correctly predicts the shape of the EW distribution observed in the optically selected sample of QSO taken from the SDSS survey.Comment: 7 pages, 5 figures. Accepted for publication in MNRA

An Hα_\alpha Catalogue of Galaxies in Hickson Compact Groups. I. The Sample

We present H$_\alpha$ photometry for a sample of 95 galaxies in Hickson Compact Groups obtained from observations of 31 groups. The Catalogue lists isophotal and adaptive aperture (Kron aperture) flux measurements for about 75% of the accordant galaxies inside the observed HCGs, 22 out of which are upper limits. Non standard data reduction procedures have been used to obtain the continuum subtracted H$_\alpha$ images for each HCG of the target sample. Flux calibration has also been performed in order to obtain H$_\alpha$ luminosities for the whole sample. Both the data reduction and calibration procedures are carefully described in this paper. The new data listed in this Catalogue are of great importance in understanding the star formation rate inside HCG galaxies and in giving new insights on its dependence on galaxy interactions.Comment: Accepted for publication in A&AS, 22 pages, including 23 figure

The Kormendy relation of massive elliptical galaxies at z~1.5. Evidence for size evolution ?

We present the morphological analysis based on HST-NIC2 (0.075 arcsec/pixel) images in the F160W filter of a sample of 9 massive field (> 10^{11} M_\odot) galaxies spectroscopically classified as early-types at 1.2<z<1.7. Our analysis shows that all of them are bulge dominated systems. In particular, 6 of them are well fitted by a de Vaucouleurs profile (n=4) suggesting that they can be considered pure elliptical galaxies. The remaining 3 galaxies are better fitted by a Sersic profile with index 1.9<n<2.3 suggesting that a disk-like component could contribute up to 30% to the total light of these galaxies. We derived the effective radius R_e and the mean surface brightness within R_e of our galaxies and we compared them with those of early-types at lower redshifts. We find that the surface brightness of our galaxies should get fainter by 2.5 mag from z~1.5 to z~0 to match the surface brightness of the local ellipticals with comparable R_e, i.e. the local Kormendy relation. Luminosity evolution without morphological changes can only explain half of this effect, as the maximum dimming expected for an elliptical galaxy is ~1.6 mag in this redshift range. Thus, other parameters, possibly structural, may undergo evolution and play an important role in reconciling models and observations. Hypothesizing an evolution of the effective radius of galaxies we find that R_e should increase by a factor 1.5 from z~1.5 to z~0.Comment: Accepted for publication in MNRAS, 15 pages, 8 figure