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PSR J1357-6429 is a young radio pulsar that has been detected in the X-ray and γ -ray bands. We present high spatial resolution near-infrared imaging of the pulsar field in the J, H and Ks bands obtained using the VLT/NaCo with the Adaptive Optic system. We found a faint source at the most precise pulsar radio position, which we propose as the pulsar near-infrared counterpart candidate. It is confidently detected in the J and Ks bands, with J=23.51±0.24 and Ks =21.82±0.25. There is a hint of the source in theHband, with an upper limitH>22.8. The dereddened source fluxes are compatible with the extrapolation of the pulsar X-ray spectrum towards the near-infrared. If the candidate is the true counterpart, this property means that PSR J1357-6429 would be similar to the nearby middle-age pulsar PSR B0656+14. In this case, both pulsars demonstrate an unusually high near-infrared efficiency relative to the X-ray efficiency as compared with other pulsars detected in these two ranges. [ABSTRACT FROM AUTHOR]

Dust grains scatter X-ray light through small angles, producing a diffuse halo image around bright X-ray point sources situated behind a large amount of interstellar material. We present analytic solutions to the integral for the dust scattering intensity, which allow for a Bayesian analysis of the scattering halo around Cygnus X-3. Fitting the optically thin 4-6 keV halo surface brightness profile yields the dust grain size and spatial distribution. We assume a power-law distribution of grain sizes (n α a--p) and fit for p, the grain radius cut-off amax, and dust mass column. We find that ap ≈ 3.5 dust grain size distribution with amax ≈ 0.2 μm fits the halo profile relatively well, whether the dust is distributed uniformly along the line of sight or in clumps. We find that a model consisting of two dust screens, representative of foreground spiral arms, requires the foreground Perseus arm to contain 80 per cent of the total dust mass. The remaining 20 per cent of the dust, which may be associated with the outer spiral arm of the Milky Way, is located within 1 kpc of Cyg X-3. Regardless of which model was used, we found tsca ~ 2 EkeV-2. We examine the energy resolved haloes of Cyg X-3 from 1 to 6 keV and find that there is a sharp drop in scattering halo intensity when E < 2-3 keV, which cannot be explained with multiple scattering effects. We hypothesize that this may be caused by large dust grains or material with unique dielectric properties, causing the scattering cross-section to depart from the Rayleigh-Gans approximation that is used most often in X-ray scattering studies. The foreground Cyg OB2 association, which contains several evolved stars with large extinction values, is a likely culprit for grains of unique size or composition. [ABSTRACT FROM AUTHOR]

One of the major sources of the X-ray emitting hot gas around galaxies is the feedback from supernovae (SNe), but most of this metal-enriched feedback material is often not directly detected in X-ray observations. This missing galactic feedback problem is extremely prominent in early-type galaxy bulges, where there is little cool gas to make the Type Ia SNe ejecta radiate at lower temperature beyond the X-ray domain. We herein present a deep Suzaku observation of an S0 galaxy NGC 5866, which is relatively rich in molecular gas as an S0 galaxy and shows significant evidence of cool-hot gas interaction. By jointly analysing the Suzaku and an archival Chandra data, we measure the Fe/O abundance ratio to be 7.63+7.28-5.52 relative to solar values. This abundance ratio is much higher than those of spiral galaxies, and even among the highest ones of S0 and elliptical galaxies. NGC 5866 also simultaneously has the highest Fe/O abundance ratio and molecular gas mass among a small sample of gas-poor early-type galaxies. An estimation of the Fe budget indicates that NGC 5866 could preserve a larger than usual fraction, but far from the total amount of Fe injected by Type Ia SNe. We also find that the hot gas temperature increases from inner to outer haloes, with the inner region has a temperature of ~0.25 keV, clearly lower than that expected from Type Ia SNe heating. This low temperature could be most naturally explained by additional cooling processes related to the cool-hot gas interaction as being indicated by the existence of many extraplanar dusty filaments. Our results indicate that the large cool gas content and the presence of cool-hot gas interaction in the inner region of NGC 5866 have significantly reduced the specific energy of the SN ejecta and so the velocity of the galactic outflow. The galaxy could thus preserve a considerable fraction of the metal-enriched feedback material from being blown out. [ABSTRACT FROM AUTHOR]

In this study, we investigate the relationship between the star formation rate (SFR) and AGN luminosity (LAGN) for ~2000 X-ray detected AGN. The AGN span over three orders of magnitude in X-ray luminosity (1042 < L2-8keV < 1045.5 erg s-1) and are in the redshift range z = 0.2-2.5. Using infrared (IR) photometry (8-500 μm), including deblended Spitzer and Herschel images and taking into account photometric upper limits, we decompose the IR spectral energy distributions into AGN and star formation components. Using the IR luminosities due to star formation, we investigate the average SFRs as a function of redshift and AGN luminosity. In agreement with previous studies, we find a strong evolution of the average SFR with redshift, tracking the observed evolution of the overall star-forming galaxy population. However, we find that the relationship between the average SFR and AGN luminosity is broadly flat at all redshifts and across all the AGN luminosities investigated; in comparison to previous studies, we find less scatter amongst the average SFRs across the wide range of AGN luminosities investigated. By comparing to empirical models, we argue that the observed flat relationship is due to short time-scale variations in AGN luminosity, driven by changes in the mass accretion rate, which wash out any underlying correlations between SFR and LAGN. Furthermore, we show that the exact form of the predicted relationship between SFR and AGN luminosity (and its normalization) is highly sensitive to the assumed intrinsic Eddington ratio distribution. [ABSTRACT FROM AUTHOR]

We present X-shooter at Very Large Telescope observations of a sample of 10 luminous, X-ray obscured quasi-stellar objects (QSOs) at z ~ 1.5 from the XMM-COSMOS survey, expected to be caught in the transitioning phase from starburst to active galactic nucleus (AGN)-dominated systems. The main selection criterion is X-ray detection at bright fluxes (LX 1044 erg s-1) coupled to red optical-to-near-infrared-to-mid-infrared colours. Thanks to its large wavelength coverage, X-shooter allowed us to determine accurate redshifts from the presence of multiple emission lines for five out of six targets for which we had only a photometric redshift estimate, with an 80 per cent success rate, significantly larger than what is observed in similar programs of spectroscopic follow-up of red QSOs. We report the detection of broad and shifted components in the [OIII] ƛƛ5007, 4959 complexes for six out of eight sources with these lines observable in regions free from strong atmospheric absorptions. The full width at half-maximum (FWHM) associated with the broad components are in the range FWHM ~ 900-1600 km s-1, larger than the average value observed in Sloan Digital Sky Survey type 2 AGN samples at similar observed [OIII] luminosity, but comparable to those observed for QSO/ultraluminous infrared galaxies systems for which the presence of kpc scale outflows has been revealed through integral field unit spectroscopy. Although the total outflow energetics (inferred under reasonable assumptions) may be consistent with winds accelerated by stellar processes, we favour an AGN origin for the outflows given the high outflow velocities observed (v > 1000 km s-1) and the presence of strong winds also in objects undetected in the far-infrared. [ABSTRACT FROM AUTHOR]

We present a large-scale study of the X-ray properties and near-IR-to-radio spectral energy distributions (SEDs) of submillimetre galaxies (SMGs) detected at 1.1 mm with the AzTEC instrument across a ∼1.2 square degree area of the sky. Combining deep 2–4 Ms Chandra data with Spitzer IRAC/MIPS and Very Large Array data within the Great Observatories Origins Deep Survey North (GOODS-N), GOODS-S and COSMOS fields, we find evidence for active galactic nucleus (AGN) activity in ∼14 per cent of 271 AzTEC SMGs, ∼28 per cent considering only the two GOODS fields. Through X-ray spectral modelling and multiwavelength SED fitting using Monte Carlo Markov chain techniques to Siebenmorgen et al. (AGN) and Efstathiou, Rowan-Robinson & Siebenmorgen (starburst) templates, we find that while star formation dominates the IR emission, with star formation rates (SFRs) ∼100–1000 M⊙ yr−1, the X-ray emission for most sources is almost exclusively from obscured AGNs, with column densities in excess of 1023 cm−2. Only for ∼6 per cent of our sources do we find an X-ray-derived SFR consistent with NIR-to-radio SED derived SFRs. Inclusion of the X-ray luminosities as a prior to the NIR-to-radio SED effectively sets the AGN luminosity and SFR, preventing significant contribution from the AGN template. Our SED modelling further shows that the AGN and starburst templates typically lack the required 1.1 mm emission necessary to match observations, arguing for an extended, cool dust component. The cross-correlation function between the full samples of X-ray sources and SMGs in these fields does not indicate a strong correlation between the two populations at large scales, suggesting that SMGs and AGNs do not necessarily trace the same underlying large-scale structure. Combined with the remaining X-ray-dim SMGs, this suggests that sub-mm-bright sources may evolve along multiple tracks, with X-ray-detected SMGs representing transitionary objects between periods of high star formation and AGN activity, while X-ray-faint SMGs represent a brief starburst phase of more normal galaxies. [ABSTRACT FROM AUTHOR]

Background: A CT scanner makes many measurements, from different rotational angles, of X-ray attenuation (weakening in force or intensity) through the cross-sectional plane of the thorax. It then uses these data to reconstruct a digital representation of the cross-section with each pixel of the image representing a measurement of the mean attenuation through the thickness of the predetermined segment. This measurement quantifies the fraction of radiation removed in passing through a given amount of material of a certain thickness. Objective: To compare the chest CT scan and chest x-ray for early detection of pulmonary complications for adults hospitalized in intensive care unit. Patients and Methods: In the present prospective study, we included 40 adults' patients, who were hospitalized in Intensive Care Unit (ICU), in order to compare the diagnostic accuracy of chest X-ray and CT scan for early detection of pulmonary complications. Patients were recruited from the ICUs of Ain Shams University and Misr University for Science and Technology Hospitals. They were included whether they had primary respiratory manifestations or started to develop respiratory manifestations during ICU stay. Results: In the present study, we included 10 patients who were diagnosed with pulmonary embolism. The mean age of the included patients was 59.7 ± 16.3 years old. Five patients were correctly identified by the chest X-ray. Thus, the chest X-ray sensitivity for the detection of pneumonia was 50% and the positive predictive value was 100%. Conclusion: In our cohort of patients with a wide variety of chest disorders, routine chest X-ray was not useful to clinicians in the diagnosis of lung disease, compared to chest CT. In addition, chest X-ray had a very low sensitivity in specific conditions like pulmonary embolism and pneumothorax. [ABSTRACT FROM AUTHOR]