Obscured and unobscured AGN populations in a hard-X-ray selected sample of the XMDS survey

Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample of 136 X-ray sources in the XMM Medium Deep Survey (XMDS) with wide multiwavelength coverage. The XMDS area is covered with optical photometry from the VVDS and CFHTLS surveys and infrared Spitzer data. Based on the X-ray luminosity and X-ray to optical ratio, 132 sources are likely AGN, of which 122 have unambiguous optical - IR identification. The observed optical and IR spectral energy distributions of sources are fitted with AGN/galaxy templates in order to classify them and compute photometric redshifts. 70% of the AGN are fitted by a type 2 AGN or a star forming galaxy template and are grouped together in a single class of ``optically obscured'' AGN. They have ``red'' optical colors and generally show significant X-ray absorption from X-ray spectra or hardness ratios (N$_H > 10^{22}$ cm$^{-2}$). Sources with SEDs typical of type 1 AGN have ``blue'' optical colors and exhibit X-ray absorption in about 30% of cases. We performed a stacking analysis for obscured and type 1 AGN. The stacked X-ray spectrum of obscured AGN is flatter than that of type 1 AGN and has an average spectral slope of Gamma = 1.6. The subsample of objects fitted by a galaxy template has an even harder stacked spectrum, with Gamma = 1.2 - 1.3. The obscured fraction is larger at lower fluxes, lower redshifts and lower luminosities. X-ray absorption is less common than ``optical'' obscuration and its incidence is nearly constant with redshift and luminosity. This implies that X-ray absorption is not necessarily related to optical obscuration.Comment: 33 pages, 21 figures, accepted for publication in A&

Mobile phone text messaging to improve medication adherence in secondary prevention of cardiovascular disease.

BACKGROUND: Worldwide at least 100 million people are thought to have prevalent cardiovascular disease (CVD). This population has a five times greater chance of suffering a recurrent cardiovascular event than people without known CVD. Secondary CVD prevention is defined as action aimed to reduce the probability of recurrence of such events. Drug interventions have been shown to be cost-effective in reducing this risk and are recommended in international guidelines. However, adherence to recommended treatments remains sub-optimal. In order to influence non-adherence, there is a need to develop scalable and cost-effective behaviour-change interventions. OBJECTIVES: To assess the effects of mobile phone text messaging in patients with established arterial occlusive events on adherence to treatment, fatal and non-fatal cardiovascular events, and adverse effects. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, the Conference Proceedings Citation Index - Science on Web of Science on 7 November 2016, and two clinical trial registers on 12 November 2016. We contacted authors of included studies for missing information and searched reference lists of relevant papers. We applied no language or date restrictions. SELECTION CRITERIA: We included randomised trials with at least 50% of the participants with established arterial occlusive events. We included trials investigating interventions using short message service (SMS) or multimedia messaging service (MMS) with the aim to improve adherence to medication for the secondary prevention of cardiovascular events. Eligible comparators were no intervention or other modes of communication. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. In addition, we attempted to contact all authors on how the SMS were developed. MAIN RESULTS: We included seven trials (reported in 13 reports) with 1310 participants randomised. Follow-up ranged from one month to 12 months. Due to heterogeneity in the methods, population and outcome measures, we were unable to conduct meta-analysis on these studies. All seven studies reported on adherence, but using different methods and scales. Six out of seven trials showed a beneficial effect of mobile phone text messaging for medication adherence. Dale 2015a, reported significantly greater medication adherence score in the intervention group (Mean Difference (MD) 0.58, 95% confidence interval (CI) 0.19 to 0.97; 123 participants randomised) at six months. Khonsari 2015 reported less adherence in the control group (Relative Risk (RR) 4.09, 95% CI 1.82 to 9.18; 62 participants randomised) at eight weeks. Pandey 2014 (34 participants randomised) assessed medication adherence through self-reported logs with 90% adherence in the intervention group compared to 70% in the control group at 12 months. Park 2014a (90 participants randomised) reported a greater increase of the medication adherence score in the control group, but also measured adherence with an event monitoring system for a number of medications with adherence levels ranging from 84.1% adherence to 86.2% in the intervention group and 79.7% to 85.7% in the control group at 30 days. Quilici 2013, reported reduced odds of non-adherence in the intervention group (Odds Ratio (OR) 0.43, 95% CI 0.22 to 0.86, 521 participants randomised) at 30 days. Fang 2016, reported that participants given SMS alone had reduced odds of being non-adherent compared to telephone reminders (OR 0.40 95% CI 0.18 to 0.63; 280 patients randomised). Kamal 2015 reported higher levels of adherence in the intervention arm (adjusted MD 0.54, 95% CI 0.22 to 0.85; 200 participants randomised). Khonsari 2015 was the only study to report fatal cardiovascular events and only reported two events, both in the control arm. No study reported on the other primary outcomes. No study reported repetitive thumb injury or road traffic crashes or other adverse events that were related to the intervention.Four authors replied to our questionnaire on SMS development. No study reported examining causes of non-adherence or provided SMS tailored to individual patient characteristics.The included studies were small, heterogeneous and included participants recruited directly after acute events. All studies were assessed as having high risk of bias across at least one domain. Most of the studies came from high-income countries, with two studies conducted in an upper middle-income country (China, Malaysia), and one study from a lower middle-income country (Pakistan). The quality of the evidence was found to be very low. There was no obvious conflicts of interest from authors, although only two declared their funding. AUTHORS' CONCLUSIONS: While the results of this systematic review are promising, there is insufficient evidence to draw conclusions on the effectiveness of text message-based interventions for adherence to medications for secondary prevention of CVD. Sufficiently powered, high-quality randomised trials are needed, particularly in low- and middle-income countries

Spectral Energy Distributions of Hard X-ray selected AGNs in the XMDS Survey

We present the spectral energy distributions (SEDs) of a hard X-ray selected sample. The sample contains 136 sources with F(2-10 keV)>10^-14 erg/cm^2/s and 132 are AGNs. The sources are detected in a 1 square degree area of the XMM-Newton-Medium Deep Survey where optical data from the VVDS, CFHTLS surveys, and infrared data from the SWIRE survey are available. Based on a SED fitting technique we derive photometric redshifts with sigma(1+z)=0.11 and 6% of outliers and identify AGN signatures in 83% of the objects. This fraction is higher than derived when a spectroscopic classification is available. The remaining 17+9-6% of AGNs shows star-forming galaxy SEDs (SF class). The sources with AGN signatures are divided in two classes, AGN1 (33+6-1%) and AGN2 (50+6-11). The AGN1 and AGN2 classes include sources whose SEDs are fitted by type 1 and type 2 AGN templates, respectively. On average, AGN1s show soft X-ray spectra, consistent with being unabsorbed, while AGN2s and SFs show hard X-ray spectra, consistent with being absorbed. The analysis of the average SEDs as a function of X-ray luminosity shows a reddening of the IR SEDs, consistent with a decreasing contribution from the host galaxy at higher luminosities. The AGNs in the SF classes are likely obscured in the mid-infrared, as suggested by their low L(3-20micron)/Lcorr(0.5-10 keV) ratios. We confirm the previously found correlation for AGNs between the radio luminosity and the X-ray and the mid-infrared luminosities. The X-ray-radio correlation can be used to identify heavily absorbed AGNs. However, the estimated radio fluxes for the missing AGN population responsible for the bulk of the background at E>10 keV are too faint to be detected even in the deepest current radio surveys.Comment: Accepted for publication in Ap

The XMM-LSS survey: The XMDS/VVDS 4 sigma catalogue

We present a first catalogue of X-ray sources resulting from the central area of the XMM-LSS (Large Scale Structure survey). We describe the reduction procedures and the database tools we developed and used to derive a well defined catalogue of X-ray sources. The present catalogue is limited to a sub-sample of 286 sources detected at 4 sigma in the 1 deg^2 area covered by the photometric VVDS (VIRMOS VLT Deep Survey), which allows us to provide optical and radio identifications. We also discuss the X-ray properties of a larger X-ray sample of 536 sources detected at > 4 sigma in the full 3 deg^2 area of the XMM Medium Deep Survey (XMDS) independently of the optical identification. We also derive the logN-logS relationship for a sample of more than one thousand sources that we discuss in the context of other surveys at similar fluxes.Comment: 15+6 pages, 12 figures, accepted for publication in Astronomy & Astrophysics The online catalogue announced in the paper will be accessible in about 2 weeks due to technical reasons Fig. 2 replaced with a low resolution on

The XMM large scale structure survey: optical vs. X-ray classifications of active galactic nuclei and the unified scheme

Our goal is to characterize AGN populations by comparing their X-ray and optical classifications. We present a sample of 99 spectroscopically identified X-ray point sources in the XMM-LSS survey which are significantly detected in the [2-10] keV band, and with more than 80 counts. We performed an X-ray spectral analysis for all of these 99 X-ray sources. Introducing the fourfold point correlation coefficient, we find only a mild correlation between the X-ray and the optical classifications, as up to 30% of the sources have differing X-ray and optical classifications: on one hand, 10% of the type 1 sources present broad emission lines in their optical spectra and strong absorption in the X-rays. These objects are highly luminous AGN lying at high redshift and thus dilution effects are totally ruled out, their discrepant nature being an intrinsic property. Their X-ray luminosities and redshifts distributions are consistent with those of the unabsorbed X-ray sources with broad emission lines. On the other hand, 25/32 are moderate luminosity AGN, which are both unabsorbed in the X-rays and only present narrow emission lines in their optical spectra. The majority of them have an optical spectrum which is representative of the host galaxy. We finally infer that dilution of the AGN by the host galaxy seems to account for their nature. 5/25 have been defined as Seyfert 2. In conclusion, most of these 32 discrepant cases can be accounted for by the standard AGN unified scheme, as its predictions are not met for only 12% of the 99 X-ray sources. ABRIDGEDComment: 25 pages, 19 figures, Accepted for publication in A&

A multi-wavelength survey of AGN in the XMM-LSS field: I. Quasar selection via the KX technique

AIMS: We present a sample of candidate quasars selected using the KX-technique. The data cover 0.68 deg^2 of the X-ray Multi-Mirror (XMM) Large-Scale Structure (LSS) survey area where overlapping multi-wavelength imaging data permits an investigation of the physical nature of selected sources. METHODS: The KX method identifies quasars on the basis of their optical (R and z') to near-infrared (Ks) photometry and point-like morphology. We combine these data with optical (u*,g'r',i',z') and mid-infrared (3.6-24 micron) wavebands to reconstruct the spectral energy distributions (SEDs) of candidate quasars. RESULTS: Of 93 sources selected as candidate quasars by the KX method, 25 are classified as quasars by the subsequent SED analysis. Spectroscopic observations are available for 12/25 of these sources and confirm the quasar hypothesis in each case. Even more, 90% of the SED-classified quasars show X-ray emission, a property not shared by any of the false candidates in the KX-selected sample. Applying a photometric redshift analysis to the sources without spectroscopy indicates that the 25 sources classified as quasars occupy the interval 0.7 < z < 2.5. The remaining 68/93 sources are classified as stars and unresolved galaxies.Comment: 13 pages, 9 figures, A&A 494, p. 579-589. Replaced with published version. Fig. 9 in first astro-ph submission has been update

Mergers, AGN, and 'Normal' Galaxies: Contributions to the Distribution of Star Formation Rates and Infrared Luminosity Functions

We use a novel method to predict the contribution of normal star-forming galaxies, merger-induced bursts, and obscured AGN, to IR luminosity functions (LFs) and global SFR densities. We use empirical halo occupation constraints to populate halos with galaxies and determine the distribution of normal and merging galaxies. Each system can then be associated with high-resolution hydrodynamic simulations. We predict the distribution of observed luminosities and SFRs, from different galaxy classes, as a function of redshift from z=0-6. We provide fitting functions for the predicted LFs, quantify the uncertainties, and compare with observations. At all redshifts, 'normal' galaxies dominate the LF at moderate luminosities ~L* (the 'knee'). Merger-induced bursts increasingly dominate at L>>L*; at the most extreme luminosities, AGN are important. However, all populations increase in luminosity at higher redshifts, owing to increasing gas fractions. Thus the 'transition' between normal and merger-dominated sources increases from the LIRG-ULIRG threshold at z~0 to bright Hyper-LIRG thresholds at z~2. The transition to dominance by obscured AGN evolves similarly, at factor of several higher L_IR. At all redshifts, non-merging systems dominate the total luminosity/SFR density, with merger-induced bursts constituting ~5-10% and AGN ~1-5%. Bursts contribute little to scatter in the SFR-stellar mass relation. In fact, many systems identified as 'ongoing' mergers will be forming stars in their 'normal' (non-burst) mode. Counting this as 'merger-induced' star formation leads to a stronger apparent redshift evolution in the contribution of mergers to the SFR density.Comment: 16 pages, 9 figures (+appendices), accepted to MNRAS. A routine to return the galaxy merger rates discussed here is available at http://www.cfa.harvard.edu/~phopkins/Site/mergercalc.htm