Search

Using 190,000 spectra from the seventeenth data release of the Sloan Digital Sky Survey, we investigate the ultraviolet emission line properties in z=2 quasars. Specifically, we quantify how the shape of CIV 1549A and the equivalent width (EW) of HeII 1640A depend on the black hole mass and Eddington ratio inferred from MgII 2800A. Above L/L_Edd>0.2, there is a strong mass dependence in both CIV blueshift and HeII EW. Large CIV blueshifts are observed only in regions with both high mass and high accretion rate. Including X-ray measurements for a subsample of 5,000 objects, we interpret our observations in the context of AGN accretion and outflow mechanisms. The observed trends in HeII and 2 keV strength are broadly consistent with theoretical QSOSED models of AGN spectral energy distributions (SEDs) for low spin black holes, where the ionizing SED depends on the accretion disc temperature and the strength of the soft excess. High spin models are not consistent with observations, suggesting SDSS quasars at z=2 may in general have low spins. We find a dramatic switch in behaviour at L/L_Edd, Resubmitted to MNRAS. Minor edits to text; figures updated; licence updated

We construct a parametric SED model which is able to reproduce the average observed SDSS-UKIDSS-WISE quasar colours to within one tenth of a magnitude across a wide range of redshift $(0M_i>-29)$. This model is shown to provide accurate predictions for the colours of known quasars which are less luminous than those used to calibrate the model parameters, and also those at higher redshifts $z>5$. Using a single parameter, the model encapsulates an up-to-date understanding of the intra-population variance in the rest-frame ultraviolet and optical emission lines of luminous quasars. At fixed redshift, there are systematic changes in the average quasar colours with apparent i-band magnitude, which we find to be well explained by the contribution from the host galaxy and our parametrization of the emission-line properties. By including redshift as an additional free parameter, the model could be used to provide photometric redshifts for individual objects. For the population as a whole we find that the average emission line and host galaxy contributions can be well described by simple functions of luminosity which account for the observed changes in the average quasar colours across $18.1, Comment: 18 pages, 16 figures, accepted for publication in MNRAS. The model code is available at https://github.com/MJTemple/qsogen/

The flux ratios of high-ionization lines are commonly assumed to indicate the metallicity of the broad emission line region in luminous quasars. When accounting for the variation in their kinematic profiles, we show that the NV/CIV, (SiIV+OIV])/CIV and NV/Lya line ratios do not vary as a function of the quasar continuum luminosity, black hole mass, or accretion rate. Using photoionization models from CLOUDY , we further show that the observed changes in these line ratios can be explained by emission from gas with solar abundances, if the physical conditions of the emitting gas are allowed to vary over a broad range of densities and ionizing fluxes. The diversity of broad line emission in quasar spectra can be explained by a model with emission from two kinematically distinct regions, where the line ratios suggest that these regions have either very different metallicity or density. Both simplicity and current galaxy evolution models suggest that near-solar abundances, with parts of the spectrum forming in high-density clouds, are more likely. Within this paradigm, objects with stronger outflow signatures show stronger emission from gas which is denser and located closer to the ionizing source, at radii consistent with simulations of line-driven disc-winds. Studies using broad-line ratios to infer chemical enrichment histories should consider changes in density and ionizing flux before estimating metallicities., 12 pages, 7 figures, accepted for publication in MNRAS. The interactive version of Figs. 3 and 4 will be made available as supplementary online material with the journal, and will be available at https://people.ast.cam.ac.uk/~alr53/CIV_yvar/all_plots.html until August 2021

We present the results of a new, deeper, and complete search for high-redshift $6.56.5$ quasars in this field. Additional observations of the other 17 candidates, primarily DESI Legacy Survey photometry and ESO FORS2 spectroscopy, confirm that none is a quasar. This is the first complete sample from the VIKING survey, and we provide the computed selection function. We include a detailed comparison of the BMC method against two other selection methods: colour cuts and minimum-$\chi^2$ SED fitting. We find that: i) BMC produces eight times fewer false positives than colour cuts, while also reaching 0.3 mag. deeper, ii) the minimum-$\chi^2$ SED fitting method is extremely efficient but reaches 0.7 mag. less deep than the BMC method, and selects only one of the four known quasars. We show that BMC candidates, rejected because their photometric SEDs have high $\chi^2$ values, include bright examples of galaxies with very strong [OIII]$\lambda\lambda$4959,5007 emission in the $Y$ band, identified in fainter surveys by Matsuoka et al. This is a potential contaminant population in Euclid searches for faint $z>7$ quasars, not previously accounted for, and that requires better characterisation., Comment: Accepted for MNRAS

We present new 850$\mu$m SCUBA-2 observations for a sample of 19 heavily reddened Type-I quasars at redshifts $z\sim$2 with dust extinctions of A$_{\rm{V}} \simeq 2-6$ mag. Three of the 19 quasars are detected at $>$3$\sigma$ significance corresponding to an 850$\mu$m flux-limit of $\gtrsim$4.8 mJy. Assuming the 850$\mu$m flux is dominated by dust heating due to star formation, very high star formation rates (SFR) of $\sim$2500-4500 M$_\odot$ yr$^{-1}$ in the quasar host galaxies are inferred. Even when considering a large contribution to the 850$\mu$m flux from dust heated by the quasar itself, significant SFRs of $\sim$600-1500 M$_\odot$ yr$^{-1}$ are nevertheless inferred for two of the three detected quasars. We stack the remaining 16 heavily reddened quasars and derive an average 3$\sigma$ upper limit on the SFRs in these quasar host galaxies of $, Comment: 11 pages, 9 figures, MNRAS Accepted

We present the results of a multi-wavelength follow up campaign for the luminous nuclear transient Gaia16aax, which was first identified in January 2016. The transient is spatially consistent with the nucleus of an active galaxy at z=0.25, hosting a black hole of mass $\rm \sim6\times10^8M_\odot$. The nucleus brightened by more than 1 magnitude in the Gaia G-band over a timescale of less than one year, before fading back to its pre-outburst state over the following three years. The optical spectra of the source show broad Balmer lines similar to the ones present in a pre-outburst spectrum. During the outburst, the $\rm H\alpha$ and $\rm H\beta$ emission lines develop a secondary peak. We also report on the discovery of two transients with similar light curve evolution and spectra: Gaia16aka and Gaia16ajq. We consider possible scenarios to explain the observed outbursts. We exclude that the transient event could be caused by a microlensing event, variable dust absorption or a tidal encounter between a neutron star and a stellar mass black hole in the accretion disk. We consider variability in the accretion flow in the inner part of the disk, or a tidal disruption event of a star $\geq 1 M_{\odot}$ by a rapidly spinning supermassive black hole as the most plausible scenarios. We note that the similarity between the light curves of the three Gaia transients may be a function of the Gaia alerts selection criteria., Comment: 21 pages, 17 figure - accepted for publication in MNRAS main journal

Antenatal care (ANC) and facility delivery are essential maternal health services, but uptake remains low in north-western Nigeria. This study aimed to assess the psychosocial influences on pregnancy and childbirth behaviours in Nigeria. Data were from a cross-sectional population-based survey of randomly sampled women with a child under 2 years conducted in Kebbi, Sokoto and Zamfara states of north-western Nigeria in September 2019. Women were asked about their maternal health behaviours during their last pregnancy. Psychosocial metrics were developed using the Ideation Model of Strategic Communication and Behaviour Change. Predicted probabilities for visiting ANC four or more times (ANC4+) and giving birth in a facility were derived using mixed-effects logistic regression models adjusted for ideational and socio-demographic variables. Among the 3039 sample women, 23.6% (95% CI: 18.0–30.3%) attended ANC4+ times and 15.5% (95% CI: 11.8–20.1%) gave birth in a facility. Among women who did not attend ANC4+ times or have a facility-based delivery during their last pregnancy, the most commonly cited reasons for non-use were lack of perceived need (42% and 67%, respectively) and spousal opposition (25% and 27%, respectively). Women who knew any ANC benefit or the recommended number of ANC visits were 3.2 and 2.1 times more likely to attend ANC4+ times, respectively. Women who held positive views about health facilities for childbirth had 1.2 and 2.6 times higher likelihood of attending ANC4+ times and having a facility delivery, respectively, while women who believed ANC was only for sickness or pregnancy complications had a 17% lower likelihood of attending ANC4+ times. Self-efficacy and supportive spousal influence were also significantly associated with both outcomes. To improve pregnancy and childbirth practices in north-western Nigeria, Social and Behavioural Change programmes could address a range of psychosocial factors across cognitive, emotional and social domains which have been found in this study to be significantly associated with pregnancy and childbirth behaviours: raising knowledge and dispelling myths, building women’s confidence to access services, engaging spousal support in decision-making and improving perceived (and actual) maternal health services quality.

We discuss a probe of the contribution of wind-related shocks to the radio emission in otherwise radio-quiet quasars. Given 1) the non-linear correlation between UV and X-ray luminosity in quasars, 2) that such correlation leads to higher likelihood of radiation-line-driven winds in more luminous quasars, and 3) that luminous quasars are more abundant at high redshift, deep radio observations of high-redshift quasars are needed to probe potential contributions from accretion disk winds. We target a sample of 50 $z\simeq 1.65$ color-selected quasars that span the range of expected accretion disk wind properties as traced by broad CIV emission. 3-GHz observations with the Very Large Array to an rms of $\approx10\mu$Jy beam$^{-1}$ probe to star formation rates of $\approx400\,M_{\rm Sun}\,{\rm yr}^{-1}$, leading to 22 detections. Supplementing these pointed observations are survey data of 388 sources from the LOFAR Two-metre Sky Survey Data Release 1 that reach comparable depth (for a typical radio spectral index), where 123 sources are detected. These combined observations reveal a radio detection fraction that is a non-linear function of \civ\ emission-line properties and suggest that the data may require multiple origins of radio emission in radio-quiet quasars. We find evidence for radio emission from weak jets or coronae in radio-quiet quasars with low Eddingtion ratios, with either (or both) star formation and accretion disk winds playing an important role in optically luminous quasars and correlated with increasing Eddington ratio. Additional pointed radio observations are needed to fully establish the nature of radio emission in radio-quiet quasars., Comment: 21 pages, 7 figures, submitted to AAS journals

The orientation of the disk of material accreting onto supermassive black holes that power quasars is one of most important quantities that are needed to understand quasars -- both individually and in the ensemble average. We present a hypothesis for determining comparatively edge-on orientation in a subset of quasars (both radio loud and radio quiet). If confirmed, this orientation indicator could be applicable to individual quasars without reference to radio or X-ray data and could identify some 10-20% of quasars as being more edge-on than average, based only on moderate resolution and signal-to-noise spectroscopy covering the CIV 1549A emission feature. We present a test of said hypothesis using X-ray observations and identify additional data that are needed to confirm this hypothesis and calibrate the metric., 7 pages, 2 figures, accepted for publication in ApJL

While multiple studies have documented shifting educational gradients in HIV prevalence, less attention has been given to the effect of school participation and academic skills on infection during adolescence. Using the Malawi Schooling and Adolescent Study, a longitudinal survey that followed 2,649 young people aged 14–17 at baseline from 2007 to 2013, we estimate the effect of three education variables: school enrolment, grade attainment, and academic skills—numeracy and Chichewa literacy—on herpes simplex virus type 2 (HSV-2) and HIV incidence using interval-censored survival analysis. We find that grade attainment is significantly associated with lower rates of both HSV-2 and HIV among girls, and is negatively associated with HSV-2 but not HIV among boys. School enrolment and academic skills are not significantly associated with sexually transmitted infections (STIs) for boys or girls in our final models. Efforts to encourage school progression in high-prevalence settings in sub-Saharan Africa could well reduce, or at least postpone, acquisition of STIs.

To maximize the impact of Zika prevention programming efforts, a prioritization process for social and behavior change programming was developed based on a combination of research evidence and programmatic experience. Prioritized behaviors were: application of mosquito repellent, use of condoms, removing unintentional standing water, covering and scrubbing walls of water storage containers, seeking prenatal care, and seeking counseling on family planning if not planning to get pregnant., Since the 2015 Zika outbreak in Latin America and the Caribbean, a plethora of behavior change messages have been promoted to reduce Zika transmission. One year after the United States Agency for International Development (USAID) initiated its Zika response, more than 30 variants of preventive behaviors were being promoted. This situation challenged social and behavior change (SBC) programming efforts that require a coordinated response and agreed upon set of focus behaviors to be effective. To support USAID implementing partners in harmonizing prevention efforts to reduce Zika infection, we developed an evidence-based process to identify behaviors with the highest potential to reduce Zika infection and transmission. We compiled a full list of behaviors and selected the most promising for a full evidence review. The review included systematic keyword searches on Google Scholar, extraction of all relevant published articles on Aedes-borne diseases between 2012 and 2018, review of seminal papers, and review of gray literature. We examined articles to determine each behavior's potential effectiveness in preventing Zika transmission or reducing the Aedes aegypti population. We also developed assessment criteria to delineate the ease with which the target population could adopt each behavior, including: (1) required frequency; (2) feasibility of the behavior; and (3) accessibility and cost of the necessary materials in the setting. These behaviors were refined through a consensus-building process with USAID's Zika implementing partners, considering contextual factors. The resulting 7 evidence-based preventive behaviors have high potential to strengthen SBC programming's impact in USAID's Zika response: (1) apply mosquito repellent, (2) use condoms during pregnancy, (3) remove standing water, (4) cover water storage containers, (5) clean/remove mosquito eggs from water containers, (6) seek antenatal care, and (7) seek family planning counseling. This case study documents a flexible process that can be adapted to inform the prioritization of behaviors when there is limited evidence available, as during many emergency responses.

Background Early initiation of breastfeeding (EIBF) within the first hour of birth and exclusive breastfeeding (EBF) for the first six months of life are beneficial for child survival and long-term health. Yet breastfeeding rates remain sub-optimal in Northwestern Nigeria, and such practices are often influenced by complex psychosocial factors at cognitive, social and emotional levels. To understand these influences, we developed a set of breastfeeding-related ideational factors and quantitatively examined their relationship with EIBF and EBF practices. Methods A cross‐sectional population‐based survey was conducted in Kebbi, Sokoto, and Zamfara states from September through October 2019. A random sample of over 3000 women with at least one child under 2 years was obtained. Respondents were asked about their health behaviors including breastfeeding practices for their youngest child under 2 years. Breastfeeding-related ideations were developed using the Ideation Model of Strategic Communication and Behavior Change. Mixed-effects logistic regression models were used to derive predicted probabilities for EIBF and EBF while adjusting for ideations and socio-demographic variables. Results Among 3039 women with a child under 2 years of age, 42.1% (95% CI: 35.1% - 49.4%) practiced EIBF, while 37.5% (95% CI: 29.8% - 46.0%) out of 721 infants aged 0-5 months were exclusively breastfed. Women who knew that EIBF was protective on the health of the newborn had 7.9 and 7.0 percentage points (pp) higher likelihood of EIBF and EBF practices respectively. Women who believed colostrum was harmful both had 8.4 pp lower likelihood of EIBF and EBF practices. We found a higher likelihood of practicing EIBF (5.1 pp) and EBF (13.3 pp) among women who knew at least one benefit of breastfeeding. Knowledge of the appropriate time to introduce complementary feeding and having self-efficacy to practice EBF were positively associated with 11.2 pp and 13.1 pp increased likelihood of practicing EBF alone. Household wealth, maternal occupation and attending ANC4+ times were associated with EIBF, while health provider’s influence was associated with EBF. Conclusion Social and Behavior Change (SBC) programs should focus on improving women’s knowledge about breastfeeding and its benefits, dispelling myths around colostrum as bad milk, building women’s confidence to exclusively breastfeed, and improving antenatal care uptake to support breastfeeding promotion.

We present and publicly release (https://www.gclasshst.com) the first spatially resolved H$\alpha$ maps of star-forming cluster galaxies at $z\sim1$, made possible with the Wide Field Camera 3 (WFC3) G141 grism on the Hubble Space Telescope (HST). Using a similar but updated method to 3D-HST in the field environment, we stack the H$\alpha$ maps in bins of stellar mass, measure the half-light radius of the H$\alpha$ distribution and compare it to the stellar continuum. The ratio of the H$\alpha$ to stellar continuum half-light radius, $R[\mathrm{H}\alpha/\mathrm{C}]=\frac{R_{\mathrm{eff, H}\alpha}}{R_{\mathrm{eff, Cont}}}$, is smaller in the clusters by $(6\pm9)\%$, but statistically consistent within $1\sigma$ uncertainties. A negligible difference in $R[\mathrm{H}\alpha/\mathrm{C}]$ with environment is surprising, given the higher quenched fractions in the clusters relative to the field. We postulate that the combination of high quenched fractions and no change in $R[\mathrm{H}\alpha/\mathrm{C}]$ with environment can be reconciled if environmental quenching proceeds rapidly. We investigate this hypothesis by performing similar analysis on the spectroscopically-confirmed recently quenched cluster galaxies. 87% have H$\alpha$ detections, with star formation rates $8\pm1$ times lower than star-forming cluster galaxies of similar stellar mass. Importantly, these galaxies have a $R[\mathrm{H}\alpha/\mathrm{C}]$ that is $(81\pm8)\%$ smaller than coeval star-forming field galaxies at fixed stellar mass. This suggests the environmental quenching process occurred outside-in. We conclude that disk truncation due to ram-pressure stripping is occurring in cluster galaxies at $z\sim1$, but more rapidly and/or efficiently than in $z\lesssim0.5$ clusters, such that the effects on $R[\mathrm{H}\alpha/\mathrm{C}]$ become observable just after the cluster galaxy has recently quenched., Comment: 21 pages, 7 figures, Accepted for publication in ApJ

BackgroundAntenatal care (ANC) and facility delivery are essential maternal health services, but uptake remains low in northwestern Nigeria. To increase service use, social and behavior change (SBC) programs target psychosocial influences across cognitive, emotional and social domains including knowledge, beliefs, self-efficacy, and social norms. Yet there remains limited research that measures and quantitatively examines the role of psychosocial influences on pregnancy and childbirth behaviors in Nigeria or elsewhere. MethodsA cross-sectional population-based survey of randomly sampled women with a child under two years was conducted in Kebbi, Sokoto and Zamfara states of northwestern Nigeria in September 2019. Women were asked about maternal health behaviors during their last pregnancy. New psychosocial metrics were developed using the Ideation Model of Strategic Communication and Behavior Change. Predicted probabilities for visiting ANC four or more times (ANC4+) and giving birth in a facility were derived using mixed-effects logistic regression models adjusted for ideational and sociodemographic variables.ResultsAmong 3,039 women, 23.6% (95% CI: 18.0%-30.3%) attended ANC4+ times and 15.5% (95% CI: 11.8%-20.1%) gave birth in a facility. Among women who did not attend ANC4+ times or have a facility-based delivery during their last pregnancies, the most commonly cited reasons were lack of perceived need (42% and 67%, respectively) and spousal opposition (25% and 27%, respectively). Women who knew any ANC benefit or the recommended number of ANC visits were 3.2- and 2.1-times more likely to attend ANC4+ times. Women who held positive views about health facilities for childbirth had 1.2- and 2.6-times higher likelihood of attending ANC4+ times and facility delivery, while women who believed ANC was only for sickness or pregnancy complications had 17% lower likelihood of attending ANC4+ times. Self-efficacy and supportive spousal influence were also significantly associated with both outcomes.ConclusionsTo improve pregnancy and childbirth practices in northwestern Nigeria, programs should address a range of psychosocial factors – across cognitive, emotional and social domains – that were significantly associated with pregnancy and childbirth behaviors: raising knowledge and dispelling myths, building women’s confidence to access services, engaging spousal support in decision-making, and improving perceived (and actual) maternal health services quality.

Background Northwestern Nigeria faces a situation of high fertility and low contraceptive use, driven in large part by high-fertility norms, pro-natal cultural and religious beliefs, misconceptions about contraceptive methods, and gender inequalities. Social and behavior change (SBC) programs often try to shift drivers of high fertility through multiple channels including mass and social media, as well as community-level group, and interpersonal activities. This study seeks to assist SBC programs to better tailor their efforts by assessing the effects of intermediate determinants of contraceptive use/uptake and by demonstrating their potential impacts on contraceptive use, interpersonal communication with partners, and contraceptive approval. Methods Data for this study come from a cross-sectional household survey, conducted in the states of Kebbi, Sokoto and Zamfara in northwestern Nigeria in September 2019, involving 3000 women aged 15 to 49 years with a child under 2 years. Using an ideational framework of behavior that highlights psychosocial influences, mixed effects logistic regression analyses assess associations between ideational factors and family planning outcomes, and post-estimation simulations with regression coefficients model the magnitude of effects for these intermediate determinants. Results Knowledge, approval of family planning, and social influences, particularly from husbands, were all associated with improved family planning outcomes. Approval of family planning was critical – women who personally approve of family planning were nearly three times more likely to be currently using modern contraception and nearly six times more likely to intend to start use in the next 6 m. Husband’s influence was also critical. Women who had ever talked about family planning with their husbands were three times more likely both to be currently using modern contraception and to intend to start in the next 6 m. Conclusion SBC programs interested in improving family planning outcomes could potentially achieve large gains in contraceptive use—even without large-scale changes in socio-economic and health services factors—by designing and implementing effective SBC interventions that improve knowledge, encourage spousal/partner communication, and work towards increasing personal approval of family planning. Uncertainty about the time-order of influencers and outcomes however precludes inferences about the existence of causal relationships and the potential for impact from interventions.

Objective:Adolescent girls are at risk for both macro- and micronutrient deficiencies affecting growth, maternal and child health. This study assessed the impact of an adolescent-girl-tailored nutritional education curriculum on nutritional outcomes, including knowledge, dietary behaviour, anthropometry and anaemia.Design:A cluster-randomised evaluation was conducted with two study arms: girls in mentor-led weekly girls’ groups receiving sexual and reproductive health and life-skills training assigned to an age-appropriate nutritional curriculum and control girls in the weekly girls’ groups without the nutritional education. The primary analysis was intent-to-treat (ITT) generalised least squares regression. Secondary analysis using two-stage, instrumental-variables estimation was also conducted.Setting:The intervention and evaluation were conducted in urban and rural areas across four of ten provinces in Zambia.Participants:In total, 2660 girl adolescents aged 10–19 years were interviewed in 2013 (baseline) and annually through 2017.Results:ITT results indicate that exposure to the nutritional educational programme did not meaningfully change outcomes for adolescents or their children. Intervention adolescents were no more likely to correctly identify healthy foods (P = 0·51) or proper infant-feeding practices (P = 0·92); were no less likely to be stunted (P = 0·30) or underweight (P = 0·87) and no less likely to be anaemic (P = 0·38). Outcomes for children of intervention participants were not improved, including being breastfed (P = 0·42), stunted (P = 0·21), wasted (P = 0·77) or anaemic (P = 0·51).Conclusions:Even a high-quality nutritional educational intervention tailored to adolescents within an empowerment programme does not assure improved nutritional outcomes; adolescent preferences, resource control and household dynamics require consideration in the context of nutritional educational programmes.

Recent improvements to atomic energy-level data allow, for the first time, accurate predictions to be made for the Fe III line emission strengths in the spectra of luminous, $L_\text{bol}=10^{46}-10^{48}$ erg/s, Active Galactic Nuclei. The Fe III emitting gas must be primarily photoionized, consistent with observations of line reverberation. We use CLOUDY models exploring a wide range of parameter space, together with 26,500 rest-frame ultraviolet spectra from the Sloan Digital Sky Survey, to constrain the physical conditions of the line emitting gas. The observed Fe III emission is best accounted for by dense ($n_H=10^{14}$ cm$^{-3}$) gas which is microturbulent, leading to smaller line optical depths and fluorescent excitation. Such high density gas appears to be present in the central regions of the majority of luminous quasars. Using our favoured model, we present theoretical predictions for the relative strengths of the Fe III UV34 $\lambda\lambda$1895,1914,1926 multiplet. This multiplet is blended with the Si III] $\lambda$1892 and C III] $\lambda$1909 emission lines and an accurate subtraction of UV34 is essential when using these lines to infer information about the physics of the broad line region in quasars., Comment: 12 pages, 11 figures, plus appendices

Using data from SDSS, UKIDSS and WISE, we investigate the properties of the high-frequency cutoff to the infrared emission in $\simeq$5000 carefully selected luminous ($L_{bol} \simeq 10^{47}$) type 1 quasars. The strength of $\simeq$2 $\mu$m emission, corresponding to emission from the hottest (T>1200K) dust in the sublimation zone surrounding the central continuum source, is observed to correlate with the blueshift of the C IV $\lambda$1550 emission line. We therefore find that objects with stronger signatures of nuclear outflows tend to have a larger covering fraction of sublimation-temperature dust. When controlling for the observed outflow strength, the hot dust covering fraction does not vary significantly across our sample as a function of luminosity, black hole mass or Eddington fraction. The correlation between the hot dust and the C IV line blueshifts, together with the lack of correlation between the hot dust and other parameters, therefore provides evidence of a link between the properties of the broad emission line region and the infrared-emitting dusty regions in quasars., Comment: 11 pages, 6 figures, plus appendices. Accepted to MNRAS 10 Dec 2020

Using a sample of $\simeq$144,000 quasars from the Sloan Digital Sky Survey data release 14 we investigate the outflow properties, evident both in absorption and emission, of high-ionization Broad Absorption Line (BAL) and non-BAL quasars with redshifts 1.6 $\lesssim z \leq$ 3.5 and luminosities 45.3 $< \log_{10}(L_{bol}) < $ 48.2 erg s$^{-1}$. Key to the investigation is a continuum and emission-line reconstruction scheme, based on mean-field independent component analysis, that allows the kinematic properties of the CIV$\lambda$1550 emission line to be compared directly for both non-BAL and BAL quasars. CIV-emission blueshift and equivalent-width (EW) measurements are thus available for both populations. Comparisons of the emission-line and BAL-trough properties reveal strong systematic correlations between the emission and absorption properties. The dependence of quantitative outflow indicators on physical properties such as quasar luminosity and luminosity relative to Eddington-luminosity are also shown to be essentially identical for the BAL and non-BAL populations. There is an absence of BALs in quasars with the hardest spectral energy distributions (SEDs), revealed by the presence of strong HeII$\lambda$1640 emission, large CIV$\lambda$1550-emission EW and no measurable blueshift. In the remainder of the CIV-emission blueshift versus EW space, BAL and non-BAL quasars are present at all locations; for every BAL-quasar it is possible to identify non-BAL quasars with the same emission-line outflow properties and SED-hardness. The co-location of BAL and non-BAL quasars as a function of emission-line outflow and physical properties is the key result of our investigation, demonstrating that (high-ionization) BALs and non-BALs represent different views of the same underlying quasar population., Comment: 22 pages, 18 figures, plus Appendices. Minor changes to reflect published version in MNRAS

The extent to which skills acquired during schooling are retained after school-leaving in developing countries remains largely unknown. Using a longitudinal dataset of Malawian adolescents aged 14–17 attending school when first interviewed in 2007, we investigate whether literacy and numeracy skills at school leaving were retained several years after. We find a significant gender difference in skill level after school leaving for English skills, even after controlling for initial skill level and grade attainment, with females scoring lower than males. Although the gender difference in numeracy is not significant, females score lower than males after school leaving.

We present the first rest-frame UV population study of 17 heavily reddened, high-luminosity (E(B-V)$_{\rm{QSO}}\gtrsim$ 0.5; L$_{\rm{bol}}>$ 10$^{46}$ergs$^{-1}$) broad-line quasars at $1.5 < z < 2.7$. We combine the first year of deep, optical, ground-based observations from the Dark Energy Survey (DES) with the near infrared VISTA Hemisphere Survey (VHS) and UKIDSS Large Area Survey (ULAS) data, from which the reddened quasars were initially identified. We demonstrate that the significant dust reddening towards the quasar in our sample allows host galaxy emission to be detected at the rest-frame UV wavelengths probed by the DES photometry. By exploiting this reddening effect, we disentangle the quasar emission from that of the host galaxy via spectral energy distribution (SED) fitting. We find evidence for a relatively unobscured, star-forming host galaxy in at least ten quasars, with a further three quasars exhibiting emission consistent with either star formation or scattered light. From the rest-frame UV emission, we derive instantaneous, dust-corrected star formation rates (SFRs) in the range 25 < SFR$_{\rm{UV}}$ < 365 M$_{\odot}$yr$^{-1}$, with an average SFR$_{\rm{UV}}$ = 130 $\pm$ 95 M$_{\odot}$yr$^{-1}$. We find a broad correlation between SFR$_{\rm{UV}}$ and the bolometric quasar luminosity. Overall, our results show evidence for coeval star formation and black hole accretion occurring in luminous, reddened quasars at the peak epoch of galaxy formation., 21 pages, 8 figures, MNRAS Accepted

Pregnancy among adolescent girls in Zambia is a significant concern on its own and as a factor in school dropout and early marriage, with one-third of girls aged 15-19 having experienced pregnancy. Using qualitative and quantitative data from the Adolescent Girls Empowerment Program, we explore transactional sex as a driver of adolescent pregnancy. In qualitative interviews, transactional sex was repeatedly discussed as the main driver of pregnancy, as respondents indicated that when a girl feels that she "owes" a man sex, it prevents her from declining sex or using condoms. In addition, multivariate Cox proportional hazards models using four rounds of longitudinal data from a sample of unmarried and never pregnant adolescent girls (n=1,853) show that girls who have engaged in transactional sex face a hazard of first premarital pregnancy almost 30 percent greater than their peers who have not, independent of the effect of other risk-related sexual behaviors such as condom use and number of sexual partners. Identifying and understanding the role of transactional sex in adolescent pregnancy is important for designing effective curricula and programs that delay pregnancy, and highlights the importance of addressing access to economic resources in adolescent health outcomes.

We report the results from a search for z > 6.5 quasars using the Dark Energy Survey (DES) Year 3 dataset combined with the VISTA Hemisphere Survey (VHS) and WISE All-Sky Survey. Our photometric selection method is shown to be highly efficient in identifying clean samples of high-redshift quasars leading to spectroscopic confirmation of three new quasars - VDESJ 0244-5008 (z=6.724), VDESJ 0020-3653 (z=6.834) and VDESJ 0246-5219 (z=6.90) - which were selected as the highest priority candidates in the survey data without any need for additional follow-up observations. The new quasars span the full range in luminosity covered by other z>6.5 quasar samples (J AB = 20.2 to 21.3; M1450 = -25.6 to -26.6). We have obtained spectroscopic observations in the near infrared for VDESJ 0244-5008 and VDESJ 0020-3653 as well as our previously identified quasar, VDESJ 0224-4711 at z=6.50 from Reed et al. (2017). We use the near infrared spectra to derive virial black-hole masses from the full-width-half-maximum of the MgII line. These black-hole masses are ~ 1 - 2 x 10$^9$M$_\odot$. Combining with the bolometric luminosities of these quasars of L$_{\rm{bol}}\simeq$ 1 - 3 x 10$^{47}$implies that the Eddington ratios are high - $\simeq$0.6-1.1. We consider the C\textrm{\textsc{IV}} emission line properties of the sample and demonstrate that our high-redshift quasars do not have unusual C\textrm{\textsc{IV}} line properties when compared to carefully matched low-redshift samples. Our new DES+VHS $z>6.5$ quasars now add to the growing census of luminous, rapidly accreting supermassive black-holes seen well into the epoch of reionisation.

We present VLT-SINFONI near infra-red spectra of 26 new heavily reddened quasar candidates selected from the UKIDSS-LAS, VISTA VHS and VIKING imaging surveys. This new sample extends our reddened quasar search to both brighter and fainter luminosities. 25 of the 26 candidates are confirmed to be broad line quasars with redshifts $0.72$. We present the first comparison of the [OIII] line properties in high luminosity obscured quasars to a large sample of 111 unobscured quasars in the same luminosity and redshift range. Broad wings extending to velocities of 2500 km/s are seen in the [OIII] emission line profiles of our reddened quasars, suggesting that strong outflows are affecting the ionised gas kinematics. However, we find no significant difference between the kinematics of the [OIII] emission in reddened and unobscured quasars when the two samples are matched in luminosity and redshift. Our results are consistent with a model where quasar-driven outflows persist for some time after the obscuring dust has been cleared from along the line of sight. Assuming the amount of ionised gas in obscured and unobscured quasars is similar, we use the equivalent width distribution of the [OIII] emission to constrain the location of the obscuring dust in our reddened quasars. We find that the dust is most likely to be located on galactic scales, outside the [OIII] emitting region., Comment: 12 pages, 7 figures, plus Appendices. Accepted for publication in MNRAS

Background Adolescent girls in Zambia face risks and vulnerabilities that challenge their healthy development into young women: early marriage and childbearing, sexual and gender-based violence, unintended pregnancy and HIV. The Adolescent Girls Empowerment Program (AGEP) was designed to address these challenges by building girls’ social, health and economic assets in the short term and improving sexual behavior, early marriage, pregnancy and education in the longer term. The two-year intervention included weekly, mentor-led, girls group meetings on health, life skills and financial education. Additional intervention components included a health voucher redeemable for general wellness and reproductive health services and an adolescent-friendly savings account. Methods A cluster-randomized-controlled trial with longitudinal observations evaluated the impact of AGEP on key indicators immediately and two years after program end. Baseline data were collected from never-married adolescent girls in 120 intervention clusters (3515 girls) and 40 control clusters (1146 girls) and again two and four years later. An intent-to-treat analysis assessed the impact of AGEP on girls’ social, health and economic assets, sexual behaviors, education and fertility outcomes. A treatment-on-the-treated analysis using two-stage, instrumental variables regression was also conducted to assess program impact for those who participated. Results The intervention had modest, positive impacts on sexual and reproductive health knowledge after two and four years, financial literacy after two years, savings behavior after two and four years, self-efficacy after four years and transactional sex after two and four years. There was no effect of AGEP on the primary education or fertility outcomes, nor on norms regarding gender equity, acceptability of intimate partner violence and HIV knowledge. Conclusions Although the intervention led to sustained change in a small number of individual outcomes, overall, the intervention did not lead to girls acquiring a comprehensive set of social, health and economic assets, or change their educational and fertility outcomes. It is important to explore additional interventions that may be needed for the most vulnerable girls, particularly those that address household economic conditions. Additional attention should be given to the social and economic environment in which girls are living. Trial registration ISRCTN29322231. Trial Registration Date: March 04, 2016; retrospectively registered.

Minor mergers have been proposed as the driving mechanism for the size growth of quiescent galaxies with decreasing redshift. The process whereby large star-forming galaxies quench and join the quiescent population at the large size end has also been suggested as an explanation for this size growth. Given the clear association of quenching with clusters, we explore this mechanism by studying the structural properties of 23 spectroscopically identified recently quenched (or "poststarburst" (PSB)) cluster galaxies at $z\sim1$. Despite clear PSB spectral signatures implying rapid and violent quenching, 87\% of these galaxies have symmetric, undisturbed morphologies in the stellar continuum. Remarkably, they follow a mass-size relation lying midway between the star-forming and quiescent field relations, with sizes $0.1$ dex smaller than $z\sim1$ star-forming galaxies at log$(M_{*}/M_{\odot})=10.5$. This implies a rapid change in the light profile without directly effecting the stellar distribution, suggesting changes in the mass-to-light ratio gradients across the galaxy are responsible. We develop fading toy models to explore how star-forming galaxies move across the mass-size plane as their stellar populations fade to match those of the PSBs. "Outside-in" fading has the potential to reproduce the contraction in size and increase in bulge-dominance observed between star-forming and PSB cluster galaxies. Since cluster PSBs lie on the large size end of the quiescent mass-size relation, and our previous work shows cluster galaxies are smaller than field galaxies, the sizes of quiescent galaxies must grow both from the quenching of star-forming galaxies and dry minor mergers., Comment: 25 pages, 10 figures, accepted for publication in MNRAS

Minor mergers are thought to be responsible for the size growth of quiescent field galaxies with decreasing redshift. We test this hypothesis using the cluster environment as a laboratory. Satellite galaxies in clusters move at high velocities, making mergers between them rare. The stellar mass-size relation in ten clusters and in the field is measured and compared at $z~\mathtt{\sim}~1$. Our cluster sample contains 344 spectroscopically-confirmed cluster members with Gemini/GMOS and 182 confirmed with HST WFC3 G141 grism spectroscopy. On average, quiescent and star-forming cluster galaxies are smaller than their field counterparts by ($0.08\pm0.04$) dex and ($0.07\pm0.01$) dex respectively. These size offsets are consistent with the average sizes of quiescent and star-forming field galaxies between $1.2\leqslant z\leqslant1.5$, implying the cluster environment has inhibited size growth between this period and $z~\mathtt{\sim}~1$. The negligible differences measured between the $z~\mathtt{\sim}~0$ field and cluster quiescent mass-size relations in other works imply that the average size of quiescent cluster galaxies must rise with decreasing redshift. Using a toy model, we show that the disappearance of the compact cluster galaxies might be explained if, on average, $\mathtt{\sim}40\%$ of them merge with their brightest cluster galaxies (BCGs) and $\mathtt{\sim}60\%$ are tidally destroyed into the intra-cluster light (ICL) between $0\leqslant z\leqslant1$. This is in agreement with the observed stellar mass growth of BCGs between $0\leqslant z\leqslant1$ and the observed ICL stellar mass fraction at $z~\mathtt{\sim}~0$. Our results support minor mergers as the cause for the size growth in quiescent field galaxies, with cluster-specific processes responsible for the similarity between the field and cluster quiescent mass-size relations at low redshift., 25 pages, 13 figures, accepted for publication in MNRAS

We characterise ionised gas outflows using a large sample of ~330 high-luminosity (45.5 < log(L_bol/erg s^-1) < 49.0), high-redshift (1.5 < z < 4.0) quasars via their [OIII]4960,5008 emission. The median velocity width of the [OIII] emission line is 1540 kms^-1, increasing with increasing quasar luminosity. Broad, blue-shifted wings are seen in the [OIII] profiles of 42 per cent of the sample. Rest-frame ultraviolet spectra with well-characterised CIV 1550 emission line properties are available for more than 210 quasars, allowing an investigation of the relationship between the Broad Line Region (BLR) and Narrow Line Region (NLR) emission properties. The [OIII] blueshift is correlated with CIV blueshift, even when the dependence of both quantities on quasar luminosity has been taken into account. A strong anti-correlation between the [OIII] equivalent width (EW) and CIV blueshift also exists. Furthermore, [OIII] is very weak, with EW, MNRAS in press

We present the discovery of a new $z \sim 6.8$ quasar discovered with the near-IR VISTA Hemisphere Survey (VHS) which has been spectroscopically confirmed by the ESO New Technology Telescope (NTT) and the Magellan telescope. This quasar has been selected by spectral energy distribution (SED) classification using near infrared data from VISTA, optical data from Pan-STARRS, and mid-IR data from WISE. The SED classification algorithm is used to statistically rank two classes; foreground Galactic low-mass stars and high redshift quasars, prior to spectroscopic observation. Forced photometry on Pan-STARRS pixels for VHS J0411-0907 allows to improve the SED classification reduced-$��^2$ and photometric redshift. VHS J0411-0907 ($z=6.82$, $y_{AB} = 20.1$ mag, $J_{AB} = 20.0$ mag) has the brightest J-band continuum magnitude of the nine known quasars at $z > 6.7$ and is currently the highest redshift quasar detected in the Pan-STARRS survey. This quasar has one of the lowest black hole mass ($M_{\rm{BH}}= (6.13 \pm 0.51)\times 10^8\:\mathrm{M_{\odot}}$) and the highest Eddington ratio ($2.37\pm0.22$) of the known quasars at $z>6.5$. The high Eddington ratio indicates that some very high-$z$ quasars are undergoing super Eddington accretion. We also present coefficients of the best polynomials fits for colours vs spectral type on the Pan-STARRS, VISTA and WISE system for MLT dwarfs and present a forecast for the expected numbers of quasars at $z>6.5$., 14 pages, accepted for publication by MNRAS

Background Few studies have explored the association between depressive symptoms, HIV infection and stigma in vulnerable populations. The objective of this study is to examine factors associated with depressive symptoms among caregivers living in vulnerable households in Malawi and assess how reported depressive symptoms and other factors affect ART adherence among caregivers who report testing positive for HIV and currently on ART. Methods We interviewed 818 adult caregivers of children aged 0–17 years living in vulnerable households in 24 health facility catchment areas in five districts in rural southern Malawi in 2016–2017. Vulnerable households had either economic and food insecurity, or chronic illness. Questions on five depressive symptoms were used. ART adherence was self-report of not forgetting to take ART medication in the last week. Perceived and anticipated measures of stigma were used. Multivariable linear and logistic regressions documented relationships between depressive symptoms, self-reported HIV status, HIV-related stigma, and ART adherence. Results Most caregivers were women (86.2%); about one third had no spouse or live-in partner. Fifty-seven percent of caregivers reported having three or more depressive symptoms. Forty-one percent of caregivers reported testing positive for HIV. Self-reported HIV positive status was associated with depressive symptoms (adjusted coeff = 0.355, p-value Conclusions Addressing mental health among caregivers in vulnerable households may be an important step toward achieving viral suppression among vulnerable populations living with HIV in Malawi. Integrating depression screening into HIV care and treatment protocols could be a promising intervention to improve longer-term outcomes.

High ionization star forming (SF) galaxies are easily identified with strong emission line techniques such as the BPT diagram, and form an obvious ionization sequence on such diagrams. We use a locally optimally emitting cloud model to fit emission line ratios that constrain the excitation mechanism, spectral energy distribution, abundances and physical conditions along the star-formation ionization sequence. Our analysis takes advantage of the identification of a sample of pure star-forming galaxies, to define the ionization sequence, via mean field independent component analysis. Previous work has suggested that the major parameter controlling the ionization level in SF galaxies is the metallicity. Here we show that the observed SF- sequence could alternatively be interpreted primarily as a sequence in the distribution of the ionizing flux incident on gas spread throughout a galaxy. Metallicity variations remain necessary to model the SF-sequence, however, our best models indicate that galaxies with the highest and lowest observed ionization levels (outside the range -0.37 < log [O III]/H\b{eta} < -0.09) require the variation of an additional physical parameter other than metallicity, which we determine to be the distribution of ionizing flux in the galaxy., 41 pages, 17 figures, 9 tables, accepted to MNRAS

We study the interstellar medium (ISM) properties of three heavily reddened quasars at $z\sim2.5$ as well as three millimetre-bright companion galaxies near these quasars. New JVLA and ALMA observations constrain the CO(1-0), CO(7-6) and [CI]$^3$P$_2-^3$P$_1$ line emission as well as the far infrared to radio continuum. The gas excitation and physical properties of the ISM are constrained by comparing our observations to photo-dissociation region (PDR) models. The ISM in our high-redshift quasars is composed of very high-density, high-temperature gas which is already highly enriched in elements like carbon. One of our quasar hosts is shown to be a close-separation ($, Comment: Accepted for publication in MNRAS (18 pages, 10 figures and 5 tables)