Deep spectroscopy of z~1 6C radio galaxies - II. Breaking the redshift-radio power degeneracy

The results of a spectroscopic analysis of 3CR and 6C radio galaxies at redshift z~1 are contrasted with the properties of lower redshift radio galaxies, chosen to be matched in radio luminosity to the 6C sources studied at z~1, thus enabling the P-z degeneracy to be broken. Partial rank correlations and principal component analysis have been used to determine which of z and P are the critical parameters underlying the observed variation of the ionization state andd kinematics of the emission line gas. [OII]/H-beta is shown to be a useful ionization mechanism diagnostic. Statistical analysis of the data shows that the ionization state of the emission line gas is strongly correlated with radio power, once the effects of other parameters are removed. No dependence of ionization state on z is observed, implying that the ionization state of the emission line gas is solely a function of the AGN properties rather than the hostt galaxy and/or environment. Statistical analysis of the kinematic properties of the emission line gas shows that these are strongly correlated independently withh both P and z. The correlation with redshift is the stronger of the two, suggesting that host galaxy composition or environment may play a role in producing the less extreme gas kinematics observed in the emission line regions of low redshift galaxies. For both the ionization and kinematic properties of thee galaxies, the independent correlations observed with radio size are strongest. Radio source age is a determining factor for the extended emission line regions.Comment: 10 pages, 5 figures, accepted for publication in MNRA

HST and UKIRT imaging observations of z ~ 1 6C radio galaxies - I. The data

The results of Hubble Space Telescope and UKIRT imaging observations are presented for a sample of 11 6C radio galaxies with redshifts 0.85 < z < 1.5. The observations of the 6C sources reveal a variety of different features, similar to those observed around the higher luminosity of the aligned emission appears less extreme in the case of the 6C radio galaxies. For both samples, the aligned emission clearly cannot be explained by a single emission mechanism; line emission and related nebular continuum emission, however, often provide a significant contribution to the aligned emission.Comment: 17 pages, 11 figures (figs 3,6,11 low resolution - full resolution images can be obtained from http://www.mrao.cam.ac.uk/~kji/ImagingFigs/). Accepted for publication in MNRA

HST and UKIRT imaging observations of z~1 6C radio galaxies - II. Galaxy morphologies and the alignment effect

(abridged) Powerful radio galaxies often display enhanced optical/UV emission regions, elongated and aligned with the radio jet axis. The aim of this series of papers is to separately investigate the effects of radio power and redshift on the alignment effect, together with other radio galaxy properties. In this second paper, we present a deeper analysis of the morphological properties of these systems, including both the host galaxies and their surrounding aligned emission. The host galaxies of our 6C subsample are well described as de Vaucouleurs ellipticals, with typical scale sizes of ~10kpc. This is comparable to the host galaxies of low-z radio sources of similar powers, and also the more powerful 3CR sources at the same redshift. The contribution of nuclear point source emission is also comparable, regardless of radio power. The 6C alignment effect is remarkably similar to that seen around more powerful 3CR sources at the same redshift in terms of extent and degree of alignment with the radio source axis, although it is generally less luminous. The bright, knotty features observed in the case of the z~1 3CR sources are far less frequent in our 6C subsample; neither do we observe such strong evidence for evolution in the strength of the alignment effect with radio source size/age. However, we do find a very strong link between the most extreme alignment effects and emission line region properties indicative of shocks, regardless of source size/age or power. In general, the 6C alignment effect is still considerably stronger than that seen around lower redshift galaxies of similar radio powers. (abridged)Comment: 23 pages, 15 figures, accepted for publication in MNRAS. See http://www.mrao.cam.ac.uk/~kji/MorphPaper/ for version of paper with full resolution images of Figs 1-1

Beyond Birthweight: The Origins of Human Capital

Birth weight is the most widely used indicator of neonatal health, mainly because it is routinely recorded in birth registries. But are better measures available? We use unique data including fetal ultrasounds to show that more specific measures of the fetus and of the newborn are more informative about the prenatal environment and more predictive of child health and development, beyond birth weight. Our results are robust to correcting for measurement error and accounting for child- and mother-specific unobserved heterogeneity. Our analysis rationalises a common finding in the early origins literature, that prenatal events can influence postnatal development without affecting birth outcomes

Engaging teenagers in improving their health behaviours and increasing their interest in science (Evaluation of LifeLab Southampton): study protocol for a cluster randomized controlled trial

BackgroundLifestyle and health behaviours are strongly linked to non-communicable disease risk, but modifying them is challenging. There is an increasing recognition that adolescence is an important time when lifestyle and health behaviours become embedded. Improving these in adolescents is important not only for their own health but also for that of their future children. LifeLab Southampton has been developed as a purpose-built classroom and laboratory in University Hospital Southampton. Secondary school students visit LifeLab to learn how childhood, adolescent and parental nutrition influences health, understand the impact of their lifestyle on their cardiovascular and metabolic health, and to inspire them with the excitement of research and future career possibilities in science. The LifeLab visit is part of a programme of work linked to the English National Curriculum. Pilot work has indicated that attitudes towards health can be changed by such LifeLab sessions. MethodsA cluster randomised controlled trial is being conducted to evaluate the effectiveness of the LifeLab intervention, the primary outcome being a measurement of the change in nutrition, health and lifestyle literacy from before to after the LifeLab intervention. The LifeLab intervention comprises: professional development for the teachers involved, preparatory-lessons for the school students, delivered in school, a hands-on practical day at LifeLab including a ‘Meet the Scientist’ session, post-visit lessons delivered in school and the opportunity to participate in the annual LifeLab Schools’ Conference. This study aims to recruit approximately 2,500 secondary school students aged 13-14 years from 32 schools (the clusters) from Southampton and neighbouring areas. Participating schools will be randomised to control or intervention groups. The intervention will be run over two academic school years, with baseline questionnaire data collected from students at participating schools at the start of the academic year and follow- up questionnaire data collected approximately 12 months later.Evaluation of LifeLab is a cluster randomised controlled trial (ISRCTN71951436, registered 25th March 2015), funded by the British Heart Foundation (PG/14/33/30827)

Childhood vascular phenotypes have differing associations with pre- and postnatal growth

Objective: In children aged 8--9 years, we examined the associations of linear and abdominal circumference growth during critical stages of prenatal and postnatal development with six vascular measurements commonly used as early markers of atherosclerosis and later cardiovascular disease (CVD) risk. Methods: In 724 children from the UK Southampton Women's Survey mother--offspring cohort, offspring length/height and abdominal circumference measurements were collected at 10 ages between 11 weeks’ gestation and age 8--9 years. Using residual growth modelling and linear regression, we examined the independent associations between growth and detailed vascular measures made at 8--9 years. Results: Postnatal linear and abdominal circumference growth were associated with higher childhood SBP and carotid--femoral pulse wave velocity, whereas prenatal growth was not. For example, 1SD faster abdominal circumference gain between ages 3 and 6 years was associated with 2.27 [95% confidence interval (CI): 1.56--2.98] mmHg higher SBP. In contrast, faster abdominal circumference gain before 19 weeks’ gestation was associated with greater carotid intima--media thickness [0.009 mm (0.004--0.015) per 1SD larger 19-week abdominal circumference), whereas later growth was not. We found no strong associations between prenatal or postnatal growth and DBP or measures of endothelial function. Conclusion: Higher postnatal linear growth and adiposity gain are related to higher SBP and carotid--femoral pulse wave velocity in childhood. In contrast, faster growth in early gestation is associated with greater childhood carotid intima--media thickness, perhaps resulting from subtle changes in vascular structure that reflect physiological adaptations rather than subclinical atherosclerosis

Compact radio sources and jet-driven AGN feedback in the early Universe: Constraints from integral-field spectroscopy

To investigate the impact of radio jets during the formation epoch of their massive host galaxies, we present an analysis of two massive, log(M_stel/ M_sun)~10.6 and 11.3, compact radio galaxies at z=3.5, TNJ0205+2242 and TNJ0121+1320. Their small radio sizes (R<= 10 kpc) are most likely a sign of youth. We compare their radio properties and gas dynamics with those in well extended radio galaxies at high redshift, which show strong evidence for powerful, jet-driven outflows of significant gas masses (M 10^9-10 M_sun). Our analysis combines rest-frame optical integral-field spectroscopy with existing radio imaging, CO emission line spectra, and rest-frame UV spectroscopy. [OIII]5007 line emission is compact in both galaxies and lies within the region defined by the radio lobes. For TNJ0205+2242, the Ly-alpha profile narrows significantly outside the jet radius, indicating the presence of a quiescent halo. TNJ0121+1320 has two components separated by ~10 kpc and a velocity offset of ~300 km s^-1. If motions are gravitational, this implies a dynamical mass of 2x10^11 M_sun for the more massive, radio-loud component. The dynamical mass, molecular gas mass measured from the CO line emission, and radio luminosity of these two compact radio galaxies imply that compact radio sources may well develop large-scale, energetic outflows as observed in extended radio galaxies, with the potential of removing significant fractions of the ISM from the host galaxy. The absence of luminous emission line gas extending beyond the radio emission in these sources agrees with the observed timescales and outflow rates in extended radio galaxies, and adds further evidence that the energetic, large-scale outflows observed in extended radio sources (Nesvadba et al. 2006) are indeed the result of influence of the radio jet.Comment: A&A accepte

Deep spectroscopy of z~1 6C radio galaxies - I. The effects of radio power and size on the properties of the emission line gas

(abridged) The results of deep long-slit optical spectroscopy for a sample of 8 6C radio galaxies at z~1 are presented. Emission line ratios are derived for emission lines with rest-frame wavelengths of 1500 - 4500Ang, and the kinematic propertiess of the emission line gas are derived from an analysis of the 2-d structure of thee [OII]3727 Ang emission line at ~5Ang spectral resolution. In general, the 6C spectra display many characteristics similar to those of more powerful 3CR sources at the same redshifts. The emission line region gas kinematics are more extreme for the smaller radio sources in the sample, which often display distorted velocity profiles. The ionization state of the emission line region also varies with radio size: the spectra of large radio sources (>120kpc) are consistent with photoionization by an obscured AGN, whilst smaller (<120kpc) sources typically exist in a lower ionization state and have spectra which are better explained by additional ionization due to shocks associated with the expanding radio source. The kinematic and ionization properties of the 6C radio galaxies are clearly linked. As for the 3CR sources, smaller radio sources also typically possess more extensive emission line regions, with enhanced emission line luminosities. It is clear that the best interpretation of the spectra of radio sources requires a combination of ionization mechanisms.Comment: 29 pages, 22 figures, accepted for publication in MNRA