Teacher perspectives of cultivating learning through practitioner enquiry to transform practice

This paper reports on the first year of an innovative Postgraduate Certificate (PGCert) in Advanced Education Practice, designed to meet the specific staff and development needs of one school in the North West of England. The programme is underpinned by three strands of practice based learning: learning about practice (theory), learning in practice (application) and learning through practice (reflection) through critical reflection. This paper considers professional development situated around teaching and learning and outlines a new approach to cultivating learning, both for teachers and educational practitioners through a collaborative learning model with a Higher Education Institute (HEI). A further strand to the research considers transformative impact on practice including references to personal experience and reflections by the participants. Throughout the report it is evident that school leaders were keen to enhance the performance of staff by supporting them in Masters level study to enhance professional practice and impact on learning. Through questionnaires and interviews, an insight into personal and professional impact, challenges, evaluation, details of the progression, next steps in the small scale research study were considered

Teacher perspectives of cultivating learning through practitioner enquiry to transform practice

This paper reports on the first year of an innovative Postgraduate Certificate (PGCert) in Advanced Education Practice, designed to meet the specific staff and development needs of one school in the North West of England. The programme is underpinned by three strands of practice based learning: learning about practice (theory), learning in practice (application) and learning through practice (reflection) through critical reflection. This paper considers professional development situated around teaching and learning and outlines a new approach to cultivating learning, both for teachers and educational practitioners through a collaborative learning model with a Higher Education Institute (HEI). A further strand to the research considers transformative impact on practice including references to personal experience and reflections by the participants. Throughout the report it is evident that school leaders were keen to enhance the performance of staff by supporting them in Masters level study to enhance professional practice and impact on learning. Through questionnaires and interviews, an insight into personal and professional impact, challenges, evaluation, details of the progression, next steps in the small scale research study were considered

Further evidence for a merger in Abell 2218 from an XMM-Newton observation

(Abridged) The galaxy cluster Abell 2218, at z=0.171, is well-known for the discrepancy between mass estimates derived from X-ray and strong lensing analyses. With the present XMM observation, we trace the gas density and temperature profiles out to a radius of ~ 1400 h_70^-1 kpc (approximately the virial radius of the cluster). The surface brightness profile is well fitted over three orders of magnitude with a beta model, with a core radius of 0.'95 and \beta=0.63. The projected temperature profile declines steeply with radius (by ~50%), and is well described by a polytrope with parameters t_0=8.09 keV and \gamma=1.15. The temperature map shows a pronounced peak in the central arcminute, with an increase of a factor of two (from ~5 to ~10 keV). The mass profile, calculated assuming hydrostatic equilibrium and spherical symmetry, is best fitted with a King approximation to an isothermal sphere, implying a dark matter distribution with a central core, in contrast with the cusped cores found in more obviously relaxed clusters. The X-ray mass is two times less than the strong lensing mass at r ~ 80 h_50^-1 kpc, although the agreement between X-ray and weak lensing mass measurements at larger radius (r ~ 400 h_50^-1 kpc) is slightly better. While the X-ray total mass estimates can vary by 30% depending on the mass model, all measurements are lower than the corresponding total mass from optical measurements. Given the X-ray results indicating disturbance of the intracluster gas, leading to a likely violation of the assumption of hydrostatic equilibrium, and the observed substructure in the optical, suggesting a line-of-sight merger, it is unlikely that the different mass estimates of this cluster can be reconciled, at least with standard modelling assumptions.Comment: 9 pages, 7 figures; to appear in A&

Entropy profiles in X-ray luminous galaxy clusters at z>0.1

[Abridged] The entropy distribution of the intracluster gas reflects both accretion history of the gas and processes of feedback which provide a further non-gravitational energy besides the potential one. In this work, we study the profiles and the scaling properties of the gas entropy in 24 hot (kT_{gas} > 6 keV) galaxy clusters observed with Chandra in the redshift range 0.14-0.82 and showing different states of relaxation. We recover the gas density, temperature and entropy profiles in a non-parametric way. Adding the hydrostatic equilibrium hypothesis, radial profiles are also obtained from the deprojection of the surface brightness, allowing to verify whether the hydrostatic equilibrium is a tenable hypothesis by comparison with the spectral measurements. We confirm that this is the case on scales larger than 100 kpc and discuss the deviations observed in few non-cooling core clusters in the inner regions. We show that the entropy profiles are remarkably similar outside the core and can be described by simple power-laws with slope of 1.0-1.2. We measure an entropy level at 0.1 R_{200} of 100-500 keV cm^2 and a central plateau which spans a wide range of value (~ a few-200 keV cm^2) depending on the state of relaxation of the source. To characterize the energetic of the central regions, we compare the radial behaviour of the temperature of the gas with the temperature of the dark matter T_{DM} by estimating the excess of energy Delta E = 3/2 k(T_{gas}- T_{DM}). We point out that Delta E ranges from ~ 0 in typical cooling-core clusters to few keV within 100 kpc in non-cooling core systems. We also measure a significant correlation between the total iron mass and the entropy outside the cooling region,whereas in the inner regions they anti-correlate strongly.Comment: MNRAS in press - Minor revision to match the accepted versio

The cultural contradictions of the creative city

This paper is concerned with both what creative cities are imagined to be, as well as what they actually are. This is a challenge for policy makers. Overall, the paper seeks to create a platform for a more nuanced and subtle approach to creativity, culture and cities: one that is situated and not universal. It seeks to map out an approach that is concerned not simply with the growth possibilities, but also redistributive strategies. In so doing it questions whether can we conceive of creative cities as a truly progressive field of policy and practice, in direct contrast to what we judge to be the socially regressive form they take at present. The paper is divided into three main parts. The first locates the creative city within the discourse of place marketing, but flags up the tensions between the universalism of place marketing, and the particularities of culture and creativity. The second critically examines notions of liberalism and creativity as they underpin the creative city. The final part takes the actually existing creative city and highlights many of the negative and regressive elements of policies that promote them. The paper argues for the need for more nuanced approaches, and for more attention to the (lack of) redistributive outcomes in existing creative city debates

Structure and scaling of the entropy in nearby galaxy clusters

Using XMM-Newton observations, we investigate the scaling and structural properties of the ICM entropy in a sample of 10 nearby (z < 0.2) relaxed galaxy clusters in the temperature range 2-9 keV. We derive the local entropy-temperature (S-T) relation at R = 0.1, 0.2, 0.3 and 0.5 R_200. The logarithmic slope of the relation is the same within the 1\sigma error at all scaled radii. However, the intrinsic dispersion about the best fitting relation is significantly higher at 0.1 R_200. The slope is 0.64\pm0.11 at 0.3 R_200, in excellent agreement with previous work. We also investigate the entropy-mass relation at density contrasts \delta=5000, 2500 and 1000. We find a shallower slope than that expected in simple self-similar models, which is in agreement with the observed empirically-determined entropy-temperature and mass-temperature scaling. The dispersion is smaller than for the S-T relation. Once scaled appropriately, the entropy profiles appear similar beyond ~0.1 R_200, with an intrinsic dispersion of ~15 per cent and a shape consistent with gravitational heating (S(r) \propsim r^{1.1}). However, the scatter in scaled entropy profiles increases with smaller scaled radius, to more than 60 per cent at R \lesssim 0.05 R_200. Our results are in qualitative agreement with models which boost entropy production at the accretion shock. However, localised entropy modification may be needed to explain the dispersion in the inner regions.Comment: 9 pages, 8 colour figures, to appear in A&A. Title changed, minor text clarification

Bayesian modelling of the cool core galaxy group NGC 4325

We present an X-ray analysis of the radio-quiet cool-core galaxy group NGC 4325 (z=0.026) based on Chandra and ROSAT observations. The Chandra data were analysed using XSPEC deprojection, 2D spectral mapping and forward-fitting with parametric models. Additionally, a Markov chain Monte Carlo method was used to perform a joint Bayesian analysis of the Chandra and ROSAT data. The results of the various analysis methods are compared, particularly those obtained by forward-fitting and deprojection. The spectral mapping reveals the presence of cool gas displaced up to 10 kpc from the group centre. The Chandra X-ray surface brightness shows the group core to be highly disturbed, and indicates the presence of two small X-ray cavities within 15 kpc of the group core. The XSPEC deprojection analysis shows that the group has a particularly steep entropy profile, suggesting that an AGN outburst may be about to occur. With the evidence of prior AGN activity, but with no radio emission currently observed, we suggest that the group in in a pre-outburst state, with the cavities and displaced gas providing evidence of a previous, weak AGN outburst.Comment: 12 pages, 10 figures; accepted for publication in MNRA

A parametric physical model for the intracluster medium and its use in joint SZ/X-ray analyses of galaxy clusters

We present a parameterized model of the intra-cluster medium that is suitable for jointly analysing pointed observations of the Sunyaev-Zel'dovich (SZ) effect and X-ray emission in galaxy clusters. The model is based on assumptions of hydrostatic equilibrium, the Navarro, Frenk and White (NFW) model for the dark matter, and a softened power law profile for the gas entropy. We test this entropy-based model against high and low signal-to-noise mock observations of a relaxed and recently-merged cluster from N-body/hydrodynamic simulations, using Bayesian hyper-parameters to optimise the relative statistical weighting of the mock SZ and X-ray data. We find that it accurately reproduces both the global values of the cluster temperature, total mass and gas mass fraction (fgas), as well as the radial dependencies of these quantities outside of the core (r > kpc). For reference we also provide a comparison with results from the single isothermal beta model. We confirm previous results that the single isothermal beta model can result in significant biases in derived cluster properties.Comment: Published in MNRAS. 20 pages. 9 figure

A statistically-selected Chandra sample of 20 galaxy clusters -- II. Gas properties and cool-core/non-cool core bimodality

We investigate the thermodynamic and chemical structure of the intracluster medium (ICM) across a statistical sample of 20 galaxy clusters analysed with the Chandra X-ray satellite. In particular, we focus on the scaling properties of the gas density, metallicity and entropy and the comparison between clusters with and without cool cores (CCs). We find marked differences between the two categories except for the gas metallicity, which declines strongly with radius for all clusters (Z ~ r^{-0.31}), outside ~0.02 r500. The scaling of gas entropy is non-self-similar and we find clear evidence of bimodality in the distribution of logarithmic slopes of the entropy profiles. With only one exception, the steeper sloped entropy profiles are found in CC clusters whereas the flatter slope population are all non-CC clusters. We explore the role of thermal conduction in stabilizing the ICM and conclude that this mechanism alone is sufficient to balance cooling in non-CC clusters. However, CC clusters appear to form a distinct population in which heating from feedback is required in addition to conduction. Under the assumption that non-CC clusters are thermally stabilized by conduction alone, we find the distribution of Spitzer conduction suppression factors, f_c, to be log-normal, with a log (base 10) mean of -1.50+/-0.03 (i.e. f_c=0.032) and log standard deviation 0.39+/-0.02.Comment: 13 pages, 13 figures; accepted for publication in MNRA

How AGN feedback and metal cooling shape cluster entropy profiles

Observed clusters of galaxies essentially come in two flavors: non cool core clusters characterized by an isothermal temperature profile and a central entropy floor, and cool-core clusters where temperature and entropy in the central region are increasing with radius. Using cosmological resimulations of a galaxy cluster, we study the evolution of its intracluster medium (ICM) gas properties, and through them we assess the effect of different (sub-grid) modelling of the physical processes at play, namely gas cooling, star formation, feedback from supernovae and active galactic nuclei (AGN). More specifically we show that AGN feedback plays a major role in the pre-heating of the proto-cluster as it prevents a high concentration of mass from collecting in the center of the future galaxy cluster at early times. However, AGN activity during the cluster's later evolution is also required to regulate the mass flow into its core and prevent runaway star formation in the central galaxy. Whereas the energy deposited by supernovae alone is insufficient to prevent an overcooling catastrophe, supernovae are responsible for spreading a large amount of metals at high redshift, enhancing the cooling efficiency of the ICM gas. As the AGN energy release depends on the accretion rate of gas onto its central black hole engine, the AGN responds to this supernova enhanced gas accretion by injecting more energy into the surrounding gas, and as a result increases the amount of early pre-heating. We demonstrate that the interaction between an AGN jet and the ICM gas that regulates the growth of the AGN's BH, can naturally produce cool core clusters if we neglect metals. However, as soon as metals are allowed to contribute to the radiative cooling, only the non cool core solution is produced.Comment: 19 pages, 13 figures, accepted for publication in MNRA