Unmasking the Active Galactic Nucleus in PKS J2310-437

PKS J2310-437 is an AGN with bright X-ray emission relative to its weak radio emission and optical continuum. It is believed that its jet lies far enough from the line of sight that it is not highly relativistically beamed. It thus provides an extreme test of AGN models. We present new observations aimed at refining the measurement of the source's properties. In optical photometry with the NTT we measure a central excess with relatively steep spectrum lying above the bright elliptical galaxy emission, and we associate the excess wholly or in part with the AGN. A new full-track radio observation with the ATCA finds that the core 8.64GHz emission has varied by about 20 per cent over 38 months, and improves the mapping of the weak jet. With Chandra we measure a well-constrained power-law spectral index for the X-ray core, uncontaminated by extended emission from the cluster environment, with a negligible level of intrinsic absorption. Weak X-ray emission from the resolved radio jet is also measured. Our analysis suggests that the optical continuum in this radio galaxy has varied by at least a factor of four over a timescale of about two years, something that should be testable with further observations. We conclude that the most likely explanation for the bright central X-ray emission is synchrotron radiation from high-energy electrons.Comment: 7 pages, 12 figure

Reversible GANs for Memory-efficient Image-to-Image Translation

The Pix2pix and CycleGAN losses have vastly improved the qualitative and quantitative visual quality of results in image-to-image translation tasks. We extend this framework by exploring approximately invertible architectures which are well suited to these losses. These architectures are approximately invertible by design and thus partially satisfy cycle-consistency before training even begins. Furthermore, since invertible architectures have constant memory complexity in depth, these models can be built arbitrarily deep. We are able to demonstrate superior quantitative output on the Cityscapes and Maps datasets at near constant memory budget

A limit to the X-ray luminosity of nearby normal galaxies

Emission is studied at luminosities lower than those for which individual discrete sources can be studied. It is shown that normal galaxies do not appear to provide the numerous low luminosity X-ray sources which could make up the 2-60 keV diffuse background. Indeed, upper limits suggest luminosities comparable with, or a little less than, that of the galaxy. This is consistent with the fact that the average optical luminosity of the sample galaxies within approximately 20 Mpc is slightly lower than that of the galaxy. An upper limit of approximately 1% of the diffuse background from such sources is derived

Galaxy gas ejection in radio galaxies: the case of 3C 35

We report results from XMM-Newton and Chandra observations of the nearby (z = 0.067) giant radio galaxy 3C 35. We find evidence for an X-ray emitting gas belt, orthogonal to and lying between the lobes of 3C 35, which we interpret as fossil-group gas driven outwards by the expanding radio lobes. We also detect weak emission from a second, more extended group-type environment, as well as inverse-Compton X-ray emission from the radio lobes. The morphological structure of the radio lobes and gas belt point to co-evolution. Furthermore, the radio source is powerful enough to eject galaxy-scale gas out to distances of 100kpc, and the ages of the two features are comparable (tsynch~140Myr, tbelt~80 Myr). The destruction of 3C 35's atmosphere may offer clues as to how fossil systems are regulated: radio galaxies need to be of power comparable to 3C 35 to displace and regulate fossil-group gas. We discuss the implications of the gas belt in 3C 35 in terms of AGN fuelling and feedback.Comment: 18 pages, accepted to MNRA

Barriers to women in the UK construction industry

Purpose – This paper aims to identify the main barriers that lead to the under-representation of women in the UK construction industry. The study, funded by ConstructionSkills, seeks to explore the issues that women face and investigate the potential positive impact that continuous professional development (CPD) may have upon improving the retention and career progression of women. Design/methodology/approach – The study uses an open-ended grounded theory (GT) approach, including 231 semi-structured questionnaires and nine focus groups with women from a range of professional occupations. All the findings were analysed using keyword analysis to identify the top two barriers that women face, alongside a series of cross-cutting key themes and issues. Findings – The findings reveal that male-dominated organisational cultures and inflexible working practices are the main barriers to women in the UK construction industry, irrespective of job role or profession. This paper concludes by arguing for a sea-change in the expansion of CPD opportunities for women in managerial, confidence and communication based skills, with accompanying networking and support systems to facilitate the retention and advancement of women in the industry sector. Research limitations/implications – Due to the research approach, the data are not generalisable. Therefore, researchers are advised to research and test the findings with a larger group. Researchers are also recommended to investigate the impact of expanded CPD opportunities for both men and women. Originality/value – The paper puts forward a business case for the advancement of specific CPD training for women, to facilitate the expansion of equality and diversity in the workforce in the UK construction industry

Examining eShift through the Caregiver Policy Lens: A Content Analysis

Purpose: This research study intended to understand how a new model of palliative home care in Ontario, Canada called eShift aligned with the needs of caregivers who cared for a family member at the end-of-life. Methods: A qualitative secondary analysis using a deductive content analysis of 14 caregiver interviews, three decision-maker interviews, and six home care agency documents collected in a three-year study and were analyzed using The Caregiver Policy Lens framework. Findings: The eShift model of care met caregivers’ needs through timely access to respite, education, collaborating with the health care team, and physical and psychological support. Caregivers were supported in their caregiving role, however, they felt continuity of care could be improved. Conclusion: This study suggests that the eShift model of palliative home care provides many of the supports needed by caregivers while they care for family members in the home at the end-of-life

Multiple description video coding for stereoscopic 3D

In this paper, we propose an MDC schemes for stereoscopic 3D video. In the literature, MDC has previously been applied in 2D video but not so much in 3D video. The proposed algorithm enhances the error resilience of the 3D video using the combination of even and odd frame based MDC while retaining good temporal prediction efficiency for video over error-prone networks. Improvements are made to the original even and odd frame MDC scheme by adding a controllable amount of side information to improve frame interpolation at the decoder. The side information is also sent according to the video sequence motion for further improvement. The performance of the proposed algorithms is evaluated in error free and error prone environments especially for wireless channels. Simulation results show improved performance using the proposed MDC at high error rates compared to the single description coding (SDC) and the original even and odd frame MDC

The magnetic field and geometry of the oblique shock in the jet of 3C 346

We investigate the brightest regions of the kpc-scale jet in the powerful radio galaxy 3C 346, using new optical HST ACS/F606W polarimetry together with Chandra X-ray data and 14.9 GHz and 22.5 GHz VLA radio polarimetry. The jet shows a close correspondence in optical and radio morphology, while the X-ray emission shows an 0.80 +/- 0.17 kpc offset from the optical and radio peak positions. Optical and radio polarimetry show the same apparent magnetic field position angle and fractional polarization at the brightest knot, where the jet undergoes a large kink of almost 70 degrees in the optical and radio images. The apparent field direction here is well-aligned with the new jet direction, as predicted by earlier work that suggested the kink was the result of an oblique shock. We have explored models of the polarization from oblique shocks to understand the geometry of the 3C 346 jet, and find that the upstream flow is likely to be highly relativistic (0.91 +0.05 / -0.07 c), where the plane of the shock front is inclined at an angle of 51 (+/- 11) degrees to the upstream flow which is at an angle 14 (+8 / -7) degrees to our line of sight. The actual deflection angle of the jet in this case is only 22 degrees.Comment: 11 pages, 5 figures. Accepted by MNRA

The jet and counterjet of 3C 270 (NGC 4261) viewed in the X-ray with Chandra

The radio source 3C 270, hosted by NGC 4261, is the brightest known example of counterjet X-ray emission from a low-power radio galaxy. We report on the X-ray emission of the jet and counterjet from 130 ks of Chandra data. We argue that the X-ray emission is synchrotron radiation and that the internal properties of the jet and counterjet are remarkably similar. We find a smooth connection in X-ray hardness and X-ray to radio ratio between the jet and one of the X-ray components within the core spectrum. We observe wedge-like depressions in diffuse X-ray surface brightness surrounding the jets, and interpret them as regions where an aged population of electrons provides pressure to balance the interstellar medium of NGC 4261. About 20% of the mass of the interstellar medium has been displaced by the radio source. Treating 3C 270 as a twin-jet system, we find an interesting agreement between the ratio of jet-to-counterjet length in X-rays and that expected if X-rays are observed over the distance that an outflow from the core would have traveled in ~6x10^4 yr. X-ray synchrotron loss times are shorter than this, and we suggest that most particle acceleration arises as a result of turbulence and dissipation in a stratified flow. We speculate that an episode of activity in the central engine beginning ~6x10^4 yr ago has led to an increased velocity shear. This has enhanced the ability of the jet plasma to accelerate electrons to X-ray-synchrotron-emitting energies, forming the X-ray jet and counterjet that we see today.Comment: Accepted for publication in the MNRAS. 12 pages, 10 figs (some in color).Some figures reduced in qualit