The Milky Way bar/bulge in proper motions: a 3D view from VIRAC & Gaia

© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We have derived absolute proper motions of the entire Galactic bulge region from VIRAC and Gaia. We present these as both integrated on-sky maps and, after isolating standard candle red clump (RC) stars, as a function of distance using RC magnitude as a proxy. These data provide a new global, 3-dimensional view of the Milky Way barred bulge kinematics. We find a gradient in the mean longitudinal proper motion, $\mu_l$, between the different sides of the bar, which is sensitive to the bar pattern speed. The split RC has distinct proper motions and is colder than other stars at similar distance. The proper motion correlation map has a quadrupole pattern in all magnitude slices showing no evidence for a separate, more axisymmetric inner bulge component. The line-of-sight integrated kinematic maps show a high central velocity dispersion surrounded by a more asymmetric dispersion profile. $\sigma_{\mu_l} / \sigma_{\mu_b}$ is smallest, $\sim1.1$, near the minor axis and reaches $\sim1.4$ near the disc plane. The integrated $$ pattern signals a superposition of bar rotation and internal streaming motion, with the near part shrinking in latitude and the far part expanding. To understand and interpret these remarkable data, we compare to a made-to-measure barred dynamical model, folding in the VIRAC selection function to construct mock maps. We find that our model of the barred bulge, with a pattern speed of 37.5 $\mathrm{km \, s^{-1} \, kpc^{-1}}$, is able to reproduce all observed features impressively well. Dynamical models like this will be key to unlocking the full potential of these data.Peer reviewe

Heart and Soul: A Phenomenology of Dementia Spouse Caregivers’ Relationship Closeness

All persons with dementia exhibit combinations of cognitive impairment (memory loss and aphasia), functional losses (changes in activities of daily living), and neuropsychiatric disease manifestations (fluctuating moods, behaviors and psychoses). The spouse caregiver role and life are affected by these symptoms which can cause intimacy, reciprocity, and communication issues, and frequently result in the caregiver’s feelings of inadequacy, hopelessness, and embarrassment. Yet caregivers somehow manage to reconstruct and maintain a closeness as a couple. Relationship closeness (RC) found in all marriages is simply depicted as the quality of the communal and emotional bond between husband and wife. Limited research demonstrates some elements of RC are altered by the progression of dementia disease and links RC with the couple’s morbidity (ill health and depression) and caregiving outcomes (burden, coping, transcendence and efficacy). But RC is poorly defined in published studies, and not adequately or critically examined in context with dementia’s cognitive impairment and neuropsychiatric symptoms, whose very characteristics disrupt critical elements of interpersonal relationships. The purpose of this descriptive phenomenological study was to investigate the phenomenon of spouse caregiver RC; it focused on dementia and the sequelae of dementia symptoms and behaviors. The research questions were: 1) what is the fundamental structure of this phenomenon, and2) what is the meaning of the experience of this phenomenon. This inquiry uncovered a rich description of marital RC in couples, by focusing on their memories and lived-world experiences as caring partners, and as their spouse expressed dementia symptoms daily. Both theoretical underpinnings and qualitative research design used Colaizzi’s existential philosophy and Phenomenological Reflection method of data analysis. Data emerged from the author’s Individual Phenomenological Reflection and sixteen dialogal interviews. Findings revealed the meaning of the fundamental structure of RC in the face of dementia as a journey. Five essential constituents emerged: A past together, the present in which spouses see, feel and respond to the dementia, and lastly, a future together. The meaning expressed by spouses was woven in a tapestry of dementia symptomatology, and dyadic internal and external changes in RC described with important sub-themes such as loss and hurt, imperfect caregiving and compassionate love

On the distribution of an effective channel estimator for multi-cell massive MIMO

Accurate channel estimation is of utmost importance for massive MIMO systems to provide significant improvements in spectral and energy efficiency. In this work, we present a study on the distribution of a simple but yet effective and practical channel estimator for multi-cell massive MIMO systems suffering from pilot-contamination. The proposed channel estimator performs well under moderate to aggressive pilot contamination scenarios without previous knowledge of the inter-cell large-scale channel coefficients and noise power, asymptotically approximating the performance of the linear MMSE estimator as the number of antennas increases. We prove that the distribution of the proposed channel estimator can be accurately approximated by the circularly-symmetric complex normal distribution, when the number of antennas, M, deployed at the base station is greater than 10

ROSAT PSPC observations of the outer regions of the Perseus cluster of galaxies

We present an analysis of four off-axis ROSAT PSPC observations of the Perseus cluster of galaxies (Abell~426). We detect the surface brightness profile to a radius of 80 arcmin ($\sim 2.4 h_{50}^{-1}$ Mpc) from the X-ray peak. The profile is measured in various sectors and in three different energy bands. Firstly, a colour analysis highlights a slight variation of $N_{H}$ over the region, and cool components in the core and in the eastern sector. We apply the $\beta$-model to the profiles from different sectors and present a solution to the, so-called, $\beta$-problem. The residuals from an azimuthally-averaged profile highlight extended emission both in the East and in the West, with estimated luminosities of about 8 and 1 $\times 10^{43} erg/s$, respectively. We fit several models to the surface brightness profile, including the one obtained from the Navarro, Frenk and White (1995) potential. We obtain the best fit with the gas distribution described by a power law in the inner, cooling region and a $\beta$-model for the extended emission. Through the best-fit results and the constraints from the deprojection of the surface brightness profiles, we define the radius where the overdensity inside the cluster is 200 times the critical value, $r_{200}$, at $2.7 h_{50}^{-1}$ Mpc. Within $2.3 h_{50}^{-1}$ Mpc ($0.85 r_{200}$), the total mass in the Perseus cluster is $1.2 \times 10^{15} M_{\odot}$ and its gas fraction is about 30 per cent.Comment: 21 pages, 23 figures; accepted for publication in MNRAS; also available at http://www-xray.ast.cam.ac.uk/~settori/paper.htm

Production of Enhanced Beam Halos via Collective Modes and Colored Noise

We investigate how collective modes and colored noise conspire to produce a beam halo with much larger amplitude than could be generated by either phenomenon separately. The collective modes are lowest-order radial eigenmodes calculated self-consistently for a configuration corresponding to a direct-current, cylindrically symmetric, warm-fluid Kapchinskij-Vladimirskij equilibrium. The colored noise arises from unavoidable machine errors and influences the internal space-charge force. Its presence quickly launches statistically rare particles to ever-growing amplitudes by continually kicking them back into phase with the collective-mode oscillations. The halo amplitude is essentially the same for purely radial orbits as for orbits that are initially purely azimuthal; orbital angular momentum has no statistically significant impact. Factors that do have an impact include the amplitudes of the collective modes and the strength and autocorrelation time of the colored noise. The underlying dynamics ensues because the noise breaks the Kolmogorov-Arnol'd-Moser tori that otherwise would confine the beam. These tori are fragile; even very weak noise will eventually break them, though the time scale for their disintegration depends on the noise strength. Both collective modes and noise are therefore centrally important to the dynamics of halo formation in real beams.Comment: For full resolution pictures please go to http://www.nicadd.niu.edu/research/beams