266 research outputs found
Using Virtual Observatory techniques to search for Adaptive Optics suitable AGN
Until recently, it has been possible only for nearby galaxies to study the
scaling relations between central black hole and host galaxy in detail. Because
of the small number densities at low redshift, (luminous) AGN are
underrepresented in such detailed studies. The advent of adaptive optics (AO)
at large telescopes helps overcoming this hurdle, allowing to reach small
linear scales over a wide range in redshift. Finding AO-suitable targets, i.e.,
AGN having a nearby reference star, and carrying out an initial multiwavelength
classification is an excellent use case for the Virtual Observatory. We present
our Virtual-Observatory approach to select an AO-suitable catalog of
X-ray-emitting AGN at redshifts 0.1<z<1.Comment: 4 pages, 5 figures, submitted to "EURO-VO AIDA workshop:
Multiwavelength astronomy and Virtual Observatory", ESAC, Spain, 1-3 Dec.
200
Jaw Dysfunction Is Associated with Neck Disability and Muscle Tenderness in Subjects with and without Chronic Temporomandibular Disorders
Purpose. Tender points in the neck are common in patients with temporomandibular disorders (TMD). However, the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with TMD still needs further investigation. This study investigated the correlation among neck disability, jaw dysfunction, and muscle tenderness in subjects with and without chronic TMD. Participants. Forty females between 19 and 49 years old were included in this study.There were 20 healthy controls and 20 subjects who had chronic TMD and neck disability. Methods. Subjects completed the neck disability index and the limitations of daily functions in TMD questionnaires. Tenderness of the masticatory and cervical muscles was measured using an algometer. Results. The correlation between jaw disability and neck disability was significantly high (� = 0.915, � \u3c 0.05). The correlation between level of muscle tenderness in the masticatory and cervical muscles with jaw dysfunction and neck disability showed fair to moderate correlations (� = 0.32–0.65). Conclusion. High levels of muscle tenderness in upper trapezius and temporalis muscles correlated with high levels of jaw and neck dysfunction. Moreover, high levels of neck disability correlated with high levels of jaw disability.These findings emphasize the importance of considering the neck and its structures when evaluating and treating patients with TMD
Stellar populations of bulges at low redshift
This chapter summarizes our current understanding of the stellar population
properties of bulges and outlines important future research directions.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen
E., Peletier R., Gadotti D., Springer Publishing. 34 pages, 12 figure
Quantitative Morphology of Galaxies from the SDSS I: Luminosity in Bulges and Disks
In the first paper of this series we use the publicly available code Gim2D to
model the r- and i-band images of all galaxies in a magnitude-limited sample of
roughly 1800 morphologically classified galaxies taken from the Sloan Digital
Sky Survey. The model is a concentric superposition of two components, each
with elliptical isophotes with constant flattening and position angle. The disk
luminosity profile is assumed exponential, while the bulge is assumed to have a
de Vaucouleurs or a Sersic profile. We find that the parameters returned by
Gim2D depend little on the waveband or bulge profile used; their formal
uncertainties are usually small. Nevertheless, for bright galaxies the measured
distribution of b/a, the apparent disk flattening, deviates strongly from the
expected uniform distribution, showing that the `disk' identified by the code
frequently corresponds to an intrinsically 3-dimensional structure rather than
to a true thin disk. We correct approximately for this systematic problem using
the observed statistics of the b/a distribution and estimate, as a function of
absolute magnitude, the mean fractions of galaxy light in disks and in `pure
bulge' systems (those with no detectable disk). For the brightest galaxies the
disk light fraction is about 10% and about 80% are `pure bulge' systems. For
faint galaxies most of the light is in disks and we do not detect a `pure
bulge' population. Averaging over the galaxy population as a whole, we find
that 54 \pm 2% of the local cosmic luminosity density at both r and i comes
from disks and 32 \pm 2% from `pure bulge' systems. The remaining 14 \pm 2%
comes from bulges in galaxies with detectable disks.Comment: Submitted to MNRAS (14 pages, 14 figures). For version with higher
quality figures, see
http://www.mpa-garching.mpg.de/~tasca/MNRAS/Morph_paperI.p
Antonio Gramsci’s impact on critical pedagogy
This paper provides an account of Antonio Gramsci’s impact on the area of critical pedagogy. It indicates the Gramscian influence on the thinking of major exponents of the field. It foregrounds Gramsci's ideas and then indicates how they have been taken up by a selection of critical pedagogy exponents who were chosen on the strength of their identification and engagement with Gramsci's ideas, some of them even having written entire essays on Gramsci. The essay concludes with a discussion concerning an aspect of Gramsci's concerns, the question of powerful knowledge, which, in the present author's view, provides a formidable challenge to critical pedagogues.peer-reviewe
Elliptical Galaxies and Bulges of Disk Galaxies: Summary of Progress and Outstanding Issues
This is the summary chapter of a review book on galaxy bulges. Bulge
properties and formation histories are more varied than those of ellipticals. I
emphasize two advances: 1 - "Classical bulges" are observationally
indistinguishable from ellipticals, and like them, are thought to form by major
galaxy mergers. "Disky pseudobulges" are diskier and more actively star-forming
(except in S0s) than are ellipticals. Theys are products of the slow
("secular") evolution of galaxy disks: bars and other nonaxisymmetries move
disk gas toward the center, where it starbursts and builds relatively flat,
rapidly rotating components. This secular evolution is a new area of galaxy
evolution work that complements hierarchical clustering. 2 - Disks of
high-redshift galaxies are unstable to the formation of mass clumps that sink
to the center and merge - an alternative channel for the formation of classical
bulges. I review successes and unsolved problems in the formation of
bulges+ellipticals and their coevolution (or not) with supermassive black
holes. I present an observer's perspective on simulations of dark matter galaxy
formation including baryons. I review how our picture of the quenching of star
formation is becoming general and secure at redshifts z < 1. The biggest
challenge is to produce realistic bulges+ellipticals and disks that overlap
over a factor of 10**3 in mass but that differ from each other as observed over
that whole range. Second, how does hierarchical clustering make so many giant,
bulgeless galaxies in field but not cluster environments? I argue that we rely
too much on AGN and star-formation feedback to solve these challenges.Comment: 46 pages, 10 postscript figures, accepted for publication in Galactic
Bulges, ed. E. Laurikainen, R. F. Peletier, & D. A. Gadotti (New York:
Springer), in press (2015
Morphology and environment of galaxies with disc breaks in the S4G and NIRS0S
We study the surface brightness profiles of disc galaxies in the 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies (S4G) and Ks-band images from the Near-Infrared S0-Sa galaxy Survey (NIRS0S).We particularly connect properties of single exponential (type I), downbending double exponential (type II), and upbending double exponential (type III) disc profile types, to structural components of galaxies by using detailed morphological classifications, and size measurements of rings and lenses. We also study how the local environment of the galaxies affects the profile types by calculating parameters describing the environmental density and the tidal interaction strength. We find that in majority of type II profiles the break radius is connected with structural components such as rings, lenses, and spirals. The exponential disc sections of all three profile types, when considered separately, follow the disc scaling relations. However, the outer discs of type II, and the inner discs of type III, are similar in scalelength to the single exponential discs. Although the different profile types have similar mean environmental parameters, the scalelengths of the type III profiles show a positive correlation with the tidal interaction strength. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.</p
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