5,266 research outputs found
Photometric structure of the peculiar galaxy ESO 235-G58
We present the near-infrared and optical properties of the peculiar galaxy
ESO 235-G58, which resembles a late-type ringed barred spiral seen close to
face-on. However, the apparent bar of ESO 235-G58 is in reality an edge-on disk
galaxy of relatively low luminosity. We have analyzed the light and color
distributions of ESO 235-G58 in the NIR and optical bands and compared them
with the typical properties observed for other morphological galaxy types,
including polar ring galaxies. Similar properties are observed for ESO 235-G58,
polar ring galaxies, and spiral galaxies, which leads us to conclude that this
peculiar system is a polar-ring-related galaxy, characterized by a low inclined
ring/disk structure, as pointed out by Buta & Crocker in an earlier study,
rather than a barred galaxy.Comment: 16 pages, 15 figures, accepted for publication in Astronomy &
Astrophysic
Update of High Resolution (e,e'K^+) Hypernuclear Spectroscopy at Jefferson Lab's Hall A
Updated results of the experiment E94-107 hypernuclear spectroscopy in Hall A
of the Thomas Jefferson National Accelerator Facility (Jefferson Lab), are
presented. The experiment provides high resolution spectra of excitation energy
for 12B_\Lambda, 16N_\Lambda, and 9Li_\Lambda hypernuclei obtained by
electroproduction of strangeness. A new theoretical calculation for
12B_\Lambda, final results for 16N_\Lambda, and discussion of the preliminary
results of 9Li_\Lambda are reported.Comment: 8 pages, 5 figures, submitted to the proceedings of Hyp-X Conferenc
Orthostatic intolerance and autonomic dysfunction following bariatric surgery: A retrospective study and review of the literature
The prevalence and costs of the obesity epidemic and obesity-related conditions, including diabetes mellitus, is consistently increasing worldwide. Bariatric medicine is attempting to address this with weight loss and exercise programmes, and with increasing frequency, various forms of bariatric surgery. There has been considerable success reported after bariatric surgery but not without. We describe 14 patients with orthostatic intolerance (OI) post bariatric surgery. We report on OI (postural dizziness, palpitations and fainting), the results of cardiovascular autonomic testing and the associated and/or causative findings as well as reviewing the literature to consider the possible mechanisms.
Comprehensive autonomic testing revealed that 35.7% (Buchwald et al., 2004) of these patients fulfilled the criteria for the Postural Tachycardia Syndrome (PoTS), 57.1% (Cremieux et al., 2008) had low levels of basal BP and 42.9% (Cammisotto & Bendayan, 2007) patients were presyncopal and 14.3% (Billakanty et al., 2008) experienced syncope. We propose that the incidence of OI post-bariatric surgery is higher than considered, that certain cohorts may be more susceptible to complications, and that further research is needed to identify the prevalence and, ideally anticipate occurrence. With the increasing prevalence of obesity and required clinical interventions, further understanding of the pathophysiological processes causing autonomic dysfunction after bariatric interventions will aid management, which may differ in those with an underlying disposition to autonomic involvement, such as diabetics, in whom such procedures are increasingly used
VEGAS: a VST Early-type GAlaxy Survey. IV. NGC 1533, IC 2038 and IC 2039: an interacting triplet in the Dorado group
This paper focuses on NGC 1533 and the pair IC 2038 and IC 2039 in Dorado a
nearby, clumpy, still un-virialized group. We obtained their surface photometry
from deep OmegaCAM@ESO-VST images in g and r bands. For NGC 1533, we map the
surface brightness down to mag/arcsec and mag/arcsec and out to about . At such faint levels
the structure of NGC 1533 appear amazingly disturbed with clear structural
asymmetry between inner and outer isophotes in the North-East direction. We
detect new spiral arm-like tails in the outskirts, which might likely be the
signature of a past interaction/merging event. Similarly, IC 2038 and IC 2039
show tails and distortions indicative of their ongoing interaction. Taking
advantages of deep images, we are able to detect the optical counterpart to the
HI gas. The analysis of the new deep data suggests that NGC 1533 had a complex
history made of several interactions with low-mass satellites that generated
the star-forming spiral-like structure in the inner regions and are shaping the
stellar envelope. In addition, the VST observations show that also the two less
luminous galaxies, IC 2038 and IC 2039, are probably interacting each-other
and, in the past, IC 2038 could have also interacted with NGC 1533, which
stripped away gas and stars from its outskirts. The new picture emerging from
this study is of an interacting triplet, where the brightest galaxy NGC 1533
has ongoing mass assembly in the outskirts.Comment: Accepted for publication in The Astronomical Journal. High-resolution
version of paper is available at the following link:
https://www.dropbox.com/preview/VEGAS_IV.pdf?role=persona
Polar Ring Galaxies and the Tully Fisher relation: implications for the dark halo shape
We have investigated the Tully-Fisher relation for Polar Ring Galaxies
(PRGs), based on near infrared, optical and HI data available for a sample of
these peculiar objects. The total K-band luminosity, which mainly comes from
the central host galaxy, and the measured HI linewidth at 20% of the peak line
flux density, which traces the potential in the polar plane, place most polar
rings of the sample far from the Tully-Fisher relation defined for spiral
galaxies, with many PRGs showing larger HI linewidths than expected for the
observed K band luminosity. This result is confirmed by a larger sample of
objects, based on B-band data. This observational evidence may be related to
the dark halo shape and orientation in these systems, which we study by
numerical modeling of PRG formation and dynamics: the larger rotation
velocities observed in PRGs can be explained by a flattened polar halo, aligned
with the polar ring.Comment: 22 pages, 8 postscript figures, accepted for publication in
Astrophysical Journa
Hickson 62.I. Kinematics of NGC4778
Detailed studies of the photometric and kinematical properties of compact
groups of galaxies are crucial to understand the physics of galaxy interactions
and to shed light on some aspects of galaxy formation and evolution. In this
paper we present a kinematical and photometrical study of a member, NGC4778, of
the nearest (z=0.0137) compact group: Hickson 62.
Aims: The aim of this work was to investigate the existence of kinematical
anomalies in the brightest group member, NGC4778 in order to constrain the
dynamical status and the formation history of the group.
Methods: We used long-slit spectra obtained with FORS1 at VLT, to measure
line-of-sight velocity distributions by means of the Fourier Correlation
Quotient method, and to derive the galaxy rotation curve and velocity
dispersion profile.
Results: Our analysis reveals that Hickson 62a, also known as NGC4778, is an
S0 galaxy with kinematical and morphological peculiarities, both in its central
regions (r < 5'') and in the outer halo. In the central regions, the rotation
curve shows the existence of a kinematically decoupled stellar component,
offset with respect to the photometric center. In the outer halo we find an
asymmetric rotation curve and a velocity dispersion profile showing a rise on
the SW side, in direction of the galaxy NGC4776.
Conclusions: The nuclear counterrotation, the distorted kinematics in the
outer halo and the X-ray properties of the group suggest that NGC4778 may be
the product of a recent minor merger, more reliable with a small late-type
galaxy.Comment: 18 pages, 8 figures, accepted for pubblication in Astronomy and
Astrophysic
The Fornax Deep Survey with VST. VIII. Connecting the accretion history with the cluster density
This work is based on deep multi-band (g, r, i) data from the Fornax Deep
Survey with VST. We analyse the surface brightness profiles of the 19 bright
ETGs inside the virial radius of the Fornax cluster. The main aim of this work
is to identify signatures of accretion onto galaxies by studying the presence
of outer stellar halos, and understand their nature and occurrence. Our
analysis also provides a new and accurate estimate of the intra-cluster light
inside the virial radius of Fornax. We performed multi-component fits to the
azimuthally averaged surface brightness profiles available for all sample
galaxies. This allows to quantify the relative weight of all components in the
galaxy structure that contribute to the total light. In addition, we derived
the average g-i colours in each component identified by the fit, as well as the
azimuthally averaged g-i colour profiles, to correlate them with the stellar
mass of each galaxy and the location inside the cluster. We find that in the
most massive and reddest ETGs the fraction of light in, probably accreted,
halos is much larger than in the other galaxies. Less-massive galaxies have an
accreted mass fraction lower than 30%, bluer colours and reside in the
low-density regions of the cluster. Inside the virial radius of the cluster,
the total luminosity of the intra-cluster light, compared with the total
luminosity of all cluster members, is about 34%. Inside the Fornax cluster
there is a clear correlation between the amount of accreted material in the
stellar halos of galaxies and the density of the environment in which those
galaxies reside. By comparing this quantity with theoretical predictions and
previous observational estimates, there is a clear indication that the driving
factor for the accretion process is the total stellar mass of the galaxy, in
agreement with the hierarchical accretion scenario.Comment: 18 pages, 10 figures. Accepted for publication in A&
Correction of multiple canine impactions by mixed straightwire and cantilever mechanics: a case report.
Background. This case report describes the orthodontic treatment of a woman, aged 17 years, with a permanent dentition, brachyfacial typology, Angle Class I, with full impaction of two canines (13,33), and a severe ectopy of the maxillary left canine. Her main compliant was the position of the ectopic teeth. Methods. Straightwire fixed appliances, together with cantilever mechanics, were used to correct the impaired occlusion and to obtain an ideal torque control. Results and Conclusion. The treatment objectives were achieved in 26 months of treatment. The impactions were fully corrected with an optimal torque. The cantilever mechanics succeeded in obtaining tooth repositioning in a short lapse of time. After treatment, the dental alignment was stable
- …
