253 research outputs found
Hot water irrigation as treatment for intractable posterior epistaxis in an out-patient setting
The management of intractable posterior epistaxis is challenging for any physician. Nasal packing, often combined with use of an endonasal balloon system, is painful for the patient, and torturous to maintain for two to three days. If conservative treatment fails, the most commonly used treatment options are currently invasive procedures such as endoscopic coagulation of bleeding arteries, external ligation and, rarely, embolisation. This paper describes a simple, non-invasive technique of treating posterior epistaxis with hot water irrigation. Technical information is presented, and the benefits of the method are discusse
Anatomical variation of the extracranial course of the optic nerve in the floor of the sphenoid sinus: first reported case
Abstract Objective: We report a unique case of anatomical variation of the extracranial course of the optic nerve running in the floor of the sphenoid sinus. Method: Clinical and radiological findings are presented. Results: A 39-year-old woman with Turner syndrome presented with severe headache associated with visual disturbances. Magnetic resonance imaging revealed a mass presumed to be a sella meningioma. Computed tomography of the paranasal sinuses was undertaken to help plan surgical removal via an endoscopic trans-sphenoidal approach; this scan revealed an atypical extracranial course of the optic nerve, running in the floor of the sphenoid sinu
B and I-band optical micro-variability observations of the BL Lac objects S5 2007+777 and 3C371
We have observed S5 2007+777 and 3C371 in the B and I bands for 13 and 8
nights, respectively, during various observing runs in 2001, 2002 and 2004. The
observations resulted in almost evenly sampled light curves, 6-9 hours long. We
do not detect any flares within the observed light curves, but we do observe
small amplitude, significant variations, in both bands, on time scales of hours
and days. The average variability amplitude on time scales of minutes/hours is
2.5% and 1-1.5% in the case of S5 2007+777 and 3C371, respectively. The average
amplitudes increase to 5-12% and 4-6%, respectively, on time scales of days. We
find that the B and I band variations are highly correlated, on both short and
long time scales. During the 2004 observations, which resulted in the longest
light curves, we observe two well defined flux-decay and rising trends in the
light curves of both objects. When the flux decays, we observe significant
delays, with the B band flux decaying faster than the flux in the I band. As a
result, we also observe significant, flux related spectral variations as well.
The flux-spectral relation is rather complicated, with loop-like structures
forming during the flux evolution. The presence of spectral variations imply
that the observed variability is not caused by geometric effects. On the other
hand, our results are fully consistent with the hypothesis that the observed
variations are caused by perturbations which affect different regions in the
jet of the sources.Comment: Accepted for publication in Astronomy and Astrophysic
Internal kinematics of spiral galaxies in distant clusters. Part II. Observations and data analysis
We have conducted an observing campaign with FORS at the ESO-VLT to explore
the kinematical properties of spiral galaxies in distant galaxy clusters. Our
main goal is to analyse transformation- and interaction processes of disk
galaxies within the special environment of clusters as compared to the
hierarchical evolution of galaxies in the field. Spatially resolved MOS-spectra
have been obtained for seven galaxy clusters at 0.3<z<0.6 to measure rotation
velocities of cluster members. For three of the clusters, Cl0303+17, Cl0413-65,
and MS1008-12, for which we presented results including a TF-diagram in Ziegler
et al. 2003, we describe here in detail the observations and data analysis.
Each of them was observed with two setups of the standard FORS MOS-unit.With
typical exposure times of >2 hours we reach an S/N>5 in the emission lines
appropriate for the deduction of the galaxies' internal rotation velocities
from [OII], Hbeta, or [OIII] profiles. Preselection of targets was done on the
basis of available redshifts as well as from photometric and morphological
information gathered from own observations, archive data, and from the
literature. Emphasis was laid on the definition of suitable setups to avoid the
typical restrictions of the standard MOS unit for this kind of observations. In
total we assembled spectra of 116 objects of which 50 turned out to be cluster
members. Position velocity diagrams, finding charts as well as tables with
photometric, spectral, and structural parameters of individual galaxies are
presented.Comment: 18 pages, 6 figures, accepted for publication in Astronomy and
Astrophysics. A version with full resolution figures can be downloaded from
http://www.uni-sw.gwdg.de/~vwgroup/publications.htm
Constraining Scale-Dependent Non-Gaussianity with Future Large-Scale Structure and the CMB
We forecast combined future constraints from the cosmic microwave background
and large-scale structure on the models of primordial non-Gaussianity. We study
the generalized local model of non-Gaussianity, where the parameter f_NL is
promoted to a function of scale, and present the principal component analysis
applicable to an arbitrary form of f_NL(k). We emphasize the complementarity
between the CMB and LSS by using Planck, DES and BigBOSS surveys as examples,
forecast constraints on the power-law f_NL(k) model, and introduce the figure
of merit for measurements of scale-dependent non-Gaussianity.Comment: 28 pages, 8 figures, 2 tables; v2: references update
SMASH 1 : A VERY FAINT GLOBULAR CLUSTER DISRUPTING in the OUTER REACHES of the LMC?
We present the discovery of a very faint stellar system, SMASH 1, that is potentially a satellite of the Large Magellanic Cloud. Found within the Survey of the Magellanic Stellar History (SMASH), SMASH 1 is a compact (rh=9.1-3.4+5.9pc) and very low luminosity (Mv=-1.0±0.9,Lv=102.3±0.4Lâ ) stellar system that is revealed by its sparsely populated main sequence and a handful of red giant branch candidate member stars. The photometric properties of these stars are compatible with a metal-poor ([Fe/H]=-2.2) and old (13 Gyr) isochrone located at a distance modulus of âŒ18.8, i.e., a distance of . Situated at 11.°3 from the LMC in projection, its three-dimensional distance from the Cloud is 13 kpc, consistent with a connection to the LMC, whose tidal radius is at least . Although the nature of SMASH 1 remains uncertain, its compactness favors it being a stellar cluster and hence dark-matter free. If this is the case, its dynamical tidal radius is only âČ19 pc at this distance from the LMC, and smaller than the system's extent on the sky. Its low luminosity and apparent high ellipticity (Ï”=0.62-0.21+0.17) with its major axis pointing toward the LMC may well be the tell-tale sign of its imminent tidal demise.Peer reviewe
Rapid optical variability of TeV blazars
In this first systematic attempt to characterise the intranight optical
variability (INOV) of TeV detected blazars, we have monitored a well defined
set of 9 TeV blazars on total 26 nights during 2004-2010. In this R (or V)-band
monitoring programme only one blazar was monitored per night for a minimum
duration of 4 hours. Using the CCD, an INOV detection threshold of ~ 1-2 % was
achieved in the densely sampled DLCs. We have further expanded the sample by
including another 13 TeV blazars from literature. This enlarged sample of 22
TeV blazars, monitored on a total of 116 nights (including 55 nights newly
reported here), has enabled us to arrive at the first estimate of the INOV duty
cycle of TeV detected blazars. Applying the C-test, the INOV DC is found to be
59 %, which decreases to 47 % if only INOV fractional amplitudes above 3 % are
considered. These observations also permit, for the first time, a comparison of
the INOV characteristics of the two major subclasses of TeV detected BL Lacs,
namely LBLs and HBLs, for which we find the INOV DCs to be ~ 63 % and ~ 38 %,
respectively. This demonstrates that the INOV differential between LBLs and
HBLs persists even when only their TeV detected subsets are considered. Despite
dense sampling, the intranight light curves of the 22 TeV blazars have not
revealed even a single feature on time scale substantially shorter than 1 hour,
even though the inner jets of TeV blazars are believed to have exceptionally
large bulk Lorentz factors (and correspondingly stronger time compression). An
intriguing feature, clearly detected in the light curve of the HBL J1555+1111,
is a 4 per cent `dip' on a 1 hour timescale. This unique feature could have
arisen from absorption in a dusty gas cloud, occulting a superluminally moving
optical knot in the parsec scale jet of this relatively luminous BL Lacs
object.Comment: 39 pages, 3 figures, accepted for publication in MNRA
AN ULTRA-FAINT GALAXY CANDIDATE DISCOVERED in EARLY DATA from the MAGELLANIC SATELLITES SURVEY
We report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of the Magellanic Satellites Survey (MagLiteS). MagLiteS J0644-5953 (Pictor II or Pic II) is a low surface brightness (Ό = 28.5+1 -1 mag arcsec-2 within its half-light radius) resolved overdensity of old and metal-poor stars located at a heliocentric distance of 45+5 -4 kpc. The physical size (r1/2 = 46+15 -11) and low luminosity (Mv = -3.2+0.4 -0.5 mag) of this satellite are consistent with the locus of spectroscopically confirmed ultra-faint galaxies. MagLiteS J0644-5953 (Pic II) is located 11.3+3.1 -0.9 kpc from the Large Magellanic Cloud (LMC), and comparisons with simulation results in the literature suggest that this satellite was likely accreted with the LMC. The close proximity of MagLiteS J0644-5953 (Pic II) to the LMC also makes it the most likely ultra-faint galaxy candidate to still be gravitationally bound to the LMC.Peer reviewe
HST/ACS observations of shell galaxies: inner shells, shell colours and dust
AIM:Learn more about the origin of shells and dust in early type galaxies.
METHOD: V-I colours of shells and underlying galaxies are derived, using HST
Advanced Camera for Surveys (ACS) data. A galaxy model is made locally in
wedges and subtracted to determine shell profiles and colours. We applied
Voronoi binning to our data to get smoothed colour maps of the galaxies.
Comparison with N-body simulations from the literature gives more insight to
the origin of the shell features. Shell positions and dust characteristics are
inferred from model galaxy subtracted images. RESULT: The ACS images reveal
shells well within the effective radius in some galaxies (at 1.7 kpc in the
case of NGC 5982). In some cases, strong nuclear dust patches prevent detection
of inner shells. Most shells have colours which are similar to the underlying
galaxy. Some inner shells are redder than the galaxy. All six shell galaxies
show out of dynamical equilibrium dust features, like lanes or patches, in
their central regions. Our detection rate for dust in the shell ellipticals is
greater than that found from HST archive data for a sample of normal early-type
galaxies, at the 95% confidence level. CONCLUSIONS: The merger model describes
better the shell distributions and morphologies than the interaction model. Red
shell colours are most likely due to the presence of dust and/or older stellar
populations. The high prevalence and out of dynamical equilibrium morphologies
of the central dust features point towards external influences being
responsible for visible dust features in early type shell galaxies. Inner
shells are able to manifest themselves in relatively old shell systems.Comment: accepted by A&A; 36 Figures, 25 pages. A version with full resolution
Figures can be found here: http://www.astro.rug.nl/~sikkema/shells.p
The Hubble Space Telescope Cluster Supernova Survey: V. Improving the Dark Energy Constraints Above z>1 and Building an Early-Type-Hosted Supernova Sample
We present ACS, NICMOS, and Keck AO-assisted photometry of 20 Type Ia
supernovae SNe Ia from the HST Cluster Supernova Survey. The SNe Ia were
discovered over the redshift interval 0.623 < z < 1.415. Fourteen of these SNe
Ia pass our strict selection cuts and are used in combination with the world's
sample of SNe Ia to derive the best current constraints on dark energy. Ten of
our new SNe Ia are beyond redshift , thereby nearly doubling the
statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed
analysis corrects for the recently identified correlation between SN Ia
luminosity and host galaxy mass and corrects the NICMOS zeropoint at the count
rates appropriate for very distant SNe Ia. Adding these supernovae improves the
best combined constraint on the dark energy density \rho_{DE}(z) at redshifts
1.0 < z < 1.6 by 18% (including systematic errors). For a LambdaCDM universe,
we find \Omega_\Lambda = 0.724 +0.015/-0.016 (68% CL including systematic
errors). For a flat wCDM model, we measure a constant dark energy
equation-of-state parameter w = -0.985 +0.071/-0.077 (68% CL). Curvature is
constrained to ~0.7% in the owCDM model and to ~2% in a model in which dark
energy is allowed to vary with parameters w_0 and w_a. Tightening further the
constraints on the time evolution of dark energy will require several
improvements, including high-quality multi-passband photometry of a sample of
several dozen z>1 SNe Ia. We describe how such a sample could be efficiently
obtained by targeting cluster fields with WFC3 on HST.Comment: 27 pages, 11 figures. Submitted to ApJ. This first posting includes
updates in response to comments from the referee. See
http://www.supernova.lbl.gov for other papers in the series pertaining to the
HST Cluster SN Survey. The updated supernova Union2.1 compilation of 580 SNe
is available at http://supernova.lbl.gov/Unio
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