2,403 research outputs found
Outflows of hot molecular gas in ultra-luminous infra-red galaxies mapped with VLT-SINFONI
We present the detection and morphological characterization of hot molecular
gas outflows in nearby ultra-luminous infrared galaxies, using the near-IR
integral-field spectrograph SINFONI on the VLT. We detect outflows observed in
the 2.12 micron H 1-0 S(1) line for three out of four ULIRGs analyzed;
IRAS 12112+0305, 14348-1447, and 22491-1808. The outflows are mapped on scales
of 0.7-1.6 kpc, show typical outflow velocities of 300-500 km/s, and appear to
originate from the nuclear region. The outflows comprise hot molecular gas
masses of ~6-8x10 M(sun). Assuming a hot-to-cold molecular gas mass ratio
of 6x10, as found in nearby luminous IR galaxies, the total (hot+cold)
molecular gas mass in these outflows is expected to be ~1x10 M(sun). This
translates into molecular mass outflow rates of ~30-85 M(sun)/yr, which is a
factor of a few lower than the star formation rate in these ULIRGs. In
addition, most of the outflowing molecular gas does not reach the escape
velocity of these merger systems, which implies that the bulk of the outflowing
molecular gas is re-distributed within the system and thus remains available
for future star formation. The fastest H outflow is seen in the
Compton-thick AGN of IRAS 14348-1447, reaching a maximum outflow velocity of
~900 km/s. Another ULIRG, IRAS 17208-0014, shows asymmetric H line
profiles different from the outflows seen in the other three ULIRGs. We discuss
several alternative explanations for its line asymmetries, including a very
gentle galactic wind, internal gas dynamics, low-velocity gas outside the disk,
or two superposed gas disks. We do not detect the hot molecular counterpart to
the outflow previously detected in CO(2-1) in IRAS 17208-0014, but we note that
our SINFONI data are not sensitive enough to detect this outflow if it has a
small hot-to-cold molecular gas mass ratio of < 9x10.Comment: Accepted for publication in A&A (11 pages, 10 figures
High spatial resolution and high contrast optical speckle imaging with FASTCAM at the ORM
In this paper, we present an original observational approach, which combines,
for the first time, traditional speckle imaging with image post-processing to
obtain in the optical domain diffraction-limited images with high contrast
(1e-5) within 0.5 to 2 arcseconds around a bright star. The post-processing
step is based on wavelet filtering an has analogy with edge enhancement and
high-pass filtering. Our I-band on-sky results with the 2.5-m Nordic Telescope
(NOT) and the lucky imaging instrument FASTCAM show that we are able to detect
L-type brown dwarf companions around a solar-type star with a contrast DI~12 at
2" and with no use of any coronographic capability, which greatly simplifies
the instrumental and hardware approach. This object has been detected from the
ground in J and H bands so far only with AO-assisted 8-10 m class telescopes
(Gemini, Keck), although more recently detected with small-class telescopes in
the K band. Discussing the advantage and disadvantage of the optical regime for
the detection of faint intrinsic fluxes close to bright stars, we develop some
perspectives for other fields, including the study of dense cores in globular
clusters. To the best of our knowledge this is the first time that high
contrast considerations are included in optical speckle imaging approach.Comment: Proceedings of SPIE conference - Ground-based and Airborne
Instrumentation for Astronomy III (Conference 7735), San Diego 201
Luminescence study of thermal treated and laser irradiated Bi_12GeO_20 and Bi_12SiO_20 crystals
Changes on the defect structure of Bi12GeO20 (BGO) and Bi12SiO20 (BSO) crystals induced by thermal treatments and laser irradiation have been studied by means of cathodoluminescence in the scanning electron microscope. The results have been compared to those previously reported for untreated and electron irradiated samples and recombination mechanisms responsible for some of the observed luminescence bands are discussed. Annealing of EGO samples causes the appearance of a new luminescence band at about 390 nm. The centers responsible for this band decorate the deformation slip bands in quenched EGO as observed in the cathodoluminescence images. The emission observed in BSO in the same spectral range is quenched during the annealing treatment. The annealing induced reduction of Bi ions to metallic Bi appears to be related to the quenching of a band at 640 nm observed in untreated samples
Basal and inducible anti-inflammatory epoxygenase activity in endothelial cells
The roles of CYP lipid-metabolizing pathways in endothelial cells are poorly understood. Human endothelial cells expressed CYP2J2 and soluble epoxide hydrolase (sEH) mRNA and protein. The TLR-4 agonist LPS (1 ÎŒg/ml; 24 h) induced CYP2J2 but not sEH mRNA and protein. LCâMS/MS analysis of the stable commonly used human endothelial cell line EA.Hy926 showed active epoxygenase and epoxide hydrolase activity: with arachidonic acid (stable epoxide products 5,6-DHET, and 14,15-DHET), linoleic acid (9,10-EPOME and 12,13-EPOME and their stable epoxide hydrolase products 9,10-DHOME and 12,13-DHOME), docosahexaenoic acid (stable epoxide hydrolase product 19,20-DiHDPA) and eicosapentaenoic acid (stable epoxide hydrolase product 17,18-DHET) being formed. Inhibition of epoxygenases using either SKF525A or MS-PPOH induced TNFα release, but did not affect LPS, IL-1ÎČ, or phorbol-12-myristate-13-acetate (PMA)-induced TNFα release. In contrast, inhibition of soluble epoxide hydrolase by AUDA or TPPU inhibited basal, LPS, IL-1ÎČ and PMA induced TNFα release, and LPS-induced NFÎșB p65 nuclear translocation. In conclusion, human endothelial cells contain a TLR-4 regulated epoxygenase CYP2J2 and metabolize linoleic acid > eicosapentaenoic acid > arachidonic acid > docosahexaenoic acid to products with anti-inflammatory activity
Ectoparasitosis por ĂĄcaro de la cosecha
Se describe la parasitaciĂłn en perro por NeotrombĂcula autumnalĂș (ĂĄcaro de la cosecha) en cuatro casos clĂnicos.We describe four clinical cases of parasitic disease in dogs caused by Neotrombicula autumnalis (Harvest Chigger)
Study of pinholes and nanotubes in AlInGaN films by cathodoluminescence and atomic force microscopy
Cathodoluminescence (CL) in the scanning electron microscope and atomic force microscopy (AFM) have been used to study the formation of pinholes in tensile and compressively strained AlInGaN films grown on Al2O3 substrates by plasma-induced molecular beam epitaxy. Nanotubes, pits, and V-shaped pinholes are observed in a tensile strained sample. CL images show an enhanced emission around the pits and a lower intensity at the V-shaped pinholes. Rounded pinholes appear in compressively strained samples in island-like regions with higher In concentration. The grain structure near the pinholes is resolved by AFM. (C) 2004 American Institute of Physics
Spatially Resolved [FeII] 1.64 \mu m Emission in NGC 5135. Clues for Understanding the Origin of the Hard X-rays in Luminous Infrared Galaxies
Spatially resolved near-IR and X-ray imaging of the central region of the
Luminous Infrared Galaxy NGC 5135 is presented. The kinematical signatures of
strong outflows are detected in the [FeII]1.64 \mu m emission line in a compact
region at 0.9 kpc from the nucleus. The derived mechanical energy release is
consistent with a supernova rate of 0.05-0.1 yr. The apex of the
outflowing gas spatially coincides with the strongest [FeII] emission peak and
with the dominant component of the extranuclear hard X-ray emission. All these
features provide evidence for a plausible direct physical link between
supernova-driven outflows and the hard X-ray emitting gas in a LIRG. This
result is consistent with model predictions of starbursts concentrated in small
volumes and with high thermalization efficiencies. A single high-mass X-ray
binary (HMXB) as the major source of the hard X-ray emission although not
favoured, cannot be ruled out. Outside the AGN, the hard X-ray emission in NGC
5135 appears to be dominated by the hot ISM produced by supernova explosions in
a compact star-forming region, and not by the emission due to HMXB. If this
scenario is common to U/LIRGs, the hard X-rays would only trace the most
compact (< 100 pc) regions with high supernova and star formation densities,
therefore a lower limit to their integrated star formation. The SFR derived in
NGC 5135 based on its hard X-ray luminosity is a factor of two and four lower
than the values obtained from the 24 \mu m and soft X-ray luminosities,
respectively.Comment: Accepted for Publication in ApJ, 18 pages, 2 figure
High contrast optical imaging of companions: the case of the brown dwarf binary HD-130948BC
High contrast imaging at optical wavelengths is limited by the modest
correction of conventional near-IR optimized AO systems.We take advantage of
new fast and low-readout-noise detectors to explore the potential of fast
imaging coupled to post-processing techniques to detect faint companions to
stars at small separations. We have focused on I-band direct imaging of the
previously detected brown dwarf binary HD130948BC,attempting to spatially
resolve the L2+L2 benchmark system. We used the Lucky-Imaging instrument
FastCam at the 2.5-m Nordic Telescope to obtain quasi diffraction-limited
images of HD130948 with ~0.1" resolution.In order to improve the detectability
of the faint binary in the vicinity of a bright (I=5.19 \pm 0.03) solar-type
star,we implemented a post-processing technique based on wavelet transform
filtering of the image which allows us to strongly enhance the presence of
point-like sources in regions where the primary halo dominates. We detect for
the first time the BD binary HD130948BC in the optical band I with a SNR~9 at
2.561"\pm 0.007" (46.5 AU) from HD130948A and confirm in two independent
dataset that the object is real,as opposed to time-varying residual speckles.We
do not resolve the binary, which can be explained by astrometric results
posterior to our observations that predict a separation below the NOT
resolution.We reach at this distance a contrast of dI = 11.30 \pm 0.11, and
estimate a combined magnitude for this binary to I = 16.49 \pm 0.11 and a I-J
colour 3.29 \pm 0.13. At 1", we reach a detectability 10.5 mag fainter than the
primary after image post-processing. We obtain on-sky validation of a technique
based on speckle imaging and wavelet-transform processing,which improves the
high contrast capabilities of speckle imaging.The I-J colour measured for the
BD companion is slightly bluer, but still consistent with what typically found
for L2 dwarfs(~3.4-3.6).Comment: accepted in A\&
Lucky Imaging Adaptive Optics of the brown dwarf binary GJ569Bab
The potential of combining Adaptive Optics (AO) and Lucky Imaging (LI) to
achieve high precision astrometry and differential photometry in the optical is
investigated by conducting observations of the close 0\farcs1 brown dwarf
binary GJ569Bab. We took 50000 -band images with our LI instrument FastCam
attached to NAOMI, the 4.2-m William Herschel Telescope (WHT) AO facility. In
order to extract the most of the astrometry and photometry of the GJ569Bab
system we have resorted to a PSF fitting technique using the primary star
GJ569A as a suitable PSF reference which exhibits an -band magnitude of
. The AO+LI observations at WHT were able to resolve the binary
system GJ569Bab located at 4\farcs 92 \pm 0\farcs05 from GJ569A. We measure a
separation of mas and -band magnitudes of
and and colors of 2.720.08 and 2.830.08 for
the Ba and Bb components, respectively. Our study rules out the presence of any
other companion to GJ569A down to magnitude I 17 at distances larger than
1\arcsec. The colors measured are consistent with M8.5-M9 spectral types
for the Ba and Bb components. The available dynamical, photometric and
spectroscopic data are consistent with a binary system with Ba being slightly
(10-20%) more massive than Bb. We obtain new orbital parameters which are in
good agreement with those in the literature.Comment: 13 pages, 9 figures, 7 tables, in press in MNRA
The Cutaneous Biopsy for the Diagnosis of Peripheral Neuropathies: Meissnerâs Corpuscles and Merkelâs Cells
Cutaneous biopsy is a complementary method, alternative to peripheral nerve biopsy, for the analysis of nerve involvement in peripheral neuropathies, systemic diseases, and several pathologies of the central nervous system. Most of these neuropathological studies were focused on the intraepithelial nerve fibers (thin-myelinated AÎŽ fibers and unmyelinated C fibers), and few studies investigated the variations in dermal innervation, that is, large myelinated fibers, Merkelâs cell-neurite complexes, and Meissnerâs corpuscles. Here, we updated and summarized the current data about the quantitative and qualitative changes that undergo MCs and MkCs in peripheral neuropathies. Moreover, we provide a comprehensive rationale to include MCs in the study of cutaneous biopsies when analyzing the peripheral neuropathies and aim to provide a protocol to study them
- âŠ