707 research outputs found
Anterior segment optical coherence tomography changes with introduction and discontinuation of tamsulosin
published_or_final_versio
Massa específica foliar de Maytenus ilicifolia Mart. ex Reiss. em função de variáveis ambientais.
Resumo
Variação dos teores foliares de silício, taninos e lignina, em Maytenus ilicifolia Martius (Espinheira-santa), em função de variáveis ambientais e genéticas.
Organizado por Patricia Póvoa de Mattos, Celso Garcia Auer, Rejane Stumpf Sberze, Katia Regina Pichelli e Paulo César Botosso
Efeito da bracatinga (Mimosa scabrella) na produção de matéria seca de pastagem sob sistema silvipastorial.
Edición de las Memorias de la 22a. Reunión ALPA, 2011, Montevideo. E68 Poster
Mid-Infrared Imaging of NGC 6334 I
We present high-resolution (<0.5") mid-infrared Keck II images of individual
sources in the central region of NGC 6334 I. We compare these images to images
at a variety of other wavelengths from the near infrared to cm radio continuum
and speculate on the nature of the NGC 6334 I sources. We assert that the
cometary shape of the UCHII region here, NGC 6334 F, is due to a champagne-like
flow from a source on the edge of a molecular clump and not a due to a bow
shock caused by the supersonic motion of the UCHII region through the
interstellar medium. The mid-infrared emission in concentrated into an arc of
dust that define the boundary between the UCHII region and the molecular clump.
This dust arc contains a majority of the masers in the region. We discuss the
nature of the four near-infrared sources associated with IRS-I 1, and suggest
that one of the sources, IRS1E, is responsible for the heating and ionizing of
the UCHII region and the mid-infrared dust arc. Infrared source IRS-I 2, which
has been thought to be a circumstellar disk associated with a linear
distribution of methanol masers, is found not to be directly coincident with
the masers and elongated at a much different position angle. IRS-I 3 is found
to be a extended source of mid-infrared emission coming from a cluster of young
dusty sources seen in the near-infrared.Comment: Accepted for publication by the Astrophysical Journal, 27 pages, 9
figure
Mid-Infrared T-ReCS Spectroscopy of Local LIRGs
We present T-ReCS high spatial resolution N-band (8-13 micron) spectroscopy of the central regions (a few kpc) of 3 local LIRGs. The nuclear spectra show deep 9.7 micron silicate absorption feature and the high ionization [SIV]10.5 micron emission line, consistent with their optical classification as AGN. The two LIRGs with unresolved mid-IR emission do not show PAH emission at 11.3 micron in their nuclear spectra. The spatially resolved mid-IR spectroscopy of NGC 5135 allows us to separate out the spectra of the Seyfert nucleus, an HII region, and the diffuse region between them on scales of less than 2.5 arcsec ~ 600 pc. The diffuse region spectrum is characterized by strong PAH emission with almost no continuum, whereas the HII region shows PAH emission with a smaller equivalent width as well as [NeII]12.8 micron line
Crystalline Silicate Emission in the Protostellar Binary Serpens--SVS20
We present spatially resolved mid-infrared spectroscopy of the class
I/flat-spectrum protostellar binary system SVS20 in the Serpens cloud core. The
spectra were obtained with the mid-infrared instrument T-ReCS on Gemini-South.
SVS20-South, the more luminous of the two sources, exhibits a mid-infrared
emission spectrum peaking near 11.3 \micron, while SVS20-North exhibits a
shallow amorphous silicate absorption spectrum with a peak optical depth of
. After removal of the the line-of-sight extinction by the
molecular common envelope, the ``protostar-only'' spectra are found to be
dominated by strong amorphous olivine emission peaking near 10 \micron. We also
find evidence for emission from crystalline forsterite and enstatite associated
with both SVS20-S and SVS20-N. The presence of crystalline silicate in such a
young binary system indicates that the grain processing found in more evolved
HAeBe and T Tauri pre-main sequence stars likely begins at a relatively young
evolutionary stage, while mass accretion is still ongoing.Comment: Accepted for publication by The Astrophysical Journa
Observations of Massive Star Forming Regions with Water Masers: Mid-Infrared Imaging
We present here a mid-infrared imaging survey of 26 sites of water maser
emission. Observations were obtained at the InfraRed Telescope Facility 3-m
telescope with the University of Florida mid-infrared imager/spectrometer
OSCIR, and the JPL mid-infrared camera MIRLIN. The main purpose of the survey
was to explore the relationship between water masers and the massive star
formation process. It is generally believed that water masers predominantly
trace outflows and embedded massive stellar objects, but may also exist in
circumstellar disks around young stars. We investigate each of these
possibilities in light of our mid-infrared imaging. We find that mid-infrared
emission seems to be more closely associated with water and OH maser emission
than cm radio continuum emission from UC HII regions. We also find from the
sample of sources in our survey that, like groups of methanol masers, both
water and OH masers have a proclivity for grouping into linear or elongated
distributions. We conclude that the vast majority of linearly distributed
masers are not tracing circumstellar disks, but outflows and shocks instead.Comment: 49 pages; 23 figures; To appear in February 2005 ApJS; To download a
version with better quality figures, go to
http://www.ctio.noao.edu/~debuizer
A Search for Mid-Infrared Emission from Hot Molecular Core Candidates
We present here mid-infrared images of seven sites of water maser emission
thought to be associated with the hot molecular core (HMC) phase of massive
star formation. Observations were obtained at the NASA InfraRed Telescope
Facility 3-m, the Gemini 8-m, and Keck II 10-m telescopes. We have detected
mid-infrared sources at the locations of two HMC candidates, G11.94-0.62 and
G45.07-0.13. We observed G19.61-0.23 and G34.26+0.15, each of which have HMCs
previously detected in the mid-infrared. We did not detect mid-infrared
emission from either HMC source, and we place new upper limits on the
mid-infrared flux densities for these HMCs that are much lower than their
previously reported flux densities. We were able to obtain extremely accurate
astrometry for our mid-infrared images of G9.62+0.19, and conclude that the
mid-infrared emission thought to be coming from the HMC in this field is in
fact coming from a different source altogether.Comment: 19 pages, 17 figures, to appear in ApJ. Also available at
http://www.ctio.noao.edu/~debuizer
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