3,222 research outputs found
A 33 GHz Survey of Local Major Mergers: Estimating the Sizes of the Energetically Dominant Regions from High Resolution Measurements of the Radio Continuum
We present Very Large Array observations of the 33 GHz radio continuum
emission from 22 local ultraluminous and luminous infrared (IR) galaxies
(U/LIRGs). These observations have spatial (angular) resolutions of 30--720 pc
(0.07"-0.67") in a part of the spectrum that is likely to be optically thin.
This allows us to estimate the size of the energetically dominant regions. We
find half-light radii from 30 pc to 1.7 kpc. The 33 GHz flux density correlates
well with the IR emission, and we take these sizes as indicative of the size of
the region that produces most of the energy. Combining our 33 GHz sizes with
unresolved measurements, we estimate the IR luminosity and star formation rate
per area, and the molecular gas surface and volume densities. These quantities
span a wide range (4 dex) and include some of the highest values measured for
any galaxy (e.g., ). At least sources appear Compton thick (). Consistent with previous work, contrasting these data
with observations of normal disk galaxies suggests a nonlinear and likely
multi-valued relation between SFR and molecular gas surface density, though
this result depends on the adopted CO-to-H conversion factor and the
assumption that our 33 GHz sizes apply to the gas. 11 sources appear to exceed
the luminosity surface density predicted for starbursts supported by radiation
pressure and supernovae feedback, however we note the need for more detailed
observations of the inner disk structure. U/LIRGs with higher surface
brightness exhibit stronger [{\sc Cii}] 158m deficits, consistent with the
suggestion that high energy densities drive this phenomenon.Comment: 32 pages, 11 figures, 7 tables. Accepted for publication in Ap
J-PLUS: A wide-field multi-band study of the M15 globular cluster. Evidence of multiple stellar populations in the RGB
The Javalambre Photometric Local Universe Survey (J-PLUS) provides wide
field-of-view images in 12 narrow, intermediate and broad-band filters
optimized for stellar photometry. Here we have applied J-PLUS data for the
first time for the study of Galactic GCs using science verification data
obtained for the very metal-poor GC M\,15. Our J-PLUS data provide
low-resolution spectral energy distributions covering the near-UV to the
near-IR, allowing us to search for MPs based on pseudo-spectral fitting
diagnostics. J-PLUS CMDs are found to be particularly useful to search for
splits in the sequences formed by the upper red giant branch (RGB) and
asymptotic giant branch (AGB) stars. We interpret these split sequences as
evidence for the presence of MPs. This demonstrates that the J-PLUS survey will
have sufficient spatial coverage and spectral resolution to perform a large
statistical study of GCs through multi-band photometry in the coming years.Comment: 11 pages, 11 figures. Accepted for publication @ A&
A comprehensive view of the interstellar medium in a quasar host galaxy at z~6.4
Characterizing the physical conditions (density, temperature, ionization
state, metallicity, etc) of the interstellar medium is critical to our
understanding of the formation and evolution of galaxies. Here we present a
multi-line study of the interstellar medium in the host galaxy of a quasar at
z~6.4, i.e., when the universe was 840 Myr old. This galaxy is one of the most
active and massive objects emerging from the dark ages, and therefore
represents a benchmark for models of the early formation of massive galaxies.
We used the Atacama Large Millimeter Array to target an ensemble of tracers of
ionized, neutral, and molecular gas, namely the fine-structure lines: [OIII]
88m, [NII] 122m, [CII] 158m, and [CI] 370m and the
rotational transitions of CO(7-6), CO(15-14), CO(16-15), and CO(19-18); OH
163.1m and 163.4m; and HO 3(0,3)-2(1,2), 3(3,1)-4(0,4),
3(3,1)-3(2,2), 4(0,4)-3(1,3), 4(3,2)-4(2,3). All the targeted fine-structure
lines are detected, as are half of the targeted molecular transitions. By
combining the associated line luminosities, the constraints on the dust
temperature from the underlying continuum emission, and predictions from
photoionization models of the interstellar medium, we find that the ionized
phase accounts for about one third of the total gaseous mass budget, and is
responsible for half of the total [CII] emission. It is characterized by high
density (n~180 cm), typical of HII regions. The spectral energy
distribution of the photoionizing radiation is comparable to that emitted by
B-type stars. Star formation also appears to drive the excitation of the
molecular medium. We find marginal evidence for outflow-related shocks in the
dense molecular phase, but not in other gas phases. This study showcases the
power of multi-line investigations in unveiling the properties of the
star-forming medium in galaxies at cosmic dawn.Comment: 16 pages, 14 figures. Accepted for publication in A&
MCT8 expression in human fetal cerebral cortex is reduced in severe intrauterine growth restriction
The importance of the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), to human neurodevelopment is highlighted by findings of severe global neurological impairment in subjects with MCT8 (SLC16A2) mutations. Intrauterine growth restriction (IUGR), usually due to uteroplacental failure, is associated with milder neurodevelopmental deficits, which have been partly attributed to dysregulated TH action in utero secondary to reduced circulating fetal TH concentrations and decreased cerebral thyroid hormone receptor expression. We postulate that altered MCT8 expression is implicated in this pathophysiology; therefore, in this study, we sought to quantify changes in cortical MCT8 expression with IUGR. First, MCT8 immunohistochemistry was performed on occipital and parietal cerebral cortex sections obtained from appropriately grown for gestational age (AGA) human fetuses between 19 weeks of gestation and term. Secondly, MCT8 immunostaining in the occipital cortex of stillborn IUGR human fetuses at 24–28 weeks of gestation was objectively compared with that in the occipital cortex of gestationally matched AGA fetuses. Fetuses demonstrated widespread MCT8 expression in neurons within the cortical plate and subplate, in the ventricular and subventricular zones, in the epithelium of the choroid plexus and ependyma, and in microvessel wall. When complicated by IUGR, fetuses showed a significant fivefold reduction in the percentage area of cortical plate immunostained for MCT8 compared with AGA fetuses (P<0.05), but there was no significant difference in the proportion of subplate microvessels immunostained. Cortical MCT8 expression was negatively correlated with the severity of IUGR indicated by the brain:liver weight ratios (r(2)=0.28; P<0.05) at post-mortem. Our results support the hypothesis that a reduction in MCT8 expression in the IUGR fetal brain could further compromise TH-dependent brain development
A far-IR view of the starburst driven superwind in NGC 2146
NGC 2146, a nearby luminous infrared galaxy (LIRG), presents evidence for
outflows along the disk minor axis in all gas phases (ionized, neutral atomic
and molecular). We present an analysis of the multi-phase starburst driven
superwind in the central 5 kpc as traced in spatially resolved spectral line
observations, using far-IR Herschel PACS spectroscopy, to probe the effects on
the atomic and ionized gas, and optical integral field spectroscopy to examine
the ionized gas through diagnostic line ratios. We observe an increased ~250
km/s velocity dispersion in the [OI] 63 micron, [OIII] 88 micron, [NII] 122
micron and [CII] 158 micron fine-structure lines that is spatially coincident
with high excitation gas above and below the disk. We model this with a slow
~200 km/s shock and trace the superwind to the edge of our field of view 2.5
kpc above the disk. We present new SOFIA 37 micron observations to explore the
warm dust distribution, and detect no clear dust entrainment in the outflow.
The stellar kinematics appear decoupled from the regular disk rotation seen in
all gas phases, consistent with a recent merger event disrupting the system. We
consider the role of the superwind in the evolution of NGC 2146 and speculate
on the evolutionary future of the system. Our observations of NGC 2146 in the
far-IR allow an unobscured view of the wind, crucial for tracing the superwind
to the launching region at the disk center, and provide a local analog for
future ALMA observations of outflows in high redshift systems.Comment: 16 pages, 13 figures, accepted for publication in Ap
The Herschel Comprehensive (U)LIRG Emission Survey (HerCULES): CO Ladders, fine structure lines, and neutral gas cooling
(Ultra) Luminous Infrared Galaxies ((U)LIRGs) are objects characterized by
their extreme infrared (8-1000 m) luminosities (L and L). The Herschel Comprehensive ULIRG
Emission Survey (HerCULES; PI van der Werf) presents a representative
flux-limited sample of 29 (U)LIRGs that spans the full luminosity range of
these objects (10). With the \emph{Herschel
Space Observatory}, we observe [CII] 157 m, [OI] 63 m, and [OI] 145
m line emission with PACS, CO J=4-3 through J=13-12, [CI] 370 m, and
[CI] 609 m with SPIRE, and low-J CO transitions with ground-based
telescopes. The CO ladders of the sample are separated into three classes based
on their excitation level. In 13 of the galaxies, the [OI] 63 m emission
line is self absorbed. Comparing the CO excitation to the IRAS 60/100 m
ratio and to far infrared luminosity, we find that the CO excitation is more
correlated to the far infrared colors. We present cooling budgets for the
galaxies and find fine-structure line flux deficits in the [CII], [SiII], [OI],
and [CI] lines in the objects with the highest far IR fluxes, but do not
observe this for CO . In order to study the heating of the
molecular gas, we present a combination of three diagnostic quantities to help
determine the dominant heating source. Using the CO excitation, the CO J=1-0
linewidth, and the AGN contribution, we conclude that galaxies with large CO
linewidths always have high-excitation CO ladders, and often low AGN
contributions, suggesting that mechanical heating is important
The [C II] emission as a molecular gas mass tracer in galaxies at low and high redshift
We present ALMA Band 9 observations of the [C II]158um emission for a sample of 10 main-sequence galaxies at redshift z ~ 2, with typical stellar masses (log M*/Msun ~ 10.0 - 10.9) and star formation rates (~ 35 - 115 Msun/yr). Given the strong and well understood evolution of the interstellar medium from the present to z = 2, we investigate the behaviour of the [C II] emission and empirically identify its primary driver. We detect [C II] from six galaxies (four secure, two tentative) and estimate ensemble averages including non detections. The [C II]-to-infrared luminosity ratio (L[C II]/LIR) of our sample is similar to that of local main-sequence galaxies (~ 2 x 10^-3), and ~ 10 times higher than that of starbursts. The [C II] emission has an average spatial extent of 4 - 7 kpc, consistent with the optical size. Complementing our sample with literature data, we find that the [C II] luminosity correlates with galaxies' molecular gas mass, with a mean absolute deviation of 0.2 dex and without evident systematics: the [C II]-to-H2 conversion factor (alpha_[C II] ~ 30 Msun/Lsun) is largely independent of galaxies' depletion time, metallicity, and redshift. [C II] seems therefore a convenient tracer to estimate galaxies' molecular gas content regardless of their starburst or main-sequence nature, and extending to metal-poor galaxies at low and high redshifts. The dearth of [C II] emission reported for z > 6 - 7 galaxies might suggest either a high star formation efficiency or a small fraction of UV light from star formation reprocessed by dust
Efeito de variações térmicas sobre a germinação de quatro espécies arbóreas com ampla distribuição geográfica no Brasil.
bitstream/item/136914/1/comunicado-tecnico-196.pdfApresentado como resumo no: SIMPÓSIO DE RECURSOS GENÉTICOS PARA AMÉRICA LATINA E O CARIBE, 10., 2015, Bento Gonçalves. Anais... Bento Gonçalves: Aptor Software, 2015. p. 150. SP 20828o
Survival of probiotic strains in a refrigerated nonfermentd blended juice using a static in vitro digestion model.
Ref. 378/139. ICDF, 2 a 4 de abril 2019. Na publicação: Gomes, F.; Ribeiro, A.; Ribeiro, L.; Matta, V.; Santos, K.; Walter, E
- …