34 research outputs found
Molecular Gas Properties of the Giant Molecular Cloud Complexes in the Arms and Inter-arms of the Spiral Galaxy NGC 6946
Combining observations of multiple CO lines with radiative transfer modeling
is a very powerful tool to investigate the physical properties of the molecular
gas in galaxies. Using new observations as well as literature data, we provide
the most complete CO ladders ever generated for eight star-forming regions in
the spiral arms and inter-arms of the spiral galaxy NGC 6946, with observations
of the CO(1-0), CO(2-1), CO(3-2), CO(4-3), CO(6-5), 13CO(1-0) and 13CO(2-1)
transitions. For each region, we use the large velocity gradient assumption to
derive beam-averaged molecular gas physical properties, namely the gas kinetic
temperature (T_K), H2 number volume density n(H2) and CO number column density
N(CO). Two complementary approaches are used to compare the observations with
the model predictions: chi-square minimisation and likelihood. The physical
conditions derived vary greatly from one region to the next: T_K=10-250 K,
n(H2)=10^2.3-10^7.0 cm^-3 and N(CO)=10^15.0-10^19.3 cm^-2. The spectral line
energy distribution (SLED) of some of these extranuclear regions indicates a
star-formation activity that is more intense than that at the centre of our own
Milky Way. The molecular gas in regions with a large SLED turnover transition
(J_max>4) is hot but tenuous with a high CO column density, while that in
regions with a low SLED turnover transition (J_max<=4) is cold but dense with a
low CO column density. We finally discuss and find some correlations between
the physical properties of the molecular gas in each region and the presence of
young stellar population indicators (supernova remnants, HII regions, HI holes,
etc.)Comment: 23 pages, 11 figures, MNRAS, Accepte
ISM chemistry in metal rich environments: molecular tracers of metallicity
In this paper we use observations of molecular tracers in metal rich and
alpha-enhanced galaxies to study the effect of abundance changes on molecular
chemistry. We selected a sample of metal rich spiral and star bursting objects
from the literature, and present here new data for a sample of early-type
galaxies (ETGs). We conducted the first survey of CS and methanol emission in
ETGs, detecting 7 objects in CS, and 5 in methanol emission. We find evidence
to support the hypothesis that CS is a better tracer of dense star-forming gas
than HCN. We suggest that the methanol emission in these sources is driven by
dust mantle destruction due to ionisation from high mass star formation, but
cannot rule out shocks dominating in some sources. The derived source averaged
CS/methanol column densities and rotation temperatures are similar to those
found in normal spiral and starburst galaxies, suggesting dense clouds are
little affected by the differences between galaxy types. Finally we used the
total column density ratios for our galaxy samples to show for the first time
that some molecular tracers do seem to show systematic variations that appear
to correlate with metallicity, and that these variations roughly match those
predicted by chemical models. Using this fact, the chemical models of Bayet et
al. (2012b), and assumptions about the optical depth we are able to roughly
predict the metallicity of our spiral and ETG sample, with a scatter of ~0.3
dex. We provide the community with linear approximations to the relationship
between the HCN and CS column density ratio and metallicity. Further study will
clearly be required to determine if this, or any, molecular tracer can be used
to robustly determine gas-phase metallically, but that a relationship exists at
all suggests that in the future it may be possible to calibrate a metallicity
indicator for the molecular interstellar medium (abridged).Comment: 14 pages, 9 figures. MNRAS, accepte
Smooth muscle tumor of uncertain malignant potential (STUMP): a case-based analysis
Objectives: The present study aimed to analyze of uterine smooth muscle tumors of uncertain malignant potential (STUMP) and the outcomes of patients with STUMP.
Material and methods: In this retrospective study, the data of patients diagnosed with STUMP in a single tertiary center between January 2005–January 2020 were reviewed. We assessed the demographic variables, treatment outcomes, time until recurrence, disease-free and overall survival of the patients.
Results: Twenty-five patients diagnosed with STUMP were included in the study. The mean age of the patients was 43.2 ± 10.3 years. Thirteen of the 25 patients (52%) were treated by myomectomy, others received diagnoses following hysterectomy. The median follow-up time was 45.2 months. Recurrence was observed in three cases (12%), two of which were followed up without hysterectomy, and the third patient died by peritonitis carcinomatosa 60 months after diagnosis although she received cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) treatment.
Conclusions: This study evaluates the data of patients with STUMP. Our results reveal a STUMP recurrence of 12%, like those previously reported in the literature. Despite the possibility of malignant recurrence, fertility-preserving treatment with close follow-up should be tried, because of the relatively early age at diagnosis
Probing molecular gas and its physical conditions in disc galaxies
New observations of multiple molecular gas tracers in nearby early- and late-types
galaxies are presented and are used to study the physical conditions of the gas
within different morphological structures. The CO Tully-Fisher relation is also
constructed for a sample of star-forming galaxies at z = 0:05 - 0:3, probing their
mass and size evolution.
First, using single-dish observations of multiple locations within the nearby spiral
galaxy NGC 6946, extensive CO ladders are generated. The molecular line ratios
reveal a large variety of physical conditions across the molecular gas complexes,
depending primarily on the presence of current or recent star formation, itself
compared with that in the centre of the galaxy and other galaxies.
Second, interferometric observations of CO and high density molecular tracers in
the nearby edge-on early-type galaxies NGC 4710 and NGC 5866 are presented.
The gas kinematics reveals that the galaxies are barred, with most of the gas
contained within a nuclear disc and a distinct inner ring. Using the molecular
line ratios to probe the physical conditions of the gas, the nuclear discs appear
to have a more diffuse and hotter molecular medium than the inner rings, with
more embedded dense clumps. This suggests that the conditions in the nuclear
discs are similar to those in photo-dissociation regions, with intense UV radiation
from young stars and few cosmic rays. Indeed, the observed molecular line ratios
are also intermediate between those of spiral galaxies and starbursts, with even
milder star formation in the inner rings.
Third, homogeneously measuring the line widths in the CO spectra of star-forming
disc galaxies at z = 0:05 - 0:3, their Ks-band CO Tully-Fisher relation is constructed.
A comparison to local star-forming galaxy TFRs from the literature
provides mild evidence that our sample galaxies are ≈ 0:89 mag brighter than
local ones at a given rotational velocity, a result entirely consistent with our stellar
mass TFR, suggesting that our sample galaxies are more massive than local
ones by ≈ 0:35 dex. While they deserve further scrutiny, we suspect that these
results are due to our sample galaxies being more heavily star-forming (and thus
brighter at a given mass) than the comparison sample galaxies.</p
Probing molecular gas and its physical conditions in disc galaxies
New observations of multiple molecular gas tracers in nearby early- and late-types galaxies are presented and are used to study the physical conditions of the gas within different morphological structures. The CO Tully-Fisher relation is also constructed for a sample of star-forming galaxies at z = 0:05 - 0:3, probing their mass and size evolution. First, using single-dish observations of multiple locations within the nearby spiral galaxy NGC 6946, extensive CO ladders are generated. The molecular line ratios reveal a large variety of physical conditions across the molecular gas complexes, depending primarily on the presence of current or recent star formation, itself compared with that in the centre of the galaxy and other galaxies. Second, interferometric observations of CO and high density molecular tracers in the nearby edge-on early-type galaxies NGC 4710 and NGC 5866 are presented. The gas kinematics reveals that the galaxies are barred, with most of the gas contained within a nuclear disc and a distinct inner ring. Using the molecular line ratios to probe the physical conditions of the gas, the nuclear discs appear to have a more diffuse and hotter molecular medium than the inner rings, with more embedded dense clumps. This suggests that the conditions in the nuclear discs are similar to those in photo-dissociation regions, with intense UV radiation from young stars and few cosmic rays. Indeed, the observed molecular line ratios are also intermediate between those of spiral galaxies and starbursts, with even milder star formation in the inner rings. Third, homogeneously measuring the line widths in the CO spectra of star-forming disc galaxies at z = 0:05 - 0:3, their Ks-band CO Tully-Fisher relation is constructed. A comparison to local star-forming galaxy TFRs from the literature provides mild evidence that our sample galaxies are ≈ 0:89 mag brighter than local ones at a given rotational velocity, a result entirely consistent with our stellar mass TFR, suggesting that our sample galaxies are more massive than local ones by ≈ 0:35 dex. While they deserve further scrutiny, we suspect that these results are due to our sample galaxies being more heavily star-forming (and thus brighter at a given mass) than the comparison sample galaxies.</p
Bezier Surface Modeling for Neutrosophic Data Problems
The main goal of this paper is to construct Bézier surface modeling for neutrosophic data problems. We show how to build the surface model over a data sample from agriculture science after the theoretical structure of the modeling is introduced. As a sampler application for agriculture systems, we give a visualization of Bézier surface model of an estimation of a given yield of bean seeds grown in a field over a period
Bezier Curve Modeling for Neutrosophic Data Problem
Neutrosophic set concept is defined with membership, non-membership and indeterminacy degrees. This concept is the solution and representation of the problems with various fields. In this paper, a geometric model is introduced for Neutrosophic data problem for the first time. This model is based on neutrosophic sets and neutrosophic relations. Neutrosophic control points are defined according to these points, resulting in neutrosophic Bezier curves
Bezier Surface Modeling for Neutrosophic Data Problems
The main goal of this paper is to construct Bezier surface modeling for neutrosophic data problems. We show how to build the surface model over a data sample from agriculture science after the theoretical structure of the modeling is introduced. As a sampler application for agriculture systems, we give a visualization of Bezier surface model of an estimation of a given yield of bean seeds grown in a field over a period
Bezier Curve Modeling for Neutrosophic Data Problem
Neutrosophic set concept is defined with membership, non-membership and indeterminacy degrees. This concept is the solution and representation of the problems with various fields. In this paper, a geometric model is introduced for Neutrosophic data problem for the first time. This model is based on neutrosophic sets and neutrosophic relations. Neutrosophic control points are defined according to these points, resulting in neutrosophic B`ezier curves