Distribution Of Point Sources Research Articles

Deconstructing a galaxy: colour distributions of point sources in Messier 83

What do we see when we look at a nearby, well-resolved galaxy? Thousands of individual sources are detected in multiband imaging observations of even a fraction of a nearby galaxy, and characterizing those sources is a complex process. This work analyses a ten-band photometric catalogue of nearly 70 000 point sources in a 7.3 square arcmin region of the nearby spiral galaxy Messier 83, made as part of the Early Release Science programme with the Hubble Space Telescope's Wide Field Camera 3. Colour distributions were measured for both broad-band and broad-and-narrow-band colours; colours made from broad-bands with large wavelength differences generally had broader distributions although B - V was an exception. Two- and three-dimensional colour spaces were generated using various combinations of four bands and clustered with the K-Means and Mean Shift algorithms. Neither algorithm was able to consistently segment the colour distributions: while some distinct features in colour space were apparent in visual examinations, these features were not compact or isolated enough to be recognized as clusters in colour space. K-Means clustering of the UBVI colour space was able to identify a group of objects more likely to be star clusters. Mean Shift was successful in identifying outlying groups at the edges of colour distributions. For identifying objects whose emission is dominated by spectral lines, there was no clear benefit from combining narrow-band photometry in multiple bands compared to a simple continuum subtraction. The clustering analysis results are used to inform recommendations for future surveys of nearby galaxies.

The underwater sound field from impact pile driving: Observations and modeling of key features in the time domain

Observations of the pressure time series made from a vertical line array at range of order 10 waveguide depths from the pile source are presented along with interpretive modeling. Modeling is based on conceptualizing underwater sound from impact pile driving as originating from a vertical distribution of harmonic point sources uniformly distributed along the wetted-length of the pile, each source phased prior to summation in the frequency domain. This leads to credible representations of pressure time series as function of range and depth that are linearly related to field measurements. In particular, precursor arrivals which arrive prior to any water borne arrival as result of having propagated through a higher-speed sediment, and deterministic manifestations of the Mach cone effect within the main pressure time series, are shown in comparison with modeling results. Both phenomena are influenced by the increasing sediment excursion of the pile, and the importance of the sound speed gradient and sediment ...

Conductive transport through a mixed-matrix membrane

Conductive transport through an infinite homogeneous medium across a layer of finite thickness, a planar array of infinite cylinders, or a planar array of three-dimensional particles with arbitrary conductivity is considered as a model of mixed-matrix membrane separation. The boundary distribution of the transported scalar field on the interior side of the layer, cylinders, or particles is proportional to that on the exterior side according to a linear sorption/desorption kinetics law, while the conductive flux is continuous across the interface. In the case of cylinders and particles, the solution of Laplace’s equation for the transported field is represented by an interfacial distribution of point sources expressed in terms of the periodic Green’s function of Laplace’s equation in two dimensions or the doubly periodic Green’s function of Laplace’s equation in three dimensions. Analytical solutions for small circular cylinders and small spherical particles are derived based on the integral representation, and numerical solution of integral equations arising from the interfacial conditions are computed by boundary-element methods. The results document the displacement of the linear profile of the transported field far from the interfacial layer or array with respect to that prevailing in the absence of membrane. Expressions for the effective diffusivity of the mixed-matrix membrane are derived.

Refining an inverse dispersion method to quantify gas sources on rolling terrain

This paper analyses a trace gas dispersion experiment with multiple point sources and line-averaging laser gas detectors on gently rolling terrain. The objective of the experiment was to establish how well emission rate can be inferred by “inverse dispersion” (ID), using a Lagrangian stochastic wind transport model (WindTrax) that (strictly) is appropriate only in horizontally-homogeneous winds. Measured mean wind speeds at fixed height above ground revealed spatial variation of order ±10% over the site. However the results of the inversion to estimate source strength Q from the concentration field suggest that the unwanted impact of the terrain is adequately compensated by representing detector light paths as curves, approximating their true height above ground. Under that treatment the mean and standard deviation of the ratio QIDM/Q of inferred to true source strength, over an ensemble of 96 fifteen minute intervals, were respectively 〈QIDM/Q〉=1.04 and σQ|Q=0.15, with little distinction between outcomes under unstable and stable stratification. We also used the measurements to study the influence (on the accuracy of retrieved source strength) of discretionary elements of inverse dispersion procedure: data quality criteria; optimal placement of detectors relative to the source(s); and the impact of alternative spatial representations of the source, supposing one had but partial information in that regard. Because the sources were always rather close to the downwind detector, the quality of the inversions was less sensitive to extremes of stratification than has been reported for other trials. Inversions that treated the actual point sources as an aggregate area source proved acceptable, provided this was placed at or near the height of the (true) point sources. An idealized distribution of elevated point sources can also be satisfactory, but bad inversions may result if placement of the token sources is biased in the cross-plot direction relative to the actual source(s).

Development of an optimized Compton suppression gamma-ray spectrometric system using Monte Carlo simulation

We have chosen to establish the Compton Suppression Spectrometer (CSS) for low activity environmental samples with a high purity germanium (HPGe) primary detector and a removable plug-in detector (NaI(Tl)) surrounded with a cylindrical annulus guard detector (NaI(Tl)). Monte Carlo simulation with PENELOPE (PENetration and Energy LOss of Positrons and Electrons) is used to determine the optimal geometry of the CSS. To verify a correlation between experiment and simulation, the energy distribution of 137Cs and 60Co point sources is measured and simulated for each condition. The CSS parameters are studied to determine optimal detector geometry and Compton Suppression Factor (CSF). The timing resolution of the CSS was found to be 44ns (FWHM), which is an outstanding result in the semiconductor-based gamma-ray spectrometry. All measured values of CSF agree within 5% with the values obtained from the simulation. The optimum geometry and CSF values are discussed.

Acoustic radiation from the submerged circular cylindrical shell treated with active constrained layer damping**Project supported by the National Natural Science Foundation of China (Grant Nos. 11162001, 11502056, and 51105083), the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2012GXNSFAA053207), the Doctor Foundation of Guangxi University of Science and Technology, China (Grant No. 12Z09), and the Development Project

Based on the transfer matrix method of exploring the circular cylindrical shell treated with active constrained layer damping (i.e., ACLD), combined with the analytical solution of the Helmholtz equation for a point source, a multi-point multipole virtual source simulation method is for the first time proposed for solving the acoustic radiation problem of a submerged ACLD shell. This approach, wherein some virtual point sources are assumed to be evenly distributed on the axial line of the cylindrical shell, and the sound pressure could be written in the form of the sum of the wave functions series with the undetermined coefficients, is demonstrated to be accurate to achieve the radiation acoustic pressure of the pulsating and oscillating spheres respectively. Meanwhile, this approach is proved to be accurate to obtain the radiation acoustic pressure for a stiffened cylindrical shell. Then, the chosen number of the virtual distributed point sources and truncated number of the wave functions series are discussed to achieve the approximate radiation acoustic pressure of an ACLD cylindrical shell. Applying this method, different radiation acoustic pressures of a submerged ACLD cylindrical shell with different boundary conditions, different thickness values of viscoelastic and piezoelectric layer, different feedback gains for the piezoelectric layer and coverage of ACLD are discussed in detail. Results show that a thicker thickness and larger velocity gain for the piezoelectric layer and larger coverage of the ACLD layer can obtain a better damping effect for the whole structure in general. Whereas, laying a thicker viscoelastic layer is not always a better treatment to achieve a better acoustic characteristic.

Phase-coherent mapping of gravitational-wave backgrounds using ground-based laser interferometers

We extend the formalisms developed in Gair et al. and Cornish and van Haasteren to create maps of gravitational-wave backgrounds using a network of ground-based laser interferometers. We show that in contrast to pulsar timing arrays, which are insensitive to half of the gravitational-wave sky (the curl modes), a network of ground-based interferometers is sensitive to both the gradient and curl components of the background. The spatial separation of a network of interferometers, or of a single interferometer at different times during its rotational and orbital motion around the Sun, allows for recovery of both components. We derive expressions for the response functions of a laser interferometer in the small-antenna limit, and use these expressions to calculate the overlap reduction function for a pair of interferometers. We also construct maximum-likelihood estimates of the + and x-polarization modes of the gravitational-wave sky in terms of the response matrix for a network of ground-based interferometers, evaluated at discrete times during Earth's rotational and orbital motion around the Sun. We demonstrate the feasibility of this approach for some simple simulated backgrounds (a single point source and spatially-extended distributions having only grad or curl components), calculating maximum-likelihood sky maps and uncertainty maps based on the (pseudo)inverse of the response matrix. The distinction between this approach and standard methods for mapping gravitational-wave power is also discussed.

Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources

Abstract. Methane (CH4) from ruminants contributes one-third of global agricultural greenhouse gas emissions. Eddy covariance (EC) technique has been extensively used at various flux sites to investigate carbon dioxide exchange of ecosystems. Since the development of fast CH4 analyzers, the instrumentation at many flux sites has been amended for these gases. However, the application of EC over pastures is challenging due to the spatially and temporally uneven distribution of CH4 point sources induced by the grazing animals. We applied EC measurements during one grazing season over a pasture with 20 dairy cows (mean milk yield: 22.7 kg d−1) managed in a rotational grazing system. Individual cow positions were recorded by GPS trackers to attribute fluxes to animal emissions using a footprint model. Methane fluxes with cows in the footprint were up to 2 orders of magnitude higher than ecosystem fluxes without cows. Mean cow emissions of 423 ± 24 g CH4 head−1 d−1 (best estimate from this study) correspond well to animal respiration chamber measurements reported in the literature. However, a systematic effect of the distance between source and EC tower on cow emissions was found, which is attributed to the analytical footprint model used. We show that the EC method allows one to determine CH4 emissions of cows on a pasture if the data evaluation is adjusted for this purpose and if some cow distribution information is available.

The AKARI far-infrared all-sky survey maps

Abstract We present a far-infrared all-sky atlas from a sensitive all-sky survey using the Japanese AKARI satellite. The survey covers > 99% of the sky in four photometric bands centred at 65 μm, 90 μm, 140 μm, and 160 μm, with spatial resolutions ranging from 1′ to 1${^{\prime\prime}_{.}}$5. These data provide crucial information on the investigation and characterisation of the properties of dusty material in the interstellar medium (ISM), since a significant portion of its energy is emitted between ∼ 50 and 200 μm. The large-scale distribution of interstellar clouds, their thermal dust temperatures, and their column densities can be investigated with the improved spatial resolution compared to earlier all-sky survey observations. In addition to the point source distribution, the large-scale distribution of ISM cirrus emission, and its filamentary structure, are well traced. We have made the first public release of the full-sky data to provide a legacy data set for use in the astronomical community.

Accounting for the effect of diffuse reflections and fittings within street canyons, on the sound propagation predicted by ray tracing codes

Diffusion on building facades and fittings within a street can significantly affect sound propagation in urban areas. These phenomena are however not reproduced by the widespread outdoor sound propagation models that are based on ray codes algorithms, because their modeling would induce increased computational costs. In this paper, a set of 32 175 simulations is achieved with a sound particle tracing code to quantify the errors made when neglecting acoustic diffusion within street canyons, according to the street geometry (width, height, distance between the point source and the receiver), the acoustical properties of the street (diffusion and absorption coefficient of the facades, absorption coefficient of the ground), and the acoustical properties of the fittings (mean free path and average absorption coefficient), in the case of a receiver height of 1.5m. The diffuse reflections can lead to reduction of 2dB to an increase of 4dB of sound pressure levels in the absence of fittings, and can lead to an increase of 10dB of sound pressure levels in the presence of fittings, for the most unfavorable configurations. The influence of the acoustical parameters and the influence of the street geometry on sound attenuation are closely linked to each other. Moreover, acoustic diffusion results in an overall sound level increase if one considers a linear point source distribution. Finally, regressions are proposed that estimate the impact of diffusive reflections and street fittings on sound propagation as a function of the input parameters. These regressions can now be advantageously used to refine sound levels estimations within street canyons, when using classical outdoor sound propagation models, in the range of the parameters tested.

Microvascular Hemodynamics in the Chick Chorioallantoic Membrane (CAM)

Theoretical modeling techniques were employed to investigate the hemodynamic coupling between arterioles, capillaries and venules in the developing microcirculation of the chorioallantoic membrane (CAM) of the chick embryo, based on structural and hemodynamic experimental observations. The microvasculature of the CAM is characterized by interdigitating arteriolar and venular trees, both of which are linked to a mesh-like capillary plexus. A day-14 CAM network with an area of about 1 cm2 was imaged and digitally reconstructed, providing information about vessel length, diameter, and 3D location of over 7000 vessel segments. Since the capillary plexus structure was not resolved by imaging, it was modeled as a porous medium. The supply of blood from the arterioles to the capillaries and drainage into the venules were represented by distributions of point sources and sinks of flow. Predicted flow velocities were compared with blood velocity measurements in arterioles and venules with diameters 16 to 100 µm, obtained in the CAM via video microscopy. If it was assumed that blood flows into the capillary plexus only at the ends of terminal arterioles, the predicted velocities increased with decreasing diameter in vessels <50 µm in diameter, contrary to the observations. Distributing sources or sinks at 50 µm intervals along arterioles and venules led to velocities consistent with the data. The results imply that vascular connections to the capillary plexus must be present along the length of the arterioles and venules, not only at the ends of terminal arterioles and venules. This research was supported by NIH HL034555 and HL070657.

Monte Carlo simulation of shielded chair whole body counting system with Masonite cut sheet phantom

The shielded chair wholebody counting system used at IGCAR is calibrated experimentally using Masonite cut sheet phantom loaded with single radionuclide of known activity. Multiple point sources of a particular radionuclide are distributed at mid-thickness in each segment of the phantom during calibration. Though the detector can be used for the measurement of gamma photons upto 3000 keV, the experimental calibration is done only upto 1500 keV according to the requirement of measurement of fission and activation products, which emits gamma energies predominantly in the regions below 1500 keV. The expertize in numerical Monte Carlo simulation was utilized to obtain the efficiency values above 1500 keV. This paper focuses on the validation of the shielded chair counting system model using the Masonite cut sheet phantom measurements and applying the validated model to extend the energy range of the calibration upto 3 MeV. A good agreement of the theoretically simulated and experimental 137 Cs spectrum with respect to the spectral shape, counts in all the energy regions and the photopeak efficiency validated the modeling of the counting system. A mathematical function to fit the counting efficiencies with photon energies was developed and a set of fitting parameters were established so that the efficiency value of any energy upto 3 MeV can be obtained without performing experimental efficiency calibration. The efficiency values obtained from the fit were compared with experimental ones and found to be in agreement, i.e., within 8% for the 250–1500 keV energy range. The Compton scattering factors (CSFs) at different low energies due to high energy photons were also simulated. The theoretical and experimental CSFs were compared and found to be matching within ±20%. Simulations with uniform source distribution inside the Masonite phantom has shown that the current source distribution followed at IGCAR gives efficiency values within ±5% compared to that of uniform distribution. • MCNP modeling of the shielded chair wholebody counting system with the Masonite phantom and its validation using experiments. • Theoretical simulation of efficiency values and CSFs for different energies. • Established an equation to estimate the efficiency values in the energy range 250–3000 keV. • Theoretically established that the present multiple point source distribution at mid-thickness closely represents the uniform source distribution.

The role of CO2 emissions from large point sources in emissions totals, responsibility, and policy

A large fraction of anthropogenic CO2 emissions comes from large point sources such as power plants, petroleum refineries, and large industrial facilities. The existence and locations of these facilities depend on a variety of factors that include the distribution of natural resources and the economy of scale of operating large facilities. These large facilities provide goods and/or services well beyond the political jurisdiction in which they reside and their emissions to the global atmosphere are not a simple reflection of the consumption of goods and services within the geographic region in which they reside. And yet many accounting schemes do not distinguish between emissions for local consumption and emissions for export. Looking at the geographic distribution of large point sources of CO2 emissions in theU.S. suggests that per capita emissions from a geographic area are not necessarily a good indication of the mitigation responsibility of the residents. The design of effective and fair mitigation strategies needs to consider that emissions embodied in the products of large facilities, such as electric power and refined petroleum products, are often transferred across accounting boundaries; e.g. the CO2 emissions occur in one jurisdiction even though the electricity is used in another. We close with a short discussion of how two sub-national emissions trading schemes in the U.S. have confronted the issue of embodied emissions crossing their jurisdictional boundaries.

FMNEAR: Determination of Focal Mechanism and First Estimate of Rupture Directivity Using Near-Source Records and a Linear Distribution of Point Sources

Abstract The FMNEAR method is based on both the waveform inversion of near‐source seismic records and on a linear finite‐source model. The primary source parameters that are determined are the moment magnitude ( M w ), the double‐couple focal mechanism (strike, dip, and rake), and the distribution of seismic moment along strike, which provides a first‐order estimate of rupture length and directivity. Source depth is also explored. An advantage of the approach is the use of the finite‐source model directly within the search of the focal mechanism. This strategy allows the inclusion of strong‐motion records at short distances for moderate to very large earthquakes ( M w >5.5). However, for moderate to small earthquakes ( M w M w 4.5 to 9.0. Test cases incorporate continental events recorded by a large number of well‐distributed stations and less favorable cases. In its present form, the FMNEAR approach is very well adapted to continental earthquakes surrounded by seismic stations, but it can also give informative results in more difficult configurations. The FMNEAR method is now ready for fully automated determinations and is already implemented in near real time. Online Material: Details on inversion parameters, flow charts of the FMNEAR method, figures of waveform modeling and sensitivity for selected events, and table of velocity models.

Correction algorithms for signal reduction in insensitive areas of a small gamma camera

The radiation sensitive part of the wide-field, small gamma camera Sentinella™ 108 consists of a monolithic, 102 × 102 mm2 wide CsI(Na) crystal coupled to four position-sensitive photomultipliers. These are read out via a resistor mesh reducing the 256 PMT channels to four digitized values which allow for an image reconstruction, based on polynomials, with high spatial resolution. The sensor areas between neighboring PMTs suffer from reduced detection efficiency for scintillation light. The corresponding lack of signal amplitude translates to a poor uniformity and additional image compression in the border regions of the images after the first step of reconstruction. These effects cannot be completely eliminated by a global calibration procedure alone.We have developed and evaluated two classes of algorithms to compensate for this reduction of signal amplitude. Corrections are applied for each detected event separately, maintaining the real-time capability of the gamma camera. Algorithm 1 is based on a four-parameter, geometric calculation of the four output signals. This model aims to attack the underlying lack of detection efficiency without further assumptions on the true event distribution, preserving the global polynomial image decompression. Algorithm 2, to the contrary, starts from measured reference distributions of point sources which are used to model local deformations and energy loss without further information on the underlying detector geometry. Here too, a good image quality has been obtained after application of the deduced corrections.These algorithms are applied in the first step of event reconstruction. Within an energy interval of ±0.2Ep around the photopeak position of 99mTc, Ep = 140.5 keV, and comparing several cameras, global uniformities around 5–8% have been obtained with both models. Measured energy resolutions are about 9–14%.

Impacts assessment of air emissions from point sources in Saskatchewan, Canada — A spatial analysis approach

Air pollutants emanating from industrial point sources account for a large proportion of air pollution issues. Besides, emissions from these sources are technically controllable while other sources, for example, soil erosion, forest fires, and road travel, are subject to some unpredictable natural or economic factors. Therefore, most research efforts regarding air pollution control have concentrated on industrial point sources. In this study, an effective approach with the aid of spatial analysis is presented to evaluate the potential impacts of air pollutant emissions from point sources in Saskatchewan, Canada. Trend analyses are first carried out to demonstrate the temporal changes in the total number of and the spatial distribution of point sources from 1994 to 2008. Then, the IDW method is used to generate interpolation surfaces for main air pollutants emitted by industrial sources with the purpose of disclosing their emission patterns. Following that, 10 representative industrial facilities are screened out to estimate the impacts of PM2.5 on the surrounding residents, aiming to demonstrate the effectiveness of the proposed approach. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 304–313, 2015

A stochastic approach to Galactic proton propagation: Influence of the spiral arm structure

A newly developed numerical code solving Fokker–Planck type transport equations in currently four dimensions (space plus momentum or energy) and time by means of stochastic differential equations (SDEs) is applied to the Galactic propagation of Cosmic Ray protons, where the paths of pseudo particles originating in spiral arms and in the interarm region are traced back to a distribution of point sources. The transport equation in this first, simplified approach includes scalar spatial diffusion and catastrophic energy losses. In a first step we validate the code by obtaining results being consistent with previous ones obtained with finite-difference methods, revealing lower spectra with less variations in the interarm region compared to the inarm region. While Effenberger et al. (2012) used this approach to study the effects of a fully anisotropic diffusion tensor, we concentrate here on a diffusion coefficient taking into account the spiral arm structure. Such a variable diffusion coefficient is of importance e.g. for the long-scale time-variation of the Cosmic Ray flux at Earth related to spiral arm crossings. For our choice of parameters, we find that a diffusion coefficient reflecting the spiral arm structure leads to a clearly enhanced flux ratio between the inarm and interarm regions. The strength of this effect depends, however, on the parameters chosen.

Assessing Water Quality of Three Gorges Reservoir, China, Over a Five-Year Period From 2006 to 2011

Understanding temporal variability in water quality in the Three Gorges Reservoir (TGR) is crucial for evaluating environmental effects of damming and protecting China’s largest freshwater resource. This study examined water quality changes in the main channel of the Yangtze River after dam completion as well as its relationship with water level fluctuation (WLF), controlled by annual impoundment operations and conditioned by flooding. Finally, the mass balance budget and integrative water quality indexing (WQI) methods were applied to elucidate the status of overall water quality since dam completion. Results showed that TGR outlet water (Yichang) exhibited higher pH and CODMn values and lower concentrations of dissolved oxygen (DO) and ammonia nitrogen (NH3-N) than inlet water (Zhutuo). Temporal variations in water quality parameters displayed similar trends for the outlet and inlet. Water quality parameters all showed negative correlations to water level, revealing the different effects of damming on water quality. It was estimated that reservoir impoundment led to a DO depletion of 1495.5 (±1482.0) × 103 tons/yr and a CODMn increase of 564.0 (±405.0) × 103 tons/yr, likely deriving from various internal pollutant loads from the WLF zone and tributary watersheds. According to WQI, TGR water quality remained at healthy levels. However, WQI linear regression showed that water quality at the outlet significantly decreased over time, indicating that the construction of the Three Gorges Dam generally caused water quality deterioration. Further investigation is required to determine the spatial distribution of point and non-point pollution sources and to identify major factors that influence TGR water quality.

The initial conditions of the Universe from constrained simulations

Abstract I present a new approach to recover the primordial density fluctuations and the cosmic web structure underlying a galaxy distribution. The method is based on sampling Gaussian fields which are compatible with a galaxy distribution and a structure formation model. This is achieved by splitting the inversion problem into two Gibbs-sampling steps: the first being a Gaussianization step transforming a distribution of point sources at Lagrangian positions – which are not a priori given– into a linear alias-free Gaussian field. This step is based on Hamiltonian sampling with a Gaussian–Poisson model. The second step consists on a likelihood comparison in which the set of matter tracers at the initial conditions is constrained on the galaxy distribution and the assumed structure formation model. For computational reasons second-order Lagrangian perturbation theory is used. However, the presented approach is flexible to adopt any structure formation model. A semi-analytic halo-model-based galaxy mock catalogue is taken to demonstrate that the recovered initial conditions are closely unbiased with respect to the actual ones from the corresponding N-body simulation down to scales of a ∼5 Mpc h−1. The cross-correlation between them shows a substantial gain of information, being at k ∼ 0.3 h Mpc−1 more than doubled. In addition the initial conditions are extremely well Gaussian distributed and the power spectra follow the shape of the linear power spectrum being very close to the actual one from the simulation down to scales of k ∼ 1 h Mpc−1.

LOW-FREQUENCY IMAGING OF FIELDS AT HIGH GALACTIC LATITUDE WITH THE MURCHISON WIDEFIELD ARRAY 32 ELEMENT PROTOTYPE

The Murchison Widefield Array (MWA) is a new low-frequency, wide field-of-view radio interferometer under development at the Murchison Radio-astronomy Observatory (MRO) in Western Australia. We have used a 32-element MWA prototype interferometer (MWA-32T) to observe two 50-degree diameter fields in the southern sky in the 110 MHz to 200 MHz band in order to evaluate the performance of the MWA-32T, to develop techniques for epoch of reionization experiments, and to make measurements of astronomical foregrounds. We developed a calibration and imaging pipeline for the MWA-32T, and used it to produce ~15' angular resolution maps of the two fields. We perform a blind source extraction using these confusion-limited images, and detect 655 sources at high significance with an additional 871 lower significance source candidates. We compare these sources with existing low-frequency radio surveys in order to assess the MWA-32T system performance, wide field analysis algorithms, and catalog quality. Our source catalog is found to agree well with existing low-frequency surveys in these regions of the sky and with statistical distributions of point sources derived from Northern Hemisphere surveys; it represents one of the deepest surveys to date of this sky field in the 110 MHz to 200 MHz band.