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At least 91 records · Page 5

COLLIMATION AND SCATTERING OF THE ACTIVE GALACTIC NUCLEUS EMISSION IN THE SOMBRERO GALAXY

We present an analysis of a data cube of the central region of M104, the Sombrero galaxy, obtained with the GMOS-IFU of the Gemini-South telescope, and report the discovery of collimation and scattering of the active galactic nucleus (AGN) emission in the circumnuclear region of this galaxy. Analysis with PCA Tomography and spectral synthesis revealed the existence of collimation and scattering of the AGN featureless continuum and also of a broad component of the H{alpha} emission line. The collimation and scattering of this broad H{alpha} component was also revealed by fitting the [N II] {lambda}{lambda}6548, 6583 and H{alpha} emission lines as a sum of Gaussian functions. The spectral synthesis, together with a V-I image obtained with the Hubble Space Telescope, showed the existence of circumnuclear dust, which may cause the light scattering. We also identify a dusty feature that may be interpreted as a torus/disk structure. The existence of two opposite regions with featureless continuum (P.A. = -18 Degree-Sign {+-} 13 Degree-Sign and P.A. = 162 Degree-Sign {+-} 13 Degree-Sign ) along a direction perpendicular to the torus/disk (P.A. = 72 Degree-Sign {+-} 14 Degree-Sign ) suggests that this structure is approximately edge-on and collimates the AGN emission. The edge-on torus/disk also hides the broad-line region. The proposed scenario is compatible with the unified model and explains why only a weak broad component of the H{alpha} emission line is visible and also why many previous studies detected no broad H{alpha}. The technique used here proved to be an efficient method not only for detecting scattered light, but also for testing the unified model in low-luminosity AGNs.

79 ASTRONOMY AND ASTROPHYSICS↗

Neural Learning Based Blind Source Separation for Detection of Material Defects in Pulsed Thermography Images

In this paper, we introduce a neural learning-based approach to blind source separation for detection of material flaws in pulsed thermography (PT) images. This approach can be used to detect internal defects (pores) in metallic Additively Manufactured (AM) materials. Such defects occur in high-strength alloys produced with direct laser sintering AM method for nuclear energy applications. Pulsed thermal imaging system utilizes a high intensity flash lamp to rapidly heat surface of sample, a high sensitivity infrared camera to capture data of surface temperature variations. The data cube obtained with PT (stack of surface temperature images at different times) can be analyzed with image processing algorithms to detect material defects. Compared with conventional nondestructive evaluation (NDE) methods, such as digital radiography and ultrasonic testing, the PT pulsed infrared thermal detection technique has advantages of one-sided non-contact measurements, fast processing of large sample areas captured in one image. Detection of small material defects requires finding features in thermal images, which have signal contrast levels approaching sensitivity limit of IR camera. In this study, an optimized Neural Learning based Blind Source Separation (NLBSS) algorithm, including Principal Component Analysis (PCA), and Independent Component Analysis (ICA) is demonstrated to automatically extract principal temporal and spatial features of thermography frames to enhance flaw detection. By using the NLBSS algorithm, material internal defects can be automatically detected. Furthermore, this processing approach compensates for experimental thermal imaging artifacts, such as noise and uneven heating. By merging artificial intelligence with the photothermic, the NDE system detects internal calibrated defects of various sizes and depths in AM nuclear-grade metallic alloys.

Zhang, Xin↗

Gulf of Mexico Miocene CO2 Site Characterization Mega Transect

The project Gulf of Mexico Miocene CO2 Site Characterization Mega Transect is one of 9 site characterization projects that were implemented as part of ARRA (American Recovery and Reinvestment Act). Data from this project was used to improve resolution of data in NATCARB in the area of study. Data related to this study has already been incorporated in NATCARB Atlas. The University of Texas at Austin study focused on (1) collecting high-resolution, 3-D (HR3D) seismic datasets of the shallow geologic section to evaluate the capacity of potential reservoirs and the sealing capacity of the confining system, and (2) producing a regional CO2 atlas of Miocene age units of the upper Texas coast submerged lands (southeast Texas). The goal of the study was to evaluate the capability of the Miocene age geologic section of Texas submerged lands to permanently store large volumes of anthropogenic CO2. The geographic locations of three HR3D, “P-Cable” seismic surveys collected in the near-shore waters of southeast Texas offers a vertical and horizontal view (data “cube”) example from the second survey. The dataset's high quality allowed for defining recognizable geologic morphologies (shapes) and possible fluid content, which are important for determining an area’s prospects for geologic storage. The regional CO2 atlas of Miocene age units highlights several topics, including: (1) a regional analyses of petroleum systems as analogs for CO2 storage; (2) petrography, petrology, and extent of confining systems of the Miocene section; (3) static capacity estimate; and (4) examples of characterization methodologies of prospect areas. The HR3D datasets and regional analyses within the CO2 atlas of the offshore Texas Miocene provide a sound basis for a future generation of specific CO2 prospects in the study area.

.las↗

Performance of Pulsed Thermal Tomography Imaging with Machine Learning-Based Classification of Defects in Additively Manufactured Structures

Additive manufacturing (AM) is an emerging method for cost-efficient fabrication of complex topology nuclear reactor parts from high-strength corrosion resistance alloys, such as stainless steel and Inconel. AM of metallic structures for nuclear energy applications is currently based on laser powder bed fusion (LPBF) process. Some of the challenges with using LPBF method for nuclear manufacturing include the possibility of introducing pores into metallic structures. Integrity of AM structures needs to be evaluated nondestructively because material flaws could lead to premature failures in high temperature nuclear reactor environment. Currently, there exist limited capabilities to evaluate actual AM structures non-destructively. Pulsed Thermal Tomography Imaging (PTT) provides a capability for non-destructive evaluation (NDE) of subsurface defects in arbitrary size structures. The PTT method is based on recording material surface temperature transients with infrared (IR) camera following thermal pulse delivered on material surface with flash light. The PTT method has advantages for NDE of actual AM structures because the method involves one-sided non-contact measurements and fast processing of large sample areas captured in one image. Following initial qualification of an AM component for deployment in a nuclear reactor, a PTT system can also be used for in-service nondestructive evaluation (NDE) applications. In this report, we describe recent progress in enhancing PTT capabilities in detecting and visualizing microscopic defects in metallic specimens. The thermal tomography (TT) algorithm obtains depth reconstructions of spatial effusivity from the data cube of sequentially recorded surface temperatures. However, interpretation of TT images is non-trivial because of blurring of images with increasing depth. To address this challenge, we have developed a deep learning convolutional neural network (CNN) to classify size and orientation subsurface defects in simulated TT images. CNN is trained on a database of TT images created for a set of simulated metallic structures with elliptical subsurface voids. Test of CNN performance demonstrate the ability to classify radii and angular orientation of subsurface defects in TT images. In addition, we have shown that CNN trained on elliptical defects is capable of classifying irregular-shaped defects obtained from scanning electron microscopy (SEM) of stainless steel sections printed with LPBF.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Pulsed Thermal Tomography Nondestructive Examination of Additively Manufactured Reactor Materials and Components. Third Annual Progress Report

Additive manufacturing (AM) of high-strength corrosion resistance alloys for nuclear energy applications, such as stainless steel and Inconel, is currently based on laser powder bed fusion (LPBF) process. Some of the challenges with using LPBF method for nuclear manufacturing include the possibility of introducing pores into metallic structures. Probability of crack initiation at the pore depends on size, shape, and orientation of the defect. Pulsed Infrared Thermography Imaging (PIT) provides a capability for non-destructive evaluation (NDE) of sub-surface defects in arbitrary size structures. The PIT method is based on recording material surface temperature transients with infrared (IR) camera following thermal pulse delivered on material surface with flash light. The PIT method has advantages for NDE of actual AM structures because the method involves one-sided non-contact measurements and fast processing of large sample areas captured in one image. Following initial qualification of an AM component for deployment in a nuclear reactor, a PIT system can also be used for in-service nondestructive evaluation (NDE) applications. In this report, we describe recent progress in enhancing PIT capabilities in detecting microscopic subsurface defects in metals, and classifying shapes and orientation of pores in thermal images. For detection of microscopic defects in PIT imaging data, we have developed Spatial Temporal Denoised Thermal Source Separation (STDTSS) unsupervised machine learning (ML) image processing algorithm. We show that flat bottom hole (FBH) defects as small as 200µm in SS316 and IN718 specimens, can be detected with STDTSS algorithm. To the best of our knowledge, these are the smallest detected defects which are reported in literature. For classification of defects shapes, we have previously developed thermal tomography (TT) algorithm to obtain depth reconstructions of material defects from data cube of sequentially recorded surface temperatures. However, interpretation of TT images is non-trivial because of blurring with increasing depth. To address this challenge, we have developed a deep learning convolutional neural network (CNN) to classify size and orientation subsurface defects in simulated TT images.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Heating and Acceleration of Solar Wind by Parametric Decay Instability Mediated Turbulence

One of the main goals of this project to understand the origin of density fluctuations in the solar winds, as revealed by the NASA’s Flagship satellite Parker Solar Probe (PSP) measurements, which motivates us to simulate and analyze magnetohydrodynamic (MHD) turbulence in the compressible regime. To achieve this goal, we have developed a set of sophisticated turbulence driving methods to study how MHD turbulence will develop under different time-correlated fluctuations at large-scales. Another key advance is that we have developed a new 3+1 (three spatial plus time domain) 4D FFT analysis of simulation data-cubes so that we can perform the spatio-temporal spectrum and mode decomposition studies on MHD turbulence.

79 ASTRONOMY AND ASTROPHYSICS↗

THE OFF-CENTERED SEYFERT-LIKE COMPACT EMISSION IN THE NUCLEAR REGION OF NGC 3621

We analyze an optical data cube of the nuclear region of NGC 3621, taken with the integral field unit of the Gemini Multi-object Spectrograph. We found that the previously detected central line emission in this galaxy actually comes from a blob, located at a projected distance of 2.″14 ± 0.″08 (70.1 ± 2.6 pc) from the stellar nucleus. Only diffuse emission was detected in the rest of the field of view, with a deficit of emission at the position of the stellar nucleus. Diagnostic diagram analysis reveals that the off-centered emitting blob has a Seyfert 2 spectrum. We propose that the line-emitting blob may be a “fossil” emission-line region or a light “echo” from an active galactic nucleus (AGN), which was significantly brighter in the past. Our estimates indicate that the bolometric luminosity of the AGN must have decreased by a factor of ∼13–500 during the past ∼230 yr. A second scenario to explain the morphology of the line-emitting areas in the nuclear region of NGC 3621 involves no decrease of the AGN bolometric luminosity and establishes that the AGN is highly obscured toward the observer but not toward the line-emitting blob. The third scenario proposed here assumes that the off-centered line-emitting blob is a recoiling supermassive black hole, after the coalescence of two black holes. Finally, an additional hypothesis is that the central X-ray source is not an AGN, but an X-ray binary. This idea is consistent with all the scenarios we proposed.

79 ASTRONOMY AND ASTROPHYSICS↗

HIGHLY EXCITED H{sub 2} IN HERBIG–HARO 7: FORMATION PUMPING IN SHOCKED MOLECULAR GAS?

We have obtained K -band spectra at R ∼ 5000 and an angular resolution of 0.″3 of a section of the Herbig–Haro 7 (HH7) bow shock, using the Near-Infrared Integral Field Spectrograph at Gemini North. Present in the portion of the data cube corresponding to the brightest part of the bow shock are emission lines of H{sub 2} with upper state energies ranging from ∼6000 K to the dissociation energy of H{sub 2}, ∼50,000 K. Because of low signal-to-noise ratios, the highest excitation lines cannot be easily seen elsewhere in the observed region. However, excitation temperatures, measured throughout much of the observed region using lines from levels as high as 25,000 K, are a strong function of upper level energy, indicating that the very highest levels are populated throughout. The level populations in the brightest region are well fit by a two-temperature model, with 98.5% of the emitting gas at T = 1800 K and 1.5% at T = 5200 K. The bulk of the H{sub 2} line emission in HH7, from the 1800 K gas, has previously been well-modeled by a continuous shock, but the 5200 K cozmponent is inconsistent with standalone standard continuous shock models. We discuss various possible origins for the hot component and suggest that this component is H{sub 2} newly reformed on dust grains and then ejected from them, presumably following dissociation of some of the H{sub 2} by the shock.

79 ASTRONOMY AND ASTROPHYSICS↗

TOWARD PRECISION BLACK HOLE MASSES WITH ALMA: NGC 1332 AS A CASE STUDY IN MOLECULAR DISK DYNAMICS

We present first results from a program of Atacama Large Millimeter/submillimeter Array (ALMA) CO(2–1) observations of circumnuclear gas disks in early-type galaxies. The program was designed with the goal of detecting gas within the gravitational sphere of influence of the central black holes (BHs). In NGC 1332, the 0.″3-resolution ALMA data reveal CO emission from the highly inclined (i≈83{sup ∘}) circumnuclear disk, spatially coincident with the dust disk seen in Hubble Space Telescope images. The disk exhibits a central upturn in maximum line-of-sight velocity, reaching ±500 km s{sup −1} relative to the systemic velocity, consistent with the expected signature of rapid rotation around a supermassive BH. Rotational broadening and beam smearing produce complex and asymmetric line profiles near the disk center. We constructed dynamical models for the rotating disk and fitted the modeled CO line profiles directly to the ALMA data cube. Degeneracy between rotation and turbulent velocity dispersion in the inner disk precludes the derivation of strong constraints on the BH mass, but model fits allowing for a plausible range in the magnitude of the turbulent dispersion imply a central mass in the range of ∼(4–8) × 10{sup 8} M{sub ⊙}. We argue that gas-kinematic observations resolving the BH’s projected radius of influence along the disk’s minor axis will have the capability to yield BH mass measurements that are largely insensitive to systematic uncertainties in turbulence or in the stellar mass profile. For highly inclined disks, this is a much more stringent requirement than the usual sphere-of-influence criterion.

79 ASTRONOMY AND ASTROPHYSICS↗

Studying magnetohydrodynamic turbulence with synchrotron polarization dispersion

We test a new technique for studying magnetohydrodynamic turbulence suggested by Lazarian and Pogosyan, using synthetic observations of synchrotron polarization. This paper focuses on a one-point statistics, which is termed polarization frequency analysis, that is characterized by the variance of polarized emission as a function of the square of the wavelength along a single line of sight. We adopt the ratio η of the standard deviation of the line-of-sight turbulent magnetic field to the line-of-sight mean magnetic field to depict the level of turbulence. When this ratio is large (η≫1), which characterizes a region dominated by turbulent field, or small (η≲0.2), which characterizes a region dominated by the mean field, we obtain the polarization variance 〈P{sup 2}〉∝λ{sup −2} or 〈P{sup 2}〉∝λ{sup −2−2m}, respectively. At small η, i.e., in the region dominated by the mean field, we successfully recover the turbulent spectral index from the polarization variance. We find that our simulations agree well with the theoretical prediction of Lazarian and Pogosyan. With existing and upcoming data cubes from the Low-Frequency Array for Radio Astronomy (LOFAR) and the Square Kilometer Array (SKA), this new technique can be applied to study the magnetic turbulence in the Milky Way and other galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗

THE THEORETICAL ASTROPHYSICAL OBSERVATORY: CLOUD-BASED MOCK GALAXY CATALOGS

We introduce the Theoretical Astrophysical Observatory (TAO), an online virtual laboratory that houses mock observations of galaxy survey data. Such mocks have become an integral part of the modern analysis pipeline. However, building them requires expert knowledge of galaxy modeling and simulation techniques, significant investment in software development, and access to high performance computing. These requirements make it difficult for a small research team or individual to quickly build a mock catalog suited to their needs. To address this TAO offers access to multiple cosmological simulations and semi-analytic galaxy formation models from an intuitive and clean web interface. Results can be funnelled through science modules and sent to a dedicated supercomputer for further processing and manipulation. These modules include the ability to (1) construct custom observer light cones from the simulation data cubes; (2) generate the stellar emission from star formation histories, apply dust extinction, and compute absolute and/or apparent magnitudes; and (3) produce mock images of the sky. All of TAO’s features can be accessed without any programming requirements. The modular nature of TAO opens it up for further expansion in the future.

79 ASTRONOMY AND ASTROPHYSICS↗

THE ARIZONA RADIO OBSERVATORY CO MAPPING SURVEY OF GALACTIC MOLECULAR CLOUDS. V. THE SH2-235 CLOUD IN CO J = 2 − 1, {sup 13}CO J = 2 − 1, AND CO J = 3 − 2

We present the results of a program to map the Sh2-235 molecular cloud complex in the CO and {sup 13}CO J = 2 − 1 transitions using the Heinrich Hertz Submillimeter Telescope. The map resolution is 38″ (FWHM), with an rms noise of 0.12 K brightness temperature, for a velocity resolution of 0.34 km s{sup −1}. With the same telescope, we also mapped the CO J = 3 − 2 line at a frequency of 345 GHz, using a 64 beam focal plane array of heterodyne mixers, achieving a typical rms noise of 0.5 K brightness temperature with a velocity resolution of 0.23 km s{sup −1}. The three spectral line data cubes are available for download. Much of the cloud appears to be slightly sub-thermally excited in the J = 3 level, except for in the vicinity of the warmest and highest column density areas, which are currently forming stars. Using the CO and {sup 13}CO J = 2 − 1 lines, we employ an LTE model to derive the gas column density over the entire mapped region. Examining a 125 pc{sup 2} region centered on the most active star formation in the vicinity of Sh2-235, we find that the young stellar object surface density scales as approximately the 1.6-power of the gas column density. The area distribution function of the gas is a steeply declining exponential function of gas column density. Comparison of the morphology of ionized and molecular gas suggests that the cloud is being substantially disrupted by expansion of the H ii regions, which may be triggering current star formation.

79 ASTRONOMY AND ASTROPHYSICS↗

A Method to Extract Spatially Resolved Polycyclic Aromatic Hydrocarbon Emission from Spitzer Spectra: Application to M51

The mid-infrared spectrum contains rich diagnostics to probe the physical properties of galaxies, among which the pervasive emission features from polycyclic aromatic hydrocarbons (PAHs) offer promising means of estimating the star formation rate (SFR) relatively immune from dust extinction. This paper investigates the effectiveness of PAH emission as a SFR indicator on subkiloparsec scales by studying the Spitzer/IRS mapping-mode observations of the nearby grand-design spiral galaxy M51. We present a new approach of analyzing the spatial elements of the spectral data cube that simultaneously maximizes spatial resolution and spatial coverage, while yielding reliable measurements of the total, integrated 5–20 μm PAH emission. We devise a strategy of extracting robust PAH emission using spectra with only partial spectral coverage, complementing missing spectral regions with properly combined mid-infrared photometry. We find that in M51 the PAH emission correlates tightly with the extinction-corrected far-ultraviolet, near-ultraviolet, and Hα emission, from scales of ∼0.4 kpc close to the nucleus to 6 kpc out in the disk of the galaxy, indicating that PAH serves as an excellent tracer of SFR over a wide range of galactic environments. But regional differences exist. Close to the active nucleus of M51 the 6.2 μm feature is weaker, and the overall level of PAH emission is suppressed. The spiral arms and the central star-forming region of the galaxy emit stronger 7.7 and 8.6 μm PAH features than the inter-arm regions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Wide-field {sup 12}CO (J=2--1) and {sup 13}CO (J=2--1) Observations toward the Aquila Rift and Serpens Molecular Cloud Complexes. I. Molecular Clouds and Their Physical Properties

We present the results of wide-field {sup 12}CO (J=2--1) and {sup 13}CO (J=2--1) observations toward the Aquila Rift and Serpens molecular cloud complexes (25{sup ∘}<l<33{sup ∘} and 1{sup ∘}<b<6{sup ∘}) at an angular resolution of 3.′4 (≈0.25 pc) and at a velocity resolution of 0.079 km s{sup −1} with velocity coverage of −5 km s{sup −1}<V{sub LSR}<35 km s{sup −1}. We found that the {sup 13}CO emission better traces the structures seen in the extinction map, and derived the X{sub {sup 1}{sup 3}CO}-factor of this region. Applying SCIMES to the {sup 13}CO data cube, we identified 61 clouds and derived their mass, radii, and line widths. The line width–radius relation of the identified clouds basically follows those of nearby molecular clouds. The majority of the identified clouds are close to virial equilibrium, although the dispersion is large. By inspecting the {sup 12}CO channel maps by eye, we found several arcs that are spatially extended to 0.°2–3° in length. In the longitude–velocity diagrams of {sup 12}CO, we also found two spatially extended components that appear to converge toward Serpens South and the W40 region. The existence of two components with different velocities and arcs suggests that large-scale expanding bubbles and/or flows play a role in the formation and evolution of the Serpens South and W40 cloud.

79 ASTRONOMY AND ASTROPHYSICS↗

Casting the Coronal Magnetic Field Reconstruction Tools in 3D Using the MHD Bifrost Model

Quantifying the coronal magnetic field remains a central problem in solar physics. Nowadays, the coronal magnetic field is often modeled using nonlinear force-free field (NLFFF) reconstructions, whose accuracy has not yet been comprehensively assessed. Here we perform a detailed casting of the NLFFF reconstruction tools, such as π -disambiguation, photospheric field preprocessing, and volume reconstruction methods, using a 3D snapshot of the publicly available full-fledged radiative MHD model. Specifically, from the MHD model, we know the magnetic field vector in the entire 3D domain, which enables us to perform a “voxel-by-voxel” comparison of the restored and the true magnetic fields in the 3D model volume. Our tests show that the available π -disambiguation methods often fail in the quiet-Sun areas dominated by small-scale magnetic elements, while they work well in the active region (AR) photosphere and (even better) chromosphere. The preprocessing of the photospheric magnetic field, although it does produce a more force-free boundary condition, also results in some effective “elevation” of the magnetic field components. This “elevation” height is different for the longitudinal and transverse components, which results in a systematic error in absolute heights in the reconstructed magnetic data cube. The extrapolations performed starting from the actual AR photospheric magnetogram are free from this systematic error, while other metrics are comparable with those for extrapolations from the preprocessed magnetograms. This finding favors the use of extrapolations from the original photospheric magnetogram without preprocessing. Our tests further suggest that extrapolations from a force-free chromospheric boundary produce measurably better results than those from a photospheric boundary.

79 ASTRONOMY AND ASTROPHYSICS↗

HALOGAS Observations of NGC 4559: Anomalous and Extraplanar H i and its Relation to Star Formation

We use new deep 21 cm H i observations of the moderately inclined galaxy NGC 4559 in the HALOGAS survey to investigate the properties of extraplanar gas. We use TiRiFiC to construct simulated data cubes to match the H i observations. We find that a thick-disk component of scale height ∼2 kpc, characterized by a negative vertical gradient in its rotation velocity (lag) of ∼13 ± 5 km s{sup −1} kpc{sup −1} is an adequate fit to extraplanar gas features. The tilted ring models also present evidence for a decrease in the magnitude of the lag outside R {sub 25}, and a radial inflow of ∼10 km s{sup −1}. We extracted lagging extraplanar gas through Gaussian velocity profile fitting. From both the 3D models and extraction analyses we conclude that ∼10%–20% of the total H i mass is extraplanar. Most of the extraplanar gas is spatially coincident with regions of star formation in spiral arms, as traced by H α and GALEX FUV images, so it is likely due to star formation processes driving a galactic fountain. We also find the signature of a filament of a kinematically “forbidden” H i feature, containing ∼1.4 × 10{sup 6} M {sub ⊙} of H i, and discuss its potential relationship to a nearby H i hole. We discover a previously undetected dwarf galaxy in H i located ∼0.°4 (∼58 kpc) from the center of NGC 4559, containing ∼4 × 10{sup 5} M {sub ⊙}. This dwarf has counterpart sources in SDSS with spectra typical of H ii regions, and we conclude that it is two merging blue compact dwarf galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗

Measurement of the black hole mass in NGC 1332 from ALMA observations at 0.044 arcsecond resolution

We present Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 3 observations of CO(2–1) emission from the circumnuclear disk in the E/S0 galaxy NGC 1332 at 0.″044 resolution. The disk exhibits regular rotational kinematics and central high-velocity emission (±500 km s{sup −1}) consistent with the presence of a compact central mass. We construct models for a thin, dynamically cold disk in the gravitational potential of the host galaxy and black hole and fit the beam-smeared model line profiles directly to the ALMA data cube. Model fits successfully reproduce the disk kinematics out to r = 200 pc. Fitting models just to spatial pixels within projected r = 50 pc of the nucleus (two times larger than the black hole’s gravitational radius of influence), we find M{sub BH}=(6.64{sub −0.63}{sup +0.65})×10{sup 8} M{sub ⊙}. This observation demonstrates ALMA’s powerful capability to determine the masses of supermassive black holes by resolving gas kinematics on small angular scales in galaxy nuclei.

79 ASTRONOMY AND ASTROPHYSICS↗

LLNL Wind Cube V2 Lidar / Raw Data

This dataset contains vertical profiling lidar datafrom AWAKEN site A1. This is the WindCube v2 lidar. The Windcube v2 replaced the ZX300 at this location at the end of March 2023.

17 WIND ENERGY↗