Готові списки джерел за темами / Mass photometry

Добірка наукової літератури з теми "Mass photometry"

Автор: Grafiati

Опубліковано: 7 липня 2024

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Статті в журналах з теми "Mass photometry":

Prokhorov, M. E., A. I. Zakharov, V. G. Moshkalev, N. L. Krusanova, and M. S. Tuchin. "Mass Computations of the Brightness of Stars in an Arbitrary Spectral Band." Астрономический журнал 100, no. 6 (June 1, 2023): 500–511. http://dx.doi.org/10.31857/s0004629923050092.

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The problem of calculating the brightness of an array of stars in an arbitrary photometric band, which is not the standard band of astronomical photometry, is considered from their multicolor photometry in some other photometric system. A similar problem is to transfer photometric measurements of stars from one multicolor photometric system to another. This task includes methods for calculating and comparing magnitudes, as well as merging photometric catalogs. The questions of choice of various zero-points of photometry and reduction of measurements for the atmosphere are considered. The issues of reducing the error of the proposed methods are discussed. The article is partly based on a report presented at the conference “Modern Stellar Astronomy-2022”, held at the Caucasian Mountain Observatory of the Sternberg State Astronomical Institute, Moscow State University, in November 8–10, 2022.

Sarrouh, Ghassan T. E., Adam Muzzin, Kartheik G. Iyer, Lamiya Mowla, Sunna Withers, Nicholas S. Martis, Roberto Abraham, et al. "Exposing Line Emission: The Systematic Differences of Measuring Galaxy Stellar Masses with JWST NIRCam Medium versus Wide Band Photometry." Astrophysical Journal Letters 967, no. 1 (May 1, 2024): L17. http://dx.doi.org/10.3847/2041-8213/ad43e8.

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Abstract Photometrically derived stellar masses are known to suffer from systematic uncertainties, particularly due to nebular emission contributions to the spectral energy distribution (SED). Using James Webb Space Telescope NIRCam imaging from the CAnadian NIRISS Unbiased Cluster Survey, we introduce a comparison study of photometrically derived redshifts and stellar masses based on two photometric catalogs of the same field spanning ∼0.4–4.5 μm: one consisting solely of wide band photometry, and another employing a combination of wide and medium band photometry. We find that ∼70% of likely line emitters have consistent photometric redshifts between both catalogs, with a median stellar mass difference between the two catalogs of <0.2 dex across all redshift bins. There are, however, a subset of galaxies (5% at z ∼ 2 up to 15% at z ∼ 6) where wide bands underestimate emission line strengths and infer older stellar populations, leading to median stellar mass differences of ∼0.7 dex. Examination of the SEDs for galaxies with inconsistent photometric redshifts shows this is caused by the inability of the wide bands to distinguish continuum emission from emission lines. Computing a stellar mass density with our sample, we find that it is potentially underestimated using wide band photometry by ∼10%–20% at z < 4, and potentially overestimated by as much as a factor of 2–3 at z > 5. These systematic differences caused by the poor spectral resolution of wide bands have implications for both ongoing and future planned observing programs that determine stellar mass and other physical properties of high-redshift galaxies solely via wide band photometry.

ČAVLOVIĆ, ANKA OZANA, and IVAN BEŠLIĆ. "APPLICATION OF PHOTOMETRY IN DETERMINING THE DUST MASS CONCENTRATION OF HARDWOODS." WOOD RESEARCH 66(4) 2021 66, no. 4 (September 9, 2021): 678–88. http://dx.doi.org/10.37763/wr.1336-4561/66.4.678688.

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Given the carcinogenicity of hardwood dust, the aim of this study was to determine the effectiveness of the photometric method for different types of woodworking machines and its application in determining the mass concentration of inhalable dust for raw and dry hardwoods. In addition to the optical part of the device, the input part of the measuring device contains the Institute of Occupational Medicine (IOM) inhalable dust filter holder. This correlation of gravimetric and photometric methods in determining the dust mass concentration showed that photometry underestimates the mass concentration measured gravimetrically. The results of this study recommend the application of a correction factor 2 for a timber band saw and a correction factor 3 for circular saws in determining the mass concentration of hardwood dust by the photometric method. It was showed that photometry can be used if the correction factor of the optical device has been previously tested for specific wood processing place.

Cernic, Vitor. "Stellar Population Photometric Synthesis with AI of S-PLUS galaxies." Proceedings of the International Astronomical Union 16, S362 (June 2020): 148–49. http://dx.doi.org/10.1017/s1743921322001430.

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AbstractWe trained a Neural Network that can obtain selected STARLIGHT parameters directly from S-PLUS photometry. The training set consisted of over 55 thousand galaxies with their stellar population parameters obtained from a STARLIGHT application by Cid Fernandes et al. (2005). These galaxies were crossmatched with the S-PLUS iDR 3 database, thus, recovering the photometry for the 12 band filters for 55803 objects. We also considered the spectroscopic redshift for each object which was obtained from the SDSS. Finally, we trained a fully connected Neural Network with the 12-band photometry + redshift as features, and targeted some of the STARLIGHT parameters, such as stellar mass and mean stellar age. The model performed very well for some parameters, for example, the stellar mass, with an error of 0.23 dex. In the future, we aim to apply the model to all S-PLUS galaxies, obtaining never-before-seen photometric synthesis for most objects in the catalogue.

Jerzykiewicz, M. "Two Aspects of Using Hipparcos Data for Studying Multiperiodic Stellar Pulsations." International Astronomical Union Colloquium 176 (2000): 46–49. http://dx.doi.org/10.1017/s0252921100057043.

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AbstractTwo aspects of using Hipparcos data for studying multiperiodic stellar pulsations involve (1) deriving frequencies of multiperiodic pulsators from Hipparcos Epoch Photometry, and (2) using Hipparcos parallaxes together with other data, such as the frequencies, frequency ratios and multicolor photometry, to identify pulsation modes. Details are examined by looking at the δ Scuti star DK Virginis. From Hipparcos Epoch Photometry, two frequencies are derived. These frequencies are then verified by showing that they also fit all available ground-based observations of the star. In addition, Hipparcos parallax and a photometric effective temperature are used to compare the position of DK Vir in the HR diagram with evolutionary tracks. The star turns out to be at the end of core-hydrogen-burning stage of its evolution or slightly beyond, with a mass of 2.2 M⊙, or somewhat smaller. The observed frequencies indicate that the two detected modes are p3 and p2, while the relatively large photometric amplitudes imply ℓ ≲ 2.

Schilbach, E., H. Meusinger, and J. Souchay. "Luminosity and Mass Functions for the Pleiades from the Schmidt Survey." Symposium - International Astronomical Union 164 (1995): 379. http://dx.doi.org/10.1017/s0074180900108976.

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From MAMA measurements of Tautenburg and OCA Schmidt plates we obtained proper motions and photographic UBVR photometry for ca. 45 000 stars up to B = 19 mag within a 17 square degree region in the Pleiades. An accuracy of 0.6 mag and 2 mas/year was estimated for magnitudes and proper motions, respectively. A sample of 554 cluster members was separated by use of both astrometric and photometric information on stars.

Schmehl, T., J. Gebhart, H. Schutte, A. Scharmann, and W. Seeger. "On-line laser-photometric monitoring of aerosol deposition in ventilated rabbit lungs." Journal of Applied Physiology 80, no. 1 (January 1, 1996): 351–56. http://dx.doi.org/10.1152/jappl.1996.80.1.351.

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A photometric technique was developed for on-line measurement of aerosol deposition in isolated, ventilated, and perfused rabbit lungs. A jet nebulizer was used for aerosolization of saline (hygroscopic particles) and di(2-ethylhexyl) sebacate (nonhygroscopic particles). Aerosol concentration (laser photometer, constructed for measurements in rabbit lungs) and flow rate (commercial pneumotachograph) were continuously monitored at the inlet of the tracheal cannula. Computer-assisted data processing allowed the breath-by-breath calculation of inhaled and exhaled aerosol mass, thus providing the deposition fraction. With the use of hygroscopic particles, however, this approach was hampered by the humidity-induced particle growth in the airways, leading to an overestimation of the aerosol concentration in exhaled air. This effect was corrected by an algorithm using a “particle growth factor” derived breath by breath from the photometer signal. To test the reliability of this approach, saline particles carrying technetium-99m label were aerosolized into rabbit lungs with the use of various ventilator settings, and the aerosol deposition was assessed in parallel by photometry and by radioactivity detection over the lung and over a trap in the exhaled-air circuit. Superimposable curves of cumulative aerosol deposition, with changes in kinetics dependent on the ventilator mode, were obtained. For a given ventilator setting, absolute values of the deposition fraction were 0.32 +/- 0.04 (radiotracer quantification) and 0.36 +/- 0.04 (photometry; means +/- SD; n = 4). We conclude that the presented laser-photometric technique allows reliable on-line monitoring of the deposition of both nonhygroscopic and hygroscopic aerosol particles in ventilated lungs.

Wu, Di, and Grzegorz Piszczek. "Standard protocol for mass photometry experiments." European Biophysics Journal 50, no. 3-4 (March 2, 2021): 403–9. http://dx.doi.org/10.1007/s00249-021-01513-9.

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Lombardo, Linda, Patrick François, Piercarlo Bonifacio, Elisabetta Caffau, Aroa del Mar Matas Pinto, Corinne Charbonnel, Georges Meynet, Lorenzo Monaco, Gabriele Cescutti, and Alessio Mucciarelli. "Young giants of intermediate mass." Astronomy & Astrophysics 656 (December 2021): A155. http://dx.doi.org/10.1051/0004-6361/202141408.

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Context. In the search of a sample of metal-poor bright giants using Strömgren photometry, we serendipitously found a sample of 26 young (ages younger than 1 Gyr) metal-rich giants, some of which have high rotational velocities. Aims. We determined the chemical composition and rotational velocities of these stars in order to compare them with predictions from stellar evolution models. These stars where of spectral type A to B when on the main sequence, and we therefore wished to compare their abundance pattern to that of main-sequence A and B stars. Methods. Stellar masses were derived by comparison of the position of the stars in the colour-magnitude diagram with theoretical evolutionary tracks. These masses, together with Gaia photometry and parallaxes, were used to derive the stellar parameters. We used spectrum synthesis and model atmospheres to determine chemical abundances for 16 elements (C, N, O, Mg, Al, Ca, Fe, Sr, Y, Ba, La, Ce, Pr, Nd, Sm, and Eu) and rotational velocities. Results. The age-metallicity degeneracy can affect photometric metallicity calibrations. We identify 15 stars as likely binary stars. All stars are in prograde motion around the Galactic centre and belong to the thin-disc population. All but one of the sample stars present low [C/Fe] and high [N/Fe] ratios together with constant [(C+N+O)/Fe], suggesting that they have undergone CNO processing and first dredge-up. The observed rotational velocities are in line with theoretical predictions of the evolution of rotating stars.

Innis, John, and Denis Coates. "NEW CMOS PHOTOMETRY AND ARCHIVAL PHOTOGRAPHIC OBSERVATIONS OF THE W UMA STAR V752 CEN: EXTENDING THE O-C RECORD OF PERIOD CHANGES." Open European Journal on Variable stars, no. 224 (2022): 1–18. http://dx.doi.org/10.5817/oejv2022-0224.

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We present new CMOS Bayer g-band photometry of the southern W UMa star V752 Cen, presenting two new times of primary minimum, and use archival photographic photometry from the Bamberg Sky Survey (mid 1960s) and the Harvard plate collection (∼1890 to 1990) to extend the O-C diagram back in time to ∼1900. Earlier authors have reported a constant period from the earliest published photometry in 1970 to about the year 2000, when a sudden change occurred to an increasing period. The archival photographic record presented here indicates the period was effectively constant back to 1900. Our 2020 data are also consistent with reported period increase. The V752 Cen system is known from earlier work to be a W UMa binary orbiting a lower mass spectroscopic binary. Our preliminary calculations, based on the reported centre-of-mass velocity change of the W UMa binary, suggest the wide orbit may have a period near 245 d, and could give rise to a light-travel time-effect of order 0.02 d. This does not however appear to be consistent with the SuperWASP photometric O-C results. Hence we suggest that considerable uncertainty exists concerning the properties of the wide orbit.

Більше джерел

Дисертації з теми "Mass photometry":

Steele, Iain A. "Photometry and spectroscopy of low mass stars and brown dwarfs." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/35798.

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This thesis describes an investigation of the faintest known proper motion members of the Pleiades star cluster. The primary aim of the work is an attempt to determine whether the lowest mass members of the cluster are brown dwarfs. A brief introduction outlines the fundamental properties of brown dwarfs and discusses the relation of research in this area to other branches of astronomy. The second chapter describes the basic principles of astronomical photometry and spectroscopy, the instruments used and the methods of data reduction. Chapter three gives a review of the current theory and observations of brown dwarfs. The results are presented in chapters four, five and six. RIJHK photometry for a sample of 62 objects is presented. The 1,1 - K diagram is shown to be a good discriminant of binary status for low mass cluster objects and using this diagram two single brown dwarf candidates and seven potential brown dwarf containing binaries are identified. FOS optical spectroscopy of 31 objects is used in an investigation of temperature indicators for cool stars. In addition gravity sensitive features indicate that the surface gravity of the Pleiades objects is lower than equivalent main sequence objects. Also discussed are the chromospheric and coronal activity of cluster members, and evidence is presented showing a turnover in both at ~ 0.3M⊕, where the objects become fully convective. CGS4 1-2.5 micron spectra are used in a futher investigation of methods of determining effective temperature and in searching for evidence of low mass companions. One object shows evidence for a low mass companion of ~ 0.035M⊕. Chapter seven discusses the evidence from these results that the faintest members observed are brown dwarfs and evidence from other workers that they are not. This chapter also gives suggestions for future work. Appendices compile the theoretical models and data used in the project.

Scandariato, Gaetano. "The Initial Mass Function of the Orion Nebula Cluster from Near-Infrared Photometry." Doctoral thesis, Università di Catania, 2012. http://hdl.handle.net/10761/1027.

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The main goal of this thesis is the complete characterization of the IMF of the Orion Nebula Cluster (ONC) down to the Brown Dwarfs (BDs) regime, using ground-based Near-Infrared (NIR) photometric observations. The data taken in the framework of the Hubble Space Telescope (HST) Treasury Program on the ONC have been obtained with the wide-field imager Infrared Side Port Imager (ISPI) at the Blanco 4m telescope of CTIO, and cover an area of about 0.25 square degrees roughly centered on Theta1OriC. We observed the region in the JHKS bands with exposure times of 330 s. As a result of our survey, we provide 2MASS-calibrated astrometry and photometry for ~7000 sources in the ONC region. Analyzing our photometric sample, we derive the contamination-completeness corrected (J,J-H) CMDs of the ONC, canceling out the contribution from the contaminant population. We also develop a statistical algorithm, which combines the CMD of the ONC with our reference isochrone and, taking into account the presence of extinction and NIR excess, derives the intrinsic Luminosity Function (LF) of the cluster. We finally combine the LF with our empirical NIR isochrone to derive a statistical estimate of the IMF at different distances from the cluster center. We find that the mass distribution of the cluster is peaked at ~0.16 M and falls off crossing the hydrogen burning limit, continuously decreasing in the BDs domain down to ~0.03 M . We also find that the substellar-to-stellar objects ratio in the ONC decreases with increasing distance from the cluster center, suggesting that BDs are preferentially formed in the deep gravitational potential well where the most massive stars of the Trapezium cluster are also found.

Vika, Marina. "Supermassive black holes : the local supermassive black hole mass function." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/2553.

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Over recent years there has been an increase of the number of secure supermassive black hole (SMBH) detections. These SMBH measurements have lead astronomers to establish well defined empirical relationships between the SMBH mass and some of the properties of the host galaxy. The number of galaxies with SMBH mass measurements is currently limited to about 100. One approach of expanding the study of the SMBH is to use the empirical relations for estimating M[subscript(bh)] for larger samples of galaxies. The investigation of the SMBH population (or SMBH mass function) for large sample of galaxies in the nearby universe has helped to constrain the SMBH and the galaxy evolution. Previous estimates of the SMBH mass function at low redshift were produced mainly by combining the measurements of the galaxy luminosity or velocity function with one of the SMBH scaling relations. In the first part of the thesis I will present an independent construction of the nearby supermassive black hole mass function by applying the optical M[subscript(bh)]–L relation onto the Millennium Galaxy Catalogue (MGC). Additionally, in the second part I will provide photometric analysis of all UKIDSS galaxies for which SMBH masses have been measured. I will derive composite profiles of brightness, ellipticity and position angles of each galaxy. I will show that the Sérsic function fits the brightness profile of the majority of the elliptical galaxies and the bulge of disk galaxies and I will provide alternative multi-component fits when necessary. Then these photometric parameters will be used for constructing the M[subscript(bh)]–L relation in the near-IR and to investigate the M[subscript(bh)]–n relation. In the third part I will construct the near-IR SMBH mass function for the Galaxy and Mass Assembly (GAMA) survey. For this purpose I will apply the newly derived M[subscript(bh)]–L relation onto an elliptical subsample of K-band images. The advantage of this SMBH mass function is that during the M[subscript(bh)]–L construction I used the same quality images and techniques used on the GAMA survey. Apart from the M[subscript(bh)]–L relation, the M[subscript(bh)]–sigma relation was used as an alternative approach for a subsample of galaxies for which the velocity dispersions were available. Furthermore, I employed both local SMBH mass functions (MGC & GAMA) for estimating the SMBH mass density at redshift zero and accounted for the dependence of the total SMBH density on the look-back time by comparing with semi-analytic SMBH mass functions. Finally, from the SMBH mass density I estimated the baryon fraction that is locked into SMBHs.

Krawchuk, Curtis A. P. "The determination of metallicity and temperature of low-mass stars using broad-band photometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0035/MQ27361.pdf.

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King, Robert R. "Low-mass stars and brown dwarfs : optical/infrared photometry and spectroscopy of low-mass stars and brown dwarfs in the Field and Young Clusters." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/97095.

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In this thesis I will present optical and near-infrared photometric and spectroscopic observations of an evolved field brown dwarf binary pair and of populations of low-mass stars in high-mass young stellar clusters and will compare them to stellar and substellar theoretical model predictions. Epsilon Indi Ba and Bb are the closest known brown dwarfs to the Earth, and, as such, make possible a concerted observational campaign to obtain a complete characterisation of two intermediate-age T dwarfs. Although some recent observations suggest substellar atmospheric and evolutionary models may be inconsistent with observations, there have been few conclusive tests to date. I will present high angular resolution optical, near-infrared, and thermal-infrared imaging and medium-resolution (up to R~5000) spectroscopy of these two T dwarfs. Using these data I have derived luminosities of log L/Lsun = -4.699 +/- 0.017 and -5.232 +/- 0.020 for Epsilon Indi Ba, Bb, respectively, and I will show that the predictions of substellar evolutionary models using luminosity and mass constraints are inconsistent with the effective temperatures and surface gravities derived from fitting atmospheric models to observed spectra. Furthermore, I will show that, even where estimates of the effective temperature, surface gravity, and luminosity are available, estimates of the mass of cool brown dwarfs can be up to a factor of two lower than the measured dynamical mass. Considering the difficulty in assigning accurate ages to any system and the mass-luminosity-age degeneracy of brown dwarfs, I would caution against the over-analysis of predicted brown dwarf masses at this time. I have also used Chandra X-ray observations to identify near-complete and relatively unbiased samples of pre-main-sequence stars in the young stellar clusters NGC 2244 and Trumpler 14. Using optical photometric and spectroscopic observations, I will characterise the apparent age spreads seen in the cluster pre-main-sequences. Mass estimates will then be derived for their stellar populations and used to construct the initial mass function for each cluster. It is found that NGC 2244 appears to have a Salpeter-like IMF for stars in the mass range 0.5--2.0 Msun if a likely age of 2 Myr is adopted, while Tr 14 may have a top-heavy IMF at a similar age. However, I will show that because the observed slopes of the cluster pre-main-sequences are not well-matched by the predicted slope in colour-magnitude space, such determinations are heavily dependent on the assumed age of the cluster and complicated due to the large spreads in isochronal ages.

Palmese, A., O. Lahav, M. Banerji, D. Gruen, S. Jouvel, P. Melchior, J. Aleksić, et al. "Comparing Dark Energy Survey and HST–CLASH observations of the galaxy cluster RXC J2248.7−4431: implications for stellar mass versus dark matter." OXFORD UNIV PRESS, 2016. http://hdl.handle.net/10150/622739.

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We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f(star) = (6.8 +/- 1.7) x 10(-3) within a radius of r(200c) similar or equal to 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the similar to 100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.

Garcia, E. Victor, Thayne Currie, Olivier Guyon, Keivan G. Stassun, Nemanja Jovanovic, Julien Lozi, Tomoyuki Kudo, et al. "SCExAO AND GPI Y JH BAND PHOTOMETRY AND INTEGRAL FIELD SPECTROSCOPY OF THE YOUNG BROWN DWARF COMPANION TO HD 1160." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/623097.

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We present high signal-to-noise ratio, precise Y JH photometry and Y band (0.957-1.120 mu m) spectroscopy of HD 1160 B, a young substellar companion discovered from the Gemini NICI Planet Finding Campaign using the Subaru Coronagraphic Extreme Adaptive Optics instrument and the Gemini Planet Imager. HD 1160 B has typical mid-M dwarf-like infrared colors and a spectral type of M5.5(-0.5)(+1.0), where the blue edge of our Y band spectrum rules out earlier spectral types. Atmospheric modeling suggests HD 1160 B has an effective temperature of 3000-3100 K, a surface gravity of log g - 4-4.5, a radius of. 1.55 +/- 0.10 R-J, and a luminosity of log L/L circle dot - 2.76 +/- 0.05. Neither the primary's Hertzspring-Russell diagram position nor atmospheric modeling of HD 1160 B show evidence for a subsolar metallicity. Interpretation of the HD 1160 B spectroscopy depends on which stellar system components are used to estimate the age. Considering HD 1160 A, B and C jointly, we derive an age of 80-125 Myr, implying that HD 1160 B straddles the hydrogen-burning limit (70-90 M-J) If we consider HD 1160 A alone, younger ages (20-125 Myr) and a brown dwarf-like mass (35-90 M-J) are possible. Interferometric measurements of the primary, a precise Gaia parallax, and moderate-resolution spectroscopy can better constrain the system's age and how HD 1160 B fits within the context of (sub) stellar evolution.

Pagotto, Ilaria. "Mass determination of supermassive black holes in nearby galaxies." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3427292.

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This thesis focusses on the measure of the mass of supermassive black holes (SBH) lurking in the center of nearby quiescent galaxies. Increasing the demography of SBHs allows to study the correlations between their mass and the properties of their host to get insights about the joint evolution of SBHs and galaxies. New stringent limits on the SBH mass of 7 nearby galaxies are obtained by modeling the central width of the nebular emission lines measured over subarcsecond apertures with the Hubble Space Telescope (HST). The central stellar velocity dispersion of each galaxy is derived from new long-slit spectra from ground-based observations and the bulge effective radius is derived from a two-dimensional photometric decomposition of the i-band images from the Sloan Digital Sky Survey. The SBH-mass limits run parallel and above the relation between the SBH mass and the stellar velocity dispersion with no systematic trend depending on the galaxy distance or morphology. This gives further support to previous findings suggesting that the nuclear gravitational potential is remarkably well traced by the nebular-line width when the gas is centrally peaked. With this investigation, the number of galaxies with SBH-mass stringent limits obtained from nebular-line width increases to 114. These galaxies are further analyzed to more tightly constrain their SBH mass by taking into account the stellar mass contribution in the galaxy nucleus. To this aim the surface brightness distribution is measured from HST images and the mass-to-light ratio of an old and metal-rich stellar population is adopted for 100 nearby galaxies (D<103 Mpc) spanning a wide range of Hubble types (E-Sc) and central velocity dispersions (58-419 km/s). The shape of the profile of the emission lines and of the radial profile of emission-line flux are analysed to verify that nongravitational forces have a minor impact on the SBH-mass estimate. On average the stellar mass contribution is larger for galaxies with low effective velocity dispersion partly due to the presence of a nuclear stellar cluster or disk. Moreover, the stellar mass contribution is negligible in ellipticals and depends on the aperture size rather than on galaxy distance. These new SBH-mass limits run parallel to the relation between the SBH mass and the stellar velocity dispersion and they exceed the expected values by a median factor of 1.7. This is a striking result, since the dynamical analysis does not rely on spatially-resolved gas distribution and kinematics. Finally, new stellar velocity dispersions within subarcsecond apertures are obtained for the nuclei of a sample of 28 nearby galaxies. HST spectra obtained with the G750M grating are fitted using a library of single stellar population models and Gaussian emission lines, while constraining in most cases the stellar population content from an initial fit to HST G430L spectra. These measurements are useful for constraining the SBH mass as illustrated by the cases of the lenticular galaxies NGC 4435 and NGC 4459. These are characterized by similar ground-based stellar velocity dispersions but remarkably different SBH masses, where in particular NGC 4435 appears to host a significantly undermassive SBH compared to what expected from the relation between the SBH mass and stellar velocity dispersion. Jeans axisymmetric dynamical models are built to match the ground-based stellar kinematics obtained with integral-field spectroscopy assuming a SBH mass as predicted from the relation with the velocity dispersion and using high-resolution images as a base for constructing the stellar-mass model. Such reference models are used to make a prediction for the nuclear velocity dispersion. Whereas it agrees with the nuclear measurement for NGC 4459, for NGC 4435 the observed velocity dispersion is remarkably smaller than the predicted one, which further suggests that this galaxy hosts an undermassive SBH.
Questo lavoro di tesi è dedicato alla misura della massa dei buchi neri supermassicci (SBH) che si celano al centro delle galassie quiescenti vicine. Aumentare il campione di SBH di massa nota permette di studiarne le relazioni con le altre proprietà delle galassie per poterne investigare l'evoluzione congiunta. Nuovi limiti stringenti sulla massa del SBH di 7 galassie sono stati fissati dalla misura della larghezza delle righe nebulari del gas ionizzato in spettri presi con l'Hubble Space Telescope (HST) entro aperture di dimensioni inferiori al secondo d'arco. La dispersione di velocità delle stelle è stata misurata con spettri a fenditura lunga presi da terra e il raggio efficace è stato ricavato dalla decomposizione fotometrica di immagini della Sloan Digital Sky Survey. Questi limiti di massa si dispongono parallelamente e al di sopra della relazione tra la massa del SBH e la dispersione di velocità delle stelle e non dipendono dalla morfologia o dalla distanza delle galassie. Questo suggerisce che il potenziale gravitazionale nei nuclei galattici è ben tracciato dalla larghezza delle righe di emissione se il gas si concentra verso il centro. Il numero delle galassie con un limite sulla massa del SBH ricavato dalla larghezza delle righe di emissione sale così a 114 oggetti. Queste galassie sono state ulteriormente analizzate includendo nel modello dinamico il contributo della massa stellare per ottenere limiti ancora più stringenti sulla massa del SBH. A tale scopo la brillanza superficiale misurata da immagini HST e il rapporto massa-luminosità tipico di una popolazione stellare vecchia e ricca in metalli sono stati usati per 100 galassie vicine (D<100 Mpc) e con un'ampia varietà di morfologie (E-Sc) e dispersioni di velocità (58-419 km/s). La forma dei profili delle righe di emissione e dell'andamento radiale del loro flusso sono stati studiati per escludere che le forze non gravitazionali giocassero un ruolo rilevante nella stima della massa del SBH. Il contributo stellare è maggiore per galassie con bassa dispersione di velocità, anche per la presenza di un ammasso/disco stellare nucleare, e trascurabile per le ellittiche. Esso dipende dalle dimensioni dell'apertura ma non dalla distanza della galassia. I nuovi limiti di massa si dispongono parallelamente alla relazione tra la massa del SBH e la dispersione di velocità ed eccedono il valore predetto dalla medesima solo di un fattore 1.7. Questo è un risultato notevole visto che il modello dinamico si basa su una distribuzione e cinematica del gas non spazialmente risolte. Infine, sono state ottenute nuove misure di dispersione di velocità stellare nel nucleo di 28 galassie. Gli spettri HST ottenuti con il reticolo G750M sono stati interpolati con modelli di popolazioni stellari e varie righe di emissione gaussiane, vincolando la popolazione stellare nel nucleo delle galassie grazie a spettri presi con il reticolo G430L. Queste misure permettono di porre dei forti vincoli sulla massa del SBH come mostrano i casi di NGC 4435 e NGC 4459. Si tratta di due galassie lenticolari caratterizzate da valori simili di dispersione di velocità stellare ma con masse di SBH molto diverse. In particolare, quella di NGC 4435 è molto più bassa rispetto a quanto predetto dalla relazione tra la massa del SBH e la dispersione di velocità stellare. Grazie a modelli dinamici stellari assisimmetrici è stata riprodotta la cinematica ottenuta da spettroscopia a campo integrale usando immagini HST e adottando come massa del SBH quella predetta dalla relazione con la dispersione di velocità. Questi modelli permettono di predire il valore centrale di dispersione di velocità e di confrontarlo con il valore osservato. Mentre per NGC 4459 il valore teorico e quello osservato sono in accordo, il valore misurato per NGC 4435 è molto più basso rispetto che a quello del modello dinamico indicando che la galassia ospita un SBH meno massiccio del normale.

Randriamampandry, Solohery Mampionona. "Stellar masses of star forming galaxies in clusters." University of the Western Cape, 2010. http://hdl.handle.net/11394/3028.

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Magister Scientiae - MSc
We determine the stellar mass of star forming galaxies in the X-ray luminous cluster MS 0451.6-0305 at z ∼ 0.54. The stellar masses are estimated from fitting model spectral energy distributions (SEDs) to deep, optical UBRIz observations obtained from WIYN 3.5m telescope and public NIR K-band image from Palomar Observatory telescope. The model SEDs are based on the stellar population synthesis (SPS) model of Bruzual & Charlot (2003) and Conroy et al. (2009) that span a wide range of age, star formation history, Initial Mass Function (IMF), metallicity and dust content. We measure stellar masses for galaxies down to M∗∼2×10⁸M(.) We find a tight correlation between stellar masses derived from the two SPSs. We compare the derived stellar masses to the dynamical masses for a set of 25 star forming galaxies. The dynamical masses are derived from high resolution, spectroscopic observations of emission lines from the DEIMOS spectrograph on the Keck telescope. A strong correlation is seen between the dynamical and stellar mass for the galaxies; and the star forming galaxies show fairly constant ratio between stellar and dynamical mass. When comparing to the field sample of Guzm ́an et al. (2003) of luminous compact blue galaxies, we see an excess of low mass galaxies in the cluster.
South Africa

Czanik, Robert Johann. "An optical study of the high mass star forming region RCW 34 / Robert Johann Czanik." Thesis, North-West University, 2013. http://hdl.handle.net/10394/9102.

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This study consisted of an optical photometric and spectroscopic analysis on a 7′ 7′ field around the Southern high mass star forming region RCW 34. A previous study on RCW 34 in the NIR discov- ered many deeply embedded young stellar objects which were suspected to be T Tauri stars and which justified further investigation. The data used in this study consisted of three sets, the first two are photometric and spectroscopic data sets which were obtained during the first two weeks of February 2002. A third data set of spectroscopic observations was obtained by the author during the second week of 2011 of selected candidates using results from the NIR study and from the photometric data sets. All of the spectroscopy was conducted with the long slit spectrograph on the 1.9-m telescope and the photometry with DANDICAM on the 1.0-m telescope at the South African Astronomical Observatory (SAAO) in Sutherland. Objectives accomplished in the course of this study were to understand, ob- tain, reduce and interpret photometric and long slit spectroscopic CCD images. From the photometric results 57 stars showed excess blue emission on a colour-colour diagram which could be generated by circumstellar matter. The spectroscopic study showed 5 stars that showed H emission and 2 with strong Li absorption lines which confirm the suspicions of the NIR study about T Tauri stars in the region. All of the stars from the spectroscopic study in 2011 were identified as low-mass K or M type stars. Using colour-magnitude diagrams it was possible to see that the majority of the stars in the cluster are low-mass pre-main sequence stars. The stars matching between the optical and NIR filters were plotted on NIR colour-colour diagrams showing that the 5 stars that had H emission lines also had NIR colours characteristic to T Tauri stars. Out of the 5 stars that showed H emission, 2 were found to be classical T Tauris and three were found to be weak line T Tauris.
Thesis (MSc (Space Physics))--North-West University, Potchefstroom Campus, 2013

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Книги з теми "Mass photometry":

Photodetector development for the wheel abrasion experiment on the sojourner microrover of the Mars Pathfinder mission. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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Частини книг з теми "Mass photometry":

Bacon, R. "Mass-to-light ratio of elliptical galaxies." In New Aspects of Galaxy Photometry, 315–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/bfb0030967.

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Duval, M. F., and G. Monnet. "Mass to luminosity ratio of bars in spiral galaxies." In New Aspects of Galaxy Photometry, 323–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/bfb0030970.

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Héraudeau, Ph, F. Simien, and G. A. Mamon. "Mass Models from Near-Infrared Surface Photometry." In Spiral Galaxies in the Near-IR, 235–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-540-49739-4_35.

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Kent, S. "Photometry and Mass Modeling of Spiral Galaxies." In Nearly Normal Galaxies, 81–89. New York, NY: Springer New York, 1987. http://dx.doi.org/10.1007/978-1-4612-4762-3_11.

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von Hippel, T., G. Gilmore, and D. H. P. Jones. "HST Photometry of Low-Mass Stars in Open Clusters." In The Bottom of the Main Sequence — And Beyond, 201–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-540-49217-7_30.

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Malkov, Oleg. "Unresolved Binaries and the Initial Mass Function." In Census of the Galaxy: Challenges for Photometry and Spectrometry with GAIA, 129–32. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-010-0361-2_20.

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Smith, Myron A., and Lin Huang. "NRP Mode Typing for 53 Persei: Results From Voyager Photometry." In Pulsation, Rotation and Mass Loss in Early-Type Stars, 37–38. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1030-3_12.

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Ábrahám, P., Ch Leinert, D. Lemke, A. Burkert, and Th Henning. "Far-Infrared Photometry of Circumstellar Matter Around Intermediate Mass Stars." In Astrophysics and Space Science, 45–51. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5076-7_6.

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Jiménez-Esteban, F., D. Engels, P. García-Lario, and L. Agudo-Mérida. "Identification and NIR Photometry of the Arecibo Sample of OH/IR Stars." In Mass-Losing Pulsating Stars and their Circumstellar Matter, 223–24. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-010-0139-7_45.

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Fabregat, J., J. M. Torrejón, P. Reig, and G. Bernabeu. "Simultaneous uvbyβ Photometry and Hα Spectroscopy of Be Stars in Open Clusters." In Pulsation, Rotation and Mass Loss in Early-Type Stars, 309–10. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1030-3_84.

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Тези доповідей конференцій з теми "Mass photometry":

Seleznev, A. F., and A. A. Malofeeva. "A search of unresolved binaries in open clusters by the photometry data in visible and infrared." In ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021. Crossref, 2022. http://dx.doi.org/10.51194/vak2021.2022.1.1.194.

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The general idea is to ﬁnd the photometric diagram where the unresolved binary stars are well detached from the singlestars, even for small values of the component mass ratio q. We use the diagram (H-W2)-W1—W2-(BP-K) to estimate thebinary and multiple star ratio and the distribution of q for the Pleiades in the primary component mass interval between0.5 and 1.8 solar masses. A large number of binaries with secondary components being brown dwarfs or stars with theremnants of protostellar discs providing slight infrared excess are among the low-mass stars with the mass of the primarycomponent lower than 0.5 solar masses.

Demianenko, M., K. Grishin, V. Toptun, I. Chilingarian, I. Katkov, V. Goradzhanov, and I. Kuzmin. "Optical light curves of light-weight supermassive black holes produced by the Zwicky Transient Facility Forced Photometry Service." In ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021. Crossref, 2022. http://dx.doi.org/10.51194/vak2021.2022.1.1.144.

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In this paper, we present an algorithm to correct optical light curves obtained using The Zwicky Transient Facility ForcedPhotometry Service and its application to the analysis of optical variability of 136 actvie galactic nuclei (AGN) pow-ered by “light-weight” supermassive black holes (SMBH; M BH < 2 ∗ 10 6 , M ⊙ ) including 24 intermediate-mass black holes(IMBH; M BH < 2 ∗ 10 5 , M ⊙ ). We detected variability in nearly all sources and also analyzed its dependence on theX-ray luminosity for 101 objects. We also identiﬁed a previously unknown candidate tidal disruption event (TDE) inSDSS J112637.74+513423.0.

Northrop, William F., Darrick Zarling, and Xuesong Li. "Considerations in Using Photometer Instruments for Measuring Total Particulate Matter Mass Concentration in Diesel Engine Exhaust." In ASME 2017 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icef2017-3640.

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In this work, engine-out particulate matter (PM) mass emissions from an off-highway diesel engine measured using a low-cost photometer, scanning mobility particle sizer, elemental versus organic carbon analysis, and a photo-acoustic analyzer are compared. Tested engine operating modes spanned the range of those known to result in high semi-volatile particle concentration and those that emit primarily solid particles. Photometer measurements were taken following a primary dilution stage and a sample conditioner to control relative humidity prior to the instrument. Results of the study show that the photometer could qualitatively track total particle mass trends over the tested engine conditions though it was not accurate in measuring total carbon mass concentration. Further, the required photometric calibration factor (PCF) required to accurately measure total PM mass changes with the organic carbon (OC) fraction of the particles. Variables that influence PCF include particle effective density, which changes both as a function of particle diameter and OC fraction. Differences in refractive index between semi-volatile and solid particles are also significant and contribute to high error associated with measurement of total PM using the photometer. This work illustrates that it may be too difficult to accurately measure total engine PM mass with a photometer without knowing additional information about the sampled particles. However, removing semi-volatile organic materials prior to the instrument may allow the accurate estimation of elemental carbon mass concentration alone.

Gontcharov, G., A. Mosenkov, M. Khovritchev, V. Il’in, A. Marchuk, S. Savchenko, A. Smirnov, and P. Usachev. "The properties of Galactic globular clusters from Gaia EDR3 and other data compared with theoretical isochrones." In ASTRONOMY AT THE EPOCH OF MULTIMESSENGER STUDIES. Proceedings of the VAK-2021 conference, Aug 23–28, 2021. Crossref, 2022. http://dx.doi.org/10.51194/vak2021.2022.1.1.182.

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We ﬁt theoretical isochrones from diﬀerent models of internal structure and evolution of stars to photometric data for thestars in globular clusters of our Galaxy. To select cluster members, determine cluster sizes and calculate systemic propermotions, we use parallaxes and proper motions from Gaia EDR3. To calculate the most probable distance, age, interstellarextinction in a variety of ﬁlters and diﬀerential reddening in cluster ﬁelds, we use photometry in more than 26 ﬁlters betweenthe ultraviolet and mid-infrared waverange from HST, Gaia EDR3, Pan-STARRS DR1, DES, SDSS, unWISE, SAGE andother datasets in combination with the PARSEC, MIST, DSEP, and BaSTI-IAC isochrones, as for the solar metallicityscale as for alpha- and helium-enriched scales. The metallicity and enrichment of the clusters is taken from spectroscopicobservations and tested for compliance with the photometric results. We carry out a thorough analysis of random andsystematic uncertainties of the obtained results. The derived extinctions in many ﬁlters allow us to estimate an empiricalextinction law for each cluster. A complete analysis has been performed for ﬁve clusters (NGC288, NGC362, NGC5904,NGC6205, and NGC6218), a preliminary analysis, based on the Gaia EDR3 astrometry and photometry only, has beendone for 38 more clusters. The main conclusions are as follows. First, unprecedentedly accurate astrometry of Gaia EDR3allows us to segregate the cluster members from fore- and background stars and to indicate that the size of many clustersis much larger than previously thought. Second, the distances, derived by us from the photometry-to-isochrone ﬁtting, arestill more precise than distances from the Gaia EDR3 parallaxes. Third, contrary to the popular 2D reddening maps ofSchlegel-1998 and Planck, we found no clusters at high Galactic latitudes with an extinction A V < 0.1. Fourth, for thehorizontal branch second parameter quartet NGC 288–NGC 362–NGC 5904–NGC 6218, the age is undoubtedly the secondparameter.

Bruce, Sally. "The NIST Quality System for Measurement Services: A look at its Past Decade and a Gaze towards its Future." In NCSL International Workshop & Symposium. NCSL International, 2013. http://dx.doi.org/10.51843/wsproceedings.2013.38.

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A Look at its Past Decade and a Gaze towards its Future. As the National Metrology Institute (NMI) for the United States, the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards, has provided measurement services, both calibrations and reference materials, for more than 100 years. Through these services, our customers have benefitted from our measurement capabilities and expertise in many areas, including amount of substance; dimensional metrology; electricity and magnetism; ionizing radiation; mass and related quantities; photometry and radiometry; thermodynamics; and time and frequency. NIST’s customers have also had access to some of the lowest measurement uncertainties available and a dependable way to establish traceability to the International System of Units (SI) [http://www.nist.gov/pml/wmd/metric/si-units.cfm].In response to the signing of the International Committee for Weights and Measures (CIPM) Mutual Recognition Arrangement (MRA), NIST first established an institution-wide quality system for the measurement services 10 years ago [http://www.bipm.org/en/cipm-mra/objectives.html]. NIST’s Quality System for Measurement Services has advanced the quality of service and measurements we provide our customers by fostering an environment in which NIST management and staff work towards continual improvement in the development and delivery of NIST measurement services. This paper describes NIST’s Quality System for the Measurement Services and its relevance to international standards of quality, such as the International Organization for Standardization and the International Electrotechnical Commission (ISO/IEC) 17025 standard and ISO Guide 34 [http://www.nist.gov/nistqs/]. It also provides a history of this quality system and a glimpse of future goals for improving its implementation.

van Rijswick, Mathieu H. "Photometry maps to characterize incandescent and halogen lamps." In International Symposium on Optical Science and Technology, edited by C. Benjamin Wooley. SPIE, 2002. http://dx.doi.org/10.1117/12.479657.

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Abahamid, A., M. Sarazin, and G. Lombardi. "Photometric study of the Paranal observatory using MASS database." In SPIE Astronomical Telescopes + Instrumentation, edited by Suzanne K. Ramsay, Ian S. McLean, and Hideki Takami. SPIE, 2014. http://dx.doi.org/10.1117/12.2066652.

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Ikehata, Satoshi. "Scalable, Detailed and Mask-Free Universal Photometric Stereo." In 2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition (CVPR). IEEE, 2023. http://dx.doi.org/10.1109/cvpr52729.2023.01268.

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Chatterjee, Avishek, and Venu Madhav Govindu. "Photometric refinement of depth maps for multi-albedo objects." In 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR). IEEE, 2015. http://dx.doi.org/10.1109/cvpr.2015.7298695.

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Qi, Haiyang, Sumei Liu, Sunqiang Pan, Pengbing Hu, and Chonghui Chen. "Study on calibration of mask protective effect detector of mask based on precise photometer." In Optics in Health Care and Biomedical Optics XI, edited by Qingming Luo, Xingde Li, Ying Gu, and Dan Zhu. SPIE, 2021. http://dx.doi.org/10.1117/12.2600681.

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Звіти організацій з теми "Mass photometry":

Sedlacek, Arthur, and Robert Jackson. Single-Particle Soot Photometer (SP2) Black Carbon Number and Mass Concentrations. Office of Scientific and Technical Information (OSTI), April 2024. http://dx.doi.org/10.2172/2341496.

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Ortiz, M. Growing Self-Organizing Maps as Predictors for Photometric Redshift. Office of Scientific and Technical Information (OSTI), August 2019. http://dx.doi.org/10.2172/1557954.

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Mayer, B. P., A. M. Williams, R. N. Leif, and A. K. Vu. Extraction of Phosphonic Acids from Urine Samples and Analysis by Gas Chromatography with Detection by Mass Spectrometryand Flame Photometric Detection. Office of Scientific and Technical Information (OSTI), December 2013. http://dx.doi.org/10.2172/1116967.

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Longworth, Terri L., John M. Baranoski, and Kwok Y. Ong. Domestic Preparedness Program: Evaluation of the Agilent Gas Chromatograph - Flame Photometric Detector/Mass Selective Detector (GC-FPD/MSD) System Against Chemical Warfare Agents Summary Report. Fort Belvoir, VA: Defense Technical Information Center, May 2003. http://dx.doi.org/10.21236/ada416884.

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Amirav, Aviv, and Steven Lehotay. Fast Analysis of Pesticide Residues in Agricultural Products. United States Department of Agriculture, November 2002. http://dx.doi.org/10.32747/2002.7695851.bard.

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The overall theme of this project was to increase the speed of analysis for monitoring pesticide residues in food. Traditionally, analytical methods for multiple pesticides are time-consuming, expensive, laborious, wasteful, and ineffective to meet critical needs related to food safety. Faster and better methods were needed to provide more cost-effective detection of chemical contaminants, and thus provide a variety of benefits to agriculture. This overarching goal to speed and improve pesticide analysis was successfully accomplished even beyond what was originally proposed by the investigators in 1998. At that time, the main objectives of this project were: 1) to further develop a direct sample introduction (DSI) device that enables fast sampling and introduction of blended-only agricultural products for analysis by gas chromatography (GC); 2) to evaluate, establish, and further develop the method of simultaneous pulsed flame photometric detector (PFPD) and mass spectrometry (MS) detection for enhanced pesticide identification capabilities; and 3) to develop a new and novel MS pesticide analysis method, based on the use of supersonic molecular beams (SMB) for sampling and ionization. The first and third objectives were successfully accomplished as proposed, and the feasibility of the second objective was already demonstrated. The capabilities of the GC/SMB-MS approach alone were so useful for pesticide analysis that the simultaneous use of a PFPD was considered superfluous. Instead, the PFPD was investigated in combination with an electron-capture detector for low-cost, simultaneous analysis of organophosphorus and organochlorine pesticides in fatty foods. Three important, novel research projects not originally described in the proposal were also accomplished: 1) development of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticides in foods; 2) development and optimization of a method using low-pressure (LP) GC/MS to speed pesticide residue analysis; and 3) innovative application of analyte protectants to improve the GC analysis of important problematic pesticides. All of the accomplishments from this project are expected to have strong impact to the analytical community and implications to agriculture and food safety. For one, an automated DSI approach has become commercially available in combination with GC/MS for the analysis of pesticide residues. Meanwhile, the PFPD has become the selective detector of choice for the analysis of organophosphorus pesticides. Great strides were made in SMB-MS through the manufacture of a prototype "Supersonic GC/MS" instrument, which displayed many advantages over commercial GC/MS instruments. Most notably, the QuEChERS method is already being disseminated to routine monitoring labs and has shown great promise to improve pesticide analytical capabilities and increase lab productivity. The implications of these developments to agriculture will be to increase the percentage of food monitored and the scope of residues detected in the food, which will serve to improve food safety. Developed and developing countries alike will be able to use these methods to lower costs and improve results, thus imported/exported food products will have better quality without affecting price or availability. This will help increase trade between nations and mitigate certain disputes over residue levels in imported foods. The improved enforcement of permissible residue levels provided by these methods will have the effect to promote good agricultural practices among previously obstinate farmers who felt no repercussions from illegal or harmful practices. Furthermore, the methods developed can be used in the field to analyze samples quickly and effectively, or to screen for high levels of dangerous chemicals that may intentionally or accidentally appear in the food supply.