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Sample records for emission line diagnostics

  1. Iron Line Diagnostics of Narrow Emission Line Galaxies

    NASA Astrophysics Data System (ADS)

    Nousek, John A.

    1996-05-01

    This report describes the activities at Penn State University supported by NASA Grant NAG5-2528, 'Iron Line Diagnostics of Narrow Emission Line Galaxies'. The aim of this investigation was to accurately measure the iron (Fe K) line emission in two X-ray selected Seyfert 2 galaxies (NGC 2992 and MCG-5-23-16). The astrophysics being probed was to determine whether the Fe line was narrow, broad or both. The broad line component is very important as a probe of the nature of the innermost accretion onto the central engine in AGN's.

  2. Polarization diagnostics for cool core cluster emission lines

    SciTech Connect

    Sparks, W. B.; Pringle, J. E.; Cracraft, M.; Meyer, E. T.; Carswell, R. F.; Voit, G. M.; Donahue, M.; Hough, J. H.; Manset, N.

    2014-01-01

    The nature of the interaction between low-excitation gas filaments at ∼10{sup 4} K, seen in optical line emission, and diffuse X-ray emitting coronal gas at ∼10{sup 7} K in the centers of galaxy clusters remains a puzzle. The presence of a strong, empirical correlation between the two gas phases is indicative of a fundamental relationship between them, though as yet of undetermined cause. The cooler filaments, originally thought to have condensed from the hot gas, could also arise from a merger or the disturbance of cool circumnuclear gas by nuclear activity. Here, we have searched for intrinsic line emission polarization in cool core galaxy clusters as a diagnostic of fundamental transport processes. Drawing on developments in solar astrophysics, direct energetic particle impact induced polarization holds the promise to definitively determine the role of collisional processes such as thermal conduction in the ISM physics of galaxy clusters, while providing insight into other highly anisotropic excitation mechanisms such as shocks, intense radiation fields, and suprathermal particles. Under certain physical conditions, theoretical calculations predict of the order of 10% polarization. Our observations of the filaments in four nearby cool core clusters place stringent upper limits (≲ 0.1%) on the presence of emission line polarization, requiring that if thermal conduction is operative, the thermal gradients are not in the saturated regime. This limit is consistent with theoretical models of the thermal structure of filament interfaces.

  3. Galaxy evolution across the optical emission-line diagnostic diagrams?

    NASA Astrophysics Data System (ADS)

    Vitale, M.; Fuhrmann, L.; García-Marín, M.; Eckart, A.; Zuther, J.; Hopkins, A. M.

    2015-01-01

    Context. The discovery of the M - σ relation, the local galaxy bimodality, and the link between black-hole and host-galaxy properties have raised the question of whether active galactic nuclei (AGN) play a role in galaxy evolution. AGN feedback is one of the biggest observational challenges of modern extragalactic astrophysics. Several theoretical models implement AGN feedback to explain the observed galaxy luminosity function and, possibly, the color and morphological transformation of spiral galaxies into passive ellipticals. Aims: For understanding the importance of AGN feedback, a study of the AGN populations in the radio-optical domain is crucial. A mass sequence linking star-forming galaxies and AGN has already been noted in previous works, and it is now investigated as a possible evolutionary sequence. Methods: We observed a sample of 119 intermediate-redshift (0.04 ≤ z< 0.4) SDSS-FIRST radio emitters with the Effelsberg 100-m telescope at 4.85 and 10.45 GHz and obtained spectral indices. The sample includes star-forming galaxies, composite galaxies (with mixed contribution to line emission from star formation and AGN activity), Seyferts, and low ionization narrow emission region (LINER) galaxies. With these sources we search for possible evidence of spectral evolution and a link between optical and radio emission in intermediate-redshift galaxies. Results: We find indications of spectral index flattening in high-metallicity star-forming galaxies, composite galaxies, and Seyferts. This "flattening sequence" along the [NII]-based emission-line diagnostic diagram is consistent with the hardening of galaxy ionizing field, thanks to nuclear activity. After combining our data with FIRST measurements at 1.4 GHz, we find that the three-point radio spectra of Seyferts and LINERs show substantial differences, which are attributable to small radio core components and larger (arcsecond sized) jet/lobe components, respectively. A visual inspection of FIRST images

  4. Nuclear activity versus star formation: emission-line diagnostics at ultraviolet and optical wavelengths

    NASA Astrophysics Data System (ADS)

    Feltre, A.; Charlot, S.; Gutkin, J.

    2016-03-01

    In the context of observations of the rest-frame ultraviolet and optical emission from distant galaxies, we explore the emission-line properties of photoionization models of active and inactive galaxies. Our aim is to identify new line-ratio diagnostics to discriminate between gas photoionization by active galactic nuclei (AGN) and star formation. We use a standard photoionization code to compute the emission from AGN narrow-line regions and compare this with calculations of the nebular emission from star-forming galaxies achieved using the same code. We confirm the appropriateness of widely used optical spectral diagnostics of nuclear activity versus star formation and explore new diagnostics at ultraviolet wavelengths. We find that combinations of a collisionally excited metal line or line multiplet, such as C IV λλ1548, 1551, O III] λλ1661, 1666, N III] λ1750, [Si III] λ1883+Si III] λ1892 and [C III] λ1907+C III] λ1909, with the He II λ1640 recombination line are individually good discriminants of the nature of the ionizing source. Diagrams involving at least three of these lines allow an even more stringent distinction between active and inactive galaxies, as well as valuable constraints on interstellar gas parameters and the shape of the ionizing radiation. Several line ratios involving Ne-based emission lines, such as [Ne IV] λ2424, [Ne III] λ3343 and [Ne V] λ3426, are also good diagnostics of nuclear activity. Our results provide a comprehensive framework to identify the sources of photoionization and physical conditions of the ionized gas from the ultraviolet and optical nebular emission from galaxies. This will be particularly useful to interpret observations of high-redshift galaxies with future facilities, such as the James Webb Space Telescope and extremely large ground-based telescopes.

  5. Luminosity Dependence and Redshift Evolution of Strong Emission-Line Diagnostics in Star-Forming Galaxies

    NASA Astrophysics Data System (ADS)

    Cowie, L. L.; Barger, A. J.; Songaila, A.

    2016-01-01

    We examine the redshift evolution of standard strong emission-line diagnostics for Hβ-selected star-forming galaxies using the local SDSS sample and a new z=0.2{--}2.3 sample obtained from Hubble Space Telescope WFC3 grism and Keck DEIMOS and MOSFIRE data. We use the SDSS galaxies to show that there is a systematic dependence of the strong emission-line properties on Balmer-line luminosity, which we interpret as showing that both the N/O abundance and the ionization parameter increase with increasing line luminosity. Allowing for the luminosity dependence tightens the diagnostic diagrams and the metallicity calibrations. The combined SDSS and high-redshift samples show that there is no redshift evolution in the line properties once the luminosity correction is applied, i.e., all galaxies with a given L({{H}}β ) have similar strong emission-line distributions at all the observed redshifts. We argue that the best metal diagnostic for the high-redshift galaxies may be a luminosity-adjusted version of the [N ii]6584/Hα metallicity relation. Based in part on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA and was made possible by the generous financial support of the W. M. Keck Foundation.

  6. GAS EXCITATION IN ULIRGs: MAPS OF DIAGNOSTIC EMISSION-LINE RATIOS IN SPACE AND VELOCITY

    SciTech Connect

    Soto, Kurt T.; Martin, Crystal L.

    2012-11-15

    Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of H{alpha}, [N II], [S II], [O I], H{beta}, and [O III] are resolved and fit jointly with common velocity components. Diagnostic ratios of these line fluxes are presented in a series of plots, showing how the Doppler shift, line width, gas excitation, and surface brightness change with velocity at fixed position and also with distance from the nucleus. One general characteristic of these spectra is the presence of shocked gas extending many kiloparsecs from the nucleus. In some systems, the rotation curves of the emitting gas indicate motions that suggest gas disks, which are most frequent at early merger stages. At these early merger stages, the emission line ratios indicate the presence of shocked gas, which may be triggered by the merger event. We also report the general characteristics of the integrated spectra.

  7. Chemical abundances in high-redshift galaxies: a powerful new emission line diagnostic

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.; Kewley, Lisa J.; Sutherland, Ralph S.; Nicholls, David C.

    2016-02-01

    This Letter presents a new, remarkably simple diagnostic specifically designed to derive chemical abundances for high redshift galaxies. It uses only the Hα, [N ii] and [S ii] emission lines, which can usually be observed in a single grating setting, and is almost linear up to an abundance of 12+log (O/H) = 9.05. It can be used over the full abundance range encountered in high redshift galaxies. By its use of emission lines located close together in wavelength, it is also independent of reddening. Our diagnostic depends critically on the calibration of the N/O ratio. However, by using realistic stellar atmospheres combined with the N/O vs. O/H abundance calibration derived locally from stars and H ii regions, and allowing for the fact that high-redshift H ii regions have both high ionisation parameters and high gas pressures, we find that the observations of high-redshift galaxies can be simply explained by the models without having to invoke arbitrary changes in N/O ratio, or the presence of unusual quantities of Wolf-Rayet stars in these galaxies.

  8. Database of emission lines

    NASA Astrophysics Data System (ADS)

    Binette, L.; Ortiz, P.; Joguet, B.; Rola, C.

    1998-11-01

    A widely accessible data bank (available through Netscape) and consiting of all (or most) of the emission lines reported in the litterature is being built. It will comprise objects as diverse as HII regions, PN, AGN, HHO. One of its use will be to define/refine existing diagnostic emission line diagrams.

  9. Adding Emission Line Diagnostics To The Infrared Database of Extragalactic Observables from Spitzer (IDEOS)

    NASA Astrophysics Data System (ADS)

    Spoon, Henrik

    During the cryogenic phase of the successful Spitzer mission the Infrared Spectrograph (IRS) made observations of about 15,000 objects. Among these are low-resolution (highresolution) spectra of more than 4200 (1800) galaxies beyond the Local Group. Results have been published in a great number of papers, led not only by hardcore infrared observers but increasingly also by non-native infrared astronomers. As the PI team of the IRS instrument, we are especially proud of the achievements of the IRS spectrograph, and we feel a special obligation to enhance the legacy value of its many observations. In 2011 we completed the Cornell Atlas of Spitzer-IRS Sources (CASSIS), containing homogeneously, expert-reduced low-resolution IRS spectra for over 13,000 observations. Earlier this year we added more than 7,000 spectra obtained with the high-resolution modules. All of these spectra benefit from the availability of our empirically derived super-sampled point-spread functions, which reduce the effects of bad and low-level rogue pixels in all IRS modules. All spectra are available for download from our CASSIS web portal. Building on this legacy, in 2013 we also started working on the soon to be completed Infrared Database of Extragalactic Observables from Spitzer (IDEOS), which contains mid-IR observables extracted from the low-resolution spectra in CASSIS. IDEOS provides astronomers with widely varying scientific interests access to diagnostics that were previously available only for limited samples, or available on the-fly only to expert users. Here we propose to continue these efforts by measuring the emission line fluxes for 3,000-4,500 galaxies in the CASSIS atlas to add powerful emission line diagnostics to our existing suite of mid-IR observables in IDEOS. IDEOS will be a great asset for future users of NASA's James Webb Space Telescope to select their samples and estimate required integration times. The completion of IDEOS will further coincide with the completion of

  10. Upgrading electron temperature and electron density diagnostic diagrams of forbidden line emission

    NASA Astrophysics Data System (ADS)

    Proxauf, B.; Öttl, S.; Kimeswenger, S.

    2014-01-01

    Context. Diagnostic diagrams of forbidden lines have been a useful tool for observers for many decades now. They are used to obtain information on the basic physical properties of thin gaseous nebulae. Some diagnostic diagrams are in wavelength domains that were difficult to apply either due to missing wavelength coverage or the low resolution of older spectrographs. Furthermore, most of the diagrams were calculated using just the species involved as a single atom gas, although several are affected by well-known fluorescence mechanisms as well. Additionally, the atomic data have improved up to the present time. Aims: The aim of this work is to recalculate well-known, but also sparsely used, unnoted diagnostics diagrams. The new diagrams provide observers with modern, easy-to-use recipes for determining electron temperature and densities. Methods: The new diagnostic diagrams were calculated using large grids of parameter space in the photoionization code CLOUDY. For a given basic parameter (e.g., electron density or temperature), the solutions with cooling-heating-equilibrium were chosen to derive the diagnostic diagrams. Empirical numerical functions were fitted to provide formulas usable in, e.g., data reduction pipelines. Results: The resulting diagrams differ significantly from those used up to now and will improve thermodynamic calculations. To our knowledge, detailed, directly applicable fit formulas are given for the first time, leading to the calculation of electron temperature or density from the line ratios.

  11. Mid-IR Properties of an Unbiased AGN Sample of the Local Universe. 1; Emission-Line Diagnostics

    NASA Technical Reports Server (NTRS)

    Weaver, K. A.; Melendez, M.; Muhotzky, R. F.; Kraemer, S.; Engle, K.; Malumuth. E.; Tueller, J.; Markwardt, C.; Berghea, C. T.; Dudik, R. P.; Winter, L. M.; Armus, L.

    2010-01-01

    \\Ve compare mid-IR emission-lines properties, from high-resolution Spitzer IRS spectra of a statistically-complete hard X-ray (14-195 keV) selected sample of nearby (z < 0.05) AGN detected by the Burst Alert Telescope (BAT) aboard Swift. The luminosity distribution for the mid-infrared emission-lines, [O IV] 25.89 microns, [Ne II] 12.81 microns, [Ne III] 15.56 microns and [Ne V] 14.32 microns, and hard X-ray continuum show no differences between Seyfert 1 and Seyfert 2 populations, although six newly discovered BAT AGNs are shown to be under-luminous in [O IV], most likely the result of dust extinction in the host galaxy. The overall tightness of the mid-infrared correlations and BAT luminosities suggests that the emission lines primarily arise in gas ionized by the AGN. We also compared the mid-IR emission-lines in the BAT AGNs with those from published studies of star-forming galaxies and LINERs. We found that the BAT AGN fall into a distinctive region when comparing the [Ne III]/[Ne II] and the [O IV]/[Ne III] quantities. From this we found that sources that have been previously classified in the mid-infrared/optical as AGN have smaller emission line ratios than those found for the BAT AGNs, suggesting that, in our X-ray selected sample, the AGN represents the main contribution to the observed line emission. Overall, we present a different set of emission line diagnostics to distinguish between AGN and star forming galaxies that can be used as a tool to find new AGN.

  12. Development of a Temperature Diagnostic Based on the Emission Lines of Fluorine-Like Ions

    NASA Astrophysics Data System (ADS)

    Lepson, Jaan K.; Beiersdorfer, Peter; Kaita, Robert; Majeski, Richard; Boyle, Dennis

    2016-06-01

    We used the Flexible Atomic Code to calculate theoretical intensities of extreme ultraviolet emission lines of fluorine-like Al IV, Si VI, and S VIII at electron temperatures Te from 1 eV to well above 100 eV, and found that the intensity ratio of the 3-->2 and 2-->2 transitions is temperature sensitive. We tested these calculations by measuring the relevant Al IV emission in the 115-320 Å spectral region on the Lithium Tokamak Experiment at the Princeton Plasma Physics Laboratory. Spectra were taken with the Long Wavelength Extreme Ultraviolet Spectrometer, LoWEUS, which has a resolution of ~0.3 Å. We identified emission from neon-like Al V as well as fluorine-like Al IV. Our data include emission from Li II and Li III, and O IV-VI, which we used for wavelength calibration. We used the oxygen line intensities from CHIANTI to calculate the intensity response function for the region we studied. The measurements confirm that the ratio of the intensity of the 3-->2 feature at 133 Å to a pair of 2-->2 lines at 278 Å and 281 Å can be used to derive temperature estimates for the emitting region of the plasma. Our measurements indicate a temperature Te of ~16 ± 2 eV from the 133/278 Å line pair and ~17.5 ±2 eV from the 133/281 Å line pair, which is close to the temperature of maximum abundance of fluorine-like Al.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the U.S. Department of Energy Basic Plasma Science Program.

  13. Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device

    SciTech Connect

    Fujii, K.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2013-01-15

    We observe the Balmer-{alpha}, -{beta}, and -{gamma} lines of hydrogen atoms and Q branches of the Fulcher-{alpha} band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 {approx} 20 eV, while the rotational temperature of molecules is {approx}0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-{alpha} line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there.

  14. Modelling the Pan-Spectral Energy Distribution of Starburst Galaxies: III. Emission Line Diagnostics of Ensembles of H II Regions

    SciTech Connect

    Dopita, M A; Fischera, J; Sutherland, R S; Kewley, L J; Leitherer, C; Tuffs, R J; Popescu, C C; van Breugel, W; Groves, B A

    2006-05-10

    We have built, as far as possible, fully self-consistent models of H II regions around aging clusters of stars. These produce strong emission line diagnostics applicable to either individual H II regions in galaxies, or to the integrated emission line spectra of disk or starburst galaxies. The models assume that the expansion and internal pressure of individual H II regions is driven by the net input of mechanical energy from the central cluster, be it through winds or supernova events. This eliminates the ionization parameter as a free variable, replacing it with a parameter which depends on the ratio of the cluster mass to the pressure in the surrounding interstellar medium. These models explain why H II regions with low abundances have high excitation, and demonstrate that at least part of the warm ionized medium is the result of overlapping faint, old, large, and low pressure H II regions. We present a number of line ratios (at both optical and IR wavelengths) that provide reliable abundance diagnostics for either single H II regions or for integrated galaxy spectra, and others that are sensitive to the age of the cluster stars exciting individual H II regions.

  15. Emission Signatures from Sub-parsec Binary Supermassive Black Holes. I. Diagnostic Power of Broad Emission Lines

    NASA Astrophysics Data System (ADS)

    Nguyen, Khai; Bogdanović, Tamara

    2016-09-01

    Motivated by advances in observational searches for sub-parsec supermassive black hole binaries (SBHBs) made in the past few years, we develop a semi-analytic model to describe spectral emission-line signatures of these systems. The goal of this study is to aid the interpretation of spectroscopic searches for binaries and to help test one of the leading models of binary accretion flows in the literature: SBHB in a circumbinary disk. In this work, we present the methodology and a comparison of the preliminary model with the data. We model SBHB accretion flows as a set of three accretion disks: two mini-disks that are gravitationally bound to the individual black holes and a circumbinary disk. Given a physically motivated parameter space occupied by sub-parsec SBHBs, we calculate a synthetic database of nearly 15 million broad optical emission-line profiles and explore the dependence of the profile shapes on characteristic properties of SBHBs. We find that the modeled profiles show distinct statistical properties as a function of the semimajor axis, mass ratio, eccentricity of the binary, and the degree of alignment of the triple disk system. This suggests that the broad emission-line profiles from SBHB systems can in principle be used to infer the distribution of these parameters and as such merit further investigation. Calculated profiles are more morphologically heterogeneous than the broad emission lines in observed SBHB candidates and we discuss improved treatment of radiative transfer effects, which will allow a direct statistical comparison of the two groups.

  16. VIMOS integral field spectroscopy of blue compact galaxies. I. Morphological properties, diagnostic emission-line ratios, and kinematics

    NASA Astrophysics Data System (ADS)

    Cairós, L. M.; Caon, N.; Weilbacher, P. M.

    2015-05-01

    Context. Blue compact galaxies (BCG) are gas-rich, low-luminosity, low-metallicity systems that undergo a violent burst of star formation. These galaxies offer us a unique opportunity to investigate collective star formation and its effects on galaxy evolution in a relatively simple environment. Spatially resolved spectrophotometric studies of BCGs are essential for a better understanding of the role of starburst-driven feedback processes on the kinematical and chemical evolution of low-mass galaxies near and far. Aims: We carry out an integral field spectroscopic study of a sample of BCGs, with the aim of probing the morphology, kinematics, dust extinction, and excitation mechanisms of their warm interstellar medium. Methods: Eight BCGs were observed with the VIMOS integral field unit at the Very Large Telescope using blue and orange grisms in high-resolution mode. At a spatial sampling of 0''&dotbelow;67 per spaxel, we covered about 30″ × 30″ on the sky, with a wavelength range of 4150...7400 Å. Emission lines were fitted with a single Gaussian profile to measure their wavelength, flux, and width. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines, as well as diagnostic line ratios, extinction, and kinematic maps. Results: An atlas has been produced with the following: emission-line fluxes and continuum emission; ionization, interstellar extinction, and electron density maps from line ratios; velocity and velocity dispersion fields. From integrated spectroscopy, it includes tables of the extinction corrected line fluxes and equivalent widths, diagnostic-line ratios, physical parameters, and the abundances for the brightest star-forming knots and for the whole galaxy. Based on observations made with ESO Telescopes at the Paranal Observatory under program ID 079.B-0445.The reduced datacubes and their error maps (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp

  17. Fe Line Diagnostics of Cataclysmic Variables and Galactic Ridge X-Ray Emission

    NASA Astrophysics Data System (ADS)

    Xu, Xiao-jie; Wang, Q. Daniel; Li, Xiang-Dong

    2016-02-01

    The properties of the Galactic Ridge X-ray Emission (GRXE) observed in the 2-10 keV band place fundamental constraints on various types of X-ray sources in the Milky Way. Although the primarily discrete origin of the emission is now well established, the responsible populations of these sources remain uncertain, especially at relatively low fluxes. To provide insights into this issue, we systematically characterize the Fe emission line properties of the candidate types of the sources in the solar neighborhood and compare them with those measured for the GRXE. Our source sample includes 6 symbiotic stars, 16 intermediate polars (IPs), 3 polars, 16 quiescent dwarf novae, and 4 active binaries (ABs); they are all observed with the Suzaku X-ray Observatory. The data of about one-fourth of these sources are analyzed for the first time. We find that the mean equivalent width (EW6.7) of the 6.7 keV line and the mean 7.0/6.7 keV line ratio are 107 ± 16.0 eV and 0.71 ± 0.04 for IPs and 221 ± 135 eV and 0.44 ± 0.14 for polars, respectively, which are all substantially different from those (490 ± 15 eV and 0.2 ± 0.08) for the GRXE. Instead, the GRXE values are better agreed by the EW6.7 (438 ± 84.6 eV) and the ratio (0.27 ± 0.06) observed for the DNe. We further find that the EW6.7 is strongly correlated with the 2-10 keV luminosity of the DNe, which can be characterized by the relation {{EW}}6.7={(438+/- 95{{eV}})(L/{10}31{erg}{{{s}}}-1)}(-0.31+/- 0.15). Accounting for this correlation, the agreement can be improved further, especially when the contributions from other class sources to the GRXE are considered, which all have low EW6.7 values. We conclude that the GRXE mostly consists of typically faint but numerous DNe, plus ABs, while magnetic cataclysmic variables are probably mainly the high-flux representatives of the responsible populations and dominate the GRXE only in harder energy bands.

  18. Real-time control of tearing modes using a line-of-sight electron cyclotron emission diagnostic

    NASA Astrophysics Data System (ADS)

    Hennen, B. A.; Westerhof, E.; Nuij, P. W. J. M.; Oosterbeek, J. W.; de Baar, M. R.; Bongers, W. A.; Bürger, A.; Thoen, D. J.; Steinbuch, M.; TEXTOR Team

    2010-10-01

    The stability and performance of tokamak plasmas are limited by instabilities such as neoclassical tearing modes. This paper reports on an experimental proof of principle of a feedback control approach for real-time, autonomous suppression and stabilization of tearing modes in a tokamak. The system combines an electron cyclotron emission diagnostic for sensing of the tearing modes in the same sight line with a steerable electron cyclotron resonance heating and current drive (ECRH/ECCD) antenna. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/ECCD deposition location with the centre of the tearing mode are generated in real time and forwarded in closed loop to the steerable launcher and as a modulation pulse train to the gyrotron. Experimental results demonstrate the capability of the control system to track externally perturbed tearing modes in real time.

  19. Comparing Narrow- and Broad-line AGNs in a New Diagnostic Diagram for Emission-line Galaxies Based on WISE Data

    NASA Astrophysics Data System (ADS)

    Coziol, R.; Torres-Papaqui, J. P.; Andernach, H.

    2015-06-01

    Using a new color-color diagnostic diagram in the mid-infrared (MIR) built from WISE data, the MIRDD, we compare narrow-emission-line galaxies (NELGs) that exhibit different activity types (star-forming galaxies (SFGs) and active galactic nuclei (AGNs), i.e., LINERs, Seyfert 2 galaxies (Sy2s), and Transition-type Objects (TOs)), as determined using one standard diagnostic diagram in the optical (BPT-VO), with broad-line AGNs (QSOs and Sy1s) and BL Lac objects at low redshift (z≤slant 0.25). We show that the BL Lac objects occupy the same region as the LINERs in the MIRDD, whereas the QSOs and Sy1s occupy an intermediate region between the LINERs and the Sy2s. In the MIRDD these galaxies trace a sequence that can be reproduced by a power law, {{F}ν }={{ν }α }, where the spectral index, α, varies from 0 to -2, which is similar to what is observed in the optical/ultraviolet part of the spectra of AGNs with different luminosities. For the NELGs with different activity types, we perform a stellar-population synthesis analysis, confirming that their specific positions in the MIRD depend on their star formation histories (SFH) and demonstrating that the W2-W3 color is tightly correlated with the level of star formation in their host galaxies. In good agreement with the SFH analysis, a comparison of their MIR colors with the colors yielded by spectral energy distributions (SEDs) of galaxies with different activity types shows that the SED of the LINERs is similar to the SEDs of the QSOs and Sy1s, consistent with AGN galaxies with mild star formation, whereas the SEDs of the Sy2s and TOs are consistent with AGN galaxies with strong star formation components. For the BL Lac objects, we show that their blue MIR colors can only be fitted with an SED that has no star formation component, consistent with AGNs in elliptical-type galaxies. From their similarities in MIR colors and SEDs, we infer that, in the nearby universe, the level of star formation activity most probably

  20. Active galactic nuclei emission line diagnostics and the mass-metallicity relation up to redshift z ∼ 2: The impact of selection effects and evolution

    SciTech Connect

    Juneau, Stéphanie; Bournaud, Frédéric; Daddi, Emanuele; Elbaz, David; Duc, Pierre-Alain; Gobat, Raphael; Jean-Baptiste, Ingrid; Le Floc'h, Émeric; Pannella, Maurilio; Schreiber, Corentin; Trump, Jonathan R.; Dickinson, Mark

    2014-06-10

    Emission line diagnostic diagrams probing the ionization sources in galaxies, such as the Baldwin-Phillips-Terlevich (BPT) diagram, have been used extensively to distinguish active galactic nuclei (AGN) from purely star-forming galaxies. However, they remain poorly understood at higher redshifts. We shed light on this issue with an empirical approach based on a z ∼ 0 reference sample built from ∼300,000 Sloan Digital Sky Survey galaxies, from which we mimic selection effects due to typical emission line detection limits at higher redshift. We combine this low-redshift reference sample with a simple prescription for luminosity evolution of the global galaxy population to predict the loci of high-redshift galaxies on the BPT and Mass-Excitation (MEx) diagnostic diagrams. The predicted bivariate distributions agree remarkably well with direct observations of galaxies out to z ∼ 1.5, including the observed stellar mass-metallicity (MZ) relation evolution. As a result, we infer that high-redshift star-forming galaxies are consistent with having normal interstellar medium (ISM) properties out to z ∼ 1.5, after accounting for selection effects and line luminosity evolution. Namely, their optical line ratios and gas-phase metallicities are comparable to that of low-redshift galaxies with equivalent emission-line luminosities. In contrast, AGN narrow-line regions may show a shift toward lower metallicities at higher redshift. While a physical evolution of the ISM conditions is not ruled out for purely star-forming galaxies and may be more important starting at z ≳ 2, we find that reliably quantifying this evolution is hindered by selections effects. The recipes provided here may serve as a basis for future studies toward this goal. Code to predict the loci of galaxies on the BPT and MEx diagnostic diagrams and the MZ relation as a function of emission line luminosity limits is made publicly available.

  1. MID-INFRARED PROPERTIES OF THE SWIFT BURST ALERT TELESCOPE ACTIVE GALACTIC NUCLEI SAMPLE OF THE LOCAL UNIVERSE. I. EMISSION-LINE DIAGNOSTICS

    SciTech Connect

    Weaver, K. A.; Melendez, M.; Mushotzky, R. F.; Kraemer, S.; Engle, K.; Malumuth, E.; Tueller, J.; Markwardt, C.; Berghea, C. T.; Dudik, R. P.; Winter, L. M.; Armus, L.

    2010-06-20

    We compare mid-infrared emission-line properties from high-resolution Spitzer spectra of a hard X-ray (14-195 keV) selected sample of nearby (z < 0.05) active galactic nuclei (AGNs) detected by the Burst Alert Telescope (BAT) aboard Swift. The luminosity distribution for the mid-infrared emission lines, [O IV] 25.89 {mu}m, [Ne II] 12.81 {mu}m, [Ne III] 15.56 {mu}m, and [Ne V] 14.32/24.32 {mu}m, and hard X-ray continuum show no differences between Seyfert 1 and Seyfert 2 populations; however, six newly discovered BAT AGNs are under-luminous in [O IV], most likely the result of dust extinction in the host galaxy. The overall tightness of the mid-infrared correlations and BAT fluxes and luminosities suggests that the emission lines primarily arise in gas ionized by the AGNs. We also compare the mid-infrared emission lines in the BAT AGNs with those from published studies of ULIRGs, Palomar-Green quasars, star-forming galaxies, and LINERs. We find that the BAT AGN sample falls into a distinctive region when comparing the [Ne III]/[Ne II] and the [O IV]/[Ne III] ratios. These line ratios are lower in sources that have been previously classified in the mid-infrared/optical as AGNs than those found for the BAT AGNs, suggesting that, in our X-ray selected sample, the AGNs represent the main contribution to the observed line emission. These ratios represent a new emission line diagnostic for distinguishing between AGNs and star-forming galaxies.

  2. DIAGNOSTIC LINE EMISSION FROM EXTREME ULTRAVIOLET AND X-RAY-ILLUMINATED DISKS AND SHOCKS AROUND LOW-MASS STARS

    SciTech Connect

    Hollenbach, David; Gorti, U.

    2009-10-01

    Extreme ultraviolet (EUV; 13.6 eV diagnostic lines (e.g., [Ne II] 12.8 {mu}m and [O I] 6300 A) that we model as functions of key parameters such as EUV luminosity and spectral shape, X-ray luminosity and spectral shape, and wind mass loss rate and shock speed. Comparing our models with observations, we conclude that either internal shocks in the winds or X-rays incident on the disk surfaces often produce the observed [Ne II] line, although there are cases where EUV may dominate. Shocks created by the oblique interaction of winds with disks are unlikely [Ne II] sources because these shocks are too weak to ionize Ne. Even if [Ne II] is mainly produced by X-rays or internal wind shocks, the neon observations typically place upper limits of {approx}<10{sup 42} s{sup -1} on the EUV photon luminosity of these young low-mass stars. The observed [O I] 6300 A line has both a low velocity component (LVC) and a high velocity component. The latter likely arises in internal wind shocks. For the former we find that X-rays likely produce more [O I] luminosity than either the EUV layer, the transition layer between the EUV and X-ray layer, or the shear layer where the protostellar wind shocks and entrains disk material in a radial flow across the surface of the disk. Our soft X-ray models produce [O I] LVCs with luminosities up to 10{sup -4} L{sub sun}, but may not be able to explain the most luminous LVCs.

  3. CORONAL EMISSION LINES AS THERMOMETERS

    SciTech Connect

    Judge, Philip G.

    2010-01-10

    Coronal emission-line intensities are commonly used to measure electron temperatures using emission measure and/or line ratio methods. In the presence of systematic errors in atomic excitation calculations and data noise, the information on underlying temperature distributions is fundamentally limited. Increasing the number of emission lines used does not necessarily improve the ability to discriminate between different kinds of temperature distributions.

  4. PEARS Emission Line Galaxies

    NASA Technical Reports Server (NTRS)

    Pirzkal, Nor; Rothberg, Barry; Ly, Chun; Rhoads, James E.; Malhotra, Sangeeta; Grogin, Norman A.; Dahlen, Tomas; Meurer, Gerhardt R.; Walsh, Jeremy; Hathi, Nimish P.; Cohen, Seth; Belini, Andrea; Holwerda, Benne W.; Straughn, Amber; Mechtley, Matthew

    2012-01-01

    We present a full analysis of the Probing Evolution And Reionization Spectroscopically (PEARS) slitless grism spectroscopic data obtained vl'ith the Advanced Camera for Surveys on HST. PEARS covers fields within both the Great Observatories Origins Deep Survey (GOODS) North and South fields, making it ideal as a random surveY of galaxies, as well as the availability of a wide variety of ancillary observations to support the spectroscopic results. Using the PEARS data we are able to identify star forming galaxies within the redshift volume 0 < z < 1.5. Star forming regions in the PEARS survey are pinpointed independently of the host galaxy. This method allOW8 us to detect the presence of multiple emission line regions (ELRs) within a single galaxy. 1162 [OII], [OIII] and/or H-alpha emission lines have been identified in the PEARS sample of approx 906 galaxies down to a limiting flux of approx 10 - 18 erg/s/sq cm . The ELRs have also been compared to the properties of the host galaxy, including morphology, luminosity, and mass. From this analysis we find three key results: 1) The computed line luminosities show evidence of a flattening in the luminosity function with increasing redshift; 2) The star forming systems show evidence of disturbed morphologies, with star formation occurring predominantly within one effective (half-light) radius. However, the morphologies show no correlation with host stellar mass; and 3) The number density of star forming galaxies with M(*) >= 10(exp 9) Solar M decreases by an order of magnitude at z<=0.5 relative to the number at 0.5 < z < 0.9 in support of the argument for galaxy downsizing.

  5. Spectral Line Shapes as a Diagnostic Tool in Magnetic Fusion

    SciTech Connect

    Stamm, R; Capes, H; Demura, A; Godbert-Mouret, L; Koubiti, M; Marandet, Y; Mattioli, M; Rosato, J; Rosmej, F; Fournier, K B

    2006-07-22

    Spectral line shapes and intensities are used for obtaining information on the various regions of magnetic fusion devices. Emission from low principal quantum numbers of hydrogen isotopes is analyzed for understanding the complex recycling mechanism. Lines emitted from high principal quantum numbers of hydrogen and helium are dominated by Stark effect, allowing an electronic density diagnostic in the divertor. Intensities of lines emitted by impurities are fitted for a better knowledge of ion transport in the confined plasma.

  6. Spectral classification of emission-line galaxies

    NASA Astrophysics Data System (ADS)

    Dessauges-Zavadsky, M.; Pindao, M.; Maeder, A.; Kunth, D.

    2000-03-01

    The main goal of this work is to further investigate the classification of emission-line galaxies from the ``Spectrophotometric Catalogue of H II galaxies'' by Terlevich et al. (1991) in a homogeneous and objective way, using the three line-ratio diagrams, called diagnostic diagrams, of Veilleux & Osterbrock (1987). On the basis of the resulting catalogue, we critically discuss the classification methods in the optical range. In particular we compare our classification scheme to the one done by Rola et al. (1997) which is efficient for the classification of redshifted galaxies. We also propose a new diagnostic diagram involving the known intensity ratio R23=([O II],l 3727+[O III] l 4959+{[O III] l 5007)/Hb which appears to be a very good criterion allowing to discriminate the Seyfert 2 from H ii galaxies. The revised catalogue including 314 narrow-emission-line galaxies contains H II galaxies, Seyfert 2 galaxies, Low Ionization Nuclear Emission-Line Regions (hereafter LINERs) galaxies and some particular types of galaxies with the most intriguing ones, called ``ambiguous'', due to the ambiguity of their location in the diagnostic diagrams. These galaxies appear as H II galaxies and as active galactic nuclei (hereafter AGNs) in different diagrams of Veilleux & Osterbrock and constitute certainly a sample of particularly interesting candidates for a thorough study of connections between starbursts and AGNs. Available in electronic form only via anonymous ftp 130.79.128.5 or http://cdsweb.u-strasbg.fr/Abstract.html

  7. Detection of [O I] λ6300 and Other Diagnostic Emission Lines in the Diffuse Ionized Gas of M33 with Gemini-North

    NASA Astrophysics Data System (ADS)

    Voges, E. S.; Walterbos, R. A. M.

    2006-06-01

    We present spectroscopic observations of diffuse ionized gas (DIG) in M33 near the H II region NGC 604. We present the first detection of [O I] λ6300 in the DIG of M33, one of the critical lines for distinguishing photoionization from shock ionization models. We measure [O I]/Hα in the range of 0.04-0.10 and an increase in this ratio with decreasing emission measure. Our measurements of [S II]/Hα and [N II]/Hα also rise with decreasing emission measure, while our [O III]/Hβ measurements remain fairly constant. We have one tentative detection of He I in the region of brightest emission measure, with a ratio of He I/Hα = 0.033 +/- 0.019, indicating that the helium is at least partially ionized. We compare our observed emission-line ratios to photoionization models and find that field star ionization models do not fit our data well. Leaky H II region models are consistent with our data, without the need to invoke additional ionization mechanisms to fit our [O I] or [O III] measurements. The closest large H II region is NGC 604 and is therefore a likely candidate for the source of the ionizing photons for the gas in this region.

  8. Coronal Diagnostics from Cometary Emission

    NASA Astrophysics Data System (ADS)

    Bryans, Paul; Pesnell, William D; Seaton, Daniel B; West, Matthew J

    2014-06-01

    The extreme ultraviolet (EUV) emission observed from sungrazing comets as they pass through the solar atmosphere can be used to infer the properties of the corona. In this paper we will discuss several of these properties that can be estimated from the EUV observations of Comet Lovejoy from AIA/SDO and SWAP/PROBA2. The longevity of the emission allows us to constrain the coronal electron density through which the comet passes. We will also discuss how dispersion of the emitting cometary material we can be used to estimate the local Alfven speed in the corona. Finally, measuring the deformation of the magnetic field as it is impacted by the comet can be used to estimate the magnetic field strength in this location. In the absence of the comet, none of these parameters are directly measurable in the corona. Sungrazing comets are thus unique probes of the solar atmosphere.

  9. MODELING MOLECULAR HYPERFINE LINE EMISSION

    SciTech Connect

    Keto, Eric; Rybicki, George

    2010-06-20

    In this paper, we discuss two approximate methods previously suggested for modeling hyperfine spectral line emission for molecules whose collisional transition rates between hyperfine levels are unknown. Hyperfine structure is seen in the rotational spectra of many commonly observed molecules such as HCN, HNC, NH{sub 3}, N{sub 2}H{sup +}, and C{sup 17}O. The intensities of these spectral lines can be modeled by numerical techniques such as {Lambda}-iteration that alternately solve the equations of statistical equilibrium and the equation of radiative transfer. However, these calculations require knowledge of both the radiative and collisional rates for all transitions. For most commonly observed radio frequency spectral lines, only the net collisional rates between rotational levels are known. For such cases, two approximate methods have been suggested. The first method, hyperfine statistical equilibrium, distributes the hyperfine level populations according to their statistical weight, but allows the population of the rotational states to depart from local thermal equilibrium (LTE). The second method, the proportional method, approximates the collision rates between the hyperfine levels as fractions of the net rotational rates apportioned according to the statistical degeneracy of the final hyperfine levels. The second method is able to model non-LTE hyperfine emission. We compare simulations of N{sub 2}H{sup +} hyperfine lines made with approximate and more exact rates and find that satisfactory results are obtained.

  10. Exhaust emission control and diagnostics

    DOEpatents

    Mazur, Christopher John; Upadhyay, Devesh

    2006-11-14

    A diesel engine emission control system uses an upstream oxidation catalyst and a downstream SCR catalyst to reduce NOx in a lean exhaust gas environment. The engine and upstream oxidation catalyst are configured to provide approximately a 1:1 ratio of NO to NO2 entering the downstream catalyst. In this way, the downstream catalyst is insensitive to sulfur contamination, and also has improved overall catalyst NOx conversion efficiency. Degradation of the system is determined when the ratio provided is no longer near the desired 1:1 ratio. This condition is detected using measurements of engine operating conditions such as from a NOx sensor located downstream of the catalysts. Finally, control action to adjust an injected amount of reductant in the exhaust gas based on the actual NO to NO2 ratio upstream of the SCR catalyst and downstream of the oxidation catalyst.

  11. Diagnostic of the self-healing of metallized polypropylene film by modeling of the broadening emission lines of aluminum emitted by plasma discharge

    SciTech Connect

    Tortai, J.-H.; Bonifaci, N.; Denat, A.; Trassy, C.

    2005-03-01

    Metallized-film capacitors have the property, even under high continuous voltage, to self-heal i.e., to clear a defect in the dielectric. The self-healing process is a consequence of a transient arc discharge. It has been previously shown that during the discharge, due to Joule effect, the metal is vaporized until the arc extinguishes. The discharge duration has been found to be inversely proportional to the mechanical pressure applied on the layers of metallized films making up a capacitor. The aim of this study is to understand the physical processes involved in this spontaneous extinction of the arc discharge. Emission spectroscopy has been used to provide information about the physical properties (temperatures, electronic and neutral particles densities, etc.) of the plasma induces by a self-healing. An analysis, based on the broadenings and shifts of Al atomic lines, of the experimental light spectra obtained has shown that the self-healing process leads to the generation, from the vaporized metal, of a high-density and relatively weakly ionized aluminum plasma. The plasma density increases with the pressure applied on the film layers and, consequently, the density power needed to extend the plasma zone increases as well and the arc discharge goes out faster as experimentally observed.

  12. The Far Infrared Lines of OH as Molecular Cloud Diagnostics

    NASA Astrophysics Data System (ADS)

    Smith, Howard A.; Ashby, Matt; Fischer, Jackie; Gonzales, Eduardo; Spinoglio, Luigi; Dudley, Chris

    There are 15 far-IR lines arising between the lowest eight rotational levels of OH and ISO detected nine of them. Furthermore ISO found the OH lines sometimes in emission and sometimes in absorption in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. This set of OH lines provides a uniquely valuable diagnostic for many reasons: the lines span a wide wavelength range (28.9μm to 163.2μm); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and not least the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters and the large optical depths of the strongest lines make modeling the full set a difficult job. We have used a modified SWAS montecarlo radiative transfer code to analyze the ISO/LWS spectra of a number of objects including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum.

  13. 40 CFR 1033.112 - Emission diagnostics for SCR systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Emission diagnostics for SCR systems. 1033.112 Section 1033.112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Emission Standards and Related Requirements § 1033.112 Emission diagnostics for SCR...

  14. 40 CFR 1033.112 - Emission diagnostics for SCR systems.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Emission diagnostics for SCR systems. 1033.112 Section 1033.112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Emission Standards and Related Requirements § 1033.112 Emission diagnostics for SCR...

  15. The Far Infrared Lines of OH as Molecular Cloud Diagnostics

    NASA Technical Reports Server (NTRS)

    Smith, Howard A.

    2004-01-01

    Future IR missions should give some priority to high resolution spectroscopic observations of the set of far-IR transitions of OH. There are 15 far-IR lines arising between the lowest eight rotational levels of OH, and ISO detected nine of them. Furthermore, ISO found the OH lines, sometimes in emission and sometimes in absorption, in a wide variety of galactic and extragalactic objects ranging from AGB stars to molecular clouds to active galactic nuclei and ultra-luminous IR galaxies. The ISO/LWS Fabry-Perot resolved the 119 m doublet line in a few of the strong sources. This set of OH lines provides a uniquely important diagnostic for many reasons: the lines span a wide wavelength range (28.9 m to 163.2 m); the transitions have fast radiative rates; the abundance of the species is relatively high; the IR continuum plays an important role as a pump; the contribution from shocks is relatively minor; and, not least, the powerful centimeter-wave radiation from OH allows comparison with radio and VLBI datasets. The problem is that the large number of sensitive free parameters, and the large optical depths of the strongest lines, make modeling the full set a difficult job. The SWAS montecarlo radiative transfer code has been used to analyze the ISO/LWS spectra of a number of objects with good success, including in both the lines and the FIR continuum; the DUSTY radiative transfer code was used to insure a self-consistent continuum. Other far IR lines including those from H2O, CO, and [OI] are also in the code. The OH lines all show features which future FIR spectrometers should be able to resolve, and which will enable further refinements in the details of each cloud's structure. Some examples are given, including the case of S140, for which independent SWAS data found evidence for bulk flows.

  16. Electron cyclotron emission diagnostics on KSTAR tokamak

    SciTech Connect

    Jeong, S. H.; Lee, K. D.; Kwon, M.; Kogi, Y.; Kawahata, K.; Nagayama, Y.; Mase, A.

    2010-10-15

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration.

  17. Electron cyclotron emission diagnostics on KSTAR tokamak.

    PubMed

    Jeong, S H; Lee, K D; Kogi, Y; Kawahata, K; Nagayama, Y; Mase, A; Kwon, M

    2010-10-01

    A new electron cyclotron emission (ECE) diagnostics system was installed for the Second Korea Superconducting Tokamak Advanced Research (KSTAR) campaign. The new ECE system consists of an ECE collecting optics system, an overmode circular corrugated waveguide system, and 48 channel heterodyne radiometer with the frequency range of 110-162 GHz. During the 2 T operation of the KSTAR tokamak, the electron temperatures as well as its radial profiles at the high field side were measured and sawtooth phenomena were also observed. We also discuss the effect of a window on in situ calibration. PMID:21033954

  18. BXO mode-converted electron Bernstein emission diagnostic (invited)

    NASA Astrophysics Data System (ADS)

    Volpe, F.; Laqua, H. P.

    2003-03-01

    Electron temperature profiles at densities above the electron cyclotron emission (ECE) cutoff are measured at the W7-AS stellarator by a novel diagnostic based on black body emission and Bernstein-extraordinary-ordinary mode conversion of electron Bernstein waves (EBWs). The radiation is collected along a special oblique line of sight by an antenna with gaussian optics. This was optimized for maximal conversion efficiency and minimal Doppler broadening by means of EBW ray tracing calculations in full stellarator geometry. The elliptical O-mode polarization detected along the oblique line of sight is changed into a linear polarization by a broadband quarter wave shifter, namely an elliptical waveguide. The signal is spectrum analyzed by an heterodyne radiometer and temperature profiles are derived from spectra by means of ray tracing. The diagnostic was applied to measurements of edge-localized modes to illustrate its advantages in terms of spatial and temporal resolution. Moreover, for the first time, the heat wave propagation method for the determination of local heat transport coefficients was extended beyond the ECE cutoff density by combining EBW emission measurements at the first harmonic (f=66-78 GHz) with modulated EBW heating at the second harmonic (140 GHz).

  19. The Diagnostic Potential of Fe Lines Applied to Protostellar Jets

    NASA Astrophysics Data System (ADS)

    Giannini, T.; Nisini, B.; Antoniucci, S.; Alcalá, J. M.; Bacciotti, F.; Bonito, R.; Podio, L.; Stelzer, B.; Whelan, E. T.

    2013-11-01

    We investigate the diagnostic capabilities of iron lines for tracing the physical conditions of shock-excited gas in jets driven by pre-main sequence stars. We have analyzed the 3000-25000 Å, X-shooter spectra of two jets driven by the pre-main sequence stars ESO-Hα 574 and Par-Lup 3-4. Both spectra are very rich in [Fe II] lines over the whole spectral range; in addition, lines from [Fe III] are detected in the ESO-Hα 574 spectrum. Non-local thermal equilibrium codes solving the equations of the statistical equilibrium along with codes for the ionization equilibrium are used to derive the gas excitation conditions of electron temperature and density and fractional ionization. An estimate of the iron gas-phase abundance is provided by comparing the iron lines emissivity with that of neutral oxygen at 6300 Å. The [Fe II] line analysis indicates that the jet driven by ESO-Hα 574 is, on average, colder (T e ~ 9000 K), less dense (n e ~ 2 × 104 cm-3), and more ionized (x e ~ 0.7) than the Par-Lup 3-4 jet (T e ~ 13,000 K, n e ~ 6 × 104 cm-3, x e < 0.4), even if the existence of a higher density component (n e ~ 2 × 105 cm-3) is probed by the [Fe III] and [Fe II] ultra-violet lines. The physical conditions derived from the iron lines are compared with shock models suggesting that the shock at work in ESO-Hα 574 is faster and likely more energetic than the Par-Lup 3-4 shock. This latter feature is confirmed by the high percentage of gas-phase iron measured in ESO-Hα 574 (50%-60% of its solar abundance in comparison with less than 30% in Par-Lup 3-4), which testifies that the ESO-Hα 574 shock is powerful enough to partially destroy the dust present inside the jet. This work demonstrates that a multiline Fe analysis can be effectively used to probe the excitation and ionization conditions of the gas in a jet without any assumption on ionic abundances. The main limitation on the diagnostics resides in the large uncertainties of the atomic data, which, however, can

  20. Observations of emission lines in M supergiants

    NASA Technical Reports Server (NTRS)

    Lambert, D. L.

    1979-01-01

    Copernicus observations of Mg 2 h and k emission lines from M giants and supergiants are described. Supergiants with extensive circumstellar gas shells show an asymmetric k line. The asymmetry is ascribed to superimposed lines of Fe 1 and Mn 1. The Mg 2 line width fit the Wilson-Bappu relation derived from observations of G and K Stars. Results of correlated ground-based observations include (1) the discovery of K 1 fluorescent emission from the Betelgeuse shell; (2) extimates of the mass-loss rates; and (3) the proposal that silicate dust grains must account for the major fraction of the Si atoms in the Betelgeuse shell.

  1. Fe L-Shell Emission Lines at 7 - 9 Angstroms

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Beiersdorfer, Peter; Brown, Greg; Behar, Edhud

    Fe L-shell emission lines at wavelengths less than 10 angstroms come from n to 2 (n = 4 5 6..) transitions. These lines embed information such as electron density and/or temperature that is of fundamental importance to understanding the physics of astrophysical objects. Unresolved by previous x-ray observatories these low wavelength Fe lines are clearly observable by Chandra and XMM x-ray satellites. To meet the needs of using these lines as diagnostics we have studied the n to 2 transitions (n = 4 5 6..) Fe L-shell lines using the LLNL electron beam ion trap following our Fe L-shell emission line measurements for the 3-2 transitions (Brown et al APJ supp. 2002). Our measurement and its comparison with code simulations will be reported together with a discussion of the possible use of these lines as diagnostics for astrophysics. This work was performed under the auspices of the U.S. DOE by LLNL under contract No. W-7405-Eng-48 and supported by NASA SARA grants to LLNL GSFC and Columbia University.

  2. 40 CFR 1033.110 - Emission diagnostics-general requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Emission diagnostics-general requirements. 1033.110 Section 1033.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Emission Standards and Related Requirements § 1033.110 Emission...

  3. 40 CFR 1033.110 - Emission diagnostics-general requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Emission diagnostics-general requirements. 1033.110 Section 1033.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Emission Standards and Related Requirements § 1033.110 Emission...

  4. 40 CFR 1033.110 - Emission diagnostics-general requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Emission diagnostics-general requirements. 1033.110 Section 1033.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Emission Standards and Related Requirements § 1033.110 Emission...

  5. PROFIT: Emission-line PROfile FITting routine

    NASA Astrophysics Data System (ADS)

    Riffel, Rogemar A.

    2012-04-01

    The PROFIT is an IDL routine to do automated fitting of emission-line profiles by Gaussian curves or Gauss-Hermite series otimized for use in Integral Field and Fabry-Perot data cubes. As output PROFIT gives two-dimensional FITS files for the emission-line flux distribution, centroid velocity, velocity dispersion and higher order Gauss-Hermite moments (h3 and h4).

  6. 40 CFR 1033.112 - Emission diagnostics for SCR systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Emission diagnostics for SCR systems....112 Emission diagnostics for SCR systems. Engines equipped with SCR systems using separate reductant.... This section does not apply for SCR systems using the engine's fuel as the reductant. (a)...

  7. Local Group Galaxy Emission-line Survey

    NASA Astrophysics Data System (ADS)

    Blaha, Cindy; Baildon, Taylor; Mehta, Shail; Garcia, Edgar; Massey, Philip; Hodge, Paul W.

    2015-01-01

    We present the results of the Local Group Galaxy Emission-line Survey of Hα emission regions in M31, M33 and seven dwarf galaxies in (NGC6822, IC10, WLM, Sextans A and B, Phoenix and Pegasus). Using data from the Local Group Galaxy Survey (LGGS - see Massey et al, 2006), we used continuum-subtracted Ha emission line images to define emission regions with a faint flux limit of 10 -17 ergs-sec-1-cm-2above the background. We have obtained photometric measurements for roughly 7450 Hα emission regions in M31, M33 and five of the seven dwarf galaxies (no regions for Phoenix or Pegasus). Using these regions, with boundaries defined by Hα-emission flux limits, we also measured fluxes for the continuum-subtracted [OIII] and [SII] images and constructed a catalog of Hα fluxes, region sizes and [OIII]/ Hα and [SII]/ Hα line ratios. The HII region luminosity functions and size distributions for the spiral galaxies M31 and M33 are compared with those of the dwarf galaxies NGC 6822 and IC10. For M31 and M33, the average [SII]/ Hα and [OIII]/ Hα line ratios, plotted as a function of galactocentric radius, display a linear trend with shallow slopes consistent with other studies of metallicity gradients in these galaxies. The galaxy-wide averages of [SII]/ Hα line ratios correlate with the masses of the dwarf galaxies following the previously established dwarf galaxy mass-metallicity relationship. The slope of the luminosity functions for the dwarf galaxies varies with galaxy mass. The Carleton Catalog of this Local Group Emission-line Survey will be made available on-line.

  8. Theoretical quasar emission-line ratios. V - Balmer continuum emission

    NASA Technical Reports Server (NTRS)

    Puetter, R. C.; Levan, P. D.

    1982-01-01

    Isothermal, isobaric models of quasar emission line regions are presented which include an improved treatment of radiative transfer in the bound-free continua, based on a generalization of frequency-integrated line transfer techniques and on the use of a probabilistic radiative transfer equation which explicitly distinguishes between the flux divergence coefficient and the photon escape probability. It is found that Balmer continuum emission can be obtained without compromising observed line ratios. It is also established that optically thin or thick Balmer continuum emission models with blended Fe II line are consistent with 4000-2000 A 'blue bump' observations, and that the improved radiative transfer treatment makes order-of-magnitude corrections to level populations and local cooling rates calculated with past techniques.

  9. Emission Lines and the High Energy Continuum

    NASA Technical Reports Server (NTRS)

    Green, Paul

    1998-01-01

    Quasars show many striking relationships between line and continuum radiation whose origins remain a mystery. FeII, [OIII], Hbeta, and HeII emission line properties correlate with high energy continuum properties such as the relative strength of X-ray emission, and X-ray continuum slope. At the same time, the shape of the high energy continuum may vary with luminosity. An important tool for studying global properties of Quasi Stellar Objects (QSOs) is the co-addition of data for samples of QSOS. We use this to show that X-ray bright (XB) QSOs show stronger emission lines in general, but particularly from the narrow line region. The difference in the [OIII]/Hbeta ratio is particularly striking, and even more so when blended FeII emission is properly subtracted. Weaker narrow forbidden lines ([OII] and NeV) are enhanced by factors of 2 to 3 in both UV and optical XB composite spectra. The physical origin of these diverse and interrelated correlations has yet to be determined. Unfortunately, many physically informative trends intrinsic to QSOs may be masked by dispersion in the data due to either low signal-to-noise or variability. An important tool for studying global properties of QSOs is the co-addition of data for samples of QSOS. We use this to show that X-ray bright (XB) QSOs show stronger emission lines in general, but particularly from the narrow line region. The difference in the [OIII]/Hbeta ratio is particularly striking, and even more so when blended Fell emission is properly subtracted. Weaker narrow forbidden lines ([OII] and NeV) are enhanced by factors of 2 to 3 in both UV and optical XB composite spectra. We describe a large-scale effort now underway to probe these effects in large samples, using both data and analysis as homogeneous as possible. Using an HST FOS Atlas of QSO spectra, with primary comparison to ROSAT PSPC spectral constraints, we will model the Big Blue Bump, its relationship to luminosity and QSO type, and we will analyze and

  10. Investigating Starburst Galaxy Emission Line Equivalent Widths

    NASA Astrophysics Data System (ADS)

    Meskhidze, Helen; Richardson, Chris T.

    2016-01-01

    Modeling star forming galaxies with spectral synthesis codes allows us to study the gas conditions and excitation mechanisms that are necessary to reproduce high ionization emission lines in both local and high-z galaxies. Our study uses the locally optimally-emitting clouds model to develop an atlas of starburst galaxy emission line equivalent widths. Specifically, we address the following question: What physical conditions are necessary to produce strong high ionization emission lines assuming photoionization via starlight? Here we present the results of our photoionization simulations: an atlas spanning 15 orders of magnitude in ionizing flux and 10 orders of magnitude in hydrogen density that tracks over 150 emission lines ranging from the UV to the near IR. Each simulation grid contains ~1.5x104 photoionization models calculated by supplying a spectral energy distribution, grain content, and chemical abundances. Specifically, we will be discussing the effects on the emission line equivalent widths of varying the metallicity of the cloud, Z = 0.2 Z⊙ to Z = 5.0 Z⊙, and varying the star-formation history, using the instantaneous and continuous evolution tracks and the newly released Starburst99 Geneva rotation tracks.

  11. Infrared [Fe II] Emission Lines from Radiative Atomic Shocks

    NASA Astrophysics Data System (ADS)

    Koo, Bon-Chul; Raymond, John C.; Kim, Hyun-Jeong

    2016-06-01

    [Fe II] emission lines are prominent in the infrared (IR) and important as diagnostic tools for radiative atomic shocks. We investigate the emission characteristics of [Fe II] lines using a shock code developed by te{raymond1979} with updated atomic parameters. We first review general characteristics of the IR [Fe II] emission lines from shocked gas, and derive their fluxes as a function of shock speed and ambient density. We have compiled available IR [Fe II] line observations of interstellar shocks and compare them to the ratios predicted from our model. The sample includes both young and old supernova remnants in the Galaxy and the Large Magellanic Cloud and several Herbig-Haro objects. We find that the observed ratios of the IR [Fe II] lines generally fall on our grid of shock models, but the ratios of some mid-IR lines, e.g., fethreefive/fetwofive, fefive/fetwofive, and fefive/feoneseven, are significantly offset from our model grid. We discuss possible explanations and conclude that while uncertainties in the shock modeling and the observations certainly exist, the uncertainty in atomic rates appears to be the major source of discrepancy.

  12. Discovery of Polarized Line Emission in SN 1006

    NASA Astrophysics Data System (ADS)

    Sparks, W. B.; Pringle, J. E.; Carswell, R. F.; Long, K. S.; Cracraft, M.

    2015-12-01

    Laming predicted that the narrow Balmer line core of the ∼3000 km s‑1 shock in the SN 1006 remnant would be significantly polarized due to electron and proton impact polarization. Here, based on deep spectrally resolved polarimetry obtained with the European Southern Observatory (ESO)’s Very Large Telescope (VLT), we report the discovery of polarized line emission with a polarization degree of 1.3% and position angle orthogonal to the SNR filament. Correcting for an unpolarized broad line component, the implied narrow line polarization is ≈2.0%, close to the predictions of Laming. The predicted polarization is primarily sensitive to shock velocity and post-shock temperature equilibration. By measuring polarization for the SN 1006 remnant, we validate and enable a new diagnostic that has important applications in a wide variety of astrophysical situations, such as shocks, intense radiation fields, high energy particle streams, and conductive interfaces.

  13. Bright emission lines in new Seyfert galaxies

    SciTech Connect

    Afanasev, V.L.; Denisiuk, E.K.; Lipovetskii, V.A.; Shapovalova, A.I.

    1983-01-01

    Observational data are given on bright emission lines (H-alpha, H-beta, and forbidden N II, S II, and O III) for 14 recently discovered Seyfert galaxies. The investigated objects can be divided into three groups, which correspond approximately to the first (5 objects), the intermediate (4 objects), and the second (4 objects) Seyfert types. Attention is drawn to the properties of the galaxy Markaryan 1018, which has features of both the first and the second type and is distinguished by the weakness of its emission lines, which is probably due to a gas deficit. 7 references.

  14. Emission lines from hot astrophysical plasmas

    NASA Astrophysics Data System (ADS)

    Raymond, John C.

    The spectral lines which dominate the X-ray emission of hot, optically thin astrophysical plasmas reflect the elemental abundances, temperature distribution, and other physical parameters of the emitting gas. The accuracy and level of detail with which these parameters can be inferred are limited by the measurement uncertainties and uncertainties in atomic rates used to compute the model spectrum. This paper discusses the relative importance and the likely uncertainties in the various atomic rates and the likely uncertainties in the overall ionization balance and spectral line emissivities predicted by the computer codes currently used to fit X-ray spectral data.

  15. Molecular Hydrogen Line Emission from Photodissociation Regions

    NASA Astrophysics Data System (ADS)

    Chrysostomou, Antonio

    1993-01-01

    radiatively rather than by shocks. The diagnostic line ratio of the H2 v = 1-0 S(1) and 2-1 S(1) transitions is approximately 3 over the region observed implying that the lower levels of the molecule are slightly thermalised by the warm gas. The constancy of the ratio further implies that the collisional deexcitation rate must be constant along this region. This may be taken to mean that the physical conditions do not change along the region and that we are observing the surface of the PDR. The profile of the molecular emission along the slit can be successfully modelled if it is assumed that the large scale surface geometry in the region can be described by a parabola. The ortho to para ratio of H2, measured in the three PDR sources (M17 northern bar, NGC 2023 and Hubble 12), is less than the expected value for a hot (~300 K) gas in thermodynamic equilibrium (ie. 3). The measured values fall in the range 1.3 - 2.3. Modelling the orth to para ratio using the rates of spin conversion of the H2 molecule do not satisfy the observations. Some other form of processing the ortho to para ratio must be occuring and three different models are considered. First, a different reformation mechanism is considered which allows the newly formed molecule to reside on the surface of the grain for a certain amount of time before it evaporates into the gas. The second model describes a dynamic PDR. Hot gas at the surface of the PDR is allowed to escape setting up an advancing photodissociation front. If the front advances into the cooler gas before there is enough time for spin changing interactions to take place, then the measured ortho to para ratios will have values characteristic of the cooler (T ~ 50 - 150 K) gas. Both of these models can successfully reproduce the observed ortho to para ratios. The third model assumes that there is some processing of the ortho to para ratio during the fluorescent cascade, after it has been excited by ultraviolet photons. This model is not successful at

  16. Integration of On-Line and Off-Line Diagnostic Algorithms for Aircraft Engine Health Management

    NASA Technical Reports Server (NTRS)

    Kobayashi, Takahisa; Simon, Donald L.

    2007-01-01

    This paper investigates the integration of on-line and off-line diagnostic algorithms for aircraft gas turbine engines. The on-line diagnostic algorithm is designed for in-flight fault detection. It continuously monitors engine outputs for anomalous signatures induced by faults. The off-line diagnostic algorithm is designed to track engine health degradation over the lifetime of an engine. It estimates engine health degradation periodically over the course of the engine s life. The estimate generated by the off-line algorithm is used to update the on-line algorithm. Through this integration, the on-line algorithm becomes aware of engine health degradation, and its effectiveness to detect faults can be maintained while the engine continues to degrade. The benefit of this integration is investigated in a simulation environment using a nonlinear engine model.

  17. Extreme Ultraviolet Emission Lines of Iron Fe XI-XIII

    NASA Astrophysics Data System (ADS)

    Lepson, Jaan; Beiersdorfer, P.; Brown, G. V.; Liedahl, D. A.; Brickhouse, N. S.; Dupree, A. K.

    2013-04-01

    The extreme ultraviolet (EUV) spectral region (ca. 20--300 Å) is rich in emission lines from low- to mid-Z ions, particularly from the middle charge states of iron. Many of these emission lines are important diagnostics for astrophysical plasmas, providing information on properties such as elemental abundance, temperature, density, and even magnetic field strength. In recent years, strides have been made to understand the complexity of the atomic levels of the ions that emit the lines that contribute to the richness of the EUV region. Laboratory measurements have been made to verify and benchmark the lines. Here, we present laboratory measurements of Fe XI, Fe XII, and Fe XIII between 40-140 Å. The measurements were made at the Lawrence Livermore electron beam ion trap (EBIT) facility, which has been optimized for laboratory astrophysics, and which allows us to select specific charge states of iron to help line identification. We also present new calculations by the Hebrew University - Lawrence Livermore Atomic Code (HULLAC), which we also utilized for line identification. We found that HULLAC does a creditable job of reproducing the forest of lines we observed in the EBIT spectra, although line positions are in need of adjustment, and line intensities often differed from those observed. We identify or confirm a number of new lines for these charge states. This work was supported by the NASA Solar and Heliospheric Program under Contract NNH10AN31I and the DOE General Plasma Science program. Work was performed in part under the auspices of the Department of Energy by Lawrence Livermore National Laboratory under Contract DEAC52-07NA27344.

  18. Vaccum and beam diagnostic controls for ORIC beam lines

    SciTech Connect

    Tatum, B.A.

    1991-01-01

    Vacuum and beam diagnostic equipment on beam lines from the Oak Ridge Isochronous Cyclotron, ORIC, is now controlled by a new dedicated system. The new system is based on an industrial programmable logic controller with an IBM AT personal computer providing control room operator interface. Expansion of this system requires minimal reconfiguration and programming, thus facilitating the construction of additional beam lines. Details of the implementation, operation, and performance of the system are discussed. 2 refs., 2 figs.

  19. MG II h&k line diagnostics of IM Pegasi

    NASA Astrophysics Data System (ADS)

    Olah, K.; Marik, D.; Houdebine, E. R.; Dempsey, R. C.; Budding, E.

    1998-02-01

    We have analysed the Mgii h&k resonance lines of IM Peg (KII-III) on 14 high resolution IUE LWR spectra and compared the results coming from visual spectroscopic and UBV(RI)_C photometric data. The `clean' spectra (free from interstellar absorption) were modelled using a convolution of the rotational profile with a Gaussian profile, that represents macroturbulence and broadenings of other origin, the former dominating. Significant variations in the h&k line fluxes and widths were found throughout the orbital phase range. A line broadening effect is found at maximum spot visibility both in the k and h lines. The Mgii line widths increase linearly with the flux of the transition region lines as a function of rotational phase. Anticorrelations as a function of phase were found between the Mgii line fluxes and the higher temperature lines. The k line is broader than the h line, correlated with a slope greater than unity, in keeping with a greater radiation transfer effect in the k line, and a non-optically thin medium at all phases. We observe a systematic asymmetry in the ratio of the h to k line profiles at all phases. The spectral diagnostics thus suggest the appearance of a plage region on the stellar disc. We obtained new orbital elements of the IM Peg system, deriving a small, but non-zero eccentricity. The authors would like to dedicate this paper to their late referee, Dr. P.B. Byrne.

  20. The emission line - continuum connection in galaxies

    NASA Astrophysics Data System (ADS)

    Sodre, Laerte; Albernaz-Sirico, Ana Carolina

    2015-08-01

    Star-forming galaxies with a blue continuum tend to present prominent emission lines, whereas in red galaxies emission lines are associated mostly to nuclear activity or to certain stellar populations, like post-AGB stars. In this work we have used tools of machine learning to investigate how theemission line equivalent widths of galaxies are related to their optical continuum. From the analysis of a sample of high S/N spectra of SDSS/DR9 we show that indeed it is possible to estimate with good accuracy the equivalent width of the most intense emission lines from galaxy continuum information only for star-forming galaxies and AGNs (LINERS and Seyfer 2 emitters) by using simple relationships (linear and/or polynomial models) between the EWs and the relative flux at certain wavelengths. An important motivation for this work is to produce realistic spectra to test the data reduction pipelines of the new generation of galaxy surveys, like J-PAS and PFS/SuMIRe.

  1. Galaxy emission line classification using three-dimensional line ratio diagrams

    SciTech Connect

    Vogt, Frédéric P. A.; Dopita, Michael A.; Kewley, Lisa J.; Sutherland, Ralph S.; Scharwächter, Julia; Basurah, Hassan M.; Ali, Alaa; Amer, Morsi A.

    2014-10-01

    Two-dimensional (2D) line ratio diagnostic diagrams have become a key tool in understanding the excitation mechanisms of galaxies. The curves used to separate the different regions—H II-like or excited by an active galactic nucleus (AGN)—have been refined over time but the core technique has not evolved significantly. However, the classification of galaxies based on their emission line ratios really is a multi-dimensional problem. Here we exploit recent software developments to explore the potential of three-dimensional (3D) line ratio diagnostic diagrams. We introduce the ZQE diagrams, which are a specific set of 3D diagrams that separate the oxygen abundance and the ionization parameter of H II region-like spectra and also enable us to probe the excitation mechanism of the gas. By examining these new 3D spaces interactively, we define the ZE diagnostics, a new set of 2D diagnostics that can provide the metallicity of objects excited by hot young stars and that cleanly separate H II region-like objects from the different classes of AGNs. We show that these ZE diagnostics are consistent with the key log [N II]/Hα versus log [O III]/Hβ diagnostic currently used by the community. They also have the advantage of attaching a probability that a given object belongs to one class or the other. Finally, we discuss briefly why ZQE diagrams can provide a new way to differentiate and study the different classes of AGNs in anticipation of a dedicated follow-up study.

  2. SOLAR TRANSITION REGION LINES OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH: DIAGNOSTICS FOR THE O IV AND Si IV LINES

    SciTech Connect

    Dudík, J.; Del Zanna, G.; Mason, H. E.; Dzifčáková, E.; Golub, L.

    2014-01-01

    The formation of the transition region O IV and Si IV lines observable by the Interface Region Imaging Spectrograph (IRIS) is investigated for both Maxwellian and non-Maxwellian conditions characterized by a κ-distribution exhibiting a high-energy tail. The Si IV lines are formed at lower temperatures than the O IV lines for all κ. In non-Maxwellian situations with lower κ, the contribution functions are shifted to lower temperatures. Combined with the slope of the differential emission measure, it is possible for the Si IV lines to be formed at very different regions of the solar transition region than the O IV lines; possibly close to the solar chromosphere. Such situations might be discernible by IRIS. It is found that photoexcitation can be important for the Si IV lines, but is negligible for the O IV lines. The usefulness of the O IV ratios for density diagnostics independently of κ is investigated and it is found that the O IV 1404.78 Å/1399.77 Å ratio provides a good density diagnostics except for very low T combined with extreme non-Maxwellian situations.

  3. Millimeter emission lines in Orion A

    NASA Technical Reports Server (NTRS)

    Lovas, F. J.; Johnson, D. R.; Buhl, D.; Snyder, L. E.

    1976-01-01

    During the course of a search of Orion A for signals from three large organic molecules, several millimeter-wave lines from known interstellar molecules were observed. Results are reported for observations of methanol (CH3OH), methyl cyanide (CH3CN), methyl acetylene (CH3CCH), acetaldehyde (CH3CHO) and (Si-29)O. Emission signals from two hydrogen recombination lines (H41-alpha and H42-alpha) detected from the H II region of Orion A are also reported. Negative results were obtained for several millimeter-wave transitions of ethylene oxide, acetone, and cyclopropenone.

  4. Molecular Emission Line Formation in Prestellar Cores

    NASA Astrophysics Data System (ADS)

    Pavlyuchenkov, Ya.; Wiebe, D.; Shustov, B.; Henning, Th.; Launhardt, R.; Semenov, D.

    2008-12-01

    We investigate general aspects of molecular line formation under conditions typical of prestellar cores. Focusing on simple linear molecules, we study the formation of their rotational lines with radiative transfer simulations. We present a thermalization diagram to show the effects of collisions and radiation on the level excitation. We construct a detailed scheme (contribution chart) to illustrate the formation of emission-line profiles. This chart can be used as an efficient tool to identify which parts of the cloud contribute to a specific line profile. We show how molecular line characteristics for uniform model clouds depend on hydrogen density, molecular column density, and kinetic temperature. The results are presented in a two-dimensional plane to illustrate mutual effects of the physical factors. We also use a core model with a nonuniform density distribution and chemical stratification to study the effects of cloud contraction and rotation on spectral line maps. We discuss the main issues that should be taken into account when dealing with interpretation and simulation of observed molecular lines.

  5. UV line diagnostics of accretion disk winds in cataclysmic variables

    NASA Technical Reports Server (NTRS)

    Vitello, Peter; Shlosman, Isaac

    1992-01-01

    The IUE data base is used to analyze the UV line shapes of cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating bi-conical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the disk and boundary layer and treats 3-D line radiation transfer in the Sobolev approximation. It is found that winds from accretion disks provide a good fit for reasonable parameters to the observed UV lines which include the P Cygni profiles for low inclination systems and pure emission at large inclination. Disk winds are preferable to spherical winds which originate on the white dwarf because they (1) require a much lower ratio of mass loss rate to accretion rate and are therefore more plausible energetically, (2) provide a natural source for a bi-conical distribution of mass outflow which produces strong scattering far above the disk leading to P Cygni profiles for low inclination systems, and pure line emission profiles at high inclination with the absence of eclipses in UV lines, and (3) produce rotation broadened pure emission lines at high inclination.

  6. Ultraviolet line diagnostics of accretion disk winds in cataclysmic variables

    NASA Technical Reports Server (NTRS)

    Vitello, Peter; Shlosman, Isaac

    1993-01-01

    The IUE data base is used to analyze the UV line shapes of the cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating biconical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the disk and boundary layer and treats 3D line radiation transfer in the Sobolev approximation. It is found that winds from accretion disks provide a good fit for reasonable parameters to the observed UV lines which include the P Cygni profiles for low-inclination systems and pure emission at large inclination. Disk winds are preferable to spherical winds which originate on the white dwarf because they: (1) require a much lower ratio of mass-loss rate to accretion rate and are therefore more plausible energetically; (2) provide a natural source for a biconical distribution of mass outflow which produces strong scattering far above the disk leading to P Cygni profiles for low-inclination systems and pure line emission profiles at high inclination with the absence of eclipses in UV lines; and (3) produce rotation-broadened pure emission lines at high inclination.

  7. Line and continuum spectroscopy as diagnostic tools for gamma ray bursts

    SciTech Connect

    Liang, E.P.

    1990-12-01

    We review the theoretical framework of both line and continuum spectra formation in gamma ray bursts. These include the cyclotron features at 10's of keV, redshifted annihilation features at {approximately}400 keV, as well as other potentially detectable nuclear transition lines, atomic x-ray lines, proton cyclotron lines and plasma oscillation lines. By combining the parameters derived from line and continuum modeling we can try to reconstruct the location, geometry and physical conditions of the burst emission region, thereby constraining and discriminating the astrophysical models. Hence spectroscopy with current and future generations of detectors should provide powerful diagnostic tools for gamma ray bursters. 48 refs., 10 figs., 4 tabs.

  8. Linear Polarization Measurements of Chromospheric Emission Lines

    NASA Technical Reports Server (NTRS)

    Sheeley, N. R., Jr.; Keller, C. U.

    2003-01-01

    We have used the Zurich Imaging Stokes Polarimeter (ZIMPOL I) with the McMath-Pierce 1.5 m main telescope on Kitt Peak to obtain linear polarization measurements of the off-limb chromosphere with a sensitivity better than 1 x 10(exp -5). We found that the off-disk observations require a combination of good seeing (to show the emission lines) and a clean heliostat (to avoid contamination by scattered light from the Sun's disk). When these conditions were met, we obtained the following principal results: 1. Sometimes self-reversed emission lines of neutral and singly ionized metals showed linear polarization caused by the transverse Zeeman effect or by instrumental cross talk from the longitudinal Zeeman effect in chromospheric magnetic fields. Otherwise, these lines tended to depolarize the scattered continuum radiation by amounts that ranged up to 0.2%. 2. Lines previously known to show scattering polarization just inside the limb (such as the Na I lambda5889 D2 and the He I lambda5876 D3 lines) showed even more polarization above the Sun's limb, with values approaching 0.7%. 3. The O I triplet at lambda7772, lambda7774, and lambda7775 showed a range of polarizations. The lambda7775 line, whose maximum intrinsic polarizability, P(sub max), is less than 1%, revealed mainly Zeeman contributions from chromospheric magnetic fields. However, the more sensitive lambda7772 (P(sub max) = 19%) and lambda7774 (P(sub max) = 29%) lines had relatively strong scattering polarizations of approximately 0.3% in addition to their Zeeman polarizations. At times of good seeing, the polarization spectra resolve into fine structures that seem to be chromospheric spicules.

  9. Newly Identified Rydberg Emission Lines in Novae

    NASA Astrophysics Data System (ADS)

    Lynch, David K.; Rudy, R. J.; Bernstein, L. S.

    2008-09-01

    Newly Identified Rydberg Emission Lines in Novae David K. Lynch, Richard. J. Rudy (The Aerospace Corporation) & Lawrence S. Bernstein (Spectral Sciences, Inc.) Novae spectra in the near infrared frequently show a set of six emission lines that have not been positively identified (Williams, Longmore, & Geballe 1996, MNRAS, 279, 804; Lynch et al. 2001, AJ, 122, 2013; Rudy et al. 2002 ApJ, 573, 794; Lynch et al. 2004 Astron. J. 127, 1089-1097). These lines are at 0.8926, 1.1114, 1.1901, 1.5545, 2.0996 and 2.425 µm ± 0.005 µm. Krautter et al. (1984 A&A 137, 304) suggested that three of the lines were due to rydberg (hydrogenic) transitions in an unspecified atomic species that was in the 4th or 5th ionization stage (core charge = 4 & 5). We believe that Krautter et al.'s explanation is correct based on 4 additional lines that we have identified in the visible and near infrared spectrum of V723 Cassiopeiae. The observed Rydberg lines appear to originate from high angular momentum states with negligible quantum defects. The species cannot be determined with any certainty because in rydberg states, the outer electron sees a nucleus shielded by the inner electrons and together the inner atom appears to have a charge of +1, like hydrogen. As a result, the atom looks hydrogenic and species such as CV, NV, OV, MgV, SiV, etc. have their rydberg transitions at very similar wavelengths. All the lines represent permitted transitions, most likely formed by recombination. Atoms with core charges 4, 5 & 6 are rarely seen in the astrophysical environment because an extremely hot radiation field is necessary to ionize them. Thermonuclear runaways on the surface of a white dwarf can reach millions of degrees K, and thus there are enough X-ray photons available to achieve the necessary high ionization levels.

  10. Observations of southern emission-line stars

    NASA Technical Reports Server (NTRS)

    Henize, K. G.

    1976-01-01

    A catalog of 1929 stars showing H-alpha emission on photographic plates is presented which covers the entire southern sky south of declination -25 deg to a red limiting magnitude of about 11.0. The catalog provides previous designations of known emission-line stars equatorial (1900) and galactic coordinates, visual and photographic magnitudes, H-alpha emission parameters, spectral types, and notes on unusual spectral features. The objects listed include 16 M stars, 25 S stars, 37 carbon stars, 20 symbiotic stars, 40 confirmed or suspected T Tauri stars, 16 novae, 14 planetary nebulae, 11 P Cygni stars, 9 Bep stars, 87 confirmed or suspected Wolf-Rayet stars, and 26 'peculiar' stars. Two new T associations are discovered, one in Lupus and one in Chamaeleon. Objects with variations in continuum or H-alpha intensity are noted, and the distribution by spectral type is analyzed. It is found that the sky distribution of these emission-line stars shows significant concentrations in the region of the small Sagittarius cloud and in the Carina region.

  11. CORA: Emission Line Fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, Jan-Uwe; Wichmann, Rainer

    2011-12-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  12. CORA - emission line fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, J.-U.; Wichmann, R.

    2002-07-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  13. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    SciTech Connect

    Bonomo, F.; Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D.; Barbisan, M.; Pasqualotto, R.; Serianni, G.; Cristofaro, S.

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  14. Photoionization of Highly Charged Argon Ions and Their Diagnostic Lines

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.

    2012-06-01

    %TEXT OF YOUR ABSTRACT Lines of highly charged He-like and Li-like ions in the ultraviolet and X-ray regions provide useful diagnostics for the physical and chemical conditions of the astrophysical as well as fusion plasmas. For example, Ar XVII lines in a Syfert galaxy have been measured by the X-ray space observatory Chandra. Results on photoionization of Ar XVI and Ar XVII obtained from relativistic Breit-Pauli R-matrix method and close-coupling approximation will be presented. Important features for level-specific photoionization for the diagnostic w, x, y, z lines of He-like Ar XVII in the ultraviolet region will be illustrated. Although monotonous decay dominates the low energy photoionization for these ions, strong resonances appear in the high energy region indicating higher recombination, inverse process of photoionization, at high temperature. The spectra of the well known 22 diagnostics dielectronic satellite lines of Li-like Ar XVI will be shown produced from the the KLL resonances in photoionization. Acknowledgement: Partially supported by DOE, NSF; Computational work was carried out at the Ohio Supercomputer Center

  15. Spectral diagnostics of high energy emission in lambda Eri

    NASA Technical Reports Server (NTRS)

    Smith, Myron

    1995-01-01

    Multi-line observations of the optical spectrum of lambda Eri demonstrates that rapidly varying, low-velocity emissions occur in several He I lines even when H alpha shows no emission. A peculiar aspect of the He I emissions is that the ratio 5876/6678 is = 1. A theory of helium line formation generally admits two common emission mechanisms. The first is recombination/cascades, which is well known to give a ratio of greater than or equal to 3. The second is a non-LTE effect that occurs in hot (O-type) photospheres when resonance He I 584 radiation becomes transparent and drives single lines along into the emission. To accommodate a ratio of 5876/6678 = 1 may require that both processes sometimes operate at the same time, presumably in separate localities near the surface of this star.

  16. NON-EQUILIBRIUM IONIZATION EFFECTS ON THE DENSITY LINE RATIO DIAGNOSTICS OF O IV

    SciTech Connect

    Olluri, K.; Gudiksen, B. V.; Hansteen, V. H.

    2013-04-10

    The dynamic timescales in the solar atmosphere are shorter than the ionization and recombination times of many ions used for line ratio diagnostics of the transition region and corona. The long ionization and recombination times for these ions imply that they can be found far from their equilibrium temperatures, and spectroscopic investigations require more care before being trusted in giving correct information on local quantities, such as density and temperature. By solving the full time-dependent rate equations for an oxygen model atom in the three-dimensional numerical model of the solar atmosphere generated by the Bifrost code, we are able to construct synthetic intensity maps and study the emergent emission. We investigate the method of electron density diagnostics through line ratio analysis of the O IV 140.1 nm to the 140.4 nm ratio, the assumptions made in carrying out the diagnostics, and the different interpretations of the electron density. The results show big discrepancies between emission in statistical equilibrium and emission where non-equilibrium (NEQ) ionization is treated. Deduced electron densities are up to an order of magnitude higher when NEQ effects are accounted for. The inferred electron density is found to be a weighted mean average electron density along the line of sight and has no relation to the temperature of emission. This study shows that numerical modeling is essential for electron density diagnostics and is a valuable tool when the ions used for such studies are expected to be out of ionization equilibrium. Though this study has been performed on the O IV ion, similar results are also expected for other transition region ions.

  17. Fe X Emission Lines in Solar and Stellar Spectra

    NASA Astrophysics Data System (ADS)

    Foster, V. J.; Mathioudakis, M.; Keenan, F. P.; Drake, J. J.; Widing, K. G.

    1996-12-01

    Theoretical electron density sensitive emission line ratios involving Fe X 3s23p5-3s23p43d transitions in the 170-190 Å wavelength range are compared with observational data for a solar active region and flares, obtained during the Skylab mission, and Cen and Procyon observations from the Extreme Ultraviolet Explorer (EUVE) satellite. Electron densities derived from the majority of the ratios are consistent for the events but are in poor agreement with the values of Ne estimated from diagnostic lines in other species observed in the spectra, casting doubt on the accuracy of the theoretical line ratio calculations and, hence, the atomic data of Mohan et al. used in their derivation. At low Ne, the present ratios are significantly different from those of Young et al., while the latter imply densities that are in somewhat better agreement with densities derived from other diagnostics. This would appear to indicate that the electron impact excitation rates of Bhatia & Doschek adopted by Young et al. are to be preferred over the Mohan et al. results.

  18. EVOLUTION OF [O III] {lambda}5007 EMISSION-LINE PROFILES IN NARROW EMISSION-LINE GALAXIES

    SciTech Connect

    Wang, J.; Mao, Y. F.; Wei, J. Y.

    2011-11-01

    The active galactic nucleus (AGN)-host co-evolution issue is investigated here by focusing on the evolution of the [O III] {lambda}5007 emission-line profile. A large sample of narrow emission-line galaxies is selected from the Max-Planck Institute for Astrophysics/Johns Hopkins University Sloan Digital Sky Survey DR7 catalog to simultaneously measure both the [O III] line profile and circumnuclear stellar population in an individual spectrum. By requiring that (1) the [O III] line signal-to-noise ratio is larger than 30 and (2) the [O III] line width is larger than the instrumental resolution by a factor of two, our sample is narrowed down to 2333 Seyfert galaxies/LINERs (AGNs), 793 transition galaxies, and 190 star-forming galaxies. In addition to the commonly used profile parameters (i.e., line centroid, relative velocity shift, and velocity dispersion), two dimensionless shape parameters, skewness and kurtosis, are used to quantify the line shape deviation from a pure Gaussian function. We show that the transition galaxies are systematically associated with narrower line widths and weaker [O III] broad wings than the AGNs, which implies that the kinematics of emission-line gas are different in the two kinds of objects. By combining the measured host properties and line shape parameters, we find that the AGNs with stronger blue asymmetries tend to be associated with younger stellar populations. However, a similar trend is not identified in the transition galaxies. The failure likely results from a selection effect in which the transition galaxies are systematically associated with younger stellar populations than the AGNs. The evolutionary significance revealed here suggests that both narrow-line region kinematics and outflow feedback in AGNs co-evolve with their host galaxies.

  19. Evolution of [O III] λ5007 Emission-line Profiles in Narrow Emission-line Galaxies

    NASA Astrophysics Data System (ADS)

    Wang, J.; Mao, Y. F.; Wei, J. Y.

    2011-11-01

    The active galactic nucleus (AGN)-host co-evolution issue is investigated here by focusing on the evolution of the [O III] λ5007 emission-line profile. A large sample of narrow emission-line galaxies is selected from the Max-Planck Institute for Astrophysics/Johns Hopkins University Sloan Digital Sky Survey DR7 catalog to simultaneously measure both the [O III] line profile and circumnuclear stellar population in an individual spectrum. By requiring that (1) the [O III] line signal-to-noise ratio is larger than 30 and (2) the [O III] line width is larger than the instrumental resolution by a factor of two, our sample is narrowed down to 2333 Seyfert galaxies/LINERs (AGNs), 793 transition galaxies, and 190 star-forming galaxies. In addition to the commonly used profile parameters (i.e., line centroid, relative velocity shift, and velocity dispersion), two dimensionless shape parameters, skewness and kurtosis, are used to quantify the line shape deviation from a pure Gaussian function. We show that the transition galaxies are systematically associated with narrower line widths and weaker [O III] broad wings than the AGNs, which implies that the kinematics of emission-line gas are different in the two kinds of objects. By combining the measured host properties and line shape parameters, we find that the AGNs with stronger blue asymmetries tend to be associated with younger stellar populations. However, a similar trend is not identified in the transition galaxies. The failure likely results from a selection effect in which the transition galaxies are systematically associated with younger stellar populations than the AGNs. The evolutionary significance revealed here suggests that both narrow-line region kinematics and outflow feedback in AGNs co-evolve with their host galaxies.

  20. Line Emission from Radiation-pressurized H II Regions. I. Internal Structure and Line Ratios

    NASA Astrophysics Data System (ADS)

    Yeh, Sherry C. C.; Verdolini, Silvia; Krumholz, Mark R.; Matzner, Christopher D.; Tielens, Alexander G. G. M.

    2013-05-01

    The emission line ratios [O III] λ5007/Hβ and [N II] λ6584/Hα have been adopted as an empirical way to distinguish between the fundamentally different mechanisms of ionization in emission-line galaxies. However, detailed interpretation of these diagnostics requires calculations of the internal structure of the emitting H II regions, and these calculations depend on the assumptions one makes about the relative importance of radiation pressure and stellar winds. In this paper, we construct a grid of quasi-static H II region models to explore how choices about these parameters alter H II regions' emission line ratios. We find that when radiation pressure is included in our models, H II regions reach a saturation point beyond which further increase in the luminosity of the driving stars does not produce any further increase in effective ionization parameter, and thus does not yield any further alteration in an H II region's line ratio. We also show that if stellar winds are assumed to be strong, the maximum possible ionization parameter is quite low. As a result of this effect, it is inconsistent to simultaneously assume that H II regions are wind-blown bubbles and that they have high ionization parameters; some popular H II region models suffer from this inconsistency. Our work in this paper provides a foundation for a companion paper in which we embed the model grids we compute here within a population synthesis code that enables us to compute the integrated line emission from galactic populations of H II regions.

  1. Emission line spectropolarimetry and circumstellar structures

    NASA Astrophysics Data System (ADS)

    Vink, Jorick S.

    2015-10-01

    We discuss the role of linear emission-line polarimetry in a wide set of stellar environments, involving the accretion disks around young pre-main sequence stars, to the aspherical outflows from O stars, luminous blue variables and Wolf-Rayet stars, just prior to explosion as a supernova or a gamma-ray burst. We predict subtle QU line signatures, such as single/double QU loops for un/disrupted disks. Whilst there is plenty of evidence for single QU loops, suggesting the presence of disrupted disks around young stars, current sensitivity (with S/N of order 1000) is typically not sufficient to allow for quantitative 3D Monte Carlo modeling. However, the detection of our predicted signatures is expected to become feasible with the massive improvement in sensitivity of extremely large mirrors.

  2. Passive optical diagnostic of Xe-propelled Hall thrusters. I. Emission cross sections

    SciTech Connect

    Chiu Yuhui; Austin, Brad L.; Williams, Skip; Dressler, Rainer A.; Karabadzhak, George F.

    2006-06-01

    This paper presents a set of xenon apparent emission excitation cross sections for emission lines that have diagnostic value in the analysis of Xe-propelled Hall thruster plasmas. Emission cross sections are presented for three excitation processes involving ground-state xenon atoms: e{sup -}+Xe, Xe{sup +}+Xe, and Xe{sup 2+}+Xe. The cross sections are derived from luminescence spectra produced at single-collision conditions. Apparent emission excitation cross sections are tabulated for 12 visible and 8 near-infrared lines for electron energies ranging from 10 to 70 eV. In case of the near-infrared lines, radiation trapping effects are accounted for by measuring the detailed pressure dependence of the apparent emission cross sections and extrapolating to zero pressure. A semiempirical expression for the pressure dependence is derived that allows zero-pressure extrapolation from threshold to 70 eV. Ion-induced cross sections are reported for the same emission lines at an energy per unit charge E/q of 300 eV, chosen for typical Hall thruster operating voltages. Radiation trapping effects are negligible for the ion emission excitation cross sections between 0.1 and 2.0 mTorr in the present luminescence experiment.

  3. The resonance lines of MG2 as diagnostics of the upper solar chromosphere

    NASA Technical Reports Server (NTRS)

    Avrett, Eugene H.

    1994-01-01

    The resonance lines of singly ionized magnesium, the MgII h&k lines at about 280 nm, are two of the small number of lines in the solar spectrum that are optically thick in the chromospheric part of the solar atmosphere. Potentially these lines contain information on the initial temperature rise that occurs at the top of the photosphere. Unfortunately, few good observations of the lines exist due to their wavelength near 280 nm the ultraviolet. However, a fair number of observations (on the order of 200) are available from the data base of the UltraViolet Polarimeter and Spectrometer (UVSP) instrument that flew on board of NASA's Solar Maximum Mission (SMM) satellite. In addition, this data base contains a number of spectra that include the Mg I resonance line at (lambda)285.2nm, just longward of the h&k lines. The neutral magnesium line is not as strong as its ionic counterparts and samples slightly lower parts of the atmosphere. Its width is a sensitive diagnostic of the ionization balance between neutral and singly ionized magnesium, which determines the opacity scale (and formation height) of other diagnostically important MgI lines like the 457.1 nm intercombination line, the magnesium b lines and the infrared MgI emission lines near 12 microns. Analysis of the observed line profiles shows that it is necessary to include the effects of partial frequency redistribution (PRD) in the formation of the line as in the case of the h&k lines. This implies that the core of the line is very sensitive to the way scattering is treated in the modeling of the line, and in turn this allows us to separate the uncertain effects in the atomic data (viz. the Van der Waals broadening) from the uncertainties in the underlying atmospheric model. The main objective of this research was to compare observed spectra of the magnesium resonance lines against theoretical line profiles calculated from recent models of the solar atmosphere by Fontenla et al., hereafter called FAL. These

  4. A NEW CALCULATION OF Ne IX LINE DIAGNOSTICS

    SciTech Connect

    Smith, Randall K.; Chen Guoxin; Kirby, Kate; Brickhouse, Nancy S.

    2009-07-20

    We describe the effect that new atomic calculations, including fully relativistic R-matrix calculations of collisional excitation rates and level-specific dielectronic and radiative recombination rates, have on line ratios from the astrophysically significant ion Ne IX. The new excitation rates systematically change some predicted Ne IX line ratios by 25% at temperatures at or below the temperature of maximum emissivity (4 x 10{sup 6} K), while the new recombination rates lead to systematic changes at higher temperatures. The new line ratios are shown to agree with observations of Capella and {sigma}{sup 2} CrB significantly better than older line ratios, showing that 25%-30% accuracy in atomic rates is inadequate for high-resolution X-ray observations from existing spectrometers.

  5. Line emission from H II blister models

    NASA Technical Reports Server (NTRS)

    Rubin, R. H.

    1984-01-01

    Numerical techniques to calculate the thermal and geometric properties of line emission from H II 'blister' regions are presented. It is assumed that the density distributions of the H II regions are a function of two dimensions, with rotational symmetry specifying the shape in three-dimensions. The thermal and ionization equilibrium equations of the problem are solved by spherical modeling, and a spherical sector approximation is used to simplify the three-dimensional treatment of diffuse ionizing radiation. The global properties of H II 'blister' regions near the edges of a molecular cloud are simulated by means of the geometry/density distribution, and the results are compared with observational data. It is shown that there is a monotonic increase of peak surface brightness from the i = 0 deg (pole-on) observational position to the i = 90 deg (edge-on) position. The enhancement of the line peak intensity from the edge-on to the pole-on positions is found to depend on the density, stratification, ionization, and electron temperature weighting. It is found that as i increases, the position of peak line brightness of the lower excitation species is displaced to the high-density side of the high excitation species.

  6. The Formation of IRIS Diagnostics. VII. The Formation of the OI 135.56 NM Line in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Lin, Hsiao-Hsuan; Carlsson, Mats

    2015-11-01

    The O i 135.56 nm line is covered by NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission which studies how the solar atmosphere is energized. We study here the formation and diagnostic potential of this line by means of non-local thermodynamic equilibrium modeling employing both 1D semi-empirical and 3D radiation magnetohydrodynamic models. We study the basic formation mechanisms and derive a quintessential model atom that incorporates essential atomic physics for the formation of the O i 135.56 nm line. This atomic model has 16 levels and describes recombination cascades through highly excited levels by effective recombination rates. The ionization balance O i/O ii is set by the hydrogen ionization balance through charge exchange reactions. The emission in the O i 135.56 nm line is dominated by a recombination cascade and the line is optically thin. The Doppler shift of the maximum emission correlates strongly with the vertical velocity in its line forming region, which is typically located at 1.0-1.5 Mm height. The total intensity of the line emission is correlated with the square of the electron density. Since the O i 135.56 nm line is optically thin, the width of the emission line is a very good diagnostic of non-thermal velocities. We conclude that the O i 135.56 nm line is an excellent probe of the middle chromosphere, and compliments other powerful chromospheric diagnostics of IRIS such as the Mg ii h & k lines and the C ii lines around 133.5 nm.

  7. A Diagnostic Test for Determining the Location of the GeV Emission in Powerful Blazars

    NASA Technical Reports Server (NTRS)

    Dotson, Amanda; Georganopoulos, Markos; Kazanas, Demosthenes; Perlman, Eric

    2011-01-01

    An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a clear diagnostic tool for testing whether the Ge V emission site is located within the sub-pc broad emission line (BLR) region or further out in the few pc scale molecular torus (MT) environment. Within the BLR the scatteri takes place at the onset of the Klein-Nishina regime, causing the electron cooling time to become almost energy independent and as a result, the variation of high-energy emission is expected to be achromatic. Contrarily, if the emission site is located outside the BLR, the expected GeY variability is energy-dependent and with amplitude increasing with energy. We demonstrate this using time-dependent numerical simulations of blazar variability.

  8. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, J.W.

    1991-05-08

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using, a metal hydride.

  9. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, J.W.

    1993-03-30

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  10. Atomic line emission analyzer for hydrogen isotopes

    DOEpatents

    Kronberg, James W.

    1993-01-01

    Apparatus for isotopic analysis of hydrogen comprises a low pressure chamber into which a sample of hydrogen is introduced and then exposed to an electrical discharge to excite the electrons of the hydrogen atoms to higher energy states and thereby cause the emission of light on the return to lower energy states, a Fresnel prism made at least in part of a material anomalously dispersive to the wavelengths of interest for dispersing the emitted light, and a photodiode array for receiving the dispersed light. The light emitted by the sample is filtered to pass only the desired wavelengths, such as one of the lines of the Balmer series for hydrogen, the wavelengths of which differ slightly from one isotope to another. The output of the photodiode array is processed to determine the relative amounts of each isotope present in the sample. Additionally, the sample itself may be recovered using a metal hydride.

  11. FE-XIII Infrared / FE-XIV Green Line Ratio Diagnostics (P55)

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; et al.

    2006-11-01

    aks.astro.itbhu@gmail.com We consider the first 27-level atomic model of Fe XIII (5.9 < log Te < 6.4 K) to estimate its ground level populations, taking account of electron as well as proton collisional excitations and de-excitations, radiative cascades, radiative excitations and de-excitations. Radiative cascade is important but the effect of dilution factor is negligible at higher electron densities. The 3 P1-3P0 and 3P2-3P1 transitions in the ground configuration 3s2 3p2 of Fe XIII result in two forbidden coronal emission lines in the infrared region, namely 10747 Å and 10798 Å., while the 5303 Å green line is formed in the 3s2 3p 2 2 ground configuration of Fe XIV as a result of P3 / 2 - P1 / 2 magnetic dipole transition. The line-widths of appropriate pair of forbidden coronal emission lines observed simultaneously can be useful diagnostic tool to deduce temperature and non-thermal velocity in the large scale coronal structures using intensity ratios of the lines as the temperature signature, instead of assuming ion temperature to be equal to the electron temperature. Since the line intensity ratios IG5303/IIR10747 and IG5303/IIR10798 have very week density dependence, they are ideal monitors of temperature mapping in the solar corona.

  12. An Intrinsic Baldwin Effect in the H Beta Broad Emission Line in the Spectrum of NGC 5548

    NASA Technical Reports Server (NTRS)

    Gilbert, Karoline M.; Peterson, Bradley M.

    2003-01-01

    We investigate the possibility of an intrinsic Baldwin effect (i.e., nonlinear emission-line response to continuum variations) in the broad HP emission line of the active galaxy NGC 5548 using crosscorrelation techniques to remove light-travel time effects from the data. We find a nonlinear relationship between the HP emission line and continuum fluxes that is in good agreement with theoretical predictions. We suggest that similar analysis of multiple lines might provide a useful diagnostic of physical conditions in the broad-line region.

  13. X-ray lines from MG VIII and SI X ions and their diagnostic use

    NASA Astrophysics Data System (ADS)

    Dwivedi, Bhola N.

    The solar X-ray emission lines from Mg VIII and Si X ions have been studied. The variation of the theoretical line-intensity ratios from Mg VIII and Si X as functions of electron density are found to be good density monitors of the emitting regions of solar plasma. The computed values of line intensity from these ions based on the Kopp and Orrall model have been used to derive the electron density of the quiet sun and coronal holes. Electron densities of 10 exp 9/cu cm and 4.6 x 10 exp 8/cu cm are estimated at the electron temperatures of 8 x 10 exp 5 K and 1.6 x 10 exp 6 K for the quiet sun whereas the respective values of 5.4 x 10 exp 8/cu cm and 1.7 x 10 exp 8/cu cm are obtained for the coronal holes. The line-intensity ratios studied here are independent of temperature variation and are therefore excellent candidates for electron-density diagnostics. However, observational data with improved spectral resolution is needed for using X-ray-line pairs studied for their diagnostic use.

  14. Atomic Data and Emission Line Intensities for CA VII

    NASA Technical Reports Server (NTRS)

    Landi, E.; Bhatia, A. K.

    2003-01-01

    In the present work we calculate energy levels, transition probabilities and electron-ion collisional excitation rates for the 3s(sup 2)3p(sup 2), 3s3p(sup 3) and 3s(sup 2)3p3d configurations of the silicon-like ion Ca VII. The total number of intermediate coupling levels considered is 27. Collision strengths are calculated at seven incident electron energies: 8, 10, 15, 20, 30,40 and 60 Ry, using the Distorted Wave approximation and a 5-configuration model. Excitation rate coefficients are calculated by assuming a Maxwellian distribution of velocities and are used to calculate level populations and line emissivities under the assumption of statistical equilibrium. Line intensity ratios are calculated and compared with observed values measured from SERTS and SOHO/CDS spectra. The diagnostic potential of Ca VII is demonstrated, with particular emphasis on the possibility to measure the Ne/Ca relative abundance through simultaneous observations of Ca VII and N VI lines. Ca VII proves to be an excellent tool for the study of the FIP effect in the solar transition region.

  15. IFU spectroscopy of 10 early-type galactic nuclei - II. Nuclear emission line properties

    NASA Astrophysics Data System (ADS)

    Ricci, T. V.; Steiner, J. E.; Menezes, R. B.

    2014-05-01

    Although it is well known that massive galaxies have central black holes, most of them accreting at low Eddington ratios, many important questions still remain open. Among them are the nature of the ionizing source, the characteristics and frequencies of the broad-line region and of the dusty torus. We report observations of 10 early-type galactic nuclei, observed with the Gemini Multi Object Spectrograph in integral field unit mode, installed on the Gemini South telescope, analysed with standard techniques for spectral treatment and compared with results obtained with principal component analysis Tomography (Paper I). We performed spectral synthesis of each spaxel of the data cubes and subtracted the stellar component from the original cube, leaving a data cube with emission lines only. The emission lines were decomposed in multi-Gaussian components. We show here that, for eight galaxies previously known to have emission lines, the narrow-line region can be decomposed in two components with distinct line widths. In addition to this, broad Hα emission was detected in six galaxies. The two galaxies not previously known to have emission lines show weak Hα+[N II] lines. All 10 galaxies may be classified as low-ionization nuclear emission regions in diagnostic diagrams and seven of them have bona fide active galactic nuclei with luminosities between 1040 and 1043 erg s-1. Eddington ratios are always <10-3.

  16. Diagnostics of the κ-distribution using Si III lines in the solar transition region

    NASA Astrophysics Data System (ADS)

    Dzifčáková, E.; Kulinová, A.

    2011-07-01

    Aims: The solar transition region satisfies the conditions for appearance of the non-thermal κ-distribution. We aim to prove the occurrence of the non-thermal κ-distribution in the solar transition region and diagnose its parameters. Methods: The intensity ratios of Si iii lines observed by SUMER in 1100-1320 Å region do not correspond to the line ratios computed under the assumption of the Maxwellian electron distribution. We computed a set of synthetic Si iii spectra for the electron κ-distributions with different values of the parameter κ. We had to include the radiation field in our calculations to explain the observed line ratios. We propose diagnostics of the parameter κ and other plasma parameters and analyze the effect of the different gradient of differential emission measures (DEM) on the presented calculations. Results: The used line ratios are sensitive to T, density and the parameter κ. All these parameters were determined from the SUMER observations for the coronal hole (CH), quiet Sun (QS) and active region (AR) using our proposed diagnostics. A strong gradient of DEM influences the diagnosed parameters of plasma. The essential contributions to the total line intensities do not correspond to single T but a wider range of T, and they originate in different atmospheric layers. The amount of the contributions from these atmospheric layers depends on the gradient of DEM and the shape of the electron distribution function. Conclusions: The κ-distribution is able to explain the observed Si iii line spectrum in the transition region. The degree of non-thermality increases with the activity of the solar region, it is lower for CH and higher for the AR. The DEM influences the diagnosed T and Ne but it has only little effect on the diagnostics of the parameter κ.

  17. Excitation of emission lines by fluorescence and recombination in IC 418

    NASA Astrophysics Data System (ADS)

    Escalante, Vladimir; Morisset, Cristophe; Georgiev, Leonid

    2012-08-01

    We predict intensities of lines of CII, NI, NII, OI and OII and compare them with a deep spectroscopic survey of IC 418 to test the effect of excitation of nebular emission lines by continuum fluorescence of starlight. Our calculations use a nebular model and a synthetic spectrum of its central star to take into account excitation of the lines by continuum fluorescence and recombination. The NII spectrum is mostly produced by fluorescence due to the low excitation conditions of the nebula, but many CII and OII lines have more excitation by fluorescence than recombination. In the neutral envelope, the NI permitted lines are excited by fluorescence, and almost all the OI lines are excited by recombination. Electron excitation produces the forbidden optical lines of OI, but continuum fluorescence excites most of the NI forbidden line intensities. Lines excited by fluorescence of light below the Lyman limit thus suggest a new diagnostic to explore the photodissociation region of a nebula.

  18. An objective prism survey of emission line galaxies

    NASA Astrophysics Data System (ADS)

    Liu, J.-Y.; Huang, Y.-W.; Feng, X.-C.

    1986-09-01

    The first list of emission line objects detected as part of an object prism survey of emission line galaxies begun in China in 1981 is presented. The instrument and observations are described, and the identification of emission-line galaxies is discussed. The spectral structural classification of the presented objects is addressed. On a dozen plates covering some 220 square degrees of sky, 50 emission line objects were detected, 47 of which are galaxies and the other three of which are planetary nebulae. Finding charts of the objects are presented.

  19. Alternative diagnostic diagrams and the `forgotten' population of weak line galaxies in the SDSS

    NASA Astrophysics Data System (ADS)

    Cid Fernandes, R.; Stasińska, G.; Schlickmann, M. S.; Mateus, A.; Vale Asari, N.; Schoenell, W.; Sodré, L.

    2010-04-01

    A numerous population of weak line galaxies (WLGs) is often left out of statistical studies on emission-line galaxies (ELGs) due to the absence of an adequate classification scheme, since classical diagnostic diagrams, such as [OIII]/Hβ versus [NII]/Hα (the BPT diagram), require the measurement of at least four emission lines. This paper aims to remedy this situation by transposing the usual divisory lines between star-forming (SF) galaxies and active galactic nuclei (AGN) hosts and between Seyferts and LINERs to diagrams that are more economical in terms of line quality requirements. By doing this, we rescue from the classification limbo a substantial number of sources and modify the global census of ELGs. More specifically, (1) we use the Sloan Digital Sky Survey Data Release 7 to constitute a suitable sample of 280000 ELGs, one-third of which are WLGs. (2) Galaxies with strong emission lines are classified using the widely applied criteria of Kewley et al., Kauffmann et al. and Stasińska et al. to distinguish SF galaxies and AGN hosts and Kewley et al. to distinguish Seyferts from LINERs. (3) We transpose these classification schemes to alternative diagrams keeping [NII]/Hα as a horizontal axis, but replacing Hβ by a stronger line (Hα or [OII]), or substituting the ionization-level sensitive [OIII]/Hβ ratio with the equivalent width of Hα (WHα). Optimized equations for the transposed divisory lines are provided. (4) We show that nothing significant is lost in the translation, but that the new diagrams allow one to classify up to 50 per cent more ELGs. (5) Introducing WLGs in the census of galaxies in the local Universe increases the proportion of metal-rich SF galaxies and especially LINERs. In the course of this analysis, we were led to make the following points. (i) The Kewley et al. BPT line for galaxy classification is generally ill-used. (ii) Replacing [OIII]/Hβ by WHα in the classification introduces a change in the philosophy of the distinction

  20. Lower hybrid emission diagnostics on the NASA Lewis bumpy torus

    NASA Technical Reports Server (NTRS)

    Mallavarpu, R.

    1977-01-01

    The feasibility of using RF emission near the lower hybrid frequency of the NASA Lewis Bumpy Torus plasma for diagnostic purposes is examined. The emission is detected using a spectrum analyzer and a 50 omega miniature coaxial antenna that is sensitive to the polarization of the incoming signal. The frequency shift of the lower hybrid emission peak is monitored as a function of the background pressure, electrode voltage, electrode ring configuration and the strength of the toroidal dc magnetic field. Simultaneous measurements of the average plasma density are made with a polarization diplexing microwave interferometer. Data derived from the experiment are discussed with reference to the following: (1) the strength of the dc magnetic field in the emitting region; (2) comparison of the lower hybrid plasma density with the average plasma density; and (3) validity of the cold plasma lower hybrid resonance formula in the high density operating regime of the bumpy torus plasma.

  1. Chemo-population multizone models for emission line evolution of star forming galaxies

    NASA Astrophysics Data System (ADS)

    Valle, G.; Shore, S. N.

    2007-02-01

    Aims:We apply the nonlinear chemo-population (CP) models for galactic star formation and abundance evolution to the prediction of emission line diagnostics. Methods: We interfaced the CP code with the photoionization code Cloudy. Using the self-consistently generated star forming rates and abundance histories we predict the time dependences of the nebular line emissivities from model H II regions. We also simulated some effects of collisions, stripping, and accretion events on the emission line diagnostics. Results: We find, despite using extremely simplified input fluxes (i.e. blackbodies scaled to a range of effective temperatures but without detailed model atmospheres or population synthesis), the models reproduce many features of the observations. In particular, we suggest that the line ratios for highly ionized species (e.g. [O III] vs. [N II]) are more sensitive to the galactic history, while the exclusively ionization diagnostics (e.g. [O II] vs. [O I]) are more sensitive to the underlying stellar population and the composite ultraviolet flux distribution. We discuss some reasons for this and conclude that a coupled treatment of the galactic population and chemical evolution is essential for interpretation of the data. We also find that collisional and stripped models cover a wider range in the diagnostic diagrams that provide clues to the environmental effects.

  2. Helium-Like Iron Line Temperature Diagnostics in Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Swartz, Douglas A.; Sulkanen, Martin E.

    1993-01-01

    The emission complex around 6.7 keV, arising from He-like Fe lines and their dielectronic satellites, has been observed at low resolution in a number of clusters of galaxies. With sufficient spectral resolution as in, e.g., solar flare observations, the ratio, G = (x + y + z)/w, of the intercombination (x and y) and forbidden (z) to the resonance (w) lines arising from the n = 2 level of the He-like ion, is a sensitive temperature diagnostic. We examine this role for G in the context of spatially and spectrally resolved observations of clusters of galaxies. The temperature behavior of this ratio is strongly dependent on the spectral resolution. We introduce an alternative definition for G that includes the contribution of satellite lines and improves the temperature fidelity of this diagnostic. We find that deprojection of the observed value of G along a line of sight through the cluster can yield accurate temperature profiles for temperatures in the range 10(exp 7)-10(exp 8) K that do not suffer from the cluster model uncertainties inherent in deconvolution of broad-band X-ray surface brightness profiles.

  3. Enhanced line emission from laser-produced plasmas

    NASA Technical Reports Server (NTRS)

    Timmer, C.; Srivastava, S. K.; Hall, T. E.; Fucaloro, A. F.

    1991-01-01

    This communication reports the first systematic study on background gas-induced spectral-line-emission enhancement from laser-produced plasmas. Line emission from aluminum plasmas was enhanced by factors of up to 35 by the introduction of He, Ne, Xe, or N2. The enhancement has been attributed to three-body recombination.

  4. Emission spectroscopy for coal-fired cyclone furnace diagnostics.

    PubMed

    Wehrmeyer, Joseph A; Boll, David E; Smith, Richard

    2003-08-01

    Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained. Spectra from all cyclone burners show emission lines for the trace elements Li, Na, K, and Rb, as well as the molecular species OH and CaOH. The Ca emission line is detected at the burner end of both the fuel-rich and fuel-lean cyclone furnaces but is not detected at the outlet ends of either furnace type. Along with the disappearance of Ca is a concomitant increase in the CaOH signal at the outlet end of both types of furnaces. The OH signal strength is in general stronger when viewing at the burner end rather than the exhaust end of both the fuel-rich and fuel-lean cyclone furnaces, probably due to high, non-equilibrium amounts of OH present inside the furnace. Only one molecular species was detected that could be used as a measure of air/fuel ratio: MgOH. It was detected at the burner end of fuel-rich cyclone furnaces but not detected in fuel-lean cyclone furnaces. More direct markers of air/fuel ratio, such as CO and O2 emission, were not detected, probably due to the generally weak nature of molecular emission relative to ambient blackbody emission present in the cyclone furnaces, even at ultraviolet wavelengths. PMID:14661846

  5. SIMPLE MODELS OF METAL-LINE ABSORPTION AND EMISSION FROM COOL GAS OUTFLOWS

    SciTech Connect

    Prochaska, J. Xavier; Rubin, Kate

    2011-06-10

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II {lambda}{lambda}2796, 2803 doublet and Fe II UV1 multiplet at {lambda} {approx} 2600 A, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Ly{alpha}, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission 'fills in' the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s{sup -1}, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z {approx} 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep

  6. Simple Models of Metal-line Absorption and Emission from Cool Gas Outflows

    NASA Astrophysics Data System (ADS)

    Prochaska, J. Xavier; Kasen, Daniel; Rubin, Kate

    2011-06-01

    We analyze the absorption and emission-line profiles produced by a set of simple, cool gas wind models motivated by galactic-scale outflow observations. We implement Monte Carlo radiative transfer techniques that track the propagation of scattered and fluorescent photons to generate one-dimensional spectra and two-dimensional spectral images. We focus on the Mg II λλ2796, 2803 doublet and Fe II UV1 multiplet at λ ≈ 2600 Å, but the results are applicable to other transitions that trace outflows (e.g., Na I, H I Lyα, Si II). By design, the resonance transitions show blueshifted absorption but one also predicts strong resonance and fine-structure line emission at roughly the systemic velocity. This line-emission "fills in" the absorption, reducing the equivalent width by up to 50%, shifting the absorption-line centroid by tens of km s-1, and reducing the effective opacity near systemic. Analysis of cool gas outflows that ignores this line emission may incorrectly infer that the gas is partially covered, measure a significantly lower peak optical depth, and/or conclude that gas at systemic velocity is absent (e.g., an interstellar or slowly infalling component). Because the Fe II lines are connected by optically thin transitions to fine-structure levels, their profiles more closely reproduce the intrinsic opacity of the wind. Together these results naturally explain the absorption and emission-line characteristics observed for star-forming galaxies at z < 1. We also study a scenario promoted to describe the outflows of z ~ 3 Lyman break galaxies and find profiles inconsistent with the observations due to scattered photon emission. Although line emission complicates the analysis of absorption-line profiles, the surface brightness profiles offer a unique means of assessing the morphology and size of galactic-scale winds. Furthermore, the kinematics and line ratios offer powerful diagnostics of outflows, motivating deep, spatially extended spectroscopic

  7. Pulse-Heated Vertical Electron Cyclotron Emission Diagnostic

    NASA Astrophysics Data System (ADS)

    Voss, Keith Edward

    1995-01-01

    Determination of plasma parameters in tokamak experiments is of primary importance for learning to control and optimize fusion plasmas. Electron cyclotron emission (ECE) diagnostics play an important role in these experiments and are planned for future test reactors, since they require only simple collecting optics in the harsh reactor environment. A novel diagnostic system, which extracts information about plasma parameters by examining the ECE resulting from a perturbation of the plasma, was examined and applied on the PBX-M tokamak. This diagnostic uses a brief pulse of power from the lower hybrid current drive system to create a population of superthermal electrons. These electrons evolve according to the Fokker-Planck equation, which involves dependences on the magnetic field pitch, ion charge state, background density, and electric field. Coincident with the evolution of the electrons is the evolution of their ECE radiation. The diagnostic exploits the fact that the temporal changes in the radiation are dependent upon those parameters which affect the electrons. The analysis method, which compares measured experimental signal with simulated radiation (as functions of frequency and time) and determines most probable plasma parameter values, was computationally tested for effectiveness and robustness. The method was extended to include determination of parameters of the lower hybrid current drive power deposition. A measurement system, based on a grating polychromator, was assembled, tested, and calibrated, and pulse-heated vertical ECE data were collected from the PBX-M tokamak. A proof-of-principle test of the diagnostic yielded positive results, resulting in information about the lower hybrid current drive deposition location.

  8. Iron emission line from the spiral galaxy M 101

    NASA Astrophysics Data System (ADS)

    Yamauchi, Shigeo

    2016-06-01

    Archival Suzaku data of the face-on spiral galaxy M 101 were analyzed. An intense emission line at 6.72^{+0.10}_{-0.12}keV was detected in the central region. This line is identified with a K-line from He-like iron, which indicates the existence of a thin thermal plasma with a temperature of several keV. The iron line luminosity within the central 5'-radius region is estimated to be (2-12) × 1037 erg s-1. The origin of the iron emission line is discussed.

  9. Design of a beam emission spectroscopy diagnostic for negative ions radio frequency source SPIDER

    SciTech Connect

    Zaniol, B.; Pasqualotto, R.; Barbisan, M.

    2012-04-15

    A facility will be built in Padova (Italy) to develop, commission, and optimize the neutral beam injection system for ITER. The full scale prototype negative ion radio frequency source SPIDER, featuring up to 100 kV acceleration voltage, includes a full set of diagnostics, required for safe operation and to measure and optimize the beam performance. Among them, beam emission spectroscopy (BES) will be used to measure the line integrated beam uniformity, divergence, and neutralization losses inside the accelerator (stripping losses). In the absence of the neutralization stage, SPIDER beam is mainly composed by H{sup -} or D{sup -} particles, according to the source filling gas. The capability of a spectroscopic diagnostic of an H{sup -} (D{sup -}) beam relies on the interaction of the beam particles with the background gas particles. The BES diagnostic will be able to acquire the H{sub {alpha}} (D{sub {alpha}}) spectrum from up to 40 lines of sight. The system is capable to resolve stripping losses down to 2 keV and to measure beam divergence with an accuracy of about 10%. The design of this diagnostic is reported, with discussion of the layout and its components, together with simulations of the expected performance.

  10. A New Interpretation for the Variation in Starburst Galaxy Emission Line Spectra

    NASA Astrophysics Data System (ADS)

    Richardson, Chris T.; Allen, James T.; Baldwin, Jack A.; Hewett, Paul C.; Ferland, Gary J.; Meskhidze, Helen

    2015-01-01

    Starburst galaxies have been easily distinguished from AGN using diagnostic emission line ratio diagrams constraining their excitation mechanism. Previous modeling of the star forming (SF) galaxy sequence outlined on the BPT diagram has led to the interpretation that high metallicity SF galaxies and low ionization SF galaxies are synonymous. Here, we present a new interpretation. Using a large sample of low-z SDSS galaxies, we co-added similar spectra of pure star forming galaxies allowing many weaker emission lines to act as consistency checks on strong line diagnostics. For the first time, we applied a locally optimally-emitting cloud (LOC) model to understand the physical reason for the variation in starburst galaxy emission line spectra. We fit over twenty diagnostic diagrams constraining the excitation mechanism, SED, temperature, density, metallicity, and grain content, making this work far more constrained than previous studies. Our results indicate that low luminosity SF galaxies could simply have less concentrated regions of ionized gas compared to their high luminosity counterparts, but have similar metallicities, thus requiring reevaluation about underlying nature of star forming galaxies.

  11. The Mg 2 lines as diagnostic of PMS nature in Herbig Ae/Be stars

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The main objective of this program was to observe some newly discovered and previously unobserved Herbig Ae/Be (HAeBe) stars with IUE. A previous archival study suggested that there was a full range of profiles in the Mg II lines for these objects; ranging from the double peak emission to the narrow absorption lines. It has been found that by studying the IUE data of main sequence B and classical Be stars that the P Cygni profiles in the Mg II lines in HAeBe stars are truly unique and are the signature of accelerating winds in their extended circumstellar material. The arguement, for the purposes of this proposal, that the structure of the Mg II lines was a superior diagnostic of the dynamical activity and ultimately the PMS nature of these objects. This program was a follow up study of several interesting intermediate-mass stars with the goal of classifying these objects based on the shape of their MG II lines. A list of publications resulting from this research is included.

  12. Optical emission line monitor with background observation and cancellation

    DOEpatents

    Goff, David R.; Notestein, John E.

    1986-01-01

    A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interferring blackbody radiation by greater than 20 dB.

  13. Optical emission line monitor with background observation and cancellation

    DOEpatents

    Goff, D.R.; Notestein, J.E.

    1985-01-04

    A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium D-line emission in coal combustion, may be detected in the presence of interferring background or blackbody radiation with emissions much greater in intensity than that of the emission line being detected. A bifurcated fiber optic light guide is adapted at the end of one branch to view the combustion light which is guided to a first bandpass filter, adapted to the common trunk end of the fiber. A portion of the light is reflected back through the common trunk portion of the fiber to a second bandpass filter adapted to the end of the other branch of the fiber. The first filter bandpass is centered at a wavelength corresponding to the emission line to be detected with a bandwidth of about three nanometers (nm). The second filter is centered at the same wavelength but having a width of about 10 nm. First and second light detectors are located to view the light passing through the first and second filters respectively. Thus, the second detector is blind to the light corresponding to the emission line of interest detected by the first detector and the difference between the two detector outputs is uniquely indicative of the intensity of only the combustion flame emission of interest. This instrument can reduce the effects of interfering blackbody radiation by greater than 20 dB.

  14. Emission lines in the long period Cepheid l Carinae

    NASA Technical Reports Server (NTRS)

    Boehm-Vitense, Erika; Love, Stanley G.

    1991-01-01

    For the Cepheid (l) Carinae with a pulsation period of 35.5 days we have studied the emission line fluxes as a function of pulsational phase in order to find out whether we see chromosphere and transition layer emission or whether we see emission due to an outward moving shock. All emission lines show a steep increase in flux shortly before maximum light suggestive of a shock moving through the surface layers. The large ratio of the C IV to C II line fluxes shows that these are not transition layer lines. During maximum light the large ratio of the C IV to C II line fluxes also suggests that we see emission from a shock with velocities greater than 100 km/sec such that C IV emission can be excited. With such velocities mass outflow appears possible. The variations seen in the Mg II line profiles show that there is an internal absorption over a broad velocity band independent of the pulsational phase. We attribute this absorption to a circumstellar 'shell'. This 'shell' appears to be seen also as spatially extended emission in the O I line at 1300 angstrom, which is probably excited by resonance with Ly beta.

  15. The 22 GHz Water Maser Line: A New Diagnostic Tool for Extrasolar Planet Search

    NASA Astrophysics Data System (ADS)

    Cosmovici, Cristiano; Pogrebenko, Sergej; Montebugnoli, Stelio; Maccaferri, Giuseppe

    The impact of 21 nuclei of Comet Shoemaker-Levy with the atmosphere of Jupiter in July 1994, permitted the detection of the 22 GHz water MASER line for the first time in the Solar System. This emission line was originated by a water cloud released from cometary ices after the explosion of the nuclei in the upper atmosphere. Our measurements have shown that, under particular physical conditions, water MASER emission can be observed from planetary atmospheres. Thus water (and probably other molecules like SiO) MASER emission can be used as a powerful diagnostic tool for planetary search outside the Solar System, since comets are able to deliver huge amounts of water into planetary atmospheres, increasing the probability of life development. We therefore started a search program with the 32m dish of the Medicina Radiotelescope using a 132,000 multichannel spectrometer in order to cover Doppler shifts due to planetary rotation. In this paper we will illustrate the feasibility, the technique used, and the first selected targets for the search within 50 ly.

  16. Enterprise utilization of "always on-line" diagnostic study archive.

    PubMed

    McEnery, Kevin W; Suitor, Charles T; Thompson, Stephen K; Shepard, Jeffrey S; Murphy, William A

    2002-01-01

    To meet demands for enterprise image distribution, an "always on-line" image storage archive architecture was implemented before soft copy interpretation. It was presumed that instant availability of historical diagnostic studies would elicit a substantial utilization. Beginning November 1, 2000 an enterprise distribution archive was activated (Stentor, SanFrancisco, CA). As of August 8, 2001, 83,052 studies were available for immediate access without the need for retrieval from long-term archive. Image storage and retrieval logs for the period from June 12, 2001 to August 8, 2001 were analyzed. A total of 41,337 retrieval requests were noted for the 83,052 studies available as August 8, 2001. Computed radiography represented 16.8% of retrieval requests; digital radiography, 16.9%; computed tomography (CT), 44.5%; magnetic resonance (MR), 19.2%; and ultrasonography, 2.6%. A total of 51.5% of study retrievals were for studies less than 72 hours old. Study requests for cases greater than 100 days old represented 9.9% of all accessions, 9.7% of CT accessions, and 15.4% of MR accessions. Utilization of the archive indicates a substantial proportion of study retrievals for studies less than 72 hours after study completion. However, significant interest in historical CT and MR examinations was shown. PMID:12105703

  17. On-line diagnostic system for power generators

    SciTech Connect

    Skormin, V.A.; Goodenough, G.S.; Huber, R.K.

    1996-12-31

    A novel approach to diagnostics of a power generator is developed. It utilizes readily available data acquired by the existing computer-based monitoring/control system. Diagnostic procedures detect various trends in the generator data and interpret these trends in the generator data and interpret these trends as changes in the generator performance caused by incipient failures. Results of trend analyses, subjected to statistical validation, facilitate failure prediction and identification thus providing the justification for service when needed. The procedures are incorporated in a diagnostic system implemented in a PC interfaced with the existing VAX-based process monitoring and control system. The diagnostic system provides graphical display of the diagnostic messages.

  18. Emission lines in the long-period Cepheid l Carinae

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, Erika; Love, Stanley G.

    1994-01-01

    For the Cepheid l Carinae, with a pulsation period of 35.5 days, we have studied the emission-line fluxes as a function of pulsational phase in order to find out whether we see chromospheric and transition-layer emission due to an outward-moving shock. All emission lines show a steep increase in flux shortly before maximum light, suggestive of a shock moving through the surface layers. The large ratio of C IV to C II line fluxes shows that these are not transition-layer lines. During maximum light the large ratio of the large ratio of the C IV to C II line fluxes also suggests that we see emission from a shock with velocities greater than 100 km/s such that C IV emission can be excited. With such velocities mass outflow appears possible. The variations seen in the MG II line profiles show that there is an external absorption over a broad velocity band independent of the pulsation phase. We attribute this absorption to a circumstellar 'shell.' This 'shell' appears to be seen also as spatially extended emission in the O I line at 1300 A, which is probably excited by resonance with Ly beta.

  19. Coronal Physics and the Chandra Emission Line Project

    NASA Technical Reports Server (NTRS)

    Brickhouse, Nancy

    1999-01-01

    With the launch of the Chandra X-ray Observatory, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources will provide not only invaluable calibration data, but will also give us benchmarks for plasma spectral modeling codes. These codes are to interpret data from stellar coronae, galaxies and clusters of galaxies. supernova remnants and other astrophysical sources, but they have been called into question in recent years as problems with understanding moderate resolution ASCA and EUVE data have arisen. The Emission Line Project is a collaborative effort to improve the models, with Phase 1 being the comparison of models with observed spectra of Capella, Procyon, and HR, 1099. Goals of these comparisons are (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. A critical issue in exploiting the coronal data for these purposes is to understand the extent to which common simplifying assumptions (coronal equilibrium, time-independence, negligible optical depth) apply. We will discuss recent advances in our understanding of stellar coronae in this context.

  20. Fine structure line emission from supergiants

    NASA Technical Reports Server (NTRS)

    Haas, Michael R.; Glassgold, Alfred E.; Tielens, Alexander G. G. M.

    1995-01-01

    We have detected (O I) 63 micron and (Si II) 35 micron emission from the oxygen-rich, M supergiants alpha Orionis (Betelgeuse), alpha Scorpii (Antares), and alpha Herculis (Rasalgethi). The measured fluxes indicate that the emission originates in dense, warm gas in the inner envelope or transition region where molecules and dust are expected to form and the acceleration of the wind occurs. Mass-loss rates are derived, evidence for time variability is presented, and results for other evolved stars are included.

  1. Fine structure line emission from supergiants

    NASA Astrophysics Data System (ADS)

    Haas, Michael R.; Glassgold, Alfred E.; Tielens, Alexander G. G. M.

    We have detected (O I) 63 micron and (Si II) 35 micron emission from the oxygen-rich, M supergiants alpha Orionis (Betelgeuse), alpha Scorpii (Antares), and alpha Herculis (Rasalgethi). The measured fluxes indicate that the emission originates in dense, warm gas in the inner envelope or transition region where molecules and dust are expected to form and the acceleration of the wind occurs. Mass-loss rates are derived, evidence for time variability is presented, and results for other evolved stars are included.

  2. The Diagnostic Potential of Transition Region Lines Undergoing Transient Ionization in Dynamic Events

    NASA Astrophysics Data System (ADS)

    Doyle, J. G.; Giunta, A.; Singh, A.; Madjarska, M. S.; Summers, H.; Kellett, B. J.; O'Mullane, M.

    2012-09-01

    We discuss the diagnostic potential of high cadence UV spectral data when transient ionization is considered. For this we use high cadence UV spectra taken during the impulsive phase of a solar flare (observed with instruments on-board the Solar Maximum Mission) which showed excellent correspondence with hard X-ray pulses. The ionization fraction of the transition region ion O v and, in particular, the contribution function for the O v 1371 Å line are computed within the Atomic Data and Analysis Structure, which is a collection of fundamental and derived atomic data and codes to manipulate them. Due to transient ionization, the O v 1371 Å line is enhanced in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature than in ionization equilibrium. The rise time and enhancement factor depend mostly on the electron density. The fractional increase in the O v 1371 Å emissivity due to transient ionization can reach a factor of two-four and can explain the fast response in the line flux of transition regions ions during the impulsive phase of flares solely as a result of transient ionization. This technique can be used to diagnose the electron temperature and density of solar flares observed with the forthcoming Interface Region Imaging Spectrograph.

  3. Evaluation of thermal helium beam and line-ratio fast diagnostic on the National Spherical Torus Experiment-Upgrade

    NASA Astrophysics Data System (ADS)

    Muñoz Burgos, J. M.; Agostini, M.; Scarin, P.; Stotler, D. P.; Unterberg, E. A.; Loch, S. D.; Schmitz, O.; Tritz, K.; Stutman, D.

    2016-05-01

    A 1-D kinetic collisional radiative model with state-of-the-art atomic data is developed and employed to simulate line emission to evaluate the Thermal Helium Beam (THB) diagnostic on NSTX-U. This diagnostic is currently in operation on RFX-mod, and it is proposed to be installed on NSTX-U. The THB system uses the intensity ratios of neutral helium lines 667.8, 706.5, and 728.1 nm to derive electron temperature (eV) and density (cm-3) profiles. The purpose of the present analysis is to evaluate the applications of this diagnostic for determining fast ( ∽ 4 μs ) electron temperature and density radial profiles on the scrape-off layer and edge regions of NSTX-U that are needed in turbulence studies. The diagnostic is limited by the level of detection of the 728.1 nm line, which is the weakest of the three. This study will also aid in future design of a similar 2-D diagnostic system on the divertor.

  4. Evaluation of thermal helium beam and line-ratio fast diagnostic on the National Spherical Torus Experiment-Upgrade

    DOE PAGESBeta

    Munoz Burgos, Jorge M.; Agostini, Matteo; Scarin, Paolo; Stotler, Daren P.; Unterberg, Ezekial A.; Loch, Stuart D.; Schmitz, Oliver; Tritz, Kevin; Stutman, Dan

    2015-05-06

    A 1-D kinetic collisional radiative model (CRM) with state-of-the-art atomic data is developed and employed to simulate line emission to evaluate the Thermal Helium Beam (THB) diagnostic on NSTX-U. This diagnostic is currently in operation on RFX-mod, and it is proposed to be installed on NSTX-U. The THB system uses the intensity ratios of neutral helium lines 667.8, 706.5, and 728.1 nm to derive electron temperature (eV ) and density (cm–3) profiles. The purpose of the present analysis is to evaluate the applications of this diagnostic for determining fast (~4 μs) electron temperature and density radial profiles on the scrape-offmore » layer (SOL) and edge regions of NSTX-U that are needed in turbulence studies. The diagnostic is limited by the level of detection of the 728.1 nm line, which is the weakest of the three. In conclusion, this study will also aid in future design of a similar 2-D diagnostic systems on the divertor.« less

  5. Evaluation of thermal helium beam and line-ratio fast diagnostic on the National Spherical Torus Experiment-Upgrade

    SciTech Connect

    Munoz Burgos, Jorge M.; Agostini, Matteo; Scarin, Paolo; Stotler, Daren P.; Unterberg, Ezekial A.; Loch, Stuart D.; Schmitz, Oliver; Tritz, Kevin; Stutman, Dan

    2015-05-06

    A 1-D kinetic collisional radiative model (CRM) with state-of-the-art atomic data is developed and employed to simulate line emission to evaluate the Thermal Helium Beam (THB) diagnostic on NSTX-U. This diagnostic is currently in operation on RFX-mod, and it is proposed to be installed on NSTX-U. The THB system uses the intensity ratios of neutral helium lines 667.8, 706.5, and 728.1 nm to derive electron temperature (eV ) and density (cm–3) profiles. The purpose of the present analysis is to evaluate the applications of this diagnostic for determining fast (~4 μs) electron temperature and density radial profiles on the scrape-off layer (SOL) and edge regions of NSTX-U that are needed in turbulence studies. The diagnostic is limited by the level of detection of the 728.1 nm line, which is the weakest of the three. In conclusion, this study will also aid in future design of a similar 2-D diagnostic systems on the divertor.

  6. Spectral classification of emission-line galaxies

    NASA Technical Reports Server (NTRS)

    Veilleux, Sylvain; Osterbrock, Donald E.

    1987-01-01

    A revised method of classification of narrow line active galaxies and H II region-like galaxies is proposed. It involves the line ratios (O III) lambda 5007/H beta, (N II) lambda 6583/H alpha, (S II) (lambda lambda 6716 = 6731)/H alpha, and (O I) lambda 6300/H alpha. These line ratios take full advantage of the physical distinction between the two types of objects and minimize the effects of reddening correction and errors in the flux calibration. Large sets of internally consistent data are used including new previously unpublished measurements. Prediction of recent photoionization models by power law spectra and by hot stars are compared with the observations. The classification is based on the observational data interpreted on the basis of these models.

  7. Spectral classification of emission-line galaxies

    SciTech Connect

    Veilleux, S.; Osterbrock, D.E.

    1987-02-01

    A revised method of classification of narrow-line active galaxies and H II region-like galaxies is proposed. It involves the line ratios which take full advantage of the physical distinction between the two types of objects and minimize the effects of reddening correction and errors in the flux calibration. Large sets of internally consistent data are used, including new, previously unpublished measurements. Predictions of recent photoionization models by power-law spectra and by hot stars are compared with the observations. The classification is based on the observational data interpreted on the basis of these models. 63 references.

  8. Nebular and auroral emission lines of [Cl III] in the optical spectra of planetary nebulae.

    PubMed

    Keenan, F P; Aller, L H; Ramsbottom, C A; Bell, K L; Crawford, F L; Hyung, S

    2000-04-25

    Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (T(e)) and density (N(e)) emission line ratios involving both the nebular (5517.7, 5537.9 A) and auroral (8433.9, 8480.9, 8500.0 A) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R(1) = I(5518 A)/I(5538 A) intensity ratio provides estimates of N(e) in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R(1) is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 A line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of T(e) when ratioed against the sum of the 5518 and 5538 A line fluxes. Similarly, the 8500.0 A line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 A is found to be blended with the He i 8480.7 A line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of T(e) when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 A is briefly discussed. PMID:10759562

  9. The Impact of Diffuse Ionized Gas on Emission-line Ratios and Gas Metallicity Measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Yan, Renbin; MaNGA Team

    2016-01-01

    Diffuse Ionized Gas (DIG) is prevalent in star-forming galaxies. Using a sample of galaxies observed by MaNGA, we demonstrate how DIG in star-forming galaxies impact the measurements of emission line ratios, hence the gas-phase metallicity measurements and the interpretation of diagnostic diagrams. We demonstrate that emission line surface brightness (SB) is a reasonably good proxy to separate HII regions from regions dominated by diffuse ionized gas. For spatially-adjacent regions or regions at the same radius, many line ratios change systematically with emission line surface brightness, reflecting a gradual increase of dominance by DIG towards low SB. DIG could significantly bias the measurement of gas metallicity and metallicity gradient. Because DIG tend to have a higher temperature than HII regions, at fixed metallicity DIG displays lower [NII]/[OII] ratios. DIG also show lower [OIII]/[OII] ratios than HII regions, due to extended partially-ionized regions that enhance all low-ionization lines ([NII], [SII], [OII], [OI]). The contamination by DIG is responsible for a substantial portion of the scatter in metallicity measurements. At different surface brightness, line ratios and line ratio gradients can differ systematically. As DIG fraction could change with radius, it can affect the metallicity gradient measurements in systematic ways. The three commonly used strong-line metallicity indicators, R23, [NII]/[OII], O3N2, are all affected in different ways. To make robust metallicity gradient measurements, one has to properly isolate HII regions and correct for DIG contamination. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or LINER-like regions.

  10. Nebular and auroral emission lines of [Cl iii] in the optical spectra of planetary nebulae

    PubMed Central

    Keenan, Francis P.; Aller, Lawrence H.; Ramsbottom, Catherine A.; Bell, Kenneth L.; Crawford, Fergal L.; Hyung, Siek

    2000-01-01

    Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (Te) and density (Ne) emission line ratios involving both the nebular (5517.7, 5537.9 Å) and auroral (8433.9, 8480.9, 8500.0 Å) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R1 = I(5518 Å)/I(5538 Å) intensity ratio provides estimates of Ne in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R1 is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 Å line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of Te when ratioed against the sum of the 5518 and 5538 Å line fluxes. Similarly, the 8500.0 Å line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 Å is found to be blended with the He i 8480.7 Å line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of Te when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 Å is briefly discussed. PMID:10759562

  11. A collinear self-emission and laser-backlighting imaging diagnostic

    SciTech Connect

    Bott, S. C.; Collins, G. IV; Gunasekera, K.; Mariscal, D.; Beg, F. N.; Haas, D. M.; Veloso, F.; Blesener, I. C.; Cahill, A. D.; Hoyt, C. L.; Kusse, B. R.; Hammer, D. A.

    2012-08-15

    In this work we demonstrate a design for obtaining laser backlighting (e.g., interferometry) and time-resolved extreme ultraviolet self-emission images along the same line-of-sight. This is achieved by modifying a single optical component in the laser collection optics with apertures and pinhole arrangements suitable for single or multiple frame imaging onto a gated detector, such as a microchannel plate. Test results for exploding wire experiments show that machining of the optic does not affect the overall quality of the recovered laser images, and that, even with a multiple frame system, the area sacrificed to achieve collinear imaging is relatively small. The diagnostics can therefore allow direct correlation of laser and self-emission images and their derived quantities, such as electron density in the case of interferometry. Simple methods of image correlation are also demonstrated.

  12. Line Emission from Optically Thick RelativisticAccretion Tori

    SciTech Connect

    Fuerst, Steven V.; Wu, Kinwah; /Mullard Space Sci. Lab.

    2007-09-14

    We calculate line emission from relativistic accretion tori around Kerr black holes and investigate how the line profiles depend on the viewing inclination, spin of the central black hole, parameters describing the shape of the tori, and spatial distribution of line emissivity on the torus surface. We also compare the lines with those from thin accretion disks. Our calculations show that lines from tori and lines from thin disks share several common features. In particular, at low and moderate viewing inclination angles they both have asymmetric double-peaked profiles with a tall, sharp blue peak and a shorter red peak which has an extensive red wing. At high viewing inclination angles they both have very broad, asymmetric lines which can be roughly considered as single-peaked. Torus and disk lines may show very different red and blue line wings, but the differences are due to the models for relativistic tori and disks having differing inner boundary radii. Self-eclipse and lensing play some role in shaping the torus lines, but they are effective only at high inclination angles. If inner and outer radii of an accretion torus are the same as those of an accretion disk, their line profiles show substantial differences only when inclination angles are close to 90{sup o}, and those differences are manifested mostly at the central regions of the lines instead of the wings.

  13. Significant contribution of the Cerenkov line-like radiation to the broad emission lines of quasars

    SciTech Connect

    Liu, D. B.; You, J. H.; Chen, W. P.; Chen, L. E-mail: dliu@cfa.Harvard.edu

    2014-01-01

    The Cerenkov line-like radiation in a dense gas (N {sub H} > 10{sup 13} cm{sup –3}) is potentially important in the exploration of the optical broad emission lines of quasars and Seyfert 1 galaxies. With this quasi-line emission mechanism, some long standing puzzles in the study of quasars could be resolved. In this paper, we calculate the power of the Cerenkov line-like radiation in dense gas and compare with the powers of other radiation mechanisms by a fast electron to confirm its importance. From the observed gamma-ray luminosity of 3C 279, we show that the total number of fast electrons is sufficiently high to allow effective operation of the quasi-line emission. We present a model calculation for the luminosity of the Cerenkov Lyα line of 3C 279, which is high enough to compare with observations. We therefore conclude that the broad line of quasars may be a blend of the Cerenkov emission line with the real line produced by the bound-bound transition. A new approach to the absorption of the Cerenkov line is presented with the method of escape probability, which markedly simplifies the computation in the optically thick case. The revised set of formulae for the Cerenkov line-like radiation is more convenient in applications.

  14. Modeling and simulation of a beam emission spectroscopy diagnostic for the ITER prototype neutral beam injector

    SciTech Connect

    Barbisan, M. Zaniol, B.; Pasqualotto, R.

    2014-11-15

    A test facility for the development of the neutral beam injection system for ITER is under construction at Consorzio RFX. It will host two experiments: SPIDER, a 100 keV H{sup −}/D{sup −} ion RF source, and MITICA, a prototype of the full performance ITER injector (1 MV, 17 MW beam). A set of diagnostics will monitor the operation and allow to optimize the performance of the two prototypes. In particular, beam emission spectroscopy will measure the uniformity and the divergence of the fast particles beam exiting the ion source and travelling through the beam line components. This type of measurement is based on the collection of the H{sub α}/D{sub α} emission resulting from the interaction of the energetic particles with the background gas. A numerical model has been developed to simulate the spectrum of the collected emissions in order to design this diagnostic and to study its performance. The paper describes the model at the base of the simulations and presents the modeled H{sub α} spectra in the case of MITICA experiment.

  15. An Examination of Strong-line Metallicity Diagnostics with Direct Gas-Phase Metallicities at Higher Redshifts

    NASA Astrophysics Data System (ADS)

    Ly, Chun; Rigby, Jane R.; Malkan, Matthew Arnold; Malhotra, Sangeeta

    2016-01-01

    The [OIII]λ4363 nebular emission line, which provides the most reliable determination of the gas metallicity by measuring the electron temperature of the gas, is intrinsically weak. As such, most metallicity studies at both low and high redshifts have utilized "strong-line" metallicity calibrations, such as [NII]λ6583/Hα or R23 = ([OII]+[OIII])/Hβ. However, there are growing concerns that these diagnostics may not be used for evolutionary studies due to differences in the physical conditions (e.g., density, ionization, abundance ratios) of the interstellar gas in galaxies. A clear demonstration for this concern is the offset on the Baldwin-Phillips-Terlevich diagnostic diagram ([OIII]λ5007/Hβ vs. [NII]λ6583/Hα) for high-z star-forming galaxies from local star-forming galaxies.To examine this issue, we investigate the accuracy that commonly-used strong-line diagnostics can explain the direct oxygen abundances. Here, we use a sample of ~100 low-mass galaxies at z=0.07 to 1.0 with detections of the [OIII]λ4363 emission line from Keck and MMT optical spectroscopy. These galaxies are pre-selected for their strong nebular emission lines from the Subaru Deep Field and the DEEP2 Survey. Utilizing the optical emission lines, we argue that "R23" is not a reliable diagnostic and that discrepancies from [OIII]λ4363-based metallicity cannot be explained simply by higher gas densities or higher ionization parameter. We do find that the [NII]-based metallicity diagnostics of Pettini & Pagel (2004) are in agreement with [OIII]λ4363-based metallicity at z~0.5. There is, however, a sub-population (25%) where [NII]-based estimates are overestimating the oxygen metallicities. We argue that enhanced nitrogen abundances, relative to oxygen, is responsible for this significant (~0.5 dex) offset in metallicity. We present preliminary results for a revised metallicity calibration that considers the N/O abundance ratio.

  16. ACCRETION DISK TEMPERATURES OF QSOs: CONSTRAINTS FROM THE EMISSION LINES

    SciTech Connect

    Bonning, E. W.; Shields, G. A.; Stevens, A. C.; Salviander, S. E-mail: shields@astro.as.utexas.edu E-mail: triples@astro.as.utexas.edu

    2013-06-10

    We compare QSO emission-line spectra to predictions based on theoretical ionizing continua of accretion disks. The observed line intensities do not show the expected trend of higher ionization with theoretical accretion disk temperature as predicted from the black hole mass and accretion rate. Consistent with earlier studies, this suggests that the inner disk does not reach temperatures as high as expected from standard disk theory. Modified radial temperature profiles, taking account of winds or advection in the inner disk, achieve better agreement with observation. The emission lines of radio-detected and radio-undetected sources show different trends as a function of the theoretically predicted disk temperature.

  17. The optical emission line spectrum of Mark 110

    NASA Astrophysics Data System (ADS)

    Véron-Cetty, M.-P.; Véron, P.; Joly, M.; Kollatschny, W.

    2007-11-01

    Aims:We analyse in detail the rich emission line spectrum of Mark 110 to determine the physical conditions in the nucleus of this object, a peculiar NLS1 without any detectable Fe II emission associated with the broad line region and with a λ5007/Hβ line ratio unusually large for a NLS1. Methods: We use 24 spectra obtained with the Marcario Low Resolution Spectrograph attached at the prime focus of the 9.2 m Hobby-Eberly telescope at the McDonald observatory. We fitted the spectrum by identifying all the emission lines (about 220) detected in the wavelength range 4200-6900 Å (at rest). Results: The narrow emission lines are probably produced in a region with a density gradient in the range 103-106 cm-3 with a rather high column density (5×1021 cm-2). In addition to a narrow line system, three major broad line systems with different line velocity and width are required. We confirm the absence of broad Fe II emission lines. We speculate that Mark 110 is in fact a BLS1 with relatively “narrow” broad lines but with a BH mass large enough compared to its luminosity to have a lower than Eddington luminosity. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen. Table A.1 is only available in electronic form at http://www.aanda.org

  18. XMM study of the emission lines of the Z-Source GX 349+2

    NASA Astrophysics Data System (ADS)

    Iaria, Rosario

    2006-10-01

    We propose a 40 ks XMM observation of the Z source GX 349+2, to perform a detailed study of the iron K-shell features and other low energy features in this source. In particular this source is known to show a broad (0.7 keV FWHM) iron K_a line: several hypothesis were proposed to explain the width of these lines (relativistic and Doppler effects in an accretion disk, Compton scattering, line-blending), and we expect that the good energy resolution of XMM will be able to resolve the complex line shape and to constrain the various models proposed. Furthermore, since some emission lines were already observed in GX 349+2 with BeppoSAX below 3 keV, a proper study of these low energy features are an important diagnostic tool for the physical conditions of the emitting regions.

  19. Helium shells and faint emission lines from slitless flash spectra.

    PubMed

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence. PMID:25685435

  20. Helium shells and faint emission lines from slitless flash spectra

    NASA Astrophysics Data System (ADS)

    Bazin, Cyril; Koutchmy, Serge

    2013-05-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence.

  1. Helium shells and faint emission lines from slitless flash spectra

    PubMed Central

    Bazin, Cyril; Koutchmy, Serge

    2013-01-01

    At the time of the two last solar total eclipses of August 1st, 2008 in Siberia and July 11th, 2010 in French Polynesia, high frame rate CCD flash spectra were obtained. These eclipses occurred in quiet Sun period and after. The slitless flash spectra show two helium shells, in the weak Paschen α 4686 Å line of the ionized helium HeII and in the neutral helium HeI line at 4713 Å. The extensions of these helium shells are typically 3 Mm. In prominences, the extension of the interface with the corona is much more extended. The observations and analysis of these lines can properly be done only in eclipse conditions, when the intensity threshold reaches the coronal level, and the parasitic scattered light is virtually zero. Under the layers of 1 Mm above the limb, many faint low FIP lines were also seen in emission. These emission lines are superposed on the continuum containing absorption lines. The solar limb can be defined using the weak continuum appearing between the emission lines at the time of the second and third contact. The variations of the singly ionized iron line, the HeI and HeII lines and the continuum intensity are analyzed. The intensity ratio of ionized to neutral helium is studied for evaluating the ionization rate in low layers up to 2 Mm and also around a prominence. PMID:25685435

  2. Diagnostic beam absorber in Mu2e beam line

    SciTech Connect

    Rakhno, Igor; /Fermilab

    2011-03-01

    Star density, hadron flux, and residual dose distributions are calculated around the {mu}2e diagnostic beam absorber. Corresponding surface and ground water activation, and air activation are presented as well.

  3. Profiles of emission lines in Be stars.

    NASA Technical Reports Server (NTRS)

    Huang, S. S.

    1972-01-01

    Study of the broadening functions resulting from a gaseous ring in circular motion around a star according to Kepler's law. When the distribution in the gaseous ring has a circular symmetry in the equatorial plane, the broadening profile is related to the surface density distribution along the radius by an integral equation which can be transformed into the Abel integral equation and solved analytically. Profiles corresponding to gaseous rings with a uniform density distribution but different widths are used to illustrate the general properties of the profile broadened by the gaseous ring in circular motion. The emission profile has also been studied for cases in which the circular motion does not follow Kepler's law.

  4. Comparative electron temperature measurements of Thomson scattering and electron cyclotron emission diagnostics in TCABR plasmas

    SciTech Connect

    Alonso, M. P.; Figueiredo, A. C. A.; Berni, L. A.; Machida, M.

    2010-10-15

    We present the first simultaneous measurements of the Thomson scattering and electron cyclotron emission radiometer diagnostics performed at TCABR tokamak with Alfven wave heating. The Thomson scattering diagnostic is an upgraded version of the one previously installed at the ISTTOK tokamak, while the electron cyclotron emission radiometer employs a heterodyne sweeping radiometer. For purely Ohmic discharges, the electron temperature measurements from both diagnostics are in good agreement. Additional Alfven wave heating does not affect the capability of the Thomson scattering diagnostic to measure the instantaneous electron temperature, whereas measurements from the electron cyclotron emission radiometer become underestimates of the actual temperature values.

  5. Forbidden line emission from highly ionized atoms in tokamak plasmas

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Bhatia, A. K.

    1982-01-01

    Considerable interest in the observation of forbidden spectral lines from highly ionized atoms in tokamak plasmas is related to the significance of such observations for plasma diagnostic applications. Atomic data for the elements Ti Cr, Mn, Fe, Ni, and Kr have been published by Feldman et al. (1980) and Bhatia et al. (1980). The present investigation is concerned with collisional excitation rate coefficients and radiative decay rates, which are interpolated for ions of elements between calcium, and krypton and for levels of the 2s2 2pk, 2s 2p(k+1), and 2p(k+2) configurations, and for the O I, N I, C I, B I, and Be I isoelectronic sequences. The provided interpolated atomic data can be employed to calculate level populations and relative line intensities for ions of the considered sequences, taking into account levels of the stated configurations. Important plasma diagnostic information provided by the forbidden lines includes the ion temperature

  6. Far-Infrared Line Emission from High Redshift Quasars

    NASA Technical Reports Server (NTRS)

    Benford, D. J.; Cox, P.; Hunter, T. R.; Malhotra, S.; Phillips, T. G.; Yun, M. S.

    2002-01-01

    Recent millimeter and submillimeter detections of line emission in high redshift objects have yielded new information and constraints on star formation at early epochs. Only CO transitions and atomic carbon transitions have been detected from these objects, yet bright far-infrared lines such as C+ at 158 microns and N+ at 205 microns should be fairly readily detectable when redshifted into a submillimeter atmospheric window. We have obtained upper limits for C+ emission &om two high redshift quasars, BR1202-0725 at z=4.69 and BRI1335-0415 at z=4.41. These limits show that the ratio of the C+ line luminosity to the total far-infrared luminosity is less than 0.0l%, ten times smaller than has been observed locally. Additionally, we have searched for emission in the N+ 205 micron line from the Cloverleaf quasar, H1413+117, and detected emission in CO J=7-6. The N+ emission is found to be below the amount predicted based on comparison to the only previous detection of this line, in the starburst galaxy M82.

  7. Package for Interactive Analysis of Line Emission

    NASA Technical Reports Server (NTRS)

    Kashyap, Vinay; Hunter, Paul (Technical Monitor)

    2005-01-01

    PINTofALE is an IDL based package to analyze high-resolution grating spectra. The first version was made available to the public on 3 February 2001. Since then we have carried out numerous changes and subsidiary releases. The current release is version 2.0 (released 6 Apr 2004), and we are preparing to release v2.1 within the next month. The changes include bug fixes, upgrades to handle higher versions of IDL and the CHIANTI database, enhancements in user-friendliness, handling of instrument response matrices, and the release of a Markov Chain Monte Carlo based DEM fitting routines. A detailed description of the package, together with fairly detailed documentation, example walk-throughs, and downloadable tar files, are available on-line from http://hea.harvard.edu/PINTofALE/ The website also lists papers that have used PINTofALE in their analysis.

  8. Quantifying correlations between galaxy emission lines and stellar continua

    NASA Astrophysics Data System (ADS)

    Beck, Róbert; Dobos, László; Yip, Ching-Wa; Szalay, Alexander S.; Csabai, István

    2016-03-01

    We analyse the correlations between continuum properties and emission line equivalent widths of star-forming and active galaxies from the Sloan Digital Sky Survey. Since upcoming large sky surveys will make broad-band observations only, including strong emission lines into theoretical modelling of spectra will be essential to estimate physical properties of photometric galaxies. We show that emission line equivalent widths can be fairly well reconstructed from the stellar continuum using local multiple linear regression in the continuum principal component analysis (PCA) space. Line reconstruction is good for star-forming galaxies and reasonable for galaxies with active nuclei. We propose a practical method to combine stellar population synthesis models with empirical modelling of emission lines. The technique will help generate more accurate model spectra and mock catalogues of galaxies to fit observations of the new surveys. More accurate modelling of emission lines is also expected to improve template-based photometric redshift estimation methods. We also show that, by combining PCA coefficients from the pure continuum and the emission lines, automatic distinction between hosts of weak active galactic nuclei (AGNs) and quiescent star-forming galaxies can be made. The classification method is based on a training set consisting of high-confidence starburst galaxies and AGNs, and allows for the similar separation of active and star-forming galaxies as the empirical curve found by Kauffmann et al. We demonstrate the use of three important machine learning algorithms in the paper: k-nearest neighbour finding, k-means clustering and support vector machines.

  9. Emission lines in the optical spectrum of 3 Cen A

    NASA Astrophysics Data System (ADS)

    Wahlgren, G. M.; Hubrig, S.

    2004-05-01

    Previously, weak emission lines had been detected at red wavelengths in the spectra of a limited sample of mid to late B type main sequence stars. A fuller description of the occurrence and origins of these lines has yet to be forwarded, in part due to the lack of observations detailing the spectral transitions involved. To address this deficiency, we present a line list of weak emission features found in the optical and near infrared spectral region of the chemically peculiar He-weak star 3 Cen A (HD 120709). Nearly 350 features, mostly associated with allowed transitions from high-excitation states of first ions, are catalogued along with identifications. Prominent among the emission lines are the spectra P II, Mn II, Fe II, Ni II and Cu II. Emission lines from Ca II, Si II and Hg II are also evident. Abundances are determined for several elements from synthetic spectrum fitting, with anomalies detected for the ions O I/II, P II/III and Si II/III. The LTE synthetic spectrum fitting also revealed that the low excitation 4s-4p transitions of Fe II predict an abundance that is greater than that determined from higher excitation 4d-4f transitions. Several of these latter transitions have upper energy levels that are found to be associated with emission lines. We also present empirical considerations for the excitation processes leading to the weak emission lines. Based on observations obtained at the European Southern Observatory, La Silla, Chile, No. 65.L-0316 and Paranal, Chile No. 266.D-5655. Tables 2 and 3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/1073

  10. Line Emission from Radiation-pressurized H II Regions. II. Dynamics and Population Synthesis

    NASA Astrophysics Data System (ADS)

    Verdolini, Silvia; Yeh, Sherry C. C.; Krumholz, Mark R.; Matzner, Christopher D.; Tielens, Alexander G. G. M.

    2013-05-01

    Optical and infrared emission lines from H II regions are an important diagnostic used to study galaxies, but interpretation of these lines requires significant modeling of both the internal structure and dynamical evolution of the emitting regions. Most of the models in common use today assume that H II region dynamics are dominated by the expansion of stellar wind bubbles, and have neglected the contribution of radiation pressure to the dynamics, and in some cases also to the internal structure. However, recent observations of nearby galaxies suggest that neither assumption is justified, motivating us to revisit the question of how H II region line emission depends on the physics of winds and radiation pressure. In a companion paper we construct models of single H II regions including and excluding radiation pressure and winds, and in this paper we describe a population synthesis code that uses these models to simulate galactic collections of H II regions with varying physical parameters. We show that the choice of physical parameters has significant effects on galactic emission line ratios, and that in some cases the line ratios can exceed previously claimed theoretical limits. Our results suggest that the recently reported offset in line ratio values between high-redshift star-forming galaxies and those in the local universe may be partially explained by the presence of large numbers of radiation-pressure-dominated H II regions within them.

  11. Emission Line Assimetry in Active Galaxies: Mrk 533 and Mrk 110

    NASA Astrophysics Data System (ADS)

    Gavrilovic, N.

    2009-09-01

    In this work emission line asymmetries detected in two different types of Active Galactic Nuclei (AGN) - Seyfert 1 galaxy Mrk 110 and Seyfert 2 galaxy Mrk 533 were analyzed. Since emission lines in two galaxies arise in different emitting regions, detailed spectrum analysis gave the insight into kinematical properties of the Narrow Line and the Broad Line region (NLR and BLR) of this galaxies. We used several methods in the analysis procedure: (a) in order to analyse line profiles we performed profile decomposition into Gaussian components, (b) to study kinematical properties of the gas in the stellar disk, we used the model of "tilted-rings" (Begeman 1989), (c) to determine the sources of ionization of emitting region, we used the Veilleux and Osterbrock diagnostic diagram (Veilleux and Osterbrock 1987), (d) thermodynamical properties of the BLR were determined using the Boltzman plot method (Popović 2003). We showed that the red-shift and asymmetry of emission lines in Mrk 110 are probable caused by the strong gravitational field of the super massive black hole in the center of this galaxy. On the other hand, detailed analysis of 3D spectrophotometric observation of Mrk 533 made possible to map the outflow velocities from the very center of this galaxy, as well as shock waves in the circum-nuclear region, and to analyse the increase of the blue asymmetry with the increase of the outflow velocity (in more details see Smirnova et al. 2007).

  12. A study of diagnostic x-ray lines in heliumlike neon using an electron beam ion trap

    SciTech Connect

    Wargelin, B.J.

    1993-10-01

    Heliumlike ions play an extremely important role in X-ray astrophysics because of their emissivity and because the relative intensities of their emission lines can be used to infer physical characteristics of X-ray emitting plasmas, including temperature, electron density, and ionization balance. In order to properly apply these diagnostics, accurate atomic data are required, including cross sections for collisional excitation and ionization, radiative rates, and the wavelengths and strengths of satellite lines. Although theoretical atomic models have been created to estimate many of the rates and cross sections involved, very few experimental results are available for comparison with theoretical predictions. This thesis describes an experimental study of heliumlike neon using an electron beam ion trap, a device specifically designed to study X-ray emission from highly charged ions. Using a low-energy X-ray spectrometer designed and built for this experiment, electron impact excitation cross sections and dielectronic satellite strengths were measured for all significant n = 2{yields}1 emission lines in He-like and Li-like Ne over a range of energy extending from well below the direct excitation threshold of the lines to over fourteen times the threshold energy. The cross section for innershell ionization of Li-like Ne, which excites the He-like forbidden line, was also measured. In addition, the radiative and collisional depopulation rates of the metastable ls2s {sup 3}S{sub 1}, state, which form the basis of the He-like Ne density diagnostic, were determined. Experimental results were generally in agreement with theoretical predictions, although some significant differences were noted, particularly for the wavelengths and resonance strengths of dielectronic satellites.

  13. Near-Infrared Emission Lines of Nova Cassiopeiae 1995

    NASA Astrophysics Data System (ADS)

    Rudy, R. J.; Lynch, D. K.; Mazuk, S. M.; Venturini, C. C.; Puetter, R. C.

    2000-12-01

    The slow nova V 723 Cas (Nova Cas 1995) exhibits comparatively narrow emission features (FWHM 500 km sec-1) that make it ideal for classifying weak lines and lines blended with stronger features. We present spectra from 0.8-2.5 microns that track the gradual incrase in excitation of Nova Cas and discuss the emission lines that were present. During the period encompassed by these observations Nova Cas reached only moderate excitation-the most energetic coronal lines were [S VIII] 9913 and [Al IX] 20444; lines such as [S IX] 12523 that are prominent in some novae were not detected. Additional coronal lines present include [Si VI] 19641, [Ca VIII] 23205, and [Si VII] 24807. New lines identified include features of [Fe V], [Fe VI]. These iron features are not coronal lines, arising from transitions among low-lying terms rather than within the ground term itself. Also detected was [Ti VI] 17151 that was first identified in V1974 Cygni (Nova Cyg 1992), and possibly [Ti VII] 22050. Accurate wavelengths for a number of unidentified lines are also presented. These unidentified features are discussed with regard to their likely level of excitation and their presence in other novae. This work was supported by the IR&D program of the Aerospace Corporation. RCP acknowledges support from NASA.

  14. MICROLENSING OF QUASAR BROAD EMISSION LINES: CONSTRAINTS ON BROAD LINE REGION SIZE

    SciTech Connect

    Guerras, E.; Mediavilla, E.; Kochanek, C. S.; Munoz, J. A.; Falco, E.; Motta, V.

    2013-02-20

    We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8{sigma}), that high ionization lines such as C IV are more strongly microlensed than low ionization lines such as H{beta}, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region size of r{sub s} = 24{sup +22} {sub -15} and r{sub s} = 55{sup +150} {sub -35} lt-day (90% confidence) for the high and low ionization lines, respectively. When the samples are divided into higher and lower luminosity quasars, we find that the line emission regions of more luminous quasars are larger, with a slope consistent with the expected scaling from photoionization models. Our estimates also agree well with the results from local reveberation mapping studies.

  15. SED and Emission Line Properties of Red 2MASS AGN

    NASA Astrophysics Data System (ADS)

    Kuraszkiewicz, Joanna; Wilkes, Belinda J.; Schmidt, Gary; Ghosh, Himel

    2009-09-01

    Radio and far-IR surveys, and modeling of the cosmic X-ray background suggest that a large population of obscured AGN has been missed by traditional, optical surveys. The Two Micron All-Sky Survey (2MASS) has revealed a large population (surface density comparable to that of optically selected AGN with Ks<14.5mag) of mostly nearby (median z=0.25), red, moderately obscured AGN, among which 75% are previously unidentified emission-line AGN, with 85% showing broad emission lines. We present the SED and emission line properties of 44 such red (J-Ks>2) 2MASS AGN observed with Chandra. They lie at z<0.37, span a full range of spectral types (Type 1, intermediate, Type 2),Ks-to-X-ray slopes, and polarization (<13%). Their IR-to-X-ray spectral energy distributions (SEDs) are red in the near-IR/opt/UV showing little or no blue bump. The optical colors are affected by reddening, host galaxy emission, redshift, and in few, highly polarized objects, also by scattered AGN light. The levels of obscuration obtained from optical, X-rays, and far-IR imply N_H emission line equivalent widths, suggest a predominance of inclined objects in which obscuration/inclination allows us to see and study weaker emission components which are generally swamped by the direct AGN light. PCA analysis of the IR-X-ray SED and emission line properties shows that, while obscuration/inclination is important, the dominant cause of variance in the sample (eigenvector 1) is the L/L_{edd} ratio (perhaps because the red near-IR selection limits the range of inclination/obscuration values in our sample). This analysis also distinguishes two sources of obscuration: the host galaxy and circumnuclear absorption.

  16. 40 CFR 1033.110 - Emission diagnostics-general requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... equip your locomotives with a diagnostic system that will detect significant malfunctions in their... for in-use testing. Notify the owner/operator that the presence of this diagnostic system affects... engine operation. (d) Record and store in computer memory any diagnostic trouble codes showing...

  17. 40 CFR 1033.110 - Emission diagnostics-general requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... equip your locomotives with a diagnostic system that will detect significant malfunctions in their... for in-use testing. Notify the owner/operator that the presence of this diagnostic system affects... engine operation. (d) Record and store in computer memory any diagnostic trouble codes showing...

  18. KPC-Scale Properties of Emission-line Galaxies

    NASA Astrophysics Data System (ADS)

    Hemmati, Shoubaneh; Mobasher, Bahram; Candels

    2015-01-01

    We perform a detailed -combined spectroscopic and photometric- study of resolved properties of galaxies at kpc scale and investigate how small-scale and global properties of galaxies are related. The sample consists of 119 galaxies to z~1.3 with the unique feature of having very high-resolution spectroscopic data from long exposure observations with the KECK/DEIMOS. Using HST/ACS and WFC3 data taken as part of the CANDELS project, we produce resolved rest-frame (U-V) color, stellar mass and star formation surface densities, stellar age and extinction maps and profiles along the galaxies rotation axes. We model the optical nebular emission lines using the high-resolution DEIMOS spectra and construct the optical line ratio profiles diagnostic of metallicity (R23) and nebular extinction (Ha/Hb). We find that the nebular dust extinction profile, inferred from Balmer decrement, is in agreement with the average extinction derived from the resolved SED modeling. Using the R23 metallicity profiles we examine, for the first time, the mass metallicity relation across galaxies and explore how this relation changes as a function of spatial position. We identify red and blue 'regions' of statistical significance within individual galaxies, using their rest-frame color maps. As expected, for any given galaxy, the red regions are found to have higher stellar mass surface densities and older ages compared to the blue regions. Furthermore, we quantify the spatial distribution of red and blue regions with respect to both redshift and stellar mass, finding that the stronger concentration of red regions toward the centers of galaxies is not a significant function of either redshift or stellar mass. We find that the 'main sequence' of star forming galaxies exists among both red and blue regions inside galaxies, with the median of blue regions forming a tighter relation with a slope of 1.1±0.1 and a scatter of ˜ 0.2 dex compared to red regions with a slope of 1.3 ± 0.1 and a scatter

  19. Measurement of coronal X-ray emission lines from Capella

    NASA Technical Reports Server (NTRS)

    Vedder, P. W.; Canizares, C. R.

    1983-01-01

    The Einstein Observatory's Focal Plane Crystal Spectrometer has detected X-ray emission lines due to O VIII, Fe XVII, and Fe XX, from the binary star system Capella. Line luminosities are well fitted by an emitting plasma at a single temperature of 6.29 + or - 0.01 - 0.03 million K, and a volume emission measure of about 8.6 x 10 to the 52nd/cu cm, corresponding to the low temperature component previously observed. A high temperature component is undetectable, since the observed lines are not produced in plasma at temperatures above about 20 million K. Nearly isothermal plasma would be expected if many of the magnetically confined coronal loops have similar sizes and pressures, and a second population of longer loops would be required to account for the hotter component. An alternative interpretation of the observed X-ray line emission and upper limit is that the plasma contains a continuous distribution of emission measure versus temperature that rises sharply to 3 million K and then falls by nearly a decade to 16 million. An extrapolation of the loop sizes suggested by this alternative to hotter, longer loops may also account for the higher temperature emission.

  20. Impurity Line Emissions in VUV Region of TCABR Tokamak

    SciTech Connect

    Machida, M.; Daltrini, A. M.; Severo, J. H. F.; Nascimento, I. C.; Sanada, E. K.; Elizondo, J. I.; Kuznetsov, Y. K.; Galvao, R. M. O.

    2008-04-07

    Spectral emissions in the vacuum ultraviolet region from 50 nm to 320 nm have been measured on TCABR tokamak using an one meter VUV spectrometer and a MCP coupled to a CCD detector. Among the 98 emissions classified, 37 are from first order diffraction, 29 are from second order, 24 are from third order, 7 from fourth order, and one from fifth order diffraction. Main impurity lines are OII to OVII, CII to CIV, NIII to N V, FVII, besides working gas plasma hydrogen Lyman lines.

  1. The formation of emission lines in quasars and Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Kwan, J.; Krolik, J. H.

    1981-01-01

    The photoionization and heating throughout a quasar emission-line cloud optically thick at the Lyman edge are calculated. Photoionization and collisional ionization from excited states of hydrogen are included, which maintain a substantial electron fraction after the exhaustion of Lyman continuum photons halts ground-state photoionization. Observed values are explained for Ly-alpha/H-beta, H-alpha/H-beta, P-alpha/H-alpha, He I 5876/H-beta, O I 8446/H-alpha, and Mg II 2798/H-beta. The dependence of line strengths on physical conditions is discussed, and plotting Fe II/4570/H-beta versus Balmer continuum/H-beta is suggested. Other observations are also suggested, and the degree of asymmetry is given between the forward and backward emission of lines from a finite slab to make possible the use of comparative line profile studies to elucidate cloud kinematics.

  2. THE FORMATION OF IRIS DIAGNOSTICS. II. THE FORMATION OF THE Mg II h and k LINES IN THE SOLAR ATMOSPHERE

    SciTech Connect

    Leenaarts, J.; Pereira, T. M. D.; Carlsson, M.; De Pontieu, B.; Uitenbroek, H. E-mail: tiago.pereira@astro.uio.no E-mail: bdp@lmsal.com

    2013-08-01

    NASA's Interface Region Imaging Spectrograph (IRIS) small explorer mission will study how the solar atmosphere is energized. IRIS contains an imaging spectrograph that covers the Mg II h and k lines as well as a slit-jaw imager centered at Mg II k. Understanding the observations requires forward modeling of Mg II h and k line formation from three-dimensional (3D) radiation-magnetohydrodynamic (RMHD) models. This paper is the second in a series where we undertake this modeling. We compute the vertically emergent h and k intensity from a snapshot of a dynamic 3D RMHD model of the solar atmosphere, and investigate which diagnostic information about the atmosphere is contained in the synthetic line profiles. We find that the Doppler shift of the central line depression correlates strongly with the vertical velocity at optical depth unity, which is typically located less than 200 km below the transition region (TR). By combining the Doppler shifts of the h and k lines we can retrieve the sign of the velocity gradient just below the TR. The intensity in the central line depression is anti-correlated with the formation height, especially in subfields of a few square Mm. This intensity could thus be used to measure the spatial variation of the height of the TR. The intensity in the line-core emission peaks correlates with the temperature at its formation height, especially for strong emission peaks. The peaks can thus be exploited as a temperature diagnostic. The wavelength difference between the blue and red peaks provides a diagnostic of the velocity gradients in the upper chromosphere. The intensity ratio of the blue and red peaks correlates strongly with the average velocity in the upper chromosphere. We conclude that the Mg II h and k lines are excellent probes of the very upper chromosphere just below the TR, a height regime that is impossible to probe with other spectral lines. They also provide decent temperature and velocity diagnostics of the middle chromosphere.

  3. UV resonance line dayglow emissions on earth and Jupiter

    NASA Technical Reports Server (NTRS)

    Gladstone, G. Randall

    1988-01-01

    The similarities and differnces between atomic resonance line emissions on earth and Jupiter are studied. For earth, the scattering of the conservative atomic oxygen triplet transition at 1304 A and the nonconservative atomic oxygen sextuplet at 989 A is considered. For Jupiter, the scattering of the conservative atomic hydrogen doublet at 1216 A and the nonconservative atomic hydrogen doublet at 1026 A are addressed. Models are presented for the intensities of the emission features as seen from a distance of several planetary radii, using the same observational geometry for both earth and Jupiter. Variations of the line-integrated emissions across the disk and near the limb of each planet are examined in detail. Line profiles for the emission near the limb and at disk-center are also studied. The models reveal the importance of including inhomogeneities and temperature variations of the atmosphere in scattering models, and indicate that outer planet emissions previously interpreted as 'electroglow' may be solely due to resonant scattering of solar emissions.

  4. Carbon recombination lines as a diagnostic of photodissociation regions

    NASA Technical Reports Server (NTRS)

    Natta, A.; Walmsley, C. M.; Tielens, A. G. G. M.

    1994-01-01

    We have observed the C91 alpha radio recombination line toward the Orion H II region. This narrow (approximately 3-5 km per sec full width at half maximum (FWHM)) line is spatially very extended (approximately 8 arcmin or 1 pc). These charateristics compare well with the observed characteristics of the C II fine structure line at 158 microns. Thus, the C91 alpha line originates in the predominantly neutral photodissociation regions separating the H II region from the molecular cloud. We have developed theoretical models for the C II radio recombination lines from photodissociation regions. The results show that the I(C91 alpha)/I(C158) intensity ratio is a sensitive function of the temperature and density of the emitting gas. We have also extended theoretical models for photodissociation regions to include the C II recombination lines. Comparison with these models show that, in the central portion of the Orion region, the C91 alpha line originates in dense (10(exp 6) per cu cm), warm (500-1000 K) gas. Even at large projected distances (approximately 1 pc), the inferred density is still high (10(exp 5) per cu cm) and implies extremely high thermal pressures. As in the case of the (C II) 158 microns line, the large extent of the C91 alpha line shows that (FUV) photons can penetrate to large distances from the illuminating source. The decline of the intensity of the incident radiation field with distance from Theta(sup 1) C seems to be dominated by geometrical dilution, rather than dust extinction. Finally, we have used our models to calculate the intensity of the 9850 A recombination line of C II. The physical conditions inferred from this line are in good agreement with those determined from the radio recombination and the far-infrared fine-structure lines. We show that the ratio of the 9850 A to the C91 alpha lines is a very good probe of very high density clumps.

  5. Emission lines of [K v] in the optical spectra of gaseous nebulae

    PubMed Central

    Keenan, Francis P.; Aller, Lawrence H.; Espey, Brian R.; Exter, Katrina M.; Hyung, Siek; Keenan, Michael T. C.; Pollacco, Don L.; Ryans, Robert S. I.

    2002-01-01

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 Å)/I(4163.3 Å) as a function of electron density (Ne). This ratio is found to be very sensitive to changes in Ne over the density range 103 to 106 cm−3, but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical Ne diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo–Australian Telescope, reveals that the [K v] 4122.6 Å line in this object is badly blended with Fe ii 4122.6 Å. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum. PMID:11904366

  6. Emission lines of [K V] in the optical spectra of gaseous nebulae.

    PubMed

    Keenan, Francis P; Aller, Lawrence H; Espey, Brian R; Exter, Katrina M; Hyung, Siek; Keenan, Michael T C; Pollacco, Don L; Ryans, Robert S I

    2002-04-01

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 A)/I(4163.3 A) as a function of electron density (N(e)). This ratio is found to be very sensitive to changes in N(e) over the density range 10(3) to 10(6) cm(-3), but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical N(e) diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope, reveals that the [K v] 4122.6 A line in this object is badly blended with Fe ii 4122.6 A. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum. PMID:11904366

  7. Spectropolarimetry of the molecular hydrogen line emission from OMC-1

    NASA Technical Reports Server (NTRS)

    Burton, Michael G.; Hough, J. H.; Axon, David J.; Hasegawa, T.; Tamura, M.

    1988-01-01

    Observations of the H2 v = 1-0 S(1) line at 35 km/s velocity resolution were obtained at several locations within OMC-1, including the molecular hydrogen reflection nebula. All line profiles are smooth and show no evidence for being composed of discrete components. The data are discussed with respect to a model for the H2 line formation in which the emission originates in discrete clumps moving at different velocities. It is suggested that the extended blue wing may come from fast-moving clumps embedded in a wind.

  8. The Subaru FMOS galaxy redshift survey (FastSound). II. The emission line catalog and properties of emission line galaxies

    NASA Astrophysics Data System (ADS)

    Okada, Hiroyuki; Totani, Tomonori; Tonegawa, Motonari; Akiyama, Masayuki; Dalton, Gavin; Glazebrook, Karl; Iwamuro, Fumihide; Ohta, Kouji; Takato, Naruhisa; Tamura, Naoyuki; Yabe, Kiyoto; Bunker, Andrew J.; Goto, Tomotsugu; Hikage, Chiaki; Ishikawa, Takashi; Okumura, Teppei; Shimizu, Ikkoh

    2016-06-01

    We present basic properties of ˜3300 emission line galaxies detected by the FastSound survey, which are mostly Hα emitters at z ˜ 1.2-1.5 in the total area of about 20 deg2, with the Hα flux sensitivity limit of ˜1.6 × 10-16 erg cm-2 s-1 at 4.5 σ. This paper presents the catalog of the FastSound emission lines and galaxies, which is open to the public. We also present basic properties of typical FastSound Hα emitters, which have Hα luminosities of 1041.8-1043.3 erg s-1, star formation rates (SFRs) of 20-500 M⊙ yr-1, and stellar masses of 1010.0-1011.3 M⊙. The 3D distribution maps for the four fields of Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) W1-4 are presented, clearly showing large scale clustering of galaxies at the scale of ˜100-600 comoving Mpc. Based on 1105 galaxies with detections of multiple emission lines, we estimate that the contamination of non-Hα lines is about 4% in the single-line emission galaxies, which is mostly [O III]λ5007. This contamination fraction is also confirmed by the stacked spectrum of all the FastSound spectra, in which Hα, [N II]λλ6548,6583, [S II]λλ6717,6731, and [O I]λλ6300,6364 are seen.

  9. EQUIB: Atomic level populations and line emissivities calculator

    NASA Astrophysics Data System (ADS)

    Howarth, I. D.; Adams, S.; Clegg, R. E. S.; Ruffle, D. P.; Liu, X.-W.; Pritchet, C. J.; Ercolano, B.

    2016-03-01

    The Fortran program EQUIB solves the statistical equilibrium equation for each ion and yields atomic level populations and line emissivities for given physical conditions, namely electron temperature and electron density, appropriate to the zones in an ionized nebula where the ions are expected to exist.

  10. Infrared emission-line spectrum of Gamma Cassiopeiae

    SciTech Connect

    Hamann, F.; Simon, M.

    1987-07-01

    The near-IR spectrum of Gamma Cas contains emission lines of H I, He I, and Mg II. No lines of low-excitation species, such as are found in cool and dense environments, are detected. At the time of the observations,the observed Br-alpha and Br-gamma profiles were double-peaked, with V/R roughly 0.5 and FWHM roughly 260 km/s. The Br-gamma line profile varied significantly over the 4.5 month interval between the observations and those published by Chabaev and Maillard in 1985. The IR hydrogen line fluxes indicate that these lines are formed in a small, dense, optically thick region where the density of ionized gas declines sharply with distance from the star. Both the line profiles and fluxes are shown to be inconsistent with the predictions of standard stellar wind theory, but are in qualitative agreement with a rotating disk model such as was proposed in 1978 by Poeckert and Marlborough. The observations are discussed briefly in terms of their similarities and differences with the IR emission-line spectra of luminous young stellar objects. 40 references.

  11. The infrared emission-line spectrum of Gamma Cassiopeiae

    NASA Astrophysics Data System (ADS)

    Hamann, F.; Simon, M.

    1987-07-01

    The near-IR spectrum of Gamma Cas contains emission lines of H I, He I, and Mg II. No lines of low-excitation species, such as are found in cool and dense environments, are detected. At the time of the observations,the observed Br-alpha and Br-gamma profiles were double-peaked, with V/R roughly 0.5 and FWHM roughly 260 km/s. The Br-gamma line profile varied significantly over the 4.5 month interval between the observations and those published by Chabaev and Maillard in 1985. The IR hydrogen line fluxes indicate that these lines are formed in a small, dense, optically thick region where the density of ionized gas declines sharply with distance from the star. Both the line profiles and fluxes are shown to be inconsistent with the predictions of standard stellar wind theory, but are in qualitative agreement with a rotating disk model such as was proposed in 1978 by Poeckert and Marlborough. The observations are discussed briefly in terms of their similarities and differences with the IR emission-line spectra of luminous young stellar objects.

  12. Ethylene line emission from the North Pole of Jupiter

    NASA Technical Reports Server (NTRS)

    Kostiuk, Theodor; Espenak, F.; Romani, P.; Goldstein, J.

    1991-01-01

    A significant enhancement in infrared emission from hydrocarbon constituents of Jupiter's stratosphere was observed at a north polar hot spot (60 degrees latitude, 180 degrees longitude). A unique probe of this phenomena is ethylene (C2H4), which has not been observed previously from the ground. The profile of the emission line from ethylene at 951.742 cm-1, measured near the north pole of Jupiter, was analyzed to determine the morphology of the enhancement, the increase in C2H4 abundance and local temperature, as well as possible information on the altitude (pressure regions) where the increased emission is formed. Measurements were made using infrared heterodyne spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii in December 1989. At 181 degrees longitude a very strong emission line was seen, which corresponds to a 13-fold increase in C2H4 abundance or a 115K increase in temperature in the upper stratosphere, compared to values outside the hot spot. The hot spot was found to be localized to approx. 10 degrees in longitude; the line shape (width) implied that the enhanced emission originated very high in the stratosphere.

  13. A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes.

    PubMed

    Oosterbeek, J W; Bürger, A; Westerhof, E; de Baar, M R; van den Berg, M A; Bongers, W A; Graswinckel, M F; Hennen, B A; Kruijt, O G; Thoen, J; Heidinger, R; Korsholm, S B; Leipold, F; Nielsen, S K

    2008-09-01

    An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the diagnostic and, in particular, a sufficient suppression of the gyrotron component preventing it from interfering with ECE measurements. When integrated into a feedback system for the control of plasma instabilities this line-of-sight ECE diagnostic removes the need to localize the instabilities in absolute coordinates. PMID:19044409

  14. Searching for gas emission lines in Spitzer Infrared Spectrograph (IRS) spectra of young stars in Taurus

    NASA Astrophysics Data System (ADS)

    Baldovin-Saavedra, C.; Audard, M.; Güdel, M.; Rebull, L. M.; Padgett, D. L.; Skinner, S. L.; Carmona, A.; Glauser, A. M.; Fajardo-Acosta, S. B.

    2011-04-01

    Context. Our knowledge of circumstellar disks has traditionally been based on studies of dust. However, gas dominates the disk mass and its study is key to our understanding of accretion, outflows, and ultimately planet formation. The Spitzer Space Telescope provides access to gas emission lines in the mid-infrared, providing crucial new diagnostics of the physical conditions in accretion disks and outflows. Aims: We seek to identify gas emission lines in mid-infrared spectra of 64 pre-main-sequence stars in Taurus. Using line luminosities and other known star-disk-outflow parameters, we aim to identify correlations that will help to constrain gas heating, excitation mechanisms, and the line formation. Methods: We have based our study on Spitzer observations using the Infrared Spectrograph (IRS), mainly with the high-resolution modules. Line luminosities (or 3σ upper limits) have been obtained by fitting Gaussian profiles to the lines. We have further searched for correlations between the line luminosities and different parameters related to the star-disk system. Results: We have detected H2 (17.03, 28.22 μm) emission in 6 objects, [Ne II] (12.81 μm) emission in 18 objects, and [Fe II] (17.93, 25.99 μm) emission in 7 objects. [Ne II] detections are found primarily in Class II objects. The luminosity of the [Ne II] line (LNeII) is in general higher for objects known to drive jets than for those without known jets, but the two groups are not statistically distinguishable. LNeII is correlated with X-ray luminosity, but for Class II objects only. LNeII is also correlated with disk mass and accretion rate when the sample is divided into high and low accretors. Furthermore, we find correlations of LNeII with mid-IR continuum luminosity and with luminosity of the [O I] (6300 Å) line, the latter being an outflow tracer. L [FeII] correlates with Ṁacc. No correlations were found between LH2 and several tested parameters. Conclusions: Our study reveals a general trend

  15. Model for the intense molecular line emission from OMC-1

    SciTech Connect

    Draine, B.T.; Roberge, W.G.

    1982-08-15

    We present a model which attributes the observed H/sub 2/ and CO line emission OMC-1 to a magnetohydrodynamic shock propagating into magnetized molecular gas. By requiring the shock to reporoduce the observed line intensities, we determine the shock speed to be v/sub s/roughly-equal38 km s/sup -1/ and the preshock density and (transverse) magnetic field to be n/sub H/roughly-equal7 x 10/sup 5/ cm/sup -3/, B/sub O/roughly-equal1.5 milligauss. The model is compared to observations of H/sub 2/, CO, OH, O I, and C I in emission and of CO in absorption. The shock gas may be detectible in H I 21 cm emission.

  16. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1977-01-01

    The most important types of auroral radio emissions are reviewed, both from a historical perspective as well as considering the latest results. Particular emphasis is placed on four types of electromagnetic emissions which are directly associated with the plasma on the auroral field lines. These emissions are (1) auroral hiss, (2) saucers, (3) ELF noise bands, and (4) auroral kilometric radiation. Ray tracing and radio direction finding measurements indicate that both the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances from about 2.5 to 5 R sub e. For the auroral hiss the favored mechanism appears to be amplified Cerenkov radiation. For the auroral kilometric radiation several mechanisms have been proposed, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  17. Nebular Line Emission in z 1 Spitzer Infrared-Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Krause, John; Papovich, C.; Finkelstein, S.; Willmer, C.; Egami, E.; Conselice, C.; Huang, J.; Koo, D.; Laird, E.; Le Floc'h, E.; Lotz, J.; Maia, M.; Marcillac, D.; Nandra, K.; Webb, T.; Weiner, B.

    2010-01-01

    We present near-infrared (IR) spectroscopic observations from the Multi-Object IR Camera and Spectrograph (MOIRCS) on the Subaru telescope of a sample of 21 IR-luminous galaxies in the approximate range 1 < z < 1.5. These galaxies were selected based on their Spitzer 24-micron flux densities (S(24 micron) > 0.1 mJy) and known spectroscopic redshifts from the All-Wavelength Extended Groth Strip International Survey (AEGIS). We measure rest-frame optical emission line fluxes for H-alpha and [NII], and also [OIII] and H-beta, where available. We use emission-line diagnostics to constrain the origin of the ionization in these objects: processes associated with star formation or AGN (including Seyferts and LINERs). The high-redshift galaxies in our sample have similar [NII] / H-alpha flux ratios compared to low-redshift (z 0.1) IR-luminous galaxies (Kim et al., 1995; Veilleux et al., 1995) for galaxies with implied IR luminosities of 11 < Log L(8-1000 micron) / L sol < 12. However, we find evidence that the IR-luminous galaxies in our sample with implied Log L(8-1000 micron) / L sol > 12 have lower [NII] / H-alpha ratios than low-redshift galaxies with comparable IR luminosity, implying the higher redshift IR-luminous galaxies may have a higher fraction of systems dominated by star formation. We also study the relation of our rest-frame optical emission-line diagnostics to other indicators of AGN activity, including the mid-IR colors and X-ray luminosities. In addition, we compare star-formation-rate indicators from our dust-corrected H-alpha emission line luminosities to those from the mid-to-far IR and compare these as a function of IR luminosity against the low-redshift sample.

  18. Laboratory Study of the Diagnostic Utility of the 3C/3D Line Ratio in Fe XVII

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Beiersdorfer, P.; Chen, H.; Chen, M., II; Reed, K. J.

    2002-01-01

    Fe XVII X-ray emission is present in a multitude of sources, such as the corona of the Sun, Capella, and Procyon. Two of the strongest lines observed in these spectra are the resonance and intercombination lines located at 15.01 and 15.26 A, respectively. As part of the laboratory astrophysics program at the electron beam ion traps EBIT-I & EBIT-II located at the Lawrence Livermore National Laboratory we have measured this line ratio for the case where the relative abundance of Fe XVI to Fe XVII is approx. 1. Our results show that an Fe XVI innershell satellite line coincides with the intercombination line and can significantly reduce the relative intensity, R, of the resonance to intercombination line. The fact that the apparent relative intensity of the resonance and intercombination line in Fe XVII is sensitive to the strength of an Fe XVI innershell satellite, and therefore, tho relative abundance of Fe XVI to Fe XVII, makes the line ratio a diagnostic of temperature, and explains the anomalously low ratios observed in the solar and stellar coronae.

  19. Spectrophotometry of emission-line stars in the magellanic clouds

    NASA Technical Reports Server (NTRS)

    Bohannan, Bruce

    1990-01-01

    The strong emission lines in the most luminous stars in the Magellanic Clouds indicate that these stars have such strong stellar winds that their photospheres are so masked that optical absorption lines do not provide an accurate measure of photospheric conditions. In the research funded by this grant, temperatures and gravities of emission-line stars both in the Large (LMC) and Small Magellanic Clouds (SMC) have been measured by fitting of continuum ultraviolet-optical fluxes observed with IUE with theoretical model atmospheres. Preliminary results from this work formed a major part of an invited review 'The Distribution of Types of Luminous Blue Variables'. Interpretation of the IUE observations obtained in this grant and archive data were also included in a talk at the First Boulder-Munich Hot Stars Workshop. Final results of these studies are now being completed for publication in refereed journals.

  20. INVESTIGATING THE RELIABILITY OF CORONAL EMISSION MEASURE DISTRIBUTION DIAGNOSTICS USING THREE-DIMENSIONAL RADIATIVE MAGNETOHYDRODYNAMIC SIMULATIONS

    SciTech Connect

    Testa, Paola; De Pontieu, Bart; Martinez-Sykora, Juan; Hansteen, Viggo; Carlsson, Mats

    2012-10-10

    Determining the temperature distribution of coronal plasmas can provide stringent constraints on coronal heating. Current observations with the Extreme ultraviolet Imaging Spectrograph (EIS) on board Hinode and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory provide diagnostics of the emission measure distribution (EMD) of the coronal plasma. Here we test the reliability of temperature diagnostics using three-dimensional radiative MHD simulations. We produce synthetic observables from the models and apply the Monte Carlo Markov chain EMD diagnostic. By comparing the derived EMDs with the 'true' distributions from the model, we assess the limitations of the diagnostics as a function of the plasma parameters and the signal-to-noise ratio of the data. We find that EMDs derived from EIS synthetic data reproduce some general characteristics of the true distributions, but usually show differences from the true EMDs that are much larger than the estimated uncertainties suggest, especially when structures with significantly different density overlap along the line of sight. When using AIA synthetic data the derived EMDs reproduce the true EMDs much less accurately, especially for broad EMDs. The differences between the two instruments are due to the: (1) smaller number of constraints provided by AIA data and (2) broad temperature response function of the AIA channels which provide looser constraints to the temperature distribution. Our results suggest that EMDs derived from current observatories may often show significant discrepancies from the true EMDs, rendering their interpretation fraught with uncertainty. These inherent limitations to the method should be carefully considered when using these distributions to constrain coronal heating.

  1. Cloudy 94 and Applications to Quasar Emission Line Regions

    NASA Technical Reports Server (NTRS)

    Ferland, Gary J.

    2000-01-01

    This review discusses the most recent developments of the plasma simulation code Cloudy and its application to the, emission-line regions of quasars. The longterm goal is to develop the tools needed to determine the chemical composition of the emitting gas and the luminosity of the central engine for any emission line source. Emission lines and the underlying thermal continuum are formed in plasmas that are far from thermodynamic equilibrium. Their thermal and ionization states are the result of a balance of a vast set of microphysical processes. Once produced, radiation must, propagate out of the (usually) optically thick source. No analytic solutions are possible, and recourse to numerical simulations is necessary. I am developing the large-scale plasma simulation code Cloudy as an investigative tool for this work, much as an observer might build a spectrometer. This review describes the current version of Cloudy, version 94. It describes improvements made since the, release of the previous version, C90. The major recent, application has been the development of the "Locally Optimally-Emitting Cloud" (LOC) model of AGN emission line regions. Powerful selection effects, introduced by the atomic physics and line formation process, permit individual lines to form most efficiently only near certain selected parameters. These selection effects, together with the presence of gas with a wide range of conditions, are enough to reproduce the spectrum of a typical quasar with little dependence on details. The spectrum actually carries little information to the identity of the emitters. I view this as a major step forward since it provides a method to handle accidental details at the source, so that we can concentrate on essential information such as the luminosity or chemical composition of the quasar.

  2. K alpha line emission during solar X-ray bursts

    NASA Technical Reports Server (NTRS)

    Phillips, K. J. H.; Neupert, W. M.

    1973-01-01

    Calculations of K alpha line emission from S, Ar, Ca and Fe are presented. It is reported that on the basis of data for hard X-ray bursts, the flux during most impulsive, non-thermal events is likely to be weak, though for a few strong bursts, a flux of approximately 100 photons/cm/s may be expected. The amount of S K alpha emission particularly is sensitively dependent on the value of the lower energy bound of the non-thermal electron distribution, offering a possible means of determining this. Thermal K alpha emission is only significant for Fe ions. The calculated thermal K alpha radiation is much less than that observed during an intense soft X-ray burst. It is concluded that a detailed temperature structure for the emission source is required in order to explain the discrepancy.

  3. Time-dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U

    DOE PAGESBeta

    Muñoz Burgos, J. M.; Barbui, T.; Schmitz, O.; Stutman, D.; Tritz, K.

    2016-07-11

    Helium line-ratios for electron temperature (Te) and density (ne) plasma diagnostic in the Scrape-Off-Layer (SOL) and Edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet 667.8 and 728.1 nm, and triplet 706.5 nm visible lines have been typically preferred. Time-dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnosticmore » to high temporal resolution characterization of plasmas. The analysis is done using synthetic emission modeling and diagnostic for low electron density NSTX SOL plasma conditions by several visible lines. Quasi-static equilibrium, and time-dependent models are employed to evaluate transient effects of the atomic population levels that may affect the derived electron temperatures and densities as the helium gas-puff penetrates the plasma. Ultimately, the analysis of a wider range of spectral lines will help to extend this powerful diagnostic to experiments where the wavelength range of the measured spectra may be constrained either by limitations of the spectrometer, or by other conflicting lines from different ions.« less

  4. The Survey of Lines in M31 (SLIM): Origin of [CII] Emission

    NASA Astrophysics Data System (ADS)

    Kapala, Maria; Sandstrom, K.; Groves, B.; Croxall, K. V.; Dalcanton, J.; Gordon, K. D.; Krause, O.; Kreckel, K.; Leroy, A. K.; Rix, H.; Schinnerer, E.; Walter, F.

    2014-01-01

    The [CII] 158 micron line is typically the brightest far-IR emission line from star-forming galaxies. To use this line as a tracer of star-formation and a diagnostic of ISM conditions, we must understand which phases of the ISM and what gas heating sources are contributing to it. As a massive, nearby galaxy, Andromeda is ideal for studying [CII] because we can resolve individual star-forming regions in the galaxy, but it is representative of more distant galaxies. To address the origins of [CII], we have assembled a unique set of observations including: [CII] 158 micron and [OI] 63 micron lines from Herschel PACS; fully sampled optical integral field spectroscopy from PPAK on the Calar Alto 3.5m, and Herschel dust continuum mapping from 70-500 microns. These observations span a range of conditions across Andromeda. We present first results on how [CII] correlates with the far-IR continuum on ~50 pc scales. In particular, we find that star-forming regions in M31 do not exhibit a "[CII] line deficit" even in regions where the dust is very warm. Using the optical line emission, we determine the fraction of [CII] emission spatially associated with star-forming regions. Our method implies a high fraction ~40-75% of [CII] emission is coming from diffuse regions. These diffuse regions appear to dominated by the UV interstellar radiation field, which we infer from the Pan-Chromatic Hubble Andromeda Treasury data to be dominated by B stars. Our results suggest that studies using [CII] to trace the massive star-formation rate must take into account the the contribution of older stellar populations in heating the ISM gas.

  5. Rotation and emission lines in stars and accretion disks

    NASA Technical Reports Server (NTRS)

    Horne, Keith; Saar, Steven H.

    1991-01-01

    In the accretion disks of quiescent dwarf novae, Doppler mapping studies reveal that Balmer emission lines increase sharply toward the center of the disk, with surface brightnesses scaling roughly as R exp -3/2 varies as Omega(Kep). Similarly, among chromospherically active stars the H-alpha and Ca II H and K emission cores are stronger in the more rapidly rotating stars, with surface brightnesses scaling again roughly as Omega(rot). Since in both cases the emission lines scale linearly with the rotation frequency, it is proposed that the mechanism powering the emission lines in quiescent accretion disks is the same as that in chromospherically active stars, namely, the emergence of magnetic flux generated by the action of a dynamo, and its interaction with the atmosphere. If this empirical connection between disks and stars is in fact due to magnetic dynamos, the range of rotation rates available for testing dynamo theories expands from a factor of 1000 to 10 to the 7th.

  6. A transmission line bridge for the diagnostics of plasma channels

    NASA Astrophysics Data System (ADS)

    Pechacek, R. E.; Raleigh, M.; Greig, J. R.; Dwyer, T.; Ehrlich, J.

    1984-03-01

    This paper describes a device for measuring the average electrical conductivity of a long, narrow, cylindrical plasma. Interest in plasmas of this shape originates from two areas of study: the study of electron beam propagation through neutral gas, and the study of long straight electrical discharges for use as a communication antenna. Propagation of an electron beam through a neutral gas produces an ionized channel whose properties and evolution are very important to the propagation of the beam itself. Long straight electrical discharges are created in a channel that is ionized by a pulsed laser beam focused with a long focal length lens, and the properties of the plasma in this channel are important to the propagation of the electrical discharge along with channel. The properties of these plasmas are inferred from changes in the transmission properties of a transmission line placed close to and parallel to the plasma. In this paper an analysis is made of the relation between the bridge output voltage and the conductivity of the perturbing plasma for the case in which the conductivity is very low. In this case all perturbations on the bridge parameters are small, and linear approximations are appropriate. The usefulness of the bridge, however, extends to plasma well above this low conductivity range, although a different set of approximations may be necessary to make the analysis of the experiment tractable. A transmission line bridge is a device for measuring very small changes in the properties of transmission lines.

  7. Phenomenology of Broad Emission Lines in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Sulentic, J. W.; Marziani, P.; Dultzin-Hacyan, D.

    Broad emission lines hold fundamental clues about the kinematics and structure of the central regions in AGN. In this article we review the most robust line profile properties and correlations emerging from the best data available. We identify fundamental differences between the profiles of radio-quiet and radio-loud sources as well as differences between the high- and low-ionization lines, especially in the radio-quiet majority of AGN. An Eigenvector 1 correlation space involving FWHM Hβ, W(FeIIopt)/W(Hβ), and the soft X-ray spectral index provides optimal discrimination between all principal AGN types (from narrow-line Seyfert 1 to radio galaxies). Both optical and radio continuum luminosities appear to be uncorrelated with the E1 parameters. We identify two populations of radio-quiet AGN: Population A sources (with FWHM(Hβ) <~ 4000 km s-1, generally strong FeII emission and a soft X-ray excess) show almost no parameter space overlap with radio-loud sources. Population B shows optical properties largely indistinguishable from radio-loud sources, including usually weak FeII emission, FWHM(Hβ) >~ 4000 km s-1 and lack of a soft X-ray excess. There is growing evidence that a fundamental parameter underlying Eigenvector 1 may be the luminosity-to-mass ratio of the active nucleus (L/M), with source orientation playing a concomitant role.

  8. Emission Line Profiles of Warped Disks in a Kerr Spacetime

    NASA Astrophysics Data System (ADS)

    Yang, X. L.; Wang, J. C.

    2013-11-01

    The computations of emission line profiles of a warped disk around a Kerr black hole are discussed in this paper, which can be divided into two parts. In the first part, the geodesic motion in a Kerr spacetime and its equations with integral forms are presented. The equations are solved with the Weierstrass' elliptic functions and integrals. Making use of the elliptic functions, the Boyer-Lindquist (B-L) coordinates and the affine parameter σ are expressed semi-analytically as the functions of the parameter p. Then a code named ynogk (Yunnan Observatory Geodesic Kerr) is introduced based on the above discussions to calculate the null geodesics fast in a Kerr spacetime. In the second part of the paper, as an application of ynogk, the emission line profiles of a warped disk are investigated in detail. Here the structure model of the disk is specified according to the results of Bardeen and Petterson in 1975, and the line profiles are computed with the ray-tracing method. Finally, the discussions and conclusions of the computing results are presented, which indicate that the line profiles are dependent mainly on the inclination and azimuthal angles of the observer and the index of emissivity, and have the three-horn even multiple-horn structures comparing to those of a standard thin accretion disk.

  9. THE TEMPERATURE DIAGNOSTIC PROPERTIES OF THE Mg I 457.1 nm LINE

    SciTech Connect

    Langangen, Oeystein; Carlsson, Mats

    2009-05-10

    We analyze the important formation processes for the Mg I 457.1 nm line. This line is an intercombination line and the source function is close to the local thermodynamic equilibrium (LTE) value. The strong coupling to the local temperature and the relatively high population of the lower level (the ground state of Mg I) makes this line an ideal candidate for temperature diagnostics in the lower chromosphere/temperature minimum region. Linking the temperature probed to an absolute physical height is nontrivial because of non-LTE (NLTE) ionization. We analyze the NLTE effects and find that photoionization from the lower energy levels together with cascading collisional recombination dominates the ionization balance. Taking properly into account the line blanketing in the UV is essential for obtaining the right photoionization rates. The identification of the main NLTE effects in the line allows us to construct a 'quintessential' model atom, ideal for computationally demanding tasks, e.g., full three-dimensional and/or time-dependent radiative transfer. Furthermore, we analyze the diagnostic potential to temperature of this line in solarlike atmospheres, by synthesizing the line from a series of parameterized atmospheric models. These models have been constructed with fixed effective temperature, but with a variable heat term in the energy equation to obtain a chromospheric temperature rise at different heights. We conclude that the line has a significant potential in the diagnostics of the lower chromosphere temperature structure, especially for cooler atmospheres, such as sunspots.

  10. Do the Line Widths of Coronal Emission Lines Increase with Height above the Limb?

    NASA Astrophysics Data System (ADS)

    Singh, Jagdev; Sakurai, Takashi; Ichimoto, Kiyoshi

    2006-03-01

    In our earlier studies we obtained off-the-limb spectroscopic observations in a number of forbidden emission lines ([Fe X-XIV]) to study the physical properties and their temporal variations in steady coronal structures. Short exposure times adopted in those observations permitted us to study the variation in line widths up to about 150" above the limb. With a view to investigating the variations in the parameters of coronal emission lines up to about 500", we made raster scans with exposure times that are longer than the earlier exposure times by a factor of about 10. We find that the FWHM of the [Fe XIV] 5303 Å line decreases up to 300''+/-50'' and then remains more or less the same up to 500", while that of the [Fe X] 6374 Å line increases up to about 250" and subsequently remains unchanged. The FWHMs of the [Fe XI] 7892 Å and [Fe XIII] 10747 Å lines show an intermediate behavior. Furthermore, the ratio of the FWHM of 6374 to 5303 Å increases from 0.93 at the limb to 1.18 at 200" above the limb. The nonvariability in the FWHM of emission lines after about 300" above the limb in steady coronal structures does not support the prevailing view that the nonthermal velocity increases with height due to either the coronal waves or the high-velocity solar wind. The present results indicate the inadequacy of the earlier coronal loop models. The observed variations in FWHM of the coronal emission lines with height above the limb can be explained by assuming the recent model of coronal loops proposed by Akiyama et al.

  11. Emission lines and shock waves in RR Lyrae stars

    NASA Astrophysics Data System (ADS)

    Gillet, D.; Fokin, A. B.

    2014-05-01

    Context. Emission lines observed in radially pulsating stars are thought to be produced by atoms de-exciting after being excited by a shock wave that is traveling into and then compressing, heating, and accelerating the atmospheric gas. Aims: With the help of recent observations, we examine the origin of all the different types of emission lines of hydrogen and helium that appear during a pulsation cycle. Methods: To analyze the physical origin of emission lines, we used the different models of atmospheric dynamics of RR Lyrae stars that have been calculated so far. Results: In contrast to a recent explanation, we propose that the redshifted emission component of Hα, which occurs near the pulsation phase 0.3, is produced by the main shock. In this case, the emission is the natural consequence of the large extension of the expanding atmosphere. Therefore, this (weak) emission should only be observed in RR Lyrae stars for which the main shock will propagate far enough from the photosphere. It appears as a P-Cygni type profile. We estimate the shock front velocity during the shock propagation in the atmosphere and show that it decreases by 40% when the Hα emitting-shock passes from the photospheric level to the upper atmosphere. The Hα P-Cygni profile observed in long-period Cepheids also seems to be caused by the main shock wave. Although to date He II has only been detected in some Blazhko stars, a comprehensive survey of RR Lyrae stars is necessary to confirm this trend, so we can say that the most intense shocks will only be observed in Blazhko stars. Conclusions: The development of a model of atmospheric pulsation that takes the effects of 2D and 3D convection into account, seems to be a necessary step to fully quantify the effects of shock waves on the atmospheric dynamics of radially pulsating stars.

  12. Plasma simulations of emission line regions in high energy environments

    NASA Astrophysics Data System (ADS)

    Richardson, Chris T.

    This dissertation focuses on understanding two different, but in each case extreme, astrophysical environments: the Crab Nebula and emission line galaxies. These relatively local objects are well constrained by observations and are test cases of phenomena seen at high-z where detailed observations are rare. The tool used to study these objects is the plasma simulation code known as Cloudy. The introduction provides a brief summary of relevant physical concepts in nebular astrophysics and presents the basic features and assumptions of Cloudy. The first object investigated with Cloudy, the Crab Nebula, is a nearby supernova remnant that previously has been subject to photoionization modeling to reproduce the ionized emission seen in the nebula's filamentary structure. However, there are still several unanswered questions: (1) What excites the H2 emitting gas? (2) How much mass is in the molecular component? (3) How did the H2 form? (4) What is nature of the dust grains? A large suite of observations including long slit optical and NIR spectra over ionized, neutral and molecular gas in addition to HST and NIR ground based images constrain a particularly bright region of H2 emission, Knot 51, which exhibits a high excitation temperature of ˜3000 K. Simulations of K51 revealed that only a trace amount of H2 is needed to reproduce the observed emission and that H2 forms through an uncommon nebular process known as associative detachment. The final chapters of this dissertation focus on interpreting the narrow line region (NLR) in low-z emission line galaxies selected by a novel technique known as mean field independent component analysis (MFICA). A mixture of starlight and radiation from an AGN excites the gas present in galaxies. MFICA separates galaxies over a wide range of ionization into subsets of pure AGN and pure star forming galaxies allowing simulations to reveal the properties responsible for their observed variation in ionization. Emission line ratios can

  13. Anisotropic alpha emission from on-line separated isotopes

    SciTech Connect

    Wouters, J.; Vandeplassche, D.; van Walle, E.; Severijns, N.; Vanneste, L.

    1986-05-05

    A systematic on-line nuclear-orientation study of heavy isotopes using anisotropic ..cap alpha.. emission is reported for the first time. The anisotrophies recorded for /sup 199/At, /sup 201/At, and /sup 203/At are remarkably pronounced and strongly varying. At lower neutron number the ..cap alpha.. particles are more preferentially emitted perpendicularly to the nuclear-spin direction. This may be interpreted in terms of the high sensitivity of the ..cap alpha..-emission probability to changes in the nuclear shape.

  14. Electromagnetic plasma wave emissions from the auroral field lines

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.

    1978-01-01

    The most important types of auroral radio emissions are reviewed. Particular attention is given to the following four types of electromagnetic emissions: auroral hiss, saucers, ELF noise bands, and auroral kilometric radiation. It is shown that the auroral hiss and auroral kilometric radiation are generated along the auroral field lines relatively close to the earth, at radial distances in the range of 2.5-5 earth radii, probably in direct association with auroral-particle acceleration by parallel electric fields. The auroral hiss appears to be generated by amplified Cerenkov radiation. Several mechanisms are proposed for the auroral kilometric radiation, usually involving the intermediate generation of electrostatic waves by the precipitating electrons.

  15. 40 CFR 1033.112 - Emission diagnostics for SCR systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diagnostic system must monitor reductant quality and tank levels and alert operators to the need to refill... computer memory all incidents of engine operation with inadequate reductant injection or reductant...

  16. 40 CFR 1033.112 - Emission diagnostics for SCR systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... diagnostic system must monitor reductant quality and tank levels and alert operators to the need to refill... computer memory all incidents of engine operation with inadequate reductant injection or reductant...

  17. TYPING SUPERNOVA REMNANTS USING X-RAY LINE EMISSION MORPHOLOGIES

    SciTech Connect

    Lopez, L. A.; Ramirez-Ruiz, E.; Badenes, C.; Huppenkothen, D.; Jeltema, T. E.

    2009-11-20

    We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in 17 Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse supernovae explosions are intrinsically more asymmetric.

  18. Emission line eclipse phenomena in nova DQ Herculis /1934/

    NASA Astrophysics Data System (ADS)

    Young, P.; Schneider, D. P.

    1980-06-01

    H-gamma, He II 4686 A, and H-beta emission lines were observed in DQ Her through an eclipse (phases 0.80-0.15). A total of 14 spectra with exposure times of 300 seconds were used to investigate phenomena in the eclispe of the emitting region by the red companion. The classical rotational disturbance of the He II 4686 A line is observed; it changes its velocity by over 600 km/s in 25 minutes during the eclipse. The eclipse duration is very long (0.11 of a cycle) and indicates a mass ratio near unity.

  19. K alpha line emission during solar X-ray bursts

    NASA Technical Reports Server (NTRS)

    Phillips, K. J. H.; Neupert, W. M.

    1973-01-01

    The expected flux of K alpha line emission from sulfur, argon, calcium, and iron is calculated during both thermal and nonthermal solar X-ray events. Such emission is shown to be weak during the course of most of the nonthermal hard X-ray bursts that Kane and Anderson (1970) have observed. If Compton backscattering is significant at high energies, the flux is reduced still further for disk flares, but it is noted that the strong, near-limb burst of June 26 would have produced about 100 photons /sq cm/sec of sulfur and iron K alpha emission. The impulsive hard X-ray bursts may in general be too short-lived for much K alpha emission. It may be noted that sulfur K alpha emission in particular depends sensitively on the lower-energy limit of the nonthermal electron spectrum, assuming such a sharply defined boundary exists. During soft X-ray bursts, when temperatures of a few 10 to the 7th power K are obtained, K alpha emission from certain iron ions, specifically Fe XVIII-XXIII, may be important.

  20. Low Luminosity Cataclysmic Variables and Fe Emission Lines of Galactic Ridge X-ray Emission

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojie; Wang, Q. Daniel

    2015-08-01

    Cataclysmic variables (CVs) has been proposed to be one of the main contributors of the Galactic Ridge X-ray Emission (GRXE). However, previous studies on the spectra of local CVs suggested that the I6.7keV/I7.0keV line intensity ratios of CVs are not consistent with that of GRXE. Utilizing the archival Suzaku observations on local CVs, we confirm that luminous local CVs like intermediate polars, symbiotic stars and polars have lower I6.7keV/I7.0keV values, thus are unable to explain the Fe emission line ratios of GRXE. On the other hand, dimmer CVs like dwarf novae (DNe) have I6.7keV/I7.0keV values consitent with that of GRXE. Given the potential huge population, DNe could be one of the main resources of GRXE Fe line emission.

  1. Accretion disk corona line emission from X0614+091

    NASA Technical Reports Server (NTRS)

    Christian, D. J.; White, N. E.; Swank, J. H.

    1994-01-01

    The low-mass X-ray binary X0614+091 was observed on 3 days in 1979 with the Einstein Observatory solid state spectrometer and the monitor proportional counter. During the observation with the highest measured flux, corresponding to an X-ray luminosity of 8 x 10(exp 36) erg/s (in the 0.5-20 keV band for an assumed distance of 5 kpc), significant low-energy emission was detected, centered at 0.77 keV, possibly due to line emission for O VII-O VIII and Fe XVII-Fe XIX. The other observations, which were at fluxes lower by a factor of 2, are consistent with the presence of the emission feature. The equivalent width of the feature, 37 +/- 6 eV, is of the same order as equivalent widths previously reported for more luminous low-mass X-ray binaries using grating spectrometer data. The soft X-ray lines could be emitted by gas expected to arise in an accretion disk corona excited by the central source. But to explain the observed feature, most of the corona needs to contribute, or other sources of emission are required.

  2. Shock-induced polarized hydrogen emission lines in omicron Ceti

    NASA Astrophysics Data System (ADS)

    Fabas, N.; Lèbre, A.; Gillet, D.

    2012-05-01

    Hydrogen emission lines in Mira variable stars are a well-known phenomenon whose origin has been established as related to the propagation of radiative hypersonic shock waves throughout the stellar atmosphere. A polarimetric observation by McLean and Coyne [1] made on omicron Ceti (the prototype of Mira variable stars) has revealed the existence of linear polarization signatures associated with Balmer emission lines. However, the polarizing mechanism has never been properly explained so far. The study presented here is the first of its kind since it displays the results of a spectropolarimetric survey of omicron Ceti in the Balmer lines. The survey was made with the NARVAL spectropolarimeter (Telescope Bernard Lyot, France) in full Stokes mode. We did not just confirm the appearance of this polarization but we also and above all showed the temporal variation of the linear polarization in the lines. We conclude that the polarizing mechanism is definitely intrinsic to the shock wave propagation throughout the stellar atmosphere of Mira and give some leads about the nature of this mechanism.

  3. Morphological processing of ultraviolet emissions of electrical corona discharge for analysis and diagnostic use.

    PubMed

    Schubert, Matthew; Moore, Andrew J

    2016-03-01

    Electron cascades from electrical discharge produce secondary emissions from atmospheric plasma in the ultraviolet band. For a single point of discharge, these emissions exhibit a stereotypical discharge morphology, with latent information about the discharge location. Morphological processing can uncover the location and therefore have diagnostic utility. PMID:26974615

  4. Morphological Processing of Ultraviolet Emissions of Electrical Corona Discharge for Analysis and Diagnostic Use

    NASA Technical Reports Server (NTRS)

    Schubert, Matthew R.; Moore, Andrew J.

    2015-01-01

    Electron cascades from electrical discharge produce secondary emissions from atmospheric plasma in the ultraviolet band. For a single point of discharge, these emissions exhibit a stereotypical discharge morphology, with latent information about the discharge location. Morphological processing can uncover the location and therefore can have diagnostic utility.

  5. Search for an emission line of a gravitational wave background

    NASA Astrophysics Data System (ADS)

    Nishizawa, Atsushi; Seto, Naoki

    2015-06-01

    In light of the history of research on an electromagnetic wave spectrum, a sharp emission line of gravitational wave background (GWB) would be an interesting observational target. Here we study an efficient method to detect a line GWB by correlating data of multiple ground-based detectors. We find that the width of frequency bin for coarse graining is a critical parameter, and, with the commonly used value 0.25 Hz, the signal-to-noise ratio could be decreased by up to a factor of 6.6, compared with a finer width of 0.02 Hz. By reanalyzing the existing data with a smaller bin width, we might detect a precious line signal from the early Universe.

  6. Continuum and line emission of flares on red dwarf stars

    NASA Astrophysics Data System (ADS)

    Morchenko, E.; Bychkov, K.; Livshits, M.

    2015-06-01

    The emission spectrum has been calculated of a homogeneous pure hydrogen layer, which parameters are typical for a flare on a red dwarf. The ionization and excitation states were determined by the solution of steady-state equations taking into account the continuum and all discrete hydrogen levels. We consider the following elementary processes: electron-impact transitions, spontaneous and induced radiative transitions, and ionization by the bremsstrahlung and recombination radiation of the layer itself. The Biberman-Holstein approximation was used to calculate the scattering of line radiation. Asymptotic formulae for the escape probability are obtained for a symmetric line profile taking into account the Stark and Doppler effects. The approximation for the core of the H- α line by a Gaussian curve has been substantiated.

  7. ESTIMATION OF RELATIVISTIC ACCRETION DISK PARAMETERS FROM IRON LINE EMISSION

    SciTech Connect

    V. PARIEV; B. BROMLEY; W. MILLER

    2001-03-01

    The observed iron K{alpha} fluorescence lines in Seyfert I galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the emission. Here we present an analysis of the geometrical and kinematic properties of the disk based on the extreme frequency shifts of a line profile as determined by measurable flux in both the red and blue wings. The edges of the line are insensitive to the distribution of the X-ray flux over the disk, and hence provide a robust alternative to profile fitting of disk parameters. Our approach yields new, strong bounds on the inclination angle of the disk and the location of the emitting region. We apply our method to interpret observational data from MCG-6-30-15 and find that the commonly assumed inclination 30{degree} for the accretion disk in MCG-6-30-15 is inconsistent with the position of the blue edge of the line at a 3{sigma} level. A thick turbulent disk model or the presence of highly ionized iron may reconcile the bounds on inclination from the line edges with the full line profile fits based on simple, geometrically thin disk models. The bounds on the innermost radius of disk emission indicate that the black hole in MCG-6-30-15 is rotating faster than 30% of theoretical maximum. When applied to data from NGC 4151, our method gives bounds on the inclination angle of the X-ray emitting inner disk of 50 {+-} 10{degree}, consistent with the presence of an ionization cone grazing the disk as proposed by Pedlar et al. (1993). The frequency extrema analysis also provides limits to the innermost disk radius in another Seyfert 1 galaxy, NGC 3516, and is suggestive of a thick disk model.

  8. Use of FUV auroral emissions as diagnostic indicators

    SciTech Connect

    Germany, G.A.; Torr, D.G.; Richards, P.G. ); Torr, M.R. )

    1994-01-01

    In an earlier study the authors modeled selected FUV auroral emissions (O I (1356 [angstrom]), N[sub 2] Lyman-Birge-Hopfield (LBH) (1464 [angstrom]), and LBH (1838 [angstrom])) to examine the sensitivity of these emissions and their ratios to likely changes in the neutral atmosphere. In this paper they extent that study to examine the dependence of these same emissions and their ratios on the shape of the energy distribution of the auroral electrons. In particular, they wish to determine whether changes in energy spectra might interfere with their determination of the characteristic energy. Modeled column-integrated emissions show relatively small (<30%) dependences on the shape and width of the incident energy spectrum, provided the average energy and total energy flux of the energy distribution are held constant. Long-wavelength FUV emissions, which are relatively unaffected by O[sub 2] absorption losses, exhibit virtually no dependence on the shape of the incident energy distribution. Changes in ratios of FUV short- to long-wavelength emissions as a function of characteristic energy are much larger than those due to changes in energy distribution. As a result, the determination of characteristic energy using these emission ratios is relatively unambiguous. They also examine the relative intensities of the aurora and the dayglow for various conditions. The intensities of modeled FUV auroral emissions relative to the dayglow emissions are presented as a function of solar zenith angle and incident energy flux. Under certain conditions (energy flux [le] 1 erg cm[sup [minus]2] s[sup [minus]1] and solar zenith angle [le]50[degrees]) the dayglow will be the limiting factor in the detection of weak auroras. 19 refs., 10 figs., 1 tab.

  9. The optically thick O III spectrum. I - Diagnostic ratios involving the intercombination lines

    NASA Technical Reports Server (NTRS)

    Kastner, S. O.; Bhatia, A. K.

    1989-01-01

    An escape-probability calculation of the optically thick O III spectrum is carried out to obtain the optical depth dependence of the intercombination doublet at 1663 A and of resonance lines between the 2p2, 2s2p3, and 2p4 configurations. The effect of optical depth on diagnostic ratios involving the intercombination lines is quantitatively established. The general question raised is whether such effects may occur in actual sources.

  10. A proposed new diagnostic for Herbig disc geometry. FWHM versus J of CO ro-vibrational lines

    NASA Astrophysics Data System (ADS)

    Hein Bertelsen, R. P.; Kamp, I.; van der Plas, G.; van den Ancker, M. E.; Waters, L. B. F. M.; Thi, W.-F.; Woitke, P.

    2016-05-01

    sources and their inner CO radius. Conclusions: The FWHM versus J is a potential new gas diagnostic for the inner disc with, for example, a constant FWHM versus J indicating the presence of a large gas hole or gap. Models and observations both indicate the potential of this new diagnostic. Our extended sample does not fully support the previous trend where group I discs have CO ro-vibrational emission lines with small FWHM. Instead, our CO ro-vibrational data from a handful of sources indicates different inner disc geometries for the gas and dust of these sources. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 088.C-0898A and programme ID 084.C-1002(A).

  11. Performance Assessment of the C-Mod Multi-Spectral Line Polarization MSE (MSE-MSLP) Diagnostic

    NASA Astrophysics Data System (ADS)

    Scott, Steven; Mumgaard, Robert; Khoury, Matthew

    2015-11-01

    The accuracy of the Alcator C-Mod Motional Stark Effect (MSE) diagnostic is limited primarily by partially polarized background light that varies rapidly both in time (1 ms) and space - factor 10 variations are observed between adjacent spatial channels. ITER is likely to operate in a similar regime. Visible Bremsstrahlung, divertor molecular D2 emission, and glowing invessel structures generate unpolarized light that becomes partially polarized upon reflection. Because all three sources are broadband, the background light can be measured in real-time at wavelengths close to the MSE spectrum, thereby allowing the background to be interpolated in wavelength rather than in time. A 10-spatial-channel, 4-wavelength MSE-MSLP system has been developed using polarization polychromators that measure simultaneously the MSE pi- and sigma- lines as well as two nearby wavelengths that were chosen to avoid both the MSE spectrum and all known impurity lines on each sightline. Initial performance evaluation indicates that the background channel measurements faithfully track the background light in the pi- and sigma- lines. The improvement in accuracy of pitch-angle measurements and increased diagnostic flexibility over a wide range of plasma conditions will be reported. This work is supported by USDoE awards DE-FC02-99ER54512 and DE-AC02-09CH11466.

  12. The nuclear region of low luminosity flat radio spectrum sources. II. Emission-line spectra

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. C.; Serote Roos, M.

    2004-01-01

    We report on the spectroscopic study of 19 low luminosity Flat Radio Spectrum (LL FRS) sources selected from Marchã's et al. (\\cite{March96}) 200 mJy sample. In the optical, these objects are mainly dominated by the host galaxy starlight. After correcting the data for this effect, we obtain a new set of spectra clearly displaying weak emission lines; such features carry valuable information concerning the excitation mechanisms at work in the nuclear regions of LL FRS sources. We have used a special routine to model the spectra and assess the intensities and velocities of the emission lines; we have analyzed the results in terms of diagnostic diagrams. Our analysis shows that 79% of the studied objects harbour a Low Ionization Nuclear Emission-line Region (or LINER) whose contribution was swamped by the host galaxy starlight. The remaining objects display a higher ionization spectrum, more typical of Seyferts; due to the poor quality of the spectra, it was not possible to identify any possible large Balmer components. The fact that we observe a LINER-type spectrum in LL FRS sources supports the idea that some of these objects could be undergoing an ADAF phase; in addition, such a low ionization emission-line spectrum is in agreement with the black hole mass values and sub-Eddington accretion rates published for some FRS sources. Based on observations collected at the Multiple Mirror Telescope on Mt. Hopkins. Full Fig. 1 is only available in electronic form at http://www.edpsciences.org

  13. Sodium D-line emission from Io - Comparison of observed and theoretical line profiles

    NASA Technical Reports Server (NTRS)

    Carlson, R. W.; Matson, D. L.; Johnson, T. V.; Bergstralh, J. T.

    1978-01-01

    High-resolution spectra of the D-line profiles have been obtained for Io's sodium emission cloud. These lines, which are produced through resonance scattering of sunlight, are broad and asymmetric and can be used to infer source and dynamical properties of the sodium cloud. In this paper we compare line profile data with theoretical line shapes computed for several assumed initial velocity distributions corresponding to various source mechanisms. We also examine the consequences of source distributions which are nonuniform over the surface of Io. It is found that the experimental data are compatible with escape of sodium atoms from the leading hemisphere of Io and with velocity distributions characteristic of sputtering processes. Thermal escape and simple models of plasma sweeping are found to be incompatible with the observations.

  14. EFFECTS OF AN ACCRETION DISK WIND ON THE PROFILE OF THE BALMER EMISSION LINES FROM ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Flohic, Helene M. L. G.; Eracleous, Michael; Bogdanovic, Tamara E-mail: mce@astro.psu.edu

    2012-07-10

    We explore the connection between active galactic nuclei (AGNs) with single- and double-peaked broad Balmer emission lines by using models dealing with radiative transfer effects through a disk wind. Our primary goal is to assess the applicability of the Murray and Chiang model by making an extensive and systematic comparison of the model predictions with data. In the process, we also verify the original derivation and evaluate the importance of general relativistic effects. As the optical depth through the emission layer increases, the peaks of a double-peaked profile move closer and eventually merge, producing a single peak. The properties of the emission line profile depend as sensitively on the geometric parameters of the line-emitting portion of the disk as they do on the disk-wind parameters. Using a parameter range that encompasses the expected characteristics of the broad-line regions in AGNs, we construct a database of model profiles and measure a set of diagnostic properties. Comparisons of the model profiles with emission lines from a subset of Sloan digital Sky Survey quasars show that observed lines are consistent with moderately large optical depth in the disk wind and a range of disk inclinations i {approx}< 45 Degree-Sign . Including relativistic effects is necessary to produce the asymmetries of observed line profiles.

  15. Infrared coronal emission lines and the possibility of their maser emission in Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew A.; Feldman, Uri; Smith, Howard A.; Klapisch, Marcel; Bhatia, Anand K.; Bar-Shalom, Abi

    1993-01-01

    Energetic emitting regions have traditionally been studied via x-ray, UV and optical emission lines of highly ionized intermediate mass elements. Such lines are often referred to as 'coronal lines' since the ions, when produced by collisional ionization, reach maximum abundance at electron temperatures of approx. 10(exp 5) - 10(exp 6) K typical of the sun's upper atmosphere. However, optical and UV coronal lines are also observed in a wide variety of Galactic and extragalactic sources including the Galactic interstellar medium, nova shells, supernova remnants, galaxies and QSOs. Infrared coronal lines are providing a new window for observation of energetic emitting regions in heavily dust obscured sources such as infrared bright merging galaxies and Seyfert nuclei and new opportunities for model constraints on physical conditions in these sources. Unlike their UV and optical counterparts, infrared coronal lines can be primary coolants of collisionally ionized plasmas with 10(exp 4) less than T(sub e)(K) less than 10(exp 6) which produce little or no optical or shorter wavelength coronal line emission. In addition, they provide a means to probe heavily dust obscured emitting regions which are often inaccessible to optical or UV line studies. In this poster, we provide results from new model calculations to support upcoming Infrared Space Observatory (ISO) and current ground-based observing programs involving infrared coronal emission lines in AGN. We present a complete list of infrared (lambda greater than 1 micron) lines due to transitions within the ground configurations 2s(2)2p(k) and 3s(2)3p(k) (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (x greater than or equal to 100 eV) astrophysically abundant (n(X)/n(H) greater than or equal to 10(exp -6)) elements. Included are approximately 74 lines in ions of O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni spanning a wavelength range of approximately 1 - 280 microns. We present new

  16. CO line emission from shock waves in molecular clouds

    SciTech Connect

    Draine, B.T.; Roberge, W.G.

    1984-07-15

    Calculations are presented of the emission spectrum of rotationally and vibrationally excited carbon monoxide in shocked interstellar molecular clouds. The calculations are based upon hydrodynamical shock models that include the effects of magnetically driven ion-neutral streaming. They incorporate a variety of collision processes that produce excited CO molecules, including H/sub 2/--CO collisions. The effects of photon trapping on the emission and excitation are included by means of a Sobolev-like approximation. Intensities are given for lines emitted from levels with J< or =60, for C-type shocks with speeds v/sub s/ from 5 to 50 km s/sup -1/, in clouds with densities n/sub H/ between 10/sup 2/ and 10/sup 6/ H nuclei per cm/sup 3/. Population inversions are found amongst the lowest levels of CO for a range of shock speeds and preshock conditions. Maser emission may be observable in favorable cases. Emission from vibrationally excited levels of CO may be detectable from v/sub s/> or approx. =35 km s/sup -1/ shocks in n/sub d/H = 10/sup 6/ cm/sup -3/ clouds.

  17. Hybrid time dependent/independent solution for the He I line ratio temperature and density diagnostic for a thermal helium beam with applications in the scrape-off layer-edge regions in tokamaks

    SciTech Connect

    Munoz Burgos, J. M.; Schmitz, O.; Loch, S. D.; Ballance, C. P.

    2012-01-15

    Spectroscopic studies of line emission intensities and ratios offer an attractive option in the development of non-invasive plasma diagnostics. Evaluating ratios of selected He I line emission profiles from the singlet and triplet neutral helium spin systems allows for simultaneous measurement of electron density (n{sub e}) and temperature (T{sub e}) profiles. Typically, this powerful diagnostic tool is limited by the relatively long relaxation times of the {sup 3}S metastable term of helium that populates the triplet spin system, and on which electron temperature sensitive lines are based. By developing a time dependent analytical solution, we model the time evolution of the two spin systems. We present a hybrid time dependent/independent line ratio solution that improves the range of application of this diagnostic technique in the scrape-off layer (SOL) and edge plasma regions when comparing it against the current equilibrium line ratio helium model used at TEXTOR.

  18. Emission-line objects projected upon the galactic bulge.

    PubMed

    Herbig, G H

    1969-08-01

    Low-dispersion slit spectrograms have been obtained of 34 faint objects that lie in the direction of the galactic bulge and have the Halpha line in emission upon a detectable continuum. Eleven of these are certain or probable symbiotic stars. A rough comparison with R CrB stars in the same area suggests that these brightest symbiotics in the bulge have in the mean M(v) approximately -3 to -4, which suggest Population II red giants rather than conventional Population I M-type objects. The sample also contains a number of hot stars having H and [O II] or [O III] in emission, as well as four conventional Be stars, and six certain or possible planetary nebulae. PMID:16578699

  19. Measuring Redshifts of Emission-line Galaxies Using Ramp Filters

    NASA Astrophysics Data System (ADS)

    Lesser, Ryan William; Bohman, John; McNeff, Mathew; Holden, Marcus; Moody, Joseph; Joner, Michael D.; Barnes, Jonathan

    2016-01-01

    Photometric redshifts are routinely obtained for galaxies without emission using broadband photometry. It is possible in theory to derive reasonably accurate (< 200 km/sec) photometric redshift values for emission-line objects using "ramp" filters with a linearly increasing/decreasing transmission through the bandpass. To test this idea we have obtained a set of filters tuned for isolating H-alpha at a redshift range of 0-10,000 km/sec. These filters consist of two that vary close to linearly in transmission, have opposite slope, and cover the wavelength range from 655nm - 685nm, plus a Stromgren y and 697nm filter to measure the continuum. Redshifts are derived from the ratio of the ramp filters indices after the continuum has been subtracted out. We are finishing the process of obtaining photometric data on a set of about 100 galaxies with known redshift to calibrate the technique and will report on our results.

  20. The nature of faint emission-line galaxies

    NASA Technical Reports Server (NTRS)

    Smetanka, John J.

    1993-01-01

    One of the results of faint galaxy redshift surveys is the increased fraction of galaxies which have strong emission-line spectra. These faint surveys find that roughly 50 percent of the galaxies have an equivalent width of (OII), W sub 3727, greater than 20 A while this fraction is less than 20 percent in the DARS survey. This has been interpreted as evidence for strong evolution in the galaxy population at redshifts less than 0.5. In order to further investigate the properties of the galaxies in faint redshift surveys, two important factors must be addressed. The first is the observed correlation between color, luminosity, and W sub 3727. There is a correlation between color and the strength of emission lines, bluer galaxies having stronger emission features, as evident for Markarian galaxies and for galaxies in Kennicutt's spectrophotometric atlas. This correlation also applies galaxies in faint redshift surveys. In addition, low luminosity galaxies have a larger average W sub 3727 (and bluer colors) than higher luminosity galaxies. This is illustrated for Kennicutt's low z late-type galaxies, for the Durham Faint Surveys, and for galaxies in SA68. The second factor which must be incorporated into any interpretation of the faint emission galaxies is the different luminosity functions for galaxies depending on color. This is usually modeled by varying M* for different color classes (or morphological types); however, the shape of the luminosity function is different for galaxies with different colors. Low luminosity, blue galaxies have a much larger number density than low luminosity, red galaxies. Furthermore, the low luminosity end of the blue galaxy luminosity function is not well fit by a Schechter function. These two factors have been included in a very simple, no-evolution, model for the galaxy population. This model uses the luminosity functions from Shanks (1990) and spectral energy distributions (SED's) from Bruzual (1988). W sub 3727 is predicted using

  1. First results from EBW emission diagnostics on COMPASS

    SciTech Connect

    Zajac, J.; Preinhaelter, J.; Aftanas, M.; Bilkova, P.; Boehm, P.; Fuchs, V.; Weinzettl, V.; Zacek, F.; Nanobashvili, S.

    2012-10-15

    COMPASS tokamak shots at low magnetic field feature overdense plasmas during the extended current flat-top phase. The first harmonic of the electron cyclotron emission is completely cutoff for O and X modes and so the emission caused by electron Bernstein waves (EBWs) propagating obliquely with respect to the magnetic field and undergoing so called EBW-X-O conversion process can be observed. We perform an angular scan of the EBW emission during a set of comparable shots in order to determine the optimum antenna direction. A weak dependence of the radiative temperature on the antenna angles indicates an influence of multiple reflections from the vessel wall. The low temperature at the mode conversion region is responsible for the collisional damping of EBW, which can explain several times lower measured radiative temperature than the electron temperature measured by the Thomson scattering system.

  2. A displaced-line velocity diagnostic and its application in a visualization engine

    NASA Astrophysics Data System (ADS)

    Bates, S. C.

    1989-04-01

    A technique for measuring three-dimensional velocity by imaging the displacement of a marked fluid line is described, together with its use in an automotive visualization engine. In a flow seeded with 2 3 μ phosphorescing particles, a line is excited by a UV laser beam, deformed by the local velocity field, and detected by stereo low-light-level video cameras. The derivation of velocity from digitized images is discussed and capabilities of the diagnostic are assessed. Some image data taken in the engine are shown and quantitative two-component velocity plots along the line are presented.

  3. Narrowband emission line imaging spectrometry using Savart plates

    NASA Astrophysics Data System (ADS)

    Maione, Bryan; Brickson, Leandra; Kudenov, Michael; Escuti, Michael

    2016-05-01

    Polarization spatial heterodyne interferometry (PSHI) allows for the development of compact, vibration insensitive, high spectral resolution sensors. Introducing the imaging qualities of a lenslet array extends the advantages of PSHI to imaging interferometers. The use of Savart plates enables a birefringent interferometer that obtains higher spectral resolution with fewer optical aberrations when compared to alternative designs. In this paper, we describe the design, construction, calibration and validation of a narrowband emission line imaging spectrometer (NELIS), based on Savart plates and liquid crystal polarization gratings, along with its associated theoretical model. This sensor is advantageous for spectral imaging in the areas of remote sensing, biomedical imaging and machine vision.

  4. The stability of QSO/AGN broad emission line clouds

    NASA Astrophysics Data System (ADS)

    Krinsky, I. S.; Puetter, R. C.

    1992-08-01

    Results of a numerical linear stability analysis of QSO/AGN emission-line clouds (ELCs) embedded within a confining hot intercloud medium (HIM) are reported. A first-order linear perturbation analysis reveals two important ionstabilities. The first instability is thermal in nature and arises in the interface region between the HIM and the ELC where thermal convection dominates gas heating; the growth time of the instability is approximately 1000 s, resulting in an ELC evaporation time of about 10 yr. The second instability is dynamic in nature, with the sound wave amplitude growing in response to radiative forces. The growth time of this instability is about 10 exp 6 s and essentially independent of the wavelength. The results suggest that if QSO/AGN ELCs have properties similar to those of the standard ELC model, then the broad-line region is in a constant state of flux in which ELCs continually form, are destroyed, and then re-formed.

  5. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines

    NASA Astrophysics Data System (ADS)

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission Hα (656 nm) and Hβ (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design.

  6. Design of a portable optical emission tomography system for microwave induced compact plasma for visible to near-infrared emission lines.

    PubMed

    Rathore, Kavita; Munshi, Prabhat; Bhattacharjee, Sudeep

    2016-03-01

    A new non-invasive diagnostic system is developed for Microwave Induced Plasma (MIP) to reconstruct tomographic images of a 2D emission profile. A compact MIP system has wide application in industry as well as research application such as thrusters for space propulsion, high current ion beams, and creation of negative ions for heating of fusion plasma. Emission profile depends on two crucial parameters, namely, the electron temperature and density (over the entire spatial extent) of the plasma system. Emission tomography provides basic understanding of plasmas and it is very useful to monitor internal structure of plasma phenomena without disturbing its actual processes. This paper presents development of a compact, modular, and versatile Optical Emission Tomography (OET) tool for a cylindrical, magnetically confined MIP system. It has eight slit-hole cameras and each consisting of a complementary metal-oxide-semiconductor linear image sensor for light detection. The optical noise is reduced by using aspheric lens and interference band-pass filters in each camera. The entire cylindrical plasma can be scanned with automated sliding ring mechanism arranged in fan-beam data collection geometry. The design of the camera includes a unique possibility to incorporate different filters to get the particular wavelength light from the plasma. This OET system includes selected band-pass filters for particular argon emission 750 nm, 772 nm, and 811 nm lines and hydrogen emission H(α) (656 nm) and H(β) (486 nm) lines. Convolution back projection algorithm is used to obtain the tomographic images of plasma emission line. The paper mainly focuses on (a) design of OET system in detail and (b) study of emission profile for 750 nm argon emission lines to validate the system design. PMID:27036771

  7. Laboratory Study of the Diagnostic Utility of the 3C/3D Line Ratio in Fe XVII

    NASA Astrophysics Data System (ADS)

    Brown, G. V.; Beiersdorfer, P.; Chen, H.; Chen, M. H.; Reed, K. J.

    2002-11-01

    Fe XVII x-ray emission is present in a multitude of sources observed by XMM- Newton and the Chandra X-Ray Observatory, such as, the corona of the Sun, Capella, HR1099, and Eta Pup. Two of the strongest lines observed in these spectra are the resonance and intercombination lines located at 15.01 and 15.26 Å, respectively. After being resolved in the Sun [1], calculations of the relative intensity, R, of these lines have varied by nearly a factor of two. As part of the laboratory astrophysics program at the electron beam ion traps ebit-i & ebit-ii located at the Lawrence Livermore National Laboratory we have measured this line ratio and found it to be significantly lower than most calculations [2]. However, our ratio is still higher than many of the ratios measured in the corona of the Sun. To address this discrepancy we have measured R as a function of the relative abundance of sodium-like Fe XVI [3]. Our results show that an Fe XVI innershell satellite line coincides with the intercombination line and can significantly reduce the apparent R. We measure R = 1.90 & ± 0.11 when the relative abundance of Fe XVI to Fe XVII is ~ 1. This explains the anomalously low ratios observed in the solar and stellar coronae previously believed to be the result of resonant scattering. The fact that the apparent relative intensity of the resonance and intercombination line in Fe XVII is sensitive to the strength of an Fe XVI innershell satellite, and therefore, the relative abundance of Fe XVI to Fe XVII, makes the line ratio a diagnostic of temperature. Work by the University of California, LLNL was performed under Contract No. W-7405-Eng-48 and supported by NASA SARA P.O. No. S-03958G and Smithsonian-CXO award No. EL9-1015A.

  8. New Strong-line Abundance Diagnostics for H II Regions: Effects of κ-distributed Electron Energies and New Atomic Data

    NASA Astrophysics Data System (ADS)

    Dopita, Michael A.; Sutherland, Ralph S.; Nicholls, David C.; Kewley, Lisa J.; Vogt, Frédéric P. A.

    2013-09-01

    Recently, Nicholls et al., inspired by in situ observations of solar system astrophysical plasmas, suggested that the electrons in H II regions are characterized by a κ-distribution of energies rather than a simple Maxwell-Boltzmann distribution. Here, we have collected together new atomic data within a modified photoionization code to explore the effects of both the new atomic data and the κ-distribution on the strong-line techniques used to determine chemical abundances in H II regions. By comparing the recombination temperatures (T rec) with the forbidden line temperatures (T FL), we conclude that κ ~ 20. While representing only a mild deviation from equilibrium, this result is sufficient to strongly influence abundances determined using methods that depend on measurements of the electron temperature from forbidden lines. We present a number of new emission line ratio diagnostics that cleanly separate the two parameters determining the optical spectrum of H II regions—the ionization parameter q or \\cal {U} and the chemical abundance, 12+log(O/H). An automated code to extract these parameters is presented. Using the homogeneous data set from van Zee et al., we find self-consistent results between all of these different diagnostics. The systematic errors between different line ratio diagnostics are much smaller than those found in the earlier strong-line work. Overall, the effect of the κ-distribution on the strong-line abundances derived solely on the basis of theoretical models is rather small.

  9. A recalibration of strong-line oxygen abundance diagnostics via the direct method and implications for the high-redshift universe

    NASA Astrophysics Data System (ADS)

    Brown, Jonathan S.; Martini, Paul; Andrews, Brett H.

    2016-05-01

    We use direct method oxygen abundances in combination with strong optical emission lines, stellar masses (M⋆), and star formation rates (SFRs) to recalibrate the N2, O3N2, and N2O2 oxygen abundance diagnostics. We stack spectra of ˜200 000 star-forming galaxies from the Sloan Digital Sky Survey in bins of M⋆ and SFR offset from the star-forming main sequence ( {Δ log (SSFR)}) to measure the weak emission lines needed to apply the direct method. All three new calibrations are reliable to within ±0.10 dex from log (M⋆/M⊙) ˜ 7.5-10.5 and up to at least 200 M⊙ yr-1 in SFR. The N2O2 diagnostic is the least subject to systematic biases. We apply the diagnostics to galaxies in the local Universe and investigate the M⋆-Z-SFR relation. The N2 and O3N2 diagnostics suggest the SFR dependence of the M⋆-Z-SFR relation varies with both M⋆ and {Δ log (SSFR)}, whereas the N2O2 diagnostic suggests a nearly constant dependence on SFR. We apply our calibrations to a sample of high-redshift galaxies from the literature, and find them to be metal-poor relative to local galaxies with similar M⋆ and SFR. The calibrations do reproduce direct method abundances of the local analogues. We conclude that the M⋆-Z-SFR relation evolves with redshift.

  10. NIR spectroscopy of Palomar emission-line galaxies

    NASA Astrophysics Data System (ADS)

    Mason, Rachel; Alonso-Herrero, Almudena; Bluck, Asa; Colina, Luis; Diaz, Ruben; Diaz-Santos, Tanio; Flohic, Helene; Gomez, Percy; Gonzalez-Martin, Omaira; Ho, Luis; Jorgensen, Inger; Lemoine-Busserolle, Marie; Levenson, Nancy; Lira, Paulina; McDermid, Richard; Perlman, Eric; Rodriguez-Ardila, Alberto; Riffel, Rogerio; Schiavon, Ricardo; Ramos Almeida, Cristina; Thanjavur, Karun; Winge, Claudia

    2012-02-01

    We propose GNIRS cross-dispersed spectroscopy of 60 Seyferts and LINERs from the Palomar galaxy sample. The spectra will advance our knowledge of AGN physics and lifecycles by demonstrating whether the accretion disk and nuclear dust properties change as a function of accretion rate, as predicted by theoretical models. They will be used to investigate the contribution of evolved stars to the line emission in LINERs, with implications for AGN demographics, and to make new stellar kinematic measurements for black hole mass estimates. The number and variety of spectral features that will appear in the data are expected to enable a wide range of science besides that highlighted in this proposal. For this reason, we plan a reduced proprietary period and to make the reduced spectra available to the community. We anticipate applying for time to observe the remaining emission-line galaxies in the (near-complete) Palomar sample over the next few semesters. The targets are distributed throughout the northern sky, making Gemini's queue mode ideal for this work. The fairly short observations are easily scheduled and can be carried out in suboptimal observing conditions.

  11. Far-Infrared Water Line Emissions from Circumstellar Outflows

    NASA Technical Reports Server (NTRS)

    Chen, Wesley; Neufeld, David A.

    1995-01-01

    We have modeled the far-infrared water line emission expected from circumstellar outflows from oxygen-rich late-type stars, as a function of the mass-loss rate and the terminal outflow velocity. For each mass-loss rate and terminal outflow velocity considered, we computed self-consistently the gas density, temperature, outflow velocity, and water abundance as a function of distance from the star. We then used an escape probability method to solve for the equilibrium level populations of 80 rotational states of water and thereby obtained predictions for the luminosity of a large number of far-infrared rotational transitions of water. In common with previous models, our model predicts that water will be copiously produced in the warm circumstellar gas and that water rotational emission will dominate the radiative cooling. However, our use of a realistic radiative cooling function for water leads to a lower gas temperature than that predicted in previous models. Our predictions for the far-infrared water line luminosities are consequently significantly smaller than those obtained in previous studies. Observations to be carried out by the Infrared Space Observatory will provide a crucial test of the models presented here.

  12. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Sung, C.; White, A. E.; Irby, J. H.; Leccacorvi, R.; Vieira, R.; Oi, C. Y.; Peebles, W. A.; Nguyen, X.

    2012-10-01

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have kθ ≤ 4.8 cm-1 (kθρs < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper.

  13. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Mod

    SciTech Connect

    Sung, C.; White, A. E.; Irby, J. H.; Leccacorvi, R.; Vieira, R.; Oi, C. Y.; Peebles, W. A.; Nguyen, X.

    2012-10-15

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have k{sub {theta}}{<=} 4.8 cm{sup -1} (k{sub {theta}}{rho}{sub s} < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper.

  14. Design of a correlation electron cyclotron emission diagnostic for Alcator C-Mod.

    PubMed

    Sung, C; White, A E; Irby, J H; Leccacorvi, R; Vieira, R; Oi, C Y; Peebles, W A; Nguyen, X

    2012-10-01

    A correlation electron cyclotron emission (CECE) diagnostic has been installed in Alcator C-Mod. In order to measure electron temperature fluctuations, this diagnostic uses a spectral decorrelation technique. Constraints obtained with nonlinear gyrokinetic simulations guided the design of the optical system and receiver. The CECE diagnostic is designed to measure temperature fluctuations which have k(θ) ≤ 4.8 cm(-1) (k(θ)ρ(s) < 0.5) using a well-focused beam pattern. Because the CECE diagnostic is a dedicated turbulence diagnostic, the optical system is also flexible, which allows for various collimating lenses and antenna to be used. The system overview and the demonstration of its operability as designed are presented in this paper. PMID:23126971

  15. Star formation rates and chemical abundances of emission-line galaxies in intermediate-redshift clusters

    NASA Astrophysics Data System (ADS)

    Mouhcine, M.; Bamford, S. P.; Aragón-Salamanca, A.; Nakamura, O.; Milvang-Jensen, B.

    2006-06-01

    We examine the evolutionary status of luminous, star-forming galaxies in intermediate-redshift clusters by considering their star formation rates (SFRs) and the chemical and ionization properties of their interstellar emitting gas. Our sample consists of 17 massive, star-forming, mostly disc galaxies with MB<~-20, in clusters with redshifts in the range 0.31 <~z<~ 0.59, with a median of = 0.42. We compare these galaxies with the identically selected and analysed intermediate-redshift field sample of Mouhcine et al., and with local galaxies from the Nearby Field Galaxy Survey of Jansen et al. From our optical spectra, we measure the equivalent widths of [OII]λ3727, Hβ and [OIII]λ5007 emission lines to determine diagnostic line ratios, oxygen abundances and extinction-corrected SFRs. The star-forming galaxies in intermediate-redshift clusters display emission-line equivalent widths which are, on average, significantly smaller than measured for field galaxies at comparable redshifts. However, a contrasting fraction of our cluster galaxies have equivalent widths similar to the highest observed in the field. This tentatively suggests a bimodality in the SFRs per unit luminosity for galaxies in distant clusters. We find no evidence for further bimodalities, or differences between our cluster and field samples, when examining additional diagnostics and the oxygen abundances of our galaxies. This maybe because no such differences exist, perhaps because the cluster galaxies which still display signs of star formation have recently arrived from the field. In order to examine this topic with more certainty, and to further investigate the way in which any disparity varies as a function of cluster properties, larger spectroscopic samples are needed.

  16. Comprehensive, nonintercepting electron-beam diagnostics using spontaneous emission

    SciTech Connect

    Lumpkin, A.H.

    1989-01-01

    Characterization and optimization of electron-beam parameters are important aspects of optimizing free-electron laser (FEL) performance. The visible spontaneous emission ({lambda}{approximately}650 nm) from the 5-meter long undulator of the Boeing FEL experiment can be characterized in sufficient detail with a streak/spectrometer to deduce time-resolved electron-beam spatial position and profile, micropulse duration, and energy. 7 refs., 13 figs., 2 tabs.

  17. Asymmetries in coronal spectral lines and emission measure distribution

    SciTech Connect

    Tripathi, Durgesh; Klimchuk, James A.

    2013-12-10

    It has previously been argued that (1) spicules do not provide enough pre-heated plasma to fill the corona, and (2) even if they did, additional heating would be required to keep the plasma hot as it expands upward. Here we address whether spicules play an important role by injecting plasma at cooler temperatures (<2 MK), which then gets heated to coronal values at higher altitudes. We measure red-blue asymmetries in line profiles formed over a wide range of temperatures in the bright moss areas of two active regions. We derive emission measure distributions from the excess wing emission. We find that the asymmetries and emission measures are small and conclude that spicules do not inject an important (dominant) mass flux into the cores of active regions at temperatures >0.6 MK (log T > 5.8). These conclusions apply not only to spicules but also to any process that suddenly heats and accelerates chromospheric plasma (e.g., a chromospheric nanoflare). The traditional picture of coronal heating and chromospheric evaporation appears to remain the most likely explanation of the active region corona.

  18. Investigation of Nuclear Gamma Ray Line Emission Associated with Lightning

    NASA Astrophysics Data System (ADS)

    Boggs, S. E.; Millan, R. M.; Eack, K.; Aulich, G. D.

    2005-12-01

    The first conclusive observations of X-rays associated with thunderstorm activity were made in the 1980's and the prompt emission has been interpreted as bremsstrahlung produced by lightning-accelerated electrons. In 2004, Greenfield et al. reported the first detection of delayed gamma ray emission, with flux peaking 70 minutes after a lightning stroke and decaying exponentially over 50 minutes. They suggested the delayed gamma rays are a result of nuclear reactions in the atmosphere, creating excited Chlorine-39 and decaying with a 56-minute half-life. These results are compelling, but inconclusive; instrumentation capable of measuring the energy spectrum with high precision is necessary to confirm the existence of nuclear line emission associated with lightning. During June-September 2005, we used a spare RHESSI 7 cm-diameter segmented coaxial germanium spectrometer to continuously monitor gamma radiation on South Baldy Peak (10,800 ft) in New Mexico. The detector monitors gamma rays between ~18 keV-10 MeV with an energy resolution of ~2 keV@835 keV. South Baldy is the site of Langmuir Lab and was chosen to take advantage of other lightning research instrumentation located there, including New Mexico Tech's 3D Lightning Mapping Array (LMA) which can determine the location of a lightning stroke to within about 50m. We describe the experiment and present the initial results.

  19. Outflow and hot dust emission in broad absorption line quasars

    SciTech Connect

    Zhang, Shaohua; Zhou, Hongyan; Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Jiang, Peng; Zhang, Kai E-mail: whywang@mail.ustc.edu.cn

    2014-05-01

    We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (β{sub NIR}) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here β{sub NIR} is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with β{sub NIR} in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with β{sub NIR} than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as β{sub NIR} increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

  20. Quasi-separatrix layers and three-dimensional reconnection diagnostics for line-tied tearing modes

    NASA Astrophysics Data System (ADS)

    Richardson, Andrew S.; Finn, John M.

    2011-10-01

    In three-dimensional magnetic configurations for a plasma in which no closed field line or magnetic null exists, no magnetic reconnection can occur, by the strictest definition of reconnection. A finitely long pinch with line-tied boundary conditions, in which all the magnetic field lines start at one end of the system and proceed to the opposite end, is an example of such a system. Nevertheless, for a long system of this type, the physical behavior in resistive magnetohydrodynamics (MHD) essentially involves reconnection. This has been explained in terms comparing the geometric and tearing widths. The concept of a quasi-separatrix layer was developed for such systems. We study a model for a line-tied system in which the corresponding periodic system has an unstable tearing mode. We analyze this system in terms of two magnetic field line diagnostics, the squashing factor and the electrostatic potential difference, which has been used in kinematic reconnection studies. We discuss the physical and geometric significance of these two diagnostics and compare them in the context of discerning tearing-like behavior in line-tied modes.

  1. Quasi-separatrix layers and three-dimensional reconnection diagnostics for line-tied tearing modes

    NASA Astrophysics Data System (ADS)

    Richardson, A. S.; Finn, J. M.

    2012-05-01

    In three-dimensional magnetic configurations for a plasma in which no closed field line or magnetic null exists, no magnetic reconnection can occur, by the strictest definition of reconnection. A finitely long pinch with line-tied boundary conditions, in which all the magnetic field lines start at one end of the system and proceed to the opposite end, is an example of such a system. Nevertheless, for a long system of this type, the physical behavior in resistive magnetohydrodynamics (MHD) essentially involves reconnection. This has been explained in terms comparing the geometric and tearing widths [1,2]. The concept of a quasi-separatrix layer [3,4] was developed for such systems. In this paper we study a model for a line-tied system in which the corresponding periodic system has an unstable tearing mode. We analyze this system in terms of two magnetic field line diagnostics, the squashing factor[5-7] and the electrostatic potential difference [8,9] which has been used in kinematic reconnection studies. We discuss the physical and geometric significance of these two diagnostics and compare them in the context of discerning tearing-like (reconnection-like) behavior in line-tied modes.

  2. Self-calibrating magnetic field diagnostics in beam emission spectroscopy

    SciTech Connect

    Voslamber, D.

    1995-04-01

    Magnetic field diagnostics in tokamaks using the motional Stark effect in fast neutral beams have been based on two kinds of polarimetry which we call ``static`` and ``dynamic.`` A detailed analysis shows that static polarimetry presents a number of advantages over dynamic polarimetry, provided it is made complete in the sense that a sufficient number of polarization analyzers are installed and different parts of the spectrum are explored to yield full information on the set of unknowns inherent in the problem. A detailed scheme of complete static polarimetry is proposed, including the case where an in-vessel mirror with changing characteristics (coating by impurities) is placed in front of the optical detection system. The main merit of this scheme relies on the fact that it is self-calibrating with respect to both the characteristics of the mirror and the transmission of the different polarization channels, the latter item implying that it is uniquely based on relative measurements of spectra. Further advantages are a greater flexibility with regard to different kinds of diagnostics and the circumstance that the technical equipment is less involved. The above scheme is based on a detection system of moderate etendue exploiting a large spectral domain, which is the regime where static polarimetry usually operates. It is also possible, however, to work with large etendue and a small spectral domain, such as commonly adopted in dynamic polarimetry. Using such a regime, static polarimetry loses the advantages mentioned above but gains, as a new advantage, the benefit of a comparatively lower level of photon noise. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  3. Infrared coronal emission lines and the possibility of their laser emission in Seyfert nuclei

    NASA Technical Reports Server (NTRS)

    Greenhouse, Matthew A.; Feldman, Uri; Smith, Howard A.; Klapisch, Marcel; Bhatia, Anand K.; Bar-Shalom, Avi

    1993-01-01

    Results are presented from detailed balance calculations, and a compilation of atomic data and other model calculations designed to support upcoming ISO and current observing programs involving IR coronal emission lines, together with a table with a complete line list of infrared transitions within the ground configurations 2s2 2p(k), 3s2 3p(k), and the first excited configurations 2s 2p and 3s 3p of highly ionized astrophysically abundant elements. The temperature and density parameter space for dominant cooling via IR coronal lines is presented, and the relationship of IR and optical coronal lines is discussed. It is found that, under physical conditions found in Seyfert nuclei, 14 of 70 transitions examined have significant population inversions in levels that give rise to IR coronal lines. Several IR coronal line transitions were found to have laser gain lengths that correspond to column densities of 10 exp 24-25/sq cm which are modeled to exist in Seyfert nuclei. Observations that can reveal inverted level populations and laser gain in IR coronal lines are suggested.

  4. Flux-Calibrated Emission-Line Imaging of Extended Sources Using GTC/OSIRIS Tunable Filters

    NASA Astrophysics Data System (ADS)

    Mayya, Y. D.; Rosa González, D.; Vega, O.; Méndez-Abreu, J.; Terlevich, R.; Terlevich, E.; Bertone, E.; Rodríguez-Merino, L. H.; Muñoz-Tuñón, C.; Rodríguez-Espinosa, J. M.; Sánchez Almeida, J.; Aguerri, J. A. L.

    2012-08-01

    We investigate the utility of the tunable filters (TFs) for obtaining flux-calibrated emission-line maps of extended objects such as galactic nebulae and nearby galaxies using the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) at the 10.4-m Gran Telescopio Canarias (GTC). Despite the relatively large field of view (FoV) of OSIRIS (8' × 8'), the change in wavelength across the field (~80 Å) and the long tail of the TF spectral response function are hindrances for obtaining accurate flux-calibrated emission-line maps of extended sources. The purpose of this article is to demonstrate that emission-line maps useful for diagnostics of nebulae can be generated over the entire FoV of OSIRIS if we make use of theoretically well-understood characteristics of TFs. We have successfully generated the flux-calibrated images of the nearby large late-type spiral galaxy M101 in the emission lines of Hα, [N II]λ6583, [S II]λ6716 and [S II]λ6731. We find that the present uncertainty in setting the central wavelength of TFs (~1 Å) is the biggest source of error in the emission-line fluxes. By comparing the Hα fluxes of H II regions in our images with the fluxes derived from Hα images obtained using narrow-band filters, we estimate an error of ~11% in our fluxes. The flux-calibration of the images was carried out by fitting the Sloan Digital Sky Survey (SDSS) griz magnitudes of in-frame stars with the stellar spectra from the SDSS spectral database. This method resulted in an accuracy of 3% in flux-calibration of any narrow-band image, which is as good as, if not better than, what has been feasible using the observations of spectrophotometric standard stars. Thus time-consuming calibration images need not be taken. A user-friendly script under the IRAF environment was developed and is available on request. Based on observations made with the Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio del Roque de los Muchachos of the

  5. Iron and helium emission lines in classical T Tauri stars

    NASA Astrophysics Data System (ADS)

    Beristain, Georgina

    Results are presented for the He emission in 31 CTTS from the Taurus-Auriga molecular cloud spanning two orders of magnitude in the mass accretion rate, and for the Fe emission in DR Tau, based on a series of high resolution echelle spectra. The He lines admit a description in terms of a narrow component ( NC) and a broad component (BC). The NC has FWHM between 32-55 km/s and centroid velocities near zero km/s or moderately redshifted, consistent with an origin in the postshock region of the magnetospheric accretion model. The BC, with FWHM between 128 and 287 km/s and centroid velocities between -93 and +35 km/s, includes a wind and an accretion component; we argue the BC is predominantly formed in the wind. Estimates of the wind and accretion component equivalent widths are oppositely related to the NC, so the NC equivalent width increases with the accretion component but decreases as the wind component increases. The NC is undetectable where profiles appear dominated by the wind, requiring a source of veiling other than the accretion shock to account for the observed continuum excess. Intensity ratios indicate that physical conditions are nearly uniform in the NC but span a range in the BC. For DR Tau, the range of morphologies in 62 unblended Fe I and Fe II lines can be resolved in terms of a narrow component (NC) that dominates the weakest lines, and a broad component (BC) that dominates the strongest lines. The (NC) has FWHM ~20 km/s and centroid velocity near zero km/s. The (BC) has FWHM ~100 km/s, and a tendency to be blueshifted by <=10 km/s. Estimates of iron line opacities τ and column densities N yield τNC ~ 3 × τBC, NFeI >~ 1017 - 1018 cm-2 , and NFeII >~ 1018 - 1019 cm-2 for the BC. Estimates of kinetic temperature for iron suggest that the NC gas is hotter than the BC by several thousand degrees. For iron, the NC is consistent with an origin in the postshock gas while the BC may originate in the inner accretion disk close to the corotation radius.

  6. 40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use...

  7. 40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use...

  8. 40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use...

  9. 40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use...

  10. 40 CFR 1060.515 - How do I test EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and EPA Cold-Weather Fuel Lines for permeation emissions? 1060.515 Section 1060.515 Protection of... Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines for permeation emissions? Measure emission as follows for EPA Nonroad Fuel Lines and EPA Cold-Weather Fuel Lines: (a) Prior to permeation testing, use...