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Sample records for 6307a emission line

  1. 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.

  2. 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.

  3. 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.

  4. Modeling line emission in PDRs

    NASA Astrophysics Data System (ADS)

    Le Bourlot, J.

    2000-11-01

    The formation of emission lines in a diluted medium results from a large number of conspiring physical processes. When trying to compute a line intensity or (harder) a line profile from first principles, one has to take into account at least three different kind of processes: Atomic or molecular physics data. An accurate knowledge of radiative and collisional transition probabilities is required to determine the population of excited levels which rules the formation of emission lines. Thermodynamical equilibrium is almost never established, so that detailed balance equations need to be solved. Unfortunately many important data are still badly known. Structure and dynamics of the emitting medium. Local emissivities at a specific point depend at least on the local temperature and density of the gas, but often also on other less accessible parameters such as the turbulence state of the gas, a magnetic field or the existence of rapidly evolving transients such as shocks. Self consistent models which would include all relevant processes are out of reach numerically, and choices must be made among the more relevant physical processes to include. Radiative transfer effects. For a few relevant interstellar lines, the opacity is small enough that the emergent emissivity is just the sum of all local emissivities along the line of sight. Unfortunately, most lines are not so easy to cope with and a minimal radiative transfer formalism must be included. Various degrees of sophistication are possible, from a simple escape probability theory to full wavelength dependent line transfer. On the whole, line modelling is still more an art than a science. One should be well aware of the various assumptions made in a model before applying it to some particular observational result.

  5. Evolution of emission line galaxies

    NASA Astrophysics Data System (ADS)

    Horowitz, Irwin Kenneth

    1994-01-01

    This thesis compares two samples of emission line galaxies, selected on the basis of the strength of their (OIII)lambda lambda 4959, 5007 and/or H beta lambda 4861 emission lines. The distant sample is drawn from the 4 Shooter transit survey undertaken by Schmidt, Schneider and Gunn (1994 and references therein) and consists of 370 galaxies with emission line equivalent widths in excess of 50A and fluxes above well-defined wavelength-dependent limits. This survey consists of 6 narrow strips of the sky covering approximately 62 square degrees. Each of these galaxies is classified by using line ratio diagnostics from the moderate resolution spectra taken to identify the emission line. The nearby sample is taken from the first CfA Northern Sky Redshift Survey, and consists of 81 galaxies from Burg (1987) with (OIII)lambda lambda 4959, 5007 EW is greater than or equal to 23.75A and an additional 26 Seyfert galaxies from Edelson (1987). This sample is observed on the 1.5m Oscar Meyer telescope using the Echelle Spectrograph in a low-resolution, long slit mode (McCarthy, 1988). Each of the 107 galaxies is observed twice, along per pendicular axes over a wavelength range from 4350A to 7200A, which covers the emission lines of interest such as H beta lambda 4861, (Olll)lambda lambda 4959, 5007 and H alpha lambda 6563. These data are used both to classify the 107 galaxies from their line ratio diagnostics as well as to model the spatial and spectral light distribution on the plane of the sky for a comparison of how each would appear in the distant survey as a function of redshift. Maximum redshifts in both the nearby and the distant survey are determined for each CfA galaxy, and predicted number counts, based on both a no-evolution model as well as a model incorporating density evolution, are made from the corresponding ratio of accessible volumes in the two surveys. Corrections are made to the predicted counts to account for sample incompletenesses and the overdensity of

  6. Evolution of Emission Line Galaxies

    NASA Astrophysics Data System (ADS)

    Horowitz, Irwin K.

    1995-02-01

    This thesis compares two samples of emission line galaxies, selected on the basis of the strength of their O III and/or H-beta emission lines. The distant sample has been drawn from the 4-Shooter transit survey undertaken by Schmidt, Schneider and Gunn (1994, AJ, 107, 1245 and references therein), and consists of 370 galaxies with emission line equivalent widths in excess of 50A and fluxes above well-defined wavelength-dependent limits. This survey the moderate resolution spectra taken to identify the emission line. The nearby sample has been taken from the first CfA Northern Sky Redshift Survey, and consists of 81 galaxies from Burg (1987, Ph.D. thesis, MIT, Cambridge, MA) with O III EW >= 23.75A and an additional 26 Seyfert galaxies fbeen observed on the 1.5m Oscar Meyer telescope using the Echelle Spectrograph in a low-resolution, long slit mode (McCarthy, 1988, Ph.D. thesis, Caltech, Pascovers the emission lines of interest such as H-beta, O II. These data have been used both to classify the 107 galaxies from their line ratio diagnostics as well as to model the spatial and spectral light distributions on the plane of the sky for a comparison of how each would appear in the distant survey as a function of redshift. Maximum redshifts in both the nearby and the distant survey have been determined for each CfA galaxy, and predicted number counts, based on both a no-evolution model as well as a model incorporating density evolution, have been made from the corresponding ratio of accessible volumes in the two surveys. Corrections were made to the predicted counts to account for sample incompletenesses and the overdensity of the CfA survey relative to the average density of galaxies in the "local" universe. These predicted counts were comclass. The results from this cono-evolution model for emission line galaxies out to z~0.5, and do not support the conjecture (Broadhurst et al., 1988, MNRAS, 235, 827; Colless et al., 1990, MNRAS, 244, 408) that there is an evolving

  7. 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.

  8. The chandra emission line project

    NASA Astrophysics Data System (ADS)

    Brickhouse, Nancy S.; Drake, Jeremy J.

    2000-11-01

    With the launches of the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission-Newton satellite, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources (Capella, Procyon, and HR 1099) are providing not only invaluable grating calibration data, but also benchmarks for plasma spectral models. These models are needed to interpret data not only from stellar coronae, but also from galaxies, clusters of galaxies, supernova remnants and other astrophysical sources. They have been called into question in recent years as problems with understanding low to moderate resolution X-ray and EUV data have arisen. The Emission Line Project is a collaborative effort sponsored by the Chandra X-ray Center to improve the models, with the first phase concentrating on the comparison of models to the calibration data. Goals of these comparisons are to (1) to determine and verify accurate and robust diagnoistcs and (2) to identify and prioritize issues in fundamental spectroscopy requiring further investigation. We will discuss the progress on this project to date. .

  9. PyNeb: Analysis of emission lines

    NASA Astrophysics Data System (ADS)

    Luridiana, V.; Morisset, C.; Shaw, R. A.

    2013-04-01

    PyNeb (previously PyNebular) is an update and expansion of the IRAF package NEBULAR; rewritten in Python, it is designed to be more user-friendly and powerful, increasing the speed, easiness of use, and graphic visualization of emission lines analysis. In PyNeb, the atom is represented as an n-level atom. For given density and temperature, PyNeb solves the equilibrium equations and determines the level populations. PyNeb can compute physical conditions from suitable diagnostic line ratios and level populations, critical densities and line emissivities, and can compute and display emissivity grids as a function of Te and Ne. It can also deredden line intensities, read and manage observational data, and plot and compare atomic data from different publications, and compute ionic abundances from line intensities and physical conditions and elemental abundances from ionic abundances and icfs.

  10. On the interpretation of chromospheric emission lines

    NASA Technical Reports Server (NTRS)

    Judge, P. G.

    1990-01-01

    This paper reexamines the formation of ultraviolet emission lines in stellar chromospheres, using detailed radiative transfer calculations and relatively simple methods based on approximate line cooling rates, including escape probabilities. Approximations for the cooling integrals are demonstrated to work well for 'effectively thin' chromospheric lines. Two cases are identified, whose behavior can be understood using Ayres's (1979) chromospheric scaling laws relating the chromospheric structure to stellar properties: those of inactive stars, like cool giants, and more active stars like the sun.

  11. Twenty southern peculiar emission-line stars

    NASA Technical Reports Server (NTRS)

    Carlson, E. D.; Henize, K. G.

    1979-01-01

    Observational data for 20 southern stars having emission-line spectra that suggest a significant degree of mass ejection are given in order to present an atlas of their spectra and to give a quantitative description of their appearance during the 1961-62 epoch. Most of the stars are P Cygni stars; others include nova-like, peculiar Be, and symbiotic stars, as well as stellar planetary nebulae and emission-line binaries, all of whose spectra were obtained with the Newtonian two-prism Zeiss Spectrograph and the 74-inch reflector at Mount Stromlo Observatory. It is noted that among the P Cygni stars, there is a strong correlation between the a-e expansion velocity and the strength of Balmer emission, while in both the P Cygni and the Bep stars, there is positive dependence of Fe II and negative dependence of (Fe II) emission strengths on Balmer emission strength.

  12. 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.

  13. 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.

  14. Chandra and the Emission Line Project

    NASA Technical Reports Server (NTRS)

    Brickhouse, N. S.; Drake, J. J.

    2000-01-01

    Calibration data obtained for the Chandra High Energy Transmission Grating and the Low Energy Transmission Grating Spectrometers are allowing us to test plasma spectral models against bright coronal sources with a range of electron temperatures. The three Emission Line Project targets - Capella, Procyon, and HR 1099 - are bright, well-studied X-ray and EUV emitters. The goals of the Emission Line Project are to determine and verify accurate and robust diagnostics; to identify and prioritize problems in fundamental spectroscopy; and to accelerate the improvement of the atomic database needed for modeling.

  15. Chandra and the Emission Line Project

    NASA Astrophysics Data System (ADS)

    Brickhouse, N. S.; Drake, J. J.

    2000-10-01

    Calibration data obtained for the Chandra High Energy Transmission Grating and the Low Energy Transmission Grating Spectrometers are allowing us to test plasma spectral models against bright coronal sources with a range of electron temperatures. The three Emission Line Project targets - Capella, Procyon, and HR 1099 - are bright, well-studied X-ray and EUV emitters. The goals of the Emission Line Project are to determine and verify accurate and robust diagnostics; to identify and prioritize problems in fundamental spectroscopy; and to accelerate the improvement of the atomic database needed for modeling.

  16. Polarization of Forbidden Coronal Emission Lines

    NASA Astrophysics Data System (ADS)

    Li, Hao

    2017-08-01

    Since the magnetic field is responsible for most manifestations of solar ac- tivity in the corona, one of the most challenging problems in solar physics is the diagnostics of solar magnetic fields. We present our investigation on polarization of forbidden coronal emission lines ( Fe XIV 5303 A, Fe X 6374 A Fe XI 7892 A, Fe XIII 10747 A, Si X 14300 A, Mg VIII 30280 A and Si IX 39290 A), which shows that Si IX 39290 A line may be a suitable line for future observation.

  17. Modeling BL Lac Emission Lines: A Preview

    NASA Astrophysics Data System (ADS)

    Fernandes, Sunil; Schlegel, Eric M.; Packham, Chris

    2012-12-01

    We present preliminary results based on a model of the emission from active galactic nuclei (AGN) combining special relativistic magnetohydrodynamics (RMHD), radiative transfer effects, and the spin rate of the super-massive black hole (SMBH). The RMHD code, PLUTO, can compute radiative cooling losses at each user definable time step and we use these capabilities to generate spectra. Additionally, the code will be used to model temporal variability of total broad band flux and line emission. We will use these model results to compare with observed spectra of AGN, focusing on blazars with the goal of predicting line strengths in BL Lac objects. We present methods for estimating line strengths from our simulated results.

  18. 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.

  19. X-ray line emission from Capella

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; Boldt, E. A.; Serlemitsos, P. J.; White, N. E.; Becker, R. H.; Mushotzky, R. F.; Smith, B. W.

    1979-01-01

    X-ray emission-line components from Mg, Si, S, and Fe are unambiguously detected from Capella with the solid-state spectrometer onboard the Einstein Observatory. The X-ray spectrum is inconsistent with an isothermal corona, and requires components between 6-million K and at least 24-million K for an adequate fit. An inhomogeneous corona in which the X-ray emitting plasma is confined to magnetically contained loops appears to be reconcilable with all of the experimental evidence.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Molecular clouds photoevaporation and FIR line emission

    NASA Astrophysics Data System (ADS)

    Vallini, L.; Ferrara, A.; Pallottini, A.; Gallerani, S.

    2017-01-01

    With the aim of improving predictions on far infrared (FIR) line emission from Giant Molecular Clouds (GMC), we study the effects of photoevaporation (PE) produced by external far-ultraviolet (FUV) and ionizing (extreme-ultraviolet, EUV) radiation on GMC structure. We consider three different GMCs with mass in the range M_GMC = 10^{3-6} {M_{⊙}}. Our model includes: (i) an observationally-based inhomogeneous GMC density field, and (ii) its time evolution during the PE process. In the fiducial case (MGMC ≈ 105M⊙), the photoevaporation time (tpe) increases from 1 Myr to 30 Myr for gas metallicity Z=0.05-1 Z_{⊙}, respectively. Next, we compute the time-dependent luminosity of key FIR lines tracing the neutral and ionized gas layers of the GMCs, ([C II] at 158 {μ m}, [O III] at 88 μ m) as a function of G0, and Z until complete photoevaporation at tpe. We find that the specific [C II] luminosity is almost independent on the GMC model within the survival time of the cloud. Stronger FUV fluxes produce higher [C II] and [O III] luminosities, however lasting for progressively shorter times. At Z = Z⊙ the [C II] emission is maximized (L_CII≈ 10^4 {L_{⊙}} for the fiducial model) for t<1 {Myr} and log G0 ≥ 3. Noticeably, and consistently with the recent detection by Inoue et al. (2016) of a galaxy at redshift z ≈ 7.2, for Z≤ 0.2 {Z_{⊙}} the [O III] line might outshine [C II] emission by up to ≈1000 times. We conclude that the [O III] line is a key diagnostic of low metallicity ISM, especially in galaxies with very young stellar populations.

  5. The Local [CII] Emission Line Luminosity Function

    NASA Astrophysics Data System (ADS)

    Hemmati, Shoubaneh

    2017-01-01

    I present, for the first time, the local [CII]158 $\\mu$m emission line luminosity function measured using a sample of more than 500 galaxies from the RBGS. [CII] luminosities are measured from the Herschel PACS observations of the LIRGs in the GOALS survey and estimated for the rest of the sample based on the far-IR luminosity and color. The sample covers 91.3% of the sky and is complete at $S_{60\\mu m} > 5.24 Jy$. We calculated the completeness as a function of [CII] line luminosity and distance, based on the far-IR color and flux densities. The [CII] luminosity function is constrained in the range $\\sim 10^{7-9} \\ L_{\\odot}$ from both the 1/Vmax and the STY maximum likelihood methods. The shape of our derived [CII] emission line luminosity function agrees well with the IR luminosity function. For the CO(1-0) and [CII] luminosity functions to agree, we propose a varying ratio of [CII]/CO(1-0) as a function of CO luminosity, with larger ratios for fainter CO luminosities. Limited [CII] high redshift observations as well as estimates based on the IR and UV luminosity functions, are suggestive of an evolution in the [CII] luminosity function similar to the evolution trend of the cosmic star formation rate density. ALMA with full capability will be able to confirm this prediction.

  6. X-ray line emission from Capella

    NASA Technical Reports Server (NTRS)

    Holt, S. S.; White, N. E.; Becker, R. H.; Boldt, E. A.; Mushotzky, R. F.; Serlemitsos, P. J.; Smith, B. W.

    1979-01-01

    X-ray emission line components from Mg, Si, S and Fe were unambiguously detected from Capella with the Solid-State Spectrometer onboard the Einstein Observatory. The X-ray spectrum is inconsistent with an isothermal corona, and requires components between 6,000,000 K and at least 24,000,000 K for an adequate fit. An inhomogeneous corona in which the X-ray emitting plasma is confined to magnetically-contained loops appears to be reconcilable with all of the experimental evidence.

  7. 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.

  8. 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.

  9. Continuum and line emission in Cygnus A

    NASA Astrophysics Data System (ADS)

    Stockton, Alan; Ridgway, Susan E.; Lilly, Simon J.

    1994-08-01

    We present the results from (1) imaging observations of Cygnus A in five essentially line-free continuum bands with central wavelengths ranging from 0.34 to 2.1 microns. (2) imaging observations in five narrowband filters centered on the emission lines H beta(O III) lambda5007, H alpha(N II) lambda6583, and (S II) lambda lambda6716, 6731, and (3) deep spectroscopy covering the entire central region of Cyg A. We confirm that the featureless spectrum component is to be identified with the prominent double morphology at the center of Cyg A, but uncertainties in the distribution of the dust in this region tend to limit the accuracy with which we can determine its morphology and spectral-energy distribution (SED). From regions that appear to be least affected by obscuration, we find fv is approximately v-0.1 for this component. This SED could be consistent with free-free emission, a population of young stars, or a quasar continuum scattered by electrons, but probably not with a quasar continuum scattered by dust, which would be bluer. Our spectroscopy places an upper limit on the equivalent width of broad H beta that is well below that of typical quasars, showing that this flat-spectrum component (FSC) is almost certainly not dominated by scattered quasar radiation. Appeals to scattering by hot electrons to smear the scattered broad lines into invisibility appear to fail because the large density scale height of the electrons and the inefficiency of electron scattering should result in smoother and more extensive structure than we observe. Although the relative SED is consistent with free-free emission, the required amount of hot gas violates other observational constraints. At high angular resolution, the apparent morphology of the FSC is spiral-like. Although this impression may be partly due to obscuration, the distribution of the dust itself only serves to reinforce the spiral-like nature of the material with which it is associated. We conclude that the FSC is most

  10. 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.

  11. 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.

  12. 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.

  13. Modeling of UV Emission Lines in AM HER Systems

    NASA Astrophysics Data System (ADS)

    Cash, Jennifer; Howell, Steve

    We present preliminary models of the UV emission lines from the accretion streams in AM Her systems. These models are based on the theory that the emission lines are due to reprocessing of the high energy photons from the hot spot and shock regions by the accretion stream. The models were developed using the radiative-collisional equilibrium program CLOUDY. They show the same trends of emission line strength versus magnetic field strength as seen in IUE observations. We have also examined the effects of other parameters on the predicted emission line strengths. The development of more sophisticated models is underway.

  14. CO line emission from circumstellar envelopes

    NASA Astrophysics Data System (ADS)

    Teyssier, D.; Hernandez, R.; Bujarrabal, V.; Yoshida, H.; Phillips, T. G.

    2006-04-01

    Aims.We present the results of a multi-transition CO observational program conducted on a sample of AGB and post-AGB stars envelopes. We have collected maps and single pointing observations of these envelopes in 5 rotational transitions ranging from J = 1-0 to J = 6-5, including in particular new observations of the CO line at 691 GHz at the CSO. The use of such a set of mm and submm CO line on stellar envelopes is rare and limited to the work of some authors on IRC+10216. Methods: .Using a model for the CO emission of an AGB circumstellar envelope, in combination with a standard LVG approach, we have conducted a systematic modelling analysis using the whole set of CO data collected for a sample of 12 sources. We simultaneously fit all five transitions, taking into account the spatial information provided by the maps. Results: .We find mass-loss rates in the range 1 × 10-7 to 4 × 10-4 M_⊙/yr, and envelope temperatures ranging from 20 K to 1000 K at a radius of 1016 cm. There seem to be a general anti-correlation between mass loss rates and temperature, the high mass loss rate AGBs having low temperatures, and vice versa. We show that most AGB data can be fitted using a constant mass loss rate, at least within the calibration uncertainties associated with the data collected at different frequencies. For some cases though (e.g. CIT 6, R Hya, χ Cyg), a change in the mass loss rate history needs to be invoked to reconcile data at low- and high-J, a scenario already mentioned by several authors to explain observations of WX Psc.

  15. Extended optical-emission-line gas in powerful radio galaxies

    SciTech Connect

    Baum, S.A.

    1987-01-01

    Results of a search for extended optical-emission-line gas in 43 powerful radio galaxies are presented. Spatially extended optical-emission-line gas is common in these galaxies. The extent and luminosity of the emission-line gas in powerful radio galaxies is an order of magnitude greater than in normal elliptical galaxies of similar optical magnitudes. The total emission-line luminosity is roughly half of the radio luminosity, and the radio luminosity correlates with the narrow-line luminosity over four decades. The near-nuclear emission-line gas is often distributed in a smooth, roughly elliptical feature, centered on and symmetric about the nucleus. The distribution of axial ratios found in these small emission-line nebulae (ELN) is inconsistent with them being disks seen from different orientations. The minor axes of the small regions of emission-line gas show only a weak tendency to align with the position angle of the extended radio source and the major axis of the stellar isophotes. The very extended emission line gas (d{sub neb} > 10 kpc) is filamentary and is found preferentially within the regions occupied by the radio source. The small (d{sub radio} < 100 kpc) radio sources with very extended ELN show evidence of interacting with their gas-rich environments; the large (d{sub radio} > 100 kpc) radio sources with very extended ELN show no signs that they have been disturbed by their surrounding media. Lower limits to the density of the emission line gas at distances of 10 kpc from the galaxy nucleus are {approximately}0.1 cm{sup {minus}3} and upper limits to the total mass in emission line gas are {approximately}10{sup 9} M {circle dot}. The optical nuclear continuum is strongly correlated with the narrow emission line luminosity and is sufficient to photoionize the ELN.

  16. Spectroscopy of an unusual emission line M star

    NASA Technical Reports Server (NTRS)

    Schneider, Donald P.; Greenstein, Jesse L.; Schmidt, Maarten; Gunn, James E.

    1991-01-01

    Moderate-resolution spectroscopy of an unusual late-type faint emission-line star, PC 0025 + 0047, is reported. A very strong (greater than 250 A equivalent width) an H-alpha emission line was detected by the present automated line search algorithm. The spectrum was found to have two unresolved emission lines (H-alpha and H-beta) near zero velocity, superposed on the absorption spectrum of a very red M dwarf which has strong K I, and relatively weak bands of TiO. From the weakness of the subordinate lines of Na I (8192 A) and other spectral features, it is inferred that it is definitely a cooler, and probably fainter, analog of LHS 2924. The strength of the emission lines indicates that PC 0025 + 0447 is very young and may be a fading predecessor brown drawf at an estimated M(bol) approaching 14m at a distance of about 60 pc.

  17. Emission line galaxies and active galactic nuclei in WINGS clusters

    NASA Astrophysics Data System (ADS)

    Marziani, P.; D'Onofrio, M.; Bettoni, D.; Poggianti, B. M.; Moretti, A.; Fasano, G.; Fritz, J.; Cava, A.; Varela, J.; Omizzolo, A.

    2017-03-01

    We present the analysis of the emission line galaxies members of 46 low-redshift (0.04 < z < 0.07) clusters observed by WINGS (WIde-field Nearby Galaxy cluster Survey). Emission line galaxies were identified following criteria that are meant to minimize biases against non-star-forming galaxies and classified employing diagnostic diagrams. We examined the emission line properties and frequencies of star-forming galaxies, transition objects, and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (≈ 10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of ≈1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms ofline equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks. The data whose description is provided in Table B.1, and emission line catalog of the WINGS database are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A83

  18. QtClassify: IFS data emission line candidates classifier

    NASA Astrophysics Data System (ADS)

    Kerutt, Josephine

    2017-03-01

    QtClassify is a GUI that helps classify emission lines found in integral field spectroscopic data. Input needed is a datacube as well as a catalog with emission lines and a signal-to-noise cube, such at that created by LSDCat (ascl:1612.002). The main idea is to take each detected line and guess what line it could be (and thus the redshift of the object). You would expect to see other lines that might not have been detected but are visible in the cube if you know where to look, which is why parts of the spectrum are shown where other lines are expected. In addition, monochromatic layers of the datacube are displayed, making it easy to spot additional emission lines.

  19. 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.

  20. 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.

  1. 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.

  2. Nebular Continuum and Line Emission in Stellar Population Synthesis Models

    NASA Astrophysics Data System (ADS)

    Byler, Nell; Dalcanton, Julianne J.; Conroy, Charlie; Johnson, Benjamin D.

    2017-05-01

    Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy. The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on Hα, and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H ii regions and star-forming galaxies. Our models show improved agreement with the observed H ii regions in the Ne iii/O ii plane and show satisfactory agreement with He ii emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

  3. Line emission in single-bubble sonoluminescence.

    PubMed

    Young, J B; Nelson, J A; Kang, W

    2001-03-19

    We report that single-bubble sonoluminescence (SBSL) at low light intensities produces emission bands similar to multibubble sonoluminescence (MBSL) for pure noble gas bubbles. A smooth crossover between SBSL and MBSL behavior can be induced by varying the acoustic pressure amplitude and thereby the intensity of the light emitted. The relative intensity of the band emission depends both on the molecular weight of the noble gas and the water temperature. Our results provide a connection between the mechanisms SBSL and MBSL and show that molecular emission plays a role in SBSL.

  4. Line Emission in Single-Bubble Sonoluminescence

    NASA Astrophysics Data System (ADS)

    Young, Joseph B.; Nelson, Jeffrey A.; Kang, Woowon

    2001-03-01

    We report that single-bubble sonoluminescence (SBSL) at low light intensities produces emission bands similar to multibubble sonoluminescence (MBSL) for pure noble gas bubbles. A smooth crossover between SBSL and MBSL behavior can be induced by varying the acoustic pressure amplitude and thereby the intensity of the light emitted. The relative intensity of the band emission depends both on the molecular weight of the noble gas and the water temperature. Our results provide a connection between the mechanisms SBSL and MBSL and show that molecular emission plays a role in SBSL.

  5. Synthesized Spectra of Optically Thin Emission Lines

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    In recent years realistic 3D numerical models of the solar atmosphere have become available. The models attempt to recreate the solar atmosphere and mimic observations in the best way, in order to make it possible to couple complicated observations with physical properties such as the temperatures, densities, velocities, and magnetic fields. We here present a study of synthetic spectra created using the Bifrost code in order to assess how well they fit with previously taken solar data. A study of the synthetic intensity, nonthermal line widths, Doppler shifts, and correlations between any two of these three components of the spectra first assuming statistical equilibrium is made, followed by a report on some of the effects nonequilibrium ionization will have on the synthesized spectra. We find that the synthetic intensities compare well with the observations. The synthetic observations depend on the assumed resolution and point-spread function (PSF) of the instrument, and we find a large effect on the results, especially for intensity and nonthermal line width. The Doppler shifts produce the reported persistent redshifts for the transition region (TR) lines and blueshifts for the upper TR and corona lines. The nonthermal line widths reproduce the well-known turnoff point around (2-3) × 105 K, but with much lower values than those observed. The nonthermal line widths tend to increase with decreasing assumed instrumental resolution, also when nonequilibrium ionization is included. Correlations between the nonthermal line width of any two TR line studies as reported by Chae et al. are reproduced, while the correlations of intensity to line width are reproduced only after applying a PSF to the data. Doppler shift correlations reported by Doschek for the TR lines and correlations of Doppler shift to nonthermal line width of the Fe xii 19.5 line reported by Doschek et al. are reproduced.

  6. Weak metallic emission lines in early B-type stars

    NASA Astrophysics Data System (ADS)

    Sadakane, Kozo; Nishimura, Masayoshi

    2017-06-01

    Previously unrecognized weak emission lines originating from high excitation states of Si II (12.84 eV) and Al II (13.08 eV) are detected in the red-region spectra of slowly rotating early B-type stars. We surveyed high-resolution spectra of 35 B-type stars covering spectral sub-types between B1 and B7 near the main sequence and found the emission line of Si II at 6239.6 Å in all of the 13 stars that have spectral sub-types B2 and B2.5. There are 17 stars belonging to sub-type B3 among which seven stars are found to show the emission line of Si II. The emission line of Al II at 6243.4 Å is detected in a narrower temperature range (Teff between 19000 K and 23000 K) in nine of the stars. Both emission lines are not detected in cooler (Teff < 16000 K) stars in our sample. The emission line of Si II at 6239.6 Å shows a single-peaked and symmetrical profile, and the line center has no shift in wavelength with respect to line centers of low excitation absorption lines of Si II. The measured half-width of the emission line is the same as those of rotationally broadened, low-excitation absorption lines of Si II. These observations imply that the emitting gas is not of circumstellar origin, but it is located at the outermost layer of the atmosphere covering the whole stellar surface, and corotates with the star.

  7. 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.

  8. 2D-model of oxygen emissions lines for Europa

    NASA Astrophysics Data System (ADS)

    Cessateur, Gaël; Barthelemy, Mathieu; Lilensten, Jean; Rubin, Martin; Maggiolo, Romain; De Keyser, Johan

    2017-04-01

    The Jovian moon Europa is an interesting case study as an archetype for icy satellites, and will be one of the primary targets of the ESA JUICE mission which should be launched in 2022. Hosting a thin neutral gas atmosphere mainly composed of O2 and H2O, Europa can be studied by its airglow and dayglow emissions. A 1D photochemistry model has first been developed to assess the impact of the solar UV flux on the visible emission, such as the red and green oxygen lines (Cessateur et al. 2016). For limb polar viewing, red line emissions can reach a few hundreds of Rayleigh close to the surface. The impact of the precipitating electrons has also been studied. The density and temperature of the electrons are first derived from the multifluid MHD model from Rubin et al. (2015). A 2D emission model has thus been developed to estimate the airglow emissions. When electrons are the major source of the visible emissions, the solar UV flux can be responsible for up to 15% of those emissions for some specific line of sight. Oxygen emission lines in the UV have also been considered, such as 130.5 and 135.6 nm. For the latter, we did estimate some significant line emissions reaching 700 Rayleigh for a polar limb viewing angle close to the surface. Oxygen emission lines are significant (higher than 10 R) for altitudes lower than 100 km for all lines, except for the red line emissions where emissions are still above 10 R up to 200 km from the surface. A sensitivity study has also been performed in order to assess the impact of the uncertainties relative to the dissociative-excitation cross sections. Cessateur G, Barthelemy M & Peinke I. Photochemistry-emission coupled model for Europa and Ganymede. J. Space Weather Space Clim., 6, A17, 2016 Rubin, M., et al. Self-consistent multifluid MHD simulations of Europa's exospheric interaction with Jupiter's magnetosphere, J. Geophys. Res. Space Physics, 120, 3503-3524, 2015

  9. 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.

  10. Microlensing Effects on Emission Lines from Homologously Expanding Winds

    NASA Astrophysics Data System (ADS)

    Ignace, R.; Bryce, H. M.; Hendry, M. A.

    2004-12-01

    We have been investigating the influence of microlensing on a variety of spectroscopic signatures relevant to circumstellar flows. Here we report on recent results for line profiles that form in spherically symmetric winds during a microlensing event. As a convenient test case, we have adopted a homologous velocity law (v ∝ r, from r=Rphot to rmax). Results are discussed for resonance scattering P Cygni lines and recombination emission lines. Somewhat surprisingly, the rectified line profiles show rather mild variations in response to microlensing. The reason is that both the line emission from the extended wind and the stellar photosphere are lensed, so that the strong magnification effects of lensing seen in either component are partially supressed when showing the continuum normalized spectrum (which is the common form of display for such data). Still, significant and observable variations in the line equivalent width do result. This research has been supported in part by NSF grant AST-0354261.

  11. 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.

  12. 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.

  13. TEMPERATURE DEPENDENCE OF LINE STRUCTURE OF CADMIUM SULFIDE EDGE EMISSION

    DTIC Science & Technology

    The temperature dependence of the line structure in Cds edge emission stimulated by UV light was investigated from 4.2 K to 367 K. The spectral... dependence of the primary line groups is a linear function of temperature above 220 K with coefficients of change of 1.27 and 1.8 Angstroms degree K for the...lines observed. Below 220 K the dependence departs from linearity and approaches its limiting value more rapidly with decreasing temperature

  14. The emission line sequence of normal spiral galaxies

    NASA Astrophysics Data System (ADS)

    Sodré, L., Jr.; Stasińska, G.

    1999-05-01

    We have analyzed the emission line properties in the integrated spectra of 15 normal spiral galaxies. We show that very clear trends appear when plotting relevant emission line ratios or equivalent widths as a function of galaxy spectral types, obtained with a Principal Component Analysis of the continua and absorption features of spectra. The equivalent widths of all the lines analyzed correlate extremely well with spectral types, implying that each of them can be considered a good indicator of the spectral type in normal galaxies. The position of most galaxies of our sample in classical emission line diagnostic diagrams follows that of individual giant HII regions in spiral galaxies, but for the earliest type galaxies, the emission line pattern resembles more that of LINERs. Therefore, the direct interpretation of equivalent widths in terms of star formation rates would be misleading in such cases. The observed trends in the emission line ratios as a function of galaxy spectral type suggest a decrease of O/H, a decrease of N/O, an increase of the average effective temperature or ionization parameter, and a decrease of the effective internal extinction of galaxies with increasing (early to late) spectral type.

  15. 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

  16. 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.

  17. The Emission-Line Spectrum of KUG 1031+398 and the Intermediate Line Region Controversy

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. C.; Véron, P.; Véron-Cetty, M.-P.

    We present results based on the analysis of optical spectra of the Narrow-Line Seyfert 1 (NLS1) galaxy KUG 1031+398, for which evidence was reported of a line-emitting region "intermediate" (both in terms of velocity and density) between the conventional Broad and Narrow Line Regions (BLR and NLR, respectively). From our observations and modeling of the spectra, we get a consistent decomposition of the line profiles into four components: an extended H II region with unresolved lines, two distinct Seyfert-type clouds identified with the NLR, and a relatively narrow "broad line" component emitting only Balmer lines but no forbidden lines. Therefore, although we find this object to be exceptional in having line-emission from the BLR with almost the same width as the narrow lines, our interpretation of the data does not support the existence of an "intermediate" line region (ILR).

  18. 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.

  19. 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.

  20. 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.

  1. Perfect Thermal Emission by Nanoscale Transmission Line Resonators.

    PubMed

    Liu, Baoan; Gong, Wei; Yu, Bowen; Li, Pengfei; Shen, Sheng

    2017-02-08

    Thermal radiation with a narrow-band emission spectrum is of great importance in a variety of applications such as infrared sensing, thermophotovoltaics, radiation cooling, and thermal circuits. Although resonant nanophotonic structures such as metamaterials and nanocavities have been demonstrated to achieve the narrow-band thermal emission, maximizing their radiation power toward perfect emission still remains challenging. Here, based on the recently developed quasi-normal mode theory, we prove that thermal emission from a nanoscale transmission line resonator can always be maximized by tuning the waveguiding loss of the resonator or bending the structure. By use of nanoscale transmission line resonators as basic building blocks, we experimentally demonstrate a new type of macroscopic perfect and tunable thermal emitters. Our experimental demonstration in conjunction with the general theoretical framework from the quasi-normal mode theory lays the foundation for designing tunable narrow-band thermal emitters with applications in thermal infrared light sources, thermal management, and infrared sensing and imaging.

  2. Community-LINE Source Model (C-LINE) to estimate roadway emissions

    EPA Pesticide Factsheets

    C-LINE is a web-based model that estimates emissions and dispersion of toxic air pollutants for roadways in the U.S. This reduced-form air quality model examines what-if scenarios for changes in emissions such as traffic volume fleet mix and vehicle speed.

  3. 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.

  4. The origin of the broad line emission from Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Shields, G. A.

    1977-01-01

    Mass loss from an accretion disk around a supermassive (of the order of 100 million solar masses) black hole is proposed as the origin of the broad permitted lines of Seyfert galaxies and QSOs. The material is expelled by ionizing radiation emitted near the center of the disk and striking it at a radius of approximately 10 to the 16.5 power cm. The escaping gas initially has a density of about 1 trillion per cu cm, high enough for radiation pressure to accelerate the gas to high radial velocities. The model leads to line emission from tiny dense filaments moving at about 10,000 km/s in a region roughly 10 to the 17th power cm across. This agrees with the observed broad line widths, variability time scales, and the absence of broad forbidden-line emission.

  5. The unusual emission line spectrum of I Zw 1

    NASA Astrophysics Data System (ADS)

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

    2004-04-01

    Most Seyfert 1 galaxies show strong Fe II lines in their spectrum having the velocity and width of the broad emission lines. To remove the Fe II contribution in these objects, an accurate template is necessary. We used very high signal-to-noise, medium resolution archive optical spectra of I Zw 1 to build such a template. I Zw 1 is a bright narrow-line Seyfert 1 galaxy. As such it is well suited for a detailed analysis of its emission line spectrum. Furthermore it is known to have a very peculiar spectrum with, in addition to the usual broad and narrow line regions, two emission regions emitting broad and blue shifted [O III] lines making it a peculiarly interesting object. While analysing the spectra, we found that the narrow-line region is, unlike the NLR of most Seyfert 1 galaxies, a very low excitation region dominated by both permitted and forbidden Fe II lines. It is very similar to the emission spectrum of a blob in η Carinae which is a low temperature (Te˜6500 K), relatively high density (Ne= 106 cm-3) cloud. The Fe II lines in this cloud are mainly due to pumping via the stellar continuum radiation field (Verner et al. \\cite{verner02}). We did not succeed in modelling the spectrum of the broad-line region, and we suggest that a non radiative heating mechanism increases the temperature in the excited H I region, thus providing the necessary additional excitation of the Fe II lines. For the low-excitation narrow-line region, we are able to apply boundaries to the physical conditions accounting for the forbidden and permitted Fe II lines (106lines} and \\ref{N3} are only available in electronic form at http://www.edpsciences.org Figure 8 is 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/417/515

  6. Emission-line spectra of circumstellar envelopes - Infrared hydrogen line fluxes from Be stars

    NASA Astrophysics Data System (ADS)

    Persson, S. E.; McGregor, P. J.

    1985-09-01

    Fluxes for eight H I emission lines between 1.28 and 4.67 μm are presented for a sample of seven Be stars. Brα fluxes are given for six additional Be stars. The H I line ratios form the basis for an observational test of models for emission from circumstellar shells that have a range of Brα optical depths well in excess of unity. Enough data on optically thick H I, Ca II, and O I line strengths of circumstellar envelope stars now exist that it should be possible to place detailed radiative-transfer calculations of optically thick envelope emission on a secure observational footing. Comparisons of line ratios with the models by Simon et al. for infrared line emission from stellar winds show promise. The Be star H I line ratios can also be compared with similar data for deeply dust-embedded young stellar objects. These enigmatic objects display stronger H I lines per unit luminosity than the Be stars, but share similar overall envelope physical conditions. Several infrared line ratios are examined to lay the groundwork for extinction determinations and guidelines for radiative-transfer models.

  7. 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.

  8. 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.

  9. 2D forbidden oxygen line emission maps for various comets

    NASA Astrophysics Data System (ADS)

    Cessateur, Gaël; De Keyser, Johan; Maggiolo, Romain; Rubin, Martin; Gronoff, Guillaume; Gibbons, Andrew; Jehin, Emmanuel; Dhooghe, Frédéric; Gunell, Herbert; Vaeck, Nathalie; Loreau, Jérôme

    2017-04-01

    We present here a photochemical model for oxygen line emissions for various comets at 577.7 nm (green line), 630 nm, and 636.4 nm (red-doublet). The in-situ detection of molecular oxygen by Rosetta (67P/Churyumov-Gerasimenko) and Giotto (1P/Halley) makes an update of the usual photochemical model of oxygen line emissions necessary. As the water production rate is increasing, a 2D approach becomes more suitable rather than the usual 1D approach. Indeed, for very active comets such as 1P/Halley or C/1995 O1 Hale-Bopp, neutral densities are high enough to fully absorb the solar UV flux. The resulting 2D emission maps then do not have a spherical symmetry, and become thus interesting tools to be compared with in-situ and/or ground based observations. One major problem relative to the photochemical models lies in the cross section uncertainties. Based on a Monte-Carlo approach, we have assessed the impact of the uncertainties of the dissociation cross section of the neutral species on the resulting oxygen lines emissions.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Excitation of oxygen permitted line emissions in the tropical nightglow.

    NASA Technical Reports Server (NTRS)

    Tinsley, B. A.; Christensen, A. B.; Bittencourt, J.; Gouveia, H.; Angreji, P. D.; Takahashi, H.

    1973-01-01

    The ultraviolet oxygen emissions at 1304 and 1356 A in the tropical nightglow seen from Ogo 4 by Hicks and Chubb (1970) and Barth and Schaffner (1970) are accompanied by emission at 7774 and 4368 A, which have been studied from the ground by looking through the beam of an ionosonde operated under the Appleton anomaly ionization peaks. Simultaneous forbidden O I 6300-A measurements were also made. A theoretical value for the partial rate coefficient for 7774 emission by radiative recombination has been obtained, and from the ionospheric data and a model atmosphere the expected rates of radiative recombination and ion-ion recombination were calculated. The time variations and absolute intensity of the calculated and observed intensities agree reasonably well, when the uncertainties involved are considered. It is concluded that radiative recombination is the major source of the tropical oxygen permitted line emissions, accompanied by a small contribution from ion-ion recombination.

  15. 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.

  16. 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.

  17. Radiative Transfer Effects in He I Emission Lines

    NASA Astrophysics Data System (ADS)

    Benjamin, Robert A.; Skillman, Evan D.; Smits, Derck P.

    2002-04-01

    We consider the effect of optical depth of the 23S level on the nebular recombination spectrum of He I for a spherically symmetric nebula with no systematic velocity gradients. These calculations, using many improvements in atomic data, can be used in place of the earlier calculations of Robbins. We give representative Case B line fluxes for UV, optical, and IR emission lines over a range of physical conditions: T=5000-20,000 K, ne=1-108 cm-3, and τ3889=0-100. A FORTRAN program for calculating emissivities for all lines arising from quantum levels with n<=10 is also available from the authors. We present a special set of fitting formulae for the physical conditions relevant to low-metallicity extragalactic H II regions: T=12,000-20,000 K, ne=1-300 cm-3, and τ3889<2.0). For this range of physical conditions, the Case B line fluxes of the bright optical lines 4471 Å, 5876 Å, and 6678 Å, are changed less than 1%, in agreement with previous studies. However, the 7065 Å corrections are much smaller than those calculated by Izotov & Thuan based on the earlier calculations by Robbins. This means that the 7065 Å line is a better density diagnostic than previously thought. Two corrections to the fitting functions calculated in our previous work are also given.

  18. 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.

  19. 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.

  20. Measurement of the deuterium Balmer series line emission on EAST

    SciTech Connect

    Wu, C. R.; Xu, Z.; Jin, Z.; Zhang, P. F.; Huang, J. Gao, W.; Gao, W.; Chang, J. F.; Xu, J. C.; Duan, Y. M.; Chen, Y. J.; Zhang, L.; Wu, Z. W.; Li, J. G.; Hou, Y. M.

    2016-11-15

    Volume recombination plays an important role towards plasma detachment for magnetically confined fusion devices. High quantum number states of the Balmer series of deuterium are used to study recombination. On EAST (Experimental Advanced Superconducting Tokamak), two visible spectroscopic measurements are applied for the upper/lower divertor with 13 channels, respectively. Both systems are coupled with Princeton Instruments ProEM EMCCD 1024B camera: one is equipped on an Acton SP2750 spectrometer, which has a high spectral resolution ∼0.0049 nm with 2400 gr/mm grating to measure the D{sub α}(H{sub α}) spectral line and with 1200 gr/mm grating to measure deuterium molecular Fulcher band emissions and another is equipped on IsoPlane SCT320 using 600 gr/mm to measure high-n Balmer series emission lines, allowing us to study volume recombination on EAST and to obtain the related line averaged plasma parameters (T{sub e}, n{sub e}) during EAST detached phases. This paper will present the details of the measurements and the characteristics of deuterium Balmer series line emissions during density ramp-up L-mode USN plasma on EAST.

  1. Measurement of the deuterium Balmer series line emission on EAST

    NASA Astrophysics Data System (ADS)

    Wu, C. R.; Huang, J.; Gao, W.; Gao, W.; Xu, Z.; Chang, J. F.; Hou, Y. M.; Jin, Z.; Xu, J. C.; Duan, Y. M.; Zhang, P. F.; Chen, Y. J.; Zhang, L.; Wu, Z. W.; Li, J. G.

    2016-11-01

    Volume recombination plays an important role towards plasma detachment for magnetically confined fusion devices. High quantum number states of the Balmer series of deuterium are used to study recombination. On EAST (Experimental Advanced Superconducting Tokamak), two visible spectroscopic measurements are applied for the upper/lower divertor with 13 channels, respectively. Both systems are coupled with Princeton Instruments ProEM EMCCD 1024B camera: one is equipped on an Acton SP2750 spectrometer, which has a high spectral resolution ˜0.0049 nm with 2400 gr/mm grating to measure the Dα(Hα) spectral line and with 1200 gr/mm grating to measure deuterium molecular Fulcher band emissions and another is equipped on IsoPlane SCT320 using 600 gr/mm to measure high-n Balmer series emission lines, allowing us to study volume recombination on EAST and to obtain the related line averaged plasma parameters (Te, ne) during EAST detached phases. This paper will present the details of the measurements and the characteristics of deuterium Balmer series line emissions during density ramp-up L-mode USN plasma on EAST.

  2. 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

  3. 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.

  4. DISCOVERY OF POLARIZED LINE EMISSION IN SN 1006

    SciTech Connect

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

    2015-12-10

    Laming predicted that the narrow Balmer line core of the ∼3000 km s{sup −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.

  5. 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.

  6. The role of UV bump in line emission

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Luc, Binette; Fang, Li-Zhi

    1992-05-01

    It is suggested that the UV bump which the low-ionization lines of the Seyfert galaxy Fairall 9 follow has a shape more complicated than a simple blackbody curve and has a rather steep drop around 30 eV. The degree of luminosity dependence of the equivalent width of Ly-alpha, semiforbidden Si IV, and C IV is inversely correlated with an individual emission line's ionization level. This explains why only the C IV equivalent width exhibits a significant luminosity dependence (the Baldwin effect).

  7. Sharp intense line in the bioluminescence emission of the firefly.

    PubMed

    Barua, A Gohain; Sharma, U; Phukan, M; Hazarika, S

    2014-06-01

    Numerous investigations have been carried out on the spectral distribution of the light of different species of fireflies. Here we record the emission spectrum of the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae) on a color film. Green and red color-sectors, with an intense yellow one in between, appear in this spectrum. Intensity profile of this spectrum reveals a hitherto undetected strong narrow yellow line, which lies within the full-width-at-half maximum (FWHM) of the intensity profile. The spectrum recorded in a high-resolution spectrometer confirms the presence of this sharp intense line. This finding lends support to an earlier drawn analogy between the in vivo emission of the firefly and laser light.

  8. The emission-line spectrum of KUG 1031+398 and the intermediate line region

    NASA Astrophysics Data System (ADS)

    Gonçalves, A. C.; Véron, P.; Véron-Cetty, M.-P.

    1999-01-01

    We present results based on the analysis of optical spectra of KUG 1031+398, a Narrow Line Seyfert 1 (NLS1) galaxy for which Mason et al. (1996) reported evidence for a line-emitting region ``intermediate'' (both in terms of velocity and density) between the conventional broad and narrow line regions (BLR and NLR, respectively). From our observations and modelling of the spectra, we get a consistent decomposition of the line profiles into four components: an extended H Ii region with unresolved lines, two distinct Seyfert-type clouds identified with the NLR, and a relatively narrow ``broad line'' component emitting only Balmer lines but no forbidden lines. Therefore, and although we find this object to be exceptional in having line-emission from the BLR with almost the same width as the narrow lines, our interpretation of the data does not support the existence of an ``intermediate'' line region (ILR). Based on observations collected at the Observatoire de Haute-Provence (CNRS), France.

  9. Radio emission and the forbidden line region of Seyfert galaxies

    SciTech Connect

    Ulvestad, J.S.

    1981-01-01

    The results of an extensive program of mapping Seyfert galaxies using the Very Large Array radio telescope are presented. Unlike the majority of radio galaxies, the radio emission in most Seyferts is confined to the inner few kiloparsecs (or less) of the galaxy. This scale is similar to the size of the region in which optical forbidden line emission occurs. Six double (or triple) radio sources have been mapped now in Seyfert galaxies. Approximately ten more galaxies shown more diffuse emission or are resolved only slightly. In almost all galaxies, the central radio peak, when present, coincides with the optical continuum peak. In every double or triple radio source, the outer radio lobes straddle that optical peak. The major axes of the double and triple radio sources may be correlated with the directions of greatest elongation of the optical line-emitting cloud complexes. However, the radio source axes do not appear to be related to the major or minor axes of the outer optical continuum isophotes of the Seyfert galaxies. Synchrotron emission is the dominant source of radio photons in all the galaxies observed. Thermal processes contribute, on the average, no more than about 6% of the total radio emission at 4.885 GHz. Using standard assumptions, radio luminosities, magnetic fields, and total energy contents have been calculated for the observed galaxies. The triple radio source in NGC 5548 has been studied in detail. The properties of NGC 5548 have been used to investigate some theoretical aspects of the double and triple sources and their relationship to the forbidden line region (FLR).

  10. 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.

  11. The Redshifted Excess in Quasar C IV Broad Emission Lines

    NASA Astrophysics Data System (ADS)

    Punsly, Brian

    2010-04-01

    In this paper, the Evans and Koratkar Atlas of Hubble Space Telescope Faint Object Spectrograph Spectra of Active Galactic Nuclei and Quasars is used to study the redward asymmetry in C IV broad emission lines (BELs). It is concluded that there is a highly significant correlation between the spectral index from 10 GHz to 1350 Å and the amount of excess luminosity in the red wing of the C IV BEL (>99.9999% significance level for the full sample and the radio-loud subsample independently, but no correlation is found for the radio-quiet subsample). This is interpreted as a correlation between radio core dominance and the strength of the C IV redward asymmetry. The data imply that within the quasar environment there is BEL gas with moderately blueshifted emission associated with the purely radio-quiet quasar (RQQ) phenomenon (the accretion disk), and the radio jet emission mechanism is associated with a redward BEL component that is most prominent for lines of sight along the jet axis. Thus, RQQs have C IV BELs that tend to show blueshifted excess, and radio-loud quasars show either a red or blue excess with the tendency for a dominant red excess increasing as the line-of-sight approaches the jet axis.

  12. Neutral Hydrogen and Its Emission Lines in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Vial, Jean-Claude; Chane-Yook, Martine

    2016-12-01

    Since the Lyman-α rocket observations of Gabriel ( Solar Phys. 21, 392, 1971), it has been realized that the hydrogen (H) lines could be observed in the corona and that they offer an interesting diagnostic for the temperature, density, and radial velocity of the coronal plasma. Moreover, various space missions have been proposed to measure the coronal magnetic and velocity fields through polarimetry in H lines. A necessary condition for such measurements is to benefit from a sufficient signal-to-noise ratio. The aim of this article is to evaluate the emission in three representative lines of H for three different coronal structures. The computations have been performed with a full non-local thermodynamic-equilibrium (non-LTE) code and its simplified version without radiative transfer. Since all collisional and radiative quantities (including incident ionizing and exciting radiation) are taken into account, the ionization is treated exactly. Profiles are presented at two heights (1.05 and 1.9 solar radii, from Sun center) in the corona, and the integrated intensities are computed at heights up to five solar radii. We compare our results with previous computations and observations ( e.g. Lα from Ultraviolet Coronal Spectrometer) and find a rough (model-dependent) agreement. Since the Hα line is a possible candidate for ground-based polarimetry, we show that in order to detect its emission in various coronal structures, it is necessary to use a very narrow (less than 2 Å wide) bandpass filter.

  13. Reverberation Mapping of Optical Emission Lines in Five Active Galaxies

    NASA Astrophysics Data System (ADS)

    Fausnaugh, M. M.; Grier, C. J.; Bentz, M. C.; Denney, K. D.; De Rosa, G.; Peterson, B. M.; Kochanek, C. S.; Pogge, R. W.; Adams, S. M.; Barth, A. J.; Beatty, Thomas G.; Bhattacharjee, A.; Borman, G. A.; Boroson, T. A.; Bottorff, M. C.; Brown, Jacob E.; Brown, Jonathan S.; Brotherton, M. S.; Coker, C. T.; Crawford, S. M.; Croxall, K. V.; Eftekharzadeh, Sarah; Eracleous, Michael; Joner, M. D.; Henderson, C. B.; Holoien, T. W.-S.; Horne, Keith; Hutchison, T.; Kaspi, Shai; Kim, S.; King, Anthea L.; Li, Miao; Lochhaas, Cassandra; Ma, Zhiyuan; MacInnis, F.; Manne-Nicholas, E. R.; Mason, M.; Montuori, Carmen; Mosquera, Ana; Mudd, Dale; Musso, R.; Nazarov, S. V.; Nguyen, M. L.; Okhmat, D. N.; Onken, Christopher A.; Ou-Yang, B.; Pancoast, A.; Pei, L.; Penny, Matthew T.; Poleski, Radosław; Rafter, Stephen; Romero-Colmenero, E.; Runnoe, Jessie; Sand, David J.; Schimoia, Jaderson S.; Sergeev, S. G.; Shappee, B. J.; Simonian, Gregory V.; Somers, Garrett; Spencer, M.; Starkey, D. A.; Stevens, Daniel J.; Tayar, Jamie; Treu, T.; Valenti, Stefano; Van Saders, J.; Villanueva, S., Jr.; Villforth, C.; Weiss, Yaniv; Winkler, H.; Zhu, W.

    2017-05-01

    We present the first results from an optical reverberation mapping campaign executed in 2014 targeting the active galactic nuclei (AGNs) MCG+08-11-011, NGC 2617, NGC 4051, 3C 382, and Mrk 374. Our targets have diverse and interesting observational properties, including a “changing look” AGN and a broad-line radio galaxy. Based on continuum-Hβ lags, we measure black hole masses for all five targets. We also obtain Hγ and He ii λ4686 lags for all objects except 3C 382. The He ii λ4686 lags indicate radial stratification of the BLR, and the masses derived from different emission lines are in general agreement. The relative responsivities of these lines are also in qualitative agreement with photoionization models. These spectra have extremely high signal-to-noise ratios (100-300 per pixel) and there are excellent prospects for obtaining velocity-resolved reverberation signatures.

  14. Absorption lines of {sup 127}I{sub 2} in the vicinity of emission lines of metal vapors

    SciTech Connect

    Mironov, A.V.; Privalov, V.E.; Savel`ev, S.K.

    1995-03-01

    Some details of the absorption spectrum of {sup 127}I{sub 2} in the vicinity of emission lines of selenium, cadmium, mercury, tin, and zinc are refined. Seventeen emission lines that are most free of the effect of overlap with the weaker absorption lines are revealed. 8 refs., 1 fig., 2 tabs.

  15. Molecular cloud photoevaporation and far-infrared line emission

    NASA Astrophysics Data System (ADS)

    Vallini, L.; Ferrara, A.; Pallottini, A.; Gallerani, S.

    2017-05-01

    With the aim of improving predictions on far-infrared (FIR) line emission from Giant Molecular Clouds (GMCs), we study the effects of photoevaporation (PE) produced by external far-ultraviolet (FUV) and ionizing (extreme-ultraviolet) radiation on GMC structure. We consider three different GMCs with mass in the range MGMC = 103-106 M⊙. Our model includes (i) an observationally based inhomogeneous GMC density field, and (ii) its time evolution during the PE process. In the fiducial case (MGMC ≈ 105 M⊙), the PE time (tpe) increases from 1 to 30 Myr for gas metallicity Z = 0.05-1 Z⊙, respectively. Next, we compute the time-dependent luminosity of key FIR lines tracing the neutral and ionized gas layers of the GMCs, ([C ii] at 158 μm, [O iii] at 88 μm) as a function of G0, and Z until complete PE at tpe. We find that the specific [C ii] luminosity is almost independent of the GMC model within the survival time of the cloud. Stronger FUV fluxes produce higher [C ii] and [O iii] luminosities, however, lasting for progressively shorter times. At Z = Z⊙, the [C ii] emission is maximized (L_{C II} ≈ 10^4 {L_{{⊙}}} for the fiducial model) for t < 1 Myr and log G0 ≥ 3. Noticeably, and consistently with the recent detection by Inoue et al. of a galaxy at redshift z ≈ 7.2, for Z ≤ 0.2 Z⊙, the [O iii] line might outshine [C ii] emission by up to ≈1000 times. We conclude that the [O iii] line is a key diagnostic of low-metallicity interstellar medium, especially in galaxies with very young stellar populations.

  16. Emission Line Ratios of FE III as Astrophysical Plasma Diagnostics

    NASA Astrophysics Data System (ADS)

    Laha, Sibasish; Tyndall, Niall B.; Keenan, Francis P.; Ballance, Connor P.; Ramsbottom, Catherine A.; Ferland, Gary J.; Hibbert, Alan

    2017-05-01

    Recent, state-of-the-art calculations of A-values and electron impact excitation rates for Fe iii are used in conjunction with the Cloudy modeling code to derive emission-line intensity ratios for optical transitions among the fine-structure levels of the 3d6 configuration. A comparison of these with high-resolution, high signal-to-noise spectra of gaseous nebulae reveals that previous discrepancies found between theory and observation are not fully resolved by the latest atomic data. Blending is ruled out as a likely cause of the discrepancies, because temperature- and density-independent ratios (arising from lines with common upper levels) match well with those predicted by theory. For a typical nebular plasma with electron temperature {T}{{e}}=9000 K and electron density {N}{{e}}={10}4 {{cm}}-3, cascading of electrons from the levels {}3{{{G}}}5, {}3{{{G}}}4 and {}3{{{G}}}3 plays an important role in determining the populations of lower levels, such as {}3{{{F}}}4, which provide the density diagnostic emission lines of Fe iii, such as {}5{{{D}}}4 - {}3{{{F}}}4 at 4658 Å. Hence, further work on the A-values for these transitions is recommended, ideally including measurements if possible. However, some Fe iii ratios do provide reliable {N}{{e}}-diagnostics, such as 4986/4658. The Fe iii cooling function, calculated with Cloudy using the most recent atomic data, is found to be significantly greater at T e ≃ 30,000 K than predicted with the existing Cloudy model. This is due to the presence of additional emission lines with the new data, particularly in the 1000-4000 Å wavelength region.

  17. Intensity Mapping with Carbon Monoxide Emission Lines and the Redshifted 21 cm Line

    NASA Astrophysics Data System (ADS)

    Lidz, Adam; Furlanetto, Steven R.; Oh, S. Peng; Aguirre, James; Chang, Tzu-Ching; Doré, Olivier; Pritchard, Jonathan R.

    2011-11-01

    We quantify the prospects for using emission lines from rotational transitions of the CO molecule to perform an "intensity mapping" observation at high redshift during the Epoch of Reionization (EoR). The aim of CO intensity mapping is to observe the combined CO emission from many unresolved galaxies, to measure the spatial fluctuations in this emission, and to use this as a tracer of large-scale structure at very early times in the history of our universe. This measurement would help determine the properties of molecular clouds—the sites of star formation—in the very galaxies that reionize the universe. We further consider the possibility of cross-correlating CO intensity maps with future observations of the redshifted 21 cm line. The cross spectrum is less sensitive to foreground contamination than the auto power spectra, and can therefore help confirm the high-redshift origin of each signal. Furthermore, the cross spectrum measurement would help extract key information about the EoR, especially regarding the size distribution of ionized regions. We discuss uncertainties in predicting the CO signal at high redshift, and discuss strategies for improving these predictions. Under favorable assumptions and feasible specifications for a CO survey mapping the CO(2-1) and CO(1-0) lines, the power spectrum of CO emission fluctuations and its cross spectrum with future 21 cm measurements from the Murchison Widefield Array are detectable at high significance.

  18. The Emission Line Spectrum of SN 1987A

    NASA Astrophysics Data System (ADS)

    Li, Hongwei

    With Supernova 1987A (SN 1987A) we have an unprecedented view of the optical and infrared spectrum of a supernova. Here, we develop the basic theory to describe the emission line spectrum of a supernova in the nebular phase and we apply this theory to three of the most prominent important emission line systems: the (OI) lambda lambda 6300, 6364 doublet; the (Ca II) lambda lambda 7300 and Ca II lambda lambda 8600 system, and the optical and infrared lines of Fe, Co and Ni. As a first example, we analyze the evolution of the (OI) lambda lambda 6300, 6364 doublet. We find that the ratio of the mass of OI to its filling factor, M_{rm O}/f_{rm O} , must be about 11, so that for a reasonable value of M_{rm O} = 1.3 Modot, f _{rm O} ~ 0.12. Second, we analyze the near-infrared emission lines of Ca II. We find that UV pumping is required for t _sp{~}> 350 days to fit the (Ca II) lambda lambda 7300 and Ca II lambda lambda 8600 lines. Moreover, we find that the Ca II lines came from the primordial gas rather than the freshly nucleosynthesised products. Iron, cobalt and nickel lines are extremely important in understanding the physical processes in the envelope of SN 1987A. Radioactive decays of ^{56 }Co, 57Co, 44Ti and ^ {22}Na are the dominant energy sources of radiation of SN 1987A in the nebular phase. We find that the nickel-cobalt-iron clumps must have expanded by a factor ~30 or more during a few weeks after outburst as a result of heating by 56Ni and ^{56 }Co decay. This expansion leads to a large filling factor of iron clumps, f_{ rm Fe}~ 0.5, and a small filling factor, f_{rm H,He}~ 0.1-0.2, for primordial gas, such as H, He, etc. From the conditions of thermal equilibrium and ionization equilibrium we determine the evolution of temperature and ionization of the iron clumps. We can account for the light curves (for 150 days_sp ~> t_sp ~> 2 yr) of almost all the observed emission lines of Fe I, Fe II, Co I, Co II, Ni I and Ni II within the uncertainties in

  19. 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

  20. 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.

  1. 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.

  2. Molecular line emission models of Herbig-Haro objects. II - HCO(+) emission

    NASA Technical Reports Server (NTRS)

    Wolfire, Mark G.; Koenigl, Arieh

    1993-01-01

    We present time-dependent models of the chemistry and temperature of interstellar molecular gas clumps that are exposed to the radiation from propagating stellar-jet shocks. The X-ray, EUV, and FUV radiation from the shock initiates ion chemistry and also heats the gas in the clumps. Using representative parameters, we show that, on the shock transit time between the clumps, the abundances of the ionized molecular species that are produced in the clumps can exceed the values determined from steady state models by several orders of magnitude. Collisional excitation by the heated gas can lead to measurable line emission from several ionized species; as in previous investigations of X-ray-irradiated molecular gas, we find that electron impacts contribute significantly to this process. We apply these results to the interpretation of the HCO(+) line emission that has already been detected in several Herbig-Haro objects. We demonstrate that this picture provides a natural explanation of the fact that the line intensity typically peaks ahead of the associated shock, as well as of the reported low line-center velocities and narrow line widths. We tabulate several diagnostic line intensities of HCO(+) and other molecular species that may be used to infer the physical conditions in the emitting gas.

  3. 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

  4. Emission-line galaxies in the Slice of the Universe

    NASA Technical Reports Server (NTRS)

    Salzer, John J.; Aldering, Gregory S.; Bothun, Gregory D.; Mazzarella, Joseph M.; Lonsdale, Carol J.

    1988-01-01

    The relative spatial distributions of emission-line galaxies (ELGs) and normal galaxies that lie in the sky area covered by the 'Slice' survey (de Lapparent et al., 1986) are considered. ELGs follow the same spatial distribution as found for the Slice galaxies, with the exception that they avoid the Coma cluster. It is pointed out that although the present ELGs are not shown to occur in regions of very low density, the luminosity distribution of the sample is such that luminosity/mass-dependent effects on the spatial distribution would not be noticeable.

  5. Plasma turbulence and impulsive UV line emission in solar flares

    NASA Technical Reports Server (NTRS)

    Brown, John C.

    1986-01-01

    Observations show that hard X-ray burst and UV lines rise and fall simultaneously on time scales of seconds. Hydrodynamic simulations of beam-heated atmospheres, based on collisional transport, however, produce only a gradual fall in UV emission, when the beam flux falls, due to the long time scale of conductive relaxation. It is suggested that this discrepancy might be explained by onset of plasma turbulence driven by the strong heat flux or by the beam return current going unstable. Such turbulence greatly reduces electrical and thermal conductivities. Fall in electrical conductivity reduces the hard X-ray flux by enhanced ohmic dissipation of the return current, while fall in thermal conductivity may cause the UV line to fall by reducing the transition region thickness.

  6. Far-Infrared Line Emission from Collapsing Protostellar Envelopes

    NASA Astrophysics Data System (ADS)

    Ceccarelli, Cecilia; Hollenbach, David J.; Tielens, Alexander G. G. M.

    1996-11-01

    We present a theoretical model that computes the chemical evolution, thermal balance, and line emission from the collapsing gas of the envelopes that surround protostars. This is the first attempt to calculate self-consistently the line spectrum from the infalling gas with a model that includes dynamics, chemistry, heating and cooling, and radiative transfer. For the dynamics, we have adopted the Shu "inside-out" spherical collapse of an isothermal cloud valid for r ≥ rc, where the centrifugal radius rc ˜1014-1015 cm. A time-dependent chemical code follows the chemical composition of the envelope during the collapse. The main chemical result is that the inner regions (r ≤ 1O15 cm) have high H2O abundances caused by the evaporation of H2O ice from grains when dust temperatures exceed ˜100 K and by gas-phase chemical reactions when gas temperatures exceed ˜200 K. The gas is heated mainly by absorption of (dust continuum) near-infrared (NIR) photons by H2O molecules in the inner regions, by compressional heating in an intermediate zone, and by collisions of gas with warm dust grains in the outer regions (r ≥ 1O17 cm). The gas is cooled by H2 Orotational lines in the inner regions, by the [O I] 63 μm fine-structure line and CO rotational lines in the intermediate region, and by CO rotational lines in the outer zones. The gas temperature roughly tracks the grain temperature for 1O14 cm ≤ r ≤ 1O17 cm, ranging from about 300 K to 1O K. We present the computed spectrum of a 1 Msun protostar accreting at a rate of 1O-5 Msun yr-1. The H2O lines and the [O I] 63 μm line will be easily detectable by the spectrometers on board the Infrared Space Observatory (ISO). The [O I] 63 μm line and the mid J (J ˜ 7-15) CO lines can be detected by the Kuiper Airborne Observatory (KAO) or the Stratospheric Observatory For Infrared Astronomy (SOFIA), and certain low-J CO lines can be detected by ground-based telescopes. We present also a large number of other models in

  7. Linearized spectrum correlation analysis for line emission measurements

    NASA Astrophysics Data System (ADS)

    Nishizawa, T.; Nornberg, M. D.; Den Hartog, D. J.; Sarff, J. S.

    2017-08-01

    A new spectral analysis method, Linearized Spectrum Correlation Analysis (LSCA), for charge exchange and passive ion Doppler spectroscopy is introduced to provide a means of measuring fast spectral line shape changes associated with ion-scale micro-instabilities. This analysis method is designed to resolve the fluctuations in the emission line shape from a stationary ion-scale wave. The method linearizes the fluctuations around a time-averaged line shape (e.g., Gaussian) and subdivides the spectral output channels into two sets to reduce contributions from uncorrelated fluctuations without averaging over the fast time dynamics. In principle, small fluctuations in the parameters used for a line shape model can be measured by evaluating the cross spectrum between different channel groupings to isolate a particular fluctuating quantity. High-frequency ion velocity measurements (100-200 kHz) were made by using this method. We also conducted simulations to compare LSCA with a moment analysis technique under a low photon count condition. Both experimental and synthetic measurements demonstrate the effectiveness of LSCA.

  8. The atypical emission-line star Hen3-209

    NASA Astrophysics Data System (ADS)

    Nazé, Y.; Rauw, G.; Hutsemékers, D.; Gosset, E.; Manfroid, J.; Royer, P.

    2006-10-01

    We analyse observations, spanning 15 yr, dedicated to the extreme emission-line object Hen3-209. Our photometric data indicate that the luminosity of the star undergoes marked variations with a peak-to-peak amplitude of 0.65 mag. These variations are recurrent, with a period of 16.093 +/-0.005 d. The spectrum of Hen3-209 is peculiar with many different lines (HI, HeI, FeII, ...) showing P Cygni profiles. The line profiles are apparently changing in harmony with the photometry. The spectrum also contains [OIII] lines that display a saddle profile topped by three peaks, with a maximum separation of about 600 kms-1. Hen3-209 is most likely an evolved luminous object suffering from mass ejection events and maybe belonging to a binary system. Based on observations collected at the European Southern Observatory (La Silla, Chile) and the Cerro-Tololo Observatory (Chile). Postdoctoral Researcher FNRS (Belgium). ‡ E-mail: naze@astro.ulg.ac.be § Research Associate FNRS (Belgium). ¶ Research Director FNRS (Belgium).

  9. 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.

  10. Measuring Coronal Magnetic Fields with Coronal Emission Line Polarimetry

    NASA Astrophysics Data System (ADS)

    Lin, H.

    2003-12-01

    Magnetic field is the dominating field in the solar corona, responsible for the majestic coronal structures and dynamic events. However, no direct measurements of the coronal magnetic fields are routinely available and we can only infer the coronal magnetic field structures from observed intensity images. Although several methods for the diagnostics of coronal magnetic fields have been demonstrated, measurement of the coronal magnetic fields remains a very challenging observational task. This paper reports on a concerted effort at the Institute for Astronomy (IfA) to establish routine vector coronal magnetic field measurement capabilities using spectropolarimetric observation of the near infrared Fe XIII 1074.7 nm coronal emission line. The IfA effort includes observations of two-dimensional circular polarization maps of the emission line which carry information about the coronal magnetic field strength. High resolution observation of the linear polarization maps which yield the projected direction of the coronal magnetic field in the plane of the sky will also be obtained. The latest results from these experiments will be presented.

  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. Analysis and Interpretation of Astrophysical Optical Emission-Line Spectra

    NASA Astrophysics Data System (ADS)

    Loubser, S. I.

    This study consists of a quantitative optical emission-line analysis of spectra from five blue compact galaxies (Zw 0855, Mrk 1267, II Zw 33, Tol 2 & Tol 3), as well as a qualitative analysis of spectra from two galactic H II regions (NGC 3603 & NGC 3576). It serves a two-fold purpose: first, to understand the CCD reduction, spectra extraction and different nebular analysis methods, together with their applications and limitations, preparatory to studies using the Southern African Large Telescope (SALT) and second, to extend current star formation related research to include extragalactic starburst galaxies. The observations were carried out using the 1.9m telescope (equipped with a grating spectroscope and CCD detector) of the South African Astronomical Observatory (SAAO), during the period 1 to 7 March 2005. The necessary CCD data reduction, spectra extraction, wavelength and flux calibration, Doppler shift as well as reddening correction procedures were performed before the emission lines were identified and measured. A full nebular analysis, including temperature, density, metallicity (oxygen abundance) and other chemical abundance determinations, was performed on the blue compact galaxies (BCGs). Two different nebular analysis packages viz. IRAF's nebular and SNAP were used, with all the results well within the range of values expected for metal poor BCGs. Recommendations on the different methods and their applications are made.

  13. 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.

  14. Line Emission and X-ray Line Polarization of Multiply Ionized Mo Ions

    NASA Astrophysics Data System (ADS)

    Petkov, E. E.; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V.; Stafford, A.; Safronova, U. I.; Shrestha, I. K.; Schultz, K. A.; Childers, R.; Cooper, M. C.; Beiersdorfer, P.; Hell, N.; Brown, G. V.

    2016-10-01

    We present a comprehensive experimental and theoretical study of the line emission from multiply ionized Mo ions produced by two different sets of experiments: at LLNL EBIT and the pulsed power generator Zebra at UNR. Mo line emission and polarization measurements were accomplished at EBIT for the first time. In particular, benchmarking experiments at the LLNL EBIT with Mo ions produced at electron beam energies from 2.75 keV up to 15 keV allowed us to break down these very complicated spectra into spectra with only few ionization stages and to select processes that influence them as well as to measure line polarization. The EBIT data were recorded using the EBIT Calorimeter Spectrometer and a crystal spectrometer with a Ge crystal. X-ray Mo spectra and pinhole images were collected from Z-pinch plasmas produced from various wire loads. Non-LTE modeling, high-precision relativistic atomic and polarization data were used to analyze L-shell Mo spectra. The influence of different plasma processes including electron beams on Mo line radiation is summarized. This work was supported by NNSA under DOE Grant DE-NA0002954. Experiments at the NTF/UNR were funded in part by DE-NA0002075. Work at LLNL was performed under the auspices of the U.S. DOE under contract DE-AC52-07NA27344.

  15. 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.

  16. Bloated Stars as AGN Broad-line Clouds: The Emission Line Spectrum

    NASA Astrophysics Data System (ADS)

    Alexander, T.; Netzer, H.

    1994-10-01

    The Bloated Stars Scenario proposes that AGN broad line emission originates in the winds or envelopes of bloated stars (BS). Its main advantage over BLR cloud models is the gravitational confinement of the gas and its major difficulty the large estimated number of BSs and the resulting high collisional and evolutionary mass loss rates. Previous work on this model did not include full calculations of the spectrum and used very simplified stellar distribution functions. Here we calculate the emission line spectrum by applying a detailed numerical photoionization code to the wind and by assuming a detailed nucleus model (Murphy,Cohn & Durisen 1991). We study a wide range of wind structures for a QSO model with Lion = 7E45 erg/s, Mbh = 8E7 Mo and a stellar core density of 7E7 Mo pc^3. The BSs emit a spherically symmetric wind whose size and boundary density are determined by various processes: Comptonization by the central continuum source, calculated here self consistently, tidal disruption by the black hole and the limit set by the wind's finite mass. We find that the emission spectrum is mainly determined by the conditions at the boundary of the line emitting fraction of the wind rather than by its internal structure. Comptonization results in a very high ionization parameter at the boundary which produces an excess of unobserved broad high excitation forbidden lines. The finite mass constraint limits the wind size, increases the boundary density and thus improves the results. Slow, decelerating, mass-constrained flows with high gas densities (10E8 to 10E12 cm^-3) are as successful as cloud models in reproducing the overall observed line spectrum. The MgII2798 and NV1240 lines are however under-produced in our models. We adjust the number of BSs so as to obtain the observed EW(Lya) and find that only ~ 5E4 BSs with dense winds are required in the inner 1/3 pc. This small fraction approaches that of supergiants (SG) in the solar neighborhood and the calculated mass

  17. 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.

  18. Hα Monitoring of Early-Type Emission Line Stars

    NASA Astrophysics Data System (ADS)

    Souza, Steven P.; Boettcher, E.; Wilson, S.; Hosek, M.

    2011-05-01

    We have begun a narrowband imaging program to monitor Hα emission in early-type stars in young open clusters and associations. A minority of early-type stars, particularly Be stars, show Hα in emission due to extended atmospheres and non-equilibrium conditions. Emission features commonly vary irregularly over a range of timescales (Porter, J.M. & Rivinus, T., P.A.S.P. 115:1153-1170, 2003). Some of the brightest such stars, e.g. γ Cas, have been spectroscopically monitored for Hα variability to help constrain models of the unstable disk, but there is relatively little ongoing monitoring in samples including fainter stars (Peters, G., Be Star Newsletter 39:3, 2009). Our program uses matched 5nm-wide on-band (656nm) and off-band (645nm) filters, in conjunction with the Hopkins Observatory 0.6-m telescope and CCD camera. Aperture photometry is done on all early-type stars in each frame, and results expressed as on-band to off-band ratios. Though wavelength-dependent information is lost compared with spectroscopy, imaging allows us to observe much fainter (and therefore many more) objects. Observing young clusters, rather than individual target stars, allows us to record multiple known and candidate emission line stars per frame, and provides multiple "normal" reference stars of similar spectral type. Observations began in the summer of 2010. This project has the potential to produce significant amounts of raw data, so a semi-automated data reduction process has been developed, including astrometric and photometric tasks. Early results, including some preliminary light curves and recovery of known Be stars at least as faint as R=13.9, are presented. We gratefully acknowledge support for student research through an REU grant to the Keck Northeast Astronomy Consortium from the National Science Foundation, and from the Division III Research Funding Committee of Williams College.

  19. 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.

  20. The Local Bubble's O VI Resonance Line Emission Challenges Expectations

    NASA Astrophysics Data System (ADS)

    Shelton, R. L.

    2002-12-01

    Based on its 1/4 keV X-ray emission, the Local Bubble surrounding the solar neighborhood is thought to be a large ( ~70 pc) bubble of very highly ionized gas. Whether it is a 106 K bubble wrapped in a cooler (few times 105 K) transition zone or a tepid, overionized bubble, the Local Bubble is thought to contain a large column density of O VI ions and to radiate strongly in the O VI resonance lines. However, our observations place very tight upper limits on its O VI resonance line intensity (2 sigma values of 420 and 540 photons/s/cm2/sr in the 1032 and 1038 Angstrom lines, respectively). The resulting upper limit on the doublet intensity is far less than that expected from the most current models of the Local Bubble. The disagreement raises fundamental questions about the physics of transition zones in the first type of model and raises concerns about the ionization state in the second type of model.

  1. Are Black Hole Masses from broad emission lines reliable

    NASA Astrophysics Data System (ADS)

    Mejia-Restrepo, Julian; Trakhtenbrot, B.; Lira, P.; Netzert, H.; Capellupo, D.

    2015-09-01

    For a proper understanding of AGNs we requires accurate estimates of the central Black Hole Mass (MBH). Here we discuss the comparison of single-epoch (SE) MBH estimators based on low ionization (Hα, Hβ, and MgII) and high ionization (CIV) broad emission lines. We use a sample of 39 unobscured AGNs at z=1.55 selected to cover a large range in MBH (2.0dex) and L/Ledd (2.5dex) and observed by X-shooter. We corroborate that low ionization lines can generally be safely used for virial MBH estimations. We found that the FWHM(MgII) is in general about 30% narrower than the FWHM of Hβ and Hα. However, high accretion rate objects show FWHM(MgII) similar or even broader than FWHM(Hβ) indicating that MgII is not suitable for MBH estimation in these objects. We confirm the systematic uncertainties associated with the use of the high ionization CIV line basically because its dynamics is highly affected by the accretion rate that induces radiation-driven winds.

  2. 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 good...

  3. 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 good...

  4. 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 good...

  5. 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 good...

  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, 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 good...

  7. Far-infrared line emission from high-redshift galaxies

    NASA Astrophysics Data System (ADS)

    Vallini, Livia; Gallerani, Simona; Ferrara, Andrea; Baek, Sunghye

    2013-08-01

    By combining high-resolution, radiative transfer cosmological simulations of z ≈ 6 galaxies with a subgrid multiphase model of their interstellar medium, we derive the expected intensity of several far-infrared emission lines ([C II] 158, [O I] 63 and [N II] 122 μm) for different values of the gas metallicity, Z. For Z = Z⊙, the [C II] spectrum is very complex due to the presence of several emitting clumps of individual sizes ≲3 kpc; the peak is displaced from the galaxy centre by ≈100 km s-1. While the [O I] spectrum is also similarly displaced, the [N II] line comes predominantly from the central ionized regions of the galaxy. When integrated over ˜ 500 km s- 1, the [C II] line flux is 185 mJy km s- 1; 95 per cent of such flux originates from the cold (T ≈ 250 K) H I phase and only 5 per cent from the warm (T ≈ 5000 K) neutral medium. The [O I] and [N II] fluxes are ˜6 and ˜90 times lower than the [C II] one, respectively. By comparing our results with observations of Himiko, the most extended and luminous Lyman alpha emitter at z = 6.6, we find that the gas metallicity in this source must be subsolar. We conclude that the [C II] line from z ≈ 6 galaxies is detectable by the ALMA full array in 1.9 < tON < 7.7 h observing time, depending on Z.

  8. Emergence of double-peaked emission lines in the broad-line radio galaxy Pictor A

    NASA Astrophysics Data System (ADS)

    Halpern, Jules P.; Eracleous, Michael

    1994-09-01

    A new optical spectrum of the nearby broad-line radio galaxy (BLRG) Pictor A reveals a prominent double-peaked component of the Balmer lines which does not appear in any historical spectra of this object. Carried out with the hope of obtaining exactly such a result, this observation is a key to the interpretation of double-peaked emitters. If bolsters our previous conclusion that there is a set of additional properties which are associated with the rare class of double-peaked emitters, namely F-R II radio morphology, strong low-ionization forbidden lines, weak UV continuum, and flat far-infrared spectrum. Furthermore, the low-velocity, 'ordinary' broad Balmer lines in Pictor A remained relatively unchanged as the new twin peaks appeared, which justifies the practice of applying models that fit only the double peaks and not the low-velocity components that are often present in spectra of this type. We discuss the relative merits of accretion-disk models and other models for double-peaked emission lines in the light of this new observation.

  9. Emergence of double-peaked emission lines in the broad-line radio galaxy Pictor A

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.; Eracleous, Michael

    1994-01-01

    A new optical spectrum of the nearby broad-line radio galaxy (BLRG) Pictor A reveals a prominent double-peaked component of the Balmer lines which does not appear in any historical spectra of this object. Carried out with the hope of obtaining exactly such a result, this observation is a key to the interpretation of double-peaked emitters. If bolsters our previous conclusion that there is a set of additional properties which are associated with the rare class of double-peaked emitters, namely F-R II radio morphology, strong low-ionization forbidden lines, weak UV continuum, and flat far-infrared spectrum. Furthermore, the low-velocity, 'ordinary' broad Balmer lines in Pictor A remained relatively unchanged as the new twin peaks appeared, which justifies the practice of applying models that fit only the double peaks and not the low-velocity components that are often present in spectra of this type. We discuss the relative merits of accretion-disk models and other models for double-peaked emission lines in the light of this new observation.

  10. Extent and structure of intervening absorbers from absorption lines redshifted on quasar emission lines

    NASA Astrophysics Data System (ADS)

    Bergeron, J.; Boissé, P.

    2017-07-01

    Aims: We wish to study the extent and sub-parsec spatial structure of intervening quasar absorbers, mainly those involving cold neutral and molecular gas. Methods: We have selected quasar absorption systems with high spectral resolution and a good signal-to-noise ratio data, with some of their lines falling on quasar emission features. By investigating the consistency of absorption profiles seen for lines formed either against the quasar continuum source or on the much more extended (Lyα-N v, C iv or Lyβ-O vi) emission line region (ELR), we can probe the extent and structure of the foreground absorber over the extent of the ELR ( 0.3-1 pc). The spatial covering analysis provides constraints on the transverse size of the absorber and thus is complementary to variability or photoionisation modelling studies, which yield information on the absorber size along the line of sight. The methods we used to identify spatial covering or structure effects involve line profile fitting and curve-of-growth analysis. Results: We have detected three absorbers with unambiguous non-uniformity effects in neutral gas. For the extreme case of the Fe I absorber at zabs = 0.45206 towards HE 0001-2340, we derive a coverage factor of the ELR of at most 0.10 and possibly very close to zero; this implies an overall absorber size no larger than 0.06 pc. For the zabs = 2.41837 C I absorber towards QSO J1439+1117, absorption is significantly stronger towards the ELR than towards the continuum source in several C I and C I⋆ velocity components, pointing to spatial variations of their column densities of about a factor of two and to structures at the 100 au-0.1 pc scale. The other systems with firm or possible effects can be described in terms of a partial covering of the ELR, with coverage factors in the range 0.7-1. The overall results for cold neutral absorbers imply a transverse extent of about five times the ELR size or smaller, which is consistent with other known constraints. Although

  11. A versatile apparatus for on-line emission channeling experiments

    SciTech Connect

    Silva, M. R.; Wahl, U.; Correia, J. G.

    2013-07-15

    The concept and functionality of an apparatus dedicated to emission channeling experiments using short-lived isotopes on-line at ISOLDE/CERN is described. The setup is assembled in two functional blocks – (a) base stand including beam collimation, implantation and measurement chamber, cryogenic extension, and vacuum control system and (b) Panmure goniometer extension including maneuvering cradle and sample heating furnace. This setup allows for in situ implantation and sample analysis in the as-implanted state and upon cooling down to 50 K and during annealing up to 1200 K. The functionality of the setup will be illustrated with the example of establishing the lattice location of {sup 56}Mn probes implanted into GaAs.

  12. A versatile apparatus for on-line emission channeling experiments.

    PubMed

    Silva, M R; Wahl, U; Correia, J G; Amorim, L M; Pereira, L M C

    2013-07-01

    The concept and functionality of an apparatus dedicated to emission channeling experiments using short-lived isotopes on-line at ISOLDE∕CERN is described. The setup is assembled in two functional blocks - (a) base stand including beam collimation, implantation and measurement chamber, cryogenic extension, and vacuum control system and (b) Panmure goniometer extension including maneuvering cradle and sample heating furnace. This setup allows for in situ implantation and sample analysis in the as-implanted state and upon cooling down to 50 K and during annealing up to 1200 K. The functionality of the setup will be illustrated with the example of establishing the lattice location of (56)Mn probes implanted into GaAs.

  13. Searching for emission-line galaxies: The UCM survey

    NASA Technical Reports Server (NTRS)

    Gallego, J.; Zamorano, J.; Rego, M.; Vitores, A.

    1993-01-01

    We are carrying out a long-term project with the main purposes of finding and analyzing low metallicity galaxies. A very small number of very low metallicity galaxies is known up to now. However these ojbects are particularly interesting since they are excellent candidates to 'young galaxies' in evolutionary sense as POX186 (Kunth, Maurogordato & Vigroux, 1988). Since the interstellar matter in these objects is only weakly contaminated by stellar evolution, their study could provide valuable information about the primordial helium abundance and therefore it could place constraints on the different Big-Bang models. The instrumental set up of our survey is an objective-prism used with the Schmidt telescope at Calar Alto Observatory. By using hypersensitized IIIaF emulsion and RG630 filter low resolution spectra in the H alpha region of objects in a wide field is obtained (Rego et al. 1989, Zamorano et al. 1990). Surveys carried out in the past two decades at optical blue wavelengths have also produced large samples of emission-line galaxies (ELGs), for example MacAlpine & Willians 1981 and reference therein, Wasilewski 1983, Salzer and MacAlpine 1988, or Smith et al. 1976. Relying primarily on objective-prism plates taken in the blue, these surveys have found over 3000 blue/emission-line galaxies so far. A significant number of star-forming galaxies are missed by optical surveys in the blue because of their low-excitation spectra (MacAlpine and Willians 1981, Markarian et al. 1981 and references therein) or their low metallicity (Kunth and Sargent, 1986).

  14. Molecular line emission in NGC 1068 imaged with ALMA

    NASA Astrophysics Data System (ADS)

    Garcia-Burillo, S.

    2015-09-01

    We investigate the fueling and the feedback of star formation and nuclear activity in NGC1068, a nearby Seyfert 2 barred galaxy, by analyzing the distribution and kinematics of the molecular gas in the disk. We have used ALMA to map the emission of a set of dense molecular gas tracers and their underlying continuum emission in the central r=2 kpc of NGC1068 with spatial resolutions 0.3"-0.5" (20-35 pc). Molecular line and dust continuum emissions are detected from a r=200 pc off-centered circumnuclear disk (CND), from the 2.6 kpc-diameter bar region, and from the r=1.3 kpc starburst (SB) ring. We used the dust continuum fluxes measured by ALMA together with NIR/MIR data to constrain the properties of the putative torus using CLUMPY models and found a torus radius of 20(6,-10)pc. The gas kinematics from r=50 pc out to r=400 pc reveal a massive outflow in all molecular tracers. The tight correlation between the ionized gas outflow, the radio jet and the occurrence of outward motions in the disk suggests that the outflow is AGN-driven. The outflow rate estimated in the CND, dM/dt=63(21,-37)M(sun)/yr, is an order of magnitude higher than the star formation rate at these radii, confirming that the outflow is AGN-driven. The power of the AGN is able to account for the estimated momentum and kinetic luminosity of the outflow. The CND mass load rate of the CND outflow implies a very short gas depletion time scale of 1 Myr.

  15. Molecular line emission models of Herbig-Haro objects. I - H2 emission

    NASA Technical Reports Server (NTRS)

    Wolfire, Mark G.; Konigl, Arieh

    1991-01-01

    A comprehensive model for molecular hydrogen emssion in Herbig-Haro objects that are associated with the heads of radiative stellar jets is presented by using a simple representation of the jet head as a comprising a leading bow shock and a trailing jet shock, separated by a dense layer of cool shocked gas. Attention is given to collisional excitation in a nondissociative shock and formation pumping in the molecular reformation zone behind a dissociative shock, employing detailed shock and photodissociation-region emission models that incorporate most of the relevant atomic physics and chemistry. The conditions under which each of these excitation mechanisms may be expected to contribute to the observed emission are discussed, and a general diagnostic scheme for discriminating among them is constructed. Applying this scheme to the HH 1-2 system, strong evidence for excitation by the radiation field of a fast shock is found. It is inferred that FUV pumping contributes a significant fraction of the H2 line emission, and it is shown that this can occur only if the UV pump lines are not strongly self-shielded.

  16. Line Emission in Active Galactic Nuclei: Effects of Local Delays upon Line Variability

    NASA Astrophysics Data System (ADS)

    Taylor, Jason A.

    1996-10-01

    Previous works concerning active galactic nuclei (AGNs) variability (e.g., Blandford & McKee 1982) have assumed that the emission characteristics of illuminated clouds are purely a function of the instant continuum flux to which they are exposed. This paper shows that this assumption is not necessarily justified and that the history of exposure accounting for "local delays" due to finite cloud equilibrium times can also be relevant. For this reason, a new formalism is developed in this paper for computing the observational properties of models that have local delays. The nature of the nonlinear behavior that results is calculated for some very simple nonlinear cloud line emission models. It is found that the mean response time is a function of the recent average value of the continuum. Linear models fitted to these nonlinear systems respond too slowly when there are low-energy (and generally rapid) changes in the continuum, yet respond too rapidly when there are high- energy (and generally slow) changes in the continuum. As with systems without local delays, the expression for the time-dependent line flux contains an integration over history of the "spatial" response function, which has structure at lags of the light travel times of the emission region. However, the kernel of this integral itself is a function of additional integrations over individual "cloud" response functions that have structure at lags of the equilibrium times of the cloud properties relevant to line emission. In the linear regime, the response can be approximated using a single response function. The integral of this function over lag is not generally equal to the mean flux in the line. Rather, it differs by a factor that is the strength of response for low- frequency continuum excitations or simply the "asymptotic gain," which is unity only in fully linear models. If instantaneous or linear response is incorrectly assumed, local delays and nonlinear response can make a system appear larger

  17. Hydrogen line and continuum emission in young stellar objects. III - Line ratios and physical conditions

    NASA Technical Reports Server (NTRS)

    Alonso-Costa, Jose L.; Kwan, John

    1990-01-01

    A detailed analysis of the dependence of Br-gamma/Br-alpha and other hydrogen line ratios on nucleon density (over the range 10 to the 10th - 10 to the 12th/cu cm), column density (about 10 to the 18th - 10 to the 24th/sq cm), young stellar object (YSO) luminosity (about 10-10,000 solar luminosities), and distance of the gas cloud from the YSO, r (about 10 to the 12th - 10 to the 14th cm). For a given continuum model, the value of Br-gamma/Br-alpha can provide a constraint on r. The ionization and thermal structures of the emission region are described. The electron fraction is fairly constant and is small (less than 10 percent) in the region where most of the hydrogen line fluxes are produced. The temperature in this region is also quite constant, with a value of 5000-7000 K.

  18. HST Emission Line Galaxies at z ~ 2: Comparing Physical Properties of Lyman Alpha and Optical Emission Line Selected Galaxies

    NASA Astrophysics Data System (ADS)

    Hagen, Alex; Zeimann, Gregory R.; Behrens, Christoph; Ciardullo, Robin; Grasshorn Gebhardt, Henry S.; Gronwall, Caryl; Bridge, Joanna S.; Fox, Derek B.; Schneider, Donald P.; Trump, Jonathan R.; Blanc, Guillermo A.; Chiang, Yi-Kuan; Chonis, Taylor S.; Finkelstein, Steven L.; Hill, Gary J.; Jogee, Shardha; Gawiser, Eric

    2016-01-01

    We compare the physical and morphological properties of z ˜ 2 Lyα emitting galaxies (LAEs) identified in the HETDEX Pilot Survey and narrow band studies with those of z ˜ 2 optical emission line selected galaxies (oELGs) identified via HST WFC3 infrared grism spectroscopy. Both sets of galaxies extend over the same range in stellar mass (7.5\\lt {log}M/{M}⊙ \\lt 10.5), size (0.5 < R < 3.0 kpc), and star formation rate (˜ 1\\lt {{SFR}}\\lt 100 {M}⊙ yr-1). Remarkably, a comparison of the most commonly used physical and morphological parameters—stellar mass, half-light radius, UV slope, SFR, ellipticity, nearest neighbor distance, star formation surface density, specific SFR, [O iii] luminosity, and [O iii] equivalent width—reveals no statistically significant differences between the populations. This suggests that the processes and conditions which regulate the escape of Lyα from a z ˜ 2 star-forming galaxy do not depend on these quantities. In particular, the lack of dependence on the UV slope suggests that Lyα emission is not being significantly modulated by diffuse dust in the interstellar medium. We develop a simple model of Lyα emission that connects LAEs to all high-redshift star-forming galaxies where the escape of Lyα depends on the sightline through the galaxy. Using this model, we find that mean solid angle for Lyα escape is {{{Ω }}}{{Ly}α }=2.4+/- 0.8 steradians; this value is consistent with those calculated from other studies.

  19. The impossibility of recording emission lines of nitrogen ions in filament plasma

    NASA Astrophysics Data System (ADS)

    Ilyin, A. A.

    2016-10-01

    It is shown that the emission lines of N II nitrogen ions cannot contribute to the emission of other lines and be observed in the emission spectrum of plasma filaments, which are generated by femtosecond laser pulses with a peak intensity of 50 TW/cm2 in air. A simple procedure is described that allows evaluation of the ratio of the line intensities for the filamentation in air.

  20. A catalog of early-type emission-line stars and Hα line profiles from LAMOST DR2

    NASA Astrophysics Data System (ADS)

    Hou, Wen; Luo, A.-Li; Hu, Jing-Yao; Yang, Hai-Feng; Du, Chang-De; Liu, Chao; Lee, Chien-De; Lin, Chien-Cheng; Wang, Yue-Fei; Zhang, Yong; Cao, Zi-Huang; Hou, Yong-Hui

    2016-09-01

    We present a catalog including 11 204 spectra of 10 436 early-type emission-line stars from LAMOST DR2, among which 9752 early-type emission-line spectra are newly discovered. For these early-type emission-line stars, we discuss the morphological and physical properties of their low-resolution spectra. In this spectral sample, the Hα emission profiles display a wide variety of shapes. Based on the Hα line profiles, these spectra are categorized into five distinct classes: single-peak emission, single-peak emission in absorption, double-peak emission, double-peak emission in absorption, and P-Cygni profiles. To better understand what causes the Hα line profiles, we divide these objects into four types from the perspective of physical classification, which include classical Be stars, Herbig Ae/Be stars, close binaries and spectra contaminated by HΠ regions. The majority of Herbig Ae/Be stars and classical Be stars are identified and separated using a (H-K, K-W1) color-color diagram. We also discuss 31 binary systems that are listed in the SIMBAD on-line catalog and identify 3600 spectra contaminated by HΠ regions after cross-matching with positions in the Dubout-Crillon catalog. A statistical analysis of line profiles versus classifications is then conducted in order to understand the distribution of Hα profiles for each type in our sample. Finally, we also provide a table of 172 spectra with Fe Π emission lines and roughly calculate stellar wind velocities for seven spectra with P-Cygni profiles.

  1. The Herbig AE star AB AUR - absorption along the line of sight and chromospheric emission

    NASA Astrophysics Data System (ADS)

    Felenbok, P.; Praderie, F.; Talavera, A.

    1983-11-01

    The H-alpha, He I 5876 A, Na I 5890 A, Ca II IR triplet, and P14-P16 Paschen lines of AB Aur are all brighter than the nearby continuum. The emission lines are examined with regard to their origin as either recombination or chromospheric emission. While He I and H-alpha could be formed simultaneously by recombination under certain circumstances, a deep chromosphere would account for He I 5876, for the Paschen lines in emission, and perhaps even for the Ca II IR triplet in emission. A deep chromosphere would also explain why higher Balmer lines are in absorption and why the Ca II resonance lines have only an autoreversed emission core, despite not being fully in emission.

  2. On the sodium D line emission in the terrestrial nightglow

    NASA Astrophysics Data System (ADS)

    Plane, John; Oetjen, Hilke; de Miranda, Marcelo; Saiz-Lopez, Alfonso; Gausa, Michael; Williams, Bifford

    2012-01-01

    Emission from atomic Na, consisting of a doublet of lines at 589.0 and 589.6 nm, is a prominent feature of the earth’s nightglow. A large data-base of measurements of the relative intensities of the D lines (RD) was gathered at three locations: the ALOMAR observatory, Andenes (Norway, 69°N), Kuujjuarapik (Canada, 55°N) and the Danum Valley (Borneo, 8°N). RD varies between 1.5 and 2.0, with an average value of 1.67. These results were interpreted using a theoretical model of the Na nightglow which involves initial production of electronically excited NaO(A2Σ) from the reaction between Na and O3, followed either by reaction with O to generate Na(2PJ) with a branching ratio of 1/6 and a J=3/2 to 1/2 propensity of 2.0, or quenching of NaO(A) to NaO(X2Π) by O2. The resulting NaO(X) then reacts with O to generate Na(2PJ) with a branching ratio of 1/6 and a J=3/2 to 1/2 propensity of 1.5. These branching ratios and spin-orbit propensities are derived from statistical correlation of the electronic potential energy surfaces connecting the reactants NaO(A)+O and NaO(X)+O with the products Na+O2, through the Na+O2- ion-pair intermediate. A fit of this statistical model to the results of an earlier laboratory study (Slanger et al., 2005), where RD was measured as a function of the ratio [O]/[O2], indicates that the rate coefficient for the quenching of NaO(A) by O2 is around 1×10-11 cm3 molecule-1 s-1. The statistical model is also in good accord with recent high resolution observations of the Na D line widths (Harrell et al., 2010). An atmospheric model is then used to show that gravity wave-driven perturbations to the Na layer can account for the observed variability of RD.

  3. Coronal Physics and the Chandra Emission Line Project

    NASA Technical Reports Server (NTRS)

    Brickhouse, N. S.; Drake, J. J.

    2000-01-01

    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 Capella, Procyon, and HR 1099 are providing not only invaluable calibration data, but also benchmarks for plasma spectral models. These models are needed to interpret data from stellar coronae, galaxies and clusters of galaxies, supernova, remnants and other astrophysical sources. They have been called into question in recent years as problems with understanding low resolution ASCA and moderate resolution Extreme Ultraviolet Explorer Satellite (EUVE) data have arisen. The Emission Line Project is a collaborative effort, to improve the models, with Phase I 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, negligible optical depth) apply. We will discuss recent, advances in our understanding of stellar coronae, in this context.

  4. 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.

  5. DETECTION OF REST-FRAME OPTICAL LINES FROM X-SHOOTER SPECTROSCOPY OF WEAK EMISSION-LINE QUASARS

    SciTech Connect

    Plotkin, Richard M.; Gallo, Elena; Shemmer, Ohad; Trakhtenbrot, Benny; Anderson, Scott F.; Brandt, W. N.; Luo, Bin; Schneider, Donald P.; Fan, Xiaohui; Lira, Paulina; Richards, Gordon T.; Strauss, Michael A.; Wu, Jianfeng

    2015-06-01

    Over the past 15 yr, examples of exotic radio-quiet quasars with intrinsically weak or absent broad emission line regions (BELRs) have emerged from large-scale spectroscopic sky surveys. Here, we present spectroscopy of seven such weak emission line quasars (WLQs) at moderate redshifts (z = 1.4–1.7) using the X-shooter spectrograph, which provides simultaneous optical and near-infrared spectroscopy covering the rest-frame ultraviolet (UV) through optical. These new observations effectively double the number of WLQs with spectroscopy in the optical rest-frame, and they allow us to compare the strengths of (weak) high-ionization emission lines (e.g., C iv) to low-ionization lines (e.g., Mg ii, Hβ, Hα) in individual objects. We detect broad Hβ and Hα emission in all objects, and these lines are generally toward the weaker end of the distribution expected for typical quasars (e.g., Hβ has rest-frame equivalent widths ranging from 15–40 Å). However, these low-ionization lines are not exceptionally weak, as is the case for high-ionization lines in WLQs. The X-shooter spectra also display relatively strong optical Fe ii emission, Hβ FWHM ≲ 4000 km s{sup −1}, and significant C iv blueshifts (≈1000–5500 km s{sup −1}) relative to the systemic redshift; two spectra also show elevated UV Fe ii emission, and an outflowing component to their (weak) Mg ii emission lines. These properties suggest that WLQs are exotic versions of “wind-dominated” quasars. Their BELRs either have unusual high-ionization components, or their BELRs are in an atypical photoionization state because of an unusually soft continuum.

  6. On the 630 nm red-line pulsating aurora: Red-line Emission Geospace Observatory observations and model simulations

    NASA Astrophysics Data System (ADS)

    Liang, Jun; Donovan, E.; Jackel, B.; Spanswick, E.; Gillies, M.

    2016-08-01

    In this study, we present observations of red-line (630 nm) pulsating auroras using the camera system of Red-line Emission Geospace Observatory (REGO), during a geomagnetic storm interval. We also develop a time-dependent model to simulate the 630 nm auroral pulsations in response to modulated precipitation inputs and compare the model outputs with REGO observations. Key results are as follows. (1) Notwithstanding the long radiative timescale of the 630 nm emission, red-line auroras can still be modulated by pulsating electron precipitations and feature noticeable oscillations, which constitute the red-line pulsating auroral phenomena. (2) In a majority of cases, the oscillation magnitude of red-line pulsating auroras is substantially smaller than that of the concurrent pulsating auroras seen on Thermal Emission Imaging System whitelight images (generally dominated by 557.7 nm green-line emissions). Under certain circumstances, e.g., when the characteristic energy of the precipitation is very high, some of the pulsating auroras may not show discernible imprints on red line. (3) The altitude range contributing most to the red-line pulsating aurora is systematically lower than that of the steady-state red-line aurora, since the slower O(1D) loss rate at higher altitudes tends to suppress the oscillation range of the 630 nm emission rate. (4) We find that some pulsating auroral patches are characterized by enhanced red-to-green color ratio during their on time, hinting that the percentage increase of the red-line auroral component exceeds that of the green-line auroral component for those patches. We suggest that those special patches might possibly be associated with lower energy (<1 keV) electron precipitations.

  7. VizieR Online Data Catalog: Emission lines from giant HII regions (Garcia Vargas+, 1995)

    NASA Astrophysics Data System (ADS)

    Garcia Vargas, M. L.; Bressan, A.; Diaz, A. I.

    1995-03-01

    We have computed theoretical models of the emission line spectra of giant extragalactic HII regions (GEHR) in which a single star cluster is assumed to be responsible for the ionization. In this paper we present the synthetic emission line spectra of the ionized regions. (1 data file).

  8. Principal Component Analysis of Computed Emission Lines from Protostellar Jets

    NASA Astrophysics Data System (ADS)

    Cerqueira, A. H.; Reyes-Iturbide, J.; De Colle, F.; Vasconcelos, M. J.

    2015-08-01

    A very important issue concerning protostellar jets is the mechanism behind their formation. Obtaining information on the region at the base of a jet can shed light on the subject, and some years ago this was done through a search for a rotational signature in the jet line spectrum. The existence of such signatures, however, remains controversial. In order to contribute to the clarification of this issue, in this paper we show that principal component analysis (PCA) can potentially help to distinguish between rotation and precession effects in protostellar jet images. This method reduces the dimensions of the data, facilitating the efficient extraction of information from large data sets such as those arising from integral field spectroscopy. PCA transforms the system of correlated coordinates into a system of uncorrelated coordinates, the eigenvectors, ordered by principal components of decreasing variance. The projection of the data on these coordinates produces images called tomograms, while eigenvectors can be displayed as eigenspectra. The combined analysis of both can allow the identification of patterns correlated to a particular physical property that would otherwise remain hidden, and can help to separate the effects of physically uncorrelated phenomena in the data. These are, for example, rotation and precession in the kinematics of a stellar jet. In order to show the potential of PCA analysis, we apply it to synthetic spectro-imaging datacubes generated as an output of numerical simulations of protostellar jets. In this way we generate a benchmark with which a PCA diagnostics of real observations can be confronted. Using the computed emission line profiles for [O i]λ6300 and [S ii]λ6716, we recover and analyze the effects of rotation and precession in tomograms generated by PCA. We show that different combinations of the eigenvectors can be used to enhance and to identify the rotation features present in the data. Our results indicate that PCA can be

  9. 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

  10. 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.

  11. VizieR Online Data Catalog: MUSE-Wide survey: 831 emission line galaxies (Herenz+, 2017)

    NASA Astrophysics Data System (ADS)

    Herenz, E. C.; Urrutia, T.; Wisotzki, L.; Kerutt, J.; Saust, R.; Werhahn, M.; Schmidt, K. B.; Caruana, J.; Diener, C.; Bacon, R.; Brinchman, J.; Schaye, J.; Maseda, M.; Weilbacher, P. M.

    2017-05-01

    This data release consists of an emission line galaxy catalogue containing 831 emission line galaxies detected in the first period of observations of the MUSE-Wide survey. We also release 1D PSF-weighted extracted spectra and 3D datacubes for each of those 831 sources. The emission line galaxy catalogue consists of two tables: A catalogue of all 831 detected emission line objects and a table of all 1652 detected emission lines in those objects. These tables are described in detail in Sect. 4.1 and 4.2 of the paper. Both tables are in the FITS binary table format, adhering to the FITS standard described in Pence et al. (2010A&A...524A..42P). (8 data files).

  12. Spectrophotometry of H-Alpha Emission-Line Stars in the LMC

    NASA Astrophysics Data System (ADS)

    Bohannan, Bruce

    As part of a study of the bright emission-line stars in the Large Magellanic Cloud, ultraviolet spectrophotometry from IUE will be combined with narrow-band visible photometry to measure effective temperatures and gravities of the most pathological stars in the sample through comparison of observed fluxes with Kurucz model atmospheres. IUE spectrophotometry is required because the spectra of early-type emission-line stars are often so complex that visible light absorption-line strengths can be a potentially misleading indicator of effective temperature. Indeed, some of these stars have such strong emission-lines from their dense, extended atmospheres that they have no lines arising from the photosphere. The overall goal of this research is to locate the sample of LMC emission-line stars in the Hertzsprung-Russell diagram to gain an understanding of the paths that massive stars take in evolving from main sequence 0-type stars to Wolf-Rayet stars.

  13. Diffuse far-infrared [C II] line emission from high Galactic latitude

    NASA Astrophysics Data System (ADS)

    Makiuti, S.; Shibai, H.; Nakagawa, T.; Okuda, H.; Okumura, K.; Matsuhara, H.; Hiromoto, N.; Doi, Y.

    2002-02-01

    The Far-Infrared Line Mapper (FILM) onboard the Infrared Telescope in Space (IRTS) made a survey for the far-infrared [C Ii] 158 mu m line emission with high sensitivity and moderate spatial resolution. We have found that diffuse [C Ii] line emission extends to high Galactic latitude regions. The [C Ii] line intensity at | b | ~ 60deg ranges from 2*E-7 to 1.5*E-6 erg cm-2 s-1 sr-1. Comparisons of the distribution of the [C Ii] line emission with those of the H I column density and far-infrared radiation show some correlations, but the [C Ii] line emission differs from the far-IR and HI emission at high Galactic latitudes. These differences suggest that the [C Ii] line primarily comes from ionized gas in the high-latitude regions. The intensities of the [C Ii] line emission on the southern side (b < 0deg) of the Galactic plane are systematically larger than those on the northern side (b > 0deg). We infer from this difference that there is a displacement of the Sun with respect to the center of interstellar medium from which the [C Ii] line comes. When an exponential distribution is assumed for the [C Ii] emitting gas, it is expected that the Sun is located at the distance of about 17% of the scale height above the center of the gas. This is consistent with the previously reported displacement of the Sun from the Galactic plane.

  14. KILOPARSEC-SCALE PROPERTIES OF EMISSION-LINE GALAXIES

    SciTech Connect

    Hemmati, Shoubaneh; Miller, Sarah H.; Mobasher, Bahram; Nayyeri, Hooshang; Ferguson, Henry C.; Koekemoer, Anton M.; Guo, Yicheng; Koo, David C.

    2014-12-20

    We perform a detailed study of the resolved properties of emission-line galaxies at kiloparsec scales to investigate how small-scale and global properties of galaxies are related. We use a sample of 119 galaxies in the GOODS fields. The galaxies are selected to cover a wide range in morphologies over the redshift range 0.2 < z < 1.3. High resolution spectroscopic data from Keck/DEIMOS observations are used to fix the redshift of all the galaxies in our sample. Using the HST/ACS and HST/WFC3 imaging data taken as a part of the CANDELS project, for each galaxy, we perform spectral energy distribution fitting per resolution element, producing resolved rest-frame U – V color, stellar mass, star formation rate (SFR), age, and extinction maps. We develop a technique to identify ''regions'' of statistical significance within individual galaxies, using their rest-frame color maps to select red and blue regions, a broader definition for what are called ''clumps'' in other works. 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 of ∼0.6 dex. The blue regions show higher specific SFRs (sSFRs) than their red counterparts with the sSFR decreasing since z ∼ 1, driven primarily by the stellar mass surface densities rather than the SFRs at a given resolution element.

  15. Atomic emission lines in the near ultraviolet; hydrogen through krypton, section 1

    NASA Technical Reports Server (NTRS)

    Kelly, R. L.

    1979-01-01

    A compilation of spectra from the first 36 elements was prepared from published literature available through October 1977. In most cases, only those lines which were actually observed in emission or absorption are listed. The wavelengths included range from 2000 Angstroms to 3200 Angstroms with some additional lines up to 3500 Angstroms. Only lines of stripped atoms are reported; no molecular bands are included.

  16. Atomic emission lines in the near ultraviolet; hydrogen through krypton, section 2

    NASA Technical Reports Server (NTRS)

    Kelly, R. L.

    1979-01-01

    A compilation of spectra from the first 36 elements was prepared from published literature available through October 1977. In most cases, only those lines which were actually observed in emission or absorption are listed. The wavelengths included range from 2000 Angstroms to 3200 Angstroms with some additional lines up to 3500 Angstroms. Only lines of stripped atoms are reported; no molecular bands are included.

  17. Linings with optimum heat-emission surfaces for cars receiving and transporting incandescent coke

    SciTech Connect

    Kotlyar, B.D.; Pleshkov, P.I.; Gadyatskii, V.G.

    1992-12-31

    The least reliable components of the cars which receive and transport incandescent coke are the lining plates. This applies to both the quenching cars used for wet quenching and the hot-coke cars used in the dry cooling process. Technical advances have been described whereby the life of car linings is prolonged by increasing heat emission from the lining plate surfaces. As the heat emission level is enhanced the mean plate temperature is lowered and the lining life thereby prolonged; moreover, the between-servicings period is prolonged. This involves providing fins on the non-working (outer) plate surfaces. The problem of optimizing the size and shape of the fins with reference to heat emission remains unsolved: the requirement is maximum heat emission from plates of a given weight, or conversely minimum plate weight for a given heat emission level. 6 refs., 3 figs.

  18. An atlas of Doppler emission-line tomography of cataclysmic variable stars

    NASA Technical Reports Server (NTRS)

    Kaitchuck, Ronald H.; Schlegel, Eric M.; Honeycutt, R. Kent; Horne, Keith; Marsh, T. R.; White, J. C., II; Mansperger, Cathy S.

    1994-01-01

    Doppler emission-line tomography is a technique similar to medical tomography. In this atlas the emission-line profiles of cataclysmic variable stars, seen at different orbital phases, are transformed into velocity space images. This transformation makes many of the complex line profile changes easier to interpret. The emission contributions of the disk and the s-wave are clearly separated in these images, and any emission from the stream and the secondary star can often be identified. In this atlas, Doppler tomograms of Hbeta, He I lambda 4471, and He II lambda 4686 emission lines of 18 cataclysmic variable stars are presented. The Doppler images provide insights into the individual systems and a better technique for measuring and radial velocity amplitude of the white dwarf.

  19. Links Between Emission Line Properties of AGN and Their X-ray SED Components

    NASA Astrophysics Data System (ADS)

    Ward, Martin; Done, C.; Gelbord, J.; Hutton, S.; Jin, C.

    2010-03-01

    We have produced SEDs from 1 micron to 10keV, for a sample of about 50 AGN based on observations with XMM-Newton, including UV points from the optical monitor, and the SDSS. Using detailed spectral fitting techniques, we quantify the contributions from an accretion disc, a hot Compton component, and a power-law, including the effects of absorption. From the optical spectra we measure the principal emission line diagnostics of conditions within the BLR, NLR and the highly ionised regions. By our decomposition of the X-ray to optical continuum into its constituent components, and using correlations with the optical emission lines, we are able to identify the strongest links. From this understanding of how emission lines respond to the separate components of the ionising continuum, we can better explain the wide range of properties from narrowest line Seyfert 1s up to those displaying exceptionally broad emission lines.

  20. Cosmic rays and the emission line regions of active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Ferland, G. J.; Mushotzky, R. F.

    1984-01-01

    The effects that the synchrotron emitting relativistic electrons could have on the emission line regions which characterize active nuclei are discussed. Detailed models of both the inner, dense, broad line region and the outer, lower density, narrow line region are presented, together with the first models of the optically emitting gas often found within extended radio lobes. If the relativistic gas which produces the synchrotron radio emission is mixed with the emission line region gas then significant changes in the emission line spectrum will result. The effects of the synchrotron emitting electrons on filaments in the Crab Nebula are discussed in an appendix, along with a comparison between the experimental calculations, which employ the mean escape probability formalism, and recent Hubbard and Puetter models.

  1. Data-driven dissection of emission-line regions in Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Villarroel, Beatriz; Korn, Andreas J.

    2016-11-01

    Aims: Indirectly resolving the line-emitting gas regions in distant active galactic nuclei (AGN) requires both high-resolution photometry and spectroscopy (i.e. through reverberation mapping). Emission in AGN originates on widely different scales; the broad-line region (BLR) has a typical radius less than a few parsec, the narrow-line region (NLR) extends out to hundreds of parsecs. But emission also appears on large scales from heated nebulae in the host galaxies (tenths of kpc). Methods: We propose a novel, data-driven method based on correlations between emission-line fluxes to identify which of the emission lines are produced in the same kind of emission-line regions. We tested the method on Seyfert galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) and Galaxy Zoo project. Results: We demonstrate the usefulness of the method on Seyfert-1s and Seyfert-2 objects, showing similar narrow-line regions (NLRs). Preliminary results from comparing Seyfert-2s in spiral and elliptical galaxy hosts suggest that the presence of particular emission lines in the NLR depends both on host morphology and eventual radio-loudness. Finally, we explore an apparent linear relation between the final correlation coefficient obtained from the method and time lags as measured in reverberation mapping for Zw229-015.

  2. 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.

  3. Variation of Emission Line Width in Mid- and High-Latitude Corona

    NASA Astrophysics Data System (ADS)

    Prasad, S. Krishna; Singh, Jagdev; Banerjee, D.

    2013-02-01

    Spectroscopic studies of the solar corona, using the high spatial and spectral resolution 25-cm coronagraph at the Norikura Solar Observatory for equatorial off-limb observations, indicated that the variation of radiance and line width with height is different for different temperature lines. The line width of the forbidden red emission line [Fe x] 6374 Å was found to increase with height, and that of the green emission line [Fe xiv] 5303 Å decreased with height. This had been interpreted in terms of the interaction between different temperature plasmas but needed to be confirmed. Further observations were made on several days during 2004, in two emission lines simultaneously covering the mid-latitude and polar regions to investigate the existence of the observed variation in other parts of the solar corona. In this study, we have analysed several raster scans that cover mid- and high-latitude regions of the off-limb corona in all four bright emission lines [Fe x] 6374 Å, [Fe xi] 7892 Å, [Fe xiii] 10747 Å, and [Fe xiv] 5303 Å. We find that the FWHM of the red line increases with height and that of the green line decreases with height, similar to the observations in the equatorial regions. The line widths are higher in the polar regions for all of the observed emission lines except the green line. Higher values of FWHM in polar regions may imply higher non-thermal velocities, which could be further linked to a non-thermal source powering the solar-wind acceleration, but the reason for the behaviour of the green emission line remains to be explored.

  4. On the emission-line response to continuum variations in the Seyfert galaxy NGC 5548

    NASA Astrophysics Data System (ADS)

    Netzer, Hagai; Maoz, Dan

    1990-12-01

    The two optical monitoring groups which have recently attempted to ascertain the continuum and emission-line variations in the Seyfert galaxy NGC 5548 have reported apparently contradictory results for the delay of H-beta variations with respect to the continuum. The measurements of Clavel et al. (1991) are presently used to demonstrate that the emission-line lag behind continuum variations depends on the continuum variability time-scale in this object, in the sense that continuum variations with larger time-scales yield larger emission-line lags. Monte Carlo simulations are used to show that there is at least one possible model which can reproduce the two differing delays.

  5. Influence of self-absorption on plasma diagnostics by emission spectral lines.

    PubMed

    Gudimenko, Evgueni; Milosavljević, Vladimir; Daniels, Stephen

    2012-06-04

    Accurate optical emission spectroscopy (OES) measurements are necessary for plasma semiconductor processing and for optical emission analysis. In this paper we investigate the effects of self-absorption on the most important neutral Argon spectra lines. One of these Argon spectral lines (750 nm) is frequently used for actinometry. The experiment is performed in a reactive ion etch (RIE) capacitively coupled plasma (CCP) system. A comprehensive design of experiments has been created to establish all plasma conditions, power, pressure and gas flow rate which affect the Argon emission intensity by self-absorption. The results are then compared to theoretical calculated line ratios.

  6. Redshifts of Emission-Line Objects in the Hubble Ultra Deep Field

    NASA Astrophysics Data System (ADS)

    Xu, Chun; Pirzkal, Norbert; Malhotra, Sangeeta; Rhoads, James E.; Mobasher, Bahram; Daddi, Emanuele; Gronwall, Caryl; Hathi, Nimish P.; Panagia, Nino; Ferguson, Henry C.; Koekemoer, Anton M.; Kümmel, Martin; Moustakas, Leonidas A.; Pasquali, Anna; di Serego Alighieri, Sperello; Vernet, Joel; Walsh, Jeremy R.; Windhorst, Rogier; Yan, Haojing

    2007-07-01

    We present redshifts for 115 emission-line objects in the Hubble Ultra Deep Field identified through the Grism ACS Program for Extragalactic Science (GRAPES) project using the slitless grism spectroscopy mode of the Advanced Camera for Surveys on the Hubble Space Telescope (HST). The sample was selected by an emission-line search on all extracted one-dimensional GRAPES spectra. We identify the emission lines using line wavelength ratios where multiple lines are detected in the grism wavelength range (5800 Å<~λ<~9600 Å), and using photometric redshift information where multiple lines are unavailable. We then derive redshifts using the identified lines. Our redshifts are accurate to δz~0.009, based on both statistical uncertainty estimates and comparison with published ground-based spectra. Over 40% of our sample is fainter than typical magnitude limits for ground-based spectroscopy (with iAB>25 mag). Such emission lines would likely remain undiscovered without our deep survey. The emission-line objects fall into three categories: (1) most are low- to moderate-redshift galaxies (0<=z<=2), including many actively star-forming galaxies with strong H II regions; (2) nine are high-redshift (4<=z<=7) Lyα emitters; and (3) at least three are candidate active galactic nuclei.

  7. Optical emission-line properties of evolved galactic supernova remnants

    NASA Technical Reports Server (NTRS)

    Fesen, R. A.; Blair, W. P.; Kirshner, R. P.

    1985-01-01

    New optical spectrophotometric data are presented for the supernova remnants CTB 1, OA 184, VRO 42.05.01, S147, the Monoceros Loop, G206.9 + 2.3, and G65.3 + 5.7. These data are combined with published spectral data to study some of the general properties of evolved galactic supernova remnants. It is found that (1) O I and O II forbidden line strengths, when used in conjunction with the usual H-alpha S II forbidden line ratio test, provide an excellent additional diagnostic for discriminating remnants from H II regions; (2) the line ratios H-alpha forbidden line N II, H-alpha forbidden line S II, and forbidden line S II 6717/6731 A generally do not vary substantially among the filaments of an individual remnant; and (3) the observed correlation of forbidden line N II/H-alpha with S II forbidden line 6717/6731 A in remnants is the result of observational selection rather than of evolutionary effects. A galactic nitrogen abundance gradient of d log (N/H)/dR = -0.088 dex/kpc, which is in agreement with that derived from H II regions. However, no abundance gradients for oxygen or sulfur are indicated from the remnant data.

  8. The unusual emission line spectrum of I Zw 1

    NASA Astrophysics Data System (ADS)

    Joly, Monique; Véron-Cetty, M.-P.; Véron, P.

    2004-11-01

    A detailed analysis of the spectrum of I Zw 1 shows that the Narrow Line Region, unlike that of most Seyfert 1 galaxies, is a very low excitation region dominated by both permitted and forbidden Fe II lines. The physical conditions in this region are discussed.

  9. Laboratory Measurements of the X-ray Line Emission from Neon-like Fe XVII

    NASA Technical Reports Server (NTRS)

    Brown, G. V.; Beiersdorfer, P.; Chen, H.; Scofield, J. H.; Boyce, K. R.; Kelley, R. L.; Kilbourne, C. A.; Porter, F. S.; Gu, M. F.; Kahn, S. M.

    2006-01-01

    We have conducted a systematic study of the dominant x-ray line emission from Fe XVII. These studies include relative line intensities in the optically thin limit, intensities in the presence of radiation from satellite lines from lower charge states of iron, and the absolute excitation cross sections of some of the strongest lines. These measurements were conducted at the Lawrence Livermore National Laboratory electron beam ion trap facility using crystal spectrometers and a NASA-Goddard Space Flight Center microcalorimeter array.

  10. Evidence for Supermassive Black Holes in Active Galactic Nuclei from Emission-Line Reverberation

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Wandel, Amri

    2000-01-01

    Emission-line variability data for Seyfert 1 galaxies provide strong evidence for the existence of supermassive black holes in the nuclei of these galaxies and that the line-emitting gas is moving in the gravitational potential of that black hole. The time-delayed response of the emission lines to continuum variations is used to infer the size of the line-emitting region, which is then combined with measurements of the Doppler widths of the variable line components to estimate a virial mass. la the case of the best-studied galaxy, NGC 5548, various emission lines spanning an order of magnitude in distance from the central source show the expected V proportional to r(sup -l/2) correlation between distance and line width and are thus consistent with a single value for the mass. Two other Seyfert galaxies, NGC 7469 and 3C 390.3, show a similar relationship. We compute the ratio of luminosity to mass for these three objects and the narrow-line Seyfert I galaxy NGC 4051 and find that the gravitational force on the line-emitting gas is much stronger than radiation pressure. These results strongly support the paradigm of gravitationally bound broad emission line region clouds.

  11. Evidence for Supermassive Black Holes in Active Galactic Nuclei from Emission-Line Reverberation

    NASA Technical Reports Server (NTRS)

    Peterson, Bradley M.; Wandel, Amri

    2000-01-01

    Emission-line variability data for Seyfert 1 galaxies provide strong evidence for the existence of supermassive black holes in the nuclei of these galaxies and that the line-emitting gas is moving in the gravitational potential of that black hole. The time-delayed response of the emission lines to continuum variations is used to infer the size of the line-emitting region, which is then combined with measurements of the Doppler widths of the variable line components to estimate a virial mass. la the case of the best-studied galaxy, NGC 5548, various emission lines spanning an order of magnitude in distance from the central source show the expected V proportional to r(sup -l/2) correlation between distance and line width and are thus consistent with a single value for the mass. Two other Seyfert galaxies, NGC 7469 and 3C 390.3, show a similar relationship. We compute the ratio of luminosity to mass for these three objects and the narrow-line Seyfert I galaxy NGC 4051 and find that the gravitational force on the line-emitting gas is much stronger than radiation pressure. These results strongly support the paradigm of gravitationally bound broad emission line region clouds.

  12. Using Strong Solar Coronal Emission Lines as Coronal Flux Proxies

    NASA Technical Reports Server (NTRS)

    Falconer, David A.; Jordan, Studart D.; Davila, Joseph M.; Thomas, Roger J.; Andretta, Vincenzo; Brosius, Jeffrey W.; Hara, Hirosha

    1997-01-01

    A comparison of Skylab results with observations of the strong EUV lines of Fe XVI at 335 A and 361 A from the Goddard Solar EUV Rocket Telescope and Spectrograph (SERTS) flight of 1989 suggests that these lines, and perhaps others observed with SERTS, might offer good proxies for estimating the total coronal flux over important wavelength ranges. In this paper, we compare SERTS observations from a later, 1993 flight with simultaneous cospatial Yohkoh soft X-ray observations to test this suggestion over the energy range of the Soft X-ray Telescope (SXT) on Yohkoh. Both polynomial and power-law fits are obtained, and errors are estimated, for the SERTS lines of Fe XVI 335 A and 361 A, Fe XV 284 A and 417 A, and Mg IX 368 A. It is found that the power-law fits best cover the full range of solar conditions from quiet Sun through active region, though not surprisingly the 'cooler' Mg IX 368 A line proves to be a poor proxy. The quadratic polynomial fits yield fair agreement over a large range for all but the Mg IX line, but the linear fits fail conspicuously when extrapolated into the quiet Sun regime. The implications of this work for the He 11 304 A line formation problem are briefly considered. The paper concludes with a discussion of the value of these iron lines observed with SERTS for estimating stellar coronal fluxes, as observed for example with the EUVE satellite.

  13. Using Strong Solar Coronal Emission Lines as Coronal Flux Proxies

    NASA Technical Reports Server (NTRS)

    Falconer, David A.; Jordan, Studart D.; Davila, Joseph M.; Thomas, Roger J.; Andretta, Vincenzo; Brosius, Jeffrey W.; Hara, Hirosha

    1997-01-01

    A comparison of Skylab results with observations of the strong EUV lines of Fe XVI at 335 A and 361 A from the Goddard Solar EUV Rocket Telescope and Spectrograph (SERTS) flight of 1989 suggests that these lines, and perhaps others observed with SERTS, might offer good proxies for estimating the total coronal flux over important wavelength ranges. In this paper, we compare SERTS observations from a later, 1993 flight with simultaneous cospatial Yohkoh soft X-ray observations to test this suggestion over the energy range of the Soft X-ray Telescope (SXT) on Yohkoh. Both polynomial and power-law fits are obtained, and errors are estimated, for the SERTS lines of Fe XVI 335 A and 361 A, Fe XV 284 A and 417 A, and Mg IX 368 A. It is found that the power-law fits best cover the full range of solar conditions from quiet Sun through active region, though not surprisingly the 'cooler' Mg IX 368 A line proves to be a poor proxy. The quadratic polynomial fits yield fair agreement over a large range for all but the Mg IX line, but the linear fits fail conspicuously when extrapolated into the quiet Sun regime. The implications of this work for the He 11 304 A line formation problem are briefly considered. The paper concludes with a discussion of the value of these iron lines observed with SERTS for estimating stellar coronal fluxes, as observed for example with the EUVE satellite.

  14. 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

  15. Al-26: A galactic source of gamma ray line emission

    NASA Technical Reports Server (NTRS)

    Ramaty, R.; Lingenfelter, R. E.

    1976-01-01

    It is shown that Al26 is a very good candidate for producing a detectable gamma-ray line, and that this line is not only intense but also very narrow. By examining the chart of nuclides for other radioactive isotopes which could produce hiterto unnoticed gamma-ray lines following nucleosynthesis, it is found that for mass numbers less than 60, the isotopes Na22, Al26, K40, Ar42, Ti44, Sc46, Mn54, Co56, Co57, Co58, Co60 and Fe60 are the only ones with sufficiently long half lives (70) days to produce gamma rays in optically thin regions.

  16. A Suzaku Observation of the Neutral Fe-line Emission from RCW 86

    NASA Technical Reports Server (NTRS)

    Ueno, Masaru; Sato, Rie; Kataoka, Jun; Bamba, Aya; Harrus, Ilana; Hiraga, Junko; Hughes, John P.; Kilbourne, Caroline A.; Koyama, Katsuji; Kokubun, Motohide; hide

    2007-01-01

    The newly operational X-ray satellite Suzaku observed the supernova remnant (SNR) RCW 86 in February 2006 to study the nature of the 6.4 keV emission line first detected with the Advanced Satellite for Cosmology and Astronomy (ASCA). The new data confirms the existence of the line, localizing it for the first time inside a low temperature emission region and not at the locus of the continuum hard X-ray emission. We also report the first detection of a 7.1 keV line that we interpret as the K(beta) emission from neutral or low-ionized iron. The Fe-K line features are consistent with a non-equilibrium plasma of Fe-rich ejecta with n(sub e) less than or approx. equal to 10(exp 9)/cu cm s and kT(sub e) > 1 keV. We found a sign that Fe K(alpha) line is intrinsically broadened 47 (35-57) eV (99% error region). Cr-K line is also marginally detected, which is supporting the ejecta origin for the Fe-K line. By showing that the hard continuum above 3 keV has different spatial distribution from the Fe-K line, we confirmed it to be synchrotron X-ray emission.

  17. 2D Emission Line Galaxies in the Faint Infrared Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Pirzkal, Nor; Ryan, Russell E.; Rothberg, Barry; Meurer, Gerhardt R.; Malhotra, Sangeeta; Rhoads, James E.; Koekemoer, Anton M.; Finkelstein, Steven; Grogin, Norman A.

    2015-08-01

    The Faint Infrared Galaxy Survey (FIGS) provides us with a unique opportunity to identify emission line galaxies. Emission lines such as [OII], [OIII], Hα and Lya lines can be identified in the FIGS slitless spectroscopic observations down to faint line fluxes of a few times 10-17 erg/s/cm2. Crucially, the use of multiple observations, taken at different position angles on the sky allows us to accurately determine the location of these star forming regions within individual galaxies using the Emission Line 2D (EM2D) method. Our ability to detect high equivalent width lines independently of any host galaxies allows us to search for naked emission line objects. Combining this method with the wavelength coverage of the G102 grism, we are able to identify emission line objects using [OII] and [OIII], and Hα over 0.2 < z < 2 and using Lyman alpha from 6 < z < 8. Here, we present the first results on star forming galaxies selected using this method and demonstrate the wealth of data to be expected from the FIGS project.

  18. The MeerKAT Karoo Array Telescope and its HI Emission Line Surveys

    NASA Astrophysics Data System (ADS)

    de Blok, W. J. G.

    2011-12-01

    This contribution gives a short overview of the MeerKAT Karoo Array Telescope, the South African Square Kilometre Array Precursor. Some of the key specification and HI emission line science for MeerKAT are described.

  19. A high resolution catalog of emission lines of comet C/2000 WM1 (LINEAR)

    NASA Astrophysics Data System (ADS)

    Picazzio, E.; de Almeida, A.; Andrievskii, S. M.; Churyumov, K. I.; Luk'yanyk, I. V.

    2002-11-01

    Using five high-resolution spectra of comet C/2000 WM1 (LINEAR) obtained Dec. 1 and 2, 2001 (UT) with the Fiber fed Extended Range Optical Spectrograph (FEROS) installed on the 1.52-m reflector of the ESO (Chili, La Silla), we have constructed a catalog of cometary emission lines in this comet. Many of the emission lines of the molecules C2, C3, CN, CH, CH+, NH2, CO+, H2O+ and presumably CO and C2- were identified in the spectral range 4000-9000 ÅÅ in the comet spectra. The total of number of identified emission lines is 4537: C2 - 2734, NH2 - 1195, CN - 289, C3 - 158, CO - 60, H2O+ - 51, CH - 50, CO+ - 16, CH+ - 8, C2- - 5. Also there are many unidentified emission lines in the comet spectrum.

  20. Observations of the 12.3 micron Mg I emission line during a major solar flare

    NASA Technical Reports Server (NTRS)

    Deming, Drake; Jennings, Donald E.; Osherovich, Vladimir; Wiedemann, Gunter; Hewagama, Tilak

    1990-01-01

    The extremely Zeeman-sensitive 12.32 micron Mg I solar emission line was observed during a 3B/X5.7 solar flare on October 24, 1989. When compared to postflare values, Mg I emission-line intensity in the penumbral flare ribbon was 20 percent greater at the peak of the flare in soft X-rays, and the 12 micron continuum intensity was 7 percent greater. The flare also excited the emission line in the umbra where it is normally absent. The umbral flare emission exhibits a Zeeman splitting 200 G less than the adjacent penumbra, suggesting that it is excited at higher altitude. The absolute penumbral magnetic field strength did not change by more than 100 G between the flare peak and postflare period. However, a change in the inclination of the field lines, probably related to the formation and development of the flare loop system, was seen.

  1. Broad emission lines in the duelling wind model of active galaxies

    NASA Astrophysics Data System (ADS)

    Mobasher, B.; Raine, D. J.

    1989-04-01

    The broad-line emission from clouds formed by the interaction of a nuclear mass outflow and a disk wind is investigated in the context of a quasar model. The line ratios and profiles are shown to be in general agreement with observations. Particular results include: (1) a density range compatible with suggested solutions to the Ly-alpha/H-beta problem which nevertheless yields the correct C III 1909-A flux; (2) broader lines from the inner higher density region despite an accelerated outflow; (3) compatibility between broad-line-region sizes from variability arguments and ionization parameters; and (4) blueshifted line-peaks apparently uncorrelated with line asymmetry.

  2. LZIFU: IDL emission line fitting pipeline for integral field spectroscopy data

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting

    2016-07-01

    LZIFU (LaZy-IFU) is an emission line fitting pipeline for integral field spectroscopy (IFS) data. Written in IDL, the pipeline turns IFS data to 2D emission line flux and kinematic maps for further analysis. LZIFU has been applied and tested extensively to various IFS data, including the SAMI Galaxy Survey, the Wide-Field Spectrograph (WiFeS), the CALIFA survey, the S7 survey and the MUSE instrument on the VLT.

  3. Nonthermal 10 micron CO2 emission lines in the atmospheres of Mars and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, M. A.; Betz, A. L.; Mclaren, R. A.; Townes, C. H.; Sutton, E. C.

    1976-01-01

    Mechanisms are examined for excitation of strong 10-micron CO2 emission lines seen on Mars and Venus. Line absorption of near-infrared solar flux directly by CO2 or H2O with collisional transfer of energy to CO2 are proposed as likely excitation mechanisms. Altitudes for peak 10-micron emission are estimated to be near 80 km for Mars and 120 km for Venus.

  4. Non-thermal 10 micrometers CO2 emission lines in the atmospheres of Mars and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, M. A.

    1975-01-01

    Mechanisms for the excitation of strong 10 micrometer CO2 emission lines seen on Mars and Venus are examined. Line absorption of near IR solar flux directly by CO2 or by H2O with collisional transfer of energy to CO2 are proposed as likely excitation mechanisms. Altitudes for peak 10 micrometer emission are estimated to be near 80 km for Mars and 120 km for Venus.

  5. Search with Copernicus for ultraviolet emission lines in the planetary nebula NGC 3242

    NASA Technical Reports Server (NTRS)

    Schwartz, R. D.; Snow, T. P., Jr.; Upson, W. L., II

    1978-01-01

    The high-excitation planetary nebula NGC 3242 has been observed with the ultraviolet telescope-spectrometer aboard Copernicus. Wavelength intervals corresponding to the emission lines of O VI at 1032 A, He II at 1085 A, Si III at 1206 A, and N V at 1239 A have been scanned. Upper limits to the observed fluxes are reported and compared with predicted emission-line fluxes from this object.

  6. Search with Copernicus for ultraviolet emission lines in the planetary nebula NGC 3242

    NASA Technical Reports Server (NTRS)

    Schwartz, R. D.; Snow, T. P., Jr.; Upson, W. L., II

    1978-01-01

    The high-excitation planetary nebula NGC 3242 has been observed with the ultraviolet telescope-spectrometer aboard Copernicus. Wavelength intervals corresponding to the emission lines of O VI at 1032 A, He II at 1085 A, Si III at 1206 A, and N V at 1239 A have been scanned. Upper limits to the observed fluxes are reported and compared with predicted emission-line fluxes from this object.

  7. Emission Line Spectra in the Soft X-Ray Region 20-75 (Angstrom)

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Chen, H; Behar, E; Kahn, S M

    2002-06-18

    As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, we studied emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region. Here we present observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 {angstrom} to illustrate our work.

  8. Emission Line Spectra in the Soft X-ray Region 20 - 75 Angstroms

    NASA Technical Reports Server (NTRS)

    Lepson, J. K.; Beiersdorfer, P.; Chen, H.; Behar, E.; Kahn, S. M.

    2002-01-01

    As part of a project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EDIT-II, emission lines of argon and sulfur in the soft X-ray and extreme ultraviolet region were studied. Observations of Ar IX through Ar XVI and S VII through S XIV between 20 and 75 Angstrom are presented to illustrate our work.

  9. Remote Sensing of Nitrous Oxide and Methane Using Emission Lines of a CO Overtone Laser

    NASA Astrophysics Data System (ADS)

    Ionin, A. A.; Klimachev, Yu. M.; Kozlov, A. Yu.; Kotkov, A. A.; Romanovskii, O. A.; Kharchenko, O. V.; Yakovlev, S. V.

    2014-05-01

    We have conducted laboratory experiments on remote sensing of methane in the 3.440 μm region and nitrous oxide in the 3.877 μm region, using emission lines of a CO overtone laser in the differential absorption method. We present the results of measurements of absorption and extinction of the emission lines from an CO overtone laser in the region of selected sensing wavelengths in mixtures with the analyte gases for different experimental configurations.

  10. Theoretical quasar emission-line ratios. VII - Energy-balance models for finite hydrogen slabs

    NASA Technical Reports Server (NTRS)

    Hubbard, E. N.; Puetter, R. C.

    1985-01-01

    The present energy balance calculations for finite, isobaric, hydrogen-slab quasar emission line clouds incorporate probabilistic radiative transfer (RT) in all lines and bound-free continua of a five-level continuum model hydrogen atom. Attention is given to the line ratios, line formation regions, level populations and model applicability results obtained. H lines and a variety of other considerations suggest the possibility of emission line cloud densities in excess of 10 to the 10th/cu cm. Lyman-beta/Lyman-alpha line ratios that are in agreement with observed values are obtained by the models. The observed Lyman/Balmer ratios can be achieved with clouds whose column depths are about 10 to the 22nd/sq cm.

  11. Analytic Inversion of Emission Lines of Arbitrary Optical Depth for the Structure of Supernova Ejecta

    NASA Astrophysics Data System (ADS)

    Ignace, R.; Hendry, M. A.

    2000-07-01

    We derive a method for inverting emission-line profiles formed in supernova ejecta. The derivation assumes spherical symmetry and homologous expansion [i.e., v(r)~r], is analytic, and even takes account of occultation by a pseudophotosphere. Previous inversion methods have been developed that are restricted to optically thin lines, but the particular case of homologous expansion permits an analytic result for lines of arbitrary optical depth. In fact, we show that the quantity that is generically retrieved is the run of line intensity Iλ with radius in the ejecta. This result is quite general and so could be applied to resonance lines, recombination lines, etc. As a specific example, we show how to derive the run of (Sobolev) optical depth τλ with radius in the case of a pure resonance scattering emission line.

  12. Far-infrared line emission from the galaxy. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Stacey, G. J.

    1985-01-01

    The diffuse 157.74 micron (CII) emission from the Galaxy was sampled at several galactic longitudes near the galactic plane including complete scan across the plane at (II) = 2.16 deg and (II) = 7.28 deg. The observed (CII) emission profiles follow closely the nearby (12)CO (J=1to0) emission profiles. The (CII) emission probably arises in neutral photodissociation regions near the edges of giant moleclar clouds (GMC's). These regions have densities of approximately 350 cm(-3) and temperatures of approximately 300 K, and amount to 4x10(8) solar mass of hydrogen in the inner Galaxy. The total 157.74 micron luminosity of the Galaxy is estimated to be 6x10(7) solar luminosity. Estimates were also made of the galactic emission in other far-infrared (FIR) cooling lines. The (CII) line was found to be the dominant FIR emission line from the galaxy and the primary coolant for the warm neutral gas near the galactic plane. Other cooling lines predicted to be prominent in the galactic spectrum are discussed. The 145.53 micron (OI) emission line from the Orion nebula was also measured.

  13. Consistency of spherical, gravity-dominated dynamics with quasar high-ionization emission-line profiles

    NASA Technical Reports Server (NTRS)

    Kallman, T. R.; Wilkes, B. J.; Krolik, J. H.; Green, Richard

    1993-01-01

    Line profile data are used to test a simple kinematic model - spherically symmetric gravitational free fall - in which the number of free parameters is limited by requiring physical self-consistency. The predictions of this model are fitted to high-resolution spectra of the stronger rest-frame UV emission lines in 12 quasars with z of about 2. It is found that if all the lines are radiated predominantly from the illuminated faces of the emission-line clouds, the profiles of Ly-alpha, N V 1240 A, and C IV 1549 A can be simultaneously well fitted with very similar parameters for all 12 quasars. It is concluded that spherically symmetric gravitational free fall does not correctly describe the dynamics of quasar broad emission-line regions.

  14. Resonance Ionization Laser Mass Spectrometry: New possibilities for on-line analysis of waste incinerator emissions

    SciTech Connect

    Zimmermann, Ralf; Rohwer, Egmont R.; Heger, Hans Joerg; Schlag, Edward W.; Kettrup, Antonius; Gilch, Gerhard; Lenoir, Dieter; Boesl, Ulrich

    1997-01-15

    A concept for the use of Resonance Ionization Laser Mass Spectrometry for on-line emission analysis of chlorinated aromatic compounds in waste incinerator flue gas is presented. New analytical results suggest that low chlorinated benzenes can be used as indicator parameter for dioxin emissions.

  15. A spectroscopic survey of case emission-line galaxies in the direction of the Bootes void

    NASA Astrophysics Data System (ADS)

    Tifft, William G.; Kirshner, Robert P.; Moody, J. Ward; Gregory, Stephen A.

    1986-11-01

    Redshifts are reported for 44 objects in the list of emission-line objects published by Sanduleak and Pesch in 1982. Two or these are found to be high-redshift quasars, three are galactic stars, three are galaxies with absorption lines only, five are unidentified objects with no emission lines, and the remaining 31 are emission-line galaxies. A wide variety of emission lines strengths is found for each of the Sanduleak and Pesch emission classes except the strongest. The estimated redshifts for galaxies given by Sanduleak and Pesch correlate well with the measured redshifts. The distribution of the emission line galaxies is not homogeneous and is similar to that of galaxies from the CfA survey in the overlapping region. Seven of the galaxies are found near the boundaries of the large Bootes void, and two lie within the void boundaries drawn by Kirshner and colleagues in 1983. The question of whether the void could be populated with low-luminosity galaxies remains unanswered.

  16. [Status and needs research for on-line monitoring of VOCs emissions from stationary sources].

    PubMed

    Wang, Qiang; Zhou, Gang; Zhong, Qi; Zhao, Jin-Bao; Yang, Kai

    2013-12-01

    Based on atmospheric volatile organic compounds (VOCs) pollution control requirements during the twelfth-five year plan and the current status of monitoring and management in the world, instrumental architecture and technical characteristics of continuous emission monitoring systems (CEMS) for VOCs emission from stationary sources are investigated and researched. Technological development needs of VOCs emission on-line monitoring techniques for stationary sources in China are proposed from the system sampling pretreatment technology and analytical measurement techniques.

  17. Herschel observations of FIR emission lines in brightest cluster galaxies

    NASA Astrophysics Data System (ADS)

    Edge, A. C.; Oonk, J. B. R.; Mittal, R.; Allen, S. W.; Baum, S. A.; Böhringer, H.; Bregman, J. N.; Bremer, M. N.; Combes, F.; Crawford, C. S.; Donahue, M.; Egami, E.; Fabian, A. C.; Ferland, G. J.; Hamer, S. L.; Hatch, N. A.; Jaffe, W.; Johnstone, R. M.; McNamara, B. R.; O'Dea, C. P.; Popesso, P.; Quillen, A. C.; Salomé, P.; Sarazin, C. L.; Voit, G. M.; Wilman, R. J.; Wise, M. W.

    2010-07-01

    The question of how much gas cools in the cores of clusters of galaxies has been the focus of many, multiwavelength studies in the past 30 years. In this letter we present the first detections of the strongest atomic cooling lines, [Cii], [Oi] and [Nii] in two strong cooling flow clusters, A1068 and A2597, using Herschel-PACS. These spectra indicate that the substantial mass of cold molecular gas (> 109 M_⊙) known to be present in these systems is being irradiated by intense UV radiation, most probably from young stars. The line widths of these FIR lines indicate that they share dynamics similar but not identical to other ionised and molecular gas traced by optical, near-infrared and CO lines. The relative brightness of the FIR lines compared to CO and FIR luminosity is consistent with other star-forming galaxies indicating that the properties of the molecular gas clouds in cluster cores and the stars they form are not unusual. These results provide additional evidence for a reservoir of cold gas that is fed by the cooling of gas in the cores of the most compact clusters and provide important diagnostics of the temperature and density of the dense clouds this gas resides in. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  18. Contribution to the Interpretation of Emission-line spectra in Ionised Nebulae

    NASA Astrophysics Data System (ADS)

    Rola, C. S.

    1995-05-01

    The study of ionised nebulae from their emission-line intensities is the aim of this work. It concerns two complementary aspects. Firstly, we have studied the influence of the emission-line detection and measurement procedures in the values of the measured intensities. Secondly, we have developed diagnostic methods for the determination of the nature and physical properties of emission-line objects, using a minimum number of line intensities. Detailed simulations of the emission-line detection and intensity measurement procedures allowed us to estimate the errors committed in the intensity measurement of lines with low signal-to-noise ratio. Obtained results permitted us to show the existence of a bias in the measured intensities distribution and to determine a model for it. Furthermore, we determined analytically the probability distribution function of a intensity lines ratio. In this context, we have studied the effect of uncertainties in the intensity measures, and of temperature fluctuations in the determination of the C/O abundance ratio in planetary nebulae. With the purpose of determining the characteristics and the nature of emission-line objects having only a few line intensities available, we calculated the upper limits for photoionisation by OB stars in diagnostic diagrams. For this we build an extensive grid of photoionisation models covering a wide range of physical conditions in H II regions. The results obtained were used in the determination of the nature of the "Canada-France Redshift Survey" emission-line field galaxies, showing the importance of this type of diagnostic in deep redshift surveys.

  19. 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

  20. ACS Grism Parallel Survey of Emission- line Galaxies at Redshift z Apl 7

    NASA Astrophysics Data System (ADS)

    Yan, Lin

    2002-07-01

    We propose an ACS grism parallel survey to search for emission-line galaxies toward 50 random lines of sight over the redshift interval 0 < z Apl 7. We request ACS parallel observations of duration more than one orbit at high galactic latitude to identify 300 HAlpha emission-line galaxies at 0.2 Apl z Apl 0.5, 720 O IILambda3727 emission-line galaxies at 0.3 Apl z Apl 1.68, and Apg 1000 Ly-alpha emission-line galaxies at 3 Apl z Apl 7 with total emission line flux f Apg 2* 10^-17 ergs s^-1 cm^-2 over 578 arcmin^2. We will obtain direct images with the F814W and F606W filters and dispersed images with the WFC/G800L grism at each position. The direct images will serve to provide a zeroth order model both for wavelength calibration of the extracted 1D spectra and for determining extraction apertures of the corresponding dispersed images. The primary scientific objectives are as follows: {1} We will establish a uniform sample of HAlpha and O II emission-line galaxies at z<1.7 in order to obtain accurate measurements of co-moving star formation rate density versus redshift over this redshift range. {2} We will study the spatial and statistical distribution of star formation rate intensity in individual galaxies using the spatially resolved emission-line morphology in the grism images. And {3} we will study high-redshift universe using Ly-alpha emitting galaxies identified at z Apl 7 in the survey. The data will be available to the community immediately as they are obtained.

  1. A Suzaku search for dark matter emission lines in the X-ray brightest galaxy clusters

    NASA Astrophysics Data System (ADS)

    Urban, O.; Werner, N.; Allen, S. W.; Simionescu, A.; Kaastra, J. S.; Strigari, L. E.

    2015-08-01

    We present the results of a search for unidentified emission lines in deep Suzaku X-ray spectra of the central regions of the X-ray brightest galaxy clusters: Perseus, Coma, Virgo and Ophiuchus. We analyse an optimized energy range (3.2-5.3 keV) that is relatively free of instrumental features, and a plasma emission model incorporating the abundances of elements with the strongest expected emission lines at these energies (S, Ar, Ca) as free parameters. For the Perseus Cluster core, employing this model, we find evidence for an additional emission feature at an energy E=3.51^{+0.02}_{-0.01} keV with a flux of 2.87_{-0.38}^{+0.33}× 10^{-7} photons s^{-1} cm^{-2} arcmin^{-2}. At slightly larger radii, we detect an emission line at 3.59 ± 0.02 keV with a flux of 4.8_{-1.4}^{+1.7}× 10^{-8} photons s^{-1} cm^{-2} arcmin^{-2}. The properties of these features are broadly consistent with previous claims, although the radial variation of the line strength appears in tension with dark matter (DM) decay model predictions. Assuming a decaying DM origin for these features allows us to predict the energies and detected line fluxes for the other clusters. We do not detect an emission feature at the predicted energy and line flux in the Coma, Virgo and Ophiuchus clusters. The formal 99.5 per cent upper limits on the line strengths in each cluster are well below the decaying DM model predictions, disfavouring a decaying DM interpretation. The results of further analysis suggest that systematic effects associated with modelling the spectra for the Perseus Cluster, details of the assumed ionization balance and errors in the predicted spectral line emissivities may be largely responsible for the ˜3.55 keV feature.

  2. The spatial distribution of ultraviolet line and continuum emission in Herbig-Haro objects

    NASA Technical Reports Server (NTRS)

    Lee, M. G.; Boehm, K. H.; Temple, S. D.; Raga, A. C.; Mateo, M. L.

    1988-01-01

    Archival IUE data and monochromatic CCD images in the optical range are used to compare the spatial distribution of UV and optical emission in HH 1, HH 2, HH 24, HH 32, HH 43, and HH 47. For all six objects, the observed UV radiation is shown to originate in the objects themselves. The results indicate that the C IV and semiforbidden emission-line regions are small. Although the continuum in the IUE short-wavelength range displays a distribution that is broader than that of any measured line emission in the UV or optical range, the continuum distribution in the IUE long-wavelength range is quite narrow.

  3. Gamma-ray line emission from 7Li and 7Be production by cosmic-rays

    NASA Astrophysics Data System (ADS)

    Tatischeff, V.; Thibaud, J.-P.; Kiener, J.; Cassé, M.; Vangioni-Flam, E.

    2001-09-01

    We calculate the total γ-ray line emission at ~450 keV that accompanies 7Li and 7Be production by cosmic-ray interactions, including the delayed line emission at 0.478 MeV from 7Be radioactive decay. We present a new γ-ray spectroscopic test which has the potential to give direct information on the nature of the interstellar regions into which 7Be ions propagate and decay. Finally, we evaluate the intensity of the predicted diffuse emission from the central radian of the Galaxy.

  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. BAT AGN spectroscopic survey-II. X-ray emission and high-ionization optical emission lines

    NASA Astrophysics Data System (ADS)

    Berney, Simon; Koss, Michael; Trakhtenbrot, Benny; Ricci, Claudio; Lamperti, Isabella; Schawinski, Kevin; Baloković, Mislav; Crenshaw, D. Michael; Fischer, Travis; Gehrels, Neil; Harrison, Fiona; Hashimoto, Yasuhiro; Ichikawa, Kohei; Mushotzky, Richard; Oh, Kyuseok; Stern, Daniel; Treister, Ezequiel; Ueda, Yoshihiro; Veilleux, Sylvain; Winter, Lisa

    2015-12-01

    We investigate the relationship between X-ray and optical line emission in 340 nearby (z ≃ 0.04) AGN selected above 10 keV using Swift BAT. We find a weak correlation between the extinction corrected [O III] and hard X-ray luminosity (L_[O III]^{int} ∝ L_{14-195}) with a large scatter (RPear = 0.64, σ = 0.62 dex) and a similarly large scatter with the intrinsic 2-10 keV to [O III] luminosities (RPear = 0.63, σ = 0.63 dex). Correlations of the hard X-ray fluxes with the fluxes of high-ionization narrow lines ([O III], He II, [Ne III] and [Ne V]) are not significantly better than with the low-ionization lines (H α, [S II]). Factors like obscuration or physical slit size are not found to be a significant part of the large scatter. In contrast, the optical emission lines show much better correlations with each other (σ = 0.3 dex) than with the X-ray flux. The inherent large scatter questions the common usage of narrow emission lines as AGN bolometric luminosity indicators and suggests that other issues such as geometrical differences in the scattering of the ionized gas or long-term AGN variability are important.

  6. UV emission lines in galactic nuclei: Predictions from the duelling wind model

    NASA Astrophysics Data System (ADS)

    Smith, M. D.; Raine, D. J.

    1986-09-01

    The Duelling Wind Model is used to interpret broad line regions (BLR) in IUE data of source NGC 4151. Line intensities, widths, and response times are all consistent with a 2 million solar mass central engine, an active phase luminosity close to the Eddington limit and a broad line density maximum of 10 to the 12th power cc at a radius of 2 times 10 to the 16th power cm. It is shown how the delayed response of the line emission to the continuum can be used to test the model. Besides a 5 day speed-of-light time lag, the emission line strength responds to the previous 100 to 200 days of nuclear activity (due to the density of the disk wind). This appears in the cross-correlated data of Gaskell and Sparke (1986) and can be distinguished from an alternative explanation, an extended BLR, through the associated response of the line shape and width.

  7. Systematic QSO emission-line velocity shifts and new unbiased redshifts

    NASA Technical Reports Server (NTRS)

    Tytler, David; Fan, Xiao-Ming

    1992-01-01

    A novel method for determining mean line velocities which is an order of magnitude more accurate than past work is presented. Using a large sample of 518 lines from 160 QSOs, it is found that each UV emission line has a well-determined mean velocity, with a surprisingly small QSO-to-QSO dispersion of under 200 km/s. All correlations between emission-line velocities and QSO properties are found to be explained by just three basic correlations. Both N V and Mg II tend to be at less negative velocities in radio-quiet vs radio-loud QSOs, and C IV lines with small equivalent widths are at more negative velocities, probably because of the line asymmetry. The finding of Sargent et al. (1989) that the UV spectral index increases with UV luminosity is confirmed, but their claim that radio-loud and radio-quiet QSOs have different indices is not confirmed.

  8. H{alpha} DOTS: A CATALOG OF FAINT EMISSION-LINE OBJECTS DISCOVERED IN NARROWBAND IMAGES

    SciTech Connect

    Kellar, Jessica A.; Wegner, Gary; Salzer, John J.; Williams, Anna; Gronwall, Caryl E-mail: gaw@northstar.dartmouth.edu E-mail: caryl@astro.psu.edu

    2012-06-15

    During a wide-field narrowband H{alpha} imaging survey, we noted the presence of numerous isolated emission-line point sources in the data. These objects could represent ultra-low-luminosity galaxies at low-redshift (detection via H{alpha}), isolated extragalactic H II regions associated with the galaxy targeted by the original observation, or background galaxies or QSOs where strong emission lines (most often [O III] {lambda}5007) redshift into our narrowband filter. We have carried out a systematic search for these 'H{alpha} dots' in over 200 15 Multiplication-Sign 15 arcmin fields. To date we have cataloged 61 candidate emission-line sources in roughly 11.7 deg{sup 2}. The sample has a median R magnitude of 19.5, and detects objects as faint as R = 22.6. Follow-up spectroscopy reveals that {approx}85% of the candidates are bona fide emission-line objects, with roughly 60% of the real sources being lower-redshift objects (detection via H{alpha}) and 40% being higher-redshift objects detected via [O III] emission or some other emission line. Here we present the results of our initial survey and follow-up spectroscopy. We use our sample to study the properties (including star-formation rates and metal abundances) of low-luminosity star-forming galaxies in the nearby universe and of low-metallicity star-forming galaxies at z Almost-Equal-To 0.33.

  9. A Narrowband Emission-Line Survey of the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Gordon, Alex Jonah Robert; Points, Sean; Smith, Chris; MCELS Team

    2017-01-01

    The Large and Small Magellanic Clouds are unique in providing sites to study the interstellar medium (ISM) and its components at all scales, from small to global. The UM/CTIO Magellanic Cloud Emission-Line Survey (MCELS) began as a deep imaging survey of both of these nearby galaxies in the emission of Hα, [S II], and [O III]. These emission-line images are being used in detailed optical and multi-wavelength studies of planetary nebulae (PNe), H II regions, supernova remnants (SNRs), superbubbles, and supergiant shells. Here we present a deep and wide view of the 104 K ionized gas in the ISM of the Large Magellanic Cloud (LMC) using narrowband filters: Hα and [S II]. We present large-scale continuum subtracted optical emission-line mosaics of the 8x8 deg. central region of the LMC created from the combination of thousands of observations taken over hundreds of nights, providing a detailed view of most of the gaseous extent of the galaxy. With these mosaics in hand we conduct a systematic analysis of the physical conditions of 59 known X-ray SNRs in the LMC. For 50 of these SNRs, Hα and [S II] flux values along with [S II] / Hα emission-line ratios have been derived. All derived [S II] / Hα emission-line ratios ≥ 0.4, strengthening their identification as true remnants. We compare our values to spectroscopic values in the literature.

  10. Temperature measurement of wood flame based on the double line method of atomic emission spectra

    NASA Astrophysics Data System (ADS)

    Hao, Xiaojian; Liu, Zhenhua; Sang, Tao

    2016-01-01

    Aimed at the testing requirement of the transient high temperature in explosion field and the bore of barrel weapon, the temperature measurement system of double line of atomic emission spectrum was designed, the method of flame spectrum testing system were used for experimental analysis. The experimental study of wood burning spectra was done with flame spectrum testing system. The measured spectra contained atomic emission spectra of the elements K, Na, and the excitation ease of two kinds atomic emission spectra was analyzed. The temperature was calculated with two spectral lines of K I 766.5nm and 769.9nm. The results show that, compared with Na, the excitation temperature of K atomic emission spectra is lower. By double line method, the temperature of wood burning is 1040K, and error is 3.7%.

  11. Study of Opacity Effects on Emission Lines at EXTRAP T2R RFP

    NASA Astrophysics Data System (ADS)

    Stancalie, Viorica; Rachlew, Elisabeth

    We have investigated the influence of opacity on hydrogen (H-α and Ly-β) and Li-like oxygen emission lines from the EXTRAP T2R reversed field pinch. We used the Atomic Data Analysis System (AzDAS) based on the escape factor approximation for radiative transfer to calculate metastable and excited population densities via a collisional-radiative model. Population escape factor, emergent escape factor and modified line profiles are plotted vs. optical depth. The simulated emission line ratios in the density/temperature plane are in good agreement with experimental data for electron density and temperature measurements.

  12. Density and temperature diagnostics of solar emission lines from NA VII and AL IX

    NASA Astrophysics Data System (ADS)

    Raju, P. K.; Dwivedi, B. N.; Gupta, Asheesh K.

    1994-02-01

    Line intensity ratios of extreme ultraviolet (EUV) emission lines from Na VII and Al IX have been considered for electron density and temperature determinations within the chromosphere-corona transition region and the corona. The electron pressure within the emission region has been assumed to be a constant parameter. Theoretical line intensities for these ions have been computed using a model solar atmosphere and compared with the values as observed by the Apollo Telescope Mount (ATM) ultraviolet spectrometer. The observed intensities correspond to the average quiet-Sun conditions near solar minimum.

  13. Variability of the emission line fluxes and ratios of HH 1/2

    NASA Astrophysics Data System (ADS)

    Raga, A. C.; Reipurth, B.; Castellanos-Ramírez, Bally, J.

    2016-10-01

    We compare spectrophotometric data of HH 1 and 2 obtained in 1978 (by Brugel et al. 1981a) with the emission line fluxes from calibrated Hubble Space Telescope (HST) images obtained in 1994 and 2014. This comparison shows that the emission line ratios of these objects have remained surprisingly invariant during the past 36 years. On the other hand, the line intensities have indeed changed, with HH 2 brightening by a factor of ≈ 4 and HH 1 becoming ≈ 30% fainter. These results would be consistent with HH 1 and 2 being leading working surfaces of heavy jets travelling into an environment of decreasing (for HH 1) or increasing (HH 2) densities.

  14. The Kinematics of Quasar Broad Emission Line Regions Using a Disk-Wind Model

    NASA Astrophysics Data System (ADS)

    Yong, Suk Yee; Webster, Rachel L.; King, Anthea L.; Bate, Nicholas F.; O'Dowd, Matthew J.; Labrie, Kathleen

    2017-09-01

    The structure and kinematics of the broad line region in quasars are still unknown. One popular model is the disk-wind model that offers a geometric unification of a quasar based on the viewing angle. We construct a simple kinematical disk-wind model with a narrow outflowing wind angle. The model is combined with radiative transfer in the Sobolev, or high velocity, limit. We examine how angle of viewing affects the observed characteristics of the emission line. The line profiles were found to exhibit distinct properties depending on the orientation, wind opening angle, and region of the wind where the emission arises.

  15. The oxygen emission lines in Wolf-Rayet spectra

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Underhill, Anne B.

    1990-01-01

    The statistical equilibrium of oxygen in the line-emitting regions of WR stars is studied using the one-representative point theory of Castor and van Blerkom (1970) for a wider range of the radiation temperature, electron temperature, and electron density. Radiative processes, collisional processes, and electronic recombination are studied for a 59-level model atom. The level populations depart by large factors from those expected for LTE at the electron temperature and electron density. When the parameters have the values found previously by Bhatia and Underhill to be representative for WR stars, the oxygen atoms are strongly concentrated in the lower levels of O(2+), O(3+), and O(4+). The predicted relative energies in typical lines of O III, O IV, and O V for a solar abundance ratio of O to H are compatible with what is observed in WC and WN spectra.

  16. [Fe III] EMISSION LINES IN THE PLANETARY NEBULA NGC 2392

    SciTech Connect

    Zhang, Y.; Chau, W.; Hsia, C.-H.; Kwok, S.; Fang, X.; Liu, X.-W.; Koning, N.

    2012-07-20

    NGC 2392 is a young double-shell planetary nebula (PN). Its intrinsic structure and shaping mechanism are still not fully understood. In this paper we present new spectroscopic observations of NGC 2392. The slits were placed at two different locations to obtain the spectra of the inner and outer regions. Several [Fe III] lines are clearly detected in the inner region. We infer that NGC 2392 might have an intrinsic structure similar to the bipolar nebula Mz 3, which also exhibits a number of [Fe III] lines arising from the central regions. In this scenario, the inner and outer regions of NGC 2392 correspond to the inner lobes and the outer outflows of Mz 3, respectively. We construct a three-dimensional morpho-kinematic model to examine our hypothesis. We also compare the physical conditions and chemical composition of the inner and outer regions, and discuss the implications on the formation of this type of PN.

  17. The IPHAS catalogue of Hα emission-line sources in the northern Galactic plane

    NASA Astrophysics Data System (ADS)

    Witham, A. R.; Knigge, C.; Drew, J. E.; Greimel, R.; Steeghs, D.; Gänsicke, B. T.; Groot, P. J.; Mampaso, A.

    2008-03-01

    We present a catalogue of point-source Hα emission-line objects selected from the INT/WFC Photometric Hα Survey (IPHAS) of the northern Galactic plane. The catalogue covers the magnitude range 13 <= r' <= 19.5 and includes Northern hemisphere sources in the Galactic latitude range -5° < b < 5°. It is derived from ~1500 deg2 worth of imaging data, which represents 80 per cent of the final IPHAS survey area. The electronic version of the catalogue will be updated once the full survey data become available. In total, the present catalogue contains 4853 point sources that exhibit strong photometric evidence for Hα emission. We have so far analysed spectra for ~300 of these sources, confirming more than 95 per cent of them as genuine emission-line stars. A wide range of stellar populations are represented in the catalogue, including early-type emission-line stars, active late-type stars, interacting binaries, young stellar objects and compact nebulae. The spatial distribution of catalogue objects shows overdensities near sites of recent or current star formation, as well as possible evidence for the warp of the Galactic plane. Photometrically, the incidence of Hα emission is bimodally distributed in (r' - i'). The blue peak is made up mostly of early-type emission-line stars, whereas the red peak may signal an increasing contribution from other objects, such as young/active low-mass stars. We have cross-matched our Hα-excess catalogue against the emission-line star catalogue of Kohoutek & Wehmeyer, as well as against sources in SIMBAD. We find that fewer than 10 per cent of our sources can be matched to known objects of any type. Thus IPHAS is uncovering an order of magnitude more faint (r' > 13) emission-line objects than were previously known in the Milky Way.

  18. Line ratios for soft-x-ray emission following charge exchange between O8 + and Kr

    NASA Astrophysics Data System (ADS)

    Seely, D. G.; Andrianarijaona, V. M.; Wulf, D.; Morgan, K.; McCammon, D.; Fogle, M.; Stancil, P. C.; Zhang, R. T.; Havener, C. C.

    2017-05-01

    Lyman spectra and line ratios are reported for soft-x-ray emissions following the charge exchange process in 293, 414, 586, and 1256 km/s O8 + and Kr collisions. Lyman series from Ly-α to Ly-ɛ were resolved for the O7 + ion using a high-resolution x-ray quantum microcalorimeter detector. It is found that the observed line ratios are dependent on the n l distribution of the captured electron, and the Ly-α and Ly-β x-ray emissions are enhanced. Moreover, by comparing the measured line ratios to the constructed theoretical single charge exchange line ratios for O8 ++H , it is suggested that autoionizing double capture plays a significant role in the enhancement of Ly-α and Ly-β emissions for the present system.

  19. Dark matter line emission constraints from NuSTAR observations of the bullet cluster

    SciTech Connect

    Riemer-Sørensen, S.; Wik, D.; Madejski, G.; Molendi, S.; Gastaldello, F.; Harrison, F. A.; Craig, W. W.; Hailey, C. J.; Boggs, S. E.; Christensen, F. E.; Stern, D.; Zhang, W. W.; Hornstrup, A.

    2015-08-27

    Some dark matter candidates, e.g., sterile neutrinos, provide observable signatures in the form of mono-energetic line emission. Here, we present the first search for dark matter line emission in the $3-80\\;\\mathrm{keV}$ range in a pointed observation of the Bullet Cluster with NuSTAR. We do not detect any significant line emission and instead we derive upper limits (95% CL) on the flux, and interpret these constraints in the context of sterile neutrinos and more generic dark matter candidates. NuSTAR does not have the sensitivity to constrain the recently claimed line detection at $3.5\\;\\mathrm{keV}$, but improves on the constraints for energies of $10-25\\;\\mathrm{keV}$.

  20. Dark matter line emission constraints from NuSTAR observations of the bullet cluster

    DOE PAGES

    Riemer-Sørensen, S.; Wik, D.; Madejski, G.; ...

    2015-08-27

    Some dark matter candidates, e.g., sterile neutrinos, provide observable signatures in the form of mono-energetic line emission. Here, we present the first search for dark matter line emission in themore » $$3-80\\;\\mathrm{keV}$$ range in a pointed observation of the Bullet Cluster with NuSTAR. We do not detect any significant line emission and instead we derive upper limits (95% CL) on the flux, and interpret these constraints in the context of sterile neutrinos and more generic dark matter candidates. NuSTAR does not have the sensitivity to constrain the recently claimed line detection at $$3.5\\;\\mathrm{keV}$$, but improves on the constraints for energies of $$10-25\\;\\mathrm{keV}$$.« less

  1. Unidentified Cometary Emission Lines as the Photoluminescence of Frozen Hydrocarbon Particles

    NASA Astrophysics Data System (ADS)

    Simonia, I. A.

    2004-12-01

    We discuss the possible nature of unidentified cometary emission lines. We propose a model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons (PAHs) and acyclic hydrocarbons. We describe the general properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. We compare the positions of unidentified emission lines in the spectrum of Comet 122P/de Vico with the positions of quasi-lines in the photoluminescence spectrum of PAHs that were dissolved in acyclic hydrocarbons at a temperature of 77 K and that constituted a polycrystalline solution. We estimate the detectability of FHP photoluminescence in cometary spectra.

  2. PHYSICAL CONDITIONS IN THE X-RAY EMISSION-LINE GAS IN NGC 1068

    SciTech Connect

    Kraemer, S. B.; Sharma, N.; Turner, T. J.; George, Ian M.; Crenshaw, D. Michael

    2015-01-01

    We present a detailed, photoionization modeling analysis of XMM-Newton/Reflection Grating Spectrometer observations of the Seyfert 2 galaxy NGC 1068. The spectrum, previously analyzed by Kinkhabwala et al., reveals a myriad of soft X-ray emission lines, including those from H- and He-like carbon, nitrogen, oxygen, and neon, and M- and L-shell iron. As noted in the earlier analysis, based on the narrowness of the radiative recombination continua, the electron temperatures in the emission-line gas are consistent with photoionization, rather than collisional ionization. The strengths of the carbon and nitrogen emission lines, relative to those of oxygen, suggest unusual elemental abundances, which we attribute to the star formation history of the host galaxy. Overall, the emission lines are blueshifted with respect to systemic, with radial velocities ∼160 km s{sup –1}, similar to that of [O III] λ5007, and thus consistent with the kinematics and orientation of the optical emission-line gas and, hence, likely part of an active galactic nucleus driven outflow. We were able to achieve an acceptable fit to most of the strong emission lines with a two-component photoionization model, generated with CLOUDY. The two components have ionization parameters and column densities of logU = –0.05 and 1.22 and logN {sub H} = 20.85 and 21.2 and covering factors of 0.35 and 0.84, respectively. The total mass of the X-ray gas is roughly an order of magnitude greater than the mass of ionized gas determined from optical and near-IR spectroscopy, which indicates that it may be the dominant component of the narrow-line region. Furthermore, we suggest that the medium that produces the scattered/polarized optical emission in NGC 1068 possesses similar physical characteristics to those of the more highly ionized of the X-ray model components.

  3. Extended H2 emission line sources from UWISH2

    NASA Astrophysics Data System (ADS)

    Froebrich, D.; Makin, S. V.; Davis, C. J.; Gledhill, T. M.; Kim, Y.; Koo, B.-C.; Rowles, J.; Eislöffel, J.; Nicholas, J.; Lee, J. J.; Williamson, J.; Buckner, A. S. M.

    2015-12-01

    We present the extended source catalogue for the UKIRT Wide Field Infrared Survey for H2 (UWISH2). The survey is unbiased along the inner Galactic Plane from l ≈ 357° to l ≈ 65° and |b| ≤ 1.5° and covers 209 deg2. A further 42.0 and 35.5 deg2 of high dust column density regions have been targeted in Cygnus and Auriga. We have identified 33 200 individual extended H2 features. They have been classified to be associated with about 700 groups of jets and outflows, 284 individual (candidate) planetary nebulae, 30 supernova remnants and about 1300 photodissociation regions. We find a clear decline of star formation activity (traced by H2 emission from jets and photodissociation regions) with increasing distance from the Galactic Centre. About 60 per cent of the detected candidate planetary nebulae have no known counterpart and 25 per cent of all supernova remnants have detectable H2 emission associated with them.

  4. Investigating the Sensitivity of Emission Line Spectra to the Incident SED in Narrow Line Seyferts and LINERs

    NASA Astrophysics Data System (ADS)

    Greene, Christopher; Richardson, Chris T.

    2017-01-01

    This research investigates photoionization models of the Narrow Line Region (NLR) of Seyfert galaxies and Low-Ionization Nuclear Emitting Region (LINER) galaxies with the use of the astrophysical code CLOUDY. Groves et al. 2004 attempted to resolve the apparent uniformity of emission line ratios in the NLR through introducing dusty, radiation pressure-dominated photoionization models of AGN. This model assumed a simple power law relation for the Spectral Energy Distribution (SED). Grupe et al. 2010 found a correlation between αuv and αx, and by constraining αuv as a function of αx we developed a photoionization model for the ionizing spectrum of a typical Seyfert Narrow Line Region. The incident SED is based upon the spectral indices αuv, αx, αox , and the blackbody accretion disk temperature Tbb . We set the value of αox based on the average of data collected in Grupe et al. 2010, and fix the value of αuv to αx based on their linear correlation. To check the validity of our model, simulations were run across a range of blackbody accretion disk temperatures and αx, while fixing the hydrogen density, ionization parameter, and elemental abundance of clouds in the NLR. The emission lines produced by these simulations were plotted using standard diagnostic diagrams and compared to emission line data obtained from the Sloan Digital Sky Survey. Our model produces emission lines without significant variation between simulations with αx = 1.42, 1.17, and 2.19, with Tbb ranging from 104 K to 107 K, except with regard to [O I] λ6300/Hα, where our simulated spectra started to fall on the boundary between Seyferts and LINERs. This leads us to examine the ability of our photoionization model to create emission line spectra that are typical of LINERs, as debate still continues over the primary excitation mechanism for LINERs. To adjust our model to fit LINERs, we lower the value of the ionization parameter and discuss the preliminary results within the context of

  5. Anisotropic. cap alpha. -emission of on-line separated isotopes

    SciTech Connect

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

    1987-12-10

    The technical realization of particle detection at very low temperatures (4K) has made it possible to study for the first time the anisotropic ..cap alpha..-decay of oriented nuclei which have been produced, separated and implanted on line. The measured ..cap alpha..-angular distributions reveal surprising new results on nuclear aspects as well as in solid state physics. The nuclear structure information from these data questions the older ..cap alpha..-decay theoretical interpretation and urges for a reaxamination of the earliest work on anisotropic ..cap alpha..-decay.

  6. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    NASA Astrophysics Data System (ADS)

    Spinoglio, Luigi; Malkan, Matthew A.; Smith, Howard A.; González-Alfonso, Eduardo; Fischer, Jacqueline

    2005-04-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 μm) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). In addition to the seven expected ionic fine-structure emission lines, the OH rotational lines at 79, 119, and 163 μm were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 μm line, when detected, is always in absorption. The observed line intensities were modeled together with ISOShort Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the active galactic nucleus (AGN) component and the starburst component in the circumnuclear ring of ~3 kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a `` big blue bump'' is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Brγ equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low-ionization parameter (U=10-3.5) and low densities (n=100 cm-3) are derived. Combining the AGN and starburst components, we succeeded in modeling the overall UV to far-IR atomic spectrum of NGC 1068, reproducing the line fluxes to within a factor of 2.0 on average with a standard deviation of 1.3, and the overall continuum as the sum of the contribution of the thermal dust emission in the ionized and neutral components. The OH 119 μm emission indicates that the line is collisionally excited and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, nonlocal, non-LTE radiative transfer models. The models indicate that the bulk of the emission

  7. Wide-Field Emission-Line Imaging of Galactic Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Winkler, P. Frank; Smith, R. Chris

    2001-02-01

    We propose to complete narrow-band emission-line imaging of all the southern supernova remnants (SNRs) for which optical emission has been reported. The great majority of these have never been systematically studied using CCDs. Images in Hα, S II, and O III will enable us to distinguish shock-heated SNR filaments from photo-ionized nebulosity and to search for rare, ejecta-dominated filaments. With matched continuum images we will subtract the stars to give pure emission-line images and reveal faint diffuse features. The results will be used in conjunction with X-ray and radio images for multi-wavelength studies of SNRs and the ISM. We plan to assemble an emission-line atlas of SNRs, to be available in both published form and on-line as digital images. This study requires the unique wide field and fast beam of the Schmidt, so we request sufficient time to complete it in the last semester of this instrument's availability. In addition, we plan deep, broad-band imaging of the SN 1006 remnant in attempt at the first measurement of optical synchrotron emission behind an SNR shock. Detection at the level expected from extrapolation of radio and X-ray power-law spectra would support the picture that Fermi acceleration of electrons to TeV energies produces both X-ray emission and cosmic rays, while significant upper limits would raise questions about this picture.

  8. X-RAY EMISSION LINE PROFILES FROM WIND CLUMP BOW SHOCKS IN MASSIVE STARS

    SciTech Connect

    Ignace, R.; Waldron, W. L.; Cassinelli, J. P.; Burke, A. E. E-mail: wwaldron@satx.rr.com E-mail: burke.alexander@gmail.com

    2012-05-01

    The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two-component flow structure of wind and clumps using two 'beta' velocity laws. While individual bow shocks tend to generate double-horned emission line profiles, a group of bow shocks can lead to line profiles with a range of shapes with blueshifted peak emission that depends on the degree of X-ray photoabsorption by the interclump wind medium, the number of clump structures in the flow, and the radial distribution of the clumps. Using the two beta law prescription, the theoretical emission measure and temperature distribution throughout the wind can be derived. The emission measure tends to be power law, and the temperature distribution is broad in terms of wind velocity. Although restricted to the case of adiabatic cooling, our models highlight the influence of bow shock effects for hot plasma temperature and emission measure distributions in stellar winds and their impact on X-ray line profile shapes. Previous models have focused on geometrical considerations of the clumps and their distribution in the wind. Our results represent the first time that the temperature distribution of wind clump structures are explicitly and self-consistently accounted for in modeling X-ray line profile shapes for massive stars.

  9. Dayglow Emission Line Profiles from the Outer Planets Cycle 4-MED Part 2 OF 5414

    NASA Astrophysics Data System (ADS)

    Clarke, John

    1994-01-01

    Recent IUE observations of the H Ly alpha emission line profilefrom Jupiter's dayglow and aurora reveal a substantial line broadening,implying that the observed high brightness is due to resonantscattering of solar emission with a broad line rather than chargedparticle excitation. This may reflect highly energetic processesproducing a 5-10 km/sec suprathermal population of H atoms in Jupiter'supper atmosphere, which in turn may be related to the unresolved questionof the high exospheric temperatures of 400-1200 K detected on all 4 giantplanets during the Voyager encounters. It is clear that if the bright HLy alpha emissions from the outer planets are due mainly to resonantscattering of solar and interplanetary emissions, as observedon Jupiter and Saturn from long term correlations with the solarLy alpha flux, then the lines from all 4 planets must be broad toexplain the observed high albedos. The H Ly alpha lineshapes providea discriminant between the processes of resonant scattering andcharged particle excitation. We propose to obtain high signal to noiseH Ly alpha line profile measurements from Saturn, Uranus, and Neptuneto resolve the questions about the excitation processes for the brightairglow emissions.SATURN PART ONLY - NEPTUNE AND URANUS IN ORIGIAL PROP (5414).

  10. 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.

  11. X-ray narrow emission lines from the nuclear region of NGC 1365

    NASA Astrophysics Data System (ADS)

    Whewell, M.; Branduardi-Raymont, G.; Page, M. J.

    2016-11-01

    Context. NGC 1365 is a Seyfert 2 galaxy with a starburst ring in its nuclear region. In this work we look at the XMM-Newton Reflection Grating Spectrometer (RGS) data from four 2012-13, three 2007 and two 2004 observations of NGC 1365, in order to analyse and characterise in a uniform way the soft X-ray narrow-line emitting gas in the nucleus. Aims: We characterise the narrow-line emitting gas visible by XMM-Newton RGS and make comparisons between the 2012-13 spectra and those from 2004-07, already published. Methods: This source is usually absorbed within the soft X-ray band, with a typical neutral column density of >1.5 × 1023 cm-2, and only one observation of the nine we investigate shows low enough absorption for the continuum to emerge in the soft X-rays. We stack all observations from 2004-07, and separately three of the four observations from 2012-13, analysing the less absorbed observation separately. We first model the spectra using Gaussian profiles representing the narrow line emission. We fit physically motivated models to the 2012-13 stacked spectra, with collisionally ionised components representing the starburst emission and photoionised line emission models representing the AGN line emission. The collisional and photoionised emission line models are fitted together (rather than holding either one constant), on top of a physical continuum and absorption model. Results: The X-ray narrow emission line spectrum of NGC 1365 is well represented by a combination of two collisionally ionised (kT of 220 ± 10 and 570 ± 15 eV) and three photoionised (log ξ of 1.5 ± 0.2, 2.5 ± 0.2, 1.1 ± 0.2) phases of emitting gas, all with higher than solar nitrogen abundances. This physical model was fitted to the 2012-13 stacked spectrum, and yet also fits well to the 2004-07 stacked spectrum, without changing any characteristics of the emitting gas phases. Our 2004-07 results are consistent with previous emission line work using these data, with five additional

  12. Improved And Quality Assessed Emission And Absorption Line Measurements In Sloan Digital Sky Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Oh, Kyuseok; Sarzi, M.; Schawinski, K.; Yi, S. K.

    2011-01-01

    We have established a new database of absorption and emission line measurements from the Sloan Digital Sky Survey 7th data release for the galaxies within a redshift of 0.2. This work used publicly available codes, pPXF(penalized pixel-fitting) and GANDALF(gas and absorption line fitting), to achieve robust spectral fits and reliable measurements. The absorption line strengths measured by SDSS pipeline are seriously contaminated by emission fill-in. We effectively separate emission lines from absorption lines. For instance, this work successfully extract [NI] doublet from Mgb and it leads to more realistic result of alpha enhancement on late-type galaxies compared to the previous database. Besides accurately measuring line strengths, the database will be provided with new parameters that are indicative of line strength measurement quality. Users can build a subset of database optimal for their studies using specific cuts in the fitting quality parameters as well as empirical signal-to-noise. Applying these parameters, we found galaxies with dramatically broad line regions among the galaxies with poor fitting quality parameters. We applied a new continuum finding prescriptions to newly identified BLRs and they turned out to be Seyfert I nuclei.

  13. C IV emission-line properties and systematic trends in quasar black hole mass estimates

    NASA Astrophysics Data System (ADS)

    Coatman, Liam; Hewett, Paul C.; Banerji, Manda; Richards, Gordon T.

    2016-09-01

    Black hole masses are crucial to understanding the physics of the connection between quasars and their host galaxies and measuring cosmic black hole-growth. At high redshift, z ≳ 2.1, black hole masses are normally derived using the velocity width of the C IV λ λ1548, 1550 broad emission line, based on the assumption that the observed velocity widths arise from virial-induced motions. In many quasars, the C IV emission line exhibits significant blue asymmetries (`blueshifts') with the line centroid displaced by up to thousands of km s-1 to the blue. These blueshifts almost certainly signal the presence of strong outflows, most likely originating in a disc wind. We have obtained near-infrared spectra, including the Hα λ6565 emission line, for 19 luminous (LBol = 46.5-47.5 erg s-1) Sloan Digital Sky Survey quasars, at redshifts 2 < z < 2.7, with C IV emission lines spanning the full range of blueshifts present in the population. A strong correlation between C IV velocity width and blueshift is found and, at large blueshifts, >2000 km s-1, the velocity widths appear to be dominated by non-virial motions. Black hole masses, based on the full width at half-maximum of the C IV emission line, can be overestimated by a factor of 5 at large blueshifts. A larger sample of quasar spectra with both C IV and H β, or Hα, emission lines will allow quantitative corrections to C IV-based black hole masses as a function of blueshift to be derived. We find that quasars with large C IV blueshifts possess high Eddington luminosity ratios and that the fraction of high-blueshift quasars in a flux-limited sample is enhanced by a factor of approximately 4 relative to a sample limited by black hole mass.

  14. PROBING INTERMEDIATE-MASS BLACK HOLES WITH OPTICAL EMISSION LINES FROM TIDALLY DISRUPTED WHITE DWARFS

    SciTech Connect

    Clausen, Drew; Eracleous, Michael

    2011-01-01

    We calculate the emission-line spectrum produced by the debris released when a white dwarf (WD) is tidally disrupted by an intermediate-mass black hole (IMBH; M {approx} 10{sup 2}-10{sup 5} M{sub sun}) and we explore the possibility of using the emission lines to identify such events and constrain the properties of the IMBH. To this end, we adopt and adapt the techniques developed by Strubbe and Quataert to study the optical emission lines produced when a main-sequence star is tidally disrupted by a supermassive black hole (BH). WDs are tidally disrupted outside of the event horizon of a <10{sup 5} M{sub sun} BH, which makes these tidal disruption events good signposts of IMBHs. We focus on the optical and UV emission lines produced when the accretion flare photoionizes the stream of debris that remains unbound during the disruption. We find that the spectrum is dominated by lines due to ions of C and O, the strongest of which are C IV {lambda}1549 at early times and [O III] {lambda}5007 at later times. Furthermore, we model the profile of the emission lines in the [O III] {lambda}{lambda}4959, 5007 doublet and find that it is highly asymmetric with velocity widths of up to {approx}2500 km s{sup -1}, depending on the properties of the WD-IMBH system and the orientation of the observer. Finally, we compare the models with observations of X-ray flares and optical emission lines in the cores of globular clusters and propose how future observations can test if these features are due to a WD that has been tidally disrupted by an IMBH.

  15. ALMA capabilities for observations of spectral line emission

    NASA Astrophysics Data System (ADS)

    Wootten, Alwyn

    2008-01-01

    The Atacama Large Millimeter/submillimeter Array (ALMA) (The Enhanced Atacama Large Millimeter/submillimeter Array (known as ALMA) is an international astronomy facility. ALMA is a partnership between North America, Europe, and Japan/Taiwan, in cooperation with the Republic of Chile, and is funded in Europe by the European Southern Observatory (ESO) and Spain, in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC), and in Japan by the National Institutes of Natural Sciences (NINS) in cooperation with the Academia Sinica in Taiwan. ALMA construction and operations are led on behalf of Japan/Taiwan by the National Astronomical Observatory of Japan (NAOJ), on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI), and on behalf of Europe by ESO) combines large collecting area and location on a high dry site to provide it with unparalleled potential for sensitive millimeter/submillimeter spectral line observations. Its wide frequency coverage, superb receivers and flexible spectrometer will ensure that its potential is met. Since the 1999 meeting on ALMA Science (Wootten, ASP Conf. Ser. 235, 2001), the ALMA team has substantially enhanced its capability for line observations. ALMA’s sensitivity increased when Japan joined the project, bringing the 16 antennas of the Atacama Compcat Array (ACA), equivalent to eight additional 12 m telescopes. The first four receiver cartridges for the baseline ALMA (Japan’s entry has brought two additional bands to ALMA’s receiver retinue) have been accepted, with performance above the already-challenging specifications. ALMA’s flexibility has increased with the enhancement of the baseline correlator with additional channels and flexibility, and with the addition of a separate correlator for the ACA. As an example of the increased flexibility, ALMA is now capable of multi

  16. Ultrafast laser produced zinc plasma: Stark broadening of emission lines in nitrogen ambient

    SciTech Connect

    Rao, Kavya H.; Smijesh, N.; Nivas, Jijil JJ; Philip, Reji

    2016-04-15

    The effect of ambient pressure on Stark broadening of emission lines from neutrals and ions in an ultrafast laser (100 fs, 800 nm) produced zinc plasma is investigated. Measured spectra reveal that the full width at half maximum (δλ) of neutral lines remains unchanged in the pressure range of 10{sup −6} to 10{sup −1 }Torr, shows an even fluctuation in the pressure range of 0.1 to 100 Torr, and then increases with pressure. On the other hand, δλ of ion lines is nearly a constant from 10{sup −6} to 10{sup −3 }Torr, and then increases consistently with ambient pressure. A line narrowing of neutral emissions observed in the region of 1 to 100 Torr can be attributed to larger plasma temperatures, whereas the consistent increase in δλ with pressure seen for ion emission results from the prevalence of additional broadening mechanisms related to Coulomb interactions, ion-ion interaction, and Debye shielding. An accurate knowledge of emission line width is crucial for unambiguously calculating number density values for any given ambient pressure. Moreover, it can be relevant for the design of narrow line width, bright plasma sources for various applications.

  17. Mid Infrared Hydrogen Recombination Line Emission from the Maser Star MWC 349A

    NASA Technical Reports Server (NTRS)

    Smith, Howard A.; Strelnitski, V.; Miles, J. W.; Kelly, D. M.; Lacy, J. H.

    1997-01-01

    We have detected and spectrally resolved the mid-IR hydrogen recombination lines H6(alpha)(12.372 micrometers), H7(alpha)(19.062 micrometers), H7(beta)(l1.309 micrometers) and H8(gamma)(12.385 micrometers) from the star MWC349A. This object has strong hydrogen maser emission (reported in the millimeter and submillimeter hydrogen recombination lines from H36(alpha) to H21(alpha)) and laser emission (reported in the H15(alpha), H12(alpha) and H10(alpha) lines). The lasers/masers are thought to arise predominantly in a Keplerian disk around the star. The mid-IR lines do not show evident signs of lasing, and can be well modeled as arising from the strong stellar wind, with a component arising from a quasi-static atmosphere around the disk, similar to what is hypothesized for the near IR (less than or equal to 4 micrometers) recombination lines. Since populations inversions in the levels producing these mid-IR transitions are expected at densities up to approximately 10(exp 11)/cu cm, these results imply either that the disk does not contain high-density ionized gas over long enough path lengths to produce a gain approximately 1, and/or that any laser emission from such regions is small compared to the spontaneous background emission from the rest of the source as observed with a large beam. The results reinforce the interpretation of the far-IR lines as true lasers.

  18. Near-infrared emission-line and continuum observations from the 1991 eclipse

    NASA Astrophysics Data System (ADS)

    Penn, M. J.; Arnaud, J.; Mickey, D. L.; Labonte, B. J.

    1994-11-01

    We report observations made during the 1991 July 11 total solar eclipse from the University of Hawaii 61 cm south telescope on the summit of Mauna Kea, Hawaii. The eclipse observations entail CCD imaging of a coronal region on the southeast limb of the Sun using four wavelength channels isolated with narrowband interference filters. We obtain two long exposure images in each channel including the continuum (lambda = 10690 A), the two near-infrared (Fe XIII) emission lines (lambda = 10747, 10798 A), and the He I line (lambda = 10830 A). We calibrate the images to the center-of-disk solar intensity. The (Fe XIII) images are the first coronal images published from these emission lines. We find significant structural differences between the line and continuum images implying large temperature gradients in our small field of view. We compute the line ratio of the two (Fe XIII) emission lines (R) and find that the ratio is within the limits 1.2 greater than or = R greater than or = 15.0. We examine the motion seen in the prominence structure and find transverse velocities of up to about 30 km/s. Finally we see no cold coronal emission to a limit of 2 x 10-7 solar BETA.

  19. A First-Principles Spectral Model for Blazar Jet Acceleration and Emission with Klein-Nishina Scattering of Multiple Broad Line Region Emission Lines

    NASA Astrophysics Data System (ADS)

    Lewis, Tiffany R.; Finke, Justin; Becker, Peter A.

    2017-08-01

    Blazars are a sub-class of active galactic nuclei, with a polar jet aligned along our line of sight. Emission from blazar jets is observed across the electromagnetic spectrum. In our model we assume that the emission emanates from one homogeneous zone in the jet, which is in the process of passing through the Broad Line Region (BLR). We start from first-principles to build up a particle transport model, whose solution is the electron distribution, rather than assuming a convenient functional form. Our transport model considers shock acceleration, adiabatic expansion, stochastic acceleration, Bohm diffusion, synchrotron radiation, and Klein-Nishina radiation pulling seed photons from the BLR and dusty torus. We obtain the steady-state electron distribution computationally, and calculate individual spectral contributions due to synchrotron with self-absorption, disk, synchrotron self-Compton, and external-Compton emission, using numerical integration. We compare the resulting radiation spectrum with multi-wavelength data for 3C 279, during quiescence and two flares. Our preliminary results suggest that the jet emission is produced in a region with a sub-equipartition magnetic field, and that the magnetic field in the jet decreases during flaring events, implying that reconnection may play a role in blazar flares.

  20. Radiative transfer of emission lines with non-Maxwellian velocity distribution function: Application to Mercury D2 sodium lines

    NASA Astrophysics Data System (ADS)

    Chaufray, J.-Y.; Leblanc, F.

    2013-04-01

    We describe the theory and the numerical model used to simulate Doppler-broadened resonant emission lines for any type of velocity function distribution. The field of application of this theoretical model of radiative transfer is particularly well suited for the study of weakly dense atmospheres which are far from local thermodynamic equilibrium (as is the case for most planetary upper atmospheres/exospheres). This model is applied to study the potential effects of radiative transfer and non-Maxwellian distributions on the spectral shape of the D2 sodium emission line in Mercury's exosphere. The small (but not negligible) optical thickness of the D2 sodium emission of an exosphere like Mercury's (with a peak optical thickness of ˜2) can result in an increase of the observed spectral width by up to a few tens of percent. Combined with the non-Maxwellian nature of the exospheric velocity distribution, it may lead to an increase in the spectral width by a factor of up to 2 with respect to the width of an optically thin emission and a Maxwellian distribution. This model has been used to analyze new THEMIS observations of Mercury's exosphere obtained at very high spectral resolution in a companion paper (Leblanc, F., Chaufray, J.-Y., Doressoundiram, A., Berthelier, J.-J., Mangano, V., Lopez-Ariste, A., Borin, P. [2013]).

  1. Lyα emission-line reconstruction for high-z QSOs

    NASA Astrophysics Data System (ADS)

    Greig, Bradley; Mesinger, Andrei; McGreer, Ian D.; Gallerani, Simona; Haiman, Zoltán

    2017-04-01

    We introduce an intrinsic Lyα emission-line profile reconstruction method for high-z quasars (QSOs). This approach utilises a covariance matrix of emission-line properties obtained from a large, moderate-z (2 ≤ z ≤ 2.5), high signal to noise (S/N > 15) sample of BOSS QSOs. For each QSO, we complete a Monte Carlo Markov Chain fitting of the continuum and emission-line properties and perform a visual quality assessment to construct a large data base of robustly fit spectra. With this data set, we construct a covariance matrix to describe the correlations between the high-ionization emission lines Lyα, C IV, Si IV +O IV] and C III], and find it to be well approximated by an N-dimensional Gaussian distribution. This covariance matrix characterizes the correlations between the linewidth, peak height and velocity offset from systemic while also allowing for the existence of broad- and narrow-line components for Lyα and C IV. We illustrate how this covariance matrix allows us to statistically characterize the intrinsic Lyα line solely from the observed spectrum redward of 1275 Å. This procedure can be used to reconstruct the intrinsic Lyα line emission profile in cases where Lyα may otherwise be obscured. Applying this reconstruction method to our sample of QSOs, we recovered the Lyα line flux to within 15 per cent of the measured flux at 1205 Å (1220 Å) ∼85 (90) per cent of the time.

  2. Double-peaked Emission Lines Due to a Radio Outflow in KISSR 1219

    NASA Astrophysics Data System (ADS)

    Kharb, P.; Subramanian, S.; Vaddi, S.; Das, M.; Paragi, Z.

    2017-09-01

    We present the results from 1.5 and 5 GHz phase-referenced VLBA and 1.5 GHz Karl G. Jansky Very Large Array (VLA) observations of the Seyfert 2 galaxy KISSR 1219, which exhibits double-peaked emission lines in its optical spectrum. The VLA and VLBA data reveal a one-sided core-jet structure at roughly the same position angles, providing evidence of an active galactic nucleus outflow. The absence of dual parsec-scale radio cores puts the binary black-hole picture in doubt for the case of KISSR 1219. The high brightness temperatures of the parsec-scale core and jet components (>106 K) are consistent with this interpretation. Doppler boosting with jet speeds of ≳0.55c to ≳0.25c, going from parsec to kiloparsec scales, at a jet inclination ≳50° can explain the jet one-sidedness in this Seyfert 2 galaxy. A blueshifted broad emission line component in [O iii] is also indicative of an outflow in the emission line gas at a velocity of ∼350 km s‑1, while the [O i] doublet lines suggest the presence of shock-heated gas. A detailed line ratio study using the MAPPINGS III code further suggests that a shock+precursor model can explain the line ionization data well. Overall, our data suggest that the radio outflow in KISSR 1219 is pushing the emission line clouds, both ahead of the jet and in a lateral direction, giving rise to the double peak emission line spectra.

  3. X-ray Emission Line Anisotropy Effects on the Isoelectronic Temperature Measurement Method

    NASA Astrophysics Data System (ADS)

    Liedahl, Duane; Barrios, Maria; Brown, Greg; Foord, Mark; Gray, William; Hansen, Stephanie; Heeter, Robert; Jarrott, Leonard; Mauche, Christopher; Moody, John; Schneider, Marilyn; Widmann, Klaus

    2016-10-01

    Measurements of the ratio of analogous emission lines from isoelectronic ions of two elements form the basis of the isoelectronic method of inferring electron temperatures in laser-produced plasmas, with the expectation that atomic modeling errors cancel to first order. Helium-like ions are a common choice in many experiments. Obtaining sufficiently bright signals often requires sample sizes with non-trivial line optical depths. For lines with small destruction probabilities per scatter, such as the 1s2p-1s2 He-like resonance line, repeated scattering can cause a marked angular dependence in the escaping radiation. Isoelectronic lines from near-Z equimolar dopants have similar optical depths and similar angular variations, which leads to a near angular-invariance for their line ratios. Using Monte Carlo simulations, we show that possible ambiguities associated with anisotropy in deriving electron temperatures from X-ray line ratios are minimized by exploiting this isoelectronic invariance.

  4. An Analytic Inversion of Emission Lines of Arbitrary Optical Depth for the Structure of Supernova Ejecta

    NASA Astrophysics Data System (ADS)

    Ignace, R.; Hendry, M. A.

    2000-05-01

    We have derived a method for inverting emission line profiles formed in supernova ejecta. The derivation assumes spherical symmetry and homologous expansion (i.e., v(r) r). The inversion is analytic and even takes account of occultation by a pseudo-photosphere. Previous inversion methods have been developed which are restricted to optically thin lines, but the particular case of homologous expansion permits an analytic inversion for lines of arbitrary optical depth. In fact, we show that the quantity that is generically retrieved is the run of line intensity Iλ with radius in the ejecta shell. This result could be applied to resonance lines, recombination lines, or lines dominated by collisional de-excitation.

  5. Broad emission lines variability: a window into the heart of AGN

    NASA Astrophysics Data System (ADS)

    Ilic, Dragana; Popovic, Luka C.; Shapovalova, Alla I.; Afanasiev, V. L.; Chavushyan, V. H.; Burenkov, A.; Kollatschny, W.; Kovacevic, A.

    2016-08-01

    The broad emission lines of active galactic nuclei (AGN) are known to vary both in flux and shape, and are often showing very complex line profiles. They can give us invaluable information about the kinematics and geometry of the broad line region (BLR) where these lines are originating from. The BLR is close to the supermassive black hole in AGN and may hold basic information about the formation and fueling of AGN.Here we summarize the results of the line and continuum variability of a sample of broad line AGN, obtained with the long-term optical monitoring campaign performed with telescopes of SAO (Russia), OAGH and OAN-SPM (Mexico), and Calar Alto (Spain). We monitored different type of broad line AGN (double-peaked, radio loud and radio quiet, NLSy1 and a supermassive binary black hole candidate) which show different variability characteristics that can be explained by different physical properties in BLR.

  6. The Far-Infrared Emission Line and Continuum Spectrum of the Seyfert Galaxy NGC 1068

    NASA Technical Reports Server (NTRS)

    Spinoglio, Luigi; Smith, Howard A.; Gonzalez-Alfonso, Eduardo; Fisher, Jacqueline

    2005-01-01

    We report on the analysis of the first complete far-infrared spectrum (43-197 microns) of the Seyfert 2 galaxy NGC 1068 as observed with the Long Wavelength Spectrometer (LWS) onboard the Infrared Space Observatory (ISO). In addition to the 7 expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163 microns were all detected in emission, which is unique among galaxies with full LWS spectra, where the 119 micron line, where detected, is always in absorption. The observed line intensities were modelled together with IS0 Short Wavelength Spectrometer (SWS) and optical and ultraviolet line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of approximately 3kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on the instantaneous starburst age of 5 Myr constrained by the Br gamma equivalent width in the starburst ring, and starburst synthesis models of the mid- and far-infrared fine-structure line emission, a low ionization parameter (U=10(exp -3.5)) and low densities (n=100 cm (exp -3)) are derived. Combining the AGN and starburst components, we succeed in modeling the overall UV to far-IR atomic spectrum of SGC 1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.4. The OH 119 micron emission indicates that the line is collisionally excited, and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance

  7. RELATIVISTIC BROADENING OF IRON EMISSION LINES IN A SAMPLE OF ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Brenneman, Laura W.; Reynolds, Christopher S.

    2009-09-10

    We present a uniform X-ray spectral analysis of eight type-1 active galactic nuclei that have been previously observed with relativistically broadened iron emission lines. Utilizing data from the XMM-Newton European Photon Imaging Camera (EPIC-pn) we carefully model the spectral continuum, taking complex intrinsic absorption and emission into account. We then proceed to model the broad Fe K{alpha} feature in each source with two different accretion disk emission line codes, as well as a self-consistent, ionized accretion disk spectrum convolved with relativistic smearing from the inner disk. Comparing the results, we show that relativistic blurring of the disk emission is required to explain the spectrum in most sources, even when one models the full reflection spectrum from the photoionized disk.

  8. Economical Emission-Line Mapping: ISM Properties of Nearby Protogalaxy Analogs

    NASA Astrophysics Data System (ADS)

    Monkiewicz, Jacqueline A.

    2017-01-01

    Optical emission line imaging can produce a wealth of information about the conditions of the interstellar medium, but a full set of custom emission-line filters for a professional-grade telescope camera can cost many thousands of dollars. A cheaper alternative is to use commercially-produced 2-inch narrow-band astrophotography filters. In order to use these standardized filters with professional-grade telescope cameras, custom filter mounts must be manufactured for each individual filter wheel. These custom filter adaptors are produced by 3-D printing rather than standard machining, which further lowers the total cost.I demonstrate the feasibility of this technique with H-alpha, H-beta, and [OIII] emission line mapping of the low metallicity star-forming galaxies IC10 and NGC 1569, taken with my astrophotography filter set on three different 2-meter class telescopes in Southern Arizona.

  9. Spectroscopic Properties of Selected Narrow Emission Line Galaxies from the COSMOS Field

    NASA Astrophysics Data System (ADS)

    Colon, Amy M.; Carroll, P.; Roberts, R.; Wong, N.; Liu, C.

    2007-12-01

    We present properties of seven blue narrow emission line galaxies (NELGs) in the redshift range 0.25 < z < 0.73, initially selected as QSO candidates in the COSMOS 2-degree survey field. These galaxies have been selected for the high signal-to-noise of their spectra, as indicated by the presence of the emission line [NeIII] 3869 Angstroms. Emission line diagnostics are used to measure metallicities and star formation rates, and to test the presence of AGN. Hubble ACS images are used to measure their surface brightness distributions and quantitative morphologies. Preliminary results indicate that these objects are forming stars at a rate of 4 to 20 solar masses per year; and their metallicity appears not to vary with the galaxy's concentration index which ranges 0.42 to 0.63.

  10. Comparison of Fe XVIII and Fe XIX Line Emissions with Spectral Models

    NASA Astrophysics Data System (ADS)

    Desai, P.; Brickhouse, N. S.; Drake, J. J.; Edgar, R. J.; Hoogerwerf, R.; Kashyap, V.; Wargelin, B. J.; Smith, R. K.; Huenemoerder, D. P.; Liedahl, D. A.

    2005-06-01

    We discuss here the observations of Fe XVIII and XIX emission lines and compare the X-ray, EUV and FUV lines with the spectral codes widely used today (e.g. FAC and APEC). We assess the relative accuracy of these spectral models and try to identify the critical atomic data and processes. Capella with a narrow enhancement in its emission measure distribution at 6 MK provides a unique opportunity to test the Fe XVIII and Fe XIX model emissivities which peak from 6 to 8 MK. We use the summed spectra from Chandra HETG/ACIS-S and LETG/HRC-S, as well as contemporaneous EUVE and FUSE observations, to measure line ratios for comparison with predictions.

  11. An optical emission-line phase of the extreme carbon star IRC +30219

    NASA Technical Reports Server (NTRS)

    Cohen, M.

    1980-01-01

    Optical spectroscopic monitoring of the extreme carbon star IRC +30219 has revealed striking changes between 1977 and 1980. The stellar photosphere was barely visible in early 1979. There was an emission line spectrum consisting of H, forbidden O I, forbidden O II, forbidden N I, forbidden N II, forbidden S II, and He I. It is likely that these lines arose in a shocked region where recent stellar mass loss encountered the extensive circumstellar envelope. By late 1979, this emission-line spectrum had vanished, and the photosphere had reappeared. The weakening of the photospheric features in early 1979 was caused by increased attenuation of starlight and overlying thermal emission, both due to recently condensed hot dust grains.

  12. 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.

  13. The asymmetric profile of the H76 alpha line emission from MWC349

    NASA Technical Reports Server (NTRS)

    Rodriquez, L. F.; Canto, J.; Escalante, V.; Moran, J. M.

    1986-01-01

    MWC349 is an emission-line star found by Merrill, Humason and Burwell (1932). Braes, Habing and Schoenmaker (1972) discovered that it is a strong radio source. The radio emission originates in a massive ionized wind that is expanding with a velocity of about 50 km s(-1). Its continuum spectrum fits well a nu(0.6) power law from the cm wavelengths to the far-IR. Radio recombination line emission from the envelope of MWC349 was first detected by Altenhoff, Strittmatter and Wendker (1981). We have obtained good signal-to-noise ratio, Very Large Array observations of the H76 alpha radio recombination line from the ionized wind of MWC349. Our data reveal that the profile is markedly asymmetric, with a steep rise on the blue side. This asymmetry could be due to non-LTE effects in the formation and transfer of the line or to intrinsic asymmetries in the envelope. Our analysis suggests that most probably the peculiar profile is caused by a non-LTE enhancement of the line emission from the side of the envelope nearer to the observer. This asymmetry has the opposite sense than that observed in optical and IR recombination lines, where a different effect (absorption of the stellar continuum by the gas in the wind between the star and the observer) is known to be dominant, leading to the classic P Cygni profile. We propose that the profiles of the radio recombination lines from ionized stellar winds will have this characteristic shape, while optical and IR recombination lines are characterized by P Cygni-like profiles. Unfortunately, at present the detection of radio recombination lines from ionized stellar winds is only feasible for MWC349 and a few other objects.

  14. Unraveling the contribution of jets and discs to far-infrared line emission

    NASA Astrophysics Data System (ADS)

    Alonso-Martínez, M.; Riviere-Marichalar, P.; Meeus, G.; Kamp, I.; Fang, M.; Podio, L.; Dent, W. R. F.; Eiroa, C.

    2017-03-01

    As part of Herschel's key programme ”Gas in Protoplanetary Systems” (GASPS), we have analyzed far-IR (60–190 μm) spectra of protoplanetary discs around 76 T Tauri stars locatedin Taurus in different evolutionary states (Class I down to Class III), 27 show jet/outflow activity. We derived fluxes of all detected atomic and molecular lines - [OI], [CII], CO, H_2O and OH - to produce a complete and consistent FIR lines catalogue. Outflow sources are found to have the richest spectra and highest line fluxes, while non-outflow sources are rather poor in lines. We find correlations between several emission lines which suggests a common origin. To verify whether the line emission is associated with the protoplanetary disc or shocks, we compared the observed line fluxes and their ratios with disc and shock models. We find that just from an observational perspective, the outflow rather than the disc dominates the emission at early evolutionary stages (Class I/II).

  15. The Sloan Digital Sky Survey Reverberation Mapping Project: Velocity Shifts of Quasar Emission Lines

    NASA Astrophysics Data System (ADS)

    Shen, Yue; Brandt, W. N.; Richards, Gordon T.; Denney, Kelly D.; Greene, Jenny E.; Grier, C. J.; Ho, Luis C.; Peterson, Bradley M.; Petitjean, Patrick; Schneider, Donald P.; Tao, Charling; Trump, Jonathan R.

    2016-11-01

    Quasar emission lines are often shifted from the systemic velocity due to various dynamical and radiative processes in the line-emitting region. The level of these velocity shifts depends both on the line species and on quasar properties. We study velocity shifts for the line peaks (not the centroids) of various narrow and broad quasar emission lines relative to systemic using a sample of 849 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. The coadded (from 32 epochs) spectra of individual quasars have sufficient signal-to-noise ratio (S/N) to measure stellar absorption lines to provide reliable systemic velocity estimates, as well as weak narrow emission lines. The large dynamic range in quasar luminosity (∼2 dex) of the sample allowed us to explore potential luminosity dependence of the velocity shifts. We derive average line peak velocity shifts as a function of quasar luminosity for different lines, and quantify their intrinsic scatter. We further quantify how well the peak velocity can be measured as a function of continuum S/N, and demonstrate that there is no systematic bias in the velocity measurements when S/N is degraded to as low as ∼3 per SDSS pixel (∼ 69 {km} {{{s}}}-1). Based on the observed line shifts, we provide empirical guidelines on redshift estimation from [O ii] λ 3727, [O iii] λ 5007, [Ne v] λ 3426, Mg ii, C iii], He ii λ 1640, broad Hβ, C iv, and Si iv, which are calibrated to provide unbiased systemic redshifts in the mean, but with increasing intrinsic uncertainties of 46, 56, 119, 205, 233, 242, 400, 415, and 477 {km} {{{s}}}-1, in addition to the measurement uncertainties. These results demonstrate the infeasibility of measuring quasar redshifts to better than ∼ 200 {km} {{{s}}}-1 with only broad lines.

  16. THE CONNECTIONS BETWEEN THE UV AND OPTICAL Fe ii EMISSION LINES IN TYPE 1 AGNs

    SciTech Connect

    Kovacević-Dojcinović, Jelena; Popović, Luka Č. E-mail: lpopovic@aob.bg.ac.rs

    2015-12-15

    We investigate the spectral properties of the UV (λλ2650–3050 Å) and optical (λλ4000–5500 Å) Fe ii emission features in a sample of 293 Type 1 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey database. We explore different correlations between their emission line properties, as well as the correlations with other emission lines from the spectral range. We find several interesting correlations and outline the most interesting results as follows. (i) There is a kinematical connection between the UV and optical Fe ii lines, indicating that the UV and optical Fe ii lines originate from the outer part of the broad line region, the so-called intermediate line region. (ii) The unexplained anticorrelations of the optical Fe ii equivalent width (EW Fe ii{sub opt}) versus EW [O iii] 5007 Å and EW Fe ii{sub opt} versus FWHM Hβ have not been detected for the UV Fe ii lines. (iii) The significant averaged redshift in the UV Fe ii lines, which is not present in optical Fe ii, indicates an inflow in the UV Fe ii emitting clouds, and probably their asymmetric distribution. (iv) Also, we confirm the anticorrelation between the intensity ratio of the optical and UV Fe ii lines and the FWHM of Hβ, and we find the anticorrelations of this ratio with the widths of Mg ii 2800 Å, optical Fe ii, and UV Fe ii. This indicates a very important role for the column density and microturbulence in the emitting gas. We discuss the starburst activity in high-density regions of young AGNs as a possible explanation of the detected optical Fe ii correlations and intensity line ratios of the UV and optical Fe ii lines.

  17. B Stars with and without emission lines, parts 1 and 2

    NASA Technical Reports Server (NTRS)

    Underhill, A. (Editor); Doazan, V. (Editor)

    1982-01-01

    The spectra for B stars for which emission lines occur not on the main sequence, but only among the supergiants, and those B stars for which the presence of emission in H ahlpa is considered to be a significant factor in delineating atmospheric structure are examined. The development of models that are compatible with all known facts about a star and with the laws of physics is also discussed.

  18. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1975-01-01

    Strong 10 micrometer line emission from (C-12)(O-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features.

  19. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1976-01-01

    Strong 10-micron line emission from (C-12)(O-16)2 in the upper atmosphere of Venus has been detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicated mean zonal wind velocities less than 10 m/s in the upper atmosphere near the equator. No evidence was found for the 100-m/s wind velocity implied by the apparent four-day rotation period of ultraviolet cloud features.

  20. Heterodyne detection of CO2 emission lines and wind velocities in the atmosphere of Venus

    NASA Technical Reports Server (NTRS)

    Betz, A. L.; Johnson, M. A.; Mclaren, R. A.; Sutton, E. C.

    1975-01-01

    Strong 10 micrometer line emission from (c-12)(o-16)2 in the upper atmosphere of Venus was detected by heterodyne techniques. Observations of the absolute Doppler shift of the emission features indicate mean zonal wind velocities less than 10 m/sec in the upper atmosphere near the equator. No evidence was found of the 100 m/sec wind velocity implied by the apparent 4-day rotation period of ultraviolet cloud features.

  1. Composition of an emission line system in black hole host globular cluster RZ2109

    SciTech Connect

    Steele, Matthew M.; Zepf, Stephen E.; Maccarone, Thomas J.; Kundu, Arunav; Rhode, Katherine L.; Salzer, John J.

    2014-04-20

    We present an analysis of optical spectra from the globular cluster RZ2109 in NGC 4472, which hosts the first unambiguous globular cluster black hole. We use these spectra to determine the elemental composition of the emission line system associated with this source, and to constrain the age and metallicity of the host globular cluster. For the emission line system of RZ2109, our analysis indicates the [O III] λ5007 equivalent width is 33.82 ± 0.39 Å and the Hβ equivalent width is 0.32 ± 0.32 Å, producing a formal [O III] λ5007/Hβ emission line ratio of 106 for a 3200 km s{sup –1} measurement aperture covering the full velocity width of the [O III] λ5007 line. Within a narrower 600 km s{sup –1} aperture covering the highest luminosity velocity structure in the line complex, we find [O III] λ5007/Hβ = 62. The measured [O III] λ5007/Hβ ratios are significantly higher than can be produced in radiative models of the emission line region with solar composition, and the confidence interval limits exclude all but models which have gas masses much larger than those for a single star. Therefore, we conclude that the region from which the [O III] λ5007 emission originates is hydrogen-depleted relative to solar composition gas. This finding is consistent with emission from an accretion-powered outflow driven by a hydrogen-depleted donor star, such as a white dwarf, being accreted onto a black hole.

  2. (12)CO (3-2) & (1-0) emission line observations of nearby starburst galaxy nuclei

    NASA Technical Reports Server (NTRS)

    Devereux, Nicholas; Taniguchi, Yoshiaki; Sanders, D. B.; Nakai, N.; Young, J. S.

    1994-01-01

    New measurements of the (12)CO (1-0) and (12)CO (3-2) line emission are presented for the nuclei of seven nearby starburst galaxies selected from a complete sample of 21 nearby starburst galaxies for which the nuclear star formation rates are measured to be comparable to the archetype starburst galaxies M82 and NGC 253. The new observations capitalize on the coincidence between the beam size of the 45 m Nobeyama telescope at 115 GHz and that of the 15 m James Clerk Maxwell Telescope at 345 GHz to measure the value of the (12)CO (3-2)/(1-0) emission line ratio in a 15 sec (less than or equal to 2.5 kpc) diameter region centered on the nuclear starburst. In principle, the (12)CO (3-2)/(1-0) emission line ratio provides a measure of temperature and optical depth for the (12)CO gas. The error weighted mean value of the (12)CO (3-2)/(1-0) emission line ratio measured for the seven starburst galaxy nuclei is -0.64 +/- 0.06. The (12)CO (3-2)/(1-0) emission line ratio measured for the starburst galaxy nuclei is significantly higher than the average value measured for molecular gas in the disk of the Galaxy, implying warmer temperatures for the molecular gas in starburst galaxy nuclei. On the other hand, the (12)CO (3-2)/(1-0) emission line ratio measured for the starburst galaxy nuclei is not as high as would be expected if the molecular gas were hot, greater than 20 K, and optically thin, tau much less than 1. The total mass of molecular gas contained within the central 1.2-2.8 kpc diameter region of the starburst galaxy nuclei ranges from 10(exp 8) to 10(exp 9) solar mass. While substantial, the molecular gas mass represents only a small percentage, approximately 9%-16%, of the dynamical mass in the same region.

  3. (12)CO (3-2) & (1-0) emission line observations of nearby starburst galaxy nuclei

    NASA Technical Reports Server (NTRS)

    Devereux, Nicholas; Taniguchi, Yoshiaki; Sanders, D. B.; Nakai, N.; Young, J. S.

    1994-01-01

    New measurements of the (12)CO (1-0) and (12)CO (3-2) line emission are presented for the nuclei of seven nearby starburst galaxies selected from a complete sample of 21 nearby starburst galaxies for which the nuclear star formation rates are measured to be comparable to the archetype starburst galaxies M82 and NGC 253. The new observations capitalize on the coincidence between the beam size of the 45 m Nobeyama telescope at 115 GHz and that of the 15 m James Clerk Maxwell Telescope at 345 GHz to measure the value of the (12)CO (3-2)/(1-0) emission line ratio in a 15 sec (less than or equal to 2.5 kpc) diameter region centered on the nuclear starburst. In principle, the (12)CO (3-2)/(1-0) emission line ratio provides a measure of temperature and optical depth for the (12)CO gas. The error weighted mean value of the (12)CO (3-2)/(1-0) emission line ratio measured for the seven starburst galaxy nuclei is -0.64 +/- 0.06. The (12)CO (3-2)/(1-0) emission line ratio measured for the starburst galaxy nuclei is significantly higher than the average value measured for molecular gas in the disk of the Galaxy, implying warmer temperatures for the molecular gas in starburst galaxy nuclei. On the other hand, the (12)CO (3-2)/(1-0) emission line ratio measured for the starburst galaxy nuclei is not as high as would be expected if the molecular gas were hot, greater than 20 K, and optically thin, tau much less than 1. The total mass of molecular gas contained within the central 1.2-2.8 kpc diameter region of the starburst galaxy nuclei ranges from 10(exp 8) to 10(exp 9) solar mass. While substantial, the molecular gas mass represents only a small percentage, approximately 9%-16%, of the dynamical mass in the same region.

  4. Mg I emission lines at 12 and 18 μm in K giants

    NASA Astrophysics Data System (ADS)

    Sundqvist, J. O.; Ryde, N.; Harper, G. M.; Kruger, A.; Richter, M. J.

    2008-08-01

    Context: The solar mid-infrared metallic emission lines have already been observed and analyzed well, and the formation scenario of the Mg I 12 μm lines has been known for more than a decade. Detections of stellar emission at 12 μm have, however, been limited to Mg I in very few objects. Previous modeling attempts have been made only for Procyon and two cool evolved stars, with unsatisfactory results for the latter. This prevents the lines' long predicted usage as probes of stellar magnetic fields. Aims: We want to explain our observed Mg I emission lines at 12 μm in the K giants Pollux, Arcturus, and Aldebaran and at 18 μm in Pollux and Arcturus. We discuss our modeling of these lines and particularly how various aspects of the model atom affect the emergent line profiles. Methods: High-resolution observational spectra were obtained using TEXES at Gemini North and the IRTF. To produce synthetic line spectra, we employed standard one-dimensional, plane-parallel, non-LTE modeling for trace elements in cool stellar atmospheres. We computed model atmospheres with the MARCS code, applied a comprehensive magnesium model atom, and used the radiative transfer code MULTI to solve for the magnesium occupation numbers in statistical equilibrium. Results: The Mg I emission lines at 12 μm in the K giants are stronger than in the dwarfs observed so far. We present the first observed stellar emission lines from Mg I at 18 μm and from Al I, Si I, and presumably Ca I at 12 μm. We successfully reproduce the observed Mg I emission lines simultaneously in the giants and in the Sun, but show how the computed line profiles depend critically on atomic data input and how the inclusion of energy levels with n ≥ 10 and collisions with neutral hydrogen are necessary to obtain reasonable fits. Partly based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the

  5. Emission Line Galaxies in the STIS Parallel Survey. 1; Observations and Data Analysis

    NASA Technical Reports Server (NTRS)

    Teplitz, Harry I.; Collins, Nicholas R.; Gardner, Jonathan P.; Hill, Robert S.; Heap, Sara R.; Lindler, Don J.; Rhodes, Jason; Woodgate, Bruce E.

    2002-01-01

    In the first three years of operation STIS obtained slitless spectra of approximately 2500 fields in parallel to prime HST observations as part of the STIS Parallel Survey (SPS). The archive contains approximately 300 fields at high galactic latitude (|b| greater than 30) with spectroscopic exposure times greater than 3000 seconds. This sample contains 220 fields (excluding special regions and requiring a consistent grating angle) observed between 6 June 1997 and 21 September 2000, with a total survey area of approximately 160 square arcminutes. At this depth, the SPS detects an average of one emission line galaxy per three fields. We present the analysis of these data, and the identification of 131 low to intermediate redshift galaxies detected by optical emission lines. The sample contains 78 objects with emission lines that we infer to be redshifted [OII]3727 emission at 0.43 < z < 1.7. The comoving number density of these objects is comparable to that of Halpha-emitting galaxies in the NICMOS parallel observations. One quasar and three probable Seyfert galaxies are detected. Many of the emission-line objects show morphologies suggestive of mergers or interactions. The reduced data are available upon request from the authors.

  6. Candidate Hα emission and absorption line sources in the Galactic Bulge Survey

    NASA Astrophysics Data System (ADS)

    Wevers, T.; Jonker, P. G.; Nelemans, G.; Torres, M. A. P.; Groot, P. J.; Steeghs, D.; Maccarone, T. J.; Hynes, R. I.; Heinke, C.; Britt, C.

    2017-04-01

    We present a catalogue of candidate Hα emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (l × b) = (6° × 1°) centred at b = 1.5° above and below the Galactic Centre), covering the magnitude range 16 ≤ r΄ ≤ 22.5. We utilize (r΄ - i΄, r΄ - Hα) colour-colour diagrams to select Hα emission and absorption line candidates, and also identify blue objects (compared to field stars) using the r΄ - i΄ colour index. We identify 1337 Hα emission line candidates and 336 Hα absorption line candidates. These catalogues likely contain a plethora of sources, ranging from active (binary) stars, early-type emission line objects, cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) to background active galactic nuclei (AGN). The 389 blue objects we identify are likely systems containing a compact object, such as CVs, planetary nebulae and LMXBs. Hot subluminous dwarfs (sdO/B stars) are also expected to be found as blue outliers. Cross-matching our outliers with the GBS X-ray catalogue yields 16 sources, including 7 (magnetic) CVs and 1 qLMXB candidate among the emission line candidates and 1 background AGN for the absorption line candidates. One of the blue outliers is a high-state AM CVn system. Spectroscopic observations combined with the multiwavelength coverage of this area, including X-ray, ultraviolet and (time-resolved) optical and infrared observations, can be used to further constrain the nature of individual sources.

  7. Spectroscopic Study of the HST/ACS PEARS Emission-line Galaxies

    NASA Astrophysics Data System (ADS)

    Xia, Lifang; Malhotra, Sangeeta; Rhoads, James; Pirzkal, Norbert; Zheng, Zhenya; Meurer, Gerhardt; Straughn, Amber; Grogin, Norman; Floyd, David

    2011-02-01

    We present spectroscopy of 76 emission-line galaxies (ELGs) in Chandra Deep Field South taken with the LDSS3 spectrograph on the Magellan Telescope. These galaxies are selected because they have emission lines with the Advanced Camera for Surveys (ACS) grism data in the Hubble Space Telescope Probing Evolution and Reionization Spectroscopically (PEARS) grism Survey. The ACS grism spectra cover the wavelength range 6000-9700 Å and most PEARS grism redshifts are based on a single emission line + photometric redshifts from broadband colors; the Magellan spectra cover a wavelength range from 4000 Å to 9000 Å and provide a check on redshifts derived from PEARS data. We find an accuracy of σ z = 0.006 for the ACS grism redshifts with only one catastrophic outlier. We probe for active galactic nuclei (AGNs) in our sample via several different methods. In total, we find 7 AGNs and AGN candidates out of 76 galaxies. Two AGNs are identified from the X-ray full-band luminosity, L X-ray,FB > 1043 erg s-1, the line widths, and the power-law continuum spectra. Two unobscured faint AGN candidates are identified from the X-ray full-band luminosity L X-ray,FB ~ 1041 erg s-1, the hardness ratio and the column density, and the emission-line and X-ray derived SFRs. Two candidates are classified based on the line ratio of [N II]λ6584/Hα versus [O III]λ5007/Hβ(BPT diagram), which are between the empirical and theoretical demarcation curves, i.e., the transition region from star-forming galaxies to AGNs. One AGN candidate is identified from the high-ionization emission line He IIÅ4686.

  8. The extended narrow line region of NGC 4151. I - Emission line ratios and their implications

    NASA Astrophysics Data System (ADS)

    Penston, M. V.; Robinson, A.; Alloin, D.; Appenzeller, I.; Aretxaga, I.; Axon, D. J.; Baribaud, T.; Barthel, P.; Baum, S. A.; Boisson, C.; de Bruyn, A. G.; Clavel, J.; Colina, L.; Dennefeld, M.; Diaz, A.; Dietrich, M.; Durret, F.; Dyson, J. E.; Gondhalekar, P.; van Groningen, E.; Jablonka, P.; Jackson, N.; Kollatschny, W.; Laurikainen, E.; Lawrence, A.; Masegosa, J.; McHardy, I.; Meurs, E. J. A.; Miley, G.; Moles, M.; O'Brien, P.; O'Dea, C.; del Olmo, A.; Pedlar, A.; Perea, J.; Perez, E.; Perez-Fournon, I.; Perry, J.; Pilbratt, G.; Rees, M.; Robson, I.; Rodriguez-Pascual, P.; Rodriguez Espinosa, J. M.; Santos-Lleo, M.; Schilizzi, R.; Stasińska, G.; Stirpe, G. M.; Tadhunter, C.; Terlevich, E.; Terlevich, R.; Unger, S.; Vila-Vilaro, V.; Vilchez, J.; Wagner, S. J.; Ward, M. J.; Yates, G. J.

    1990-09-01

    The paper presents the first results from long-slit spectra of the Seyfert galaxy NGC 4151 which give average diagnostic ratios of weak lines in the Extended Narrow Line Region (ENLR) of the galaxy and the first direct density measurement in an ENLR. These data confirm that the ENLR is kinematically undisturbed gas in the disk of the galaxy which is illuminated by an ionizing continuum stronger by a factor of 13 than a power law interpolated between recently observed ultraviolet and X-ray fluxes. Explanations of this apparent excess include a hot thermal continuum, time variations, and an anisotropic rotation field.

  9. H2 line emission in three Seyfert nuclei: Evidence against UV-excitation

    NASA Technical Reports Server (NTRS)

    Geballe, T. R.

    1990-01-01

    Line emission from vibrationally excited molecular hydrogen has been detected in a considerable number of active galactic nuclei (AGNs), including those generally believed to contain compact and luminous central engines (e.g., Seyfert nuclei) and those in which the luminosity is believed to arise from massive bursts of star formation (starburst nuclei). In most of these AGNs, only the bright 1-0 S(1) line (rest wavelength 2.12 microns) has been searched for and detected to date. Line-emitting H2 can be excited directly either by energetic collisions created by shock waves or by absorption of UV radiation. Each of these excitation mechanisms has been clearly identified in galactic and extragalactic regions. In active galactic nuclei strong sources of UV and (in some case) x rays are present. If the nuclear molecular matter is quiescent (i.e., isolated from the active nucleus and not set into motion by episodes of star formation) the H2 line emission will be dominated by fluorescence, or possibly by thermal emission due to heating by x rays (Krolik, this conference). However, it is expected or indeed observed that a significant fraction of the interstellar medium in and near these nuclei is undergoing rapid motions; either generated by the central engine or by a nuclear starburst, which are capable of producing strong shock phenomena in nearby molecular gas. Thus, a priori it is not obvious which mechanism is responsible for the H2 line emission from the nucleus of an active galaxy.

  10. Emission lines in the atmosphere of the irradiated brown dwarf WD0137-349B

    NASA Astrophysics Data System (ADS)

    Longstaff, E. S.; Casewell, S. L.; Wynn, G. A.; Maxted, P. F. L.; Helling, Ch.

    2017-10-01

    We present new optical and near-infrared spectra of WD0137-349; a close white dwarf-brown dwarf non-interacting binary system with a period of ≈114 min. We have confirmed the presence of H α emission and discovered He, Na, Mg, Si, K, Ca, Ti and Fe emission lines originating from the brown-dwarf atmosphere. This is the first brown-dwarf atmosphere to have been observed to exhibit metal emission lines as a direct result of intense irradiation. The equivalent widths of many of these lines show a significant difference between the day-side and night-side of the brown dwarf. This is likely an indication that efficient heat redistribution may not be happening on this object, in agreement with models of hot Jupiter atmospheres. The H α line strength variation shows a strong phase dependency as does the width. We have simulated the Ca II emission lines using a model that includes the brown-dwarf Roche geometry and limb darkening, and we estimate the mass ratio of the system to be 0.135 ± 0.004. We also apply a gas-phase equilibrium code using a prescribed drift-phoenix model to examine how the chemical composition of the brown-dwarf upper atmosphere would change given an outward temperature increase, and discuss the possibility that this would induce a chromosphere above the brown-dwarf atmosphere.

  11. Emission lines from tidally disrupted white dwarfs and other evolved stars

    NASA Astrophysics Data System (ADS)

    Clausen, D.; Eracleous, M.; Sigurdsson, S.; Irwin, J. A.

    2012-12-01

    When a black hole tidally disrupts a star, accretion of the debris will produce a luminous flare and reveal the presence of a dormant black hole. The accretion flare can also photoionize a portion of the post-disruption debris. We present models of the emission line spectrum produced in the debris released when a white dwarf or a horizontal branch star is tidally disrupted by an intermediate-mass black hole, and discuss the possibility of using the emission lines to identify such events and constrain the properties of the black hole. We also compare the white dwarf disruption models with observations of white dwarf tidal disruption candidates in globular clusters associated with NGC 4472 and NGC 1399. The bright [O III] lines observed in each system are consistent with these models, but there are some drawbacks to interpreting these sources as tidally disrupted white dwarfs. On the other hand, models of the emission line spectrum produced when a horizontal branch star is disrupted by a ˜ 100 Mʘ black hole are in good agreement with the source in the NGC 1399 globular cluster. Finally, we describe light curves for the emission lines produced in the debris of a tidally disrupted helium core. The modeled light curves are consistent with the recent observations of Gezari et al. (2012).

  12. Emission-Line Taxonomy and the Nature of AGN-Looking Galaxies in the SDSS

    NASA Astrophysics Data System (ADS)

    Cid Fernandes, Roberto; Stasińska, Grażyna; Vale Asari, Natalia; Mateus, Abílio; Schlickmann, Marielli S.; Schoenell, William; Schoenell

    2010-05-01

    Massive spectroscopic surveys like the SDSS have revolutionized the way we study AGN and their relations to the galaxies they live in. A first step in any such study is to define samples of different types of AGN on the basis of emission-line ratios. This deceivingly simple step involves decisions on which classification scheme to use and data quality censorship. Galaxies with weak emission lines are often left aside or dealt with separetely because one cannot fully classify them onto the standard star-forming, Seyfert, or LINER categories. This contribution summarizes alternative classification schemes which include this very numerous population. We then study how star-formation histories and physical properties of the hosts vary from class to class, and present compelling evidence that the emission lines in the majority of LINER-like systems in the SDSS are not powered by black-hole accretion. The data are fully consistent with them being galaxies whose old stars provide all the ionizing power needed to explain their line ratios and luminosities. Such retired galaxies deserve a place in the emission-line taxonomy.

  13. Active galactic nuclei mergers and outflows: Observations from optical and ultraviolet emission lines

    NASA Astrophysics Data System (ADS)

    Barorws, Robert Scott

    I have investigated the nature of a subset of active galactic nuclei (AGN) which show double peaks in their characteristic optical and ultraviolet emission lines. I have performed this investigation through studies of the broad emission line regions (BLRs), which are produced less than 1 pc from the central supermassive black hole (SMBH), and the narrow emission line regions (NLRs), which originate at larger (kpc) distances. The BLR studies consist of detailed line modeling of two individual quasars with double-peaked broad emission line profiles. The modeling suggests there are two primary interpretations of the complex broad line profiles. The first possiblity is line emission from the surface of an asymmetric and/or non-uniform accretion disk of a low-accretion rate AGN; these sources are known as double-peaked emitters and account for only about 3% of the quasar population. The second possibility is line emission from the BLRs of two actively accreting SMBHs in a close (<1 pc) binary system. Such binaries are an inevitable outcome following the merger of two galaxies. The NLR studies consist of three separate projects. The first is an analysis of a candidate AGN pair (dual AGN), with a separation of ~5.5 kpc, in a galaxy at a redshift of z=1.175; this scenario would be the result of a galaxy merger and represent the stage prior to the formation of a binary SMBH. The second is the identification of similar candidate dual AGN sources in a systematic study of quasars at redshifts z=0.8-1.6. The final project analyzes follow-up long-slit spectroscopy of two quasars found through the systematic search which are most likely to host AGN-driven outflows. Overall, the combined results for these NLR studies show that a significant fraction of the double-peaked narrow emission lines are produced by AGN-driven outflows. Furthermore, diagnostics based upon ionization potentials can effectively select sources most likely to possess these outflows, and those which are more

  14. Inferring physical properties of galaxies from their emission-line spectra

    NASA Astrophysics Data System (ADS)

    Ucci, G.; Ferrara, A.; Gallerani, S.; Pallottini, A.

    2017-02-01

    We present a new approach based on Supervised Machine Learning algorithms to infer key physical properties of galaxies (density, metallicity, column density and ionization parameter) from their emission-line spectra. We introduce a numerical code (called GAME, GAlaxy Machine learning for Emission lines) implementing this method and test it extensively. GAME delivers excellent predictive performances, especially for estimates of metallicity and column densities. We compare GAME with the most widely used diagnostics (e.g. R23, [N II] λ6584/Hα indicators) showing that it provides much better accuracy and wider applicability range. GAME is particularly suitable for use in combination with Integral Field Unit spectroscopy, both for rest-frame optical/UV nebular lines and far-infrared/sub-millimeter lines arising from photodissociation regions. Finally, GAME can also be applied to the analysis of synthetic galaxy maps built from numerical simulations.

  15. Resonant Scattering of X-ray Emission Lines in the Hot Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Churazov, Eugene; Zhuravleva, Irina; Sazonov, Sergey; Sunyaev, Rashid

    2010-12-01

    While very often a hot intergalactic medium (IGM) is optically thin to continuum radiation, the optical depth in resonant lines can be of order unity or larger. Resonant scattering in the brightest X-ray emission lines can cause distortions in the surface brightness distribution, spurious variations in the abundance of heavy elements, changes in line spectral shapes and even polarization of line emission. The magnitude of these effects not only depends on the density, temperature and ionization state of the gas, but is also sensitive to the characteristics of the gas velocity field. This opens a possibility to use resonant scattering as a convenient and powerful tool to study IGM properties. We discuss the application of these effects to galaxy clusters.

  16. VizieR Online Data Catalog: Unidentified cometary emission lines (Simonia, 2004)

    NASA Astrophysics Data System (ADS)

    Simonia, I. A.

    2005-03-01

    We discuss the possible nature of unidentified cometary emission lines. We propose a model of the ice particles in cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons (PAHs) and acyclic hydrocarbons. We describe the general properties of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence of FHPs. We compare the position of quasi-lines in the spectrum of Comet 122P/de Vico with the position of quasi-lines in the photoluminescence spectrum of PAHs that were dissolved in acyclic hydrocarbons at a temperature of 77K and that constituted a polycrystalline solution. We estimated the detectability of FHP photoluminescence in cometary spectra. (1 data file).

  17. Spectro-astrometric Study of HI emission lines from Herbig Ae/Be Stars

    NASA Astrophysics Data System (ADS)

    Cade Adams, Steven; Brittain, Sean D.; Dougados, Catherine; Benisty, Myriam; Podio, Linda; Whelan, Emma

    2015-01-01

    We present a spectro-astrometric study of the Pa β and Br γ lines from six Herbig Ae/Be stars using NIFS on Gemini North. The goal of this study is to determine the origin of the HI emission lines. By combining the high angular resolution ( 0.1") and intermediate spectral resolution (R~5000) of GEMINI/NIFS we measured the spectro-astrometric signal of the Pa β and Br γ emission lines at the 0.1 mas level. The HAe stars showed no significant spectro-astrometric signal, while the HBe stars did show significant detections. We compare our results to models and discuss the implications for understanding the origin of the HI lines in Herbig Ae/Be stars and their utility for measuring the accretion rate. We also discuss various artifacts in the data and prospects for more sensitive measurements in the future.

  18. [A new automated method to identify emission line star from massive spectra].

    PubMed

    Pan, Jing-Chang; Zhang, Cai-Ming; Wei, Peng; Luo, A-Li; Zhao, Yong-Heng

    2012-06-01

    Stellar spectra are characterized by obvious absorption lines or absorption bands, while those with emission lines are usually special stars such as cataclysmic variable stars (CVs), HerbigAe/Be etc. The further study of this kind of spectra is meaningful. The present paper proposed a new method to identify emission line stars (ELS) spectra automatically. After the continuum normalization is done for the original spectral flux, line detection is made by comparing the normalized flux with the mean and standard deviation of the flux in its neighbor region The results of the experiment on massive spectra from SDSS DR8 indicate that the method can identify ELS spectra completely and accurately. Since no complex transformation and computation are involved in this method, the identifying process is fast and it is ideal for the ELS detection in large sky survey projects like LAMOST and SDSS.

  19. The filamentary nebula YM 29 - Spectrograms and emission-line photographs

    NASA Astrophysics Data System (ADS)

    Lozinskaya, T. A.; Sitnik, T. G.; Toropova, M. S.

    1986-04-01

    Spectrograms as well as monochromatic photographs and isophotes in three emission features have been obtained for YM 29, an old planetary nebula of Peimbert type PN I. The morphology depends on the ionization state: diffuse forbidden O III emission is accompanied by fine forbidden N II, forbidden S II filaments. Moreover the radiation is stratified, with regions bright in the forbidden O II line located 10-40 arcsec closer to the nucleus than the forbidden N II, forbidden S II emission sites. Similar morphology distinctions and stratification, typifying nebulae ionized by the central star's ultraviolet radiation, have previously been reported in a kindred object, Simeiz 22.

  20. The soft X-ray spectrum of Capella - Discovery of intense line emission

    NASA Technical Reports Server (NTRS)

    Cash, W.; Bowyer, S.; Charles, P. A.; Lampton, M.; Garmire, G.; Riegler, G.

    1978-01-01

    A soft X-ray spectrum of Capella has been obtained with the HEAO 1 satellite. Only models which include intense line emission at 0.85 keV can adequately explain the data. The spectrum is consistent with emission from an isothermal solar-abundance plasma with a temperature of 10.5 million (+ or - 2.8 million) K. It is also consistent with a blend of temperatures between 4 and 20 million K. The intensity of the X-ray emission is constant over 2 days and similar to the intensity observed by ANS.

  1. Method for measuring radial impurity emission profiles using correlations of line integrated signals

    NASA Astrophysics Data System (ADS)

    Kuldkepp, M.; Brunsell, P. R.; Drake, J.; Menmuir, S.; Rachlew, E.

    2006-04-01

    A method of determining radial impurity emission profiles is outlined. The method uses correlations between line integrated signals and is based on the assumption of cylindrically symmetric fluctuations. Measurements at the reversed field pinch EXTRAP T2R show that emission from impurities expected to be close to the edge is clearly different in raw as well as analyzed data to impurities expected to be more central. Best fitting of experimental data to simulated correlation coefficients yields emission profiles that are remarkably close to emission profiles determined using more conventional techniques. The radial extension of the fluctuations is small enough for the method to be used and bandpass filtered signals indicate that fluctuations below 10kHz are cylindrically symmetric. The novel method is not sensitive to vessel window attenuation or wall reflections and can therefore complement the standard methods in the impurity emission reconstruction procedure.

  2. Achieving EMC Emissions Compliance for an Aeronautics Power Line Communications System

    NASA Astrophysics Data System (ADS)

    Dominiak, S.; Vos, G.; ter Meer, T.; Widmer, H.

    2012-05-01

    Transmitting data over the power distribution network - Power Line Communications (PLC) -provides an interesting solution to reducing the weight and complexity of wiring networks in commercial aircraft. One of the potential roadblocks for the introduction of this technology is achieving EMC emissions compliance. In this article an overview of the EMC conducted and radiated emissions testing for PLC- enabled aeronautics equipment is presented. Anomalies resulting from chamber resonances leading to discrepancies between the conducted emissions tests and the measured radiated emissions are identified and described. Measurements made according to the current version of the civil aeronautical EMC standard, EUROCAE ED-14F (RTCA DO-160F), show that PLC equipment can achieve full EMC emissions compliance.

  3. DETECTION OF THE INTERMEDIATE-WIDTH EMISSION LINE REGION IN QUASAR OI 287 WITH THE BROAD EMISSION LINE REGION OBSCURED BY THE DUSTY TORUS

    SciTech Connect

    Li, Zhenzhen; Zhou, Hongyan; Wang, Huiyuan; Liu, Bo; Liu, Wen-Juan; Pan, Xiang; Jiang, Peng; Hao, Lei; Ji, Tuo; Shi, Xiheng; Zhang, Shaohua E-mail: zhouhongyan@pric.org.cn

    2015-10-20

    The existence of intermediate-width emission line regions (IELRs) in active galactic nuclei has been discussed for over two decades. A consensus, however, is yet to be arrived at due to the lack of convincing evidence for their detection. We present a detailed analysis of the broadband spectrophotometry of the partially obscured quasar OI 287. The ultraviolet intermediate-width emission lines (IELs) are very prominent, in high contrast to the corresponding broad emission lines (BELs) which are heavily suppressed by dust reddening. Assuming that the IELR is virialized, we estimated its distance to the central black hole to be ∼2.9 pc, similar to the dust sublimation radius of ∼1.3 pc. Photo-ionization calculations suggest that the IELR has a hydrogen density of ∼10{sup 8.8}–10{sup 9.4} cm{sup −3}, within the range of values quoted for the dusty torus near the sublimation radius. Both its inferred location and physical conditions suggest that the IELR originates from the inner surface of the dusty torus. In the spectrum of this quasar, we identified only one narrow absorption-line system associated with the dusty material. With the aid of photo-ionization model calculations, we found that the obscuring material might originate from an outer region of the dusty torus. We speculate that the dusty torus, which is exposed to the central ionizing source, may produce IELs through photo-ionization processes, as well as obscure BELs as a natural “coronagraph.” Such a “coronagraph” could be found in a large number of partially obscured quasars and may be a useful tool to study IELRs.

  4. Line shape of the non-thermal 6300 A O/1D/ emission

    NASA Technical Reports Server (NTRS)

    Schmitt, G. A.; Abreu, V. J.; Hays, P. B.

    1982-01-01

    The two-population model of Schmitt, Abreu and Hays (1981) is used to calculate the line shape of the atomic oxygen metastable state, nonthermal O(1D) 6300 A emission, in order to simulate observations made from a space platform at different zenith angles and altitudes. The Addition theorem, for spherical harmonics of a Legendre polynomial expansion of the nonthermal population distribution function, is used to obtain nonthermal line shapes observed at zenith angles other than the local vertical one.

  5. VizieR Online Data Catalog: Nebular emission lines towards NGC3372 center (Damiani+, 2016)

    NASA Astrophysics Data System (ADS)

    Damiani, F.; Bonito, R.; Magrini, L.; Prisinzano, L.; Mapelli, M.; Micela, G.; Kalari, V.; Maiz Apellaniz, J.; Gilmore, G.; Randich, S.; Alfaro, E.; Flaccomio, E.; Koposov, S.; Klutsch, A.; Lanzafame, A. C.; Pancino, E.; Sacco, G. G.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Worley, C.; Zaggia, S.; Zwitter, T.; Dorda, R.

    2016-04-01

    Nebular emission lines of H-alpha, [NII] 6584Å, HeI 6678Å, [SII] 6717Å, [SII] 6731Å, towards the center of Carina nebula, are modeled with two gaussians each ('blue' and 'red' components). Best-fit parameters are given in the table. Line widths include the instrumental width of the Giraffe spectrograph (7km/s). Radial velocities are heliocentric. (1 data file).

  6. 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.

  7. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    SciTech Connect

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; Dalla Bontà, E.; Ciroi, S.

    2013-12-20

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  8. Searching for Narrow Emission Lines in X-ray Spectra: Computation and Methods

    NASA Astrophysics Data System (ADS)

    Park, Taeyoung; van Dyk, David A.; Siemiginowska, Aneta

    2008-12-01

    The detection and quantification of narrow emission lines in X-ray spectra is a challenging statistical task. The Poisson nature of the photon counts leads to local random fluctuations in the observed spectrum that often result in excess emission in a narrow band of energy resembling a weak narrow line. From a formal statistical perspective, this leads to a (sometimes highly) multimodal likelihood. Many standard statistical procedures are based on (asymptotic) Gaussian approximations to the likelihood and simply cannot be used in such settings. Bayesian methods offer a more direct paradigm for accounting for such complicated likelihood functions, but even here multimodal likelihoods pose significant computational challenges. The new Markov chain Monte Carlo (MCMC) methods developed in 2008 by van Dyk and Park, however, are able to fully explore the complex posterior distribution of the location of a narrow line, and thus provide valid statistical inference. Even with these computational tools, standard statistical quantities such as means and standard deviations cannot adequately summarize inference and standard testing procedures cannot be used to test for emission lines. In this paper, we use new efficient MCMC algorithms to fit the location of narrow emission lines, we develop new statistical strategies for summarizing highly multimodal distributions and quantifying valid statistical inference, and we extend the method of posterior predictive p-values proposed by Protassov and coworkers to test for the presence of narrow emission lines in X-ray spectra. We illustrate and validate our methods using simulation studies and apply them to the Chandra observations of the high-redshift quasar PG 1634+706.

  9. THE SURVEY OF LINES IN M31 (SLIM): INVESTIGATING THE ORIGINS OF [C II] EMISSION

    SciTech Connect

    Kapala, M. J.; Sandstrom, K.; Groves, B.; Kreckel, K.; Schinnerer, E.; Walter, F.; Fouesneau, M.; Croxall, K.; Dalcanton, J.; Leroy, A.

    2015-01-01

    The [C II] 158 μm line is one of the strongest emission lines observed in star-forming galaxies and has been empirically measured to correlate with the star-formation rate (SFR) globally and on kiloparsec scales. However, because of the multiphase origins of [C II], one might expect this relation to break down at small scales. We investigate the origins of [C II] emission by examining high spatial resolution observations of [C II] in M31 with the Survey of Lines in M31. We present five ∼700 × 700 pc (3' × 3') fields mapping the [C II] emission, Hα emission, and the ancillary infrared (IR) data. We spatially separate star-forming regions from diffuse gas and dust emission on ∼50 pc scales. We find that the [C II]-SFR correlation holds even at these scales, although the relation typically has a flatter slope than found at larger (kiloparsec) scales. While the Hα emission in M31 is concentrated in the SFR regions, we find that a significant amount (∼20%-90%) of the [C II] emission comes from outside star-forming regions and that the total IR emission (TIR) has the highest diffuse fraction of all SFR tracers. We find a weak correlation of the [C II]/TIR to dust color in each field and find a large-scale trend of increasing [C II]/TIR with galactocentric radius. The differences in the relative diffuse fractions of [C II], Hα, and IR tracers are likely caused by a combination of energetic photon leakage from H II regions and heating by the diffuse radiation field arising from older (B-star) stellar populations. However, we find that by averaging our measurements over kiloparsec scales, these effects are minimized, and the relation between [C II] and SFR found in other nearby galaxy studies is retrieved.

  10. The Nature of Active Galactic Nuclei with Velocity Offset Emission Lines

    NASA Astrophysics Data System (ADS)

    Müller-Sánchez, F.; Comerford, J.; Stern, D.; Harrison, F. A.

    2016-10-01

    We obtained Keck/OSIRIS near-IR adaptive optics-assisted integral-field spectroscopy to probe the morphology and kinematics of the ionized gas in four velocity-offset active galactic nuclei (AGNs) from the Sloan Digital Sky Survey. These objects possess optical emission lines that are offset in velocity from systemic as measured from stellar absorption features. At a resolution of ˜0.″18, OSIRIS allows us to distinguish which velocity offset emission lines are produced by the motion of an AGN in a dual supermassive black hole system, and which are produced by outflows or other kinematic structures. In three galaxies, J1018+2941, J1055+1520, and J1346+5228, the spectral offset of the emission lines is caused by AGN-driven outflows. In the remaining galaxy, J1117+6140, a counterrotating nuclear disk is observed that contains the peak of Paα emission 0.″2 from the center of the galaxy. The most plausible explanation for the origin of this spatially and kinematically offset peak is that it is a region of enhanced Paα emission located at the intersection zone between the nuclear disk and the bar of the galaxy. In all four objects, the peak of ionized gas emission is not spatially coincident with the center of the galaxy as traced by the peak of the near-IR continuum emission. The peaks of ionized gas emission are spatially offset from the galaxy centers by 0.″1-0.″4 (0.1-0.7 kpc). We find that the velocity offset originates at the location of this peak of emission, and the value of the offset can be directly measured in the velocity maps. The emission-line ratios of these four velocity-offset AGNs can be reproduced only with a mixture of shocks and AGN photoionization. Shocks provide a natural explanation for the origin of the spatially and spectrally offset peaks of ionized gas emission in these galaxies. Based on observations at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the

  11. Different regions of line formation in the envelope of the early emission line star HD 190073

    NASA Technical Reports Server (NTRS)

    Ringuelet, A. E.; Rovira, M.; Cidale, L.; Sahade, J.

    1987-01-01

    A description is presented of the spectral features that characterize the spectrum of HD 190073 both in the photographic region (360-660 nm), and in the IUE UV (115-320 nm). A number of different types of profiles can be distinguished, and this seems to imply that many different 'broad' regions of line formation coexist in the extended envelope of the star, including regions with densities differing in several orders of magnitude.

  12. Different regions of line formation in the envelope of the early emission line star HD 190073

    NASA Technical Reports Server (NTRS)

    Ringuelet, A. E.; Rovira, M.; Cidale, L.; Sahade, J.

    1987-01-01

    A description is presented of the spectral features that characterize the spectrum of HD 190073 both in the photographic region (360-660 nm), and in the IUE UV (115-320 nm). A number of different types of profiles can be distinguished, and this seems to imply that many different 'broad' regions of line formation coexist in the extended envelope of the star, including regions with densities differing in several orders of magnitude.

  13. Solar Flare Termination Shock and Synthetic Emission Line Profiles of the Fe xxi 1354.08 Å Line

    NASA Astrophysics Data System (ADS)

    Guo, Lijia; Li, Gang; Reeves, Kathy; Raymond, John

    2017-09-01

    Solar flares are among the most energetic phenomena that occur in the solar system. In the standard solar flare model, a fast mode shock, often referred to as the flare termination shock (TS), can exist above the loop-top source of hard X-ray emissions. The existence of the TS has been recently related to spectral hardening of a flare’s hard X-ray spectra at energies >300 keV. Observations of the Fe xxi 1354.08 Å line during solar flares by the Interface Region Imaging Spectrograph (IRIS) spacecraft have found significant redshifts with >100 km s‑1, which is consistent with a reconnection downflow. The ability to detect such a redshift with IRIS suggests that one may be able to use IRIS observations to identify flare TSs. Using a magnetohydrodynamic simulation to model magnetic reconnection of a solar flare and assuming the existence of a TS in the downflow of the reconnection plasma, we model the synthetic emission of the Fe xxi 1354.08 line in this work. We show that the existence of the TS in the solar flare may manifest itself in the Fe xxi 1354.08 Å line.

  14. 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.

  15. Cr-K EMISSION LINE AS A CONSTRAINT ON THE PROGENITOR PROPERTIES OF SUPERNOVA REMNANTS

    SciTech Connect

    Yang, X. J.; Xiang, F. Y.; Xiao, H. P.; Zhong, J. X.; Tsunemi, H.; Lu, F. J.; Li, Aigen

    2013-03-20

    We perform a survey of the Cr, Mn, and Fe-K emission lines in young supernova remnants (SNRs) with the Japanese X-ray astronomy satellite Suzaku. The Cr and/or Mn emission lines are detected in 3C 397 and 0519-69.0 for the first time. We also confirm the detection of these lines in Kepler, W49B, N103B, and Cas A. We derive the line parameters (i.e., the line centroid energy, flux, and equivalent width (EW)) for these six sources and perform a correlation analysis for the line center energies of Cr, Mn, and Fe. Also included in the correlation analysis are Tycho and G344.7-0.1 for which the Cr, Mn, and Fe-K line parameters were available in the literature through Suzaku observations. We find that the line center energies of Cr correlate very well with that of Fe and that of Mn. This confirms our previous findings that Cr, Mn, and Fe are spatially co-located, share a similar ionization state, and have a common origin in the supernova nucleosynthesis. We find that the ratio of the EW of the Cr emission line to that of Fe ({gamma}{sub Cr/Fe}{identical_to}EW(Cr)/EW(Fe)) provides useful constraints on the SNR progenitors and on the SN explosion mechanisms: for SNRs with {gamma}{sub Cr/Fe} > 2%, a Type Ia origin is favored (e.g., N103B, G344.7-0.1, 3C 397, and 0519-69.0); for SNRs with {gamma}{sub Cr/Fe} < 2%, they could be of either core-collapse origin or carbon-deflagration Ia origin.

  16. 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.

  17. 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

  18. Searching for Dwarf H Alpha Emission-line Galaxies within Voids III: First Spectra

    NASA Astrophysics Data System (ADS)

    Moody, J. Ward; Draper, Christian; McNeil, Stephen; Joner, Michael D.

    2017-02-01

    The presence or absence of dwarf galaxies with {M}r\\prime > -14 in low-density voids is determined by the nature of dark matter halos. To better understand what this nature is, we are conducting an imaging survey through redshifted Hα filters to look for emission-line dwarf galaxies in the centers of two nearby galaxy voids called FN2 and FN8. Either finding such dwarfs or establishing that they are not present is a significant result. As an important step in establishing the robustness of the search technique, we have observed six candidates from the survey of FN8 with the Gillett Gemini telescope and GMOS spectrometer. All of these candidates had emission, although none was Hα. The emission in two objects was the [O iii]λ4959, 5007 doublet plus Hβ, and the emission in the remaining four was the [O ii]λ3727 doublet, all from objects beyond the void. While no objects were within the void, these spectra show that the survey is capable of finding emission-line dwarfs in the void centers that are as faint as {M}r\\prime ∼ -12.4, should they be present. These spectra also show that redshifts estimated from our filtered images are accurate to several hundred km s‑1 if the line is identified correctly, encouraging further work in finding ways to conduct redshift surveys through imaging alone.

  19. THE ULTRAVIOLET-TO-MID-INFRARED SPECTRAL ENERGY DISTRIBUTION OF WEAK EMISSION LINE QUASARS

    SciTech Connect

    Lane, Ryan A.; Shemmer, Ohad; Diamond-Stanic, Aleksandar M.; Fan Xiaohui; Anderson, Scott F.; Brandt, W. N.; Schneider, Donald P.; Plotkin, Richard M.; Richards, Gordon T.; Strauss, Michael A. E-mail: ohad@unt.edu

    2011-12-20

    We present Spitzer Space Telescope photometry of 18 Sloan Digital Sky Survey (SDSS) quasars at 2.7 {<=} z {<=} 5.9 which have weak or undetectable high-ionization emission lines in their rest-frame ultraviolet (UV) spectra (hereafter weak-lined quasars, or WLQs). The Spitzer data are combined with SDSS spectra and ground-based, near-infrared (IR) photometry of these sources to produce a large inventory of spectral energy distributions (SEDs) of WLQs across the rest-frame {approx}0.1-5 {mu}m spectral band. The SEDs of our sources are inconsistent with those of BL Lacertae objects which are dominated by synchrotron emission due to a jet aligned close to our line of sight, but are consistent with the SED of ordinary quasars with similar luminosities and redshifts that exhibit a near-to-mid-IR 'bump', characteristic of hot dust emission. This indicates that broad emission lines in WLQs are intrinsically weak, rather than suffering continuum dilution from a jet, and that such sources cannot be selected efficiently from traditional photometric surveys.

  20. A high resolution catalogue of emission lines of comet C/2000 WM1 (linear)

    NASA Astrophysics Data System (ADS)

    Picazzio, E.; de Almeida, A.; Churyumov, K.; Andrievskii, S.; Lukyanyk, I.

    Since at present our knowledge about the chemical composition of the nucleus of a comet is all indirect, optical spectroscopy is one of the main tools to provide information about this composition and help in the planning and design of instrumentation for experiments in future space missions. Using five high-resolution spectra of comet C/2000 WM1 (LINEAR) obtained on Dec. 1 and 2, 2001 (UT) with the Fiber fed Extended Range Optical Spectrograph (FEROS) installed on the 1.52-m reflector of the ESO (Chile, La Silla), we have constructed a catalogue of cometary emission lines for this comet. Many of the emission lines of the molecules C , C3, CN, CH, CH+, NH 2, CO +, H2O+, and2 presumably CO and C- identified in the spectral range 4000-9000 ÅÅ in the2 comet's spectra. The total number of identified emission lines is 4537: C2 - 2734, NH2 - 1195, CN - 289, C3 - 158, CO - 60, H 2O+ - 51, CH - 50, CO+ - 16, CH+ - 8, C 2- - 5. Also there are many unidentified emission lines in the comet's spectra.

  1. A commercial tunable diode laser (TDL) system for on-line remote measurements of automobile emissions

    NASA Astrophysics Data System (ADS)

    Weber, Konradin; Ropertz, Alexander; Schwabe, Thomas; Fischer, Christian; van Haren, Gunther

    2004-11-01

    An innovative tunable diode laser (TDL) measurement system has been used for the on-line estimation of emissions of cars, driving through the measurement beam of the system. This paper describes the measurement principle and gives first measurement results, taken for different types of cars.

  2. The implications of grading on the emission line width of core–shell nanocrystals

    NASA Astrophysics Data System (ADS)

    Phadnis, Chinmay; Sonawane, Kiran G.; Sudarsan, V.; Mahamuni, Shailaja

    2017-04-01

    An excitonic coupling with phonons leads to broadening of the emission line. The narrow excitonic emission line width observed in CdZnS/ZnS alloy core graded shell nanocrystals (NCs) with varying compositions is studied using temperature-dependent photoluminescence measurements. Contrary to the consensus that a narrow emission line width is observable with a reduction in size (due to the increased exciton–acoustic phonon coupling coefficient σ), an increased value is noted with reduced size. Based on a theoretical approach to graded core–shell NCs, the relationship between the electron–hole wave function overlap and exciton lifetime is invoked to understand this anomaly. Smaller alloy core–shell NCs (CdZnS/ZnS-I) have a longer lifetime than larger NCs (CdZnS/ZnS-II), indicating reduced electron–hole wave function overlap for CdZnS/ZnS-I NCs and hence a larger ‘effective size’ of NCs, even though the actual size is smaller. The experimental findings demonstrate that graded core–shell NCs reveal an additional functionality, facilitating control of the emission line width of NCs via minimal interaction with the solid state environment.

  3. An atlas of emission line fluxes of planetary nebulae in the 1150-3200 A region

    NASA Technical Reports Server (NTRS)

    Feibelman, W. A.; Mccracken, C. W.

    1981-01-01

    Emission line fluxes for 28 planetary nebulae are presented. The nebulae were chosen to cover a wide range of excitation classes, apparent diameters, location in the sky, and types of central stars. All objects were observed in the low dispersion mode of the IUE spectrographs, using the large entrance aperture.

  4. Cross section calculations of astrophysical interest. [for theories of absorption and emission lines

    NASA Technical Reports Server (NTRS)

    Gerjuoy, E.

    1974-01-01

    Cross sections are discussed for rotational excitation associated with theories of absorption and emission lines from molecules in space with emphasis on H2CO, CO, and OH by collisions with neutral particles such H, H2, and He. The sensitivity of the Thaddeus equation for the H2CO calculation is examined.

  5. The Importance of Nebular Continuum and Line Emission in Observations of Young Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Nidever, David L.; Whelan, David G.; Johnson, Kelsey E.

    2010-01-01

    In this spectroscopic study of infant massive star clusters, we find that continuum emission from ionized gas rivals the stellar luminosity at optical wavelengths. In addition, we find that nebular line emission is significant in many commonly used broadband Hubble Space Telescope (HST) filters including the F814W I-band, the F555W V-band, and the F435W B-band. Two young massive clusters (YMCs) in the nearby starburst galaxy NGC 4449 were targeted for follow-up spectroscopic observations after Reines et al. discovered an F814W I-band excess in their photometric study of radio-detected clusters in the galaxy. The spectra were obtained with the Dual Imaging Spectrograph (DIS) on the 3.5 m Apache Point Observatory (APO) telescope and have a spectral range of ~3800-9800 Å. We supplement these data with HST and Sloan Digital Sky Survey photometry of the clusters. By comparing our data to the Starburst99 and GALEV evolutionary synthesis models, we find that nebular continuum emission competes with the stellar light in our observations and that the relative contribution from the nebular continuum is largest in the U- and I-bands, where the Balmer (3646 Å) and Paschen jumps (8207 Å) are located. The spectra also exhibit strong line emission including the [S III] λλ9069, 9532 lines in the HST F814W I-band. We find that the combination of nebular continuum and line emission can account for the F814W I-band excess previously found by Reines et al. In an effort to provide a benchmark for estimating the impact of ionized gas emission on photometric observations of young massive stellar populations, we compute the relative contributions of the stellar continuum, nebular continuum, and emission lines to the total observed flux of a 3 Myr old cluster through various HST filter/instrument combinations, including filters in the Wide Field Camera 3. We urge caution when comparing observations of YMCs to evolutionary synthesis models since nebular continuum and line emission can

  6. Detection of emission lines from z ˜ 3 DLAs towards the QSO J2358+0149

    NASA Astrophysics Data System (ADS)

    Srianand, Raghunathan; Hussain, Tanvir; Noterdaeme, Pasquier; Petitjean, Patrick; Krühler, Thomas; Japelj, Jure; Pâris, Isabelle; Kashikawa, Nobunari

    2016-07-01

    Using VLT/X-shooter, we searched for emission line galaxies associated with four damped Lyman α systems (DLAs) and one sub-DLA at 2.73 ≤z ≤3.25 towards QSO J2358+0149. We detect [O III] emission from a `low-cool' DLA at zabs = 2.9791 (having log N(H I) = 21.69 ± 0.10, [Zn/H] = -1.83 ± 0.18) at an impact parameter of, ρ ˜ 12 kpc. The associated galaxy is compact with a dynamical mass of (1-6) × 109 M⊙, very high excitation ([O III]/[O II] and [O III]/[Hβ] both greater than 10), 12+[O/H]≤8.5 and moderate star formation rate (SFR ≤2 M⊙ yr-1). Such properties are typically seen in the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is inconsistent with that of an extended disc and the gas is part of either a large scale wind or cold accretion. We detect Lyα emission from the zabs = 3.2477 DLA [having log N(H I) = 21.12 ± 0.10 and [Zn/H] = -0.97 ± 0.13]. The Lyα emission is redshifted with respect to the metal absorption lines by 320 km s-1, consistent with the location of the red hump expected in radiative transport models. We derive SFR ˜0.2-1.7 M⊙ yr-1 and Lyα escape fraction of ≥10 per cent. No other emission line is detected from this system. Because the DLA has a small velocity separation from the quasar (˜500 km s-1) and the DLA emission is located within a small projected distance (ρ < 5 kpc), we also explore the possibility that the Lyα emission is being induced by the QSO itself. QSO-induced Lyα fluorescence is possible if the DLA is within a physical separation of 340 kpc to the QSO. Detection of stellar continuum light and/or the oxygen emission lines would disfavour this possibility. We do not detect any emission line from the remaining three systems.

  7. Detection of an oxygen emission line from a high-redshift galaxy in the reionization epoch.

    PubMed

    Inoue, Akio K; Tamura, Yoichi; Matsuo, Hiroshi; Mawatari, Ken; Shimizu, Ikkoh; Shibuya, Takatoshi; Ota, Kazuaki; Yoshida, Naoki; Zackrisson, Erik; Kashikawa, Nobunari; Kohno, Kotaro; Umehata, Hideki; Hatsukade, Bunyo; Iye, Masanori; Matsuda, Yuichi; Okamoto, Takashi; Yamaguchi, Yuki

    2016-06-24

    The physical properties and elemental abundances of the interstellar medium in galaxies during cosmic reionization are important for understanding the role of galaxies in this process. We report the Atacama Large Millimeter/submillimeter Array detection of an oxygen emission line at a wavelength of 88 micrometers from a galaxy at an epoch about 700 million years after the Big Bang. The oxygen abundance of this galaxy is estimated at about one-tenth that of the Sun. The nondetection of far-infrared continuum emission indicates a deficiency of interstellar dust in the galaxy. A carbon emission line at a wavelength of 158 micrometers is also not detected, implying an unusually small amount of neutral gas. These properties might allow ionizing photons to escape into the intergalactic medium. Copyright © 2016, American Association for the Advancement of Science.

  8. 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.

  9. On-line field measurements of VOC emissions from a spruce tree at SMEAR Estonia

    NASA Astrophysics Data System (ADS)

    Bourtsoukidis, Efstratios; Bonn, Boris; Noe, Steffen

    2013-04-01

    We have investigated VOC emissions from a Norway spruce tree (Picea abies) in a hemi-boreal mixed forest in September and October 2012, using Proton Transfer Reaction Mass Spectrometry and Gas Chromatography - Mass Spectrometry techniques, applied in a dynamic branch enclosure system that was automatically operated with an electrical compressor. Parallel to BVOC measurements a vast amount of atmospheric (CO2, CH4, H2O, CO, particles) and meteorological (temperature, relative humidity, photosynthetic active radiation, wind speed and direction, precipitation) parameters were measured in the ambient atmosphere and inside the cuvette enclosure (temperature, relative humidity, O3). Prior to the measuring period, an innovatory experimental setup was built at Järvselja forest station, in order to accomplish the detection of BVOC and minimize sampling losses. Therefore, a new inlet line, consisting of 19.4m of heated and isolated glass tube was constructed. The new inlet system applied, allowed the on-line detection and calculation of sesquiterpene (SQT) emission rates for the first time in a hemi-boreal forest site. It total, 12 atmospheric relevant BVOCs were continuously monitored for a three week period and the emission rates were derived. Along with diurnal profiles and continuous timeless, some interesting observations showed the possibility of ozone effect on SQT emissions, the possibility of radiation effect on MT emissions, the higher induced emissions due to mechanical stress and the possibility for a valid intercomparison between different spruce trees located in mountain Kleiner Feldberg (Germany) and in Järvseja forest station (Estonia).

  10. XMM-Newton observations of GX 13 + 1: correlation between photoionised absorption and broad line emission

    NASA Astrophysics Data System (ADS)

    Díaz Trigo, M.; Sidoli, L.; Boirin, L.; Parmar, A. N.

    2012-07-01

    We analysed data from five XMM-Newton observations of GX 13 + 1 to investigate the variability of the photo-ionised absorber in this source. We fitted EPIC and RGS spectra obtained from the "least-variable" intervals with a model consisting of disc-blackbody and blackbody components together with a Gaussian emission feature at ~6.55-6.7 keV modified by absorption due to cold and photo-ionised material. We found a significant correlation between the hard, ~6-10 keV, flux, the ionisation and column density of the absorber and the equivalent width of the broad iron line. We interpret the correlation in a scenario in which a disc wind is thermally driven at large, ~1010 cm, radii and the broad line results from reprocessed emission in the wind and/or hot atmosphere. The breadth of the emission line is naturally explained by a combination of scattering, recombination and fluorescence processes. We attribute the variations in the absorption and emission along the orbital period to the view of different parts of the wind, possibly located at slightly different inclination angles. We constrain the inclination of GX 13 + 1 to be between 60 and 80° from the strong absorption in the line of sight, which obscures up to 80% of the total emission in one observation, and the absence of eclipses. We conclude that either a disc wind and/or a hot atmosphere can explain the current observations of narrow absorption and broad iron emission features in neutron star low-mass X-ray binaries as a class.

  11. An analysis of emission lines in the spectrum of P Cygni.

    NASA Astrophysics Data System (ADS)

    Markova, N.; de Groot, M.

    1997-10-01

    Using the coude spectrograph of the NAO 2m telescope at the Rhodope Mountains, Bulgaria, 9 spectra in the blue and 8 spectra in the red photographic region of P Cygni were obtained during 1990. By averaging the spectra in each set a S/N-ratio of about 45 was achieved. Comparing the lists of identifications published by Beals (1950PDAO....9....1B), de Groot (1969BAN....20..225D), Ozemre (1978PIstO.101....1O), Stahl et al. (1993A&AS...99..167S), Markova (1994A&AS..108..561M) and Markova & Zamanov (1995A&AS..114..499M), we conclude that the emission spectrum of P Cygni in our days is probably much richer and intensive than 60 years ago. A number of line parameters of the pure emission lines are measured. An estimate of the electron density and temperature in the region of [NII]-lines formation is obtained. Different velocity laws yielding similar density structures are discussed aiming to account for the results obtained on the basis of the [NII] lines. Possible mechanisms for the formation of the permitted pure emission-line spectrum are proposed.

  12. CO (2-1) LINE EMISSION IN REDSHIFT 6 QUASAR HOST GALAXIES

    SciTech Connect

    Wang Ran; Wagg, Jeff; Carilli, Chris L.; Walter, Fabian; Riechers, Dominick A.; Willott, Chris; Bertoldi, Frank; Omont, Alain; Bergeron, Jacqueline; Beelen, Alexandre; Cox, Pierre; Strauss, Michael A.; Forveille, Thierry; Menten, Karl M.; Fan, Xiaohui

    2011-09-20

    We report new observations of CO (2-1) line emission toward five z {approx} 6 quasars using the Ka-band receiver system on the Expanded Very Large Array (EVLA). Strong detections were obtained in two of them, SDSS J092721.82+200123.7 and CFHQS J142952.17+544717.6, and a marginal detection was obtained in another source, SDSS J084035.09+562419.9. Upper limits of the CO (2-1) line emission have been obtained for the other two objects. The CO (2-1) line detection in J0927+2001 together with previous measurements of the CO (6-5) and (5-4) lines reveal important constraints on the CO excitation in the central {approx}10 kpc region of the quasar host galaxy. The CO (2-1) line emission from J1429+5447 is resolved into two distinct peaks separated by 1.''2 ({approx}6.9 kpc), indicating a possible gas-rich, major merging system, and the optical quasar position is consistent with the west peak. This result is in good agreement with the picture in which intense host galaxy star formation is coeval with rapid supermassive black hole (SMBH) accretion in the most distant universe. The two EVLA detections are ideal targets for further high-resolution imaging (e.g., with ALMA or EVLA observations) to study the gas distribution, dynamics, and SMBH-bulge-mass relation in these earliest quasar host galaxy systems.

  13. Calibration of H-alpha/H-beta Indexes for Emission Line Objects

    NASA Astrophysics Data System (ADS)

    Hintz, Eric G.; Joner, Michael D.

    2016-01-01

    In Joner and Hintz (2015) they report on a standard star system for calibration of H-alpha and H-beta observations. This work was based on data obtained with the Dominion Astrophysical Observatory 1.2-m telescope. As part of the data acquisition for that project, a large number of emission line objects were also observed. We will report on the preliminary results for the emission line data set. This will include a comparison of equivalent width measurements of each line with the matching index. We will also examine the relation between the absorption line objects previously published and the emission line objects, along with a discussion of the transition point. Object types included are Be stars, high mass x-ray binaries, one low mass x-ray binary, Herbig Ae/Be stars, pre-main sequence stars, T Tauri stars, young stellar objects, and one BY Draconis star. Some of these objects come from Cygnus OB-2, NGC 659, NGC 663, NGC 869 and NGC 884.

  14. The First Unbiased Radio Emission Line Survey of the Protoplanetary Disk Orbiting Lkca 15

    NASA Astrophysics Data System (ADS)

    Punzi, Kristina Marie; Kastner, Joel H.; Hily-Blant, Pierre; Forveille, Thierry; Sacco, G. G.

    2014-06-01

    We have conducted the first comprehensive mm-wave molecular emission line survey of the circumstellar disk orbiting the nearby, pre-main sequence (T Tauri) star LkCa 15 (D = 140 pc). The outer disk is chemically rich, with numerous previous detections of molecular emission lines revealing a significant gas mass. The disk around this young (˜3-5 Myr), actively accreting solar analog likely hosts a young protoplanet (LkCa 15b) within its central cavity. Hence, LkCa 15 is an excellent target for an unbiased radio spectroscopic survey intended to produce a full census of the detectable molecular species within an evolved, protoplanetary disk. Our survey of LkCa 15 was conducted with the Institute de Radioastronomie Millimétrique (IRAM) 30 meter telescope over the 1.1-1.4 mm wavelength range. The survey includes detections of the three most abundant CO isotopologues (12CO, 13CO, and C18O) which facilitate estimates of the spatially integrated CO emission line optical depths, and complete coverage of the hyperfine line complexes of CN and C2H that provide diagnostics of excitation and opacity for these species. This work demonstrates the value of comprehensive single-dish line surveys in guiding future high resolution interferometric imaging by ALMA of protoplanetary disks orbiting T Tauri stars.

  15. On the diversity of the broad emission-line profiles in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Robinson, A.

    1995-02-01

    The profiles of the broad emission lines in active galactic nuclei (AGN) vary widely in both width and shape between objects. This diversity has important consquences for models of AGN. If the conventional view that the linewidths reflect bulk velocities of the emitting gas is correct, then differences in profile shape indicate that the structure and dynamics of the broad-line region may also differ among the AGN population, even within the same phenomenological class. In this paper, the nature and possible origin of the profile diversity are discussed in terms of a simple model based on a parametrization of some basic properties of the BLR-the radial depth, line emissivity distribution and velocity law-which govern the shape of the emitted line profile. For a given geometrical configuration, the profiles produced by this model can be characterized in terms of the relative width of the core and the curvature of the wings. It is proposed that variations in both of these properties are required to account for the diversity of the Hα and Hβ profiles in a sample of Seyfert galaxies. It is not possible to identify the underlying variables unambiguously, but in this interpretation the observed profile diversity implies variations in both the slope of the line emissivity distribution and either the radial depth or the velocity law. Variations in the former two properties imply in turn that the effective size of the BLR also varies among AGN, regardless of continuum luminosity. Several consequences which follow from this are briefly discussed.

  16. A z ∼ 5.7 Lyα emission line with an ultrabroad red wing

    SciTech Connect

    Yang, Huan; Wang, JunXian; Zheng, Zhen-Ya; Malhotra, Sangeeta; Rhoads, James E.; Infante, Leopoldo E-mail: jxw@mail.ustc.edu.cn E-mail: smalhotr@asu.edu E-mail: linfante@astro.puc.cl

    2014-03-20

    Using the Lyα emission line as a tracer of high-redshift, star-forming galaxies, hundreds of Lyα emission line galaxies (LAEs) at z > 5 have been detected. These LAEs are considered to be low-mass young galaxies, critical to the re-ionization of the universe and the metal enrichment of the circumgalactic medium (CGM) and the intergalactic medium (IGM). It is assumed that outflows in LAEs can help both ionizing photons and Lyα photons escape from galaxies. However, we still know little about the outflows in high-redshift LAEs due to observational difficulties, especially at redshift >5. Models of Lyα radiative transfer predict asymmetric Lyα line profiles with broad red wings in LAEs with outflows. Here, we report a z ∼ 5.7 Lyα emission line with a broad red wing extending to >1000 km s{sup –1} relative to the peak of Lyα line, which has been detected in only a couple of z > 5 LAEs until now. If the broad red wing is ascribed to gas outflow instead of active galactic nucleus activity, the outflow velocity could be larger than the escape velocity (∼500 km s{sup –1}) of a typical halo mass of z ∼ 5.7 LAEs, which is consistent with the idea that outflows in LAEs disperse metals to CGM and IGM.

  17. Weak Emission-line Quasars in the Context of a Modified Baldwin Effect

    NASA Astrophysics Data System (ADS)

    Shemmer, Ohad

    2016-01-01

    Based on spectroscopic data for a sample of high-redshift quasars, I will show that the anti-correlation between the rest-frame equivalent width (EW) of the C IV λ1549 broad-emission line and the Hβ-based Eddington ratio extends across the widest possible ranges of redshift (0 < z < 3.5) and bolometric luminosity(~1044 < L < ~1048 erg s-1). Given this anti-correlation, hereby referred to as a modified Baldwin effect (MBE), weak emission line quasars (WLQs), typically showing EW(C IV) < ~10 Å, are expected to have extremely high Eddington ratios (L/LEdd > ~4). I will present new near-infrared spectroscopy of the broad Hβ line, as well as complementary EW(C IV) information, for all WLQs for which such information is currently available, nine sources in total. I will show that while four of these WLQs can be accommodated by the MBE, the otherfive deviate significantly from this relation, at the > ~3σ level, by exhibiting C IV lines much weaker than predicted from their Hβ-based Eddington ratios. Assuming the supermassive black hole masses in all quasars can be determined reliably using the single-epoch Hβ-method, these results indicate that EW(C IV)cannot depend solely on the Eddington ratio. I will briefly discuss a strategy for further investigation into the roles that basic physical properties play in controlling the relative strengths of broad-emission lines in quasars.

  18. Hot surface ionic line emission and cold K-inner shell emission from petawatt-laser irradiated Cu foil targets

    SciTech Connect

    Theobald, W; Akli, K; Clarke, R; Delettrez, J A; Freeman, R R; Glenzer, S; Green, J; Gregori, G; Heathcote, R; Izumi, N; King, J A; Koch, J A; Kuba, J; Lancaster, K; MacKinnon, A J; Key, M; Mileham, C; Myatt, J; Neely, D; Norreys, P A; Park, H; Pasely, J; Patel, P; Regan, S P; Sawada, H; Shepherd, R; Snavely, R; Stephens, R B; Stoeckl, C; Storm, M; Zhang, B; Sangster, T C

    2005-12-13

    A hot, T{sub e} {approx} 2- to 3-keV surface plasma was observed in the interaction of a 0.7-ps petawatt laser beam with solid copper-foil targets at intensities >10{sup 20} W/cm{sup 2}. Copper K-shell spectra were measured in the range of 8 to 9 keV using a single-photon-counting x-ray CCD camera. In addition to K{sub {alpha}} and K{sub {beta}} inner-shell lines, the emission contained the Cu He{sub {alpha}} and Ly{sub {alpha}} lines, allowing the temperature to be inferred. These lines have not been observed previously with ultrafast laser pulses. For intensities less than 3 x 10{sup 18} W/cm{sup 2}, only the K{sub {alpha}} and K{sub {beta}} inner-shell emissions are detected. Measurements of the absolute K{sub {alpha}} yield as a function of the laser intensity are in agreement with a model that includes refluxing and confinement of the suprathermal electrons in the target volume.

  19. Identification of emission lines in the low-ionization strontium filament near Eta Carinae

    NASA Astrophysics Data System (ADS)

    Hartman, H.; Gull, T.; Johansson, S.; Smith, N.; HST Eta Carinae Treasury Project Team

    2004-05-01

    We have obtained deep spectra from 1640 to 10 100 Å with the Space Telescope Imaging Spectrograph (STIS) of the strontium filament, a largely neutral emission nebulosity lying close to the very luminous star Eta Carinae and showing an uncommon spectrum. Over 600 emission lines, both permitted and forbidden, have been identified. The majority originates from neutral or singly-ionized iron group elements (Sc, Ti, V, Cr, Mn, Fe, Co, Ni). Sr is the only neutron capture element detected. The presence of Sr II, numerous strong Ti II and V II lines and the dominance of Fe I over Fe II are notable discoveries. While emission lines of hydrogen, helium, and nitrogen are associable with other spatial structures at other velocities within the Homunculus, no emission lines from these elements correspond to the spatial structure or velocity of the \\ion{Sr} filament. Moreover, no identified \\ion{Sr} filament emission line requires an ionization or excitation energy above approximately 8 eV. Ionized gas extends spatially along the aperture, oriented along the polar axis of the Homunculus, and in velocity around the strontium filament. We suggest that the strontium filament is shielded from ultraviolet radiation at energies above 8 eV, but is intensely irradiated by the central star at wavelengths longward of 1500 Å. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. 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/419/215

  20. Spectral classification indicators of emission-line galaxies from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Shi, Fei; Liu, Yu-Yan; Li, Pei-Yu; Yu, Ming; Lei, Yu-Ming; Wang, Jian

    2015-07-01

    To find efficient spectral classification diagrams to classify emission-line galaxies, especially in large surveys and huge data bases, an artificial neural network (ANN) supervised learning algorithms is applied to a sample of emission-line galaxies from the Sloan Digital Sky Survey data release 9 provided by the Max Planck Institute and the Johns Hopkins University (MPA/JHU) (http://www.sdss3.org/dr9/spectro/spectroaccess.php). A two-step approach is adopted. (i) The ANN network must be trained with a subset of objects that are known to be active galactic nuclei (AGNs) hosts, composites or star-forming galaxies, treating the strong emission-line flux measurements as input feature vectors in n-dimensional space, where n is the number of strong emission-line flux ratios. (ii) After the network is trained on a sample of galaxies, the remaining galaxies are classified in the automatic test analysis as AGN hosts, composites or star-forming galaxies. We show that the classification diagrams based on the [N II]/Hα versus other emission-line ratio, such as [O III]/Hβ, [Ne III]/[O II], ([O III]λ4959 + [O III]λ5007)/[O III]λ4363, [O II]/Hβ, [Ar III]/[O III], [S II]/Hα, and [O I]/Hα, plus colour, allows us to separate unambiguously AGN hosts, composites or star-forming galaxies. Among them, the diagram of [N II]/Hα versus [O III]/Hβ achieved an accuracy of 98 per cent for classification of AGN hosts, composites or star-forming galaxies. The other diagrams above except the diagram of [N II]/Hα versus [O III]/Hβ give an accuracy of ˜90 per cent. The code in the paper is available on the web (http://fshi5388.blog.163.com).

  1. Bayesian Redshift Classification of Emission-line Galaxies with Photometric Equivalent Widths

    NASA Astrophysics Data System (ADS)

    Leung, Andrew S.; Acquaviva, Viviana; Gawiser, Eric; Ciardullo, Robin; Komatsu, Eiichiro; Malz, A. I.; Zeimann, Gregory R.; Bridge, Joanna S.; Drory, Niv; Feldmeier, John J.; Finkelstein, Steven L.; Gebhardt, Karl; Gronwall, Caryl; Hagen, Alex; Hill, Gary J.; Schneider, Donald P.

    2017-07-01

    We present a Bayesian approach to the redshift classification of emission-line galaxies when only a single emission line is detected spectroscopically. We consider the case of surveys for high-redshift Lyα-emitting galaxies (LAEs), which have traditionally been classified via an inferred rest-frame equivalent width (EW {W}{Lyα }) greater than 20 Å. Our Bayesian method relies on known prior probabilities in measured emission-line luminosity functions and EW distributions for the galaxy populations, and returns the probability that an object in question is an LAE given the characteristics observed. This approach will be directly relevant for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), which seeks to classify ˜106 emission-line galaxies into LAEs and low-redshift [{{O}} {{II}}] emitters. For a simulated HETDEX catalog with realistic measurement noise, our Bayesian method recovers 86% of LAEs missed by the traditional {W}{Lyα } > 20 Å cutoff over 2 < z < 3, outperforming the EW cut in both contamination and incompleteness. This is due to the method’s ability to trade off between the two types of binary classification error by adjusting the stringency of the probability requirement for classifying an observed object as an LAE. In our simulations of HETDEX, this method reduces the uncertainty in cosmological distance measurements by 14% with respect to the EW cut, equivalent to recovering 29% more cosmological information. Rather than using binary object labels, this method enables the use of classification probabilities in large-scale structure analyses. It can be applied to narrowband emission-line surveys as well as upcoming large spectroscopic surveys including Euclid and WFIRST.

  2. The Emission Line AGN Census: Biases of Line Ratio Selection, and Uniform Black Hole Accretion Regardless of Galaxy Mass

    NASA Astrophysics Data System (ADS)

    Trump, Jonathan R.; Zeimann, Gregory; Juneau, Stephanie; Sun, Mouyuan; Luck, Cuyler

    2015-01-01

    Optical emission line ratios offer a powerful tool to reveal accretion onto supermassive black holes, with the ability to find both unobscured and obscured active galactic nuclei (AGNs) in extraordinarily large galaxy samples (like the SDSS). I will demonstrate, however, that classic line ratio selection techniques significantly underestimate the AGN fraction by a factor of >10 in low-mass and star-forming galaxies. Previous conclusions that AGNs require massive green-valley hosts are purely a result of this "star formation dilution" bias. Careful treatment of the biases reveals that AGN accretion is uniform across star-forming galaxies of any stellar mass, similar to the results of bias-corrected X-ray AGN studies. This has dramatic implications for AGN feedback in dwarf galaxies and constraints on the black hole seed population.

  3. Plasma Core Electron Density and Temperature Measurements Using CVI Line Emissions in TCABR Tokamak

    NASA Astrophysics Data System (ADS)

    do Nascimento, F.; Machida, M.; Severo, J. H. F.; Sanada, E.; Ronchi, G.

    2015-08-01

    In this work, we present results of electron temperature ( T e ) and density ( n e ) measurements obtained in Tokamak Chauffage Alfvén Brésilien (TCABR) tokamak using visible spectroscopy from CVI line emissions which occurs mainly near the center of the plasma column. The presented method is based on a well-known relationship between the particle flux ( Γ ion) and the photon flux ( ø ion) emitted by an ion species combined with ionizations per photon atomic data provided by the atomic data and analysis structure (ADAS) database. In the experiment, we measured the photon fluxes of three different CVI spectral line emissions, 4685.2, 5290.5, and 6200.6 Å (one line per shot). Using this method it was possible to find out the temporal evolution of T e and n e in the plasma. The results achieved are in good agreement with T e and n e measurements made using other diagnostic tools.

  4. Feasibility of stimulated emission to measure {ital R}-line shifts in shock compressed ruby

    SciTech Connect

    Knudson, M.D.; Gupta, Y.M.

    1999-05-01

    In previous studies, ruby {ital R}-line shifts under shock compression and tension have been measured using the spontaneous luminescence from optically pumped samples. The signal intensities obtained are limited by the short time duration of the experiments in comparison to the long lifetime of the luminescence. We have investigated the use of stimulated emission for measuring {ital R}-line shifts in shocked ruby crystals. Experiments were performed both at ambient conditions and under shock compression to 6 GPa using an experimental configuration similar to that used for time resolved ruby luminescence measurements in previous shock wave studies. Signal gain due to stimulated emission was observed, with gains ranging from 1.1 to 3.4, in agreement with calculations performed for the particular experimental configuration used. The present results make a good case for incorporating this technique into the measurement of shock induced {ital R}-line shifts in ruby. {copyright} {ital 1999 American Institute of Physics.}

  5. COMPTEL upper limits on gamma-ray line emission from Supernova 1991T

    NASA Technical Reports Server (NTRS)

    Lichti, G. G.; Bennett, K.; Herder, J. W. Den; Diehl, R.; Morris, D.; Ryan, J.; Schoenfelder, V.; Steinle, H.; Strong, A. W.; Winkler, C.

    1994-01-01

    The imaging Compton telescope COMPTEL on board the Compton Gamma-Ray Observatory (CGRO) measures gamma-rays in the energy range 0.75-30 MeV with an energy resolution of 9.7% full width at half maximum (FWHM) at 1 MeV. From June 15 to 28, 1991 and again from October 3 to 17, 1991 the region containing the supernova SN 1991T was observed. A search for gamma-ray line emission from the supernova yields no detection of line emission from the supernova. 2 sigma upper limits for the two predicted lines at 847 keV and at 1.238 MeV of approximately equal to 3 x 10(exp -5) photons/(sq cm)(s) were derived. These limits are compared with the predictions of some theoretical models and constraints imposed by these limits on these models are discussed.

  6. A new Fabry-Perot spectrometer for observations of diffuse near-infrared line emission

    NASA Technical Reports Server (NTRS)

    Luhman, M. L.; Jaffe, D. T.; Keller, L. D.; Soojong, Pak

    1995-01-01

    We describe a new Fabry-Perot spectrometer that is optimized for the detection of extended, low-surface-brightness line emission from 1.4 to 2.4 microns. The instrument combines high throughput and high sensitivity, yet limits the background radiation falling on the detector. The instrument has a single 20 sec - 200 sec beam and a resolving power lambda/delta(lambda) approximately 2500. The system is background shot-noise limited in the K window and limited by a combination of read noise, dark-current shot noise, and fluctuations in the OH airglow lines in the H window. We present sample data of some of the lowest-surface-brightness H2 line emission in the near infrared obtained to date.

  7. A photoionization model for the optical line emission from cooling flows

    NASA Technical Reports Server (NTRS)

    Donahue, Megan; Voit, G. M.

    1991-01-01

    The detailed predictions of a photoionization model previously outlined in Voit and Donahue (1990) to explain the optical line emission associated with cooling flows in X-ray emitting clusters of galaxies are presented. In this model, EUV/soft X-ray radiation from condensing gas photoionizes clouds that have already cooled. The energetics and specific consequences of such a model, as compared to other models put forth in the literature is discussed. Also discussed are the consequences of magnetic fields and cloud-cloud shielding. The results illustrate how varying the individual column densities of the ionized clouds can reproduce the range of line ratios observed and strongly suggest that the emission-line nebulae are self-irradiated condensing regions at the centers of cooling flows.

  8. An Explanation of Remarkable Emission-line Profiles in Post-flare Coronal Rain

    NASA Astrophysics Data System (ADS)

    Lacatus, Daniela A.; Judge, Philip G.; Donea, Alina

    2017-06-01

    We study broad redshifted emission in chromospheric and transition region lines that appears to correspond to a form of post-flare coronal rain. Profiles of Mg ii, C ii, and Si iv lines were obtained using IRIS before, during, and after the X2.1 flare of 2015 March 11 (SOL2015-03-11T16:22). We analyze the profiles of the five transitions of Mg ii (the 3p-3s h and k transitions, and three lines belonging to the 3d-3p transitions). We use analytical methods to understand the unusual profiles, together with higher-resolution observational data of similar phenomena observed by Jing et al. The peculiar line ratios indicate anisotropic emission from the strands that have cross-strand line center optical depths (k line) of between 1 and 10. The lines are broadened by unresolved Alfvénic motions whose energy exceeds the radiation losses in the Mg ii lines by an order of magnitude. The decay of the line widths is accompanied by a decay in the brightness, suggesting a causal connection. If the plasma is ≲99% ionized, ion-neutral collisions can account for the dissipation; otherwise, a dynamical process seems necessary. Our work implies that the motions are initiated during the impulsive phase, to be dissipated as radiation over a period of an hour, predominantly by strong chromospheric lines. The coronal “rain” we observe is far more turbulent than most earlier reports have indicated, with implications for plasma heating mechanisms.

  9. On the accuracy of Black Hole Mass estimation from Broad Emission Lines

    NASA Astrophysics Data System (ADS)

    Mejia-Restrepo, Julian; Trakhtenbrot, Benny; Lira, Paulina; Netzer, Hagai; Capellupo, Daniel

    2016-08-01

    In this talk we compare single-epoch (SE) black hole mass (MBH) estimates based on low ionization (Hα, Hβ, and MgII) and high ionization (CIV) broad emission lines. We also examine the implications of different continuum modeling approaches in line width and MBH measurements. For this purpose we use a sample of 39 unobscured AGNs at z=1.55 selected to cover a large range in MBH (2.0dex) and L/Ledd (2.5dex) and observed by X-shooter. We find that using a local power-law continuum instead of a physically-motivated thin disk continuum leads to only slight underestimation of the FWHM of the lines and the associated MBH(FWHM). However, the line dispersion σ and associated MBH(σ) are strongly affected by the continuum placement providing less reliable mass estimates. We find that low ionization lines provides reliable virial MBH estimation. However, the CIV line is not reliable in the majority of the cases, indicating that the gas emitting this line may not be virialized. We find that Hα, Hβ show similar line widths and that FWHM(MgII) is about 30% narrower than FWHM(Hβ) . We test and confirm several recent suggestions to improve the accuracy in CIV-based mass estimates, relying on other UV emission lines. However, we find that such improvements do not help in reducing the scatter between CIV-based and Balmer-line-based mass estimates. This work has been recently accepted for publication in MNRAS.

  10. HST WFC3 Early Release Science: Emission-Line Galaxies from IR Grism Observations

    NASA Technical Reports Server (NTRS)

    Straughn, A. N.; Kuntschner, H.; Kuemmel, M.; Walsh, J. R.; Cohen, S. H.; Gardner, J. P.; Windhorst, R. A.; O'Connell, R. W.; Pirzkal, N.; Meurer, G.; hide

    2010-01-01

    We present grism spectra of emission line galaxies (ELGs) from 0.6-1.6 microns from the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST). These new infrared grism data augment previous optical Advanced Camera for Surveys G800L (0.6-0.95 micron) grism data in GOODS South, extending the wavelength coverage well past the G800L red cutoff. The ERS grism field was observed at a depth of 2 orbits per grism, yielding spectra of hundreds of faint objects, a subset of which are presented here. ELGs are studied via the Ha, [O III ], and [OII] emission lines detected in the redshift ranges 0.2 less than or equal to z less than or equal to 1.6, 1.2 less than or equal to z less than or equal to 2.4 and 2.0 less than or equal to z less than or equal to 3.6 respectively in the G102 (0.8-1.1 microns; R approximately 210) and C141 (1.1-1.6 microns; R approximately 130) grisms. The higher spectral resolution afforded by the WFC3 grisms also reveals emission lines not detectable with the G800L grism (e.g., [S II] and [S III] lines). From these relatively shallow observations, line luminosities, star formation rates, and grism spectroscopic redshifts are determined for a total of 25 ELGs to M(sub AB)(F098M) approximately 25 mag. The faintest source in our sample with a strong but unidentified emission line--is MAB(F098M)=26.9 mag. We also detect the expected trend of lower specific star formation rates for the highest mass galaxies in the sample, indicative of downsizing and discovered previously from large surveys. These results demonstrate the remarkable efficiency and capability of the WFC3 NIR grisms for measuring galaxy properties to faint magnitudes.

  11. Reverberation Modeling of the Broad Emission Line Region in NGC 5548

    NASA Astrophysics Data System (ADS)

    Bottorff, M. C.; Korista, K. T.; Shlosman, I.; Blandford, R. D.

    Long-term observations of broad-line region (BLR) in the Seyfert~1 galaxy NGC~5548 are analyzed and a critical comparison with the predictions of a hydromagnetically-driven outflow model of Emmering, Blandford and Shlosman is provided. This model is used to generate a time series of C~IV line profiles that have responded to a time varying continuum. We include cloud emission anisotropy, cloud obscuration, a CLOUDY-generated emissivity function and a narrow-line component which is added to the BLR component to generate the total line profiles. The model is driven with continuum input based on the monitoring campaigns of NGC~5548 reported in Clavel et al. and Korista et al., and the line strengths, profiles and lags are compared with the observations. The model is able to reproduce the basic features of CIV line variability in this active galactic nucleus, i.e., time evolution of the profile shape and strength of the C~IV emission line without varying the model parameters. The best fit model provides the effective size, the dominant geometry, the emissivity distribution and the 3D velocity field of the C~IV BLR and constrains the mass of the central black hole to about $3\\times 10^7\\ M_{\\odot}$. The inner part of the wind in NGC~5548 appears to be responsible for the anisotropically emitted CIV line, while its outer part remains dusty and molecular, thus having similar spectral characteristics to a molecular torus, although its dynamics is fundamentally different. The model predicts a differential response across the C~IV line profile, producing a red-side-first response in the relative velocity interval of $3,000-6,000 {\\rm km\\ s^{-1}}$ followed by the blue mid-wing and finally by the line core. Given that no adequate method in computing the errors for data lags and centroids exists in the literature, the {\\it data} cross-correlation function provides results which appear inconclusive, making any direct comparison with the model premature. Overall analysis

  12. Dynamics of Broad Emission-Line Region in NGC 5548: Hydromagnetic Wind Model versus Observations

    NASA Astrophysics Data System (ADS)

    Bottorff, Mark; Korista, Kirk T.; Shlosman, Isaac; Blandford, Roger D.

    1997-04-01

    We analyze the results of long-term observations of the broad-line region (BLR) in the Seyfert 1 galaxy NGC 5548 and provide a critical comparison with the predictions of a hydromagnetically driven outflow model of Emmering, Blandford, & Shlosman. We use this model to generate a time series of C IV line profiles that have responded to a time-varying continuum. Our modifications to the model include cloud emission anisotropy, cloud obscuration, a CLOUDY-generated emissivity function, and a narrow-line component which is added to the BLR component to generate the total line profiles. The model is driven with continuum input based on the monitoring campaigns of NGC 5548 reported in Clavel et al. and Korista et al., and the line strengths, profiles, and lags are compared with the observations. Our model is able to reproduce the basic features of C IV line variability in this active galactic nucleus, i.e., time evolution of the profile shape and strength of the C IV emission line without varying the model parameters. The best-fit model provides the effective size, the dominant geometry, the emissivity distribution, and the three-dimensional velocity field of the C IV BLR and constrains the mass of the central black hole to ~3 × 107 M⊙. The inner part of the wind in NGC 5548 appears to be responsible for the anisotropically emitted C IV line, while its outer part remains dusty and molecular, thus having similar spectral characteristics to a molecular torus, although its dynamics is fundamentally different. In addition, our model predicts a differential response across the C IV line profile, producing a red-side-first response in the relative velocity interval of 3000 km s-1 to 6000 km s-1 followed by the blue mid-wing and finally by the line core. Based on the comparison of data and model cross-correlation functions and one- and two-dimensional transfer functions, we find that the rotating outflow model is compatible with observations of the BLR in NGC 5548.

  13. STRONG FIELD EFFECTS ON EMISSION LINE PROFILES: KERR BLACK HOLES AND WARPED ACCRETION DISKS

    SciTech Connect

    Wang Yan; Li Xiangdong

    2012-01-10

    If an accretion disk around a black hole is illuminated by hard X-rays from non-thermal coronae, fluorescent iron lines will be emitted from the inner region of the accretion disk. The emission line profiles will show a variety of strong field effects, which may be used as a probe of the spin parameter of the black hole and the structure of the accretion disk. In this paper, we generalize the previous relativistic line profile models by including both the black hole spinning effects and the non-axisymmetries of warped accretion disks. Our results show different features from the conventional calculations for either a flat disk around a Kerr black hole or a warped disk around a Schwarzschild black hole by presenting, at the same time, multiple peaks, rather long red tails, and time variations of line profiles with the precession of the disk. We show disk images as seen by a distant observer, which are distorted by the strong gravity. Although we are primarily concerned with the iron K-shell lines in this paper, the calculation is general and is valid for any emission lines produced from a warped accretion disk around a black hole.

  14. Mg II Chromospheric Emission Line Bisectors Of HD39801 And Its Relation With The Activity Cycle

    NASA Astrophysics Data System (ADS)

    García García, Leonardo Enrique; Pérez Martínez, M. Isabel

    2016-07-01

    Betelgeuse is a cool star of spectral type M and luminosity class I. In the present work, the activity cycle of Betelgeuse was obtained from the integrated emission flux of the Mg II H and K lines, using more than 250 spectra taken from the International Ultraviolet Explorer (IUE) online database. Of which it was found, based on a Lomb Scargle periodogram, a cycle of 16 years, along with 2 sub-cycles with a period of the order of 0.60 and 0.65 years, which may be due to turbulence or possible stellar flares. In addition, an analysis of line asymmetry was made by means of the chromospheric emission line bisectors, due to the strong self-absorption observed in this lines, the blue and red wings were analyzed independently. In order to measure such asymmetry, a "line shift" was calculated, from which several cycles of variability were obtained from a Lomb Scargle periodogram, spanning from few months to 4 years. In the sense, the most significant cycle is about 0.44 and 0.33 years in the blue and red wing respectively. It is worth noting, that the rotation period of the star doesn't play an important role in the variability of the Mg II lines. This technique provides us with a new way to study activity cycles of evolved stars.

  15. Polarization of Line Emission from an Accretion Disk and Application to Arp 102B

    NASA Astrophysics Data System (ADS)

    Chen, Kaiyou; Halpern, Jules P.; Titarchuk, Lev G.

    1997-07-01

    We model the polarization properties of line emission from an accretion disk under a range of assumptions about the source function and electron-scattering optical depth τes. For small values of τes and modest viewing angles, polarization can be in excess of the Chandrasekhar result for τes = ∞. The polarization vector can be either parallel or perpendicular to the projected direction of the disk axis. The polarization properties of the double-peaked Hα emission line of the broad-line radio galaxy Arp 102B observed by Antonucci, Hurt, & Agol can be understood in terms of electron scattering and line broadening within the line-emitting region if τes is of order unity, and if the position angle of polarization is parallel to the projected disk axis. The required small τes is consistent with the hypothesis that the Balmer lines in Arp 102B are produced by photoionization of the disk atmosphere.

  16. A detailed study of the emission lines in the Seyfert 1 nucleus of M81

    NASA Astrophysics Data System (ADS)

    Filippenko, Alexei V.; Sargent, Wallace L. W.

    1988-01-01

    The authors present optical spectra of M81 having moderate resolution (1.6 - 4.5 Å) and exceptionally high signal-to-noise ratios. The broad component of Hα emission first noticed by Peimbert and Torres-Peimbert is easily visible, confirming that M81 harbors an active galactic nucleus (AGN) of the Seyfert 1 type. Prominent forbidden lines are also present. An absorption-line template galaxy, NGC 4339, is used to eliminate the starlight, revealing the pure emission-line spectrum of M81. A detailed analysis of the nuclear narrow-line region is given. It is shown that a wide range of densities is present, making the observed relative intensities consistent with photoionization by dilute, nonstellar radiation. The authors derive the mass of the central object in M81 (≡5×105M_sun;), under the assumption that the widths of the broad permitted lines are induced by gravity. It appears that there have been no changes in the strength of the broad Hα line during the past few years, even though the X-ray flux of M81 has been observed to vary substantially.

  17. Far-infrared emission lines of CO and OH in the Orion-KL molecular shock

    NASA Technical Reports Server (NTRS)

    Watson, D. M.; Genzel, R.; Townes, C. H.; Storey, J. W. V.

    1985-01-01

    Observations of far infrared rotational emission lines which arise in the shocked gas associted with Orion-Kl are presented, including detections of the CO J = 34 yields 33, J = 31 yields 30, J = 26 yields 25, and OH sup 2 PI sub (3/2) J sup P = 7/2(-) yields 5/2(+) emission lines, as well as improved measurements of the CO J = 22 yields 21 and OH sup 2 PI sub (3/2) J = 5/2 yields 3/2 lines. These lines are observed to have velocity widths of Del V approx. 20 to 30 km/sec, somewhat less than either the 2 micro H sub 2 lines or the high velocity plateau component of the millimeter wave CO lines seen in this object. An H sub 2 column density of aprox. 3 x 10 to the 21st power, a total mass of approx. 1 solar mass and characteristic temperature and density T approx. 750 K and approx. 2 x 10 to the 6th power per cu cm can be derived from the CO intensities. The density is too low by at least an order of magnitude for the observed infrared H sub 2 and far infrared CO emission to be accounted for by a purely hydrodynamic shock, and support is lent to hydromagnetic shock models. From the present measurements, the relative abundance of CO is estimated to be CO H sub 2 = 1.2 x .0001, corresponding to 20 percent of the cosmic abundance of C existing in the form of CO. The average relative abundance of OH in the shocked gas is O/H sub 2 or = 5 x 10 to the -7th power. An upper limit to the intensity of the HD J - 1 yields 0 line is used to derive an upper limit of tau or = 3 for the D/H relative abundance in the Orion cloud core.

  18. Far-infrared emission lines of CO and OH in the Orion-KL molecular shock

    NASA Technical Reports Server (NTRS)

    Watson, D. M.; Genzel, R.; Townes, C. H.; Storey, J. M. V.

    1985-01-01

    Observations of far infrared rotational emission lines which arise in the shocked gas associated with Orion-Kl are presented, including detections of the CO J = 34 yields 33, J = 31 yields 30, J = 26 yields 25, and OH sup 2 PI sub (3/2) J sup P = 7/2(-) yields 5/2(+) emission lines, as well as improved measurements of the CO J = 22 yields 21 and OH sup 2 PI sub (3/2) J = 5/2 yields 3/2 lines. These lines are observed to have velocity widths of Del V approx. 20 to 30 km/sec, somewhat less than either the 2 micro H sub 2 lines or the high velocity plateau component of the millimeter wave CO lines seen in this object. An H sub 2 column density of approx. 3 x 10 to the 21st power, a total mass of approx. 1 solar mass and characteristic temperature and density T approx. 750 K and approx. 2 x 10 to the 6th power per cu cm can be derived from the CO intensities. The density is too low by at least an order of magnitude for the observed infrared H sub 2 and far infrared CO emission to be accounted for by a purely hydrodynamic shock, and support is lent to hydromagnetic shock models. From the present measurements, the relative abundance of CO is estimated to be CO H sub 2 = 1.2 x .0001, corresponding to 20% of the cosmic abundance of C existing in the form of CO. The average relative abundance of OH in the shocked gas is O/H sub 2 or = 5 x 10 to the -7th power. An upper limit to the intensity of the HD J = 1 yields 0 line is used to derive an upper limit of tau or = 3 for the D/H relative abundance in the Orion cloud core.

  19. Oxygen emission line properties from analysis of MAVEN-IUVS Echellograms of the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Mayyasi, Majd A.; Clarke, John T.; Stewart, Ian; McClintock, William; Schneider, Nicholas M.; Jakosky, Bruce; IUVS Team

    2016-10-01

    The high resolution echelle mode of the Mars Atmosphere and Volatile Evolution (MAVEN) mission Imaging Ultraviolet Spectrograph (IUVS) instrument has been used to spectrally image the sunlit limb of Mars during the spacecraft periapse orbital segments. When multiple images are co-added over a few hours, there are detectable spectral emission features that have been identified to originate from atomic and molecular neutral species such as H, D, N, O, CO as well as from C+ ions. The echelle detector has a localized spectral resolution of ~0.008 Angstrom and is therefore capable of spectrally resolving the oxygen resonant triplet (130.217, 130.486 and 130.603 nm) and forbidden doublet (135.560 and 135.851 nm) emission lines. The brightness of each of these emission lines has been determined and will be compared with detected brightnesses of other species. The emission line integrated brightness ratios are being analyzed for insights into the abundance, excitation, and variability of oxygen in the martian atmosphere.

  20. emission-line stars in molecular clouds. II. The M 42 region

    NASA Astrophysics Data System (ADS)

    Pettersson, Bertil; Armond, Tina; Reipurth, Bo

    2014-10-01

    We present a deep survey of Hα emission-line stars in the M 42 region using wide-field objective prism films. A total of 1699 Hα emission-line stars were identified, of which 1025 were previously unknown, within an area of 5.̊5 × 5.̊5 centred on the Trapezium Cluster. We present Hα strength estimates, positions, and JHKs photometry extracted from 2MASS, and comparisons to previous surveys. The spatial distribution of the bulk of the stars follows the molecular cloud as seen in CO and these stars are likely to belong to the very young population of stars associated with the Orion Nebula Cluster. Additionally, there is a scattered population of Hα emission-line stars distributed all over the region surveyed, which may consist partly of foreground stars associated with the young NGC 1980 cluster, as well as some foreground and background dMe or Be stars. The present catalogue adds a large number of candidate low-mass young stars belonging to the Orion population, selected independently of their infrared excess or X-ray emission. Full Table 2 is only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/570/A30

  1. VizieR Online Data Catalog: Vatican Emission-line stars (Coyne+ 1974-1983)

    NASA Astrophysics Data System (ADS)

    Coyne, G. V.; Lee, T. A.; de Graeve, E.; Wisniewski, W.; Corbally, C.; Otten, L. B.; MacConnell, D. J.

    2008-03-01

    The survey represents a search for Hα emission-line stars, and was conducted with a 12{deg} objective prism on the Vatican Schmidt telescope. The Vatican Emission Stars (VES) survey covers the galactic plane (|b|<=5{deg}) between galactic longitudes 58 and 174{deg}. The catalog was re-examined by B. Skiff (Lowell Observatory), and tne VES stars were cross-identified with modern surveys: GSC (Cat. I/255), Tycho-2 (I/256), 2MASS (II/246), IRAS point source catalog (II/125), MSX6C (V/114), CMC14 (I/304), GSC-2.3 (I/305), UCAC2 (I/289). Cross-identifications are also supplied with HD/BD/GCVS names, and with Dearborn catalog of red stars (II/68). Many of the stars in the first four papers are not early-type emission-line stars, but instead M giants, where the sharp TiO bandhead at 6544{AA} was mistaken for H-{alpha} emission on the objective-prism plates. Based on the revision of paper V and a later list prepared by Jack MacConnell, a column identifies the "non H-alpha" stars explicitly. The links with the Dearborn, IRAS, and MSX catalogues help identify the red stars. These and other identifications and comments are given in the remarks at the end of each line, or in longer notes in a separate file, indicated by an asterisk (*) next to the star number. (2 data files).

  2. VizieR Online Data Catalog: Vatican Emission-line stars (Coyne+ 1974-1983)

    NASA Astrophysics Data System (ADS)

    Coyne, G. V.; Lee, T. A.; de Graeve, E.; Wisniewski, W.; Corbally, C.; Otten, L. B.; MacConnell, D. J.

    2009-10-01

    The survey represents a search for Hα emission-line stars, and was conducted with a 12{deg} objective prism on the Vatican Schmidt telescope. The Vatican Emission Stars (VES) survey covers the galactic plane (|b|<=5{deg}) between galactic longitudes 58 and 174{deg}. The catalog was re-examined by B. Skiff (Lowell Observatory), and tne VES stars were cross-identified with modern surveys: GSC (Cat. I/255), Tycho-2 (I/256), 2MASS (II/246), IRAS point source catalog (II/125), MSX6C (V/114), CMC14 (I/304), GSC-2.3 (I/305), UCAC2 (I/289). Cross-identifications are also supplied with HD/BD/GCVS names, and with Dearborn catalog of red stars (II/68). Many of the stars in the first four papers are not early-type emission-line stars, but instead M giants, where the sharp TiO bandhead at 6544{AA} was mistaken for H-{alpha} emission on the objective-prism plates. Based on the revision of paper V and a later list prepared by Jack MacConnell, a column identifies the "non H-alpha" stars explicitly. The links with the Dearborn, IRAS, and MSX catalogues help identify the red stars. These and other identifications and comments are given in the remarks at the end of each line, or in longer notes in a separate file, indicated by an asterisk (*) next to the star number. (3 data files).

  3. 2D-photochemical model for forbidden oxygen line emission for comets

    NASA Astrophysics Data System (ADS)

    Cessateur, G.; De Keyser, J.; Maggiolo, R.; Rubin, M.; Gronoff, G.; Gibbons, A.; Jehin, E.; Dhooghe, F.; Gunell, H.; Vaeck, N.; Loreau, J.

    2016-12-01

    Emissions at 577.7 nm (green line), 630 nm, and 636.4 nm (red-doublet) come from the deactivation of the O(1S) and O(1D) oxygen states. The photodissociation of H2O, CO and CO2 in the inner coma are responsible for the production of those oxygen states. This list of species had to be extended to include molecular oxygen since its in-situ detection by the Rosetta and Giotto missions. This contribution will present a 2D-photochemical model that calculates the number densities of the O(1S) and O(1D) oxygen states in the comae of various comets, taking the production, the loss and the transport mechanisms into account. For very active comets, e.g. 1P/Halley, a 1D model does not suffice since the solar UV flux is strongly absorbed resulting in an overestimation of the red-doublet and green lines emissions by a factor of 2. Even when assuming spherical symmetry of the neutral gas coma, the phase angle of the observation introduces asymmetries in the measured emission line ratios. Emission maps are deduced from our 2D-model, which can directly be compared to ground and/or in-situ observations.

  4. The SAMI Galaxy Survey: Publicly Available Spatially Resolved Emission Line Data Products

    NASA Astrophysics Data System (ADS)

    Medling, Anne; Green, Andrew W.; Ho, I.-Ting; Groves, Brent; Croom, Scott; SAMI Galaxy Survey Team

    2017-01-01

    The SAMI Galaxy Survey is collecting optical integral field spectroscopy of up to 3400 nearby (z<0.1) galaxies with a range of stellar masses and in a range of environments. The first public data release contains nearly 800 galaxies from the Galaxy And Mass Assembly (GAMA) Survey. In addition to releasing the reduced data cubes, we also provide emission line fits (flux and kinematic maps of strong emission lines including Halpha and Hbeta, [OII]3726,29, [OIII]4959,5007, [OI]6300, [NII]6548,83, and [SII]6716,31), extinction maps, star formation classification masks, and star formation rate maps. We give an overview of the data available for your favorite emission line science and present a few early science results. For example, a sample of edge-on disk galaxies show enhanced extraplanar emission related to SF-driven outflows, which are correlated with a bursty star formation history and higher star formation rate surface densities. Interestingly, the star formation rate surface densities of these wind hosts are 5-100 times lower than the canonical threshold for driving winds (0.1 MSun/yr/kpc2), indicating that galactic winds may be more important in normal star-forming galaxies than previously thought.

  5. The iron emission lines K α and K β in active galactic nuclei — A further piece of evidence for the Cerenkov line-like radiation

    NASA Astrophysics Data System (ADS)

    Liu, Dang-bo; Chen, Lei; Chen, Wen-ping; You, Jun-han

    2006-07-01

    It has been recently observed by XMM-Newton that besides the emission line of iron K α at 6.4 keV there also exists in the Seyfert 1 galaxy NGC 3783 the very intense emission line of iron K β at 7.0 keV. Moreover, the ratio of equivalent widths (EWs) of these two lines can hardly be interpreted with the traditional mechanism of "photoelectric absorption — fluorescence emission". By using the mechanism of Cerenkov line-like radiation proposed by YOU Jun-hian et al., the ratio of EW K α/EW K β may be reasonably interpreted by means of a detailed model theoretical computation. As shown by the results, the iron K lines in active galactic nuclei (AGNs) are formed not only by the fluorescence mechanism, but also by the Cerenkov line-like radiation. Both coexist in AGNs, with the latter playing the dominant role.

  6. Detection of an unidentified emission line in the stacked X-ray spectrum of galaxy clusters

    SciTech Connect

    Bulbul, Esra; Foster, Adam; Smith, Randall K.; Randall, Scott W.; Markevitch, Maxim; Loewenstein, Michael

    2014-07-01

    We detect a weak unidentified emission line at E = (3.55-3.57) ± 0.03 keV in a stacked XMM-Newton spectrum of 73 galaxy clusters spanning a redshift range 0.01-0.35. When the full sample is divided into three subsamples (Perseus, Centaurus+Ophiuchus+Coma, and all others), the line is seen at >3σ statistical significance in all three independent MOS spectra and the PN 'all others' spectrum. It is also detected in the Chandra spectra of the Perseus Cluster. However, it is very weak and located within 50-110 eV of several known lines. The detection is at the limit of the current instrument capabilities. We argue that there should be no atomic transitions in thermal plasma at this energy. An intriguing possibility is the decay of sterile neutrino, a long-sought dark matter particle candidate. Assuming that all dark matter is in sterile neutrinos with m{sub s} = 2E = 7.1 keV, our detection corresponds to a neutrino decay rate consistent with previous upper limits. However, based on the cluster masses and distances, the line in Perseus is much brighter than expected in this model, significantly deviating from other subsamples. This appears to be because of an anomalously bright line at E = 3.62 keV in Perseus, which could be an Ar XVII dielectronic recombination line, although its emissivity would have to be 30 times the expected value and physically difficult to understand. Another alternative is the above anomaly in the Ar line combined with the nearby 3.51 keV K line also exceeding expectation by a factor of 10-20. Confirmation with Astro-H will be critical to determine the nature of this new line.

  7. IUE observations of the Henize-Carlson sample of peculiar emission line supergiants: The galactic analogs of the Magellanic Zoo

    NASA Technical Reports Server (NTRS)

    Shore, Steven N.; Brown, Douglas N.; Sanduleak, N.

    1986-01-01

    Some 15 stars from the Carlson-Henize survey of southern peculiar emission line stars were studied. From both the optical and UV spectra, they appear to be galactic counterparts of the most extreme early-type emission line supergiants of the Magellanic Clouds.

  8. IUE observations of the Henize-Carlson sample of peculiar emission line supergiants: The galactic analogs of the Magellanic Zoo

    NASA Technical Reports Server (NTRS)

    Shore, Steven N.; Brown, Douglas N.; Sanduleak, N.

    1986-01-01

    Some 15 stars from the Carlson-Henize survey of southern peculiar emission line stars were studied. From both the optical and UV spectra, they appear to be galactic counterparts of the most extreme early-type emission line supergiants of the Magellanic Clouds.

  9. FIRST DETECTION OF NEAR-INFRARED LINE EMISSION FROM ORGANICS IN YOUNG CIRCUMSTELLAR DISKS

    SciTech Connect

    Mandell, Avi M.; Mumma, Michael J.; Villanueva, Geronimo; Bast, Jeanette; Van Dishoeck, Ewine F.; Blake, Geoffrey A.; Salyk, Colette

    2012-03-10

    We present an analysis of high-resolution spectroscopy of several bright T Tauri stars using the CRIRES spectrograph on the Very Large Telescope and NIRSPEC spectrograph on the Keck Telescope, revealing the first detections of emission from HCN and C{sub 2}H{sub 2} in circumstellar disks at near-infrared wavelengths. Using advanced data reduction techniques, we achieve a dynamic range with respect to the disk continuum of {approx}500 at 3 {mu}m, revealing multiple emission features of H{sub 2}O, OH, HCN, and C{sub 2}H{sub 2}. We also present stringent upper limits for two other molecules thought to be abundant in the inner disk, CH{sub 4} and NH{sub 3}. Line profiles for the different detected molecules are broad but centrally peaked in most cases, even for disks with previously determined inclinations of greater than 20 Degree-Sign , suggesting that the emission has both a Keplerian and non-Keplerian component as observed previously for CO emission. We apply two different modeling strategies to constrain the molecular abundances and temperatures: we use a simplified single-temperature local thermal equilibrium (LTE) slab model with a Gaussian line profile to make line identifications and determine a best-fit temperature and initial abundance ratios, and we compare these values with constraints derived from a detailed disk radiative transfer model assuming LTE excitation but utilizing a realistic temperature and density structure. Abundance ratios from both sets of models are consistent with each other and consistent with expected values from theoretical chemical models, and analysis of the line shapes suggests that the molecular emission originates from within a narrow region in the inner disk (R < 1 AU).

  10. Evolution of Emission Line Galaxies from z<0.5 to the present

    NASA Astrophysics Data System (ADS)

    Horowitz, I. K.; Schmidt, M.; Schneider, D. P.

    1992-12-01

    A comparison of the luminosity functions of two samples of emission line galaxies is to be made so as to determine the extent to which evolutionary effects play a role in these objects from z<0.5 to the present. The distant sample of objects were taken from the 4-Shooter transit surveys of Schmidt, Schneider and Gunn (hereafter SSG). It consists of 370 galaxies whose inclusion was based on the detection of either the Hβ lambda 4861 or the [OIII]lambda lambda 4959,5007 emission line. The nearby sample was taken from the CfA Northern Sky Redshift Survey (Davis, et.al., 1983). From the work of Burg (1987), a subset of 81 galaxies with strong [OIII] emission (EW>25 Angstroms) has been selected. An additional 26 Seyfert galaxies from Edelson (1987) were added to that list. This group of 107 CfA galaxies represented an initial sample to be observed using the Echelle Spectrograph on the 1.5m Oscar Meyer telescope at Palomar Observatory. The spectrograph was operated in a low-resolution, long slit (360'') mode, covering the range from 4350 Angstroms to 7200 Angstroms. Spectra were taken along the major and minor axes of each CfA galaxy, and were modeled to determine how each galaxy would appear in the transit survey as a function of redshift. Having determined the maximum observable redshift for each CfA galaxy, based on the transit survey criteria, a luminosity function is calculated. This is then compared to the observed luminosity function of the sample of distant emission line galaxies, and, upon completion of this work, a statement will be made on the effects of evolution on various sub-classes of emission line galaxies.

  11. Molecular Line Emission Towards High-Mass Clumps: The MALT90 Catalogue

    NASA Astrophysics Data System (ADS)

    Rathborne, J. M.; Whitaker, J. S.; Jackson, J. M.; Foster, J. B.; Contreras, Y.; Stephens, I. W.; Guzmán, A. E.; Longmore, S. N.; Sanhueza, P.; Schuller, F.; Wyrowski, F.; Urquhart, J. S.

    2016-07-01

    The Millimetre Astronomy Legacy Team 90 GHz survey aims to characterise the physical and chemical evolution of high-mass clumps. Recently completed, it mapped 90 GHz line emission towards 3 246 high-mass clumps identified from the ATLASGAL 870 μm Galactic plane survey. By utilising the broad frequency coverage of the Mopra telescope's spectrometer, maps in 16 different emission lines were simultaneously obtained. Here, we describe the first catalogue of the detected line emission, generated by Gaussian profile fitting to spectra extracted towards each clumps' 870 μm dust continuum peak. Synthetic spectra show that the catalogue has a completeness of > 95%, a probability of a false-positive detection of < 0.3%, and a relative uncertainty in the measured quantities of < 20% over the range of detection criteria. The detection rates are highest for the (1-0) transitions of HCO+, HNC, N2H+, and HCN (~77-89%). Almost all clumps (~95%) are detected in at least one of the molecular transitions, just over half of the clumps (~53%) are detected in four or more of the transitions, while only one clump is detected in 13 transitions. We find several striking trends in the ensemble of properties for the different molecular transitions when plotted as a function of the clumps' evolutionary state as estimated from Spitzer mid-IR images, including (1) HNC is relatively brighter in colder, less evolved clumps than those that show active star formation, (2) N2H+ is relatively brighter in the earlier stages, (3) that the observed optical depth decreases as the clumps evolve, and (4) the optically thickest HCO+ emission shows a `blue-red asymmetry' indicating overall collapse that monotonically decreases as the clumps evolve. This catalogue represents the largest compiled database of line emission towards high-mass clumps and is a valuable data set for detailed studies of these objects.

  12. Spectroscopically and spatially resolved optical line emission in the Superantennae (IRAS 19254-7245)

    NASA Astrophysics Data System (ADS)

    Bendo, George J.; Clements, David L.; Khan, Sophia A.

    2009-10-01

    We present Visible Multi-Object Spectrograph integral-field spectroscopic observations of the ultraluminous infrared galaxy (ULIRG) pair IRAS 19254-7245 (the Superantennae). We resolve Hα, [NII], [OI] and [SII] emission both spatially and spectroscopically, and separate the emission into multiple velocity components. We identify spectral line emission characteristic of star formation associated with both galaxies, broad spectral line emission from the nucleus of the southern progenitor and potential outflows with shock-excited spectral features near both nuclei. We estimate that <~10 per cent of the 24 μm flux density originates from star formation, implying that most of the 24 μm emission originates from the active galactic nuclei in the southern nucleus. We also measure a gas consumption time of ~1 Gyr, which is consistent with other measurements of ULIRGs. Based on observations collected at the European Organization for Astronomical Research in the Southern hemisphere, Chile [080.B-0085]. E-mail: g.bendo@imperial.ac.uk ‡ ALMA fellow.

  13. X-rays from emission-line stars in the Herbig-Haro 1 region

    NASA Technical Reports Server (NTRS)

    Pravdo, Steven H.; Angelini, Lorella

    1993-01-01

    We have observed the region in Orion containing Herbig-Haro 1 as well as a number of young, active stars. This observation shows a similar X-ray morphology to that in the first X-ray imaging observation about 10 years ago. The ROSAT High Resolution Instrument with its approximately arcsecond spatial resolution allows us in most cases to make definite optical identifications of the 0.1-2.4 keV X-ray sources. New identifications with emission-line stars are made, and prior identifications using lower resolution observations are confirmed or corrected. The X-ray emission previously detected from the vicinity of HH-1 is not associated with HH-1 but with a known T Tauri star. The observed relationships among X-ray, optical line, and infrared excess emission do not simply fall into the suggested classifications for T Tauri or T Tauri-like stars. This could be an indication of another X-ray emission region such as accretion disks that add to the emission from the stellar atmospheres.

  14. HST/ACS Emission Line Snapshots of nearby 3CR Radio Galaxies

    NASA Astrophysics Data System (ADS)

    Tremblay, Grant; Sparks, W. B.; Chiaberge, M.; Baum, S. A.; Allen, M. G.; Axon, D. J.; Capetti, A.; Floyd, D. J. E.; Macchetto, F. D.; Miley, G. K.; O'Dea, C. P.; Perlman, E. S.; Quillen, A. C.

    2008-03-01

    We present the results of a new HST/ACS snapshot program in which we have obtained emission line images of nearby (z < 0.3) 3CR radio source counterparts at low- and high- excitation. Prior to ACS failure data were acquired successfully for 20 such objects, a sample consisting of both low-power FR I and classical high-power FR II radio galaxies. While only a subset of our initially proposed sample was observed, the newly reduced data we do have are excellent and will serve as an enhancement to an already superb dataset. In future papers, we will use these data to probe fundamental relationships between warm optical line-emitting gas, radio source structure (jets and lobes) and X-ray coronal halos. We will combine our existing UV images with new emission line images to establish quantitative star formation characteristics and their relation to dust and merger scenarios. Through the use of emission-line excitation maps, we will test theories on ionization beam patterns and luminosities from active nuclei, as well as seek areas of jet induced star formation. The resulting database will be an invaluable resource to the astronomical community for years to come.

  15. 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.

  16. Line emission of sodium and hydroxyl radicals in single-bubble sonoluminescence.

    PubMed

    Schneider, Julia; Pflieger, Rachel; Nikitenko, Sergey I; Shchukin, Dmitry; Möhwald, Helmuth

    2011-01-20

    Spectroscopic studies of single-bubble sonoluminescence (SBSL) in water and aqueous sodium chloride solutions with a defined concentration of argon were performed as a function of the driving acoustic pressure. The broad-band continuum ranging from 200 to 700 nm is characterized by fits using Planck's law of blackbody radiation. The obtained blackbody temperatures are in the range of 10(4) K and are revealed to be independent of the presence of a salt and the acoustic pressure, whereas the SL intensity increases by a factor of more than 10 within the studied acoustic pressure range. The different trends followed by SL intensity and blackbody temperatures question the blackbody model. In solutions with 70 mbar of argon, line emissions of OH(•) radicals and Na* are observed. The shape of the OH(•) radical emission spectrum is very similar to that in MBSL spectra, indicating the strong similarity of intrabubble conditions. An increase of the acoustic pressure causes the continuum to overlap the lines until they become indistinguishable. The emission line of Na* in NaCl is observed only at high NaCl concentrations. When sodium dodecylsulfate is used a pronounced Na* line is already observed in a 1 mM solution thanks to enrichment of sodium ions at the interface. The results presented in this work reveal the strong similarity of SBSL and MBSL under certain experimental conditions.

  17. A New Hα Emission-line Survey in the Orion Nebula Cluster

    NASA Astrophysics Data System (ADS)

    Szegedi-Elek, E.; Kun, M.; Reipurth, B.; Pál, A.; Balázs, L. G.; Willman, M.

    2013-10-01

    We present results from an Hα emission line survey in a 1 deg2 area centered on the Orion Nebula Cluster, obtained with the Wide Field Grism Spectrograph 2 on the 2.2 m telescope of the University of Hawaii. We identified 587 stars with Hα emission, 99 of which, located mainly in the outer regions of the observed area, have not appeared in previous Hα surveys. We determined the equivalent width (EW) of the line and, based on this, classified 372 stars as classical T Tauri stars (CTTSs) and 187 as weak-line T Tauri stars (WTTSs). Simultaneous r', i' photometry indicates a limiting magnitude of r' ~ 20 mag, but the sample is incomplete at r' > 17 mag. The surface distribution of the Hα emission stars reveals a clustered population and a dispersed population, the former consisting of younger and more massive young stars than the latter. Comparison of the derived EWs with those found in the literature indicates variability of the Hα line. We found that the typical amplitudes of the variability are not greater than a factor of two to three in most cases. We identified a subgroup of low-EW stars with infrared signatures indicative of optically thick accretion disks. We studied the correlations between the EW and other properties of the stars. Based on literature data, we examined several properties of our CTTS and WTTS subsamples and found significant differences in mid-infrared color indices, average rotational periods, and spectral energy distribution characteristics of the subsamples.

  18. Time Variable Broad Line Emission in NGC 4203: Evidence for Stellar Contrails

    NASA Astrophysics Data System (ADS)

    Devereux, Nicholas A.

    2012-01-01

    Dual epoch spectroscopy of the lenticular galaxy, NGC 4203, obtained with the Hubble Space Telescope has revealed that the double-peaked component of the broad Hα emission line is time variable, increasing by a factor of 2.2 in brightness between 1999 and 2010. Modeling the gas distribution responsible for the double-peaked profiles indicates that a ring is a more appropriate description than a disk and most likely represents the contrail of a red supergiant star that is being tidally disrupted at a distance of 1500 AU from the central black hole. There is also a bright core of broad Hα line emission that is not time variable and identified with a large scale inflow from an outer radius 1 pc. If the gas number density is ≥ 106 cm-3, as suggested by the absence of similarly broad [O I] and [O III] emission lines, then the steady state inflow rate is 2 × 10-2 M⊙/yr which exceeds the inflow requirement to explain the X-ray luminosity in terms of radiatively inefficient accretion by a factor of 6. The central AGN is unable to sustain ionization of the broad line region, the discrepancy is particularly acute in 2010 when the broad Hα emission line is dominated by the contrail of the in-falling supergiant star. However, ram pressure shock ionization produced by the interaction of the in-falling supergiant with the ambient interstellar medium may help alleviate the ionizing deficit by generating a mechanical source of ionization supplementing the photoionization provided by the AGN. Support for Program number HST AR-11752.01-A was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, incorporated, under NASA contract NAS5-26555.

  19. 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.

  20. CO Line Emission and Absorption from the HL Tauri Disk-Where Is All the Dust?

    NASA Astrophysics Data System (ADS)

    Brittain, Sean D.; Rettig, Terrence W.; Simon, Theodore; Kulesa, Craig

    2005-06-01

    We present high-resolution infrared spectra of HL Tau, a heavily embedded young star. The spectra exhibit broad emission lines of 12CO gas-phase molecules, as well as narrow absorption lines of 12CO, 13CO, and C18O. The broad emission lines of vibrationally excited 12CO are dominated by the hot (T~1500 K) inner disk. The narrow absorption lines of CO are found to originate from the circumstellar gas at a temperature of ~100 K. The 12CO column density for this cooler material [(7.5+/-0.2)×1018 cm-2] indicates a large column of absorbing gas along the line of sight. In dense interstellar clouds, this column density of CO gas is associated with AV~52 mag. However, the extinction toward this source (AV~23) suggests that there is less dust along the line of sight than inferred from the CO absorption data. We discuss three possibilities for the apparent paucity of dust along the line of sight through the flared disk: (1) the dust extinction has been underestimated because of differences in circumstellar grain properties, such as grain agglomeration; (2) the effect of scattering has been underestimated and the actual extinction is much higher; or (3) the line of sight through the disk is probing a gas-rich, dust-depleted region, possibly due to the stratification of gas and dust in a preplanetary disk. Through the analysis of hot rovibrational 12CO line emission, we place strong constraints on grain growth and thermal infrared dust opacity, and separately constrain the enhancement of carbon-bearing species in the neighboring molecular envelope. The physical stratification of gas and dust in the HL Tau disk remains a viable explanation for the anomalous gas-to-dust ratio seen in this system. The measured radial velocity dispersion in the outer disk is consistent with the thermal line widths of the absorption lines, leaving only a small turbulent component to provide gas-dust mixing. The data presented herein were obtained at the W. M. Keck Observatory, which is operated

  1. Carbon and oxygen X-ray line emission from the interstellar medium

    NASA Technical Reports Server (NTRS)

    Schnopper, H. W.; Delvaille, J. P.; Rocchia, R.; Blondel, C.; Cheron, C.; Christy, J. C.; Ducros, R.; Koch, L.; Rothenflug, R.

    1982-01-01

    A soft X-ray, 0.3-1.0 keV spectrum from a 1 sr region which includes a portion of the North Polar Spur, obtained by three rocketborne lithium-drifted silicon detectors, shows the C V, C VI, O VII and O VIII emission lines. The spectrum is well fitted by a two-component, modified Kato (1976) model, where the coronal emission is in collisional equilibrium, with interstellar medium and North Polar Spur temperatures of 1.1 and 3.8 million K, respectively.

  2. Carbon and oxygen X-ray line emission from the interstellar medium

    NASA Technical Reports Server (NTRS)

    Schnopper, H. W.; Delvaille, J. P.; Rocchia, R.; Blondel, C.; Cheron, C.; Christy, J. C.; Ducros, R.; Koch, L.; Rothenflug, R.

    1982-01-01

    A soft X-ray, 0.3-1.0 keV spectrum from a 1 sr region which includes a portion of the North Polar Spur, obtained by three rocketborne lithium-drifted silicon detectors, shows the C V, C VI, O VII and O VIII emission lines. The spectrum is well fitted by a two-component, modified Kato (1976) model, where the coronal emission is in collisional equilibrium, with interstellar medium and North Polar Spur temperatures of 1.1 and 3.8 million K, respectively.

  3. Excitation wavelength dependence of water-window line emissions from boron-nitride laser-produced plasmas

    SciTech Connect

    Crank, M.; Harilal, S. S.; Hassan, S. M.; Hassanein, A.

    2012-02-01

    We investigated the effects of laser excitation wavelength on water-window emission lines of laser-produced boron-nitride plasmas. Plasmas are produced by focusing 1064 nm and harmonically generated 532 and 266 nm radiation from a Nd:YAG laser on BN target in vacuum. Soft x-ray emission lines in the water-window region are recorded using a grazing-incidence spectrograph. Filtered photodiodes are used to obtain complementary data for water-window emission intensity and angular dependence. Spectral emission intensity changes in nitrogen Ly-{alpha} and He-{alpha} are used to show how laser wavelength affects emission. Our results show that the relative intensity of spectral lines is laser wavelength dependent, with the ratio of Ly-{alpha} to He-{alpha} emission intensity decreasing as laser wavelength is shortened. Filtered photodiode measurements of angular dependence showed that 266 and 532 nm laser wavelengths produce uniform emission.

  4. Observations of argon emission lines used for fluorine atom actinometry in low power rf discharges

    NASA Astrophysics Data System (ADS)

    Savas, S. E.

    1986-04-01

    Anomalous power and frequency dependences of some argon emission lines are observed in a low power rf discharge in a 2% admixture of argon in CF4. Frequency ranges from 0.12 to 13.56 MHz for pressures of 25 and 50 mTorr and 20 W power to the plasma. Power and frequency dependences of the 7504 Å line differ from those for the 6416 Å, 6871 Å, and 7126 Å lines. These differences and argon excitation cross sections are used to examine the validity of actinometry assumptions. The 6871 Å or 6416 Å lines work better under these conditions as actinometer references, while the 7504 Å seems preferable for etch plasmas.

  5. Model for interpreting Doppler broadened optical line emission measurements on axially symmetric plasma

    NASA Technical Reports Server (NTRS)

    Englert, G. W.; Patch, R. W.; Reinmann, J. J.

    1978-01-01

    A plasma model, previously developed to interpret neutral-particle analyzer measurements on E x B heating devices, is adapted to analyze Doppler broadened charge-exchange-neutral lines measured by an optical monochromator. Comparison of theoretical with experimental results indicates that azimuthal drift as well as cyclotron motion are quite influential in determining line shapes and widths, and thus important in temperature determination, even when the monochromator line of sight is intersecting the plasma axis of symmetry. At this central sighting position, however, results are quite insensitive to radial ion density distribution when time lag between the charge-exchange-excitation events and emission is neglected. Line shapes and widths obtained by sighting across chords of plasma at various distances from the plasma axis of symmetry indicate a strong dependence on time lag.

  6. Emission line spectra of S VII ? S XIV in the 20 ? 75 ? wavelength region

    SciTech Connect

    Lepson, J K; Beiersdorfer, P; Behar, E; Kahn, S M

    2004-08-06

    As part of a larger project to complete a comprehensive catalogue of astrophysically relevant emission lines in support of new-generation X-ray observatories using the Lawrence Livermore electron beam ion traps EBIT-I and EBIT-II, the authors present observations of sulfur lines in the soft X-ray and extreme ultraviolet regions. The database includes wavelength measurements with standard errors, relative intensities, and line assignments for 127 transitions of S VII through S XIV between 20 and 75 {angstrom}. The experimental data are complemented with a full set of calculations using the Hebrew University Lawrence Livermore Atomic Code (HULLAC). A comparison of the laboratory data with Chandra measurements of Procyon allows them to identify S VII-S XI lines.

  7. Orbital modulation of X-ray emission lines in Cygnus X-3

    NASA Astrophysics Data System (ADS)

    Vilhu, O.; Hakala, P.; Hannikainen, D. C.; McCollough, M.; Koljonen, K.

    2009-07-01

    Aims: We address the problem where the X-ray emission lines are formed and investigate orbital dynamics using Chandra HETG observations, photoionizing calculations and numerical wind-particle simulations. The aims were to set constraints on the masses of the components of this close binary system consisting of a Wolf-Rayet (WR) star and a compact component and to investigate the nature of the latter (neutron star or black hole). The goal was also to investigate P Cygni signatures in line profiles. Methods: The observed Si xiv (6.185 Å) and S xvi (4.733 Å) line profiles at four orbital phases were fitted with P Cygni-type profiles consisting of an emission and a blue-shifted absorption component. Numerical models were constructed using photoionizing calculations and particle simulations. In the models, the emission originates in the photoionized wind of the WR companion illuminated by a hybrid source: the X-ray radiation of the compact star and the photospheric EUV-radiation from the WR star. Results: Spectral lines with moderate excitation (such as Si xiv and S xvi) arise in the photoionized wind. The emission component exhibits maximum blue-shift at phase 0.5 (when the compact star is in front), while the velocity of the absorption component is constant (around -900 km s-1). Both components, like the continuum flux, have intensity maxima around phase 0.5. The simulated Fe xxvi Lyα line (1.78 Å, H-like) from the wind is weak compared to the observed one. We suggest that it originates in the vicinity of the compact star, with a maximum blue shift at phase 0.25 (compact star approaching). By combining the mass function derived with that from the infrared He i absorption (arising from the WR companion), we constrain the masses and the inclination of the system. Conclusions: The Si xiv and S xvi lines and their radial velocity curves can be understood in the framework of a photoionized wind involving a hybrid ionizer. Constraints on the compact star mass and

  8. Mapping low- and high-density clouds in astrophysical nebulae by imaging forbidden line emission

    NASA Astrophysics Data System (ADS)

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

    2009-06-01

    Emission line ratios have been essential for determining physical parameters such as gas temperature and density in astrophysical gaseous nebulae. With the advent of panoramic spectroscopic devices, images of regions with emission lines related to these physical parameters can, in principle, also be produced. We show that, with observations from modern instruments, it is possible to transform images taken from density-sensitive forbidden lines into images of emission from high- and low-density clouds by applying a transformation matrix. In order to achieve this, images of the pairs of density-sensitive lines as well as the adjacent continuum have to be observed and combined. We have computed the critical densities for a series of pairs of lines in the infrared, optical, ultraviolet and X-rays bands, and calculated the pair line intensity ratios in the high- and low-density limit using a four- and five-level atom approximation. In order to illustrate the method, we applied it to Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (GMOS-IFU) data of two galactic nuclei. We conclude that this method provides new information of astrophysical interest, especially for mapping low- and high-density clouds; for this reason, we call it `the ld/hd imaging method'. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States); the Science and Technology Facilities Council (United Kingdom); the National Research Council (Canada), CONICYT (Chile); the Australian Research Council (Australia); Ministério da Ciência e Tecnologia (Brazil) and Secretaria de Ciencia y Tecnologia (Argentina). E-mail: steiner@astro.iag.usp.br

  9. Origin of the Galactic Diffuse X-Ray Emission: Iron K-shell Line Diagnostics

    NASA Astrophysics Data System (ADS)

    Nobukawa, Masayoshi; Uchiyama, Hideki; Nobukawa, Kumiko K.; Yamauchi, Shigeo; Koyama, Katsuji

    2016-12-01

    This paper reports detailed K-shell line profiles of iron (Fe) and nickel (Ni) of the Galactic Center X-ray Emission (GCXE), Galactic Bulge X-ray Emission (GBXE), Galactic Ridge X-ray Emission (GRXE), magnetic Cataclysmic Variables (mCVs), non-magnetic Cataclysmic Variables (non-mCVs), and coronally Active Binaries (ABs). For the study of the origin of the GCXE, GBXE, and GRXE, the spectral analysis is focused on equivalent widths of the Fe i-Kα, Fe xxv-Heα, and Fe xxvi-Lyα lines. The global spectrum of the GBXE is reproduced by a combination of the mCVs, non-mCVs, and ABs spectra. On the other hand, the GRXE spectrum shows significant data excesses at the Fe i-Kα and Fe xxv-Heα line energies. This means that additional components other than mCVs, non-mCVs, and ABs are required, which have symbiotic phenomena of cold gas and very high-temperature plasma. The GCXE spectrum shows larger excesses than those found in the GRXE spectrum at all the K-shell lines of iron and nickel. Among them the largest ones are the Fe i-Kα, Fe xxv-Heα, Fe xxvi-Lyα, and Fe xxvi-Lyβ lines. Together with the fact that the scale heights of the Fe i-Kα, Fe xxv-Heα, and Fe xxvi-Lyα lines are similar to that of the central molecular zone (CMZ), the excess components would be related to high-energy activity in the extreme envelopment of the CMZ.

  10. Shocks and Spatially Offset Active Galactic Nuclei Produce Velocity Offsets in Emission Lines

    NASA Astrophysics Data System (ADS)

    Comerford, Julia M.; Barrows, R. Scott; Greene, Jenny E.; Pooley, David

    2017-09-01

    While 2% of active galactic nuclei (AGNs) exhibit narrow emission lines with line-of-sight velocities that are significantly offset from the velocity of the host galaxy’s stars, the nature of these velocity offsets is unknown. We investigate this question with Chandra/ACIS and Hubble Space Telescope/Wide Field Camera 3 observations of seven velocity-offset AGNs at z< 0.12; all seven galaxies have a central AGN, but a peak in emission that is spatially offset by line flux ratios of the offset AGN are consistent with pure photoionization, while the optical line flux ratios of our sample are consistent with contributions from photoionization and shocks. We conclude that these optical line flux ratios could be efficient for separating velocity-offset AGNs into subgroups of offset AGNs—which are important for studies of AGN fueling in galaxy mergers—and central AGNs with shocks, where the outflows are biased toward the most energetic outflows that are the strongest drivers of feedback.

  11. Emission Lines of Fe XI - XIII in the Extreme Ultraviolet Region

    NASA Astrophysics Data System (ADS)

    Lepson, Jaan; Beiersdorfer, Peter; Liedahl, Duane; Desai, Priya; Brickhouse, Nancy; Dupree, Andrea; Kahn, Steven

    2009-05-01

    Iron is one of the most abundant heavy elements in extreme ultraviolet spectra of astrophysical and laboratory plasmas, and its various ions radiate profusely in the extreme ultraviolet (EUV) wavelength band. Iron emission in the EUV provides important d iagnostic tools for such properties as plasma temperature and density, and perhaps even magnetic field strength. Despite its importance to astrophysics and magnetic fusion, knowledge of the EUV spectrum of iron is incomplete. Identification of iron emis sion lines is hampered by the paucity of accurate laboratory measurements and the uncertainty of even the best atomic models. As part of a project to measure and compile emission line data in the EUV, we present here spectra and lines of Fe XI - XIII recorded on the Livermore EBIT-II electron beam ion trap in the 50 - 120 åregion. We measured line positions to 0.02 åand relative intensities with an accuracy of one part in twenty. Many new lines are identified and added to the available databa ses. Part of 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 was supported by NASA's Astronomy and Physics Research and Analysis Program under Con t ract NNH07AF811.

  12. Detection and Characterisation of H-{alpha} Emission Lines from Gaia BP/RP Spectra

    SciTech Connect

    Jaenes, Juergen; Laur, Sven; Kolka, Indrek

    2008-12-05

    The Gaia probe, set to launch in 2011, will measure an estimated billion astronomical objects, producing an enormous amount of data. One of the data analysis tasks will be the identification and classification of measured objects. A vast majority of them will be 'ordinary' stars from our Galaxy but a certain percentage will belong to 'peculiar' objects. We are interested in detecting emission line stars (ELS). The characteristic feature of most ELS is the presence of a H-{alpha} emission line in their spectra. In the case of Gaia measurements, the influence of this line could be detected in low resolution prismatic spectra which will be recorded both in blue (BP) and red (RP) spectral region. In this work, we compare different algorithms for detecting and characterising H-{alpha} lines in Gaia spectra. These include a simple, integrated flux ratio-based algorithm and several machine learning algorithms, such as neural networks, support vector machines and support vector regression. We study line detection both from single-transit and over-sampled end-of-mission data.

  13. LZIFU: an emission-line fitting toolkit for integral field spectroscopy data

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Medling, Anne M.; Groves, Brent; Rich, Jeffrey A.; Rupke, David S. N.; Hampton, Elise; Kewley, Lisa J.; Bland-Hawthorn, Joss; Croom, Scott M.; Richards, Samuel; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.

    2016-09-01

    We present lzifu (LaZy-IFU), an idl toolkit for fitting multiple emission lines simultaneously in integral field spectroscopy (IFS) data. lzifu is useful for the investigation of the dynamical, physical and chemical properties of gas in galaxies. lzifu has already been applied to many world-class IFS instruments and large IFS surveys, including the Wide Field Spectrograph, the new Multi Unit Spectroscopic Explorer (MUSE), the Calar Alto Legacy Integral Field Area (CALIFA) survey, the Sydney-Australian-astronomical-observatory Multi-object Integral-field spectrograph (SAMI) Galaxy Survey. Here we describe in detail the structure of the toolkit, and how the line fluxes and flux uncertainties are determined, including the possibility of having multiple distinct kinematic components. We quantify the performance of lzifu, demonstrating its accuracy and robustness. We also show examples of applying lzifu to CALIFA and SAMI data to construct emission line and kinematic maps, and investigate complex, skewed line profiles presented in IFS data. The code is made available to the astronomy community through github. lzifu will be further developed over time to other IFS instruments, and to provide even more accurate line and uncertainty estimates.

  14. Gas Excitation in ULIRGs: Maps of Diagnostic Emission-line Ratios in Space and Velocity

    NASA Astrophysics Data System (ADS)

    Soto, Kurt T.; Martin, Crystal L.

    2012-11-01

    Emission-line spectra extracted at multiple locations across 39 ultraluminous infrared galaxies have been compiled into a spectrophotometric atlas. Line profiles of Hα, [N II], [S II], [O I], Hβ, 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. The data presented herein were 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 the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  15. BROAD Hβ EMISSION-LINE VARIABILITY IN A SAMPLE OF 102 LOCAL ACTIVE GALAXIES

    SciTech Connect

    Runco, Jordan N.; Cosens, Maren; Bennert, Vardha N.; Scott, Bryan; Komossa, S.; Malkan, Matthew A.; Treu, Tommaso; Lazarova, Mariana S.; Auger, Matthew W.; Park, Daeseong E-mail: mcosens@calpoly.edu E-mail: malkan@astro.ucla.edu E-mail: lazarovam2@unk.edu E-mail: daeseongpark@kasi.re.kr

    2016-04-10

    A sample of 102 local (0.02 ≤ z ≤ 0.1) Seyfert galaxies with black hole masses M{sub BH} > 10{sup 7}M{sub ⊙} was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M{sub BH} and host galaxy properties. We study profile changes of the broad Hβ emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad Hβ emission line is of particular interest, not only because it is used to estimate M{sub BH}, but also because its strength and width are used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (∼66%) of the objects, resulting in a Seyfert-type change for ∼38% of the objects, likely driven by variable accretion and/or obscuration. The broad Hβ line virtually disappears in 3/102 (∼3%) extreme cases. We discuss potential causes for these changing look active galactic nuclei. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case basis or in larger samples focusing on quasars at higher redshifts, our study provides statistical information on the frequency of Hβ line variability in a sample of low-redshift Seyfert galaxies.

  16. A LINK BETWEEN X-RAY EMISSION LINES AND RADIO JETS IN 4U 1630-47?

    SciTech Connect

    Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Broderick, Jess W.; Lee, Julia C.; Ponti, Gabriele; Tzioumis, Anastasios K.; Edwards, Philip G.

    2014-03-20

    Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. Here we present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find no evidence for any relativistic X-ray emission lines. Indeed, despite ∼5 × brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ≳ 20 × weaker than the line observed by Díaz Trigo et al. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby interstellar medium, in which case the X-ray emission lines might be unrelated to the radio emission.

  17. A Link between X-Ray Emission Lines and Radio Jets in 4U 1630-47?

    NASA Astrophysics Data System (ADS)

    Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Lee, Julia C.; Ponti, Gabriele; Tzioumis, Anastasios K.; Edwards, Philip G.; Broderick, Jess W.

    2014-03-01

    Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. Here we present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find no evidence for any relativistic X-ray emission lines. Indeed, despite ~5 × brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is >~ 20 × weaker than the line observed by Díaz Trigo et al. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby interstellar medium, in which case the X-ray emission lines might be unrelated to the radio emission.

  18. Asymmetric 511 keV Positron Annihilation Line Emission from the Inner Galactic Disk

    NASA Technical Reports Server (NTRS)

    Skinner, Gerry; Weidenspointner, Georg; Jean, Pierre; Knodlseder, Jurgen; Ballmoos, Perer von; Bignami, Giovanni; Diehl, Roland; Strong, Andrew; Cordier, Bertrand; Schanne, Stephane; Winkler, Christoph

    2008-01-01

    A recently reported asymmetry in the 511 keV gamma-ray line emission from the inner galactic disk is unexpected and mimics an equally unexpected one in the distribution of LMXBs seen at hard X-ray energies. A possible conclusion is that LMXBs are an important source of the positrons whose annihilation gives rise to the line. We will discuss these results, their statistical significance and that of any link between the two. The implication of any association between LMXBs and positrons for the strong annihilation radiation from the galactic bulge will be reviewed.

  19. Observation of narrow isotopic optical magnetic resonances in individual emission spectral lines of neon

    SciTech Connect

    Saprykin, E G; Sorokin, V A; Shalagin, A M

    2015-07-31

    Narrow resonances are observed in the course of recording the individual emission lines of the glow discharge in the mixture of isotopes {sup 20}Ne and {sup 22}Ne, depending on the strength of the longitudinal magnetic field. The position of resonances in the magnetic scale corresponds to the compensation of the isotopic shift for certain spectral lines due to the Zeeman effect. It is found that the contrast of the resonances is higher for the transitions between the highly excited energy levels, and the resonances themselves are formed in the zone of longitudinal spatial nonuniformity of the magnetic field. (laser applications and other topics in quantum electronics)

  20. Ti-44 Gamma-Ray Emission Lines from SN1987A Reveal an Asymmetric Explosion

    NASA Technical Reports Server (NTRS)

    Boggs, S. E.; Harrison, F. A.; Miyasaka, H.; Grefenstette, B. W.; Zoglauer, A.; Fryer, C. L.; Reynolds, S. P.; Alexander, D. M.; An, H.; Barret, D.; hide

    2015-01-01

    In core-collapse supernovae, titanium-44 (Ti-44) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As such, it provides a direct probe of the supernova engine. Observations of supernova 1987A (SN1987A) have resolved the 67.87- and 78.32-kilo-electron volt emission lines from decay of Ti-44 produced in the supernova explosion. These lines are narrow and redshifted with a Doppler velocity of 700 kilometers per second, direct evidence of large-scale asymmetry in the explosion.

  1. Chromospheric Line Emission Analysis of the July 16, 2004 Sun Quake

    NASA Astrophysics Data System (ADS)

    Beşliu-Ionescu, Diana; Donea, Alina; Cally, Paul; Lindsey, Charles

    2007-09-01

    Observations in chromospheric lines and the visible continuum together with photospheric helioseismic measurements make possible to image a 3-dimensional profile of a sun quake in a flaring region. Chromospheric line observations show us the part of the solar atmosphere where high-energy electrons are thought to cause thick target heating that then could also cause intense white-light emission and could drive seismic waves into the active region subphotosphere, we present here the preliminary results of the sun quake of July 16, 2004.

  2. Ti-44 Gamma-Ray Emission Lines from SN1987A Reveal an Asymmetric Explosion

    NASA Technical Reports Server (NTRS)

    Boggs, S. E.; Harrison, F. A.; Miyasaka, H.; Grefenstette, B. W.; Zoglauer, A.; Fryer, C. L.; Reynolds, S. P.; Alexander, D. M.; An, H.; Barret, D.; Christensen, F. E.; Craig, W. W.; Forster, K.; Giommi, P.; Hailey, C. J.; Hornstrup, A.; Kitaguchi, T.; Koglin, J. E.; Madsen, K. K.; Zhang, W. W.

    2015-01-01

    In core-collapse supernovae, titanium-44 (Ti-44) is produced in the innermost ejecta, in the layer of material directly on top of the newly formed compact object. As such, it provides a direct probe of the supernova engine. Observations of supernova 1987A (SN1987A) have resolved the 67.87- and 78.32-kilo-electron volt emission lines from decay of Ti-44 produced in the supernova explosion. These lines are narrow and redshifted with a Doppler velocity of 700 kilometers per second, direct evidence of large-scale asymmetry in the explosion.

  3. Emission-line diagnostics for the existence of thermal accretion disks in active galactic nuclei

    NASA Technical Reports Server (NTRS)

    Krolik, J. H.

    1988-01-01

    The use of the relative strengths of optical and UV emission lines to infer information about the EUV continuum shape is demonstrated. The FeII/H-beta line ratio is strongly dependent on spectral shape, making it a good indicator of the UV spectrum. It is shown how the gravitational influence of a massive black hole may be seen in the nature of gas streaming motions and the orbits of gas clouds in the region where the black hole potential is comparable to the stellar galactic potential.

  4. Asymmetric 511 keV Positron Annihilation Line Emission from the Inner Galactic Disk

    NASA Technical Reports Server (NTRS)

    Skinner, Gerry; Weidenspointner, Georg; Jean, Pierre; Knodlseder, Jurgen; Ballmoos, Perer von; Bignami, Giovanni; Diehl, Roland; Strong, Andrew; Cordier, Bertrand; Schanne, Stephane; hide

    2008-01-01

    A recently reported asymmetry in the 511 keV gamma-ray line emission from the inner galactic disk is unexpected and mimics an equally unexpected one in the distribution of LMXBs seen at hard X-ray energies. A possible conclusion is that LMXBs are an important source of the positrons whose annihilation gives rise to the line. We will discuss these results, their statistical significance and that of any link between the two. The implication of any association between LMXBs and positrons for the strong annihilation radiation from the galactic bulge will be reviewed.

  5. Metal emissions from brake linings and tires: case studies of Stockholm, Sweden 1995/1998 and 2005.

    PubMed

    Hjortenkrans, David S T; Bergbäck, Bo G; Häggerud, Agneta V

    2007-08-01

    Road traffic has been highlighted as a major source of metal emissions in urban areas. Brake linings and tires are known emission sources of particulate matter to air; the aim of the current study was to follow the development of metal emissions from these sources over the period 1995/ 1998-2005, and to compare the emitted metal quantities to other metal emission sources. Stockholm, Sweden was chosen as a study site. The calculations were based on material metal concentrations, traffic volume, particle emission factors, and vehicle sales figures. The results for metal emissions from brake linings/tire tread rubber in 2005 were as follows: Cd 0.061/0.47 kg/year, Cu 3800/5.3 kg/year, Pb 35/3.7 kg/year, Sb 710/0.54 kg/year, and Zn 1000/4200 kg/ year. The calculated Cu and Zn emissions from brake linings were unchanged in 2005 compared to 1998, indicating that brake linings still remain one of the main emission sources for these metals. Further, brake linings are a source of antimony. In contrast, Pb and Cd emissions have decreased to one tenth compared to 1998. The results also showed that tires still are one of the main sources of Zn and Cd emissions in the city.

  6. Interplanetary particle observations associated with solar flare gamma-ray line emission

    NASA Technical Reports Server (NTRS)

    Von Rosenvinge, T. T.; Ramaty, R.; Reames, D. V.

    1981-01-01

    Observations of particle emissions during three solar flares which were observed to emit 2.22 MeV gamma rays as recorded by the Solar Maximum Mission are discussed. The 2.22 MeV line is produced by neutron capture by hydrogen, and additional attention is given to a 4.4 MeV emission line of June 7, 1980, with estimates made of the particle density 1 AU from the sun assuming a good magnetic connection between the earth and the sun. The measurements were made from the ISEE-3 and HELIOS-1 spacecraft. The connectedness of the earth and the sun in a magnetic field leads to conclusions that few particles actually escaped into interplanetary space.

  7. Spectroscopy of emission-line nebulae in powerful radio galaxies - Interpretation

    NASA Astrophysics Data System (ADS)

    Baum, S. A.; Heckman, T. M.; van Breugel, W.

    1992-04-01

    Long-slit optical spectra of the emission-line nebulae associated with 21 low-redshift (less than 0.2) radio galaxies are analyzed. Nebulae are classified kinematically into three types: rotators, calm nonrotators, and violent nonrotators; these types are characterized. It is proposed that the rotators have dynamically young disks of gas recently acquired by the radio galaxy in an interaction or merger with a gas-rich galaxy. This is consistent with the data on the morphologies, colors, and stellar dynamics of radio galaxies with strong emission lines. It is inferred from the association of the large-scale gas kinematics with the radio and optical properties of an active galaxy that the angular momentum of the gas which fuels the AGN may be an important parameter in the determinant of how activity is manifest in an AGN.

  8. The early-type strong emission-line supergiants of the Magellanic Clouds - A spectroscopic zoology

    NASA Technical Reports Server (NTRS)

    Shore, S. N.; Sanduleak, N.

    1984-01-01

    The results of a spectroscopic survey of 21 early-type extreme emission line supergiants of the Large and Small Magellanic Clouds using IUE and optical spectra are presented. The combined observations are discussed and the literature on each star in the sample is summarized. The classification procedures and the methods by which effective temperatures, bolometric magnitudes, and reddenings were assigned are discussed. The derived reddening values are given along with some results concerning anomalous reddening among the sample stars. The derived mass, luminosity, and radius for each star are presented, and the ultraviolet emission lines are described. Mass-loss rates are derived and discussed, and the implications of these observations for the evolution of the most massive stars in the Local Group are addressed.

  9. Spectroscopic studies of four planetary nebulae with emission-line nuclei

    NASA Astrophysics Data System (ADS)

    Burlak, M. A.; Kniazev, A. Yu.

    2013-10-01

    Spectroscopic observations of four planetary nebulae (PNe) with emission-line central stars of different spectral types are presented: Cn 1-5, Pe 1-1, NGC 5873, and M1-19. The interstellar extinction, physical conditions ( n e , T e ), and abundances of several elements (He, N, O, Ne, S, Ar, Cl) have been determined for all nebulae. The nebula Cn 1-5 with fairly high abundances of helium and nitrogen is shown to belong to type I PNe. Possible variability of the intensities of low-excitation emission lines in NGC 5873 has been found; it can be related to variations of the stellar wind from the central star. The measured α-element abundance ratios (S/O, Ne/O, Ar/O, Cl/O) are in good agreement with those typical of HII regions.

  10. Ten deep blue to cyan emission lines from an intracavity frequency converted Raman laser

    NASA Astrophysics Data System (ADS)

    Geskus, Dimitri; Jakutis-Neto, Jonas; Pask, Helen M.; Wetter, Niklaus U.

    2015-02-01

    Here we report on the generation of ten deep blue to cyan laser emission lines using an intracavity frequency converted Raman laser. The fundamental laser field of the intracavity Raman laser is based on the 3 level transition of a Nd:YLF laser crystal, providing a short wavelength at 903 or 908 nm. When combined with generation of a Stokes shifted field via intracavity stimulated Raman scattering (SRS) by a KGW Raman crystal, enables generation of laser emission in the deep blue to cyan wavelength regime via additional nonlinear frequency conversion. Output at several blue-green wavelengths was achieved, with quasi continuous wave (qcw) output powers of up to 1W. A detailed study of the spectral behavior of the underlying Raman laser processes revealed strong spectral broadening of the fundamental laser line at 908 nm to a width of up to 4 nm. The effect of the spectral broadening on the overall laser efficiency is analyzed.

  11. Photometric redshifts and clustering of emission line galaxies selected jointly by DES and eBOSS

    DOE PAGES

    Jouvel, S.; Delubac, T.; Comparat, J.; ...

    2017-03-24

    We present the results of the first test plates of the extended Baryon Oscillation Spectroscopic Survey. This paper focuses on the emission line galaxies (ELG) population targetted from the Dark Energy Survey (DES) photometry. We analyse the success rate, efficiency, redshift distribution, and clustering properties of the targets. From the 9000 spectroscopic redshifts targetted, 4600 have been selected from the DES photometry. The total success rate for redshifts between 0.6 and 1.2 is 71\\% and 68\\% respectively for a bright and faint, on average more distant, samples including redshifts measured from a single strong emission line. We find a meanmore » redshift of 0.8 and 0.87, with 15 and 13\\% of unknown redshifts respectively for the bright and faint samples. In the redshift range 0.6« less

  12. The Emission-line Spectra of Major Mergers: Evidence for Shocked Outflows

    NASA Astrophysics Data System (ADS)

    Soto, Kurt T.; Martin, C. L.; Prescott, M. K. M.; Armus, L.

    2012-09-01

    Using a spectral decomposition technique, we investigate the physical origin of the high-velocity emission-line gas in a sample of 39 gas-rich, ultraluminous infrared galaxy mergers. Regions with shock-like excitation were identified in two kinematically distinct regimes, characterized by broad (σ > 150 km s-1) and narrow linewidths (σ <= 150 km s-1). Here, we investigate the physical origin of the broad emission, which we show is predominantly excited by shocks with velocities of 200-300 km s-1. Considering the large amount of extinction in these galaxies, the blueshift of the broad emission suggests an origin on the near side of the galaxy and therefore an interpretation as a galactic outflow. The large spatial extent of the broad, shocked emission component is generally inconsistent with an origin in the narrow-line region of an active galactic nucleus. The kinetic energy in the mass loss as well as the luminosity of the emission lines is consistent with the fraction of the supernova energy attributed to these mechanisms by shocked stellar winds. Since some shocks can be recognized in moderately high resolution, integrated spectra of nearby ultraluminous starbursts, the spectral fitting technique introduced in Soto & Martin may therefore be used to improve the accuracy of the physical properties measured for high-redshift galaxies from their (observed frame) infrared spectra. The data presented herein were 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 the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  13. Performance of a Line Loss Correction Method for Gas Turbine Emission Measurements

    NASA Astrophysics Data System (ADS)

    Hagen, D. E.; Whitefield, P. D.; Lobo, P.

    2015-12-01

    International concern for the environmental impact of jet engine exhaust emissions in the atmosphere has led to increased attention on gas turbine engine emission testing. The Society of Automotive Engineers Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter from aircraft engines, and is developing an Aerospace Recommended Practice (ARP) for methodology and system specification. The Missouri University of Science and Technology (MST) Center for Excellence for Aerospace Particulate Emissions Reduction Research has led numerous jet engine exhaust sampling campaigns to characterize emissions at different locations in the expanding exhaust plume. Particle loss, due to various mechanisms, occurs in the sampling train that transports the exhaust sample from the engine exit plane to the measurement instruments. To account for the losses, both the size dependent penetration functions and the size distribution of the emitted particles need to be known. However in the proposed ARP, particle number and mass are measured, but size is not. Here we present a methodology to generate number and mass correction factors for line loss, without using direct size measurement. A lognormal size distribution is used to represent the exhaust aerosol at the engine exit plane and is defined by the measured number and mass at the downstream end of the sample train. The performance of this line loss correction is compared to corrections based on direct size measurements using data taken by MST during numerous engine test campaigns. The experimental uncertainty in these correction factors is estimated. Average differences between the line loss correction method and size based corrections are found to be on the order of 10% for number and 2.5% for mass.

  14. Ongoing Search for Metal Line Emission in Intermediate and High Velocity Clouds with WHAM

    NASA Astrophysics Data System (ADS)

    Barger, K. A.; Haffner, L. M.; Madsen, G. J.; Hill, A. S.; Wakker, B. P.

    2010-01-01

    We present new observations of the ionized gas in Complexes A, K, and L obtained with the Wisconsin H-Alpha Mapper (WHAM). To date, there have been only a limited number of studies of the ionized components of intermediate and high velocity clouds. Investigating their emission provides a rare probe of the physical conditions of the clouds and the halo they are embedded within. These types of measurements will help guide discussion of the origin and evolution of these neutral halo structures. Here we follow up on the H-alpha maps we have presented elsewhere with deeper observations in H-alpha, [S II], [N II], and [O I]. Distance constraints from absorption studies place this gas in the mid to lower Galactic halo. Complex A has been constrained to a distance of 8-10 kpc (Wakker et al. 2008); Complex K has an upper limit of 6.8 kpc; and Complex L at a distance of 8-15 kpc (Wakker 2000). Some halo gas structures have clear metal line emission (e.g., Smith Cloud; Hill et al. 2009 and this meeting); however, the lack of [S II] emission toward Complex C combined with absorption-line observations demonstrates that it has very low metallically (Wakker, et al. 1999). Such discoveries reveal ongoing gas replenishment of the evolving Milky Way. Here, we find a similar lack of emission toward the high-velocity Complex A. In particular, the cores of its cloud components designated III and IV show no evidence for metal line emission in our new observations, which places new constraints on the metallically of this complex. These observations were taken with WHAM at Kitt Peak, and we thank the excellent, decade-long support from its staff. WHAM operations are supported through NSF award AST-0607512.

  15. First detection of extragalactic 13CO(6-5) line emission

    NASA Astrophysics Data System (ADS)

    Stacey, G. J.; Hailey-Dunsheath, S.; Nikola, T.; Oberst, T. E.; Parshley, S. C.; Bradford, C. M.

    We report the first detection of a mid-J isotopic CO line from an external galaxy. We detected the 13CO (6-5) line from the starburst nucleus of NGC 253. The line is suprisingly bright with an integrated intensity 7% of the 12CO (6-5) line, indicating optical depth in the 12CO line. Our LVG modeling shows that a single warm (T ~ 120 K), dense (n ~ 104 cm-3) component emits most of the 12CO and 13CO line emission from J = 2-1 through J = 7-6. The CO(1-0) line comes from an additional lower excitation envelope. About 60% of the total molecular gas mass within 70 pc of the nucleus is in the warm, dense component. We show that stellar far-UV photons or X-ray photons from a nuclear source are unlikely to be the primary sources of the gas heating. The most likely sources of heat are cosmic rays from the nuclear starburst or microturbulence within molecular clouds.

  16. 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.

  17. Ionisation Chambers and Secondary Emission Monitors at the PROSCAN Beam Lines

    NASA Astrophysics Data System (ADS)

    Dölling, Rudolf

    2006-11-01

    PROSCAN, the dedicated new medical facility at PSI using proton beams for the treatment of deep seated tumours and eye melanoma, is now in the commissioning phase. Air filled ionisation chambers in several configurations are used as current monitors, profile monitors, halo, position and loss monitors at the PROSCAN beam lines. Similar monitors based on secondary emission are used for profile and current measurements in the regime where saturation deteriorates the accuracy of the ionisation chambers.

  18. 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

  19. A joint program with Japanese investigators to map carbon 2 line emission from the galaxy

    NASA Technical Reports Server (NTRS)

    Low, Frank J.; Nishimura, Tetsuo

    1993-01-01

    A large portion of the inner galactic plane has been mapped in the far-infrared (C II) line using a balloon-borne survey instrument. Complete coverage is reported from 25 degrees north to 80 degrees south of the galactic center and extending a few degrees on each side of the plane. Effective resolution is 14.1 acrmin (FWHM) and contour levels begin at 2 E -5 ergs/(s x sq. cm x ster). When compared with 100 micron dust emission observed by IRAS the (C II) appears well correlated with the dust emission except for a 10 degree region centered on the galactic center where emission from the gas is much weaker than that from the dust.

  20. SERTS-95 Measurements of Wavelength Shifts in Coronal Emission Lines Across a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Brosius, Jeffery W.; Thomas, Roger; Davila, Joseph

    1999-01-01

    We used slit spectra from the 1995 flight of Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS-95) to measure wavelength shifts of coronal emission lines in the core of NOAA active region 7870 relative to its immediate surroundings (its "edge"). This method circumvents the unavailability of reliable laboratory rest wavelengths for the observed lines by using wavelengths from the edge spectrum as references. We derived the, SERTS-95 wavelength calibration from measurements of a post-flight laboratory spectrum containing 28 He II and Ne II EUV standard wavelengths known to high accuracy. Wavelength measurements for lines of He I, Ne III, and additional lines of Ne II in the laboratory calibration spectrum provide more accurate values than were previously available, enabling these lines also to serve as future calibration standards. Six solar lines were chosen for this study, namely, He II at 303.78 A, Fe XII at 193.51 A, Fe XIII at 202.05 A, Fe XIV at 211.33 A, Fe XV at 284.15 A, and Fe XVI at 335.41 A. Because these lines are free from known blends in the SERTS-95 spectra and are either intrinsically strong or near the SERTS-95 peak sensitivity, they are our most reliable lines for measuring relative wavelength shifts in the spatially resolved active region core spectra. The iron ions are the hottest ions ever used for this type of analysis. All six lines reveal statistically significant spatial variations in their measured relative wavelength shifts in the active region core, including mixtures of blueshifts and redshifts (each with maximum values corresponding to relative Doppler velocities approximately 15 km/s), indicating a dynamic, turbulent corona. For each of these lines we calculated weighted-average relative Doppler velocities from the wavelength shifts in the spatially resolved core spectra by weighting the shifts in the individual spatial pixels with their respective measurement uncertainties.

  1. [Study on the quality of spectral line of laser microprobe emission spectral analysis].

    PubMed

    Guo, Qing-lin; Zhang, Qiu-lin; Liang, Bao-lai; Wei, Yan-hong; Huai, Su-fang

    2003-02-01

    In this paper, the quality improvement of Laser Microprobe Emission Spectral Analysis (LMESA) lines in argon atmosphere at reduced pressure was experimentally investigated. The experimental setup consists of a YGJ-II laser micro-spectral analyzer and a photo-electro detection system. The temporal behavior and the intensity distribution of Cu I 324.7 nm and Cu I 327.4 nm lines of the copper alloy standard samples were studied. The results show that LMESA spectrum strongly depends on the environment gas, its pressure and the auxiliary excitation parameters. When the diameter at the end of graphite auxiliary electrodes is 1.5 mm, the distance between the electrodes is 4 mm, the center of the electrodes is 3 mm above the sample surface, the voltage of the auxiliary excitation is 1,300 V and the argon pressure is 33.2 Kpa, the emission time of Cu I 324.7 nm and Cu I 327.4 nm is about 500 microseconds longer than that in the air. The emission intensity of Cu I 324.7 nm and Cu I 327.4 nm is about 4 times higher than that in the air at the same pressure and is about 2 times higher than that in the air at normal pressure. The full width at half maximum of the spectral lines is obviously narrowed.

  2. Hard X-ray emission and {sup 44}Ti line features of the Tycho supernova remnant

    SciTech Connect

    Wang, Wei; Li, Zhuo E-mail: zhuo.li@pku.edu.cn

    2014-07-10

    A deep hard X-ray survey of the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) satellite has detected for the first time non-thermal emission up to 90 keV in the Tycho supernova (SN) remnant. Its 3-100 keV spectrum is fitted with a thermal bremsstrahlung of kT ∼ 0.81 ± 0.45 keV plus a power-law model of Γ ∼ 3.01 ± 0.16. Based on diffusive shock acceleration theory, this non-thermal emission, together with radio measurements, implies that the Tycho remnant may not accelerate protons up to >PeV but to hundreds TeV. Only heavier nuclei may be accelerated to the cosmic ray spectral 'knee'. In addition, using INTEGRAL, we search for soft gamma-ray lines at 67.9 and 78.4 keV that come from the decay of radioactive {sup 44}Ti in the Tycho remnant. A bump feature in the 60-90 keV energy band, potentially associated with the {sup 44}Ti line emission, is found with a marginal significance level of ∼2.6σ. The corresponding 3σ upper limit on the {sup 44}Ti line flux amounts to 1.5 × 10{sup –5} photon cm{sup –2} s{sup –1}. Implications on the progenitor of the Tycho SN, considered to be a Type Ia SN prototype, are discussed.

  3. Photometry of the 4686 A emission line of gamma(2) Velorum from the South Pole

    NASA Technical Reports Server (NTRS)

    Taylor, Maryjane

    1990-01-01

    An automated optical telescope located at the Amundsen-Scott South Pole station on Antarctica, has been used to obtain more than 78 h of photometry of the He II emission line (4686 A) of the spectroscopic binary gamma(2) Velorum. These data were obtained on seven different days during the 1987 austral winter; the longest continuous run spans 19 h. Two independent period search techniques have been used to search for periodic behavior in the strength of the He II emission line of this Wolf-Rayet star. They are: (1) power spectrum analysis and (2) a first-order sine function fit to the data using least squares. Various multiplicities of a period on the order of 1.3 h with amplitudes of a few percent are found in most of these data. According to recent theoretical models of Wolf-Rayet stars, fluctuations in the He II emission line may indicate vibrational instability in gamma(2) Vel. These pulsations may, in turn, give rise to shocks which propagate outward and which may provide the necessary conditions for periodic changes in the state of a given region of the atmosphere to occur.

  4. Predicted emission lines from giant HII regions ionized by aging star clusters.

    NASA Astrophysics Data System (ADS)

    Garcia-Vargas, M. L.; Bressan, A.; Diaz, A. I.

    1995-07-01

    We have computed theoretical models of the emission line spectra of giant extragalactic HII regions (GEHR) in which a single star cluster is assumed to be responsible for the ionization. Ionizing clusters, of different masses and metallicities, were constructed assuming that they formed in a single burst and with a Salpeter Initial Mass Function. Their evolution was then followed in detail up to an age of 5.4Myr after which they lack the high energy photons needed to keep the regions ionized. The integrated spectral energy distribution of every cluster has been computed for a set of discrete ages representative of relevant phases of their evolution and have been processed by the photoionization code CLOUDY, in order to obtain the corresponding emission line spectra of the ionized gas at optical and infrared wavelengths. A wide range of initial compositions, spanning from about 1/20 (Z=0.001) to 2.5 solar (Z=0.05), and total masses, between about 1-6x10^4^Msun_ has been considered. Gas and stars are assumed to have the same metallicity and this has been taken into account both in the stellar evolution and atmosphere models and in the nebular gas producing a consistent set of models. In this paper we present the synthetic emission line spectra of the ionized regions which are discussed in detail in Garcia-Vargas et al. (1995).

  5. Photometry of the 4686 A emission line of gamma(2) Velorum from the South Pole

    SciTech Connect

    Taylor, M. Florida Univ., Gainesville )

    1990-10-01

    An automated optical telescope located at the Amundsen-Scott South Pole station on Antarctica, has been used to obtain more than 78 h of photometry of the He II emission line (4686 A) of the spectroscopic binary gamma(2) Velorum. These data were obtained on seven different days during the 1987 austral winter; the longest continuous run spans 19 h. Two independent period search techniques have been used to search for periodic behavior in the strength of the He II emission line of this Wolf-Rayet star. They are: (1) power spectrum analysis and (2) a first-order sine function fit to the data using least squares. Various multiplicities of a period on the order of 1.3 h with amplitudes of a few percent are found in most of these data. According to recent theoretical models of Wolf-Rayet stars, fluctuations in the He II emission line may indicate vibrational instability in gamma(2) Vel. These pulsations may, in turn, give rise to shocks which propagate outward and which may provide the necessary conditions for periodic changes in the state of a given region of the atmosphere to occur. 15 refs.

  6. EXTREME EMISSION-LINE GALAXIES IN CANDELS: BROADBAND-SELECTED, STARBURSTING DWARF GALAXIES AT z > 1

    SciTech Connect

    Van der Wel, A.; Rix, H.-W.; Jahnke, K.; Straughn, A. N.; Finkelstein, S. L.; Salmon, B. W.; Koekemoer, A. M.; Ferguson, H. C.; Weiner, B. J.; Wuyts, S.; Bell, E. F.; Faber, S. M.; Trump, J. R.; Koo, D. C.; Hathi, N. P.; Dunlop, J. S.; Newman, J. A.; Dickinson, M.; De Mello, D. F.; and others

    2011-12-01

    We identify an abundant population of extreme emission-line galaxies (EELGs) at redshift z {approx} 1.7 in the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey imaging from Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3). Sixty-nine EELG candidates are selected by the large contribution of exceptionally bright emission lines to their near-infrared broadband magnitudes. Supported by spectroscopic confirmation of strong [O III] emission lines-with rest-frame equivalent widths {approx}1000 A-in the four candidates that have HST/WFC3 grism observations, we conclude that these objects are galaxies with {approx}10{sup 8} M{sub Sun} in stellar mass, undergoing an enormous starburst phase with M{sub *}/ M-dot{sub *} of only {approx}15 Myr. These bursts may cause outflows that are strong enough to produce cored dark matter profiles in low-mass galaxies. The individual star formation rates and the comoving number density (3.7 Multiplication-Sign 10{sup -4} Mpc{sup -3}) can produce in {approx}4 Gyr much of the stellar mass density that is presently contained in 10{sup 8}-10{sup 9} M{sub Sun} dwarf galaxies. Therefore, our observations provide a strong indication that many or even most of the stars in present-day dwarf galaxies formed in strong, short-lived bursts, mostly at z > 1.

  7. Anatomy of the AGN in NGC 5548: the X-ray narrow emission lines

    NASA Astrophysics Data System (ADS)

    Whewell, M.; Branduardi-Raymont, G.; Kaastra, J.; Mehdipour, M.; Bianchi, S.; NGC 5548 Collaboration

    2014-07-01

    After a very successful multi-satellite campaign on Mrk 509 in 2009, we conducted a similar campaign on the AGN NGC 5548 in 2013. During the latter the source appeared unusually strongly absorbed in the soft X-rays, and signatures of strong outflows were also present in the UV. While a talk giving an overview of the campaign (PI: J. Kaastra) is also proposed at this conference, we will focus here on the data obtained from the XMM-RGS, resulting in a stacked spectrum of 660 ks. Narrow emission lines, including He-like triplets of Oxygen, Nitrogen and Neon, and radiative recombination (RRC) features dominate this spectrum due to the low soft X-ray continuum flux. All emission features are consistent with having constant flux over our campaign. The O VII triplet has been one focus of our analysis, especially due to unexpected differences of ˜300 km s^{-1} among the measured outflow velocities of its individual lines. The RRCs allow us to directly calculate a temperature of the emitting gas of a few eV (˜10^{4}K), favouring photoionised conditions. We have modelled the emission lines and features using the photoionisation code Cloudy, to attempt to construct a self-consistent picture of the physical environment of the AGN.

  8. Study on Emission Spectral Lines of Iron, Fe in Laser-Induced Breakdown Spectroscopy (LIBS) on Soil Samples

    NASA Astrophysics Data System (ADS)

    Idris, Nasrullah; Lahna, Kurnia; Fadhli; Ramli, Muliadi

    2017-05-01

    In this work, LIBS technique has been used for detection of heavy metal especially iron, Fe in soil sample. As there are a large number of emission spectral lines due to Fe and other constituents in soil, this study is intended to identify emission spectral lines of Fe and finally to find best fit emission spectral lines for carrying out a qualitative and quantitative analysis. LIBS apparatus used in this work consists of a laser system (Neodymium Yttrium Aluminum Garnet, Nd-YAG: Quanta Ray; LAB SERIES; 1,064 nm; 500 mJ; 8 ns) and an optical multichannel analyzer (OMA) system consisting of a spectrograph (McPherson model 2061; 1,000 mm focal length; f/8.6 Czerny- Turner) and an intensified charge coupled device (ICCD) 1024x256 pixels (Andor I*Star). The soil sample was collected from Banda Aceh city, Aceh, Indonesia. For spectral data acquisition, the soil sample has been prepared by a pressing machine in the form of pellet. The laser beam was focused using a high density lens (f=+150 mm) and irradiated on the surface of the pellet for generating luminous plasma under 1 atmosphere of air surrounding. The plasma emission was collected by an optical fiber and then sent to the optical multichannel analyzer (OMA) system for acquisition of the emission spectra. It was found that there are many Fe emission lines both atomic lines (Fe I) and ionic lines (Fe II) appeared in all detection windows in the wavelength regions, ranging from 200 nm to 1000 nm. The emission lines of Fe with strong intensities occurs together with emission lines due to other atoms such as Mg, Ca, and Si. Thus, the identification of emission lines from Fe is complicated by presence of many other lines due to other major and minor elements in soil. Considering the features of the detected emission lines, several emission spectral lines of Fe I (atomic emission line), especially Fe I 404.58 nm occurring at visible range are potential to be good candidate of analytical lines in relation to detection

  9. ALMA IMAGING OF THE CO (6-5) LINE EMISSION IN NGC 7130

    SciTech Connect

    Zhao, Yinghe; Lu, Nanyao; Xu, C. Kevin; Appleton, Philip; Murphy, Eric; Gao, Yu; Barcos-Munõz, Loreto; Díaz-Santos, Tanio; Charmandaris, Vassilis; Armus, Lee; Van der Werf, Paul; Evans, Aaron; Cao, Chen; Inami, Hanae

    2016-04-01

    In this paper, we report our high-resolution (0.″20 × 0.″14 or ∼70 × 49 pc) observations of the CO(6-5) line emission, which probes warm and dense molecular gas, and the 434 μm dust continuum in the nuclear region of NGC 7130, obtained with the Atacama Large Millimeter Array (ALMA). The CO line and dust continuum fluxes detected in our ALMA observations are 1230 ± 74 Jy km s{sup −1} and 814 ± 52 mJy, respectively, which account for 100% and 51% of their total fluxes. We find that the CO(6-5) and dust emissions are generally spatially correlated, but their brightest peaks show an offset of ∼70 pc, suggesting that the gas and dust emissions may start decoupling at this physical scale. The brightest peak of the CO(6-5) emission does not spatially correspond to the radio continuum peak, which is likely dominated by an active galactic nucleus (AGN). This, together with our additional quantitative analysis, suggests that the heating contribution of the AGN to the CO(6-5) emission in NGC 7130 is negligible. The CO(6-5) and the extinction-corrected Pa-α maps display striking differences, suggestive of either a breakdown of the correlation between warm dense gas and star formation at linear scales of <100 pc or a large uncertainty in our extinction correction to the observed Pa-α image. Over a larger scale of ∼2.1 kpc, the double-lobed structure found in the CO(6-5) emission agrees well with the dust lanes in the optical/near-infrared images.

  10. ALMA Imaging of the CO (6-5) Line Emission in NGC 7130*

    NASA Astrophysics Data System (ADS)

    Zhao, Yinghe; Lu, Nanyao; Xu, C. Kevin; Gao, Yu; Barcos-Munõz, Loreto; Díaz-Santos, Tanio; Appleton, Philip; Charmandaris, Vassilis; Armus, Lee; van der Werf, Paul; Evans, Aaron; Cao, Chen; Inami, Hanae; Murphy, Eric

    2016-04-01

    In this paper, we report our high-resolution (0.″20 × 0.″14 or ˜70 × 49 pc) observations of the CO(6-5) line emission, which probes warm and dense molecular gas, and the 434 μm dust continuum in the nuclear region of NGC 7130, obtained with the Atacama Large Millimeter Array (ALMA). The CO line and dust continuum fluxes detected in our ALMA observations are 1230 ± 74 Jy km s-1 and 814 ± 52 mJy, respectively, which account for 100% and 51% of their total fluxes. We find that the CO(6-5) and dust emissions are generally spatially correlated, but their brightest peaks show an offset of ˜70 pc, suggesting that the gas and dust emissions may start decoupling at this physical scale. The brightest peak of the CO(6-5) emission does not spatially correspond to the radio continuum peak, which is likely dominated by an active galactic nucleus (AGN). This, together with our additional quantitative analysis, suggests that the heating contribution of the AGN to the CO(6-5) emission in NGC 7130 is negligible. The CO(6-5) and the extinction-corrected Pa-α maps display striking differences, suggestive of either a breakdown of the correlation between warm dense gas and star formation at linear scales of <100 pc or a large uncertainty in our extinction correction to the observed Pa-α image. Over a larger scale of ˜2.1 kpc, the double-lobed structure found in the CO(6-5) emission agrees well with the dust lanes in the optical/near-infrared images. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  11. Properties of Solar Flare Plasmas Derived from Soft X-Ray Line Emission.

    NASA Astrophysics Data System (ADS)

    Bornmann, Patricia Lee

    A new observational property of soft X-ray line fluxes observed during the decay phase of solar flares is described and a new technique is presented for determining the plasma temperature and emission measure as functions of time based on this property. Results of this technique indicate the need for continuous heating or an intermediate energy storage mechanism during the flare. Fluid turbulence is examined as a possible intermediate energy storage mechanism. The soft X-ray line fluxes observed by SMM's FCS during the gradual phase of the 1980 November 5 flare did not decay at a constant rate. The line flux decay rate changed abruptly, with the line fluxes falling more rapidly later in the flare decay. These changes occurred at earlier times for lines formed at higher temperatures. This behavior is proposed to be due to the decreasing temperature of the flare plasma tracking the rise and subsequent fall of each line emissivity function. The proposed explanation for the rate changes was used to develop a technique for estimating the temperature and emission measure as a function of time during the gradual phase of solar flares. Eight flares were modeled with this technique and the model fits were repeated for each flare using five different sets of published line emissivity calculations. Estimates were made of various plasma parameters based on the model results during the decay of the 1980 November 5 flare. The mass was found to remain constant as the volume expanded, and the change in thermal energy was insufficient to account for the predicted total radiative losses, indicating the need for additional heating during the decay phase of this flare. Turbulence is proposed as a method for converting the energy observed as mass motions during the impulsive phase into thermal energy and the subsequent thermal radiation observed during the gradual phase of solar flares. The general properties of steady state, homogeneous fluid turbulence and of turbulent decay are

  12. Molecular line emission in HH54: a coherent view from near to far infrared

    NASA Astrophysics Data System (ADS)

    Giannini, T.; McCoey, C.; Nisini, B.; Cabrit, S.; Caratti o Garatti, A.; Calzoletti, L.; Flower, D. R.

    2006-12-01

    Aims.We present a detailed study of the infrared line emission (1-200 μm) in the Herbig-Haro object HH54. Our database comprises: high- (R ~ 9000) and low- (R ~ 600) resolution spectroscopic data in the near-infrared band (1-2.5 μm); mid-infrared spectrophotometric images (5-12 μm); and, far-IR (45-200 μm, R ~ 200) spectra acquired with the ISO satellite. As a result, we provide the detection of and the absolute fluxes for more than 60 molecular features (mainly from H2 in the near- and mid-infrared and from H2O, CO and OH in the far-infrared) and 23 ionic lines. Methods: .The H2 lines, coming from levels from v = 0 to v = 4 have been interpreted in the context of a state-of-the-art shock code, whose output parameters are adopted as input to a Large Velocity Gradient computation in order to interpret the FIR emission of CO, H2O and OH. Results: .The H2 emission can be interpreted as originating in either steady-state J-type shocks or in quasi-steady J-type shocks with magnetic precursor. However, our multi-species analysis shows that only a model of a J-type shock with magnetic precursor (vshock = 18 km s-1, nH = 104 cm-3, B = 100 μG, age = 400 yr) can account for both the observed H2 emission and the CO and H2O lines. Such a model predicts a H2O abundance of ~7 × 10-5, in agreement with estimations from other shock models of outflows associated with low mass protostars. We can exclude the possibility that the observed atomic lines arise in the same shock as the molecular lines, and give arguments in favour of the presence of a further high-velocity, fully dissociative shock component in the region. Finally, in view of the forthcoming spectroscopic facilities on board of the Herschel satellite, we provide predictions for H2O lines considered to be the most suitable for diagnostic purposes.

  13. Relation between the Variations in the Mg ii λ2798 Emission Line and 3000 Å Continuum

    NASA Astrophysics Data System (ADS)

    Zhu, Dongchun; Sun, Mouyuan; Wang, Tinggui

    2017-07-01

    We investigate the relationship between the {Mg} {{II}} λ 2798 emission line and the 3000 Å continuum variations using a sample of 68 intermediate-redshift (z˜ 0.65{--}1.50) broad-line quasars spanning a bolometric luminosity range of 44.49 erg {{{s}}}-1≤slant {log}{L}{bol}≤slant 46.31 erg s-1 (Eddington ratio from ˜0.026 to 0.862). This sample is constructed from SDSS-DR7Q and BOSS-DR12Q, each with at least two spectroscopic epochs in SDSS-I/II/III surveys. In addition, we adopt the following signal-to-noise ratio (S/N) selection criteria: (a) for {Mg} {{II}} and the 3000 Å continuum, S/N ≥slant 10; and (b) for narrow lines, S/N ≥slant 5. All our quasar spectra are recalibrated based on the assumption of constant narrow emission-line fluxes. In an analysis of spectrum-to-spectrum variations, we find a fairly close correlation (Spearman ρ =0.593) between the variations in broad {Mg} {{II}} and in the continuum. This is consistent with the idea that {Mg} {{II}} is varying in response to the continuum emission variations. Adopting the modified weighted least squares regression method, we statistically constrain the slopes (i.e., the responsivity α of the broad {Mg} {{II}}) between the variations in both components for the sources in different luminosity bins after eliminating intrinsic biases introduced by the rescaling process itself. It is shown that the responsivity is quite small (average \\bar{α }≈ 0.464) and anti-correlates with the quasar luminosity. Our results indicate that high signal-to-noise flux measurements are required to robustly detect the intrinsic variability and the time lag of the {Mg} {{II}} line.

  14. A First Comparison of Millimeter Continuum and Mg ii Ultraviolet Line Emission from the Solar Chromosphere

    NASA Astrophysics Data System (ADS)

    Bastian, T. S.; Chintzoglou, G.; De Pontieu, B.; Shimojo, M.; Schmit, D.; Leenaarts, J.; Loukitcheva, M.

    2017-08-01

    We present joint observations of the Sun by the Atacama Large Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging Spectrograph (IRIS). Both millimeter/submillimeter-λ continuum emission and ultraviolet (UV) line emission originate from the solar chromosphere and both have the potential to serve as powerful and complementary diagnostics of physical conditions in this enigmatic region of the solar atmosphere. The observations were made of a solar active region on 2015 December 18 as part of the ALMA science verification effort. A map of the Sun’s continuum emission was obtained by ALMA at a wavelength of 1.25 mm (239 GHz). A contemporaneous map was obtained by IRIS in the Mg ii h doublet line at 2803.5 Å. While a clear correlation between the 1.25 mm brightness temperature T B and the Mg ii h line radiation temperature T rad is observed, the slope is <1, perhaps as a result of the fact that these diagnostics are sensitive to different parts of the chromosphere and that the Mg ii h line source function includes a scattering component. There is a significant difference (35%) between the mean T B (1.25 mm) and mean T rad (Mg ii). Partitioning the maps into “sunspot,” “quiet areas,” and “plage regions” we find the relation between the IRIS Mg ii h line T rad and the ALMA T B region-dependent. We suggest this may be the result of regional dependences of the formation heights of the IRIS and ALMA diagnostics and/or the increased degree of coupling between the UV source function and the local gas temperature in the hotter, denser gas in plage regions.

  15. GRIS detection of Al-26 1809 keV line emission from the Galactic center region as a broad line

    NASA Technical Reports Server (NTRS)

    Naya, Juan E.; Barthelmy, Scott D.; Bartlett, Lyle M.; Gehrels, Neil; Leventhal, Marvin; Parsons, Ann; Teegarden, Bonnard J.; Tueller, Jack

    1997-01-01

    The gamma ray imaging spectrometer (GRIS) was used to observe the 1809 keV emission from the Galactic center region. The observed line is broader than the instrument resolution. The measured intrinsic width is 5.4 +/- 1.4 keV full width half medium, which is more than three times the maximum Doppler broadening expected due to Galactic rotation. The detection of such a wide feature, suggesting a high dispersion velocity has implications for the origin of Galactic Al-26. It suggests a supernova explosion origin or a Wolf-Rayet stellar wind origin of Al-26. The fact that the Al-26 has not come to rest after 10(exp 6) years presents a challenge to the current understanding of the Al-26 production and propagation in the Galaxy.

  16. 40 CFR 1048.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.320 What happens if one of my production-line engines fails to meet emission standards? If you have a production-line engine with final... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if one of my...

  17. 40 CFR 1054.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SPARK-IGNITION ENGINES AND EQUIPMENT Production-line Testing § 1054.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 34 2013-07-01 2013-07-01 false What happens if one of my...

  18. 40 CFR 1054.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SPARK-IGNITION ENGINES AND EQUIPMENT Production-line Testing § 1054.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What happens if one of my...

  19. 40 CFR 1045.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROPULSION MARINE ENGINES AND VESSELS Testing Production-line Engines § 1045.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What happens if one of my...

  20. 40 CFR 1054.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SPARK-IGNITION ENGINES AND EQUIPMENT Production-line Testing § 1054.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if one of my...

  1. 40 CFR 1048.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.320 What happens if one of my production-line engines fails to meet emission standards? If you have a production-line engine with final... 40 Protection of Environment 33 2014-07-01 2014-07-01 false What happens if one of my...

  2. 40 CFR 1048.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.320 What happens if one of my production-line engines fails to meet emission standards? If you have a production-line engine with final... 40 Protection of Environment 34 2013-07-01 2013-07-01 false What happens if one of my...

  3. 40 CFR 1045.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PROPULSION MARINE ENGINES AND VESSELS Testing Production-line Engines § 1045.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 32 2010-07-01 2010-07-01 false What happens if one of my...

  4. 40 CFR 1045.320 - What happens if one of my production-line engines fails to meet emission standards?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PROPULSION MARINE ENGINES AND VESSELS Testing Production-line Engines § 1045.320 What happens if one of my production-line engines fails to meet emission standards? (a) If you have a production-line engine with final... 40 Protection of Environment 34 2013-07-01 2013-07-01 false What happens if one of my...

  5. Inner Warm Disk of ESO Hα 279a Revealed by NA I and CO Overtone Emission Lines

    NASA Astrophysics Data System (ADS)

    Lyo, A.-Ran; Kim, Jongsoo; Lee, Jae-Joon; Kim, Kyoung-Hee; Kang, Jihyun; Byun, Do-Young; Mace, Gregory; Sokal, Kimberly R.; Park, Chan; Chun, Moo-Young; Oh, Heeyoung; Yu, Young Sam; Sok Oh, Jae; Jeong, Ueejeong; Kim, Hwihyun; Pak, Soojong; Hwang, Narae; Park, Byeong-Gon; Lee, Sungho; Kaplan, Kyle; Lee, Hye-In; Nguyen Le, Huynh Anh; Jaffe, Daniel; Friends of AASTeX Collaboration

    2017-07-01

    We present an analysis of near-infrared, high-resolution spectroscopy toward the flat-spectrum young stellar object (YSO) ESO Hα 279a (˜1.5M ⊙) in the Serpens star-forming region at a distance of 429 pc. Using the Immersion GRating INfrared Spectrometer (IGRINS; R ≈ 45,000), we detect emission lines originating from the accretion channel flow, jet, and inner disk. Specifically, we identify hydrogen Brackett series recombination, [Fe II], [Fe III], [Fe IV], Ca I, Na I, H2, H2O, and CO overtone emission lines. By modeling five bands of CO overtone emission lines and the symmetric double-peaked line profile for Na I emission lines, we find that ESO Hα 279a has an actively accreting Keplerian disk. From our Keplerian disk model, we find that Na I emission lines originate between 0.04 and 1.00 au, while the CO overtone emission lines are from the outer part of the disk, in the range between 0.22 and 3.00 au. The model reveals that the neutral atomic Na gas is a good tracer of the innermost region of the actively accreting disk. We derive a mass accretion rate of 2-10× 10-7 M ⊙ yr-1 from the measured Brγ emission luminosity of 1.78(±0.31) × 1031 erg s-1.

  6. EMISSION LINES FROM THE GAS DISK AROUND TW HYDRA AND THE ORIGIN OF THE INNER HOLE

    SciTech Connect

    Gorti, U.; Hollenbach, D.; Najita, J.; Pascucci, I.

    2011-07-10

    We compare line emission calculated from theoretical disk models with optical to submillimeter wavelength observational data of the gas disk surrounding TW Hya and infer the spatial distribution of mass in the gas disk. The model disk that best matches observations has a gas mass ranging from {approx}10{sup -4} to 10{sup -5} M{sub sun} for 0.06 AU < r < 3.5 AU and {approx}0.06 M{sub sun} for 3.5 AU < r < 200 AU. We find that the inner dust hole (r < 3.5 AU) in the disk must be depleted of gas by {approx}1-2 orders of magnitude compared with the extrapolated surface density distribution of the outer disk. Grain growth alone is therefore not a viable explanation for the dust hole. CO vibrational emission arises within r {approx} 0.5 AU from thermal excitation of gas. [O I] 6300 A and 5577 A forbidden lines and OH mid-infrared emission are mainly due to prompt emission following UV photodissociation of OH and water at r {approx}< 0.1 AU and at r {approx} 4 AU. [Ne II] emission is consistent with an origin in X-ray heated neutral gas at r {approx}< 10 AU, and may not require the presence of a significant extreme-ultraviolet (h{nu} > 13.6 eV) flux from TW Hya. H{sub 2} pure rotational line emission comes primarily from r {approx} 1 to 30 AU. [O I] 63 {mu}m, HCO{sup +}, and CO pure rotational lines all arise from the outer disk at r {approx} 30-120 AU. We discuss planet formation and photoevaporation as causes for the decrease in surface density of gas and dust inside 4 AU. If a planet is present, our results suggest a planet mass {approx}4-7 M{sub J} situated at {approx}3 AU. Using our photoevaporation models and the best surface density profile match to observations, we estimate a current photoevaporative mass loss rate of 4 x 10{sup -9} M{sub sun} yr{sup -1} and a remaining disk lifetime of {approx}5 million years.

  7. Gaia-ESO Survey: Gas dynamics in the Carina nebula through optical emission lines

    NASA Astrophysics Data System (ADS)

    Damiani, F.; Bonito, R.; Magrini, L.; Prisinzano, L.; Mapelli, M.; Micela, G.; Kalari, V.; Maíz Apellániz, J.; Gilmore, G.; Randich, S.; Alfaro, E.; Flaccomio, E.; Koposov, S.; Klutsch, A.; Lanzafame, A. C.; Pancino, E.; Sacco, G. G.; Bayo, A.; Carraro, G.; Casey, A. R.; Costado, M. T.; Franciosini, E.; Hourihane, A.; Lardo, C.; Lewis, J.; Monaco, L.; Morbidelli, L.; Worley, C.; Zaggia, S.; Zwitter, T.; Dorda, R.

    2016-06-01

    Aims: We present observations from the Gaia-ESO Survey in the lines of Hα, [N II], [S II], and He I of nebular emission in the central part of the Carina nebula. Methods: We investigate the properties of the two already known kinematic components (approaching and receding), which account for the bulk of emission. Moreover, we investigate the features of the much less known low-intensity high-velocity (absolute RV >50 km s-1) gas emission. Results: We show that gas giving rise to Hα and He I emission is dynamically well correlated with but not identical to gas seen through forbidden-line emission. Gas temperatures are derived from line-width ratios, and densities from [S II] doublet ratios. The spatial variation of N ionization is also studied, and found to differ between the approaching and receding components. The main result is that the bulk of the emission lines in the central part of Carina arise from several distinct shell-like expanding regions, the most evident found around η Car, the Trumpler 14 core, and the star WR25. These "shells" are non-spherical and show distortions probably caused by collisions with other shells or colder, higher-density gas. Some of them are also partially obscured by foreground dust lanes, while very little dust is found in their interior. Preferential directions, parallel to the dark dust lanes, are found in the shell geometries and physical properties, probably related to strong density gradients in the studied region. We also find evidence that the ionizing flux emerging from η Car and the surrounding Homunculus nebula varies with polar angle. The high-velocity components in the wings of Hα are found to arise from expanding dust reflecting the η Car spectrum. Based on observations collected with the FLAMES spectrograph at VLT/UT2 telescope (Paranal Observatory, ESO, Chile), for the Gaia-ESO Large Public Survey (program 188.B-3002).Full Tables 1-3 are only available at the CDS via anonymous ftp to http

  8. Emission Lines from the Gas Disk Around TW Hydra and the Origin of the Inner Hole

    NASA Technical Reports Server (NTRS)

    Gorti, U.; Hollenbach, D.; Najita, J.; Pascucci, I.

    2011-01-01

    We compare line emission calculated from theoretical disk models with optical to submillimeter wavelength observational data of the gas disk surrounding TW Hya and infer the spatial distribution of mass in the gas disk. The model disk that best matches observations has a gas mass ranging from approx.10(exp -4) to 10(exp -5) M for 0.06AU < r < 3.5 AU and approx. 0.06M for 3.5AU < r < 200 AU. We find that the inner dust hole (r < 3.5 AU) in the disk must be depleted of gas by approx. 1-2 orders of magnitude compared with the extrapolated surface density distribution of the outer disk. Grain growth alone is therefore not a viable explanation for the dust hole. CO vibrational emission arises within r approx. 0.5 AU from thermal excitation of gas. [O i] 6300Å and 5577Å forbidden lines and OH mid-infrared emission are mainly due to prompt emission following UV photodissociation of OH and water at r < or approx. 0.1 AU and at r approx. 4 AU. [Ne ii] emission is consistent with an origin in X-ray heated neutral gas at r < or approx. 10 AU, and may not require the presence of a significant extreme-ultraviolet (h? > 13.6 eV) flux from TW Hya. H2 pure rotational line emission comes primarily from r approx. 1 to 30 AU. [Oi] 63microns, HCO+, and CO pure rotational lines all arise from the outer disk at r approx. 30-120 AU. We discuss planet formation and photoevaporation as causes for the decrease in surface density of gas and dust inside 4 AU. If a planet is present, our results suggest a planet mass approx. 4-7MJ situated at 3 AU. Using our photoevaporation models and the best surface density profile match to observations, we estimate a current photoevaporative mass loss rate of 4x10(exp -9M)/yr and a remaining disk lifetime of approx.5 million years.

  9. Intensity of Hydrogen Line Emission from Accreting Gas-Giant Planets

    NASA Astrophysics Data System (ADS)

    Aoyama, Yuhiko; Tanigawa, Takayuki; Ikoma, Masahiro

    2015-12-01

    Planets have been thought to form in circumstellar gaseous disks. Indeed, a number of young stars surrounded by such disks have been already detected. Recently, there are some reports on detection of gap-like structure in circumstellar disks, which suggests that there are forming massive protoplanets embedded in the disks. A challenging issue is how to find forming planets in circumstellar disks directly. In this study, we investigate whether detectable emission occurs from accreting gas-giant planets. In a circumstellar disk, once a solid core becomes massive enough, it captures the surrounding disk gas gravitationally in a runaway manner. Since the disk gas accretion occurs much faster than angular momentum loss, a circumplanetary disk is formed in the mid-plane of the circumstellar disk. Recent three-dimensional hydrodynamic simulations by Tanigawa et al. (2012) revealed that the gas flowed from the cicumstellar disk to the circumplanetary disk not horizontally but vertically. According to those simulations, the disk gas falls onto the circumplanetary disk at a speed comparable to the free fall speed, and the local gas temperature reaches up to tens of thousands of kelvin because of shock heating near the planet. Thus, the presence of an accreting gas giant planet may be found by observation of the radiative emission from such hot gas in the circumplanetary disk, which we quantify in this study. In particular, we focus on the intensity of line emission from hydrogen. We have simulated the post-shock gas flow with non-equilibrium chemical reaction and electron transition. Then, we have found that the intensity of some hydrogen lines is proportional to the number density of the surrounding circumstellar disk gas and square of the planet mass, so the protoplanet’s hydrogen-line emission is less intense by a few orders of magnitude relative to the protostar’s emission under some realistic conditions. Also, the duration time is comparable to the dissipation time

  10. The Ultimate Emission Line Diagnostics Study at z=1.4

    NASA Astrophysics Data System (ADS)

    Rigby, Jane

    2015-10-01

    We propose the ultimate WFC3 grism spectroscopy, in terms of spatial resolution, signal-to-noise ratio, and diagnostic emission line coverage, at z=1.4. The targets are two extremely bright lensed galaxies at redshifts of 1.329 and 1.420. These redshifts place all of rest-frame optical diagnostic emission lines, from [O II] 3727 to [S II] 6731 A, in the WFC3 G102 and G141 grisms. On spatial scales down to 100~pc, we will map the star formation rate, metallicity, extinction, and excitation across these two galaxies, and thereby measure not only the physical conditions of star formation, but how those conditions vary spatially. For the target that currently lacks HST and Spitzer imaging, we propose 2 orbits of WFC3/UVIS imaging to enable creation of a lensing map, and 1~hr of Spitzer to obtain a stellar mass estimate. This program will be a legacy for HST, the most rigorous in situ test yet of strong-line nebular line diagnostics in the distant universe, and will establish a benchmark for far larger grism surveys in which HST has invested some 700 orbits.

  11. Global Galactic distribution of the 1.275 MeV γ-ray line emission

    NASA Astrophysics Data System (ADS)

    Iyudin, A. F.; Bennett, K.; Lichti, G. G.; Ryan, J.; Schönfelder, V.

    2005-11-01

    We present results of the analysis of 1.275 MeV γ-ray line global distribution derived from the all-sky data accumulated by COMPTEL on board the Compton Gamma Ray Observatory (CGRO) from 1991 to 1997. Previously the 1.275 MeV γ-ray line was believed to be largely produced in the decay of radioactive isotope 22Na that is synthesised in the classical nova (CN) thermonuclear runaway (TNR). Another way to produce the 1.275 MeV line emission is via the excitation of 22Ne-nuclei, e.g. through the low-energy cosmic ray interactions with the nuclei of the interstellar matter that lead to the production of 22Ne^*, or of 22Na. This scenario, as we now believe, can be dominant in contributing to the total 1.275 MeV γ-ray line emission from the galactic bulge. Unfortunately, systematic uncertainties in the analysis of the COMPTEL data hinder a clear distinction between two alternative scenarios.

  12. Origin and dynamics of emission line clouds in cooling flow environments

    NASA Technical Reports Server (NTRS)

    Loewenstein, Michael

    1990-01-01

    The author suggests that since clouds are born co-moving in a turbulent intra-cluster medium (ICM), the allowed parameter space can now be opened up to a more acceptable range. Large-scale motions can be driven in the central parts of cooling flows by a number of mechanisms including the motion of the central and other galaxies, and the dissipation of advected, focussed rotational and magnetic energy. In addition to the velocity width paradox, two other paradoxes (Heckman et al. 1989) can be solved if the ICM is turbulent. Firstly, the heating source for the emission line regions has always been puzzling - line luminosities are extremely high for a given (optical or radio) galaxy luminosity compared to those in non-cooling flow galaxies, therefore a mechanism peculiar to cooling flows must be at work. However most, if not all, previously suggested heating mechanisms either fail to provide enough ionization or give the wrong line ratios, or both. The kinetic energy in the turbulence provides a natural energy source if it can be efficiently converted to cloud heat. Researchers suggest that this can be done via magneto-hydrodynamic waves through plasma slip. Secondly, while the x ray observations indicate extended mass deposition, the optical line emission is more centrally concentrated. Since many of the turbulence-inducing mechanisms are strongest in the central regions of the ICM, so is the method of heating. In other words material is dropping out everywhere but only being lit up in the center.

  13. 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

    2002-04-02

    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.

  14. 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

  15. A New Method for Modeling Optical Depth Effects in Cometary Emission Lines

    NASA Astrophysics Data System (ADS)

    Gersch, Alan; A'Hearn, M. F.

    2008-09-01

    We create a model of the carbon monoxide IR spectra of a cometary coma including optical depth effects using Coupled Escape Probability (CEP), a new exact method for line radiative transfer solutions (see Elitzur & Asensio Ramos, 2005). In the CEP method a plane parallel atmosphere is divided into vertical "zones". Each zone's distribution of fractional populations in molecular energy levels is determined using statistical equilibrium. All the zones are coupled through terms resembling escape probability expressions, which encapsulate the self-radiation due to scattering and absorption between zones. This enables a self-consistent solution for the line radiation produced even in optically thick cases. We have implemented the CEP approach to calculate the line emission of the CO IR 1-0 ro-vibrational spectra, for arbitrary conditions such as those found in cometary comae. The coma itself is modeled using numerical integration of the expanding coma gas from the nucleus outwards (see, e.g. Chin & Weaver, 1984.) Our model of the coma uses the CEP method for integrating CO emission throughout the coma in a piecewise manner which yields a model spectra for any observed line of sight through the coma. We have constructed spectral "maps" of the coma of comet Tempel-1 in various frequencies, corresponding to observations during the approach and impact of the Deep Impact mission. These are compared with the actual Deep Impact observations to better understand the coma composition.

  16. Hubble space telescope emission line galaxies at z ∼ 2: the Lyα escape fraction

    SciTech Connect

    Ciardullo, Robin; Zeimann, Gregory R.; Gronwall, Caryl; Gebhardt, Henry; Schneider, Donald P.; Hagen, Alex; Malz, A. I. E-mail: grzeimann@psu.edu E-mail: gebhardt@psu.edu E-mail: hagen@psu.edu; and others

    2014-11-20

    We compare the Hβ line strengths of 1.90 < z < 2.35 star-forming galaxies observed with the near-IR grism of the Hubble Space Telescope with ground-based measurements of Lyα from the HETDEX Pilot Survey and narrow-band imaging. By examining the line ratios of 73 galaxies, we show that most star-forming systems at this epoch have a Lyα escape fraction below ∼6%. We confirm this result by using stellar reddening to estimate the effective logarithmic extinction of the Hβ emission line (c {sub Hβ} = 0.5) and measuring both the Hβ and Lyα luminosity functions in a ∼100, 000 Mpc{sup 3} volume of space. We show that in our redshift window, the volumetric Lyα escape fraction is at most 4.4{sub −1.2}{sup +2.1}%, with an additional systematic ∼25% uncertainty associated with our estimate of extinction. Finally, we demonstrate that the bulk of the epoch's star-forming galaxies have Lyα emission line optical depths that are significantly greater than that for the underlying UV continuum. In our predominantly [O III] λ5007-selected sample of galaxies, resonant scattering must be important for the escape of Lyα photons.

  17. CONSTRAINING THE MILKY WAY'S HOT GAS HALO WITH O VII AND O VIII EMISSION LINES

    SciTech Connect

    Miller, Matthew J.; Bregman, Joel N. E-mail: jbregman@umich.edu

    2015-02-10

    The Milky Way hosts a hot (≈2 × 10{sup 6} K), diffuse, gaseous halo based on detections of z = 0 O VII and O VIII absorption lines in quasar spectra and emission lines in blank-sky spectra. Here we improve constraints on the structure of the hot gas halo by fitting a radial model to a much larger sample of O VII and O VIII emission line measurements from XMM-Newton/EPIC-MOS spectra compared to previous studies (≈650 sightlines). We assume a modified β-model for the halo density distribution and a constant-density Local Bubble from which we calculate emission to compare with the observations. We find an acceptable fit to the O VIII emission line observations with χ{sub red}{sup 2} (dof) = 1.08 (644) for best-fit parameters of n{sub o}r{sub c}{sup 3β}=1.35±0.24 cm{sup –3} kpc{sup 3β} and β = 0.50 ± 0.03 for the hot gas halo and negligible Local Bubble contribution. The O VII observations yield an unacceptable χ{sub red}{sup 2} (dof) = 4.69 (645) for similar best-fit parameters, which is likely due to temperature or density variations in the Local Bubble. The O VIII fitting results imply hot gas masses of M(<50 kpc) = 3.8{sub −0.3}{sup +0.3}×10{sup 9} M{sub ⊙} and M(<250 kpc) = 4.3{sub −0.8}{sup +0.9}×10{sup 10} M{sub ⊙}, accounting for ≲50% of the Milky Way's missing baryons. We also explore our results in the context of optical depth effects in the halo gas, the halo gas cooling properties, temperature and entropy gradients in the halo gas, and the gas metallicity distribution. The combination of absorption and emission line analyses implies a sub-solar gas metallicity that decreases with radius, but that also must be ≥0.3 Z {sub ☉} to be consistent with the pulsar dispersion measure toward the Large Magellanic Cloud.

  18. Fraction of the X-ray selected AGNs with optical emission lines in galaxy groups

    NASA Astrophysics Data System (ADS)

    Li, Feng; Yuan, Qirong; Bian, Weihao; Chen, Xi; Yan, Pengfei

    2017-04-01

    Compared with numerous X-ray dominant active galactic nuclei (AGNs) without emission-line signatures in their optical spectra, the X-ray selected AGNs with optical emission lines are probably still in the high-accretion phase of black hole growth. This paper presents an investigation on the fraction of these X-ray detected AGNs with optical emission-line spectra in 198 galaxy groups at z<1 in a rest frame 0.1-2.4 keV luminosity range 41.3 < log(LX/erg s^{-1}) < 44.1 within the Cosmological Evolution Survey (COSMOS) field, as well as its variations with redshift and group richness. For various selection criteria of member galaxies, the numbers of galaxies and the AGNs with optical emission lines in each galaxy group are obtained. It is found that, in total 198 X-ray groups, there are 27 AGNs detected in 26 groups. AGN fraction is on average less than 4.6 (±1.2)% for individual groups hosting at least one AGN. The corrected overall AGN fraction for whole group sample is less than 0.98 (±0.11) %. The normalized locations of group AGNs show that 15 AGNs are found to be located in group centers, including all 6 low-luminosity group AGNs (L_{ 0.5-2 keV} < 10^{42.5} erg s^{-1}). A week rising tendency with z are found: overall AGN fraction is 0.30-0.43% for the groups at z<0.5, and 0.55-0.64% at 0.5 < z < 1.0. For the X-ray groups at z>0.5, most member AGNs are X-ray bright, optically dull, which results in a lower AGN fractions at higher redshifts. The AGN fraction in isolated fields also exhibits a rising trend with redshift, and the slope is consistent with that in groups. The environment of galaxy groups seems to make no difference in detection probability of the AGNs with emission lines. Additionally, a larger AGN fractions are found in poorer groups, which implies that the AGNs in poor groups might still be in the high-accretion phase, whereas the AGN population in rich clusters is mostly in the low-accretion, X-ray dominant phase.

  19. Empirically Constrained Predictions for Metal-line Emission from the Circumgalactic Medium

    NASA Astrophysics Data System (ADS)

    Corlies, Lauren; Schiminovich, David

    2016-08-01

    The circumgalactic medium (CGM) is one of the remaining least constrained components of galaxies and as such has significant potential for advancing galaxy formation theories. In this work, we vary the extragalactic ultraviolet background for a high-resolution cosmological simulation of a Milky-Way-like galaxy and examine the effect on the absorption and emission properties of metals in the CGM. We find that a reduced quasar background brings the column density predictions into better agreement with recent data. Similarly, when the observationally derived physical properties of the gas are compared to the simulation, we find that the simulation gas is always at temperatures approximately 0.5 dex higher. Thus, similar column densities can be produced from fundamentally different gas. However, emission maps can provide complementary information to the line-of-sight column densities to better derive gas properties. From the simulations, we find that the brightest emission is less sensitive to the extragalactic background and that it closely follows the fundamental filamentary structure of the halo. This becomes increasingly true as the galaxy evolves from z = 1 to z = 0 and the majority of the gas transitions to a hotter, more diffuse phase. For the brightest ions (C iii, C iv, O vi), detectable emission can extend as far as 120 kpc at z = 0. Finally, resolution is a limiting factor for the conclusions we can draw from emission observations, but with moderate resolution and reasonable detection limits, upcoming instrumentation should place constraints on the physical properties of the CGM.

  20. A Link Between X-ray Emission Lines and Radio Jets in 4U 1630-47?

    NASA Astrophysics Data System (ADS)

    Neilsen, Joseph; Coriat, Mickaël; Fender, Rob; Lee, Julia C.; Ponti, Gabriele; Tzioumis, A.; Edwards, Phillip; Broderick, Jess

    2014-06-01

    Recently, Díaz Trigo et al. reported an XMM-Newton detection of relativistically Doppler-shifted emission lines associated with steep-spectrum radio emission in the stellar-mass black hole candidate 4U 1630-47 during its 2012 outburst. They interpreted these lines as indicative of a baryonic jet launched by the accretion disk. We present a search for the same lines earlier in the same outburst using high-resolution X-ray spectra from the Chandra HETGS. While our observations (eight months prior to the XMM-Newton campaign) also coincide with detections of steep spectrum radio emission by the Australia Telescope Compact Array, we find a strong disk wind but no evidence for any relativistic X-ray emission lines. Indeed, despite ˜5× brighter radio emission, our Chandra spectra allow us to place an upper limit on the flux in the blueshifted Fe XXVI line that is ˜20× weaker than the line observed by Díaz Trigo et al. Thus we can conclusively say that radio emission is not universally associated with relativistically Doppler-shifted emission lines in 4U 1630-47. We explore several scenarios that could explain our differing results, including variations in the geometry of the jet or a mass-loading process or jet baryon content that evolves with the accretion state of the black hole. We also consider the possibility that the radio emission arises in an interaction between a jet and the nearby ISM, in which case the X-ray emission lines might be unrelated to the radio emission.

  1. Identification of the ~3.55 keV emission line candidate objects across the sky

    NASA Astrophysics Data System (ADS)

    Savchenko, D. O.; Iakubovskyi, D. A.

    2015-12-01

    An emission line at the energy ~3.55 keV detected in different galaxies and galaxy clusters has caused numerous discussions in high-energy astrophysics and particle physics communities. To reveal the origin of the line, we analyzed publicly-available observations of MOS cameras from XMM-Newton cosmic observatory - the instrument with the largest sensitivity for narrow faint X-ray lines - previously combined in X-ray sky maps. Because an extremely large timescale is needed for detailed analysis, we used the wavelet method instead. Extensive simulations of the central part of the Andromeda galaxy are used to check the validity of this method. The resulting list of wavelet detections now contains 235 sky regions. This list will be used in future works for more detailed spectral analysis.

  2. A spectroscopic study of the DR 21 outflow source. II. The vibrational H2 line emission

    SciTech Connect

    Garden, R.P.; Geballe, T.R.; Gatley, I.; Nadeau, D. Joint Astronomy Center, Hilo, HI National Optical Astronomy Observatories, Tucson, AZ Montreal Universite, Montreal )

    1991-01-01

    Large-scale mapping and high-spectral-resolution profile measurements of the vibrational H2 v = 1-0 S(1) line are used to investigate the morphology and kinematic structure of the hot, shocked gas associated with the ultraluminous DR 21 young-stellar outflow. It is found that the H2 line profiles at certain locations within the outflow possess high-velocity wings which extend to beyond 100 km/s from the DR 21 rest velocity. It is argued that the jets, which shock the surrounding molecular cloud medium and produce the bright H2-line emission, are composed primarily of hot atomic gas which is confined by the thermal pressure of the ambient cloud medium. 37 refs.

  3. Some Considerations about Inferring Coronal Magnetic Fields and Other Coronal Properties from Coronal Emission Line Polarization

    NASA Astrophysics Data System (ADS)

    Arnaud, J.; Habbal, S. R.; Arndt, M.; Woo, R.

    2003-12-01

    Ground based studies of Coronal Emission Lines (CEL) linear polarization had been carried out for the 530.3 nm FeXIV line at Pic du Midi and for the 1074.7 nm Fe XIII line at Sac Peak in the 1977-1980 period. The large scale organization of the polarization has clearly revealed the existence of a large scale structure of the coronal magnetic field. More recently, the first successful eclipse CEL polarimetric measurements were made in the 1074.7 nm line during the total solar eclipse of 21 June 2001, confirming earlier results of the predominance of a radial direction of the coronal magnetic field. A first measurement of the circular polarization in the 1074.7 nm line has also recently been performed. Circular polarization gives access to the strength of the LOS magnetic field while the linear polarization maps the transverse magnetic field direction. We will use ground based and eclipse 1074.7 nm line polarimetric data to provide examples of the properties (e.g., magnetic field, abundances, inhomogeneities) such observations can help to infer in this 3-D and optically thin medium.

  4. IMPROVED AND QUALITY-ASSESSED EMISSION AND ABSORPTION LINE MEASUREMENTS IN SLOAN DIGITAL SKY SURVEY GALAXIES

    SciTech Connect

    Oh, Kyuseok; Yi, Sukyoung K.; Sarzi, Marc; Schawinski, Kevin

    2011-08-01

    We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionized gas emission. In order to check for systematic departures from the rather standard set of assumptions that enters our models, we provide a quality assessment for our fit to the SDSS spectra in our sample, for both the stellar continuum and the nebular emissions and across different wavelength regions. This quality assessment also allows the identification of objects with either problematic data or peculiar features. We hope to foster the discovery potential of our database; therefore, our spectral fit is available to the community. For example, based on the quality assessment around the H{alpha} and [N II] {lambda}6584 lines, approximately 1% of the SDSS spectra classified as 'galaxies' by the SDSS pipeline do in fact require additional broad lines to be matched, even though they do not show a strong continuum from an active

  5. The MUSE-Wide survey: A first catalogue of 831 emission line galaxies

    NASA Astrophysics Data System (ADS)

    Herenz, Edmund Christian; Urrutia, Tanya; Wisotzki, Lutz; Kerutt, Josephine; Saust, Rikke; Werhahn, Maria; Schmidt, Kasper Borello; Caruana, Joseph; Diener, Catrina; Bacon, Roland; Brinchmann, Jarle; Schaye, Joop; Maseda, Michael; Weilbacher, Peter M.

    2017-09-01

    We present a first instalment of the MUSE-Wide survey, covering an area of 22.2 arcmin2 (corresponding to 20% of the final survey) in the CANDELS/Deep area of the Chandra Deep Field South. We use the MUSE integral field spectrograph at the ESO VLT to conduct a full-area spectroscopic mapping at a depth of 1 h exposure time per 1 arcmin2 pointing. We searched for compact emission line objects using our newly developed LSDCat software based on a 3D matched filtering approach, followed by interactive classification and redshift measurement of the sources. Our catalogue contains 831 distinct emission line galaxies with redshifts ranging from 0.04 to 6. Roughly one third (237) of the emission line sources are Lyman α emitting galaxies with 3 < z < 6, only four of which had previously measured spectroscopic redshifts. At lower redshifts 351 galaxies are detected primarily by their [O ii] emission line (0.3 ≲ z ≲ 1.5), 189 by their [O iii] line (0.21 ≲ z ≲ 0.85), and 46 by their Hα line (0.04 ≲ z ≲ 0.42). Comparing our spectroscopic redshifts to photometric redshift estimates from the literature, we find excellent agreement for z < 1.5 with a median Δz of only 4 × 10-4 and an outlier rate of 6%, however a significant systematic offset of Δz = 0.26 and an outlier rate of 23% for Lyα emitters at z > 3. Together with the catalogue we also release 1D PSF-weighted extracted spectra and small 3D datacubes centred on each of the 831 sources. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 094.A-0205.Data products are available via http://muse-vlt.eu/science/ and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A12 .

  6. Improved and Quality-assessed Emission and Absorption Line Measurements in Sloan Digital Sky Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Oh, Kyuseok; Sarzi, Marc; Schawinski, Kevin; Yi, Sukyoung K.

    2011-08-01

    We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionized gas emission. In order to check for systematic departures from the rather standard set of assumptions that enters our models, we provide a quality assessment for our fit to the SDSS spectra in our sample, for both the stellar continuum and the nebular emissions and across different wavelength regions. This quality assessment also allows the identification of objects with either problematic data or peculiar features. We hope to foster the discovery potential of our database; therefore, our spectral fit is available to the community. For example, based on the quality assessment around the Hα and [N II] λ6584 lines, approximately 1% of the SDSS spectra classified as "galaxies" by the SDSS pipeline do in fact require additional broad lines to be matched, even though they do not show a strong continuum from an active nucleus, as

  7. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Astrophysics Data System (ADS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E.; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; Stern, Daniel; Treu, Tommaso; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Brewer, Brendon J.; Cenko, S. Bradley; Clubb, Kelsey I.; Cooper, Michael C.; Diamond-Stanic, Aleksandar M.; Hiner, Kyle D.; Hönig, Sebastian F.; Hsiao, Eric; Kandrashoff, Michael T.; Lazarova, Mariana S.; Nierenberg, A. M.; Rex, Jacob; Silverman, Jeffrey M.; Tollerud, Erik J.; Walsh, Jonelle L.

    2015-04-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ˜250 km s-1 over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  8. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Technical Reports Server (NTRS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E..; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; hide

    2016-01-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hß line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H beta line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H beta width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H beta velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H beta velocity shifted by approximately 250 km s(exp -1) over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  9. THE LICK AGN MONITORING PROJECT 2011: SPECTROSCOPIC CAMPAIGN AND EMISSION-LINE LIGHT CURVES

    SciTech Connect

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Li, Weidong; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Treu, Tommaso; Pancoast, Anna; Sand, David J.; Stern, Daniel; Woo, Jong-Hak; Assef, Roberto J.; Bae, Hyun-Jin; Brewer, Brendon J.; Cenko, S. Bradley; and others

    2015-04-15

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hβ line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad Hβ line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad Hβ width and luminosity, demonstrating that the broad-line region “breathes” on short timescales of days to weeks in response to continuum variations. We also find that broad Hβ velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad Hβ velocity shifted by ∼250 km s{sup −1} over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  10. The Lick AGN Monitoring Project 2011: Spectroscopic Campaign and Emission-line Light Curves

    NASA Technical Reports Server (NTRS)

    Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Gates, Elinor L.; Greene, Jenny E..; Li, Weidong; Malkan, Matthew A.; Pancoast, Anna; Sand, David J.; Stern, Daniel; Cenko, S. Bradley

    2016-01-01

    In the Spring of 2011 we carried out a 2.5 month reverberation mapping campaign using the 3 m Shane telescope at Lick Observatory, monitoring 15 low-redshift Seyfert 1 galaxies. This paper describes the observations, reductions and measurements, and data products from the spectroscopic campaign. The reduced spectra were fitted with a multicomponent model in order to isolate the contributions of various continuum and emission-line components. We present light curves of broad emission lines and the active galactic nucleus (AGN) continuum, and measurements of the broad Hß line widths in mean and rms spectra. For the most highly variable AGNs we also measured broad H beta line widths and velocity centroids from the nightly spectra. In four AGNs exhibiting the highest variability amplitudes, we detect anticorrelations between broad H beta width and luminosity, demonstrating that the broad-line region "breathes" on short timescales of days to weeks in response to continuum variations. We also find that broad H beta velocity centroids can undergo substantial changes in response to continuum variations; in NGC 4593, the broad H beta velocity shifted by approximately 250 km s(exp -1) over a 1 month period. This reverberation-induced velocity shift effect is likely to contribute a significant source of confusion noise to binary black hole searches that use multi-epoch quasar spectroscopy to detect binary orbital motion. We also present results from simulations that examine biases that can occur in measurement of broad-line widths from rms spectra due to the contributions of continuum variations and photon-counting noise.

  11. Unidentified emission lines in comets: recognition and implementation in the comet lines tool at the IDIS Small Bodies and Dust Node

    NASA Astrophysics Data System (ADS)

    Braga, V. F.; Giardino, M.; Capria, M. T.; De Sanctis, M. C.

    2012-09-01

    Unidentified lines of five comets from four cometary emission lines catalogs (23P/Brorsen-Metcalf [1], 109P/Swift-Tuttle [1], 122P/De Vico [2], 153P/Ikeya- Zhang [3] and C/1995 O1 Hale-Bopp [5]) are the subject of this work. These lines are all included in the database of the comet lines tool at the IDIS Small Bodies and Dust Node (SBDN). An objective criterium to recognize which unidentified lines could be considered to be spectral marks of the same transition in different comets is established.

  12. Evolution of Emission Line Galaxies from z<0.5 to the present

    NASA Astrophysics Data System (ADS)

    Horowitz, I. K.; Schmidt, M.; Schneider, D. P.

    1993-05-01

    A comparison of the predicted and observed number counts of two samples of emission line galaxies is made so as to determine the extent to which evolutionary effects play a role in these objects from z<0.5 to the present. The distant sample of objects is taken from the 4-Shooter transit surveys of Schmidt, Schneider and Gunn (hereafter SSG). It consists of 371 galaxies whose inclusion by SSG was based on the detection of either the Hβ 4861 or the [OIII]lambda lambda 4959,5007 emission line. The nearby sample is taken from the CfA Northern Sky Redshift Survey (Davis, et.al., 1983). From the work of Burg (1987), a subset of 81 galaxies with strong [OIII] emission (EW>25 Angstroms) has been selected. Added to that list are 26 additional Seyfert galaxies from Edelson (1987). This group of 107 CfA galaxies represents an initial sample that has been observed on the 1.5m Oscar Meyer telescope at Palomar Observatory using the Echelle Spectrograph, which was operated in a low-resolution mode. Spectra were taken along both the major and minor axes of each CfA galaxy. The data were analyzed so as to determine how each galaxy would appear in the transit survey as a function of redshift. Having determined the maximum observable redshift for each CfA galaxy, based on the transit survey criteria, a prediction is made of the number of similar galaxies expected in the transit survey through a comparison of the accessible volumes in both the CfA survey as well as the transit survey. This is then compared to the observed numbers of galaxies in the transit survey, and a statement is made on the effects of evolution on various sub-classes of emission line galaxies.

  13. Origin of the Galactic Disk 6.7 kev Line Emission

    NASA Technical Reports Server (NTRS)

    Churchwell, Ed

    1997-01-01

    The goal of this program was to determine if the extended FeXXV 6.7 kev line emission might possibly be produced and confined by the hot wind-shocked bubbles to accompany UC HII regions. The main result of this study are: (1) FeXXV is detected in the W3 complex, but at a level that could only explain a small fraction of the galactic disk emission if all UC HII regions emit at about the same intensity as the W3 complex; (2) Two X-ray sources are detected in W3. W3-X 1 coincides with the radio image of this region, but W3-X2 has no radio, optical, or infrared counterpart; (3) There is no evidence for variability of W3-X1 during the period of observations (approx, 40,000 sec); (4) The X-ray spectrum of W3-X1 has no emission shortward of 1 kev, it peaks at approx. 2 kev and show significant emission out to approx. 6 kev. No individual lines are resolved. There is currently no generally accepted theory for extended hard X-ray emission in HII regions. Perhaps the most significant discovery of this program has been the detection of extended hard X-rays and the realization that some entirely new processes must be invoked to understand this; and (5)A minimum (chi)(sup 2) fit of the spectrum implies a H absorbing column of N(sub H) approx, equals to 2.1 x 10(exp 22)/ cm, a temperature of the emitting plasma of 7 x 10(exp 7) K, and a luminosity of approx. equal to 10(33)erg/s.

  14. The evolution of emission lines in massive early-type red galaxies

    NASA Astrophysics Data System (ADS)

    Konidaris, Nicholas Pelopidas, II

    2008-12-01

    This thesis performs a look-back study on the forbidden [O II ] l3727 Å emission line in massive early-type red galaxies (MERGs) at z ~ 0.1 and z ~ 0.8. At z ~ 0, MERGs show young stellar populations. By looking back in time, at z ~ 0.8 MERGs it is possible to find signs of these young stars being formed. It is commonly thought, that [O II] luminosity traces the star formation rate; however, for z ~ 0.1 and z ~ 0.8 MERGs this is largely not the case. A variety of techniques are brought to bear on this issue. First, the evolution of the average [O II] luminosity density in MERGs from z ~ 0.8 to z ~ 0.1is (1 + z) ~1-2 , which evolves less than the global evolution of star formation of (1 + z) 4 . Second, a new star formation diagnostic is created based on line ratios. Ideally, our z ~ 0.8 MERG spectra would allow us to create a full diagnostic diagram (Ha/[NII] versus [O III]/Hb). Instead of using Ha, which is redshifted out of the visible, out new technique is calibrated on mass, color, and the emission line [O III]/Hb ratio in z ~ 0.1 massive red galaxies. The z ~ 0.8 MERGs are similar in mass, color, and [O III]/Hb ratio to the z ~ 0.1 massive red galaxies that are not forming stars. Third, the [O II] emission line is found to be physically extended in a deeply observed sample of z ~ 0.8 MERGs, suggesting that [O II] is produced by both nuclear and extended sources. In conclusion, I argue that the young stellar populations found in local MERGs are produced either by the continual addition of galaxies with young stars added to the MERG population. Or if they are form in the MERGs themselves, are formed during rare bursts.

  15. Microlensing Constraints on Broad Absorption and Emission Line Flows in the Quasar H1413+117

    NASA Astrophysics Data System (ADS)

    O'Dowd, Matthew J.; Bate, Nicholas F.; Webster, Rachel L.; Labrie, Kathleen; Rogers, Joshua

    2015-11-01

    We present new integral field spectroscopy of the gravitationally lensed broad absorption line (BAL) quasar H1413+117, covering the ultraviolet restframe spectral range. We observe strong microlensing signatures in lensed image D, and we use this microlensing to simultaneously constrain both the broad emission and broad absorption line gas. The wavelength independence of image D magnifications across the broad emission lines (BELs) indicates a lower limit on the broad emission line region (BELR) size equal to the Einstein radius (ER) of the system: ≳11 {(< M> /{M}⊙ )}0.5 lt-day for a lens redshift of 1.4 and ≳15 {(< M> /{M}⊙ )}0.5 lt-day for zL = 0.94. Lensing simulations verify that the observed wavelength independence is very unlikely for BELRs with significant velocity stratification at size scales below an ER. We perform spectral decomposition to derive the intrinsic BEL and continuum spectrum, subject to BAL absorption. We reconstruct the intrinsic BAL absorption profile, whose features allow us to constrain outflow kinematics in the context of a disk-wind model. We find a very sharp, blueshifted onset of absorption of 1500 km s-1 in both C iv and N v, which may correspond to an inner edge of a disk-wind’s radial outflow. The lower ionization Si iv and Al iii have higher-velocity absorption onsets, consistent with a decreasing ionization parameter with radius in an accelerating outflow. There is evidence of strong absorption in the BEL component, which indicates a high covering factor for absorption over two orders of magnitude in outflow radius.

  16. Emission Line Properties of Seyfert Galaxies in the 12 μm Sample

    NASA Astrophysics Data System (ADS)

    Malkan, Matthew A.; Jensen, Lisbeth D.; Rodriguez, David R.; Spinoglio, Luigi; Rush, Brian

    2017-09-01

    We present optical and ultraviolet spectroscopic measurements of the emission lines of 81 Seyfert 1 and 104 Seyfert 2 galaxies that comprise nearly all of the IRAS 12 μm AGN sample. We have analyzed the emission-line luminosity functions, reddening, and other diagnostics. For example, the narrow-line regions (NLR) of Seyfert 1 and 2 galaxies do not significantly differ from each other in most of these diagnostics. Combining the Hα/Hβ ratio with a new reddening indicator—the [S ii]6720/[O ii]3727 ratio—we find the average E(B–V) is 0.49 ± 0.35 for type 1 and 0.52 ± 0.26 for type 2 Seyferts. The NLR of Sy 1s has an ionization level insignificantly higher than that of Sy 2s. For the broad-line region (BLR), we find that the C iv equivalent width correlates more strongly with [O iii]/Hβ than with UV luminosity. Our bright sample of local active galaxies includes 22 Seyfert nuclei with extremely weak broad wings in Hα, known as Seyfert 1.9s and 1.8s, depending on whether or not broad Hβ wings are detected. Aside from these weak broad lines, our low-luminosity Seyferts are more similar to the Sy 2s than to Sy 1s. In a BPT diagram, we find that Sy 1.8s and 1.9s overlap the region occupied by Sy 2s. We compare our results on optical emission lines with those obtained by previous investigators, using AGN subsamples from the Sloan Digital Sky Survey. The luminosity functions of forbidden emission lines [O ii]λ3727 Å, [O iii]λ5007 Å, and [S ii]λ6720 Å in Sy 1s and Sy 2s are indistinguishable. They all show strong downward curvature. Unlike the LFs of Seyfert galaxies measured by the Sloan Digital Sky Survey, ours are nearly flat at low luminosities. The larger number of faint Sloan “AGN” is attributable to their inclusion of weakly emitting LINERs and H ii+AGN “composite” nuclei, which do not meet our spectral classification criteria for Seyferts. In an Appendix, we have investigated which emission line luminosities can provide the most reliable

  17. SIMULTANEOUS ULTRAVIOLET AND OPTICAL EMISSION-LINE PROFILES OF QUASARS: IMPLICATIONS FOR BLACK HOLE MASS DETERMINATION

    SciTech Connect

    Ho, Luis C.; Dong Xiaobo; Goldoni, Paolo; Ponti, Gabriele; Greene, Jenny E.

    2012-07-20

    The X-shooter instrument on the Very Large Telescope was used to obtain spectra of seven moderate-redshift quasars simultaneously covering the spectral range {approx}3000 A to 2.5 {mu}m. At z Almost-Equal-To 1.5, most of the prominent broad emission lines in the ultraviolet to optical region are captured in their rest frame. We use this unique data set, which mitigates complications from source variability, to intercompare the line profiles of C IV {lambda}1549, C III] {lambda}1909, Mg II {lambda}2800, and H{alpha} and evaluate their implications for black hole (BH) mass estimation. We confirm that Mg II and the Balmer lines share similar kinematics and that they deliver mutually consistent BH mass estimates with minimal internal scatter ({approx}<0.1 dex) using the latest virial mass estimators. Although no virial mass formalism has yet been calibrated for C III], this line does not appear promising for such an application because of the large spread of its velocity width compared to lines of both higher and lower ionization; part of the discrepancy may be due to the difficulty of deblending C III] from its neighboring lines. The situation for C IV is complex and, because of the limited statistics of our small sample, inconclusive. On the one hand, slightly more than half of our sample (4/7) have C IV line widths that correlate reasonably well with H{alpha} line widths, and their respective BH mass estimates agree to within {approx}0.15 dex. The rest, on the other hand, exhibit exceptionally broad C IV profiles that overestimate virial masses by factors of 2-5 compared to H{alpha}. As C IV is widely used to study BH demographics at high redshifts, we urgently need to revisit our analysis with a larger sample.

  18. Is CO radio line emission a reliable mass-loss-rate estimator for AGB stars?

    NASA Astrophysics Data System (ADS)

    Ramstedt, Sofia; Scḧier, Frederik; Olofsson, Hans

    The final evolutionary stage of low- to intermediate-mass stars, as they evolve along the asymptotic giant branch (AGB), is characterized by mass loss so intense (10-8-10-4 Msol yr-1) that eventually the AGB life time is determined by it. The material lost by the star is enriched in nucleo-synthesized material and thus AGB stars play an important role in the chemical evolution of galaxies. A reliable mass-loss-rate estimator is of utmost importance in order to increase our understanding of late stellar evolution and to reach conclusions about the amount of enriched material recycled by AGB stars. For low-mass-loss-rate AGB stars, modelling of observed rotational CO radio line emission has proven to be a good tool for estimating mass-loss rates [Olofsson et al. (2002) for M-type stars and Schöier & Olofsson (2001) for carbon stars], but several lines are needed to get good constraints. For high-mass-loss-rate objects the situation is more complicated, the main reason being saturation of the optically thick CO lines. Moreover, Kemper et al. (2003) introduced temporal changes in the mass-loss rate, or alternatively, spatially varying turbulent motions, in order to explain observed line-intensity ratios. This puts into question whether it is possible to model the circumstellar envelope using a constant mass-loss rate, or whether the physical structure of the outflow is more complex than normally assumed. We present observations of CO radio line emission for a sample of intermediate- to high-mass-loss-rate AGB stars. The lowest rotational transition line (J =1-0) was observed at OSO and the higher-frequency lines (J =2-1, 3-2, 4-3 and in some cases 6-5) were observed at the JCMT. Using a detailed, non-LTE, radiative transfer model we are able to reproduce observed line ratios (Figure 1) and constrain the mass-loss rates for the whole sample, using a constant mass-loss rate and a "standard" circumstellar envelope model. However, for some objects only a lower limit to

  19. Emission-Line Properties and Selection Effects for z > 4 Quasars

    NASA Astrophysics Data System (ADS)

    Constantin, A.; Shields, J. C.; Hamann, F.

    2000-12-01

    A growing number of QSOs are now known to exist at redshifts beyond 4, and these sources provide important opportunities for better understanding of the astrophysics of galaxy formation and evolution. To date there are ~ 130 known QSOs with z > 4, but only limited efforts have been made to survey systematically the emission-line properties of these objects and/or the selection effects related with the techniques by which they were discovered. In this poster we will present results of a program of high signal-to-noise spectroscopy for 44 QSOs using the MMT and Keck observatories. The majority of these sources were originally identified via color selection techiques. The quasar spectra cover wavelengths between 1100 Å and 1700 Å in the rest frame, for sources spanning a luminosity range of ~ 2 orders of magnitude. An examination of the luminosity dependence of the emission features reveals evidence for a weak Baldwin effect. Spectrum composites for the whole data set and for subsets are obtained and analysed in order to investigate the spectral dependence on selection effects. The results show a tendency for stronger C IV emission lines for color-selected quasars, than for grism-selected objects.

  20. FREE-FREE EMISSION AND RADIO RECOMBINATION LINES FROM PHOTOEVAPORATING DISKS

    SciTech Connect

    Pascucci, I.; Gorti, U.; Hollenbach, D.

    2012-06-01

    Recent infrared observations have demonstrated that photoevaporation driven by high-energy photons from the central star contributes to the dispersal of protoplanetary disks. Here, we show that photoevaporative winds should produce a detectable free-free continuum emission given the range of stellar ionizing photons and X-ray luminosities inferred for young Sun-like stars. We point out that Very Large Array observations of the nearby disk around TW Hya might have already detected this emission at centimeter wavelengths and calculate the wind electron density and mass flow rate. We also estimate the intensities of H radio recombination lines tracing the wind and discuss which ones could be detected with current instrumentation. The detection and profiles of these recombination lines would unambiguously prove our inference of free-free emission from photoevaporating disks like TW Hya. In addition, radio/millimeter data can help constraining wind parameters such as temperature and electron density that are fundamental in measuring mass flow rates.

  1. Ground-based observation of emission lines from the corona of a red-dwarf star.

    PubMed

    Schmitt, J H; Wichmann, R

    2001-08-02

    All 'solar-like' stars are surrounded by coronae, which contain magnetically confined plasma at temperatures above 106 K. (Until now, only the Sun's corona could be observed in the optical-as a shimmering envelope during a total solar eclipse.) As the underlying stellar 'surfaces'-the photospheres-are much cooler, some non-radiative process must be responsible for heating the coronae. The heating mechanism is generally thought to be magnetic in origin, but is not yet understood even for the case of the Sun. Ultraviolet emission lines first led to the discovery of the enormous temperature of the Sun's corona, but thermal emission from the coronae of other stars has hitherto been detectable only from space, at X-ray wavelengths. Here we report the detection of emission from highly ionized iron (Fe XIII at 3,388.1 A) in the corona of the red-dwarf star CN Leonis, using a ground-based telescope. The X-ray flux inferred from our data is consistent with previously measured X-ray fluxes, and the non-thermal line width of 18.4 km s-1 indicates great similarities between solar and stellar coronal heating mechanisms. The accessibility and spectral resolution (45,000) of the ground-based instrument are much better than those of X-ray satellites, so a new window to the study of stellar coronae has been opened.

  2. SDSS-IV eBOSS emission-line galaxy pilot survey

    NASA Astrophysics Data System (ADS)

    Comparat, J.; Delubac, T.; Jouvel, S.; Raichoor, A.; Kneib, J.-P.; Yèche, C.; Abdalla, F. B.; Le Cras, C.; Maraston, C.; Wilkinson, D. M.; Zhu, G.; Jullo, E.; Prada, F.; Schlegel, D.; Xu, Z.; Zou, H.; Bautista, J.; Bizyaev, D.; Bolton, A.; Brownstein, J. R.; Dawson, K. S.; Escoffier, S.; Gaulme, P.; Kinemuchi, K.; Malanushenko, E.; Malanushenko, V.; Mariappan, V.; Newman, J. A.; Oravetz, D.; Pan, K.; Percival, W. J.; Prakash, A.; Schneider, D. P.; Simmons, A.; Abbott, T. M. C.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Doel, P.; Eifler, T. F.; Estrada, J.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Miquel, R.; Plazas, A. A.; Reil, K.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Zhang, Y.

    2016-08-01

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195 000 emission-line galaxies (ELGs) to measure the baryonic acoustic oscillation (BAO) standard ruler at redshift 0.9. To test different ELG selection algorithms, 9000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Finally, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements. The catalog is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A121

  3. Survey of emission-line galaxies: Universidad Complutense de Madrid list

    NASA Technical Reports Server (NTRS)

    Zamorano, J.; Rego, Gallego, J.; Gallego, J. G.; Vitores, A. G.RA, R.; Gonzalez-Riestra, R..; Rodriguez-Caderot, G.

    1994-01-01

    A low-dispersion objective-prism survey for low-redshift emission-line galaxies (ELGs) is being carried out by the University Complutense de Madrid with the Schmidt telescope at the German-Spanish Observatory of Calar Alto (Almeria, Spain). A 4 deg full aperture prism, which provides a dispersion of 1950 A/mm, and IIIaF emulsion combination has been used to search for ELGs selected by the presence of H-alpha emission in their spectra. Our survey has proved to be able to recover objects already found by similar surveys with different techniques and, what is more important, to discover new objects not previously cataloged. A compilation of descriptions and positions, along with finding charts when necessary, is presented for 160 extragalactic emission-line objects. This is the first list, which contains objects located in a region of the sky covering 270 sq deg in 10 fields near alpha = 0(sup h) and delta = 20 deg.

  4. THE SINS SURVEY: BROAD EMISSION LINES IN HIGH-REDSHIFT STAR-FORMING GALAXIES

    SciTech Connect

    Shapiro, Kristen L.; Quataert, Eliot; Genzel, Reinhard; Foerster Schreiber, Natascha M.; Davies, Richard; Tacconi, Linda; Bouche, Nicolas; Buschkamp, Peter; Cresci, Giovanni; Eisenhauer, Frank; Genel, Shy; Hicks, Erin K. S.; Lutz, Dieter; Armus, Lee; Cimatti, Andrea; Daddi, Emanuele; Erb, Dawn K.; Lilly, Simon J.; Renzini, Alvio; Shapley, Alice

    2009-08-20

    High signal-to-noise, representative spectra of star-forming galaxies at z {approx} 2, obtained via stacking, reveal a high-velocity component underneath the narrow H{alpha} and [N II] emission lines. When modeled as a single Gaussian, this broad component has FWHM {approx}> 1500 km s{sup -1}; when modeled as broad wings on the H{alpha} and [N II] features, it has FWHM {approx}> 500 km s{sup -1}. This feature is preferentially found in the more massive and more rapidly star-forming systems, which also tend to be older and larger galaxies. We interpret this emission as evidence of either powerful starburst-driven galactic winds or active supermassive black holes (SMBHs). If galactic winds are responsible for the broad emission, the observed luminosity and velocity of this gas imply mass outflow rates comparable to the star formation rate. On the other hand, if the broad-line regions of active black holes account for the broad feature, the corresponding black holes masses are estimated to be an order of magnitude lower than those predicted by local scaling relations, suggesting a delayed assembly of SMBHs with respect to their host bulges.

  5. A Study Of CH A-X And B-X Emission Lines In Comets

    NASA Astrophysics Data System (ADS)

    Sohn, Mi-Rim; Kim, S.

    2012-10-01

    We analyzed CH A-X (0-0) and B-X (0-0) emission lines shown in high-resolution (R 20,000) spectra of five different comets: Austin (C/1989 X1)[1], 122P/de Vico[2], Hyakutake (C/1996 B2)[3], Machholz (C/2004 Q2) and 103P/Hartley with a time-dependent fluorescence model. We compare the characteristics of the emission intensities of the short-lived CH radicals among the comets. We derived the rotational temperatures from CH band structure for each comet. We will present difference and similarity of the CH emission lines considering the short lifetimes of the CH radicals. References [1] M. E. Brown and H. Spinrad, bull. Amer. Astron. Soc., 22, 2200 (1990). [2] A. L. Cochran and W. D. Cochran, Icarus, 157, 297-308 (2002). [3] R. Meier, D. Wellnitz, S. J. Kim and M. F. A’Hearn, Icarus, 136, 268-279 (1998).

  6. SOLAR FLARE CHROMOSPHERIC LINE EMISSION: COMPARISON BETWEEN IBIS HIGH-RESOLUTION OBSERVATIONS AND RADIATIVE HYDRODYNAMIC SIMULATIONS

    SciTech Connect

    Costa, Fatima Rubio da; Petrosian, Vahé; Kleint, Lucia; Dalda, Alberto Sainz; Liu, Wei

    2015-05-01

    Solar flares involve impulsive energy release, which results in enhanced radiation over a broad spectral range and a wide range of heights. In particular, line emission from the chromosphere can provide critical diagnostics of plasma heating processes. Thus, a direct comparison between high-resolution spectroscopic observations and advanced numerical modeling results could be extremely valuable, but has not yet been attempted. In this paper, we present such a self-consistent investigation of an M3.0 flare observed by the Dunn Solar Telescope’s Interferometric Bi-dimensional Spectrometer (IBIS) on 2011 September 24 which we have modeled using the radiative hydrodynamic code RADYN. We obtained images and spectra of the flaring region with IBIS in Hα 6563 Å and Ca ii 8542 Å, and with RHESSI in X-rays. The latter observations were used to infer the non-thermal electron population, which was passed to RADYN to simulate the atmospheric response to electron collisional heating. We then synthesized spectral lines and compared their shapes and intensities to those observed by IBIS and found a general agreement. In particular, the synthetic Ca ii 8542 Å profile fits well to the observed profile, while the synthetic Hα profile is fainter in the core than for the observation. This indicates that Hα emission is more responsive to the non-thermal electron flux than the Ca ii 8542 Å emission. We suggest that it is necessary to refine the energy input and other processes to resolve this discrepancy.

  7. 2D photochemical model for forbidden oxygen line emission for comet 1P/Halley

    NASA Astrophysics Data System (ADS)

    Cessateur, G.; De Keyser, J.; Maggiolo, R.; Rubin, M.; Gronoff, G.; Gibbons, A.; Jehin, E.; Dhooghe, F.; Gunell, H.; Vaeck, N.; Loreau, J.

    2016-11-01

    We present here a 2D model of photochemistry for computing the production and loss mechanisms of the O(1S) and O(1D) states, which are responsible for the emission lines at 577.7, 630, and 636.4 nm, in case of the comet 1P/Halley. The presence of O2 within cometary atmospheres, measured by the in situ Rosetta and Giotto missions, necessitates a revision of the usual photochemical models. Indeed, the photodissociation of molecular oxygen also leads to a significant production of oxygen in excited electronic states. In order to correctly model the solar ultraviolet (UV) flux absorption, we consider here a 2D configuration. While the green to red-doublet ratio is not affected by the solar UV flux absorption, estimates of the red-doublet and green lines emissions are, however, overestimated by a factor of 2 in the 1D model compared to the 2D model. Considering a spherical symmetry, emission maps can be deduced from the 2D model in order to be directly compared to ground and/or in situ observations.

  8. EVN maps of 5 cm line OH emission from star-forming regions

    NASA Astrophysics Data System (ADS)

    Desmurs, J.-F.; Baudry, A.; Graham, D. A.

    We have used three antennas of the EVN (Effelsberg, Medicina and Jodrell Bank) to observe in W3(OH) and in five other star-forming regions, simultaneously, and for the first time, the two main lines of the 2φ 3/2, J= 5/2 excited state of OH with right and left circularly polarized feeds. The data were correlated with the MkIII MPIfR correlator in Bonn and processed with the AIPS package at the Observatoire de Bordeaux. In W3(OH) we made cleaned maps of all individual channels for each line and polarization. These maps made with a 5×6.5 mas beam reveal complex kinematics and spatial structure with both extended emission and unresolved features. This fact and polarization properties demon-strate the masing nature of the emission. Maser features are identified by searching for emission over adjacent channels, and adjacent positions (within about one synthesized beam) in both polarizations after we had mapped and selected one channel as a phase reference. We have been able to identify OH Zeeman pairs and to estimate the magnetic field strength across W3(OH); the field varies from about 1 to 10 mG. At the time of this conference, three other star-forming regions (M17, ON1 and W51) show fringes while two other regions are still incompletely processed.

  9. A New Spectropolarimeter to Study the Polarization of Earth's Auroral Emission Lines

    NASA Astrophysics Data System (ADS)

    Lamy, H.; Barthelemy, M.; Lilensten, J.; Johnsen, M. G.

    2015-12-01

    In the last few years, a lot of efforts were made in order to measure and model the polarization of the auroral red line emission (λ 630nm). This polarization arises due to impact of thermospheric oxygen atoms with precipitating electrons collimated along the geomagnetic field but is diluted by many competing production mechanisms that do not produce polarization, and other loss mechanisms as well. Observations show that the red line emission is polarized at a level of a few percent. In order to continue investigating this field, we are building a spectropolarimeter able to measure the polarization of the full auroral spectrum between 400 and 700 nm. In particular the blue emission band due to N2+ 1NG (λ 428nm) is a very interesting candidate for polarization as it is produced by impact with precipitating electrons only. A test campaign with a first version of the spectropolarimeter was carried out in Skibotn, Norway, in December 2014 aiming at validating the experimental concept and estimating the integration times needed to obtain adequate S/N ratios. In the coming months, we will work on improving the design and make some twilight sky observations in Brussels as a calibration test. This presentation will review the principle of the instrument, the observations carried out in Skibotn as well as the recent work and tests made on the instrument.

  10. SDSS-IV eBOSS emission-line galaxy pilot survey

    SciTech Connect

    Comparat, J.; Delubac, T.; Jouvel, S.; Raichoor, A.; Kneib, J-P.; Yèche, C.; Abdalla, F. B.; Le Cras, C.; Maraston, C.; Wilkinson, D. M.; Zhu, G.; Jullo, E.; Prada, F.; Schlegel, D.; Xu, Z.; Zou, H.; Bautista, J.; Bizyaev, D.; Bolton, A.; Brownstein, J. R.; Dawson, K. S.; Escoffier, S.; Gaulme, P.; Kinemuchi, K.; Malanushenko, E.; Malanushenko, V.; Mariappan, V.; Newman, J. A.; Oravetz, D.; Pan, K.; Percival, W. J.; Prakash, A.; Schneider, D. P.; Simmons, A.; Abbott, T. M. C.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Doel, P.; Eifler, T. F.; Estrada, J.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; Marshall, J. L.; Miquel, R.; Plazas, A. A.; Reil, K.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Walker, A. R.; Zhang, Y.

    2016-08-09

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195,000 emission-line galaxies (ELGs) to measure the Baryonic Acoustic Oscillation standard ruler (BAO) at redshift 0.9. To test different ELG selection algorithms, 9,000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Lastly, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements.

  11. SDSS-IV eBOSS emission-line galaxy pilot survey

    DOE PAGES

    Comparat, J.; Delubac, T.; Jouvel, S.; ...

    2016-08-09

    The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195,000 emission-line galaxies (ELGs) to measure the Baryonic Acoustic Oscillation standard ruler (BAO) at redshift 0.9. To test different ELG selection algorithms, 9,000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error.more » Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Lastly, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements.« less

  12. On the Origin of the Flare Emission in IRIS’ SJI 2832 Filter:Balmer Continuum or Spectral Lines?

    NASA Astrophysics Data System (ADS)

    Kleint, Lucia; Heinzel, Petr; Krucker, Säm

    2017-03-01

    Continuum (“white-light,” WL) emission dominates the energetics of flares. Filter-based observations, such as the IRIS SJI 2832 filter, show WL-like brightenings during flares, but it is unclear whether the emission arises from real continuum emission or enhanced spectral lines, possibly turning into emission. The difficulty in filter-based observations, contrary to spectral observations, is to determine which processes contribute to the observed brightening during flares. Here we determine the contribution of the Balmer continuum and the spectral line emission to IRIS’ SJI 2832 emission by analyzing the appropriate passband in simultaneous IRIS NUV spectra. We find that spectral line emission can contribute up to 100% to the observed slitjaw images (SJI) emission, that the relative contributions usually temporally vary, and that the highest SJI enhancements that are observed are most likely because of the Balmer continuum. We conclude that care should be taken when calling SJI 2832 a continuum filter during flares, because the influence of the lines on the emission can be significant.

  13. Excitation Mechanisms of Near-Infrared Emission Lines in LINER Galaxies

    NASA Astrophysics Data System (ADS)

    Boehle, Anna

    2017-01-01

    I will present high spatial resolution, integral field spectroscopic observations of the nearby LINER (low ionization nuclear emission line region) galaxy NGC 404. LINERs are found at the centers of ~1/3 of galaxies within 40 Mpc, but their physical nature is not well understood. Although NGC 404 is thought to host a intermediate mass black hole at its center, it is unclear whether accretion onto the black hole or another mechanism such as shock excitation drives its LINER emission. We use the OSIRIS near-infrared integral field spectrograph at Keck Observatory behind laser guide star adaptive optics to map the strength and kinematics of [FeII], H2, and hydrogen recombination lines in the nucleus of NGC 404. These observations have a spatial pixel sampling of 0.5 pc and span the central 30 pc of the galaxy. We find that the ionized and molecular gas show differences in their morphology and kinematics on parsec scales. In particular, there are regions with line ratios of [FeII]/Pa-β that are much higher than previously seen in spatially integrated spectra, significantly restricting the possible excitation mechanisms of the near-infrared emission lines in this source. We are also applying these analysis techniques to 10 additional nearby LINERs, a part of a larger sample of 14 sources, to understand what drives the emission lines in these active galaxies. As a part of this program, I worked on the upgrade of the detector in the OSIRIS spectrograph, which has allowed observations for this survey obtained since January 2016 to be taken with increased instrument sensitivity of a factor of ~2 at J-band wavelengths (1.2 - 1.4 microns) and ~1.6 at H- and K-band wavelengths (1.5 - 2.4 microns). I will present results from the LINER survey, the OSIRIS detector upgrade, and also touch on related work using stellar orbits around the Milky Way supermassive black hole Sgr A* to constrain the mass and distance to our own Galactic Center.

  14. Far-infrared emission line spectroscopy of planetary nebulae from the KAO

    NASA Technical Reports Server (NTRS)

    Dinerstein, Harriet L.

    1994-01-01

    The main focus of the overall project was to study the properties of planetary nebulae using far-infrared emission lines. The observations were conducted with the 'cooled grating spectrometer' or CGS, a moderate-resolution echelle spectrometer designed and built at the Ames Research Center. During the first few years of the program, the emphasis was on emission lines of doubly-ionized oxygen and nitrogen ((O III) 52 and 88 microns, (N III) 57 microns), which arise in the ionized regions of the nebulae. Starting around 1989, our emphasis shifted to observing fine-structure lines of neutral oxygen and singly-ionized carbon ((O I) 63 and 145 microns, (C II) 157 microns), which arise from predominantly neutral material outside the ionized regions. This program was typically assigned one or two observing flights per year. Because these studies required obtaining a substantial sample of objects in order to reach meaningful conclusions, publication of comprehensive papers summarizing all of the results is still pending. However, numerous interim reports based on the airborne results as well as on closely-related supporting observations have been published during the grant period. The bibliographic information for these reports is given in the publications section. An overall summary of the planetary nebula results was presented at the Airborne Astronomy Symposium (20th Anniversary of the KAO) on 8 July 1994; reprints will be provided when available. In parallel with the planetary nebula study, we also observed the (O III) and (N III) lines in several H II regions, and attempted (unsuccessfully) to detect these lines in several old nova remnants and the supernova remnant Cassiopeia A.

  15. Spatially Resolved HST Grism Spectroscopy of a Lensed Emission Line Galaxy at z ~ 1

    NASA Astrophysics Data System (ADS)

    Frye, Brenda L.; Hurley, Mairead; Bowen, David V.; Meurer, Gerhardt; Sharon, Keren; Straughn, Amber; Coe, Dan; Broadhurst, Tom; Guhathakurta, Puragra

    2012-07-01

    We take advantage of gravitational lensing amplification by A1689 (z = 0.187) to undertake the first space-based census of emission line galaxies (ELGs) in the field of a massive lensing cluster. Forty-three ELGs are identified to a flux of i 775 = 27.3 via slitless grism spectroscopy. One ELG (at z = 0.7895) is very bright owing to lensing magnification by a factor of ≈4.5. Several Balmer emission lines (ELs) detected from ground-based follow-up spectroscopy signal the onset of a major starburst for this low-mass galaxy (M * ≈ 2 × 109 M ⊙) with a high specific star formation rate (≈20 Gyr-1). From the blue ELs we measure a gas-phase oxygen abundance consistent with solar (12+log(O/H) = 8.8 ± 0.2). We break the continuous line-emitting region of this giant arc into seven ~1 kpc bins (intrinsic size) and measure a variety of metallicity-dependent line ratios. A weak trend of increasing metal fraction is seen toward the dynamical center of the galaxy. Interestingly, the metal line ratios in a region offset from the center by ~1 kpc have a placement on the blue H II region excitation diagram with f ([O III])/f (Hβ) and f ([Ne III])/f (Hβ) that can be fitted by an active galactic nucleus (AGN). This asymmetrical AGN-like behavior is interpreted as a product of shocks in the direction of the galaxy's extended tail, possibly instigated by a recent galaxy interaction. Based, in part, on data obtained with 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.

  16. LSDCat: Detection and cataloguing of emission-line sources in integral-field spectroscopy datacubes

    NASA Astrophysics Data System (ADS)

    Herenz, Edmund Christian; Wisotzki, Lutz

    2017-06-01

    We present a robust, efficient, and user-friendly algorithm for detecting faint emission-line sources in large integral-field spectroscopic datacubes together with the public release of the software package Line Source Detection and Cataloguing (LSDCat). LSDCat uses a three-dimensional matched filter approach, combined with thresholding in signal-to-noise, to build a catalogue of individual line detections. In a second pass, the detected lines are grouped into distinct objects, and positions, spatial extents, and fluxes of the detected lines are determined. LSDCat requires only a small number of input parameters, and we provide guidelines for choosing appropriate values. The software is coded in Python and capable of processing very large datacubes in a short time. We verify the implementation with a source insertion and recovery experiment utilising a real datacube taken with the MUSE instrument at the ESO Very Large Telescope. The LSDCat software is available for download at http://muse-vlt.eu/science/tools and via the Astrophysics Source Code Library at http://ascl.net/1612.002

  17. The Importance of Broad Emission Line Widths in Single-epoch Black Hole Mass Estimates

    NASA Astrophysics Data System (ADS)

    Assef, R. J.; Frank, S.; Grier, C. J.; Kochanek, C. S.; Denney, K. D.; Peterson, B. M.

    2012-07-01

    Estimates of the mass of super-massive black holes (BHs) in distant active galactic nuclei (AGNs) can be obtained efficiently only through single-epoch (SE) spectra, using a combination of their broad emission line widths and continuum luminosities. Yet the reliability and accuracy of the method and the resulting mass estimates, M BH, remain uncertain. A recent study by Croom using a sample of Sloan Digital Sky Survey, 2dF QSO Redshift Survey, and 2dF-SDSS LRG and QSO Survey quasars suggests that line widths contribute little information about the BH mass in these SE estimates and can be replaced by a constant value without significant loss of accuracy. In this Letter, we use a sample of nearby reverberation-mapped AGNs to show that this conclusion is not universally applicable. We use the bulge luminosity (L Bulge) of these local objects to test how well the known M BH-L Bulge correlation is recovered when using randomly assigned line widths instead of the measured ones to estimate M BH. We find that line widths provide significant information about M BH, and that for this sample, the line width information is just as significant as that provided by the continuum luminosities. We discuss the effects of observational biases upon the analysis of Croom and suggest that the results can probably be explained as a bias of flux-limited, shallow quasar samples.

  18. SPITZER SPECTRAL LINE MAPPING OF PROTOSTELLAR OUTFLOWS. II. H{sub 2} EMISSION IN L1157

    SciTech Connect

    Nisini, Brunella; Giannini, Teresa; Antoniucci, Simone; Neufeld, David A.; Yuan Yuan; Bergin, Edwin A.; Melnick, Gary J.

    2010-11-20

    We present an analysis of Spitzer-IRS spectroscopic maps of the L1157 protostellar outflow in the H{sub 2} pure-rotational lines from S(0) to S(7). The aim of this work is to derive the physical conditions pertaining to the warm molecular gas and study their variations within the flow. The mid-IR H{sub 2} emission follows the morphology of the precessing flow, with peaks correlated with individual CO clumps and H{sub 2} 2.12 {mu}m ro-vibrational emission. More diffuse emission delineating the CO cavities is detected only in the low-laying transitions, with J{sub lower{<=}} 2. The H{sub 2} line images have been used to construct two-dimensional maps of N(H{sub 2}), H{sub 2} ortho-to-para ratio (OPR), and temperature spectral index {beta}, in the assumption of a gas temperature stratification where the H{sub 2} column density varies as T {sup -}{beta}. Variations of these parameters are observed along the flow. In particular, the OPR ranges from {approx}0.6 to 2.8, highlighting the presence of regions subject to recent shocks where the OPR has not had time yet to reach the equilibrium value. Near-IR spectroscopic data on ro-vibrational H{sub 2} emission have been combined with the mid-IR data and used to derive additional shock parameters in the brightest blueshifted and redshifted emission knots. A high abundance of atomic hydrogen (H/H{sub 2} {approx} 0.1-0.3) is implied by the observed H{sub 2} column densities, assuming n(H{sub 2}) values as derived by independent SiO observations. The presence of a high fraction of atomic hydrogen indicates that a partially dissociative shock component should be considered for the H{sub 2} excitation in these localized regions. However, planar shock models, either of C- or J-type, are not able to consistently reproduce all the physical parameters derived from our analysis of the H{sub 2} emission. Globally, H{sub 2} emission contributes to about 50% of the total shock radiated energy in the L1157 outflow. We find that the

  19. Peculiar Emission Line Generation from Ultra-Rapid Quasi-Periodic Oscillations of Exotic Astronomical Objects

    NASA Astrophysics Data System (ADS)

    Borra, E. F.

    2017-06-01

    The purpose of this article is to alert astronomers, particularly those using spectroscopic surveys, to the fact that exotic astronomical objects (e.g. quasars or active galactic nuclei) that send ultra-rapid quasi periodic pulses of optical light would generate spectroscopic features that look like emission lines. This gives a simple technique to find quasi periodic pulses separated by times smaller than a nanosecond. One should look for emission lines that cannot be identified with known spectral lines in spectra. Such signals, generated by slower pulses, could also be found in the far infra-red, millimeter and radio regions, where they could be detected as objects unusually bright in a single narrow-band filter or channel. The outstanding interest of the technique comes from its simplicity so that it can be used to find ultra-rapid quasi-periodic oscillators in large astronomical surveys. A very small fraction of objects presently identified as Lyman α emitters that do not have other spectral features to confirm the Lyman α redshift, may possibly be quasi-periodic oscillators. However this is only a hypothesis that needs more observations for confirmation.

  20. Analysis of optimum diameter of orbit of transmission line source in positron emission tomograph

    SciTech Connect

    Yamamoto, S.; Amano, M.; Hirose, Y.; Muira, S.; Kanno, I.

    1989-02-01

    Accurate attenuation correction is one of the most important factors to achieve quantitative measurements in positron emission tomography (PET). A transmission scan is most commonly used technique for the attenuation correction in PET. A difficulty in transmission scan is relatively long period to obtain a data with good signal-