Model Line Profiles Research Articles

Line formation in the inner winds of classical T Tauri stars: testing the conical-shell wind solution

We present the emission line profile models of hydrogen and helium based on the results from axisymmetric magnetohydrodynamics (MHD) simulations of the wind formed near the disk-magnetosphere boundary of classical T Tauri stars (CTTSs). We extend the previous outflow models of `the conical-shell wind' by Romanova et al. to include a well defined magnetospheric accretion funnel flow which is essential for modelling the optical and near-infrared hydrogen and helium lines of CTTSs. The MHD model with an intermediate mass-accretion rate shows outflows in conical-shell shape with a half opening angle about 35 degrees. The flow properties such as the maximum outflow speed in the conical-shell wind, maximum inflow speed in the accretion funnel, mass-accretion and mass-loss rates are comparable to those found in a typical CTTS. The density, velocity and modified temperature from the MHD simulations are used in a separate radiative transfer model to predict the line profiles and test the consistency of the MHD models with observations. The line profiles are computed with various combinations of X-ray luminosities, temperatures of X-ray emitting plasma, and inclination angles. A rich diversity of line profile morphology is found, and many of the model profiles are very similar to those found in observations. We find that the conical-shell wind may contribute to the emission in some hydrogen lines (e.g. H-alpha, H-beta, Pa-beta and Pa-gamma) significantly when the temperature in the wind is relatively high (e.g. \sim 10^{4} K); however, the wind contribution decreases rapidly when a lower wind temperature is adopted. The model well reproduces a relatively narrow and low-velocity blueshifted absorption component in He I (10830), which are often seen in observations.

Experimental and theoretical study of N2-broadened acetylene line parameters in the ν1 + ν3 band over a range of temperatures

N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the ν1 + ν3 band of acetylene at seven temperatures in the range 213–333 K to obtain the temperature dependences of broadening and shift coefficients. For the room-temperature spectra the line mixing effects have been also investigated. The Voigt and hard-collision line profile models were used to retrieve the line parameters. All spectra were recorded using a 3-channel tuneable diode laser spectrometer. The line-broadening and line-shifting coefficients as well as their temperature-dependence parameters have been also evaluated theoretically, in the frame of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole–quadrupole and pairwise atom–atom interactions as well as on exact trajectories driven by an effective isotropic potential.

Collisional parameters of N2 broadened methane lines in the R9 multiplet of the 2ν3 band. Multispectrum fittings of the overlapping spectral lines

A high-sensitive two-channel photo-acoustic (PA) spectrometer with a near infrared diode laser was used to make precise measurements of N2-broadened methane spectra in the R9 multiplet of 2ν3 band. For the accurate retrieval of spectroscopic line parameters (intensities, positions at zero pressure, pressure-shifting and -broadening, collisional narrowing and line mixing coefficients) from the methane PA spectra, a program based on a multispectrum fitting procedure has been used. The multispectrum least squares fitting procedure is based on a relatively simple line profile model and on the linear pressure dependences of the line profile parameters. The line parameters were determined for 11 lines of the methane 2ν3 R9 multiplet. The results have been compared with other available data.

Under-Developed and Under-Utilized Eclipsing Binary Model Capabilities

Existing but largely unused binary star model capabilities are examined. An easily implemented scheme is parameterization of starspot growth and decay that can stimulate work on outer convection zones and their dynamos. Improved precision in spot computation now enhances analysis of very precise data. An existing computational model for blended spectral line profiles is accurate for binary system effects but needs to include damping, thermal Doppler, and other intrinsic broadening effects. Binary star ephemerides had been found exclusively from eclipse timings until recently, but now come also from whole light and radial velocity curves. A logical further development will be to expand these whole curve solutions to include eclipse timings. An attenuation model for circumstellar clouds, with several absorption and scattering mechanisms, has been applied only once, perhaps because the model clouds have fixed locations. However the clouds could be made to move dynamically and be combined into moving streams and disks. An area of potential interest is polarization curve analysis, where incentive for modeling could follow from publication of observed polarization curves. Other recent advances include direct single step solutions for temperatures of both stars of an eclipsing binary and third body kinematics from combined light and velocity curves.

A pure H2O isolated line-shape model based on classical molecular dynamics simulations of velocity changes and semi-classical calculations of speed-dependent collisional parameters

It is well known that the Voigt profile does not well describe the (measured) shapes of isolated lines. This is due to the neglect of the intermolecular collision-induced velocity changes and of the speed dependence of the collisional parameters. In this paper, we present a new line profile model for pure H(2)O which takes both of these effects into account. The speed dependence of the collisional parameters has been calculated by a semi-classical method. The velocity changes have been modeled by using the Keilson-Storer collision kernel with two characteristic parameters. The latter have been deduced from classical molecular dynamics simulations which also indicate that, for pure H(2)O, the correlation between velocity-changing and state-changing collisions is not negligible, a result confirmed by the analysis of measured spectra. A partially correlated speed-dependent Keilson-Storer model has thus been adopted to describe the line-shape. Comparisons between simulated spectra and measurements for four self-broadened lines in the near-infrared at various pressures show excellent agreements.

Application of a Bayesian Method to Absorption Spectral-Line Finding in Simulated ASKAP Data

AbstractThe large spectral bandwidth and wide field of view of the Australian SKA Pathfinder radio telescope will open up a completely new parameter space for large extragalactic HI surveys. Here we focus on identifying and parametrising HI absorption lines which occur in the line of sight towards strong radio continuum sources. We have developed a method for simultaneously finding and fitting HI absorption lines in radio data by using multi-nested sampling, a Bayesian Monte Carlo algorithm. The method is tested on a simulated ASKAP data cube, and is shown to be reliable at detecting absorption lines in low signal-to-noise data without the need to smooth or alter the data. Estimation of the local Bayesian evidence statistic provides a quantitative criterion for assigning significance to a detection and selecting between competing analytical line-profile models.

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

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.

Collision parameters of N2-broadened methane lines in R5 multiplet of 2ν 3 band. Multispectrum fitting of overlapping spectral lines

The results of the investigation of absorption spectra of the methane R5 multiplet of 2ν 3 band, broadened by nitrogen, are presented. The absorption spectra of the methane-nitrogen mixture (CH4:N2 = 1:113.36) were recorded, using a two-channel photometric spectrometer, based on a tunable diode laser. The multispectrum least-squares fitting procedure was applied to all experimental spectra, recorded at different pressures, using the program, developed at IAO SB RAS (Protasevich, 2011). The program is based on a relatively simple line-profile model proposed in Pine (J. Quant. Spectrosc. Radiat. Transf. 57:145, 1997) and linear pressure dependence of the line-profile parameters. The line center positions, intensities, broadening, shifting, and mixing coefficients were determined for four lines of the methane R5 multiplet. The results have been compared with other available data.

The 1.10- and 1.18-μm nightside windows of Venus observed by SPICAV-IR aboard Venus Express

Observations of the 1.10- and 1.18-μm nightside windows by the SPICAV-IR instrument aboard Venus Express were analyzed to characterize the various sources of gaseous opacity and determine the H 2O mole fraction in the lower atmosphere of Venus. We showed that the line profile model of Afanasenko and Rodin (Afanasenko, T.S., Rodin, A.V. [2007]. Astron. Lett. 33, 203–210) underestimates the CO 2 absorption in the high-wavelength wing of the 1.18-μm window and we derived an empirical lineshape that matches this wing well. An additional continuum opacity is required to reproduce the variation of the 1.10- and 1.18-μm radiances with surface elevation as observed by the VIRTIS-M instrument aboard Venus Express. A constant absorption coefficient of 0.7 ± 0.2 × 10 −9 cm −1 am −2 best reproduces the observed variation. We compared spectra calculated with different CO 2 and H 2O line lists. We found that the CDSD line list lacks the 5 ν 1 + ν 3 series of CO 2 bands, which provide significant opacity in Venus’ deep atmosphere, and we have constructed a composite line list that best reproduces the observations. We also showed for the first time that HDO brings significant absorption at 1140–1190 nm. Using the best representation of the atmospheric opacity we could reach, we retrieved a water vapor mole fraction of 30 - 5 + 10 ppmv, pertaining to the altitude range 5–25 km. Combined with previous measurements in the 1.74- and 2.3-μm windows, this result provides strong evidence for a uniform H 2O profile below 40 km, in agreement with chemical models.

Multidimensional models of hydrogen and helium emission line profiles for classical T Tauri stars: method, tests and examples

We present multidimensional non-LTE radiative transfer models of hydrogen and helium line profiles formed in the accretion flows and the outflows near the star-disk interaction regions of classical T Tauri stars (CTTSs). The statistical equilibrium calculations, performed under the assumption of the Sobolev approximation using the radiative transfer code TORUS, has been improved to include He I and He II energy levels. This allows us to probe the physical conditions of the inner wind of CTTSs by simultaneously modelling the robust wind diagnostic line He I (10830) and the accretion diagnostic lines such as Pa-beta, Br-gamma and He I (5876). The code has been tested in 1 and 2-D problems, and we have shown that the results are in agreement with established codes. We apply the model to the complex flow geometries of CTTSs. Example model profiles are computed using the combinations of (1) magnetospheric accretion and disc wind, and (2) magnetospheric accretion and the stellar wind. In both cases, the model produces line profiles which are qualitatively similar to those found in observations. Our models are consistent with the scenario in which the narrow blueshifted absorption component of He I (10830) seen in observations is caused by a disc wind, and the wider blueshifted absorption component (the P-Cygni profile) is caused by a bipolar stellar wind. However, we do not have a strong constraint on the relative importance of the wind and the magnetosphere for the `emission' component. Our preliminary calculations suggest that the temperatures of the disc wind, stellar wind and the magnetosphere cannot be much higher than ~10,000 K, on the basis of the strengths of hydrogen lines. With these low temperatures, we find that the photoionzation by high energy photons (e.g. X-rays) is necessary to produce He I (10830) in emission and to produce the blueshifted absorption components.

THE HANLE EFFECT AS A DIAGNOSTIC OF MAGNETIC FIELDS IN STELLAR ENVELOPES. V. THIN LINES FROM KEPLERIAN DISKS

This paper focuses on the polarized profiles of resonance scattering lines that form in magnetized disks. Optically thin lines from Keplerian planar disks are considered. Model line profiles are calculated for simple field topologies of axial fields (i.e., vertical to the disk plane) and toroidal fields (i.e., purely azimuthal). A scheme for discerning field strengths and geometries in disks is developed based on Stokes Q-U diagrams for the run of polarization across line profiles that are Doppler broadened by the disk rotation. A discussion of the Hanle effect for magnetized disks in which the magnetorotational instability (MRI) is operating is also presented. Given that the MRI has a tendency to mix the vector field orientation, it may be difficult to detect the disk fields with the longitudinal Zeeman effect, since the amplitude of the circularly polarized signal scales with the net magnetic flux in the direction of the observer. The Hanle effect does not suffer from this impediment, and so a multi-line analysis could be used to constrain field strengths in disks dominated by the MRI.

Line formation in AGB atmospheres including velocity effects

<i>Context. <i/>Towards the end of the evolutionary stage of the asymptotic giant branch (AGB) the atmospheres of evolved red giants are considerably influenced by radial pulsations of the stellar interiors and developing stellar winds. The resulting complex velocity fields severely affect molecular line profiles (shapes, time-dependent shifts in wavelength, multiple components) observable in near-infrared spectra of long period variables. Time-series high-resolution spectroscopy allows us to probe the atmospheric kinematics and thereby study the mass loss process.<i>Aims. <i/>With the help of model calculations the complex line formation process in AGB atmospheres was explored with the focus on velocity effects. Furthermore, we aimed for atmospheric models which are able to quantitatively reproduce line profile variations found in observed spectra of pulsating late-type giants.<i>Methods. <i/>Models describing pulsation-enhanced dust-driven winds were used to compute synthetic spectra under the assumptions of chemical equilibrium and LTE. For this purpose, we used molecular data from line lists for the considered species and solved the radiative transfer in spherical geometry including the effects of velocity fields. Radial velocities (RV) derived from Doppler-shifted (components of) synthetic line profiles provide information on the gas velocities in the line-forming region of the spectral features. In addition, we made use of radial optical depth distributions to give estimates for the layers where lines are formed and to illustrate the effects of velocities in the line formation process.<i>Results. <i/>Assuming uniform gas velocities for all depth points of an atmospheric model we estimated the conversion factor between gas velocities and measured RVs to <i>p<i/> = <i>u<i/><sub>gas<sub/>/RV <i>≈<i/> 1.2–1.5. On the basis of dynamic model atmospheres and by applying our spectral synthesis codes we investigated in detail the finding that various molecular features in AGB spectra originate at different geometrical depths of the very extended atmospheres of these stars. We show that the models are able to quantitatively reproduce the characteristic line profile variations of lines sampling the deep photosphere (CO <i>Δ<i/><i>v<i/> = 3, CN) of Mira variables and the corresponding discontinuous, S-shaped RV curve. The global velocity fields (traced by different features) of typical long-period variables are also realistically reproduced. Possible reasons for discrepancies concerning other modelling results (e.g. CO <i>Δ<i/><i>v<i/> = 2 lines) are outlined. In addition, we present a model showing variations of CO <i>Δ<i/><i>v<i/> = 3 line profiles comparable to observed spectra of semiregular variables and discuss that the non-occurence of line doubling in these objects may be due to a density effect.<i>Conclusions. <i/>The results of our line profile modelling are another indication that the dynamic models studied here are approaching a realistic representation of the outer layers of AGB stars with or without mass loss.

A mass-loss rate determination for ζ Puppis from the quantitative analysis of X-ray emission-line profiles

We fit every emission line in the high-resolution Chandra grating spectrum of zeta Pup with an empirical line profile model that accounts for the effects of Doppler broadening and attenuation by the bulk wind. For each of sixteen lines or line complexes that can be reliably measured, we determine a best-fitting fiducial optical depth, tau_* = kappa*Mdot/4{pi}R_{\ast}v_{\infty}, and place confidence limits on this parameter. These sixteen lines include seven that have not previously been reported on in the literature. The extended wavelength range of these lines allows us to infer, for the first time, a clear increase in tau_* with line wavelength, as expected from the wavelength increase of bound-free absorption opacity. The small overall values of tau_*, reflected in the rather modest asymmetry in the line profiles, can moreover all be fit simultaneously by simply assuming a moderate mass-loss rate of 3.5 \pm 0.3 \times 10^{-6} Msun/yr, without any need to invoke porosity effects in the wind. The quoted uncertainty is statistical, but the largest source of uncertainty in the derived mass-loss rate is due to the uncertainty in the elemental abundances of zeta Pup, which affects the continuum opacity of the wind, and which we estimate to be a factor of two. Even so, the mass-loss rate we find is significantly below the most recent smooth-wind H-alpha mass-loss rate determinations for zeta Pup, but is in line with newer determinations that account for small-scale wind clumping. If zeta Pup is representative of other massive stars, these results will have important implications for stellar and galactic evolution.

Time-resolved spectroscopy of the sdBV V338 Serpentis

We obtained 1955 high-resolution spectra of the high-amplitude pulsating subdwarf B star V338 Ser with the FIES spectrograph at the 2.5 m Nordic Optical Telescope covering 4 full nights in May–June 2009. Here we present the first results from phase-folding the data on the main pulsation mode, as revealed by simultaneous B-band photometry obtained with the Mercator 1.25 m and Baker 0.4 m telescopes. We compare the results with a sample line-profile model produced with LTE atmospheres and bruce+kylie.

Diode-laser spectroscopy: Pressure dependence of N 2-broadening coefficients of lines in the [formula omitted] band of C 2H 2

In this work, we have measured the N 2-broadening coefficients of 12 absorption lines in the ν 4 + ν 5 band of acetylene at room temperature, using a tunable diode-laser spectrometer. For each line under study, we have recorded spectra at 4–16 pressures of nitrogen ranging from 4.03 to 179.5 mbar. The line profiles were individually fitted, at each pressure, with different line shape models including fine effects as Dicke narrowing or/and speed dependence effect. From these fits, we have obtained the collisional half-widths at each pressure and then determined accurately the N 2-broadening coefficients of 12 lines. After that, we have studied the pressure dependence of the collisional broadening and narrowing coefficients following the considered line profile model. Finally, our results are compared with the previous studies realized in various absorption bands.

Dayglow on Mars: Kinetic modelling with SPICAM UV limb data

The UV spectrometer experiment SPICAM onboard ESA Mars Express has been orbiting Mars since December 2003. We present here some comparisons between airglow data that have been newly interpreted with the advanced kinetic model Trans-Mars. A series of numerical one-dimensional kinetic models, in the Trans-* family [Lilensten, J., Blelly. P.L., 2002. The TEC and F2 parameters as tracers of the ionosphere and thermosphere. J. Atmos. Solar-Terrestrial Phys. 64, 775–793] has been developed over the last years to take into account of airglow processes and yield altitude line profiles in planetary upper atmospheres (Earth, Venus, Titan and Mars). Trans-Mars is the last evolution of these simulations, applied to Mars. Electron and photon cross sections have been recently updated. The computed model line profiles are comparable to those of Fox and Dalgarno [1979b. Ionization, luminosity, and heating of the upper atmosphere of Mars. J. Geophys. Res. 84, 7315–7333] and Shematovich et al. [2008. Monte Carlo model of electron transport for the calculation of Mars dayglow emissions. J. Geophys. Res. (Planets) 113(E12), 2011]. Nearly 70000 limb UV spectra recorded by SPICAM between October 2004 and May 2006 are analysed in order to obtain altitude emission profiles on the main dayglow emissions. A variable point spread function (PSF) determined statistically throughout the wavelength range is used to estimate precisely the intensity of the airglow. This includes the Cameron bands ( a 3 Π - X 1 Σ ) of CO, the CO 2 + ultraviolet doublet ( B 2 Σ u + - X 2 Π g ) at 289.0 nm and the oxygen emission at 297.2 nm. Instrumental uncertainties of the emissions remain under 15%. Five groups of comparable orbits are selected to prepare for the data interpretation. The seasonal and solar activity effects on the dayside CO ‘Cameron Bands’, CO 2 + and OI(2972 Å) emissions are discussed in light of previous studies. These emissions exhibit for equatorial latitudes two maxima of intensity for L S = 140 ∘ and 290 ∘ (around Mars’ perihelion) and one local minimum at L S ∼ 40 ∘ . The peak at L S = 140 ∘ is corroborated by the neutral density profiles shown by Forget et al. [2008. The density and temperatures of the upper martian atmosphere measured by stellar occultations with Mars Express SPICAM. J. Geophys. Res., 1–25, submitted for publication] using SPICAM stellar occultation mode; these authors linked this sudden increase to a dust storm covering a large part of the planet, a quite unexpected event at this time of the year. A first comparison of altitude profiles of emission lines between data and the kinetic transport model shows a very similar shape and altitude peak when Viking CO 2 densities are divided by a factor 3 and uncertainties in the cross sections are taken into account. Overall intensities are, however, overestimated by our model by 25% on average for Cameron and CO 2 + emissions. The limits of the model and further improvements both on the data analysis and on the model are presented.

On the huge mass loss of B[e] supergiants in the Magellanic Clouds

AbstractB[e] supergiants are known to possess circumstellar disks in which molecules and dust can form. The formation mechanism and the resulting structure of these disks is, however, still controversial. Nevertheless, to protect the disk material from the dissociating stellar radiation and to allow for dust formation in the vicinity of a luminous supergiant star, the amount of mass comprised within these disks must be huge. We study the amount of hydrogen neutral material by means of an analysis of the strong [O i] emission lines in our optical high-resolution FEROS spectra of two B[e] supergiants, the edge-on system S 65 in the SMC, and the pole-on system R 126 in the LMC. In addition, we study the possible disk dynamics of S 65, based on a simultaneous line-profile modeling. We find that the [O i] emission lines in S 65 must originate either from an outflowing disk, in which the outflow velocity is slowly decreasing outwards, or from a Keplerian rotating ring, resulting from an ejection event.

Precise measurements of the total concentration of atmospheric CO2 and C13O2∕C12O2 isotopic ratio using a lead-salt laser diode spectrometer

We have developed a tunable diode laser spectrometer, called SIMCO (spectrometer for isotopic measurements of CO(2)), for determining the concentrations of (12)CO(2) and (13)CO(2) in atmospheric air, from which the total concentration of CO(2) and the isotopic composition (expressed in delta units) delta(13)CO(2) are calculated. The two concentrations are measured using a pair of lines around 2290.1 cm(-1), by fitting a line profile model, taking into account the confinement narrowing effect to achieve a better accuracy. Using the Allan variance, we have demonstrated (for an integration time of 25 s) a precision of 0.1 ppmv for the total CO(2) concentration and of 0.3[per thousand] for delta(13)CO(2). The performances on atmospheric air have been tested during a 3 days campaign by comparing the SIMCO instrument with a gas chromatograph (GC) for the measurement of the total CO(2) concentration and with an isotopic ratio mass spectrometer (MS) for the isotopic composition. The CO(2) concentration measurements of SIMCO are in very good agreement with the GC data with a mean difference of Delta(CO(2))=0.16+/-1.20 ppmv for a comparison period of 45 h and the linearity of the concentration between the two instruments is also very good (slope of correlation: 0.9996+/-0.0003) over the range between 380 and 415 ppmv. For delta(13)CO(2), the comparison with the MS data shows a larger mean difference of Delta(delta(13)CO(2))=(-1.9+/-1.2)[per thousand], which could be partly related to small residual fluctuations of the overall SIMCO instrument response.

Effects of Downscattering on the Continuum and Line Spectra in a Powerful Wind Environment: Monte Carlo Simulations, Analytical Results, and Data Analysis

In an earlier paper, the general formulation and results for photon reprocessing (downscattering) that included recoil and Comptonization effects due to divergence of the flow were presented. In a second paper we showed the Monte Carlo (MC) simulated continuum and line spectra. We also provided an analytical description of the simulated continuum spectra using the diffusion approximation. We have simulated the propagation of monochromatic and continuum photons in a bulk outflow from a compact object. Electron scattering of the photons within the expanding flow leads to a decrease of their energy, which is of first order in V/c (where V is the outflow velocity). The downscattering effect of first order in V/c in the diverging flow is explained by semianalytical calculations and confirmed by MC simulations. We conclude that redshifted lines and downscattering bumps are intrinsic properties of the powerful outflows for which the Thomson optical depth is greater than 1. We fitted our model line profiles to the observations using four free parameters, β = V/c, the optical depth of the wind τ, the wind temperature kTe, and the original line photon energy E0. We show how the primary spectrum emitted close to the black hole is modified by reprocessing in the warm wind. In the framework of our wind model, the fluorescent iron line Kα is formed in the partly ionized wind as a result of illumination by central source continuum photons. The demonstrated application of our outflow model to the XMM-Newton observations of MCG -6-30-15 and to the ASCA observations of GRO J1655-40 points out a potential powerful spectral diagnostic for probes of the outflow-central object connection in Galactic and extragalactic black hole sources.

Radiatively Inefficient Accretion Flow in the Nucleus of NGC 1097

We present a model for the accretion flow around the supermassive black hole in the LINER nucleus of NGC 1097 that fits the optical to X-ray spectral energy distribution (SED). The X-ray segment of the SED is based on observations with the Chandra X-Ray Observatory, which are reported here for the first time. The inner part of the flow is modeled as a radiatively inefficient accretion flow (RIAF), and the outer part as a standard thin disk. The value of the transition radius (r(tr) approximate to 225R(S), where R-S = 2GM/c(2)) between the RIAF and the outer thin disk was obtained from our previous fitting of the double-peaked Balmer emission line profile, which originates in the thin disk. The black hole mass was inferred from measurements of the stellar velocity dispersion in the host galaxy. When these parameters are used in the accretion flow model, the SED can be successfully reproduced, which shows that the line profile model and the accretion flow model are consistent with each other. A small remaining excess in the near-UV is accounted for by the contribution of an obscured starburst located within 9 pc from the nucleus, as we reported in an earlier paper. The radio flux is consistent with synchrotron emission of a relativistic jet modeled by means of the internal shock scenario. In an appendix we also analyze the Chandra X-ray observations of the similar to 1 kpc circumnuclear star-forming ring and of an ultraluminous compact X-ray source located outside the ring.