H-beta Profile Research Articles

Is MgIIλ2800 a reliable virial broadening estimator for quasars?

[Abridged] Broad MgII 2800 and Hbeta lines have emerged as the most reliable virial estimators of black hole mass in quasars. Which is more reliable? Comparison of MgII 2800 and Hbeta profile measures in the same sources and especially FWHM measures that provide the virial broadening estimator. Identification of 680 bright Sloan Digital Sky Survey DataRelease 7 quasars with spectra showing both MgII 2800 and Hbeta lines, at redshift 0.4 < z < 0.75. The s/n of these spectra are high enough to allow binning in the "four-dimensional (4D) eigenvector 1'' optical plane and construction of high s/n composite spectra. We confirm that MgII 2800 shows a profile that is ~ 20% narrower as suggested in some previous studies. FWHM measures for Population B sources (i.e., with FWHM of Hbeta larger than 4000 km/s) are uncertain because they show complex profiles with at least two broad-line components involving a nearly unshifted broad and redshifted very-broad component. Only the broad component is likely to be a valid virial estimator. If Hbeta and MgII 2800 are not corrected for the very broad component then black hole mass values for Population B sources will be systematically overestimated by up to logM ~ 0.3-0.4 dex. We suggest a simple correction that can be applied to the majority of sources. MgII 2800 is the safer virial estimator for Population B sources because the centroid shifts with respect to rest frame are lower than for Hbeta. In the broad and very broad component profile interpretation this is a consequence of the lower very broad to broad component intensity ratio for MgII 2800. Effective discrimination of black hole mass and Eddington ratio at fixed redshift is not achieved via luminosity binning but rather by binning in a "4D eigenvector 1'' context that reflects different broad line region geometry/kinematics likely driven by Eddington ratio.

A LARGE SYSTEMATIC SEARCH FOR CLOSE SUPERMASSIVE BINARY AND RAPIDLY RECOILING BLACK HOLES

[ABRIDGED] We have carried out a systematic search for close supermassive black hole binaries among z < 0.7 SDSS quasars Such binaries are predicted by models of supermassive black hole and host galaxy co-evolution, therefore their census and population properties constitute an important test of these models. We used an automatic technique based on spectroscopic principal component analysis to search for broad H-beta lines that are displaced from the rest-frame of the quasar by more than 1,000 km/s This method can also yield candidates for rapidly recoiling black holes. Our search yielded 88 candidates, several of which were previously identified and discussed in the literature. The widths of the broad H-beta lines are typical among quasars but the shifts are extreme. We found a correlation between the peak offset and skewness of the broad H-beta profiles, which suggests that the profiles we have selected share a common physical explanation. The general properties of the narrow emission lines are typical of quasars. We carried out followup spectroscopic observations of 68 objects to search for changes in the peak velocities of the H-beta lines (the time interval in the observer's frame between the original and new observations is 1-10 yr). We measured significant changes in 14 objects, with resulting accelerations between -120 and +120 km/s/yr. We emphasize that interpretation of the offset broad emission lines as signatures of supermassive binaries is subject to many significant caveats. Many more followup observations over a long temporal baseline are needed to characterize the variability pattern of the broad lines and test that this pattern is indeed consistent with orbital motion. The possibility that some of the objects in this sample are rapidly recoiling black holes remains open as the available data do not provide strong constraints for this scenario.

THE QUASAR SDSS J105041.35+345631.3: BLACK HOLE RECOIL OR EXTREME DOUBLE-PEAKED EMITTER?

The quasar SDSS J105041.35+345631.3 (z = 0.272) has broad emission lines blueshifted by 3500 km/s relative to the narrow lines and the host galaxy. Such an object may be a candidate for a recoiling supermassive black hole, binary black hole, a superposition of two objects, or an unusual geometry for the broad emission-line region. The absence of narrow lines at the broad line redshift argues against superposition. New Keck spectra of J1050+3546 place tight constraints on the binary model. The combination of large velocity shift and symmetrical H-beta profile, as well as aspects of the narrow line spectrum, make J1050+3546 an interesting candidate for black hole recoil. Other aspects of the spectrum, however, suggest that the object is most likely an extreme case of a ``double-peaked emitter.'' We discuss possible observational tests to determine the true nature of this exceptional object.

Unique broad-line profile variations in the radio galaxy 3C 390.3

The results of a variability study of the flux and profile of H-beta in 3C 390.3 are presented. Spectra of this object were obtained at 39 epochs during the years 1974-1988. It is shown that the fluctuations of the H-beta flux closely mimic the variations of the optical continuum during that period. The time scale for the emission-line variations is shorter than a year, and perhaps as short as a month. The blue side of the H-beta profile ('blue bump') also followed closely the continuum variations, but the red side ('red bump') did not. The ratio of the fluxes of the blue and red bumps behaved in a very regular, nearly sinusoidal fashion. It reached a maximum in mid-1975 and at the end of 1985, a time interval of 10.4 yr. The velocity of the peak of the blueshifted bump drifted by +900 km/s during the 14-yr interval covered by the observations. 103 refs.

OX 169 - Evidence for a recent merger

view Abstract Citations (36) References (41) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS OX 169: Evidence for a Recent Merger Stockton, Alan ; Farnham, Tony Abstract New imaging observations in the optical, IR, and radio, as well as the results of spectroscopy, are presented for the nucleus and jet of the luminous QSO OX 169. The luminosity of the jet is clearly of stellar origin, and the feature is apparently a planar distribution of stars seen edge-on. Significant differences are apparent in the H-beta profile between spectra of OX 169 obtained in 1983 and 1989: while a relativistic disk model is an excellent fit to the 1989 profile, no such profile can fit the 1983 profile unless azimuthal asymmetries are introduced. These differential variations are used to perform a rough deconvolution of the profile and to show that the broad-line radiation probably arises in two essentially independent regions. A supermassive binary, each component with its own broad-line region, is an attractive model for OX 169. Publication: The Astrophysical Journal Pub Date: April 1991 DOI: 10.1086/169916 Bibcode: 1991ApJ...371..525S Keywords: Galactic Structure; Quasars; Radio Galaxies; Radio Jets (Astronomy); Astronomical Spectroscopy; Balmer Series; Brightness Distribution; Radio Astronomy; Astrophysics; GALAXIES: INDIVIDUAL ALPHANUMERIC: OX 169; GALAXIES: JETS; GALAXIES: STRUCTURE; QUASARS; RADIO SOURCES: GALAXIES full text sources ADS | data products SIMBAD (8) NED (1)

A double-stream model for line profiles

It is shown that gas clouds in a biconical shape may produce profiles similar to those produced in a spherical geometry. The profile shape depends on the radial velocity field, the projection angle, and most importantly, the shell luminosity distribution. If the conical region extends over a large range of radial distances, the resultant profile may be symmetrical with logarithmic wings. It is shown that the double-peaked H-beta profile in Akn 120 can be modeled with a double-stream model. 26 refs.

An analysis of LTE effects in inductively coupled RF plasmas

Spectroscopic measurements are carried out on inductively coupled radio-frequency (RF) argon plasma over the pressure range 120 to 760 Torr. The electron number density is obtained by two methods: Hbeta profile and the absolute intensity of the argon continuum. Number densities of excited argon levels are deduced from absolute line intensities. The electron density measured in the hottest zone of the plasma decreases from 1016 to 6*1015 cm-3 with the decrease of pressure from 760 to 120 Torr. Comparison between the different number densities shows that the atmospheric plasma is in local thermodynamic equilibrium (LTE) whereas weak departures from equilibrium are observed at pressures below 300 Torr.

Nuclear emission-line intensities and profiles in NGC 3783

High-resolution optical spectrophotometry is presented for the nucleus of the Seyfert 1 galaxy NGC 3783. The data suggest that the broadest components of the forbidden lines have blueshifts relative to systemic velocity which are correlated primarily with ionization potential, and FWHMs which are correlated primarily with criticl density. Similar trends also exist in the line components responsible for the larger part of the line emission, but are not as strong as for the broadest line components. Comparison of the profiles of the Balmer lines indicates that the Balmer decrement measured from the H-beta/H-alpha ratio flattens in the line wings. However, the H-gamma and H-delta line profiles are more similar to the H-alpha line profile than to the H-beta line profile, suggesting that the H-beta profile may be anomalous.

Profiles and profile ratios in Seyfert I galaxies

view Abstract Citations (59) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Profiles and Profile Ratios in Seyfert 1 Galaxies Crenshaw, D. Michael Abstract The authors have obtained high signal-to-noise spectra of Seyfert 1 galaxies in order to study the broad emission line profiles. Three contamination effects that tend to weaken the core or strengthen the wings of the H-beta profile relative to the H-alpha profile are considered. Despite corrections applied to the profiles for these effects, the H-beta/H-alpha ratio increases dramatically with the absolute value of the radial velocity in eight of the nine galaxies studied. From a comparison of these profile ratios among individual Seyfert 1 galaxies, it is found that the broad-line region clouds are in a roughly spherical distribution around the photoionizing continuum source. If H-beta/H-alpha and He I 5816 A/H-beta increase primarily with the ionizing flux, as recent photoionization models suggest, then clouds closer to the continuum source must have higher velocities on average. Finally, the large increase in H-beta/H-alpha and He I/H-beta from the core to the wings indicates that the broad-line region is not a thin spherical shell. Publication: The Astrophysical Journal Supplement Series Pub Date: December 1986 DOI: 10.1086/191156 Bibcode: 1986ApJS...62..821C Keywords: Astronomical Spectroscopy; Line Spectra; Seyfert Galaxies; Continuous Spectra; H Alpha Line; H Beta Line; Luminosity; Spectral Line Width; Astrophysics; GALAXIES: SEYFERT; LINE PROFILES full text sources ADS | data products NED (12) SIMBAD (9)

Optical and UV spectroscopy of the peculiar RS CVn system RT Lacertae

H-alpha and H-beta spectra of the peculiar double-lined RS CVn binary RT Lacertae have been obtained using the IUE, together with a ground-based coude-feed telescope at KPNO. The ground-based spectra show an asymmetry related to the orbital phase in the H-alpha profile. H-beta profiles showed excess emission in one hemisphere and excess absorption in the other, with a broad Gaussian emission component superposed on the excess H-alpha line. A radial velocity curve was derived to estimate the mass ratio and geometry of the system. It is shown that the component of RT Lac fills 80-90 percent of the equilibrium Roche surface. Low-resolution ultraviolet data show that the supposed cooler component is bluer than its companion, suggesting evidence of a scattering shell or a cloud produced by the splash of a gas stream. The phase behavior of the low resolution ultraviolet data support the conclusion that RT Lac is a mass transfer system and that mass transfer is the primary cause of its activity.

EVIDENCE FOR A LOW-DENSITY COMPONENT IN THE BROAD-LINE REGION OF SEYFERT GALAXIES.

ABSTRACT It is found that the forbidden 4959-5007 A broad O III lines, good candidates for the excess shelf emission, are found in the vicinity of H-beta in Seyfert 1 galaxy spectra. The shelf-study method used to remove Fe II assumes that the profiles of the contributors to the shelf are known, and that subtraction of these contributors in the correct amount will result in a fairly smooth H-beta profile. Data were obtained with the Ohio State University Image-Dissector Scanner with a 600 line/mm grating, on a 1.8-m reflector. The estimated cloud electron density of 1 billion/sq cm is at the low end of those used for BLR photoionization models. The presence of a broad residual emission feature in the neighborhood of 5050 A after subtraction of the shelf is thought to be the result of a weak broad emission in this range from yet another species.

ON THE ASYMMETRY OF BROAD-LINE H-BETA EMISSION IN SEYFERT 1 GALAXIES.

ABSTRACT It is argued that the asymmetric appearance of the broad H-beta emission line in Seyfert 1 galaxies is due to contamination of the red wing of H-beta by lines of other species. It is further argued that emission due to Fe II at 4924 and 5018 angstroms alone is insufficient to explain the observed asymmetry. Broad forbidden O III line 4959- and 5007-angstrom emission is suggested as a possible contributor, and it is shown that the H-beta profile of Akn 120 can be modeled with broad symmetric lines of H-beta combined with the above mentioned lines of forbidden O III line and Fe II.

The time variation of broad emission-line profiles of Seyfert 1 galaxies

view Abstract Citations (76) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The time variation of broad emission-line profiles of Seyfert 1 galaxies Capriotti, E. R. ; Foltz, C. B. ; Peterson, B. M. Abstract Broad-line profiles have been calculated for models of the emitting region of Seyfert 1 galaxies in which the emitting clouds are in radial outflow. The continuum source is assumed to vary on a time scale a bit shorter than the light-travel time through the broad-line emitting region. The combination of a variable continuum source and light-travel time considerations produces the following effects: the calculated profiles have considerable structure which is introduced by continuum variations; the calculated profiles can be asymmetric in the sense often observed in Seyfert 1 spectra even if the clouds are assumed to emit line radiation isotropically; and the variation of the H-beta profiles of Arakelian 120 is roughly reproduced by the calculations. Publication: The Astrophysical Journal Pub Date: October 1982 DOI: 10.1086/160315 Bibcode: 1982ApJ...261...35C Keywords: Emission Spectra; Seyfert Galaxies; Spectral Line Width; Doppler Effect; H Beta Line; Spectrum Analysis; Astrophysics full text sources ADS | data products NED (1)

SPECTROSCOPY OF THE DWARF NOVA RX AND AT MINIMUM.

ABSTRACT Spectrographic data on the dwarf nova RX Andromedae obtained on three consecutive nights when the nova was in a low state is analyzed. The spectra cover 50% of the orbit cycle in the region 3800-5000 A at 1.5-A resolution and time resolution of about 0.03 in phase. Peak radial velocities measured from all line features in all spectra are observed to form a sequence at higher velocities at phases from 0.9 to 0.2. Orbital solutions derived from the radial velocity data indicate a period somewhat shorter than that found by Kraft (1962), suggesting a period change at a rate of 0.000045 per year. Data also reveal no evidence for Kraft's value of 0.40 for the eccentricity. Spectra exhibit late-type secondary features, a wing asymmetry in the H-beta profiles, and certain weak emission features.

Radio and optical observations of SS 433

Results are presented for radio and limited optical spectroscopic observations of the peculiar emission variable star SS 433, which appears to be associated with the X-ray source A1909+04 and the supernova remnant W50. The radio source is nonthermal and shows clear evidence for variability on a time scale as short as a few hours. Neither linear nor circular polarization was detected. The optical spectra indicate intense Balmer and other lines superimposed on a red continuum, with evidence for variability in the H-beta profile. The significance of these observations is briefly discussed.

Spectrophotometry of Seyfert 1 galaxies

view Abstract Citations (526) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectrophotometry of Seyfert 1 galaxies. Osterbrock, D. E. Abstract Relative emission-line intensities measured from image-tube/image-dissector spectral scans performed with a resolution of approximately 10 A are presented for 36 Seyfert 1 galaxies. The emission-line intensities are linked to the continuum by measuring the equivalent width of H-beta, the relative intensities for the Seyfert 1 galaxies are compared with those for five broad-line radio galaxies, and each Seyfert is classified into one of four groups on the basis of the appearance of its H-beta profile. It is shown that the broad-line radio galaxies generally have larger H-alpha/H-beta ratios and steeper Balmer gradients than the Seyferts, that the He I 5876-A and He II 4686-A lines in the Seyferts have widths comparable to those of the H I lines, and that the He abundances are approximately normal in most Seyfert 1 and broad-line radio galaxies. Nearly every Seyfert is found to have measurable Fe II emission, but a wide intensity range is observed. Publication: The Astrophysical Journal Pub Date: August 1977 DOI: 10.1086/155407 Bibcode: 1977ApJ...215..733O Keywords: Emission Spectra; H Lines; Radio Galaxies; Seyfert Galaxies; Spectral Line Width; Spectrophotometry; Abundance; Astronomical Photometry; Astronomical Spectroscopy; H Alpha Line; H Beta Line; Helium; Radio Spectra; Tables (Data); Astrophysics full text sources ADS | data products NED (37)

Stark shift in ionized boron

Stark shift of the B II line at 3451 A due to plasma microfields was measured in a luminous shock tube. Line profiles, photographically recorded in second order, were compared with closeby wavelength fiduciaries from low-pressure rare-gas lamps. Electron densities for each exposure were found by fitting H-beta profiles to theoretical line shapes. Results, estimated reliable to 25-30%, are compared with theoretical predictions.

A theoretical study of the effects of ion motion on spectral lines in plasmas. II. Hydrogen-Hβ

For pt. I see ibid., vol.6, 1044 (1973). Calculations of the plasma broadened Hbeta profile including ion dynamics are presented. The effects on the line profile of the random phase approximation for the plasma subsystem is examined. Comparisons are made to theory and experiment and a discussion of the asymmetry of the profiles is given.