Broad Line Systems Research Articles

Galaxy and Mass Assembly (GAMA): A WISE Study of the Activity of Emission-line Systems in G23

Abstract We present a detailed study of emission-line systems in the Galaxy And Mass Assembly (GAMA) G23 region, making use of Wide-field Infrared Survey Explorer (WISE) photometry that includes carefully measured resolved sources. After applying several cuts to the initial catalog of ∼41,000 galaxies, we extract a sample of 9809 galaxies. We then compare the spectral diagnostic Baldwin, Philips & Terlevich (BPT) classification of 1154 emission-line galaxies (38% resolved in W1) to their location in the WISE color–color diagram, leading to the creation of a new zone for mid-infrared “warm” galaxies located 2σ above the star-forming sequence, below the standard WISE active galactic nucleus (AGN) region. We find that the BPT and WISE diagrams agree on the classification for 85% and 8% of the galaxies as non-AGN (star-forming = SF) and AGN, respectively, and disagree on ∼7% of the entire classified sample. Thirty-nine percent of the AGNs (all types) are broad-line systems for which the [N ii] and [Hα] fluxes can barely be disentangled, giving in most cases spurious [N ii]/[Hα] flux ratios. However, several optical AGNs appear to be completely consistent with SF in WISE. We argue that these could be low-power AGNs, or systems whose hosts dominate the IR emission. Alternatively, given the sometimes high [O iii] luminosity in these galaxies, the emission lines may be generated by shocks coming from super-winds associated with SF rather than AGN activity. Based on our findings, we have created a new diagnostic: [W1 – W2] versus [N ii]/[Hα], which has the virtue of separating SF from AGNs and high-excitation sources. It classifies 3 to ∼5 times more galaxies than the classic BPT.

SDSS J153636.22+044127.0 and Its Analogs: Shocked Outflows, Not Active Binary Black Holes

Abstract The binary emission-line system, particularly the binary broad-line emission system, is considered the most effective indicator of the black hole binary. A plausible example of such a system, SDSS J153636.22+044127.0, was reported as the first known object with two hydrogen Balmer broad-line systems, which are interpreted to be the result of broad-line regions around a pair of black holes. Here, we show the follow-up optical and near-infrared spectral observations of SDSS J153636.22+044127.0 and its analogs. In these objects, the broad hydrogen Balmer and Paschen, He i, and Mg ii lines share the same peculiar emission-line profile (including a blue system, a red system, and a double-peaked disk-line component); however, the invariance in the large time interval, the absence of the blue system in He i λ10830 profile, and the abnormally strong emission of the hydrogen Paβ blue system oppose the binary proposal. We suggest that these unique broad lines arise from the active galactic nucleus emission-line region and the shock-heated outflowing gases rather than a binary system of two active black holes.

HUBBLE SPACE TELESCOPEIMAGES AND KPNO SPECTROSCOPY OF THE BINARY BLACK HOLE CANDIDATE SDSS J153636.22+044127.0

We present Hubble Space Telescope WFPC2/PC images and KPNO 4 m long-slit spectroscopy of the QSO SDSS J153636.22+044127.0, which we advanced as a candidate binary supermassive black hole. The images reveal a close companion coincident with the radio source identified by Wrobel & Laor. It appears to be consistent with a Mg ~ –21.4 elliptical galaxy, if it is at the QSO redshift. The spectroscopy, however, shows no spatial offset between the red or blue Balmer lines. The companion is thus not the source of either the red or blue broad-line systems; SDSS J153636.22+044127.0 is highly unlikely to be a chance superposition of objects or an ejected black hole. Over the ΔT = 0.75 yr difference between the rest-frame epoch of the present and SDSS spectroscopy, we find no velocity shift to within 40 km s–1, nor any amplitude change in either broad-line system. The lack of a shift can be admitted under the binary hypothesis, if the implied radial velocity is a larger component of the full orbital velocity than was assumed in our earlier work. A strong test of the binary hypothesis requires yet longer temporal baselines. The lack of amplitude variations is unusual for the alternative explanation of this object as a double-peaked emitter; we further argue that SDSS J153636.22+044127.0 has unique spectral features that have no obvious analogue with other members of this class.

THE GROWTH OF BLACK HOLES: INSIGHTS FROM OBSCURED ACTIVE GALAXIES

Obscured or narrow-line active galaxies offer an unobstructed view of the quasar environment in the presence of a luminous and vigorously accreting black hole (BH). We exploit the large new sample of optically selected luminous narrow-line active galaxies from the Sloan Digital Sky Survey at redshifts 0.1 < z < 0.45, in conjunction with follow-up observations with the Low Dispersion Survey Spectrograph (LDSS3) at Magellan, to study the distributions of BH mass and host galaxy properties in these extreme objects. We find a narrow range in BH mass (log M BH/M ☉ = 8.0 ± 0.7) and Eddington ratio (log L bol/L Edd = –0.7 ± 0.7) for the sample as a whole, surprisingly similar to comparable broad-line systems. In contrast, we infer a wide range in star formation properties and host morphologies for the sample, from disk-dominated to elliptical galaxies. Nearly one-quarter have highly disturbed morphologies indicative of ongoing mergers. Unlike the BHs, which are apparently experiencing significant growth, the galaxies appear to have formed the bulk of their stars at a previous epoch. On the other hand, it is clear from the lack of correlation between gaseous and stellar velocity dispersions in these systems that the host galaxy interstellar medium is far from being in virial equilibrium with the stars. While our findings cast strong doubt on the reliability of substituting gas for stellar dispersions in high luminosity active galaxies, they do provide direct evidence that luminous accreting BHs influence their surroundings on a galaxy-wide scale.

The optical emission line spectrum of Mark 110

We analyse in detail the rich emission line spectrum of Mark 110 to determine the physical conditions in the nucleus of this object, a peculiar NLS1 without any detectable Fe II emission associated with the broad line region and with a $\lambda5007/H\beta$ line ratio unusually large for a NLS1. We use 24 spectra obtained with the Marcario Low Resolution Spectrograph attached at the prime focus of the 9.2 m Hobby-Eberly telescope at the McDonald observatory. We fitted the spectrum by identifying all the emission lines (about 220) detected in the wavelength range 4200-6900 \AA (at rest). The emission lines are probably produced in a region with a density gradient in the range 10$^{3}-10^{6}$ cm$^{-3}$ with a rather high column density (5$\times10^{21}$ cm$^{-2}$). In addition to a line system, three major broad line systems with different line velocity and width are required. We confirm the absence of broad Fe II emission lines. We speculate that Mark 110 is in fact a BLS1 with relatively narrow broad lines but with a BH mass large enough compared to its luminosity to have a lower than Eddington luminosity.

Motion in the Orion nebula - A kinematic study of forbidden S III

Slit spectra of [S III] 631.2 nm emission were used to map the velocity structure of the inner few arcminutes of M42. The resolution of the spectra, 5 km s −1 , is high enough so that different velocity components in a line profile can be resolved. We found evidence for the existence of four velocity systems, a high flux system (A), a low-velocity system (B), a broad line system (C), and a high-velocity system (D). System A has a velocity flow pattern that is similar to those of [O I] and the main emission component of [O III]. A detailed statistical analysis was carried out for only system A, which has less errors and uncertainties than the others. The average line width is about 12 km s −1 , implying a turbulent motion line width of 11 km s −1

The Structure of the Envelopes of Symbiotic Novae

Symbiotic novae are composite spectrum stars whose light history is characterized by one single major outburst. At high resolution their optical and UV spectra are very rich of emission lines belonging to a wide ionization range. Generally one can identify both narrow and broad line systems. The latter includes emission lines with multiple structure, broad emission wings, WR features, and P Cygnl lines. Frequently the broad line profiles are largely variable with time. They should be associated with the major stellar outburst. An overview of the problem with extensive references can be found in Viotti (1989).