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Register a new userIs there a connection between Broad Absorption Line Quasars and Narrow Line Seyfert 1 galaxies?
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We consider whether Broad Absorption Line Quasars (BAL QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt & Gallagher (2000) and Boroson (2002). For this purpose we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/Ledd, although BAL QSOs have slightly lower L/Ledd. BAL QSOs and NLS1s in general have high FeII/H$beta$ and low [OIII]/H$beta$ ratios following the classic Boroson & Green eigenvector 1 relation. We also found that the mass accretion rates $dot{M}$ of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 msun/year. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M-$sigma$ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample we find eigenvector 1 to correspond to the Eddington ratio L/Ledd, and eigenvector 2 to black hole mass.
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We studied optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z<0.8 to investigate any differences in their OV properties. Using archival optical V-band light curves from the Catalina Real Time Transient Survey that span 5-9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe II strength but correlated with the width of the H-beta line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power suggesting jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.
We report the first systematic search for blazars among broad-absorption-line (BAL) quasars. This is based on our intranight optical monitoring of a well-defined sample of 10 candidates selected on the criteria of a flat spectrum and an abnormally high linear polarization at radio wavelengths. A small population of BAL blazars can be expected in the polar model of BAL quasars. However, no such case is found, since none of our 30 monitoring sessions devoted to the 10 candidates yielded a positive detection of intra-night optical variability (INOV), which is uncharacteristic of blazars. This lack of INOV detection contrasts with the high duty cycle of INOV observed for a comparison sample of 15 normal (i.e., non-BAL) blazars. Some possible implications of this are pointed out.
Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the H$beta$ broad emission line < 2000 km/s and the flux ratio of [O III] to H$beta$ < 3. Their properties are not well understood since only a few NLSy1 galaxies were known earlier. We have studied various properties of NLSy1 galaxies using an enlarged sample and compared them with the conventional broad-line Seyfert 1 (BLSy1) galaxies. Both the sample of sources have z $le$ 0.8 and their optical spectra from SDSS-DR12 that are used to derive various physical parameters have a median signal to noise (S/N) ratio >10 per pixel. Strong correlations between the H$beta$ and H$alpha$ emission lines are found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of H$beta$, H$alpha$ and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the $R_{4570}$ - $xi_{Edd}$ diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R > 10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 $pm$ 0.9) than BLSy1 galaxies (2.4 $pm$ 0.8). It is anti-correlated with the H$beta$ width but correlated with the Fe II strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.
We present a detailed comparative systematic study using a sample of 221 Narrow-line Seyfert 1 (NLSy1) galaxies in comparison to a redshift matched sample of 154 Broad-line Seyfert 1 (BLSy1) galaxies based on their observations using ROSAT and/or XMM-Newton telescopes in soft X-ray band (0.1-2.0 keV). A homogeneous analysis is carried out to estimate their soft X-ray photon indices ($Gamma^{s}_{X}$) and its correlations with other parameters of nuclear activities such as Eddington ratios (R$_mathrm{Edd}$), bolometric luminosities (L$_mathrm{bol}$), black hole masses (M$_mathrm{BH}$) and the widths of the broad component of H$beta$ lines (FWHM(H$beta$)). In our analysis, we found clear evidence of the difference in the $Gamma^{s}_{X}$ and R$_mathrm{Edd}$ distributions among NLSy1 and BLSy1 galaxies, with steeper $Gamma^{s}_{X}$ and higher R$_mathrm{Edd}$ for the former. Such a difference also exists in the spectral indices distribution in hard X-ray ($Gamma^{h}_{X}$), based on the analysis of 53 NLSy1 and 46 BLSy1 galaxies in the 2-10 keV energy band. The difference in R$_mathrm{Edd}$ distributions does exist even after applying the average correction for the difference in the inclination angle of NLSy1 and BLSy1 galaxies. We also estimated R$_mathrm{Edd}$, based on SED fitting of 34 NLSy1 and 30 BLSy1 galaxies over the 0.3-10 keV energy band and found that results are still consistent with R$_mathrm{Edd}$ estimates based on the optical bolometric luminosity. Our analysis suggests that the higher R$_mathrm{Edd}$ in NLSy1 is responsible for its steeper X-ray spectral slope compared to the BLSy1, consistent with the disc-corona model as proposed for the luminous AGNs.
We present a detailed study of 11 narrow-line Seyfert 1 galaxies (NLS1s) from the Six-degree Field Galaxy Survey (6dFGS) that both have optical and X-ray spectroscopic observations. There are five complex NLS1s (C-NLS1s) and six simple NLS1s (S-NLS1s). We propose a possible correlation between [O III] line asymmetry and X-ray complexity. The outflow or wind from the inner accretion disk is commonly present in NLS1s and mostly directed along the system axis. In C-NLS1s only weak wind effects are measured, the X-ray spectral complexity might be caused by the presence of ionized material in the wind. On the contrary, the wind in S-NLS1s is fast, the ionized material could be swept by such a strong wind, thus the complex feature is missing which results in a simple X-ray spectrum. Furthermore, this outflow scenario seems to be an inclination effect. Since the speed of the wind is higher in a small inclination while lower in a large inclination, S-NLS1s might be sources viewed at small angles while C-NLS1s might be sources viewed at large angles.
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