We present the results of optical spectral analysis of a sample of 155 bright X ray selected ROSAT Seyfert 1 type AGN. We measured emission line properties by performing multi component fits to the emission line profi...We present the results of optical spectral analysis of a sample of 155 bright X ray selected ROSAT Seyfert 1 type AGN. We measured emission line properties by performing multi component fits to the emission line profiles, covering the effect of blended iron emission. We also obtained continuum parameters, including 250eV X ray luminosities derived from the ROSAT database. The measured properties are gathered for correlation analysis. Strong correlations between Hβ redshift, flux ratios of Fe Ⅱ to Hβ broad component and to Hβ narrow component are found. The observed trends are most likely driven by the Eddington ratio.展开更多
We present the discovery of 18 narrow line Seyfert 1 galaxies (NLS1). The optical spectra show the Balmer lines only slightly broader than the forbidden lines and contain strong Fe Ⅱ emission. No particularly soft X ...We present the discovery of 18 narrow line Seyfert 1 galaxies (NLS1). The optical spectra show the Balmer lines only slightly broader than the forbidden lines and contain strong Fe Ⅱ emission. No particularly soft X ray spectral slopes can be seen compared to a normal Seyfert 1 galaxies sample.展开更多
We found a NLS1 nucleus in the extensively studied eruptive BL Lac object, 0846+51W1, out of a large sample of NLS1s compiled from the spectroscopic dataset of SDSS DR1. Its optical spectrum can be well decomposed int...We found a NLS1 nucleus in the extensively studied eruptive BL Lac object, 0846+51W1, out of a large sample of NLS1s compiled from the spectroscopic dataset of SDSS DR1. Its optical spectrum can be well decomposed into three components: a power law component from the relativistic jet, a stellar component from the host galaxy, and a component from a typical NLS1 nucleus. The emission line properties of 0846+51W1, FWHM (Hβ) (?) 1710 km s-1 and [OⅢ]λ5007/Hβ(?)0.32 from its SDSS spectrum observed when it was in the faint state, fulfil the conventional definition of NLS1. Strong Fell emission is detected in the SDSS spectrum, which is also typical of NLS1s. We tried to estimate its central black hole mass using various techniques and found that 0846+51W1 is very likely emitting at a few ×10% of the Eddington luminosity. We speculate that Seyfert-like nuclei, including NLS1s, might be concealed in a significant fraction of BL Lacs but have remained largely unobserved because, often, their optical-UV continuum is overwhelmed by the synchrotron emission.展开更多
We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest(> 30 ks) observations made for NGC 4051, MCG-06–30–15 and NGC 4151 by ...We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest(> 30 ks) observations made for NGC 4051, MCG-06–30–15 and NGC 4151 by XMM-Newton between 2000 and 2015. The nuclei were quite active during essentially all of these observations and the overall X-ray fluxes(0.3–10 keV) varied by an order of magnitude. Most of the observations do appear to show characteristic timescales, estimated through their auto-correlation functions, ranging between ~2.9 ks and ~45.3 ks. The hard(2–10 keV) and soft(0.3–2.0 keV) bands are very well correlated but consideration of their hardness ratios shows that the sources typically soften during flares. We also provide new estimates of the central black hole masses for these three AGNs that support the hypothesis that Narrow Line Seyfert 1 galaxies have relatively small central black holes.展开更多
文摘We present the results of optical spectral analysis of a sample of 155 bright X ray selected ROSAT Seyfert 1 type AGN. We measured emission line properties by performing multi component fits to the emission line profiles, covering the effect of blended iron emission. We also obtained continuum parameters, including 250eV X ray luminosities derived from the ROSAT database. The measured properties are gathered for correlation analysis. Strong correlations between Hβ redshift, flux ratios of Fe Ⅱ to Hβ broad component and to Hβ narrow component are found. The observed trends are most likely driven by the Eddington ratio.
文摘We present the discovery of 18 narrow line Seyfert 1 galaxies (NLS1). The optical spectra show the Balmer lines only slightly broader than the forbidden lines and contain strong Fe Ⅱ emission. No particularly soft X ray spectral slopes can be seen compared to a normal Seyfert 1 galaxies sample.
文摘We found a NLS1 nucleus in the extensively studied eruptive BL Lac object, 0846+51W1, out of a large sample of NLS1s compiled from the spectroscopic dataset of SDSS DR1. Its optical spectrum can be well decomposed into three components: a power law component from the relativistic jet, a stellar component from the host galaxy, and a component from a typical NLS1 nucleus. The emission line properties of 0846+51W1, FWHM (Hβ) (?) 1710 km s-1 and [OⅢ]λ5007/Hβ(?)0.32 from its SDSS spectrum observed when it was in the faint state, fulfil the conventional definition of NLS1. Strong Fell emission is detected in the SDSS spectrum, which is also typical of NLS1s. We tried to estimate its central black hole mass using various techniques and found that 0846+51W1 is very likely emitting at a few ×10% of the Eddington luminosity. We speculate that Seyfert-like nuclei, including NLS1s, might be concealed in a significant fraction of BL Lacs but have remained largely unobserved because, often, their optical-UV continuum is overwhelmed by the synchrotron emission.
基金funded by ESA Member States and NASAsupport from the China Scholarship Council (CSC, Grant 2016GXZR89)+2 种基金supported by the Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (PIFI, Grant 2016VMB073)supported by the National Natural Science Foundation of China (Grant Nos. 11873073, 11473054 and U1531245)by the Science and Technology Commission of Shanghai Municipality (14ZR 1447100)
文摘We present and analyze the variability of three Seyfert galaxies on intra-day timescales. We have analyzed in a uniform manner the 38 longest(> 30 ks) observations made for NGC 4051, MCG-06–30–15 and NGC 4151 by XMM-Newton between 2000 and 2015. The nuclei were quite active during essentially all of these observations and the overall X-ray fluxes(0.3–10 keV) varied by an order of magnitude. Most of the observations do appear to show characteristic timescales, estimated through their auto-correlation functions, ranging between ~2.9 ks and ~45.3 ks. The hard(2–10 keV) and soft(0.3–2.0 keV) bands are very well correlated but consideration of their hardness ratios shows that the sources typically soften during flares. We also provide new estimates of the central black hole masses for these three AGNs that support the hypothesis that Narrow Line Seyfert 1 galaxies have relatively small central black holes.