909 research outputs found

    SDSS J143030.22-001115.1: A misclassified narrow-line Seyfert 1 galaxy with flat X-ray spectrum

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    We used multi-component profiles to model Hβ\beta and [O III]λλ\lambda \lambda 4959,5007 lines for SDSS J143030.22-001115.1, a narrow-line Seyfert 1 galaxy (NLS1) in a sample of 150 NLS1s candidates selected from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR). After subtracting the Hβ\beta contribution from narrow line regions (NLRs), we found that its full width half maximum (FWHM) of broad Hβ\beta line is nearly 2900 \kms, significantly larger than the customarily adopted criterion of 2000 \kms. With its weak Fe II multiples, we think that SDSS J143030.22-001115.1 can't be classified as a genuine NLS1. When we calculate the virial black hole masses of NLS1s, we should use the Hβ\beta linewidth after subtracting the Hβ\beta contribution from NLRs.Comment: 7 pages, 1 table, accepted by ChJA

    A Complete Sample of Soft X-ray Selected AGN: II. Statistical Analysis

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    Direct correlations and a Principal Component Analysis (PCA) are presented for a complete sample of 110 soft X-ray selected AGN of which about half are Narrow-Line Seyfert 1 galaxies (NLS1s). The direct correlation analyses show that narrower FWHM(H-beta) correlates with steeper X-ray spectrum, stronger optical FeII emission, weaker [OIII] emission and stronger short-term X-ray variability. This direct correlation analysis and the PCA confirm the Boroson & Green (1992) Eigenvector 1 relationship for AGN: FeII strength anti-correlates with [OIII] line strength. Eigenvector 1 is well-correlated with the Eddington luminosity ratio L/L_Edd while Eigenvector 2 shows a very good correlation with the mass of the central black hole and the mass accretion rate. The Eddington ratio L/L_Edd correlates with the X-ray spectral index alpha-X and the black home mass anti-correlates with the X-ray variability chi^2/nu. The Eddington ration L/L_Edd may be interpreted as the age of an AGN: AGN with steep X-ray spectra, strong FeII, and weak [OIII] are AGN in an early phase of their evolution. In this hypothesis NLS1s are young AGN.Comment: Accepted for publication in AJ (April 2004), 21 pages, 13 figure

    Eddington Accretion and QSO Emission Lines at z ~ 2

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    Broad Absorption Line (BAL) QSOs have been suggested to be youthful super-accretors based on their powerful radiatively driven absorbing outflows and often reddened continua. To test this hypothesis, we observed near IR spectra of the Hβ\beta region for 11 bright BAL QSOs at redshift z ~ 2. We measured these and literature spectra for 6 BAL QSOs, 13 radio-loud and 7 radio-quiet non-BAL QSOs. Using the luminosity and Hβ\beta broad line width to derive black hole mass and accretion rate, we find that both BAL and non-BAL QSOs at z ~ 2 tend to have higher L/LEddL/L_{Edd} than those at low z -- probably a result of selecting the brightest QSOs. However, we find that the high z QSOs, in particular the BAL QSOs, have extremely strong Fe II and very weak [O III], extending the inverse relationship found for low z QSOs. This suggests that, even while radiating near LEddL_{Edd}, the BAL QSOs have a more plentiful fuel supply than non-BAL QSOs. Comparison with low z QSOs shows for the first time that the inverse Fe II -- [O III] relationship is indeed related to L/LEddL/L_{Edd}, rather than black hole mass.Comment: 18 pages including 5 figures and 1 table. Accepted by the Astrophysical Journal Letter

    Tidal Disruption of a Star By a Black Hole : Observational Signature

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    We have modeled the time-variable profiles of the Halpha emission line from the non-axisymmetric disk and debris tail created in the tidal disruption of a solar-type star by a million solar mass black hole. Two tidal disruption event simulations were carried out using a three dimensional relativistic smooth-particle hydrodynamic code, to describe the early evolution of the debris during the first fifty to ninety days. We have calculated the physical conditions and radiative processes in the debris using the photoionization code CLOUDY. We model the emission line profiles in the period immediately after the accretion rate onto the black hole became significant. We find that the line profiles at these very early stages of the evolution of the post-disruption debris do not resemble the double peaked profiles expected from a rotating disk since the debris has not yet settled into such a stable structure. As a result of the uneven distribution of the debris and the existence of a ``tidal tail'' (the stream of returning debris), the line profiles depend sensitively on the orientation of the tail relative to the line of sight. Moreover, the predicted line profiles vary on fairly short time scales (of order hours to days). Given the accretion rate onto the black hole we also model the Halpha light curve from the debris and the evolution of the Halpha line profiles in time.Comment: 20 pages, 9 figures, to appear in ApJ, 1 August 2004 issue; mpeg simulations of tidal disruption available at http://www.astro.psu.edu/users/tamarab/tdmovies.htm

    Optical Properties of Radio-selected Narrow Line Seyfert 1 Galaxies

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    We present results from the analysis of the optical spectra of 47 radio-selected narrow-line Seyfert 1 galaxies (NLS1s). These objects are a subset of the First Bright Quasar Survey (FBQS) and were initially detected at 20 cm (flux density limit ~1 mJy) in the VLA FIRST Survey. We run Spearman rank correlation tests on several sets of parameters and conclude that, except for their radio properties, radio-selected NLS1 galaxies do not exhibit significant differences from traditional NLS1 galaxies. Our results are also in agreement with previous studies suggesting that NLS1 galaxies have small black hole masses that are accreting very close to the Eddington rate. We have found 16 new radio-loud NLS1 galaxies, which increases the number of known radio-loud NLS1 galaxies by a factor of ~5.Comment: 18 pages, 20 figures, Accepted for publication in Ap

    Probing the Ionizing Continuum of Narrow-Line Seyfert 1 Galaxies. I.Observational Results

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    We present optical spectra and emission-line ratios of 12 Narrow-Line Seyfert 1 (NLS1) galaxies that we observed to study the ionizing EUV continuum. A common feature in the EUV continuum of active galactic nuclei is the big blue bump (BBB), generally associated with thermal accretion disk emission. While Galactic absorption prevents direct access to the EUV range, it can be mapped by measuring the strength of a variety of forbidden optical emission lines that respond to different EUV continuum regions. We find that narrow emission-line ratios involving [OII]3727, Hbeta, [OIII]5007, [OI]6300, Halpha,[NII]6583, and [SII]6716,6731 indicate no significant difference between NLS1s and Broad-Line Seyfert 1 (BLS1) galaxies, which suggests that the spectral energy distributions of their ionizing EUV - soft X-ray continua are similar. The relative strength of important forbidden high ionization lines like [NeV]3426 compared to HeII4686 and the relative strength of [FeX]6374 appear to show the same range as in BLS1 galaxies. However, a trend of weaker F([OI]6300)/F(Halpha) emission-line ratios is indicated for NLS1s compared to BLS1s. To recover the broad emission-line profiles we used Gaussian components. This approach indicates that the broad Hbeta profile can be well described with a broad component (FWHM = 3275 +- 800 km/s) and an intermediate broad component (FWHM = 1200 +- 300 km/s). The width of the broad component is in the typical range of normal BLS1s. The emission-line flux that is associated with the broad component in these NLS1s amounts to at least 60% of the total flux. Thus it dominates the total line flux, similar to BLS1 galaxies.Comment: 34 pages, 9 figures. accepted for publication in the Astrophys.Journa

    The rise of an ionized wind in the Narrow Line Seyfert 1 Galaxy Mrk 335 observed by XMM-Newton and HST

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    We present the discovery of an outflowing ionized wind in the Seyfert 1 Galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not known to host warm absorber gas until recent XMM-Newton observations in combination with a long-term Swift monitoring program have shown extreme flux and spectral variability. High resolution spectra obtained by the XMM-Newton RGS detector reveal that the wind consists of three distinct ionization components, all outflowing at a velocity of 5000 km/s. This wind is clearly revealed when the source is observed at an intermediate flux state (2-5e-12 ergs cm^-2 s^-1). The analysis of multi-epoch RGS spectra allowed us to compare the absorber properties at three very different flux states of the source. No correlation between the warm absorber variability and the X-ray flux has been determined. The two higher ionization components of the gas may be consistent with photoionization equilibrium, but we can exclude this for the only ionization component that is consistently present in all flux states (log(xi)~1.8). We have included archival, non-simultaneous UV data from HST (FOS, STIS, COS) with the aim of searching for any signature of absorption in this source that so far was known for being absorption-free in the UV band. In the COS spectra obtained a few months after the X-ray observations we found broad absorption in CIV lines intrinsic to the AGN and blueshifted by a velocity roughly comparable to the X-ray outflow. The global behavior of the gas in both bands can be explained by variation of the covering factor and/or column density, possibly due to transverse motion of absorbing clouds moving out of the line of sight at Broad Line Region scale.Comment: 24 pages, 12 figures, ApJ accepte

    A Complete Sample of Soft X-ray Selected AGN: I. The Data

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    We present the optical spectra and simple statistical analysis for a complete sample of 110 soft X-ray selected AGN. About half of the sources are Narrow-Line Seyfert 1 galaxies (NLS1s), which have the steepest X-ray spectra, strongest FeII emission and slightly weaker [OIII]5007 emission than broad line Seyfert 1s (BLS1s). Kolmogorov Smirnov tests show that NLS1s and BLS1s have clearly different distributions of the X-ray spectral slope, X-ray short-term variability, and FeII equivalent widths and luminosity and FeII/H-beta ratios. The differences in the [OIII]/H-beta and [OIII] equivalent widths are only marginal. We found no significant differences between NLS1s and BLS1s in their rest frame 0.2-2.0 X-ray luminosities, rest frame 5100A monochromatic luminosities, bolometric luminosities, redshifts, and their Hβ\beta equivalent widths.Comment: Accepted for publication in AJ (scheduled for January 2004), 21 pages, 10 figures, The paper including the optical spectra and FeII subtracted spectra can be retrieved from http://www.astronomy.ohio-state.edu/~dgrupe/research/sample_paper1.htm

    HST STIS Ultraviolet Spectral Evidence for Outflow in Extreme Narrow-line Seyfert 1 Galaxies: I. Data and Analysis

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    We present HST STIS observations of two extreme NLS1s, IRAS 13224-3809 and 1H 0707-495. The spectra are characterized by very blue continua, broad, strongly blueshifted high-ionization lines (including \ion{C}{4} and \ion{N}{5}), and narrow, symmetric intermediate- (including \ion{C}{3}], \ion{Si}{3}], \ion{Al}{3}) and low-ionization (e.g., \ion{Mg}{2}) lines centered at their rest wavelengths. The emission-line profiles suggest that the high-ionization lines are produced in a wind, and the intermediate- and low-ionization lines are produced in low-velocity gas associated with the accretion disk or base of the wind. In this paper, we present the analysis of the spectra from these two objects; in a companion paper we present photoionization analysis and a toy dynamical model for the wind. The highly asymmetric profile of \ion{C}{4} suggests that it is dominated by emission from the wind, so we develop a template for the wind from the \ion{C}{4} line. We model the bright emission lines in the spectra using a combination of this template, and a narrow, symmetric line centered at the rest wavelength. We also analyzed a comparison sample of HST spectra from 14 additional NLS1s, and construct a correlation matrix of emission line and continuum properties. A number of strong correlations were observed, including several involving the asymmetry of the \ion{C}{4} line.Comment: 26 pages, 10 figures, accepted for publication in ApJ with no change
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