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Register a new userMultiwavelength studies of the Seyfert 1 galaxy NGC7469. I - Far UV observations with FUSE
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G. A. Kriss
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We obtained far-ultraviolet spectra of the Seyfert 1 galaxy NGC 7469 using the FUSE on 1999 December 6. Our spectra cover the wavelength range 990-1187 A with a resolution of 0.05 A. We see broad emission lines of CIII, NIII, OVI, and HeII as well as intrinsic absorption lines in the OVI 1032,1038 resonance doublet. The absorption arises in two distinct kinematic components at systemic velocities of -569 km/s and -1898 km/s. Both components are very highly ionized- no significant Ly beta absorption is present. The higher blueshift component is not quite saturated, and it has a total OVI column density of 8e14/cm2. It covers more than 90% of the continuum and broad-line emission. The lower blue shift component is heavily saturated and covers only 50% of the continuum and broad-line emission. It too has a column density of 8e14/cm2, but this is less certain due to the high saturation. We set an upper limit of <1.5e18/cm2 on the OVI column density of this component. Its line depth is consistent with coverage of only the continuum, and thus this component may lie interior to the broad emission-line gas. The component at -569 km/s has a velocity comparable to the high-ionization X-ray absorption lines seen in the XMM-Newton grating spectrum of NGC 7469, and photoionization models show that the observed column densities of OVI and HI are compatible with their formation in the same gas as that causing the X-ray absorption. The gas at -1898 km/s has lower ionization and column density, and no significant X-ray absorption is associated with it.
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We present an XMM-Newton observation of NGC 7469, including studies of the X-ray and UV variability, 0.2-10 keV spectral continuum, Fe K-alpha emission line and the first-ever high-resolution X-ray spectrum of the soft X-ray warm absorber. We compare the properties of this X-ray warm absorber with the UV warm absorber as seen in a FUSE observation one year previously. The 0.2-10 keV spectral continuum is best fitted by a power-law plus two blackbody model. An Fe K-alpha emission line is visible which consists of a single narrow component and is well-modelled by a simple gaussian. Narrow absorption and emission lines in the soft X-ray RGS spectrum demonstrate the existence of a multi-phase warm absorber with a range in log xi of ~ 2 to ~ -2 where xi is in erg cm s^-1. The warm absorber is blueshifted by several hundred km s^-1. The highest-ionisation phase of the absorber is the best constrained and has an overall equivalent Hydrogen column of order 10^20 cm^-2; we find that its ionisation parameter is consistent with that of the warm emitter which generates the narrow emission lines. We identify this high ionisation absorber with the low-velocity phase of the UV absorber observed by FUSE.
We present far-ultraviolet spectra of the Seyfert 1 galaxy Mrk 509 obtained in 1999 November with the Far Ultraviolet Spectroscopic Explorer (FUSE). Our data span the observed wavelength range 915-1185 A at a resolution of ~20 km/s. The spectrum shows a blue continuum, broad OVI 1032,1038 emission, and a broad CIII 977 emission line. Superposed on these emission components, we resolve associated absorption lines of OVI 1032,1038, CIII 977, and Lyman lines through Lzeta. Seven distinct kinematic components are present, spanning a velocity range of -440 to +170 km/s relative to the systemic velocity. The absorption is clustered in two groups, one centered at -370m km/s and another at the systemic velocity. The blue-shifted cluster may be associated with the extended line emission visible in deep images of Mrk 509 obtained by Phillips et al. Although several components appear to be saturated, they are not black at their centers. Partial covering or scattering permits ~7% of the broad-line or continuum flux to be unaffected by absorption. Of the multiple components, only one has the same ionization state and column density as highly ionized gas that produces the OVII and OVIII ionization edges in X-ray spectra of Mrk 509. This paper will appear in a special issue of Astrophysical Journal Letters devoted to the first scientific results from the FUSE mission.
ACO 3627 is a rich, nearby cluster of galaxies at the core of the Great Attractor. At the low galactic latitude of b = -7.2 the galactic extinction is significant. Nevertheless, its proximity makes it a prime target for studies of environmental effects on its cluster members. Here, we report on a multi-wavelength study of a Seyfert 1 galaxy at 30 arcminutes from the centre of ACO 3627. Its Seyfert nature was discovered spectroscopically and confirmed in X-rays. We have obtained B_J and R_C CCD photometry as well as J, H, K and L aperture photometry at the SAAO, low and high resolution spectroscopy (ESO and SAAO), 21 cm line observations (Parkes Observatory) and X-ray ROSAT PSPC data. The Seyfert 1 galaxy is of morphology SBa(r). It has a nearby companion (dS0) but shows no signs of interaction. A consistent value for the galactic extinction of A_B = 1.6 mag could be determined. The nucleus of the Seyfert is very blue with a strong (B_J - R_C) colour gradient in the inner 2.5 arcsec. The extinction-corrected near-infrared colours of WKK 6092 are typical of a Seyfert 1 and the X-ray spectrum conforms to the expectation of a Seyfert as well. The galaxy has a very low HI flux. This could be explained by its morphology, but also -- due to its very central position within the rich Norma cluster -- to ram pressure stripping.
We present the results of a two-year long optical monitoring program of the narrow-line Seyfert 1 galaxy Akn 564. The majority of this monitoring project was also covered by X-ray observations (RXTE) and for a period of ~50 days, we observed the galaxy in UV (HST) and X-rays (RXTE & ASCA) simultaneously with the ground-based observations. Rapid and large-amplitude variations seen in the X-ray band, on a daily and hourly time-scale, were not detected at optical and UV wavelengths, which in turn exhibited much lower variability either on short (one day) or long (several months) time-scales. The only significant optical variations can be described as two 2--4 day events with ~10% flux variations. We detect no significant optical line variations and thus cannot infer a reverberation size for the broad-line region. Similarly, the large X-ray variations seem to vanish when the light curve is smoothed over a period of 30 days. The UV continuum follows the X-rays with a lag of ~0.4 days, and the optical band lags the UV band by ~2 days. No significant correlation was found between the entire X-ray dataset and the optical band. Focusing on a 20-day interval around the strongest optical event we detect a significant X-ray--optical correlation with similar events seen in the UV and X-rays. Our data are consistent with reprocessing models on the grounds of the energy emitted in this single event. However, several large X-ray flares produced no corresponding optical emission.
We present a supermassive black hole (SMBH) mass measurement in the Seyfert 1 galaxy NGC7469 using Atacama Large Millimeter/submillimeter Array (ALMA) observations of the atomic-${rm [CI]}$(1-0) and molecular-$^{12}$CO(1-0) emission lines at the spatial resolution of $approx0.3$ (or $approx$ 100 pc). These emissions reveal that NGC7469 hosts a circumnuclear gas disc (CND) with a ring-like structure and a two-arm/bi-symmetric spiral pattern within it, surrounded by a starbursting ring. The CND has a relatively low $sigma/Vapprox0.35$ ($rsim0.5$) and $sim0.19$ ($r>0.5$), suggesting that the gas is dynamically settled and suitable for dynamically deriving the mass of its central source. As is expected from X-ray dominated region (XDR) effects that dramatically increase an atomic carbon abundance by dissociating CO molecules, we suggest that the atomic [CI](1-0) emission is a better probe of SMBH masses than CO emission in AGNs. Our dynamical model using the ${rm [CI]}$(1-0) kinematics yields a $M_{rm BH}=1.78^{+2.69}_{-1.10}times10^7$M$_odot$ and $M/L_{rm F547M}=2.25^{+0.40}_{-0.43}$ (M$_odot$/L$_odot$). The model using the CO(1-0) kinematics also gives a consistent $M_{rm BH}$ with a larger uncertainty, up to an order of magnitude, i.e. $M_{rm BH}=1.60^{+11.52}_{-1.45}times10^7$M$_odot$. This newly dynamical $M_{rm BH}$ is $approx$ 2 times higher than the mass determined from the reverberation mapped (RM) method using emissions arising in the unresolved broad-line region (BLR). Given this new $M_{rm BH}$, we are able to constrain the specific RM dimensionless scaling factor of $f=7.2^{+4.2}_{-3.4}$ for the AGN BLR in NGC7469. The gas within the unresolved BLR thus has a Keplerian virial velocity component and the inclination of $iapprox11.0^circ$$_{-2.5}^{+2.2}$, confirming its face-on orientation in a Seyfert 1 AGN by assuming a geometrically thin BLR model.
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