An XMM–Newton observation of Mkn 3 – a Seyfert galaxy just over the edge

A 100-ks XMM–Newton observation of the nearby Seyfert 2 galaxy Mkn 3 offers a unique opportunity to explore the complexity of its X-ray spectrum. We find the  ∼3–8 keV  continuum to be dominated by reflection from cold matter, with fluorescent K-shell lines detected from Ni, Fe, Ca, Ar, S, Si and Mg. At higher energies an intrinsic power-law continuum, with canonical Seyfert 1 photon index, is seen through a near-Compton-thick cold absorber. A soft excess below ∼3 keV is found to be dominated by line emission from an outflow of 'warm' gas, photoionized and photoexcited by the intrinsically strong X-ray continuum. Measured blueshifts in the strong Fe Kα and O  vii and O  viii emission lines are discussed in terms of the properties of the putative molecular torus and ionized outflow.     

XMM–Newton and Suzaku analysis of the Fe K complex in the type 1 Seyfert galaxy Mrk 509

We report on partially overlapping XMM–Newton (∼260 ks) and Suzaku (∼100 ks) observations of the iron K band in the nearby, bright type 1 Seyfert galaxy Mrk 509. The source shows a resolved neutral Fe K line, most probably produced in the outer part of the accretion disc. Moreover, the source shows further emission bluewards of the 6.4 keV line due to ionized material. This emission is well reproduced by a broad line produced in the accretion disc, while it cannot be easily described by scattering or emission from photoionized gas at rest. The summed spectrum of all XMM–Newton observations shows the presence of a narrow absorption line at 7.3 keV produced by highly ionized outflowing material. A spectral variability study of the XMM–Newton data shows an indication for an excess of variability at 6.6–6.7 keV. These variations may be produced in the red wing of the broad ionized line or by variation of a further absorption structure. The Suzaku data indicate that the neutral Fe K α line intensity is consistent with being constant on long time-scales (of a few years), and they also confirm as most likely the interpretation of the excess blueshifted emission in terms of a broad ionized Fe line. The average Suzaku spectrum differs from the XMM–Newton one in the disappearance of the 7.3 keV absorption line and around 6.7 keV, where the XMM–Newton data alone suggested variability.     

XMM–Newton observations of the Seyfert 1 AGN H 0557−385

We present XMM–Newton observations of the Seyfert 1 active galactic nucleus (AGN)  H 0557 − 385  . We have conducted a study into the warm absorber present in this source, and using high-resolution Reflection Grating Spectrometer (RGS) data we find that the absorption can be characterized by two phases: a phase with log ionization parameter ξ of 0.50 (where ξ is in units of erg cm s⁻¹) and a column of  0.2 × 10²¹ cm⁻²  , and a phase with log ξ of 1.62 and a column of  1.3 × 10²² cm⁻²  . An iron Kα line is detected. Neutral absorption is also present in the source, and we discuss possible origins for this. On the assumption that the ionized absorbers originate as an outflow from the inner edge of the torus, we use a new method for finding the volume filling factor. Both phases of  H 0557 − 385  have small volume filling factors (≤1 per cent). We also derive the volume filling factors for a sample of 23 AGN using this assumption and for the absorbers with  log ξ > 0.7  , we find reasonable agreement with the filling factors obtained through the alternative method of equating the momentum flow of the absorbers to the momentum loss of the radiation field. By comparing the filling factors obtained by the two methods, we infer that some absorbers with  log ξ < 0.7  occur at significantly larger distances from the nucleus than the inner edge of the torus.     

An XMM–Newton observation of the galaxy group MKW 4

We present an X-ray study of the galaxy group or poor cluster MKW 4. Working with XMM–Newton data we examine the distribution and properties of the hot gas which makes up the group halo. The inner halo shows some signs of structure, with circular or elliptical beta models providing a poor fit to the surface brightness profile. This may be evidence of large-scale motion in the inner halo, but we do not find evidence of sharp fronts or edges in the emission. The temperature of the halo declines in the core, with deprojected spectral fits showing a central temperature of ∼1.3 keV compared to ∼3 keV at 100 kpc. In the central ∼30 kpc of the group, multitemperature spectral models are required to fit the data, but they indicate a lack of gas at low temperatures. Steady-state cooling flow models provide poor fits to the inner regions of the group and the estimated cooling time of the gas is long except within the central dominant galaxy, NGC 4073. Abundance profiles show a sharp increase in the core of the group, with mean abundance rising by a factor of 2 in the centre of NGC 4073. Fitting individual elements shows the same trend, with high values of Fe, Si and S in the core. We estimate that ∼50 per cent of the Fe in the central 40 kpc was injected by Type Ia supernovae, in agreement with previous ASCA studies. Using our best-fitting surface brightness and temperature models, we calculate the mass, gas fraction, entropy and mass-to-light ratio of the group. At 100 kpc (∼0.1 virial radius) the total mass and gas entropy of the system (  ∼2 × 10¹³ M_⊙  and ∼300 keV cm²) are quite comparable to those of other systems of similar temperature, but the gas fraction is rather low (∼1 per cent). We conclude that MKW 4 is a fairly relaxed group, which has developed a strong central temperature gradient but not a large-scale cooling flow.     

An XMM–Newton observation of Abell 2597

We report on a 120-ks XMM–Newton observation of the galaxy cluster Abell 2597 (A2597). Results from both the European Photon Imaging Camera (EPIC) and the Reflection Grating Spectrometer (RGS) are presented. From EPIC we obtain radial profiles of temperature, density and abundance, and use these to derive cooling time and entropy. We illustrate corrections to these profiles for projection and point spread function (PSF) effects. At the spatial resolution available to XMM–Newton , the temperature declines by around a factor of 2 in the central 150 kpc or so in radius, and the abundance increases from about one-fifth to over one-half solar. The cooling time is less than 10 Gyr inside a radius of 130 kpc. EPIC fits to the central region are consistent with a cooling flow of around 100 solar masses per year. Broad-band fits to the RGS spectra extracted from the central 2 arcmin are also consistent with a cooling flow of the same magnitude; with a preferred low-temperature cut-off of essentially zero. The data appear to suggest (albeit at low significance levels below formal detection limits) the presence of the important thermometer lines from Fe  xvii at 15–17 Å rest wavelength, characteristic of gas at temperatures ∼0.3 keV. The measured flux in each line is converted to a mass-deposition estimate by comparison with a classical cooling flow model, and once again values at the level of 100 solar masses per year are obtained. These mass-deposition rates, whilst lower than those of previous generations of X-ray observatories, are consistent with those obtained from ultraviolet data for this object. This raises the possibility of a classical cooling flow, at the level of around 100 solar masses per year, cooling from 4 keV by more than two orders of magnitude in temperature.