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Register a new userThe nuclear environment of the NLS1 Mrk 335: obscuration of the X-ray line emission by a variable outflow
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We present XMM-Newton, NuSTAR, Swift and Hubble Space Telescope observations of the Narrow-line Seyfert 1 galaxy Mrk 335 in a protracted low state in 2018 and 2019. The X-ray flux is at the lowest level so far observed, and the extremely low continuum flux reveals a host of soft X-ray emission lines from photoionised gas. The simultaneous UV flux drop suggests that the variability is intrinsic to the source, and we confirm this with broad-band X-ray spectroscopy. The dominance of the soft X-ray lines at low energies and distant reflection at high energies is therefore due to the respective emission regions being located far enough from the X-ray source that they have not yet seen the flux drop. Between the two XMM-Newton spectra, taken 6 months apart, the emission line ratio in the Ovii triplet changes drastically. We attribute this change to a drop in the ionisation of intervening warm absorption, which means that the absorber must cover a large fraction of the line emitting region, and extend much further from the black hole than previously assumed. The HST spectrum, taken in 2018, shows that new absorption features have appeared on the blue wings of Ciii*, Ly{alpha}, Nv, Siiv and Civ, likely due to absorbing gas cooling in response to the low flux state.
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We present an analysis of all the archival high resolution spectra of the Narrow-line Seyfert 1 galaxy Mrk~335 obtained with Reflection Grating Spectrometer (RGS) on board textit{XMM-Newton}. The spectra show rich emission and absorption features in low and intermediate flux intervals. We model the emission lines with the textsc{pion_xs} grid and try to find any possible correlation between the properties of the emitting gas and the source flux. Current data does not allow detailed trace of the response of the line emitting gas to the X-ray flux of Mrk~335, but the flux of the X-ray lines is significantly less variable than the X-ray continuum. We also find that the warm absorbers properties are not correlated with the flux variability. From the latest textit{XMM-Newton} observation in 2019 December, we find that the photoionized emission and distant reflection components have not responded to the flux drop of Mrk~335 from 2018 July. However, the possible existence of partial covering absorber in the 2018--2019 low state of Mrk~335 makes it difficult to constrain the scale of the emitting gas using this lack of response.
X-ray observations of the unique NLS1 galaxy Mrk 1239 spanning 18-years are presented. Data from XMM-Newton, Suzaku, Swift and NuSTAR are combined to obtain a broad-band, multi-epoch view of the source. There is spectral variability in the 3-10 keV band over the 18-years. An analysis of the NuSTAR and Suzaku light curves also suggests rapid variability in the 3-10 keV band, which is consistent with the NLS1 definition of the source. However, no variability is seen below 3 keV on any timescale. Two distinct physical models are adopted to describe the data above and below ~3 keV. The low energies are dominated by a hot, diffuse gas likely associated with a starburst component at large physical scales. The higher energy spectrum is dominated by emission from the central region. Ionised partial covering and relativistic blurred reflection are considered for the central region emission. In both cases, the underlying power law has a photon index of $Gammasim2.3-2.4$. A distant reflector, a neutral partial covering component with a covering fraction near $sim1$, and contributions from starburst emission are always required. The blurred reflection model requires a reflection dominated spectrum, which may be at odds with the low emissivity index and radio properties of the source. By contrast, the two absorption components required in the ionised partial covering model may correspond to the two distinct regions of polarization observed in the optical. Regardless of the physical model, spectral changes between epochs are driven by the absorption components and on short time scales by intrinsic AGN variability.
A triggered 140 ks XMM-Newton observation of the narrow-line Seyfert 1 (NLS1) Mrk 335 in December 2015 caught the active galaxy at its lowest X-ray flux since 2007. The NLS1 is relatively quiescent for the first ~120 ks of the observation before it flares in brightness by a factor of about five in the last 20 ks. Although only part of the flare is captured before the observation is terminated, the data reveal significant differences between the flare and quiescent phases. During the low-flux state, Mrk 335 demonstrates a reflection-dominated spectrum that results from a compact corona around a Kerr black hole. In addition to the rapid brightening, the flare is further described by spectral softening and a falling reflection fraction that are consistent with previous observations advocating at least part of the corona in Mrk 335 could be the base of an aborted jet. The spectrum during the flaring interval reveals several residuals between the 2-3 sigma level that could be attributed to absorption lines from a highly ionised plasma that is moving outward at v~0.12c. It could be that the increased luminosity during the flare enhances the radiation pressure sufficiently to launch a possible wind. If the wind is indeed responding to the change in corona luminosity then it must be located within ~80 Rg. The escape velocity at this distance is comparable to the estimated wind velocity. If confirmed, this is the first example of a radio-quiet AGN exhibiting behaviour consistent with both diffuse and collimated outflow.
The Seyfert Galaxy Mrk 335 is known for its frequent changes of flux and spectral shape in the X-ray band occurred during recent years. These variations may be explained by the onset of a wind that previous, non-contemporaneous high-resolution spectroscopy in X-ray and UV bands located at accretion disc scale. A simultaneous new campaign by XMM-Newton and HST caught the source at an historical low flux in the X-ray band. The soft X-ray spectrum is dominated by prominent emission features, and by the effect of a strong ionized absorber with an outflow velocity of 5-6X10$^3$~km~s$^{-1}$. The broadband spectrum obtained by the EPIC-pn camera reveals the presence of an additional layer of absorption by gas at moderate ionization covering 80% of the central source, and tantalizing evidence for absorption in the Fe~K band outflowing at the same velocity of the soft X-ray absorber. The HST-COS spectra confirm the simultaneous presence of broad absorption troughs in CIV, Ly alpha, Ly beta and OVI, with velocities of the order of 5000 km~s$^{-1}$ and covering factors in the range of 20-30%. Comparison of the ionic column densities and of other outflow parameters in the two bands show that the X-ray and UV absorbers are likely originated by the same gas. The resulting picture from this latest multi-wavelength campaign confirms that Mrk 335 undergoes the effect of a patchy, medium-velocity outflowing gas in a wide range of ionization states that seem to be persistently obscuring the nuclear continuum.
We present a broadband (~0.5-79 keV) spectral and temporal analysis of multiple NuSTAR observations combined with archival Suzaku and Chandra data of NGC4945, the brightest extragalactic source at 100 keV. We observe hard X-ray (> 10 keV) flux and spectral variability, with flux variations of a factor 2 on timescales of 20 ksec. A variable primary continuum dominates the high energy spectrum (>10 keV) in all the states, while the reflected/scattered flux which dominates at E< 10 keV stays approximately constant. From modelling the complex reflection/transmission spectrum we derive a Compton depth along the line of sight of tau_Thomson ~ 2.9, and a global covering factor for the circumnuclear gas of ~ 0.15. This agrees with the constraints derived from the high energy variability, which implies that most of the high energy flux is transmitted, rather that Compton-scattered. This demonstrates the effectiveness of spectral analysis in constraining the geometric properties of the circumnuclear gas, and validates similar methods used for analyzing the spectra of other bright, Compton-thick AGN. The lower limits on the e-folding energy are between 200-300 keV, consistent with previous BeppoSAX, Suzaku and Swift BAT observations. The accretion rate, estimated from the X-ray luminosity and assuming a bolometric correction typical of type 2 AGN, is in the range ~0.1-0.3 lambda_Edd depending on the flux state. The substantial observed X-ray luminosity variability of NGC4945 implies that large errors can arise from using single-epoch X-ray data to derive L/L_Edd values for obscured AGNs.
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