Anatomy of the AGN in NGC 5548

Arav, Nahum; Chamberlain, Carter; Kriss, G. A.; Kaastra, J. S.; Cappi, M.; Mehdipour, M.; Petrucci, Pierre-Olivier; Steenbrugge, K. C.; Behar, E.; Bianchi, S.; Boissay, R.; Branduardi‐Raymont, G.; Costantini, E.; Ely, Justin; Ebrero, J.; Gesu, Laura Di; Harrison, Fiona A.; Kaspi, S.; Malzac, J.; Marco, Barbara De; Matt, Giorgio; Nandra, K.; Paltani, S.; Peterson, B. M.; Pinto, C.; Ponti, G.; Núñez, F. Pozo; Rosa, A. De; Seta, Hiromi; Ursini, F.; Vries, C. P. de; Walton, D. J.; Whewell, M.

doi:10.1051/0004-6361/201425302

Cited by 97 publications

(121 citation statements)

References 44 publications

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“…Indeed, in this obscured condition, the historical NGC 5548 WA is still present, but with a lower ionization. In the X-rays, the WA is consistent with being ∼3 times less ionized than what was observed in 2002 (K14), and, at the same time, in the UV it shows new lower-ionization NAL (from, e.g., C  and C , Arav et al 2015).…”

Section: Introductionsupporting

confidence: 81%

“…Thus, our analysis confirms the K14 finding. The decrease in the WA ionization, which is also seen in the UV (Arav et al 2015) is explained when the newly discovered obscurer is located between the nucleus and the WA. In this geometry, the obscurer shadows the central source and prevents most of the ionizing flux from reaching the warm absorber.…”

Section: The Short-term Variabilitymentioning

confidence: 86%

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Anatomy of the AGN in NGC 5548

Gesu

Costantini

Ebrero

et al. 2015

A&A

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During an extensive multiwavelength campaign that we performed in 2013−2014, we found the prototypical Seyfert 1 galaxy NGC 5548 in an unusual condition of heavy and persistent obscuration. The newly discovered "obscurer" absorbs most of the soft X-ray continuum along our line of sight and lowers the ionizing luminosity received by the classical warm absorber. We present the analysis of the high resolution X-ray spectra collected with XMM-Newton and Chandra throughout the campaign, which are suitable to investigate the variability of both the obscurer and classical warm absorber. The time separation between these X-ray observations range from two days to eight months. On these timescales the obscurer is variable both in column density and in covering fraction. This is consistent with the picture of a patchy wind. The most significant variation occurred in September 2013 when the source brightened for two weeks. A higher and steeper intrinsic continuum and a lower obscurer covering fraction are both required to explain the spectral shape during the flare. We suggest that a geometrical change of the soft X-ray source behind the obscurer causes the observed drop in the covering fraction. Because of the higher soft X-ray continuum level, the September 2013 Chandra spectrum is the only X ray spectrum of the campaign in which individual features of the warm absorber could be detected. The spectrum shows absorption from Fe-UTA, O , and O , consistent with belonging to the lower-ionization counterpart of the historical NGC 5548 warm absorber.Hence, we confirm that the warm absorber has responded to the drop in the ionizing luminosity caused by the obscurer.

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Section: Introductionsupporting

confidence: 81%

Section: The Short-term Variabilitymentioning

confidence: 86%

Anatomy of the AGN in NGC 5548

Gesu

Costantini

Ebrero

et al. 2015

A&A

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“…There are of course more transitions than we listed in Table 2. For instance, there are in total six 1s 2 2s2p ( 3 P)-1s 2 2p 2 ( 3 P) metastable transitions around λ ∼ 1175 Å for C iii that have been successfully used for density diagnostics in AGN ionized outflows (e.g., Arav et al 2015). Transitions with higher f -values are listed in Table 2 for simplicity.…”

Section: Resultsmentioning

confidence: 99%

“…As such, it exhibits all the typical spectral features seen in type 1 Seyfert galaxies. The broadband (from optical to hard X-ray) spectral energy distribution (SED) and various properties from the multiphase ionized outflow are well studied (e.g., Kaastra et al 2014;Mehdipour et al 2015b;Arav et al 2015;Ebrero et al 2016). NGC 5548 was observed with Chandra in January 2002 with both high-and low-energy transmission grating spectrometers (HETGS and LETGS), which allow us to study the X-ray absorption features in a wide wavelength range (∼2−60 Å).…”

Section: Density Diagnostics For the Ionized Outflow In Ngc 5548mentioning

confidence: 99%

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Density diagnostics of ionized outflows in active galactic nuclei

Mao

Kaastra

Mehdipour

et al. 2017

A&A

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Context. Ionized outflows in active galactic nuclei (AGNs) are thought to influence their nuclear and local galactic environment. However, the distance of the outflows with respect to the central engine is poorly constrained, which limits our understanding of their kinetic power as a cosmic feedback channel. Therefore, the impact of AGN outflows on their host galaxies is uncertain. However, when the density of the outflows is known, their distance can be immediately obtained from their modeled ionization parameters. Aims. We perform a theoretical study of density diagnostics of ionized outflows using absorption lines from metastable levels in Be-like to C-like cosmic abundant ions. Methods. With the new self-consistent PhotoIONization (PION) model in the SPEX code, we are able to calculate detailed level populations, including the ground and metastable levels. This enables us to determine under what physical conditions the metastable levels are significantly populated. We then identify characteristic lines from these metastable levels in the 1−2000 Å wavelength range. Results. In the broad density range of n H ∈ (10 6 , 10 20 ) m −3 , the metastable levels 2s2p ( 3 P 0−2 ) in Be-like ions can be significantly populated. For B-like ions, merely the first excited level 2s 2 2p ( 2 P 3/2 ) can be used as a density probe. For C-like ions, the first two excited levels 2s 2 2p 2 ( 3 P 1 and 3 P 2 ) are better density probes than the next two excited levels 2s 2 2p 2 ( 1 S 0 and 1 D 2 ). Different ions in the same isoelectronic sequence cover not only a wide range of ionization parameters, but also a wide range of density values. On the other hand, within the same isonuclear sequence, those less ionized ions probe lower density and smaller ionization parameters. Finally, we reanalyzed the high-resolution grating spectra of NGC 5548 observed with Chandra in January 2002 using a set of PION components to account for the ionized outflow. We derive lower (or upper) limits of plasma density in five out of six PION components based on the presence (or absence) of the metastable absorption lines. Once atomic data from N-like to F-like ions are available, combined with the next generation of spectrometers that cover both X-ray and UV wavelength ranges with higher spectral resolution and larger effective areas, tight constraints on the density and thus the location and kinetic power of AGN outflows can be obtained.

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High‐energy monitoring of Seyfert galaxies: The case of NGC 4593

et al. 2016

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We discuss preliminary results from a joint XMM-Newton and NuSTAR monitoring program on the active galactic nucleus NGC 4593, consisting of 5 × 20 ks observations, spaced by two days, performed in January 2015. The source is found to be variable, both in flux and spectral shape, on time scales as short as a few ks. The spectrum clearly softens when the source brightens. A simple timing analysis suggests the presence of a variable soft excess that correlates with the primary continuum.

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Anatomy of the AGN in NGC 5548

Cited by 97 publications

References 44 publications

Anatomy of the AGN in NGC 5548

Anatomy of the AGN in NGC 5548

Density diagnostics of ionized outflows in active galactic nuclei

High‐energy monitoring of Seyfert galaxies: The case of NGC 4593

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