Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert galaxies - I. A global view and frequency of occurrence of warm absorbers.

Laha, Sibasish; Guainazzi, M.; Dewangan, G. C.; Chakravorty, Susmita; Kembhavi, Ajit

doi:10.1093/mnras/stu669

Cited by 147 publications

(194 citation statements)

References 101 publications

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“…6, and resembles the AMD of Blustin et al (2007). This is also well in agreement with the usual bi-modal shape commonly observed in AGNs (Behar 2009;Laha et al 2014). The consistency of the AMD structure along with the individual ionic column measurements increases our confidence that the absorber is unchanged between the 2004 and 2015 observations.…”

Section: Absorption Measure Distributionsupporting

confidence: 85%

Multi-wavelength campaign on NGC 7469

Peretz

Behar

Kriss

et al. 2018

A&A

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We investigate the ionic column density variability of the ionized outflows associated with NGC 7469, to estimate their location and power. This could allow a better understanding of galactic feedback of AGNs to their host galaxies. Analysis of seven XMM-Newton grating observations from 2015 is reported. We use an individual-ion spectral fitting approach, and compare different epochs to accurately determine variability on time-scales of years, months, and days. We find no significant column density variability in a 10 year period implying that the outflow is far from the ionizing source. The implied lower bound on the ionization equilibrium time, 10 years, constrains the lower limit on the distance to be at least 12 pc, and up to 31 pc, much less but consistent with the 1 kpc wide starburst ring. The ionization distribution of column density is reconstructed from measured column densities, nicely matching results of two 2004 observations, with one large high ionization parameter (ξ) component at 2 < log ξ < 3.5, and one at 0.5 < log ξ < 1 in cgs units. The strong dependence of the expression for kinetic power, ∝ 1/ξ, hampers tight constraints on the feedback mechanism of outflows with a large range in ionization parameter, which is often observed and indicates a non-conical outflow. The kinetic power of the outflow is estimated here to be within 0.4 and 60 % of the Eddington luminosity, depending on the ion used to estimate ξ.

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Section: Absorption Measure Distributionsupporting

confidence: 85%

Multi-wavelength campaign on NGC 7469

Peretz

Behar

Kriss

et al. 2018

A&A

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“…Indeed the velocities of most X-ray warm absorber components typically fall in the range from 0 up to −2000 km s −1 (Blustin et al 2005;McKernan et al 2007;Laha et al 2014), while the UV velocity components can also cover a similar range of velocity as seen in X-rays . Typical outflow velocities of a few hundred km s −1 are also seen for the soft X-ray absorber in many well studied cases; e.g.…”

Section: Main Observational Resultsmentioning

confidence: 97%

High-resolution X-Ray Spectroscopy of the Seyfert 1 Galaxy Mrk 1040. Revealing the Failed Nuclear Wind with Chandra

Reeves

Braito

Behar

et al. 2017

ApJ

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High resolution X-ray spectroscopy of the warm absorber in the nearby X-ray bright Seyfert 1 galaxy, Mrk 1040 is presented. The observations were carried out in the 2013-2014 timeframe using the Chandra High Energy Transmission Grating with a total exposure of 200 ks. A multitude of absorption lines from Ne, Mg and Si are detected from a wide variety of ionization states. In particular, the detection of inner K-shell absorption lines from Ne, Mg and Si, from charge states ranging from F-like to Li-like ions, suggests the presence of a substantial amount of low ionization absorbing gas, illuminated by a steep soft X-ray continuum. The observations reveal at least 3 warm absorbing components ranging in ionization parameter from log(ξ/erg cm s −1 ) = 0 − 2 and with column densities of N H = 1.5 − 4.0 × 10 21 cm −2 . The velocity profiles imply that the outflow velocities of the absorbing gas are low and within ±100 km s −1 of the systemic velocity of Mrk 1040, which suggests any outflowing gas may have stalled in this AGN on large enough scales. The warm absorber is likely located far from the black hole, within 300 pc of the nucleus and is spatially coincident with emission from an extended Narrow Line Region as seen in the HST images. The iron K band spectrum reveals only narrow emission lines, with Fe Kα at 6.4 keV consistent with originating from reflection off Compton thick pc-scale reprocessing gas.

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“…(2) WAs are seen in more than half of all quasars (Piconcelli et al 2005, Laha et al 2014) and a cool (~10 4 K) low ionization phase (LIP) in pressure equilibrium with the warmer (~10 5 K -10 6 K) phase is also normal 3 .…”

Section: Observationalmentioning

confidence: 99%

Quasar Rain: The Broad Emission Line Region as Condensations in the Warm Accretion Disk Wind

Elvis

2017

ApJ

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The origin of the broad emission line region (BELR) in quasars and active galactic nuclei is still unclear. I propose that condensations form in the warm, radiation pressure driven, accretion disk wind of quasars creating the BEL clouds and uniting them with the other two manifestations of cool (~10 4 K) gas in quasars, the low ionization phase of the warm absorbers (WAs) and the clouds causing X-ray eclipses. The cool clouds will condense quickly (days -years), before the WA outflows reach escape velocity (which takes months -centuries). Cool clouds form in equilibrium with the warm phase of the wind because the rapidly varying X-ray quasar continuum changes the force multiplier, causing pressure waves to move gas into stable locations in pressure-temperature space. The narrow range of 2-phase equilibrium densities may explain the (luminosity) 1/2 scaling of the BELR size, while the scaling of cloud formation timescales could produce the Baldwin effect. These dense clouds have force multipliers of order unity and so cannot be accelerated to escape velocity. They fall back on a dynamical timescale (monthscenturies), producing an inflow that rains down toward the central black hole. As they soon move at Mach ~10 -100 with respect to the WA outflow, these "raindrops" will be rapidly destroyed within months. This rain of clouds may produce the elliptical BELR orbits implied by velocity resolved reverberation mapping in some objects, and can explain the opening angle and destruction timescale of the narrow "cometary" tails of the clouds seen in X-ray eclipse observations. Some consequences and challenges of this "quasar rain" model are presented along with several avenues for theoretical investigation.

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Warm absorbers in X-rays (WAX), a comprehensive high-resolution grating spectral study of a sample of Seyfert galaxies - I. A global view and frequency of occurrence of warm absorbers.

Cited by 147 publications

References 101 publications

Multi-wavelength campaign on NGC 7469

Multi-wavelength campaign on NGC 7469

High-resolution X-Ray Spectroscopy of the Seyfert 1 Galaxy Mrk 1040. Revealing the Failed Nuclear Wind with Chandra

Quasar Rain: The Broad Emission Line Region as Condensations in the Warm Accretion Disk Wind

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