2009A&A...496..107S


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.05CET21:38:52

2009A&A...496..107S - Astronomy and Astrophysics, volume 496, 107-119 (2009/3-2)

High-resolution X-ray spectroscopy of the low and high states of the Seyfert 1 galaxy NGC 4051 with Chandra LETGS.

STEENBRUGGE K.C., FENOVCIK M., KAASTRA J.S., COSTANTINI E. and VERBUNT F.

Abstract (from CDS):

With the new generation of high-resolution X-ray spectrometers the understanding of warm absorbers in active galactic nuclei has improved considerably. However, the important questions regarding the distance and structure of the photoionised wind remain unsolved. To constrain the distance of the photoionised wind, we study the variability of the continuum, absorption, and, emission in one of the brightest and most variable low-luminosity AGN: the narrow-line Seyfert galaxy NGC 4051. We analyse two observations taken with the Low Energy Transmission Grating Spectrometer of Chandra. We investigated the spectral response to a sudden flux decrease by a factor of 5, which occurred during the second observation. We detect a highly ionised absorption component with an outflow velocity of -4670km/s, one of the highest outflow velocity components observed in a Seyfert 1 galaxy. Furthermore, this is one of the only observations whereby the X-ray observed absorption component is unaccompanied by a corresponding UV absorption component with the same outflow velocity. The spectra contain a relativistic OVIII Lyα line with properties similar to those determined for this source with XMM-Newton, and four absorption components spanning a range in ionisation parameter ξ between 0.07 and 3.19 (log values, and units of 10–9W.m). An emission component producing radiative recombination continua of CVI and CV appears during the low state. The black body temperature decreases with the drop in flux observed in the second observation. For all absorber components we exclude that the ionisation parameter linearly responded to the decrease in flux by a factor of 5. The variability of the absorber suggest that at least three out of four detected components are located in the range 0.02-1pc. For one component we only have a lower limit of 0.3pc. These distances are different from earlier suggestions.

Abstract Copyright:

Journal keyword(s): galaxies: Seyfert - quasars: individual: NGC 4051 - galaxies: active - X-rays: galaxies

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NGC 3783 Sy1 11 39 01.7095761008 -37 44 19.008597647   12.46 13.43 11.33 12.1 ~ 1500 0
2 NGC 4051 Sy1 12 03 09.6098828919 +44 31 52.693714606   11.08 12.92 9.94   ~ 2029 1
3 NGC 4253 Sy1 12 18 26.5155239433 +29 48 46.518670434   14.34 13.57     ~ 950 1
4 ESO 383-35 Sy1 13 35 53.7686909139 -34 17 44.139127597   13.89 13.61 8.9   ~ 1400 0
5 Mrk 279 Sy1 13 53 03.4356451470 +69 18 29.410672989   15.15 14.46     ~ 705 0
6 NGC 5548 Sy1 14 17 59.5401093128 +25 08 12.600227883   14.35 13.73     ~ 2445 0
7 NAME Ursa Major Cluster ClG 15 08.8 +67 07           ~ 388 0

    Equat.    Gal    SGal    Ecl

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2021.03.05-21:38:52

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