2016A&A...588A.139M


Query : 2016A&A...588A.139M

2016A&A...588A.139M - Astronomy and Astrophysics, volume 588A, 139-139 (2016/4-1)

Anatomy of the AGN in NGC 5548.

MEHDIPOUR M., KAASTRA J.S., KRISS G.A., CAPPI M., PETRUCCI P.-O., DE MARCO B., PONTI G., STEENBRUGGE K.C., BEHAR E., BIANCHI S., BRANDUARDI-RAYMONT G., COSTANTINI E., EBRERO J., DI GESU L., MATT G., PALTANI S., PETERSON B.M., URSINI F. and WHEWELL M.

Abstract (from CDS):

We present our investigation into the long-term variability of the X-ray obscuration and optical-UV-X-ray continuum in the Seyfert 1 galaxy NGC 5548. In 2013 and 2014, the Swift observatory monitored NGC 5548 on average every day or two, with archival observations reaching back to 2005, totalling about 670ks of observing time. Both broadband spectral modelling and temporal rms variability analysis are applied to the Swift data. We disentangle the variability caused by absorption, due to an obscuring weakly-ionised outflow near the disk, from variability of the intrinsic continuum components (the soft X-ray excess and the power law) originating in the disk and its associated coronae. The spectral model that we apply to this extensive Swift data is the global model that we derived for NGC 5548 from analysis of the stacked spectra from our multi-satellite campaign of 2013 (including XMM-Newton, NuSTAR, and HST). The results of our Swift study show that changes in the covering fraction of the obscurer is the primary and dominant cause of variability in the soft X-ray band on timescales of 10 days to ∼5 months. The obscuring covering fraction of the X-ray source is found to range between 0.7 and nearly 1.0. The contribution of the soft excess component to the X-ray variability is often much less than that of the obscurer, but it becomes comparable when the optical-UV continuum flares up. We find that the soft excess is consistent with being the high-energy tail of the optical-UV continuum and can be explained by warm Comptonisation: up-scattering of the disk seed photons in a warm, optically thick corona as part of the inner disk. To this date, the Swift monitoring of NGC 5548 shows that the obscurer has been continuously present in our line of sight for at least 4 years (since at least February 2012).

Abstract Copyright: © ESO, 2016

Journal keyword(s): X-rays: galaxies - galaxies: active - galaxies: Seyfert - galaxies: individual: NGC 5548 - techniques: spectroscopic

Simbad objects: 4

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Number of rows : 4
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 3516 Sy1 11 06 47.4596406816 +72 34 07.189563769   13.12 12.40     ~ 1442 0
2 NGC 5548 Sy1 14 17 59.5401093128 +25 08 12.600227883   14.35 13.73     ~ 2468 0
3 Mrk 509 Sy1 20 44 09.7504131334 -10 43 24.724854084   13.35 13.12 10.7   ~ 1159 0
4 NGC 7469 Sy1 23 03 15.674 +08 52 25.28 12.60 13.00 12.34     ~ 1939 3

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2021.08.01-12:14:55

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