Journal
ASTRONOMY & ASTROPHYSICS
Volume 549, Issue -, Pages -Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201219956
Keywords
galaxies: active; galaxies: individual: Mrk 509; galaxies: Seyfert; X-rays: galaxies
Categories
Funding
- ESA Member States
- USA (NASA)
- NWO, the Netherlands Organization for Scientific Research
- CNES
- French GDR PCHE
- ASI-INAF [I/088/06/0]
- NASA/XMM-Newton Guest Investigator grant [NNX09AR01G]
- NASA through the Space Telescope Science Institute [12022]
- NASA [NAS5-26555]
- ISF
- STFC Postdoctoral Fellowship
- Polish MNiSW [N N203 581240, 362/1/N-INTEGRAL/2008/09/0]
- UK Science & Technology Facilities Council (STFC)
- EU Marie Curie Intra-European Fellowship [FP7-PEOPLE- 2009-IEF-254279]
- Comite Mixto ESO - Gobierno de Chile
- STFC [ST/F007019/1, ST/H00260X/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/F007019/1, ST/H00260X/1] Funding Source: researchfish
- UK Space Agency [ST/G008868/1] Funding Source: researchfish
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The origin of the different spectral components present in the high-energy (UV to X-rays/gamma-rays) spectra of Seyfert galaxies is still being debated a lot. One of the major limitations, in this respect, is the lack of really simultaneous broad-band observations that allow us to disentangle the behavior of each component and to better constrain their interconnections. The simultaneous UV to X-rays/gamma rays data obtained during the multiwavelength campaign on the bright Seyfert 1 Mrk 509 are used in this paper and tested against physically motivated broad band models. Mrk 509 was observed by XMM-Newton and INTEGRAL in October/November 2009, with one observation every four days for a total of ten observations. Each observation has been fitted with a realistic thermal Comptonization model for the continuum emission. Prompted by the correlation between the UV and soft X-ray flux, we used a thermal Comptonization component for the soft X-ray excess. We also included a warm absorber and a reflection component, as required by the precise studies previously done by our consortium. The UV to X-ray/gamma-ray emission of Mrk 509 can be well fitted by these components. The presence of a relatively hard high-energy spectrum points to the existence of a hot (kT similar to 100 keV), optically-thin (tau similar to 0.5) corona producing the primary continuum. In contrast, the soft X-ray component requires a warm (kT similar to 1 keV), optically-thick (tau similar to 10-20) plasma. Estimates of the amplification ratio for this warm plasma support a configuration relatively close to the theoretical configuration of a slab corona above a passive disk. An interesting consequence is the weak luminosity-dependence of its emission, which is a possible explanation of the roughly constant spectral shape of the soft X-ray excess seen in AGNs. The temperature (similar to 3 eV) and flux of the soft-photon field entering and cooling the warm plasma suggests that it covers the accretion disk down to a transition radius R-in of 10-20 R-g. This plasma could be the warm upper layer of the accretion disk. In contrast, the hot corona has a more photon-starved geometry. The high temperature (similar to 100 eV) of the soft-photon field entering and cooling it favors a localization of the hot corona in the inner flow. This soft-photon field could be part of the comptonized emission produced by the warm plasma. In this framework, the change in the geometry (i.e. R-in) could explain most of the observed flux and spectral variability.
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