Multiwavelength Campaign on Mrk 509 X. Lower limit on the distance of the absorber from HST COS and STIS spectroscopy

Abstract

Active Galactic Nuclei often show evidence of photoionized outflows. A major uncertainty in models for these outflows is the distance ($R$) to the gas from the central black hole. In this paper we use the HST/COS data from a massive multi-wavelength monitoring campaign on the bright Seyfert I galaxy Mrk 509, in combination with archival HST/STIS data, to constrain the location of the various kinematic components of the outflow. We compare the expected response of the photoionized gas to changes in ionizing flux with the changes measured in the data using the following steps: 1) We compare the column densities of each kinematic component measured in the 2001 STIS data with those measured in the 2009 COS data; 2) We use time-dependent photionization calculations with a set of simulated lightcurves to put statistical upper limits on the hydrogen number density that are consistent with the observed small changes in the ionic column densities; 3) From the upper limit on the number density, we calculate a lower limit on the distance to the absorber from the central source via the prior determination of the ionization parameter. Our method offers two improvements on traditional timescale analysis. First, we account for the physical behavior of AGN lightcurves. Second, our analysis accounts for the quality of measurement in cases where no changes are observed in the absorption troughs. The very small variations in trough ionic column densities (mostly consistent with no change) between the 2001 and 2009 epochs allow us to put statistical lower limits on the distance between 100--200 pc for all the major UV absorption components at a confidence level of 99%. These results are mainly consistent with the independent distance estimates derived for the warm absorbers from the simultaneous X-ray spectra.

arXiv commentAccepted to A&A (06 APR 2012)

References in corpus (31)

• On the Absorption of X-rays in the Interstellar Medium
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• The Interstellar Environment of our Galaxy
• The Cosmic Origins Spectrograph
• Highly-Ionized High-Velocity Gas in the Vicinity of the Galaxy
• High Velocity Clouds: Building Blocks of the Local Group
• Time-Dependent Ionization in Radiatively Cooling Gas
• The "Solar Model Problem" Solved by the Abundance of Neon in Stars of the Local Cosmos
• Distribution and Kinematics of O VI in the Galactic Halo
• A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star Formation in the Milky Way
• On the metallicity gradient of the Galactic disk
• A Large Reservoir of Ionized Gas in the Galactic Halo: Ionized Silicon in High-Velocity and Intermediate-Velocity Clouds
• X-ray Absorption Line Spectroscopy of the Galactic Hot Interstellar Medium
• A Survey of O VI, C III, and H I in Highly Ionized High-Velocity Clouds
• Multiwavelength campaign on Mrk 509. III. The 600 ks RGS spectrum: unravelling the inner region of an AGN
• Highly Ionized High Velocity Clouds: Intergalactic Gas in the Local Group or Distant Gas in the Galactic Halo?
• A FUSE survey of high-latitude Galactic molecular hydrogen
• XMM-Newton observation of 4U 1820-30: Broad band spectrum and the contribution of the cold interstellar medium
• Highly Ionized High-Velocity Clouds toward PKS 2155-304 and Markarian 509
• High-Resolution X-ray Spectroscopy of the Interstellar Medium
• Thermal radiation processes
• X-ray and UV spectroscopy of Galactic diffuse hot gas along the LMC X--3 sight line
• FUSE Observations of Intrinsic Absorption in the Seyfert 1 Galaxy Mrk 509
• Multiwavelength campaign on Mrk 509. I. Variability and spectral energy distribution
• Properties of warm absorbers in active galaxies: a systematic stability curve analysis
• Multiwavelength campaign on Mrk 509. VI. HST/COS observations of the far-ultraviolet spectrum
• The Metallicity Gradient of the Thick Disk Based on Red Horizontal Branch Stars From SDSS DR8
• Multiwavelength campaign on Mrk 509. II. Analysis of high-quality Reflection Grating Spectrometer spectra
• Effective area calibration of the Reflection Grating Spectrometers of XMM-Newton. I. X-ray spectroscopy of the Crab nebula
• Multiwavelength campaign on Mrk 509. V. Chandra-LETGS observation of the ionized absorber
• Global Hot Gas in and around the Galaxy

Cited by in corpus (12)

• ISM composition through X-ray spectroscopy of LMXBs
• Ultrafast outflows disappear in high radiation fields
• Multiwavelength campaign on Mrk 509. XIII. Testing ionized-reflection models on Mrk 509
• Multi-wavelength campaign on NGC7469 I. The rich 640 ks RGS spectrum
• High Resolution X-ray Spectroscopy of the Local Hot Gas along the 3C 273 Sightline
• A deep X-ray view of the bare AGN Ark 120. I. Revealing the Soft X-ray Line Emission
• Suzaku and XMM-Newton Observations of the North Polar Spur: Charge Exchange or ISM Absorption?
• Unveiling the environment surrounding LMXB SAX J1808.4-3658
• Multiwavelength campaign on Mrk 509 XIV. Chandra HETGS spectra
• The warm absorber in the radio-loud quasar 4C +74.26
• The OVI mystery: mismatch between X-ray and UV column densities
• A constant pressure model for the warm absorber in Mrk 509