# Multiwavelength campaign on Mrk 509. XVI. Continued HST/COS monitoring of the far-ultraviolet spectrum

## TL;DR

This study uses coordinated UV and X-ray observations over several years to analyze the outflow properties of Mrk 509, revealing variability, density, and proximity of the absorbing gas to the active nucleus.

## Contribution

It provides new constraints on the location, physical conditions, and variability of the outflowing gas in Mrk 509 through multi-epoch, multiwavelength spectroscopy.

## Key findings

- Detected UV absorption line variability over 3-12 years.
- Constrained absorber densities to be greater than 10^3 cm^-3.
- Estimated absorber distances to be within 220 parsecs of the nucleus.

## Abstract

To elucidate the location, physical conditions, mass outflow rate, and kinetic luminosity of the outflow from the active nucleus of the Seyfert 1 galaxy Mrk 509 we used coordinated ultraviolet and X-ray spectral observations in 2012 to follow up our lengthier campaign conducted in 2009. We observed Mrk 509 with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) on 2012-09-03 and 2012-10-11 coordinated with X-ray observations using the High Energy Transmission Grating on the Chandra X-ray Observatory. Our far-ultraviolet spectra used grating G140L on COS to cover wavelengths from 920--2000 \AA\ at a resolving power of $\sim2000$, and gratings G130M and G160M to cover 1160--1750 \AA\ at a resolving power of $\sim15,000$. We detect variability in the blue-shifted UV absorption lines on timescales spanning 3--12 years. The inferred densities in the absorbing gas are greater than log $n \rm~cm^{-3} \sim 3$. For ionization parameters ranging over log $U = -1.5 \rm~to~-0.2$, we constrain the distances of the absorbers to be closer than 220 pc to the active nucleus. The impact on the host galaxy appears to be confined to the nuclear region.