Multiwavelength campaign on Mrk 509. II. Analysis of high-quality Reflection Grating Spectrometer spectra

TL;DR

This paper presents a detailed spectral analysis of Mrk 509 using high-quality RGS data from XMM-Newton, improving calibration and spectral fitting methods to better understand the galaxy's outflow properties.

Contribution

It introduces enhanced calibration and data processing techniques for RGS spectra, enabling more precise measurements of spectral features in Mrk 509.

Findings

Resolved two velocity troughs in UV spectra.

Achieved improved wavelength calibration accuracy.

Enhanced spectral data quality with multi-pointing mode.

Abstract

We study the bright Seyfert 1 galaxy Mrk~509 with the Reflection Grating Spectrometers (RGS) of XMM-Newton using the RGS multi-pointing mode of XMM-Newton for the first time in order to constrain the properties of the outflow in this object. We want to obtain the most accurate spectral properties from the 600 ks spectrum of Mrk 509 which has excellent statistical quality. We derive an accurate relative calibration for the effective area of the RGS, derive an accurate absolute wavelength calibration, improve the method for adding time-dependent spectra and enhance the efficiency of the spectral fitting by two orders of magnitude. We show the major improvement of the spectral data quality due to the use of the new RGS multi-pointing mode of XMM-Newton. We illustrate the gain in accuracy by showing that with the improved wavelength calibration the two velocity troughs observed in UV spectra are resolved.