Multiwavelength campaign on Mrk 509 V. Chandra-LETGS observation of the ionized absorber

Context. We present here the results of a 180 ks Chandra-LETGS observation as part of a large multi-wavelength campaign on Mrk 509. Aims. We study the warm absorber in Mrk 509 and use the data from a simultaneous HST-COS observation in order to assess whether the gas responsible for the UV and X-ray absorption are the same. Methods. We analyzed the LETGS X-ray spectrum of Mrk 509 using the SPEX fitting package. Results. We detect several absorption features originating in the ionized absorber of the source, along with resolved emission lines and radiative recombination continua. The absorption features belong to ions with, at least, three distinct ionization degrees. The lowest ionized component is slightly redshifted (Δv = 73 km s-1) and is not in pressure equilibrium with the others, and therefore it is not likely part of the outflow, possibly belonging to the interstellar medium of the host galaxy. The other components are outflowing at velocities of −196 and −455 km s-1, respectively. The source was observed simultaneously with HST-COS, finding 13 UV kinematic components. At least three of them can be kinematically associated with the observed X-ray components. Based on the HST-COS results and a previous FUSE observation, we find evidence that the UV absorbing gas might be co-located with the X-ray absorbing gas and belong to the same structure.