Broad-band X-ray spectral analysis of the Seyfert 1 galaxy GRS 1734-292

We discuss the broad-band X-ray spectrum of GRS 1734-292 obtained from non-simultaneous XMM-Newton and NuSTAR (Nuclear Spectroscopic Telescope Array) observations, performed in 2009 and 2014, respectively. GRS1734-292 is a Seyfert 1 galaxy, located near the Galactic plane at z = 0.0214. The NuSTAR spectrum (3-80 keV) is dominated by a primary power-law continuum with Γ = 1.65 ± 0.05 and a high-energy cut-off E_c=53^{+11}_{-8} keV, one of the lowest measured by NuSTAR in a Seyfert galaxy. Comptonization models show a temperature of the coronal plasma of kT_e=11.9^{+1.2}_{-0.9} keV and an optical depth, assuming a slab geometry, τ =2.98^{+0.16}_{-0.19} or a similar temperature and τ =6.7^{+0.3}_{-0.4} assuming a spherical geometry. The 2009 XMM-Newton spectrum is well described by a flatter intrinsic continuum (Γ = 1.47^{+0.07}_{-0.03}) and one absorption line due to Fe xxv Kα produced by a warm absorber. Both data sets show a modest iron Kα emission line at 6.4 keV and the associated Compton reflection, due to reprocessing from neutral circumnuclear material.