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Iron emission lines at 6.4-6.97 keV, identified with Kalpha radiative transitions, are among the strongest discrete features in the X-ray band. These are one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disk around a compact object. In this paper we present a recent Suzaku observation, 100-ks effective exposure, of the atoll source and X-ray burster 4U 1705-44, where we clearly detect signatures of a reflection component which is distorted by the high-velocity motion in the accretion disk. The reflection component consists of a broad iron line at about 6.4 keV and a Compton bump at high X-ray energies, around 20 keV. All these features are consistently fitted with a reflection model, and we find that in the hard state the smearing parameters are remarkably similar to those found in a previous XMM-Newton observation performed in the soft state. In particular, we find that the inner disk radius is Rin = 17 +/- 5 Rg (where Rg is the Gravitational radius, GM/c^2), the emissivity dependence from the disk radius is -2.5 +/- 0.5, the inclination angle with respect to the line of sight is i = 43 +/- 5 degrees, and the outer radius of the emitting region in the disk is Rout > 200 Rg. We note that the accretion disk does not appear to be truncated at large radii, although the source is in a hard state at about 3 % of the Eddington luminosity for a neutron star. We also find evidence of a broad emission line at low energies, at 3.03 +/- 0.03 keV, compatible with emission from mildly ionized Argon (Ar XVI-XVII). Argon transitions are not included in the self-consistent reflection models that we used and we therefore added an extra component to our model to fit this feature. The low energy line appears compatible with being smeared by the same inner disk parameters found for the reflection component.
The low-mass X-ray binary 4U1705-44 exhibits dramatic long-term X-ray time variability with a timescale of several hundred days. The All-Sky Monitor (ASM) aboard the Rossi X-ray Timing Explorer (RXTE) and the Japanese Monitor of All-sky X-ray Image (
Aims: A hard X-ray shortage, implying the cooling of the corona, was observed during bursts of IGR J17473-272, 4U 1636-536, Aql X-1, and GS 1826-238. Apart from these four sources, we investigate here an atoll sample, in which the number of bursts fo
4U 1705-44 is one of the most-studied type I X-ray burster and Atoll sources. This source represents a perfect candidate to test different models proposed to self-consistently track the physical changes occurring between different spectral states bec
We present $emph{NuSTAR}$ observations of neutron star (NS) low-mass X-ray binaries: 4U 1636-53, GX 17+2, and 4U 1705-44. We observed 4U 1636-53 in the hard state, with an Eddington fraction, $F_{mathrm{Edd}}$, of 0.01; GX 17+2 and 4U 1705-44 were in
In this paper, we present the first results of spectral and timing properties of the atoll source 4U 1705-44 using $sim$ 100 ks data obtained with Large Area X-ray Proportional Counter (LAXPC) onboard {it AstroSat}. The source was in the high-soft st