Search Publications
Putting all the X in one basket: Updated X-ray constraints on sub-GeV Dark Matter
Pinetti, Elena; Fornengo, Nicolao; Cirelli, Marco +2 more
Sub-GeV dark matter particles can annihilate or decay producing e ± pairs which upscatter the low-energy photon fields in the Galaxy and generate an X-ray emission (via the Inverse Compton effect). Using X-ray data from XMM-NEWTON, INTEGRAL, NUSTAR and SUZAKU, we derive new constraints on this class of dark matter (DM). In the annihilat…
Thermal and chemical properties of the eROSITA bubbles from Suzaku observations
Mathur, Smita; Gupta, Anjali; Kingsbury, Joshua +2 more
The X-ray bright bubbles at the Galactic Centre provide an opportunity to understand the effects of feedback on galaxy evolution. The shells of the eROSITA bubbles show enhanced X-ray emission over the sky background. Previously, these shells were assumed to have a single temperature component and to trace the shock-heated lower-temperature halo g…
Multi-epoch hard X-ray view of Compton-thick AGN Circinus Galaxy
Gandhi, Poshak; Ricci, Claudio; Kayal, Abhijit +4 more
The circumnuclear material around active galactic nuclei (AGNs) is one of the essential components of the obscuration-based unification model. However, our understanding of the circumnuclear material in terms of its geometrical shape, structure, and its dependence on accretion rate is still debated. In this paper, we present the multi-epoch broad-…
Further Evidence for the 9 s Pulsation in LS 5039 from NuSTAR and ASCA
Enoto, Teruaki; Makishima, Kazuo; Takahashi, Tadayuki +2 more
The present study aims to reinforce the evidence for the ~9 s pulsation in the gamma-ray binary LS 5039, derived from a Suzaku observation in 2007 and a NuSTAR observation in 2016. Through a reanalysis of the NuSTAR data incorporating the orbital Doppler correction, the 9.0538 s pulsation was confirmed successfully even in the 3-10 keV range, wher…
The soft X-ray background with Suzaku. II. Supervirial temperature bubbles?
Sato, Kosuke; Yamasaki, Noriko Y.; Matsushita, Kyoko +4 more
Observations of the hot X-ray emitting interstellar medium in the Milky Way are important for studying the stellar feedback and for understanding the formation and evolution of galaxies. We present measurements of the soft X-ray background emission for 130 Suzaku observations at 75° < l < 285° and |b| > 15°. With the standard soft X-ray b…
NGC 4388: a test case for relativistic disc reflection and Fe K fluorescence features
LaMassa, S.; Yaqoob, Tahir; Tzanavaris, P.
We present a new analysis of the Suzaku X-ray spectrum of the Compton-thin Seyfert 2 galaxy NGC 4388. The spectrum above ~2 keV can be described by a remarkably simple and rather mundane model, consisting of a uniform, neutral spherical distribution of matter, with a radial column density of $2.58\pm 0.02 \times 10^{23} \ \rm cm^{-2}$, and an Fe a…
Spectral analysis of the Galactic supernova remnant Kesteven 69 with Suzaku
Yamauchi, Shigeo; Pannuti, Thomas G.
The results of a Suzaku observation of the supernova remnant (SNR) Kesteven 69 = G21.8-0.6 are presented. To estimate the sky background precisely, we conducted a simultaneous fit of the source region spectrum with the background region spectrum and found that the SNR spectrum is well represented by a two-component ionizing plasma model composed o…
Suzaku spectral analysis of an X-ray emitting plasma in the supernova remnant G352.7-0.1
Nobukawa, Masayoshi; Nobukawa, Kumiko K.; Yamauchi, Shigeo +1 more
The results of a Suzaku observation of the supernova remnant (SNR) G352.7-0.1 are presented in this paper. We conducted spectral analysis based on careful sky background estimation and found an emission line from Al at 1.6 keV, in addition to previously detected emission lines from Mg, Si, S, Ar, Ca, and Fe ions. The X-ray spectrum in the 0.7-10 k…
Suzaku and Chandra study of diffuse X-ray emission from the massive star-forming region RCW 38
Ezoe, Yuichiro; Odaka, Hirokazu; Fukushima, Aoto
In some massive star-forming regions, diffuse X-ray emission has been observed. It can be classified as thermal emission from sub- or several-keV plasmas, non-thermal emission represented by the power law, or a mixture of them. We have studied the nearby (~1.7 kpc) young massive star-forming region RCW 38. In a previous study, non-thermal diffuse …
Initial state of the recombining plasma in supernova remnant W 28
Nobukawa, Masayoshi; Nobukawa, Kumiko K.; Yamauchi, Shigeo +2 more
We have investigated supernova remnant (SNR) W 28 using Suzaku archival data, and we report here the results of our spatially resolved analyses. We carried out spectral analyses using a recombining-plasma (RP) model with element-dependent initial ionization temperatures, obtaining ~0.5 keV for Ne, ~0.7 keV for Mg, ~1.0 keV for Si, ~1.2 keV for S, …