Search Publications
The X-ray rise and fall of the symbiotic recurrent nova system T CrB
Sacchi, Andrea; Toalá, Jesús A.; González-Martín, Omaira +1 more
We present the analysis of publicly available NuSTAR, Suzaku, and XMM-Newton observations of the symbiotic recurrent nova T CrB covering the 2006.77-2022.66 yr period. The X-ray spectra are analysed by adopting a model that includes a reflection component produced by the presence of a disc that mimics the accretion disc and the immediate surroundi…
Long-term X-ray temporal and spectral study of a Seyfert galaxy Mrk 6
Naik, Sachindra; Jana, Arghajit; Kumari, Neeraj +3 more
We present a long-term X-ray study of a nearby Active Galactic Nucleus Mrk 6, utilizing observations from XMM-Newton, Suzaku, Swift, and NuSTAR observatories, spanning 22 years from 2001 to 2022. From timing analysis, we estimated variance, normalized variance, and fractional rms amplitude in different energy bands.The temporal study shows fractio…
Observational clues to the magnetic evolution of magnetars
Enoto, Teruaki; Makishima, Kazuo; Uchida, Nagomi
Utilizing four archival X-ray data sets taken with the Hard X-ray Detector onboard Suzaku, timing studies were performed on three magnetars, 1E 1841-045 (observed in 2006), SGR 0501+4516 (2008), and 1RXS J170849.0-400910 (2009 and 2010). Their pulsations were reconfirmed, typically in an energy range of 12-50 keV. The 11.783 s pulses of 1E 1841-04…
X-ray flux and spectral variability of the blazar OJ 287 with Suzaku
Gupta, Alok C.; Wiita, Paul J.; Xu, Haiguang +4 more
We present analyses of Suzaku XIS light curves and spectra of the BL Lac object OJ 287 with observations positioned primarily around proposed recurrent optical outbursts. The first two observations were performed in 2007 April 10-13 (epoch 1) and 2007 November 7-9 (epoch 2) that, respectively, correspond to a low and a high optical state and which…
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-…
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…
Lamp-post with an outflow and the hard state of Cyg X-1
Szanecki, Michał; Niedźwiecki, Andrzej; Klepczarek, Łukasz
Relativistic reflection observed in the hard states of accreting black holes (BH) often shows a weak amplitude relative to the main Comptonization component, which may result from either a disc truncation or a non-isotropy of the X-ray source, e.g. due to a motion away from the reflector. We investigate here the latter case, assuming that the X-ra…
Broad-band X-ray spectral study of nuclear structure in local obscured radio galaxies
Ueda, Yoshihiro; Ricci, Claudio; Ogawa, Shoji +6 more
Radio galaxies are a key population to understand the importance of relativistic jets in active galactic nucleus (AGN) feedback. We present the results of a systematic, broad-band X-ray spectral analysis of hard X-ray selected radio galaxies to investigate their nuclear structures. In this study, we focus on the seven most radio-loud, X-ray obscur…
Unravelling optical and X-ray properties of the disc-dominated intermediate polar IGR J15094-6649
Pandey, J. C.; Scaringi, Simone; Schwope, Axel +5 more
We present analyses of an Intermediate Polar, IGR J15094-6649, based on the archival optical data obtained from the Transiting Exoplanet Survey Satellite (TESS) and X-ray data obtained from the Suzaku, NuSTAR, and Neil Gehrels Swift Observatory (Swift). Present analysis confirms and refines the previously reported spin period of IGR J15094-6649 as…
Hot accretion flows in low-luminosity active galactic nuclei in NGC 4258 and NGC 7213
Szanecki, Michał; Niedźwiecki, Andrzej; Wojaczyński, Rafał
We study the high energy emission of two active galactic nuclei (AGNs), NGC 4258 and NGC 7213. We directly apply the general-relativistic hot flow model, KERRFLOW, to the archival BeppoSAX, NuSTAR, and Suzaku observations of these objects. Most of these data sets indicate that about 10-20 per cent of the accretion power is used for the direct heat…