National conference on REcent Trends in the study of Compact Objects (RETCO-V): Theory and Observation

AstroSat-NuSTAR monitoring of GX 339-4 and H 1743-322 : Broadband spectro-temporal analyses

Apr 3, 2023, 4:50 PM

15m

Auditorium (Kodaikanal Solar Observatory)

Black Hole: Observations Black Hole: Observations

Speaker

ANEESHA U (IIT GUWAHATI)

Description

We present the results from X-ray broadband spectro-temporal analyses of recurrent outbursting sources GX 339$-$4 and H 1743$-$322 using AstroSat and NuSTAR archival observations carried out during $2016-2022$. GX 339$-$4 was found to be making transition from quiescence to outburst, and the wide-band spectral analyses results during outbursts shows that GX 339$-$4 was in hard ($k{T}_{\mathrm{b}\mathrm{b}}=0.29-0.51$ keV, $\mathrm{\Gamma }=1.46-2.06$ and $L_{\mathrm{b}\mathrm{o}\mathrm{l}}=0.27-8.22\mathrm{\%}$ of Eddington luminosity $L_{\mathrm{E}\mathrm{d}\mathrm{d}}$), intermediate ($k{T}_{\mathrm{i}\mathrm{n}}=0.75-1.08$ keV, $\mathrm{\Gamma }=1.71-2.49$, $L_{\mathrm{b}\mathrm{o}\mathrm{l}}=6.74-9.11\mathrm{\%}{L}_{\mathrm{E}\mathrm{d}\mathrm{d}}$) and soft states ($k{T}_{\mathrm{i}\mathrm{n}}=0.51-0.93$ keV, $\mathrm{\Gamma }=1.67-3.74$, $L_{\mathrm{b}\mathrm{o}\mathrm{l}}=9.06-15.27\mathrm{\%}{L}_{\mathrm{E}\mathrm{d}\mathrm{d}}$). Instead H 1743$-$322 found to make transition from quiscence to only hard state ($\mathrm{\Gamma }=1.57-1.73$, $L_{\mathrm{b}\mathrm{o}\mathrm{l}}=3.07-6.61\mathrm{\%}{L}_{\mathrm{E}\mathrm{d}\mathrm{d}}$). Timing variability studies revealed the presence of Quasi-periodic Oscillations (QPOs) in GX 339$-$4 with frequencies varying between $0.10-5.37$ Hz along with harmonics. We detect type C QPOs in H 1743$-$322 with frequencies in the range $0.22-1.01$ Hz along with distinct harmonics. The energy dependent power density spectral study shows that, in GX 339$-$4 fundamental QPO and harmonics are present only in $3-20$ keV. Whereas in H 1743$-$322, the fundamental QPO is present only in $3-40$ keV energy band and the harmonic is not significant above $\sim 20$ keV. We discuss these observational findings in the context of accretion dynamics around black hole binary.