| Name: | Kewal Anand |
| Affiliation: | Indian Institute of Technology Kanpur, India |
| Conference ID : | ASI2024_471 |
| Title : | Constraining neutron star mass and moment of inertia from QPO triplets observed in 4U 1728-34 from AstroSat/LAXPC observation |
| Authors : | Kewal Anand1, J. S. Yadav2,5, Ranjeev Misra3, Pankaj Jain2, Dipankar Bhattacharya4, Umang Kumar4 |
| Authors Affiliation: | 1 Kewal Anand Department of Physics, Indian Institute of Technology Kanpur, Kanpur- 208016, India
2 J. S. Yadav, Pankaj Jain Department of Space, Planetary & Astronomical Sciences & Engineering, Indian Institute of Technology Kanpur, Kanpur- 208016, India
3 Ranjeev Misra Inter-University Center for Astronomy and Astrophysics, Pune-411007, India
4 Dipankar Bhattacharya, Umang Kumar Department of Physics, Ashoka University, Sonepat-131029, India
5 J. S. Yadav Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai-400005, India |
| Mode of Presentation: | Oral |
| Abstract Category : | High Energy Phenomena, Fundamental Physics and Astronomy |
| Abstract : | In this work, we report the detection of three simultaneous quasi-periodic oscillations (QPOs) at ~ 40 Hz, ~ 800 Hz, and ~1100 Hz along with a broad-band noise at ~ 150 Hz from the AstroSat\LAXPC observation of NS-LMXB 4U 1728-34. We obtain thirteen sets of QPO triplets in time-resolved power density spectra (PDS) for a particular observation, and these QPO triplet frequencies are found to evolve with time, showing a remarkable correlation among each other. Using the relativistic precession model (RPM), in which low-frequency QPO and lower kHz QPO frequencies are identified as twice of nodal and periastron precessions frequencies and upper kHz QPO frequency as orbital frequency, and known spin frequency of neutron star we could deteremine a well-constrained mass and moment of inertia of the neutron star to be M = 1.92±0.01M⊙ and I45/M0 = 1.07±0.01 respectively. These neutron star parameters obtained from our work seem to favor some stiffer equations of state of neutron stars. |
