Resolving dichotomy in compact objects through continuous gravitational waves observation

Kalita, Surajit; Mondal, Tushar; Tout, Christopher A.; Bulik, T.; Mukhopadhyay, Banibrata

doi:10.1093/mnras/stab2625

Cited by 6 publications

(4 citation statements)

References 65 publications

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“…We solve Equations ( 17) and (18) simultaneously to obtain Ω(t) and χ(t) assuming poloidal field-dominated NSs and then calculate the cumulative S/N for various detectors (Kalita et al 2020(Kalita et al , 2021. Figure 18 shows the S/N as a function of time for poloidal field-dominated NSs with different field strengths at the pole, i.e., 10 15 and 10 12 G. The B P is larger in the first case; thus, Ω and χ decrease rapidly with time due to the large L D .…”

Section: Possible Detection Of Massive Poloidally Dominated Ns Pulsarsmentioning

confidence: 99%

Detection Possibility of Continuous Gravitational Waves from Rotating Magnetized Neutron Stars

Das,

Mukhopadhyay

2023

ApJ

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In recent decades, several neutron stars (NSs), particularly pulsars, with masses of M > 2 M ⊙ have been observed. On the other hand, the existence of massive white dwarfs, even violating the Chandrasekhar mass limit, was inferred from the peak luminosities of Type Ia supernovae. Hence, there is a generic question of the origin of massive compact objects. Here we explore the existence of massive, magnetized, rotating NSs with the soft and steep equations of state by solving axisymmetric stationary stellar equilibria in general relativity. For our purposes, we consider the Einstein equation solver for stellar structure XNS code. Such rotating NSs with magnetic fields and rotation axes misaligned, and hence a nonzero obliquity angle, can emit continuous gravitational waves (GWs), which can be detected by upcoming detectors, e.g., the Einstein Telescope, etc. We discuss the decay of the magnetic field, angular velocity, and obliquity angle with time due to angular momentum extraction by GWs and dipole radiation, which determine the timescales related to the GW emission. Further, in the Alfvén timescale, a differentially rotating, massive proto-NS rapidly settles into a uniformly rotating, less massive NS due to magnetic braking and viscosity. These explorations suggest that detecting massive NSs is challenging and sets a timescale for detection. We calculate the signal-to-noise ratio of GW emission, which confirms that any detector cannot detect them immediately, but that they are detectable by the Einstein Telescope and Cosmic Explorer over months of integration time, leading to direct detection of NSs.

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Section: Possible Detection Of Massive Poloidally Dominated Ns Pulsarsmentioning

confidence: 99%

Detection Possibility of Continuous Gravitational Waves from Rotating Magnetized Neutron Stars

Das,

Mukhopadhyay

2023

ApJ

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“…In such cases, even the EoSs, which are considered non-physical, might not be ruled out if they are affected by NC. In the future, GW observations may detect numerous massive WDs and NSs [33,62,63], allowing us to constrain more EoSs and examine the NC effect on these compact objects more closely. If observed masses and radii of WDs and NSs follow the respective predicted mass-radius relations based on NC, it would be a direct confirmation for the existence of NC at scales far away from the Planck scale.…”

Section: Discussionmentioning

confidence: 99%

Massive Neutron Stars and White Dwarfs as Noncommutative Fuzzy Spheres

Kalita

Mukhopadhyay

2022

Universe

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Over the last couple of decades, there have been direct and indirect evidences for massive compact objects than their conventional counterparts. A couple of such examples are super-Chandrasekhar white dwarfs and massive neutron stars. The observations of more than a dozen peculiar over-luminous type Ia supernovae predict their origins from super-Chandrasekhar white dwarf progenitors. On the other hand, recent gravitational wave detection and some pulsar observations provide arguments for massive neutron stars, lying in the famous mass-gap between lowest astrophysical black hole and conventional highest neutron star masses. We show that the idea of a squashed fuzzy sphere, which brings in noncommutative geometry, can self-consistently explain either of the massive objects as if they are actually fuzzy or squashed fuzzy spheres. Noncommutative geometry is a branch of quantum gravity. If the above proposal is correct, it will provide observational evidences for noncommutativity.

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“…We solve equations ( 13) and ( 14) simultaneously to obtain Ω(t) and χ(t) assuming poloidal field dominated NSs and then calculate the cumulative SNR for various detectors (Kalita et al 2020(Kalita et al , 2021. Fig.…”

Section: Possible Detection Of Massive Poloidally Dominated Neutron S...mentioning

confidence: 99%

Detection possibility of continuous gravitational waves from rotating magnetized neutron stars

Das¹,

Mukhopadhyay²

2023

Preprint

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In the past decades, several neutron stars (NSs), particularly pulsars, with mass M > 2M have been observed. On the other hand, the existence of massive white dwarfs (WDs), even violating Chandrasekhar mass-limit, was inferred from the peak luminosities of type Ia supernovae. Hence, there is a generic question of the origin of massive compact objects. Here we explore the existence of massive, magnetized, rotating NSs with soft and steep equation of states (EoSs) by solving axisymmetric stationary stellar equilibria in general relativity. For our purpose, we consider the Einstein equation solver for stellar structure XNS code. Such rotating NSs with magnetic field and rotation axes misaligned, hence with non-zero obliquity angle, can emit continuous gravitational waves (GW), which can be detected by upcoming detectors, e.g., Einstein Telescope, etc. We discuss the decays of magnetic field, angular velocity and obliquity angle with time, due to angular momentum extraction by GW and dipole radiation, which determine the timescales related to the GW emission. Further, in the Alfvén timescale, a differentially rotating, massive proto-NS rapidly settles into an uniformly rotating, less massive NS due to magnetic braking and viscosity. These explorations suggest that detecting massive NSs is challenging and sets a timescale for detection. We calculate the signal-to-noise ratio of GW emission, which confirms that any detector cannot detect them immediately, but detectable by Einstein Telescope, Cosmic Explorer over months of integration time, leading to direct detection of NSs.

show abstract

Resolving dichotomy in compact objects through continuous gravitational waves observation

Cited by 6 publications

References 65 publications

Detection Possibility of Continuous Gravitational Waves from Rotating Magnetized Neutron Stars

Detection Possibility of Continuous Gravitational Waves from Rotating Magnetized Neutron Stars

Massive Neutron Stars and White Dwarfs as Noncommutative Fuzzy Spheres

Detection possibility of continuous gravitational waves from rotating magnetized neutron stars

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