A preliminary forecast for cosmological parameter estimation with gravitational-wave standard sirens from TianQin

Abstract

TianQin is a space-based gravitational-wave observatory scheduled to be\nlaunched in the 2030s. In this work, we make a preliminary forecast for the\ncosmological parameter estimation with the gravitational-wave standard siren\nobservation from TianQin. We simulate the standard siren data of TianQin based\non its 5-year observation after the completion of construction. In the\nsimulation, three models for the population of massive black hole binary\n(MBHB), i.e., pop III, Q3nod, and Q3d, are considered to predict the event\nnumbers of MBHB mergers. We find that: (i) among the three MBHB models, the\nQ3nod model can provide the tightest constraints on the cosmological\nparameters; (ii) TianQin's standard siren observation can effectively break the\nparameter degeneracies inherent in the cosmic microwave background observation;\nand (iii) the future standard siren observation from TianQin can significantly\nimprove the cosmological parameter estimation under the current mainstream\nelectromagnetic observations.\n