# Constraints on individual supermassive binary black holes using observations of PSR J1909-3744

## TL;DR

This study uses pulsar timing observations to search for gravitational waves from supermassive binary black hole candidates, setting upper limits on their chirp masses and GW strain amplitudes, and exploring methods to improve detection sensitivity.

## Contribution

It provides new upper limits on GW emissions from specific SMBBH candidates and analyzes how orbital parameter knowledge can enhance search sensitivity.

## Key findings

- No significant GW signals detected.
- Upper limits on chirp masses are established.
- Improved upper limits on GW strain amplitude by a factor of 2 to 7.

## Abstract

We perform a search for gravitational waves (GWs) from several supermassive binary black hole (SMBBH) candidates (NGC 5548, Mrk 231, OJ 287, PG 1302-102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of the pulsar PSR J1909$-$3744 obtained using the Parkes radio telescope. No statistically significant signals were found. We constrain the chirp masses of those SMBBH candidates and find the chirp mass of NGC 5548 and 3C 66B to be less than $2.4 \times 10^9\,\rm M_{\odot}$ and $2.5 \times 10^9\,\rm M_{\odot}$ (with 95% confidence), respectively. Our upper limits remain a factor of 3 to 370 above the likely chirp masses for these candidates as estimated from other approaches. The observations processed here provide upper limits on the GW strain amplitude that improve upon the results from the first Parkes Pulsar Timing Array data release by a factor of 2 to 7. We investigate how information about the orbital parameters can help improve the search sensitivity for individual SMBBH systems. Finally, we show that these limits are insensitive to uncertainties in the Solar System ephemeris model.