The nature of GW190425, a merger detected by the LIGO/Virgo Scientific Collaboration through gravitational wave radiation, is a mystery.  If it is a binary neutron star merger, then its estimated total mass of 3.4 Solar masses is significantly larger than that of the Milky Way's binary neutron star population, which we observe at radio wavelengths.  Luckily, binary neutron stars with orbital periods less than a few hours – i.e. progenitors of LIGO/Virgo mergers and descendants of radio detections at the same time – are prime targets for the LISA gravitational wave experiment. In this work we discuss whether LISA's observations can probe a population of GW190425-like binary neutron stars in our Milky Way and help us to understand their origin. Specifically, we show that LISA's measurement errors will allow us to identify GW190425-like binaries as a sub-population of a broader more radio-like looking population.

This work is published in MNRAS, arXiv:2012.03070 

In this paper we propose to use gravitational wave signals from double white dwarf binaries detectable by LISA for measuring the total stellar mass of the Milky Way satellite galaxies. Building upon the analogy with simple stellar population models, we demonstrated how the total stellar mass of the Milky Way satellites can be estimated from the number of associated LISA events. Using a fiducial double white dwarf evolution model we showed that satellite masses inside the Milky Way virial radius can be recovered within 1) a factor two if the star formation history is known and 2) within an order of magnitude even when marginalising over alternative star formation history models.  Importantly, we found that the accuracy of our method in some cases can match that of the mass estimated based on electromagnetic observations. Thus, with the addition of independent measurements based on gravitational wave observations, we can place stronger constraints on satellite masses, and we can gain a deeper understanding of their properties and co-evolution with the Milky Way.

This work is published in MNRAS Letters, arxiv:2010.05918

The data underlying this article and our code will be publicly available here.

In this paper, led by my former master student Martijn Wilhelm, we combine a realistic population of double white dwarfs with a high-resolution Galactic simulation in good agreement with current observations of the Milky Way. We then model gravitational wave signals from our synthetic double white dwarf population and reconstruct the structure of the Galaxy from mock LISA observations. Our results show that the stellar bar will clearly appear in the LISA map, however because of the low density contrast between the disc and the spiral arms the spiral structure of the Milky Way will be less clear. We find that gravitational wave observation will allow us to accurately define the bar's geometry by measuring its physical length, axis ratio and orientation angle with respect to us.

This work has been published in MNRAS, arXiv:2003.11074 

The data underlying this article is publicly available here. 

Binary systems made of two white dwarf stars in orbits of less than a couple of hours represent a unique opportunity for multi-messenger (electromagnetic + gravitational wave) studies. On one hand, we can detect their electromagnetic radiation with optical telescopes if they are eclipsing. On the other hand,  they can also be detected through gravitational wave radiation with LISA. In this paper, we compute the size of the sample of Galactic multi-messenger detections that could be observed with current and future optical facilities such as the Gaia mission and the Vera Rubin Observatory, and LISA in the next two decades. We show that Gaia, LSST and LISA have the potential to detect, respectively, around a few hundred, a thousand and tens of thousands double white dwarf binaries, out of which about 100 will be multi-messenger sources.

This work has been published in MNRAS, arXiv:1703.02555