The Milky Way's bar structural properties from gravitational waves

Fuente: arXiv
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Autori principali: Wilhelm, Maite J. C., Korol, Valeriya, Rossi, Elena M., D'Onghia, Elena
Natura: Preprint
Pubblicazione: 2020
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author Wilhelm, Maite J. C.
Korol, Valeriya
Rossi, Elena M.
D'Onghia, Elena
author_facet Wilhelm, Maite J. C.
Korol, Valeriya
Rossi, Elena M.
D'Onghia, Elena
contents The Laser Interferometer Space Antenna (LISA) will enable Galactic gravitational wave (GW) astronomy by individually resolving $ > 10^4$ signals from double white dwarf (DWD) binaries throughout the Milky Way. In this work we assess for the first time the potential of LISA data to map the Galactic stellar bar and spiral arms, since GWs are unaffected by stellar crowding and dust extinction unlike optical observations of the bulge region. To achieve this goal we combine a realistic population of Galactic DWDs with a high-resolution N-Body simulation a galaxy in good agreement with the Milky Way. We then model GW signals from our synthetic DWD population and reconstruct the structure of the simulated Galaxy from mock LISA observations. Our results show that while the low signal contrast between the background disc and the spiral arms hampers our ability to characterise the spiral structure, the stellar bar will instead clearly appear in the GW map of the bulge. The bar length and bar width derived from these synthetic observations are underestimated, respectively within $1σ$ and at a level greater than $2σ$, but the resulting axis ratio agrees to well within $1σ$, while the viewing angle is recovered to within one degree. These are competitive constraints compared to those from electromagnetic tracers, and they are obtained with a completely independent method. We therefore foresee that the synergistic use of GWs and electromagnetic tracers will be a powerful strategy to map the bar and the bulge of the Milky Way.
format Preprint
id arxiv_https___arxiv_org_abs_2003_11074
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle The Milky Way's bar structural properties from gravitational waves
Wilhelm, Maite J. C.
Korol, Valeriya
Rossi, Elena M.
D'Onghia, Elena
Astrophysics of Galaxies
The Laser Interferometer Space Antenna (LISA) will enable Galactic gravitational wave (GW) astronomy by individually resolving $ > 10^4$ signals from double white dwarf (DWD) binaries throughout the Milky Way. In this work we assess for the first time the potential of LISA data to map the Galactic stellar bar and spiral arms, since GWs are unaffected by stellar crowding and dust extinction unlike optical observations of the bulge region. To achieve this goal we combine a realistic population of Galactic DWDs with a high-resolution N-Body simulation a galaxy in good agreement with the Milky Way. We then model GW signals from our synthetic DWD population and reconstruct the structure of the simulated Galaxy from mock LISA observations. Our results show that while the low signal contrast between the background disc and the spiral arms hampers our ability to characterise the spiral structure, the stellar bar will instead clearly appear in the GW map of the bulge. The bar length and bar width derived from these synthetic observations are underestimated, respectively within $1σ$ and at a level greater than $2σ$, but the resulting axis ratio agrees to well within $1σ$, while the viewing angle is recovered to within one degree. These are competitive constraints compared to those from electromagnetic tracers, and they are obtained with a completely independent method. We therefore foresee that the synergistic use of GWs and electromagnetic tracers will be a powerful strategy to map the bar and the bulge of the Milky Way.
title The Milky Way's bar structural properties from gravitational waves
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2003.11074