1
$\begingroup$

I have found some papers (like this one: https://www.aanda.org/articles/aa/full_html/2009/45/aa12762-09/aa12762-09.html) which say that dark energy increases the potential energy in a system of a quasi-stationary gravitationally bound many-body system.

It also says that because of this, the virial mass estimate also increases with dark energy.

And likewise in this other paper (https://arxiv.org/abs/2306.14963) it is said that the presence of a cosmological constant (dark energy) increases the estimate of the mass of the Local Group. Is this because of an increase in the potential energy (as in the previous case)?

Does dark energy increase mass estimates by contributing to the potential energy of the system?

Improve this question
$\endgroup$

1 Answer 1

Reset to default
1
$\begingroup$

The mass of a system is gravitationally attractive. Dark energy is gravitationally repulsive. Thus they have opposite influences on the observable kinematics of systems of galaxies. If a system is more massive, its constituents orbit (or infall) faster. If the density of dark energy is higher, systems' constituents orbit (or infall) slower (as I discussed in a recent answer).

The idea in the papers that you link is that the kinematics of the systems under consideration are observationally constrained, and the combination of the system's mass and the dark energy density must respect that constraint. Since dark energy and mass have opposite influences, if the density of dark energy is higher, then the mass of each system must also be higher to compensate.

Improve this answer
$\endgroup$
3
  • $\begingroup$ Can this also be verified by some calculations? In other words, simulate the process? And compare with experimental data (if available)? $\endgroup$
    – dtn
    Sep 29 at 4:13
  • $\begingroup$ @dtn That's basically what arxiv.org/abs/2306.14963 (linked in the question) is doing. There are mass estimates for the Milky Way (MW) and Andromeda (M31) from the orbits of satellite galaxies, which are much closer to their hosts than the MW-M31 separation, and so are not significantly affected by dark energy. But the MW-M31 relative motion would be significantly affected by dark energy, and we also have measurements of it, so it can tell us how much dark energy there is. (See the paper for calculations -- or were you asking if I could include some example calculations?) $\endgroup$
    – Sten
    Sep 29 at 4:26
  • $\begingroup$ No, examples are not needed, I already looked at them in the article. $\endgroup$
    – dtn
    Sep 29 at 8:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.