Skip to main content
We gratefully acknowledge support from the Simons Foundation, member institutions, and all contributors. Donate
arXiv logo
Cornell University Logo

Astrophysics > High Energy Astrophysical Phenomena

arXiv:2508.18126 (astro-ph)
[Submitted on 25 Aug 2025 (v1), last revised 8 Dec 2025 (this version, v2)]

Title:Inferring Mbh-Mbulge Evolution from the Gravitational Wave Background

Authors:Cayenne Matt, Kayhan Gultekin, Luke Kelley, Laura Blecha, Joseph Simon, Gabriella Agazie, Akash Anumarlapudi, Anne Archibald, Zaven Arzoumanian, Jeremy Baier, Paul Baker, Bence Bécsy, Adam Brazier, Paul Brook, Sarah Burke-Spolaor, Rand Burnette, Robin Case, James Casey-Clyde, Maria Charisi, Shami Chatterjee, Tyler Cohen, James Cordes, Neil Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan DeCesar, Paul Demorest, Heling Deng, Lankeswar Dey, Timothy Dolch, Elizabeth Ferrara, William Fiore, Emmanuel Fonseca, Gabriel Freedman, Emiko Gardiner, Nate Garver-Daniels, Peter Gentile, Kyle Gersbach, Joseph Glaser, Deborah Good, C. Harris, Jeffrey Hazboun, Ross Jennings, Aaron Johnson, Megan Jones, David Kaplan, Matthew Kerr, Joey Key, Nima Laal, Michael Lam, William Lamb, Bjorn Larsen, T. Lazio, Natalia Lewandowska, Tingting Liu, Duncan Lorimer, Jing Luo, Ryan Lynch, Chung-Pei Ma, Dustin Madison, Alexander McEwen, James McKee, Maura McLaughlin, Natasha McMann, Bradley Meyers, Patrick Meyers, Chiara Mingarelli, Andrea Mitridate, Cherry Ng, David Nice, Stella Ocker, Ken Olum, Timothy Pennucci, Benetge Perera, Polina Petrov, Nihan Pol, Henri Radovan, Scott Ransom, Paul Ray, Joseph Romano, Jessie Runnoe, Alexander Saffer, Shashwat Sardesai, A. Schmiedekamp, Carl Schmiedekamp, Kai Schmitz, Brent Shapiro-Albert, Xavier Siemens, Sophia Sosa Fiscella, Ingrid Stairs, Daniel Stinebring, Kevin Stovall, Abhimanyu Susobhanan, Joseph Swiggum, Jacob Taylor, Stephen Taylor, Mercedes Thompson, Jacob Turner, Michele Vallisneri et al. (7 additional authors not shown)  You must enable JavaScript to view entire author list.
View PDF HTML (experimental)
Abstract:We test the impact of an evolving supermassive black hole (SMBH) mass scaling relation (Mbh-Mbulge) on the predictions for the gravitational wave background (GWB). The observed GWB amplitude is 2-3 times higher than predicted by astrophysically informed models which suggests the need to revise the assumptions in those models. We compare a semi-analytic model's ability to reproduce the observed GWB spectrum with a static versus evolving-amplitude Mbh-Mbulge relation. We additionally consider the influence of the choice of galaxy stellar mass function on the modeled GWB spectra. Our models are able to reproduce the GWB amplitude with either a large number density of massive galaxies or a positively evolving Mbh-Mbulge amplitude (i.e., the Mbh / Mbulge ratio was higher in the past). If we assume that the Mbh-Mbulge amplitude does not evolve, our models require a galaxy stellar mass function that implies an undetected population of massive galaxies (Mstellar > 10^11 Msun at z > 1). When the Mbh-Mbulge amplitude is allowed to evolve, we can model the GWB spectrum with all fiducial values and an Mbh-Mbulge amplitude that evolves as alpha(z) = alpha_0 (1 + z)^(1.04 +/- 0.5).
Comments: Accepted for publication in ApJ
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2508.18126 [astro-ph.HE]
  (or arXiv:2508.18126v2 [astro-ph.HE] for this version)
  https://doi.org/10.48550/arXiv.2508.18126
Journal reference: Astrophys. J. 997, 188 (2026)
Related DOI: https://doi.org/10.3847/1538-4357/ae2480

Submission history

From: Cayenne Matt [view email]
[v1] Mon, 25 Aug 2025 15:34:10 UTC (6,225 KB)
[v2] Mon, 8 Dec 2025 19:00:33 UTC (2,610 KB)
Full-text links:

Access Paper:

view license

Additional Features

Current browse context:
astro-ph.HE
< prev   |   next >
new | recent | 2025-08
Change to browse by:
astro-ph
astro-ph.GA

References & Citations

export BibTeX citation

Bookmark

BibSonomy logo Reddit logo

Bibliographic and Citation Tools

Bibliographic Explorer (What is the Explorer?)
Connected Papers (What is Connected Papers?)
Litmaps (What is Litmaps?)
scite Smart Citations (What are Smart Citations?)

Code, Data and Media Associated with this Article

alphaXiv (What is alphaXiv?)
CatalyzeX Code Finder for Papers (What is CatalyzeX?)
DagsHub (What is DagsHub?)
Gotit.pub (What is GotitPub?)
Hugging Face (What is Huggingface?)
Papers with Code (What is Papers with Code?)
ScienceCast (What is ScienceCast?)

Demos

Replicate (What is Replicate?)
Hugging Face Spaces (What is Spaces?)
TXYZ.AI (What is TXYZ.AI?)

Recommenders and Search Tools

Influence Flower (What are Influence Flowers?)
CORE Recommender (What is CORE?)
IArxiv Recommender (What is IArxiv?)

arXivLabs: experimental projects with community collaborators

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs.

Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)