BibTex format
@article{Matt:2026:1538-4357/ae801e,
author = {Matt, C and Gültekin, K and Agazie, G and Agarwal, N and Anumarlapudi, A and Archibald, AM and Arzoumanian, Z and Baier, JG and Baker, PT and Bécsy, B and Blecha, L and Brazier, A and Brook, PR and Burke-Spolaor, S and Burnette, R and Case, R and Casey-Clyde, JA and Charisi, M and Chatterjee, S and Cohen, T and Cordes, JM and Cornish, NJ and Crawford, F and Cromartie, HT and Crowter, K and DeCesar, ME and Demorest, PB and Deng, H and Dey, L and Dolch, T and Doskoch, GM and Ferrara, EC and Fiore, W and Fonseca, E and Freedman, GE and Gardiner, EC and Garver-Daniels, N and Gentile, PA and Gersbach, KA and Glaser, J and Good, DC and Harris, CJ and Hazboun, JS and Jennings, RJ and Johnson, AD and Jones, ML and Kaplan, DL and Sreekumar, AK and Kelley, LZ and Kerr, M and Key, JS and Laal, N and Lam, MT and Lamb, WG and Larsen, B and Lazio, TJW and Lewandowska, N and Liu, T and Lorimer, DR and Luo, J and Lynch, RS and Ma, CP and Madison, DR and Martsen, A and McEwen, A and McKee, JW and McLau},
doi = {1538-4357/ae801e},
journal = {Astrophysical Journal},
title = {Gravitational-wave Measurement of the MBH–Mbulge Intrinsic Scatter at High Redshift},
url = {http://dx.doi.org/10.3847/1538-4357/ae801e},
volume = {1006},
year = {2026}
}
RIS format (EndNote, RefMan)
TY - JOUR
AB - The observed gravitational-wave background (GWB) spectrum is higher in amplitude than model predictions by a factor of 2–3. Using a semi-analytic model, we evaluate the effect of a high-scatter supermassive black hole (SMBH) scaling relation (M<inf>BH</inf>–M<inf>bulge</inf>) on models of the nanohertz GWB. By implementing an intrinsic scatter of the M<inf>BH</inf>–M<inf>bulge</inf> relation, which is larger at higher redshift, but matches local observations, we find that the amplitude of GWB models increases to be consistent with the low-frequency end of the GWB spectrum. This amplitude increase is not uniform across frequencies, a strongly evolving scatter preferentially increases the number density of the most massive SMBHs which, in the GWB spectrum, minimizes the strength of the low-frequency turnover. Our models with positively evolving intrinsic scatter can reproduce the electromagnetically observed overmassive SMBHs at 4 < z < 6 without changing the M<inf>BH</inf>–M<inf>bulge</inf> normalization though we find that including moderate normalization evolution marginally improves fits to the GWB data. We conclude that the M<inf>BH</inf>–M<inf>bulge</inf> relation which best describes the available GWB and electromagnetic data sets has intrinsic scatter that evolves as (Formula presented) ε(z)=ε0+(0.56±0.4)log10(1+z) and normalization that evolves as α(z) = α<inf>0</inf>(1 + z)<sup>0.84±0.35</sup>. The results of this work imply that the M<inf>BH</inf>–M<inf>bulge</inf> relation we see today is not universal throughout cosmic time and that a diversity of seeding models and growth mechanisms may be at play in the early stages of SMBH–galaxy evolution.
AU - Matt,C
AU - Gültekin,K
AU - Agazie,G
AU - Agarwal,N
AU - Anumarlapudi,A
AU - Archibald,AM
AU - Arzoumanian,Z
AU - Baier,JG
AU - Baker,PT
AU - Bécsy,B
AU - Blecha,L
AU - Brazier,A
AU - Brook,PR
AU - Burke-Spolaor,S
AU - Burnette,R
AU - Case,R
AU - Casey-Clyde,JA
AU - Charisi,M
AU - Chatterjee,S
AU - Cohen,T
AU - Cordes,JM
AU - Cornish,NJ
AU - Crawford,F
AU - Cromartie,HT
AU - Crowter,K
AU - DeCesar,ME
AU - Demorest,PB
AU - Deng,H
AU - Dey,L
AU - Dolch,T
AU - Doskoch,GM
AU - Ferrara,EC
AU - Fiore,W
AU - Fonseca,E
AU - Freedman,GE
AU - Gardiner,EC
AU - Garver-Daniels,N
AU - Gentile,PA
AU - Gersbach,KA
AU - Glaser,J
AU - Good,DC
AU - Harris,CJ
AU - Hazboun,JS
AU - Jennings,RJ
AU - Johnson,AD
AU - Jones,ML
AU - Kaplan,DL
AU - Sreekumar,AK
AU - Kelley,LZ
AU - Kerr,M
AU - Key,JS
AU - Laal,N
AU - Lam,MT
AU - Lamb,WG
AU - Larsen,B
AU - Lazio,TJW
AU - Lewandowska,N
AU - Liu,T
AU - Lorimer,DR
AU - Luo,J
AU - Lynch,RS
AU - Ma,CP
AU - Madison,DR
AU - Martsen,A
AU - McEwen,A
AU - McKee,JW
AU - McLaughlin,MA
AU - McMann,N
AU - Meyers,BW
AU - Meyers,PM
AU - Mingarelli,CMF
AU - Mitridate,A
AU - Ng,C
AU - Nice,DJ
AU - Nichols,S
AU - Ocker,SK
AU - Olum,KD
AU - Pennucci,TT
AU - Perera,BBP
AU - Petrov,P
AU - Pol,NS
AU - Radovan,HA
AU - Ransom,SM
AU - Ray,PS
AU - Romano,JD
AU - Runnoe,JC
AU - Saffer,A
AU - Sardesai,SC
AU - Schmiedekamp,A
AU - Schmiedekamp,C
AU - Schmitz,K
AU - Shapiro-Albert,BJ
AU - Siemens,X
AU - Simon,J
AU - Fiscella,SVS
AU - Stairs,IH
AU - Stinebring,DR
AU - Stovall,K
AU - Susobhanan,A
AU - Swiggum,JK
DO - 1538-4357/ae801e
PY - 2026///
SN - 0004-637X
TI - Gravitational-wave Measurement of the MBH–Mbulge Intrinsic Scatter at High Redshift
T2 - Astrophysical Journal
UR - http://dx.doi.org/10.3847/1538-4357/ae801e
VL - 1006
ER -