arXiv subjects

Maggie C. Huber

Publications and source records attributed to Maggie C. Huber.

4 recordsLinked to original sources

arXiv2026

Overmassive supermassive black holes in SDSS close galaxy pairs

Supermassive black holes (SMBHs) and their host-galaxies coevolve through channels such as hierarchical merging and AGN feedback, establishing tight scaling relations between SMBH masses and properties of the host-galaxy. These scaling relations, particularly those with host-galaxy bulge mass (M${_\text{b}}$) and stellar velocity dispersion ($σ$), are widely used to estimate SMBH masses. Galaxy mergers drive gas into the centers of galaxies, enhancing SMBH growth and stellar bulge growth but not necessarily in tandem, so it is necessary to determine if galaxies undergoing a merger still follow SMBH-host-galaxy scaling relations. In this study, we explore scaling relations in galaxy mergers by taking advantage of the well-established value-added catalogs in the Sloan Digital Sky Survey. These catalogs provide close galaxy pairs, AGN broad lines for SMBH mass measurements, and bulge-disk decomposed stellar masses. We compare SMBH mass estimates from M$_\bullet-$M${_\text{b}}$ to SMBH mass estimates from AGN broad lines and find that SMBH mass growth outpaces the bulge for AGN residing in the secondary (less massive) bulge and for smaller physical separations between galaxies in a pair. Using our full sample of close galaxy pairs, we find that M$_\bullet-$M${_\text{b}}$ and M$_\bullet- σ$ predict significantly different fractions of major and minor black hole mergers with M$_\bullet-$M${_\text{b}}$ predicting black hole mass ratios closer to 1:1 and $6-20\%$ more major mergers overall. These results have major implications, including for predictions of astrophysical gravitational-waves and high-redshift overmassive SMBHs.

astro-ph.GA↗

arXiv2025

The impact of applying black hole-host galaxy scaling relations to large galaxy populations

Supermassive black holes (SMBHs) with dynamically measured masses have shown empirical correlations with host galaxy properties. These correlations are often the only method available to estimate SMBH masses and gather statistics for large galaxy populations across a range of redshifts, even though the scaling relations themselves are derived from a small subset of nearby galaxies. Depending on the scaling relation used, estimated SMBH masses can vary significantly. The most widely used scaling relations are the M$_{BH}-$M$_{\mathrm{bulge}}$ and M$_{BH}- σ$ relations, where M$_{\mathrm{bulge}}$ is galaxy bulge mass and $σ$ is the bulge velocity dispersion. In this paper, we determine how severely the choice of scaling relation impacts SMBH mass estimates for different subsets of a large galaxy population. For this analysis we use a sample of $\sim$ 400,000 galaxies, including 1,240 Type 1 AGN from the Sloan Digital Sky Survey. We calculate SMBH masses from M$_{BH}-$M$_{\mathrm{bulge}}$ and M$_{BH}- σ$ and compare to single-epoch virial SMBH masses from broad-line H$β$, which are derived independently of black hole-host galaxy scaling relations. We find that SMBH masses derived from the single-epoch virial relation for H$β$ are better reproduced by M$_{BH}- σ$ than M$_{BH}-$M$_{\mathrm{bulge}}$. Finally, in cases where $σ$ and M$_{\mathrm{bulge}}$ cannot be measured directly, we show that it is possible to infer $σ$ from photometry with more accuracy than we can infer M$_{\mathrm{bulge}}$.

astro-ph.GA↗

arXiv2022

Mitigating the effects of instrumental artifacts on source localizations

Instrumental artifacts in gravitational-wave strain data can overlap with gravitational-wave detections and significantly impair the accuracy of the measured source localizations. These biases can prevent the detection of any electromagnetic counterparts to the detected gravitational wave. We present a method to mitigate the effect of instrumental artifacts on the measured source localization. This method uses inpainting techniques to remove data containing the instrumental artifact and then correcting for the data removal in the subsequent analysis of the data. We present a series of simulations using this method using a variety of signal classes and inpainting parameters which test the effectiveness of this method and identify potential limitations. We show that in the vast majority of scenarios, this method can robustly localize gravitational-wave signals even after removing portions of the data. We also demonstrate how an instrumental artifact can bias the measured source location and how this method can be used to mitigate this bias.

astro-ph.IM↗

arXiv2021

The Hosts of X-ray Absorption Lines Toward AGNs

Most baryonic matter in the universe exists in gaseous form and can be found in structures such as galactic halos and the low-density intergalactic medium. proposed-ray spectroscopy missions such as Athena, Arcus, and Lynx will have the capability to identify absorption lines in spectra toward bright active galactic nuclei (AGNs), which can be used as a tool to probe this missing matter. In this study, we examine the optical fields surrounding 15 primary observing targets and identify the foreground galaxies and galaxy groups that are potential hosts of absorption. We record the basic properties of the potential host and their angular and physical separation from the AGN line of sight. This process is done by marking the location of various galaxies and groups in optical images of the field surrounding the target and plotting their angular separation vs. redshift to gauge physical proximity to the background source. We identify the surrounding objects according to those which have measured redshifts and those that require them.

astro-ph.GA↗