A Low-Mass Black Hole in the Nearby Seyfert Galaxy UGC 06728

• Published in: arXiv.org 2016-08
• Main Authors: Bentz, Misty C, Batiste, Merida, Seals, James, Garcia, Karen, Rachel Kuzio de Naray, Peters, Wesley, Anderson, Matthew D, Jones, Jeremy, Lester, Kathryn, Machuca, Camilo, Parks, J Robert, Pope, Crystal L, Mitchell Revalski, Roberts, Caroline A, Saylor, Dicy, Sevrinsky, R Andrew, Turner, Clay
• Format: Article
• Language: English
• Subjects: Anchors; Galaxies; Luminosity; Mapping; Seyfert galaxies; Time lag
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1608.03893

We present the results of a recent reverberation mapping campaign for UGC 06728, a nearby low-luminosity Seyfert 1 in a late-type galaxy. Nightly monitoring in the spring of 2015 allowed us to determine an H\(\beta\) time delay of \(\tau = 1.4 \pm 0.8\) days. Combined with the width of the variable H\(\beta\) line profile, we determine a black hole mass of \(M_{\rm BH} = (7.1 \pm 4.0) \times 10^5\) M\(_{\odot}\). We also constrain the bulge stellar velocity dispersion from higher-resolution long slit spectroscopy along the galaxy minor axis and find \(\sigma_{\star} = 51.6 \pm 4.9\) km s\(^{-1}\). The measurements presented here are in good agreement with both the \(R_{\rm BLR} - L\) relationship and the \(M_{\rm BH}-\sigma_{\star}\) relationship for AGNs. Combined with a previously published spin measurement, our mass determination for UGC 06728 makes it the lowest-mass black hole that has been fully characterized, and thus an important object to help anchor the low-mass end of black hole evolutionary models.