For NYSS APS information, contact:
Dr. Erica Simoson 

"Monsters on the move: Gravitational wave recoiling supermassive black hole candidates"

Yashashree Jadhav, RIT

There is compelling evidence that supermassive SMBH (SMBH) reside at
the centers of all large galaxies and are the gravitational ‘engines’ of Active Galactic Nuclei (AGN). Mergers between galaxies are thought to have played a fundamental role in the growth and evolution of the largest galaxies in the nearby universe. A galaxy merger leads to the formation of an SMBH binary, which eventually coalescences through the emission of gravitational waves and receives a gravitational recoil kick (up to several 1000km/s). This recoil in turn causes the merged SMBH to oscillate (up to ~1 Gyr) in the gravitational potential well of the galaxy. During this time, the recoiling SMBH may be observed as a ‘displaced’ AGN. These events are a strong test of gravitational physics and merger frequency of binary SMBH. Recoiling SMBH can be detected via electromagnetic signatures. As a result of residual oscillations, displacements ~10 – 100pc may be expected even in nearby elliptical galaxies and can be measured as spatial offsets of AGN in high resolution optical or infrared images. In a preliminary study, isophotal analysis was conducted on a sample of 96 galaxies to obtain the photocenter of the galaxies using mostly Hubble Space Telescope (HST) archival images (mostly in the visual filters). The position of the nuclear point source (AGN) was also measured to obtain a displacement vector. Analysis of this initial sample reveals 18 candidates that show a significant displacement. Of these, 14 are hosted by core ellipticals while the rest have a cuspy light profile. A majority of the galaxies analyzed have galactic and nuclear dust structures that interfere with the isophotal analysis. We will also present preliminary results from new HST infrared images (in filters F110W and F160W) of 2 of the 18 candidates.

For program, contact:  
Dr. Heather Watson – watsonh@union.edu
Dr. Nelia Mann – mannn@union.edu
Dr. Samuel Amanuel – amanuels@union.edu
Ms. Lynnette Stec – stecl@union.edu
Phone: 518-388-6254
Fax: 518-388-6947
Department of Physics & Astronomy, Union College, Schenectady, NY 12308