Weighing GalaxiesManoa's Adam Bolton make a discovery in the relationship between galaxy mass and luminosity. Read moreDark Energy EvidenceManoa’s Istvan Szapudi, Mark Neyrinck and Benjamin Granett image dark energy in action. Read more
Astrochemistry GrantThe W.M. Keck Foundation supports research into the chemical evolution of the solar system. Read more
KudosManoa’s Maile Andrade, Matthew Craig, C Manu Kaiama, Lilikala Kame'eleihiwa, Karen Kosasa, Geoff White and Vicky Holt Takamine and Hilo’s Robert Fox. Read more
BOR ReportPeter Quigley appointed interim vice chancellor and Hawai'i’s hospitality and tourism degree status established. Read moreMark Twain’s Early ReportingManoa’s James Caron publishes Mark Twain, Unsanctified Newspaper Reporter. Read more
UH EventsManoa’s Hawai‘i Institute for Contemporary Music, Hilo’s chocolate tasting event and more. Read more
Hubble Space Telescope image shows Einstein ring of one of the SLACS gravitational lenses, with the lensed background galaxy enhanced in blue. Image by A. Bolton (UH/IfA).
Weighing Galaxies
An international team of astronomers, including Manoa Beatrice Watson Parent Postdoc Adam S. Bolton made a discovery that helps to settle a long-standing debate over the relationship between mass and luminosity in galaxies.
The team achieved this result by compiling the largest-ever single collection of “gravitational lens” galaxies—70 in all. A gravitational lens is a phenomenon similar to a terrestrial mirage, but it occurs on a scale of many thousands of light-years. When two galaxies happen to be precisely aligned with one another in the sky, the gravitational field of the nearer galaxy distorts the image of the more distant galaxy into multiple arc-shaped images or even into a complete ring, known as an Einstein ring. These Einstein ring images can be up to 30 times brighter than the image of the distant galaxy would be in the absence of the lensing effect.
“The SLACS collection of lenses is especially powerful for science,” says Bolton, lead author of two papers describing these latest results, which will be published in the Astrophysical Journal. “For each lens, we measured the apparent sizes of the Einstein rings on the sky using the Hubble images, and we measured the distances to the two galaxies of the aligned pair using Sloan data. By combining these measurements, we were able to deduce the mass of the nearer galaxy.”