Eric Persson

Staff Member Emeritus

Observatories
email: 
persson@carnegiescience.edu

Eric Persson heads a group that develops and uses telescope instrumentation to exploit new near-infrared (IR) imaging array detectors. The team built a wide-field survey camera for the du Pont 2.5-meter telescope at Las Campanas, and the first of two cameras for the Baade telescope. Magellan consortium astronomers use the Baade camera for various IR-imaging projects, while his group focuses on distant galaxies and supernovae.

Until recently, it was difficult to find large numbers of galaxies at near-IR wavelengths. But significant advances in the size of IR detector arrays have allowed the Persson group to survey one-square degree of sky. They find and measure thousands of these objects’ brightness, estimate their distances and intrinsic luminosities, and examine the way they cluster. The group is developing another camera with a focal plane IR detector array 25 times more powerful than that of the present camera. It will be able to survey with unprecedented depth and area.

Serendipitously, Persson’s group (and others) found distant galaxies that emit virtually all of their energy in the infrared. These objects are so rare that enormous areas of sky must be studied to find them. Preliminary evidence suggests they are a varied population: most seem to be passively evolving objects in which star formation stopped several billion years ago, while some appear to have intense star formation within optically opaque dust clouds.

Persson and collaborators also study the distance-scale of the universe using newly found type Ia supernovae—exploding stars that may provide the key to reconcile the timescale, geometry, and mass content of the universe within the framework of general relativity. These supernovae events appear to have a well-defined brightness and as they rise to maximum luminosity and decline, and equivalent luminosity at maximum, which can be used to determine relative distances. To ascertain that local and distant supernovae are physically equivalent, the scientists are looking at their light variation over time at near-infrared wavelengths. This work is used to calibrate their distances and it is overcoming systematic effects that hamper optical observations.

Education: 

B.Sc. (physics), 1966, McGill University; Ph.D. (astronomy), 1972, California Institute of Technology

Interests: 
Exploring the universe with infrared detectors