Astrophysics/cosmology research

Study of supernovae

Professor David Cinabro

Supernovae are stars that explode when they reach the end of their life. For about one week a single star glows as bright as an entire galaxy of billions of stars before it fades into eternal darkness.

What is most amazing is that one class of supernova, type Ia's, produce a well-known amount of light. Thus they can be used as a distance measure. By measuring the distance to supernova as a function of time we are able to measure the expansion history of the universe. This reveals that some mysterious force, called dark energy, is pushing the universe apart towards a cold, dark, lifeless future.

Sloan Digital Sky Survey Supernova Search
Sloan Digital Sky Survey Supernova Search

The Sloan Digital Sky Survey Supernova Search uses the 2.5-meter telescope at the Apache Point Observatory in New Mexico to search for and study supernova and study cosmology. Professor Cinabro is a member of this project and has special interest in measuring the rate of type Ia supernova which reveals the history of the rate of star formation in the universe, the effects of the galaxy host on the type 1a supernova trying to answer the question if brighter supernova occur in young star-forming galaxies, and studying other sorts of supernova that arise when stars run out of fuel, collapse, and explosively rebound.

Professor Cinabro is also a member of the Large Synoptic Survey Telescope project. This is a plan to build an 8.5-meter telescope in Chile which will comprehensively survey half of the sky every other night. It will provide an incomparable sample of transient celestial phenomena, including a definitive sample of a supernova.

Study of neutron stars

Professor Edward Cackett

Neutron stars are fascinating objects. They are formed in a supernova explosion at the end of a star's life: what is left after the explosion is a tiny, incredibly dense star.

X-ray satellites observe neutron stars.
X-ray satellites observe neutron stars.

They have a mass a little more than that of our sun, yet are crammed into a sphere only about 20-30 km across. This makes the very centers of neutron stars more dense than atomic nuclei! On Earth, we cannot reproduce those conditions experimentally, which makes neutron stars a unique astrophysical laboratory to study the densest observable material in the universe. What neutron stars are made of is a vital question that underpins our knowledge of the way fundamental physics works – how does matter behave when it is compressed to such extreme densities?

Dr. Cackett uses world-leading X-ray satellites to observe neutron stars in binary systems where a star similar to the sun and a neutron star orbit each other. In such systems, the gravity of the neutron star can pull matter from the companion, which then spirals down onto the neutron star forming a hot disk of gas (an 'accretion disk') around it. Dr. Cackett studies this accretion process and its effects on the neutron star in order to learn about the nature of these superdense objects.

For more information about this research, visit the Chandra X-Ray Observatory.

Study of black holes

Professor Edward Cackett

Black holes are objects so dense that even light cannot escape their gravitational pull.  They can come in several different masses - stellar-mass black holes have masses that are typically 10 tens the mass of our Sun, and, like neutron stars, are formed in supernovae explosions at the end of a massive star's life.  Supermassive black holes, on the other hand, have masses typically between a million and a billion times the mass of the Sun and every major galaxy in the universe, including our own Milky Way, seems to have one at their center.  Astronomers still don't know exactly how they form.

Artistic interpretation of material falling onto a supermassive black hole. Credit: NASA/JPL

 

Dr. Cackett uses multiwavelength observations to investigate how material falls onto black holes.  Since the angular size of most black holes is far too small to be imaged by current technologies, indirect techniques must be used.  Dr. Cackett uses a technique called reverberation mapping that measures echoes of light to try and reconstruct the size of structure of the gas falling into black holes. He uses a range of facilities includes NASA's Hubble Space Telescope, the Neil Gehrels Swift Observatory, the NICER X-ray mission as well as Wayne State's own Dan Zowada Memorial Observatory.  In January 2019, Cackett co-authored work featured on the front cover of prestigious journal Nature - you can read a brief description here

Dan Zowada Memorial Observatory

The Dan Zowada Memorial Observatory is a state-of-the-art 20-inch robotically-controlled remote observatory in the high desert of Rodeo, NM at an altitude of 4128 feet. This location has some of the darkest skies in the nation!

The observatory is named in honor of Michigan amateur astronomer Dan Zowada, who tragically died of cancer at the age of 54.

The observatory was kindly donated to Wayne State University by the 419 Foundation of Russ and Stephanie Carroll.

Dan Zowada Memorial Observatory telescope
Dan Zowada Memorial Observatory telescope