- Galaxy Zoo Supernovae is a
project
- ...just like
project
Galaxy Zoo's partner in this hunt are the Palomar Transient Factory. The mission of the PTF is to look for anything that's changing in the sky — whether it's the flaring of a variable star, an asteroid moving across the sky, the flickering of an active galaxy's nucleus or a supernova. Although for now we're concentrating on finding supernovae, if all goes well then future projects may involve Zooites in chasing all of these.
The dome housing their telescope is up there in the top left of the banner. Built in the 1940s, the Samuel Oschin 1.2 m telescope is most famous for completing the massive Palomar Sky Survey, mapping the entire northern sky in unprecedented detail. The telescope is now completely automated, refurbished with a digital camera, and spends 80% of its time on PTF work. For the supernova search, it returns to the same galaxies twice a night, every five nights, searching for new objects.
Your task is to search through the candidates found by PTF. Once your results are in, PTF will organise observations on various telescopes around the world to follow up the best of our discoveries. These facilities include the 4.2m William Herschel Telescope at the Roque de los Muchachos Observatory on the Canary Island of La Palma, the Shane 3m telescope at the Lick observatory, the 5.1m Palomar Hale telescope in Southern California, and, on occasion, the mighty 10m twin Keck telescopes on the Big Island of Hawai'i. As astronomers follow-up our discoveries, they'll keep us up to date on the galaxy zoo blogs and forum.
All of these telescopes have played major roles in scientific discovery, and competition for time on these facilities is fierce. The Keck telescopes, which started science operations in 1993 and 1996, are the largest in the world, responsible for scientific breakthroughs on topics from galaxies at the edge of the universe to discovering planets around nearby stars. The Hale telescope, observing since 1948 and the largest for much of the 20th century before Keck, has a similarly prestigious history. The WHT, in its distinctive onion shaped dome, saw first light in 1987. Its most famous discovery came in 1997, when it was the first telescope to image the optical counterpart to a dramatic explosion called a gamma-ray burst. It's played a role in Galaxy Zoo history too, taking spectra of our flagship object, Hanny's Voorwerp.
Our quarry forthe hunt are supernovae; exploding stars at the end of their lives. Although caused by a single stellar system, the brightness of a single supernova can easily outshine the rest of its host galaxy. These enormous outbursts then fade slowly over the course of a month or two.
Most supernovae are caused by the collapse of massive stars which have come to the end of their lives. A small star like the Sun will fade with not a bang but a whimper as it runs out of fuel to power the nuclear fusion at its core, but stars with a mass several times that of the sun will have a more dramatic ending. Their core will collapse, producing a supernova explosion — these events are called core collapse supernovae.
Another class of supernova explosion are known as a 'Type Ia' supernovae. These form in binary systems, where the dead ember of a smaller star — a white dwarf — is close enough to pull material from a companion. This material will build up on and around the white dwarf until a critical mass is reached, resulting in a runaway nuclear fusion reaction and an enormous explosion. These supernovae are particularly interesting because they always have roughly the same luminosity. Knowing the luminosity and observing how bright the supernova appears in the sky gives us an estimate of distance, and that in turn helps us learn about the expansion of the Universe.
As our supernova hunt matures, we will add other science goals to the line-up, trying to identify other types of variable objects.