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Even if you knew nothing about astronomy, you\u2019d understand that exploding stars are forceful and consequential events. How could they not be? Supernovae play a pivotal role in the Universe with their energetic, destructive demises.<\/p>\n
There are different types of supernovae exploding throughout the Universe, with different progenitors and different remnants. The Zwicky Transient Facility has detected 100,000 supernovae and classified 10,000 of them.<\/p>\n
<\/p>\n The Zwicky Transient Facility (ZTF) is a wide-field astronomical survey named after the prolific Swiss astronomer Fritz Zwicky. In the early 1930s, Zwicky and his colleague Walter Baade coined the term \u2018supernova\u2019 to describe the transition of normal main sequence stars into neutron stars. In the 1940s, Zwicky and his colleague developed the modern supernova classification system. The ZTF bears his name because of these and many other scientific contributions. (Zwicky was also a humanitarian and a philosopher.)<\/p>\n The ZTF observes in both optical and infrared and was built to detect transients with the Samuel Oschin Telescope\u00a0at\u00a0the Palomar Observatory\u00a0in\u00a0San Diego County, California. Transients are objects that change brightness rapidly or objects that move. While supernovae (SN) don\u2019t move, they definitely change brightness rapidly. They can outshine their entire host galaxy for months.<\/p>\n In 2017, the ZTF began its Bright Transient Survey (BTS), an effort dedicated to the search for supernovae (SNe). It\u2019s by far the largest spectroscopic SNe survey ever conducted. The BTS has discovered 100,000 potential SNe, and more than 10,000 of them have been confirmed and classified according to distance, type, rarity, and brightness. These types of astronomical surveys create a rich dataset that will aid researchers well into the future.<\/p>\n \u201cThere are trillions of stars in the universe, and about every second, one of them explodes. Reaching 10,000 classifications is amazing, but what we truly should celebrate is the incredible progress we have made in our ability to browse the universe for transients, or objects that change in the sky, and the science our rich data will enable,\u201d said Christoffer Fremling, a staff astronomer at Caltech. Fremling leads the ZTF\u2019s Bright Transient Survey (BTS).<\/p>\n The effort to catalogue supernovae dates back to 2012 when astronomical databases began officially tracking them. Since then, astronomers have detected nearly 16,000 of them, and the ZTF is responsible for more than 10,000 of those detections. <\/p>\n The first documented SNe discovery was in 185 AD when Chinese astronomers recorded the appearance of a \u2018guest star\u2019 in the sky that shone for eight months. In the nearly two millennia since then, we\u2019ve seen many more. 1987 was a watershed year for supernovae science when a massive star exploded in the nearby Large Magellanic Cloud. Named SN 1987A. it was the first supernova explosion since the telescope was invented. This was also the first direct detection of neutrinos from a supernova, and the detection is considered by many to be the beginning of neutrino astronomy. <\/p>\n Each night, the ZTF detects hundreds of thousands of events, including everything from small, simple asteroids in our inner Solar System to powerful gamma-ray bursts in the distant Universe. The ZTF uses a pair of telescopes that act as a kind of \u2018triage\u2019 facility for supernovae and transients. The Samuel Oschin Telescope has a 60-megapixel wide field camera that images the visible sky every two nights. Astronomers detect new transient events by subtracting images of the same portion of the sky from subsequent scans. <\/p>\n Then, members of the ZTF team study these images and send the most promising to the other ZTF telescope, the Spectral Energy Distribution Machine (SEDM). This robotic spectrograph operates on the Palomar 60-inch telescope. <\/p>\n \u201cWe combine the brightness information from the ZTF camera with the data from the SEDM to correctly identify the origin and type of a transient, a process astronomers call transient classification,\u201d said Yu-Jing Qin, a postdoc at Caltech, who is running much of the daily operations of the BTS survey. <\/p>\n \n