Some of the brightest objects in the sky are called blazars. They consist of a supermassive black hole feeding off material swirling around it in a disk, which can create two powerful jets perpendicular to the disk on each side. A blazar is especially bright because one of its powerful jets of high-speed particles points straight at Earth. For decades, scientists have wondered: How do particles in these jets get accelerated to such high energies?
Nov 25, 2022 | IXPE helps solve black hole jet mystery
Biopolymers (large molecules operating in living systems, such as DNA or proteins) possess a unique architecture: the arrangement of their atoms in space has the property of specific chirality (or handedness; the word “chiral” comes from Greek for “hands”). How this happened is unknown and solving it is central to understanding the origin of life because the property of homochirality—where all biomolecules of a certain type have the same chirality—allows the biopolymers to adopt stable helical structures. As a result, their helices spiral in only one direction, and this direction is the same for all living organisms.
Dark matter’s stubborn resistance to discovery has forced us to reevaluate what it may look like. If it is much lighter than we’ve assumed, there must be more of it around to make up the total mass required to hold galaxies together. Our challenge: the signals these lighter particles would leave in terrestrial detectors are smaller than any we’ve ever set out to measure. To answer that challenge, DM physicists are constructing the coldest, quietest, most sensitive particle detectors ever made.
Jul 29, 2022 | The LSST Camera is ‘an experiment in an experiment'
For more than a decade, scientists and engineers from the SLAC National Accelerator Laboratory (SLAC) have been leading the development of the world’s largest digital camera for the Legacy Survey of Space and Time (LSST) Simonyi Survey Telescope. They’ve broken Guinness World Records for highest resolution digital camera and largest lens, but the heart of the camera—a table-sized focal plane made up of nearly two hundred charge-coupled devices (CCDs)—has been a scientific study in its own right, filling thousands of research papers and countless PhD dissertations.
Our Universe is believed to be filled with a chaotic sea of low-frequency gravitational waves, perturbations in space-time caused by orbiting pairs of supermassive black holes at the centers of merging galaxies. These waves can be light-years long and astronomers have been chasing them for decades using large radio telescopes around the globe. Now a powerful new tool—one with a long association to KIPAC—has been developed, and the hunt has moved to space using gamma rays, the highest-energy form of light.
Jun 28, 2022 | LSST Camera’s Unintentional World Records
In an unassuming tan building, past windswept hills and equipment from the now-defunct B-Factory particle accelerator, scientists and engineers at the SLAC National Accelerator Laboratory (SLAC) have nearly finished building the world’s largest digital camera for the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST). Construction began in 2015 and since then, the LSST camera team set a Guinness World Record for the camera’s focal plane, a table-sized array of 189 sensors working in concert to produce the highest resolution digital image ever made: 3,200 megapixels. That’s over 1500 times the resolution of a high-definition television. The team didn’t plan on breaking any world records, but to build a camera that can take thousands of images every night—each one over three billion pixels in size—they sort of had to.
Jun 16, 2022 | Exploring the Cosmos while Preserving Spaceship Earth
Extracting information from the data gathered by large cosmological surveys requires sophisticated theory modeling that combines physical models of our Universe, astrophysical models of galaxies, and telescope and survey-specific models of measurement uncertainties. The theory models involved are now quite sophisticated and typically have thirty to fifty parameters, making it hard to find plausible sets of parameters that describe the observational data. Therefore, even with the most advanced algorithms and software, analyses of modern cosmological datasets are costly, not only in the time required for computers to finish an analysis, but in energy needed to run the computers.
Celebrated physicist and Rubin Observatory project scientist Steve Kahn has crisscrossed the country multiple times during his academic career—from a PhD at University of California Berkeley to Columbia University and back west to Stanford—but his biggest leap was shifting from a decades-long career in X-ray astronomy to building the world’s largest digital camera for the Legacy Survey of Space and Time (LSST). Now he's making another big leap to Dean of the Division of Mathematical and Physical Sciences at the University of California, Berkeley.
May 2, 2022 | The telescope at the edge of the solar system
New research led by KIPAC PhD student Alex Madurowicz, published in the Astrophysical Journal, describes a novel technique to image Earth-like exoplanets in detail by using the Sun as a telescope. The gravity of the Sun lenses and magnifies light from a distant planet, but also distorts the image into what is now known as an Einstein ring. By tracing the path of light as it bends around the Sun, the Einstein ring can be deconstructed to recover an image of a distant planet. This concept would allow for observations in far greater detail than an ordinary telescope could ever possibly achieve, such as movies of the detailed surfaces of exoplanets.
Sometime this fall, the Legacy Survey of Space and Time (LSST) camera will be delivered to Santiago on a 747 jumbo jet and trucked to the Rubin Observatory Summit Facility. Located nearly nine thousand feet above sea level in the Andean foothills—about two hours from Chile’s second-oldest city, La Serena—the observatory will house an 8.4 meter (almost 28 feet!) telescope containing the largest digital camera ever built. Each night, the SUV-sized camera will collect thousands of wide-field images of the southern sky, looking further back into the history of the universe with each exposure. Commissioning engineers and scientists from the SLAC National Accelerator Laboratory (SLAC) have been developing novel ways to handle the many technical challenges that come with building a Guinness World Record breaking observatory.
In DES cosmology analyses we ultimately learn about physics by comparing the predictions of a model to measurements. Even with our most sophisticated models of the Universe, we can’t predict exactly where a given galaxy or clump of matter that is causing gravitational lensing will appear. However, we don’t need to do that to learn about physics! We just need to focus on something we can predict: the statistical properties of how we expect galaxy positions and the shear signal of weak gravitational lensing to be distributed relative to one another. This means that when we compare our model to measurements, we’re not comparing models and measurements at the level of the full map of the positions and shapes of all the galaxies measured by DES. Instead we summarize information in those maps using statistical measurements.
Understanding how the Universe evolved from a dense ball of superheated plasma to the vast canvas of stars and galaxies it is today—and what it will become next—remains a fundamental question asked throughout history. Today, we can begin to answer this question by making more precise measurements of objects in space, from our nearest neighbors to the deepest recesses of the visible Universe, than we've ever been able to before. The resulting maps help us frame the question of how the Universe unfolds by measuring how cosmic structure—the web of galaxies that make up the Universe—grows over time, according to the rules of physics. A key part of measuring this cosmic structure is to determine the distances to the many galaxies we observe with our telescopes.