Research Highlights

Aug 16, 2017 | On the trail of dark matter with LUX-ZEPLIN

Based on a press release from the SLAC Office of Communications

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory, including several KIPAC scientists, are on a quest to solve one of physics’ biggest mysteries: What exactly is dark matter—the invisible substance that accounts for 85 percent of all the matter in the universe but can’t be seen even with our most advanced scientific instruments?

Aug 4, 2017 | Standard model of the universe withstands most precise test by Dark Energy Survey

Astrophysicists have a fairly accurate understanding of how the Universe ages: That’s the conclusion of new results from the Dark Energy Survey (DES), a large international science collaboration, including researchers from the Department of Energy’s SLAC National Accelerator Laboratory, that put models of cosmic structure formation and evolution to the most precise test yet.

Jul 5, 2017 | The first galaxies could really mix it up!

An international team of researchers, most of whom have ties to KIPAC, has shown that the hot diffuse gas that fills the space between the galaxies has the same concentration of iron in all galaxy clusters that were studied in sufficient detail by the Japanese Suzaku satellite.

An international team of researchers, most of whom have ties to KIPAC, has shown that the hot diffuse gas that fills the space between the galaxies has the same concentration of iron in all galaxy clusters that were studied in sufficient detail by the Japanese Suzaku satellite.

These results confirm the team's earlier findings regarding the Perseus Cluster, published in Nature, which suggested that most of the iron in the Universe was produced and spread throughout intergalactic space before galaxy clusters formed, more than 10 billion years ago. The iron, along with many other elements, was blown out of galaxies by the combined energy of billions of supernovae, as well as outbursts from growing supermassive black holes.

Jun 16, 2017 | Gigantic X-rays flares offer new insight into the whirling maelstrom just outside supermassive black holes

Supermassive black holes power some of the most luminous objects we see in the Universe. When material spirals into a supermassive black hole in the center of a galaxy that is in excess of a million Solar masses, it gives rise to an active galactic nucleus, or AGN (also discussed in two previous KIPAC blogposts: this one focused on observations of flaring from AGNs, whilethis one focused on simulation aspects). In addition to spewing electromagnetic radiation running from visible light through ultraviolet all the way to X-rays and gamma rays, many AGN can launch jets of particles at close to the speed of light. These jets are detected through the radio waves they emit by synchrotron radiation and can extend between 50 and 100 kpc (about 150,000 to 300,000 light years) from the central black hole. All this activity occurs in and around the so-called accretion disc: the flattened disc of gas that is spiralling into the black hole, just moments before it plunges through the surface of no return, the “event horizon” of the central massive black hole.

May 3, 2017 | They blinded it for science

Scientific introspection is necessary because of a known unknown in the world of experimentation called experimenter bias, the name given to all the ways in which simply being human can affect how scientists take data, analyze data, and interpret data. “Experimenter bias” is a known—i.e. it is well-known to exist—but it’s also unknown, because the psychology of the human scientist can’t be easily quantified. Researchers can’t add error bars indicating the strength of a preconceived notion or the weight of an unconscious desire, yet subtle and not-so-subtle influences definitely exist, such as the result of a previous experiment or the conclusion of a popular theory, and these influences can nudge a researcher into accepting a result prematurely or discounting results that don’t conform to expectation.

Apr 6, 2017 | SPT-3G deployment: Going to the ends of the Earth to capture pictures of the infant universe

Last December, I travelled to the southernmost tip of the Earth to install a new camera on the South Pole Telescope (following a rich tradition of other KIPAC researchers who have travelled to Antarctica and returned to write about it, e.g. Val Monticue and Albert Wandui). This blogpost brings you along for a bit of that journey!

Mar 8, 2017 | Seeing is believing: “Observing” simulations of relativistic jets

The high-energy universe is a fascinating place to observe: giant stars explode into supernovae, briefly outshining their own galaxies; pulsars with more mass than our Sun but only twelve miles across spin hundreds of times each second; and supermassive black holes at the centers of galaxies can suck dust and gas into accretion disks and blast this material in plasma form back out in powerful relativistic jets spewed out at close to the speed of light.

Mar 1, 2017 | Latest measure of cosmic expansion hints that Universe is growing faster than expected

The H0LiCOW collaboration just released news that they’ve measured what KIPAC and H0LiCOW collaboration member Phil Marshall calls “a key property of the universe”: the Hubble constant, which tells how fast the universe is expanding.  According to their measurements, our universe is currently expanding at 71.9 km/s/Mpc, within about 3.8% accuracy, which means that each second, our universe is adding very close to 71.9 kilometers of space per megaparsec in every direction. This expansion is increasing, a phenomenon attributed (for now, at least) to the influence of a new component of the universe, dark energy.

Dec 19, 2016 | The Devil is in the Details: What Galaxy Dynamics Can Tell Us About Dark Matter

The acronym ΛCDM (Lambda-cold dark matter) is shorthand for our current best cosmological model describing the early beginnings, evolution until now, and future development of our entire Universe. It posits a cosmos dominated by a cosmological constant (denoted by Λ, the Greek letter capital lambda) our best guess for the phenomenon of dark energy, and a type of slow-moving, non-interactive matter called cold dark matter that outweighs the ordinary matter making up stars and planets—and us—by more than five to one. ΛCDM does well enough explaining the majority of our astrophysical observations that it is the standard paradigm for most people working in the field.

Nov 8, 2016 | What these students did for their summer vacation: 2016 undergraduate research at KIPAC!

Some things just go together. Hot dogs and mustard, smart phones and selfies, school and summer vacation. But science is a year-round proposition, and several undergrads didn't seem to mind forgoing their summer vacations to pursue a variety of research opportunities with members of KIPAC. (Protip: it’s never too soon to start thinking about next summer!)

Oct 18, 2016 | Using Gravitational Lensing to Hunt for Hidden Knots of Dark Matter

By modeling the warped images of a gravitational lens observed with one of the most powerful telescopes in the world, KIPAC scientists have made the dramatic discovery that there is a clump of dark matter with no currently visible normal-matter counterpart in a far-away galaxy. Such unaccompanied clumps are incredibly difficult to detect and only a small handful of them have ever been discovered, but a concerted effort to find them and determine how and why they form could pay off significantly in the long term by giving us new insights as to the nature of dark matter.

Sep 25, 2016 | Searching for gamma-ray needles in a gravitational wave haystack with Fermi/LAT

The first direct detection in 2015 of a gravitational wave event (GW) by the recently upgraded Laser Interferometer Gravitational-Wave Observatory, known as Advanced LIGO, ushered in with a mighty bang a completely new era in astronomy. The first science run with the Advanced LIGO detector started in September 2015, and two high-significance events (GW150914 and GW151226) and one sub-threshold event (LVT151012) were reported. These three events were compatible with signals expected from the mergers of two black holes.