Research
Black Holes
One of the most important findings in astrophysics is that when stars die they can collapse to extremely small objects. When their internal fuel sources are exhausted, stars millions of miles across can collapse to roughly 10 kilometers in diameter, known as neutron stars.
In extreme cases, stars can contract even further under their own gravity... Read More »
Blazars and Active Galactic Nuclei
Nature has provided us with spectacular particle accelerators called active galactic nuclei, or AGN. These are galaxies that host tremendously large black holes at their centers, some of which are known to be a million times heavier than our sun. hese distant celestial laboratories allow researchers to study physics at energies orders of magnitude... Read More »
Cosmic Microwave Background
The Cosmic Microwave Background, or CMB, is a faint glow in microwave radiation that is almost perfectly uniform across the sky. This thermal radiation was emitted about 380,000 years after the Big Bang, as the universe became transparent for the first time.
The CMB peaks at a wavelength of about 2 mm with a nearly perfect blackbody... Read More »
Dark Matter and New Physics
To better understand our universe, it is often necessary to estimate the mass of an astrophysical object. Those objects can be found across a vast range, from the size of the Sun, the solar system, the Milky Way, and even the entire universe.
Researchers use a number of techniques to measure the mass of extremely large objects. One way to... Read More »
Direct Dark Matter Detection
A leading hypothesis on the nature of Dark Matter is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors as shown in this cartoon:
To shield the... Read More »
First Cosmological Objects
The first objects to form in the Universe were stars. Some 200 million years after the big bang, the diffuse gas permeating the early Universe is able to contract under its own gravity setting the collapse to the first stars in motion. Once this collapse reaches a critical density, thermonuclear reactions will start and the star will light up as... Read More »
Galaxy Clusters
Galaxy clusters are the largest objects in the universe, spanning distances up to ten million light years, and containing the equivalent mass of a million, billion suns. Our research examines the physics of these remarkable systems using the best available multi-wavelength data, and uses the observed properties of clusters to probe the nature of... Read More »
Galaxy Formation
Galaxies are collections of stars, gas and dark matter that play host to some of the most extreme processes in nature. Galaxies are also the signposts of the universe, beacons of light scattered throughout a mostly dark universe. Though galaxies are filled with the visible “stuff” of the cosmos, they are also critical laboratories in... Read More »
Gamma-Ray Bursts
Gamma-ray bursts (GRBs) are short flashes of photons thought to originate from collapsing stars. These strong pulses have energies in the X-ray to gamma-ray ranges and time scales ranging from a few milliseconds to around 100 seconds. The separation between "short" and "long" bursts is around two seconds. Though short-lived,... Read More »
Gravitational Lensing
We cannot see one of the universe’s primary constituents: dark matter. The reason is simple: it's dark. But we can infer where it is located from observations of distant galaxies because of a key property of light, namely that it does not always travel in straight lines. For example, galaxies and clusters of galaxies deflect, or... Read More »
High Energy Particles From Space
Astronomers are popularly supposed to observe the cosmos using visible light. However, today they use the whole 70 octave electromagnetic spectrum from the longest wavelength - 20 meter - radio waves to the highest energy - 100 TeV - gamma rays. The gamma rays in particular are thought of as particles, called photons, because that is the way they... Read More »
Indirect Dark Matter Detection
Dark Matter and New Physics
The Fermi-Large Angle Telescope (Fermi-LAT) probes photons of the highest energies. At such energy scales, these particles may exhibit signatures of the new physics, which deviate significantly from the Standard Model. For instance, the currently accepted standard cosmological model predicts that the universe is... Read More »
Neutron Stars and Pulsars
Neutron Stars
A neutron star is the product of the explosive transformation of a massive star. Any star's life is a careful balancing act: the gravity of its own material pulls inward, while pressure from the heat and light produced by the burning of hydrogen into helium in the star's core pushes outward. For a massive star, this... Read More »
Optical Surveys
In the traditional model of astronomical observation, individual or small teams of astronomers will study a select class of objects in a small region of sky. However, some of the most exciting cosmological and astrophysical results in recent years have required the study of millions of galaxies over thousands of square degrees of sky. ... Read More »
Particle Acceleration
Particle Acceleration
A long-standing mystery is the mechanism by which cosmic rays are accelerated in our galaxy. While the most powerful accelerators on Earth, such as the Large Hadron Collider, can accelerate particles to teraelectronvolt, or TeV, energy scales, fluxes of cosmic rays reaching the Earth have been detected with energies up... Read More »
Primordial Inflation
The universe began in a hot big bang 13.7 billion years ago. It is remarkably homogeneous on the large scale and at the time we observe the cosmic microwave background parts that are out of contact with each other are similar at the level of about ten parts per million. How did this remarkable synchronization come about? In the early 1980s then... Read More »
Reionization
Roughly 400,000 years after the Big Bang, the universe – bathing in the afterglow of radiation that we see today as the cosmic microwave background – began to enter the cosmic “dark ages,” so named because the luminous stars and galaxies we see today had yet to form. Most of the matter in the cosmos at this stage was dark... Read More »
Relativistic Outflows
Relativistic Outflows
The Fermi-LAT detects gamma-rays with energies several hundred times the rest mass of an electron. The generation of gamma-rays with these energies requires extremely energetic particles. In some galactic sources, the radiating particles are energized by acceleration from shocks formed in the wake of stellar explosions... Read More »
Scientific Visualization and Data Analysis
As part of the Computational Physics Department, KIPAC's visualization and data analysis facilities provide hardware and software solutions that help users at KIPAC and SLAC to analyze their large-scale scientific data sets. Examples include interactive real-time 3D visualization methods for state-of-the-art numerical computational fluid... Read More »
Solar Physics - Science
Observational and theoretical research on the physics of the sun is carried out at Stanford University in several research groups. sun.stanford.edu will link you to the projects carried out by a group of scientists and supporting staff associated with the Center for Space Science and Astrophysics (CSSA) and the Hansen Exerimental Physics... Read More »