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Cosmology researchers study the nature and evolution of the early universe. This is done by observing the Cosmic Background Microwave spectrum, investigating methods for gravitational lensing, and developing new types of instruments to study matter up to 15 billion light years away.
Cosmology researchers at JPL is developing the advanced technologies such as new detector technology new instruments and new concepts for future astrophysical space missions. These facilities would provide new capabilities to conduct sensitive astronomical observations and gather a broad range of information in all areas including photometry, polarization and spectroscopy. The Cosmology group also develops analysis tools to study the rich and diverse set of astrophysical data obtained with a number of ground-based and space telescopes, from the South Pole, Antarctica, to the Atacama Desert mountain tops in Chile and to Mauna Kea in Hawaii, as well as to the NASA space observatories, including Hubble and Spitzer.
A brief history of the universe. A representation of the evolution of the universe over 13.7 billion years. The far left depicts the earliest moment we can now probe, when a period of "inflation" produced a burst of exponential growth in the universe. The afterglow light seen by WMAP was emitted about 380,000 years after inflation and has traversed the universe largely unimpeded since then. The conditions of earlier times are imprinted on this light; it also forms a backlight for later developments of the universe. (Credit: NASA / WMAP Science Team)
The new Transition Edge Sensor (TES) antenna coupled array, designed for 150 GHz. The large format array consists of 512 pixels, each is readout by a SQUID multiplex.
The Cosmic Microwave Background
There is mounting evidence that the observable universe had undergone a superluminal “inflation” of a sub-nuclear volume. Within the last decade, works by Boomerang, Degree Angular Scale Interferometer (DASI), the Wilkinson Microwave Anisotropy Probe (WMAP) and other experiments have shown that the universe is indeed highly isotropic and nearly geometrically flat, two of the features predicted by the Theory of Inflation. The BOOMERanG B98 instrument is a balloon-borne telescope designed and optimized to observe the Cosmic Microwave Background (CMB) temperature anisotropies by taking advantage of high sensitivity detectors and long duration balloon flight from Antarctica. If Inflation is related to grand unification as many theorists believe, the physical process would be well beyond the reach of modern terrestrial accelerators. Fortunately, the CMB provides a powerful test of Inflation, in the form of a polarization signal produced by a background of gravitational waves left over from Inflation. This signal has unique pattern and should be at the level detectable with the next generation of instruments.
The group also is leading the effort in fabricating cryogenic detectors, both coherent and incoherent, for mm/submm applications. The devices are used by numerous experiments around the world, such as the Background Imaging of Cosmic Extragalactic Polarization (BICEP) experiment at the South Pole, Antarctica.
Rsearchers are leading the effort to fabricate cryogenic detectors, are deployed in experiments, such as the Background Imaging of Cosmic Extragalactic Polarization (BICEP) experiment at the South Pole.
Hubble Space Telescope image shows Einstein ring of one of the SLACS gravitational lenses, with the lensed background galaxy enhanced in blue.
Weak and strong gravitational lensing are phenomena that can help solve the puzzle of dark energy by mapping the expansion history of the universe and measuring the growth of structure, and even probe the very nature of dark matter. The research efforts at JPL are focused on theoretical and modeling developments, working with state of the art data from space- and ground-based observatories, and developing future space missions that would optimally use weak lensing and discover and exploit strong gravitational lenses to solve these fundamental problems. To those ends, the group is working actively with many international collaborations, including the Joint Dark Energy Mission and Supernoa Acceleration Probe (JDEM/SNAP), the European Space Agency Euclid Project (ESA/Euclid), the Sloan Lens ACS (SLACS) Survey, the Hubble Space Telescope (HST) Coordinates, Sizes, Magnitudes, Orientations, and Shapes (COSMOS) Survey, and more.
Dusty Galaxies and the Interstellar Medium
The group is developing new instruments to study the properties of the matter between stars in galaxies throughout their history. Stars and active galactic nuclei (AGN) are fueled by this interstellar medium. The primordial hydrogen gas appears to have been enriched with heavy elements as the first, very massive stars formed. With the carbon, oxygen, nitrogen, and silicon elements came dust, which blocks optical and near-IR radiation. The result is that for much of the history of galaxies, the birth of stars and AGN from the interstellar gas is hidden to short-wavelength observations. Fortunately, there is a rich set of spectroscopic tools available in the mid-IR through submillimeter regions which can probe the conditions in these regions. The group is developing the instruments to make these spectral measurements, with an emphasis on the best possible sensitivity and wide bandwidth to provide multiple lines and observe galaxies with unknown redshifts.
In particular, work focuses on a sensitive grating spectrometer for the Japanese Space Infrared Telescope for Cosmology and Astrophysics (SPICA) mission. SPICA is a 3.5-meter telescope actively cooled to below 5 degrees Kelvin. The very low-background platform is especially compelling for moderate-resolution extragalactic spectroscopy. The group’s proposed instrument, called Beamline Instrument Software Support (BLISS), would provide a new capability for survey spectroscopy of the galaxies, which produced the cosmic far-IR background and gave rise to our modern universe. The far-IR fine-structure and molecular are immune to dust extinction, and would unambiguously reveal these galaxies' redshifts, stellar and AGN content, gas properties and metallicites - in aggregate, the history of these dusty galaxies.