Research at IPAC
Critical to the proper execution of all programs at the Greater IPAC is a staff of active researchers who can guide the development of those tasks and subsequently assist other astronomers in using the final products. The list below is intended to highlight our research activities and provide links to resources internally and globally, in the hope of improving visibility and encouraging collaborations both within IPAC and with the science community at large.
- Mid-Infrared Properties of Nearby Luminous Infrared Galaxies I: Spitzer IRS Spectra for the GOALS Sample S.Stierwalt, L. Armus, J.A. Surace, et al.
- The Coldest Brown Dwarf (Or Free Floating Planet)?: The Y Dwarf WISE 1828+2650 Charles A. Beichman, Christoper R. Gelino, J. Davy Kirkpatrick, et al.
- A Study of the Diverse T Dwarf Population Revealed by WISE Gregory N. Mace, J. Davy Kirkpatrick, et al. • 2013
- Enhanced Warm H2 Emission in the Compact Group Mid-Infrared "Green Valley" M.E. Cluver, P.N. Appleton, P. Ogle, et al. • 2013
- Far-Infrared Properties of Type 1 Quasars D.J. Hanish et al. • 2013
- A Herschel Survey of the [N II] 205 micron Line in Local Luminous Infrared Galaxies --- The [N II] 205 micron Emission as a Star Formation Rate Indicator Yinghe Zhao, Nanyao Lu, C. Kevin Xu, et al. • 2013
Featured Science Authors
Featured Science Papers
We investigate the relationship between 8.44 GHz brightness temperatures and 1.4 to 8.44 GHz radio spectral indices with 6.2 micron polycyclic aromatic hydrocarbon (PAH) emission and 9.7 micron silicate absorption features for a sample of 36 local luminous and ultra-luminous infrared galaxies. We find that galaxies having small 6.2 micron PAH equivalent widths (EQWs), which signal the presence of weak PAH emission and/or an excess of very hot dust, also have flat spectral indices. The three active galactic nuclei (AGN) identified through their excessively large 8.44 GHz brightness temperatures are also identified as AGN via their small 6.2 micron PAH EQWs. We also find that the flattening of the radio spectrum increases with increasing silicate optical depth, 8.44 GHz brightness temperature, and decreasing size of the radio source even after removing potential AGN, supporting the idea that compact starbursts show spectral flattening as the result of increased free-free absorption. These correlations additionally suggest that the dust obscuration in these galaxies must largely be coming from the vicinity of the compact starburst itself, and is not distributed throughout the (foreground) disk of the galaxy. Finally, we investigate the location of these infrared-bright systems relative to the main sequence (star formation rate vs. stellar mass) of star-forming galaxies in the local universe. We find that the radio spectral indices of galaxies flattens with increasing distance above the main sequence, or in other words, with increasing specific star formation rate. This indicates that galaxies located above the main sequence, having high specific star formation rates, are typically compact starbursts hosting deeply embedded star formation that becomes more optically thick in the radio and infrared with increased distance above the main sequence.
The detection of exoplanets through direct imaging has produced numerous new positive identifications in recent years. The technique is biased towards planets at wide separations due to the difficulty in removing the stellar signature at small angular separations. Planets in eccentric orbits will thus move in and out of the detectable region around a star as a function of time. Here we use the known diversity of orbital eccentricities to determine the range of orbits which may lie beneath the detection threshold of current surveys. We quantify the percentage of the orbit which yields a detectable signature as a function of semi-major axis, eccentricity, and orbital inclination and estimate the fraction of planets which likely remain hidden by the flux of the host star.
CANDELS is a powerful imaging survey of the distant Universe being carried out with two cameras on board the Hubble Space Telescope.More Info
COSMOS is an HST Treasury Project to survey a 2 square degree equatorial field with the Advanced Camera for Surveys (ACS). The project also incorporates major commitments from other observatories, including Spitzer, GALEX, the VLA radio telescope, ESO's VLT in Chile, ESA's XMM X-ray satellite, and Japan's 8-meter Subaru telescope in Hawaii.More Info
The Great Observatories All-sky LIRG Survey (GOALS), is combining imaging and spectroscopic data from NASA's Spitzer, Hubble, Chandra and GALEX space-borne observatories in a comprehensive study of over 200 of the most luminous infrared-selected galaxies in the local Universe.More Info
The KINGFISH project (Key Insights on Nearby Galaxies: a Far-Infrared Survey with Herschel) is an imaging and spectroscopic survey of 61 nearby (d < 30 Mpc) galaxies, chosen to cover the full range of integrated properties and local interstellar medium (ISM) environments found in the local Universe.More Info
The Spitzer Wide-area Infrared Extragalactic survey is one of six very large programs undertaken as Legacy surveys during the first year of flight of the Spitzer Space Telescope. SWIRE has imaged nearly 50 square degrees (equal to the area of 250 full moons) divided among 6 different directions on the sky, detecting over 2 million galaxies by their heat radiation, some of them over 11 billion light years away.More Info
The Panchromatic Hubble Ultra Deep Field: Ultraviolet Coverage (UVUDF) is a treasury Hubble Space Telescope program using the WFC3-UVIS detector with the F225W, F275W, and F336W filters. These UV images will reach point source detection limits of AB=29, a factor of ten fainter than the GALEX ultradeep surveys.More Info
The WISP survey is a large Hubble Space Telescope pure parallel program with the WFC3 G102 and G141 infrared grisms. The broad, continuous, spectral coverage of the G102 and G141 grisms provides the best currently feasible measurement of the star formation rate continuously from 0.5 <z < 2.5.More Info