P&A Brochure - Astrophysics/Astronomy

    Activity across virtually the entire range of modern astronomy can be found at JHU and the Space Telescope Science Institute (STScI), which is right across the street from the Physics & Astronomy Department. Hopkins astronomers are at the leading edge of work in various astronomical subfields, all the way from the nature of the solar system to the origin of the universe.

    Building astronomical instrumentation and then exploiting it for scientific discoveries has long been a particular strength of our group. Hopkins astronomers have had major roles in the Hubble Space Telescope (HST) project from the start: they helped build one of its four original instruments, the Faint Object Spectrograph (FOS), and one of the two instruments Corrective Optics Space Telescope Axial Replacement Instrument (COSTAR) that corrected the spherical aberration in the HST's primary mirror. Led by Professor Holland Ford, they are building the Advanced Camera for Surveys, which was installed in the HST on March 7, 2002 during a shuttle visit.

    The late Professor Arthur Davidsen directed the team that designed and built the Hopkins Ultraviolet Telescope (HUT), which flew twice aboard the space shuttle, obtaining over 400 far-UV spectra (90 to 180 nm) of active galaxies, hot stars, supernova remnants and planets. Perhaps the most exciting result was the first measurement of the amount of ionized helium in the intergalactic medium, revealed by its absorption of light from the distant quasar HS1700+64.

Professor Warren Moos is the principal investigator for the Far Ultraviolet Spectroscopic Explorer (FUSE), a satellite developed and operated by JHU. FUSE was launched in June of 1999 and, with a recent extension granted by NASA, is slated for operations until at least December 2004. FUSE performs high-resolution spectroscopy in the far-ultraviolet region from 90 to 120 nanometers with much higher sensitivity and spectral resolution than HUT. Its primary scientific goals will be to measure the deuterium abundance in different environments throughout the galaxy, a key parameter in models of Big Bang cosmology, and to determine the distribution of hot gas in the interstellar medium of our own Galaxy and nearby galaxies.
The FUSE instrument in the clean room at the JHU Applied Physics Laboratory

JHU is a major partner in the Galaxy Evolution Explorer (GALEX) satellite, which will survey the entire sky for stars, galaxies and quasars that are bright in the ultraviolet. GALEX will determine the history of star formation in galaxies at red shifts from 0 to 2, and will identify one million quasars. Its data archive will be developed and managed by JHU research scientist Luciana Bianchi.

    Johns Hopkins is the principal institution for the Primordial Explorer (PRIME), which has recently been selected for Phase-A atudy, with research scientist Wei Zheng as the principal investigator. The proposed mission will carry out a deep sky survey in four near-infrared bands, as a pilot mission for the Next Generation Space Telescope (NGST). PRIME will reach an epoch during which the fist quasars, galaxies and clusters of galaxies were formed in the early Universe, and detect hundreds of brown dwarfs and even Jupiter-size planets.

    JHU is also an active partner in the Sloan Digital Sky Survey (SDSS). The SDSS will collect images of one-quarter of the sky in five colors, compiling a catalog of 100 million objects and their associated photometric parameters. Spectra will be taken of one million galaxies and 100,000 quasars. This survey will permit studies of the structure of the universe at the largest scales that can be causally connected, as well as statistical analysis of the properties of galaxies, quasars and stars in our galaxy at a totally unprecedented level of detail and reliability. Research astronomer Alan Uomoto built the two spectrographs for the 2.5-m survey telescope, and Professor Alexander Szalay is directing the design and construction of the SDSS data archive. Professor Karl Glazebrook studies the properties of faint high-redshift galaxies and is invoved in the 2dF Galaxy Redshift Survery as well as SDSS. Here are some graduate student opportunities associated with SDSS.

   Not all space astronomy is done on major facilities requiring the efforts of large teams. Prof. Paul Feldman, an expert on comets, leads a group in which individuals, often graduate students, build their own experiments to fly on sounding rockets.

    In addition to these instrumentation projects, Hopkins astronomers are very active users of already-existing observatories, both on the ground and in space. Their observations span the electromagnetic spectrum from radio frequencies to gamma-rays. Since its launch, JHU astronomers have received thousands of hours of observing time on HST and have accounted for many of its most notable achievements. Many Hopkins astronomers also have substantial X-ray observing programs, an activity that has expanded dramatically in the next few years with the launches of the Advanced X-ray Astronomy Facility (AXAF), the X-ray Multi-Mirror Telescope (XMM) and the X-ray spectroscopy mission ASTRO-E. Professor David Neufeld is a member of the team that designed the Submillimeter Wave Astronomy Satellite (SWAS) that was launched in December 1998. For ground-based optical work, JHU has 8 percent of the time on the Apache Point Observatory 3.5m telescope in New Mexico, and Hopkins astronomers also successfully compete for large blocks of time at national observatories, such as the Cerro Tololo Inter-American Observatory in Chile.

    A sampler of recent achievements in observational astronomy at Hopkins might include Professor Timothy Heckman's work on starburst galaxies and Professor Rosemary Wyse's on the stellar populations and structure of our own galaxy. Starburst galaxies are galaxies in which the current rate of star formation greatly exceeds the average rate over the history of the universe; Professor Heckman's efforts have significantly deepened our understanding of these dramatic objects. Professor Wyse and her collaborators discovered that the long-held view of our galaxy as comprising a thin disk of relatively young stars centered on a spherical "bulge" of older stars had to be expanded to include an additional "thick disk" of old stars.

    In the last decade, JHU has become a major center for theoretical astrophysics. Hopkins theorists are at the forefront of a number of the hottest areas in astrophysical theory. Professor Alexander Szalay has pioneered the application of sophisticated statistical methods to the study of the large-scale structure of the universe. By virtue of his supervision of the SDSS data archive, he is poised in the best position to make use of this extraordinary tool. Professor Colin Norman has contributed seminal ideas in many diverse areas, from stellar dynamics in galaxies to the interstellar medium. Professor Julian Krolik is one of the world's most active theorists in the effort to understand accreting black holes, from binary star systems in our own galaxy to quasars and other active galactic nuclei. Professor Neufeld is well-known for his expertise in molecular astrophysics and the interstellar medium. Professor Ethan Vishniac, the director of the Center for Astrophysical Sciences, studies accretion disks, magneto hydrodynamic turbulence and reconnection, and the large sacle structure of the universe.

    Graduate students at JHU participate in all aspects of astrophysics research, from building hardware for instruments and going on observing runs at telescopes all over the world to analyzing data from astronomical spacecraft and doing detailed theoretical calculations. Several students wrote their theses based on the HUT data; some found themselves in the midst of such cutting-edge HST work as the Cosmic Distance Scale Key Project; others will certainly be among the first to cull science from the SDSS. The breadth of strengths represented in the department means that students have a wide choice in research opportunities, a range of options widened even further by the possibility of working with astronomers at the STScI, or even with scientists at the NASA Goddard Space Flight Center. As a group we pride ourselves on openness and flexibility, so there are no limits to what a graduate student can accomplish here.

Faculty: Allen, Beckwith, Blair, P. Feldman, Ford, Giacconi, Glazebrook, Hauser, Heckman, Henry, Kinney, Kriss, Krolik, Livio, Long, Moos, Mushotzky, Neufeld, Norman, Postman, Strobel, Tsvetanov, Vishniac, Weaver, Williams, Wyse.