My research centers around issues of low surface brightness (and possibly "no surface brightness") objects. I am interested in dynamical estimates and observational determinations of the amount of mass present in a wide variety of objects--clusters of galaxies, groups of galaxies, individual galaxies, and even planetary nebulae. My slant on this research is to investigate whether our natural human bias toward visible wavelengths of light has biased us against detecting certain classes of objects.

The class of low surface brightness galaxies appaears to be large but it is poorly studied. These galaxies' visual surface brightnesses barely exceed the sky background and have therefore been overlooked in most optical surveys. However, dynamical studies we have made of these galaxies' rotation speeds indicate that they are comparable in mass to the largest "normal" spiral galaxies. The mystery is why they show such weak star formation despite their mass. This may be due to a lack of interactions with other galaxies,

A more fundamental question is how many of these objects populate the universe? Unfortunately, objects with little star formation are difficult to detect at almost any wavelength, since stars are the ultimate source that powers almost all of the emission from galaxies. One of the only alternatives is to study the emission of neutral hydrogen at 21 cm, which is a primordial material and does not require starlight to excite the transition.

Our blind surveys are detecting many previously uncataloged objects which have a wide range of properties. They include nearby faint dwarf galaxies, peculiar objects which defy simple classification schemes. and the low surface brightness giants described above. Optical images of HI-detected galaxies are shown here. This research is perhaps an indication that much of our understanding of extragalactic space is still in its infancy.

I have undertaken a wide array of observations here at the Five College Radio Astronomy Observatory, and at observatories around the country: the Arecibo Observatory in Puerto Rico, the VLA in New Mexico, the GBT in West Virginia, Nancay in France, and Kitt Peak in Arizona.

Astronomy Course Pages

Astronomy 100 Exploration of the Universe

Selected Publications

• Pathways to Astronomy, S. E. Schneider and T. T. Arny, 2006 (McGraw-Hill) -- a college-level introduction to astronomy.

• "The Contribution of HI-rich Galaxies to the Damped Ly-alpha Absorber Population at z = 0," J. L. Rosenberg and S. E. Schneider, 2003, Astrophysical Journal 585, 256-267 -- how characteristics of the galaxies discovered in HI surveys appear similar to sources identified in absorption studies of quasars.

• "The Arecibo Dual-Beam Survey: The HI Mass Function of Galaxies," J. L. Rosenberg and S. E. Schneider, 2002, Astrophysical Journal 567, 247-257 -- results of the largest "blind" HI survey at Arecibo before the building of the ALFA receiver system.

• "A Warped Disk Model for M33 and the 21-cm Line Width in Spiral Galaxies," E. Corbelli and S. E. Schneider 1997, Astrophys. J, in press. --our nearby companion galaxy has a peculiar structure which suggests some possible problems in estimating galaxy distances

• "The HI Luminosity Function from `Blind' Surveys," S. E. Schneider 1997, Pub. Astron. Soc. Australia 14, 99-105 --past, present, and future determinations of the mass distribution of neutral hydrogen among galaxies.

• "Neutral hydrogen around early-type galaxies," K. DuPrie and S. E. Schneider 1996, Astron. J., 112, 937. -- a student's senior project to study the gaseous environment around gas-poor galaxies.

• "HI Selection Effects and the Galaxy Mass Function," S. E. Schneider 1996, in Minnesota Lectures on Extragalactic HI, ed. E. Skillman, ASP Lecture Series, pp. 323-356. -- a graduate level description of how optical and radio observations of galaxies are used to determine the total mass of these populations

• "Neutral Hydrogen in the M96 Group: The Galaxies and the Intergalactic Ring," S. E. Schneider, 1989, Astrophys. J., 343, 94-106. --evidence of dynamical interactions between an unusual intergalactic cloud in a group of galaxies, and its implications for the presence of dark matter

• "Between the Galaxies," S.E. Schneider and Y. Terzian, 1984, American Scientist, vol. 72, pp. 574-581. --a popular introduction to the topic of dark matter

Awards

• 2001 Hewlett Teaching Fellowship
• 2000 College Outstanding Teacher Award
• 1997-98 President, UMass Chapter of Sigma Xi
• 1991 Presidential Young Investigator Award
• 1987 Trumpler Award of the Astronomical Society of the Pacific for outstanding thesis in North America
• 1979-83 National Science Foundation Fellowship
• 1979-80 Cornell Sage Fellowship

Education

• Ph.D. in Astronomy, Cornell, 1986 -- Thesis: Galaxy Groups: Neutral Hydrogen and Dynamics
• M.S. in Astronomy, Cornell, 1982
• B.A. Magna Cum Laude in Astronomy and Astrophysics, Harvard