John L. Tonry, Professor
Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822
Phone: (808) 956-8701
jt at ifa dot hawaii dot edu
Areas of Interest
Cosmology, Large Scale Structure of the Universe, Distance Scale,
Structure of Galaxies, Dense Stellar Systems,
Black Holes in Galactic Nuclei, Image Processing
Type 1a supernovae (expoding white dwarf stars) may just be
reliable standard candles, and may have changed very little
since the universe was young. Such beacons, seen across the age of the
universe, can tell us whether the universe has decelerating significantly
since the Big Bang, and whether it might recollapse some day.
Our Fall 2001 campaign is in progress; here is the
log of all observations.
Our Fall 1999
campaign, sorted by supernova being followed or
log of all observations, and
light curve estimates. More information and
links can be found on the
CFA supernova page.
SBF Survey:
A Survey of Galaxy Distances Using Surface Brightness Fluctuations
This is a project to determine the distances
to the nearest 300 elliptical and S0 galaxies by measuring their
surface brightness fluctuations. We've got good photometry, the
fluctuation data are on tape and almost completely reduced,
Paper I,
Paper II,
Paper III, and
Paper IV
are out. Paper II derives a model
for the large scale flows in the local universe which you can
download as sbf2flow.f. Paper IV
has data tables of SBF magnitudes, colors, and distances which you can
download as
table.good and
table.poor.
OTCCD:
Image Motion Compensation Using an Orthogonal Transfer CCD
With Barry Burke and Dick Savoye at Lincoln Labs, I've invented a new
type of CCD (US patent 5,760,431) which can shift charge in all four
directions. So as an optical image dances around on a detector, you can
move the accumulating electrons to follow it and avoid blurring. We've built
and used a prototype device (details published in
astro-ph/9705165),
and we're in the process of making a large chip (2k x 4k)
which I'll install on the UH 88" telescope for studies of time delays in
gravitational lenses.
HST projects:
Cosmological Investigations using HST to Measure SBF
Three projects are
currently ongoing:
"The Far Field Hubble Constant"
(cycle 5: 5910) uses SBF to get distances to four BCGs and determine H0.
"The Cosmic Velocity of the Great Attractor" (cycle 6: 6579) uses SBF
to get peculiar velocities of galaxies around the Centaurus/Great
Attractor region of the sky, and determine whether the Great Attractor
really exists. "The SBF Hubble Diagram" (cycle 7: 7453) exploits NICMOS's
amazing capabilities to get distances to galaxies spread over the
entire sky as far away as 10,000 km/s and test for the global value of
the Hubble parameter.
I've a long standing interest in the uses of gravitational lenses
as probes of cosmology and lens potentials, and so I've started
contributing in the effort to collect the data necessary to make
use of these lenses. My part includes
photometric observations which can be used to detect time delays
(should the lensed object change its brightness), and spectroscopic
observations to measure the redshifts and potential depth of the
lensing objects.
DEBs:
Extragalactic Distances from Double Line Eclipsing Binary Stars
This is the DIRECT project to get fundamental distances
to M31 and M33 by finding and observing eclipsing binary stars.
Radial velocities and eclipse profiles tell you the diameter of the stars
in meters, colors tell you the temperature, Stefan-Boltzmann tells you the
luminosity, and fluxes give you the distance. Implausible? Just wait...
