John L. Tonry

John L. Tonry, Professor
University of Hawaii
Institute for Astronomy, 2680 Woodlawn Dr., Honolulu, HI 96822
Phone: (808) 956-8701
tonry at hawaii dot edu

Areas of Interest

Cosmology, Large Scale Structure of the Universe, Distance Scale, Time Domain Astronomy, Structure of Galaxies, Dense Stellar Systems, Black Holes in Galactic Nuclei, Image Processing


Astr 301: Observational Projects

Astr 734: Order of Magnitude Astrophysics

Current Research Projects

ATLAS: The Asteroid Terrestrial-impact Last Alert System

This is a new project that is complementary to (a polite way to say better than) Pan-STARRS for finding killer asteroids. ATLAS is a pair of half-meter telescopes that can only see things 10x brighter than Pan-STARRS can, so it's only able to work to a third or a half of the distance of Pan-STARRS. What's different is that ATLAS patrols the entire, visible sky twice a night, whereas Pan-STARRS is much slower. Pan-STARRS is narrow and deep; ATLAS is wide and shallow. The motivation for ATLAS is to provide warning of an asteroid on its final, impact trajectory: maybe a week's warning for a 2 Mton explosion and three week's warning for a 100 Mton explosion. Recently ATLAS found a 10 Mton asteroid ( K17Q60) that missed the us by 10 Earth radii (if we find 99 more, watch out!), and another (A103wzq) still on the MPC confirmation page whose MOID (minimum orbital intersection distance) could be less than an Earth radius (it might hit us). We're having fun.

Pan-STARRS: The Panoramic Survey Telescope and Rapid Response System

Between 2002 and 2010 I was pretty much consumed with work on the Pan-STARRS project. This is an AFRL funded effort to build a telescope and imager to carry out wide-field (3 deg), deep imagery of the whole sky. What's different about Pan-STARRS is that we are doing this every night and covering the whole sky many times. Therefore Pan-STARRS is far better than anything ever before for finding moving objects, variable objects, and transients. I'm interested in finding supernovae, of course, but we're all in this to help reduce the risk of the Earth being whacked by an unseen asteroid. The IFA is joined by a Pan-STARRS Science Consortium who are carrying out the science mission of the first Pan-STARRS telescope.

High Redshift Supernovae: Studies of Cosmology from Observations of Type 1a Supernovae

Type 1a supernovae (expoding white dwarf stars) are reliable standard candles, and 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. This work, starting with the High-z program, branching into the Higher-z and ESSENCE projects, led us to announce in 1996 that the universe is undergoing an accelerating expansion because of "Dark Energy", a cosmological constant. Although we really felt like we were going out on a limb, the evidence was clear and it's been reconfirmed many times over since then.

Our Fall 2001 campaign was (long ago, sorry) 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. This has

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 built and used a prototype device (details published in astro-ph/9705165), and we also made a large chip (2k x 4k) which I installed on the UH 88" telescope. This OPTIC camera has been used for some of the very best light curves of extra-solar planet occultations from the ground.

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