Richard Nolthenius

Visiting Researcher, University of California, Santa Cruz

Welcome! You've reached the cyber-home of Richard Nolthenius (Rick to my many friends!)... Here you can browse my recent research and, eventually, other interesting items as well. I split my time between being full time at Cabrillo College down the road where I run the Astronomy Department, and doing research here at UCSC. As a teacher, my mission is to quash the forces of cotton-headedness which run RAMPANT in this town. In my other life, I also enjoy triathlon, trading in financial markets (sure won't get rich doing astronomy), photography, rock climbing, surfing, kayaking, mountain biking, painting in watercolor, Rachmaninoff, and occasionally U2, Peter Gabriel (for various other moods), and coffee house discussions about everything from philosophy to relationships to the latest training ideas, since I especially love training and racing, mostly in triathlon.

Research Interests

Galaxy Groups and Cosmology

Since my post-doc days in the mid-80's, I've carved out a niche for myself by showing the value of studying galaxy groups to understanding galaxy formation and cosmology. Groups have often been ignored and neglected... too poor, too messy, too contaminated by non-group members...too ugly! But if one overlooks their rather unglamorous appearance and instead focuses on their inner beauty (to put a Santa Cruz spin on it), we find that groups in fact may have a suprisingly strong statement to make about how the universe was really put together.

In the 90's I worked with Anatoly Klypin (NMSU) and Joel Primack (UCSC Physics) on comparing large scale numerical simulations of (then) standard Cold Dark Matter and Cold + Hot Dark Matter to complete magnitude limited galaxy surveys. The hot dark matter was assumed to be in the form of massive neutrinos, with mass in the few eV range. These (Klypin's) simulations had sufficient resolution to study galaxy groups, but not individual galaxies. My part was to devise statistical measures of groups which were both robust and provided good discrimination between cosmological models. The first paper, NKP94, appeared in early '94 in ApJ Letters. The full paper on this was published in the Astrophysical Journal.

Formation of Galaxies and Galaxy Groups

I've also worked with Dave Burstein (ASU), Sandra Faber (Lick), and Ralf Bender (U. Munich) on measuring the properties of dissipational structures from galaxies on up through galaxy groups and clusters in "kappa space". Kappa space is a 3-space whose coordinates are made of combinations of the following properties: galaxy mass, M/L, and central surface brightness. We've found that all collapsed stellar systems form fundamental planes perpendicular to a common plane, and all show increasing M/L with mass. These kappa-space projections provide a valuable dataset for comparisons with cosmological model predictions, and will give valuable insight into formation mechanisms. The astro-ph version of the paper is here.

Observational Studies of Star-Spot and Eclipsing Binary Variables

At Cabrillo College, I've introduced students to observational astronomy by engaging them in photoelectric photometry of bright variable stars. Aside from numerous minima timings of eclipsing binararies, the most noteworthy results have been the first clear photometry on the descending branch of the long period eclipsing Wolf-Rayet star 22 Vul, participation in the multi-longitude campaign to search for short-term chromospheric activity on the RS CVn star V711 Tau, and long term monitoring of light curve changes associated with mass loss from the Wolf Rayet eclipsing binary CQ Cephei. Most interesting of all, Cabrillo photometry discovered the most intensely spotted star on record. Following announcement of strong chromospheric spectroscopic activity, HD 12545 was monitored at Cabrillo in BVRI and found to show a 25 day photometric cycle with a record peak amplitude in B of 0.7 magnitude and 0.6 in V (Nolthenius 1991 IBVS 3589)! Strassmeier and Olah (1992, AA 259, 595) used these and his own later observations (when the amplitude had declined somewhat) to attempt to determine star spot coverage and geometry. Such large amplitudes are a challenge to current solution methods, since spot coverage and temperature drop approach their maximum possible values. The star was later put under regular observation using automated photometric telescopes and results are published in PASP.

Instrumentation/Facilities Projects

In Spring '96 I began a major upgrade of the observatory at Cabrillo College, spending virtually all of the (meager) funds I'd managed to squirrel away for the past several years. We've converted a 20 ft steel shipping container into an observatory building, with a deep concrete pier poking through the roof (yes, I dug the damn hole and wired together the damn re-bar myself!). With lots of help from the Cabrillo Astronomy Club (with many years of construction experience, fortunately) we now have a fiberglass dome and the a wood-panelled interior. The dome includes infrared sensors interfaced with the dome motors to automatically keep the dome slit centered on the telescope. The pier now holds a 12" Meade LX200 Schmidt Cass which operates at either f/10 or f/6.3. Instruments include an SBIG STV autoguider, and an Optec SSP3A single channel photometer with Johnson BVRI filters. We also have a Santa Barbara Instrument Group ST-7XE CCD camera, using the Kodak 416 chip (768x512) with a 2 stage TE cooler operating at -40C below ambient with Johnson BVRI and tri-color visual filter sets. The LX200 has an on-board computer and dual axis drives. It interfaces with a PC which will control telescope positioning as well as the filter settings and the CCD operation. The computer system is a Win98 P4 for telescope control and object selection/acquisition (from the full Hubble Guide Star, SAO, NGC, IC, and UGC catalogs).

In Summer '03 Cabrillo College Observatory was moved to a canyon site below the hilltop above the main campus in Aptos. It is at the end of the dirt road to the college's water wells, in Porter Gulch. It is a darker site, with reasonable but not great horizons. In 2008 I designed and helped construct a second building which houses the 12" Meade LX200 now on a Losmandy G11 mount with Gemini computer control, separate warm room for control computers, and space for students to work on projects. At the Cassegrain focus we have mounted an SBIG ST2000XCM or ST7xe CCD cameras for imaging and for photometry.

Planetary Transit Searches

October 2009: I've just begun working with Greg Laughlin and Steve Vogt to gear up for using the Super-LOTIS telescope at Kitt Peak for getting millimagnitude level differential photometry of transiting exo-planet candidates. The possibilities of getting the required photometric accuracies are looking good, and as of late '09 I'm working on getting together a data pipeline for processing the images in an efficient manner.

Greedy Capitalist Interests

When I got the Optec SSP3 photometer, I found it had no good software for data acquisition, and no software at all for data reduction. I saw dollar signs! (well a dollar sign or two anyway). The result was RPHOT (Reduction PHOTometry package); a complete data acquisition and data reduction package under DOS. It's distributed and marketed exclusively by Optec, Inc. and for the privelege they continued to send me nice, quarterly royalty checks until '05.


Trading financial markets has also become a significant interest of mine. I've developed some profitable trading models.

Richard Nolthenius
UCO/Lick Observatory
University of California
Santa Cruz, CA 95064
(831)479-6506 (Cabrillo College Office)
internet: rickn, rinolthe