Next: John W. Evans (1909-1999)First Head of Solar Observatory
Previous: Livermore Imaging Fourier Transform Spectrograph at the McMath-Pierce Telescope
Table of Contents - Search this issue - NOAO Newsletter Home Page

NOAO Newsletter - NOAO Highlights - December 1999 - Number 60


KNOTES from the Hodgefest

Knut Olsen (kolsen@noao.edu)

(Since much of Paul Hodge's work, and that of his students and associates, has been carried out in the southern hemisphere and at CTIO, we are pleased to present this conference summary from a former Hodge student and present CTIO postdoc. The Editor.)

On 9-11 September 1999 more than 40 astronomers converged on Friday Harbor, WA to acknowledge and celebrate the profound influence that Paul Hodge has had on their lives and astronomy. Officially dubbed the Hodgefest (but some preferring "Hodgeapalooza"), the meeting had the atmosphere of both a serious scientific conference and a family reunion. This mix was decidedly appropriate, as Paul has played a leading role in fields as diverse as meteoritics and the distance scale, while also earning the universal admiration of students and colleagues through his kindness and enthusiasm. But by no means was the meeting a send-off party; rather, it was an opportunity for Paul's friends to place a milestone along the path of his career. As Professor of Astronomy at the University of Washington, Paul continues to edit the Astronomical Journal, supervise many of the Department's graduate students, and conduct his own astronomical research.

A well-organized set of oral sessions and accompanying posters on subjects representing Paul's many research interests occupied the bulk of the meeting. Don Brownlee (Washington) led off the meeting with an update on Stardust, a NASA Discovery mission currently in flight that will collect cometary particles from Comet Wild 2 and interstellar dust grains, returning the samples to Earth. Don's description of the mission and his video of the launch were impressive, as was his slide of himself and Ed Olszewski as graduate students. The focus of the meeting then drifted outwards in distance. Ivan King (Berkeley) showed impressive results of using HST to derive proper motions of globular cluster stars, establishing membership and distance through statistical parallax.

The Magellanic Clouds, the subject of Paul's thesis work, merited their own session. Paul introduced the concept of the open cluster specific frequency in considering how to quantify a galaxy's ability to produce open star clusters. The Clouds have been very successful in producing clusters, in stark contrast to galaxies such as IC1613, which have produced practically zero clusters despite their active state of star formation. The concept of separate field star and cluster modes of star formation is confirmed through analysis of the field star formation history of the LMC, discussed separately by Jason Harris (UCSC) and Knut Olsen (CTIO); field star formation appears to have been active in the LMC over a period where few, if any, clusters formed. Olsen echoed a suggestion by Sidney van den Bergh (HIA) that the LMC's Bar may aid in forming clusters.

Much attention was given to the Local Group, one of Paul's favorite astrophysical laboratories. Sidney van den Bergh and Eva Grebel (Washington) gave excellent reviews. Eva focussed on the evolutionary histories of Local Group dwarfs; she concluded that there is no evidence that dwarf irregulars and ellipticals represent exclusive sets of stellar populations—there is simply too much variety in their star formation histories. This idea was supported by the many population boxes (a concept introduced by Paul in 1989) of LG dwarfs shown at the meeting: LGS3 (Bryan Miller, Leiden), NGC 185, NGC 205 (Myung Gyoon Lee, Seoul), and Sextans A (Robbie Dohm-Palmer, Michigan), among others. Much of this work was based on HST data, and the color-magnitude diagrams contained spectacular detail; Eline Tolstoy (ESO) showed that the new 8-m ground-based telescopes (e.g., the VLT) will provide still more detail, and extend resolved stellar population work to galaxies outside the local Group. Eric Wilcots (Wisconsin) discussed his ongoing survey of HI gas in Local Group galaxies; while dwarf spheroidals appear to contain very little gas, confirming past searches, one dwarf may harbor distant HI—perhaps the signature of blowout of the ISM. This concept of gas blowout as a result of active star formation in dwarfs was supported by the thorough abundance analyses of Evan Skillman (Minnesota). George Wallerstein (Washington) extended the definition of what makes a Local Group galaxy by suggesting that the globular cluster w Cen, unique among clusters in containing both an age and metallicity spread, may in fact be the nucleus of a dissolved dwarf galaxy.

Moving beyond the Local Group, Rob Kennicutt (Arizona), representing the HST H0Key Project, made a good case for the Project's claim that H0 is now known to an accuracy of 10%. Rob acknowledged that astronomers have reason to be suspicious of such a claim, since H0 has changed by a factor of 10 since Hubble's discovery of the expansion, while published error bars have remained roughly constant (10%). However, Kennicutt argued that parallel rungs of the distance ladder traditionally at odds are now converging to the same value. Much of the remaining uncertainty now hinges on the distance to the LMC. Peter Garnavich (CfA) argued for the benefits of using red clump stars as distance indicators, which produce a distance to the LMC smaller by ~10% than that adopted by the Key project.

There was also plenty of time for social activities, with Friday Harbor offering whale-watching, kayaking, bicycling, and pleasant surroundings for exploration. Despite the attractive venue and superb scientific program, however, not all of the expectant registrants attended, weakly excusing themselves because of HST proposals or other engagements. The worst excuse was judged to be that of Brooke Skelton, who claimed that she was stranded on Orcas Island after a ferry crashed into and splintered the dock—for this whopper of a tale she was offered a prize by Mario Mateo of the Scientific Organizing Committee (1). Nevertheless the conference was well attended, with astronomers arriving from such distant locations as Moscow, Seoul, and Concepción, Chile—though none, argued Mateo, had travelled as far as George Wallerstein, who "comes from another planet."

Thanks go to the SOC—Mario Mateo, Don Brownlee, Schuyler van Dyk, Eva Grebel, Rob Kennicutt, Evan Skillman, and Ed Olszewski—and, of course, Paul Hodge, for making Hodgefest `99 a brilliant success.

(1) New reports have since confirmed Brooke's story of the fiery crash.


Next: John W. Evans (1909-1999)First Head of Solar Observatory
Previous: Livermore Imaging Fourier Transform Spectrograph at the McMath-Pierce Telescope
Table of Contents - Search this issue - NOAO Newsletter Home Page

NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation