The central region of the starbursting galaxy Messier 82
as imaged by the new 7mm receivers at the VLA
Volume 32, Number 2
May 2001
A quick browse of the issues available on-line shows that the
present issue is one of the longer ones. We've all been busy. Much
of this activity is not even reported here. An incomplete list
includes (1) open houses on Astronomy Day and Take Our Daughters to
Work Day which attracted hundreds of visitors, (2) the Thursday and
Saturday tour programs are operating smoothly, (3) the department
brochure project is nearly completed, (4) there are plans for
upgrading and automating telescopes at the St. George and Scarborough
campuses, (5) the first call for Magellan proposals has gone out, (6)
our graduate program is again under review, and (7) the DDO-GRB
project is at an advanced stage. The next few issues promise to be
excellent. Stay with us!
In August 2000, at the height of thunderstorm season, time was awarded for a 7mm observation of M82. On the day of the run the TO reported that "thunderstorms were in the area", but fortunately nothing blew over the array itself. The VLA is currently in the process of upgrading all 27 antennas for work at 7mm. When the observing proposal was submitted, only 9 antennas were re-surfaced and had the new receivers installed; S/N estimates were calculated appropriately. Fortunately for us, by the time the observations came around fully 18 of the antennas were operational, which helped create this sensational image. It was recommended that "fast-switching" mode be used, which allows for very quick alternation between the source and the calibrator. A turn-around time of 15 minutes was recommended, but upon viewing the weather conditions early in the summer a calibration cycle of 5 minutes was chosen. This time helped keep the phase stability to an average of about 75 degrees (post calibration), an appalling large number for those of us used to working at cm wavelengths (and phase stability at one degree or less).
The image itself is dominated by free-free continuum emission. In the brighter regions the thermal emission dominates over the non-thermal by a factor of 10 or more. Some of the features visible here are a central semi-complete ring of ionized gas about 250 pc in diameter, and two lanes of ionized gas extending to the extreme east and west of the image. Such a structure is thought to indicate the existence of a barred morphology. Simulations show that barred potentials in galaxies can efficiently channel gas into the galactic nucleus resulting in the intense starburst that powers M82. Ultimately it is thought that the barred morphology resulted from a tidal interaction with the large nearby spiral M81.
M82 is probably the most studied object outside of the Milky Way. It is of interest to people studying star formation in a statistical way on a galactic scale. Although detailed modelling exists for the starburst, the results are still quite crude. This image will serve to help pin down the properties of the upper main sequence population of stars in the nucleus, and the degree of spatial organization clearly visible here will help to determine the star formation history of the galaxy. In the broadest possible context, nearby dwarf starbursts such as M82 will help to provide a model of galaxy formation and associated phenomena (i.e., galactic superwinds and chemical enrichment of the ISM/IGM) in the early universe.
Image courtesy and copyright M. Allen, T.E. Clarke and
P.P. Kronberg.
After the initial training related to the TO'ing, Heide will learn data reduction routines to help with the mounting pile of binary-star results that we have acquired recently with the 1.88m telescope.
We welcome Heide on board and hope that the TO work will be interesting and enjoyable to her.
Chris Burns (graduating from our PhD program) is recognized as an excellent scholar, an outstanding teacher, and a leader and supporter of his peers. Through Let's Talk Science, through the public open house program, and through the Toronto Sidewalk Astronomers, he has brought science to the streets, to the schools, and to the public.
Joe Wilson (graduating from our Major program) is recognized for promoting, through leadership and example, student participation in scholarly work: undergraduate research, science outreach and journalism, and dissemination of students' academic work through conferences and publications.
We enjoyed the visit from Wendy Freedman in February, especially the relaxed student reception with her at Mike and Jennifer's place. We reminded her of her days as a GASA operative (she was faculty meeting rep, from what I've been able to discern in our archives), and she had useful career advice and research suggestions for us. Those of us who spent some time with her that week were quite pleased to get to know her. The Helen Sawyer Hogg Visitorship Committee put a lot of work into this visit and it really paid off! Thanks to Toni, Lillian, Marlene, Christine and Jennifer from the committee, as well as, of course, Peter.
The Vernal Equinox party was graciously hosted again this year by Ue-Li Pen. Scores of people came out for a little food, liquid refreshment, and to meet prospective students. A Stropella performed pieces by Brahms, Dowland and Josquin. Lawrence and I performed a Fauré song as a sort of preview for our debut recital, coming up May 23rd at 7:30 in the Hart House Music Room.
Devon Hamilton has successfully defended, Mike Gladders and Chris
Burns have got jobs for the fall. Apologies if I've missed someone
else. So, we'll be saying goodbye to all of them soon... Mike is
going to Carnegie, and Chris to Swarthmore in Pennsylvania. I've
heard several new students have accepted for next year, and there's
more on the way, so we're looking forward to seeing new faces (no
offense to the old fogies, I'm going to be one soon, maybe next
year!).
DDO has received the new CCD system for the Cassegrain spectrograph. It is a liquid-nitrogen cooled system from Jobin-Yvon in NJ. It is based on a 800x2000, 15 um thinned, back-illuminated chip which has a very high quantum efficiency of about 90% in the yellow part and about 50% in the blue part. The system should be therefore about 2.5 and 5-10 more sensitive, respectively, than the current chip. The currently used 1024x1024, 19 um chip will be permanently mounted on the Echelle spectrograph.
The cost of the J-Y system was C$45k, in that C$30k of the NSERC equipment grant (signed: Rucinski, Fernie, Garrison, Mochnacki; with contributions of Gladders, Hall and Wade), and C$15k contributed by the DA by the decision of the Chairman.
The CCD system has just passed the acceptance tests and will be now adopted to the specific needs of our spectrograph. Several tasks must be done. Here is the split into the three groups: mechanical, electronics and software.
Mechanical:
Electronics:
Software:
As is true every year, this past fall saw a number of our grad student colleagues, myself included, wade into the job market. My own foray towards a postdoc began with a trip to the IAU General Assembly in Manchester. This was followed shortly by a workshop in Birmingham, attended by many familiar faces and friends (such as previous Toronto graduate Omar Lopez-Cruz). A third conference in Preston, on wide field surveys, followed shortly thereafter. These conferences once again highlighted for me the importance of getting out and "being seen". For example, at the end of the two day Birmingham conference I was approached by Alan Dressler of Carnegie, who introduced himself by saying "why haven't I met you before?" A spirited discussion followed, motivated in part by my disagreement with a piece of the analysis he presented during the meeting. Well, I'm now the 2001 Carnegie Fellow, and though I'm sure that single incident isn't the only reason, I'm also sure it didn't hurt my chances.
The next job-hunting trip was to the AAS Winter Meeting in San Diego. Again, lots of familiar faces and ex-Torontonians were in attendance. I ended up spending most of the meeting sick with the flu, but managed to attend a few sessions. Again, I was struck by the importance of going to conferences for grad students, as I got to meet a number of people who had until then been simply names on papers. So, to all you new students, get out there! All astronomical meetings are listed by the CADC; if your supervisor doesn't suggest something - and they often won't - have a look at the list yourself and start prepping a paper!
One of the great appeals of the overseas astronomy conference is the opportunity to take a few days to relax, travel, and see the country you're in. During a trip to the UK this past August I managed to spend 5 days travelling through Scotland with ex-Torontonian Tracy Clarke. The trip was a whirlwind; we were on the road for 5 days, and, starting in Manchester, drove about 1600 miles in that time. As both Tracy and I are avid photographers, we took a large number of pictures - about 30 rolls between the two of us. A few of these are shown below.
Higlights of the trip included a series of ruined Abbeys in the lowlands, the Isle of Skye, Loch Ness, the Isle of Staffa and Fingal's Cave (known perhaps to those familiar with Mendelssohn's Hebrides Overture), and the Isle of Iona. A particular moment which encapsulates the "Scottish" experience occured on night two, on Skye. We had already retired for the night, to our tent on the moor. The sky was still light, though it was past 10 (Skye is about as far north as Churchill, though lacking in polar bears!). As the settling sheep bleated quietly on a nearby hill, we suddenly heard the faint mournful playing of a lone piper. A pleasant way to fall asleep *.
*Well, for me anyway. According to Tracy I drifted off blissfully and immediately started snoring, drowning out both the sheep and the piper! She had to fall asleep to this less pleasant symphony.
There is much debate among scientists about the population of extraterrestrial, intelligent civilizations (ETIs) in the Galaxy. This debate does not centre on "if" there are ETIs, but rather, "how many" ETIs there are. A few decades ago, this debate would only occur in the more venturesome journals and in conference proceedings. The last few years have seen the publication of a few books, valuable for the layperson as well as the scientist. These books cover a wide range of topics, such as biochemistry, evolutionary biology, geology, and astronomy; typically, however, an author will focus on his or her specialty. In this article, I will highlight some of the most significant contributions to the growing body of literature on ETIs. I will restrict myself to publications readable by the layperson.
Material that is more than a decade old has become dated, due in part to technological advances, and to the commencement of large-scale organized surveys of the radio sky. An early and influential volume was published in 1966, and is entitled Intelligent Life in the Universe, by Sagan and Shklovskii. Although based on a conference proceeding, this volume is still quite readable and introduces many of the fundamental concepts referred to by other authors. A good summary of the work done up until the early 1980s is presented by Brin, The Great Silence: The Controversy Concerning Extraterrestrial Intelligent Life (1983, QJRAS, v. 24, 283). Both of these references concentrate on astronomical and engineering issues. For those who wish to avoid the journals and conferences, then I recommend Asimov's friendly approach in Extraterrestrial Civilizations (1979, Crown).
The textbook currently in use for our "Life in the Universe" course is The Search for Life in the Universe", by Goldsmith and Owen. The second edition, published in 1992, will be replaced by the third edition which is expected to be released this year. It serves as a good textbook because it reviews many different issues, including modern cosmology, stellar physics, planetary geology and atmospheres, carbon-based chemistry, DNA and its functions, and evolution. There is also a chapter debunking the ETI interpretation of UFOs. There will be some competition in the textbook market in the next year or so, when other books of this nature are scheduled to be released.
For those who wish a more detailed look at the biological aspects of life in the universe, I recommend two books, Rare Earth by Ward and Brownlee (2000, Copernicus), and Cosmic Dust by Christian de Duve (1995, BasicBooks). The book Rare Earth concentrates on the evolution of life. Their thesis is that simple life, perhaps at the single-cell level, will probably form at virtually every potential life site. However, the steps needed to build complex life, and animals in particular, are so difficult that intelligence in the universe is rare. This conclusion can be contrasted with de Duve's.
In the book Cosmic Dust, de Duve (a nobel laureate) presents the idea that evolution is a compelling process that inevitably will lead to increasing complexity once life has formed, based upon the dual truths of natural selection and continual mutation. This book contains a detailed look at evolution at both the chemical and morphological levels.
Both Rare Earth and Cosmic Dust are well-referenced volumes, and provide (or condemn) those of us with an interest in the subject area with lots of valuable reading material.
There are plenty of books that I have not yet had time to evaluate, but which look interesting at first glance. For example, Bruce Jakosky is a geophysicist and Director of the Center for Astrobiology at the University of Colorado. He has published The Search for Life on Other Planets (1998, CUP), which appears to contain a lot of good material on the inner solar system. Another example is Aliens: Can We Make Contact With Extraterrestrial Intelligence? by Andrew Clark and David Clark (1999, Fromm). The authors appear to exhaustively examine the famous Drake equation. And finally, a book that looks to be thorough, rigorous and unbiased is Simon LeFay and David Koerner's Here be Dragons: The Scientific Quest for Extraterrestrial Life. The authors (a biologist-journalist and an astronomer) pull together a lot of information on many different topics, from planets and computers to extremophiles and anthropic arguments.
Hopefully, this article will serve as an inspiration to the reader to look at some of the better literature available on the topic of ETIs, and when something is found, to inform me about it. I am always on the lookout for good material to supplement the writing component of AST251, "Life in the Universe". A report on the first two years of the writing component for this course will be available from me quite soon.
I learned from Judith Irwin that Vic Hughes passed away on Monday, April 23, 2001, while recovering from a fall he had suffered. Perhaps only the senior members of our department knew Vic, but he was one of the radio astronomers responsible for the early development of radio astronomy at Queen's University. He was also a true pioneer in the field, since he was among those responsible for the early development of radio astronomy at Jodrell Bank, where of course much of radio astronomy was developed. During his active career at Queen's, Vic and I shared a common interest in the emerging field of stellar radio astronomy.
Vic's death thus marks the loss of an historic figure in both
Canadian and world astronomy.
The following list of papers is not necessarily comprehensive. For others, refer to:
For more information about preprints, more sources, and an astronomy preprints project, see Preprint Sources
Bagnulo, S.;Wade, G.A. A study of polarized spectra of magnetic
CP stars: predicted vs. observed Stokes IQUV profiles for beta CrB and
53 Cam.
February 12,2001. Preprint No. 2001-0005
Kerton, C. R.;Martin, Peter G. ;Johnsone, D.;Ballantyne, D. R. A
submillimeter view of star formation near the H II region KR 140.
February 26, 2001. Preprint No. 2001-0003
Wade, G. A.;et al. An analysis of the Ap binary HD 81009.
February 12, 2001. Preprint No. 2001-0004