Astronomer of the Month: Tomas Dahlen

Each month we will highlight a member of the CANDELS team by presenting an interview introducing them and what it's like to be an astronomer. This month's Astronomer is Tomas Dahlen.

Tell us a little about yourself!

My name is Tomas Dahlen. I'm an Associate Scientist at Space Telescope Science Institute in Baltimore, MD, where I'm been for about six years since moving from my native Stockholm, Sweden. 

What is your specific area of research? What is your role within the CANDELS team? 

I'm a co-investigator in the CANDELS team. I'm particularly interested in the supernova aspect of the survey, deriving rates of both Type Ia supernovae and core collapse supernovae and figuring out what they can tell us about for example the history of star formation and metal enrichment. I'm also involved in deriving photometric redshifts to the galaxies in the different fields.

What made you want to become an astronomer? At what age did you know you were interested in astronomy? 

Some of my earliest memories in life are associated with the Apollo program. I remember watching the landing on the Moon and playing with those space age toys and listening to "Major Tom". I think I've always kept that fascination for space and astronomy, but didn't for a long time imaging that it was something that I could actually work with. I graduated with a Masters of Science in Physical Engineering from the Royal Institute of Technology in Stockholm, not including any courses in astronomy. However, I did take a course in special relativity which was nice. It wasn't until my early 30s that a took a couple of evening courses in astronomy that I realized that this could actually be something to make into a career. So I took a full year of undergraduate course and thereafter started my PhD studies at the Stockholm Observatory. I completed my PhD in 2002 and went for a first Post-doc at STScI working with the GOODS collaboration. After a second Post-doc, this time in Stockholm, I went back to STScI 2006 and has been there since.

What obstacles have you encountered on your path to becoming an astronomer and how did you overcome them? 

I think that the uncertainty of the job situation after getting a PhD is an obstacle that many have to struggle with. You spend many years on studies and then Post-docs not really knowing if and when you will be able to get a more permanent position down the road. This can be hard, but so far I've been lucky to be able to find work at places I really like.

Who has been your biggest scientific role model and why? 

No one really specific I guess. But after taking that early course in relativity, I've been fascinated and intrigued about the thought processes that must have been going around in Einstein's head.

What is it like to be an astronomer? What is your favorite aspect? 

It is of course very nice to work on something that you really like. And you are at times trying to help answer questions that have yet been answered. That's a nice thought. And it takes you places all around the world when collaborating with other scientists, making your own observations, or attending conferences.  

What motivates you in your research? 

This is related to above, finding out just a small bit of the big picture.  

What is your favorite astronomical facility? (This could include telescopes or super computers, for example) 

Having worked with the remarkable Hubble for a number of years, this has to be my favorite. Of telescopes that I've actually touched, the Nordic Optical Telescope on La Palma has a special place since I spent numerous nights there during my PhD. And of course also the retired 50/60cm diameter, 8 meter focal length, Double Refractor telescope from 1930 at the Observatory in Saltsjobaden in Sweden. I held a series of public shows at this telescope during the winter months in the mid 90's. Boy were people surprised when the dome floor started to move up or down when the telescope changed position and found it hard to believe that it was actually Saturn with its rings they were looking at and not an image someone had put in the telescope.

Where do you see yourself in the future? What are your career aspirations? 

I hope to continue working within the field, including inspiring collaborations such as CANDELS.
 

If you could have any astronomy related wish, what would it be? 

To find something no one had expected in the next CANDELS supernova search.

What is your favorite, most mind-boggling astronomy fact? 

Just the mere size of space and time is amazing. The light packet from a distant exploding supernova has been traveling for many billions of years when we detect it with Hubble, a few weeks later it is gone.

Is there anything else you would like for the public to know about you or astronomy in general? 

When I am not working on astronomy, I take my telescope outside; but not for star gazing at night, but rather birding any time of the day. I've been a devoted birder my whole life and combining this with the possibilities to travel that the profession as an astronomer gives, provides great opportunities to visit and bird different parts of the world.