Astrophysics
Areas of special interest: Galaxies, galaxy formation and Supermassive Black Holes.
Australian Astronomical Observatory (2015)
More about this soon!
Mount Wilson Observatory (2014)
In the summer of 2014 I spent two weeks on historic Mount Wilson Observatory as a part of the CUREA summer program in Observational Astronomy. The program was divided into two parts: The first week we learned different observational techniques (photometry, spectroscopy, imaging) and got to see a variety of day time and night time telescopes at Mount Wilson Observatory. The second week we did a research project of our own.
Mount Wilson is where Edwin Hubble discovered that the Universe is expanding when measuring the recessional velocity of galaxies, thus the perfect place to study galaxies. In my research project I studied M31, the Andromeda galaxy. I photographed the galaxy using a DSLR camera to get RGB colors directly, instead of photographing each filter separately with a CCD camera. The setup was a Canon EOS ("Rebel") DSLR with the infrared-blocking filter removed on a Meade 80 mm APO refractor with a field flattener yielding an effective focal ratio of f/5.4 and a field of view of approximately 3x2 degrees. I took 8 minutes exposures. Original vs. photoshopped image (click to see larger version):
Mount Wilson is where Edwin Hubble discovered that the Universe is expanding when measuring the recessional velocity of galaxies, thus the perfect place to study galaxies. In my research project I studied M31, the Andromeda galaxy. I photographed the galaxy using a DSLR camera to get RGB colors directly, instead of photographing each filter separately with a CCD camera. The setup was a Canon EOS ("Rebel") DSLR with the infrared-blocking filter removed on a Meade 80 mm APO refractor with a field flattener yielding an effective focal ratio of f/5.4 and a field of view of approximately 3x2 degrees. I took 8 minutes exposures. Original vs. photoshopped image (click to see larger version):
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I also photographed 6 stars of different spectral classes to make my own color index for the DSLR camera so that I could determine which star populations are present at various locations in M31. I split the star images into R, G and B only images and measured the color index of each star, [B–G], [G–R] and [B–R], shown in the figure to the right.
Then I split the image of the galaxy into R, G and B only images, chose a small measuring area of 41 x 33 pixels and measured the intensity in 10 locations in the galaxy for the different filters, resultings in values Gal_B (blue) and Gal_G (green). I also measured a completely dark area of the image so that I could subtract the sky background, resulting in values Sky_B, and Sky_G. Then the [B–G] color index for the different locations in the galaxy could be found by: The values found at different locations in the galaxy is shown in the image to the right (click on it to see a larger version). We can then locate these values in the plot to see what kind of stars are present. Doing this we see that the core with [B–G] = 0.36 consist of F stars, the edge of the core and the mid disc has A stars, while the outer disc has B stars. This means the core is redder and the outer edges are bluer, consistent with what one would expect. The spectral types are in reality shifted more towards the red than what I found with this simple procedure, using rather few reference stars.
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We also photographed M57, known as the Ring Nebula (left) in three filters, took the spectra of stars of various stellar classes (I was responsible for the G-star Eta Boötis and the M-star Lambda Draconis) and observed the variations in intensity from a variable star, RR Lyrae.
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Main image: Galaxy M106 (source), a Seyfert II galaxy.
