Here at the University of Hamburg
research in astronomy is carried out here at the observatory.
For the largest part of humanity.
people have looked at the skies and observed stars and planets in optical wavelengths.
This means light that we can see with our eyes.
Over the past decades, astronomers have started to use all kinds
of electromagnetic waves from the x-rays, gamma rays, microwaves, infrared waves to look at the sky.
And this is shown a whole new side of the universe.
And this is what we're going to talk about today.
Hi. My name is Amanda Wilbur, and I am a Ph.D.
student at the Hamburger Sternwarte with the University of Hamburg.
And today, we're going to talk about LOFAR radio astronomy and my research, which is on galaxies.
This might not look like a telescope, but essentially it is.
It's part of a large array.
What you see here is part of the largest digital radio telescope in the world.
It's called LOFAR a sense, the low frequency array.
It's essentially a digital camera for the sky.
This station is roughly the size of a football field, and it has about 200 antennas on them.
And these antennas record the radio waves that come from the sky.
Radio astronomy is a lot different than normal optical astronomy,
with telescopes that use mirrors or reflectors Radio images show us something that we cannot see with optical.
It's a different wavelengths of light.
This science is very new and cutting edge and on the frontier. LOFAR is an international collaboration.
And the University of Hamburg is part of this collaboration.
This frequency range corresponds to a wavelengths of light, which is about three metres long.
So we need multiple antennas to create one large telescope.
It consists of 51 of these kind of stations that you see here.
We mimic the action of a radio telescope that has the size of all of northwestern Europe from Ireland
all the way to southern Germany, from Sweden to France and from the Netherlands to Poland.
That's the extent of the entire LOFAR range.
The thickness of that received at
all the stations are then fed through cables underground and these cables are fed into this container.
This container is full of electronics, full of computers, and then the data is fit to a supercomputer
that is located in Groningen in the northern part of the Netherlands.
It's very important to know when the data was taken.
So a timestamp is crucial.
This is important because we need to create delays from different antennas when we want to point in a specific part of the sky.
So if we want to use this station in sync with the station in Ireland, for example, we need to know exactly
when the observation was made at this station and when the observation was made in Ireland so that we can synchronise the data
So this is what a typical LOFAR observation might look like.
This is part of a survey over the whole northern sky, and this is a very large area in the sky, five degrees.
And we can see many radio sources in this image.
So I took this image and I focussed on one source in specific that we've not seen here before.
It was very interesting and looking quite strange.
So if we zoom in on it, this is a preliminary image.
It's kind of a lower resolution.
We want to make it sharper and higher resolution so we can really do some science on it.
When we look at the galaxy with an optical telescope, we mostly just see starlight,
but if we use a radio telescope, we can see much more energetic phenomena such as the processes of black holes.
So the final image looks like this.
What we're looking at here is a galaxy cluster.
That means it's a group of galaxies that are bound together.
There are thousands of galaxies here. And what we can see is this optical image.
And every point in this image is a galaxy. The blue halo that we see is X-ray emission coming from the hot gas in between the galaxies.
That's at the centre of the cluster.
And the red emission is the radio emission that we see with LOFAR.
We can see an individual galaxy, an optical here, and it just looks like a dot.
It's all the starlight that's coming from the stars inside the galaxy.
But when we look at this same region of the sky with radio, we see a giant radio jet coming out of the galaxy.
This is being produced by a supermassive black hole inside of the galaxy.
And the jet itself is so long, it extends for 4 million light years.
That's almost the same size as a whole cluster of galaxies.
So we need telescopes
like LOFAR to see what other things are happening, what other energetic phenomena is happening in our universe.
Radio astronomy allows us to open a new window on the universe and see structures that we weren't able to see with normal telescopes.
I'm really glad that I was given the opportunity to come here because I am able to carry out my own independent research
doing observations with the LOFAR radio telescope and I get to discover new things that have never been seen before by anyone else.
LOFAR
and astronomy as a whole, takes place mostly in large international collaborations.
As important for the University of Hamburg to engage in these big collaborations and take a leading role in LOFAR.
Projects such as these allow us to do cutting edge research
and attract students from all over the world to do their research and lead independent research projects here in Hamburg.
Ich hoffe, das war interessant. Tschüs!