The best galaxy pair yet…
Fresh off the telescope, I wanted to share with you this spectacular spiral-spiral pair. Both of these galaxies probably look alike, but we’re seeing one edge on, and the other face on. (The bright thing on the left is a star, surrounded by reflections we haven’t had time to remove yet). The bright knots you can see in the face-on galaxy are likely to be bright star clusters, probably of young stars. Not only does this system look good, though, it’s pretty much ideal for our project. The edge on galaxy is clearly behind its face on neighbour (and these two are close together), whose spiral arms run in front of it. It’s also nice and smooth, so we can predict what light will hit the nearer galaxy – and use that to deduce its dust properties.
A couple of peculiar galaxies before bed
It’s been a bit busier tonight; small problems with the software to deal with, and a group of migrant astronomers wanting help with their telescope among other things. In the meantime, here are the two most interesting objects of the night’s crop. 
Goodnight all.
Two kinds of sound
Just before tonight’s observations began, I managed to record a quick interview with Bill. The background noises you can hear are the sounds of a telescope being rapidly prepared for action; listen very carefully and you’ll hear the ‘beep’ of the slewing telescope up in the dome.
[audio:http://chrislintott.net/Audio/BK_Day2_2.mp3%5DWe’ll try and do the same tomorrow, and if you have any questions for Bill (or Anna or myself) post them in the comments and we’ll do our best to answer
In the meantime, we’ve resorted to music to keep us all awake. As discerning people with eclectic tastes, we’ve resorted to attempting to compile a relevant playlist. If you can help us get beyond this, we’d be most grateful.
Touring the telescope
While Bill is once more pointing the telescope at the wall (in order to measure the noise in the camera), I thought you’d want to see the telescope that’s providing us with our beautiful images. The WIYN 3.5 m is the most modern of the big telescopes up here, and was opened for business in the mid 90s; as you can see from the image below, it has a very unusual and distinctive structure.
Read More…
Breakfast
It’s 2pm local time, and I’ve just managed to drag myself out of bed ready for our second night’s observing. During the day Kitt Peak is essentially a tourist destination; I just popped into the visitor’s centre to buy some water and found the third tour of the day getting briefed before setting off up the mountain. There’s also a public sky viewing program in the evenings, and they even rent out some of the smaller (but still substantial) telescopes on the mountain to anyone who wants to use them. It’s still sunny, and it won’t be long before we have to start preparing the telescope, but for now more prosaic thoughts dominate. Breakfast time…
P.S. If you want to follow our exploits in more detail this evening, we’ll be updating the newly established WIYN twitter feed.
First images on the fly
Unbelievably, it’s already 2am on our first night on the mountain. Things are going pretty well; the seeing has improved somewhat and so far the camera seems to be performing well. More importantly, I’m managing to stay awake despite a bit of a slump for an hour and half – it turns out pots of coffee are the solution.Of course, this is just the start of the hard work. Behind me, Anna (a PhD student from the University of Alabama) is working hard at not swearing at the computer in the course of analysing the data properly; a painstaking process which we’ll describe in more detail later in the week. Meanwhile, to my left Bill is invoking supervisor’s privilege and doing a rough version of the same analysis. First results visible by clicking to read more.
On sky…
Well, it’s dark (although only just by astronomical standards). If you don’t believe me, then you can keep an eye on the all sky camera.
We’ve just headed over to our first object, which is the galaxy below.

As you might remember we’re investigating the Galaxy Zoo sample of overlapping galaxies. This is a fairly typical example; an apparently smaller galaxy (the round blob on the left) hiding behind a larger one. In fact, we know from Sloan’s measurement of the spectra of each of these objects that the blob on the left is more distant than its apparent neighbour. In fact, the distant galaxy is 1.6 Billion light-years away, and the closer one is ‘only’ 220 Million light-years distant. Our first trial image is up on Bill’s screen next to me now, and it looks reasonable. Although the weather is perfect – it’s completely clear – the seeing is pretty poor. Seeing is how astronomers measure the wobbling of the Earth’s atmosphere above us; that’s our main complaint so far. Still, the night and the week are young and it’s great to be on sky following up Galaxy Zoo for the first time.
Top of the mountain to you
Made it! This post is being written from the WIYN telescope control room. It’s 4pm local time, the Sun is still high in the sky and the first exposure of our observing run has been made. No, we haven’t gone mad, and I haven’t forgotten that this is an optical rather than a radio telescope; our first task has been to take ‘flats’; images of the observatory dome to understand the behaviour of the camera set up. Meanwhile, Bill is flipping through the big red book of overlapping galaxies to find our first targets for the night. Let me show you around a little; here’s the view from just outside the door, looking away from the observatory

and here’s us, viewed from the other side of the mountain. The dome in the foreground is the 0.9m SARA telescope, and the hexagonal dome in the distance is WIYN.

Despite being in the desert, one surprising thing is the abundance of (albeit scrubby) vegetation on top of the mountain; there’s enough rain to support it although it hasn’t rained for a month or two. The sky is clear if a little hazy, so fingers crossed. This was the first big observatory site I visited, as a tourist just after I’d started my undergraduate degree, and it’s wonderful to be back as something approximating a fully fledged astronomer. More soon…
Speaking of mergers…
Just as we have all been examining and testing for merging galaxies within Galaxy Zoo, the folks at Hubble have released a catalog of beautiful pictures of 59 pairs of merging galaxies. Take a look at the images – some of them are really beautiful, and they make an interesting contrast with the SDSS images that Galaxy Zoo uses. The SDSS is a survey, so see everything we can see, and the Hubble Space Telescope is a queue-based observing telescope, meaning it gets images one-by-one of interesting objects.
Frank Summers, the visualization genius at the Space Telescope Science Institute, has produced some great animations to go with the merging galaxies catalog release. The animations really help you get a sense for how scientists go about using computer simulations to study merging galaxies. It’s a tricky business, because there isn’t a one-to-one relationship between where two merging galaxies start from and where they end up – mergers that look the same can result from vastly different circumstances. The best way to study mergers is to look at a lot of them to find similarities and differences – which is exactly what you’re doing with Galaxy Zoo!
Why Are Mergers Important?
What will we use our merger data for?
Mergers are really interesting since they are the main process by which the universe evolves its galaxy population and creates more and more massive galaxies. Additionally, the collision between two galaxies involves ALOT of energy. This energy gets transferred into compressive forces when clouds of gas in the galaxies collide and collapse into violent bursts of star formation. Understanding how all the stars in the universe form is a really important aspect of a full understanding of the cosmos and so mergers help us understand some of the key observations made in modern astronomy. We also want to know what fractions of mergers involve spirals and how many are ellipticals, what is the typical mass ratio between merging galaxies and whether or not mergers tend to happen in clusters or not.
Another important contribution mergers can make is help us understand the formation of Active Galactic Nuclei (AGN). Mergers and, more generally, galaxies with disturbed morphologies often turn out to be Ultra-Luminous-Infra-Red Galaxies (ULIRGs) which are themselves interesting because they tend to host AGNs. An AGN is thought to be a Super Massive Black Hole that sits at the centre of a galaxy and produces vast quantities of radiation as matter falls into it (this is called ‘accretion onto a black hole’). AGNs produce vast amounts of light that far out strips that emitted by all the stars in its galaxy combined. Also, they sometimes produce dramatic jets of matter that fly out at relativistic speeds. Alot is still unknown about the mechanism that produces these jets and so AGN and their formation is a hot-topic of research. Distant quasar galaxies are thought to be AGN and tell us much about the formation of the first galaxies in the universe. The more we know about AGN and how they form, the more we can know about some of the distant events near the beginning of the universe. Specific properties of AGN can be probed by examining the spectra that they produce and we hope to apply these tests to all of the good mergers that we find.


