Excitement of Science 2009

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Map of the sky

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1 Map of the sky on Wed Mar 04, 2009 12:49 am

[url]http://www.jb.man.ac.uk/distance/observatory/data/eos-radiosky.html[/url]

Is it just me, or is there a really strong source, right next to a fairly weak one? Any Ideas?

P.s anyone know how to use the url link tags?

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2 Re: Map of the sky on Wed Mar 04, 2009 1:15 am

I am hoping that the source is from the scan that we did (e091, Gal Lon 118). This was scheduled for 8.50pm last night but didn't happen due to the high winds. I re-tried this morning at 6am but the schedule didn't show it. The monitor tool from JB suggested it worked though.

Just tried the url link tool. I have used these before on other forums. This one doesn't seem to work (in the same way.)

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3 Re: Map of the sky on Wed Mar 04, 2009 2:58 am

[quote="socrates"]I am hoping that the source is from the scan that we did (e091, Gal Lon 118). This was scheduled for 8.50pm last night but didn't happen due to the high winds. I re-tried this morning at 6am but the schedule didn't show it. The monitor tool from JB suggested it worked though.
[/quote]

Hi Socrates, After you've set up your observation you need to click the Submit button the Schedule page. Look on Schedule page you'll see your observations from this morning have big red exclamation marks. It means they've not been queued - this was to allow people to delete observations because they'd picked the wrong year or month or something.

cheers
Tim

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4 Re: Map of the sky on Wed Mar 04, 2009 3:01 am

[quote="mark"][url]http://www.jb.man.ac.uk/distance/observatory/data/eos-radiosky.html[/url]

Is it just me, or is there a really strong source, right next to a fairly weak one? Any Ideas?
[/quote]

OK now we are getting a few observations coming in you can start to think a little about what the data are showing and discuss it with your students.

Look for interesting features in the emerging image. Have a look at neighbouring scans in the image for example (as you mention in your posting quoted above). Look at the actual data by clicking on the Data button for that scan in the Archive page. Compare one scan to another. Look at the brightness levels - are they roughly consistent or are there large deviations?

Cheers
Tim

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5 Re: Map of the sky on Wed Mar 04, 2009 7:41 am

On the comparing brightness, temperature etc of other peoples data, I'm starting to think we've done our scan wrong....

Our temperatures are between 270 and 290 degrees Kelvin, which I believe to be basically 0 to 20 degrees celcius, or approx room temp... I think we messed it up.

As for looking at the bigger picture, the brightest spots are all definitely in the middle, and as my friend pointed out, since we're taking scans perpendicular to the milky way, the bright white bits are looking straight into the Milky Way, which is cool.

[quote]OK now we are getting a few observations coming in you can start to think a little about what the data are showing and discuss it with your students.[/quote]

I am a student =)

cheers,
e092

P.s I thought I'd have a second go at the Url...

[url]http://www.jb.man.ac.uk/distance/observatory/data/eos-radiosky.html[/url]

Nope, not worked =(

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6 Re: Map of the sky on Wed Mar 04, 2009 1:58 pm

[quote="tob"]
Hi Socrates, After you've set up your observation you need to click the Submit button the Schedule page. Look on Schedule page you'll see your observations from this morning have big red exclamation marks. It means they've not been queued - this was to allow people to delete observations because they'd picked the wrong year or month or something.

cheers
Tim[/quote]

Hi Tim

This morning the schedule page was stuck and not updating so I wasn't able to change to status 2. However, when I viewed the monitor it suggested that the scan was taking place. Can you confirm that the scan for source co-ords 118,0 appears on the EOS-Radiosky image?

Thanks.

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7 Reading the Graphs! on Wed Mar 25, 2009 2:40 pm

[b]Does anyone have the foggiest idea how you read the graphs?[/b] We're guessing the high and low peaks are high and low readings of radio waves measured in K, but is there anything we are missing? We are sort of at a dead end, as the only teacher who would possibly know was it says hasn't a clue, so at the moment we are a bit stuck.
Can anybody shed any light onto the problem?

Thanks!
[b]e050[/b]

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8 Re: Map of the sky on Thu Mar 26, 2009 11:07 am

Which graphs? The normal EOS scan, or the Spec scan?

For the EOS scan, as far as we can tell, the high points are hotter temperatures, though we havent managed to get two graphs with the same temperatures yet... The hotter the temperature, the denser the area of sky, so we tried to guess what we were looking at through that.

In the spec scan, we noticed that we had some very specific spikes, which correspond to different wavelengths, and thus different elements. However, we had 3 definite spikes at differing frequencies, but they all had a wavelength of 21cm to within a couple of mm. So were still struggling as to why there are 3 spikes, not one...

Hope that helps... =)

P.s for a couple of maps to compare the results against what you could be seeing;

http://mwmw.gsfc.nasa.gov/cgi-bin/mw/mw6_zoom2.pl?620,0;8

http://galaxymap.org/drupal/node/92

http://galaxymap.org/drupal/node/93

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9 Re: Map of the sky on Wed Apr 01, 2009 2:45 pm

Could the reason for the high density/heat be stars, all of the gas and space debris inside them could be quite dense and they are quite hot so could this be a reason?

Also could the extreme low temperatures be due to a black hole nearby or if black spots appear on scans could this also be due to black holes?

This is only a theory but if I could get some feedback on if it sounds feesable that would be great. My science teacher has been really buisy with GCSE marking so I haven't had time to ask him.

Thanks ^^

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10 Re: Map of the sky on Thu Apr 02, 2009 9:21 am

I doubt the really cold parts are black holes, especially as the really cold parts are only bout 60K less.

I dont think there are many black holes in the Milky way,if any more than the one in the centre of it, so I dont think the black spots are something else...

For tim or anyone else involved in the running,

Two questions, how come we can only scan part of the milky way (0 to 240), not 0 to 260, and is there anyway possible to scan 0 degrees because thats the interesting part =)

Thanks
Mark e092

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11 Re: Map of the sky on Thu Apr 02, 2009 2:44 pm

On the subject of black holes, the simple point of black holes is they dont have a temperature, they are one way, nothing can escape from there surface, not light (thus the name "black holes"), or IR (infared) aka heat. But Straight away anyone who knows the work of stephen hawking and or max plank and anything to do with "black body radiation", knows it is actually possible to say they have a temperature. Now the equation for this is (ħC³)/(8πkGM) Now using this i can say that a black hole of 30 solar mass (30 times the mass of the sun) has a temperature of 2.056709107 x10 -9 Kelvein. so close to 0 but obviously not because at 0 K matter stops E=mc2, 0 energy 0 mass. But there are black holes in our galaxy and they are very hard to spot unless they are interacting with something else, this as good as 0 point is so small it is massivly unlikely that they are being picked up in our scans

J Gannon
e092

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12 Re: Map of the sky on Wed Apr 15, 2009 8:21 am

Hi

To answer a few of these points:

The vertical scale on the scans is something called brightness temperature. Radio astronomers use it as a measure of brightness (signal strength). It is given in temperature units (Kelvin) because we say teh sigbnal is the same strength as would be given out by an object of that temperature. To explain further, you will know that as you heat a metal bar, say, it starts to glow and as it increases in temperature the colour works through the spectrum from red to blue. The spectrum produced by these sort of opaque objects is called a blackbody. Our bodies are at a temperature that means we glow in the infrared. Most stars are hot enough to glow brightly in the visible. However some things are so cool they glow most brightly in teh radio part of the spectrum.

Now, in fact, here we are looking at a combination of radio waves from electrons spiralling around in magnetic fields and from hydrogen atoms in interstellar space. So the temperature in this case doesn't correspond to a real physical temperature but is just a measure of the brightness.

You should now start to see the plane of the Milky Way Galaxy as the bright ridge running along the middle. Superimposed on it we're gradually starting to see brighter spots as the blanks get filled in. We may need to adjust the scaling on the map to see both bright parts and faint parts to get the best view. It is these bright spots that we'll look at later.

Now to answer the question about why a spectrum showed 3 peaks rather than just one. Here the main peak in the spectrum is from hydrogen atoms producing emission at a frequency of 1420.406 MHz (about 21cm in wavelength). You see 3 peaks near this frequency because there are 3 clouds of hydrogen atoms in that direction each moving a different speed relative to us. This means the peaks are doppler shifted to different frequencies. Clouds moving towards us are shifted to higher frequencies (blueshifted), those moving away to lower frequencies (red shifted). Try changing the horizontal axis to velocity to see what speed the clouds are moving at (negative velocities mean they're coming towards us).

In fact, although one observation can't prove this, the 3 clouds are actually the line of sight cutting through three spiral arms! One is teh local arm in which our Sun sits, so it's velocity relative to us shoudl be about zero. The others are more distant arms. With a series of these observations we coudl map out teh spiral structure of the Milky Way, but maybe we shuodl leave that to another day!

All the best,

Tim

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