W3(H2O) at 22GHz

[Michiel Klaassen]

Hi All,

I am writing up the measurements we have done with the Sao Giao radio telescope  for the parac site.
First:
W3(H2O) see figure xx1.  Integration time is difference in index numbers X5 minutes.
We do not have a calibrated scale yet, so it was assumed that we just take the average of the published values. That seems to work for the methanol profile of W3(OH), but not for W3(H2O). 

We made a graph of some published data see xx2 and were forced to calculate the log value in a graph, because the differences are high and would not fit the graph. We found peak values ranging from 490 to 30902 Jy. Perhaps there is a cadence, but for now we assume that the latest 2013 value of 490Jy could be best.
But why is it so variable. It seems that W3(H2O) is a different region; see figure xx. So while W3(OH) is a simple cloud, W3(H2O) is further in its evolution and is forming a disk already and erupts polar outflows. see figure xx3
When looking at the measured curve it is different to the gathered profiles at www.maserdb.net. In our graph the top is not pointy at the peak, but more flat; consisting of several peaks. This could indicate multiple slow rotating clouds.  

Michiel
parac.eu

[Eduard Mol]

Hi Michiel,

Nice work, well done! 

Last month I also did some observations of the W3 star forming region at 22.2 GHz with the 1-metre dish. Surprisingly, my spectra look quite different from yours. There was a strong peak at -36 km/s and a few weaker peaks at -38, -41 and -44 km/s. I could not detect any emission near -48 km/s. Initially, I thought that frequency or Vlsr calibration was off. Alternatively, I was receiving another source within the 1.2- degree wide beam of the dish (there is another strong water maser source in the W3 region associated with the W3(2) infrared source). New observations of the W3 region were done on October 22. This time the dish was repeatedly pointed at the sources W3(OH) and W3(2). These sources are about 20 arcmin apart, which is less than the beamwidth of my small dish but still enough to make a measurable difference. Again, no emission was detected near -48 km/s. Furthermore, the peaks at -36 and -38 km/s were clearly stronger when the dish was pointed towards the position of W3(2). 

Maybe the W3(H2O) source near W3(OH) is just not strong enough to be detectable with my small dish. The Sao Giao radio telescope is of course much larger, so you could easily detect it. However, the beam width of the SGRT is also much smaller, so it is not detecting the W3(2) source at the same time when it is pointed at W3(OH). 

--
Je hebt dit bericht ontvangen omdat je bent geabonneerd op de groep 'Camras-forum' van Google Groepen.
Als je je wilt afmelden bij deze groep en geen e-mails van de groep meer wilt ontvangen, stuur je een e-mail naar camras-forum...@googlegroups.com.
Ga naar https://groups.google.com/d/msgid/camras-forum/CAABBjRCZ5dLcvjtzoErH292dO8qsHN5ACLUp2vHgSKyesEt2gA%40mail.gmail.com om deze discussie op internet te bekijken.

[Michiel Klaassen]

Hi Eduard,
Like a tourist, I just take radio pictures as much as possible and then in NL I see what I could have seen in real time.
So it appeared that the scales of two graphs were swapped. With the correct scale the mean peak appears now at -37km/s.
This indicates that the source is W3 IRS5.
The location was found when I just let the telescope (automatically) circle the pointed spot, because I lost a week trying to find W3(H2O).
As they say; big dish, big problems.
Studying at the university?; same subject or astronomy.
Michiel
parac.eu

Ga naar https://groups.google.com/d/msgid/camras-forum/CAFcm1Q7sLHWOVZJsUHzPquUu_aipkHSLKraWOJuDO53e3qtBnA%40mail.gmail.com om deze discussie op internet te bekijken.

[Eduard Mol]

Hi Michiel,

Now our spectra look a lot more similar. So we both detected W3 IRS5, but the W3(OH) H2O maser remains elusive...

With the small dish at home pointing is much less difficult, and I can always do observations whenever I have time and the weather is good enough. 

Ga naar https://groups.google.com/d/msgid/camras-forum/CAABBjRCz%2ByeJ80ucKLcGf9weFg9WLYtLv7Dvv3zobG1SMqDuFw%40mail.gmail.com om deze discussie op internet te bekijken.

[Michiel Klaassen]

All,

So, I accidentally swapped two x scales from different days.
When corrected we see that the main peak lies on -37km/s and not on -49km/s.
This means that the source cannot be W3(H2O), so it must be W3(IRS5).
This also explains why there is a plateau and not a peak.
Now the data results of Eduard and I match.

Because I could not find W3(H2O) in the first place, I searched in circles around the given location. This was done automatically of course for some hours.

I will try the same procedure to make an estimate of the intensity scale.

Another interesting thing is that although the top is almost flat, in the literature sometimes a narrow peak stands on top of the plateau.
Because it is very narrow, it is easily averaged and disappears. I will re-examine the data to see if a narrow peak can be isolated;  perhaps by correlating consecutive time lines.
Fun and learning all the time.

Michiel
parac.eu

[Michiel Klaassen]

All,

When re-examining the data and now showing also the power values above the average (graph bleu) values, then you get graph b.

Note that to the far left and far right side both graphs have the same value.
These are the silent parts; they just display the average nois; no change.

In the middle you see that the green graph is elevated, and shows peaks.

In my opinion this shows that there are peaks coming from the source.

However with our simple amateur equipment we cannot enhance them in a standard way.

I will put the raw data also on the website, so if you want, you can also struggle with it.
As a reference enter W3IRS5 in google and also in maserdb.net

Have fun with the hobby, and I hope I did not annoy you too much with my posts.
Michiel
parac.eu

On Tue, Nov 8, 2022 at 2:43 PM Michiel Klaassen <vmin...@gmail.com> wrote:

W3 IRS5 sent a selfie

On Tue, Nov 8, 2022 at 9:23 AM Eduard Mol <eddiem...@gmail.com> wrote:

Hi,

Now I see the post with my results was only sent to the CAMRAS list and not to the SARA list

So, here are my spectra of the W3 region. Both W3(H2O) and W3 IRS5 are within the 1.2 degree wide beam of my 1-metre dish. To figure out which of the sources was detected, I pointed the dish at the positions of W3(H2O) and W3 IRS5. These two sources are only 20 arcmin apart, considerably less than the beamwidth of the dish but enough to make a measurable difference. A relatively strong signal was detected at -37 km/s, with some weaker peaks at -38- -41 km/s. The peaks at -37 and -38 km/s were clearly stronger when the dish was pointed at the position of W3 IRS5. No emission was detected at the expected LSR velocity of W3(H2O) at -48 km/s.  

--

Je hebt dit bericht ontvangen omdat je bent geabonneerd op de groep 'Camras-forum' van Google Groepen.
Als je je wilt afmelden bij deze groep en geen e-mails van de groep meer wilt ontvangen, stuur je een e-mail naar camras-forum...@googlegroups.com.

Ga naar https://groups.google.com/d/msgid/camras-forum/CAABBjRAYwiR8eD7ttcEkF8Z68EqNMcKD-Xi8fP4Jz0hw9U0dyA%40mail.gmail.com om deze discussie op internet te bekijken.

--
--
You received this message because you are subscribed to the Google
Groups "Society of Amateur Radio Astronomers" group.
To post to this group, send email to sara...@googlegroups.com
To unsubscribe from this group, send email to
sara-list-...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/sara-list?hl=en
---
You received this message because you are subscribed to the Google Groups "Society of Amateur Radio Astronomers" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sara-list+...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sara-list/CAFcm1Q7oOk7-RNSumn6Y9rPRjzC1UeXUB%3DrNLJmotRwfJ2pXZA%40mail.gmail.com.