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Author Topic: Peas Project  (Read 24645 times)

Rick Nowell

Re: Peas Project
« Reply #495 on: September 29, 2008, 12:22:38 pm »
Quote from: Alice on September 27, 2008, 05:10:44 pm
Want me to put the peas into the peas thread, folks? I'd be happy to. :)

It might be a good idea, as that would seem to be their natural home. Otherwise, interesting developments
could get lost in the 'crowd'.
Is someone going to start a new pea topic in GZ2- perhaps stick them in there?

Quote from: zookeeperKevin on September 27, 2008, 07:12:02 pm
I think Carie has now finished analysing the spectra, so we can now start plotting things.

Does this mean any 'problems' with Gandalf not recognising AGNs has been overcome? Plot away...
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@kim78

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Re: Peas Project
« Reply #496 on: September 29, 2008, 01:20:28 pm »
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zookeeperKevin

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Re: Peas Project
« Reply #497 on: September 29, 2008, 03:12:19 pm »
Quote from: Rick Nowell on September 29, 2008, 12:22:38 pm
Does this mean any 'problems' with Gandalf not recognising AGNs has been overcome? Plot away...


We had to do some modifications to GANDALF and the peas need quite a bit of hands-on attention during fitting.
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ccardamone

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Re: Peas Project
« Reply #498 on: September 30, 2008, 01:48:13 pm »

Does this mean any 'problems' with Gandalf not recognising AGNs has been overcome? Plot away...
[/quote]

Hey sorry to be so long between postings - I should explain my thesis is a separate project and I'm working on the Peas for fun (because they are so cool!!) but sometimes that means I don't get as much time to play with them.

We've massaged gandalf (with the code's authors help) to not reject our AGN.  There are several cases, where it just won't fit the emission lines at all.  But I think we're doing OK on the rest of the sample.  Most of the one's we fail to fit just have spectra that are too faint.  I fit each spectra by hand, twice.  So thats what caused this very long delay . . .

I'm working on extracting the results now and I hope to post more information soon (ie. next day or two).

Thanks for all your help!
Carie



« Last Edit: October 02, 2008, 02:41:36 pm by ccardamone »
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ccardamone

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Re: Peas Project
« Reply #499 on: October 02, 2008, 01:20:02 pm »
Hi All,
   Here is my plot with the new improved spectra fits.  We still don't have nearly as many AGN as I expected.  There are a total of ~12 in the sample (8 fit on the plot, the others are off to the north) and a few more (9) transition objects on the line between star bursts & AGN.   The rest seem to be star forming objects (102 of them).  The star formation rates I've derived are incredibly large (10s - 100s of Msun / year).  I'm going to have to look into how well I think we've calculated them. 

Three of the sources which fall in the Starburst catagory have X-ray luminosities which label them as likely AGN.  The diamonds on the plot are X-ray sources.

This all bears some more thinking about . . .



 
« Last Edit: October 02, 2008, 01:21:33 pm by ccardamone »
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FermatsBrother

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Re: Peas Project
« Reply #500 on: October 02, 2008, 02:18:13 pm »
Quote from: ccardamone on October 02, 2008, 01:20:02 pm
Hi All,
   Here is my plot with the new improved spectra fits.  We still don't have nearly as many AGN as I expected.  There are a total of ~12 in the sample (8 fit on the plot, the others are off to the north) and a few more (9) transition objects on the line between star bursts & AGN.   The rest seem to be star forming objects (102 of them).  The star formation rates I've derived are incredibly large (10s - 100s of Msun / year).  I'm going to have to look into how well I think we've calculated them. 

Three of the sources which fall in the Starburst catagory have X-ray luminosities which label them as likely AGN.  The diamonds on the plot are X-ray sources.

This all bears some more thinking about . . .

Hi ccardamone - How do you manage to extracate the NII peaks from the H(alpha) peaks to calculate your NII/H(alpha) ratios ?
It appears that often there is a major overlap. Perhaps you have some cunning software ? ;D

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Alice

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Re: Peas Project
« Reply #501 on: October 02, 2008, 02:27:50 pm »
Can I be thick and ask for a key to your graph, Carie? For example, what the small red crosses are. Thanks :)
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ccardamone

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Re: Peas Project
« Reply #502 on: October 02, 2008, 02:38:53 pm »
Quote from: Alice on October 02, 2008, 02:27:50 pm
Can I be thick and ask for a key to your graph, Carie? For example, what the small red crosses are. Thanks :)

Sorry!!

I just color coded the points based on where they fell in the graph.  If they were in the Starburst area, I colored them red, the AGN area I colored them Blue.  There are 2 different published selections for the line between SB and AGN, so I put points in between the 2 in Green.
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ccardamone

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Re: Peas Project
« Reply #503 on: October 02, 2008, 02:41:08 pm »

Hi ccardamone - How do you manage to extracate the NII peaks from the H(alpha) peaks to calculate your NII/H(alpha) ratios ?
It appears that often there is a major overlap. Perhaps you have some cunning software ? ;D

Fermats Brother


I used a soft ware suit named Gandlf, which was developed by a group of Astronomers in the Sauron Survey.  (http://star-www.herts.ac.uk/~sarzi/PaperV_nutshell/PaperV_nutshell.html)
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FermatsBrother

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Re: Peas Project
« Reply #504 on: October 02, 2008, 02:50:38 pm »
Quote from: ccardamone on October 02, 2008, 02:41:08 pm

Hi ccardamone - How do you manage to extracate the NII peaks from the H(alpha) peaks to calculate your NII/H(alpha) ratios ?
It appears that often there is a major overlap. Perhaps you have some cunning software ? ;D

Fermats Brother


I used a soft ware suit named Gandlf, which was developed by a group of Astronomers in the Sauron Survey.  (http://star-www.herts.ac.uk/~sarzi/PaperV_nutshell/PaperV_nutshell.html)

Hi ccardamone - So, what are the errors associated with your NII/H(alpha) ratios ? (+/- 50% ?) ;D

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ccardamone

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Re: Peas Project
« Reply #505 on: October 02, 2008, 03:48:05 pm »
Quote from: FermatsBrother on October 02, 2008, 02:50:38 pm
Hi ccardamone - So, what are the errors associated with your NII/H(alpha) ratios ? (+/- 50% ?) ;D
Fermats Brother

I plotted all points where the S/N ratio was higher than 3.  The errors are a bit more complicated because it is also a function of how well the template fits the spectrum.  I'd say they are good to at least 50%.

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Rick Nowell

Re: Peas Project
« Reply #506 on: October 02, 2008, 07:44:06 pm »
Quote from: ccardamone on October 02, 2008, 01:20:02 pm
Here is my plot with the new improved spectra fits.  We still don't have nearly as many AGN as I expected.  There are a total of ~12 in the sample (8 fit on the plot, the others are off to the north) and a few more (9) transition objects on the line between star bursts & AGN.   The rest seem to be star forming objects (102 of them).  The star formation rates I've derived are incredibly large (10s - 100s of Msun / year).  I'm going to have to look into how well I think we've calculated them. 


Very few AGNs- roughly 10%. So what is driving so much star-forming? The formation rates are incredibly high- I hope your calculations
confirm your preliminary findings and that it all bears thinking about. 
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ccardamone

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Re: Peas Project
« Reply #507 on: October 02, 2008, 08:39:46 pm »
Quote from: Rick Nowell on October 02, 2008, 07:58:50 pm
I took the liberty of capturing your graph Carrie. I hope you don't mind...

thats great - thanks.
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zookeeperKevin

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Re: Peas Project
« Reply #508 on: October 02, 2008, 10:05:53 pm »
Wow, I am really surprised at the large starforming number. Carie -- can you check if any objects with broad lines are classified as SF?
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Rick Nowell

Re: Peas Project
« Reply #509 on: October 03, 2008, 09:27:39 am »
Link to a very early galaxy, the 'Baby Boom' galaxy, which is a starburst with star-forming rates of up to 4000 a year.
http://www.spitzer.caltech.edu/Media/releases/ssc2008-12/release.shtml
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