Author Topic: Friday 16th January 2009  (Read 5361 times)

Rick Nowell

  • Hero Member
  • *****
  • Posts: 1333
  • Bristol, U.K.
    • View Profile
Friday 16th January 2009
« on: January 16, 2009, 12:38:03 am »
For my OOTD, I present a composite of 18 SDSS pictures into a montage I have named
'Markarian Peas'. For GZ forum aficianados, both terms will be familiar, although not
necessarily in the same title.



Firstly the Markarian bit. The First Byurakan Survey was made during the sixties at the
Byurakan Observatory in Armenia. From this, Benyamin Markarian extracted 1500
galaxies which were unusually bright in the ultraviolet. These galaxies are unusual in that
they appear very blue, with many of them being dominated by a bright nucleus. In short,
Markarian galaxies are vigorously active places, but no one is quite sure why, or in what
critical ways they differ from our own quiescent Milky Way.There are more than 200
Seyferts, dozens of QSOs, few hundreds of starburst and HII galaxies, BL Lac objects,
radio, IR and X-ray sources among them. The active star formation in Markarian galaxies
also makes them prime objects for infrared studies because the copious dust in these
regions emits strongly in the infrared.
This link takes you to the GZ topic: http://www.galaxyzooforum.org/index.php?topic=10047.0

So, these are well-known astronomical objects...What then are 'Peas'?

'Peas' are an unofficial title for objects that have a very high presence of OIII, or doubly-
ionised Oxygen. OIII has had two of its electrons stripped away because of massive energetic
activity taking place. The term was coined by Hanny here: 
http://www.galaxyzooforum.org/index.php?topic=3638.0   
and was at first, maybe still, humourously applied to objects that appeared green. These objects have
since become a subject though for serious study and hopefully a paper might appear which sheds
light on these green OIII objects. This is explained in greater detail here:
http://www.galaxyzooforum.org/index.php?topic=270633.0

More generally, all sorts of colours of Peas were found, the main criteria being that they should
have a massive 'spike' in the part of the spectrum where OIII is found. So, using this criteria
I made a list of Markarian objects that are available in SDSS; several hundred it turned out
and for view as an attached text. From that I extracted Peas- objects that had the OIII spike.
Then, I combined the ones I felt most beautiful in to the composite above. I hope you like it!
 A text containing who posted what is attached.

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Re: Friday 16th January 2009
« Reply #1 on: January 16, 2009, 12:52:52 am »
Peas that ceased to be green, and jokes that got increasingly serious . . . 8)

Supercool - thanks very much for this, Rick! ;D I'll be downloading those documents to have a proper look at them. The "peas" researchers are doing some amazing stuff; and Rick, besides a lot of meticulous contribution to the science, thank you for this lovely artwork to go with it.

Oh, and thanks for explaining the Markarian bit too. ;D
« Last Edit: January 16, 2009, 03:16:28 am by Alice »

Pat

  • Hero Member
  • *****
  • Posts: 7792
  • Curiosity
    • View Profile
Re: Friday 16th January 2009
« Reply #2 on: January 16, 2009, 06:50:33 am »
Nice Montage of Markarians Rick!!! :) And yet another informative OOTD. Thanks :D

 I feel I am diagonally parked in a parallel universe  

Hanny

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 17256
  • "Voorwerp kid"
    • View Profile
Re: Friday 16th January 2009
« Reply #3 on: January 16, 2009, 07:04:32 am »
Nice Rick! :)

AlexandredOr

  • Hero Member
  • *****
  • Posts: 25423
    • View Profile
Re: Friday 16th January 2009
« Reply #4 on: January 16, 2009, 07:25:53 am »
Really great ! Thanks !

Baby star opening its eyes on the Universe.

EdV

  • Hero Member
  • *****
  • Posts: 1760
  • ?? ?????? ???????? ????.
    • View Profile
Re: Friday 16th January 2009
« Reply #5 on: January 16, 2009, 11:45:02 am »
Cool! ;D
If you thought that 111 plus 1 was 112, then you don't understand binary.

Rick Nowell

  • Hero Member
  • *****
  • Posts: 1333
  • Bristol, U.K.
    • View Profile
Re: Friday 16th January 2009
« Reply #6 on: January 16, 2009, 11:50:20 am »
Just a note to say that Moderator Alice is going to give a talk to the Bristol Astronomical Society
on the 23rd January (next Friday) EDIT on Galaxy Zoo. All are welcome and it is free to non-members.
The talk is to be held at Bristol Grammar School, which is next to Bristol University, very near the centre.
It would be great if y'all could come along. 7.15pm prompt.
http://www.bristolastrosoc.org.uk/wb/index.php
« Last Edit: January 16, 2009, 03:19:46 pm by Rick Nowell »

Infinity

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 11175
    • View Profile
Re: Friday 16th January 2009
« Reply #7 on: January 16, 2009, 11:55:11 am »
Great, thanks Rick :)

AlexandredOr

  • Hero Member
  • *****
  • Posts: 25423
    • View Profile
Re: Friday 16th January 2009
« Reply #8 on: January 16, 2009, 12:25:12 pm »
Just a note to say that Moderator Alice is going to give a talk to the Bristol Astronomical Society
on the 23rd January (next Friday). All are welcome and it is free to non-members. The talks
are held at Bristol Grammar School, which is next to Bristol University, very near the centre.
It would be great if y'all could come along. 7.15pm prompt.
http://www.bristolastrosoc.org.uk/wb/index.php

Fabulous new ! A talk on what ? What is the subject ?

Baby star opening its eyes on the Universe.

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Re: Friday 16th January 2009
« Reply #9 on: January 16, 2009, 04:55:56 pm »
Condensing this vast subject down to half an hour. :o I am struggling to decide what to leave out!

buck1127

  • Hero Member
  • *****
  • Posts: 2584
    • View Profile
Re: Friday 16th January 2009
« Reply #10 on: January 16, 2009, 05:20:52 pm »
Very nice OOTD, Rick.  Thanks for the great primer on Markarians and throwing in the Pea twist!  Lovely!  :)

Wish that I could come to the talk, Alice, but the cold ocean keeps me grounded here, again! :( :(

"..nothing ruins a peaceful night at home quite like a nuclear firestorm...."  Dave Ross

NGC3314

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 1590
    • View Profile
Re: Friday 16th January 2009
« Reply #11 on: January 16, 2009, 05:26:18 pm »
Alice - You could either talk about 560 galaxies per second or 92 Zooites/second. Okay, maybe your plan to leave things out is the way to go. You could point out that the Zoo is equivalent to about half Bristol's population working on the project.

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Re: Friday 16th January 2009
« Reply #12 on: January 16, 2009, 05:32:31 pm »
 :D :D :D :D :D :D

marinakb

  • Sr. Member
  • ****
  • Posts: 454
  • I'm still a Newbie really......
    • View Profile
Re: Friday 16th January 2009
« Reply #13 on: January 16, 2009, 06:03:51 pm »
Great OOTD, very informative - thank you v much Rick ! :D :D :D :D :D  and, I wish I could come to your talk Alice - let us know how it goes! :D

marke

  • Hero Member
  • *****
  • Posts: 798
    • View Profile
Re: Friday 16th January 2009
« Reply #14 on: January 16, 2009, 06:17:51 pm »
nice OOTD rick.

"'Peas' are an unofficial title for objects that have a very high presence of OIII, or doubly-
ionised Oxygen. OIII has had two of its electrons stripped away because of massive energetic
activity taking place. The term was coined by Hanny here: 
http://www.galaxyzooforum.org/index.php?topic=3638.0   
and was at first, maybe still, humourously applied to objects that appeared green."

yes, i remember that thread well as it was started at about the same time i fist ventured onto galaxy zoo...give peas a chance, eh  :D...seems it worked 8)

as for your lecture, alice, is there any chance that it will/could be 'podcast', for those of us who cant make it? :)
"To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science"

"We can't solve problems by using the same kind of thinking we used when we created them"


Albert Einstein