Tag Archive | OOTW

Galaxies spiralling out of control

Today’s OOTW features Alice’s OOTD, posted on the 29th of July.


AHZ40004wr from Hubble Zoo

This is AHZ40004wr, a galaxy residing in the constellation Taurus around 3 billion light years away. It’s a wonderful spiral galaxy, and following its spiral arms is a large dust lane, a place full of young stars and stars that are only just being formed.

AHZ40004wr by Swengineer

AHZ40004wr by Swengineer

Zooite Swengineer gave us a wider view of AHZ40004wr and the surrounding galaxies by working with the FITS images and revealed the mess of galaxies above. The main spiral galaxy in the background is 2MASS J03324999-2734330, an X-ray source according to SIMBAD, and it is also around 3 billion light years away.

You can view more images of these galaxies here and here, and to work with the FITS files I recommend DS9 or Aladin, which I used to find the other galaxies details.

And to highlight a request from Alice’s OOTD, Alice would very much like to know if anyone could write any FITS and image editing tutorials on the galaxy zoo forum.

The Sunflower of Canes Venatici

This galaxy is featured in LizPeter’s OOTD for 24th of July 2010.


M63 from the SDSS

This is Messier 63, though I much prefer its other name, the sunflower galaxy. It’s a wonderful dusty spiral galaxy lying 22.9 million light years away from Earth in the constellation Canes Venatici. It’s one of 7 galaxies bound gravitationally together in the M51 group, and according to Wikipedia, it is one of the first objects to be seen to have spiral arms. This was pointed out in 1845 by William Parsons in a time when these objects were thought to be ‘spiral nebulae’ in our own galaxy, and not galaxies themselves. SIMBAD also claims that there is a cluster of stars lying in the foreground of the galaxy.

There are some brilliant Hubble Legacy images and spectra here, and some more from assorted observatories here!

Markarian and the Blob

Today’s OOTW features an OOTD written by Alice on the 15th of July.

117 million light years away there lies a Markarian galaxy and a very interesting companion. As Alice says in her OOTD, these Markarians are galaxies that emit strongly in ultraviolet and visible light, and are often a host to AGN.

During the observation run at Kitt Peak the Galaxy Zoo team had some spare telescope time going after observing a list of Voorwerpjes, so Bill Keel asked Zooites on the forum to provide objects to get a spectrum for:

MRK 490

MRK 490 and its blue companion.

The bright blue blobby companion just above the Markarian galaxy MRK 490 centred in the picture above was one such object that was observed. The companion is brimming with new stars as shown by the huge emission line (amongst others) of OIII at around 5000 angstroms in the spectrum below, the object is very close to the galaxy below it going by their redshift, so it is suspected to be interacting with it!

Spectrum for MKN 490's companion

Spectrum for MKN 490's companion; click for larger image.

From Blob to Collisional Ring

This week’s OOTW features this object (below) from Tsering’s OotD posted on the 26th of June.

AHZ30000yv SDSS Version

AHZ30000yv from Sloan's view

As Tsering showed, this seemingly uninteresting blob on the SDSS turns into this in Hubble Zoo:


AHZ30000yv from Hubble's view

This is AHZ30000yv, a wonderful collisional ring galaxy! I love seeing the huge differences between the SDSS and Hubble images, the reason why Hubble can see more is because it’s out of the way of the Earth’s atmosphere, so even though Hubble is actually smaller than the the Sloan telescope (Hubble’s mirror is 2.4 meters and the Sloan telescope’s mirror is 2.5) it can see further, taking us visually back to when the universe was around half its current age and making me very happy indeed!

This ring galaxy has a Z (redshift) of 1.432, so we’re seeing it as it was 9.15 billion years ago, just under 5 billion years after the big bang! So how did this galaxy end up as a collisional ring? The ring formed after another smaller galaxy punched through the centre of the galaxy, creating masses of hot young blue stars in the process through all the gravitational disruption.

And I have to quote this lovely post by Budgieye from the comments on Tsering’s OotD 😀 :

It is fun looking at the difference.
There must be lots of UV light coming from it, otherwise nothing would be visible at all on SDSS.  At that distance, the ordinary blue light from the stars would be redshifted off the limits of the SDSS detector for far red light.
A nice addition to
Colours of Galaxies in SDSS : Redshift chart

Binary Star System in Cetus

*80 Cet

*80 Cet

80 Cet, a star posted by Zooite and moderator Infinity on Sunday 20th June 2010 for Father’s Day, is in fact locked gravitationally to another star, both orbiting around each other on their common centre of mass. Interestingly, around one in three stars in our galaxy are found in binary or multiple star systems.

I couldn’t glean much information on the stars but with the help of SIMBAD and Peter Clark (@lightbulb500) from the Young Astronomers website, we both agreed that it’s likely to be a Red Giant paired with a White Dwarf star -please point out if we have the classification wrong!

Sources: Wikipedia and Binary Stars Blitzed.