SHREDS: Sizes of High Redshift galaxies, Energy Distributions, Spectra, x-rays & dust

SHREDS is a project being carried out by Cass Barlow-Hall, Joe Bramwell, Dan Hodder, Michael Merrett, Adam Russ and Oliver Wareing. The aim of the project is to determine the average physical properties of distant galaxies to study how local galaxies may have looked when they were young. This involves investigating approximately 4000 high red shift galaxies and classifying their morphologies and determining other properties, such as their sizes and spectral energy distributions (SED), making use of data from the Hubble Space Telescope (HST). It is from this that the group acronym was derived, giving: Sizes of High Redshift galaxies and their Energy Distributions (Spectral). 

The SHREDS team, from top left to right: Dan Hodder (work package lead), Adam Russ (coordinator), Oliver Wareing (communications lead), Cass Barlow-Hall (theory lead),
Joe Bramwell (administrator) and Michael Merrett (data analysis lead).

Weekly Research Updates:

Week 2

Week 3

Week 4

Week 5

Week 6

Alternatively, read all the update posts in one place.

The first week of datataking involved the group investigating the relationship between the Lyman-alpha redshift and right ascension (RA) and declination (Dec) coordinates for each source. A plot was produced to illustrate this, shown below, which displays the bands of galaxies at different redshifts. 

A plot of Lyman-α redshift (LAE_Redshift) and right ascension (RA) and declination (Dec) coordinates for each galaxy within the data catalogue. Highlighted is the group’s first “result of the week” – a particular source resembling a football player.

The next task undertaken was that of morphology classification, with images of sources being viewed and assigned a type, based on the numerical scheme in which 0 = point-like, 1 = elliptical, 2 = disky and 3 = irregular. Examples of each are displayed in the figure below. This process was carried out by all group members for the 1000 brightest source within the data catalogue, with cut-outs of each source being obtained from COSMOS. The results from each member were then collated and an average type was subsequently determined for each source. This reduced the likelihood of individual classification error and therefore increased the reliability of the results. 

Screenshot 2019-02-02 at 19.55.02
Examples of the morphological classes assigned to the brightest galaxies within the data catalogue.