Introduction

In 1982, the Canadian astronomer Paul Hickson, began compiling a catalogue of compact groups of galaxies which he had identified. These groups became known as the Hickson Compact Groups of galaxies, and Hickson published his list of 100 groups in his 'Atlas of Compact Groups of Galaxies'.

The effect of gravity is very important in these compact groups, and results in the galaxies continuously interacting with each other. As such they provide a unique environment for astronomers to study how star formation occurs in this type of dense environment as well as a place to study how galaxies form since some of the tidal tails formed by the galactic encounters have been found to be the birthplace of new galaxies known as tidal dwarfs.

In this project you will make multi-wavelength images of the Hickson Compact Groups (HCG) - this has never been done before in a systematic way, and many of the HCGs have never even had colour images produced of them, so you can help produce one of the first such complete catalogues!

Documents

Below you will find the documents which you will need to read through before starting this project.

Links

Below are links which give more information on compact groups of galaxies and the science projects being carried out on them.

Advanced HCG imaging - Mosaics

A small number of the HCGs will not fit into one image taken with the Faulkes 2m telescopes are they spread out over a larger area than the 4.6 arcmin field of view of the telescopes.

Below you will find documents to help you plan your observing session if you wish to image a HCG which is larger than the field of view of the Faulkes 2m telescopes.

However, you may wish to try out a few easier and smaller groups first before tackling how to plan your mosaic image. For this purpose, the finding charts for 4 HCGs are given below, together with a list of coordinates for the centres of each field which you will need to observe for that HCG.

Instructions on how to piece together your images to make one final image of the HCG are also given below.

Hickson Compact Group Themed Observing Days

On 8th Dec, we held the first of our themed observing days to image the Hickson Compact Groups of galaxies. These compact groups of galaxies are so-called after the Canadian astronomer, Paul Hickson, who began identifying and compiling a catalogue of these objects in the 1980s. His list of 100 groups is published in the ‘Atlas of Compact Groups of Galaxies’, together with black and white images of each group.

The aim of our ‘Hickson Compact Groups’ themed observing days is to produce deep colour images of these groups.

HCG 15, observed on the 8th Dec covers an area of 7.7 arcmin square in the sky, which is larger than the single field of view of the Faulkes Telescope South (4.6 arcmin). So, a mosaic image was observed, which covered the whole of the group, and each participating school were given the central coordinates of 3 of the overlapping areas as shown in the image below.

Weather and the Universe were against us during part of the day - cloud started creeping over the telescope as the day went on, and a gamma ray burst went off in the sky at the start of the observing day so the telescope was taken over to observe this event! But the schools perservered and the data which was obtained can be found below.

Many thanks to the 8 schools who participated in this day:

• Altrincham Grammar School for Boys
• Paulet High School
• Whitchurch High School
• St Bernards High School
• King Edward VI High School for Girls
• Dartford Grammar School
• The Holt School
• Castell Alun High School

Data Files

Tile 1
Tile 2
Tile 3
Tile 4

A link to how to create the full mosaic image of this galaxy group can be found in here.

If you’d like to observe this galaxy group and make your own mosaic image, the tile coordinates are:

Tile Number	RA (h:m:s)	Dec (d:m:s)
1	02 07 45.940	02 09 58.36
2	02 07 32.330	02 09 59.52
3	02 07 45.863	02 06 34.27
4	02 07 32.253	02 06 35.44