The Hickson Compact Groups

Jason Kendall, William Paterson University
kendallj {AT}

All images below come from the Digitized Sky Survey , produced at the Space Telescope Science Institute

Useful links: National Optical Astronomy Observatory Gallery, HubbleSite and Australian Astronomical Observatory Gallery.

Click on an image to get it in a high-resolution format.

The paper we're looking at is the original article where Paul Hickson created a small catalog of groups of galaxies. His goal was to understand the nature of galaxy interactions on the shapes and types of galaxies. He searched by eye the "red" images from the Palomar Sky Survey, so that's what you have on the web page below. At the time he did this, it was not digitized. The search would be much easier today. You'll use the list he create in his paper to answer the questions and find images. You'll also be going to his paper, too. He classified the groups into six categories. "S" if the brightest galaxy in the group is a spiral, and "E" if the brightest galaxy is an elliptical. He then put them into further subcategories. "I" if the brightest one was at least a magnitude brighter than all the others, "II" if it was between a half magnitude and a full magnitude brighter than the second brightest, and "III" if the brightest one was almost the same brightness as the second-brightest galaxy. For example, HCG 1 is an SIII, and HCG 9 is an EI.

You'll need to look at this article to help you with this activity. Hickson Paper.

All of the images below are centered on the group. Click on the image for a full-size version. You'll take the full-size version and look mostly at the center of the image. For nearby groups, it'll take up a big part of the image. For distant groups, they'll look like a tight group of fuzzy patches.










HCG 10

HCG 11

HCG 12

HCG 13

HCG 14

HCG 15

HCG 16

HCG 17

HCG 18

HCG 19

HCG 20

HCG 21

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HCG 96

HCG 97

HCG 98

HCG 99

HCG 100

Acknowledgements for the images used in this exercise

The Digitized Sky Survey was produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.

The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Aeronautics and Space Administration, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. The Oschin Schmidt Telescope is operated by the California Institute of Technology and Palomar Observatory.

The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), the near-IR plates (SERC-I), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt telescope at the AAO.

All images labelled with NOAO are courtesy of National Optical Astronomy Observatory/Association of Universities for Research in Astronomy/National Science Foundation.

All images labelled with AAO copyrighted by the Australian Astronomical Observatory, with photographs by David Malin.