Data Products


The Complete Local Volume Groups Sample - I. Sample Selection and X-ray Properties of the High-Richness Subsample (O'Sullivan et al. 2017) describes the sample selection process and results from the X-ray analysis of the 26-group high-richness subsample. The paper discusses the fraction of groups with group and galaxy-scale X-ray halos, cool cores, evidence of mergers, and central radio jet sources, and the relationships between these properties. It also discusses the lack of high-entropy groups in the sample, the tendency for the lowest mass groups to have central temperature peaks, and the lessons that can be drawn from CLoGS for future X-ray group surveys.

Cold gas in group-dominant elliptical galaxies (O'Sullivan et al. 2015) uses CLoGS as a basis to examine the molecular gas content of group-central early-type galaxies. Using a subset of the CLoGS groups observed by the IRAM 30m telescope, the paper finds a relatively high detection rate for CO, but a short depletion time (despite low star formation rates) indicating that group-central galaxies must replenish their molecular gas reservoirs on timescales ~100 Myr.

Conference Talks and Posters

Initial results from CLoGS are presented in two conference proceedings papers, O'Sullivan et al. (2014) and Kolokythas et al. (2014), from The Metrewavelength Sky conference in Pune, India, December 2013.

Slides from the CLoGS talks given by Ewan O'Sullivan and Konstantinos Kolokythas at The Metrewavelength Sky (left). CLoGS posters presented at the 2013 AAS HEAD meeting in Monterey, by Jan Vrtilek (centre) and at the 2013 UK National Astronomy Meeting in St. Andrews, by Konstantinos Kolokythas (right). Click to download PDF versions.
CLoGS summary and first results: talk from the Metrewavelength Sky conference, December 2013 CLoGS poster from the 2013 AAS High Energy Astrophysics Division meeting CLoGS poster from the 2013 UK National Astronomy Meeting
Radio properties of CLoGS groups: talk from the Metrewavelength Sky conference, December 2013

Example Images

Some example images from our first XMM-Newton dataset, showing LGG 402, are shown below.

X-ray/optical composite image of LGG 402, aka the Draco Triplet.
Smoothed XMM-Newton X-ray emission in blue, overlaid on an SDSS u,g,r,i composite optical image. We are able to trace the physical properties of the intra-group gas (temperature, density, entropy, etc.) out to around 85 kpc.
SDSS g-band optical image of NGC 5985, with GMRT 610 MHz contours overlaid. SDSS g-band optical image of NGC 5982, with GMRT 610 MHz contours overlaid. SDSS g-band optical image of NGC 5981, with GMRT 610 MHz contours overlaid.
GMRT 610 MHz radio contours (c/o Konstantinos Kolokythas) overlaid on optical images of the three main galaxies. Contours start at 270 microJanskys (3 x r.m.s.) and increase by factors of 2. The Seyfert nucleus of NGC 5985 (left) is clearly detected in X-ray and radio, and the AGN in NGC 5982 (centre) also shows up as a radio source. The diffuse radio emission is detected from the disks of NGC 5985 (left) and NGC 5981 (right) is a product of the ongoing star formation in these galaxies.