arXiv subjects

B. Maughan

Publications and source records attributed to B. Maughan.

21 records · Page 2Linked to original sources

arXiv2009

The spectroscopically confirmed huge cosmic structure at z=0.55

We report on the spectroscopic confirmation of a huge cosmic structure around the CL0016 cluster at z=0.55. We made wide-field imaging observations of the surrounding regions of the cluster and identified more than 30 concentrations of red galaxies near the cluster redshift. The follow-up spectroscopic observations of the most prominent part of the structure confirmed 14 systems close to the cluster redshift, roughly half of which have a positive probability of being bound to the cluster dynamically. We also made an X-ray follow-up, which detected extended X-ray emissions from 70% of the systems in the X-ray surveyed region. The observed structure is among the richest ever observed in the distant Universe. It will be an ideal site for quantifying environmental variations in the galaxy properties and effects of large-scale structure on galaxy evolution.

astro-ph.CO↗

arXiv2009

Application of a Self-Similar Pressure Profile to Sunyaev-Zel'dovich Effect Data from Galaxy Clusters

We investigate the utility of a new, self-similar pressure profile for fitting Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters. Current SZ imaging instruments - such as the Sunyaev-Zel'dovich Array (SZA) - are capable of probing clusters over a large range in physical scale. A model is therefore required that can accurately describe a cluster's pressure profile over a broad range of radii, from the core of the cluster out to a significant fraction of the virial radius. In the analysis presented here, we fit a radial pressure profile derived from simulations and detailed X-ray analysis of relaxed clusters to SZA observations of three clusters with exceptionally high quality X-ray data: A1835, A1914, and CL J1226.9+3332. From the joint analysis of the SZ and X-ray data, we derive physical properties such as gas mass, total mass, gas fraction and the intrinsic, integrated Compton y-parameter. We find that parameters derived from the joint fit to the SZ and X-ray data agree well with a detailed, independent X-ray-only analysis of the same clusters. In particular, we find that, when combined with X-ray imaging data, this new pressure profile yields an independent electron radial temperature profile that is in good agreement with spectroscopic X-ray measurements.

astro-ph↗

arXiv2008

Chandra's View of the Ram Pressure Stripped Galaxy M86

We present results from a mosaic of nine Chandra observations of M86 and the surrounding field. We detect three main diffuse components: the Virgo ICM at ~2.4 keV, the extended halo of M86 at ~1.2 keV, and the cooler central and stripped gas of M86 at ~0.8 keV. The most striking feature is a long tail of emission, which consists of a plume ~ 4' north of M86 and two main extensions emanating from the plume. Based on the morphology and temperature structure of the tail, we conclude that it is formed by ram pressure stripping of M86 as it falls into the Virgo cluster and interacts with the Virgo ICM, in agreement with earlier work. The tail is 150 kpc in projection, and a simple estimate gives a lower limit on the true length of the tail of 380 kpc, making this the longest ram pressure stripped tail presently known. The total gas mass in the plume (7x10^8 M_sun) and tail (1x10^9 M_sun) is about three times that in the core of M86, which supports the scenario where most of the gas was stripped rapidly and recently. The projected position of the plume can be understood if M86 has an aspherical potential, as suggested by optical isophotes. Ram pressure stripping from an aspherical potential can also explain the split "double tails" seen in M86 and in other Virgo cluster galaxies in the field. The large line-of-sight velocity of M86 (1550 km/s with respect to M87), its position relative to the Virgo cluster, and the orientation of the tail tightly constrain its orbital parameters. The data are inconsistent with a radial orbit, and imply inner and outer turning radii of r_i ~ 300 kpc and r_o > 8.8 Mpc, indicating that M86 is, at best, only weakly bound to the Virgo cluster.

astro-ph↗