The Cosmic Web and galaxy evolution around the most luminous X-ray cluster: RX J1347.5−1145

Abstract

In this paper we study large‐scale structures and their galaxy content around the most X‐ray luminous cluster known, RX J1347.5−1145 at z= 0.45. We make use of u*g′r′i′z′ Canada–France–Hawaii Telescope (CFHT) MegaCam photometry together with VIsible MultiObject Spectrograph (VIMOS) Very Large Telescope (VLT) spectroscopy to identify structures around RX J1347 on a scale of ∼20 × 20 Mpc2. We construct maps of the galaxy distribution and the fraction of blue galaxies. We study the photometric galaxy properties as a function of the environment traced by the galaxy density. We identify group candidates based on galaxy overdensities and study their galaxy content. We also use available Galaxy Evolution Explorer (GALEX) near‐ultraviolet imaging to identify strong unobscured star‐forming galaxies. We find that the large‐scale structure around RX J1347 extends in the north‐east–south‐west direction for at least 20 Mpc, over a region in which most of the group candidates are located, some of which show X‐ray emission in archival XMM–Newton observations. As in other studies, we find that the fraction of blue galaxies (Fblue) is a function of galaxy number density, but the bulk of the trend is due to galaxies belonging to massive systems. The fraction of ultraviolet‐ (UV‐) bright galaxies is also a function of environment, but their relative number compared with the blue population seems to be constant regardless of the environment. These UV emitters also have similar properties at all galaxy densities, indicating that the transition between galaxy types occurs over short time‐scales. Candidate galaxy groups show a large variation in their galaxy content and Fblue in those groups displays little dependence on galaxy number density. This may indicate possible differences in their evolutionary status, or suggest that the processes acting in groups are different from those in clusters. The large‐scale structure around rich clusters provides a dynamic environment for galaxy evolution. In the case of RX J1347, the transformation may start within infalling groups and finish with the removal of the cold gas once galaxies are accreted into massive systems.

The XXL Survey

“…On the other hand, XLSSC-e tends to differ from other known superclusters at those redshifts: instead of having a massive central cluster with infalling filaments and smaller structures, it has almost two equal-sized objects, making it qualitatively different from the network around an already formed massive cluster such as RXJ 1347 (Verdugo et al 2012). While it is very difficult to infer any dynamical information from such a small number of redshifts, if we put together the relatively small crossing time, the common X-ray emission of three members, and the measured gas fraction and mass, we can speculate that we are observing an un-relaxed structure with an ongoing merging between at least three of the member clusters.…”

“…If we compare our supercluster with the low redshift sample of Chon et al (2013) we find that its X-ray luminosity (1.7 × 10 44 erg s −1 in the 0.1−2.4 keV band relevant for the comparison) is close to the median of that sample; with respect to other supercluster at z ≥ 0.4 (see Verdugo et al 2012;Geach et al 2011;Schirmer et al 2011;Lubin et al 2009;Kartaltepe et al 2008;Tanaka et al 2007) our object has a total mass (M 200 obtained using a conversion of r 200 /r 500 = 1.52, Piffaretti et al 2011) of 2.3 × 10 15 M , again in the middle of the range of the few known objects (see e.g. Table 1 in Schirmer et al 2011).…”

First observation of the thermal Sunyaev-Zel’dovich effect with kinetic inductance detectors

“…Allen et al 2002). It was discovered in the ROSAT X-ray all-sky survey (Voges et al 1999) and has been the object of many studies in X-ray (Schindler et al 1995(Schindler et al , 1997Allen et al 2002;Gitti & Schindler 2004, 2005Gitti et al 2007b,a;Ota et al 2008), optical (Cohen & Kneib 2002;Verdugo et al 2012), infrared (Zemcov et al 2007), tSZ (Pointecouteau et al 1999;Komatsu et al 1999Komatsu et al , 2001Pointecouteau et al 2001;Kitayama et al 2004;Mason et al 2010;Korngut et al 2011;Zemcov et al 2012;Plagge et al 2013), and multiwavelength analysis (Bradač et al 2008;Miranda et al 2008;Johnson et al 2012). From ROSAT X-ray observations, this cluster was thought to be a dynamically old relaxed cool-core cluster with an extremely strong cooling flow, due to its very spherical morphology and peaked X-ray profile (ROSAT; Schindler et al 1995Schindler et al , 1997.…”

An excess of dusty starbursts related to the Spiderweb galaxy

“…The following hypothesis could explain these findings: both populations are massive but those in the centre have lost their gas; those that are still infalling have gas and are possibly being disturbed which makes them more active (see e.g. Verdugo et al 2012, for details on this kind of scenario at low redshift). The HAE and SMG centres seem to be inconsistent, see Fig.…”