اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدImaging and spectroscopy of arcs around the most luminous X-ray cluster RX J1347.5-1145
155
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The cluster RX J1347.5-1145, the most luminous cluster in the X-ray wavelengths, was imaged with the newly installed Space Telescope Imaging Spectrograph (STIS) on-board HST. Its relatively high redshift (0.451) and luminosity indicate that this is one of the most massive of all known clusters. The STIS images unambiguously show several arcs in the cluster. The largest two arcs (> 5 arcsec in length) are symmetrically situated on opposite sides of the cluster, at a distance of ~ 35 arcsec from the central galaxy. The STIS images also show approximately 100 faint galaxies within the radius of the arcs whose combined luminosity is ~ 4 x 10^11 Lsun. We also present ground-based spectroscopic observations of the northern arc which show one clear emission line at 6730 A, which is consistent with an identification as [OII] 3727 A, implying a redshift of 0.81 for this arc. The southern arc shows a faint continuum but no emission features. The surface mass within the radius of the arcs (240 kpc), as derived from the gravitational lensing, is 6.3 x 10^14 Msun. The resultant mass-to-light ratio of ~1200 is higher than what is seen in many clusters but smaller than the value recently derived for some `dark X-ray clusters (Hattori et al. 1997). The total surface mass derived from the X-ray flux within the radius of the arcs is ~2.1 - 6.8 x 10^14 Msun, which implies that the ratio of the gravitational to the X-ray mass is ~1 to 3. The surface GAS mass within this radius is ~3.5 x 10^13 Msun, which implies that at least 6% of the total mass within this region is baryonic.
قيم البحث
اقرأ أيضاً
The galaxy cluster RX J1347-1145 is one of the most X-ray luminous and most massive clusters known. Its extreme mass makes it a prime target for studying issues addressing cluster formation and cosmology. In this paper we present new high-resolution
HST/ACS and Chandra X-ray data. The high resolution and sensitivity of ACS enabled us to detect and quantify several new multiply imaged sources, we now use a total of eight for the strong lensing analysis. Combining this information with shape measurements of weak lensing sources in the central regions of the cluster, we derive a high-resolution, absolutely-calibrated mass map. This map provides the best available quantification of the total mass of the central part of the cluster to date. We compare the reconstructed mass with that inferred from the new Chandra X-ray data, and conclude that both mass estimates agree extremely well in the observed region, namely within 400 / h_70 kpc of the cluster center. In addition we study the major baryonic components (gas and stars) and hence derive the dark matter distribution in the center of the cluster. We find that the dark matter and baryons are both centered on the BCG within the uncertainties (alignment is better than <10 kpc). We measure the corresponding 1-D profiles and find that dark matter distribution is consistent with both NFW and cored profiles, indicating that a more extended radial analysis is needed to pinpoint the concentration parameter, and hence the inner slope of the dark matter profile.
We report on new VLA radio observations of the distant cluster RX J1347.5-1145, which is the most luminous in X-rays. We aim at investigating the possible presence of diffuse and extended radio emission in this very peculiar system which shows both a
massive cooling flow and merging signatures. New low resolution (~18 arcsec) VLA radio observations of this cluster are combined with higher resolution (~2 arcsec) data available in the VLA archive. We discover the presence of a diffuse and extended (~500 kpc) radio source centered on the cluster, unrelated to the radio emission of the central AGN. The properties of the radio source, in particular a) its occurrence at the center of a massive cooling flow cluster, b) its total size comparable to that of the cooling region, c) its agreement with the observational trend between radio luminosity and cooling flow power, indicate that RX J1347.5-1145 hosts a radio mini-halo. We suggest that the radio emission of this mini-halo, which is the most distant object of its class discovered up to now, is due to electron re-acceleration triggered by the central cooling flow. However, we also note that the morphology of the diffuse radio emission shows an elongation coincident with the position of a hot subclump detected in X-rays, thus suggesting that additional energy for the electron re-acceleration might be provided by the submerger event.
We have shown that the cluster-mass reconstruction method which combines strong and weak gravitational lensing data, developed in the first paper in the series, successfully reconstructs the mass distribution of a simulated cluster. In this paper we
apply the method to the ground-based high-quality multi-colour data of RX J1347.5-1145, the most X-ray luminous cluster to date. A new analysis of the cluster core on very deep, multi-colour data analysis of VLT/FORS data reveals many more arc candidates than previously known for this cluster. The combined strong and weak lensing reconstruction confirms that the cluster is indeed very massive. If the redshift and identification of the multiple-image system as well as the redshift estimates of the source galaxies used for weak lensing are correct, we determine the enclosed cluster mass in a cylinder to M(<360 h^-1 kpc)= (1.2 +/- 0.3) 10^15 Msun. In addition the reconstructed mass distribution follows the distribution found with independent methods (X-ray measurements, SZ). With higher resolution (e.g. HST imaging data) more reliable multiple imaging information can be obtained and the reconstruction can be improved to accuracies greater than what is currently possible with weak and strong lensing techniques.
In this paper we study the 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 ugriz CFHT MEGACAM photometry and VIMOS VLT spectroscopy to identify structures around
the RXJ1347 on a scale of 20x20 Mpc2. We construct maps of the galaxy distribution and the fraction of blue galaxies. We study the photometric galaxy properties as a function of environment, traced by the galaxy density. We identify group candidates based on galaxy overdensities and study their galaxy content. We also use available GALEX NUV imaging to identify strong unobscured star forming galaxies. We find that the large scale structure around RXJ1347 extends in the NE-SW direction for at least 20 Mpc, in which most of the group candidates are located. As 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 the UV-bright galaxies is also function of environment, but their relative numbers compared to 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 in short time-scales. Candidate galaxy groups show a large variation in their galaxy content and Fblue in those groups display little dependence with galaxy density. This may indicate possible differences in their evolutionary status or the processes that are acting in groups are different than in clusters. The large scale structure around rich clusters are dynamic places for galaxy evolution. In the case of RXJ1347 the transformation may start within infalling groups to finish with the removal of the cold gas once galaxies are accreted in massive systems. (ABRIDGED)
We present a revised strong lensing mass reconstruction of the galaxy cluster RX J1347.5-1145. The X-ray luminous cluster at redshift z=0.451 has already been studied intensively in the past. Based on information of two such previous (strong-)lensing
studies by Halkola et al. (2008) and Bradac et al. (2008), as well as by incorporating newly available data from the Cluster Lensing And Supernovae survey with Hubble (CLASH, Postman et al. 2012), we identified four systems of multiply lensed images (anew) in the redshift range 1.75 <= z <= 4.19. One multiple image system consists of in total eight multiply lensed images of the same source. The analysis based on a parametric mass model derived with the software glafic (Oguri 2010) suggests that the high image multiplicity is due to the source (z_phot = 4.19) being located on a so-called swallowtail caustic. In addition to the parametric mass model, we also employed a non-parametric approach using the software PixeLens (Saha and Williams 1997, 2004) in order to reconstruct the projected mass of the cluster using the same strong lensing data input. Both reconstructed mass models agree in revealing several mass components and a highly elliptic shape of the mass distribution. Furthermore, the projected mass inside, for example, a radius R ~35 arcsec ~200 kpc of the cluster for a source at redshift z=1.75 obtained with PixeLens exceeds the glafic estimate within the same radius by about 13 per cent. The difference could be related to the fundamental degeneracy involved when constraining dark matter substructures with gravitationally lensed arcs.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
