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Probing dark energy via galaxy cluster outskirts
Sun, Ming; Morandi, Andrea
We present a Bayesian approach to combine Planck data and the X-ray physical properties of the intracluster medium in the virialization region of a sample of 320 galaxy clusters (0.056 < z < 1.24, kT ≳ 3 keV) observed with Chandra. We exploited the high level of similarity of the emission measure in the cluster outskirts as cosmology proxy. …
Evidence for a Magnetic Flux Rope in Observations of a Solar Prominence-Cavity System
Reeves, Katharine K.; Su, Yingna; Jibben, Patricia R.
Testing distance duality with CMB anisotropies
Räsänen, Syksy; Väliviita, Jussi; Kosonen, Ville
We constrain deviations of the form T propto (1+z)1+epsilon from the standard redshift-temperature relation, corresponding to modifying distance duality as DL = (1+z)2(1+epsilon) DA. We consider a consistent model, in which both the background and perturbation equations are changed. For this purpose, we …
A deep Chandra observation of the interacting star-forming galaxy Arp 299
Zezas, A.; Ballo, L.; Della Ceca, R. +1 more
We present results from a 90 ks Chandra ACIS-S observation of the X-ray luminous interacting galaxy system Arp 299 (NGC 3690/IC 694). We detect 25 discrete X-ray sources with luminosities above ∼4.0 × 1038 erg s-1 covering the entire Ultra Luminous X-ray source (ULX) regime. Based on the hard X-ray spectra of the non-nuclear …
The supermassive black hole and double nucleus of the core elliptical NGC 5419
Bender, Ralf; Thomas, Jens; Fabricius, Maximilian H. +5 more
We obtained adaptive-optics assisted SINFONI observations of the central regions of the giant elliptical galaxy NGC 5419 with a spatial resolution of 0.2 arcsec (≈55 pc). NGC 5419 has a large depleted stellar core with a radius of 1.58 arcsec (430 pc). HST and SINFONI images show a point source located at the galaxy's photocentre, which is likely …
A Hot Gaseous Galaxy Halo Candidate with Mg X Absorption
Bregman, Joel N.; Qu, Zhijie
The hot gas in galaxy halos may account for a significant fraction of missing baryons in galaxies, and some of these gases can be traced by high ionization absorption systems in QSO UV spectra. Using high S/N Hubble Space Telescope/Cosmic Origins Spectrograph spectra, we discovered a high ionization state system at z = 1.1912 in the sightline towa…
Discovery of X-Ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku
Safi-Harb, Samar; Petre, Robert; Terada, Yukikatsu +6 more
We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spec…
X-rays beware: the deepest Chandra catalogue of point sources in M31
Barmby, P.; Vulic, N.; Gallagher, S. C.
This study represents the most sensitive Chandra X-ray point source catalogue of M31. Using 133 publicly available Chandra ACIS-I/S observations totalling ∼1 Ms, we detected 795 X-ray sources in the bulge, north-east, and south-west fields of M31, covering an area of ≈0.6 deg2, to a limiting unabsorbed 0.5-8.0 keV luminosity of ∼10…
The distribution of dark and luminous matter in the unique galaxy cluster merger Abell 2146
McNamara, Brian R.; Fabian, Andrew C.; Santana, Rebecca +9 more
Abell 2146 (z = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the Chandra X-ray Observatory, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the tota…
Level of helium enhancement among M3's horizontal branch stars
Contreras Ramos, R.; Catelan, M.; Alonso-García, J. +2 more
Context. The color and luminosity distribution of horizontal branch (HB) stars in globular clusters (GCs) are sensitive probes of the original helium abundances of those clusters. In this sense, recently the distributions of HB stars in GC color-magnitude diagrams (CMDs) have been extensively used as indicators of possible variations in the helium…