Search Publications
ATCA observations of the MACS-Planck Radio Halo Cluster Project. II. Radio observations of an intermediate redshift cluster sample
Brunetti, G.; Aghanim, N.; Arnaud, M. +16 more
Aim. A fraction of galaxy clusters host diffuse radio sources whose origins are investigated through multi-wavelength studies of cluster samples. We investigate the presence of diffuse radio emission in a sample of seven galaxy clusters in the largely unexplored intermediate redshift range (0.3 < z < 0.44).
Methods: In search of diffuse…
Warm CO in evolved stars from the THROES catalogue. I. Herschel-PACS spectroscopy of O-rich envelopes
García-Lario, P.; Sánchez Contreras, C.; da Silva Santos, J. M. +1 more
In this work (Paper I), we analyse Herschel-PACS spectroscopy for a subsample of 23 O-rich and 3 S-type evolved stars, in different evolutionary stages from the asymptotic giant branch (AGB) to the planetary nebula (PN) phase, from the THROES catalogue. (C-rich targets are separately studied in Paper II). The broad spectral range covered by PACS (…
Detection of low-metallicity warm plasma in a galaxy overdensity environment at z ∼ 0.2
Savage, Blair D.; Wakker, Bart P.; Narayanan, Anand +3 more
We present results from the analysis of a multiphase O VI-broad Ly α (BLA) absorber at z = 0.19236 in the HubbleSpaceTelescope/Cosmic Origins Spectrograph spectrum of PG 1121 + 422. The low and intermediate ionization metal lines in this absorber have a single narrow component, whereas the Ly α has a possible broad component with b({H {I}}) ∼ 71 k…
Does the solar granulation change with the activity cycle?
Ichimoto, K.; Utz, D.; Hanslmeier, A. +1 more
Context. Knowledge of the variation of the solar granulation properties (contrast and scale) with the 11-yr activity cycle is useful for a better understanding of the interaction between magnetic field and convection at global or local scales. A varying granulation may also contribute to irradiance variations and affect the p-mode damping rates an…
On the high energy cut-off of accreting sources: Is general relativity relevant?
Tamborra, Francesco; Papadakis, Iossif; Dovčiak, Michal +1 more
The hard X-ray emission observed in accreting compact sources is believed to be produced by inverse Compton scattering of soft photons arising from the accretion disc by energetic electrons thermally distributed above the disc, the so-called X-ray corona. Many independent observations suggest that such coronae should be compact and located very cl…
Searching for Binary Systems Among Nearby Dwarfs Based on Pulkovo Observations and SDSS Data
Izmailov, I. S.; Khovrichev, M. Yu.; Apetyan, A. A. +9 more
Our goal is to find previously unknown binary systems among low-mass dwarfs in the solar neighborhood and to test the search technique. The basic ideas are to reveal the images of stars with significant ellipticities and/or asymmetries compared to the background stars on CCD frames and to subsequently determine the spatial parameters of the binary…
Variable blurred reflection in the narrow-line Seyfert 1 galaxy Mrk 493
Fabian, A. C.; Gallo, L. C.; Wilkins, D. R. +1 more
We examine a 200 ks XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 493. The active galaxy was half as bright as in a previous 2003 snapshot observation and the current lower flux enables a study of the putative reflection component in detail. We determine the characteristics of the 2015 X-ray continuum by first analysing the short-…
X-ray Luminosity Function of Quasars at 3 < z < 5 from XMM-Newton Serendipitous Survey Data
Sazonov, S. Yu.; Khorunzhev, G. A.; Burenin, R. A.
The X-ray luminosity function of distant (3 < z < 5.1) type 1 quasars has been measured. A sample of distant high-luminosity (1045 erg s-1 ≤ L X,2-10 < 7.5×1045 erg s-1 in the 2-10 keV energy band) quasars from the catalog by Khorunzhev et al. (2016) compiled from the data of the 3XMM…
UV astronomy throughout the ages: a historical perspective
Linsky, Jeffrey L.
Astronomers have long recognized the critical need for ultraviolet imaging, photometry and spectroscopy of stars, planets, and galaxies, but this need could not be satisfied without access to space and the development of efficient instrumentation. When UV measurements became feasible, first with rockets and then with satellites, major discoveries …
The ultrafast outflow of WKK 4438: Suzaku and NuSTAR X-ray spectral analysis
Fabian, Andrew C.; Walton, Dominic J.; Jiang, Jiachen +1 more
Previous X-ray spectral analysis has revealed an increasing number of active galactic nuclei (AGNs) with high accretion rates where an outflow with a mildly relativistic velocity originates from the inner accretion disc. Here we report the detection of a new ultrafast outflow (UFO) with a velocity of v_out=0.319^{+0.005}_{-0.008}c in addition to a…