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A 20 GHz bright sample for δ > +72° - I. Catalogue
Prandoni, I.; Ricci, R.; López-Caniego, M. +9 more
During 2010-11, the Medicina 32-m dish hosted the seven-feed 18-26.5 GHz receiver built for the Sardinia Radio Telescope, with the goal to perform its commissioning. This opportunity was exploited to carry out a pilot survey at 20 GHz over the area for δ > +72°.3. This paper describes all the phases of the observations, as they were performed u…
Optical polarization of quasars and the Balmer edge feature revealed by ultraviolet and polarized visible to near-infrared emissions
Hu, Renyu; Zhang, Shuang-Nan
Polarized emission from a quasar is produced by wavelength-independent electron scattering that surrounds its accretion disc. Thus, contamination from the host galaxy is avoided and the intrinsic emission spectrum of its accretion disc is revealed. Ultraviolet (UV) emission from a quasar is normally free of contamination from its host galaxy. Ther…
Erratum: Herschel/SPIRE observations of the TWA brown dwarf disc 2MASSW J1207334-393254★
Lodato, G.; Riaz, B.; Stamatellos, D. +1 more
We have revised our analysis of the SPIRE observations of 2MASSW J1207334-393254 (2M1207). Recent PACS observations show a bright source located ∼25 arcsec east of 2M1207. There are issues in terms of the detection/non-detection of the bright source when comparing the Spitzer, WISE and PACS observations. The object's detection/non-detection is app…
Discovery of the spectroscopic binary nature of the Cepheids X Puppis and XX Sagittarii
Szabados, László; Kiss, Csaba; Derekas, Aliz +1 more
We present the analysis of photometric and spectroscopic data of two bright Galactic Cepheids, X Puppis and XX Sagittarii. Based on the available data in the literature as well as our own observations spanning 75 years, we conclude that both Cepheids belong to spectroscopic binary systems. However, the data are not sufficient to determine the orbi…
An X-ray/optical study of the geometry and dynamics of MACS J0140.0-0555, a massive post-collision cluster merger
Richard, Johan; Ho, I. -Ting; Ebeling, Harald
We investigate the physical properties, geometry and dynamics of the massive cluster merger MACS J0140.0-0555 (z = 0.451) using X-ray and optical diagnostics. Featuring two galaxy overdensities separated by about 250 kpc in projection on the sky, and a single peak in the X-ray surface brightness distribution located between them, MACS J0140.0-0555…
Misleading variations in estimated rotational frequency splittings of solar p modes: consequences for helioseismology and asteroseismology
Chaplin, William J.; García, Rafael A.; Mathur, Savita +4 more
The aim of this paper is to investigate whether there are any 11-yr or quasi-biennial solar-cycle-related variations in solar rotational splitting frequencies of low-degree solar p modes. Although no 11-yr signals were observed, variations on a shorter time-scale (∼2 yr) were apparent. We show that the variations arose from complications/artefacts…
The first optical light from the supernova remnant G182.4+4.3 located in the Galactic anticentre region
Sezer, A.; Gök, F.; Aktekin, E.
We report the discovery of optical filamentary and diffuse emission from G182.4+4.3 using the 1.5-m Russian-Turkish telescope. We present the optical CCD images obtained with the Hα filter, revealing the presence of mainly filamentary structure to the north-west and filamentary and diffuse structure in the centre, south and north regions of the re…
Ultraviolet variability of the helium-peculiar star a Centauri
Sokolov, N. A.
The spectrophotometric variability of the classical magnetic chemically peculiar star a Cen in the ultraviolet spectral region from 1150 to 3100 Å is investigated. This study is based on archival International Ultraviolet Explorer data obtained at various phases of the rotational cycle. The light variations in wavelengths shorter than λ1616 Å are …
On the nature of high X-ray luminosities in Sloan Digital Sky Survey galaxies
Alexander, D. M.; Wardlow, J. L.; Watson, M. G. +5 more
Surveys have revealed a class of object displaying both high X-ray luminosities (LX > 1042 erg s-1) and a lack of a discernible active galactic nucleus (AGN) in the optical band. If these sources are powered by star formation activity alone, they would be the most extreme X-ray luminosity star-forming galaxies k…
Modelling the multiband spectrum of IGR J17177-3656
Ma, Renyi
The correlation between radio and X-ray luminosity in the hard state of black hole X-ray binaries is important for unveiling the relation between the accretion flow and the jets. In this Letter, we have modelled the quasi-simultaneous multiband observations of a recently discovered transient X-ray source, IGR J17177-3656. It is found that the sour…