Search Publications
Discovery of the spectroscopic binary nature of six southern Cepheids
Szabados, L.; Derekas, A.; Kovács, J. +6 more
We present the analysis of photometric and spectroscopic data of six bright Galactic Cepheids: GH Carinae, V419 Centauri, V898 Centauri, AD Puppis, AY Sagittarii and ST Velorum. Based on new radial velocity data (in some cases supplemented with earlier data available in the literature), these Cepheids have been found to be members in spectroscopic…
Revisiting SW J2000.6+3210: a persistent Be X-ray pulsar?
Maitra, Chandreyee; Paul, Biswajit; Pradhan, Pragati +1 more
We present a detailed timing and spectral analysis of the Be X-ray binary SW J2000.6+3210 discovered by the Burst Alert Telescope Galactic plane survey. Two Suzaku observations of the source made at six months interval, reveal pulsations at ∼890 s for both observations with a much weaker pulse fraction in the second one. Pulsations are clearly see…
X-ray emission around the z = 4.1 radio galaxy TN J1338-1942 and the potential role of far-infrared photons in AGN feedback
Smail, Ian; Blundell, Katherine M.
We report the discovery in an 80-ks observation of spatially extended X-ray emission around the high-redshift radio galaxy TN J1388-1942 (z = 4.11) with the Chandra X-ray Observatory. The X-ray emission extends over a ∼30-kpc diameter region and although it is less extended than the GHz-radio lobes, it is roughly aligned with them. We suggest that…
Three active galactic nuclei close to the effective Eddington limit for dusty gas
Fabian, A. C.; Mushotzky, R. F.; Trippe, M. L. +3 more
The effective Eddington limit for dusty gas surrounding active galactic nucleus (AGN) is lower than the canonical Eddington limit for hydrogen gas. Previous results from the Swift/Burst Alert Telescope 9-month catalogue suggested that in the overwhelming majority of local AGN, the dusty absorbing gas is below this effective Eddington limit, implyi…
The three-dimensional geometry and merger history of the massive galaxy cluster MACS J0358.8-2955
Richard, Johan; Ebeling, Harald; Hsu, Li-Yen
We present results of a combined X-ray/optical analysis of the dynamics of the massive cluster MACS J0358.8-2955 (z = 0.428) based on observations with the Chandra X-ray Observatory, the Hubble Space Telescope and the Keck-I telescope on Mauna Kea. MACS J0358.8-2955 is found to be one of the most X-ray luminous clusters known at z > 0.3, featur…
Spectropolarimetric investigation of the photosphere during a solar microflare
Kondrashova, N. N.
The results of the study of the thermodynamical parameters and the magnetic field in the solar photosphere during the solar microflare on 2009 July 4 in the active region NOAA 11024 are presented. The analysis is based on the observations with the French-Italian telescope THEMIS (Heliographic Telescope for the Study of the Magnetism and Instabilit…
Herschel-ATLAS/GAMA: the environmental density of far-infrared bright galaxies at z ≤ 0.5
Ivison, R. J.; Cooray, A.; Ibar, E. +21 more
We compare the environmental and star formation properties of far-infrared detected and non-far-infrared detected galaxies out to z ∼ 0.5. Using optical spectroscopy and photometry from the Galaxy And Mass Assembly (GAMA) and Sloan Digital Sky Survey, with far-infrared observations from the Herschel Astrophysical Terahertz Large Area Survey (ATLAS…
A report on the X-ray properties of the τ Sco-like stars
Massa, D.; Oskinova, L. M.; Ignace, R.
An increasing number of OB stars have been shown to possess magnetic fields. Although the sample remains small, it is surprising that the magnetic and X-ray properties of these stars appear to be far less correlated than expected. This contradicts model predictions, which generally indicate that the X-rays from magnetic stars are harder and more l…
VLT/FORS2 observations of four high-luminosity ULX candidates
Fabian, A. C.; Miniutti, G.; Roberts, T. P. +4 more
We obtained Very Large Telescope/FOcal Reducer and low dispersion Spectrograph spectra of the optical counterparts of four high-luminosity (LX ≥ 1040 erg s-1) Ultraluminous X-ray sources (ULX) candidates from the catalogue of Walton et al. We first determined accurate positions for the X-ray sources from archival C…
Observations of 6-200 µm emission of the Ophiuchus cloud LDN 1688
Juvela, M.; Lemke, D.; Lehtinen, K. +2 more
We examine two positions, ON1 and ON2, within the Ophiuchus cloud LDN 1688 using observations made with the ISO photo-polarimeter (ISOPHOT) instrument aboard the Infrared Space Observatory (ISO) satellite. The data include mid-infrared spectra (∼6-12 µm) and several photometric bands up to 200 µm. The data probe the emission from molec…