Search Publications
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…
Unveiling the nature of two unidentified EGRET blazar candidates through spectroscopic observations
Meintjes, P. J.; Nkundabakura, P.
Studies using the Energetic Gamma-Ray Experiment Telescope (EGRET) revealed that blazars [flat-spectrum radio quasars (FSRQs) and BL Lac objects] emit most of their luminosity in the high-energy gamma-ray (E > 100 MeV) range. From the 271 sources observed by EGRET, 131 are still unidentified. A systematic search is conducted to identify possibl…
[O II] emitters at z ∼ 4.6 in the GOODS field: a homogeneous measure of evolving star formation
Banerji, M.; McMahon, R. G.; Venemans, B. P. +2 more
We present the results of a high-redshift, z = 4.6, survey of [O II] λ3727 emission line galaxies in the GOODS-S field. The survey uses deep near-infrared data in the NB2090 (λc = 2.095 µm, Δ λ = 0.02 µm) and Ks (λc = 2.146 µm, Δ λ = 0.324 µm) filters taken with the European Southern Observatory instru…
Analysing the Suzaku spectra of the broad-line Seyfert 1 galaxy CBS 126
Fabian, A. C.; Reis, R. C.; Grupe, D. +2 more
We analysed new simultaneous Suzaku and Swift data of the broad-line Seyfert 1 (BLS1) galaxy CBS 126. A clear Fe emission line and a strong soft excess are present in the source spectra. We fit the spectra with a relativistic reflection model and find that the model tends to fit the data with a high iron abundance possibly due to the large soft ex…
The search for high-mass X-ray binaries in the Phoenix dwarf galaxy
Haberl, F.; Bartlett, E. S.; Coe, M. J. +2 more
We report on the first X-ray images of the Phoenix dwarf galaxy, taken with XMM-Newton in 2009 July. This Local Group dwarf galaxy shares similarities with the Small Magellanic Cloud (SMC) including a burst of star formation ∼50 Myr ago. The SMC has an abundance of high-mass X-ray binaries (HMXBs) and so we have investigated the possibility of an …
Accurate positions for the ultraluminous X-ray sources NGC 7319-X4 and NGC 5474-X1 and limiting magnitudes for their optical counterparts
Torres, M. A. P.; Heida, M.; Jonker, P. G. +1 more
In this paper, we report accurate Chandra positions for two ultraluminous X-ray sources (ULXs): NGC 7319-X4 at Right Ascension (RA) = 339?029 17(2), Declination (Dec.) = 33?974 76(2) and NGC 5474-X1 at RA = 211?248 59(3), Dec. = 53?635 84(3). We perform bore-sight corrections on the Chandra X-ray satellite observations of these sources to get thes…
Tracing colliding winds in the ultraviolet line orbital variability of gamma-ray binaries
McSwain, M. Virginia; Dubus, Guillaume; Szostek, Anna
Gamma-ray binaries emit most of their radiated power beyond ∼10 MeV. The non-thermal emission is thought to arise from the interaction of the relativistic wind of a rotation-powered pulsar with the stellar wind of its massive (O or Be) companion star. A powerful pulsar creates an extended cavity, filled with relativistic electrons, in the radiativ…
XMM-Newton confirmation of a new intermediate polar: XMMU J185330.7-012815
Hui, C. Y.; Sriram, K.; Choi, C. -S.
We report on the results of a detailed spectro-imaging and temporal analysis of an archival XMM-Newton observation of a new intermediate polar XMMU J185330.7-012815. Its X-ray spectrum can be well described by a multitemperature thermal plasma model with the K lines of heavy elements clearly detected. Possible counterparts of XMMU J185330.7-012815…
A multifrequency approach of the cosmological parameter estimation in the presence of extragalactic point sources
Aghanim, N.; Douspis, M.; Finelli, F. +4 more
We present a multifrequency approach which optimizes the constraints on cosmological parameters with respect to extragalactic point source and secondary anisotropy contamination on small scales. We model with a minimal number of parameters the expected dominant contaminations in intensity, such as unresolved point sources and the thermal Sunyaev-Z…
Star formation history and environment of the dwarf galaxy UGCA 92
Makarova, Lidia; Makarov, Dmitry; Savchenko, Sergey
We present a quantitative star formation history of the nearby dwarf galaxy UGCA 92. This irregular dwarf is situated in the vicinity of the Local Group of galaxies in a zone of strong Galactic extinction (IC 342 group of galaxies). The galaxy was resolved into stars, including the old red giant branch, with HST/ACS. We constructed a model of the …