Search Publications
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 …
The spin of late-type galaxies at redshifts z ≤ 1.2
Hwang, Ho Seong; Park, Changbom; Le Borgne, Damien +2 more
We study the evolution of the galactic spin using data of high-redshift galaxies in the fields of the Great Observatories Origins Deep Survey. Through simple dynamical considerations we estimate the spin for the disc galaxies in our sample and find that its distribution is consistent with that found for nearby galaxies. Defining a dimensionless an…