Search Publications
Herschel far-IR counterparts of SDSS galaxies: analysis of commonly used star formation rate estimates
Berta, S.; Magnelli, B.; Lutz, D. +13 more
We study a hundred of galaxies from the spectroscopic Sloan Digital Sky Survey (SDSS) with individual detections in the far-infrared Herschel Photodetector Array Camera and Spectrometer bands (100 or 160 µm) and in the GALEX far-ultraviolet band up to z ∼ 0.4 in the COSMOS and Lockman Hole fields. The galaxies are divided into four spectral …
The quiescent state of the accreting X-ray pulsar SAX J2103.5+4545
Zezas, A.; Reig, P.; Doroshenko, V.
We present an X-ray timing and spectral analysis of the Be/X-ray binary SAX J2103.5+4545 at a time when the Be star's circumstellar disc had disappeared and thus the main reservoir of material available for accretion had extinguished. In this very low optical state, pulsed X-ray emission was detected at a level of LX ∼ 1033 e…
Constraining black hole masses in low-accreting active galactic nuclei using X-ray spectra
Titarchuk, L.; Gliozzi, M.; Jang, I. +1 more
In a recent work we demonstrated that a novel X-ray scaling method, originally introduced for Galactic black holes (BHs), can be reliably extended to estimate the mass of supermassive BHs accreting at a moderate to high level. Here we investigate the limits of applicability of this method to low-accreting active galactic nuclei (AGN), using a cont…
Spectral energy distributions of the BL Lac PKS 2155 - 304 from XMM-Newton
Bhagwan, Jai; Gupta, Alok C.; Papadakis, I. E. +1 more
We have used all 20 archival XMM-Newton observations of PKS 2155 - 304 with simultaneous X-ray and UV/optical data to study its long-term flux and spectral variability. We find significant variations, in all bands, on time-scales of years with an rms amplitude of ∼35-45 per cent, though the optical/UV variations are not correlated with those in th…
Masses of the components of SB2 binaries observed with Gaia - I. Selection of the sample and mass ratios of 20 new SB2s discovered with Sophie
Mazeh, T.; Tal-Or, L.; Halbwachs, J. -L. +7 more
In anticipation of the Gaia astrometric mission, a large sample of spectroscopic binaries has been observed since 2010 with the Sophie spectrograph at the Haute-Provence Observatory. Our aim is to derive the orbital elements of double-lined spectroscopic binaries (SB2s) with an accuracy sufficient finally to obtain the masses of the components wit…
The M 4 Core Project with HST - III. Search for variable stars in the primary field
van den Berg, M.; Anderson, J.; Milone, A. P. +14 more
We present the results of a photometric search for variable stars in the core of the Galactic globular cluster Messier 4 (M 4). The input data are a large and unprecedented set of deep Hubble Space Telescope WFC3 images (large programme GO-12911; 120 orbits allocated), primarily aimed at probing binaries with massive companions by detecting their …
A phenomenological model for the intracluster medium that matches X-ray and Sunyaev-Zel'dovich observations
Pfrommer, Christoph; Prada, Francisco; Zandanel, Fabio
Cosmological hydrodynamical simulations of galaxy clusters are still challenged to produce a model for the intracluster medium that matches all aspects of current X-ray and Sunyaev-Zel'dovich observations. To facilitate such comparisons with future simulations and to enable realistic cluster population studies for modelling e.g. non-thermal emissi…
The ultraviolet to far-infrared spectral energy distribution of star-forming galaxies in the redshift desert
Cepa, J.; Magdis, G.; Oteo, I. +6 more
We analyse the rest-frame ultraviolet (UV) to near-infrared (near-IR) spectral energy distribution (SED) of Lyman-break galaxies (LBGs), star-forming (SF) BzK (sBzK) and UV-selected galaxies at 1.5 ≲ z ≲ 2.5 in the COSMOS, GOODS-N and GOODS-S fields. Additionally, we complement the multiwavelength coverage of the galaxies located in the GOODS fiel…
X-ray observations of VY Scl-type nova-like binaries in the high and low state
Mukai, K.; Orio, M.; Shugarov, S. +1 more
Four VY Scl-type nova-like systems were observed in X-rays during both the low- and the high-optical states. We examined Chandra, ROSAT, Swift and Suzaku archival observations of BZ Cam, MV Lyr, TT Ari and V794 Aql. The X-ray flux of BZ Cam is higher during the low state, but there is no supersoft X-ray source (SSS) as hypothesized in previous art…
A new candidate Wolf-Rayet X-ray binary in NGC 253
Zezas, Andreas; Maccarone, Thomas J.; Hornschemeier, Ann +5 more
We have discovered a persistent, but highly variable X-ray source in the nearby starburst galaxy NGC 253. The source varies at the level of a factor of about 5 in count rate on time-scales of a few hours. Two long observations of the source with Chandra and XMM-Newton show suggestive evidence for the source having a period of about 14-15 hours, bu…