Search Publications
On the distance to the Ophiuchus star-forming region
Mamajek, E. E.
The Ophiuchus molecular cloud complex has produced in Lynds 1688 the richest known embedded cluster within ∼300 pc of the Sun. Unfortunately, distance estimates to the Oph complex vary by nearly ∼40% (∼120-165 pc). Here I calculate a new independent distance estimate of 135 ± 8 pc to this benchmark star-forming region based on Hipparcos trigonomet…
Speckle observations with PISCO in Merate: IV. Astrometric measurements of visual binaries in 2005
Scardia, M.; Prieur, J. -L.; Pansecchi, L. +6 more
We present relative astrometric measurements of visual binaries made during the second semester of 2005, with the speckle camera PISCO at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. The purpose of this long term program is to impro…
New absolute magnitude calibrations for detached binaries
Demircan, O.; Eker, Z.; Soydugan, F. +6 more
Lutz-Kelker bias corrected absolute magnitude calibrations for the detached binary systems with main-sequence components are presented. The absolute magnitudes of the calibrator stars were derived at intrinsic colours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As for the calibrator stars, 44 detached binaries wer…
A revisit to agglomerates of early-type Hipparcos stars
Caballero, J. A.; Dinis, L.
% We study the spatial structure and sub-structure of regions rich in {Hipparcos} stars with blue B_T-V_T colours. These regions, which comprise large stellar complexes, OB associations, and young open clusters, are tracers of on-going star formation in the Galaxy. The DBSCAN (Density-Based Spatial Clustering of Applications with Noise) data clust…
Preliminary orbital elements of six visual binary stars
Scardia, M.; Prieur, J. -L.; Pansecchi, L. +1 more
Preliminary new orbital elements were computed for the visual binary stars A 1 - ADS 1345, A 2629 - ADS 3610, BU 560 - ADS 4371, STF 3115 - ADS 4376, STF 1426 AB - ADS 7730 and STF 2437 - ADS 11956. Using Straizys and Kuriliene's data, we derived new formulae for computing dynamical parallaxes for luminosity classes IV and V. The values found for …
Extragalactic X-ray surveys: AGN physics and evolution
Comastri, A.; Brusa, M.
We review the most important findings on AGN physics and cosmological evolution as obtained by extragalactic X-ray surveys and associated multiwavelength observations. We briefly discuss the perspectives for future enterprises and in particular the scientific case for an extremely deep (2-3 Ms) XMM survey
The Planck cluster survey
Arnaud, M.; Bartlett, J. G.; Chamballu, A. +2 more
The Planck Satellite will survey the entire sky in 9 millimeter/submillimeter bands and detect thousands of galaxy clusters via their thermal Sunyaev-Zel'dovich (SZ) effect. The unprecedented volume of the survey will permit the construction of a unique catalog of massive clusters out to redshifts of order unity. We describe the expected contents …
XMM-Newton and broad iron lines
Fabian, A. C.
Iron line emission is common in the X-ray spectra of accreting black holes. When the line emission is broad or variable then it is likely to originate from close to the black hole. X-ray irradiation of the accretion flow by the power-law X-ray continuum produces the X-ray `reflection' spectrum which includes the iron line. The shape and variabilit…
X-rays from young stars: A summary of highlights from the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)
Güdel, M.
The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST) is a survey of the nearest large star-forming region, the Taurus Molecular Cloud (TMC), making use of all instruments on board the XMM-Newton X-ray observatory. The survey, presently still growing, has provided unprecedented spectroscopic results from nearly every observed T Tauri…
Extragalactic archeology in integrated light: A test case with NGC 4030
Peletier, R.; Ocvirk, P.; Lançon, A.
We reconstruct the age-velocity distribution of the central region of the Sbc galaxy NGC4030, by applying STECKMAP to very high quality WHT/ISIS data. We find that the main component is a relatively young (≈ 2 Gyr) bulge with a ≈ 100 km/s velocity dispersion. The best fit solution also shows a superimposed young, kinematically cold (σ_{v}∼ 30 km/s…