Search Publications
Does the solar granulation change with the activity cycle?
Ichimoto, K.; Utz, D.; Hanslmeier, A. +1 more
Context. Knowledge of the variation of the solar granulation properties (contrast and scale) with the 11-yr activity cycle is useful for a better understanding of the interaction between magnetic field and convection at global or local scales. A varying granulation may also contribute to irradiance variations and affect the p-mode damping rates an…
Gathering dust: A galaxy-wide study of dust emission from cloud complexes in NGC 300
Forbrich, J.; Riener, M.; Faesi, C. M. +1 more
Aims: We use multi-band observations by the Herschel Space Observatory to study the dust emission properties of the nearby spiral galaxy NGC 300. We compile a first catalogue of the population of giant dust clouds (GDCs) in NGC 300, including temperature and mass estimates, and give an estimate of the total dust mass of the galaxy.
Metho…
Possible substellar companions in low-mass eclipsing binaries: GU Bootis and YY Geminorum
Wolf, M.; Mašek, M.; Kučáková, H. +10 more
We present the next results of our long-term observational project to analyze the variations in the orbital periods of low-mass eclipsing binaries. About 70 new precise mid-eclipse times recorded with a CCD were obtained for two eclipsing binaries with short orbital periods: GU Boo (P = 0.d49) and YY Gem (0.d81). Observed-m…
Optical and UV surface brightness of translucent dark nebulae. Dust albedo, radiation field, and fluorescence emission by H2
Leinert, Ch.; Haas, M.; Väisänen, P. +4 more
Context. Dark nebulae display a surface brightness because dust grains scatter light of the general interstellar radiation field (ISRF). High-galactic-latitudes dark nebulae are seen as bright nebulae when surrounded by transparent areas which have less scattered light from the general galactic dust layer.
Aims: Photometry of the bright dark …
Impact of measurement errors on the inferred stellar asteroseismic ages. Statistical models for intermediate age main sequence and red giant branch stars
Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G. +1 more
Aims: We aim to perform a theoretical investigation on the direct impact of measurement errors in the observational constraints on the recovered age for stars in main sequence (MS) and red giant branch (RGB) phases. We assumed that a mix of classical (effective temperature Teff and metallicity [Fe/H]) and asteroseismic (Δν and ν
The cosmological analysis of X-ray cluster surveys. IV. Testing ASpiX with template-based cosmological simulations
Pierre, M.; Faccioli, L.; Clerc, N. +5 more
Context. This paper is the fourth of a series evaluating the ASpiX cosmological method, based on X-ray diagrams, which are constructed from simple cluster observable quantities, namely: count rate (CR), hardness ratio (HR), core radius (rc), and redshift.
Aims: Following extensive tests on analytical toy catalogues (Paper III), we …
The Seahorse Nebula: New views of the filamentary infrared dark cloud G304.74+01.32 from SABOCA, Herschel, and WISE
Miettinen, O.
Context. Filamentary molecular clouds, such as many of the infrared dark clouds (IRDCs), can undergo hierarchical fragmentation into substructures (clumps and cores) that can eventually collapse to form stars.
Aims: We aim to determine the occurrence of fragmentation into cores in the clumps of the filamentary IRDC G304.74+01.32 (hereafter, G…
Reconstruction of the two-dimensional gravitational potential of galaxy clusters from X-ray and Sunyaev-Zel'dovich measurements
Hurier, G.; Eckert, D.; Meneghetti, M. +8 more
Context. The mass of galaxy clusters is not a direct observable, nonetheless it is commonly used to probe cosmological models. Based on the combination of all main cluster observables, that is, the X-ray emission, the thermal Sunyaev-Zel'dovich (SZ) signal, the velocity dispersion of the cluster galaxies, and gravitational lensing, the gravitation…
Galactic or extragalactic chemical tagging for NGC 3201?. Discovery of an anomalous CN-CH relation
Dias, B.; Saker, L.; Shokry, A. +2 more
Context. The origin of the globular cluster (GC) NGC 3201 is under debate. Its retrograde orbit points to an extragalactic origin, but no further chemical evidence supports this idea. Light-element chemical abundances are useful to tag GCs and can be used to shed light on this discussion.
Aims: Recently it was shown that the CN and CH indices…
Ultraluminous X-ray sources: new distance indicators?
Różańska, A.; Madej, J.; Bresler, K. +2 more
Aims: In this paper we fit the NuSTAR and XMM-Newton data of three sources: NGC 7793 P13, NGC5907 ULX1, and Circinus ULX5.
Methods: Our single model contains emission from a non-spherical system: a neutron star plus an accretion disk directed towards the observer.
Results: We obtained a very good fit with the reduced χ2 p…