Search Publications
Normal and counter Evershed flows in the photospheric penumbra of a sunspot. SPINOR 2D inversions of Hinode-SOT/SP observations
Solanki, S. K.; Lagg, A.; Jurčák, J. +2 more
Context. The Evershed effect, a nearly horizontal outflow of material seen in the penumbrae of sunspots in the photospheric layers, is a common characteristic of well-developed penumbrae, but is still not well understood. Even less is known about photospheric horizontal inflows in the penumbra, also known as counter Evershed flows.
Aims: Here…
The nearby interstellar medium toward α Leo. UV observations and modeling of a warm cloud within hot gas
Jenkins, Edward B.; Gry, Cecile
Aims: Our aim is to characterize the conditions in the nearest interstellar cloud.
Methods: We analyze interstellar absorption features in the full UV spectrum of the nearby (d = 24 pc) B8 IVn star
Chemical abundances of two extragalactic young massive clusters
Hernandez, Svea; Kaper, Lex; Larsen, Søren +2 more
Aims: We use integrated-light spectroscopic observations to measure metallicities and chemical abundances for two extragalactic young massive star clusters (NGC 1313-379 and NGC 1705-1). The spectra were obtained with the X-shooter spectrograph on the ESO Very Large Telescope.
Methods: We compute synthetic integrated-light spectra, based…
Calibration of the photometric G passband for Gaia Data Release 1
Maíz Apellániz, J.
Context. On September 2016 the first data from Gaia were released (DR1). The first release included photometry for over 109 sources in the very broad G system.
Aims: The aims here are to test the correspondence between G magnitudes in DR1 and the synthetic equivalents derived using spectral energy distributions from observed and mo…
Inflowing gas onto a compact obscured nucleus in Arp 299A. Herschel spectroscopic studies of H2O and OH
González-Alfonso, E.; Aalto, S.; Fischer, J. +1 more
Aims: We probe the physical conditions in the core of Arp 299A and try to put constraints on the nature of its nuclear power source.
Methods: We used Herschel Space Observatory far-infrared and submillimeter observations of H2O and OH rotational lines in Arp 299A to create a multi-component model of the galaxy. In doing this, …
A re-analysis of the NuSTAR and XMM-Newton broad-band spectrum of Serpens X-1
Sanna, A.; Di Salvo, T.; Burderi, L. +4 more
Context. High-resolution X-ray spectra of neutron star low-mass X-ray binaries (LMXBs) in the energy range 6.4-6.97 keV are often characterized by the presence of Kα transition features of iron at different ionization stages. Since these lines are thought to originate by reflection of the primary Comptonization spectrum over the accretion disk, th…
(Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. IV. Physical properties derived from spectral energy distributions
Ilbert, O.; Smolčić, V.; Murphy, E. J. +10 more
Context. Submillimetre galaxies (SMGs) in the early Universe are potential antecedents of the most massive galaxies we see in the present-day Universe. An important step towards quantifying this galactic evolutionary connection is to investigate the fundamental physical properties of SMGs, such as their stellar mass content (M⋆) and sta…
Studying the accretion geometry of EXO 2030+375 at luminosities close to the propeller regime
Wilms, J.; Pottschmidt, K.; Kretschmar, P. +10 more
The Be X-ray binary EXO 2030+375was in an extended low-luminosity state during most of 2016. We observed this state with NuSTARand Swift, supported by INTEGRALobservations and optical spectroscopy with the Nordic Optical Telescope (NOT). We present a comprehensive spectral and timing analysis of these data here to study the accretion geometry and …
Possible regular phenomena in EXO 2030+375
Makishima, Kazuo; Santangelo, Andrea; Moritani, Yuki +4 more
In the last 10 yr, since its last giant outburst in 2006, regular X-ray outbursts (type I) were detected every periastron passage in the Be X-ray binary EXO 2030+375. Recently, however, it was reported that the source started to show a peculiar behavior: its X-ray flux decreased significantly and type I outbursts were missed in several cases. At t…
The accretion environment of supergiant fast X-ray transients probed with XMM-Newton
Bernardini, F.; Romano, P.; Ferrigno, C. +3 more
Context. Supergiant fast X-ray (SFXT) transients are a peculiar class of supergiant X-ray binaries characterized by a remarkable variability in the X-ray domain, widely ascribed to accretion from a clumpy stellar wind.
Aims: In this paper we performed a systematic and homogeneous analysis of the sufficiently bright X-ray flares observed with …