Search Publications
A new sample of X-ray selected narrow emission-line galaxies. II. Looking for True Seyfert 2
Watson, M. G.; Pons, E.
A sample of X-ray and optically selected narrow emission-line galaxies (769 sources) from the 3XMM catalogue cross-correlated with SDSS (DR9) catalogue has been studied. Narrow-emission line active galactic nuclei (AGN; type-2) have been selected on the basis of their emission line ratios and/or X-ray luminosity. We have looked for X-ray unobscure…
Unveiling the radio counterparts of two binary AGN candidates: J1108+0659 and J1131-0204
Bondi, M.; Piconcelli, E.; Pérez-Torres, M. A. +1 more
The sources SDSS J113126.08-020459.2 and SDSS J110851.04+065901.4 are two double-peaked [O III] emitting active galactic nuclei (AGNs), identified as candidate binary AGNs by optical and near infrared (NIR) observations. We observed the two sources with high resolution Very Long Baseline Interferometry (VLBI) using the European VLBI Network at 5 G…
A database of synthetic photometry in the GALEX ultraviolet bands for the stellar sources observed with the International Ultraviolet Explorer
Beitia-Antero, Leire; Gómez de Castro, Ana I.
Context. The Galaxy Evolution Explorer (GALEX) has produced the largest photometric catalogue of ultraviolet (UV) sources. As such, it has defined the new standard bands for UV photometry: the near UV band (NUV) and the far UV band (FUV). However, due to brightness limits, the GALEX mission has avoided the Galactic plane which is crucial for astro…
Slipping reconnection in a solar flare observed in high resolution with the GREGOR solar telescope
Strassmeier, K. G.; Schmidt, W.; Solanki, S. K. +23 more
A small flare ribbon above a sunspot umbra in active region 12205 was observed on November 7, 2014, at 12:00 UT in the blue imaging channel of the 1.5 m GREGOR telescope, using a 1 Å Ca II H interference filter. Context observations from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO), the Solar Optical Telescop…
Analysis of the WN star WR 102c, its WR nebula, and the associated cluster of massive stars in the Sickle Nebula
Sander, A.; Hamann, W. -R.; Oskinova, L. M. +3 more
Context. The massive Wolf-Rayet type star WR 102c is located near the
Three-dimensional distribution of hydrogen fluoride gas toward NGC 6334 I and I(N)
Abergel, A.; van der Wiel, M. H. D.; Naylor, D. A. +2 more
Context. The HF molecule has been proposed as a sensitive tracer of diffuse interstellar gas, while at higher densities its abundance could be influenced heavily by freeze-out onto dust grains.
Aims: We investigate the spatial distribution of a collection of absorbing gas clouds, some associated with the dense, massive star-forming core NGC 6…
Learning about stars from their colors
Allende Prieto, C.
Aims: We pose the question of how much information on the atmospheric parameters of late-type stars can be retrieved purely from color information using standard photometric systems.
Methods: We carried out numerical experiments using stellar fluxes from model atmospheres, injecting random noise before analyzing them. We examined the pre…
Transient effects in Herschel/PACS spectroscopy
Fadda, Dario; Appleton, Philip N.; Jacobson, Jeffery D.
Context. The Ge:Ga detectors used in the PACS spectrograph onboard the Herschel space telescope react to changes of the incident flux with a certain delay. This generates transient effects on the resulting signal which can be important and last for up to an hour.
Aims: The paper presents a study of the effects of transients on the detected si…
New orbital ephemerides for the dipping source 4U 1323-619: constraining the distance to the source
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
Context. 4U 1323-619 is a low mass X-ray binary system that shows type I X-ray bursts and dips. The most accurate estimation of the orbital period is 2.941923(36) h and a distance from the source that is lower than 11 kpc has been proposed.
Aims: We aim to obtain the orbital ephemeris, the orbital period of the system, as well as its derivati…
The warm absorber in the radio-loud quasar 4C +74.26
Costantini, E.; Di Gesu, L.
Outflows of photoionized gas are commonly detected in the X-ray spectra of Seyfert 1 galaxies. However, the evidence for this phenomenon in broad line radio galaxies, which are analogous to Seyfert 1 galaxies in the radio-loud regime, has so far been scarce. Here, we present the analysis of the X-ray absorption in the radio-loud quasar 4C +74.26. …