Search Publications
Understanding type Ia supernovae through their U-band spectra
Rubin, D.; Aldering, G.; Barbary, K. +40 more
Context. Observations of type Ia supernovae (SNe Ia) can be used to derive accurate cosmological distances through empirical standardization techniques. Despite this success neither the progenitors of SNe Ia nor the explosion process are fully understood. The U-band region has been less well observed for nearby SNe, due to technical challenges, bu…
Occurrence and persistence of magnetic elements in the quiet Sun
Gošić, M.; Bellot Rubio, L.; Giannattasio, F. +3 more
Context. Turbulent convection efficiently transports energy up to the solar photosphere, but its multi-scale nature and dynamic properties are still not fully understood. Several works in the literature have investigated the emergence of patterns of convective and magnetic nature in the quiet Sun at spatial and temporal scales from granular to glo…
Modelling of integrated-light spectra from the optical to the near-infrared: the globular cluster G280 in M31
Larsen, S. S.; Pugliese, G.; Brodie, J. P.
Context. In previous papers, we introduced our method for measuring chemical abundances from integrated-light spectra of globular clusters and applied it to a variety of extragalactic star clusters. Our work so far, however, has concentrated primarily on the optical range 4200 Å -6200 Å.
Aims: Here we extend our analysis technique to the infr…
Oxygen and silicon abundances in Cygnus OB2. Chemical homogeneity in a sample of OB slow rotators
Herrero, A.; Comerón, F.; Simón-Díaz, S. +3 more
Context. Cygnus OB2 is a rich OB association in the Galaxy located at only ∼1.4 kpc from us which has experienced intense star formation in the last 20-25 Myr. Its stellar population shows a correlation between age and Galactic longitude. Exploring the chemical composition of its stellar content we will be able to check the degree of homogeneity o…
The seven sisters DANCe. III. Projected spatial distribution
Bertin, E.; Bouy, H.; Sarro, L. M. +6 more
Context. Membership analyses of the DANCe and Tycho + DANCe data sets provide the largest and least contaminated sample of Pleiades candidate members to date.
Aims: We aim at reassessing the different proposals for the number surface density of the Pleiades in the light of the new and most complete list of candidate members, and inferring the…
A combined Compton and coded-aperture telescope for medium-energy gamma-ray astrophysics
Boggs, Steven E.; Zoglauer, Andreas; Galloway, Michelle +1 more
A future mission in medium-energy gamma-ray astrophysics would allow for many scientific advancements, such as a possible explanation for the excess positron emission from the Galactic center, a better understanding of nucleosynthesis and explosion mechanisms in Type Ia supernovae, and a look at the physical forces at play in compact objects such …
Refining the origins of the gamma-ray binary 1FGL J1018.6-5856
Marcote, B.; Edwards, P. G.; Paredes, J. M. +2 more
Context. Gamma-ray binaries are systems composed of a massive star and a compact object that exhibit emission from radio to very high energy gamma rays. They are ideal laboratories to study particle acceleration and a variety of physical processes that vary as a function of the orbital phase.
Aims: We aim to study the radio emission of the ga…
Scaling of X-ray spectral properties of a black hole in the Seyfert 1 galaxy NGC7469
Titarchuk, Lev; Seifina, Elena; Ugolkova, Lyubov
We present our analysis of X-ray spectral properties observed from the Seyfert 1 galactic nucleus NGC 7469 using the Rossi X-ray Timing Explorer (RXTE) and Advanced Satellite for Cosmology and Astrophysics mission (ASCA) observations. We demonstrate strong observational evidence that NGC 7469 undergoes spectral transitions from the low hard state …
The spatial extent of polycyclic aromatic hydrocarbons emission in the Herbig star HD 179218
Rebolo, R.; Wolf, S.; Taha, A. S. +7 more
Aim. We investigate, in the mid-infrared, the spatial properties of the polycyclic aromatic hydrocarbons (PAHs) emission in the disk of HD 179218, an intermediate-mass Herbig star at 300 pc.
Methods: We obtained mid-infrared images in the PAH-1, PAH-2 and Si-6 filters centered at 8.6, 11.3, and 12.5 µm, and N-band low-resolution spectra…
Galaxy evolution in groups. NGC 3447/NGC 3447A: the odd couple in LGG 225
Plana, H.; Marino, A.; Mazzei, P. +3 more
Context. Local Group (LG) analogs (LGAs) are galaxy associations dominated by a few bright spirals reminiscent of the LG. The NGC 3447/NGC 3447A system is a member of the LGG 225 group, a nearby LGA. This system is considered a physical pair composed of an intermediate-luminosity late-type spiral, NGC 3447 itself, and an irregular companion, NGC 3…