Search Publications
Spatio-temporal bands of coronal bright points and their relation to solar torsional oscillations
Tsinamdzgvrishvili, Tamar; Chargeishvili, B. B.; Shergelashvili, Bidzina M. +1 more
Using automatic processing of daily FITS files from SOHO_EIT, we studied the temporal evolution of the latitudinal distribution of bright coronal points from 1995 to 2020. The study revealed homogeneous and inhomogeneous components of the latitudinal distribution. The homogeneous component has cyclical variations with a significant phase shift com…
Rings and arcs around evolved stars - III. Physical conditions of the ring-like structures in the planetary nebula IC 4406 revealed by MUSE
Guerrero, M. A.; Toalá, J. A.; Ramos-Larios, G. +2 more
We present the analysis of Very Large Telescope Multi Unit Spectroscopic Explorer (MUSE) observations of the planetary nebula (PN) IC 4406. MUSE images in key emission lines are used to unveil the presence of at least five ring-like structures north and south of the main nebula of IC 4406. MUSE spectra are extracted from the rings to unambiguously…
A low-frequency pilot survey of southern H II regions in the vela constellation
Bourke, Tyler L.; Dickey, John M.; Wong, O. Ivy +3 more
Atomic ionized regions with strong continuum emission are often associated with regions of high-mass star formation and low-frequency (<2 GHz) observations of these regions are needed to help build star formation models. The region toward the Vela Supernova Remnant is particularly interesting as it is a complex structure of recent supernova exp…
The MOSDEF survey: towards a complete census of the z 2.3 star-forming galaxy population
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +16 more
We analyse the completeness of the MOSDEF survey, in which z ~ 2 galaxies were selected for rest-optical spectroscopy from well-studied HST extragalactic legacy fields down to a fixed rest-optical magnitude limit (HAB = 24.5). The subset of z ~ 2 MOSDEF galaxies with high signal-to-noise (S/N) emission-line detections analysed in previo…
A transient ultraluminous X-ray source in NGC 55
Cusumano, G.; Wolter, A.; Pinto, C. +14 more
Ultraluminous X-ray sources (ULXs) are a class of accreting compact objects with X-ray luminosities above 1039 erg s-1 . The average number of ULXs per galaxy is still not well-constrained, especially given the uncertainty on the fraction of ULX transients. Here, we report the identification of a new transient ULX in the gala…
Dark Energy Camera photometry reveals extra-tidal stars around the Milky Way globular cluster NGC 6864 (M75)
Piatti, Andrés E.
Globular clusters are prone to lose stars while moving around the Milky Way. These stars escape the clusters and are distributed throughout extended envelopes or tidal tails. However, such extra-tidal structures are not observed in all globular clusters, and yet there are no structural or dynamical parameters that can predict their presence or abs…
Simple interpretation of the seemingly complicated X-ray spectral variation of NGC 5548
Sugawara, Yasuharu; Ebisawa, Ken; Mizumoto, Misaki +1 more
NGC 5548 is a very well-studied Seyfert 1 galaxy in broad wavelengths. Previous multiwavelength observation campaigns have indicated that its multiple absorbers are highly variable and complex. A previous study applied a two-zone partial covering model with different covering fractions to explain the complex X-ray spectral variation and reported a…
Earth through the looking glass: how frequently are we detected by other civilizations through photometric microlensing?
Robin, A. C.; Awiphan, S.; Kerins, E. +5 more
Microlensing is proving to be one of the best techniques to detect distant, low-mass planets around the most common stars in the Galaxy. In principle, Earth's microlensing signal could offer the chance for other technological civilizations to find the Earth across Galactic distances. We consider the photometric microlensing signal of Earth to othe…
Comparing reflection and absorption models for the soft X-ray variability in the NLS1 AGN UGC 11763
Jiang, Jiachen; Gallo, Luigi C.; Grupe, Dirk +1 more
We present a spectral analysis of two XMM-Newton observations of the narrow-line Seyfert 1 galaxy UGC 11763. UGC 11763 shows very different soft X-ray spectral shapes in the two observations separated by 12 yr. Three spectral models are considered to explain the multi-epoch X-ray variability of UGC 11763, one based on the relativistic disc reflect…
On the physical size of the Milky Way globular cluster NGC 7089 (M2)
Piatti, Andrés E.
We study the outer regions of the Milky Way globular cluster NGC 7089 based on new Dark Energy Camera observations. The resulting background-cleaned stellar density profile reveals the existence of an extended envelope. We confirm previous results that cluster stars are found out up to ~1° from the cluster's centre, which is nearly three times the…