Search Publications
A two-sided but significantly beamed jet in the supercritical accretion quasar IRAS F11119+3257
Paragi, Zsolt; Yang, Jun; An, Tao +3 more
Highly accreting quasars are quite luminous in the X-ray and optical regimes; while, they tend to become radio quiet and have optically thin radio spectra. Among the known quasars, IRAS F11119+3257 is a supercritical accretion source because it has a bolometric luminosity slightly above the Eddington limit and extremely powerful X-ray outflows. To…
Deciphering the nature of the pulsar wind nebula CTB 87 with XMM-Newton
Safi-Harb, S.; Kothes, R.; Bucciantini, N. +5 more
CTB 87 (G74.9+1.2) is an evolved supernova remnant (SNR) which hosts a peculiar pulsar wind nebula (PWN). The X-ray peak is offset from that observed in radio and lies towards the edge of the radio nebula. The putative pulsar, CXOU J201609.2+371110, was first resolved with Chandra and is surrounded by a compact and a more extended X-ray nebula. He…
Asymptotic kinematics of globular clusters: The emergence of a Tully-Fisher relation
Hernandez, X.; Lara-D I, A. J.
Using a recent homogeneous sample of 40 high-quality velocity dispersion profiles for Galactic globular clusters, we study the regime of low gravitational acceleration relevant to the outskirts of these systems. We find that a simple empirical profile having a central Gaussian component and a constant large-radius asymptote, σ∞, accurat…
Deuterium fractionation of nitrogen hydrides: detections of NHD and ND2
Pagani, L.; Kobayashi, K.; Hily-Blant, P. +5 more
Although ammonia is an abundant molecule commonly observed towards the dense interstellar medium, it has not yet been established whether its main formation route is from gas-phase ion-molecule reactions or grain-surface hydrogen additions on adsorbed nitrogen atoms. Deuterium fractionation can be used as a tool to constrain formation mechanisms. …
3D structure of the H II region Sh2-235 from tunable-filter optical observations
Wiebe, D. S.; Moiseev, A. V.; Kirsanova, M. S. +2 more
We present observations of the H α, H β, [S II] λλ6716, 6731 and [N II] λ6583 emission lines in the galactic H II region Sh2-235 with the Mapper of Narrow Galaxy Lines (MaNGaL), a tunable filter at the 1-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We show that the H II region is obscured by neutral mate…
Dust in the Wolf-Rayet nebula M 1-67
Toalá, J. A.; Jiménez-Hernández, P.; Arthur, S. J.
The Wolf-Rayet nebula M 1-67 around WR 124 is located above the Galactic plane in a region mostly empty of interstellar medium, which makes it the perfect target to study the mass-loss episodes associated with the late stages of massive star evolution. Archive photometric observations from Wide-field Infrared Survey Explorer(WISE), Spitzer (MIPS),…
The rich lack close neighbours: the dependence of blue-straggler fraction on metallicity
Wyse, Rosemary F. G.; Kratter, Kaitlin M.; Moe, Maxwell
Blue-straggler stars (BSS) have been identified in star clusters and in field populations in our own Milky Way galaxy and in its satellite galaxies. They manifest as stars bluer and more luminous than the dominant old population, and usually have a spatial distribution that follows the old population. Their progenitors are likely to have been clos…
Machine learning applied to multifrequency data in astrophysics: blazar classification
Arsioli, B.; Dedin, P.
The study of machine learning (ML) techniques for the autonomous classification of astrophysical sources is of great interest, and we explore its applications in the context of a multifrequency data-frame. We test the use of supervised ML to classify blazars according to its synchrotron peak frequency, either lower or higher than 1015 H…
Extremely precise age and metallicity of the open cluster NGC 2506 using detached eclipsing binaries
Grundahl, F.; Knudstrup, E.; Lund, M. N. +10 more
Accurate stellar parameters of stars in open clusters can help constrain models of stellar structure and evolution. Here, we wish to determine the age and metallicity content of the open cluster NGC 2506. To this end, we investigated three detached eclipsing binaries (DEBs; V2032, V4, and V5) for which we determined their masses and radii, as well…
Wolf-Rayet stars in M 81 using GTC/OSIRIS: seven new detections, analysis, and classification of the full sample
Alvarez, C.; Toalá, J. A.; Gómez-González, V. M. A. +3 more
We report the detection of seven new Wolf-Rayet (WR) star locations in M 81 using the Multi-Object Spectrograph of the OSIRIS instrument at Gran Telescopio Canarias. These detections are the result of a follow-up of an earlier study using the same instrumental set-up that resulted in the detection of 14 WR locations. We analyse the entire sample o…