Search Publications
The host galaxy of GRB 980425/SN1998bw: a collisional ring galaxy
Le Floc'h, E.; Pian, E.; Bournaud, F. +8 more
We report Giant Metrewave Radio Telescope (GMRT), Very Large Telescope (VLT), and Spitzer Space Telescope observations of ESO 184-G82, the host galaxy of GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a gas-rich, star-forming galaxy with a star…
A study of cool white dwarfs in the Sloan Digital Sky Survey Data Release 12
Kepler, S. O.; Koester, D.; Ourique, G. +2 more
In this work, we study white dwarfs where 30 000 K > T_{eff} > 5000 K to compare the differences in the cooling of DAs and non-DAs and their formation channels. Our final sample is composed by nearly 13 000 DAs and more than 3 000 non-DAs that are simultaneously in the SDSS DR12 spectroscopic database and in the Gaia survey DR2. We present t…
The dust in M31
Dalcanton, J. J.; Griffin, M. J.; Smith, M. W. L. +6 more
We have analysed Herschel observations of M31, using the PPMAP procedure. The resolution of PPMAP images is sufficient (∼ 31 pc on M31) that we can analyse far-IR dust emission on the scale of giant molecular clouds. By comparing PPMAP estimates of the far-IR emission optical depth at 300 µ m (τ_{{300}}), and the near-IR extinction optical d…
A-type stars in the Canada-France Imaging Survey - II. Tracing the height of the disc at large distances with Blue Stragglers
Laporte, Chervin F. P.; McConnachie, Alan W.; Malhan, Khyati +7 more
We present the kinematics of Blue Straggler (BS) stars identified in the Canada-France Imaging Survey (CFIS), covering 4000 deg2 on the sky in the u band. The BSs sample, characterized through CFIS and Pan-STARRS photometry, has been kinematically decomposed into putative halo and disc populations after cross-matching with Gaia astromet…
Metallicity dependence of the Hercules stream in Gaia/RAVE data - explanation by non-closed orbits
Hattori, Kohei; Kumamoto, Jun; Tagawa, Hiromichi +4 more
The origin of the Hercules stream, the most prominent velocity substructure in the Solar neighbour disc stars, is still under debate. Recent accurate measurements of position, velocity, and metallicity provided by Tycho Gaia Astrometric Solution (TGAS) and RAdial Velocity Experiments (RAVE) have revealed that the Hercules stream is most clearly se…
Evidence for mass accretion driven by spiral shocks onto the white dwarf in SDSS J123813.73-033933.0
Reichart, D. E.; Wang, L.; Knigge, C. +21 more
We present high-time-resolution photometry and phase-resolved spectroscopy of the short-period ({P_orb}= 80.52 min) cataclysmic variable SDSS J123813.73-033933.0, observed with the Hubble Space Telescope (HST), the Kepler/K2 mission, and the Very Large Telescope (VLT). We also report observations of the first detected superoutburst. SDSS J1238-033…
Variable dust emission by WC type Wolf-Rayet stars observed in the NEOWISE-R survey
Williams, P. M.
Photometry at 3.4 and 4.6 {µ m} of 128 Population I WC type Wolf-Rayet stars in the Galaxy and 12 in the Large Magellanic Cloud (LMC) observed in the WISE NEOWISE-R survey was searched for evidence of circumstellar dust emission and its variation. Infrared spectral energy distributions (SEDs) were assembled, making use of archival r, i, Z, a…
K2-140b and K2-180b - Characterization of a hot Jupiter and a mini-Neptune from the K2 mission
Kuzuhara, M.; Alonso, R.; Erikson, A. +40 more
We report the independent discovery and characterization of two K2 planets: K2-180b, a mini-Neptune-sized planet in an 8.9-d orbit transiting a V = 12.6 mag, metal-poor ([Fe/H] = -0.65 ± 0.10) K2V star in K2 campaign 5; K2-140b, a transiting hot Jupiter in a 6.6-d orbit around a V = 12.6 mag G6V ([Fe/H] = + 0.10 ± 0.10) star in K2 campaign 10. Our…
High frequencies in TESS A-F main-sequence stars
Balona, L. A.; Cunha, M. S.; Holdsworth, D. L.
The driving mechanism for high-frequency oscillations in some chemically peculiar Ap stars, the rapidly oscillating Ap stars (roAp stars), is not understood. The Transiting Exoplanet Survey Satellite mission (TESS) data provide an ideal opportunity to extend the number of roAp stars that might provide further clues to address this problem. From an…
Spectroscopic study of two new super Li-rich red clump K giants
Reddy, Bacham E.; Kumar, Yerra Bharat; Singh, Raghubar
In this paper, we report the discovery of two new super Li-rich K giants: HD 24960 and TYC 1751-1713-1. Based on high-resolution (R ≈ 60 000) spectroscopy, we have derived Li abundance of A(Li) ≈ 4.0 dex for both stars. Other elemental abundances are normal of typical K giants. Low ratios of [C/N] ≤ -0.25 and 12C/13C ≤ 10 sug…