Search Publications
A DECam view of the diffuse dwarf galaxy Crater II: the colour-magnitude diagram
Walker, A. R.; Stetson, P. B.; Bono, G. +12 more
We present a deep Blanco/DECam colour-magnitude diagram (CMD) for the large but very diffuse Milky Way satellite dwarf galaxy Crater II. The CMD shows only old stars with a clearly bifurcated subgiant branch (SGB) that feeds a narrow red giant branch. The horizontal branch (HB) shows many RR Lyrae and red HB stars. Comparing the CMD with [Fe/H] = …
Galaxy structural analysis with the curvature of the brightness profile
Ferrari, Fabricio; Lucatelli, Geferson
In this work, we introduce the curvature of a galaxy brightness profile to identify its structural subcomponents in a non-parametrically fashion. Bulges, bars, discs, lens, rings, and spiral arms are key to understand the formation and evolution path the galaxy undertook. Identifying them is also crucial for morphological classification of galaxie…
The kinematics of Galactic disc white dwarfs in Gaia DR2
Kilic, Mukremin; Rowell, Nicholas
We present an analysis of the kinematics of Galactic disc white dwarf (WD) stars in the solar neighbourhood using data from Gaia Data Release 2. Selection of WDs based on parallax provides the first large, kinematically unbiased sample of solar neighbourhood WDs to date. Various classical properties of the solar neighbourhood kinematics have been …
Sub-millimetre non-contaminated detection of the disc around TWA 7 by ALMA
de Gregorio-Monsalvo, I.; Bayo, A.; Schreiber, M. R. +9 more
Debris discs can be seen as the leftovers of giant planet formation and the possible nurseries of rocky planets. While M-type stars outnumber more massive stars we know very little about the time evolution of their circumstellar discs at ages older than ∼10 Myr. Sub-millimetre observations are best to provide first order estimates of the available…
Volume uncertainty assessment method of asteroid models from disc-integrated visual photometry
Bartczak, P.; Dudziński, G.
The need for more accurate asteroid models is perhaps secondary to the need to measure their quality. The uncertainties of models' parameters propagate to quantities like volume or density - the most important and informative properties of asteroids - affecting conclusions about their physical nature. Our knowledge on shapes and spins of small Sol…
Ground-based observation of ZZ Ceti stars and the discovery of four new variables
Kepler, S. O.; Romero, Alejandra D.; Koester, D. +7 more
We perform ground-based photometric observations of 22 DA white dwarf stars, 10 already known ZZ Cetis and 12 candidates with atmospheric parameters inside the classical instability strip. We report on the discovery of four new variable DA white dwarf stars. Two objects are near the middle of the instability strip, SDSS J082804.63+094956.6 and SDS…
A hyper-runaway white dwarf in Gaia DR2 as a Type Iax supernova primary remnant candidate
Ruffini, Nicholas J.; Casey, Andrew R.
Observations of stellar remnants linked to Type Ia and Type Iax supernovae are necessary to fully understand their progenitors. Multiple progenitor scenarios predict a population of kicked donor remnants and partially burnt primary remnants, both moving with relatively high velocity. But only a handful of examples consistent with these two predict…
DW Cancri in X-rays
Conversi, L.; Nucita, A. A.; Licchelli, D.
We report on the XMM-Newton observation of DW Cnc, a candidate intermediate polar candidate whose historical optical light curve shows the existence of periods at ≃38, ≃86, and ≃69 min, which were interpreted as the white dwarf spin, the orbital and the spin-orbit beat periodicities. By studying the 0.3-10 keV light curves, we confirm the existenc…
Pulse frequency fluctuations of magnetars
Serim, M. M.; Şahiner, Ş.; Inam, S. ć. +2 more
Using RXTE, Chandra, XMM-Newton and Swift observations, we construct the power spectra and torque noise strengths of magnetars for the first time. For some of the sources, on time-scales of months to years, we measure strong red noise that might be a consequence of their outbursts. We compare the noise strengths of magnetars with those of radio pu…
The host galaxies of luminous type 2 AGNs at z ∼ 0.3-0.4
Koekemoer, A. M.; Carrera, F. J.; Huertas-Company, M. +7 more
We study the morphological and structural properties of the host galaxies associated with 57 optically selected luminous type 2 active galactic nuclei (AGNs) at z ∼ 0.3-0.4: 16 high-luminosity Seyfert 2 [HLSy2, 8.0 ≤ log(L_[O III]/L_{⊙}) < 8.3] and 41 obscured [QSO2, log(L_[O III]/L_{⊙})≥ 8.3] quasars. With this work, the total number of QSO2s …