Search Publications
An extragalactic chromosome map: the intermediate-age SMC cluster Lindsay 1
Dalessandro, E.; Salaris, M.; Cabrera-Ziri, I. +8 more
The discovery of star-to-star abundance variations (a.k.a. multiple populations - MPs) within globular clusters (GCs), which are generally not found in the field or in lower mass open clusters, has led to a search for the unique property of GCs that allow them to host this phenomenon. Recent studies have shown that MPs are not limited to the ancie…
GMRT 610 MHz observations of galaxy clusters in the ACT equatorial sample
Hilton, Matt; Sifón, Cristóbal; Bond, J. Richard +11 more
We present Giant Metrewave Radio Telescope (GMRT) 610 MHz observations of 14 Atacama Cosmology Telescope (ACT) clusters, including new data for nine. The sample includes 73 per cent of ACT equatorial clusters with M500 > 5 × 1014 M⊙. We detect diffuse emission in three of these (27^{+20}_{-14} per cent): we dete…
Absolute properties of RU Cnc revisited: an active RS CVn-type eclipsing binary with red giant branch and main-sequence components
Koçak, D.; Yakut, K.; Çokluk, K. A. +3 more
We present observations and analysis of an RS CVn-type double-lined eclipsing binary system, RU Cnc. The system has been observed for over a century. High-quality long-cadence observations, newly obtained from the Kepler K2 C5 and C18 campaigns, and two radial velocity curves were combined and analysed simultaneously, assuming a multispot model. T…
The subgiant HR 7322 as an asteroseismic benchmark star
Huber, Daniel; Stokholm, Amalie; White, Timothy R. +5 more
We present an in-depth analysis of the bright subgiant HR 7322 (KIC 10005473) using Kepler short-cadence photometry, optical interferometry from CHARA, high-resolution spectra from SONG, and stellar modelling using GARSTEC grids, and the Bayesian grid-fitting algorithm BASTA. HR 7322 is only the second subgiant with high-quality Kepler asteroseism…
Testing the warmness of dark matter
Nunes, Rafael C.; Kumar, Suresh; Yadav, Santosh Kumar
Dark matter (DM) as a pressureless perfect fluid provides a good fit of the standard Λ cold dark matter (ΛCDM) model to the astrophysical and cosmological data. In this paper, we investigate two extended properties of DM: a possible time dependence of the equation of state of DM via Chevallier-Polarski-Linder parametrization, wdm = w
Searching for fast extragalactic X-ray transients in Chandra surveys
Bauer, F. E.; Brandt, W. N.; Xue, Y. Q. +4 more
Recent works have discovered two fast (≈10 ks) extragalactic X-ray transients in the Chandra Deep Field-South (CDF-S XT1 and XT2). These findings suggest that a large population of similar extragalactic transients might exist in archival X-ray observations. We develop a method that can effectively detect such transients in a single Chandra exposur…
The XUV irradiation and likely atmospheric escape of the super-Earth π Men c
Wheatley, Peter J.; Bourrier, Vincent; Ehrenreich, David +1 more
π Men c was recently announced as the first confirmed exoplanet from the TESS mission. The planet has a radius of just 2 R⊕ and it transits a nearby Sun-like star of naked-eye brightness, making it the ideal target for atmospheric characterization of a super-Earth. Here we analyse archival ROSAT and Swift observations of π Men in order …
OGLE-2017-BLG-1186: first application of asteroseismology and Gaussian processes to microlensing
Kim, S. -L.; Lee, C. -U.; Bennett, D. P. +102 more
We present the analysis of the event OGLE-2017-BLG-1186 from the 2017 Spitzer microlensing campaign. This is a remarkable microlensing event because its source is photometrically bright and variable, which makes it possible to perform an asteroseismic analysis using ground-based data. We find that the source star is an oscillating red giant with a…
Initial phases of high-mass star formation: a multiwavelength study towards the extended green object G12.42+0.50
Tej, Anandmayee; Liu, Tie; Ishwara Chandra, C. H. +4 more
We present a multiwavelength study of the extended green object, G12.42+0.50, in this paper. The associated ionized, dust, and molecular components of this source are studied in detail employing various observations at near-, mid- and far-infrared, submillimetre, and radio wavelengths. Radio continuum emission mapped at 610 and 1390 MHz, using the…
The nature of the soft excess and spectral variability in the Seyfert 1 galaxy Zw 229.015
Welsh, W. F.; Gallo, L. C.; Waddell, S. G. H. +2 more
We have carried out a systematic analysis of the nearby (z = 0.0279) active galaxy Zw 229.015 using multi-epoch, multi-instrument, and deep pointed observations with XMM-Newton, Suzaku, Swift,and NuSTAR. Spectral and temporal variability are examined in detail on both the long (weeks-to-years) and short (hours) time-scales. A deep Suzaku observati…