Search Publications
Phase-space Correlation in Stellar Streams of the Milky Way Halo: The Clash of Kshir and GD-1
Malhan, Khyati; Ibata, Rodrigo A.; Martin, Nicolas F. +3 more
We report the discovery of a 70^\circ long stellar stream in the Milky Way halo, which criss-crosses the well known “GD-1” stream. We show that this new stellar structure (“Kshir”) and GD-1 lie at similar distance, and are remarkably correlated in kinematics. We propose several explanations for the nature of this new structure and its possible ass…
Helium enrichment in intermediate-age Magellanic Clouds clusters: towards an ubiquity of multiple stellar populations?
Martocchia, S.; Salaris, M.; Bastian, N. +1 more
Intermediate-age star clusters in the Magellanic Clouds harbour signatures of the multiple stellar populations long thought to be restricted to old globular clusters. We compare synthetic horizontal branch models with Hubble Space Telescope photometry of clusters in the Magellanic Clouds, with age between ∼2 and ∼10 Gyr, namely NGC 121, Lindsay 1,…
The B-Star Exoplanet Abundance Study: a co-moving 16-25 MJup companion to the young binary system HIP 79098
Reffert, Sabine; Langlois, Maud; Delorme, Philippe +13 more
Wide low-mass substellar companions are known to be very rare among low-mass stars, but appear to become increasingly common with increasing stellar mass. However, B-type stars, which are the most massive stars within 150 pc of the Sun, have not yet been examined to the same extent as AFGKM-type stars in that regard. In order to address this issue…
High-precision Dynamical Masses of Pre-main-sequence Stars with ALMA and Gaia
Sheehan, Patrick D.; Tobin, John J.; Wu, Ya-Lin +1 more
The Keplerian rotation in protoplanetary disks can be used to robustly measure stellar masses at very high precision if the source distance is known. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of spatially and spectrally resolved 12CO (2-1) emission toward the disks around 2MASS J16262774-2527247 (the te…
Dust emission profiles of DustPedia galaxies
Bianchi, S.; Fritz, J.; Madden, S. C. +19 more
Most radiative transfer models assume that dust in spiral galaxies is distributed exponentially. In this paper our goal is to verify this assumption by analysing the two-dimensional large-scale distribution of dust in galaxies from the DustPedia sample. For this purpose, we have made use of Herschel imaging in five bands, from 100 to 500 µm,…
Using [C II] 158 µm Emission from Isolated ISM Phases as a Star Formation Rate Indicator
Hunt, Leslie K.; Calzetti, Daniela; Bolatto, Alberto D. +17 more
The brightest observed emission line in many star-forming galaxies is the [{{C}} {{II}}] 158 µm line, making it detectable up to z ∼ 7. In order to better understand and quantify the [{{C}} {{II}}] emission as a tracer of star formation, the theoretical ratio between the [{{N}} {{II}}] 205 µm emission and the [{{C}} {{II}}] 158 µ…
New Nearby Hypervelocity Stars and Their Spatial Distribution from Gaia DR2
Shi, Jianrong; Chen, Yuqin; Ma, Jun +5 more
Based on about 4500 large tangential velocity (V tan > 0.75V esc) with high-precision proper motions and 5σ parallaxes in Gaia data release 2 (DR2) 5D information derived from parallax and proper motion, we identify more than 600 high-velocity stars with a 50% unbound probability. Of these, 28 nearby (less than 6 kpc) late…
A new study of the variable star population in the Hercules globular cluster (M13; NGC 6205)
Arellano Ferro, A.; Calderón, J. H.; Lázaro, C. +4 more
We present the results from VI CCD time-series photometry of the globular cluster M13 (NGC 6205). From the Fourier decomposition of the light curves of RRab and RRc stars we found an average metallicity of [Fe/H]zw = -1.58 ± 0.09. The distance to the cluster was estimated as 7.1 ± 0.1 kpc from independent methods related to the variable star famil…
Rediscovery of the Sixth Star Cluster in the Fornax Dwarf Spheroidal Galaxy
Bacon, D.; Bechtol, K.; Wang, M. Y. +60 more
Since first noticed by Shapley in 1939, a faint object coincident with the Fornax dwarf spheroidal has long been discussed as a possible sixth globular cluster (GC) system. However, debate has continued over whether this overdensity is a statistical artifact or a blended galaxy group. In this Letter we demonstrate, using deep DECam imaging data, t…
60Fe in core-collapse supernovae and prospects for X-ray and gamma-ray detection in supernova remnants
Safi-Harb, Samar; Fryer, Chris L.; Mumpower, Matthew R. +6 more
We investigate 60Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20, and 25 M⊙ stars at solar metallicity. We find that the 60Fe yield is a monotonic increasing function of the uncertain 59Fe(n, γ)60Fe cross-section and that a fa…