Search Publications
CAPOS: The bulge Cluster APOgee Survey. III. Spectroscopic tomography of Tonantzintla 2
Cohen, Roger E.; Beers, Timothy C.; Minniti, Dante +10 more
We performed the first detailed spectral analysis of red giant members of the relatively high-metallicity globular cluster (GC) Tononzintla 2 (Ton 2) using high-resolution near-infrared spectra collected with the Apache Point Observatory Galactic Evolution Experiment II survey (APOGEE-2), obtained as part of the bulge Cluster APOgee Survey. We inv…
Differences in star formation activity between tidally triggered and isolated bars: a case study of NGC 4303 and NGC 3627
Okamoto, Takashi; Pettitt, Alex R.; Iles, Elizabeth J.
Galactic bars are important drivers of galactic evolution, and yet how they impact the interstellar medium and correspondingly star formation, remains unclear. We present simulation results for two barred galaxies with different formation mechanisms, bars formed in isolation or via a tidal interaction, to consider the spatially and temporally vary…
A Roche lobe-filling hot subdwarf and white dwarf binary: possible detection of an ejected common envelope
Wang, Luqian; Han, Zhanwen; Chen, Xuefei +12 more
Binaries consisting of a hot subdwarf star and an accreting white dwarf (WD) are sources of gravitational wave radiation at low frequencies and possible progenitors of Type Ia supernovae if the WD mass is large enough. Here, we report the discovery of the third binary known of this kind: It consists of a hot subdwarf O (sdO) star and a WD with an …
A chemical map of the outbursting V883 Ori system: vertical and radial structures
Kastner, J. H.; Williams, J. P.; Cieza, L. +3 more
We present the first results of a pilot program to conduct an Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 (211-275 GHz) spectral line study of young stellar objects (YSOs) that are undergoing rapid accretion episodes, i.e. FU Ori objects (FUors). Here, we report on molecular emission line observations of the FUor system, V883 Ori. I…
Dynamical Friction in Globular Cluster-rich Ultra-diffuse Galaxies: The Case of NGC5846-UDG1
Danieli, Shany; Bar, Nitsan; Blum, Kfir
Ultra-diffuse galaxies that contain a large sample of globular clusters (GCs) offer an opportunity to test the predictions of galactic dynamics theory. NGC5846-UDG1 is an excellent example, with a high-quality sample of dozens of GC candidates. We show that the observed distribution of GCs in NGC5846-UDG1 is suggestive of mass segregation induced …
Is [Y/Mg] a Reliable Age Diagnostic for FGK Stars?
van Saders, Jennifer L.; Huber, Daniel; Claytor, Zachary R. +3 more
Current spectroscopic surveys are producing large catalogs of chemical abundances for stars of all types. The yttrium-to-magnesium ratio, [Y/Mg], has emerged as a candidate age indicator for solar twins in the local stellar neighborhood. However, it is unclear whether it is a viable age diagnostic for more diverse stellar types, so we investigate …
Searching for a Hypervelocity White Dwarf SN Ia Companion: A Proper-motion Survey of SN 1006
Lu, Jessica R.; Rest, Armin; Zenteno, Alfredo +7 more
Type Ia supernovae (SNe Ia) are securely understood to come from the thermonuclear explosion of a white dwarf as a result of binary interaction, but the nature of that binary interaction and the secondary object is uncertain. Recently, a double white dwarf model known as the dynamically driven double-degenerate double-detonation (D6) model has bec…
Resolved Gaia Triples
Tokovinin, Andrei
A sample of 392 low-mass hierarchical triple stellar systems within 100 pc resolved by Gaia as distinct sources is defined. Owing to the uniform selection, the sample is ideally suited to study unbiased statistics of wide triples. The median projected separations in their inner and outer pairs are 151 and 2569 au, respectively, and the median sepa…
Hard X-ray luminosity functions of cataclysmic variables: joint Swift/BAT and Gaia data
Doroshenko, Victor; Suleimanov, Valery F.; Werner, Klaus
Cataclysmic variables (CVs) are the most numerous population among the Galactic objects emitting in hard X-rays. Most probably, they are responsible for the extended hard X-ray emission of the Galactic ridge and the central Galactic regions. Here, we consider the sample of CVs detected in the all-sky hard X-ray Swift/BAT survey, which were also de…
The Intermediate-ionization Lines as Virial Broadening Estimators for Population A Quasars
Piconcelli, Enrico; D'Onofrio, Mauro; Martínez-Aldama, Mary Loli +10 more
The identification of a virial broadening estimator in the quasar UV rest frame suitable for black hole mass computation at high redshift has become an important issue. We compare the H I Balmer H β line width to the ones of two intermediate-ionization lines: the Al III λ1860 doublet and the C III] λ1909 line, over a wide interval of redshift and …