Search Publications
Distillation of 56Fe in Ultramassive O-Ne White Dwarfs
Blouin, Simon; Caplan, Matthew E.; Freeman, Ian F.
When white dwarfs freeze, the plasma mixtures inside them undergo separation processes that can produce radical changes in the composition profile of the star. The abundance of neutron-rich elements, such as 22Ne or 56Fe, determines whether or not the first crystals are more or less dense than the surrounding fluid and thus w…
Physical Properties of 5000 Cool Large Magellanic Cloud Supergiants with Gaia XP Spectra: A Detailed Portrait of the Upper H-R Diagram Hints at Missing Supernova Progenitors
Dorn-Wallenstein, Trevor Z.; Levesque, Emily M.; Neugent, Kathryn F.
Characterizing the physical properties of cool supergiants allows us to probe the final stages of a massive star's evolution before it undergoes core collapse. Despite their importance, the fundamental properties of these stars- $\mathrm{log}{T}_{\mathrm{eff}}$ and $\mathrm{log}L/{L}_{\odot }$ -are only known for a limited number of objects. The t…
V445 Puppis: Dustier than a Thousand Novae
Evans, A.; Banerjee, D. P. K.; Starrfield, S. +4 more
V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this co…
A Census of Near-UV M-dwarf Flares Using Archival GALEX Data and the gPHOTON2 Pipeline
Shvartzvald, Yossi; Perdelwitz, Volker; Ben-Ami, Sagi +1 more
M-dwarfs are common stellar hosts of habitable-zone exoplanets. Near-UV (NUV) radiation can severely impact the atmospheric and surface conditions of such planets, making the characterization of NUV flaring activity a key aspect in determining habitability. We use archival data from the Galaxy Evolution Explorer (GALEX) and XMM-Newton telescopes t…
Hadronic Processes at Work in 5BZB J0630‑2406
Marchesi, Stefano; Fichet de Clairfontaine, Gaëtan; Buson, Sara +6 more
Recent observations are shedding light on the important role that active galactic nuclei play in the production of high-energy neutrinos. In this study, we focus on one object, 5BZB J0630‑2406, which is among the blazars recently proposed as associated with neutrino emission during the first 7 yr of IceCube observations. Modeling the quasi-simulta…
Massive Star Formation in the Tarantula Nebula
Hirschauer, Alec S.; Lebouteiller, Vianney; Lee, Min-Young +17 more
In this work, we present 299 candidate young stellar objects (YSOs) in 30 Doradus discovered using Spitzer and Herschel point-source catalogs, 276 of which are new. We study the parental giant molecular clouds in which these YSO candidates form using recently published Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 7 observations of
Role of Small-scale Impulsive Events in Heating the X-Ray Bright Points of the Quiet Sun
Del Zanna, Giulio; Bhardwaj, Anil; Mason, Helen E. +6 more
Small-scale impulsive events, known as nanoflares, are thought to be one of the prime candidates that can keep the solar corona hot at its multimillion-Kelvin temperature. Individual nanoflares are difficult to detect with the current generation of instruments; however, their presence can be inferred through indirect techniques such as Differentia…
A Broadband X-Ray Study of the Rabbit Pulsar Wind Nebula Powered by PSR J1418-6058
Woo, Jooyun; An, Hongjun; Mori, Kaya +4 more
We report on broadband X-ray properties of the Rabbit pulsar wind nebula (PWN) associated with the pulsar PSR J1418-6058 using archival Chandra and XMM-Newton data, as well as a new NuSTAR observation. NuSTAR data above 10 keV allowed us to detect the 110 ms spin period of the pulsar, characterize its hard X-ray pulse profile, and resolve hard X-r…
SDSS J134441.83+204408.3: A Highly Asynchronous Short-period Magnetic Cataclysmic Variable with a 56 MG Field Strength
Garnavich, Peter; Littlefield, Colin; Szkody, Paula +6 more
When the accreting white dwarf in a magnetic cataclysmic variable star (mCV) has a field strength in excess of 10 MG, it is expected to synchronize its rotational frequency to the binary orbit frequency, particularly at small binary separations, due to the steep radial dependence of the magnetic field. We report the discovery of an mCV (SDSS J1344…
The Fate of the Interstellar Medium in Early-type Galaxies. II. Observational Evidence for Morphological Quenching
Michałowski, M. J.; Hjorth, J.; Gall, C. +4 more
The mechanism by which galaxies stop forming stars and get rid of their interstellar medium (ISM) remains elusive. Here, we study a sample of more than 2000 elliptical galaxies in which dust emission has been detected. This is the largest sample of such galaxies ever analyzed. We infer the timescale for removal of dust in these galaxies and invest…