Search Publications
ASASSN-16oh: A Nova Outburst with No Mass Ejection—A New Type of Supersoft X-Ray Source in Old Populations
Kato, Mariko; Hachisu, Izumi; Saio, Hideyuki
ASASSN-16oh is a peculiar transient supersoft X-ray source without a mass-ejection signature in the field of the Small Magellanic Cloud. Maccarone et al. concluded that ASASSN-16oh is the first dwarf nova with supersoft X-ray that originated from an equatorial accretion belt on a white dwarf (WD). Hillman et al. proposed a thermonuclear runaway mo…
Ages of Dwarfs in the Solar Neighborhood: Considering C and O Enhancements
Wu, Yaqian; Chen, Yuqin; Bi, Shaolan +7 more
Precise stellar ages of stars are necessary to study the evolution of the Milky Way. The age determination is significantly affected by C and O abundances of stars due to their contribution to the overall metallicity and opacity. On the basis of C and O abundances derived from high-resolution observations, we determine the ages of 148 FGK-type dwa…
Ultradiffuse Galaxies in the Coma Cluster: Probing Their Origin and AGN Occupation Fraction
Bogdán, Ákos; Canning, Rebecca E. A.; Kovács, Orsolya E.
Ultradiffuse galaxies (UDGs) exhibit low surface brightness, but their optical extent is comparable to that of Milky Way-type galaxies. In this work, we utilize Chandra X-ray observations of 404 UDGs in the Coma cluster and address two crucial goals. First, we constrain the formation scenario of UDGs by probing the X-ray emission originating from …
A Framework for Relative Biosignature Yields from Future Direct Imaging Missions
Tuchow, Noah W.; Wright, Jason T.
Future exoplanet direct imaging missions, such as HabEx and LUVOIR, will select target stars to maximize the number of Earth-like exoplanets that can have their atmospheric compositions characterized. Because one of these missions' aims is to detect biosignatures, they should also consider the expected biosignature yield of planets around these st…
Predicted Masses of Galactic Cepheids in the Gaia Data Release 2
Marconi, Marcella; Molinaro, Roberto; Ripepi, Vincenzo +4 more
On the basis of recently computed nonlinear convective pulsation models of Galactic Cepheids, spanning wide ranges of input stellar parameters, we derive theoretical mass-dependent Period-Wesenheit relations in the Gaia bands, namely, G, GBP, and GBR, that are found to be almost independent of the assumed efficiency of supera…
Magnetic Energy Balance in the Quiet Sun on Supergranular Spatial and Temporal Scales
Consolini, Giuseppe; Berrilli, Francesco; Del Moro, Dario +1 more
Small-scale magnetic fields are ubiquitous in the quiet solar photosphere and may store and transfer huge amounts of energy to the upper atmospheric layers. For this reason, it is fundamental to constrain the energetics of the quiet Sun. By taking advantage of a 24 hr long magnetogram time series acquired by the Hinode mission without interruption…
A Comprehensive Study of Hα Emitters at z ∼ 0.62 in the DAWN Survey: The Need for Deep and Wide Regions
Finkelstein, Steven L.; Mobasher, Bahram; Zheng, Zhen-Ya +19 more
We present new estimates of the luminosity function (LF) and star formation rate density (SFRD) for an Hα-selected sample at z ∼ 0.62 from the Deep And Wide Narrow-band (DAWN) survey. Our results are based on a new Hα sample in the extended COSMOS region (compared to Coughlin et al.) with the inclusion of flanking fields, resulting in a total area…
Imagery and UV Spectroscopy of the LMC Supernova Remnant N103B Using HST
Blair, William P.; Raymond, John C.; Pirzkal, Norbert +6 more
We present Hubble Space Telescope (HST)/Wide Field Camera 3 multiband imagery of N103B, which is the remnant of a SN Ia in the Large Magellanic Cloud, as well as HST/Cosmic Origins Spectrograph (COS) ultraviolet spectroscopy of the brightest radiatively shocked region. The images show a wide range of morphology and relative emission-line intensiti…
LAMOST J040643.69+542347.8: The Fastest Rotator in the Galaxy
Li, Guang-Wei
Rotation and binary interaction play important roles in understanding the nature of massive stars (≳8M⊙). Some interesting transients, such as the long-duration gamma-ray bursts, are thought to be originated from fast-rotating massive stars. Because the strong stellar wind can effectively spin down a metal-rich massive star with fast ro…
Gamma-Ray Emission Revealed at the Western Edge of SNR G344.7-0.1
Ajello, M.; Marchesi, S.; Eagle, J. +2 more
We report on the investigation of a very high energy (VHE), Galactic γ-ray source recently discovered at >50 GeV using the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope (Fermi). This object, 2FHL J1703.4-4145, displays a very hard >50 GeV spectrum with a photon index Γγ ∼ 1.2 in the 2FHL catalog and, as s…