Search Publications
Exploring the Mass-loss Histories of the Red Supergiants
Humphreys, Roberta M.; Jones, Terry J.; Gordon, Michael S. +1 more
We report mid- to far-infrared imaging and photometry from 7 to 37 µm with SOFIA/FORCAST and 2 µm adaptive optics imaging with LBTI/LMIRCam of a large sample of red supergiants (RSGs) in four Galactic clusters: RSGC1, RSGC2 = Stephenson 2, RSGC3, and NGC 7419. The RSGs in these clusters cover their expected range in luminosity and init…
The PAU Survey: Photometric redshifts using transfer learning from simulations
Carretero, J.; Castander, F. J.; Gaztanaga, E. +15 more
In this paper, we introduce the DEEPZ deep learning photometric redshift (photo-z) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. DEEPZ reduces the σ68 scatter statistic by 50 per cent at iAB = 22.5 compared to existing algorithms. This improvement is achieved through various method…
Models of the Mass-ejection Histories of Pre-planetary Nebulae. IV. Magnetized Winds and the Origins of Jets, Bullets, and FLIERs
Frank, Adam; Balick, Bruce; Liu, Baowei
This paper explores the influences and consequences of toroidal magnetic fields in shaping the visible lobes of pre-planetary nebulae (prePNe). To probe these influences we start with the steady, diverging, and field-free wind model of our previous papers and add weak to moderate toroidal fields to the winds in order to generate arrays of outcomes…
A multiplicity study of transiting exoplanet host stars. I. High-contrast imaging with VLT/SPHERE
Ginski, C.; Maxted, P. F. L.; Southworth, J. +3 more
Context. Many main-sequence stars are part of multiple systems. The effect of stellar multiplicity on planet formation and migration, however, is poorly understood.
Aims: We study the multiplicity of stars hosting known transiting extra-solar planets to test competing theories on the formation mechanisms of hot Jupiters.
Methods: We obse…
Self-consistent Analysis of Stellar Clusters: An Application to HST Data of the Halo Globular Cluster NGC 6752
Nardiello, D.; Barbuy, B.; Pérez-Villegas, A. +3 more
The Bayesian isochrone fitting using the Markov chain Monte Carlo algorithm is applied, to derive the probability distribution of the parameters age, metallicity, reddening, and absolute distance modulus. We introduce the SIRIUS code by means of simulated color-magnitude diagrams (CMDs), including the analysis of multiple stellar populations (MPs)…
Stellar Metallicities from SkyMapper Photometry I: A Study of the Tucana II Ultra-faint Dwarf Galaxy
Jerjen, Helmut; Frebel, Anna; Chiti, Anirudh +2 more
We present a study of the ultra-faint Milky Way dwarf satellite galaxy Tucana II using deep photometry from the 1.3 m SkyMapper telescope at Siding Spring Observatory, Australia. The SkyMapper filter set contains a metallicity-sensitive intermediate-band V filter covering the prominent Ca II K feature at 3933.7 Å. When combined with photometry fro…
Orbital Evidences for Dark-matter-free Milky Way Dwarf Spheroidal Galaxies
Hammer, Francois; Babusiaux, Carine; Bonifacio, Piercarlo +4 more
The nature of Milky Way dwarf spheroidals (MW dSphs) has been questioned, in particular whether they are dominated by dark matter (DM). Here we investigate an alternative scenario, for which tidal shocks are exerted by the MW to DM-free dSphs after a first infall of their gas-rich progenitors, and for which theoretical calculations have been verif…
New and improved rotational periods of magnetic CP stars from ASAS-3, KELT, and MASCARA data
Paunzen, Ernst; Hümmerich, Stefan; Bernhard, Klaus
Magnetic chemically peculiar (mCP) stars allow the investigation of such diverse phenomena as atomic diffusion, magnetic fields, and stellar rotation. The aim of the present investigation is to enhance our knowledge of the rotational properties of mCP stars by increasing the sample of objects with accurately determined rotational periods. To this …
Gravitational-wave Radiation of Double Degenerates with Extremely Low-mass White Dwarf Companions
Han, Zhanwen; Chen, Xuefei; Li, Zhenwei +3 more
Double degenerate (DD) systems are supposed to be significant gravitational-wave (GW) sources for future space-based GW detectors, e.g., the Laser Interferometer Space Antenna (LISA). Recently, one type of DD system with extremely low-mass WD (ELM WD; ≲ 0.30 M⊙) companions was found in the ELM Survey. These companions have very short or…
Evolution of the Alfvén Mach number associated with a coronal mass ejection shock
Gallagher, Peter T.; Carley, Eoin P.; Maguire, Ciara A. +1 more
The Sun regularly produces large-scale eruptive events, such as coronal mass ejections (CMEs) that can drive shock waves through the solar corona. Such shocks can result in electron acceleration and subsequent radio emission in the form of a type II radio burst. However, the early-phase evolution of shock properties and its relationship to type II…