Search Publications
Magnetic activity based on LAMOST medium-resolution spectra and the Kepler survey
Shi, Jianrong; Gao, Qi; Han, Xianming L. +6 more
Stellar magnetic activity is an interesting phenomenon in late-type stars. We use the medium-resolution spectroscopic observations of 406 069 late-type stars from LAMOST to explore their properties. We perform a statistical analysis on the magnetic activity of the stars and their associated physical parameters. Our samples are cross-matched with o…
A Gravitational Redshift Measurement of the White Dwarf Mass-Radius Relation
Cheng, Sihao; Zakamska, Nadia L.; Chandra, Vedant +1 more
The mass-radius relation of white dwarfs is largely determined by the equation of state of degenerate electrons, which causes the stellar radius to decrease as mass increases. Here we observationally measure this relation using the gravitational redshift effect, a prediction of general relativity that depends on the ratio between stellar mass and …
ALMA Observations of Quasar Host Galaxies at z ≃ 4.8
Maiolino, Roberto; Trakhtenbrot, Benny; Netzer, Hagai +4 more
We present ALMA Band 7 data of the [C II] $\lambda 157.74\,\mu {\rm{m}}$ emission line and underlying far-IR (FIR) continuum for 12 luminous quasars at $z\simeq 4.8$ powered by fast-growing supermassive black holes (SMBHs). Our total sample consists of 18 quasars, 12 of which are presented here for the first time. The new sources consist of six He…
Spectral and atmospheric characterisation of a new benchmark brown dwarf HD 13724 B
Ségransan, D.; Delisle, J. -B.; Udry, S. +5 more
Context. HD 13724 is a nearby solar-type star at 43.48 ± 0.06 pc hosting a long-period low-mass brown dwarf detected with the CORALIE echelle spectrograph as part of the historical CORALIE radial-velocity search for extra-solar planets. The companion has a minimum mass of 26.77-2.2+4.4 MJup and an expected semi-maj…
Disk Illumination and Jet Variability of the Herbig Ae Star HD 163296 Using Multi-epoch HST/STIS Optical, Near-IR, and Radio Imagery and Spectroscopy
Fukagawa, Misato; Sitko, Michael L.; Grady, Carol A. +3 more
We present two new epochs of Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph coronagraphic imaging, along with multi-epoch optical, near-IR, and radio monitoring, of the HD 163296 system. We find that ansae features identified in earlier-epoch HST imagery are a fourth ring that resides at a semimajor axis distance of 3"25 (330 au…
The dependence of Type Ia Supernovae SALT2 light-curve parameters on host galaxy morphology
Pruzhinskaya, M. V.; Pauna, N.; Novinskaya, A. K. +1 more
Type Ia Supernovae (SNe Ia) are widely used to measure distances in the Universe. Despite the recent progress achieved in SN Ia standardization, the Hubble diagram still shows some remaining intrinsic dispersion. The remaining scatter in supernova luminosity could be due to the environmental effects that are accounted for as mass step correction i…
Properties of Solar Rossby Waves from Normal Mode Coupling and Characterizing Its Systematics
Mandal, Krishnendu; Hanasoge, Shravan
Rossby waves play an important role in mediating the angular momentum of rotating spherical fluids, creating weather on Earth and tuning exoplanet orbits in distant stellar systems. Their recent discovery in the solar convection zone provides an exciting opportunity to appreciate the detailed astrophysics of Rossby waves. Large-scale Rossby waves …
The GTC exoplanet transit spectroscopy survey. XI. Possible detection of Rayleigh scattering in the atmosphere of the Saturn-mass planet WASP-69b
Nortmann, L.; Palle, E.; Nowak, G. +2 more
Context. One of the main atmospheric features in exoplanet atmospheres, detectable both from ground- and space-based facilities, is Rayleigh scattering. In hydrogen-dominated planetary atmospheres, Rayleigh scattering causes the measured planetary radius to increase toward blue wavelengths in the optical range.
Aims: We aim to detect and impr…
Unlocking Galactic Wolf-Rayet stars with Gaia DR2 - II. Cluster and association membership
Parker, Richard J.; Crowther, Paul A.; Rate, Gemma
Galactic Wolf-Rayet (WR) star membership of star-forming regions can be used to constrain the formation environments of massive stars. Here, we utilize Gaia DR2 parallaxes and proper motions to reconsider WR star membership of clusters and associations in the Galactic disc, supplemented by recent near-infrared studies of young massive clusters. We…
The Cluster AgeS Experiment (CASE) - VIII. Age and distance of the Globular Cluster 47 Tuc from the analysis of two detached eclipsing binaries
Soszyński, I.; Udalski, A.; Szymański, M. K. +20 more
We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain M_p =…