Search Publications
The frequency and mass-ratio distribution of binaries in clusters - I. Description of the method and application to M67
Albrow, Michael D.; Ulusele, Isaac H.
We present a new method for probabilistic generative modelling of stellar colour-magnitude diagrams (CMDs) to infer the frequency of binary stars and their mass-ratio distribution. The method invokes a mixture model to account for overlapping populations of single stars, binaries, and outliers in the CMD. We apply the model to Gaia observations of…
Evolution of the critical torus instability height and coronal mass ejection likelihood in solar active regions
O'Kane, Jennifer; James, Alexander W.; Williams, David R.
Aims: Working towards improved space weather predictions, we aim to quantify how the critical height at which the torus instability drives coronal mass ejections (CMEs) varies over time in a sample of solar active regions.
Methods: We model the coronal magnetic fields of 42 active regions and quantify the critical height at their central…
Is the Subsurface Meridional Flow Zero at the Equator?
Komm, R.
We study the subsurface meridional flow and its divergence from the surface to a depth of about 16 Mm at the equator and its variation with the solar cycle derived with ring-diagram analysis applied to Michelson Doppler Imager (MDI) Dynamics Program, Global Oscillation Network Group (GONG), and Helioseismic and Magnetic Imager (HMI) Dopplergrams. …
LoVoCCS. I. Survey Introduction, Data Processing Pipeline, and Early Science Results
Cooper, M. C.; Donahue, Megan; Miyatake, Hironao +19 more
We present the Local Volume Complete Cluster Survey (LoVoCCS; we pronounce it as "low-vox" or "law-vox," with stress on the second syllable), an NSF's National Optical-Infrared Astronomy Research Laboratory survey program that uses the Dark Energy Camera to map the dark matter distribution and galaxy population in 107 nearby (0.03 < z < 0.12…
The Twisted Magnetic Field of the Protobinary L483
Pattle, Kate; Coudé, Simon; Bourke, Tyler L. +16 more
We present H-band (1.65 µm) and SOFIA HAWC+ 154 µm polarization observations of the low-mass core L483. Our H-band observations reveal a magnetic field that is overwhelmingly in the E-W direction, which is approximately parallel to the bipolar outflow that is observed in scattered IR light and in single-dish 12CO observation…
Inconspicuous Solar Polar Coronal X-Ray Jets as the Source of Conspicuous Hinode/EUV Imaging Spectrometer Doppler Outflows
Harra, Louise K.; Panesar, Navdeep K.; Moore, Ronald L. +3 more
We examine in greater detail five events previously identified as being sources of strong transient coronal outflows in a solar polar region in Hinode/Extreme Ultraviolet (EUV) Imaging Spectrometer (EIS) Doppler data. Although relatively compact or faint and inconspicuous in Hinode/X-ray Telescope (XRT) soft-X-ray (SXR) images and in Solar Dynamic…
Exploring the Link between the X-Ray Power Spectra and Energy Spectra of Active Galactic Nuclei
Jin, Chichuan; Yuan, Weimin; Yang, Haonan
Active galactic nuclei (AGN) are generally considered the scaled-up counterparts of X-ray binaries (XRBs). It is known that the power spectral density (PSD) of the X-ray emission of XRBs shows significant evolution with spectral state. It is not clear whether AGN follow a similar evolutionary trend, however, though their X-ray emission and the PSD…
Searching for Variable Stars in the Open Cluster NGC 2355 and Its Surrounding Region
Hu, Qingshun; Zhang, Yu; Qin, Mingfeng +4 more
We have investigated the variable stars in the field surrounding NGC 2355 based on the time-series photometric observation data. More than 3000 CCD frames were obtained in the V band spread over 13 nights with the Nanshan One-meter Wide-field Telescope. We have detected 88 variable stars, containing 72 new variable stars and 16 known variable star…
Spectroscopic confirmation of a gravitationally lensed Lyman-break galaxy at z[C II] = 6.827 using NOEMA
Schaerer, D.; Zitrin, A.; van der Werf, P. +8 more
We present the spectroscopic confirmation of the brightest known gravitationally lensed Lyman-break galaxy in the Epoch of Reionization (EoR), A1703-zD1, through the detection of [C II] 158 $\mu$m at a redshift of z = 6.8269 ± 0.0004. This source was selected behind the strong lensing cluster Abell 1703, with an intrinsic luminosity and a very blu…
Revising Properties of Planet-Host Binary Systems. I. Methods and Pilot Study
Kraus, Adam L.; Mann, Andrew W.; Sullivan, Kendall
To fully leverage the statistical strength of the large number of planets found by projects such as the Kepler survey, the properties of planets and their host stars must be measured as accurately as possible. One key population for planet demographic studies is circumstellar planets in close binaries (ρ < 50 au), where the complex dynamical en…