Search Publications
Evidence of the γ-ray counterpart of nova FM Cir from Fermi-LAT
Takata, J.; Wang, H. H.; Lin, L. C. -C. +2 more
We report the results of an analysis of X-ray and γ-ray data from the nova FM Cir taken by Swift and Fermi-LAT. The γ-ray emission from FM Cir can be identified with a significance level of ~3σ within ~40 d after the nova eruption (2018 January 19) when we bin the light curve per day. The significance can exceed the 4σ confidence level if we accum…
Possible anticorrelations between pulsation amplitudes and the disc growth of Be stars in giant-outbursting Be X-ray binaries
Soria, Roberto; Ricker, George R.; Vanderspek, Roland +15 more
The mechanism of X-ray outbursts in Be X-ray binaries remains a mystery, and understanding their circumstellar discs is crucial for a solution of the mass-transfer problem. In particular, it is important to identify the Be star activities (e.g. pulsations) that cause mass ejection and, hence, disc formation. Therefore, we investigated the relation…
Revised ephemeris and orbital period derivative of the supersoft X-ray source CAL 87 based on 34 yr of observations
Saito, R. K.; Oliveira, A. S.; D'Amico, F. +4 more
In this study, we present an analysis of over 34 yr of observational data from CAL 87, an eclipsing supersoft X-ray source. The primary aim of our study, which combines previously analysed measurements as well as unexplored publicly available data sets, is to examine the orbital period evolution of CAL 87. After meticulously and consistently deter…
A study of Be stars in the time domain - I. Spectral data and polarimetry
Steele, Iain A.; Jermak, Helen E.; Castañón Esteban, Adrian
We present the first part of a spectroscopic and polarimetric study on a sample of 58 Be stars that have been measured since 1998. The aim of the study is to understand the time-scales of disc variability, formation, and dissipation as a function of the properties (mass, luminosity, and rotational velocity) of the underlying B star. In this paper,…
WEAVE First Light Observations: Origin and Dynamics of the Shock Front in Stephan's Quintet
Shimwell, T. W.; Monguió, M.; Hardcastle, M. J. +62 more
We present a detailed study of the large-scale shock front in Stephan's Quintet, a by-product of past and ongoing interactions. Using integral-field spectroscopy from the new William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE), recent 144 MHz observations from the LOFAR Two-metre Sky Survey, and archival data from the Very Large Arr…
A novel analysis of contamination in Lyman-break galaxy samples at z 6-8: spatial correlation with intermediate-redshift galaxies at z 1.3-2
Trenti, Michele; Leethochawalit, Nicha; Metha, Benjamin +1 more
Potential contamination from low/intermediate-redshift galaxies, such as objects with a prominent Balmer break, affects the photometric selection of high-redshift galaxies through identification of a Lyman break. Traditionally, contamination is estimated from spectroscopic follow-up and/or simulations. Here, we introduce a novel approach to estima…
A survey for variable young stars with small telescopes - IX. Evolution of spot properties on YSOs in IC 5070
Scholz, Aleks; Eislöffel, Jochen; Dvorak, Shawn +45 more
We present spot properties on 32 periodic young stellar objects in IC 5070. Long term, ~5 yr, light curves in the V, R, and I-bands are obtained through the HOYS (Hunting Outbursting Young Stars) citizen science project. These are dissected into 6 months long slices, with 3 months oversampling, to measure 234 sets of amplitudes in all filters. We …
The first low-mass eclipsing binary within the fully convective zone from TMTS
Kovalev, Mikhail; Zhu, Liying; Wang, Xiaofeng +17 more
We present a comprehensive photometric and spectroscopic analysis of the short-period (~5.32 h) and low-mass eclipsing binary TMTSJ0803 discovered by Tsinghua-Ma Huateng Telescope for Survey (TMTS). By fitting the light curves and radial velocity data with the Wilson-Devinney code, we find that the binary is composed of two late spotted active M d…
First deep X-ray observations of the Fermi-detected steep-spectrum source and radio-loud NLS1 galaxy 3C 286
Komossa, S.; Grupe, D.; Kraus, A. +1 more
A well-known calibrator source in radio astronomy, 3C 286 ($z=0.85$), is a compact steep-spectrum (CSS) radio source and spectroscopically classified as a narrow-line Seyfert 1 (NLS1) galaxy. It is also known for its damped Ly $\alpha$ system from an intervening galaxy at $z=0.692$ detected in both ultraviolet (UV) and radio spectra. In addition, …
Amplitude and phase changes in TESS photometry of five short period weak-lined T Tauri stars
Koen, C.
The statistical technique 'Complex Demodulation' (CDM) is used to track the amplitude and phase changes of periodicities in five naked T Tauri stars. The periodicities are most likely caused by dark spots on the stellar surfaces, which are rotated into and out of view. Two of the stars (CD-56 1438, CD-72 248) show two independent periodicities, pr…