Search Publications
A search for young exoplanets in Sectors 1-5 of the TESS full-frame images
Armstrong, David J.; Pollacco, Don; Battley, Matthew P.
Young (<1 Gyr) exoplanets represent a critically important area of exoplanet research, as they offer the opportunity to learn about the formation and early dynamic history of exoplanetary systems. However, finding young exoplanets is significantly complicated by the fast rotation and complex activity of their young host stars, which are often n…
Optical spectra of FO Aquarii during low and high accretion rates
Garnavich, P. M.; Marsh, T. R.; Breton, R. P. +7 more
Between 2016 May and 2018 September, the intermediate polar (IP) FO Aquarii exhibited two distinct low states and one failed low state. We present optical spectroscopy of FO Aquarii throughout this period, making this the first detailed study of an accretion disc during a low state in any IP. Analysis of these data confirm that the low states are …
High-resolution spectroscopy of red giants and 'yellow stragglers' in the southern open cluster NGC 2539
Pereira, C. B.; Holanda, N.; Drake, N. A. +1 more
We present a detailed high-resolution spectroscopic analysis of 12 red giant stars, in single and binaries or multiples systems, classified as members of the intermediate-age (631 Myr) open cluster NGC 2539. We used FEROS echelle spectra and the standard LTE analysis to derive the atmospheric parameters for the stars and the abundance ratios of li…
Towards studying hierarchical assembly in real time: a Milky Way progenitor galaxy at z = 2.36 under the microscope
Johnson, Benjamin D.; Bouwens, Rychard; Weisz, Daniel R. +4 more
We use Hubble Space Telescope (HST) imaging and near-infrared spectroscopy from Keck/Multi-Object Spectrometer For Infra-Red Exploration (MOSFIRE) to study the substructure around the progenitor of a Milky Way-mass galaxy in the Hubble Frontier Fields (HFF). Specifically, we study an $r_\mathrm{ e} = 40^{+70}_{-30}$ pc, $M_{\star } \sim 10^{8.2} \…
WR 72: a born-again planetary nebula with hydrogen-poor knots
Gvaramadze, V. V.; Gräfener, G.; Langer, N. +1 more
We report the discovery of a handful of optical hydrogen-poor (H-poor) knots in the central part of an extended infrared nebula centred on the [WO1] star WR 72, obtained by spectroscopic and imaging observations with the Southern African Large Telescope (SALT). Wide-field Infrared Survey Explorer (WISE) images of the nebula show that it is compose…
The PAU Survey: background light estimation with deep learning techniques
Carretero, J.; Castander, F. J.; García-Bellido, J. +17 more
In any imaging survey, measuring accurately the astronomical background light is crucial to obtain good photometry. This paper introduces BKGNET, a deep neural network to predict the background and its associated error. BKGNET has been developed for data from the Physics of the Accelerating Universe Survey (PAUS), an imaging survey using a 40 narr…
Variable stars in the Sh 2-170 H II region
Matsunaga, N.; Sharma, Saurabh; Sinha, Tirthendu +7 more
We present multi-epoch deep (∼20 mag) Ic-band photometric monitoring of the Sh 2-170 star-forming region to understand the variability properties of pre-main-sequence (PMS) stars. We report identification of 47 periodic and 24 non-periodic variable stars with periods and amplitudes ranging from ∼4 h to 18 d and from ∼0.1 to 2.0 mag, res…
The large amplitude X-ray variability in NGC 7589: possible evidence for accretion mode transition
Liu, Zhu; Yuan, Weimin; Liu, He-Yang +2 more
We report the discovery of large amplitude X-ray variability in the low-luminosity active galactic nucleus NGC 7589, and present possible observational evidence for accretion mode transition in this source. Long-term X-ray flux variations by a factor of more than 50 are found using X-ray data obtained by Swift/X-Ray Telescope and XMM-Newton over 1…
The impact of wind scalings on stellar growth and the baryon cycle in cosmological simulations
Kollmeier, Juna A.; Davé, Romeel; Weinberg, David H. +5 more
Many phenomenologically successful cosmological simulations employ kinetic winds to model galactic outflows. Yet systematic studies of how variations in kinetic wind scalings might alter observable galaxy properties are rare. Here we employ GADGET-3 simulations to study how the baryon cycle, stellar mass function, and other galaxy and CGM predicti…
AGN feedback in the FR II galaxy 3C 220.1
Jones, Christine; Nulsen, Paul E. J.; Forman, William R. +6 more
We present results from a deep (174 ks) Chandra observation of the FR-II radio galaxy 3C 220.1, the central brightest cluster galaxy (BCG) of a kT ∼ 4 keV cluster at z = 0.61. The temperature of the hot cluster medium drops from ∼5.9 to ∼3.9 keV at ∼35 kpc radius, while the temperature at smaller radii may be substantially lower. The central activ…