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Supervised Detection of Anomalous Light Curves in Massive Astronomical Catalogs
Kim, Dae-Won; Protopapas, Pavlos; Pichara, Karim +1 more
The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable obj…
The AIMSS Project II: dynamical-to-stellar mass ratios across the star cluster-galaxy divide
Forbes, Duncan A.; Romanowsky, Aaron J.; Brodie, Jean P. +5 more
The previously clear division between small galaxies and massive star clusters is now occupied by objects called ultra-compact dwarfs (UCDs) and compact ellipticals (cEs). Here we combine a sample of UCDs and cEs with velocity dispersions from the AIMSS project with literature data to explore their dynamical-to-stellar mass ratios. We confirm that…
Directional dependence of CMB parity asymmetry
Zhao, Wen
Parity violation in the cosmic microwave background (CMB) radiation has been confirmed by recent Planck observation. In this paper, we extend our previous work [P. Naselsky et al., Astrophys. J. 749, 31 (2012)] on the directional properties of CMB parity asymmetry by considering the Planck data of the CMB temperature anisotropy. We define six kind…
Rigorous treatment of barycentric stellar motion. Perspective and light-time effects in astrometric and radial velocity data
Lindegren, L.; Butkevich, A. G.
Context. High-precision astrometric and radial-velocity observations require accurate modelling of stellar motions in order to extrapolate measurements over long time intervals, and to detect deviations from uniform motion caused, for example, by unseen companions.
Aims: We aim to explore the simplest possible kinematic model of stellar motio…
The low or retrograde spin of the first extragalactic microquasar: implications for Blandford-Znajek powering of jets
Middleton, Matthew J.; Miller-Jones, James C. A.; Fender, Rob P.
Transitions to high mass accretion rates in black hole X-ray binaries are associated with the ejection of powerful, relativistically moving jets. The mechanism that powers such events is thought to be linked to tapping of the angular momentum (spin) of the black hole, the rate of accretion through the disc or some combination of the two. We can at…
Low-redshift quasars in the Sloan Digital Sky Survey Stripe 82. The host galaxies
Falomo, R.; Uslenghi, M.; Kotilainen, J. K. +2 more
We present a photometrical and morphological study of the properties of low-redshift (z < 0.5) quasars based on a large and homogeneous data set of objects derived from the Sloan Digital Sky Survey Data Release 7. This study over number by a factor of ∼5 any other previous study of quasi-stellar object (QSO) host galaxies at low redshift undert…
Ion densities and magnetic signatures of dust pickup at Enceladus
Dougherty, Michele K.; Saur, Joachim; Kriegel, Hendrik +5 more
Encedalus' plume of charged dust has been shown to strongly modify the plasma structures. Therefore, we analyze the magnetic signatures of dust to constrain the dust plume. For the first time, the mutual feedback between the nanograins and their plasma environment is investigated. Our model combines plasma simulations by means of the A.I.K.E.F. (A…
Herschel-SPIRE Fourier Transform Spectrometer Observations of Excited CO and [C I] in the Antennae (NGC 4038/39): Warm and Cold Molecular Gas
Wilson, Christine D.; De Looze, Ilse; Baes, Maarten +14 more
We present Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) observations of the Antennae (NGC 4038/39), a well-studied, nearby (22 Mpc), ongoing merger between two gas-rich spiral galaxies. The SPIRE-FTS is a low spatial ( FWHM ~ 19''-43'') and spectral (~1.2 GHz) resolution mapping spectrometer cover…
Swift J1357.2-0933: the faintest black hole?
Degenaar, N.; Wijnands, R.; Fender, R. P. +3 more
Swift J1357.2-0933 is a confirmed very faint black hole X-ray transient and has a short estimated orbital period of 2.8 h. We observed Swift J1357.2-0933 for ∼50 ks with XMM-Newton in 2013 July during its quiescent state. The source is clearly detected at a 0.5-10 keV unabsorbed flux of ∼3 × 10-15 erg cm-2 s-1. If …
Constraint on Light Dipole Dark Matter from Helioseismology
Lopes, Ilídio; Silk, Joseph; Kadota, Kenji
We investigate the effects of a magnetic dipole moment of asymmetric dark matter (DM) in the evolution of the Sun. The dipole interaction can lead to a sizable DM scattering cross section even for light DM, and asymmetric DM can lead to a large DM number density in the Sun. We find that solar model precision tests, using as diagnostic the sound sp…