Search Publications
Three small transiting planets around the M-dwarf host star LP 358-499
Poppenhaeger, K.; Wells, R.; Watson, C. A.
We report on the detection of three transiting small planets around the low-mass star LP 358-499 (K2-133), using photometric data from the Kepler-K2 mission. Using multiband photometry, we determine the host star to be an early M dwarf with an age likely older than a gigayear. The three detected planets K2-133 b, c and d have orbital periods of ca…
K2 spots rotation in the helium star HD144941
Ramsay, Gavin; Jeffery, C. Simon
HD144941 is an evolved early-type metal-poor low-mass star with a hydrogen-poor surface. It is frequently associated with other intermediate helium-rich subdwarfs and extreme helium stars. Previous photometric studies have failed to detect any variability. New observations with the K2 mission show complex but periodic variations with a full amplit…
A Hubble Space Telescope survey for novae in M87 - III. Are novae good standard candles 15 d after maximum brightness?
Welch, D. L.; Lauer, Tod R.; Mikołajewska, Joanna +13 more
Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called maximum-magnitude rate of decline (MMRD) relat…
XMM-Newton study of the supersoft symbiotic system Draco C1
Sasaki, Manami; Saeedi, Sara; Ducci, Lorenzo
We present the results of the analysis of thirty-one XMM-Newton observations of the symbiotic star Draco C1 located in the Draco dwarf spheroidal galaxy. This object had been identified as a supersoft source based on ROSAT data. We analysed X-ray, ultraviolet (UV) and optical data taken with XMM-Newton in order to obtain the physical parameters an…
Multiwavelength follow-up observations of the tidal disruption event candidate 2XMMi J184725.1-631724
Strader, Jay; Lin, Dacheng; Grupe, Dirk +5 more
The ultrasoft X-ray flare 2XMMi J184725.1-631724 was serendipitously detected in two XMM-Newton observations in 2006 and 2007, with a peak luminosity of 6 × 1043 erg s-1. It was suggested to be a tidal disruption event (TDE) because its position is consistent with the centre of an inactive galaxy. It is the only known X-ray T…
CHANG-ES - XI. Circular polarization in the cores of nearby galaxies
Saikia, D. J.; Wang, Q. Daniel; Wiegert, Theresa +18 more
We detect five galaxies in the Continuum Halos in Nearby Galaxies - an EVLA Survey (CHANG-ES) sample that show circular polarization (CP) at L band in our high-resolution data sets. Two of the galaxies (NGC 4388 and NGC 4845) show strong Stokes V/I ≡ mC ∼ 2 per cent, two (NGC 660 and NGC 3628) have values of mC ∼ 0.3 per cent…
The infrared luminosity function of AKARI 90 µm galaxies in the local Universe
Goto, Tomotsugu; Kilerci Eser, Ece
Local infrared (IR) luminosity functions (LFs) are necessary benchmarks for high-redshift IR galaxy evolution studies. Any accurate IR LF evolution studies require accordingly accurate local IR LFs. We present IR galaxy LFs at redshifts of z ≤ 0.3 from AKARI space telescope, which performed an all-sky survey in six IR bands (9, 18, 65, 90, 140, an…
Morphologies of mid-IR variability-selected AGN host galaxies
Fazio, Giovanni G.; Ashby, Matthew L. N.; Willner, S. P. +2 more
We use multi-epoch 3.6 and 4.5 µm data from the Spitzer Extended Deep Survey (SEDS) to probe the AGN population among galaxies to redshifts ∼3 via their mid-IR variability. About 1 per cent of all galaxies in our survey contain varying nuclei, 80 per cent of which are likely to be AGN. Twenty-three per cent of mid-IR variables are also X-ray…
Swift UVOT grism observations of nearby Type Ia supernovae - I. Observations and data reduction
Filippenko, A. V.; Foley, R. J.; Kuin, N. P. M. +1 more
Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) are useful tools for understanding progenitor systems and explosion physics. In particular, UV spectra of SNe Ia, which probe the outermost layers, are strongly affected by the progenitor metallicity. In this work, we present 120 Neil Gehrels Swift Observatory UV spectra of 39 nearby SNe…
Ring-type structures in the Planck map of the CMB
An, Daniel; Meissner, Krzysztof A.; Nurowski, Paweł
We present the results of the quest for ring-type structures on the maps observed by the Planck satellite. The results show that the vicinity of one radius (γ = 0.14 rad) of the rings is distinguished. Twisting the circles into deformed ellipses gives a pronounced drop of significance with the increase of twisting; however, this behaviour is also …