Search Publications
Exploration of quasars with the Gaia mission
Wambsganss, Joachim; Proft, Svea
We analyze the opportunities in and limits to investigating quasars with the Gaia satellite by studying Gaia's low- and high-resolution quasar spectra, with consideration of their signal-to-noise ratios. Furthermore, we explore bright quasars from the Sloan Digital Sky Survey with broad emission lines (BELs) redshifted into the spectral range of G…
Dynamic SEP event probability forecasts
Kahler, S. W.; Ling, A.
The forecasting of solar energetic particle (SEP) event probabilities at Earth has been based primarily on the estimates of magnetic free energy in active regions and on the observations of peak fluxes and fluences of large (≥ M2) solar X-ray flares. These forecasts are typically issued for the next 24 h or with no definite expiration time, which …
Magnesium-rich Ejecta in the SNR G284.3-1.8 Around the High-mass Gamma-Ray Binary 1FGL J1018.6-5856
Pavlov, George G.; Kargaltsev, Oleg; Rangelov, Blagoy +1 more
We present results from two Chandra observations of the 16.6 day X-ray/γ-ray high-mass binary 1FGL J1018.6-5856 located at the center of the supernova remnant (SNR) G284.3-1.8. The binary spectra, separated by 0.25 in binary phase, are fit with an absorbed power-law model with {{Γ }}≈ 1.7-1.8 for both observations (the flux during the second obser…
Herschel-PACS observations of discs in the η Chamaeleontis association
Dent, W. R. F.; Kamp, I.; Montesinos, B. +6 more
Context. Protoplanetary discs are the birthplace of planets. Studying protoplanetary discs is the key to constraining theories of planet formation. By observing dust and gas in associations at different ages we can study the evolution of these discs, their clearing timescales, and their physical and geometrical properties.The stellar association η…
Two Populations of Old Star Clusters in the Spiral Galaxy M101 Based on HST/ACS Observations
Whitmore, Bradley C.; Chandar, Rupali; Simanton, Lesley A.
We present a new photometric catalog of 326 candidate globular clusters (GCs) in the nearby spiral galaxy M101, selected from B, V, and I Hubble Space Telescope Advanced Camera for Surveys images. The luminosity function (LF) of these clusters has an unusually large number of faint sources compared with GCLFs in many other spiral galaxies. Accordi…
Total mass of six quiescent prominences estimated from their multi-spectral observations
Heinzel, P.; Golub, L.; Schwartz, P. +4 more
Context. Total masses of six solar prominences were estimated using prominence multi-spectral observations (in EUV, X-rays, Hα, and Ca ii H). The observations were made during the observing campaign from April through June 2011.
Aims: The aim of the work was to apply a complex method for the prominence mass estimations that can be used later …
The Atacama Cosmology Telescope: The LABOCA/ACT Survey of Clusters at All Redshifts
Hilton, Matt; Sifón, Cristóbal; Bond, J. Richard +24 more
We present a multi-wavelength analysis of 11 Sunyaev-Zel’dovich effect (SZE)-selected galaxy clusters (10 with new data) from the Atacama Cosmology Telescope (ACT) southern survey. We have obtained new imaging from the Large APEX Bolometer Camera (345 GHz; LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope, the Australia Telescope Compa…
36 new, high-probability, damped Lyα absorbers at redshift 0.42 < z < 0.70
Turnshek, David A.; Rao, Sandhya M.; Monier, Eric M. +3 more
Quasar damped Lyα (DLA) absorption-line systems with redshifts z < 1.65 are used to trace neutral gas over approximately 70 per cent of the most recent history of the Universe. However, such systems fall in the UV and are rarely found in blind UV spectroscopic surveys. Therefore, it has been difficult to compile a moderate-sized sample of UV DL…
Detection of Yarkovsky acceleration in the context of precovery observations and the future Gaia catalogue
Desmars, J.
Context. The Yarkovsky effect is a weak non-gravitational force leading to a small variation of the semi-major axis of an asteroid. Using radar measurements and astrometric observations, it is possible to measure a drift in semi-major axis through orbit determination.
Aims: This paper aims to detect a reliable drift in semi-major axis of near…
Red giants in the outer halo of the elliptical galaxy NGC 5128/Centaurus A
Bird, Sarah A.; Harris, William E.; Flynn, Chris +1 more
We used VIMOS on VLT to perform V and I band imaging of the outermost halo of