Search Publications
Extragalactic number counts at 100 µm, free from cosmic variance
Ivison, R. J.; Roseboom, I. G.; van der Werf, P. P. +4 more
We use data from the Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre (DEBRIS) survey, taken at 100 µm with the Photoconductor Array Camera and Spectrometer instrument on board the Herschel Space Observatory, to make a cosmic variance independent measurement of the extragalactic number counts. These data consist of …
Optical and X-ray properties of CAL 83 - I. Quasi-periodic optical and supersoft variability
Udalski, A.; Charles, P. A.; Meintjes, P. J. +2 more
We have studied the long-term (∼ years) temporal variability of the prototype supersoft X-ray source (SSS) CAL 83 in the Large Magellanic Cloud, using data from the massive compact halo object (MACHO) and Optical Gravitational Lensing Experiment (OGLE) projects. The CAL 83 light curve exhibits dramatic brightness changes of ∼1 mag on time-scales o…
The orientation dependence of quasar spectral energy distributions
Brotherton, M. S.; Runnoe, Jessie C.; Shang, Z.
We investigate the orientation dependence of the spectral energy distributions in a sample of radio-loud quasars. Selected specifically to study orientation issues, the sample contains 52 sources with redshifts in the range 0.16 < z < 1.4 and measurements of radio core dominance, a radio orientation indicator. Measured properties include mon…
Mining unusual and rare stellar spectra from large spectroscopic survey data sets using the outlier-detection method
Liu, Jie; Kong, Xiao; Li, Yinbi +9 more
The large number of spectra obtained from sky surveys such as the Sloan Digital Sky Survey (SDSS) and the survey executed by the Large sky Area Multi-Object fibre Spectroscopic Telescope (LAMOST, also called GuoShouJing Telescope) provide us with opportunities to search for peculiar or even unknown types of spectra. In response to the limitations …
Evidence of rocky planetesimals orbiting two Hyades stars
Gänsicke, B. T.; Koester, D.; Farihi, J.
The Hyades is the nearest open cluster, relatively young and containing numerous A-type stars; its known age, distance, and metallicity make it an ideal site to study planetary systems around 2-3 M⊙ stars at an epoch similar to the late heavy bombardment. Hubble Space Telescope far-ultraviolet spectroscopy strongly suggests ongoing, ext…
A Herschel-ATLAS study of dusty spheroids: probing the minor-merger process in the local Universe
Clements, D. L.; Smith, M.; Cooray, A. +25 more
We use multiwavelength (0.12-500 µm) photometry from Herschel-ATLAS, WISE, UKIDSS, SDSS and GALEX to study 23 nearby spheroidal galaxies with prominent dust lanes (DLSGs). DLSGs are considered to be remnants of recent minor mergers, making them ideal laboratories for studying both the interstellar medium (ISM) of spheroids and minor-merger-d…
Timing and spectral analysis of the unusual X-ray transient XTE J0421+560/CI Camelopardalis
Bartlett, E. S.; Coe, M. J.; Uttley, P. +2 more
We present a detailed X-ray study of the 2003 XMM-Newton observation of the high-mass X-ray binary XTE J0421+560/CI Camelopardalis. The continuum of the X-ray spectrum is well described by a flat power law (Γ = 1.0 ± 0.2) with a large intrinsic absorbing column (NH = (4.4 ± 0.5) × 1023 cm-2). We have decomposed the…
The nature of the H2-emitting gas in the Crab nebula
Richardson, C. T.; Fabian, A. C.; Ferland, G. J. +4 more
Understanding how molecules and dust might have formed within a rapidly expanding young supernova remnant is important because of the obvious application to vigorous supernova activity at very high redshift. In previous papers, we have mapped the Crab nebula (the Crab) in a rotovibrational H2 emission line, and then measured the molecul…
Emission spectrum of ionized gas in the irregular galaxy Holmberg II
Moiseev, A. V.; Lozinskaya, T. A.; Egorov, O. V.
We studied the ionized gas spectra of star-forming regions in the Holmberg II galaxy using optical long-slit spectroscopic observations made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS). We estimated the oxygen, nitrogen, sulphur, neon and argon abundances in individual H II regions a…
Serendipitous detection of an overdensity of Herschel-SPIRE 250 µm sources south of MRC 1138-26
Berta, S.; Altieri, B.; Dannerbauer, H. +9 more
We report the serendipitous detection of a significant overdensity of Herschel-Spectral and Photometric Imaging Receiver 250 µm sources in the vicinity of MRC 1138-26. We use an adaptive kernel density estimate to quantify the significance, including a comparison with other fields. The overdensity has a size of ∼3.5-4 arcmin and stands out a…