Search Publications
A WFC3 study of globular clusters in NGC 4150: an early-type minor merger
Mutchler, Max; Calzetti, Daniela; Whitmore, Bradley C. +8 more
We combine near-ultraviolet (NUV; 2250 Å) and optical (U, B, V, I) imaging from the Wide Field Camera 3 (WFC3), on-board the Hubble Space Telescope (HST), to study the globular cluster (GC) population in NGC 4150, a sub-L* (MB∼-18.48 mag) early-type minor-merger remnant in the Coma I cloud. We use broad-band NUV-optical photometry from …
Suzaku X-ray spectral study of the Compton-thick Seyfert galaxy NGC 5135
Risaliti, Guido; Singh, Veeresh; Braito, Valentina +1 more
We present the 0.5-50 keV Suzaku broad-band X-ray spectral study of the Compton-thick active galactic nucleus (AGN) in NGC 5135. The Suzaku observation provides the first detection of NGC 5135 above 10 keV that allowed us, for the first time, to estimate the absorbing column density, the intrinsic X-ray luminosity, the strength of the reflection c…
Precision astrometry of the exoplanet host candidate GD 66
Farihi, J.; Nelan, E. P.; Nordhaus, J. +4 more
The potential existence of a giant planet orbiting within a few au of a stellar remnant has profound implications for both the survival and possible regeneration of planets during post-main-sequence stellar evolution. This paper reports Hubble Space Telescope Fine Guidance Sensor and US Naval Observatory relative astrometry of GD 66, a white dwarf…
Herschel SPIRE observations of the TWA brown dwarf disc 2MASSW J1207334-393254
Lodato, G.; Riaz, B.; Stamatellos, D. +1 more
We present Herschel/SPIRE observations for the 2MASS 1207334-393254 (2M1207) system. Based on radiative transfer modelling of near-infrared to submillimetre data, we estimate a disc mass of 3 ± 2 MJup and an outer disc radius of 50-100 au for the 2M1207A disc. The relative disc mass for 2M1207A is similar to the T Tauri star TW Hya, whi…
X-ray observations of INTEGRAL discovered cataclysmic variable IGR J17195-4100
Singh, K. P.; Girish, V.
We present the analysis of archival X-ray data obtained with the XMM-Newton and Suzaku for a new intermediate polar identified as a counterpart of an INTEGRAL discovered γ-ray source, IGR J17195-4100. We report a new period of 1053.7 ± 12.2 s in X-rays. A new binary orbital period of 3.52-0.80+1.43 h is strongly indicated in the power spectrum of …
A new method to detect solar-like oscillations at very low S/N using statistical significance testing
Chaplin, William J.; Kjeldsen, Hans; Lund, Mikkel N.
We introduce a new method to detect solar-like oscillations in frequency power spectra of stellar observations, under conditions of very low signal-to-noise ratio. The Moving-Windowed-Power-Search (MWPS) searches the power spectrum for signatures of excess power, over and above slowly varying (in frequency) background contributions from stellar gr…
Two-dimensional Monte Carlo radiative transfer modelling of the disc-shaped secondary of Epsilon Aurigae
Parthasarathy, M.; Muthumariappan, C.
We present two-dimensional Monte Carlo radiative transfer models for the disc of the eclipsing binary Epsilon Aurigae by fitting its spectral energy distribution (SED) from optical to far-infrared (IR) wavelengths. We also report new observations of Epsilon Aurigae made by AKARI in its five mid- and far-IR photometric bands and which were used to …
Intervening broad-line region clouds' effects on the optical/ultraviolet spectrum
Ferland, Gary J.; Du, Pu; Hu, Chen +2 more
Recent X-ray observations of Mrk 766 suggest that broad emission-line region clouds cross our line of sight and produce variable X-ray absorption. Here we investigate what optical/ultraviolet (UV) spectroscopic features would be produced by such 'intervening broad-line region (BLR) clouds' (IBC) crossing our line of sight to the accretion disc, th…
Characterizing the nature of fossil groups with XMM
Paolillo, M.; La Barbera, F.; De Filippis, E. +1 more
We present an X-ray follow-up, based on XMM plus Chandra, of six fossil group (FG) candidates identified in our previous work using Sloan Digital Sky Survey (SDSS) and ROSAT All-Sky Survey (RASS) data. Four candidates (out of six) exhibit extended X-ray emission, confirming them as true FGs. For the other two groups, the RASS emission has its orig…
A deep X-ray observation of the supernova remnant G304.6+0.1 (Kes 17) using Suzaku
Sezer, A.; Gök, F.
In this paper, we present the analysis of a deep (99.6 ks) observation of G304.6+0.1 with the X-ray Imaging Spectrometer on board the Suzaku satellite. The X-ray spectral data are well fitted with a plasma model consisting of a thermal component, in collisional ionization equilibrium, and a non-thermal component. The thermal emission is well fitte…