Search Publications
The complex nature of the nuclear star cluster in FCC 277
Jordán, Andrés; van de Ven, Glenn; Infante, Leopoldo +6 more
Recent observations have shown that compact nuclear star clusters (NSCs) are present in up to 80 per cent of galaxies. However, detailed studies of their dynamical and chemical properties are confined mainly to spiral galaxy hosts, where they are more easily observed. In this paper, we present our study of the NSC in FCC 277, a nucleated elliptica…
On spectral line profiles in Type Ia supernova spectra
Foley, Ryan J.
We present a detailed analysis of spectral line profiles in Type Ia supernova (SN Ia) spectra. We focus on the feature at ∼3500-4000 Å, which is commonly thought to be caused by blueshifted absorption of Ca H&K. Unlike some other spectral features in SN Ia spectra, this feature often has two overlapping (blue and red) components. It is accepte…
The outer halo of the nearest giant elliptical: a VLT/VIMOS survey of the resolved stellar populations in Centaurus A to 85 kpc
Jablonka, P.; Crnojević, D.; Bernard, E. J. +4 more
We present the first survey of resolved stellar populations in the remote outer halo of our nearest giant elliptical (gE), Centaurus A (D = 3.8 Mpc). Using the VIsible Multi Object Spectrograph (VIMOS)/Very Large Telescope (VLT) optical camera, we obtained deep photometry for four fields along the major and minor axes at projected elliptical radii…
A bright ultraluminous X-ray source in NGC 5907
Sutton, Andrew D.; Roberts, Timothy P.; Goad, Michael R. +4 more
We present a multimission X-ray analysis of a bright (peak observed 0.3-10 keV luminosity of ∼6 × 1040 erg s-1), but relatively highly absorbed ultraluminous X-ray source (ULX) in the edge-on spiral galaxy NGC 5907. The ULX is spectrally hard in X-rays (Γ ∼ 1.2-1.7, when fitted with an absorbed power law), and has a previousl…
Milliarcsec-scale radio emission of ultraluminous X-ray sources: steady jet emission from an intermediate-mass black hole?
Farrell, S. A.; Mezcua, M.; Gladstone, J. C. +1 more
The origin of the high X-ray luminosities of most ultraluminous X-ray sources (ULXs) still remains poorly understood. Most of the scenarios proposed to explain their nature assume that ULXs are powered by accretion on to a black hole (BH). In this case, the detection of compact radio emission and the location of the ULXs in the Fundamental Plane (…
Phase-resolved ultraviolet spectroscopy of the magnetic Of?p star HD 191612
Bouret, J. -C.; Howarth, I. D.; Wade, G. A. +5 more
We present for the first time phase-resolved ultraviolet (UV) spectroscopy of an Of?p star, namely, HD 191612. The observations were acquired with the Space Telescope Imaging Spectrograph (STIS) onboard the Hubble Space Telescope (HST). We report the variability observed in the main photospheric and wind features and compare the results with previ…
Two rings but no fellowship: LoTr 1 and its relation to planetary nebulae possessing barium central stars
Boumis, P.; Pollacco, D.; Santander-García, M. +8 more
LoTr 1 is a planetary nebula thought to contain an intermediate-period binary central star system (that is, a system with an orbital period, P, between 100 and, say, 1500 d). The system shows the signature of a K type, rapidly rotating giant and most likely constitutes an accretion-induced post-mass-transfer system similar to other PNe, such as Lo…
Herschel-SPIRE Fourier transform spectroscopy of the nearby spiral galaxy IC 342
Magdis, G. E.; Rigopoulou, D.; Pellegrini, E. +9 more
We present observations of the nearby spiral galaxy IC 342 with the Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier transform spectrometer. The spectral range afforded by SPIRE, 196-671 µm, allows us to access a number of 12CO lines from J = 4-3 to J = 13-12 with the highest J transitions observed for the first …
The use and calibration of read-out streaks to increase the dynamic range of the Swift Ultraviolet/Optical Telescope
Carter, M.; Page, M. J.; Symeonidis, M. +12 more
The dynamic range of photon counting micro-channel-plate (MCP) intensified charged-coupled device (CCD) instruments such as the Swift Ultraviolet/Optical Telescope (UVOT) and the XMM-Newton Optical Monitor (XMM-OM) is limited at the bright end by coincidence loss, the superposition of multiple photons in the individual frames recorded by the CCD. …
The imprint of the crustal magnetic field on the thermal spectra and pulse profiles of isolated neutron stars
Rea, Nanda; Viganò, Daniele; Perna, Rosalba +1 more
Isolated neutron stars (NSs) show a bewildering variety of astrophysical manifestations, presumably shaped by the magnetic field strength and topology at birth. Here, using state-of-the-art calculations of the coupled magnetic and thermal evolution of NSs, we compute the thermal spectra and pulse profiles expected for a variety of initial magnetic…