Search Publications
The morphologies and masses of extremely red galaxies in the Groth Strip
Cristóbal-Hornillos, D.; López-Sanjuan, C.; Balcells, M. +6 more
We present a new catalogue of EROs from the Groth Strip and study the relation between their morphology and mass. With a selection criterion F814W-Ks≥ 4 and Ks≤ 21.0 we find 102 EROs, over a survey area of 155 arcmin2, leading to a surface density of 0.66 arcmin-2. The photometric data include U, B, F606…
The distance and internal composition of the neutron star in EXO 0748-676 with XMM-Newton
Hiemstra, Beike; Méndez, Mariano; Zhang, Guobao +1 more
Recently, the neutron star X-ray binary EXO 0748-676 underwent a transition to quiescence. We analysed an XMM-Newton observation of this source in quiescence, where we fitted the spectrum with two different neutron star atmosphere models. From the fits we constrained the allowed parameter space in the mass-radius diagram for this source for an ass…
GMRT observations of NGC 2997 and radio detection of the circumnuclear ring
Ananthakrishnan, S.; Kantharia, N. G.; Kodilkar, J.
We present high-resolution, high-sensitivity radio continuum observations of the nearby spiral galaxy NGC 2997 at 332, 616 and 1272 MHz using the Giant Metrewave Radio Telescope (GMRT). The integrated spectrum of this galaxy has a spectral index of -0.92 (Sν ∝ να) and we place an upper limit to the thermal fraction at 1272 MH…
Discovery of the infrared counterpart of CXOU J174437.3-323222 in the field of IGR J17448-3232: a blazar candidate viewed through the Galactic Centre?
Maccarone, T. J.; Chaty, S.; Tomsick, J. A. +2 more
We present our near-infrared ESO-NTT KS band observations of the field of IGR J17448-3232 which show no extended emission consistent with the supernova remnant (SNR), but in which we identify a new counterpart, also visible in Spitzer images up to 24 µm, at the position of the X-ray point source, CXOU J174437.3-323222. Multiwavele…
Ionization structure and Fe Kα energy for irradiated accretion discs
Zhao, Y. H.; Soria, R.; Zhou, X. L.
We study the radial ionization structure at the surface of an X-ray illuminated accretion disc. We plot the expected iron Kα line energy as a function of the Eddington ratio and of the distance of the emitting matter from the central source, for a non-rotating and a maximally rotating black hole. We compare the predicted disc line energies with th…
The abundance of iron-peak elements and the dust composition in η Carinae: manganese
Gull, T. R.; Bautista, M. A.; Hartman, H. +2 more
We study the chemical abundances of the strontium filament found in the ejecta of η Carinae. In particular, we derive the abundances of iron-peak elements from the spectra of their singly ionized ions present in the optical/infrared (IR) spectra. In this paper we analyse the spectrum of Mn II using a new non-local thermodynamic equilibrium (non-LT…
Ground- and space-based study of two globular cluster cataclysmic variables: M22 CV1 and M5 V101
Cool, A. M.; Reynolds, M. T.; Callanan, P. J. +1 more
As a class of compact binaries with large binding energy, cataclysmic variables (CVs) formed through close encounters play an important role in the dynamical evolution of globular clusters. As part of a systematic search for CVs undergoing dwarf nova (DN) eruptions in globular clusters, our 2004 monitoring programme of M22 detected an outburst of …
Multiwavelength study of Chandra X-ray sources in the Antennae
Hayward, T. L.; Brandl, B. R.; Eikenberry, S. S. +7 more
We use Wide-field InfraRed Camera (WIRC) infrared (IR) images of the Antennae (NGC 4038/4039) together with the extensive catalogue of 120 X-ray point sources to search for counterpart candidates. Using our proven frame-tie technique, we find 38 X-ray sources with IR counterparts, almost doubling the number of IR counterparts to X-ray sources that…
Evidence for the nearby F4V star λ Ara as a binary system
Stahl, O.; Chini, R.; Fuhrmann, K. +1 more
We report on the spectroscopic evidence for the nearby, bright and supposedly single F4V star λ Ara as a binary system. The basic observational tracer is a discrepancy with the Hipparcos-based astrometric surface gravity as opposed to the spectroscopically derived value from the pressure-dependent Mg Ib triplet lines. We demonstrate how this discr…
The emission line near 1319 Å in solar and stellar spectra
Jordan, C.
An emission line at ≃1319Å is one of the strongest unidentified lines in the ultraviolet spectra of cool dwarf stars. In most lists of solar and stellar lines it is identified as a transition in N I, although its intensity would then be anomalous and the wavelength does not precisely fit that expected for N I. The line is also observed in giant st…