Search Publications
A nitrogen-enhanced metal-poor star discovered in the globular cluster ESO280-SC06
Martell, Sarah L.; Simpson, Jeffrey D.
We report the discovery of the only very nitrogen-enhanced metal-poor star known in a Galactic globular cluster. This star, in the very metal-poor cluster ESO280-SC06 , has [N/Fe] > +2.5, while the other stars in the cluster show no obvious enhancement in nitrogen. Around 80 NEMP stars are known in the field, and their abundance patterns are be…
Discovery of a transient ultraluminous X-ray source in the elliptical galaxy M86
Kundu, Arunav; Zepf, Stephen E.; Maccarone, Thomas J. +2 more
We report the discovery of the transient ultraluminous X-ray source (ULX) CXOU J122602.3+125951 (hereafter M86 tULX-1), located 3'52″ (19 kpc) north-west of the centre of the giant elliptical galaxy M86 (NGC 4406) in the Virgo Cluster. The spectrum of M86 tULX-1 can be fit by a power law plus multicolour disc model with a 1.0^{+0.8}_{-2.6} index a…
A GMRT 150 MHz search for variables and transients in Stripe 82
Frail, D. A.; Mooley, K. P.; Intema, H. T. +1 more
We have carried out a dedicated transient survey of 300 deg2 of the SDSS Stripe 82 region using the Giant Metrewave Radio Telescope (GMRT) at 150 MHz. Our multi-epoch observations, together with the TGSS survey, allow us to probe variability and transient activity on four different time-scales, beginning with 4 h and up to 4 yr. Data ca…
2PBC J0658.0-1746: a hard X-ray eclipsing polar in the orbital period gap
Mukai, K.; de Martino, D.; Masetti, N. +2 more
The hard X-ray source 2PBC J0658.0-1746 was proposed as an eclipsing magnetic cataclysmic variable of the polar type, based on optical follow-ups. We present the first spectral and timing analysis at X-ray energies with XMM-Newton, complemented with archival X-ray, optical, infrared (IR) photometry, and spectroscopy. The X-ray emission shows brigh…
The peculiar chemistry of the inner ejecta of Eta Carina
Bordiu, Cristobal; Rizzo, J. Ricardo
We investigated continuum and molecular line emission of four species (CO, HCN, H13CN, and HCO+) at 0.8 mm in the inner region around η Car, using ALMA archival observations at a resolution better than 0.2 arcsec. We report the discovery of an asymmetric extended structure north-west of the star, independent from the continuu…
Improving statistical sensitivity of X-ray searches for axion-like particles
Conlon, Joseph P.; Rummel, Markus
X-ray observations of bright AGNs in or behind galaxy clusters offer unique capabilities to constrain axion-like particles. Existing analysis technique relies on measurements of the global goodness of fit. We develop a new analysis methodology that improves the statistical sensitivity to ALP-photon oscillations by isolating the characteristic quas…
V752 Cen - a triple-lined spectroscopic contact binary with sudden and continuous period changes
Zhou, X.; Qian, S. -B.; Fernández Lajús, E. +1 more
V752 Cen is a triple-lined spectroscopic contact binary. Its multicolour light curves were obtained in the years 1971 and 2018, independently. Photometric analyses reveal that the two sets of light curves produce almost consistent results. It contains a W-subtype totally eclipsing binary, and its mass ratio and fill-out factor are q = 3.35(1) and …
XMM-Newton observations of the symbiotic recurrent nova T CrB: evolution of X-ray emission during the active phase
Zhekov, Svetozar A.; Tomov, Toma V.
We present an analysis of the XMM-Newton observations of the symbiotic recurrent nova T CrB, obtained during its active phase which started in 2014-2015. The XMM-Newton spectra of T CrB have two prominent components: a soft one (0.2-0.6 keV), well represented by blackbody emission, and a heavily absorbed hard component (2-10 keV), well matched by …
What information can we derive from historical Far Eastern guest stars for modern research on novae and cataclysmic variables?
Hoffmann, Susanne M.
Recently, there have been several studies on the evolution of binary systems using historical data that are treated as facts in the chain of argument. This paper discusses six case studies of modern dwarf novae with suggested historical counterparts from the historical point of view, as well as the derived consequences for the physics of close bin…
The study of unclassified B[e] stars and candidates in the Galaxy and Magellanic Clouds†
Borges Fernandes, M.; Condori, C. A. H.; Kraus, M. +2 more
We investigated 12 unclassified B[e] stars or candidates, 8 from the Galaxy, 2 from the Large Magellanic Cloud (LMC), and 2 from the Small Magellanic Cloud (SMC). Based on the analysis of high-resolution spectroscopic (FEROS) and photometric data, we confirmed the presence of the B[e] phenomenon for all objects of our sample, except for one (IRAS …