Search Publications
Circumstellar CO J = 3→2 detected around the evolving metal-poor ([Fe/H] ≈ -1.15 dex) AGB star RU Vulpeculae
Zijlstra, A. A.; Richards, A. M. S.; McDonald, I. +2 more
We report the first detection of CO J = 3→2 around a truly metal-poor evolved star. RU Vulpeculae is modelled to have Teff ≈ 3620 K, L ≈ 3128 ± 516 L⊙, log(g) = 0.0 ± 0.2 dex and [Fe/H] = -1.3 to -1.0 dex, and is modelled to have recently undergone a thermal pulse. Its infrared flux has approximately doubled over 35 yr. ALMA …
Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud - V. Multiple populations in ancient globular clusters
Ventura, Paolo; Cohen, Roger E.; Sarajedini, Ata +10 more
We examine four ancient Large Magellanic Cloud (LMC) globular clusters (GCs) for evidence of multiple stellar populations using the Advanced Camera for Surveys and Wide Field Camera 3 on the Hubble Space Telescope Programme GO-14164. NGC 1466, NGC 1841, and NGC 2257 all show evidence for a redder, secondary population along the main sequence. Reti…
Abundances from integrated spectra of 47 Tucanae (NGC 104)
Trevisan, M.; Barbuy, B.; Rennó, C. +1 more
47 Tucanae is among the most studied and observed globular clusters, given its proximity. The aim of this work is to study in detail the integrated spectrum of 47 Tucanae, as a template, in order to have a list of reliable lines that are validated for a moderate spectral resolution case. The spectrum of 47 Tucanae is reproduced by computing synthe…
Search for the optical counterpart of the GW170814 gravitational wave event with the VLT Survey Telescope
Covino, S.; Campana, S.; Della Valle, M. +30 more
We report on the search for the optical counterpart of the gravitational event GW170814, which was carried out with the VLT Survey Telescope (VST) by the GRAvitational Wave Inaf TeAm. Observations started 17.5 h after the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo alert and we covered an area of 99 deg2 that en…
Evolving pulsation of the slowly rotating magnetic β Cep star ξ1 CMa
Handler, G.; Wade, G. A.; Pigulski, A. +11 more
Recent BRITE-Constellation space photometry of the slowly rotating, magnetic β Cep pulsator ξ1 CMa permits a new analysis of its pulsation properties. Analysis of the two-colour BRITE data reveals the well-known single pulsation period of 0.209 d, along with its first and second harmonics. A similar analysis of SMEI and TESS observation…
A white dwarf bound to the transiting planetary system WASP-98
Gänsicke, Boris T.; Močnik, Teo; Tremblay, Pier-Emmanuel +2 more
WASP-98 is a planetary system containing a hot Jupiter transiting a late-G dwarf. A fainter star, 12 arcsec away, has previously been identified as a white dwarf, with a distance and proper motion consistent with a physical association with the planetary system. We present spectroscopy of the white dwarf, with the aim of determining its mass, radi…
A search for pulsars in subdwarf B binary systems and discovery of giant-pulse emitting PSR J0533-4524
Ishwara-Chandra, C. H.; van Leeuwen, J.; Coenen, T. +2 more
Binary millisecond pulsars (MSPs) provide several opportunities for research of fundamental physics. However, finding them can be challenging. Several subdwarf B (sdB) binary systems with possible neutron star companions have been identified, allowing us to perform a targeted search for MSPs within these systems. Six sdBs with companions in the ne…
The excitation temperature of the CH 3335-MHz line
Reach, William T.; Andersson, B. -G.; Dailey, Erin M. +2 more
Molecular hydrogen is the main constituent of dense molecular clouds, but is expected to also be a dominant constituent in many environments where CO can no longer be seen, the so-called 'CO-dark molecular gas'. Based on comparisons of ultraviolet spectroscopy of H2 and optical line observations (4300 Å), CH is a prime candidate to trac…
Eclipse timing variation of GK Vir: evidence of a possible Jupiter-like planet in a circumbinary orbit
Almeida, L. A.; Pereira, E. S.; Borges, G. M. +3 more
Eclipse timing variation analysis has become a powerful method to discover planets around binary systems. We applied this technique to investigate the eclipse times of GK Vir. This system is a post-common envelope binary with an orbital period of 8.26 h. Here, we present 10 new eclipse times obtained between 2013 and 2020. We calculated the O-C di…
Is Fornax 4 the nuclear star cluster of the Fornax dwarf spheroidal galaxy?
Martocchia, S.; Dalessandro, E.; Salaris, M. +2 more
Fornax 4 is the most distinctive globular cluster in the Fornax dwarf spheroidal. Located close to the centre of the galaxy, more metal-rich and potentially younger than its four companions (namely, Fornax clusters number 1, 2, 3, and 5), it has been suggested to have experienced a different formation than the other clusters in the galaxy. Here, w…