Search Publications
Kinematics of the SN Refsdal host revealed by MUSE: a regularly rotating spiral galaxy at z ≃ 1.5
Treu, T.; Grillo, C.; Balestra, I. +11 more
We use Multi Unit Spectroscopic Explorer (MUSE) observations of the galaxy cluster MACS J1149.5+2223 to explore the kinematics of the grand-design spiral galaxy (Sp1149) hosting the supernova `Refsdal'. Sp1149 lies at z ≃ 1.49, has a stellar mass M* ≃ 5 × 109 M⊙, has a star formation rate (SFR) ∼eq 1-6 M_{⊙} yr^{-1…
A Gaia DR2 view of white dwarfs in the Hyades
Salaris, M.; Bedin, L. R.
We have exploited the very precise parallaxes, proper motions, and photometry of Gaia Data Release 2 to study white dwarf members of the Hyades star cluster. Gaia photometry and parallaxes for the eight DA white dwarfs confirmed members have been then used to compute absolute magnitudes and colours. These were compared to three independent sets of…
A remarkable oxygen-rich asymptotic giant branch variable in the Sagittarius Dwarf Irregular Galaxy
Marigo, Paola; Whitelock, Patricia A.; Feast, Michael W. +1 more
We report and discuss JHKS photometry for Sgr dIG, a very metal-deficient galaxy in the Local Group, obtained over 3.5 years with the Infrared Survey Facility in South Africa. Three large amplitude asymptotic giant branch variables are identified. One is an oxygen-rich star that has a pulsation period of 950 d, which was until recently …
AGN feedback in the Phoenix cluster
Liu, H.; Fabian, A. C.; Reynolds, C. S. +5 more
Active galactic nuclei (AGNs) release a huge amount of energy into the intracluster medium, with the consequence of offsetting cooling and star formation (AGN feedback) in the centres of cool-core clusters. The Phoenix cluster is among the most massive clusters of galaxies known in the Universe. It hosts a powerful starburst of several hundreds of…
The origin of the X-ray, radio and H I structures in the NGC 5903 galaxy group
Raychaudhury, Somak; Vrtilek, Jan M.; David, Laurence P. +3 more
The NGC 5903 galaxy group is a nearby (∼30 Mpc) system of ∼30 members, dominated by the giant ellipticals NGC 5903 and NGC 5898. The group contains two unusual structures: a ∼110 kpc long H I filament crossing NGC 5903 and a ∼75 kpc wide diffuse, steep-spectrum radio source of unknown origin that overlaps NGC 5903 and appears to be partly enclosed…
A new look inside planetary nebula LoTr 5: a long-period binary with hints of a possible third component
Montesinos, B.; Lillo-Box, J.; Zorotovic, M. +5 more
LoTr 5 is a planetary nebula with an unusual long-period binary central star. As far as we know, the pair consists of a rapidly rotating G-type star and a hot star, which is responsible for the ionization of the nebula. The rotation period of the G-type star is 5.95 d and the orbital period of the binary is now known to be ∼2700 d, one of the long…
Classifying galaxy spectra at 0.5 < z < 1 with self-organizing maps
Barmby, P.; Teimoorinia, H.; Rahmani, S.
The spectrum of a galaxy contains information about its physical properties. Classifying spectra using templates helps to elucidate the nature of a galaxy's energy sources. In this paper, we investigate the use of self-organizing maps in classifying galaxy spectra against templates. We trained semi-supervised self-organizing map networks using a s…
Connecting optical and X-ray tracers of galaxy cluster relaxation
Parker, Laura C.; Roberts, Ian D.; Hlavacek-Larrondo, Julie
Substantial effort has been devoted in determining the ideal proxy for quantifying the morphology of the hot intracluster medium in clusters of galaxies. These proxies, based on X-ray emission, typically require expensive, high-quality X-ray observations making them difficult to apply to large surveys of groups and clusters. Here, we compare optic…
Modelling interstellar structures around Vela X-1
Gvaramadze, V. V.; Kniazev, A. Y.; Katushkina, O. A. +1 more
We report the discovery of filamentary structures stretched behind the bow-shock-producing high-mass X-ray binary Vela X-1 using the SuperCOSMOS H-alpha Survey and present the results of optical spectroscopy of the bow shock carried out with the Southern African Large Telescope. The geometry of the detected structures suggests that Vela X-1 has en…
A molecular gas-rich GRB host galaxy at the peak of cosmic star formation
Daddi, E.; Elbaz, D.; Le Floc'h, E. +10 more
We report the detection of the CO(3-2) emission line from the host galaxy of gamma-ray burst (GRB) 080207 at z = 2.086. This is the first detection of molecular gas in emission from a GRB host galaxy beyond redshift 1. We find this galaxy to be rich in molecular gas with a mass of 1.1 × 10^{11} M_{{\odot }} assuming αCO = 4.36 M_{{\odot…