Search Publications
Inflow of low-metallicity cool gas in the halo of the Andromeda galaxy
Afruni, Andrea; Fraternali, Filippo; Pezzulli, Gabriele
As the closest L* galaxy to our own Milky Way, the Andromeda galaxy (M31) is an ideal laboratory for studies of galaxy evolution. The AMIGA project has recently provided observations of the cool (T ~ 104 K) phase of the circumgalactic medium (CGM) of M31, using HST/COS absorption spectra along ~40 background QSO sightlines, located up t…
Unprecedented change in the position of four radio sources
Frey, Sándor; Melnikov, Alexey; Titov, Oleg +8 more
Astrometric positions of radio-emitting active galactic nuclei (AGNs) can be determined with sub-milliarcsec accuracy using very long baseline interferometry (VLBI). The usually small apparent proper motion of distant extragalactic targets allow us to realize the fundamental celestial reference frame with VLBI observations. However, long-term astr…
Evidence for anisotropic quenching in massive galaxy clusters at z ≈ 0.5
Stott, John P.
A recent observational result finds that the quenching of satellites in groups at z = 0.08 has an angular dependence relative to the semimajor axis of the central galaxy. This observation is described as 'anisotropic quenching' or 'angular conformity'. In this paper, I study the variation in the colour of a mass-limited sample of satellite galaxie…
Dynamics of irregularly shaped cometary particles subjected to outflowing gas and solar radiative forces and torques
Bertini, Ivano; Fulle, Marco; Moreno, Fernando +6 more
The dynamics of irregularly shaped particles subjected to the combined effect of gas drag and radiative forces and torques in a cometary environment is investigated. The equations of motion are integrated over distances from the nucleus surface up to distances where the gas drag is negligible. The aerodynamic forces and torques are computed assumi…
Stellar masses of clumps in gas-rich, turbulent disc galaxies
Glazebrook, Karl; Lenkić, Laura; Fisher, Deanne B. +6 more
In this paper, we use Hubble Space Telescope/WFC3 observations of six galaxies from the DYnamics of Newly Assembled Massive Object (DYNAMO) survey, combined with stellar population modelling of the SED, to determine the stellar masses of DYNAMO clumps. The DYNAMO sample has been shown to have properties similar to z ≈ 1.5 turbulent, clumpy discs. …
Black hole spin measurements based on a thin disc model with finite thickness - I. An example study of MCG-06-30-15
Reynolds, Christopher S.; Abdikamalov, Askar B.; Bambi, Cosimo +1 more
We present a re-analysis of the XMM-Newton and NuSTAR observing campaigns for the well-studied, X-ray-bright AGN MCG-06-30-15. In particular, we consider a disc model with finite thickness. By fitting the disc reflection spectra in the data, we obtain a black hole spin of 0.87-0.99 (90 per cent confidence range) after taking the thickness of the d…
Multi-wavelength constraints on the outflow properties of the extremely bright millisecond radio bursts from the galactic magnetar SGR 1935 + 2154
Murase, Kohta; Kashiyama, Kazumi; Yamasaki, Shotaro
Extremely bright coherent radio bursts with millisecond duration, reminiscent of cosmological fast radio bursts, were codetected with anomalously-hard X-ray bursts from a Galactic magnetar SGR 1935 + 2154. We investigate the possibility that the event was triggered by the magnetic energy injection inside the magnetosphere, thereby producing magnet…
Study of chemically peculiar stars - I. High-resolution spectroscopy and K2 photometry of Am stars in the region of M44
Bhatt, B. C.; García, R. A.; Lund, M. N. +30 more
We present a study based on the high-resolution spectroscopy and K2 space photometry of five chemically peculiar stars in the region of the open cluster M44. The analysis of the high-precision photometric K2 data reveals that the light variations in HD 73045 and HD 76310 are rotational in nature and caused by spots or cloud-like co-rotating struct…
Models of metal-poor stars with different initial abundances of C, N, O, Mg, and Si - I. Bolometric corrections derived from new MARCS synthetic spectra and their implications for observed colour-magnitude diagrams
Casagrande, Luca; Edvardsson, Bengt; VandenBerg, Don A. +1 more
New, high-resolution MARCS synthetic spectra have been calculated for more than a dozen mixtures of the metals allowing, in turn, for variations in C:N:O, [CNO/Fe], and enhanced abundances of C, O, Mg, and Si. Bolometric corrections (BCs) for many of the broad-band filters currently in use have been generated from these spectra. Due to improved tr…
Comparing the super-Eddington accretion of SMC X-3 and RX J0209.6-7427 with Swift J0243.6+6124
Weng, Shan-Shan; Liu, Jiren; Vasilopoulos, Georgios +4 more
We study the giant outbursts of SMC X-3 and RX J0209.6-7427 (hereafter RX J0209) to compare their super-Eddington accretion regime with that of Swift J0243.6+6124 (hereafter Swift J0243). The high double-peak profile of SMC X-3 is found to be 0.25 phase offset from that below 2.3 × 1038 erg s-1, which is similar to Swift J024…