Search Publications
Chemical abundances in the multiple sub-giant branch of 47 Tucanae: insights on its faint sub-giant branch component
Milone, A. P.; Marino, A. F.; Bedin, L. R. +8 more
The globular cluster 47 Tuc exhibits a complex sub-giant branch (SGB) with a faint-SGB comprising only about the 10 per cent of the cluster mass and a bright-SGB hosting at least two distinct populations. We present a spectroscopic analysis of 62 SGB stars including 21 faint-SGB stars. We thus provide the first chemical analysis of the intriguing …
The 80 Ms follow-up of the X-ray afterglow of GRB 130427A challenges the standard forward shock model
Troja, E.; Piro, L.; Page, M. J. +12 more
GRB 130427A was the brightest gamma-ray burst detected in the last 30 yr. With an equivalent isotropic energy output of 8.5 × 1053 erg and redshift z = 0.34, it uniquely combined very high energetics with a relative proximity to Earth. As a consequence, its X-ray afterglow has been detected by sensitive X-ray observatories such as XMM-N…
Monsters in the dark: predictions for luminous galaxies in the early Universe from the BLUETIDES simulation
Wilkins, Stephen M.; Nagai, Daisuke; Croft, Rupert +3 more
Using deep Hubble and Spitzer observations Oesch et al. have identified a bright (MUV ≈ -22) star-forming galaxy candidate at z ≈ 11. The presence of GN-z11 implies a number density ∼10-6 Mpc-3, roughly an order of magnitude higher than the expected value based on extrapolations from lower redshift. Using the unpre…
Overconfidence in photometric redshift estimation
Wittman, David; Bhaskar, Ramya; Tobin, Ryan
We describe a new test of photometric redshift performance given a spectroscopic redshift sample. This test complements the traditional comparison of redshift differences by testing whether the probability density functions p(z) have the correct width. We test two photometric redshift codes, BPZ and EAZY, on each of two data sets and find that BPZ…
A weak gravitational lensing recalibration of the scaling relations linking the gas properties of dark haloes to their mass
Wang, Wenting; White, Simon D. M.; Mandelbaum, Rachel +3 more
We use weak gravitational lensing to measure mean mass profiles around locally brightest galaxies (LBGs). These are selected from the Seventh Data Release of the Sloan Digital Sky Survey spectroscopic and photometric catalogues to be brighter than any neighbour projected within 1.0 Mpc and differing in redshift by <1000 km s-1. Most …
Timing of the accreting millisecond pulsar SAX J1748.9-2021 during its 2015 outburst
Sanna, A.; Di Salvo, T.; Burderi, L. +6 more
We report on the timing analysis of the 2015 outburst of the intermittent accreting millisecond X-ray pulsar SAX J1748.9-2021 observed on March 4 by the X-ray satellite XMM-Newton. By phase connecting the time of arrivals of the observed pulses, we derived the best-fitting orbital solution for the 2015 outburst. We investigated the energy pulse pr…
Abundance ratios and IMF slopes in the dwarf elliptical galaxy NGC 1396 with MUSE
Smith, R.; Peletier, R. F.; Paolillo, M. +16 more
Deep observations of the dwarf elliptical (dE) galaxy NGC 1396 (MV = -16.60, Mass ∼4 × 108 M⊙), located in the Fornax cluster, have been performed with the Very Large Telescope/Multi Unit Spectroscopic Explorer spectrograph in the wavelength region from 4750 to 9350 Å. In this paper, we present a stellar population…
Striations in the Taurus molecular cloud: Kelvin-Helmholtz instability or MHD waves?
Falgarone, E.; Goldsmith, P. F.; Yıldız, U. A. +3 more
The origin of striations aligned along the local magnetic field direction in the translucent envelope of the Taurus molecular cloud is examined with new observations of 12CO and 13CO J = 2-1 emission obtained with the 10-m Submillimeter Telescope of the Arizona Radio Observatory. These data identify a periodic pattern of exce…
An enhanced fraction of starbursting galaxies among high Eddington ratio AGNs
Daddi, E.; Ciesla, L.; Mullaney, J. R. +2 more
We investigate the star-forming properties of 1620 X-ray selected active galactic nuclei (AGN) host galaxies as a function of their specific X-ray luminosity (I.e. X-ray luminosity per unit host stellar mass) - a proxy of the Eddington ratio. Our motivation is to determine whether there is any evidence of a suppression of star formation at high Ed…
Lightning climatology of exoplanets and brown dwarfs guided by Solar system data
Helling, Ch.; Hodosán, G.; Asensio-Torres, R. +2 more
Clouds form on extrasolar planets and brown dwarfs where lightning could occur. Lightning is a tracer of atmospheric convection, cloud formation and ionization processes as known from the Solar system, and may be significant for the formation of prebiotic molecules. We study lightning climatology for the different atmospheric environments of Earth…