Search Publications
Atmospheric stellar parameters for large surveys using FASMA, a new spectral synthesis package
Sousa, S. G.; Santos, N. C.; Bruzual, G. +4 more
In the era of vast spectroscopic surveys focusing on Galactic stellar populations, astronomers want to exploit the large quantity and good quality of data to derive their atmospheric parameters without losing precision from automatic procedures. In this work, we developed a new spectral package, FASMA, to estimate the stellar atmospheric parameter…
Signature of inverse Compton emission from blazars
Gaur, Haritma; Mohan, Prashanth; Wierzcholska, Alicja +1 more
Blazars are classified into high-, intermediate- and low-energy-peaked sources based on the location of their synchrotron peak. This lies in infra-red/optical to ultra-violet bands for low- and intermediate-peaked blazars. The transition from synchrotron to inverse Compton emission falls in the X-ray bands for such sources. We present the spectral…
Multiplicity of disc-bearing stars in Upper Scorpius and Upper Centaurus-Lupus
Federrath, Christoph; Bento, Joao; Ireland, Michael +2 more
We present observations of disc-bearing stars in Upper Scorpius (US) and Upper Centaurus-Lupus (UCL) with moderate resolution spectroscopy in order to determine the influence of multiplicity on disc persistence after ∼ 5-20 Myr. Discs were identified using infrared (IR) excess from the Wide-field Infrared Survey Explorer (WISE) survey. Our survey …
The Carnegie RR Lyrae Program: mid-infrared period-luminosity relations of RR Lyrae stars in Reticulum
Madore, Barry F.; Freedman, Wendy L.; Scowcroft, Victoria +4 more
We analysed 30 RR Lyrae stars (RRLs) located in the Large Magellanic Cloud (LMC) globular cluster Reticulum that were observed in the 3.6 and 4.5 µ m passbands with the Infrared Array Camera (IRAC) on board the Spitzer Space Telescope. We derived new mid-infrared (MIR) period-luminosity (PL) relations. The zero points of the PL relations wer…
The shape of galaxy dark matter haloes in massive galaxy clusters: insights from strong gravitational lensing
Massey, Richard; Jauzac, Mathilde; Harvey, David
We assess how much unused strong lensing information is available in the deep Hubble Space Telescope imaging and Very Large Telescope/Multi Unit Spectroscopic Explorer spectroscopy of the Frontier Field clusters. As a pilot study, we analyse galaxy cluster MACS J0416.1-2403 (z = 0.397, M(R < 200 kpc) = 1.6 × 1014 M⊙), whic…
Alone on a wide wide sea. The origin of SECCO 1, an isolated star-forming gas cloud in the Virgo cluster*†‡
Bellazzini, M.; Testa, V.; Beccari, G. +12 more
SECCO 1 is an extremely dark, low-mass (M⋆ ≃ 105 M⊙), star-forming stellar system lying in the low-velocity cloud (LVC) substructure of the Virgo cluster of galaxies, and hosting several H II regions. Here, we review our knowledge of this remarkable system, and present the results of (a) additional analysis of our …
The PHEMU15 catalogue and astrometric results of the Jupiter's Galilean satellite mutual occultation and eclipse observations made in 2014-2015
Delcroix, M.; Colas, F.; Carry, B. +116 more
During the 2014-2015 mutual events season, the Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE), Paris, France, and the Sternberg Astronomical Institute (SAI), Moscow, Russia, led an international observation campaign to record ground-based photometric observations of Galilean moon mutual occultations and eclipses. We focused on …
Unbiased TGAS×LAMOST distances and the role of binarity
Rix, Hans-Walter; Coronado, Johanna; Trick, Wilma H.
Spectrophotometric distances to stars observed by large spectroscopic surveys offer a crucial complement to parallax distances that remain very important also after the future Gaia data releases. Here, we present a probabilistic approach to modelling spectroscopic information for a subset of 4000 main sequence stars with good parallaxes (σϖ
NuSTAR + XMM-Newton monitoring of the neutron star transient AX J1745.6-2901
Hailey, C.; Stern, D.; Bianchi, S. +12 more
AX J1745.6-2901 is a high-inclination (eclipsing) transient neutron star (NS) low-mass X-ray binary showcasing intense ionized Fe K absorption. We present here the analysis of 11 XMM-Newton and 15 NuSTAR new data sets (obtained between 2013 and 2016), therefore tripling the number of observations of AX J1745.6-2901 in outburst. Thanks to simultane…
Limits on turbulent propagation of energy in cool-core clusters of galaxies
Fabian, A. C.; Reynolds, C. S.; Pinto, C. +2 more
We place constraints on the propagation velocity of bulk turbulence within the intracluster medium of three clusters and an elliptical galaxy. Using Reflection Grating Spectrometer measurements of turbulent line broadening, we show that for these clusters, the 90 per cent upper limit on turbulent velocities when accounting for instrumental broaden…