Search Publications
Results from the SuperModel analysis of the X-COP galaxy clusters sample
Fusco-Femiano, Roberto
In this work, the analysis of the stacked projected temperature profile of 12 galaxy clusters of the X-COP sample is performed via the SuperModel, a tool for investigating the intracluster medium thermodynamic properties already tested on many clusters since 2009. Two separate fits have been carried out: to the joint X-ray and SZ-projected tempera…
A catalogue of nuclear stellar velocity dispersions of nearby galaxies from Hα STIS spectra to constrain supermassive black hole masses
Sarzi, Marc; Dalla Bontà, Elena; Corsini, Enrico Maria +4 more
We present new measurements for the nuclear stellar velocity dispersion σ* within sub-arcsecond apertures for 28 nearby galaxies. Our data consist of Space Telescope Imaging Spectrograph (STIS) long-slit spectra obtained with the G750M grating centred on the Hα spectral range. We fit the spectra using a library of single stellar populat…
High-resolution spectroscopy of Boyajian's star during optical dimming events
Simón-Díaz, S.; Collier Cameron, A.; González Hernández, J. I. +13 more
Boyajian's star is an apparently normal main-sequence F-type star with a very unusual light curve. The dipping activity of the star, discovered during the Kepler mission, presents deep, asymmetric, and aperiodic events. Here we present high-resolution spectroscopic follow-up during some dimming events recorded post-Kepler observations, from ground…
Parameter estimation for scarce stellar populations
Bitsakis, T.; Bruzual, G.; Cervantes Sodi, B. +1 more
We present a Bayesian method to determine simultaneously the age, metallicity, distance modulus, and interstellar reddening by dust of any resolved stellar population, by comparing the observed and synthetic colour magnitude diagrams on a star by star basis, with no need to bin the data into a carefully selected magnitude grid. We test the method …
Absolute parameters of young stars: HX Velorum
Demircan, O.; Özkardeş, B.; Erdem, A. +4 more
We present combined photometric and spectroscopic analyses of the southern multiple star HX Vel. High-resolution spectra of this system were taken at the University of Canterbury Mt. John Observatory in the years 2009-2015. Absolute parameters for HX Vel tend to confirm its young and near-main-sequence nature. We specify the main adopted parameter…
A high signal-to-noise HST spectrum towards J1009+0713: precise absorption measurements in the CGM of two galaxies
Nicastro, Fabrizio; Mathur, Smita; Weinberg, David H. +6 more
High signal-to-noise spectra towards background quasars are crucial for uncovering weak absorption in the circumgalactic medium (CGM) of intervening galaxies, such as the diagnostic lines of N V that provide insight to the ionization process of warm gas but typically have low equivalent widths. We present a new spectrum from the Hubble Space Teles…
Differential astrometric framework for the Jupiter relativistic experiment with Gaia
Abbas, Ummi; Bucciarelli, Beatrice; Lattanzi, Mario G.
We employ differential astrometric methods to establish a small field reference frame stable at the microarcsecond (µas) level on short time-scales using high-cadence simulated observations taken by Gaia in 2017 February of a bright star close to the limb of Jupiter, as part of the relativistic experiment on Jupiter's quadrupole. We achieve …
Photometry and colour index of Comet 67P/Churyumov-Gerasimenko on 2015 December 12
Lasue, J.; Sen, A. K.; Gupta, R. +3 more
Comet 67P/Churyumov-Gerasimenko (hereafter, 67P) was observed on 2015 December 12, from 2 m Himalayan Chandra Telescope in India in photometry to study its dust properties, using Bessell R and I filters. We study the photometric images to highlight coma structures and jets. The radial decrease in intensity in the different coma structures is compa…
Infrared imaging of high-mass young stellar objects: evidence of multiple shocks and of a new protostar/star eclipsing system
Tapia, Mauricio; Persi, Paolo
We present deep near- and mid-infrared images of six high-mass young stellar objects (YSOs) in order to help understand the physical mechanisms of their formation. We have searched for shocked H2 emission around such massive protostars. All but one of these regions exhibit series of molecular hydrogen emission knots, either in perfect a…
AT 2017fvz: a nova in the dwarf irregular galaxy NGC 6822
Zheng, W.; Filippenko, A. V.; Henze, M. +7 more
A transient in the Local Group dwarf irregular galaxy NGC 6822 (Barnard's Galaxy) was discovered on 2017 August 2 and is only the second classical nova discovered in that galaxy. We conducted optical, near-ultraviolet, and X-ray follow-up observations of the eruption, the results of which we present here. This `very fast' nova had a peak V-band ma…