145 research outputs found
Field tests for the ESPRESSO data analysis software
The data analysis software (DAS) for VLT ESPRESSO is aimed to set a new
benchmark in the treatment of spectroscopic data towards the
extremely-large-telescope era, providing carefully designed, fully interactive
recipes to take care of complex analysis operations (e.g. radial velocity
estimation in stellar spectra, interpretation of the absorption features in
quasar spectra). A few months away from the instrument's first light, the DAS
is now mature for science validation, with most algorithms already implemented
and operational. In this paper, I will showcase the DAS features which are
currently employed on high-resolution HARPS and UVES spectra to assess the
scientific reliability of the recipes and their range of application. I will
give a glimpse on the science that will be possible when ESPRESSO data become
available, with a particular focus on the novel approach that has been adopted
to simultaneously fit the emission continuum and the absorption lines in the
Lyman-alpha forest of quasar spectra.Comment: 4 pages, 1 figure; proceedings of ADASS XXVI, accepted by ASP
Conference Serie
Data Analysis Software for the ESPRESSO Science Machine
ESPRESSO is an extremely stable high-resolution spectrograph which is
currently being developed for the ESO VLT. With its groundbreaking
characteristics it is aimed to be a "science machine", i.e., a fully-integrated
instrument to directly extract science information from the observations. In
particular, ESPRESSO will be the first ESO instrument to be equipped with a
dedicated tool for the analysis of data, the Data Analysis Software (DAS),
consisting in a number of recipes to analyze both stellar and quasar spectra.
Through the new ESO Reflex GUI, the DAS (which will implement new algorithms to
analyze quasar spectra) is aimed to get over the shortcomings of the existing
software providing multiple iteration modes and full interactivity with the
data.Comment: 5 pages, 2 figures; proceedings of ADASS XXI
Volatiles and refratories in solar analogs: no terrestial planet connection
We have analysed very high-quality HARPS and UVES spectra of 95 solar
analogs, 24 hosting planets and 71 without detected planets, to search for any
possible signature of terrestial planets in the chemical abundances of volatile
and refractory elements with respect to the solar abundances. We demonstrate
that stars with and without planets in this sample show similar mean abundance
ratios, in particular, a sub-sample of 14 planet-host and 14 "single" solar
analogs in the metallicity range 0.14<[Fe/H]<0.36. In addition, two of the
planetary systems in this sub-sample, containing each of them a
super-Earth-like planet with masses in the range ~ 7-11 Earth masses, have
different volatile-to-refratory abundance ratios to what would be expected from
the presence of a terrestial planets. Finally, we check that after removing the
Galactic chemical evolution effects any possible difference in mean abundances,
with respect to solar values, of refratory and volatile elements practically
dissappears.Comment: 2 pages, 2 figures, to appear in the proceedings of the 276th IAU
Symposium "The Astrophysics of Planetary Systems
A possible surviving companion of the SN Ia in the Galactic SNR G272.2-3.2
We use the {\it Gaia} EDR3 to explore the Galactic supernova remnant SNR
G272.2-3.2, produced by the explosion of a Type Ia supernova (SNIa), about
7,500 years ago, to search for a surviving companion. From the abundances in
the SNR ejecta, G272.2-3.2 is a normal SN Ia. The {\it Gaia} parallaxes allow
to select the stars located within the estimated distance range of the SNR, and
the {\it Gaia} proper motions to study their kinematics. From the {\it Gaia}
EDR3 photometry, we construct the HR diagram of the selected sample, which we
compare with the theoretical predictions for the evolution of possible star
companions of SNIa. We can discard several proposed types of companions by
combining kinematics and photometry. We can also discard hypervelocity stars.
We focus our study on the kinematically most peculiar star, {\it Gaia} EDR3
5323900215411075328 (hereafter MV-G272), a 8.9 outlier in proper
motion. It is of M1-M2 stellar type. Its trajectory on the sky locates it at
the center of the SNR, 6,000--8,000 years ago, a unique characteristic among
the the sample. Spectra allow a stellar parameters determination and a chemical
abundance analysis. In conclusion, we have a candidate to be the surviving
companion of the SN Ia that resulted in SNR G272.2-3.2. It is supported by its
kinematical characteristics and its trajectory within the SNR. This opens the
possibility of a single-degenerate scenario for a SN Ia with an M-type dwarf
companion.Comment: 35 pages, 19 Figures, 5 Tables, published as ApJ 947, 90
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