arXiv subjects

Elisa Antolini

Publications and source records attributed to Elisa Antolini.

4 recordsLinked to original sources

arXiv2016

Using Galaxy Formation Simulations to optimise LIGO Follow-Up Observations

The recent discovery of gravitational radiation from merging black holes poses a challenge of how to organize the electromagnetic follow-up of gravitational-wave events as well as observed bursts of neutrinos. We propose a technique to select the galaxies that are most likely to host the event given some assumptions of whether the particular event is associated with recent star formation, low metallicity stars or simply proportional to the total stellar mass in the galaxy. We combine data from the 2-MASS Photometric Redshift Galaxy Catalogue with results from galaxy formation simulations to develop observing strategies that potentially reduce the area of sky to search by up to a factor of two relative to an unweighted search of galaxies, and a factor twenty to a search over the entire LIGO localization region.

astro-ph.HE↗

arXiv2016

Using the 2-MASS Photometric Redshift Survey to optimize LIGO Follow-Up Observations

The initial discovery of LIGO on 14 September 2015 was the inspiral merger and ring-down of the black hole binary at a distance of about 500~Mpc or a redshift of about 0.1. The search for electromagnetic counterparts for the inspiral of binary black holes is impeded by coarse initial source localisations and a lack of a compelling model for the counterpart; therefore, rapid electromagnetic follow-up is required to understand the astrophysical context of these sources. Because astrophysical sources of gravitational radiation are likely to reside in galaxies, it would make sense to search first in regions where the LIGO-Virgo probability is large and where the density of galaxies is large as well. Under the assumption that the probability of a gravitational-wave event from a given region of space is proportional to the density of galaxies within the probed volume, one can calculate an improved localisation of the position of the source simply by multiplying the LIGO-Virgo skymap by the density of galaxies in the range of redshifts. We propose using the 2-MASS Photometric Redshift Galaxy Catalogue for this purpose and demonstrate that using it can dramatically reduce the search region for electromagnetic counterparts.

astro-ph.HE↗

arXiv2015

When do stars in 47 Tucanae lose their mass?

By examining the diffusion of young white dwarfs through the core of the globular cluster 47 Tucanae, we estimate the time when the progenitor star lost the bulk of its mass to become a white dwarf. According to stellar evolution models of the white-dwarf progenitors in 47 Tucanae, we find this epoch to coincide approximately with the star ascending the asymptotic giant branch ($3.0 \pm 8.1$ Myr before the tip of the AGB) and more than ninety million years after the helium flash (with ninety-percent confidence). From the diffusion of the young white dwarfs we can exclude the hypothesis that the bulk of the mass loss occurs on the red-giant branch at the four-sigma level. Furthermore, we find that the radial distribution of horizontal branch stars is consistent with that of the red-giant stars and upper-main-sequence stars and inconsistent with the loss of more than 0.2 solar masses on the red-giant branch at the six-sigma level.

astro-ph.SR↗

arXiv2015

A Measurement of Diffusion in 47 Tucanae

Using images from the Hubble Space Telescope Wide-Field Camera 3, we measure the rate of diffusion of stars through the core of the globular cluster 47 Tucanae using a sample of young white dwarfs identified in these observations. This is the first direct measurement of diffusion due to gravitational relaxation. We find that the diffusion rate $κ\approx 10-13$ arcsecond$^2$ Myr$^{-1}$ is consistent with theoretical estimates of the relaxation time in the core of 47 Tucanae of about 70 Myr.

astro-ph.SR↗