A high-resolution spectropolarimetric survey of Herbig Ae/Be stars – I. Observations and measurements★

Abstract

This is the first in a series of papers in which we describe and report the\nanalysis of a large survey of Herbig Ae/Be stars in circular\nspectropolarimetry. Using the ESPaDOnS and Narval high-resolution\nspectropolarimeters at the Canada-France-Hawaii and Bernard Lyot Telescopes,\nrespectively, we have acquired 132 circularly-polarised spectra of 70 Herbig\nAe/Be stars and Herbig candidates. The large majority of these spectra are\ncharacterised by a resolving power of about 65,000, and a spectral coverage\nfrom about 3700 ang to 1 micron. The peak SNR per CCD pixel ranges from below\n100 (for the faintest targets) to over 1000 (for the brightest). The\nobservations were acquired with the primary aim of searching for magnetic\nfields in these objects. However, our spectra are suitable for a variety of\nother important measurements, including rotational properties, variability,\nbinarity, chemical abundances, circumstellar environment conditions and\nstructure, etc. In this first paper, we describe the sample selection, the\nobservations and their reduction, and the measurements that will comprise the\nbasis of much of our following analysis. We describe the determination of\nfundamental parameters for each target. We detail the Least-Squares\nDeconvolution that we have applied to each of our spectra, including the\nselection, editing and tuning of the LSD line masks. We describe the fitting of\nthe LSD Stokes I profiles using a multi-component model that yields the\nrotationally-broadened photospheric profile (providing the projected rotational\nvelocity and radial velocity for each observation) as well as circumstellar\nemission and absorption components. Finally, we diagnose the longitudinal\nZeeman effect via the measured circular polarisation, and report the\nlongitudinal magnetic field and Stokes V Zeeman signature detection\nprobability. As an appendix, we provide a detailed review of each star\nobserved.\n