Spectrophotometrically Identified stars in the PEARS-N and PEARS-S fields - Astrophysics > Astrophysics of GalaxiesReport as inadecuate




Spectrophotometrically Identified stars in the PEARS-N and PEARS-S fields - Astrophysics > Astrophysics of Galaxies - Download this document for free, or read online. Document in PDF available to download.

Abstract: Deep ACS slitless grism observations and identification of stellar sourcesare presented within the Great Observatories Origins Deep Survey GOODS Northand South fields which were obtained in the Probing Evolution And ReionizationSpectroscopically PEARS program. It is demonstrated that even low resolutionspectra can be a very powerful means to identify stars in the field, especiallylow mass stars with stellar types M0 and later. The PEARS fields lay within thelarger GOODS fields, and we used new, deeper images to further refine theselection of stars in the PEARS field, down to a magnitude of mz = 25 using anewly developed stellarity parameter. The total number of stars with reliablespectroscopic and morphological identification was 95 and 108 in the north andsouth fields respectively. The sample of spectroscopically identified starsallows constraints to be set on the thickness of the Galactic thin disk as wellas contributions from a thick disk and a halo component. We derive a thin diskscale height, as traced by the population of M4 to M9 dwarfs along twoindependent lines of sight, of h thin = 370 +60-65 pc. When including the moremassive M0 to M4 dwarf population, we derive h thin = 300 +- 70pc. In bothcases, we observe that we must include a combination of thick and halocomponents in our models in order to account for the observed numbers of faintdwarfs. The required thick disk scale height is typically h thick=1000 pc andthe acceptable relative stellar densities of the thin disk to thick disk andthe thin disk to halo components are in the range of 0.00025


Author: N. Pirzkal, A. J. Burgasser, S. Malhotra, B. W. Holwerda, K. C. Sahu, J. E. Rhoads, C. Xu, J. J. Bochanski, J. R. Walsh, R. A. Wi

Source: https://arxiv.org/







Related documents