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Title: The LMC geometry and outer stellar populations from early DES data

Abstract

The Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey (DES). The SV footprint covers a large portion of the outer Large Magellanic Cloud (LMC), providing photometry 1.5 mag fainter than the main sequence turn-off of the oldest LMC stellar population. We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = -38 degrees.14 +/- 0 degrees.08 (near side in the north) and a position angle for the line of nodes of theta(0) = 129 degrees.51 +/- 0 degrees.17. We find that stars younger than similar to 4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R->4Gyr = 1.41 +/- 0.01 kpc, while the younger population has R-<4Gyr = 0.72 +/- 0.01 kpc. However, the spatial distribution of the younger population deviates significantly from the projected exponential disc model. The distribution of old stars suggests a large truncation radius of R-t = 13.5 +/- 0.8 kpc. If this truncation is dominated by the tidal field ofmore » the Galaxy, we find that the LMC is similar or equal to 24(-6)(+9) times less massive than the encircled Galactic mass. By measuring the Red Clump peak magnitude and comparing with the best-fitting LMC disc model, we find that the LMC disc is warped and thicker in the outer regions north of the LMC centre. Our findings may either be interpreted as a warped and flared disc in the LMC outskirts, or as evidence of a spheroidal halo component.« less

Authors:
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Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
OSTI Identifier:
1342914
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Monthly Notices of the Royal Astronomical Society; Journal Volume: 449; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Balbinot, E., Santiago, B. X., Girardi, L., Pieres, A., da Costa, L. N., Maia, M. A. G., Gruendl, R. A., Walker, A. R., Yanny, B., Drlica-Wagner, A., Benoit-Levy, A., Abbott, T. M. C., Allam, S. S., Annis, J., Bernstein, J. P., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Rosell, A. C., Cunha, C. E., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Estrada, J., Evrard, A. E., Neto, A. F., Finley, D. A., Flaugher, B., Frieman, J. A., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., March, M., Marshall, J. L., Miller, C., Miquel, R., Ogando, R., Peoples, J., Plazas, A., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Tucker, D. L., Wechsler, R., and Zuntz, J. The LMC geometry and outer stellar populations from early DES data. United States: N. p., 2015. Web. doi:10.1093/mnras/stv356.
Balbinot, E., Santiago, B. X., Girardi, L., Pieres, A., da Costa, L. N., Maia, M. A. G., Gruendl, R. A., Walker, A. R., Yanny, B., Drlica-Wagner, A., Benoit-Levy, A., Abbott, T. M. C., Allam, S. S., Annis, J., Bernstein, J. P., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Rosell, A. C., Cunha, C. E., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Estrada, J., Evrard, A. E., Neto, A. F., Finley, D. A., Flaugher, B., Frieman, J. A., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., March, M., Marshall, J. L., Miller, C., Miquel, R., Ogando, R., Peoples, J., Plazas, A., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Tucker, D. L., Wechsler, R., & Zuntz, J. The LMC geometry and outer stellar populations from early DES data. United States. doi:10.1093/mnras/stv356.
Balbinot, E., Santiago, B. X., Girardi, L., Pieres, A., da Costa, L. N., Maia, M. A. G., Gruendl, R. A., Walker, A. R., Yanny, B., Drlica-Wagner, A., Benoit-Levy, A., Abbott, T. M. C., Allam, S. S., Annis, J., Bernstein, J. P., Bernstein, R. A., Bertin, E., Brooks, D., Buckley-Geer, E., Rosell, A. C., Cunha, C. E., DePoy, D. L., Desai, S., Diehl, H. T., Doel, P., Estrada, J., Evrard, A. E., Neto, A. F., Finley, D. A., Flaugher, B., Frieman, J. A., Gruen, D., Honscheid, K., James, D., Kuehn, K., Kuropatkin, N., Lahav, O., March, M., Marshall, J. L., Miller, C., Miquel, R., Ogando, R., Peoples, J., Plazas, A., Scarpine, V., Schubnell, M., Sevilla-Noarbe, I., Smith, R. C., Soares-Santos, M., Suchyta, E., Swanson, M. E. C., Tarle, G., Tucker, D. L., Wechsler, R., and Zuntz, J. Sat . "The LMC geometry and outer stellar populations from early DES data". United States. doi:10.1093/mnras/stv356.
@article{osti_1342914,
title = {The LMC geometry and outer stellar populations from early DES data},
author = {Balbinot, E. and Santiago, B. X. and Girardi, L. and Pieres, A. and da Costa, L. N. and Maia, M. A. G. and Gruendl, R. A. and Walker, A. R. and Yanny, B. and Drlica-Wagner, A. and Benoit-Levy, A. and Abbott, T. M. C. and Allam, S. S. and Annis, J. and Bernstein, J. P. and Bernstein, R. A. and Bertin, E. and Brooks, D. and Buckley-Geer, E. and Rosell, A. C. and Cunha, C. E. and DePoy, D. L. and Desai, S. and Diehl, H. T. and Doel, P. and Estrada, J. and Evrard, A. E. and Neto, A. F. and Finley, D. A. and Flaugher, B. and Frieman, J. A. and Gruen, D. and Honscheid, K. and James, D. and Kuehn, K. and Kuropatkin, N. and Lahav, O. and March, M. and Marshall, J. L. and Miller, C. and Miquel, R. and Ogando, R. and Peoples, J. and Plazas, A. and Scarpine, V. and Schubnell, M. and Sevilla-Noarbe, I. and Smith, R. C. and Soares-Santos, M. and Suchyta, E. and Swanson, M. E. C. and Tarle, G. and Tucker, D. L. and Wechsler, R. and Zuntz, J.},
abstractNote = {The Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey (DES). The SV footprint covers a large portion of the outer Large Magellanic Cloud (LMC), providing photometry 1.5 mag fainter than the main sequence turn-off of the oldest LMC stellar population. We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = -38 degrees.14 +/- 0 degrees.08 (near side in the north) and a position angle for the line of nodes of theta(0) = 129 degrees.51 +/- 0 degrees.17. We find that stars younger than similar to 4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R->4Gyr = 1.41 +/- 0.01 kpc, while the younger population has R-<4Gyr = 0.72 +/- 0.01 kpc. However, the spatial distribution of the younger population deviates significantly from the projected exponential disc model. The distribution of old stars suggests a large truncation radius of R-t = 13.5 +/- 0.8 kpc. If this truncation is dominated by the tidal field of the Galaxy, we find that the LMC is similar or equal to 24(-6)(+9) times less massive than the encircled Galactic mass. By measuring the Red Clump peak magnitude and comparing with the best-fitting LMC disc model, we find that the LMC disc is warped and thicker in the outer regions north of the LMC centre. Our findings may either be interpreted as a warped and flared disc in the LMC outskirts, or as evidence of a spheroidal halo component.},
doi = {10.1093/mnras/stv356},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 1,
volume = 449,
place = {United States},
year = {Sat Mar 14 00:00:00 EDT 2015},
month = {Sat Mar 14 00:00:00 EDT 2015}
}