Detection of a population gradient in the Sagittarius stream

M. Bellazzini, H. J. Newberg, M. Correnti, F. R. Ferraro, L. Monaco

Resultado de la investigación: Article

39 Citas (Scopus)

Resumen

We present a quantitative comparison between the Horizontal Branch morphology in the core of the Sagittarius dwarf spheroidal galaxy (Sgr) and in a wide field sampling a portion of its tidal stream (Sgr Stream), located tens of kpc away from the center of the parent galaxy. We find that the Blue Horizontal Branch (BHB) stars in that part of the Stream are five times more abundant than in the Sgr core, relative to Red Clump stars. The difference in the ratio of BHB to RC stars between the two fields is significant at the ≳4.8σ level. This indicates that the old and metal-poor population of Sgr was preferentially stripped from the galaxy in past peri-Galactic passages with respect to the intermediate-age metal rich population that presently dominates the bound core of Sgr, probably due to a strong radial gradient that was settled within the galaxy before its disruption. The technique adopted in the present study allows to trace population gradients along the whole extension of the Stream.

Idioma originalEnglish
PublicaciónAstronomy and Astrophysics
Volumen457
N.º2
DOI
EstadoPublished - oct 2006

Huella dactilar

gradients
galaxies
horizontal branch stars
blue stars
stars
metal
clumps
dwarf galaxies
metals
sampling
detection
comparison

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Bellazzini, M. ; Newberg, H. J. ; Correnti, M. ; Ferraro, F. R. ; Monaco, L. / Detection of a population gradient in the Sagittarius stream. En: Astronomy and Astrophysics. 2006 ; Vol. 457, N.º 2.
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abstract = "We present a quantitative comparison between the Horizontal Branch morphology in the core of the Sagittarius dwarf spheroidal galaxy (Sgr) and in a wide field sampling a portion of its tidal stream (Sgr Stream), located tens of kpc away from the center of the parent galaxy. We find that the Blue Horizontal Branch (BHB) stars in that part of the Stream are five times more abundant than in the Sgr core, relative to Red Clump stars. The difference in the ratio of BHB to RC stars between the two fields is significant at the ≳4.8σ level. This indicates that the old and metal-poor population of Sgr was preferentially stripped from the galaxy in past peri-Galactic passages with respect to the intermediate-age metal rich population that presently dominates the bound core of Sgr, probably due to a strong radial gradient that was settled within the galaxy before its disruption. The technique adopted in the present study allows to trace population gradients along the whole extension of the Stream.",
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Detection of a population gradient in the Sagittarius stream. / Bellazzini, M.; Newberg, H. J.; Correnti, M.; Ferraro, F. R.; Monaco, L.

En: Astronomy and Astrophysics, Vol. 457, N.º 2, 10.2006.

Resultado de la investigación: Article

TY - JOUR

T1 - Detection of a population gradient in the Sagittarius stream

AU - Bellazzini, M.

AU - Newberg, H. J.

AU - Correnti, M.

AU - Ferraro, F. R.

AU - Monaco, L.

PY - 2006/10

Y1 - 2006/10

N2 - We present a quantitative comparison between the Horizontal Branch morphology in the core of the Sagittarius dwarf spheroidal galaxy (Sgr) and in a wide field sampling a portion of its tidal stream (Sgr Stream), located tens of kpc away from the center of the parent galaxy. We find that the Blue Horizontal Branch (BHB) stars in that part of the Stream are five times more abundant than in the Sgr core, relative to Red Clump stars. The difference in the ratio of BHB to RC stars between the two fields is significant at the ≳4.8σ level. This indicates that the old and metal-poor population of Sgr was preferentially stripped from the galaxy in past peri-Galactic passages with respect to the intermediate-age metal rich population that presently dominates the bound core of Sgr, probably due to a strong radial gradient that was settled within the galaxy before its disruption. The technique adopted in the present study allows to trace population gradients along the whole extension of the Stream.

AB - We present a quantitative comparison between the Horizontal Branch morphology in the core of the Sagittarius dwarf spheroidal galaxy (Sgr) and in a wide field sampling a portion of its tidal stream (Sgr Stream), located tens of kpc away from the center of the parent galaxy. We find that the Blue Horizontal Branch (BHB) stars in that part of the Stream are five times more abundant than in the Sgr core, relative to Red Clump stars. The difference in the ratio of BHB to RC stars between the two fields is significant at the ≳4.8σ level. This indicates that the old and metal-poor population of Sgr was preferentially stripped from the galaxy in past peri-Galactic passages with respect to the intermediate-age metal rich population that presently dominates the bound core of Sgr, probably due to a strong radial gradient that was settled within the galaxy before its disruption. The technique adopted in the present study allows to trace population gradients along the whole extension of the Stream.

KW - Galaxies: dwarf

KW - Galaxies: evolution

KW - Stars: horizontal-branch

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U2 - 10.1051/0004-6361:20066002

DO - 10.1051/0004-6361:20066002

M3 - Article

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JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

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