skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL

Abstract

A vertical X-shaped structure in the Galactic bulge was recently reported. Here, we present evidence of a similar X-shaped structure in the Shen et al. 2010 bar/boxy bulge model that simultaneously matches the stellar kinematics successfully. The X-shaped structure is found in the central region of our bar/boxy bulge model and is qualitatively consistent with the observed one in many aspects. End-to-end separations of the X-shaped structure in the radial and vertical directions are roughly 3 kpc and 1.8 kpc, respectively. The X-shaped structure contains about 7% of light in the boxy bulge region, but it is significant enough to be identified in observations. An X-shaped structure naturally arises in the formation of bar/boxy bulges and is mainly associated with orbits trapped around the vertically extended x{sub 1} family. Like the bar in our model, the X-shaped structure tilts away from the Sun-Galactic center line by 20 Degree-Sign . The X-shaped structure becomes increasingly symmetric about the disk plane, so the observed symmetry may indicate that it formed at least a few billion years ago. The existence of the vertical X-shaped structure suggests that the formation of the Milky Way bulge is shaped mainly by internal disk dynamical instabilities.

Authors:
Publication Date:
OSTI Identifier:
22078540
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 757; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; INSTABILITY; MATHEMATICAL MODELS; MILKY WAY; ORBITS; SUN; SYMMETRY; VISIBLE RADIATION

Citation Formats

Zhaoyu, Li, and Shen Juntai, E-mail: jshen@shao.ac.cn. THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL. United States: N. p., 2012. Web. doi:10.1088/2041-8205/757/1/L7.
Zhaoyu, Li, & Shen Juntai, E-mail: jshen@shao.ac.cn. THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL. United States. https://doi.org/10.1088/2041-8205/757/1/L7
Zhaoyu, Li, and Shen Juntai, E-mail: jshen@shao.ac.cn. 2012. "THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL". United States. https://doi.org/10.1088/2041-8205/757/1/L7.
@article{osti_22078540,
title = {THE VERTICAL X-SHAPED STRUCTURE IN THE MILKY WAY: EVIDENCE FROM A SIMPLE BOXY BULGE MODEL},
author = {Zhaoyu, Li and Shen Juntai, E-mail: jshen@shao.ac.cn},
abstractNote = {A vertical X-shaped structure in the Galactic bulge was recently reported. Here, we present evidence of a similar X-shaped structure in the Shen et al. 2010 bar/boxy bulge model that simultaneously matches the stellar kinematics successfully. The X-shaped structure is found in the central region of our bar/boxy bulge model and is qualitatively consistent with the observed one in many aspects. End-to-end separations of the X-shaped structure in the radial and vertical directions are roughly 3 kpc and 1.8 kpc, respectively. The X-shaped structure contains about 7% of light in the boxy bulge region, but it is significant enough to be identified in observations. An X-shaped structure naturally arises in the formation of bar/boxy bulges and is mainly associated with orbits trapped around the vertically extended x{sub 1} family. Like the bar in our model, the X-shaped structure tilts away from the Sun-Galactic center line by 20 Degree-Sign . The X-shaped structure becomes increasingly symmetric about the disk plane, so the observed symmetry may indicate that it formed at least a few billion years ago. The existence of the vertical X-shaped structure suggests that the formation of the Milky Way bulge is shaped mainly by internal disk dynamical instabilities.},
doi = {10.1088/2041-8205/757/1/L7},
url = {https://www.osti.gov/biblio/22078540}, journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 757,
place = {United States},
year = {Thu Sep 20 00:00:00 EDT 2012},
month = {Thu Sep 20 00:00:00 EDT 2012}
}