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Title: THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE

Abstract

We present three-dimensional space velocities of stars selected to be consistent with membership in the Virgo stellar substructure. Candidates were selected from SA 103, a single 40' Multiplication-Sign 40' field from our proper-motion (PM) survey in Kapteyn's Selected Areas (SAs), based on the PMs, Sloan Digital Sky Survey (SDSS) photometry, and follow-up spectroscopy of 215 stars. The signature of the Virgo substructure is clear in the SDSS color-magnitude diagram (CMD) centered on SA 103, and 16 stars are identified that have high Galactocentric-frame radial velocities (V{sub GSR} > 50 km s{sup -1}) and lie near the CMD locus of Virgo. The implied distance to the Virgo substructure from the candidates is 14 {+-} 3 kpc. We derive mean kinematics from these 16 stars, finding a radial velocity V{sub GSR} = 153 {+-} 22 km s{sup -1} and proper motions ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}) = (- 5.24, -0.91) {+-} (0.43, 0.46) mas yr{sup -1}. From the mean kinematics of these members, we determine that the Virgo progenitor was on an eccentric (e {approx} 0.8) orbit that recently passed near the Galactic center (pericentric distance R{sub p} {approx} 6 kpc). This destructive orbit is consistent with the idea that the substructure(s)more » in Virgo originated in the tidal disruption of a Milky Way satellite. N-body simulations suggest that the entire cloud-like Virgo substructure (encompassing the 'Virgo Overdensity' and the 'Virgo Stellar Stream') is likely the tidal debris remnant from a recently disrupted massive ({approx}10{sup 9} M{sub Sun }) dwarf galaxy. The model also suggests that some other known stellar overdensities in the Milky Way halo (e.g., the Pisces Overdensity and debris near NGC 2419 and SEGUE 1) are explained by the disruption of the Virgo progenitor.« less

Authors:
; ; ;  [1]; ;  [2]
  1. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180 (United States)
  2. Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)
Publication Date:
OSTI Identifier:
22039391
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 753; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COLOR; COMPUTERIZED SIMULATION; DIAGRAMS; DISTANCE; MILKY WAY; ORBITS; PHOTOMETRY; PROPER MOTION; RADIAL VELOCITY; SPECTROSCOPY; STARS; THREE-DIMENSIONAL CALCULATIONS

Citation Formats

Carlin, Jeffrey L, Yam, William, Willett, Benjamin A, Newberg, Heidi J, Casetti-Dinescu, Dana I, Girard, Terrence M, and Majewski, Steven R., E-mail: carlij@rpi.edu. THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE. United States: N. p., 2012. Web. doi:10.1088/0004-637X/753/2/145.
Carlin, Jeffrey L, Yam, William, Willett, Benjamin A, Newberg, Heidi J, Casetti-Dinescu, Dana I, Girard, Terrence M, & Majewski, Steven R., E-mail: carlij@rpi.edu. THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE. United States. https://doi.org/10.1088/0004-637X/753/2/145
Carlin, Jeffrey L, Yam, William, Willett, Benjamin A, Newberg, Heidi J, Casetti-Dinescu, Dana I, Girard, Terrence M, and Majewski, Steven R., E-mail: carlij@rpi.edu. 2012. "THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE". United States. https://doi.org/10.1088/0004-637X/753/2/145.
@article{osti_22039391,
title = {THE ORIGIN OF THE VIRGO STELLAR SUBSTRUCTURE},
author = {Carlin, Jeffrey L and Yam, William and Willett, Benjamin A and Newberg, Heidi J and Casetti-Dinescu, Dana I and Girard, Terrence M and Majewski, Steven R., E-mail: carlij@rpi.edu},
abstractNote = {We present three-dimensional space velocities of stars selected to be consistent with membership in the Virgo stellar substructure. Candidates were selected from SA 103, a single 40' Multiplication-Sign 40' field from our proper-motion (PM) survey in Kapteyn's Selected Areas (SAs), based on the PMs, Sloan Digital Sky Survey (SDSS) photometry, and follow-up spectroscopy of 215 stars. The signature of the Virgo substructure is clear in the SDSS color-magnitude diagram (CMD) centered on SA 103, and 16 stars are identified that have high Galactocentric-frame radial velocities (V{sub GSR} > 50 km s{sup -1}) and lie near the CMD locus of Virgo. The implied distance to the Virgo substructure from the candidates is 14 {+-} 3 kpc. We derive mean kinematics from these 16 stars, finding a radial velocity V{sub GSR} = 153 {+-} 22 km s{sup -1} and proper motions ({mu}{sub {alpha}}cos {delta}, {mu}{sub {delta}}) = (- 5.24, -0.91) {+-} (0.43, 0.46) mas yr{sup -1}. From the mean kinematics of these members, we determine that the Virgo progenitor was on an eccentric (e {approx} 0.8) orbit that recently passed near the Galactic center (pericentric distance R{sub p} {approx} 6 kpc). This destructive orbit is consistent with the idea that the substructure(s) in Virgo originated in the tidal disruption of a Milky Way satellite. N-body simulations suggest that the entire cloud-like Virgo substructure (encompassing the 'Virgo Overdensity' and the 'Virgo Stellar Stream') is likely the tidal debris remnant from a recently disrupted massive ({approx}10{sup 9} M{sub Sun }) dwarf galaxy. The model also suggests that some other known stellar overdensities in the Milky Way halo (e.g., the Pisces Overdensity and debris near NGC 2419 and SEGUE 1) are explained by the disruption of the Virgo progenitor.},
doi = {10.1088/0004-637X/753/2/145},
url = {https://www.osti.gov/biblio/22039391}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 753,
place = {United States},
year = {Tue Jul 10 00:00:00 EDT 2012},
month = {Tue Jul 10 00:00:00 EDT 2012}
}