A Sequoia in the Garden

FSR 1758 - Dwarf Galaxy or Giant Globular Cluster?

Rodolfo H. Barbá, Dante Minniti, Douglas Geisler, Javier Alonso-García, Maren Hempel, Antonela Monachesi, Julia I. Arias, Facundo A. Gómez

Resultado de la investigación: Article

1 Cita (Scopus)

Resumen

We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in the Galactic Bulge. The combination of optical data from the 2nd Gaia Data Release and the DECam Plane Survey and near-IR data from the VISTA Variables in the Vía Láctea Extended Survey led to a clean sample of likely members. Based on this integrated data set, position, distance, reddening, size, metallicity, absolute magnitude, and proper motion (PM) of this object are measured. We estimate the following parameters: α = 17:31:12, δ = -39:48:30 (J2000), D = 11.5 ±1.0 kpc, mag, R c = 10 pc, R t = 150 pc, dex, Mi < -8.6 ±1.0, μ α = -2.85 mas yr-1, and μ δ = 2.55 mas yr-1. The nature of this object is discussed. If FRS 1758 is a genuine globular cluster (GC), it is one of the largest in the Milky Way, with a size comparable or even larger than that of ω Cen, being also an extreme outlier in the size versus Galactocentric distance diagram. The presence of a concentration of long-period RR Lyrae variable stars and blue horizontal branch stars suggests that it is a typical metal-poor GC of Oosterhoff type II. Further exploration of a larger surrounding field reveals common PM stars, suggesting either tidal debris or that FRS 1758 is actually the central part of a larger extended structure such as a new dwarf galaxy, tentatively named Scorpius. In either case, this object is remarkable, and its discovery graphically illustrates the possibility of finding other large objects hidden in the Galactic Bulge using future surveys.

Idioma originalEnglish
Número de artículoL24
PublicaciónAstrophysical Journal Letters
Volumen870
N.º2
DOI
EstadoPublished - 10 ene 2019

Huella dactilar

dwarf galaxies
globular clusters
garden
galactic bulge
proper motion
horizontal branch stars
blue stars
variable stars
outlier
debris
metallicity
diagram
diagrams
stars
metal
estimates
metals

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Citar esto

Barbá, R. H., Minniti, D., Geisler, D., Alonso-García, J., Hempel, M., Monachesi, A., ... Gómez, F. A. (2019). A Sequoia in the Garden: FSR 1758 - Dwarf Galaxy or Giant Globular Cluster? Astrophysical Journal Letters, 870(2), [L24]. https://doi.org/10.3847/2041-8213/aaf811
Barbá, Rodolfo H. ; Minniti, Dante ; Geisler, Douglas ; Alonso-García, Javier ; Hempel, Maren ; Monachesi, Antonela ; Arias, Julia I. ; Gómez, Facundo A. / A Sequoia in the Garden : FSR 1758 - Dwarf Galaxy or Giant Globular Cluster?. En: Astrophysical Journal Letters. 2019 ; Vol. 870, N.º 2.
@article{039649127c63421d84f21b6f82845209,
title = "A Sequoia in the Garden: FSR 1758 - Dwarf Galaxy or Giant Globular Cluster?",
abstract = "We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in the Galactic Bulge. The combination of optical data from the 2nd Gaia Data Release and the DECam Plane Survey and near-IR data from the VISTA Variables in the V{\'i}a L{\'a}ctea Extended Survey led to a clean sample of likely members. Based on this integrated data set, position, distance, reddening, size, metallicity, absolute magnitude, and proper motion (PM) of this object are measured. We estimate the following parameters: α = 17:31:12, δ = -39:48:30 (J2000), D = 11.5 ±1.0 kpc, mag, R c = 10 pc, R t = 150 pc, dex, Mi < -8.6 ±1.0, μ α = -2.85 mas yr-1, and μ δ = 2.55 mas yr-1. The nature of this object is discussed. If FRS 1758 is a genuine globular cluster (GC), it is one of the largest in the Milky Way, with a size comparable or even larger than that of ω Cen, being also an extreme outlier in the size versus Galactocentric distance diagram. The presence of a concentration of long-period RR Lyrae variable stars and blue horizontal branch stars suggests that it is a typical metal-poor GC of Oosterhoff type II. Further exploration of a larger surrounding field reveals common PM stars, suggesting either tidal debris or that FRS 1758 is actually the central part of a larger extended structure such as a new dwarf galaxy, tentatively named Scorpius. In either case, this object is remarkable, and its discovery graphically illustrates the possibility of finding other large objects hidden in the Galactic Bulge using future surveys.",
keywords = "Galaxy: bulge, Galaxy: stellar content, globular clusters: individual (FSR 1758), stars: kinematics and dynamics",
author = "Barb{\'a}, {Rodolfo H.} and Dante Minniti and Douglas Geisler and Javier Alonso-Garc{\'i}a and Maren Hempel and Antonela Monachesi and Arias, {Julia I.} and G{\'o}mez, {Facundo A.}",
year = "2019",
month = "1",
day = "10",
doi = "10.3847/2041-8213/aaf811",
language = "English",
volume = "870",
journal = "Astrophysical Journal Letters",
issn = "2041-8205",
publisher = "IOP Publishing Ltd.",
number = "2",

}

Barbá, RH, Minniti, D, Geisler, D, Alonso-García, J, Hempel, M, Monachesi, A, Arias, JI & Gómez, FA 2019, 'A Sequoia in the Garden: FSR 1758 - Dwarf Galaxy or Giant Globular Cluster?', Astrophysical Journal Letters, vol. 870, n.º 2, L24. https://doi.org/10.3847/2041-8213/aaf811

A Sequoia in the Garden : FSR 1758 - Dwarf Galaxy or Giant Globular Cluster? / Barbá, Rodolfo H.; Minniti, Dante; Geisler, Douglas; Alonso-García, Javier; Hempel, Maren; Monachesi, Antonela; Arias, Julia I.; Gómez, Facundo A.

En: Astrophysical Journal Letters, Vol. 870, N.º 2, L24, 10.01.2019.

Resultado de la investigación: Article

TY - JOUR

T1 - A Sequoia in the Garden

T2 - FSR 1758 - Dwarf Galaxy or Giant Globular Cluster?

AU - Barbá, Rodolfo H.

AU - Minniti, Dante

AU - Geisler, Douglas

AU - Alonso-García, Javier

AU - Hempel, Maren

AU - Monachesi, Antonela

AU - Arias, Julia I.

AU - Gómez, Facundo A.

PY - 2019/1/10

Y1 - 2019/1/10

N2 - We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in the Galactic Bulge. The combination of optical data from the 2nd Gaia Data Release and the DECam Plane Survey and near-IR data from the VISTA Variables in the Vía Láctea Extended Survey led to a clean sample of likely members. Based on this integrated data set, position, distance, reddening, size, metallicity, absolute magnitude, and proper motion (PM) of this object are measured. We estimate the following parameters: α = 17:31:12, δ = -39:48:30 (J2000), D = 11.5 ±1.0 kpc, mag, R c = 10 pc, R t = 150 pc, dex, Mi < -8.6 ±1.0, μ α = -2.85 mas yr-1, and μ δ = 2.55 mas yr-1. The nature of this object is discussed. If FRS 1758 is a genuine globular cluster (GC), it is one of the largest in the Milky Way, with a size comparable or even larger than that of ω Cen, being also an extreme outlier in the size versus Galactocentric distance diagram. The presence of a concentration of long-period RR Lyrae variable stars and blue horizontal branch stars suggests that it is a typical metal-poor GC of Oosterhoff type II. Further exploration of a larger surrounding field reveals common PM stars, suggesting either tidal debris or that FRS 1758 is actually the central part of a larger extended structure such as a new dwarf galaxy, tentatively named Scorpius. In either case, this object is remarkable, and its discovery graphically illustrates the possibility of finding other large objects hidden in the Galactic Bulge using future surveys.

AB - We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in the Galactic Bulge. The combination of optical data from the 2nd Gaia Data Release and the DECam Plane Survey and near-IR data from the VISTA Variables in the Vía Láctea Extended Survey led to a clean sample of likely members. Based on this integrated data set, position, distance, reddening, size, metallicity, absolute magnitude, and proper motion (PM) of this object are measured. We estimate the following parameters: α = 17:31:12, δ = -39:48:30 (J2000), D = 11.5 ±1.0 kpc, mag, R c = 10 pc, R t = 150 pc, dex, Mi < -8.6 ±1.0, μ α = -2.85 mas yr-1, and μ δ = 2.55 mas yr-1. The nature of this object is discussed. If FRS 1758 is a genuine globular cluster (GC), it is one of the largest in the Milky Way, with a size comparable or even larger than that of ω Cen, being also an extreme outlier in the size versus Galactocentric distance diagram. The presence of a concentration of long-period RR Lyrae variable stars and blue horizontal branch stars suggests that it is a typical metal-poor GC of Oosterhoff type II. Further exploration of a larger surrounding field reveals common PM stars, suggesting either tidal debris or that FRS 1758 is actually the central part of a larger extended structure such as a new dwarf galaxy, tentatively named Scorpius. In either case, this object is remarkable, and its discovery graphically illustrates the possibility of finding other large objects hidden in the Galactic Bulge using future surveys.

KW - Galaxy: bulge

KW - Galaxy: stellar content

KW - globular clusters: individual (FSR 1758)

KW - stars: kinematics and dynamics

UR - http://www.scopus.com/inward/record.url?scp=85060253473&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/aaf811

DO - 10.3847/2041-8213/aaf811

M3 - Article

VL - 870

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

SN - 2041-8205

IS - 2

M1 - L24

ER -