Discovery of new globular clusters in the Sagittarius dwarf galaxy

D. Minniti; V. Ripepi; J. G. Fernández-Trincado; J. Alonso-García; L. C. Smith; P. W. Lucas; M. Gómez; J. B. Pullen; E. R. Garro; F. Vivanco Cádiz; M. Hempel; M. Rejkuba; R. K. Saito; T. Palma; J. J. Clariá; M. Gregg; D. Majaess

doi:10.1051/0004-6361/202140395

Discovery of new globular clusters in the Sagittarius dwarf galaxy

D. Minniti, V. Ripepi, J. G. Fernández-Trincado, J. Alonso-García, L. C. Smith, P. W. Lucas, M. Gómez, J. B. Pullen, E. R. Garro, F. Vivanco Cádiz, M. Hempel, M. Rejkuba, R. K. Saito, T. Palma, J. J. Clariá, M. Gregg, D. Majaess

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Abstract

Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.

Original language	English
Article number	L4
Number of pages	12
Journal	Astronomy & Astrophysics
Volume	647
Early online date	12 Mar 2021
DOIs	https://doi.org/10.1051/0004-6361/202140395
Publication status	E-pub ahead of print - 12 Mar 2021

Keywords

Galaxies: dwarf
Galaxies: star clusters: general
Globular clusters: general
Stars: variables: RR Lyrae

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© ESO 2021. Published by EDP EDP Sciences. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1051/0004-6361/202140395
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Minniti, D., Ripepi, V., Fernández-Trincado, J. G., Alonso-García, J., Smith, L. C., Lucas, P. W., Gómez, M., Pullen, J. B., Garro, E. R., Cádiz, F. V., Hempel, M., Rejkuba, M., Saito, R. K., Palma, T., Clariá, J. J., Gregg, M., & Majaess, D. (2021). Discovery of new globular clusters in the Sagittarius dwarf galaxy. Astronomy & Astrophysics, 647, Article L4. Advance online publication. https://doi.org/10.1051/0004-6361/202140395

@article{e9f53e231f134e4a91bf5710b39dc898,

title = "Discovery of new globular clusters in the Sagittarius dwarf galaxy",

abstract = "Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.",

keywords = "Galaxies: dwarf, Galaxies: star clusters: general, Globular clusters: general, Stars: variables: RR Lyrae",

author = "D. Minniti and V. Ripepi and Fern{\'a}ndez-Trincado, {J. G.} and J. Alonso-Garc{\'i}a and Smith, {L. C.} and Lucas, {P. W.} and M. G{\'o}mez and Pullen, {J. B.} and Garro, {E. R.} and C{\'a}diz, {F. Vivanco} and M. Hempel and M. Rejkuba and Saito, {R. K.} and T. Palma and Clari{\'a}, {J. J.} and M. Gregg and D. Majaess",

note = "{\textcopyright} ESO 2021. Published by EDP Sciences. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1051/0004-6361/202140395",

year = "2021",

month = mar,

day = "12",

doi = "10.1051/0004-6361/202140395",

language = "English",

volume = "647",

journal = "Astronomy & Astrophysics",

issn = "0004-6361",

publisher = "EDP Sciences",

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Minniti, D, Ripepi, V, Fernández-Trincado, JG, Alonso-García, J, Smith, LC, Lucas, PW, Gómez, M, Pullen, JB, Garro, ER, Cádiz, FV, Hempel, M, Rejkuba, M, Saito, RK, Palma, T, Clariá, JJ, Gregg, M & Majaess, D 2021, 'Discovery of new globular clusters in the Sagittarius dwarf galaxy', Astronomy & Astrophysics, vol. 647, L4. https://doi.org/10.1051/0004-6361/202140395

TY - JOUR

T1 - Discovery of new globular clusters in the Sagittarius dwarf galaxy

AU - Minniti, D.

AU - Ripepi, V.

AU - Fernández-Trincado, J. G.

AU - Alonso-García, J.

AU - Smith, L. C.

AU - Lucas, P. W.

AU - Gómez, M.

AU - Pullen, J. B.

AU - Garro, E. R.

AU - Cádiz, F. Vivanco

AU - Hempel, M.

AU - Rejkuba, M.

AU - Saito, R. K.

AU - Palma, T.

AU - Clariá, J. J.

AU - Gregg, M.

AU - Majaess, D.

N1 - © ESO 2021. Published by EDP Sciences. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1051/0004-6361/202140395

PY - 2021/3/12

Y1 - 2021/3/12

N2 - Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.

AB - Context. Globular clusters (GCs) are witnesses of the past accretion events onto the Milky Way. In particular, the GCs of the Sagittarius (Sgr) dwarf galaxy are important probes of an on-going merger. Aims. Our main goal is to search for new GC members of this dwarf galaxy using the VISTA Variables in the Via Lactea Extended Survey (VVVX) near-infrared database combined with the Gaia Early Data Release 3 (EDR3) optical database. Methods. We investigated all VVVX-enabled discoveries of GC candidates in a region covering about 180 sq. deg. toward the bulge and the Sgr dwarf galaxy. We used multiband point-spread function photometry to obtain deep color-magnitude diagrams (CMDs) and luminosity functions (LFs) for all GC candidates, complemented by accurate Gaia-EDR3 proper motions (PMs) to select Sgr members and variability information to select RR Lyrae which are potential GC members. Results. After applying a strict PM cut to discard foreground bulge and disk stars, the CMDs and LFs for some of the GC candidates exhibit well defined red giant branches and red clump giant star peaks. We selected the best Sgr GCs, estimating their distances, reddenings, and associated RR Lyrae. Conclusions. We discover 12 new Sgr GC members, more than doubling the number of GCs known in this dwarf galaxy. In addition, there are 11 other GC candidates identified that are uncertain, awaiting better data for confirmation.

KW - Galaxies: dwarf

KW - Galaxies: star clusters: general

KW - Globular clusters: general

KW - Stars: variables: RR Lyrae

UR - http://www.scopus.com/inward/record.url?scp=85102551412&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/202140395

DO - 10.1051/0004-6361/202140395

M3 - Article

SN - 0004-6361

VL - 647

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - L4

ER -

Discovery of new globular clusters in the Sagittarius dwarf galaxy

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Keywords

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