Abstract:
Context. Ultra-compact dwarfs (UCDs) are stellar systems displaying colours and metallicities between those of globular clusters (GCs) and early-type dwarf galaxies, as well as sizes of Reff 100 pc and luminosities in the range-13.5 <MV<-11 mag. Although their origin is still subject of debate, the most popular scenarios suggest that they are massive star clusters or the nuclei of tidally stripped dwarf galaxies. Aims. NGC 5044 is the central massive elliptical galaxy of the NGC 5044 group. Its GC/UCD system is completely unexplored. Methods. In Gemini+GMOS deep images of several fields around NGC 5044 and in spectroscopic multi-object data of one of these fields, we detected an unresolved source with g′ ∼ 20.6 mag, compatible with being an UCD. Its radial velocity was obtained with FXCOR and the penalized pixel-fitting (pPXF) code. To study its stellar population content, we measured the Lick/IDS indices and compared them with predictions of single stellar population models, and we used the full spectral fitting technique. Results. The spectroscopic analysis of the UCD revealed a radial velocity that agrees with the velocity of the elliptical galaxy NGC 5044. From the Lick/IDS indices, we have obtained a luminosity-weighted age and metallicity of 11.7+ 1.4 -1.2 Gyr and [Z/H] =-0.79 ± 0.04 dex, respectively, as well as [α/Fe] = 0.30 ± 0.06. From the full spectral fitting technique, we measured a lower age (8.52 Gyr) and a similar total metallicity ([Z/H] =-0.86 dex). Conclusions. Our results indicate that NGC 5044-UCD1 is most likely an extreme GC (MV ∼-12.5 mag) belonging to the GC system of the elliptical galaxy NGC 5044. © 2017 ESO.
Registro:
Documento: |
Artículo
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Título: | First confirmed ultra-compact dwarf galaxy in the NGC 5044 group |
Autor: | Faifer, F.R.; Escudero, C.G.; Scalia, M.C.; Castelli, A.V.S.; Norris, M.; De Rossi, M.E.; Forte, J.C.; Cellone, S.A. |
Filiación: | Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de la Plata, Paseo del Bosque s/n, La Plata, B1900FWA, Argentina Instituto de Astrofísica de la Plata (CCT la Plata-CONICET-UNLP), Paseo del Bosque s/n, La Plata, B1900FWA, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas, Godoy Cruz 2290C1425FQB, Argentina Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE, United Kingdom Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales y Ciclo Básico Común, Buenos Aires, Argentina CONICET-Universidad de Buenos Aires, Instituto de Astronomía y Física Del Espacio (IAFE), Argentina Planetario Galileo Galilei, Secretaría de Cultura, Av. Sarmiento S/N, Ciudad Autónoma de Buenos Aires, 1425, Argentina
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Palabras clave: | Galaxies: elliptical and lenticular, cD; Galaxies: photometry; Galaxies: star clusters: general; Astrophysics; Luminance; Spectroscopic analysis; Stars; Elliptical galaxies; Galaxies: elliptical and lenticular , CD; Galaxies: photometry; Galaxies: star clusters: generals; Globular clusters; Radial velocity; Spectral fitting; Stellar populations; Galaxies |
Año: | 2017
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Volumen: | 599
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DOI: |
http://dx.doi.org/10.1051/0004-6361/201730493 |
Título revista: | Astronomy and Astrophysics
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Título revista abreviado: | Astron. Astrophys.
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ISSN: | 00046361
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CODEN: | AAEJA
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Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046361_v599_n_p_Faifer |
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Citas:
---------- APA ----------
Faifer, F.R., Escudero, C.G., Scalia, M.C., Castelli, A.V.S., Norris, M., De Rossi, M.E., Forte, J.C.,..., Cellone, S.A.
(2017)
. First confirmed ultra-compact dwarf galaxy in the NGC 5044 group. Astronomy and Astrophysics, 599.
http://dx.doi.org/10.1051/0004-6361/201730493---------- CHICAGO ----------
Faifer, F.R., Escudero, C.G., Scalia, M.C., Castelli, A.V.S., Norris, M., De Rossi, M.E., et al.
"First confirmed ultra-compact dwarf galaxy in the NGC 5044 group"
. Astronomy and Astrophysics 599
(2017).
http://dx.doi.org/10.1051/0004-6361/201730493---------- MLA ----------
Faifer, F.R., Escudero, C.G., Scalia, M.C., Castelli, A.V.S., Norris, M., De Rossi, M.E., et al.
"First confirmed ultra-compact dwarf galaxy in the NGC 5044 group"
. Astronomy and Astrophysics, vol. 599, 2017.
http://dx.doi.org/10.1051/0004-6361/201730493---------- VANCOUVER ----------
Faifer, F.R., Escudero, C.G., Scalia, M.C., Castelli, A.V.S., Norris, M., De Rossi, M.E., et al. First confirmed ultra-compact dwarf galaxy in the NGC 5044 group. Astron. Astrophys. 2017;599.
http://dx.doi.org/10.1051/0004-6361/201730493