Stellar density profile and mass of the Milky Way bulge from VVV data

Valenti, E.; Zoccali, M.; Gonzalez, O. A.; Minniti, D.; Alonso-García, J.; Marchetti, Enrico; Hempel, M.; Renzini, A.; Rejkuba, M.

doi:10.1051/0004-6361/201527500

Cited by 103 publications

(128 citation statements)

References 32 publications

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“…In this case, the σ peak in the Milky Way bulge would be limited to Galactic latitudes |b| < 2 (∼0.28 kpc). This is also in good agreement with the conclusions of Valenti et al (2016), where the high stellar density peak of the central Milky Way bulge closely follows a more axisymmetric σ peak than that presented in the GIBS velocity dispersion maps.…”

Section: Comparison Of the Bulge Of Ngc 4710 And The Milky Waysupporting

confidence: 91%

Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE

Gonzalez

Gadotti

Debattista

et al. 2016

A&A

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Context. Our view of the structure of the Milky Way and, in particular, its bulge is obscured by the intervening stars, dust, and gas in the disc. While great progress in understanding the bulge has been achieved with past and ongoing observations, the comparison of its global chemodynamical properties with respect to those of bulges seen in external galaxies has yet to be accomplished. Aims. We used the Multi Unit Spectroscopic Explorer (MUSE) instrument installed on the Very Large Telescope (VLT) to obtain spectral and imaging coverage of NGC 4710. The wide area and excellent sampling of the MUSE integral field spectrograph allows us to investigate the dynamical properties of the X-shaped bulge of NGC 4710 and compare it with the properties of the X-shaped bulge of the Milky Way. Methods. We measured the radial velocities, velocity dispersion, and stellar populations using a penalised pixel full spectral fitting technique adopting simple stellar populations models, on a 1 × 1 area centred on the bulge of NGC 4710. We constructed the velocity maps of the bulge of NGC 4710 and investigated the presence of vertical metallicity gradients. These properties were compared to those of the Milky Way bulge and to a simulated galaxy with a boxy-peanut bulge. Results. We find the line-of-sight velocity maps and 1D rotation curves of the bulge of NGC 4710 to be remarkably similar to those of the Milky Way bulge. Some specific differences that were identified are in good agreement with the expectations from variations in the bar orientation angle. The bulge of NGC 4710 has a boxy-peanut morphology with a pronounced X-shape, showing no indication of any additional spheroidally distributed bulge population, in which we measure a vertical metallicity gradient of 0.35 dex/kpc. Conclusions. The general properties of NGC 4710 are very similar to those observed in the Milky Way bulge. However, it has been suggested that the Milky Way bulge has an additional component that is comprised of the oldest, most metal-poor stars, which is not part of the boxy-peanut bulge structure. Such a population is not observed in NGC 4710, but could be hidden in the integrated light we observed.

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Section: Comparison Of the Bulge Of Ngc 4710 And The Milky Waysupporting

confidence: 91%

Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE

Gonzalez

Gadotti

Debattista

et al. 2016

A&A

Self Cite

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“…For M33, MW and M31, they used M bulge /10 10 M = 0, 2.2, and 4, respectively. We also adopt the same values as they are in agreement with more recent studies (Seigar 2011;Kam et al 2015;Valenti et al 2016;Blaña Díaz et al 2017). We note again that the correlation in K10 takes into account only the satellites with L V > 2 × 10 5 L , hence it should not be influenced by the recent discoveries of fainter satellites.…”

Section: The Main Samplesupporting

confidence: 54%

The Number of Dwarf Satellites of Disk Galaxies versus their Bulge Mass in the Standard Model of Cosmology

Raouf

Khosroshahi

Tavasoli

et al. 2019

ApJ

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There is a correlation between bulge mass of the three main galaxies of the Local Group (LG), i.e. M31, Milky Way (MW), and M33, and the number of their dwarf spheroidal galaxies. A similar correlation has also been reported for spiral galaxies with comparable luminosities outside the LG. These correlations do not appear to be expected in standard hierarchical galaxy formation. In this contribution, and for the first time, we present a quantitative investigation of the expectations of the standard model of cosmology for this possible relation using a galaxy catalogue based on the Millennium-II simulation. Our main sample consists of disk galaxies at the centers of halos with a range of virial masses similar to M33, MW, and M31. For this sample, we find an average trend (though with very large scatter) similar to the one observed in the LG; disk galaxies in heavier halos on average host heavier bulges and larger number of satellites. In addition, we study sub-samples of disk galaxies with very similar stellar or halo masses (but spanning a range of 2-3 orders of magnitude in bulge mass) and find no obvious trend in the number of satellites vs. bulge mass. We conclude that while for a wide galaxy mass range a relation arises (which seems to be a manifestation of the satellite number -halo mass correlation), for a narrow one there is no relation between number of satellites and bulge mass in the standard model. Further studies are needed to better understand the expectations of the standard model for this possible relation.

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“…Indeed, the VVV photometry is generally deep enough to reach well below the RR Lyrae region of the color-magnitude diagram even in the most reddened region at the distance of the Galactic center (Figure 3). The photometric completeness in this region measured from red clump giants at 14.3<K s <15.9, the magnitude range of the spanned by the observed RR Lyrae, has an average value of 80% (Valenti et al 2016). However, the variable seeing and uneven sampling of the observed epochs contribute to further reducing the completeness of our sample.…”

Section: Vvv Survey Photometrymentioning

confidence: 99%

Discovery of Rr Lyrae Stars in the Nuclear Bulge of the Milky Way

Minniti

Ramos

Zoccali

et al. 2016

ApJL

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Galactic nuclei, such as that of the Milky Way, are extreme regions with high stellar densities, and in most cases, the hosts of a supermassive black hole. One of the scenarios proposed for the formation of the Galactic nucleus is merging of primordial globular clusters. An implication of this model is that this region should host stars that are characteristically found in old Milky Way globular clusters. RR Lyrae stars are primary distance indicators, well known representatives of old and metal-poor stellar populations, and therefore are regularly found in globular clusters. Here we report the discovery of a dozen RR Lyrae type ab stars in the vicinity of the Galactic center, i.e., in the so-called nuclear stellar bulge of the Milky Way. This discovery provides the first direct observational evidence that the Galactic nuclear stellar bulge contains ancient stars (>10 Gyr old). Based on this we conclude that merging globular clusters likely contributed to the build-up of the high stellar density in the nuclear stellar bulge of the Milky Way.

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Stellar density profile and mass of the Milky Way bulge from VVV data

Cited by 103 publications

References 32 publications

Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE

Comparing the properties of the X-shaped bulges of NGC 4710 and the Milky Way with MUSE

The Number of Dwarf Satellites of Disk Galaxies versus their Bulge Mass in the Standard Model of Cosmology

Discovery of Rr Lyrae Stars in the Nuclear Bulge of the Milky Way

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