Field/isolated lenticular galaxies with high <i>SN</i> values: the case of NGC 4546 and its globular cluster system

Escudero, Carlos; Faifer, Favio Raúl; Castelli, A. V. Smith; Norris, Mark A.; Forte, J. C.

doi:10.1093/mnras/staa392

Cited by 11 publications

(20 citation statements)

References 86 publications

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“…Between the peaks at g − z = 0.96 and g − z = 1.24 which were established by Cho et al (2012) using KMM, we observe an overdensity which could be an indication of a third peak. A similar result was presented in Escudero et al (2020), where an intermediate subpopulation is more prominent in g − z than in g − i .…”

Section: Colour Distribution and Subpopulationssupporting

confidence: 84%

Wide-field study of the peculiar globular cluster system hosted by the field lenticular NGC 1172

Ennis

Caso

Bassino

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present a wide-field study of the globular cluster system (GCS) of the field lenticular galaxy NGC 1172, based on observations from GMOS/Gemini (optical), FourStar/Magellan (NIR), and archival data from ACS/HST (optical). This analysis covers the full extension of the GCS, and results in a value of specific frequency (SN = 8.6 ± 1.5) peculiarly high for an intermediate-mass galaxy in a low-density environment such as this one. We find that the GCS appears to be bimodal, although the colour distribution is narrow and does not allow for an accurate separation of the subpopulations. However, the combination of optical and NIR filters allows us to obtain an estimation of the metallicity distribution based on the photometry, which supports bimodality. We conclude that the presence of a large fraction of metal-poor globular clusters (GCs) and the high specific frequency point to NGC 1172 having accreted a significant amount of GCs from low-mass satellites in the past.

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Section: Colour Distribution and Subpopulationssupporting

confidence: 84%

Wide-field study of the peculiar globular cluster system hosted by the field lenticular NGC 1172

Ennis

Caso

Bassino

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…As seen in Figure 8, although the position of these peaks results in an acceptable agreement with the substructures in our histograms, mainly in the red GC subpopulation, the presence of a group of objects with intermediate colours in (𝑔 − 𝑖 ) 0 ∼ 0.95 and (𝑔 − 𝑧) 0 ∼ 1.2 mag stands out. Furthermore, the position of the intermediate peak in this galaxy is consistent with other GC systems that would present more than two GC subpopulations (Blom et al 2012;Escudero et al 2020).…”

Section: Gc Subpopulationssupporting

confidence: 87%

“…The detection, classification and photometry of GC candidates of NGC 4382 was performed following the guidelines of Escudero et al (2018Escudero et al ( , 2020. In summary, we use the combination of the package (Stetson 1987) of to obtain the point spread function (PSF) photometry of the detected objects, together with the versatility of SE software (Bertin & Arnouts 1996) to classify.…”

Section: Photometrymentioning

confidence: 99%

“…It is clear that the galaxy has more than two families of GCs in optical colours, so a correct separation between them is necessary to correctly analyze their properties. In this context, we tackle the analysis using the same procedure as in Escudero et al (2020), according to the filters available in our catalogue, which allows us to better disentangle the underlaying multiple subpopulations present in the global GC system of the galaxy. In this case, we use the joint information of the colour indices (𝑔 −𝑖 ) 0 and (𝑔 −𝑟 ) 0 in the colourcolour diagram (see Section 3.2), together with the Gaussian Mixture Model (GMM) code through the open-source machine learning library -2 for python.…”

Section: Gc Subpopulationsmentioning

confidence: 99%

“…The difference in metallicity may indicate distinct cluster formation mechanisms for the two populations (blue or metal-poor and red or metal-rich), with small age differences allowed within the uncertainties of current age estimates. However, various GC systems associated with early-type galaxies have turned out to be complex systems showing multiple subpopulations of clusters (Blom et al 2012;Caso et al 2013Caso et al , 2015Escudero et al 2015;Sesto et al 2016;Bassino & Caso 2017;Sesto et al 2018;Escudero et al 2020).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The complex globular cluster system of the S0 galaxy NGC 4382 in the outskirts of the Virgo Cluster

Escudero,

Cortesi,

Faifer

et al. 2022

Preprint

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NGC 4382 is a merger-remnant galaxy that has been classified as morphological type E2, S0, and even Sa. In this work, we performed a photometric and spectroscopic analysis of the globular cluster (GC) system of this peculiar galaxy in order to provide additional information about its history. We used a combination of photometric data in different filters, and multi-object and long-slit spectroscopic data obtained using the Gemini/GMOS instrument. The photometric analysis of the GC system, using the Gaussian Mixture Model algorithm in the colour plane, reveals a complex colour distribution within 𝑅 gal < 5 arcmin (26.1 kpc), showing four different groups: the typical blue and red subpopulations, a group with intermediate colours, and the fourth group towards even redder colours. From the spectroscopic analysis of 47 GCs, confirmed members of NGC 4382 based on radial velocities, we verified 3 of the 4 photometric groups from the analysis of their stellar populations using the ULySS code. NGC 4382 presents the classic blue (10.4 ± 2.8 Gyr, [Fe/H] = −1.48 ± 0.18 dex) and red (12.1 ± 2.3 Gyr, [Fe/H] = −0.64 ± 0.26 dex) GCs formed earlier in the lifetime of the galaxy, and a third group of young GCs (2.2 ± 0.9 Gyr; [Fe/H] = −0.05 ± 0.28 dex). Finally, analysis of long-slit data of the galaxy reveals a luminosity-weighted mean age for the stellar population of ∼2.7 Gyr, and an increasing metallicity from [Fe/H]=−0.1 to +0.2 dex in 𝑅 gal < 10 arcsec (0.87 kpc). These values, and other morphological signatures in the galaxy, are in good agreement with the younger group of GCs, indicating a common origin as a result of a recent merger.

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Measuring the mass of the supermassive black hole of the lenticular galaxy NGC 4546

Ricci

Steiner

2020

Monthly Notices of the Royal Astronomical Society

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Most galaxies with a well-structured bulge host a supermassive black hole (SMBH) in their centre. Stellar kinematics models applied to adaptive optics (AO) assisted integral field unit observations are well-suited to measure the SMBH mass (MBH) and also the total mass-to-light ratio [(M/L)TOT] and possible anisotropies in the stellar velocity distribution in the central region of galaxies. In this work, we used new AO assisted Near-Infrared Integral Field Spectrometer (NIFS) observations and also photometric data from the Hubble Space Telescope Legacy Archive of the galaxy NGC 4546 in order to determine its SMBH mass. To do this, we applied the Jeans Anisotropic Modelling (JAM) method to fit the average second velocity moment in the line of sight $(\overline{v^2_{\mathrm{ los}}})$ of the stellar structure. In addition, we also obtained (M/L)TOT and the classical anisotropy parameter βz = 1-(σz/σR)2 for this object within a field of view of 200 × 200 pc2. Maps of the stellar radial velocity and of the velocity dispersion were built for this galaxy using the penalized pixel fitting (ppxf) technique. We applied the Multi Gaussian Expansion procedure to fit the stellar brightness distribution. Using JAM, the best-fitting model for $\overline{v^2_{\mathrm{ los}}}$ of the stellar structure was obtained with (M/L)TOT = 4.34 ± 0.07 (Johnson’s R band), MBH = (2.56 ± 0.16) × 108 M⊙ and βz = −0.015 ± 0.03 (3σ confidence level). With these results, we found that NGC 4546 follows the MBH × σ relation. We also measured the central velocity dispersion within a radius of 1 arcsec of this object as σc = 241 ± 2 km s−1.

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Field/isolated lenticular galaxies with high SN values: the case of NGC 4546 and its globular cluster system

Cited by 11 publications

References 86 publications

Wide-field study of the peculiar globular cluster system hosted by the field lenticular NGC 1172

Wide-field study of the peculiar globular cluster system hosted by the field lenticular NGC 1172

The complex globular cluster system of the S0 galaxy NGC 4382 in the outskirts of the Virgo Cluster

Measuring the mass of the supermassive black hole of the lenticular galaxy NGC 4546

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