A Catalog of Parameters for Globular Clusters in the Milky Way

“In this paper, we extend the pioneering work of Anderson & King (2003a) and measure, for the first time, the rotation curve of 47 Tuc in the plane of the sky from the center of the cluster out to about 13′ (about 4 half-light radii, Harris 1996).”

“…members clump in restricted ranges of RV and [Fe/H] values (in agreement with the literature, the metallicities are centered at [Fe/H]=−0.49, −1.06, and −0.56 in NGC 5927, NGC 6171 and NGC 6496, respectively, and have intrinsic dispersions of the same order of the uncertainties; e.g., Harris 1996).”

“For the S15 and S17 models we assume a cluster metallicity of Z = 0.0005, close to the average metallicity of ω Cen according to Harris (1996) and Johnson & Pilachowski (2010), while for the B10 and F12 models we assume a metallicity of Z = 0.0002, which is the metallicity closest to the…”

“There are 36 globular clusters in the most updated version of the Harris catalog (Harris 1996) in the area surveyed by VVV.”

“A comparison with 47 Tuc ([Fe/H] = -0.71, Harris 1996) was carried out by Ortolani et al. (1990), Guarnieri et al. (1998) and Zoccali et al. (2001); the latter two papers used the same data set and values E(V-I) = 0.95 and 0.80, or E(B-V) = 0.7 and 0.6, respectively, were found.”

“The total initial mass of the cluster was chosen MGC = 4.7× 105 M⊙, i.e. a value compatible with masses of galactic globular clusters lying inside 4.5 kpc from the MW center (see Harris (1996) and Pryor & Meylan (1993)).”

“For comparison, the average [Fe/H] for the MW sample with Rproj > 15 kpc is -1.70±0.23 dex (Harris 1996).”

“Table 1 also includes the HB type of the clusters taken from Harris (1996).”

“…( M⋆M⊙ ) of our stars by inverting the canonical equation: log( g⋆g⊙ ) = 4 · log( T⋆ T⊙ )− log( L⋆L⊙ ) + log( M⋆ M⊙ ) where log( L⋆L⊙ ) = − Mbol−4.74 2.5 and Mbol = MV +BC = V − (m−M)V +BC Bolometric correction (BC) was taken from Flower (1996), and distance modulus (m − M)V from Harris (1996).”

“Harris (1996) gives [Fe/H]=-1.44 for NGC 6522, and in these cases the derived ∆(B-V) is close to the E(B-V) value.”

“Reddening and metallicity values for the sample clusters revised by Barbuy et al. (1998) and the compilation by Harris (1996), as given at http://www.physics.mcmaster.ca/Globular.html, as well as recent spectroscopic determinations are shown in Table 1.”

“For the luminous early-type galaxies, as well as the Milky Way and M31, we fit a homoscedastic (equal variance) Gaussian mixture model to the V − I colors to estimate the values of the blue and red peaks, as well as credible posterior intervals (the Bayesian equivalent of confidence intervals) around those values.”

“…al. (2015) derive a distance of 4.15 kpc ((m−M)0 ∼13.09) which is lower than the values in the Harris catalog (4.5 kpc ((m−M)0 ∼13.27) and (m−M)V=13.37, Harris 1996, 2010 edition); the eclipsing binary distance measurement ((m−M)V= 13.35, Thompson et al. 2010); the result based on the white dwarf…”

“In Figure 7, we plot rc/rhl (taken from Harris 1996, 2010 edition) versus the number (NBH, left panel) and total mass (MBH, right panel) of retained BHs for each of the 50 GCs analyzed in respective units of the star count (Ncluster) and total cluster mass (Mcluster).”

“…26 demonstrates velocity dispersions of our metal-poor galaxies as a function of V-band absolute magnitude in comparison with the stellar velocity dispersions of massive galaxies (Prugniel & Simien 1996), dwarf galaxies (a compiled catalog of Lin & Ishak 2016), and globular clusters (Harris 1996).”

“…NGC 362 (Boyer et al. 2009), and Omega Cen (McDonald et al. 2011b); these three clusters have metallicities [Fe/H] ≈ −0.7, −1.3, and −1.5, respectively (Harris 1996, 2010 edition).4 The featureless emission might be attributed to hot amorphous carbon grains, but carbon solids are not expected to…”

“This is a moderately metal-rich object ([Fe/H]= −1.26 dex1 in the 2011 update of the Harris 1996, H96 hereinafter, catalogue that is based on the metallicity scale of Carretta et al. 2009c) seen projected toward the Small Magellanic Cloud.”

“The specific frequency of RR Lyrae stars in M22 is SRR = 10.4, where SRR = NRR × 100.4(7.5+MV ) and MV = −8.50 (Harris 1996, 2010 update) is the cluster’s integrated absolute magnitude in V.”

“Interstellar extinctions for the filter systems used were estimated according to Cardelli et al. (1989) and Sirianni et al. (2005), based on the E(B−V ) values listed in the updated catalog of Harris (1996).”

“Since Carretta et al. (2009c) derive the metallicity of thiscluster (-1.31± 0.09 dex) from the 2003 edition of Harris (1996), we simply adopt the correspondingvalue listed in Ha10 (-1.26 dex), at the expense of not having an error estimate.”

“Among the approximately 33 clusters listed in the Harris (1996) compilation with [Fe/H] ≥ −0.8 M 71 (NGC 6838) and 47 Tuc (NGC 104) are among the most easily studied due to their closeness (although the reddening of M 71 is substantial, with some differential reddening evident, its low…”

“It should be noted that the metallicities of individual stars in the LMC and ω Cen from the Gratton et al. (2004) study were calibrated using the [Fe/H] scale of Harris (1996), which is typically closer in value to the ZW84 system.”

“According to Harris (1996), the metallicities are [Fe/H] = −2.15 (NGC 2419, Suntzeff et al. 1988), −2.23 (M68, Lee et al. 2005), and −2.37 (M15, Takeda et al. 2009).”

“Surface gravities were derived from these temperatures and the position of stars on the CMD, adopting reddening and an apparent distance modulus (0.12 and 17.47 mag) from the web update of the Harris (1996) catalogue.”

“Therefore, this cluster joins the ensemble of other GCs producing a nice correlation with the cluster total mass (represented by the proxy of the total absolute magnitude,MV = −8.16 for NGC 4833 from Harris 1996), established in Carretta et al. (2010a) and reproduced in Fig.”

“Given the luminosity of NGC 6752 (Harris 1996) and a mass-to-light ratio of M/Lv = 3, we evaluate its actual mass to be ∼3× 105 M .”

“We used the observed color of the binary, (B − V ) = 0.548 (see Table 1) together with a reddening of E(B − V ) = 0.04 (Harris 1996; Gratton et al. 2003; Percival et al. 2002) to derive (B − V )0 = 0.508.”

“-ENHANCED LICK SPECTRAL INDICES 177 (2002).4 We use the Harris (1996) compilation5 for [Fe/H] of the Milky Way GCs. Figures 1, 2, 3, 4, 5, and 6 show [Fe/H] versus Lick indices in order to take advantage of independent measurements of mean [Fe/H] and [ /Fe] of the Milky Way GCs.”

“For the Milky Way, this restriction would encompass 85-90% of GCs (Harris 1996).”

“B − V colour limits of 0.55 and 1.05 were also imposed and correspond to [Fe/H] values of −2.5 and +0.2 for Galactic GCs, according to a linear fit to the data in the Harris (1996) catalogue.”

“To compare the mass function of surviving clusters with observations, we calculate the masses of Galactic GCs from the absolute V-band magnitude MV in Harris (1996) with the luminosity-dependent mass-to-light ratio M LV = 1.3 + 4.5 1 + e2MV+21.4 suggested by Harris et al. (2017).”

“The top graph in Figure 4 shows this relationship for the globular clusters that have galactocentric distances, Rgc≤ 6kpc (data from the 1999 June 22 revision of the Harris 1996 catalogue).”

“…6715 is strongly contaminated by stars of the Sgr dwarf galaxy, in which is embedded (Sarajedini & Layden, 1995); NGC 6441 is located in the Galactic bulge and suffers from strong (and uncertain) extinction (E(B-V)=0.47, Harris, 1996); NGC 2419 is one of the most distant Galactic clusters known.”

“To further remove potential globular cluster contaminates we excluded any stars if they fell within two tidal radii and had velocities within 25 km s−1 of the cluster mean for all clusters listed in the 2003 version of the Harris catalog (Harris 1996).”

“PSR J1824−2452A is associated with the globular cluster M28 (NGC 6626) which has an independent distance estimate of 5.5 kpc (Harris 1996).”

“…the CMD reveals a population of GCs with colors and luminosities that are consistent with thosef halo GCs in our Galaxy (taken from the database of Harris 1996), as well as a larger population with a mean color that is consistent with those of the aforementioned brightest, metalrich GCs…”

“The core relaxation times for most clusters are 107 − 108 years (Harris 1996), so most binaries will return to the core in less than a million years.”

“…a globular cluster are WD-WD binaries (Shara & Hurley 2002); (5) the triple fraction relative to the binary fraction is the same as the field, i.e., 0.2 (Raghavan et al. 2010);5 and (6) the typical velocity dispersion of a globular cluster is 6 km s−1 (Harris 1996; Binney & Tremaine 2008, p. 31).”

“The black hole mass is expressed in solar units, the distance in kpc, the X-ray luminosity in erg s−1 and the radio flux in µJy; raw data are taken from Harris (1996) and the computation of the parameters is described in the text.”

“We note that a planet has been detected within a binary pulsar system in M4 (Thorsett et al. 1999) which is metal-poor compared to 47 Tuc (Harris 1996).”

“That work used the scale of Kraft & Ivans (2003) for all the clusters except those with an asterisk, which use that of Harris (1996).”

“In other cases, we drew an old (∼ 12 Gyr) isochrone corresponding to the metallicity of the cluster (Harris 1996, updated 2010).”

“Effective temperature and gravity values are based on the best-fitting Dartmouth isochrones (Dotter et al. 2008), obtained by assuming a distance modulus (m−M)0=13.69 and a reddening E(B − V )=0.13, similar to the values quoted in 18 Harris (1996), and an age of 13.5 Gyr.”

“We use the implied masses from the absolute visual magnitudes in Harris (1996)5 of those massive (M > 105 M ) 4 We have verified that changing this number in the range 3−7 does not significantly change the numbers quoted here.”

“For comparison, the median value of the half-mass radius for 141 globular clusters with known structural parameters from Harris (1996) is only 1.0 arcmin.”

“Today we know of about 150 globular clusters in the Milky Way (Harris, 1996), and more clusters might be hidden behind the high-absorption regions of the Galactic disk.”

“This GC hoststwo main stellar populations with different content of C, Mg, Al, and Na (Yong et al. 2014) and is among the ten most luminous Galactic GCs (MV=−9.18, Harris 1996 updated as in 2010).”

“We adopted for the cluster a mean reddening of E(B-V)=0.36 (Harris, 1996).”

“In Figure 2, we show the absolute magnitudes of Milky Way globular clusters as a function of their metallicities, where the data are from Harris (1996).”

“A reddening of E(B − V ) = 0.12 mag was assumed (Harris 1996).”

“Our radial extension covers the whole cluster from the center to beyond the tidal radius (rtidal=11.7 arcmin, Harris 1996, 2003).”

“Observationally a peak has been detected in M92 (NGC 6341) at (Ferraro et al. 1999) or , on adopt-V p 14.65 0.05 M p 0.0V ing an apparent distance modulus of (m M)V p 14.64 from the 1999 version of the catalog of Milky Way globular cluster properties compiled by Harris (1996).”

“However, using its current values for half-light radius rh = 2.23 pc and King concentration parameter c = 39 (Harris 1996), an age of 13 Gyr, and the methodology outlined in Section 3.3, we calculate a present-day escape velocity vesc = 16 km s−1 and a vesc,7 = 52 km s−1 for M 4 (assuming no…”

“We consider whether the GCs that do show r-process dispersion and those that do not have differences in their structural (Harris 1996) or kinematic (Dinescu et al. 1999; Casetti-Dinescu et al. 2007) properties, horizontal branch morphologies (Lee 1990), or RR Lyr types (Clement et al. 2001).”

“The latter quantity, the metallicity, and other properties are from the latest version of the electronic catalog compiled by Harris (1996)9; and are summarized in Table 7, which also reports the observed SBF values.”

“∼90% of Milky Way glob- ular clusters have half-light radii smaller than 3 pc (Harris 1996) and their counterparts in NGC 3115 and NGC 3379 are expected to have similar size distributions (e.g. Kundu & Whitmore 1998; Larsen et al. 2001).”

“This is comparable to the most compact young LMC clusters and is also a typical value for Milky Way globular clusters (Peterson & King 1975; Harris 1996).”

“We also show the galactocentric offsets of satellites 132 and globular clusters 133 of the Milky Way (MW).”

“…= 26.4 ± 0.5 pc at the assumed distance of 71 ± 1.3 kpc and implies a 3D half-light radius of about 35.6 ± 0.6 pc. Jordi et al. derived the age of the cluster to be 11.5 ± 0.5 Gyr by adopting [Fe/H] = −1.50 for the metallicity (Harris 1996) from the best isochrone fitting of Dotter et al. (2007).”

“5 E X P E C T E D γ- R AY F L U X E S F RO M S P E C I F I C O B J E C T S As an example, we perform calculations of the γ -ray fluxes expected on the Earth from four GCs (selected from the catalogue of GCs, Harris 1996).”

“The V and I data used in this investigation come from the database of original and archival observations that have been collected, reduced, and calibrated by one of the authors (PBS) in an ongoing effort to provide homo- 17 Following Harris (1996) we assumed for the center of the cluster the coordinates: α = 10h17m36′…”

“Indeed, the reported “Specific frequency of RR Lyrae variables” in NGC2808 (0.3) is among the lowest (Harris 1996).”

“As the distance of the GCs spans a rather wide range (cf. Harris 1996), the sensitivity of the observations can differ in the searches toward different clusters and hence induce selection effects in the observed sample (Ransom 2008).”

“Theoretical analysis based on the current estimated relaxation times for the GGCs indicate that the majority of the GGCs should have had a deep collapse (Djorgovski 1993; Harris 1996).”

“…that M5 has not yet experienced core collapse, and they are in good agreement with those quoted by McLaughlin & van der Marel (2005) rc ¼ 26:300 and c ¼ 1:71, and marginally consistent with those listed by Harris (1996) rc ¼ 25:200 and c ¼ 1:83, both derived from the surface brightness profile.”

“The ACF of a simulated random (unclustered) field of the same number of stars is shown in red for reference. of known Galactic globular clusters (Pal 12,c = 2.98; Harris 1996, 2010 Edition4).”

“This is a reasonable first approximation in our case, since the cooling timescales among ourWD population are short and comparable to the core relaxation time of 108 yr (Harris 1996).”

“Finally, we recently realized (Marsakov, private communication) that the 2003 version of the Harris (1996) catalogue reports significantly revised estimates of the reddening and distance modulus of Ter 3 [E(B-V)=0.72; (m − M)V = 16.61] with respect to the 1996 version that was used by BFI03…”

“Column 2 gives the spectral type from the reference mentioned in Col. 3, Cols. 4 and 5 list Mv (adopting a distance modulus of 13.92; Harris 1996) and B − V from Mayor et al. 1998, Cols. 6–8 (taken from Mayor et al. 1998) give the uncertainty Vr of the mean radial velocity, the rms value σVr for…”