A Catalog of Parameters for Globular Clusters in the Milky Way

“King (2002) demonstrated that the rate of stellar collisions (per cluster and per year) in a King model GC is about Γc = 5 × 10 −15(Σ30rc) 1/2, where Σ0 is the central surface brightness in units of L⊙V pc −2 (equivalent to µv = 26.41), and rc is the core radius in parsecs (taken from Harris 1996).”

“Nevertheless, the statistics appear to indicate that generally speaking, the structure of NSCs is closer to that of UCDs (C = 63 is the median concentration of 40 UCDs in Mieske et al. 2013) than to that of a typical Galactic GC (C = 32 is the median concentration in Harris 1996).”

“These authors found that the change in the fraction in the two RGBs occurs at radial distance close to the half-mass radius of the cluster (rh=2.34 arcmin, Harris 1996, 2003) and becomes much stronger at larger radial radii.”

“…GC system mass of Local Group (LG) dwarf galaxies is estimated by summing the individual GC stellar masses inferred from V-band photometry (Webbink 1985; Da Costa & Mould 1988; Harris 1996) and applying a mass-to-light ratio of 2.2 for an old, metal-poor stellar population (Bruzual & Charlot 2003).”

“We use the 2003 version of the Harris (1996) catalogue.”

“…(Univ. of Texas Press) [RC2] de Vaucouleurs, G. 1983, ApJ, 268, 451 de Vaucouleurs, G. & Peters, W.L. 1968, Nature, 220, 868 Deul, E.R. & van der Hulst, J.M. 1987, A&A, 67, 509 Harris 1996 AJ, 112, 1487 Hayes, D.S. 1983, IAU Symposium 111, Calibration of Fundamental Stellar Quantities, Eds.”

“For our comparison we selected from the catalogue by Harris (1996) the 35 globular clusters in the range of galactocentric distance 10 kpc ≤ RGC ≤ 40 kpc.”

“The RGB stars in Pisces II seem to be described equally well by both and, hence, are likely to possess metallicity in the range of −2.3 [Fe/H] −1.55 (Harris 1996).”

“These are mostly identified by the HBR parameter in the Harris (1996) catalog, with additional identification directly from inspection of available CMDs.”

“These masks can generally be separated into regions around bright stars (Hoffleit & Jaschek 1991), Milky Way globular clusters (Harris 1996, 2010 edition), open clusters (WEBDA)9, and nearby galaxies that are resolved into 9 https://webda.physics.muni.cz individual stars (Corwin 2004; Nilson 1973;…”

“However, the increased cluster distance moduli reported in these papers, which were responsible for the reduced ages, tended to be ∼0.2 mag larger than currently favored estimates (as given in the latest version of the online catalog maintained by Harris 1996).”

“Its extinction, with estimates ranging from E(B V ) ¼ 0:84 (Harris 1996, hereafter H96) to E(B V ) ¼ 1:66 (Schlegel et al. 1998, hereafter S98), has prevented detailed photometric studies in the optical.”

“Of these, the lowest-mass ones are Pal 3, 4, 5, and 14 and NGC 5466 (Harris 1996).”

“Within this procedure, the reddening and the distance modulus for NGC 1851 were taken from the Harris (1996) catalogue (2011 update), and we adopted masses of 0.85 M for all stars5 and Mbol, = 4.75 as the bolometric magnitude for the Sun, as in our previous studies.”

“Most globular clusters of the Milky Way lie below the ratios studied here (Harris 1996), i.e. are more compact and, hence can resist tidal perturbations more easily and have a smaller two-body relaxation time.”

“We have adopted a distance of d = 4.69 kpc from Woodley et al. (2012) who fit spectral energy distributions of 47 Tuc’s WDs. Additionally, our proper motion data only extends to 120′′, a small fraction of the tidal radius, rt ≈ 42′ (Harris 1996, 2010 edition).”

“The GC metallicity distributionIn massive galaxies like the Milky Way,the metallicity ([Fe/H]) and optical colour (e.g.g − z, V − I) distributions of GCs are bimodal, with peak metallicities of[Fe/H] ∼ −1.6 for metal-poor (blue) GCs and[Fe/H] ∼ −0.5 for metal-rich (red) GCs (Kinman, 1959; Zinn, 1985; Forbes,Brodie & G…”

“For reference, the apparent distance modulus of 47 Tuc listed in Harris (1996) is (m−M)V = 13.37 while Zoccali et al. (2001) found (m−M)V = 13.27.”

“…consists of 1.9 million PS1 objects located in the SDSS Stripe 82 region (310◦ > RA < 59◦, |Dec| < 1.25◦) that are brighter than 21.5 mag, have at least 23 observations (Section 2), and are at least 24′ (2 tidal radii; Harris 1996 (2010 edition)) away from the center of globular cluster NGC 7089.”

“For our target clusters we assumed the metallicities listed by Ferraro et al. (1999), the distance moduli and reddening coefficients listed by Harris (1996) and the extinction coefficients AF814W = 2.809 E(B − V ) and AF814W = 1.825 E(B−V ) (Sirianni et al. 2005).”

“M68 was chosen as a standard since it has low metallicity (Harris 1996) and low reddening.”

“This is well down the globular cluster luminosity function and only ∼ 30% of Milky Way globular clusters would evade detection at this limit (Harris 1996).”

“…globular cluster NGC 3201, we found the best matching isochrone compared to the whole ACS CMD with the isochrone parameters [M/H] = −1.39 dex (slightly above the comparable literature value [Fe/H] = −1.59 dex, Harris 1996, 2010 edition), age = 11 Gyr, extinction EB−V = 0.26, and distance = 4.8 kpc.”

“…suggests that stellar populations older than 1 Gyr have F814W (cid:2) F850LP colors of 0 : 25 (cid:6) 0 : 1 mag); filled trian g les , massive globular clusters in NGC 5128 observed by Martini & Ho (2004); open trian g les , Galactic globular clusters from the Harris (1996) catalog (note that !”

“The measured value of pc isr h B 2.5 comparable to the mean half-light radius of B3 pc for the brightest Milky Way clusters (van den Bergh 1996).”

“The Harris (1996) (2010 revision) catalogue calculates a horizontal-branch distance of 2.3 kpc for NGC 6397.”

“Combining globular cluster (Harris 1996), open cluster (Piskunov et al. 2008) and embedded cluster (Lada & Lada 2003) catalogues, we estimate that a typical star forms in a cluster of 4000 M .”

“With a mass ofM = 105.65M⊙ (McLaughlin & van der Marel 2005), and an absolute visual magnitude of MV = −8.74, as listed in the Harris catalog (Harris 1996, updated as in 2010), NGC 5286 isa 3 relatively massive GC (as a comparison, M 22 has MV = −8.50, NGC 1851 MV = −8.33 and M 2 MV = −9.03).”

“Palomar 5 is a sparse halo globular cluster at a distance of ∼ 23 kpc (Harris 1996).”

“1 For all references to Harris (1996) we have used the 2003 updated data set at the Web site http://www.physics.mcmaster.ca /Globular.html. was assumed that the observed fields coincided with the centers of the systems.”

“Unless stated otherwise, we will assume GC half-mass radii of 3 pc, which is the average halfmass radius of GCs in the MW as determined from the MW GC catalog of Harris (1996).”

“We used the central cluster densities and angular core radii θc quoted in Harris (1996) (February 2003 revision) along with the distance estimates listed in Table 4 using ρ0 = ρHarris0 d Harris/d (Djorgovski 1993), and using rc = d tan θc.”

“The black dashed line represents the observed relation, which is well-fit by a constant GC-to-halo mass ratio, MGCs = 3.5 × 10−5Mvir, over Mvir ' 1011−15M (Harris 1996; Hudson et al. 2014; Harris et al. 2015).”

“Sample Cases We provide some sample specific examples of the procedure: Milky Way: Harris (1996) (2010 edition) lists 157 GCs in the Milky Way, but many of these are extremely faint or sparse objects that would be undetectable in almost all other galaxies.”

“We use the same cut and keep only clusters with [Fe/H] ≤ −0.8 dex (metallicities from Harris 1996, 2010 edition) so as to have a pure halo sample.”

“To estimate the luminosity we assumed a stellar mass of 0.84 M , an apparent distance modulus of (m − M)V = 13.30, a reddening E(B − V) = 0.04 (Harris 1996), and bolometric corrections were taken from a 14 Gyr isochrone with [Fe/H] = −1.54 from VandenBerg et al. (2000).”

“At a distance modulus of µ = 33.05± 0.18 mag (Hjorth et al. 2017; Cantiello et al. 2018) this translates to a limit of MF606W = −4.3 ± 0.4 mag (∼ 4000L ), fainter than ∼ 99% of GCs found in the local group (Harris 1996, 2010 edition; see method of Lyman et al. 2014).”

“For this project, we observed 74 BHB stars in six metal-poor GCs. Table 1 summarizes the characteristics of the program clusters, with data drawn from the most recent version of the Harris (1996) globular cluster catalog.”

“17 shows distributions of r h /r c and c for Galactic globular clusters, with data taken from the compilation of Harris (1996).”

“…by (a) adopting the most recent and reliable value for VHB, i.e. VHB = 20.31 ± 0.01 from Di Criscienzo et al. (2011a) instead of VHB = 20.45 from Harris (1996), as done in I11a, and (b) fully propagating all the observational errors into a final error in [Fe/H]CaT for each individual star.”

“We set the core radius of the globular clusters to be rK = 1 pc, roughly equal to the median value of the core radii listed in the Harris’s compilation (Harris 1996) of Galactic globular clusters.”

“This allowed us to apply a uniform reddening correction to all stars, by correcting our final (V −K) colors for interstellar extinction using a E(B−V ) =0.12 (Harris 1996) and E(V −K)/E(B − V ) =2.70 (McCall 2004).”

“From the Harris catalog (Harris 1996) we get the following data for 47 Tuc: rh = 2.”

“Along with Pal 12, Brown et al. (1997) also studied a pair of stars in the lower metallicity outer halo cluster Rup 106 (½Fe=H ¼ 1:36 0:15; Rapo ¼ 18:5 kpc, 2003 February revision of Harris 1996).”

“Surface Brightness and Luminosity Density Profiles We compare our measured centers (Table 1) with those listed in Harris’ catalog (Harris 1996).”

“…dependence on metallicity is poorly constrained, but a rough estimate based on measurements of GCs and nearby dwarf galaxies (Sherwood & Plaut 1975; Harris 1996; Baker & Willman 2015) is 1 RR Lyrae star per 104M in z = 0 old ( 10 Gyr) stellar mass; i.e. 1 ancient RR Lyrae for every 150 ancient…”

“The size of the globular clusters is almost independent of their absolute magnitude, with an average size of <Re>=3.6±0.2 pc (Harris 1996, 2010 edition) for MW GCs and <Re>=4.3±0.2 pc for dwarf galaxies GCs (Georgiev et al. 2009).”

“In Gaia Collaboration et al. (2018d) the same offset can be seen when comparing the globular cluster mean parallaxes to the more accurate (at small parallax) values from the Harris (1996) catalogue.”

“We have compared the distribution of UCD ellipticities with those reported for GCs in NGC 5128 (Harris et al. 2002) and the Milky Way (MW; Harris 1996; online catalog version of 2003 February).”

“Metallicity values from the compilation of Harris (1996) are tabulated as well as values from the recalibrated metallicity scale of Carretta et al. (2009).”

“To obtain the stellar dispersion of NGC1052-DF2 we correct the measured values: σ2stars = σ 2 meas + σ 2 M3/M13, (1) with σM3 = 5.5 ± 0.3 km s−1 and σM13 = 7.1 ± 0.4 km s−1(Harris 1996).”

“This is shown in Figure 13 for the full sample of 139 globular clusters from Harris (1996).”

“The reddening is low; we adopt EðB V Þ ¼ 0:02 mag and a distance of 19.1 kpc from the on-line database of Harris (1996); the all-sky maps of Schlegel, Finkbeiner, & Davis (1998) yield a slightly larger E(B V ) of 0.036 mag.”

“HBR is the Horizontal Branch ratio HBR=(BR)/(B+V+R), where B, R, and V are the numbers of blue HB, red HB and RR Lyrae (from Harris 1996, updated as in 2010).”

“Approximately 4% of NGC 4472 GCs host LX&10 37 erg s−1 LMXBs, compared to about 4% in NGC 1399 (A01), ≈2- 3% in M31 (using DiStefano et al. 2002 and Barmby & Huchra 2001), and 1-4% in the Galaxy (using Liu et al. 2001 and Harris 1996).”

“For all of the stars, they assumed the average reddening of NGC 2808 given by Harris (1996) and the E(B − V)/E(V − K) value from Cardelli, Clayton & Mathis (1989).”

“Temperatures were derived from theuvby photometry using the (b− y) index and the calibration by Alonso et al. (1999), adopting E(B−V) = 0.04 (Harris 1996) for the cluster reddening.”

“We inspected the colour-magnitude diagrams of stars within 1.5rh of the centres of bulge globular clusters from (Harris 1996, 2010 version) using a PSF version of the VIRAC catalogue (Smith et al., in prep.).”

“The values of 𝑀tot and 𝜌 are inferred from Neumayer et al. (2020) for NSCs and GCs (see also Harris 1996; Georgiev et al. 2016) and from Portegies Zwart et al. (2010) for YSCs.”

“As discussed by P16, the GES median [Fe/H] and RV generally agree with reference literature values (Harris 1996, 2010).”

“(4) At least four globular clusters are noted (Figure 2) that may be associated with the stream based on both position and kinematical data (Harris 1996).”

“After these cuts, we are left with a “BHB” sample of 1457 BHB stars, a “KG” sample of 2227 KG stars, and a “Hg” sample of 65 objects comprising 16 GCls, 28 FHB stars, and 21 dSphs, with which we shall construct our RC for the non-disk region.”

“Therefore, it is at the same time the nearest bona fide extragalactic cluster and the second most massive GC in the Milky Way, after ω Cen (Harris 1996).”

“To better compare the different clusters, we have adopted the values of distance and average 1 ThecU,B,V diagram for NGC 6712 is presented in the Appendix. reddening from (Harris 1996, updated as in 2010) and shiftedth diagrams to absolute magnitudes.”

“…from https://academic.oup.com/mnrasl/article-abstract/401/1/L19/1072141 by guest on 28 July 2018 Lu et al. (2009) MW nuclear disc Dark green square Harris (1996) MW GCs Pink circle Barmby et al. (2007) M31 GCs Yellow circle Rejkuba et al. (2007) Massive Cen A GCs Green pentagon McCrady & Graham…”

“…are presented in figure 10, where the distance modulus, derived from cluster distances of d = 84.2 and 23.2 kpc for NGC 2419 and Pal 5, respectively (Harris 1996), has been subtracted from the dereddened apparent magnitude g. Stars within 8′ of the center of NGC 2419 and within 14′ of the center…”

“For the Sagittarius clusters, we adopt the individual apparent distance moduli from Harris (1996) (1999 update), and have der ddened them using the quoted colour excesses (also listed by Harris) and the extinction laws described above to obtain the values in Table 4.”

“The latter are very similar to the metal abundances adopted by W. Harris in the latest edition (2010) of his on-line catalog of globular cluster parameters (Harris 1996).”