The Milky Way Nuclear Star Cluster beyond 1 pc
Anja Feldmeier, Nadine Neumayer, Anil Seth, Rainer Schödel, P. T. de Zeeuw, Nora Lützgendorf, C. J. Walcher, Shogo Nishiyama, Markus Kissler-Patig
Oct. 1, 2013 Anja Feldmeier Nuclear Star Clusters (NSCs)
NGC 4395 • Detected in 50% to 75% of all galaxies • Half-light radius 2-5 pc 6 7 • Dynamical mass 10 - 10 Msun Milky Way • Complex SF history • Scaling relations with galaxy properties • Some contain a MBH
NGC 4244
Oct. 1, 2013 Anja Feldmeier 2 Nuclear Star Clusters (NSCs)
Oct. 1, 2013 Anja Feldmeier 3 Kinematic data set • ISAAC long slit spectrograph • Central field: ~4’x3.5’ • + 6 fields of 2’x16” size
Oct. 1, 2013 Anja Feldmeier 4 Kinematic data set • ISAAC long slit spectrograph • Central field: ~4’x3.5’ • + 6 fields of 2’x16” size
Oct. 1, 2013 Anja Feldmeier 5 Kinematic data set • ISAAC long slit spectrograph • Central field: ~4’x3.5’ • + 6 fields of 2’x16” size • ~2.29 – 2.41 micron, • spectral resolution 68 km/s
Oct. 1, 2013 Anja Feldmeier 6 Kinematic data set
Full area 4’ x 3.5’ ~ 9.6 x 8.4 pc Binning to 2.22” x 2.22”
Oct. 1, 2013 Anja Feldmeier 7 Kinematic data set
Full area 4’ x 3.5’ ~ 9.6 x 8.4 pc Binning to 2.22” x 2.22”
Foreground stars removed: 2MASS point source catalog (Skrutskie et al. 2006) & SIRIUS/IRSF catalog (Nishiyama et al. 2006) Only Stars with 1.5 Oct. 1, 2013 Anja Feldmeier 8 H2 gas emission • Gaussian fit to H2 emission line at 2.4066 µm 1-0 Q(1) Velocity Flux 40 40 20 20 0 103 km/s -93 km/s 0 arcsec arcsec -20 -20 -40 -40 -60 -60 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec Velocity [km/s] lg (maximum flux) -110.00 -82.50 -55.00 -27.50 0.00 27.50 55.00 82.50 110.00 -1.30 -1.14 -0.98 -0.81 -0.65 -0.49 -0.33 -0.16 0.00 Oct. 1, 2013 Anja Feldmeier 9 H2 gas emission • Gaussian fit to H2 emission line at 2.4066 µm 1-0 Q(1) Velocity Velocity dispersion 40 40 20 20 0 103 km/s -93 km/s 0 arcsec arcsec -20 -20 > 90 km/s -40 -40 -60 -60 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec Velocity [km/s] Velocity dispersion [km/s] -110.00 -82.50 -55.00 -27.50 0.00 27.50 55.00 82.50 110.00 0.00 11.25 22.50 33.75 45.00 56.25 67.50 78.75 90.00 Oct. 1, 2013 Anja Feldmeier 10 H2 gas emission • Gaussian fit to H2 emission line at 2.4066 µm 1-0 Q(1) [µm] [µm] 2.402 2.404 2.406 2.408 2.410 2.402 2.404 2.406 2.408 2.410 1000 2500 800 2000 600 Flux Flux 400 1500 200 960 980 1000 1020 960 980 1000 1020 pixel pixel Oct. 1, 2013 Anja Feldmeier 11 Stellar CO absorption • pPXF fit to absorption lines (Cappellari & Emsellem 2004) • High resolution spectra (Wallace & Hinkle 1996) convolved to lower resolution Oct. 1, 2013 Anja Feldmeier 12 Stellar CO absorption Comparison to previous results (McGinn et al. 1989) r (parsec) r (parsec) -4 -2 0 2 4 -4 -2 0 2 4 200 100 50 150 0 100 (km/s) σ V (km/s) -50 50 -100 ISAAC data ISAAC data, forground stars removed McGinn et al. 1989 -150 0 -100 -50 0 50 100 -100 -50 0 50 100 r (arcsec) r (arcsec) Oct. 1, 2013 Anja Feldmeier 13 Stellar CO absorption Voronoi binning (Cappellari & Copin 2003) effect of binning Velocity Velocity dispersion 150 120 150 250 90 219 100 60 100 188 30 156 50 0 50 125 arcsec arcsec -30 94 Velocity [km/s] 0 0 -60 Velocity dispersion [km/s] 63 -90 31 -50 -50 -120 0 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec S/N =20, resolution ~3.5” or 0.14 pc Equivalent to Galaxy at ~290 kpc distance observed with 0.1” resolution Oct. 1, 2013 Anja Feldmeier 14 Stellar CO absorption Voronoi binning (Cappellari & Copin 2003) effect of binning Velocity Velocity dispersion 150 120 150 250 90 219 100 60 100 188 30 156 50 0 50 125 arcsec arcsec -30 94 Velocity [km/s] 0 0 -60 Velocity dispersion [km/s] 63 -90 31 -50 -50 -120 0 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec S/N =40, resolution ~12” or 0.5 pc Equivalent to Galaxy at ~1 Mpc distance observed with 0.1” resolution Oct. 1, 2013 Anja Feldmeier 15 Stellar CO absorption Voronoi binning (Cappellari & Copin 2003) effect of binning Velocity Velocity dispersion 150 120 150 250 90 219 100 60 100 188 30 156 50 0 50 125 arcsec arcsec -30 94 Velocity [km/s] 0 0 -60 Velocity dispersion [km/s] 63 -90 31 -50 -50 -120 0 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec S/N =60, resolution ~20” or 0.8 pc Equivalent to Galaxy at ~1.6 Mpc distance observed with 0.1” resolution Oct. 1, 2013 Anja Feldmeier 16 Stellar CO absorption effect of foreground stars Velocity Velocity dispersion 150 120 150 250 90 219 100 60 100 188 30 156 50 0 50 125 arcsec arcsec -30 94 Velocity [km/s] 0 0 -60 Velocity dispersion [km/s] 63 -90 31 -50 -50 -120 0 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec S/N =40, including foreground stars Oct. 1, 2013 Anja Feldmeier 17 Stellar CO absorption effect of foreground stars Velocity Velocity dispersion 150 120 150 250 90 219 100 60 100 188 30 156 50 0 50 125 arcsec arcsec -30 94 Velocity [km/s] 0 0 -60 Velocity dispersion [km/s] 63 -90 31 -50 -50 -120 0 -100 -50 0 50 100 -100 -50 0 50 100 arcsec arcsec S/N =40, after foreground star correction Oct. 1, 2013 Anja Feldmeier 18 Stellar CO absorption 1-dim profile Circular bins around Sgr A* 2 2 Vrms = SQRT(V +σ ) Oct. 1, 2013 Anja Feldmeier 19 Stellar CO absorption 1-dim profile r (parsec) 0.1 1.0 10.0 with foreground stars 200 without foreground stars with IRS7 150 (km/s) 100 RMS V 50 0 1 10 100 1000 r (arcsec) Circular bins around Sgr A* 2 2 Vrms = SQRT(V +σ ) Oct. 1, 2013 Anja Feldmeier 20 Photometry from Spitzer/IRAC survey 4.5µm image (Stolovy et al. 2006) Dust and extinction corrected (Poster by Devaky Kunneriath) Oct. 1, 2013 Anja Feldmeier 21 Photometry from Spitzer/IRAC survey Multi-Gaussian expansion fit (Cappellari 2002) r (parsec) 0.01 0.10 1.00 10.00 100.00 106 105 4 2 10 3 /parsec 10 • O L 102 101 major axis 100 10 100 1000 10000 r (arcsec) Oct. 1, 2013 Anja Feldmeier 22 Photometry from Spitzer/IRAC survey Multi-Gaussian expansion fit (Cappellari 2002) r (parsec) 0.01 0.10 1.00 10.00 100.00 106 105 4 2 10 3 /parsec 10 • O L 102 101 major axis minor 100 10 100 1000 10000 r (arcsec) Oct. 1, 2013 Anja Feldmeier 23 Photometry from Spitzer/IRAC survey Multi-Gaussian expansion fit (Cappellari 2002) r (parsec) 0.01 0.10 1.00 10.00 100.00 106 105 4 2 10 3 /parsec 10 • O L 102 major axis 101 minor axis upper error lower error 100 10 100 1000 10000 r (arcsec) Oct. 1, 2013 Anja Feldmeier 24 Axisymmetric Jeans models • Jeans Anisotropic MGE dynamical models (JAM, Cappellari 2008) • Inclination=90°, constant anisotropy β • constant M/L r (parsec) 0.1 1.0 10.0 200 Best fit with χ2 = 21.84, 150 β = 0.6 (radial), +0.28 (km/s) M/L4.5µm = 0.32 -0.17 Msun/L4.5µm,sun RMS M = 2.e6 ±1.e6 M V BH sun 100 50 1 10 100 r (arcsec) Oct. 1, 2013 Anja Feldmeier 25 Conclusions • First map of stellar velocities of the NSC • Foreground star removal has no big influence on the results • Result of black hole mass fit from Jeans model is largely consistent with black hole mass from direct measurements • Black hole mass is too low à do we underestimate black hole masses in other Galaxies? • Radially varying M/L can fit the required black hole mass à constrain the M/L with stellar population analysis using KMOS data Oct. 1, 2013 Anja Feldmeier 26