The ACS Coma Cluster Treasury Survey: Velocity dispersions of cluster galaxies from Keck/DEIMOS spectra

• 1. Nottingham Seminar, 26th May 2010 Arna Karick (LJMU) Ehsan Kourkchi (Sharif) Habib Khosroshahi (Sharif) Dave Carter (LJMU) Velocity dispersions of cluster galaxies from Keck/DEIMOS spectra The ACS Coma Cluster Treasury Survey

2. Why is Coma Special? The HST/ACS Coma Cluster Treasury Survey Science Highlights Keck/DEIMOS Spectroscopy of cluster galaxies Structural Parameter Analysis Other Projects Conclusions Talk Outline 3. WHY STUDY THE COMA CLUSTER? 4. Nearest rich and densely populated cluster in the local (z ~0.023 ~100 Mpc) universe. gal 104 Mpc-3 in the core. Several times more dense than Virgo. Bright extragalactic x-ray source. Complex cluster environment. x-ray substructure & infalling galaxies. Large samples of cluster galaxies have been studied. Local benchmark for comparative studies of galaxy evolution in different environments. Why is Coma Special? 5. NGC 4911 NGC 4839 Neumann et al. (2003) NGC 4889 Substructure revealed by ROSAT X-ray surface brightness prole out to 100. (Briel et al. 1992, White et al. 1993) Strong evidence for NGC 4839 falling in for the rst time. (Neumann et al. 2001) NGC 4839 has already passed through the centre. (Burns et al. 1994) E+A galaxies correlate with X-rays (?) Cluster substructure from velocities of ~550 cluster galaxies. (Colless & Dunn 1993) vel = 6853 km s-1, = 1083 km s-1 Signicant difference in velocity between NGC 4889 and NGC 4874 indicative of a recent merger. (Fitchett & Webster 1987) Why is Coma Special? NGC 4874 6. The Universe As We Know It Low-redshift benchmark for galaxy cluster formation. Fiducial reference for fundamental plane studies of early-type galaxy evolution. 7. The Universe As We Know It Next generation telescopes: JWST, TMT, ELT will focus on the birth of galaxies at z ~ 6 8 8. Next generation telescopes: JWST, TMT, ELT will focus on the birth of galaxies at z ~ 6 8 The Universe As We Know It 9. Compare observations with predictions of hierarchical and evolutionary models of galaxy formation 10. http://astronomy.swin.edu.au/coma/index-mm.htm http://www.astro.ljmu.ac.uk/research/coma.shtml The HST/ACS Coma Cluster Treasury Survey 11. Cycle 15 ACS Treasury Survey (PI: Carter) Covers ~270 arcmin2 of the cluster core and infall region F814W (I) and F475W (g) band images FOV: 202 x 202 (11.3 arcmin2), resolution of 0.05 Observing program terminated due to ACS failure + 7 FIELDS The Survey Professor David Carter (PI) - UK Prof. Steve Phillipps - UK Dr Avon P. Huxor - UK Mr James Price - UK Dr Mustapha Mouhcine - UK Dr Carlos Hoyos - UK Dr Neil Trentham - UK Dr John Lucey - UK Prof. Ray M. Sharples - UK A Prof. Alister Graham - Australia Mr Juan Madrid - Australia Dr Harry C. Ferguson (PI) - US Dr Jennifer Lotz - US Dr Neal A. Miller - US Dr. Brent Tully - US Dr. Kristin Chiboucas - US Prof. Bahram Mobasher - US Dr Paul Goudfrooij - US Mr Derek Hammer - US Dr Ann Hornschemeier - US Dr Dan Batcheldor - US Prof. David Merritt - US Dr Ron Marzke - US Dr Rafael Guzman - US Dr Thomas H. Puzia - Canada Dr Terry Bridges - Canada Dr Habib Khosroshahi - ARI/Iran Mr. Ehsan Kourkchi - ARI/Iran Dr Carlos del Burgo- Ireland Dr Bryan Miller- Chile Dr Bianca Poggianti - Italy Dr Alfonso Aguerri - Spain Dr Marc Balcells - Spain Dr Reynier Peletier - Netherlands Mr Mark den Brok - Netherlands Prof. Edwin Valentijn - Netherlands Dr Gijs Verdoes Kleijn - Netherlands Dr Peter Erwin - Germany Dr Yutaka Komiyama - Japan Dr Masafumi Yagi - Japan Dr Eric Peng - China 12. The Survey Figure 1. from Hammer et al. (2010) The HST/ACS Coma Cluster Survey II: Data Description and Source Catalogs Professor David Carter (PI) - UK Prof. Steve Phillipps - UK Dr Avon P. Huxor - UK Mr James Price - UK Dr Mustapha Mouhcine - UK Dr Carlos Hoyos - UK Dr Neil Trentham - UK Dr John Lucey - UK Prof. Ray M. Sharples - UK A Prof. Alister Graham - Australia Mr Juan Madrid - Australia Dr Harry C. Ferguson (PI) - US Dr Jennifer Lotz - US Dr Neal A. Miller - US Dr. Brent Tully - US Dr. Kristin Chiboucas - US Prof. Bahram Mobasher - US Dr Paul Goudfrooij - US Mr Derek Hammer - US Dr Ann Hornschemeier - US Dr Dan Batcheldor - US Prof. David Merritt - US Dr Ron Marzke - US Dr Rafael Guzman - US Dr Thomas H. Puzia - Canada Dr Terry Bridges - Canada Dr Habib Khosroshahi - ARI/Iran Mr. Ehsan Kourkchi - ARI/Iran Dr Carlos del Burgo- Ireland Dr Bryan Miller- Chile Dr Bianca Poggianti - Italy Dr Alfonso Aguerri - Spain Dr Marc Balcells - Spain Dr Reynier Peletier - Netherlands Mr Mark den Brok - Netherlands Prof. Edwin Valentijn - Netherlands Dr Gijs Verdoes Kleijn - Netherlands Dr Peter Erwin - Germany Dr Yutaka Komiyama - Japan Dr Masafumi Yagi - Japan Dr Eric Peng - China 13. Science Highlights The HST/ACS Coma Cluster Survey I - Survey objectives and design (Carter et al. 2008) *The HST/ACS Coma Cluster Survey II - Data description and source catalogs (Hammer et al. 2010 - submitted) *The HST/ACS Coma Cluster Survey III - Catalog of Structural Parameters of galaxies using (Hoyos et al. 2010 - submitted) single Sersic ts The HST/ACS Coma Cluster Survey V - Compact Stellar Systems in the Coma Cluster (Price et al. 2009) The HST/ACS Coma Cluster Survey VI - The Galaxy Luminsosity Function (Trentham et al. 2010 - submitted) Keck/LRIS Spectroscopic conrmation of Coma Cluster dwarf galaxy membership assignments (Chiboucas et al. 2010 - submitted) **Kinematic Properties of faint early type galaxies in the Coma Cluster (Kourkchi et al. 2010 - in prep) Stellar Populations of faint early type galaxies in the Coma Cluster (Karick et al. 2010 - in prep) **Thirteen gaseous stripping events in the Coma Cluster (Smith et al. 2010 - submitted) 14. Science Highlights Keck/LRIS Spectroscopic conrmation of Coma Cluster dwarf galaxy membership assignments (Chiboucas et al. 2010 - submitted) 15. Science Highlights **Thirteen gaseous stripping events in the Coma Cluster (Smith et al. 2010 - submitted) 16. Science Highlights The HST/ACS Coma Cluster Survey VI - The Galaxy Luminsosity Function (Trentham et al. 2010 - submitted) 17. Keck/DEIMOS Spectroscopy http://keckobservatory.org/ 18. What fraction of cluster galaxies are dwarfs? Motivation Figure 4. Trentham et al. (2010) - submitted 19. What fraction of cluster galaxies are dwarfs? What is their dark matter content? Motivation 20. What fraction of cluster galaxies are dwarfs? What is their dark matter content? Do they follow the same Fundamental Scaling relations as giant galaxies? Motivation (1) scaling laws reveal a great deal about the physical process governing galaxy formation (2) FaberJackson (1976) relation for ellipticals: L (4) (3) helps constrain galaxy formation models. (Dekel & Silk 1986) =5.26 galaxies dominated by dark matter =2.70 galaxies with little dark matter + const. M/L (4) Globular cluster relation: L (=1.7) Evstigneeva et al. (2006) Luminosity vs. Velocity dispersion 21. What fraction of cluster galaxies are dwarfs? What is their dark matter content? Do they follow the same Fundamental Scaling relations as giant galaxies? Can we quantify the environmental impact on dwarf galaxy evolution? Motivation (1) scaling laws reveal a great deal about the physical process governing galaxy formation (2) FaberJackson (1976) relation for ellipticals: L (4) (3) helps constrain galaxy formation models. (Dekel & Silk 1986) =5.26 galaxies dominated by dark matter =2.70 galaxies with little dark matter + const. M/L (4) Globular cluster relation: L (=1.7) 22. Keck/DEIMOS Spectroscopy of Cluster Galaxies OBSERVATIONS: March 2007 Two DEIMOS masks (~6600s) ~200 galaxies Instrument spectral resolution (red): 1.6 (FWHM), pixel size : 0.30 Blue grating (900ZD l/mm, 5500 blaze) wavelength range: 4100 7500 : Line-strength indices Red grating (1200G l/mm, 7500 blaze) wavelength range: 7500 11000 : Velocity dispersions 23. Two DEIMOS masks (~6600s) ~200 galaxies Instrument spectral resolution (red): 1.6 (FWHM), pixel size : 0.30 Blue grating (900ZD l/mm, 5500 blaze) wavelength range: 4100 7500 : Line-strength indices Red grating (1200G l/mm, 7500 blaze) wavelength range: 7500 11000 : Velocity dispersions Keck/DEIMOS Spectroscopy of Cluster Galaxies OBSERVATIONS: March 2007OBSERVATIONS: March 2007 24. Keck/DEIMOS Spectroscopy of Cluster Galaxies Source Selection: within 3 of the red sequence in a (B-R) vs. R color-magnitude diagram : -19 < MR < -16 mag galaxy morphology checked in ACS imaging 1.0 width slits for radial velocity measurements of LSB galaxies (cluster candidates) 0.7 width slits for velocity dispersion analysis 25. Keck/DEIMOS Spectroscopy of Cluster Galaxies Redshift Analysis: 50/50 galaxies are conrmed cluster members 70/153 LSB galaxy candidates are background galaxies. (rest are too low S/N) 33 UCD (bright IGC) candidates: 9/33 stars/background galaxies 8/33 probable Coma members 26. Velocity dispersions of cluster galaxies 0.7 width slits. Dispersion: 0.33 /pix. Resolving power, R = 5000 (velocity width ~ 25 km s-1) Spectra reduced using the DEEP2 IDL pipeline 41 galaxies with S/N 15 luminosities: 20.5 M r (SDSS) 15.0 mag For these galaxies we can measure dispersions down to 15 km s-1 Velocity dispersions measured from CaT absorption lines (CaII: 8498, 8542 and 8662 - weak dependence on metallicity) Analysis of red setup: 7500A - 9000A, CaT analysis (Kourkchi et al. 2010, in prep) 27. Measurements from the CaT region: not trivial! SKY LINES are redshifted to CaT Velocity Dispersions the data 28. pPXF: Cappellari & Emsellem (2004) - templates selected from the Indo-US stellar library (+ three DEIMOS templates) - radial velocity and dispersion determined simultaneously by minimising the X2 - uses multiple weighted stellar templates (~50-80) and nds best t solution - no need to do simulation before any measurement - less sensitive to S/N ratio than other methods - results agree well with Cody et al. (2008) for S/N >15 FXCOR: Tonry & Davis (1979) - simulation needed before any measurement - to check cross-correlation - very sensitive to low S/N ratio spectra - need to use many stellar templates in order to get reliable results Velocity Dispersions analysis 29. pPXF: Cappellari & Emsellem (2004) - THE DETAILS - pPFX works in pixel space and uses Guass-Hermite series to extract the radial velocity and dispersion simultaneously by minimising the X2 - galaxy spectrum and template spectra are rebinned linearly in wavelength x = ln () - model spectrum obtained by convolving the template and a broadening function. - for low S/N pPXF supresses the noise effects in the solution Errors and Uncertainties (i) statistical error - simulated galaxy spectra with variable S/N, errors due to random noise (ii) template mismatch - measurement limited to CaT region Velocity Dispersions analysis 30. Luminosity: SDSS Mr log(velocitydispersion) Matkovic et al. (2005) KPNO/WIYN Hydra bre spectroscopy Mgb and H lines used to measure dispersions (stronger metallicity dependence) RESULTS: Faber-Jackson Relation ( L ) 31. Luminosity: SDSS Mr log(velocitydispersion) Cody et al. (2008) KPNO/WIYN Hydra bre spectroscopy of early type galaxies 20.6 < MR < -15.7 Mgb and H lines used to measure dispersions 60% galaxies have S/N 0.5 deg = 1.29 0.29 RESULTS: Faber-Jackson Relation ( L ) 32. RESULTS: Faber-Jackson Relation ( L ) Luminosity: SDSS Mr log(velocitydispersion) S/N < 15 Kourkchi et al. (2010) - in prep PhD Thesis 33. RESULTS: Faber-Jackson Relation ( L ) Luminosity: SDSS Mr log(velocitydispersion) = 2.73 0.06 for DEIMOS galaxies with S/N > 15 = 2.62 0.03 for K10 + M05 samples = 2.45 0.02 for K10 + M05 +C08 samples 34. RESULTS: Faber-Jackson Relation ( L ) Science Questions: does the relation atten? Is the scatter at the faint end dependent on other parameters? i.e. Sersic index? or eff? (Graham & Guzman 2003) Are deviations from Srsic proles due to distinct types of early type galaxy? (Kormendy et al. 2009) missing light at small radii scouring by binary black holes extra light at small radii starbursts following dissipative mergers rotation? (Emsellem et al. 2007) 35. STRUCTURAL PARAMETER ANALYSIS http://keckobservatory.org/ 36. THE STRUCTURAL PARAMETERS CATALOGUE ~ 10,000 galaxies in 25 Coma elds. All galaxies with brighter than 24.5 mag arcsec2 SExtractor source detection, photometry and basic geometric parameters (inc. S/G class) GIM2D Single Srsic ts (n), bulge-disk parameters GALFIT Single Srsic ts (n), effective radii (re), surface brightesses (), bulge-disk parameters Error and completeness (magnitude and size) analysis from GEMS simulations. Available to the astronomical community at ASTRO-WISE and MAST. Complements two other HST surveys: Based on F814W ACS images: Hoyos et al (2010), Mark den Brok - PhD STAGES: Abell 901/2 at redshift z~ 0.165 (Grey et al. 2009) GEMS: 900 arcmin2 region within the Extended Chandra DFS (Rix et al. 2004) 37. RESULTS: Structural Analysis Kourkchi et al. (2010) in prep 38. RESULTS: Structural Analysis Kourkchi et al. (2010) in prep typical Reff are less than 1.6 kpc 39. RESULTS: Structural Analysis Kourkchi et al. (2010) in prep 40. Work in Progress Non-standard setup - wavelength calibration tricky! (optical model results in ~45 error) DEIMOS optimized for red setup. Low throughput restricts us to ~5000 - 6500 (ie. H, Mg, Fe) (at least for most galaxies) AIM: combine with velocity dispersion results and compare with previous work (eg. Matkovic & Guzman 2005) Analysis of blue setup: 3900A - 6700A, Line-strength indices (Karick et al. 2010, in prep) 41. Conclusion The ACS Coma Cluster Treasury Survey. Science Highlights: UCDs, LSB galaxies and galaxy stripping. Keck/DEIMOS observations of ~200 conrmed and likely cluster members Accurate velocity dispersions for ~40 cluster galaxies down to 20 kms-1 = 2.73 0.06 for 38 dwarf galaxies with S/N >15 Fundamental Plane: investigating the dependence on structural parameters. Structural Parameters Catalogue: Available mid-2010 on ASTRO-WISE and MAST Future Work: Detailed structural parameter study of SPC sub-samples 42. ...THANKS Keck/DEIMOS spectroscopy of Coma Cluster UCDs/IGCs (with Michael Gregg & Michael West) UV/Optical properties of Fornax Cluster galaxies (with Michael Gregg & Soo-Chang Rey) Magellan/IMACS spectroscopy of ~60 Fornax Cluster UCDs/GCs (with Michael Gregg & Marla Geha) CTIO/ugriz imaing of Fornax Cluster galaxies and UCDs (with Michael Gregg & Michael Drinkwater) Keck/HIRES+LGSAO observations of bright M31 Globular Clusters (with Michael Gregg) 6dF spectroscopy of Fornax Cluster galaxies - E+As? (with Michael Drinkwater)