Browsing by Author "Yoon, S.-J."

Now showing items 1-8 of 8

    • Better age estimation using ultraviolet-optical colours : Breaking the age-metallicity degeneracy 

      Kaviraj, S.; Rey, S.-C.; Yoon, S.-J.; Yi, S.K.; Rich, R.M. (2007-10-01)
      We demonstrate that the combination of GALEX ultraviolet (UV) photometry in the far-UV (FUV; ~1530 Å) and near-UV (NUV; ~2310 Å) passbands with optical photometry in the standard U, B, V, R, I filters can efficiently break ...

    • The effect of environment on the ultraviolet color-magnitude relation of early-type galaxies 

      Schawinski, K.; Kaviraj, S.; Khochfar, S.; Yoon, S.-J.; Yi, S.K.; Lee, Y.-W.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Milliard, B.; Barlow, T.; Conrow, T.; Forster, K.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Seibert, M.; Small, T.; Wyder, T.; Neff, S.; Schiminovich, D.; Blanchi, L.; Heckman, T.; Szalay, A.; Madore, B.; Rich, R.M. (2007-12-01)
      We use GALEX near-UV (NUV ) photometry of a sample of early-type galaxies selected in the SDSS (Sloan Digital Sky Survey) to study the UV color-magnitude relation (CMR). NUV - r color is an excellent tracer of even small ...

    • Galaxy evolution explorer ultraviolet color-magnitude relations and evidence of recent star formation in early-type galaxies 

      Yi, S.K.; Yoon, S.-J.; Lee, Y.-W.; Ree, C.H.; Sohn, Y.-J.; Rey, S.-C.; Rhee, J.; Byun, Y.-I.; Kim, S.-W.; Kaviraj, S.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Malina, R.; Milliard, B.; Rich, R.M.; Salim, S.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Small, T.; Barlow, T.; Forster, K.; Wyder, T.K.; Lee, J.-W.; Bianchi, L.; Heckman, T.M.; Szalay, A.S.; Jee, M.J.; Jelinsky, P.; Siegmund, O.; Welsh, B.; Madore, B.F.; Neff, S.; Schiminovich, D. (2005-01-20)
      We have used the Galaxy Evolution Explorer UV photometric data to construct a first near-UV (NUV) color-magnitude relation (CMR) for the galaxies preclassified as early-type by Sloan Digital Sky Survey studies. The NUV CMR ...

    • Globular clusters as probes of galaxy evolution : NGC 5128 

      Yi, S.K.; Kaviraj, S.; Yoon, S.-J.; Peng, E.; Ford, H. (2004-04-21)
      We present the results of our analysis of the photometric data of globular clusters in the elliptical galaxy NGC 5128 (Cen A). We show that the integrated colour U - B can be an effective metallicity indicator for simple ...

    • The look-back time evolution of far-ultraviolet flux from the brightest cluster elliptical galaxies at z <0.2 

      Ree, C.H.; Lee, Y.-W.; Yi, S.K.; Yoon, S.-J.; Sohn, Y.-J.; Rhee, J.; Sheen, Y.-K.; Rich, R.M.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Milliard, B.; Kaviraj, S.; Schawinski, K.; Rey, S.-C.; Seibert, M.; Wyder, T.K.; Barlow, T.A.; Forster, K.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Small, T.; Bianchi, L.; Heckman, T.M.; Szalay, A.S.; Madore, B.F.; Neff, S.G.; Schiminovich, D.; Welsh, B.Y. (2007-12-01)
      We present the GALEXUV photometry of the elliptical galaxies in Abell clusters at moderate redshifts (z <0.2) for the study of the look-back time evolution of the UV upturn phenomenon. The brightest elliptical galaxies (M ...

    • On the globular cluster formation history of NGC 5128 

      Kaviraj, S.; Ferreras, I.; Yoon, S.-J.; Yi, S.K. (2005-09-01)
      We deduce the globular cluster formation history of the nearby elliptical galaxy, NGC 5128, by using a chemical enrichment model to accurately reproduce its observed metallicity distribution function (MDF). We derive the ...

    • UV bright globular clusters in M87 : More evidence for super-He-rich stellar populations? 

      Kaviraj, S.; Sohn, S.T.; O'Connell, R.W.; Yoon, S.-J.; Lee, Y.W.; Yi, S.K. (2007-05-01)
      We study the ultraviolet (UV) and optical properties of 38 massive globular clusters (GCs) in the Virgo elliptical, M87, imaged using the STIS and WFPC2 instruments onboard the Hubble Space Telescope. The majority of these ...

    • UV-optical colors as probes of early-type galaxy evolution 

      Kaviraj, S.; Schawinski, K.; Devriendt, J.E.G.; Ferreras, I.; Khochfar, S.; Yoon, S.-J.; Yi, S.K.; Lee, Y.-W.; Deharveng, J.-M.; Boselli, A.; Donas, J.; Milliard, B.; Barlow, T.; Conrow, T.; Forster, K.; Friedman, P.G.; Martin, D.C.; Morrissey, P.; Seibert, M.; Small, T.; Wyder, T.; Neff, S.; Schiminovich, D.; Bianchi, L.; Heckman, T.; Szalay, A.; Madore, B.; Rich, R.M. (2007-12-01)
      We have studied ∼2100 early-type galaxies in the SDSS DR3 which have been detected by the GALEX Medium Imaging Survey (MIS), in the redshift range O <z <0.1.1. Combining GALEXUV photometry with corollary optical data from ...