Prediction of Clinical Response to Arabinosylcytosine (Ara-C) Therapy

Stellar and dust properties of local elliptical galaxies: clues to the onset of nuclear activity

“…Specifically, we find that the two galaxy subgroups have essentially indistinguishable total optical and near-infrared luminosities, central stellar velocity dispersions, and luminosity-weighted mean stellar ages and metallicities on nuclear ( < ∼ 300 pc) scales. The lack of young or intermediate-age stars in LINERs strongly rule out starburst and post-starburst models for the excitation of LINER-like emission, further strengthening the proposition that LINERs are lowluminosity AGNs (Ho 2008).…”

“…First, the SDSS sources have redshifts z ≈ 0.05−0.1, much more distant than the Palomar galaxies. As discussed by Ho (2008), aperture effects render the interpretation of LINER emission in distant galaxies somewhat problematic. Second, the stellar population analysis method of this paper differs from that used in the SDSS studies, and it is unclear if there are residual systematic discrepancies between the different methods.…”

“…Ho et al (2003) systematically investigated the stellar population of the emission-line nuclei in the Palomar survey and found that LINERs generally contain evolved stellar populations. Other evidence concerning the old ages of the nuclear stellar population in nearby low-luminosity AGNs is summarized in Ho (2008 Graves et al (2007) and Schawinski et al (2007) show that LINERs have a tendency to exhibit somewhat younger populations (by ∼3 Gyr) compared to inactive early-type galaxies devoid of emission lines. The differences between our results and those derived from SDSS can plausibly be attributed to a combination of several effects.…”

“…This includes the detection of broad Hα emission (Ho et al 1997b), some of which show double-peaked profiles (Ho et al 2000;Shields et al 2000;Barth et al 2001) or are polarized (Barth et al 1999a,b), ultraviolet variability (Maoz et al 2005), compact X-ray cores (e.g., Ho et al 2001;Terashima & Wilson 2003), and compact radio cores (e.g., Nagar et al 2005). Ho (2008) suggests that nearly all LINERs are genuine AGNs with low accretion rates.…”

“…However, the majority of SMBHs in nearby ellipticals are not very active. In the Palomar spectroscopic survey of nearby galaxies (Ho et al 1995(Ho et al , 1997a, only about 50% of the ellipticals show detectable emission-line nuclei, most of which (∼87%) are classified as low-ionization nuclear emission-line regions (LINERs; Heckman 1980; see Ho 2008, for a review).…”