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Blakeslee, John P.,Cho, Hyejeon,Peng, Eric W.,Ferrarese, Laura,Jordá,n, André,s,Martel, André,R. IOP Publishing 2012 The Astrophysical journal Vol.746 No.1
<P>We combine new Wide Field Camera 3 IR Channel (WFC3/IR) F160W (H-160) imaging data for NGC 1399, the central galaxy in the Fornax cluster, with archival F475W (g(475)), F606W (V-606), F814W (I-814), and F850LP (z.(850)) optical data from the Advanced Camera for Surveys (ACS). The purely optical g(475)-I-814, V-606-I-814, and g(475)-z(850) colors of NGC 1399's rich globular cluster (GC) system exhibit clear bimodality, at least for magnitudes I-814 > 21.5. The optical-IR I-814-H-160 color distribution appears unimodal, and this impression is confirmed by mixture modeling analysis. The V-606-H-160 colors show marginal evidence for bimodality, consistent with bimodality in V-606-I-814 and unimodality in I-814-H-160. If bimodality is imposed for I-814-H-160 with a double Gaussian model, the preferred blue/red split differs from that for optical colors; these 'differing bimodalities' mean that the optical and optical-IR colors cannot both be linearly proportional to metallicity. Consistent with the differing color distributions, the dependence of I-814-H-160 on g(475)-I-814 for the matched GC sample is significantly nonlinear, with an inflection point near the trough in the g(475)-I-814 color distribution; the result is similar for the I-814-H-160 dependence on g(475)-z(850) colors taken from the ACS Fornax Cluster Survey. These g(475)-z(850) colors have been calibrated empirically against metallicity; applying this calibration yields a continuous, skewed, but single-peaked metallicity distribution. Taken together, these results indicate that nonlinear color-metallicity relations play an important role in shaping the observed bimodal distributions of optical colors in extragalactic GC systems.</P>
Paudel, Sanjaya,Smith, Rory,Duc, Pierre-Alain,Cô,té,, Patrick,Cuillandre, Jean-Charles,Ferrarese, Laura,Blakeslee, John P.,Boselli, Alessandro,Cantiello, Michele,Gwyn, S. D. J.,Guhathakurta American Astronomical Society 2017 The Astrophysical Journal Vol.834 No.1
<P>The Next Generation Virgo Cluster Survey is a deep (with a 2 sigma detection limit mu g = 29 mag arcsec(-2) in the g-band) optical panchromatic survey targeting the Virgo cluster from its core to virial radius, for a total areal coverage of 104 square degrees. As such, the survey is well suited for the study of galaxies' outskirts, haloes, and low surface brightness features that arise from dynamical interactions within the cluster environment. We report the discovery of extremely faint (mu g > 25 mag arcsec(-2)) shells in three Virgo cluster early-type dwarf galaxies: VCC. 1361, VCC. 1447, and VCC. 1668. Among them, VCC. 1447 has an absolute magnitude Mg = -11.71 mag and is the least massive galaxy with a shell system discovered to date. We present a detailed study of these low surface brightness features. We detect between three and four shells in each of our galaxies. Within the uncertainties, we find no evidence of a color difference between the galaxy main body and shell features. The observed arcs of the shells are located up to several effective radii of the galaxies. We further explore the origin of these low surface brightness features with the help of idealized numerical simulations. We find that a near equal mass merger is best able to reproduce the main properties of the shells, including their quite symmetric appearance and their alignment along the major axis of the galaxy. The simulations provide support for a formation scenario in which a recent merger, between two near-equal mass, gas-free dwarf galaxies, forms the observed shell systems.</P>
Gessica Sala,Alessandro Arosio,Elisa Conti,Simone Beretta,Christian Lunetta,Nilo Riva,Carlo Ferrarese,Lucio Tremolizzo 대한정신약물학회 2019 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.17 No.3
Objective: Until recently, riluzole was the only drug licensed for amyotrophic lateral sclerosis (ALS). In spite of its efficacy, the mechanism of action remains elusive, and both blocking of glutamate release and antioxidant properties have been postulated. Here we characterized human SH-SY5Y neuroblastoma cell lines, taking advantage of their insensitivity to excitotoxic insults, in order to selectively assess the presence of a direct antioxidant effect of riluzole. Methods: SH-SY5Y cells, either parental or overexpressing the G93A SOD1 mutation, were exposed for 24 hours to the selected stimuli. Results: Riluzole (1‒10 M) was able to counteract the effects of H2O2 exposure (200 M/24 hr), limiting both cell death and whole-cell reactive oxygen species (ROS) increase. The same experiments were repeated using SH-SY5Y cells carrying the familial ALS-related G93A-SOD1 mutation and constitutively expressing two-fold increased whole-cell ROS levels with respect to wild-type cells: riluzole was ineffective in this paradigm. Analogously, riluzole was ineffective in preventing cell death induced by exposing SH-SY5Y cells to 3-morpholino-sydnonimine (SIN-1, 1.5 mM/24 hr), a reactive nitrogen species (RNS) donor. Conclusion: Our data support a direct antioxidant action of riluzole. Furthermore, the lack of efficacy of riluzole observed in the SOD1 cell model mirrors the lack of efficacy already demonstrated in cognate mouse models of ALS, plausibly reflecting differences in the underlying pathogenic mechanisms. Finally, riluzole inefficacy against nitrosative stress might support the idea that a combined therapeutic intervention may result more effective in ALS patients, as in the case of co-administration of edaravone, a drug known to reduce RNS.
The sensitivity of harassment to orbit: mass loss from early-type dwarfs in galaxy clusters
Smith, R.,Sá,nchez-Janssen, R.,Beasley, M. A.,Candlish, G. N.,Gibson, B. K.,Puzia, T. H.,Janz, J.,Knebe, A.,Aguerri, J. A. L.,Lisker, T.,Hensler, G.,Fellhauer, M.,Ferrarese, L.,Yi, S. K. Oxford University Press 2015 Monthly notices of the Royal Astronomical Society Vol.454 No.3