The MASTER-II network of robotic optical telescopes. First results

The main stages in the creation of the Russian segment of the MASTER network of robotic telescopes is described. This network is designed for studies of the prompt optical emission of gammaray bursts (GRBs; optical emission synchronous with the gamma-ray radiation) and surveys of the sky aimed at discovering uncataloged objects and photometric studies for various programs. The first results obtained by the network, during its construction and immediately after its completion in December 2010, are presented. Eighty-nine alert pointings at GRBs (in most cases, being the first ground telescopes to point at the GRBs) were made from September 2006 through July 2011. The MASTER network holds first place in the world in terms of the total number of first pointings, and currently more than half of first pointings at GRBs by ground telescopes are made by the MASTER network. Photometric light curves of GRB 091020, GRB 091127, GRB 100901A, GRB 100906A, GRB 10925A, GRB 110106A, GRB 110422A, and GRB 110530A are presented. It is especially important that prompt emission was observed for GRB 100901A and GRB 100906A, and thar GRB 091127, GRB 110422A, and GRB 110106A were observed from the first seconds in two polarizations. Very-wide-field cameras carried out synchronous observations of the prompt emission of GRB 081102, GRB 081130B, GRB 090305B, GRB 090320B, GRB 090328, and GRB 090424. Discoveries of Type Ia supernovae are ongoing (among them the brightest supernova in 2009): 2008gy, 2009nr, 2010V, and others. In all, photometry of 387 supernovae has been carried out, 43 of which were either discovered or first observed with MASTER telescopes; more than half of these are Type Ia supernovae. Photometric studies of the open clusters NGC 7129 and NGC 7142 have been conducted, leading to the discovery of 38 variable stars. Sixty-nine optical transients have been discovered. © 2013 Pleiades Publishing, Ltd

Immunoassay for troponin I using a glassy carbon electrode modified with a hybrid film consisting of graphene and multiwalled carbon nanotubes and decorated with platinum nanoparticles

This article describes a bioelectrode for the determination of human cardiac troponin-I (cTnI). A glassy carbon electrode was coated with a hybrid film of graphene and multiwalled carbon nanotube (G-MWCNT) and modified with platinum nanoparticles (Pt NPs) that were capped with mercaptopropionic acid. The PtNPs were anchored on the G-MWCNT hybrid film via the cross-linker 1-pyrenemethylamine and subsequently functionalized with antibody against troponin (anti-cTnI). The bioelectrode was characterized by transmission electron microscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The performance of the immunoelectrode was investigated by electrochemical impedance spectroscopy, and response was fit to Randle's equivalent circuit model. The charge transfer resistance (R-et) at a.c. frequencies of < 1 Hz is found to be a viable sensing parameter. The dissociation constant of the immunoreaction between surface immobilized anti-cTnI and the analyte cTnI is 0.29 nM (with a Hill coefficient of 0.23), this indicating a negative cooperativity and high binding affinity of cTnI for anti-cTnI on the electrode surface. The EIS response is linear in the 1.0 pg mL(-1) to 10 ng mL(-1) concentration range, and the R-et sensitivity is 145.5 a"broken vertical bar cm(2) per decade

2014 WZ120

International audienceAvailable from the Minor Planet Center

2014 WZ120

International audienceAvailable from the Minor Planet Center

AWAKENING OF THE HIGH-REDSHIFT BLAZAR CGRaBS J0809+5341

CGRaBS J0809+5341, a high redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by $\sim$5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of -30.5 mag, making it one of the brightest quasars in the Universe. This optical flaring triggered us to carry out observations during the decaying part of the flare covering a wide energy range using the {\it Nuclear Spectroscopic Telescope Array}, {\it Swift}, and ground based optical facilities. For the first time, the source is detected in $\gamma$-rays by the Large Area Telescope onboard the {\it Fermi Gamma-Ray Space Telescope}. A high optical polarization of $\sim$10\% is also observed. Using the Sloan Digital Sky Survey spectrum, accretion disk luminosity and black hole mass are estimated as $1.5 \times 10^{45}$ erg s$^{-1}$ and $10^{8.4}~M_{\odot}$ respectively. Using a single zone leptonic emission model, we reproduce the spectral energy distribution of the source during the flaring activity. This analysis suggests that the emission region is probably located outside the broad line region, and the jet becomes radiatively efficient. We also show that the overall properties of CGRaBS J0809+5341 seems not to be in agreement with the general properties observed in high redshift blazars up to now.Comment: 37 pages, 6 figures, 5 tables, to appear in The Astrophysical Journa