316 research outputs found

    Calibration of AGN Reverberation Distance Measurements

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    In Yoshii et al. (2014), we described a new method for measuring extragalactic distances based on dust reverberation in active galactic nuclei (AGNs), and we validated our new method with Cepheid variable stars. In this paper, we validate our new method with Type Ia supernovae (SNe Ia) which occurred in two of the AGN host galaxies during our AGN monitoring program: SN 2004bd in NGC 3786 and SN 2008ec in NGC 7469. Their multicolor light curves were observed and analyzed using two widely accepted methods for measuring SN distances, and the distance moduli derived are μ=33.47±0.15\mu=33.47\pm 0.15 for SN 2004bd and 33.83±0.0733.83\pm 0.07 for SN 2008ec. These results are used to obtain independently the distance measurement calibration factor, gg. The gg value obtained from the SN Ia discussed in this paper is gSN=10.61±0.50g_{\rm SN} = 10.61\pm 0.50 which matches, within the range of 1σ\sigma uncertainty, gDUST=10.60g_{\rm DUST} = 10.60, previously calculated ab initio in Yoshii et al. (2014). Having validated our new method for measuring extragalactic distances, we use our new method to calibrate reverberation distances derived from variations of Hβ\beta emission in the AGN broad line region (BLR), extending the Hubble diagram to z0.3z\approx 0.3 where distinguishing between cosmologies is becoming possible.Comment: Astrophysical Journal Letters accepte

    The Infrared Cloud Monitor for the MAGNUM Robotic Telescope at Haleakala

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    We present the most successful infrared cloud monitor for a robotic telescope. This system was originally developed for the MAGNUM 2-m telescope, which has been achieving unmanned and automated monitoring observation of active galactic nuclei at Haleakala on the Hawaiian island of Maui since 2001. Using a thermal imager and two aspherical mirrors, it at once sees almost the whole sky at a wavelength of λ10μm\lambda\sim 10\mu{\rm m}. Its outdoor part is weather-proof and is totally maintenance-free. The images obtained every one or two minutes are analysed immediately into several ranks of weather condition, from which our automated observing system not only decides to open or close the dome, but also selects what types of observations should be done. The whole-sky data accumulated over four years show that 50-60 % of all nights are photometric, and about 75 % are observable with respect to cloud condition at Haleakala. Many copies of this system are now used all over the world such as Mauna Kea in Hawaii, Atacama in Chile, and Okayama and Kiso in Japan.Comment: 18 pages, 15 figures, 7 tables, accepted for publication in PAS

    The Optical/Near-Infrared Light Curves of SN 2002ap for the First 1.5 Years after Discovery

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    Late-time BVRIJHK photometry of the peculiar Type Ic SN 2002ap, taken between 2002 June 12 and 2003 August 29 with the MAGNUM telescope, is presented. The light curve decline rate is derived in each band and the color evolution is studied through comparison with nebular spectra and with SN 1998bw. Using the photometry, the OIR bolometric light curve is built, extending from before light maximum to day 580 after explosion. The light curve has a late-time shape strikingly similar to that of the hypernova SN 1998bw. The decline rate changes from 0.018 mag/day between day 130 and 230 to 0.014 mag/day between day 270 and 580. To reproduce the late-time light curve, a dense core must be added to the 1-D hypernova model that best fits the early-time observations, bringing the ejecta mass from 2.5 Msun to 3 Msun without much change in the kinetic energy, which is 4 times 10^51 ergs. This is similar to the case of other hypernovae and suggests asymmetry. A large H-band bump developed in the spectral energy distribution after about day 300, probably caused by strong [Si I] 1.646 micron and 1.608 micron emissions. The near-infrared flux contribution increased simultaneously from 50% at day 580. The near-infrared light curves were compared with those of other Type Ib/c supernovae, among which SN 1983I seems similar to SN 2002ap both in the near-infrared and in the optical.Comment: 24pages, 9 figures, ApJ in press (10 June 2006, v644 1 issue). Acknowledgements update

    Recent Advances in Fluorescent Labeling Techniques for Fluorescence Microscopy

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    Tremendous progress in recent computer-controlled systems for fluorescence and laser-confocal microscopy has provided us with powerful tools to visualize and analyze molecular events in the cells. Various fluorescent staining and labeling techniques have also been developed to be used with these powerful instruments. Fluorescent proteins such as green fluorescent protein (GFP) allow us to directly label particular proteins of interest in living cells. This technique has been extended over a large area of cell biology, and a variety of fluorescent protein-derived techniques have been developed to visualize the functions and conditions of the molecules within living cells. In this review, we summarize the techniques for fluorescent staining and labeling for recent fluorescence microscopy

    The Efficacy of Mirabegron for the Relief of Ureteral Stent-Related Symptoms

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    To investigate the efficacy of mirabegron for lower urinary tract symptoms in patients with an indwelling ureteral stent after ureterorenoscopic lithotripsy. This was a prospective follow-up study of 76 patients with stent-related symptoms (SRSs). Patients with upper urinary calculi who were pre-stented for > 2 weeks before lithotripsy were examined for the presence of SRSs by tests including the International Prostate Symptom Score (IPSS), OAB Symptom Score (OABSS), and urinary bother and pain measured by a Visual Analogue Scale (VAS) before lithotripsy. Mirabegron (50 mg/day) was prescribed post-lithotripsy for 2 weeks. SRSs were assessed at the time of stent removal. The IPSS scores improved significantly from 16.2 to 14.3 (p<0.001) and the IPSS-QoL scores decreased significantly from 5.0 to 4.6 (p=0.012). The OABSS scores improved significantly from 7.7 to 6.8 (p=0.006), and the urinary urgency scores (OABSS-Q3) decreased significantly from 3.24 to 2.68 (p<0.001). The number of nocturia episodes decreased significantly from 2.5 to 2.2 (p=0.045). Urinary bother and pain assessed by the VAS declined from 4.2 and 3.1 to 3.8 (p=0.15) and 2.5 (p=0.075), respectively. Mirabegron significantly improved SRSs and the number of nocturia episodes due to a ureteral stent

    First Detection of Near-Infrared Intraday Variations in the Seyfert 1 Nucleus NGC4395

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    We carried out a one-night optical V and near-infrared JHK monitoring observation of the least luminous Seyfert 1 galaxy, NGC4395, on 2004 May 1, and detected for the first time the intraday flux variations in the J and H bands, while such variation was not clearly seen for the K band. The detected J and H variations are synchronized with the flux variation in the V band, which indicates that the intraday-variable component of near-infrared continuum emission of the NGC4395 nucleus is an extension of power-law continuum emission to the near-infrared and originates in an outer region of the central accretion disk. On the other hand, from our regular program of long-term optical BVI and near-infrared JHK monitoring observation of NGC4395 from 2004 February 12 until 2005 January 22, we found large flux variations in all the bands on time scales of days to months. The optical BVI variations are almost synchronized with each other, but not completely with the near-infrared JHK variations. The color temperature of the near-infrared variable component is estimated to be T=1320-1710 K, in agreement with thermal emission from hot dust tori in active galactic nuclei (AGNs). We therefore conclude that the near-infrared variation consists of two components having different time scales, so that a small K-flux variation on a time scale of a few hours would possibly be veiled by large variation of thermal dust emission on a time scale of days.Comment: 4 pages including figures, accepted for publication in ApJ

    Variation of Inner Radius of Dust Torus in NGC4151

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    The long-term optical and near infrared monitoring observations for a type 1 act ive galactic nucleus NGC 4151 were carried out for six years from 2001 to 2006 b y using the MAGNUM telescope, and delayed response of flux variations in the K(2.2μm)K(2.2\mu m) band to those in the V(0.55μm)V(0.55\mu m) band was clearly detected. Based on cross correlation analysis, we precisely measured a lag time Δt\Delta t for eight separate periods, and we found that Δt\Delta t is not constant changing be tween 30 and 70 days during the monitoring period. Since Δt\Delta t is the ligh t travel time from the central energy source out to the surrounding dust torus, this is the first convincing evidence that the inner radius of dust torus did ch ange in an individual AGN. In order to relate such a change of Δt\Delta t with a change of AGN luminosity LL, we presented a method of taking an average of th e observed VV-band fluxes that corresponds to the measured value of Δt\Delta t, and we found that the time-changing track of NGC 4151 in the Δt\Delta t versus LL diagram during the monitoring period deviates from the relation of ΔtL0.5\Delta t \propto L^{0.5} expected from dust reverberation. This result, combined with t he elapsed time from period to period for which Δt\Delta t was measured, indicat es that the timescale of dust formation is about one year, which should be taken into account as a new constraint in future studies of dust evolution in AGNs.Comment: 5 pages, 3 figures, To appear in the ApJ Lette
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