Infrared Imaging of the Gravitational Lens PG 1115+080 with the Subaru Telescope

We present high spatial resolution images of the gravitational-lens system PG 1115+080 taken with the near-infrared camera (CISCO) on the Subaru telescope. The FWHM of the combined image is $0.''32$ in the $K'$-band, yielding spatial resolution of $0.''14$ after a deconvolution procedure. This is a first detection of an extended emission adjacent to the A1/A2 components, indicating the presence of a fairly bright emission region with a characteristic angular radius of $\sim$ 5 mas (40 pc). The near-infrared image of the Einstein ring was extracted in both the $J$ and $K'$ bands. The $J-K'$ color is found to be significantly redder than that of a synthetic model galaxy with an age of 3 Gyr, the age of the universe at the quasar redshift.Comment: 11 pages, 6 figures. Accepted for publication in PASJ(2000

Discovery of the VHE gamma-ray source HESS J1641-463

A new TeV source, HESS J1641-463, has been serendipitously discovered in the Galactic plane by the High Energy Stereoscopic System (H.E.S.S.) at a significance level of 8.6 standard deviations. The observations of HESS J1641-463 were performed between 2004 and 2011 and the source has a moderate flux level of 1.7% of the Crab Nebula flux at E > 1 TeV. HESS J1641-463 has a rather hard photon index of 1.99 +- 0.13_stat +- 0.20_sys. HESS J1641-463 is positionally coincident with the radio supernova remnant SNR G338.5+0.1, but no clear X-ray counterpart has been found in archival Chandra observations of the region. Different possible VHE production scenarios will be discussed in this contribution.Comment: 5 pages, 5 figures, 2012 Fermi Symposium proceedings - eConf C12102

Near-infrared emission-line galaxies in the Hubble Deep Field North

We present the 2.12~$\mu$m narrow-band image of the Hubble Deep Field North taken with the near-infrared camera (CISCO) on the Subaru telescope. Among five targets whose H$\alpha$ or [O~{\sc iii}] emission lines are redshifted into our narrow-band range expected from their spectroscopic redshift, four of them have strong emission lines, especially for the two [O~{\sc iii}] emission-line objects. The remaining one target shows no H$\alpha$ emission in spite of its bright rest-UV luminosity, indicating that this object is already under the post-starburst phase. The volume-averaged $SFR$ derived from the detected two H$\alpha$ emission is roughly consistent with that evaluated from the rest-UV continuum.Comment: 12 pages, 7 figures. Accepted for publication in PASJ(2000

Statistical Analysis of a Semilinear Hyperbolic System Advected by a White in Time Random Velocity Field

We study a system of semilinear hyperbolic equations passively advected by smooth white noise in time random velocity fields. Such a system arises in modeling non-premixed isothermal turbulent flames under single-step kinetics of fuel and oxidizer. We derive closed equations for one-point and multi-point probability distribution functions (PDFs) and closed form analytical formulas for the one point PDF function, as well as the two-point PDF function under homogeneity and isotropy. Exact solution formulas allows us to analyze the ensemble averaged fuel/oxidizer concentrations and the motion of their level curves. We recover the empirical formulas of combustion in the thin reaction zone limit and show that these approximate formulas can either underestimate or overestimate average concentrations when reaction zone is not tending to zero. We show that the averaged reaction rate slows down locally in space due to random advection induced diffusion; and that the level curves of ensemble averaged concentration undergo diffusion about mean locations.Comment: 18 page

Status and Plans for the Array Control and Data Acquisition System of the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is the next-generation atmospheric Cherenkov gamma-ray observatory. CTA will consist of two installations, one in the northern, and the other in the southern hemisphere, containing tens of telescopes of different sizes. The CTA performance requirements and the inherent complexity associated with the operation, control and monitoring of such a large distributed multi-telescope array leads to new challenges in the field of the gamma-ray astronomy. The ACTL (array control and data acquisition) system will consist of the hardware and software that is necessary to control and monitor the CTA arrays, as well as to time-stamp, read-out, filter and store -at aggregated rates of few GB/s- the scientific data. The ACTL system must be flexible enough to permit the simultaneous automatic operation of multiple sub-arrays of telescopes with a minimum personnel effort on site. One of the challenges of the system is to provide a reliable integration of the control of a large and heterogeneous set of devices. Moreover, the system is required to be ready to adapt the observation schedule, on timescales of a few tens of seconds, to account for changing environmental conditions or to prioritize incoming scientific alerts from time-critical transient phenomena such as gamma ray bursts. This contribution provides a summary of the main design choices and plans for building the ACTL system.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

MWL observations of VHE blazars in 2006

In 2006 the MAGIC telescope observed the well known very high energy (VHE, > 80 GeV) blazars Mrk 421 and Mrk 501 in the course of multi-wavelength campaigns, comprising measurements in the optical, X-ray and VHE regime. MAGIC performed additional snapshot observations on Mrk 421 around the MWL campaigns and detected the source each night with high significance, establishing once more flux variability on nightly scales for this object. For certain nights, the integral flux exceeded the one of Crab significantly, whereas the truly simultaneous observations have been conducted in a rather low flux state. The MAGIC observations contemporaneous to XMM-Newton revealed clear intra-night variability. No significant correlation between the spectral index and the flux could be found for the nine days of observations. The VHE observations of Mrk 501 have been conducted during one of the lowest flux states ever measured by MAGIC for this object. The VHE and optical light curves do not show significant variability, whereas the flux in X-rays increased by about 50 %. In this contribution, the results of the MAGIC observations will be presented in detail.Comment: Contribution to the 31st ICRC, Lodz, Poland, July 200