We present early phase observations in optical and near-infrared wavelengths for the extremely luminous Type Ia supernova (SN Ia) 2009dc. The decline rate of the light curve is DELTAm{sub 15}(B) = ...0.65 +- 0.03, which is one of the slowest among SNe Ia. The peak V-band absolute magnitude is estimated to be M{sub V} = -19.90 +- 0.15 mag if no host extinction is assumed. It reaches M{sub V} = -20.19 +- 0.19 mag if we assume the host extinction of A{sub V} = 0.29 mag. SN 2009dc belongs to the most luminous class of SNe Ia, like SNe 2003fg and 2006gz. Our JHK{sub s} -band photometry shows that this SN is also one of the most luminous SNe Ia in near-infrared wavelengths. We estimate the ejected {sup 56}Ni mass of 1.2 +- 0.3 M{sub sun} for the no host extinction case (and of 1.6 +- 0.4 M{sub sun} for the host extinction of A{sub V} = 0.29 mag). The C II lambda6580 absorption line remains visible until a week after the maximum brightness, in contrast to its early disappearance in SN 2006gz. The line velocity of Si II lambda6355 is about 8000 km s{sup -1} around the maximum, being considerably slower than that of SN 2006gz. The velocity of the C II line is similar to or slightly less than that of the Si II line around the maximum. The presence of the carbon line suggests that the thick unburned C+O layer remains after the explosion. Spectropolarimetric observations by Tanaka et al. indicate that the explosion is nearly spherical. These observational facts suggest that SN 2009dc is a super-Chandrasekhar mass SN Ia.
ABSTRACT We present simultaneous optical and near-infrared (NIR) polarimetric results for the black hole binary V404 Cyg spanning the duration of its seven-day-long optically brightest phase of its ...2015 June outburst. The simultaneous R- and Ks-band light curves showed almost the same temporal variation except for the isolated (∼30-minute duration) orphan Ks-band flare observed at MJD 57193.54. We did not find any significant temporal variation of polarization degree (PD) and position angle (PA) in both R and Ks bands throughout our observations, including the duration of the orphan NIR flare. We show that the observed PD and PA are predominantly interstellar in origin by comparing the V404 Cyg polarimetric results with those of the surrounding sources within the 7′ × 7′ field of view. The low intrinsic PD (less than a few percent) implies that the optical and NIR emissions are dominated by either disk or optically thick synchrotron emission, or both. We also present the broadband spectra of V404 Cyg during the orphan NIR flare and a relatively faint and steady state by including quasi-simultaneous Swift/XRT and INTEGRAL fluxes. By adopting a single-zone synchrotron plus inverse-Compton model as widely used in modeling of blazars, we constrained the parameters of a putative jet. Because the jet synchrotron component cannot exceed the Swift/XRT disk/corona flux, the cutoff Lorentz factor in the electron energy distribution is constrained to be <102, suggesting that particle acceleration is less efficient in this microquasar jet outburst compared to active galactic nucleus jets. We also suggest that the loading of the baryon component inside the jet is inevitable based on energetic arguments.
The Belle II experiment and the SuperKEKB collider are designed to operate under a higher luminosity compared to that of Belle for the improvement of rare <inline-formula> <tex-math ...notation="LaTeX">B </tex-math></inline-formula> meson decay study and new physics search. To break the bottleneck of bandwidth and to improve the stability in the operation of the Belle II data acquisition (DAQ) system, a new PCI-express-based readout system has been developed. The new system includes a PCI-express-based high-speed readout board (PCIe40), which was originally developed for the upgrades of the LHCb and ALICE experiments, the PCIe40 firmware, the slow control, and readout software running on a readout PC. The new readout system's commissioning with most of the Belle II subdetectors has been performed, and the readout upgrade is complete for the particle-identification detectors and the neutral kaon and muon detector in Belle II, which has been operating stably with the new system in the beam collision "physics runs." The results of the commissioning and the performance of the global DAQ operation will be reported.
The Belle II experiment is a new generation B-factory experiment at the upgraded accelerator SuperKEKB. The luminosity of the accelerator is expected to be more than 40 times higher than that of the ...previous KEKB, and the average Level 1 trigger rate is estimated to become up to 30 kHz with a total raw data size of ~ 1.1 Mbytes resulting in a data throughput of ≥ 30 Gbytes/sec. In order to manage this huge data flow, the Belle II DAQ system is designed to perform a multi-step data reduction using a large number of CPUs implemented in various DAQ components from the detector readout modules to the High Level Trigger farm. In this article, the design of the data flow and the architecture of the High Level Trigger farm in the Belle II DAQ system is reported.
We evaluated the effect of salinity on rice at the reproductive phase. From flag leaf stage to dough stage, potted rice plants were irrigated twice a week with saline water (0, 25, 50, 100, and 200 ...mM NaCl) at a volume of 1.5 times that of the soil. Photosynthesis and leaf biochemical constituents were measured at flowering (15 days after treatment establishment, DATE) and milking stage (25 DATE). Samples for grain dry matter and biochemical analysis were collected at milking (25 DATE) and dough (37 DATE) stages. Reduction in photosynthesis in the salinized plants depended not only on a reduction of available CO
2 by stomatal closure, but also on the cumulative effects of leaf water and osmotic potential, stomatal conductance, transpiration rate, relative leaf water content, and biochemical constituents such as photosynthetic pigments, soluble carbohydrates, and protein. The cumulative effects resulted in low concentrations of assimilates in the leaves. These low concentrations and poor translocation of assimilates from the source reduced grain dry matter. Grain growth was less sensitive to salinity at milking stage. This suggests that the plant is able to escape stress when the duration of salinity is short.
The occurrence of low-amplitude flux variations in blazars on hourly timescales, commonly known as microvariability, is still a widely debated subject in high-energy astrophysics. Several competing ...scenarios have been proposed to explain such occurrences, including various jet plasma instabilities leading to the formation of shocks, magnetic reconnection sites, and turbulence. In this Letter, we present the results of our detailed investigation of a prominent, five-hour-long optical microflare detected during the recent WEBT campaign on 2014 March 2-6 targeting the blazar 0716+714. After separating the flaring component from the underlying base emission continuum of the blazar, we find that the microflare is highly polarized, with the polarization degree ~(40-60)% + or - (2-10)% and the electric vector position angle ~(10-20)degrees + or - (1-8)degrees slightly misaligned with respect to the position angle of the radio jet. The microflare evolution in the (Q,U) Stokes parameter space exhibits a looping behavior with a counterclockwise rotation, meaning the polarization degree decreases with the flux (but is higher in the flux decaying phase), and an approximately stable polarization angle. The overall very high polarization degree of the flare, its symmetric flux rise and decay profiles, and also its structured evolution in the Q-U plane all imply that the observed flux variation corresponds to a single emission region characterized by a highly ordered magnetic field. As discussed in the paper, a small-scale but strong shock propagating within the outflow, and compressing a disordered magnetic field component, provides a natural, though not unique, interpretation of our findings.
We present a study of SN 2009js in NGC 918. Multi-band Kanata optical photometry covering the first ~120 days shows the source to be a Type IIP SN. Reddening is dominated by that due to our Galaxy. ...One-year-post-explosion photometry with the New Technology Telescope and a Subaru optical spectrum 16 days post-discovery both imply a good match with the well-studied subluminous SN 2005cs. The plateau-phase luminosity of SN 2009js and its plateau duration are more similar to the intermediate luminosity IIP SN 2008in. Thus, SN 2009js shares characteristics with both subluminous and intermediate luminosity supernovae (SNe). Its radioactive tail luminosity lies between SN 2005cs and SN 2008in, whereas its quasi-bolometric luminosity decline from peak to plateau (quantified by a newly defined parameter Delta logscriptL, which measures adiabatic cooling following shock breakout) is much smaller than both the others'. We estimate the ejected mass of super(56)Ni to be low (~0.007 M sub(middot in circle)). The SN explosion energy appears to have been small, similar to that of SN 2005cs. SN 2009js is the first subluminous SN IIP to be studied in the mid-infrared. It was serendipitously caught by Spitzer at very early times. In addition, it was detected by WISE 105 days later with a significant 4.6 mu m flux excess above the photosphere. The infrared excess luminosity relative to the photosphere is clearly smaller than that of SN 2004dj, which has been extensively studied in the mid-infrared. The excess may be tentatively assigned to heated dust with mass ~3 x 10 super(-5) M sub(middot in circle), or to CO fundamental emission as a precursor to dust formation.
The Belle II experiment is a new generation B-factory experiment at KEK in Japan aiming at the search for New Physics in a huge sample of B-meson decays. The commissioning of the accelerator and the ...detector for the first physics run has started from March this year. The Belle II High Level Trigger (HLT) is fully working in the beam run. The HLT is now operated with 1600 cores clusterized in 5 units, which is 1/4 of the full configuration. The software trigger is performed using the same o
ffl
ine reconstruction code, and events are classified into a set of physics categories. Only the events in the categories of interest are finally sent out to the storage. Live data quality monitoring is also performed on HLT. For the selected events, the reconstructed tracks are extrapolated to the surface of the pixel detector (PXD) and quickly fed back to the readout electronics for the real time data reduction by sending only the associated hits. The maximum trigger rate in the first physics run was 3.5kHz, and the Belle II data acquisition system was stably operated. There were several problems in the HLT operation, but they have successfully been fixed during the data taking period. The HLT reduction factor is measured to be 8 which is still higher than the design because of the high background environment.
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