Search

Several planetary formation models have been proposed to explain the observed abundance and variety of compositions of super-Earths and mini-Neptunes. In this context, multitransiting systems orbiting low-mass stars whose planets are close to the radius valley are benchmark systems, which help to elucidate which formation model dominates. We report the discovery, validation, and initial characterization of one such system, TOI-2096, composed of a super-Earth and a mini-Neptune hosted by a mid-type M dwarf located 48 pc away. We first characterized the host star by combining different methods. Then, we derived the planetary properties by modeling the photometric data from TESS and ground-based facilities. We used archival data, high-resolution imaging, and statistical validation to support our planetary interpretation. We found that TOI-2096 corresponds to a dwarf star of spectral type M4. It harbors a super-Earth (R$\sim1.2 R_{\oplus}$) and a mini-Neptune (R$\sim1.90 R_{\oplus}$) in likely slightly eccentric orbits with orbital periods of 3.12 d and 6.39 d, respectively. These orbital periods are close to the first-order 2:1 mean-motion resonance (MMR), which may lead to measurable transit timing variations (TTVs). We computed the expected TTVs amplitude for each planet and found that they might be measurable with high-precision photometry delivering mid-transit times with accuracies of $\lesssim$2 min. Moreover, measuring the planetary masses via radial velocities (RVs) is also possible. Lastly, we found that these planets are among the best in their class to conduct atmospheric studies using the James Webb Space Telescope (JWST). The properties of this system make it a suitable candidate for further studies, particularly for mass determination using RVs and/or TTVs, decreasing the scarcity of systems that can be used to test planetary formation models around low-mass stars., 25 pages, 21 figures. Aceptted for publication in Astronomy & Astrophysics

A hard X-ray engineering applications beamline (BL-02) was commissioned recently and started operation in March 2019 at the Indian synchrotron source, Indus-2. This bending-magnet-based beamline is capable of operating in various beam modes, viz. white, pink and monochromatic beam. The beamline utilizes the X-ray diffraction technique in energy-dispersive and angle-dispersive modes to carry out experiments mainly focused on engineering problems, viz. stress measurement, texture measurement and determination of elastic constants in a variety of bulk as well as thin-film samples. An open-cradle six-circle diffractometer with ∼12 kg load capacity allows accommodation of a wide variety of engineering samples and qualifies the beamline as a unique facility at Indus-2. The high-resolution mode of this beamline is suitably designed so as to carry out line profile analysis for characterization of micro- and nano-structures. In the present article the beamline is described starting from the beamline design, layout, optics involved, various operational modes and experimental stations. Experiments executed to validate the beamline design parameters and to demonstrate the capabilities of the beamline are also described. The future facilities to be incorporated to enhance the capabilities of the beamline are also discussed.

The new series oxadiazole derivatives were prepared by reacting aromatic carboxylic acids.In the present work 10 different 5-substituted-1,3,4-oxadiazole -2-amine derivatives (3a -i) were synthesized. Substituted carboxylic acid is converted into substituted ethyl benzoate by esterification. Different ethyl benzoate is converted into different aroyl hydrazide by treating with hydrazine hydrate.The different aroyl hydrazide is converted 5-substituted-1,3,4-oxadiazole-2-amine derivatives by treating with cyanogen bromide.Confirmation of the chemical structure of the synthesized compounds was substantiated by TLC,IR,1H NMR, and MS spectroscopy.In present study,a series of 1,3,4-oxadiazole derivatives(3a- i)were evaluated for in vivo anti-inflammatory activity by carrageenan induced paw edema method. The results of anti-inflammatory evaluation revealed that compounds 3c, 3e and3i exhibited significant anti-inflammatory activity at a dose of 25 mg kg-1 compared to indomethacin used as the reference standard.The anti-inflammatory activity investigation highlights that the synthesized compound 3e could be considered for further clinical studies.

In this paper, experimental study for shape control of silicon mirror is done by nonlinear piezoceramic actuator. A piezoelectric unimorph-based silicon mirror (PUSiM) is fabricated using APC 850 piezoceramic for shape control analysis. The piezo response function of all the actuators and profile of PUSiM are measured by confocal sensor at various applied electric fields to verify the nonlinearity of piezoceramic actuator. For comparison, electromechanical coupled finite element model of PUSiM is developed. Recently proposed iterative piezo response function-based optimization is used to calculate the electric field of piezoceramic actuators to achieve the target elliptical profile of PUSiM. At optimum voltage the achieved profile of PUSiM is quite close to the target elliptical profile with 193 nm root-mean-square error. Knowing the nonlinearity inherent in the piezoceramic actuators at high voltages the proposed measurement technique is a way forward for the shape control of structures and deformable mirrors.

Full list of authors: Luque, R.; Fulton, B. J.; Kunimoto, M.; Amado, P. J.; Gorrini, P.; Dreizler, S.; Hellier, C.; Henry, G. W.; Molaverdikhani, K.; Morello, G.; Pena-Monino, L.; Perez-Torres, M.; Pozuelos, F. J.; Shan, Y.; Anglada-Escude, G.; Bejar, V. J. S.; Bergond, G.; Boyle, A. W.; Caballero, J. A.; Charbonneau, D.; Ciardi, D. R.; Dufoer, S.; Espinoza, N.; Everett, M.; Fischer, D.; Hatzes, A. P.; Henning, Th; Hesse, K.; Howard, A. W.; Howell, S. B.; Isaacson, H.; Jeffers, S., V; Jenkins, J. M.; Kane, S. R.; Kemmer, J.; Khalafinejad, S.; Kidwell, R. C., Jr.; Kossakowski, D.; Latham, D. W.; Lillo-Box, J.; Lissauer, J. J.; Montes, D.; Orell-Miquel, J.; Palle, E.; Pollacco, D.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I; Ricker, G. R.; Rogers, L. A.; Sanz-Forcada, J.; Schlecker, M.; Schweitzer, A.; Seager, S.; Shporer, A.; Stassun, K. G.; Stock, S.; Tal-Or, L.; Ting, E. B.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; Villasenor, J.; Winn, J. N.; Winters, J. G.; Osorio, M. R. Zapatero.-- This is an Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., We report the discovery of a multiplanetary system transiting the M0 V dwarf HD 260655 (GJ 239, TOI-4599). The system consists of at least two transiting planets, namely HD 260655 b, with a period of 2.77 d, a radius of Rb = 1.240 ± 0.023 R⊕, a mass of Mb = 2.14 ± 0.34 M⊕, and a bulk density of ρb = 6.2 ± 1.0 g cm−3, and HD 260655 c, with a period of 5.71 d, a radius of , a mass of Mc = 3.09 ± 0.48 M⊕, and a bulk density of g cm−3. The planets have been detected in transit by the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed independently with archival and new precise radial velocities obtained with the HIRES and CARMENES instruments since 1998 and 2016, respectively. At a distance of 10 pc, HD 260655 has become the fourth closest known multitransiting planet system after HD 219134, LTT 1445 A, and AU Mic. Due to the apparent brightness of the host star (J = 6.7 mag), both planets are among the most suitable rocky worlds known today for atmospheric studies with the James Webb Space Telescope, both in transmission and emission. © R. Luque et al. 2022., This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. CARMENES is an instrument at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto (Almería, Spain), operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSlC). CARMENES was funded by the Max-Planck-Gesellschaft (MPG), the Consejo Superior de Investigaciones Científicas (CSIC), the Ministerio de Economía y Competitividad (MINECO) and the European Regional Development Fund (ERDF) through projects FICTS-2011-02, ICTS-2017-07-CAHA-4, and CAHA16-CE-3978, and the members of the CARMENES Consortium with additional contributions. Some of the observations in this paper made use of the NN-EXPLORE Exoplanet and Stellar Speckle Imager (NESSI). NESSI was funded by the NASA Exoplanet Exploration Program and the NASA Ames Research Center. NESSI was built at the Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. R.L. acknowledges funding from University of La Laguna through the Margarita Salas Fellowship from the Spanish Ministry of Universities ref. UNI/551/2021-May 26, and under the EU Next Generation funds. We acknowledge financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia e Innovación and the ERDF “A way of making Europe” through projects PID2019-109522GB-C5[1:4]/AEI/10.13039/501100011033 and the Centre of Excellence “Severo Ochoa” and “María de Maeztu” awards to the Instituto de Astrofísica de Canarias (CEX2019-000920-S), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737); the Generalitat de Catalunya/CERCA programme; the Deutsche Forschungsgemeinschaft (DFG) through the Major Research Instrumentation Programme and Research Unit FOR2544 “Blue Planets around Red Stars” (RE 2694/8-1, KU 3625/2-1), the Excellence Cluster ORIGINS (EXC-2094 – 390783311) and the Priority Programme “Exploring the Diversity of Extrasolar Planets” (JE 701/5-1); the National Aeronautics and Space Administration under grants 80NSSC21K0367 and 80NSSC22K0165 in support of Cycles 3 and 4 of the TESS Guest Investigator program; the National Science Foundation, Tennessee State University, and the State of Tennessee through its Centers of Excellence Program; and the Bulgarian BNSF program “VIHREN-2021” project No. KP-06-DV/5. The results reported herein benefited from collaborations and/or information exchange within the program “Alien Earths” (supported by the National Aeronautics and Space Administration under agreement No. 80NSSC21K0593) for NASA’s Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA’s Science Mission Directorate. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We thank VeraM. Passegger for a helpful discussion on the photospheric parameters of HD 260655.

Shape control of complex structures by optimizing the electrode potential is not achievable directly by analytical solutions and piezo response function base-optimization techniques due to the nonlinear response of piezoactuators. In the present work, a metaheuristic iterative piezo response function (iPRF)-based optimization technique is developed to achieve the arbitrary shape of piezoelectric unimorph (PU) using nonlinear piezoactuators. In this regard, a PU is fabricated using APC 850 piezoactuator to verify the nonlinear response in bending mode and nonlinear analytical model of PU. After verification, length of the inactive layer and number of piezoactuators in PU are modified to study the shape control. iPRF-based technique is used for the optimization of electric potential to achieve the target shape of modified piezoelectric unimorph (MPU) with various piezoactuators. The results of iPRF-based technique are compared with the results of simulated annealing (SA)-based direct optimization technique. Unlike SA-based direct optimization technique, prior knowledge of nonlinear coefficients of piezoactuator is not required in iPRF-based technique. Optimum values obtained from both the direct nonlinear solution- and iPRF-based optimization methods are same for all MPUs. Furthermore, the number of iterations of iPRF-based optimization approach is not affected by the number of piezoactuators used to achieve the desired shape.

Influence of thermal annealing on the ion beam sputtered FeCo(Nb)B quaternary alloy thin films having thickness ∼20 nm and 80 nm was investigated. Regardless of amorphous microstructure, the as-deposited films possess uniaxial magnetic anisotropy (UMA) in the film plane. Annealing at temperature ∼503 K results in amorphous to nanocrystalline phase transformation with precipitation of bcc-FeCo phase. With increasing annealing temperature, magnetic anisotropy gradually decreases and thermal annealing at 773 K results in complete disappearance of UMA. In-plane strain distribution in such nanocrystalline FeCo(Nb)B thin films was obtained by using laboratory and synchrotron X-ray diffraction (XRD) measurements. In-plane and out-of-plane X-ray diffraction measurements suggest, growth induced long range non-uniform tensile stress, as the possible origin of in-plane uniaxial magnetic anisotropy in such films. It is demonstrated that the stress distribution becomes uniform after annealing at 773 K and results in complete disappearance of magnetic anisotropy. The study further suggests that the presence of Nb in FeCoB film improves the thermal stability, inhibits grain growth and stabilizes bcc-FeCo phase up to elevated temperatures. This information is useful for magnetic tunnel junction application, where annealing of FeCoB magnetic electrode is essential.

In the present work, the energy dependent behaviour of half-lens polycapillaryoptics was investigated in detail using monochromatic synchrotron x-rays in the range of 8-20 keV. The x-rays were allowed to converge on the experimental station of BL-16 beamline. Using ahigh resolution x-ray CCD camera, we could determine spatial resolution of the focused x-ray beam at different energies. Spot size with distance was scanned for incident energy of 8 keV and minimum spot size of 48 µm was obtained. In addition, the variation of x-ray focal spot size as a function of incident energy was alsodetermined. The spot size was found to decrease linearly with increasing x-ray energy. It has been realized that the difference in structural tapering of the two polycapillary half-lensis primarily responsible for extremely tight or weak focusing of x-rays determining their focal distance and focal spot size.

A soft x-ray reflectivity beamline covering 100 eV – 1500 eV photon energy range is designed, fabricated and commissioned at bending magnet port of Indian synchrotron radiation facility Indus-2 to cater thin film/ multilayer users to analyze structural and optical behavior. The experimental station is designed to test x-ray mirrors upto ∼300 mm length in the soft x-ray region. The beamline provides monochromatic photons using a constant deviation angle variable line spacing plane grating monochromator with Hettrick type optics. Pre and post focusing toroidal mirrors are used to collect and deliver the beam from source to the experimental station. A reflectometer system comprising of a θ-2θ goniometer capable to hold big size samples upto 300 mm length and 5 kg weight is employed for performing various scans for reflectivity experiments. The goniometer is set in a vertical reflection geometry. The sample stage is electrically isolated from the rest of the system to enable one to record total electron yield signal for soft x-ray absorption measurements. This paper describes the beamline and its capabilities with examples of measured results.

著者人数: 68名(所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 鈴木, 大介), Accepted: 2018-02-06, 資料番号: SA1170273000

Pyroelectric detectors are widely used for infrared radiation detection, whereas these can also be used in the X-ray region. They have multiple advantages when used at synchrotron radiation sources, such as (a) can be used with a white beam (high flux), (b) have a flat spectral response, and (c) can be used both as a detector and as a sample. However, when used in the hard X-ray region, absorption in the detector plays an important role depending upon the thickness of the detector. Hence, the estimation of the responsivity of the detector is important. In this paper, we report an improved experimental setup for the measurement of a pyroelectric signal in the hard X-ray region. The responsivity (V/W) of a pyroelectric detector for absorbed radiation in the hard x-ray region is measured. Measurements of the K-edge x-ray absorption fine structure of 10-μm copper and nickel foils are carried out using a LiTaO3 pyroelectric detector and compared with the measurements carried out using an ionization chamber as a sensor for the same foils. Absorption spectra near the Ta LIII and LII edges in LiTaO3, measured using a LiTaO3 crystal both as a sample and as a sensor, are also reported in this paper.

A microfocus X-ray fluorescence spectroscopy beamline (BL-16) at the Indian synchrotron radiation facility Indus-2 has been constructed with an experimental emphasis on environmental, archaeological, biomedical and material science applications involving heavy metal speciation and their localization. The beamline offers a combination of different analytical probes, e.g. X-ray fluorescence mapping, X-ray microspectroscopy and total-external-reflection fluorescence characterization. The beamline is installed on a bending-magnet source with a working X-ray energy range of 4-20 keV, enabling it to excite K-edges of all elements from S to Nb and L-edges from Ag to U. The optics of the beamline comprises of a double-crystal monochromator with Si(111) symmetric and asymmetric crystals and a pair of Kirkpatrick-Baez focusing mirrors. This paper describes the performance of the beamline and its capabilities with examples of measured results.

We report the discovery of WASP-10b, a new transiting extrasolar planet (ESP) discovered by the WASP Consortium and confirmed using NOT FIES and SOPHIE radial velocity data. A 3.09 day period, 29 mmag transit depth, and 2.36 hour duration are derived for WASP-10b using WASP and high precision photometric observations. Simultaneous fitting to the photometric and radial velocity data using a Markov-chain Monte Carlo procedure leads to a planet radius of 1.28R_J, a mass of 2.96M_J and eccentricity of ~0.06. WASP-10b is one of the more massive transiting ESPs, and we compare its characteristics to the current sample of transiting ESP, where there is currently little information for masses greater than ~2M_J and non-zero eccentricities. WASP-10's host star, GSC 2752-00114 (USNO-B1.0 1214-0586164) is among the fainter stars in the WASP sample, with V=12.7 and a spectral type of K5. This result shows promise for future late-type dwarf star surveys., Comment: 6 Pages, 3 Figures, 3 Tables, accepted in MNRAS

The microlensing event OGLE-2008-BLG-510 is characterised by an evident asymmetric shape of the peak, promptly detected by the ARTEMiS system in real time. The skewness of the light curve appears to be compatible both with binary-lens and binary-source models, including the possibility that the lens system consists of an M dwarf orbited by a brown dwarf. The detection of this microlensing anomaly and our analysis demonstrates that: 1) automated real-time detection of weak microlensing anomalies with immediate feedback is feasible, efficient, and sensitive, 2) rather common weak features intrinsically come with ambiguities that are not easily resolved from photometric light curves, 3) a modelling approach that finds all features of parameter space rather than just the `favourite model' is required, and 4) the data quality is most crucial, where systematics can be confused with real features, in particular small higher-order effects such as orbital motion signatures. It moreover becomes apparent that events with weak signatures are a silver mine for statistical studies, although not easy to exploit. Clues about the apparent paucity of both brown-dwarf companions and binary-source microlensing events might hide here.

The degree of superlattice ordering (S), which may vary from zero (complete disorder) to one (fully ordered) is known to influence the magnetic and other physical properties of Fe-based nanocrystalline alloys. The direct correlation of S with physical properties of these alloys is not yet established. In the present work, we report on the correlation of the atomic order parameter (S) of bcc-FeCo phase, as calculated by anomalous diffraction measurements with the soft magnetic and mechanical properties of (Fe1-xCox)81Nb7B12 (x = 0.25, 0.33, 0.5, 0.66, 0.75) HITPERM alloys. The measured soft magnetic properties such as coercivity and saturation magnetization are found to have better correlation with the degree of atomic order than that of the crystalline volume fraction for the studied partially nanocrystalline alloys. Highest saturation magnetization (147 A.m2/kg) and lowest coercivity (18 A m−1) is recorded for the alloy (x = 0.66) with maximum degree of atomic order (S ~ 0.82). Ductility test shows better resistance against the embrittlement for the atomically ordered alloys as compared to disordered ones. Micro-hardness values are also high for atomically ordered alloys. The study suggests that apart from grain size, nanocrystalline fraction etc, the degree of atomic order is also an important structural parameter for tailoring the physical properties of such alloys for technological applications.

Analysis of chemical nature and electronic structure at the interface of a thin film medium is important in many technological applications as well as to understand overall efficiency of a thin film device. Synchrotron radiation based x-ray spectroscopy is a promising technique to study interface nature of the nanomaterials with atomic resolutions. A combined x-ray reflectivity and grazing incidence x-ray fluorescence measurement facility has been recently constructed at the BL-16 microfocus beamline of Indus-2 synchrotron facility to accomplish surface-interface microstructural characterization of thin layered materials. It is also possible to analyze contaminates or adsorbed ad-atoms on the surface of the thin nanostructure materials. The BL-16 beamline also provides an attractive platform to perform a variety of analytical research activities especially in the field of micro x-ray fluorescence and ultra-trace elements analysis using Synchrotron radiation. We describe various salient features of the BL-16 reflectometer experimental station and the detailed description of its capabilities through the measured results, obtained for various thin layered nanomaterials.

We have performed photometric observations of nearly 7 million stars with 8 < V < 15 with the SuperWASP-North instrument from La Palma between 2004 May-September. Fields in the RA range 17-18hr, yielding over 185,000 stars with sufficient quality data, have been searched for transits using a modified box least-squares (BLS) algorithm. We find a total of 58 initial transiting candidates which have high S/N in the BLS, show multiple transit-like dips and have passed visual inspection. Analysis of the blending and inferred planetary radii for these candidates leaves a total of 7 transiting planet candidates which pass all the tests plus 4 which pass the majority. We discuss the derived parameters for these candidates and their properties and comment on the implications for future transit searches., Comment: 17 pages, 24 figures, accepted by MNRAS

X-ray absorption near-edge spectra (XANES) of Ta-L2 and L3 edges in LiTaO3 (LTO) crystals are measured by measuring amplitude and phase of thermal waves generated within the LTO crystal, using pyroelectric property of LTO. Thus, LTO crystal is used both as a sample as well as sensor material. XANES of Ta-L edges in LTO are also measured by fluorescence. XANES spectra from fluorescence and first-principles simulations agree excellently well. The onset of the pre-edge region of XANES, measured by both techniques, extends below the edge by about 50 eV. This pre-edge onset of absorption is explained in terms of the core-hole lifetime effect on near-edge absorption using density functional theory. However, detailed nature of XANES peaks near Ta-L3 and Ta-L2 absorption edges, measured by thermal waves and fluorescence, differ. Possible origins of these differences are discussed.

We present a model of the stellar populations in the fields observed by one of the SuperWASP-N cameras in the 2004 observing season. We use the Besancon Galactic model to define the range of stellar types and metallicities present, and populate these objects with transiting extra-solar planets using the metallicity relation of Fischer & Valenti (2005). We investigate the ability of SuperWASP to detect these planets in the presence of realistic levels of correlated systematic noise (`red noise'). We find that the number of planets that transit with a signal-to-noise ratio of 10 or more increases linearly with the number of nights of observations. Based on a simulation of detection rates across 20 fields observed by one camera, we predict that a total of 18.6 \pm 8.0 planets should be detectable from the SuperWASP-N 2004 data alone. The best way to limit the impact of co-variant noise and increase the number of detectable planets is to boost the signal-to-noise ratio, by increasing the number of observed transits for each candidate transiting planet. This requires the observing baseline to be increased, by spending a second observing season monitoring the same fields., Omitted co-authors reinstated. 9 pages, 7 figures, accepted for publication in MNRAS

The SuperWASP project is an ultra-wide angle search for extra solar planetary transits. However, it can also serendipitously detect solar system objects, such as asteroids and comets. Each SuperWASP instrument consists of up to eight cameras, combined with high-quality peltier-cooled CCDs, which photometrically survey large numbers of stars in the magnitude range 7–15. Each camera covers a 7.8 × 7.8 degree field of view. Located on La Palma, the SuperWASP-I instrument has been observing the Northern Hemisphere with five cameras since its inauguration in April 2004.

The hard X-ray emission from the giant solar flare on 4 November 2003 (∼1947 UT) was observed by the hard X-ray/gamma ray spectrometer on the Ulysses spacecraft located at ∼114 degrees west of the Sun-Earth line at a distance of 5.28 All from the Sun A small hard X-ray burst during the early rise of the giant flare and a part of the decay of the hard X-ray emission associated with the giant flare were also observed by the hard X-ray imager an the RHESSI satellite located near the Earth. The maximum of the hard X-ray emission during the giant flare could not be observed by the RHESSI instrument because of satellite night. The flare view angles for Ulysses and RHESSI were ∼31° West and 83° East respectively. The H-α flare (importance 3B) was located at S19 W83 in the active region NOAA 10486. GOES observations of the associated soft X-ray emission saturated during the period 1943-1958 UT. It has been estimated that the soft X-ray maximum occurred at ∼1947 UT with peak flux equivalent to NOAA class ≥ X28. OVSA radio observations show that the flare produced intense microwave emission, the peak flux at 15.4 GHz being ∼60 000 sfu at - 1945 UT. Intense type II, III and IV radio hursts have also been reported at metric and decimetric wavelengths. RHESSI has provided 10-100 keV X-ray images and spectra for 1930-1936 UT (the early rise of the flare) and 10-30 keV images and spectra for 2016-2114 UT (a part of the late decay of the flare). Ulysses observed an increase in 25-150 keV X-rays from 1933 UT to 2015 UT with the maximum at ∼1944 UT, almost simultaneously with the maximum in 15.4 GHz radio emission and ∼3 min before the maximum in the soft X-ray emission. This indicates that the X-ray emission observed by Ulysses was mostly non-thermal. An assumed hard X-ray spectrum of ∼E 3.5 photons cm -2 s -1 keV -1 for >20 keV photons leads to an energy dissipation rate of ∼6.4 x 10 31 erg s -1 at the time of the hard X-ray maximum. The total energy in >20 keV electrons released during the flare is estimated to be ∼1.3 x 10 34 erg.

We obtain high-precision limb-darkening measurements in five bands (V, V_E, I_E, I, and H) for the K3 III (Teff=4200 K, [Fe/H]=+0.3, log(g)=2.3) source of the Galactic bulge microlensing event EROS BLG-2000-5. These measurements are inconsistent with the predictions of atmospheric models at >10 sigma. While the disagreement is present in all bands, it is most apparent in I, I_E and V_E, in part because the data are better and in part because the intrinsic disagreement is stronger. We find that when limb-darkening profiles are normalized to have unit total flux, the I-band models for a broad range of temperatures all cross each other at a common point. The solar profile also passes through this point. However, the profile as measured by microlensing does not. We conjecture that the models have incorporated some aspect of solar physics that is not shared by giant atmospheres., Submitted to ApJ, 28 pages including 8 figures

The hard X-ray/gamma-ray (HXR/GR) impulsive burst on 1991 June 30 (0255 UT) was associated with a flare which occured between 2 and 12 behind the east limb of the Sun. The partially occulted HXR/GR emission from this flare was detected at up to 100 MeV by three instruments on Earth-orbiting spacecraft: the Burst and Transient Source Experiment (BATSE) and the Energetic Gamma-Ray Experiment (EGRET) on CGRO and by the Payload for High Energy Burst Spectroscopy (PHEBUS) on GRANAT. As seen from the two spacecraft in Earth orbit, the size of the burst corresponds to that of a moderate electron-dominated GR event (Dingus et al. 1994; Vilmer et al. 1999). However, this event is one of the giant flares reported by Kane et al. (1995). It was observed by the Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) on Ulysses, located 135 east of the Earth-Sun line. GRB measured the total>28 keV HXR emission from the flare. In this paper we combine HXR observations by GRB and BATSE in order to determine the time evolution of the power-law index of the photon spectrum of the partially occulted HXR emission seen by BATSE and of the fraction R of the partially occulted to the total>28 keV emission. decreased from 5.4 to 2.6 and R varied from 20% at the beginning of the event down to

Hard X-ray and high frequency decimetric type III radio bursts have been observed in association with the soft X-raysolar flare (GOES class M 6.1) on 4 April 2002 (∼1532 UT). The flare apparently occurred ∼ 6 degrees behind the east limb of the Sun in the active region NOAA 9898. Hard X-ray spectra and images were obtained by the X-ray imager on RHESSI during the impulsive phase of the flare. The Brazilian Solar Spectroscope and Ondrejov Radio Telescopes recorded type III bursts in 800–1400 MHz range in association with the flare. The images of the 3–6, 6–12, 12–25, and 25–50 keV X-ray sources, obtained simultaneously by RHESSI during the early impulsive phase of the flare, show that all the four X-ray sources were essentially at the same location well above the limb of the Sun. During the early impulsive phase, the X-ray spectrum over 8–30 keV range was consistent with a power law with a negative exponent of ∼ 6. The radio spectra show drifting radio structures with emission in a relatively narrow (Δf ≤ 200 MHz) frequency range indicating injection of energetic electrons into a plasmoid which is slowly drifting upwards in the corona.

In flares that occur behind the limb, the intense chromospheric (foot-point) part of the hard X-ray source is occulted, thus permitting good observations of the coronal component. Between 15 and 18 April 2002, RHESSI observed a series of small (GOES Class C) flares produced by the active region NOAA 9905 as it rotated behind the west limb. A preliminary analysis of the observed hard X-ray sources in the 17–18 April 2002 flares has confirmed that flare-associated sources of gradual 12–25 keV X-ray emission can exist in the corona at heights up to 27000 km.

We present the analysis of MOA-2007-BLG-197Lb, the first brown dwarf companion to a Sun-like star detected through gravitational microlensing. The event was alerted and followed-up photometrically by a network of telescopes from the PLANET, MOA, and uFUN collaborations, and observed at high angular resolution using the NaCo instrument at the VLT. From the modelling of the microlensing light curve, we derived the binary lens separation in Einstein radius units (s~1.13) and a mass ratio of (4.732+/-0.020)x10^{-2}. Annual parallax, lens orbital motion and finite source effects were included in the models. To recover the lens system's physical parameters, we combined the resulting light curve best-fit parameters with (J,H,Ks) magnitudes obtained with VLT NaCo and calibrated using IRSF and 2MASS data. We derived a lens total mass of 0.86+/-0.04 Msun and a lens distance of 4.2+/-0.3 kpc. We find that the companion of MOA-2007-BLG-197L is a brown dwarf of 41+/-2 Mjup observed at a projected separation of 4.3+/-0.1 AU, and orbits a 0.82+/-0.04 Msun G-K dwarf star. We study the statistical properties of this population of brown dwarfs detected by microlensing, transit, radial velocity, and direct imaging (most of these objects orbit solar-type stars), and we performed a two-dimensional, non-parametric probability density distribution fit to the data, which draws a structured brown dwarf landscape. We confirm the existence of a region that is strongly depleted in objects at short periods and intermediate masses (P500 d) and high masses (M>50 Mjup). While these data provide important clues on mechanisms of brown dwarfs formation, more data are needed to establish their relative importance, in particular as a function of host star mass., 16 pages, 12 figures

We analyze five years of PLANET photometry of microlensing events toward the Galactic bulge to search for the short-duration deviations from single lens light curves that are indicative of the presence of planetary companions to the primary microlenses. Using strict event selection criteria, we construct a well defined sample of 43 intensively monitored events. We search for planetary perturbations in these events over a densely sampled region of parameter space spanning two decades in mass ratio and projected separation, but find no viable planetary candidates. By combining the detection efficiencies of the events, we find that, at 95% confidence, less than 25% of our primary lenses have companions with mass ratio q=0.01 and separations in the lensing zone, 0.6-1.6 Einstein ring radii. Using a model of the mass, velocity and spatial distribution of bulge lenses, we infer that the majority of our lenses are likely M dwarfs in the Galactic bulge. We conclude that less than 33% of M-dwarfs in the Galactic bulge have Jupiter-mass companions between 1.5 and 4 AU, and less than 45% have 3 Jupiter-mass companions between 1 and 7 AU, the first significant limits on planetary companions to M-dwarfs. We consider the effects of the finite size of the source stars and changing our detection criterion, but find that these do not alter our conclusions substantially.

Preliminary results of the association between type III decimetric bursts, mainly having center frequency above 1000 MHz and recorded by Phoenix radio spectrometer, and seven hard X-ray flares observed by the Yohkoh/HXT from September, 1992 to October, 1993 are reported here. (a) For an assumed improved density model of the solar chromosphere, an average electron beam velocity (∼ 0.16 c) and hence an average electron energy (∼ 7 keV) was inferred from the average frequency drift rate (∼ 1350 MHz/s) of 160 isolated type III bursts. Assuming the electrons lose energy primarily by collisions, the height of injection of the energetic electrons was estimated (1.2 × 109 – 4.5 × 109 cm). (b) In two flares at the onset of the bursts, the correlation between X-rays and radio was better at lower frequencies (≤ 500 MHz). However, during the time evolution of those flares, the correlation improved for higher and higher frequencies (≥ 800 MHz), suggesting that the acceleration region was displaced towards the photosphere. The estimated velocity of the acceleration region is ∼ 3 × 103 – 8 × 103 km/s. (c) In two flares, the enhancement of the radio decimetric emission above 500 MHz started earlier (∼ 10 s) than the X-ray emissions, suggesting in case of these two flares that the acceleration region is located near to where the decimetric emission is generated.

We review the current status and future prospects of the PLANET collaboration, an international team of astronomers performing high-precision photometric monitoring of microlensing events. Our photometric precision and sampling is characterised and the suitability of the database for variable star studies is discussed. Preliminary results on K-giant stability are presented.

The Solar X-Ray/Cosmic Gamma-Ray Burst Experiment aboard the interplanetary spacecraft Ulysses has provided extensive observations of solar hard X-ray flares from a variety of angles with respect to the Sun-Earth line. During the period 1991 October-1993 June, Ulysses observed 13 flares that were also observed by the X-ray instruments aboard the Japanese satellite Yohkoh located near Earth. At least 12 flares were in full view of both the spacecraft. Eight flares, for which hard X-ray spectra were available, are examined to determine the directivity of the 20-125 keV hard X-ray sources in solar flares. They include one flare for which the view angles of Ulysses and Yohkoh were 80° and 25°, respectively. No evidence of systematic directivity was found within the uncertainty (a factor of ~2) of these measurements. These and other observations of directivity at higher energies are consistent with a nearly isotropic distribution of energetic electrons in most solar flares.

An Energy Scanning X-ray Absorption Fine Structure spectroscopy beamline has recently been installed and commissioned at BL-09 bending magnet port of INDUS-2 synchrotron source, Indore. The beamline uses an UHV compatible fixed exit double crystal monochromator (DCM) with two Si (111) crystals. Two grazing incidence cylindrical mirrors are also used in this beamline; the pre-mirror is used as a collimating mirror while the post mirror is used for vertical focusing and higher harmonic rejection. In this beamline it is possible to carry out EXAFS measurements both in transmission and fluorescence mode on various types of samples, using Ionization chamber detectors and solid state drift detector respectively. In this paper, results from first experiments of the Energy Scanning EXAFS beamline are presented.

A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals., 5 pages, 4 figures and ApJ submitted

Gravitational microlensing events produced by lenses composed of binary masses are important because they provide a major channel to determine physical parameters of lenses. In this work, we analyze the light curves of two binary-lens events OGLE-2006-BLG-277 and OGLE-2012-BLG-0031 for which the light curves exhibit strong deviations from standard models. From modeling considering various second-order effects, we find that the deviations are mostly explained by the effect of the lens orbital motion. We also find that lens parallax effects can mimic orbital effects to some extent. This implies that modeling light curves of binary-lens events not considering orbital effects can result in lens parallaxes that are substantially different from actual values and thus wrong determinations of physical lens parameters. This demonstrates the importance of routine consideration of orbital effects in interpreting light curves of binary-lens events. It is found that the lens of OGLE-2006-BLG-277 is a binary composed of a low-mass star and a brown dwarf companion., 6 pages and 4 figures

We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010-03-18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source lightcurve, we demonstrate that it is an irregular variable over time scales >200d. Its dereddened color, $(V-I)_{S,0}$, is 1.221$\pm$0.051mag and from our lens model we derive a source radius of 14.7$\pm$1.3 $R_{\odot}$, suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q=0.0654$\pm$0.0006. The Einstein crossing time of the event, $T_{\rm{E}}=44.3$\pm$0.1d, was sufficiently long that the lightcurve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, $D_L$=2.8$\pm$0.4kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with $M_{L,p}$=0.16$\pm0.03M_{\odot}$ while the companion has $M_{L,s}$=11.0$\pm2.0M_{\rm{J}}$ putting it in the boundary zone between planets and brown dwarfs., 24 pages, 8 figures, best viewed in colour, accepted by ApJ

Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted.Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit.Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components.Results. We find that the source star is a giant G star with radius 9 R⊙. The grid search gives two local minima, which correspond to the theoretical degeneracy s ≡ s-1. We find that the lens is composed of a brown dwarf secondary of mass MS = 0.05 M⊙ orbiting a primary M-star of mass MP = 0.18 M⊙. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries.Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf. Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted. Aims. MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit. Methods. Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components. Results. We find that the source star is a giant G star with radius 9 R . The grid search gives two local minima, which correspond to the theoretical degeneracy s s . We find that the lens is composed of a brown dwarf secondary of mass M = 0.05 M orbiting a primary M-star of mass M = 0.18 M . We also reveal a new mass-ratio degeneracy for the central caustics of close binaries. Conclusions. As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

We report commissioning of the microprobe-XRF beamline on Indus-2 synchrotron source. The beamline has been recently made operational and is now open for the user's experiments. The beamline comprises of Si(111) double crystal monochromator and Kirkpatrick-Baez focusing optics. The beamline covers wide photon energy range of 4 – 20 keV using both collimated and micro-focused beam modes. The design details and the first commissioning results obtained using this beamline are presented.

Gradual hard X-ray/radio bursts are characterized by their long duration, smooth time profile, time delays between peaks at different hard X-ray energies and microwaves, and radiation from extended sources in the low and middle corona. Their characteristic properties have been ascribed to the dynamic evolution of the accelerated electrons in coronal magnetic traps or to the separate acceleration of high-energy electrons in a 'second step' process. The information available so far was drawn from quality considerations of time profiles or even only from the common occurrence of emissions in different spectral ranges. This paper presents model computations of the temporal evolution of hard X-ray and microwave spectra, together with a qualitative discussion of radio lightcurves over a wide spectral range, and metric imaging observations. The basis hypothesis investigated is that the peculiar 'gradual' features can be related to the dynamical evolution of electrons injected over an extended time interval in a coronal trap, with electrons up to relativistic energies being injected simultaneously. The analyzed event (26 April. 1981) is particularly challenging to this hypothesis because of the long time delays between peaks at different X-ray energies and microwave frequencies. The observations are shown to be consistent with the hypothesis, provided that the electrons lose their energy by Coulomb collisions and possibly betatron deceleration. The access of the electrons to different coronal structures varies in the course of the event. The evolution and likely destabilization of part of the coronal plasma-magnetic field configuration is of crucial influence in determining the access to these structures and possibly the dynamical evolution of the trapped electrons through betatron deceleration in the late phase of the event.

We present the first example of binary microlensing for which the parameter measurements can be verified (or contradicted) by future Doppler observations. This test is made possible by a confluence of two relatively unusual circumstances. First, the binary lens is bright enough (I=15.6) to permit Doppler measurements. Second, we measure not only the usual 7 binary-lens parameters, but also the 'microlens parallax' (which yields the binary mass) and two components of the instantaneous orbital velocity. Thus we measure, effectively, 6 'Kepler+1' parameters (two instantaneous positions, two instantaneous velocities, the binary total mass, and the mass ratio). Since Doppler observations of the brighter binary component determine 5 Kepler parameters (period, velocity amplitude, eccentricity, phase, and position of periapsis), while the same spectroscopy yields the mass of the primary, the combined Doppler + microlensing observations would be overconstrained by 6 + (5 + 1) - (7 + 1) = 4 degrees of freedom. This makes possible an extremely strong test of the microlensing solution. We also introduce a uniform microlensing notation for single and binary lenses, we define conventions, summarize all known microlensing degeneracies and extend a set of parameters to describe full Keplerian motion of the binary lenses., Comment: 51 pages, 8 figures, 2 appendices. Submitted to ApJ. Fortran codes for Appendix B are attached to this astro-ph submission and are also available at http://www.astronomy.ohio-state.edu/~jskowron/OGLE-2009-BLG-020/

We present the analysis result of a gravitational binary-lensing event OGLE-2005-BLG-018. The light curve of the event is characterized by 2 adjacent strong features and a single weak feature separated from the strong features. The light curve exhibits noticeable deviations from the best-fit model based on standard binary parameters. To explain the deviation, we test models including various higher-order effects of the motions of the observer, source, and lens. From this, we find that it is necessary to account for the orbital motion of the lens in describing the light curve. From modeling of the light curve considering the parallax effect and Keplerian orbital motion, we are able to measure not only the physical parameters but also a complete orbital solution of the lens system. It is found that the event was produced by a binary lens located in the Galactic bulge with a distance $6.7\pm 0.3$ kpc from the Earth. The individual lens components with masses $0.9\pm 0.3\ M_\odot$ and $0.5\pm 0.1\ M_\odot$ are separated with a semi-major axis of $a=2.5 \pm 1.0$ AU and orbiting each other with a period $P=3.1 \pm 1.3$ yr. The event demonstrates that it is possible to extract detailed information about binary lens systems from well-resolved lensing light curves., 19 pages, 6 figures

Transiting exoplanets provide access to data to study the mass-radius relation and internal structure of extrasolar planets. Long-period transiting planets allow insight into planetary environments similar to the Solar System where, in contrast to hot Jupiters, planets are not constantly exposed to the intense radiation of their parent stars. Observations of secondary eclipses additionally permit studies of exoplanet temperatures and large-scale exo-atmospheric properties. We show how transit and eclipse probabilities are related to planet-star system geometries, particularly for long-period, eccentric orbits. The resulting target selection and observational strategies represent the principal ingredients of our photometric survey of known radial-velocity planets with the aim of detecting transit signatures (TERMS)., Comment: 3 pages, 2 figures. Comments: To appear in the ASP Conference Proceedings: Detection and Dynamics of Transiting Exoplanets; Proceedings of Haute Provence Observatory Colloquium (23-27 August 2010); Edited by F. Bouchy, R. F. Diaz, and C. Moutou

An Angle dispersive x‐ray diffraction (ADXRD) beamline on bending magnet source of Indus‐2 synchrotron (2.5 GeV, 300 mA) has been commissioned, for the study of single and polycrystalline samples. The beamline optics is based on vertically focusing Pt‐coated pre and post mirrors and sagittal focusing Si (311) based double crystal monochromator. Experimental station consists of a six circle diffractometer equipped with scintillation detector and an image plate area detector for powder diffraction. XRD experiments have been performed to study single crystal and polycrystalline samples.