scholarly journals Preliminary Results on Irradiance Measurements from Lyra and Swap

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
S. T. Kumara ◽  
R. Kariyappa ◽  
M. Dominique ◽  
D. Berghmans ◽  
L. Damé ◽  
...  
Keyword(s):  
High Temporal Resolution ◽  
Preliminary Results ◽  
Spatially Resolved ◽  
Large Yield ◽  
Active Pixel ◽  
Integrated Intensity ◽  
Actual Contribution ◽  
The Individual ◽  
Aluminum Filter ◽  
Full Disk

The first and preliminary results of the photometry of Large Yield Radiometer (LYRA) and Sun Watcher using Active Pixel system detector and Image Processing (SWAP) onboard PROBA2 are presented in this paper. To study the day-to-day variations of LYRA irradiance, we have compared the LYRA irradiance values (observed Sun as a star) measured in Aluminum filter channel (171 Å–500 Å) with spatially resolved full-disk integrated intensity values measured with SWAP (174 Å) and Ca II K 1 Å index values (ground-based observations from NSO/Sac Peak) for the period from 01 April 2010 to 15 Mar 2011. We found that there is a good correlation between these parameters. This indicates that the spatial resolution of SWAP complements the high temporal resolution of LYRA. Hence SWAP can be considered as an additional radiometric channel. Also the K emission index is the integrated intensity (or flux) over a 1 Å band centered on the K line and is proportional to the total emission from the chromosphere; this comparison clearly explains that the LYRA irradiance variations are due to the various magnetic features, which are contributing significantly. In addition to this we have made an attempt to segregate coronal features from full-disk SWAP images. This will help to understand and determine the actual contribution of the individual coronal feature to LYRA irradiance variations.

scholarly journals Constraining the stellar energetic particle flux in young solar-like stars

2018 ◽  
Vol 14 (S345) ◽  
pp. 310-311
Author(s):  
Ch. Rab ◽  
M. Padovani ◽  
M. Güdel ◽  
I. Kamp ◽  
W-F. Thi ◽  
...  
Keyword(s):  
Particle Flux ◽  
High Energy ◽  
Young Stars ◽  
Solar Cosmic Rays ◽  
Spatially Resolved ◽  
T Tauri ◽  
Ionization Sources ◽  
Hydrogen Ionization ◽  
The Individual ◽  
The Impact

AbstractAnomalies in the abundance measurements of short lived radionuclides in meteorites indicate that the protosolar nebulae was irradiated by a large number of energetic particles (E≳ 10 MeV), often called solar cosmic rays. The particle flux of the contemporary Sun cannot explain these anomalies, but, similar to T Tauri stars, the young Sun was more active and probably produced enough high energy particles. However, the stellar particle (SP) flux of young stars is essentially unknown. We model the impact of high-energy ionization sources on the chemistry of the circumstellar environment (disks and envelopes). The model includes X-ray radiative transfer and makes use of particle transport models to calculate the individual molecular hydrogen ionization rates. We study the impact on the chemistry via the ionization tracers HCO+ and N2H+. We argue that spatially resolved observations of those molecules combined with detailed models allow for disentangling the contribution of the individual high-energy ionization sources and to put constraints on the SP flux in young stars.

scholarly journals Quantifying changes and trends in glacier area and volume in the Austrian Ötztal Alps (1969-1997-2006)

2009 ◽  
Vol 3 (2) ◽  
pp. 205-215 ◽  
Author(s):  
J. Abermann ◽  
A. Lambrecht ◽  
A. Fischer ◽  
M. Kuhn
Keyword(s):  
Length Change ◽  
High Temporal Resolution ◽  
Glacier Area ◽  
Thickness Change ◽  
Additional Information ◽  
Digital Elevation ◽  
Glacier Changes ◽  
The Individual ◽  
Individual Size ◽  
Area And Volume

Abstract. In this study we apply a simple and reliable method to derive recent changes in glacier area and volume by taking advantage of high resolution LIDAR (light detection and ranging) DEMs (digital elevation models) from the year 2006. Together with two existing glacier inventories (1969 and 1997) the new dataset enables us to quantify area and volume changes over the past 37 years at three dates. This has been done for 81 glaciers (116 km2) in the Ötztal Alps which accounts for almost one third of Austria's glacier extent. Glacier area and volume have reduced drastically with significant differences within the individual size classes. Between 1997 and 2006 an overall area loss of 10.5 km2 or 8.2% occurred. Volume has reduced by 1.0 km3 which accounts for a mean thickness change of −8.2 m. The availability of three comparable inventories allows a comprehensive size and altitude dependent analysis of glacier changes but lacks a high temporal resolution. For the comparison of rates of changes between the two different periods (1969 to 1997 with 1997 to 2006) we propose two approaches in this study: a) to estimate mean overall rates of changes (including a period of advance) and b) to extract periods of net-retreat by using additional information (length change and mass balance measurements). Analysis of the resulting acceleration factors reveals that the retreat of volume and mean thickness changes has accelerated significantly more than that of area changes.

scholarly journals Full-Disk Observations of Solar Oscillations from the Geographic South Pole: Latest Results

1983 ◽  
Vol 66 ◽  
pp. 55-66
Author(s):  
Gérard Grec ◽  
Eric Fossat ◽  
Martin A. Pomerantz
Keyword(s):  
Amplitude Modulation ◽  
Doppler Shift ◽  
Normal Modes ◽  
South Pole ◽  
Solar Oscillations ◽  
The Individual ◽  
Full Disk

AbstractThis paper presents the latest results obtained from the analysis of the full-disk Doppler shift observations obtained at the geographic South Pole in 1981. About 80 normal modes of oscillation (l = 0–3) have now been identified. Their frequencies range from 1886 μHz (l = 1, n = 12) to 5074.5 μHz (l = 2, n = 35), and their amplitudes are as low as 2.5 cm s–1. Amplitude modulation occurs with periods of 1–2 days, and the individual oscillations appear to be excited randomly and independently. In cases where other groups have observed some of the modes identified by us, the agreement in frequency is good.

scholarly journals The MALATANG survey: dense gas and star formation from high-transition HCN and HCO+ maps of NGC 253

2020 ◽  
Vol 494 (1) ◽  
pp. 1276-1296
Author(s):  
Xue-Jian Jiang ◽  
Thomas R Greve ◽  
Yu Gao ◽  
Zhi-Yu Zhang ◽  
Qinghua Tan ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Average Density ◽  
Dense Gas ◽  
James Clerk Maxwell ◽  
Physical Conditions ◽  
Spatially Resolved ◽  
Stellar Component ◽  
Integrated Intensity ◽  
High Transition

ABSTRACT To study the high-transition dense-gas tracers and their relationships to the star formation of the inner ∼2 kpc circumnuclear region of NGC 253, we present HCN J = 4−3 and HCO+ J = 4−3 maps obtained with the James Clerk Maxwell Telescope. Using the spatially resolved data, we compute the concentration indices r90/r50 for the different tracers. HCN and HCO+ 4–3 emission features tend to be centrally concentrated, which is in contrast to the shallower distribution of CO 1–0 and the stellar component. The dense-gas fraction (fdense, traced by the velocity-integrated-intensity ratios of HCN/CO and HCO+/CO) and the ratio R31 (CO 3–2/1–0) decline towards larger galactocentric distances, but increase with higher star formation rate surface density. The radial variation and the large scatter of fdense and R31 imply distinct physical conditions in different regions of the galactic disc. The relationships of fdense versus Σstellar, and SFEdense versus Σstellar are explored. SFEdense increases with higher Σstellar in this galaxy, which is inconsistent with previous work that used HCN 1–0 data. This implies that existing stellar components might have different effects on the high-J HCN and HCO+ than their low-J emission. We also find that SFEdense seems to be decreasing with higher fdense which is consistent with previous works, and it suggests that the ability of the dense gas to form stars diminishes when the average density of the gas increases. This is expected in a scenario where only the regions with high-density contrast collapse and form stars.

scholarly journals Observations on the increase in size at moulting in the lobster (Homarus vulgaris M.-Edw.)

1958 ◽  
Vol 37 (3) ◽  
pp. 603-606 ◽  
Author(s):  
H. J. Thomas
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Increment ◽  
American Lobster ◽  
Limited Data ◽  
Preliminary Results ◽  
Home Department ◽  
The Individual ◽  
Marine Laboratory

A knowledge of growth rates is a pre-requisite in estimating the effect of fishing upon the available stocks. In Crustacea, where there is no known means of establishing accurately the age of the individual, the importance of measuring the growth rate is increased whilst its determination is made more difficult. In Homarus vulgaris some experiments were undertaken by Dannevig (1936), and Wilder (1953) gives considerable data for the American lobster. Results suggest that the growth increment is not uniform in all latitudes. Experiments to augment the limited data available for H. vulgaris and to establish the increase in size at moulting in local lobster stocks were therefore undertaken by the Marine Laboratory of the Scottish Home Department at Aberdeen. A statement of some preliminary results was given in Report on the Fisheries of Scotland (Lucas, 1957, p. 58).

Amplitude and Direction of Saccadic Eye Movements Depend on the Synchronicity of Collicular Population Activity

2004 ◽  
Vol 92 (1) ◽  
pp. 424-432 ◽  
Author(s):  
Michael Brecht ◽  
Wolf Singer ◽  
Andreas K. Engel
Keyword(s):  
Eye Movements ◽  
Saccadic Eye Movements ◽  
Brain Structures ◽  
High Temporal Resolution ◽  
Temporal Relations ◽  
Neuronal Responses ◽  
Population Activity ◽  
Neuronal Processing ◽  
The Individual ◽  
Cat Superior Colliculus

Synchronization of neuronal discharges has been observed in numerous brain structures, but opinions diverge regarding its significance in neuronal processing. Here we investigate whether the motion vectors of saccadic eye movements evoked by electrical multisite stimulation of the cat superior colliculus (SC) are influenced by varying the degree of synchrony between the stimulus trains. With synchronous activation of SC sites, the vectors of the resulting saccades correspond approximately to the averages of the vectors of saccades evoked from each site alone. In contrast, when the pulses of trains applied to the different sites are temporally offset by as little as 5–10 ms, the vectors of the resulting saccades come close to the sum of the individual vectors. Thus saccade vectors depend not only on the site and amplitude of collicular activation but also on the precise temporal relations among the respective spike trains. These data indicate that networks within or downstream from the SC discriminate with high temporal resolution between synchronous and asynchronous population responses. This supports the hypothesis that information is encoded not only in the rate of neuronal responses but also in the precise temporal relations between discharges.

scholarly journals Properties of ionized outflows in MaNGA DR2 galaxies

2019 ◽  
Vol 486 (1) ◽  
pp. 344-359 ◽  
Author(s):  
Bruno Rodríguez del Pino ◽  
Santiago Arribas ◽  
Javier Piqueras López ◽  
Montserrat Villar-Martín ◽  
Luis Colina
Keyword(s):  
Star Formation ◽  
Emission Region ◽  
Ionization Mechanism ◽  
Host Galaxies ◽  
Star Forming ◽  
Spatially Resolved ◽  
Nearby Galaxies ◽  
Nuclear Regions ◽  
The Individual ◽  
Stellar Masses

ABSTRACT We present the results from a systematic search and characterization of ionized outflows in nearby galaxies using the data from the second Data Release of the Mapping Nearby Galaxies at Arecibo Point Observatory (MaNGA) Survey (DR2; >2700 galaxies, z ≤ 0.015). Using the spatially resolved spectral information provided by the MANGA data, we have identified ∼5200 H α-emitting regions across the galaxies and searched for signatures of ionized outflows. We find evidence for ionized outflows in 105 regions from 103 galaxies, roughly 7 per cent of all the H α-emitting galaxies identified in this work. Most of the outflows are nuclear, with only two cases detected in off-nuclear regions. Our analysis allows us to study ionized outflows in individual regions with star formation rates (SFRs) down to ∼0.01 M⊙ yr−1, extending the ranges probed by previous works. The kinematics of the outflowing gas is strongly linked to the type of ionization mechanism: regions characterized by low-ionization emission region emission (LIER) host the outflows with more extreme kinematics (FWHMbroad ∼ 900 km s−1), followed by those originated in active galactic nuclei (550 km s−1), ‘Intermediate’ (450 km s−1), and star-forming (350 km s−1) regions. Moreover, in most of the outflows we find evidence for gas ionized by shocks. We find a trend for higher outflow kinematics towards larger stellar masses of the host galaxies but no significant variation as a function of star formation properties within the SFR regime we probe (∼0.01–10 M⊙ yr−1). Our results also show that the fraction of outflowing gas that can escape from galaxies decreases towards higher dynamical masses, contributing to the preservation of the mass–metallicity relation by regulating the amount of metals in galaxies. Finally, assuming that the extensions of the outflows are significantly larger than the individual star-forming regions, as found in previous works, our results also support the presence of star formation within ionized outflows, as recently reported by Maiolino et al. (2017) and Gallagher et al. (2018).

scholarly journals Interactional synchrony: signals, mechanisms and benefits

2020 ◽  
Author(s):  
Stefanie Hoehl ◽  
Merle Fairhurst ◽  
Annett Schirmer
Keyword(s):  
Temporal Cortex ◽  
Group Living ◽  
High Temporal Resolution ◽  
Emotional Information ◽  
Interactional Synchrony ◽  
Individual Level ◽  
Temporal Regularity ◽  
Superior Temporal Cortex ◽  
Interval Sequence ◽  
The Individual

Abstract Many group-living animals, humans included, occasionally synchronize their behavior with that of conspecifics. Social psychology and neuroscience have attempted to explain this phenomenon. Here we sought to integrate results around three themes: the stimuli, the mechanisms and the benefits of interactional synchrony. As regards stimuli, we asked what characteristics, apart from temporal regularity, prompt synchronization and found that stimulus modality and complexity are important. The high temporal resolution of the auditory system and the relevance of socio-emotional information endow auditory, multimodal, emotional and somewhat variable and adaptive sequences with particular synchronizing power. Looking at the mechanisms revealed that traditional perspectives emphasizing beat-based representations of others’ signals conflict with more recent work investigating the perception of temporal regularity. Timing processes supported by striato-cortical loops represent any kind of repetitive interval sequence fairly automatically. Additionally, socio-emotional processes supported by posterior superior temporal cortex help endow such sequences with value motivating the extent of synchronizing. Synchronizing benefits arise from an increased predictability of incoming signals and include many positive outcomes ranging from basic information processing at the individual level to the bonding of dyads and larger groups.

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