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Astrophysics and Astrononmy
Continuum emission enhancements in flares observed by ROSA and IRIS
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
19.06.2018
Co-author:
V. Capparelli, M. Mathioudakis, P. Keys, L. Fletcher, S. Criscuoli, M. Falco, S.L. Guglielmino, and M. Murabito
Abstract:
During solar flares, magnetic energy can be converted into electromagnetic radiation from radio waves to gamma rays. In the most energetic events, enhancements in the continuum at visible wavelengths may be present (white-light [WL] flares). Recently, the WL emission has also been correlated with enhancements in the FUV and NUV passbands. In this context, we describe observations acquired by ground-based (ROSA@DST) and satellite (IRIS) instruments during two consecutive C7.0 and X1.6 flares occurred in active region NOAA 12205 on 2014 November 7.
The results of the analysis of these data show the presence of continuum enhancements during the evolution of the events, observed both in ROSA images and in IRIS spectra. Moreover, we analyze the role played by the evolution of the δ sunspots of the active region in the flare triggering, discussing the disappearance of a large portion of penumbra around these sunspots as a further consequence of these energetic flares. We expect that high-resolution observations acquired during the EST operations will enable us to extend our knowledge about the physical process that determines WL emission during solar events like those discussed here.
Comparison of different populations of granular features in the solar photosphere
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
22.06.2018
Co-author:
G. Puglisi, S.L. Guglielmino, P. Romano, I. Ermolli, and F. Zuccarello
Abstract:
One of the most visible manifestations of convective motions occurring in
the uppermost layers of the solar convection zone is the granulation. Strong
magnetic fields hinder the convective motions, but the appearance of bright
structures such as umbral dots (UDs) and light bridges (LBs) in sunspots also
shows that in strong magnetic field regions, the convection is not completely
suppressed. To improve the current knowledge of the mechanism behind
the appearance of the different bright structures in sunspots, we investigate
the properties of the granules identified by a new segmentation algorithm in
regions characterized by different magnetic field strength.
We analyzed data relevant to a large sunspot with a LB observed in AR
NOAA 11263. The data were acquired by the CRisp Imaging SpectroPo-
larimeter at the SST on 6 August 2011. We applied a new segmentation
algorithm to the data acquired along the Fe I 630.15 nm line.
We found that the granules in the LB have a diameter between 0
.
22
′′
and 0
.
99
′′
, being smaller than the granules in a nearby plage region (PL)
and similar to those of the UDs. The values of the mean continuum inten-
sity, between 0.42 Ic and 0.98 Ic for the LB granules, are similar to those
of the UDs. PL granules have higher values of continuum intensity, proba-
bly reflecting different conditions of the plasma convection. Mean Doppler
velocity and mean magnetic field strength have similar values between LB
granules and UDs as well.
Different values for the physical properties analyzed have been found
between the granules of the PL and LB granules of the three analyzed so-
lar regions, suggesting that PL and sunspot granules have different physical
properties. This clearly depends on the different physical conditions of the
regions where these two types of granular structures are embedded and con-
firms the recent findings on the similarity between granules in PL and quiet
Sun regions. Finally, a noteworthy result is that the granules observed in
the faint LB have physical properties similar to those found for UDs.
Observation of magnetic reconnection around a 3D null point
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
18.06.2018
Co-author:
Salvo Luigi Guglielmino, Mariachiara Falco, Mariarita Murabito
Abstract:
We describe high-resolution observations of a GOES B-class flare observed at the Dunn Solar Telescope with IBIS and ROSA instruments. The flare was characterized by a circular ribbon at chromospheric level and was interpreted as a consequence of a magnetic reconnection event that occurred at a three-dimensional (3D) coronal null point located above a supergranular cell. We highlight some interesting observational aspects that need to be explained by models. We observe a bundle of loops corresponding to the outer spine that becomes brighter a few minutes before the onset of the flare. The circular ribbon was formed by several adjacent compact kernels with a size of 1″–2″ and brightening sequentially in clockwise direction. We note that the kernels with a stronger intensity emission were located at the outer footpoint of the darker filaments, departing radially from the center of the supergranular cell. The site of the 3D null point and the shape of the outer spine were also detected by RHESSI in the low-energy channel between 6.0 and 12.0 keV. We ascribe the low intensity of the flare to the low amount of the involved magnetic flux and to its symmetric magnetic configuration.
The Broad Band Imager for EST
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
14.06.2018
Co-author:
Scuderi S., Cecconi M.
Abstract:
The BBI (Broad Band Imager) for EST will be one of the 'first light' instruments of the telescope. The scientific objectives will be the the study of fundamental astrophysical processes at their intrinsic scales in the Sun's atmosphere, and this goal will be reached with an instrument able to obtain diffraction limited images over the full field of view of EST at multiple wavelengths and high frame rate. The BBI will cover the 390 to 900nm wavelength range, using two different arms(390-500nm and 600-900nm), and three different channels. Each subchannel will be further split in thre subchannels, each one served by a different 4kx4k detector; one subchannel will be dedicated to chromospheric observations with narrow band filters, the second one for photospheric obeservations with wide band filters, and the third one with the same filters, used out of focus for phase recostruction. The total number of foreseen filters will be 11, with bandpasses FWHM from 0.05 to 0.5 nm. The instrument will exploit the diffraction limited quality of the telescope, and will operate in two modalities: maximum field (2'x2'), and high resolution (better than 0.04" at 500nm).
Summary: Modification of the Hologgraphic Principle by the consideration of the emergence of Life and its consideration as an additional entropic Force to Gravity to yield Dark Matter contributions to the Force Law.
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
01.01.2023
Abstract:
By the emergence of life within Galaxies with strong Planet Formation Rates (PFR) of habitable and earth-like Planets, the possible interactions of life with itsels and the environment have to be considered as additional states within the Holographic Field. These additional states alter the overall Entropy within the Holographic Field and therefore the corresponding force law for gravity. The additional term can be interpreted as a Dark Matter contribution, as it adds up to the Newtonian law of gravity for normal baryonic matter.
Explaining the dynamics and the apparent distribution of Dark Matter of the Bullet Cluster by the consideration of a modified Holographic Principle.
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
11.03.2023
Abstract:
Current theories for Dark Matter are not possible to explain the distribution of Dark Matter (DM) within the Bullet Cluster that consists of former colliding Galaxy Clusters. Contradictory to the expected distribution of Dark Matter, whereas DM should be clumped at the location of the main visible baryonic mass distribution, the DM follows rather the mass distribution of the galaxy clusters.
With the assumption that the galaxies of the two colliding clusters possess a non-zero Planet Formation Rate (PFR) for habitable planets, as should be the case by the apparent mass-distributions of the galaxies, then the appearance and distribution of Dark Matter of the Bullet Cluster can be explained by the consideration of a modified Holographic Principle - for reference see other Posters by C. Nutto.
Deriving Dark Matter contributions by the consideration of a modified Holographic Principle for Galaxies with strong Planet Formation Rates (PFR) for habitable and earth-like Planets.
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
01.01.2023
Abstract:
By the emergence of life within a Galaxy, which is linked to the Planet Formation Rate (PFR) for habitable/earth-like Planets, the Entropy and hence the entropic Force for Gravity is altered by the consideration of additionial states within the Holographic Field due to the presence of life and its interaction with itself and the environment. The extra force term can be interpreted as Dark Matter contributions.
Evolution of Coronal Jets during Solar Cycle 24
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
26.09.2023
Co-author:
J. Liu (刘佳佳), M. B. Korsós, R. Erdélyi
Abstract:
The focus of this study is on the spatial and temporal distributions of 2704 solar jets throughout Solar Cycle 24, from beginning to end. This work is a follow up paper of Liu et al. (2023). With this extended dataset, we have further confirmed the two distinct distributions of coronal jets: one located in polar regions and another at lower latitudes. Further analysis of the series of coronal jets revealed kink oscillations of the global solar magnetic field. Additionally, studying the northern and southern hemispheres separately showed an anti-phase correlation that can be interpreted as a global sausage oscillatory pattern of the locii of the coronal jets. We also investigated how the variability of the solar cycle may impact the power law index of coronal jets by dividing the dataset into the rising and declining phases of Solar Cycle 24. Finally, we searched for compelling signatures of the presence of active longitude in the coronal jet database.
Confinedness of an X3.1 class solar flare occurred in NOAA 12192: Analysis from multi-instrument observations
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
05.07.2023
Co-author:
Prof. Francesca Zuccarello, Mrs Fabiana Ferrente and Dr Salvo Guglielmino
Abstract:
The non-association of coronal mass ejections with high energetic flares is sparse. For this reason, the magnetic conditions required for the confinedness of major flares is a topic of active research. Using multi-instrument observations, we investigated the evolution and effects of confinedness in an X3.1 flare, which occurred in active region (AR) 12192. The brightenings and decrease of net fluxes near the footpoints of the multi-sigmoidal AR in photosphere and chromosphere, indicative of flux cancellation favouring tether-cutting reconnection (TCR), is observed using the magnetic field observations of HMI/SDO and SOT/Hinode, respectively. The analysis of spectropolarimetric data obtained by the Interferometric Bidimensional Spectrometer over the brightening regions suggests untwisting of field lines, which further supports TCR. Filaments near polarity inversion line region, resulted from TCR of low lying sheared loops, undergo merging and form an elongated filament. The temperature
SolarLab as Pathfinder towards SPRING
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
24.07.2023
Co-author:
Markus Roth, Dirk Soltau, Michael Sigwarth, Hans-Peter Doerr, Aashana Tripathi
Abstract:
SolarLab is a container-based observatory for full disk observations of the Sun, to be installed and operated on site of the Thüringer Landessternwarte Tautenburg (TLS). It will be used as a laboratory
for instrument development and scientific observations, the requirements for which are derived from SPRING – an envisioned global network of synoptic solar telescopes. The primary instrument is a large tunable Fabry-Pérot interferometer based 2-D spectropolarimeter.
Mysterious motion of penumbral grains
Natural Sciences (Astrophysics and Astrononmy)
Date of upload:
19.09.2023
Co-author:
Jan Jurčák, Marta García Rivas
Abstract:
Bright heads of penumbral filaments, penumbral grains (PGs), move toward the umbra (inwards) in the inner penumbra and away from the umbra (outwards) in the outer penumbra. In a model by Tiwari et al. (2013, A&A 557, A25), penumbral filaments are magnetoconvective cells distributed everywhere in the penumbra and embedded in a background magnetic field whose inclination increases with the distance from the umbra. Sobotka & Puschmann (2022, A&A 662, A13) have shown that PGs motions change their orientation from inwards to outwards in the middle penumbra and their outward speed gradually increases with distance in the outer penumbra. We use spectropolarimetric observations of sunspot penumbrae to compare magnetic inclinations inside PGs with those in their surroundings. We show that inward-moving PGs mostly have magnetic inclination larger than that in the surroundings and the inclination in outward-moving PGs is usually smaller than the surrounding one.
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