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The advent of large integral field spectroscopic surveys has found that elliptical galaxies (EGs) can be divided into two classes: the fast rotators (whose kinematics are dominated by rotation) and the slow rotators (which exhibit slow or no rotation pattern). It is often suggested that while the slow rotators typically have boxy isophotal shapes, have a high α-to-iron abundance ratio, and are quite massive, the fast rotators often exhibit the opposite properties (that is, having disky isophotes, lower α-to-iron ratio, and of typical masses). Whether the EGs consist of two distinct populations (i.e., a dichotomy exists) remains an unsolved issue. To examine the existence of the dichotomy, we used a sample of 1895 EGs from the SDSS-IV MaNGA survey and measured robustly the stellar kinematics, isophotal shapes, and [Mg/Fe] ratio. We confirmed the previous finding that the bulk of the EGs are disky (65%) and fast rotators (67%), but we found no evidence supporting a dichotomy, based on a principal component analysis. The different classes (boxy/disky and slow/fast rotators) of EGs occupy slightly different loci in the principal component space. This may explain the observed trends that led to the premature support of a dichotomy based on small samples of galaxies.

We report on observations acquired by the Interferometric Bidimensional Spectropolarimeter (IBIS) during SOL2014-10-22T14:02, an X1.6 flare that occurred in active region NOAA 12192, taken in the Fe i 617.30 nm and Ca ii 854.2 nm line profiles. We analyze polarization signatures in the Stokes profiles of the two lines across one of the flare ribbons. Focusing our attention on the chromospheric signals and using the weak-field approximation (WFA), we study the temporal variation of the line-of-sight (LOS) magnetic field. We find variations of the magnetic field or the opacity along the flare ribbon, in most cases within the first 3 minutes of the observation just after the flare peak, during the tail of the flare impulsive phase. This result was validated by the STiC inversion of the pixels used for the WFA analysis. The analysis of the photospheric magnetic field shows that in this layer, the LOS magnetic field does not show the same changes observed in the chromosphere in the selected pixels, nor clear evidence of changes along the polarity inversion line around a magnetic polarity intrusion. In this respect, we also find that the temporal observing window is not suitable for assessing the presence of stepwise changes. The nonlinear force-free field extrapolations, together with the analysis of the ribbons’ isophotes obtained from Interface Region Imaging Spectrograph data, suggest that the region corresponding to the magnetic intrusion observed by IBIS is characterized by a complex magnetic connectivity and is almost cospatial with the area affected by the initial energy release.

We have examined the stellar structure of 10 nearby, low stellar mass (106–6 × 107 M⊙) dwarf irregular galaxies by fitting ellipses as a function of surface brightness on ultradeep V images. These are compared to far-ultraviolet images as tracers of the star formation. We find that the often asymmetrical distribution of large patches of star formation activity in dwarfs, even out to low disk surface brightness levels, skews the broad-band optical isophotes in these galaxies. We also looked for evidence of the presence of a stellar halo. Possible hints of such are found in several galaxies from irregularities in the ellipses, but a stack of seven of the galaxies shows a pure exponential out to a V surface brightness of 32.3 mag arcsec−2 where the stellar surface density is 0.0013 ± 0.0011 M⊙ pc−2. The extended stellar component, most likely a disk structure, is probably due to internal evolutionary processes rather than external accretion. The UBVI colors of the annuli are consistent with ages of 1–6 Gyr for the far outer stellar disk.

We present an analysis of the cluster X-ray morphology and active galactic nucleus (AGN) activity in nine z ∼ 1 galaxy clusters from the Massive and Distant Clusters of WISE Survey observed with Chandra. Using photon asymmetry (Aphot) to quantify X-ray morphologies, we find evidence that the four most dynamically disturbed clusters are likely to be mergers. Employing a luminosity cut of 7.6 × 1042 erg s−1 to identify AGNs in the 0.7–7.0 keV region, we show that the majority of these clusters host excess AGNs compared to the local field. We use the model of cumulative number counts ( logN−logS ) to predict AGN incidence in cluster isophotes under this luminosity cut. Our analysis finds evidence (at >2σ) of a positive correlation between AGN surface densities and photon asymmetry, suggesting that a disturbed cluster environment plays a pivotal role in regulating triggering of AGNs. Studying AGN incidence in cluster X-ray isophotes equivalent in area to 1.0r500, we find that the AGN space density inversely scales with cluster mass as ∼M−0.5−0.18+0.18 at the 3.18σ level. Finally, when we separately explore the cluster mass dependence of excess AGN surface density in disturbed and relaxed clusters, we see tentative evidence that the two morphologically distinct subpopulations exhibit diverging trends, especially near the outskirts, likely due to cluster merger-driven AGN triggering/suppression.

Zw 049.057 is a moderate-mass, dusty, early-type galaxy that hosts a powerful compact obscured nucleus (CON, L FIR,CON ≥ 1011 L ⊙). The resolution of the Hubble Space Telescope enabled measurements of the stellar light distribution and characterization of dust features. Zw 049.057 is inclined with a prominent three-zone disk; the R ≈ 1 kpc star-forming inner dusty disk contains molecular gas, a main disk with less dust and an older stellar population, and a newly detected outer stellar region at R > 6 kpc with circular isophotes. Previously unknown polar dust lanes are signatures of a past minor merger that could have warped the outer disk to near face-on. Dust transmission measurements provide lower limit gas mass estimates for dust features. An extended region with moderate optical depth and M ≥ 2 × 108 M ⊙ obscures the central 2 kpc. Optical spectra show strong interstellar Na D absorption with a constant velocity across the main disk, likely arising in this extraplanar medium. Opacity measurements of the two linear dust features, pillars, give a total mass of ≥106 M ⊙, flow rates of ≥2 M ⊙ yr−1, and few Myr flow times. Dust pillars are associated with the CON and are visible signs of its role in driving large-scale feedback. Our assessments of feedback processes suggest gas recycling sustains the CON. However, radiation pressure driven mass loss and efficient star formation must be avoided for the active galactic nucleus to retain sufficient gas over its lifespan to produce substantial mass growth of the central black hole.

We present results of isophotal shape analysis of an interesting elliptical galaxy NGC 5216 with a clear sign of merging activity with its companion galaxy NGC 5218. We have used r-bands image analysis of the galaxy from Sloan Digital Sky Survey Data Release 9 (i.e. SDSS DR9) to perform bulge-disk decomposition of the light profile of the galaxy. We look for the correlation between systematic departure of isophotes from pure ellipses along the semi-major axis of the galaxies. The contour image of the galaxy clearly indicates that stellar mass exchange is taking place via a star forming bridge. The estimated B/T value confirms its morphology as an elliptical galaxy.

The Ludendorff coronal flattening index is a quantitative parameter to analyze the global structure and shape of the corona. This index plays a crucial role in identifying solar magnetic activity and estimating the phase of the solar cycle. We observed a total solar eclipse on 20 April 2023 in Timor-Leste and obtained a Ludendorff coronal flattening index of 0.109 ± 0.025 by analyzing isophotes in white-light coronal images. Based on the composite image of the corona, streamers and plumes were observed extending in various directions across the solar disk, indicating that the Sun was in the ascending phase of its cycle. To establish the relationship between the coronal flattening index and the solar cycle phase, historical total solar eclipse data (1893 – 2013) were analyzed, focusing on smoothed sunspot numbers and flattening indices during the ascending phase. Two datasets, designated as “full” and “conservative”, were constructed considering temporal constraints relative to solar maxima and minima. The coronal morphology observed during the 20 April 2023 total solar eclipse corresponded to a premaximum phase, with values of 0.673 ± 0.172 and 0.613 ± 0.171 for the full and conservative datasets, respectively. We also developed a multilinear correlation and polynomial regression of second order models to predict the peak amplitude of the current solar cycle using both datasets. The full dataset predicted a peak on 3 December 2024 with amplitudes of 173 ± 23 and 163 ± 21 for the respective models. Conversely, the conservative dataset predicted a peak on 30 May 2025 with amplitudes of 180 ± 24 and 180 ± 25 for the respective models. These findings suggest that Solar Cycle 25 will likely be stronger than Solar Cycle 24.

We present a review of the observations of the solar F-corona from space with a special emphasis of the 25 years of continuous monitoring achieved by the LASCO-C2 and C3 coronagraphs. Our work includes images obtained by the navigation cameras of the Clementine spacecraft, the SECCHI/HI-1A heliospheric imager onboard STEREO-A, and the Wide Field Imager for Solar Probe onboard the Parker Solar Probe . The connection to the zodiacal light is considered based on ground- and space-based observations, prominently from the past Helios , IRAS, COBE, and IRAKI missions. The characteristic radiance profiles along the two symmetry axis of the “elliptically” shaped F-corona (aka equatorial and polar directions) follow power laws in the 5 ∘ – 50 ∘ range of elongation, with constant power exponents of −2.33 and −2.55. Both profiles connect extremely well to the corresponding standard profiles of the zodiacal light. The LASCO equatorial profile exhibits a shoulder implying a ≈ 17 % decrease of the radiance within ≈ 10 R ⊙ that may be explained by the disappearance of organic materials within 0.3 AU. LASCO detected for the first time a secular variation of the F-corona, an increase at a rate of 0.46% per year of the integrated radiance in the LASCO-C3 field of view. This is likely the first observational evidence of the role of collisions in the inner zodiacal cloud. The temporal evolution of the integrated radiance in the LASCO-C2 field of view is more complex suggesting possible additional processes. Whereas it is well established that the F-corona is slightly redder than the Sun, the spectral variation of its color index is not yet well established. A composite of C2 and C3 images produced the LASCO reference map of the radiance of the F-corona from 2 to 30 R ⊙ and, by combining with ground-based measurements, the LASCO extended map from 1 to 6 R ⊙ . An upper limit of 0.03 R ⊙ is obtained for the offset between the center of the Sun and that of the F-corona with a most likely value of zero. The flattening index of the F-corona starts from zero at an elongation of 0.5 ∘ ± 0.01 ∘ ( 1.9 R ⊙ ) and increases linearly with the logarithm of the elongation to connect to that of the zodiacal light with however a small hump related to the shoulder in the equatorial profile. The shape of the isophotes is best described by super-ellipses with an exponent linked to the flattening index. An ellipsoid model of the spatial density of interplanetary dust is solely capable of reproducing this shape, thus rejecting other classical models such as fan, and cosine. The plane of symmetry of the inner zodiacal cloud is strongly warped, its inclination increasing towards the planes of the inner planets and ultimately the solar equator. In contrast, its longitude of ascending node is found to be constant and equal to 87.6 ∘ . LASCO did not detect any small scale structures such as putative rings occasionally reported during solar eclipses. The outer border of the depletion zone where interplanetary dust particles start to be affected by sublimation appears well constrained at ≈ 19 R ⊙ . This zone extends down to ≈ 5 R ⊙ , thus defining the boundary of the dust-free zone where the most refractory materials – likely moderately absorbing silicates – disappear.

AbstractThe problems of the study of small celestial bodies are an important component of modern space research. This applies both to the study of physicochemical and evolutionary parameters and the search for the genetic relationships between meteor showers and their parent bodies. An important area of research is the structural analysis of comets and asteroids. The relevance of the study of comet bodies lies in the fact that comets contain information about the protosolar molecular cloud. Comet nuclei are solid bodies that consist of dust (silicates, polymers, polycyclic aromatic hydrocarbons, etc.) and ice of various compositions (water, carbon dioxide, carbon monoxide, methane, ammonia, etc.). Comet nuclei are fragile and have an irregular shape due to their low density, mass, and gravity. The study of the structural and physicochemical characteristics of comets is a relevant and important task for the development of an evolutionary theory. Using the developed method and special software for brightness analysis of digital images, we created structural models of comets and obtained brightness isophotes of their nuclei, heads, and tails. Since comet nuclei are elements of dynamic evolution and processes in the protodisk of the Solar System, study of the digital structure of comets will help improve the theory of the formation and evolution of the Solar System.

We use 101 galaxies selected from the Nearby Field Galaxy Survey to investigate the effect of aperture size on the star formation rate, metallicity, and reddening determinations for galaxies. Our sample includes galaxies of all Hubble types except ellipticals with global star formation rates (SFRs) ranging from 0.01 to 100M ⊙yr−1, metallicities in the range \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $7.9\\lesssim \\mathrm{log}\\,( \\mathrm{O}\\,/ \\mathrm{H}\\,) +12\\lesssim 9.0$ \\end{document} , and reddening of \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $0\\lesssim A( V) \\lesssim 3.3$ \\end{document} . We compare the SFR, metallicity, and reddening derived from nuclear spectra to those derived from integrated spectra. For apertures capturing <20% of the \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $B_{26}$ \\end{document} light, the differences between nuclear and global metallicity, extinction, and SFR are substantial. Late‐type spiral galaxies show the largest systematic difference (∼0.14 dex), with nuclear metallicities greater than the global metallicities. The Sdm, Im, and Peculiar types have the largest scatter in nuclear/integrated metallicities, indicating a large range in metallicity gradients for these galaxy types, or clumpy metallicity distributions. We find little evidence for systematic differences between nuclear and global extinction estimates for any galaxy type. However, there is significant scatter between the nuclear and integrated extinction estimates for nuclear apertures containing <20% of the \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $B_{26}$ \\end{document} flux. We calculate an “expected” SFR using our nuclear spectra and apply the commonly used aperture correction method. The expected SFR overestimates the global value for early‐type spirals, with large scatter for all Hubble types, particularly late types. The differences between the expected and global SFRs probably result from the assumption that the distributions of the emission‐line gas and the continuum are identical. The largest scatter (error) in the estimated SFR occurs when the aperture captures <20% of the \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $B_{26}$ \\end{document} emission. We discuss the implications of these results for metallicity‐luminosity relations and star formation history studies based on fiber spectra. To reduce systematic and random errors from aperture effects, we recommend selecting samples with fibers that capture >20% of the galaxy light. For the Sloan Digital Sky Survey and the Two‐Degree Field Galaxy Redshift Survey, redshifts \\documentclass{aastex} \\usepackage{amsbsy} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{bm} \\usepackage{mathrsfs} \\usepackage{pifont} \\usepackage{stmaryrd} \\usepackage{textcomp} \\usepackage{portland,xspace} \\usepackage{amsmath,amsxtra} \\usepackage[OT2,OT1]{fontenc} \\newcommand\\cyr{ \\renewcommand\\rmdefault{wncyr} \\renewcommand\\sfdefault{wncyss} \\renewcommand\\encodingdefault{OT2} \\normalfont \\selectfont} \\DeclareTextFontCommand{\\textcyr}{\\cyr} \\pagestyle{empty} \\DeclareMathSizes{10}{9}{7}{6} \\begin{document} \\landscape $z> 0.04$ \\end{document} and 0.06 are required, respectively, to ensure a covering fraction >20% for galaxy sizes similar to the average size, type, and luminosity observed in our sample. Higher luminosity samples and samples containing many late‐type galaxies require a larger minimum redshift to ensure that >20% of the galaxy light is enclosed by the fiber.