A Decade of Astronomical Surprises (1960–1969)

Andersen, J.; Baneke, David; Madsen, C.

doi:10.1007/978-3-319-96965-7_3

Cited by 3 publications

(3 citation statements)

References 5 publications

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“…Another possibility is that the corona is a hybrid plasma system, where the presence of a population of non-thermal electrons can act to reduce the temperature of the plasma. Future studies that can apply advanced hybrid plasma models to high quality broadband AGN X-ray spectral observations performed with NuSTAR or concept X-ray missions such as HEX-P (Madsen et al 2019), may be able to robustly test the possibility of such a physical scenario producing a low temperature corona.…”

Section: Discussionmentioning

confidence: 99%

X-ray Coronal Properties of Swift/BAT-Selected Seyfert 1 Active Galactic Nuclei

Kamraj,

Brightman,

Harrison

et al. 2022

Preprint

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The corona is an integral component of Active Galactic Nuclei (AGN) which produces the bulk of the X-ray emission above 1-2 keV. However, many of its physical properties and the mechanisms powering this emission remain a mystery. In particular, the temperature of the coronal plasma has been difficult to constrain for large samples of AGN, as constraints require high quality broadband Xray spectral coverage extending above 10 keV in order to measure the high energy cutoff, which provides constraints on the combination of coronal optical depth and temperature. We present constraints on the coronal temperature for a large sample of Seyfert 1 AGN selected from the Swift/BAT survey using high quality hard X-ray data from the NuSTAR observatory combined with simultaneous soft X-ray data from Swift/XRT or XMM-Newton. When applying a physically-motivated, non-relativistic disk reflection model to the X-ray spectra, we find a mean coronal temperature kT e = 84±9 keV. We find no significant correlation between the coronal cutoff energy and accretion parameters such as the Eddington ratio and black hole mass. We also do not find a statistically significant correlation between the X-ray photon index, Γ, and Eddington ratio. This calls into question the use of such relations to infer properties of supermassive black hole systems.

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Section: Discussionmentioning

confidence: 99%

X-ray Coronal Properties of Swift/BAT-Selected Seyfert 1 Active Galactic Nuclei

Kamraj,

Brightman,

Harrison

et al. 2022

Preprint

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“…We considered exposure times between 100 ks and 1 Ms. We have also considered datasets complemented by the INTEGRAL/ISGRI observations in the 20-250 keV range with the same exposure times, however, the results were similar to those for NICER and NuSTAR without INTEGRAL. While the exposure time of 1 Ms is not realistic, it allows us to consider higher quality data which may be available with future instruments, in particular with HEX-P, with its planned improvement in sensitivity by over an order of magnitude over NuSTAR (Madsen et al 2019).…”

Section: Modelmentioning

confidence: 99%

Improved model of X-ray emission from hot accretion flows

Niedźwiecki,

Szanecki,

Zdziarski

et al. 2022

Preprint

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We have developed an improved model of X-ray emission from optically thin, two-temperature accretion flows, kerrflow, using an exact Monte Carlo treatment of global Comptonization as well as with a fully general relativistic description of both the radiative and hydrodynamic processes. It also includes pion-decay electrons, whose synchrotron emission dominates the seed photons yield at Ṁ / ṀEdd 0.1 in flows around supermassive black holes. We consider in detail the dependence of the model spectra on the black hole spin, the electron heating efficiency, the plasma magnetization and the accretion rate, and we discuss feasibility of constraining these parameters by analyzing X-ray spectra of nearby low-luminosity active galactic nuclei. We note some degeneracies which hinder precise estimations of these parameters when individual X-ray spectra are analyzed. These degeneracies are eliminated when several spectra from a given source are fitted jointly, which then allows us to reliably measure the model parameters. We find significant differences with previous spectral models of hot-flow emission, related with the computational methods for Comptonization. Finally, we briefly consider and discuss the dependence on the viscosity parameter and on the outflow strength.1 the xspec implementation of our code can be downloaded at wfis.uni.lodz.pl/kerrflow

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“…Betegnelserne "livstykke" og "snøreliv" kendes begge fra danske 1500-tals kilder, i 1548 naevnes et snøreliv snøret med bånd. 30 Der er bevaret flere dragtdele fra 1700-tallet og frem med snørehuller eller påsyede snøreringe. 31 I kunsten ses snøreliv ofte gengivet, f.eks.…”

Section: Snøreendedupperunclassified

Snøreendedupper og snørenåle – Krop, køn og mode i senmiddelalder og nyere tid

Søvsø¹

2014

Kuml

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Lace tags and bodkins Body, gender and fashion in Late Medieval and Modern TimesChanges in fashion beginning in the middle of the 14th century led to the employment of new kinds of dress accessories. Costumes for both men and women had to be close-fitting and use was made of buttons, hooks and eyelets and laces or drawstrings to close the long vents (fig. 8). Of these items, metal tags from corset laces occur most frequently as both archaeological and metal-detector finds in Sydvestjyske Museer’s area. These tags prevented the ends of the laces from fraying and made it easier to thread them through the lace holes.The tags fall into two general types that have the same function but differ in form and date (fig. 1). The earliest type comprises the tubular or conical tags found in Ribe’s medieval layers from the 13th-16th centuries (cat. nos. 1‑18) (fig. 2). Many of these have preserved remnants of laces and the rivets that secured these (figs. 3 and 4). The second type, known as a bodkin, was probably developed to be fitted to chains in corsets in post-Reformation times (cat. nos. 19‑25) (fig. 6).The archaeological finds from Ribe are from both secular and ecclesiastical contexts, but they are too few in number to permit anything more to be said on the significance of context. It can, however, be concluded, on the basis of archaeological finds from the town and metal-detector finds from Ribe’s hinterland, that both the urban and rural population made use of these laces.Laces with tags were employed in the upper part of the costumes of both men and women (fig. 9, 11‑18), in men’s hose and codpieces and in knights’ doublets. Although they occur in the archaeological record as early as the Early Middle Ages, and are particularly evident from the 14th century onwards, they do not feature in medieval art to any great extent until the beginning of the 15th century. There are then, however, a large number of good examples illustrating the use of corsets in all layers of society (fig. 9, 11‑18) and, in many cases, these play on the piquant symbolism associated with the lacing up and emphasis of certain parts of the body (figs. 13, 14 and 17). The pictorial sources also contain a great deal of information on the appearance of laces and on lacing methods, and in some cases the tags are also visible.Tags and bodkins are found together in 17th century hoards (fig. 8) and they were probably both still in use long after the Reformation. Bodkins are seen depicted in art as late as the 19th century, where peasant girls wear chains and corsets with bodkins (fig. 20). This is just one example of medieval types of costume accessories that continued in use, in a slightly altered form, well into recent times. These objects are in themselves modest, but in conjunction with written and pictorial sources they provide tangible evidence of the use of an artefact type that, over and above a practical role in dress from the 14th century onwards, also supplies information on body ideals, the joy of dressing up and sensuality.Mette Højmark SøvsøSydvestjyske Museer

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A Decade of Astronomical Surprises (1960–1969)

Cited by 3 publications

References 5 publications

X-ray Coronal Properties of Swift/BAT-Selected Seyfert 1 Active Galactic Nuclei

X-ray Coronal Properties of Swift/BAT-Selected Seyfert 1 Active Galactic Nuclei

Improved model of X-ray emission from hot accretion flows

Snøreendedupper og snørenåle – Krop, køn og mode i senmiddelalder og nyere tid

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