4,534 research outputs found
Low-luminosity AGN and Normal Galaxies
Low-luminosity AGN (with X-ray luminosity < 1e42 ergs/s) far outnumber
ordinary AGN, and are therefore perhaps more relevant to our understanding of
AGN phenomena and the relationship between AGN and host galaxies. Many normal
galaxies harbor LINER and starburst nuclei, which, together with LLAGN, are a
class of ``low-activity'' galaxies that have a number of surprisingly similar
X-ray characteristics, despite their heterogenous optical classification. This
strongly supports the hypothesis of an AGN-starburst connection. Further, X-ray
observations of normal galaxies without starburst or AGN-like activity in their
nuclei offer opportunities to study populations of X-ray binaries, HII regions,
and warm or hot ISM under different conditions than is often the case in the
Milky Way. The results of recent X-ray observations of these types of galaxies
are reviewed, and what we hope to learn about both nearby and high redshift
galaxies of each type from observations with forthcoming and planned satellites
is discussed.Comment: 10 pages, 7 figures. Invited review at Bologna X-ray Astronomy 1999.
To appear in Astrophysical Letters and Communication
Czy jesteśmy „społeczeństwem honoru”? Rekonstrukcja pojęcia honoru w wybranych orzeczeniach polskich sądów
The existence of honour as a particular value is not unique, restricted to the boundaries of certain states, nationalities or ethnicities only. Yet, a distinction can be found in the literature between so-called ‘societies of honour’ and ‘modernised societies’. It is believed that in ‘societies of honour’ honour plays a central role in regulating social relations, and in ‘modernised societies’ based on the rule of law its importance is marginalised. This article is a contribution to the discussion on the adequacy of the discussed division based on the example of Polish society. Due to the fact that an important feature of this distinction is the juxtaposition of law and honour as tools for regulating social relations, the starting point of the analysis of this issue is to answer the question whether the concept of ‘honour’ exists in Polish law, and if so, how it is defined and in what contexts it appears. Due to the complexity of this issue, the subject of the article was limited to a specific problem – the analysis of selected judgments of Polish courts and the reasons underlying these judgments. The research allowed to identify the provisions of Polish law which refer (or could refer) to honour. Based on the analysis made, it may be stated that both, judges as well as parties to court proceedings, consider honour as a protected, legally accepted value.Występowanie honoru jako pewnej szczególnej wartości nie jest czymś wyjątkowym, ograniczonym do granic określonych państw, narodowości czy etniczności. Mimo to w literaturze można odnaleźć rozróżnienie między tzw. społeczeństwami honoru i społeczeństwami zmodernizowanymi. Uważa się, że w „społeczeństwach honoru” honor pełni rolę głównego narzędzia regulacji stosunków społecznych, a w „społeczeństwach zmodernizowanych”, opartych na prawie, jego znaczenie jest zmarginalizowane. Niniejszy artykuł stanowi przyczynek do dyskusji nad adekwatnością omówionego podziału na przykładzie polskiego społeczeństwa. Z racji tego, że istotną cechą wskazanego rozróżnienia jest przeciwstawianie prawa i honoru jako narzędzi regulacji stosunków społecznych, punktem wyjścia analizy problemu jest udzielenie odpowiedzi na pytanie, czy w polskim prawie występuje pojęcie „honoru”, a jeżeli tak, jak jest definiowane i w jakim kontekście się pojawia. Ze względu na złożoność tej problematyki, temat artykułu został ograniczony do konkretnego problemu – analizy wybranych wyroków polskich sądów wraz z uzasadnieniami. Przeprowadzone badania pozwoliły na wskazanie przepisów polskiego prawa, które odnoszą się (albo mogą się odnosić) do honoru, a także na stwierdzenie, że zarówno przez sędziów, jak i przez strony postępowań sądowych honor jest uznawany za chronioną prawnie, powszechnie akceptowaną wartość
The Statistical Properties of Galaxies Containing ULXs
We present a statistical analysis of the properties of galaxies containing
ultraluminous X-ray objects (ULXs). Our primary goal is to establish the
fraction of galaxies containing a ULX as a function of ULX luminosity. Our
sample is based on ROSAT HRI observations of galaxies. We find that ~ 12% of
galaxies contain at least one ULX with L_X > 10^39 erg/s and ~ 1% of galaxies
contain at least one ULX with L_X > 10^40 erg/s. These ULX frequencies are
lower limits since ROSAT HRI observation would miss absorbed ULXs (i.e., with
N_H >~ 10^21 cm^-2) and those within ~ 10" of the nucleus (due to the
positional error circle of the ROSAT HRI). The Hubble type distribution of
galaxies with a ULX differs significantly from the distribution of types for
nearby RC3 galaxies, but does not differ significantly from the galaxy type
distribution of galaxies observed by the HRI in general. We find no increase in
the mean FIR luminosity or FIR / K band luminosity ratio for galaxies with a
ULX relative to galaxies observed by the HRI in general, however this result is
also most likely biased by the soft bandpass of the HRI and the relatively low
number of high SFR galaxies observed by the HRI with enough sensitivity to
detect a ULX.Comment: Accepted by Apj. 5 pages with 4 figures formatted using emulateapj.
Version with just b/w figures available at
http://www.pha.jhu.edu/~ptak/paper
--hyperreflexivity and hyporeflexivity of power partial isometries
Power partial isometries are not always hyperreflexive neither reflexive. In
the present paper it will be shown that power partial isometries are always
hyporeflexive and --hyperreflexive
The effect of suprathermal protons on the physical conditions in Seyfert galaxy nuclei
The physical conditions in a high density hydrogen gas heated and ionized by suprathermal protons were investigated, with application to the gas in the nuclear region of Seyfert galaxies. The gas is assumed optically thick to Lyman and Balmer line radiation. Mechanisms by which the radiation from the gas can balance the heating by the fast protons were investigated, and minimum values for the mass of gas were estimated. Under certain conditions, the suprathermal atoms themselves can cool the ambient gas by rescattering the line radiation into the optically thin region in the wings of the line. This mechanism, called optical reverberation, can enhance the broad component of the hydrogen lines produced by inelastic atomic collisions and yield line widths consistent with those observed in Seyfert and quasar spectra. Also discussed is the possibility of achieving dynamic equilibrium of the ambient gas by balancing the momentum transfer from the suprathermals with gravitational attraction of a massive central source
On the interpretation of FE 2 emission profiles in Seyfert galaxies and QSOs
High-resolution spectral scans of several QSOs and Seyfert galaxies show broad Balmer lines and permitted Fe II lines in emission. It is suggested that a careful comparison of the Fe II and Balmer profiles may distinguish between the different proposed mechanisms for broadening of the lines. In particular, if the Fe II profile is much narrower that the hydrogen profile, the suprathermal particle mechanism is most likely presented
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