Matches in SemOpenAlex for { <https://semopenalex.org/work/W2164887480> ?p ?o ?g. }
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- W2164887480 abstract "We discuss mm-wavelength radio, 2.2–11.8 <i>μ<i/>m NIR and 2–10 keV X-ray light curves of the super massive black hole (SMBH) counterpart of Sagittarius A* (SgrA*) near its lowest and highest observed luminosity states. We investigate the structure and brightness of the central S-star cluster harboring the SMBH to obtain reliable flux density estimates of SgrA* during its low luminosity phases. We then discuss the physical processes responsible for the brightest flare as well as the faintest flare or quiescent emission in the NIR and X-ray domain. To investigate the low state of SgrA* we use three independent methods to remove or strongly suppress the flux density contributions of stars in the central 2´´ diameter region around SgrA*. The three methods are: a) low-pass filtering the image; b) iterative identification and removal of individual stars; c) automatic point spread function (PSF) subtraction. For the lowest observed flux density state all 3 image reduction methods result in the detection of faint extended emission with a diameter of 0.5´´–1.0´´ and centered on the position of SgrA*. We analyzed two datasets that cover the lowest luminosity states of SgrA* we observed to date. In one case we detect a faint <i>K<i/>-band (2.2 <i>μ<i/>m) source of ~4 mJy brightness (de-reddened with <i>A<sub>K<sub/><i/> = 2.8) which we identify as SgrA* in its low state. In the other case no source brighter or equal to a de-reddened <i>K<i/>-band flux density of ~2 mJy was detected at that position. As physical emission mechanisms for SgrA* we discuss bremsstrahlung, thermal emission of a hypothetical optically thick disk, synchrotron and synchrotron self-Compton (SSC) emission, and in the case of a bright flare the associated radio response due to adiabatic expansion of the synchrotron radiation emitting source component. The luminosity during the low state can be interpreted as synchrotron emission from a continuous or even spotted accretion disk. For the high luminosity state SSC emission from THz peaked source components can fully account for the flux density variations observed in the NIR and X-ray domain. We conclude that at near-infrared wavelengths the SSC mechanism is responsible for all emission from the lowest to the brightest flare from SgrA*. For the bright flare event of 4 April 2007 that was covered from the radio to the X-ray domain, the SSC model combined with adiabatic expansion can explain the related peak luminosities and different widths of the flare profiles obtained in the NIR and X-ray regime as well as the non detection in the radio domain." @default.
- W2164887480 created "2016-06-24" @default.
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- W2164887480 date "2010-03-01" @default.
- W2164887480 modified "2023-10-16" @default.
- W2164887480 title "The extreme luminosity states of Sagittarius A*" @default.
- W2164887480 cites W1572145964 @default.
- W2164887480 cites W1624029523 @default.
- W2164887480 cites W1963609669 @default.
- W2164887480 cites W1966374563 @default.
- W2164887480 cites W1966839961 @default.
- W2164887480 cites W1968233816 @default.
- W2164887480 cites W1971173749 @default.
- W2164887480 cites W1972387309 @default.
- W2164887480 cites W1978003452 @default.
- W2164887480 cites W1979718451 @default.
- W2164887480 cites W1979760997 @default.
- W2164887480 cites W1984617300 @default.
- W2164887480 cites W1984902361 @default.
- W2164887480 cites W1992521049 @default.
- W2164887480 cites W1993057133 @default.
- W2164887480 cites W2001876144 @default.
- W2164887480 cites W2003155983 @default.
- W2164887480 cites W2006486232 @default.
- W2164887480 cites W2008483349 @default.
- W2164887480 cites W2009399083 @default.
- W2164887480 cites W2015110015 @default.
- W2164887480 cites W2016552132 @default.
- W2164887480 cites W2020570321 @default.
- W2164887480 cites W2026818944 @default.
- W2164887480 cites W2031178783 @default.
- W2164887480 cites W2031673053 @default.
- W2164887480 cites W2035654465 @default.
- W2164887480 cites W2038551992 @default.
- W2164887480 cites W2039821208 @default.
- W2164887480 cites W2040414328 @default.
- W2164887480 cites W2047891905 @default.
- W2164887480 cites W2048657385 @default.
- W2164887480 cites W2050551037 @default.
- W2164887480 cites W2053230585 @default.
- W2164887480 cites W2057023417 @default.
- W2164887480 cites W2057194537 @default.
- W2164887480 cites W2059171784 @default.
- W2164887480 cites W2064321817 @default.
- W2164887480 cites W2066404575 @default.
- W2164887480 cites W2080600720 @default.
- W2164887480 cites W2081911925 @default.
- W2164887480 cites W2081951835 @default.
- W2164887480 cites W2085431565 @default.
- W2164887480 cites W2085683239 @default.
- W2164887480 cites W2088909704 @default.
- W2164887480 cites W2089142505 @default.
- W2164887480 cites W2091108478 @default.
- W2164887480 cites W2091306090 @default.
- W2164887480 cites W2097618194 @default.
- W2164887480 cites W2107712658 @default.
- W2164887480 cites W2108290111 @default.
- W2164887480 cites W2109003813 @default.
- W2164887480 cites W2110284565 @default.
- W2164887480 cites W2114715442 @default.
- W2164887480 cites W2119586222 @default.
- W2164887480 cites W2123710893 @default.
- W2164887480 cites W2127554207 @default.
- W2164887480 cites W2128881761 @default.
- W2164887480 cites W2129923407 @default.
- W2164887480 cites W2130468066 @default.
- W2164887480 cites W2133623890 @default.
- W2164887480 cites W2133776028 @default.
- W2164887480 cites W2133983488 @default.
- W2164887480 cites W2134295769 @default.
- W2164887480 cites W2142889681 @default.
- W2164887480 cites W2143440443 @default.
- W2164887480 cites W2148421284 @default.
- W2164887480 cites W2152327544 @default.
- W2164887480 cites W2157058681 @default.
- W2164887480 cites W2162073826 @default.
- W2164887480 cites W2165875176 @default.
- W2164887480 cites W3011090980 @default.
- W2164887480 cites W3098656872 @default.
- W2164887480 cites W3098690306 @default.
- W2164887480 cites W3098774414 @default.
- W2164887480 cites W3098823048 @default.
- W2164887480 cites W3098908172 @default.
- W2164887480 cites W3099961299 @default.
- W2164887480 cites W3099977808 @default.
- W2164887480 cites W3100284380 @default.