Massive Black Hole Mass Research Articles

Accretion efficiency at the Eddington luminous stage in quasars

Abstract Non-steady and eruptive phenomena in quasars are thought to be associated with the Eddington or super-Eddington luminous stage. Although there is no lack of hypotheses about the total duration of such a stage, the latter remains essentially unknown. We calculate the duration of the quasar luminous stage as a function of the initial mass of a newborn massive black hole (MBH) by comparing the observed luminosity- and redshift distributions of quasars with the mass distribution of MBHs in normal galactic nuclei. It is assumed that, at the quasar stage, each MBH goes through a single (or recurrent) phase(s) of accretion with, or close to, the Eddington luminosity. The mass distributions of quasars is found to be connected with that of MBHs residing in normal galaxies by a single-valued relationship through the mass range 107−1011 M[odot] of the inferred MBHs.

The Constellation X-ray mission

Constellation-X combines both the large collecting area and sensitive spectrometers required to obtain high spectral resolution, broad bandpass (0.25—40 keV) spectroscopy for all classes of X-ray sources, over a wide range of luminosity and redshift. It represents a major advance in sensitivity, providing up to a factor of 100 increase in throughput over currently planned high resolution (R > 300) X-ray spectroscopy missions. Constellation-X is the X-ray equivalent of the Keck Telescope. When observations begin towards the end of the next decade, they will mark the start of a new era with high resolution X-ray spectra obtained for all classes of X-ray sources over a wide range of luminosity and distance. With its increased capabilities, Constellation-X will address many fundamental astrophysics questions such as observing the formation and evolution of clusters of galaxies; constraining the Baryon content of the Universe; determining the spin and mass of super massive black holes in AGN; and probing strong gravity in the vicinity of black holes.

The Constellation X‐ray mission

Constellation-X combines both the large collecting area and sensitive spectrometers required to obtain high spectral resolution, broad bandpass (0.25—40 keV) spectroscopy for all classes of X-ray sources, over a wide range of luminosity and redshift. It represents a major advance in sensitivity, providing up to a factor of 100 increase in throughput over currently planned high resolution (R > 300) X-ray spectroscopy missions. Constellation-X is the X-ray equivalent of the Keck Telescope. When observations begin towards the end of the next decade, they will mark the start of a new era with high resolution X-ray spectra obtained for all classes of X-ray sources over a wide range of luminosity and distance. With its increased capabilities, Constellation-X will address many fundamental astrophysics questions such as observing the formation and evolution of clusters of galaxies; constraining the Baryon content of the Universe; determining the spin and mass of super massive black holes in AGN; and probing strong gravity in the vicinity of black holes.

The Constellation X-ray mission

Constellation-X combines both the large collecting area and sensitive spectrometers required to obtain high spectral resolution, broad bandpass (0.25—40 keV) spectroscopy for all classes of X-ray sources, over a wide range of luminosity and redshift. It represents a major advance in sensitivity, providing up to a factor of 100 increase in throughput over currently planned high resolution (R > 300) X-ray spectroscopy missions. Constellation-X is the X-ray equivalent of the Keck Telescope. When observations begin towards the end of the next decade, they will mark the start of a new era with high resolution X-ray spectra obtained for all classes of X-ray sources over a wide range of luminosity and distance. With its increased capabilities, Constellation-X will address many fundamental astrophysics questions such as observing the formation and evolution of clusters of galaxies; constraining the Baryon content of the Universe; determining the spin and mass of super massive black holes in AGN; and probing strong gravity in the vicinity of black holes.

On Quasar Masses and Quasar Host Galaxies

The mass of massive black holes in quasar cores can be deduced using the typical velocities of Hb-emitting clouds in the Broad Line Region (BLR) and the size of this region. However, this estimate depends on various assumptions and is susceptible to large systematic errors. The Hb-deduced black hole mass in a sample of 14 bright quasars is found here to correlate with the quasar host galaxy luminosity, as determined with the Hubble Space Telescope (HST). This correlation is similar to the black hole mass vs. bulge luminosity correlation found by Magorrian et al. in a sample of 32 nearby normal galaxies. The similarity of the two correlations is remarkable since the two samples involve apparently different types of objects and since the black hole mass estimates in quasars and in nearby galaxies are based on very different methods. This similarity provides a ``calibration'' of the Hb-deduced black hole mass estimate, suggesting it is accurate to +-0.5 on log scale. The similarity of the two correlations also suggests that quasars reside in otherwise normal galaxies, and that the luminosity of quasar hosts can be estimated to +-0.5 mag based on the quasar continuum luminosity and the Hb line width. Future imaging observations of additional broad-line active galaxies with the HST are required in order to explore the extent, slope, and scatter of the black hole mass vs. host bulge luminosity correlation in active galaxies.

Jets and Transients

I have been asked to provide some general introduction to the topic of jets and high energy transients. I have chosen to do this by asking seven questions that seem to be timely following recent observational and theoretical developments, the most important of which may be the growing realization that the extragalactic- massive black hole and Galactic-stellar mass black hole manifestations of these phenomena provide two complementary ways of viewing a common physical mechanism. I have also chosen to illustrate these questions using one specific source in each case. The page limits prevent me from giving the answers. They also prohibit my even attempting to give a skeletal bibliography over so large a field. Fortunately almost all of these topics will be covered in greater depth during this meeting.

Turbulent accretion onto massive black holes

view Abstract Citations (38) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Turbulent accretion onto massive black hole. Maraschi, L. ; Perola, G. C. ; Reina, C. ; Treves, A. Abstract Turbulent spherical accretion onto massive black holes (masses of the order of 1 million to 1 billion solar masses) is considered. Temperatures of the order of 1 billion to 10 billion K are found in the inner zone, where the synchrotron frequencies are 10 to the 13th to 10 to the 14th Hz. If the optical depth of the hole atmosphere is about unity, Comptonization can produce a power-law spectrum of index about unity from the synchrotron frequencies up to medium X-rays. If the optical depth is greater than or about equal to unity, convection of radiation into the hole becomes important at small radii, reducing the efficiency of emission. The results are briefly compared with the observations. Publication: The Astrophysical Journal Pub Date: May 1979 DOI: 10.1086/157080 Bibcode: 1979ApJ...230..243M Keywords: Black Holes (Astronomy); Compton Effect; Radiation Spectra; Stellar Mass Accretion; Synchrotron Radiation; Bremsstrahlung; Convection; Gas Temperature; Optical Thickness; Temperature Profiles; Turbulence Effects; Astrophysics; Accretion:Black Holes full text sources ADS |