New insights into AGNs with low-mass black holes and high accretion rates: the case of narrow-line Seyfert 1 galaxies

2010 ◽  
Vol 53 (S1) ◽  
pp. 216-219 ◽  
Author(s):  
DaWei Xu ◽  
S. Komossa
Keyword(s):  
Black Holes ◽  
Narrow Line ◽  
Accretion Rates ◽  
Low Mass

scholarly journals Low-Mass AGN at High Accretion Rates

2009 ◽  
Vol 5 (S267) ◽  
pp. 338-338
Author(s):  
Dawei Xu ◽  
S. Komossa
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galaxies ◽  
Narrow Line ◽  
Accretion Rates ◽  
Black Hole Growth ◽  
Low Mass ◽  
Hole Growth

AbstractGalaxies with low-mass black holes and high accretion rates, i.e., narrow-line Seyfert 1 (NLS1) galaxies, are important objects when addressing the issues of black hole growth and evolution, and of feeding and feedback. We have studied a sample of such objects, and find (1) that the locus of NLS1 galaxies on the MBH–σ plane appears to follow the relation of non-active galaxies after removing objects obviously dominated by outflows, (2) the presence of “blue outliers” that hint at extreme outflows as predicted by recent merger models, and (3) more subtle evidence for winds/outflows across the whole NLS1 population.

scholarly journals Ultrasoft Narrow-line Seyfert 1 Galaxies: An Extreme of Accretion onto Supermassive Black Holes

2000 ◽  
Vol 195 ◽  
pp. 207-208
Author(s):  
W. N. Brandt
Keyword(s):  
Black Holes ◽  
Supermassive Black Holes ◽  
High Mass ◽  
General Context ◽  
Narrow Line ◽  
X Ray ◽  
Basic Properties ◽  
The Future ◽  
Accretion Rates ◽  
New Phenomena

X-ray studies of ultrasoft narrow-line Seyfert 1 galaxies are revealing surprising new phenomena that are expanding our understanding of Seyfert activity, and they may well allow us to observe the effects of high mass accretion rates onto supermassive black holes. I briefly review the basic properties of these galaxies, their importance in a general context, and the prospects for studying them further in the future.

scholarly journals Relativistic Fe Kα line and ensemble spins of black holes in narrow-line Seyfert 1 galaxies

2014 ◽  
Vol 10 (S312) ◽  
pp. 39-42
Author(s):  
Weimin Yuan ◽  
Zhu Liu ◽  
Youjun Lu ◽  
Xin-Lin Zhou
Keyword(s):  
Black Holes ◽  
Seyfert Galaxies ◽  
Emission Feature ◽  
Narrow Line ◽  
Massive Black Holes ◽  
X Ray ◽  
Accretion Rates ◽  
Black Hole Growth ◽  
Average Spin ◽  
Hole Growth

AbstractWhile a broad line of the Fe Kα emission is commonly found in the X-ray spectra of typical Seyfert galaxies, the situation is unclear in the case of Narrow Line Seyfert 1 galaxies (NLS1s)—an extreme subset which are generally thought to harbor less massive black holes with higher accretion rates. We report results of our study of the assemble property of the Fe K line in NLS1s by stacking the X-ray spectra of a large sample of 51 NLS1s observed with XMM-Newton. We find in the stacked X-ray spectra a prominent, broad emission feature over 4–7 keV, which is characteristic of the broad Fe Kα line. Our results suggest that a relativistic broad Fe line may in fact be common in NLS1s. The line profile is used to study the average spin of the black holes in the sample. We find, for the first time, that their black holes are constrained to be likely spinning at averagely low or moderate rates as a population. The implications of the results are discussed in the context of the black hole growth in NLS1 galaxies.

scholarly journals Are Narrow-line Seyfert 1 Galaxies Powered by Low-mass Black Holes?

2019 ◽  
Vol 881 (1) ◽  
pp. L24 ◽  
Author(s):  
Gayathri Viswanath ◽  
C. S. Stalin ◽  
Suvendu Rakshit ◽  
Kshama S. Kurian ◽  
K. Ujjwal ◽  
...  
Keyword(s):  
Black Holes ◽  
Narrow Line ◽  
Low Mass

scholarly journals A Link Between Seyfert Emission-Line Widths and X-Ray Continuum Slopes

1997 ◽  
Vol 159 ◽  
pp. 248-251
Author(s):  
Th. Boile ◽  
W.N. Brandt
Keyword(s):  
Black Holes ◽  
Power Law ◽  
Optical Emission ◽  
Emission Lines ◽  
Narrow Line ◽  
Rapid Variability ◽  
X Ray ◽  
Accretion Rates ◽  
Line Widths ◽  
Almost All

AbstractThis paper reports on AGN with extremely soft X-ray spectra observed with ROSAT. From their optical emission lines, these objects are classified as narrow-line Seyfert 1 galaxies (NLSl), almost all with extremely large Fe II/Hβ flux ratios and relatively narrow optical lines of hydrogen. NLSl have generally steeper soft X-ray continuum slopes than normal Seyfert 1s, and there may exist an anticorrelation between 0.1–2.4 keV continuum slope and the FWHM of the Hβ line. Objects with steep 0.1–2.4 keV continuum slopes and Hβ FWHM > 3000 km s−1 are clearly discriminated against by nature. When simple power-law models are fit to the data, photon indices reach values up to about 5, much higher than is usually seen in Seyfert 1s. Models with smaller-mass black holes and/or higher accretion rates show some promise to explain the relation between the FWHM of the Hβ line and the X-ray continuum slope. We further report evidence for persistent giant and rapid variability in the ultrasoft narrow-line Seyfert 1 galaxy IRAS 13224–3809.

scholarly journals The Observational Evidence for Accretion

1997 ◽  
Vol 182 ◽  
pp. 391-405 ◽  
Author(s):  
Lee Hartmann
Keyword(s):  
Large Range ◽  
Observational Evidence ◽  
Young Stars ◽  
Young Stellar Objects ◽  
Stellar Objects ◽  
T Tauri ◽  
Accretion Rates ◽  
Low Mass ◽  
Stellar Magnetospheres ◽  
Mass Ejection

Outflows from low-mass young stellar objects are thought to draw upon the energy released by accretion onto T Tauri stars. I briefly summarize the evidence for this accretion and outline present estimates of mass accretion rates. Young stars show a very large range of accretion rates, and this has important implications for both mass ejection and for the structure of stellar magnetospheres which may truncate T Tauri disks.

scholarly journals Feeding and feedback from little monsters: AGN in dwarf galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 238-242
Author(s):  
Mar Mezcua
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Early Universe ◽  
Dwarf Galaxies ◽  
Scaling Relations ◽  
Strong Impact ◽  
Hole Formation ◽  
Intermediate Mass ◽  
Black Hole Formation ◽  
Low Mass

AbstractDetecting the seed black holes from which quasars formed is extremely challenging; however, those seeds that did not grow into supermassive should be found as intermediate-mass black holes (IMBHs) of 100 – 105 M⊙ in local dwarf galaxies. The use of deep multiwavelength surveys has revealed that a population of actively accreting IMBHs (low-mass AGN) exists in dwarf galaxies at least out to z ˜3. The black hole occupation fraction of these galaxies suggests that the early Universe seed black holes formed from direct collapse of gas, which is reinforced by the possible flattening of the black hole-galaxy scaling relations at the low-mass end. This scenario is however challenged by the finding that AGN feedback can have a strong impact on dwarf galaxies, which implies that low-mass AGN in dwarf galaxies might not be the untouched relics of the early seed black holes. This has important implications for seed black hole formation models.

scholarly journals The radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 in a galaxy merger

2020 ◽  
Vol 496 (2) ◽  
pp. 1757-1765 ◽  
Author(s):  
Akihiro Doi ◽  
Motoki Kino ◽  
Nozomu Kawakatu ◽  
Kazuhiro Hada
Keyword(s):  
Black Holes ◽  
Near Infrared ◽  
Gamma Ray ◽  
Linear Structure ◽  
Seyfert Galaxies ◽  
Mass Function ◽  
High Mass ◽  
Host Galaxy ◽  
Supporting Evidence ◽  
Narrow Line

ABSTRACT The supermassive black holes (SMBHs) of narrow-line Seyfert 1 galaxies (NLS1s) are at the lower end of the mass function of active galactic nuclei (AGNs) and reside preferentially in late-type host galaxies with pseudobulges, which are thought to be formed by internal secular evolution. On the other hand, the population of radio-loud NLS1s presents a challenge for the relativistic jet paradigm, which states that powerful radio jets are associated exclusively with very high mass SMBHs in elliptical hosts, which are built up through galaxy mergers. We investigated distorted radio structures associated with the nearest gamma-ray-emitting, radio-loud NLS1, 1H 0323+342. This provides supporting evidence for the merger hypothesis based on past optical/near-infrared observations of its host galaxy. The anomalous radio morphology consists of two different structures: the inner curved structure of the currently active jet and an outer linear structure of low-brightness relics. Such coexistence might be indicative of the stage of an established black hole binary with precession before the black holes coalesce in the galaxy merger process. 1H 0323+342 and other radio-loud NLS1s under galaxy interactions may be extreme objects on the evolutionary path from radio-quiet NLS1s to normal Seyfert galaxies with larger SMBHs in classical bulges through mergers and merger-induced jet phases.

scholarly journals The formation of high-mass black holes in low-mass X-ray binaries

New Astronomy ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. 313-323 ◽  
Author(s):  
G.E. Brown ◽  
C.-H. Lee ◽  
Hans A. Bethe
Keyword(s):  
Black Holes ◽  
High Mass ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries
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