scholarly journals CHANDRAAND MMT OBSERVATIONS OF LOW-MASS BLACK HOLE ACTIVE GALACTIC NUCLEI ACCRETING AT LOW RATES IN DWARF GALAXIES

2014 ◽  
Vol 782 (1) ◽  
pp. 55 ◽  
Author(s):  
W. Yuan ◽  
H. Zhou ◽  
L. Dou ◽  
X.-B. Dong ◽  
X. Fan ◽  
...  
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Dwarf Galaxies ◽  
Galactic Nuclei ◽  
Low Mass

scholarly journals A search for H2O masers in 100 active dwarf galaxies

2020 ◽  
Vol 499 (1) ◽  
pp. 1233-1249
Author(s):  
M J Rosenthal ◽  
I Zaw
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Detection Rate ◽  
Dwarf Galaxies ◽  
Galactic Nuclei ◽  
Optical Emission ◽  
Massive Black Hole ◽  
Massive Galaxies ◽  
Low Mass ◽  
Green Bank Telescope

ABSTRACT We present the results of the first dedicated survey for 22 GHz H2O maser emission in dwarf galaxies outside of the Local Group, with the aim of discovering disc masers. Studies of disc masers yield accurate and precise measurements of black hole (BH) mass, and such measurements in dwarf galaxies would be key to understanding the low-mass end of BH–galaxy coevolution. We used the Green Bank Telescope to survey 100 nearby (z ≲ 0.055) dwarf galaxies (M* ≲ 109.5 M⊙) with optical emission line ratios indicative of accretion on to a massive black hole. We detected no new masers down to a limit of ∼12 mJy (5σ). We compared the properties of our sample with those of ∼1850 known detections and non-detections in massive galaxies. We find, in agreement with previous studies, that masers are preferentially hosted by Seyferts and highly obscured, [O iii]-bright active galactic nuclei (AGNs). Our sample has fewer Seyferts, is less obscured, and is [O iii]-faint. Though the overall maser detection rate is ∼3 per cent in massive galaxies, the predicted rate for our sample, weighted by its optical properties, is ∼0.6–1.7 per cent, corresponding to a probability of making no detections of ∼20–50 per cent. We also found a slight increase in the detection rate with increased stellar mass in previously surveyed galaxies. However, further observations are required to discern whether there is an intrinsic difference between the maser fraction in active dwarf galaxies and in their massive counterparts for the same AGN properties.

scholarly journals ON THE BLACK HOLE MASS—X-RAY EXCESS VARIANCE SCALING RELATION FOR ACTIVE GALACTIC NUCLEI IN THE LOW-MASS REGIME

2015 ◽  
Vol 808 (2) ◽  
pp. 163 ◽  
Author(s):  
Hai-Wu Pan ◽  
Weimin Yuan ◽  
Xin-Lin Zhou ◽  
Xiao-Bo Dong ◽  
Bifang Liu
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Scaling Relation ◽  
Black Hole Mass ◽  
X Ray ◽  
Low Mass

scholarly journals Environments of dwarf galaxies with optical AGN characteristics

2020 ◽  
Vol 496 (3) ◽  
pp. 2577-2590 ◽  
Author(s):  
Mikkel T Kristensen ◽  
Kevin Pimbblet ◽  
Samantha Penny
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Dwarf Galaxies ◽  
Galactic Nuclei ◽  
Local Environment ◽  
Selection Method ◽  
Estimation Methods ◽  
Selection Methods ◽  
Low Mass ◽  
Future Work

ABSTRACT This study aims to explore the relation between dwarf galaxies (M* ≤ 5 × 109 M⊙) with active galactic nuclei (AGNs) and their environment by comparing neighbourhood parameters of AGN and non-AGN samples. Using the NASA-Sloan Atlas, both the local environment and the immediate environment of dwarf galaxies with z ≤ 0.055 are analysed. Of the 145 155 galaxies in the catalogue, 62 258 of them are classified as dwarf galaxies, and by employing two AGN selection methods based on emission-line fluxes (BPT and WHAN), 4476 are found to have AGN characteristics in their optical spectra. Regardless of selection method, this study finds no discernible differences in environment between AGN and non-AGN host dwarf galaxies and these results indicate that environment is not an important factor in triggering AGN activity in dwarf galaxies. This is in line with existing literature on environments of regular galaxies with AGNs and suggests universality in terms of reaction to environment across the mass regime. The biases of AGN selection in low-mass galaxies, and the biases of different measures of environment are also considered. It is found that there are several mass trends in emission-line ratios and that the SDSS fibre covers galaxies non-uniformly with redshift. These biases should be accounted for in future work by possibly including other wavelength regimes or mass weighting of emission-line ratios. Lastly, a discussion of the environment estimation methods is included since they may not gauge the desired properties due to factors such as time delay or using loosely constrained proxy parameters.

scholarly journals A self-lensing binary massive black hole interpretation of quasi-periodic eruptions

2021 ◽  
Vol 503 (2) ◽  
pp. 1703-1716
Author(s):  
Adam Ingram ◽  
Sara E Motta ◽  
Suzanne Aigrain ◽  
Aris Karastergiou
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Binary Systems ◽  
Galactic Nuclei ◽  
Galaxy Mergers ◽  
Massive Black Hole ◽  
X Ray ◽  
Binary Separation ◽  
Low Mass ◽  
Optical Time

ABSTRACT Binary supermassive black hole (SMBH) systems result from galaxy mergers, and will eventually coalesce due to gravitational wave (GW) emission if the binary separation can be reduced to ≲0.1 pc by other mechanisms. Here, we explore a gravitational self-lensing binary SMBH model for the sharp (duration ∼1 h), quasi-regular X-ray flares – dubbed quasi-periodic eruptions – recently observed from two low-mass active galactic nuclei: GSN 069 and RX J1301.9+2747. In our model, the binary is observed ∼edge-on, such that each SMBH gravitationally lenses light from the accretion disc surrounding the other SMBH twice per orbital period. The model can reproduce the flare spacings if the current eccentricity of RX J1301.9+2747 is ϵ0 ≳ 0.16, implying a merger within ∼1000 yr. However, we cannot reproduce the observed flare profiles with our current calculations. Model flares with the correct amplitude are ∼2/5 the observed duration, and model flares with the correct duration are ∼2/5 the observed amplitude. Our modelling yields three distinct behaviours of self-lensing binary systems that can be searched for in current and future X-ray and optical time-domain surveys: (i) periodic lensing flares, (ii) partial eclipses (caused by occultation of the background mini-disc by the foreground mini-disc), and (iii) partial eclipses with a very sharp in-eclipse lensing flare. Discovery of such features would constitute very strong evidence for the presence of a supermassive binary, and monitoring of the flare spacings will provide a measurement of periastron precession.

scholarly journals On the relationship between black hole mass and X-ray variability amplitude in the low-mass regime of active galactic nuclei

2014 ◽  
Vol 10 (S312) ◽  
pp. 73-74
Author(s):  
H. Pan ◽  
W. Yuan ◽  
X.-L. Zhou ◽  
X. Dong ◽  
B. Liu
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Power Spectrum Density ◽  
Black Hole Mass ◽  
X Ray ◽  
Spectrum Density ◽  
Simple Extrapolation ◽  
Low Mass ◽  
The Relationship

AbstractRecent studies of active galactic nuclei (AGN) found a statistical inverse scaling between the X-ray normalized excess variance σrms2 (variability amplitude) and the black hole mass spanning over MBH = 106 − 109M⊙. We present a study of this relation by including AGN with MBH = 105 − 106M⊙. It is found that the relation is no longer a simple extrapolation of the known inverse proportion, but starts to flatten around 106M⊙. This behavior can be understood by the shape of the power spectrum density of AGN and its dependence on the black hole mass.

scholarly journals Low-mass Active Galactic Nuclei on the Fundamental Plane of Black Hole Activity

2018 ◽  
Vol 860 (2) ◽  
pp. 134 ◽  
Author(s):  
Lei Qian ◽  
Xiao-Bo Dong ◽  
Fu-Guo Xie ◽  
Wenjuan Liu ◽  
Di Li
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Fundamental Plane ◽  
Low Mass

scholarly journals Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 279
Author(s):  
Zdeněk Stuchlík ◽  
Jaroslav Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Observational Data ◽  
High Frequency ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Periodic Oscillations ◽  
High Length ◽  
Circular Geodesic

We study epicyclic oscillatory motion along circular geodesics of the Simpson–Visser meta-geometry describing in a unique way regular black-bounce black holes and reflection-symmetric wormholes by using a length parameter l. We give the frequencies of the orbital and epicyclic motion in a Keplerian disc with inner edge at the innermost circular geodesic located above the black hole outer horizon or on the our side of the wormhole. We use these frequencies in the epicyclic resonance version of the so-called geodesic models of high-frequency quasi-periodic oscillations (HF QPOs) observed in microquasars and around supermassive black holes in active galactic nuclei to test the ability of this meta-geometry to improve the fitting of HF QPOs observational data from the surrounding of supermassive black holes. We demonstrate that this is really possible for wormholes with sufficiently high length parameter l.

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