scholarly journals A parsec-scale radio jet launched by the central intermediate-mass black hole in the dwarf galaxy SDSS J090613.77+561015.2

2020 ◽  
Vol 495 (1) ◽  
pp. L71-L75
Author(s):  
Jun Yang ◽  
Leonid I Gurvits ◽  
Zsolt Paragi ◽  
Sándor Frey ◽  
John E Conway ◽  
...  

ABSTRACT The population of intermediate-mass black holes (IMBHs) in nearby dwarf galaxies plays an important ‘ground truth’ role in exploring black hole formation and growth in the early Universe. In the dwarf elliptical galaxy SDSS J090613.77+561015.2 (z = 0.0465), an accreting IMBH has been revealed by optical and X-ray observations. Aiming to search for possible radio core and jet associated with the IMBH, we carried out very long baseline interferometry (VLBI) observations with the European VLBI Network at 1.66 GHz. Our imaging results show that there are two 1-mJy components with a separation of about 52 mas (projected distance 47 pc) and the more compact component is located within the 1σ error circle of the optical centroid from available Gaia astrometry. Based on their positions, elongated structures and relatively high brightness temperatures, as well as the absence of star-forming activity in the host galaxy, we argue that the radio morphology originates from the jet activity powered by the central IMBH. The existence of the large-scale jet implies that violent jet activity might occur in the early epochs of black hole growth and thus help to regulate the co-evolution of black holes and galaxies.

2019 ◽  
Vol 15 (S356) ◽  
pp. 376-376
Author(s):  
Ingyin Zaw

AbstractNuclear black holes in dwarf galaxies are important for understanding the low end of the supermassive black hole mass distribution and the black hole-host galaxy scaling relations. IC 750 is a rare system which hosts an AGN, found in ˜0.5% of dwarf galaxies, with circumnuclear 22 GHz water maser emission, found in ˜3–5% of Type 2 AGNs. Water masers, the only known tracer of warm, dense gas in the center parsec of AGNs resolvable in position and velocity, provide the most precise and accurate mass measurements of SMBHs outside the local group. We have mapped the maser emission in IC 750 and find that it traces a nearly edge-on warped disk, 0.2 pc in diameter. The central black hole has an upper limit mass of ˜1 × 105 M⊙ and a best fit mass of ˜8 × 104 M⊙, one to two orders of magnitude below what is expected from black hole-galaxy scaling relations. This has implications for models of black hole seed formation in the early universe, the growth of black holes, and their co-evolution with their host galaxies.


2020 ◽  
Vol 496 (4) ◽  
pp. 4061-4078 ◽  
Author(s):  
Timothy A Davis ◽  
Dieu D Nguyen ◽  
Anil C Seth ◽  
Jenny E Greene ◽  
Kristina Nyland ◽  
...  

ABSTRACT We estimate the mass of the intermediate-mass black hole at the heart of the dwarf elliptical galaxy NGC 404 using Atacama Large Millimetre/submillimetre Array (ALMA) observations of the molecular interstellar medium at an unprecedented linear resolution of ≈0.5 pc, in combination with existing stellar kinematic information. These ALMA observations reveal a central disc/torus of molecular gas clearly rotating around the black hole. This disc is surrounded by a morphologically and kinematically complex flocculent distribution of molecular clouds, that we resolve in detail. Continuum emission is detected from the central parts of NGC 404, likely arising from the Rayleigh–Jeans tail of emission from dust around the nucleus, and potentially from dusty massive star-forming clumps at discrete locations in the disc. Several dynamical measurements of the black hole mass in this system have been made in the past, but they do not agree. We show here that both the observed molecular gas and stellar kinematics independently require a ≈5 × 105 M⊙ black hole once we include the contribution of the molecular gas to the potential. Our best estimate comes from the high-resolution molecular gas kinematics, suggesting the black hole mass of this system is 5.5$^{+4.1}_{-3.8}\times 10^5$ M⊙ (at the 99 per cent confidence level), in good agreement with our revised stellar kinematic measurement and broadly consistent with extrapolations from the black hole mass–velocity dispersion and black hole mass–bulge mass relations. This highlights the need to accurately determine the mass and distribution of each dynamically important component around intermediate-mass black holes when attempting to estimate their masses.


2019 ◽  
Vol 489 (1) ◽  
pp. 1373-1378 ◽  
Author(s):  
Kastytis Zubovas ◽  
Andrew King

Abstract Active galactic nuclei (AGNs) probably control the growth of their host galaxies via feedback in the form of wide-angle wind-driven outflows. These establish the observed correlations between supermassive black hole (SMBH) masses and host galaxy properties, e.g. the spheroid velocity dispersion σ. In this paper we consider the growth of the SMBH once it starts driving a large-scale outflow through the galaxy. To clear the gas and ultimately terminate further growth of both the SMBH and the host galaxy, the black hole must continue to grow its mass significantly, by up to a factor of a few, after reaching this point. The mass increment ΔMBH depends sensitively on both galaxy size and SMBH spin. The galaxy size dependence leads to ΔMBH ∝ σ5 and a steepening of the M–σ relation beyond the analytically calculated M ∝ σ4, in agreement with observation. Slowly spinning black holes are much less efficient in producing feedback, so at any given σ the slowest spinning black holes should be the most massive. Current observational constraints are consistent with this picture, but insufficient to test it properly; however, this should change with upcoming surveys.


1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.


2020 ◽  
Vol 15 (S359) ◽  
pp. 238-242
Author(s):  
Mar Mezcua

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.


Author(s):  
Benjamin L. Davis ◽  
Alister W. Graham

Abstract Recent X-ray observations by Jiang et al. have identified an active galactic nucleus (AGN) in the bulgeless spiral galaxy NGC 3319, located just $14.3\pm 1.1$ Mpc away, and suggest the presence of an intermediate-mass black hole (IMBH; $10^2\leq M_\bullet/\textrm{M}_{\odot}\leq 10^5$ ) if the Eddington ratios are as high as 3 to $3\times10^{-3}$ . In an effort to refine the black hole mass for this (currently) rare class of object, we have explored multiple black hole mass scaling relations, such as those involving the (not previously used) velocity dispersion, logarithmic spiral arm pitch angle, total galaxy stellar mass, nuclear star cluster mass, rotational velocity, and colour of NGC 3319, to obtain 10 mass estimates, of differing accuracy. We have calculated a mass of $3.14_{-2.20}^{+7.02}\times10^4\,\textrm{M}_\odot$ , with a confidence of 84% that it is $\leq $ $10^5\,\textrm{M}_\odot$ , based on the combined probability density function from seven of these individual estimates. Our conservative approach excluded two black hole mass estimates (via the nuclear star cluster mass and the fundamental plane of black hole activity—which only applies to black holes with low accretion rates) that were upper limits of ${\sim}10^5\,{\textrm M}_{\odot}$ , and it did not use the $M_\bullet$ – $L_{\textrm 2-10\,\textrm{keV}}$ relation’s prediction of $\sim$ $10^5\,{\textrm M}_{\odot}$ . This target provides an exceptional opportunity to study an IMBH in AGN mode and advance our demographic knowledge of black holes. Furthermore, we introduce our novel method of meta-analysis as a beneficial technique for identifying new IMBH candidates by quantifying the probability that a galaxy possesses an IMBH.


2009 ◽  
Vol 5 (S267) ◽  
pp. 151-160 ◽  
Author(s):  
Bradley M. Peterson

AbstractWe review briefly direct and indirect methods of measuring the masses of black holes in galactic nuclei, and then focus attention on supermassive black holes in active nuclei, with special attention to results from reverberation mapping and their limitations. We find that the intrinsic scatter in the relationship between the AGN luminosity and the broad-line region size is very small, ~0.11 dex, comparable to the uncertainties in the better reverberation measurements. We also find that the relationship between reverberation-based black hole masses and host-galaxy bulge luminosities also seems to have surprisingly little intrinsic scatter, ~0.17 dex. We note, however, that there are still potential systematics that could affect the overall mass calibration at the level of a factor of a few.


2015 ◽  
Vol 12 (S316) ◽  
pp. 240-245
Author(s):  
Nora Lützgendorf ◽  
Markus Kissler-Patig ◽  
Karl Gebhardt ◽  
Holger Baumgardt ◽  
Diederik Kruijssen ◽  
...  

AbstractThe study of intermediate-mass black holes (IMBHs) is a young and promising field of research. If IMBH exist, they could explain the rapid growth of supermassive black holes by acting as seeds in the early stage of galaxy formation. Formed by runaway collisions of massive stars in young and dense stellar clusters, intermediate-mass black holes could still be present in the centers of globular clusters, today. We measured the inner kinematic profiles with integral-field spectroscopy for 10 Galactic globular cluster and determined masses or upper limits of central black holes. In combination with literature data we further studied the positions of our results on known black-hole scaling relations (such as M• − σ) and found a similar but flatter correlation for IMBHs. Applying cluster evolution codes, the change in the slope could be explained with the stellar mass loss occurring in clusters in a tidal field over its life time. Furthermore, we present results from several numerical simulations on the topic of IMBHs and integral field units (IFUs). N-body simulations were used to simulate IFU data cubes. For the specific case of NGC 6388 we simulated two different IFU techniques and found that velocity dispersion measurements from individual velocities are strongly biased towards lower values due to blends of neighbouring stars and background light. In addition, we use the Astrophysical Multipurpose Software Environment (AMUSE) to combine gravitational physics, stellar evolution and hydrodynamics to simulate the accretion of stellar winds onto a black hole. We find that the S-stars need to provide very strong winds in order to explain the accretion rate in the galactic center.


2009 ◽  
Vol 5 (S267) ◽  
pp. 273-282
Author(s):  
Andrew King

AbstractI review accretion and outflow in active galactic nuclei. Accreti4on appears to occur in a series of very small-scale, chaotic events, whose gas flows have no correlation with the large-scale structure of the galaxy or with each other. The accreting gas has extremely low specific angular momentum and probably represents only a small fraction of the gas involved in a galaxy merger, which may be the underlying driver.Eddington accretion episodes in AGN must be common in order for the supermassive black holes to grow. I show that they produce winds with velocities v ~ 0.1c and ionization parameters implying the presence of resonance lines of helium-like and hydrogen-like iron. The wind creates a strong cooling shock as it interacts with the interstellar medium of the host galaxy, and this cooling region may be observable in an inverse Compton continuum and lower-excitation emission lines associated with lower velocities. The shell of matter swept up by the shocked wind stalls unless the black hole mass has reached the value Mσ implied by the M–σ relation. Once this mass is reached, further black hole growth is prevented. If the shocked gas did not cool as asserted above, the resulting (“energy-driven”) outflow would imply a far smaller SMBH mass than actually observed. Minor accretion events with small gas fractions can produce galaxy-wide outflows, including fossil outflows in galaxies where there is little current AGN activity.


2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
David Garofalo

While the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. Because astrophysics deals with the largest structures in the Universe, one expects evidence there for the most pronounced entropic arrow of time. However, in recent theoretical astrophysics work it appears possible to identify constructs with time-reversal symmetry, which is puzzling in the large-scale realm especially because it involves the engines of powerful outflows in active galactic nuclei which deal with macroscopic constituents such as accretion disks, magnetic fields, and black holes. Nonetheless, the underlying theoretical structure from which this accreting black hole framework emerges displays a time-symmetric harmonic behavior, a feature reminiscent of basic and simple laws of physics. While we may expect such behavior for classical black holes due to their simplicity, manifestations of such symmetry on the scale of galaxies, instead, surprise. In fact, we identify a parallel between the astrophysical tug-of-war between accretion disks and jets in this model and the time symmetry-breaking of a simple overdamped harmonic oscillator. The validity of these theoretical ideas in combination with this unexpected parallel suggests that black holes are more influential in astrophysics than currently recognized and that black hole astrophysics is a more fundamental discipline.


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