192 research outputs found
General Physical Properties of Gamma-Ray-emitting Radio Galaxies
We study the radio galaxies with known redshift detected by the Fermi
satellite after 10 years of data (4FGL-DR2). We use a one-zone leptonic model
to fit the quasi-simultaneous multiwavelength data of these radio galaxies and
study the distributions of the derived physical parameter as a function of
black hole mass and accretion disk luminosity. The main results are as follows.
(1) We find that the jet kinetic power of most radio galaxies can be explained
by the hybrid jet model based on ADAFs surrounding Kerr black holes. (2) After
excluding the redshift, there is a significant correlation between the
radiation jet power and the accretion disk luminosity, while the jet kinetic
power is weakly correlated with the accretion disk luminosity. (3) We also find
a significant correlation between inverse Compton luminosity and synchrotron
luminosity. The slope of the correlation for radio galaxies is consistent with
the synchrotron self-Compton (SSC) process. The result may suggest that the
high-energy component of radio galaxies is dominated by the SSC process.Comment: 9 pages,7 figures, accept for publication in ApJ
The jet formation mechanism of Gamma-ray Narrow-line Seyfert 1 Galaxies
Under the coronal magnetic field, we estimate the maximal jet power of the
Blandford-\Znajek (BZ) mechanism, Blandford-\Payne (BP) mechanism, and hybrid
model. The jet power of the BZ and Hybrid model mechanisms depends on the spin
of a black hole, while the jet power of the BP mechanism does not depend on the
spin of a black hole. At high black hole spin, the jet power of the hybrid
model is greater than that of the BZ and BP mechanisms. We find that the jet
power of almost all gamma-\ray narrow line Seyfert 1 galaxies (gamma-\NLS1s)
can be explained by the hybrid model. However, one source with jet power 0.1~\1
Eddington luminosity can not be explained by the hybrid model. We suggest that
the magnetic field dragged inward by the accretion disk with
magnetization-\driven outflows may accelerate the jets in this gamma-\NLS1.Comment: 9 pages,6 figures,accepted for publication in MNRA
Sub-percentage measure of distances to redshift of 0.1 by a new cosmic ruler
Distance-redshift diagrams probe expansion history of the Universe. We show
that the stellar mass-binding energy (massE) relation of galaxies proposed in
our previous study offers a new distance ruler at cosmic scales. By using
elliptical galaxies in the main galaxy sample of the Sloan Digital Sky Survey
Data Release 7, we construct a distance-redshift diagram over the redshift
range from 0.05 to 0.2 with the massE ruler. The best-fit dark energy density
is 0.675+-0.079 for flat Lambda-CDM, consistent with those by other probes. At
the median redshift of 0.11, the median distance is estimated to have a
fractional error of 0.34%, much lower than those by supernova (SN) Ia and
baryonic acoustic oscillation (BAO) and even exceeding their future capability
at this redshift. The above low-z measurement is useful for probing dark energy
that dominates at the late Universe. For a flat dark energy equation of state
model (flat wCDM), the massE alone constrains w to an error that is only a
factor of 2.2, 1.7 and 1.3 times larger than those by BAO, SN Ia, and cosmic
microwave background (CMB), respectively.Comment: 8 pages, 5 figures, MNRAS in press. The cosmoSIS modules for the
massE ruler is at
https://astronomy.nju.edu.cn/DFS//file/2022/07/02/20220702161632756vbde28.zi
An Escaping Outflow in a Galaxy with an Intermediate-mass Black Hole
While in massive galaxies active galactic nuclei (AGN) feedback plays an
important role, the role of AGN feedback is still under debate in dwarf
galaxies. With well spatially resolved data obtained from the Multi-Unit
Spectroscopic Explorer (MUSE), we identify a spatially extended () and fast () AGN-driven outflow in a
dwarf galaxy: SDSS J022849.51-090153.8 with that host an intermediate-mass black hole of and . Through the
measurement of the rotation curve, we estimate the escape velocity of the halo
and the ratio of the outflow velocity to the halo escape velocity to be
, indicating that the outflow is capable of escaping not only the
galaxy disk but the halo. The outflow size of our AGN is found to be larger
than AGN in massive galaxies at the given AGN [O III] luminosity, while the
size of the photo-ionized narrow-line region is comparable. These results
suggest the important role of AGN feedback through outflows in dwarf galaxies
when their central intermediate-mass black holes accrete at high-Eddington
ratios.Comment: 12 pages, 2 tables, 12 figures, accepted for publication in MNRA
Multiwavelength Analysis of a Nearby Heavily Obscured AGN in NGC 449
We presented the multiwavelength analysis of a heavily obscured active
galactic nucleus (AGN) in NGC 449. We first constructed a broadband X-ray
spectrum using the latest NuSTAR and XMM-Newton data. Its column density
() and photon index () were
reliably obtained by analyzing the broadband X-ray spectrum. However, the
scattering fraction and the intrinsic X-ray luminosity could not be well
constrained. Combined with the information obtained from the mid-infrared
(mid-IR) spectrum and spectral energy distribution (SED) fitting, we derived
its intrinsic X-ray luminosity ()
and scattering fraction (). In addition, we also
derived the following results: (1). The mass accretion rate of central AGN is
about , and the Eddington ratio
is ; (2). The torus of this AGN has a high gas-to-dust
ratio ();
(3). The host galaxy and the central AGN are both in the early stage of
co-evolution.Comment: 12 pages, 5 figures, 3 tables, Accepted to PAS
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