192 research outputs found

    General Physical Properties of Gamma-Ray-emitting Radio Galaxies

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    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

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    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

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    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

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    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 (∼3β€…β€Škpc\rm \sim 3\; kpc) and fast (V80∼471β€…β€Škmβ€…β€Šsβˆ’1V_{80} \sim 471\; \rm km\;s^{-1}) AGN-driven outflow in a dwarf galaxy: SDSS J022849.51-090153.8 with Mβˆ—βˆΌ109.6β€…β€ŠMβŠ™M_{*} \sim 10^{9.6}\;{\rm M_{\odot}} that host an intermediate-mass black hole of MBH∼105β€…β€ŠMβŠ™M_{\rm BH} \sim 10^5\;{\rm M_{\odot}} and LAGN/LEdd∼0.15L_{\rm AGN}/L_{\rm Edd} \sim 0.15. 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 1.09Β±0.041.09\pm0.04, 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

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    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 (≃1024cmβˆ’2\simeq 10^{24} \rm{cm}^{-2}) and photon index (Γ≃2.4\Gamma\simeq 2.4) 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 (≃8.54Γ—1042Β ergΒ sβˆ’1\simeq 8.54\times 10^{42} \ \rm{erg\ s}^{-1}) and scattering fraction (fscat≃0.26%f_{\rm{scat}}\simeq 0.26\%). In addition, we also derived the following results: (1). The mass accretion rate of central AGN is about 2.54Γ—10βˆ’2MβŠ™Β yrβˆ’12.54 \times 10^{-2} \rm{M}_\odot\ \rm{yr}^{-1}, and the Eddington ratio is 8.39Γ—10βˆ’28.39\times 10^{-2}; (2). The torus of this AGN has a high gas-to-dust ratio (NH/AV=8.40Γ—1022Β cmβˆ’2Β magβˆ’1N_{\rm H}/A_{\rm V}=8.40\times 10^{22}\ \rm{cm}^{-2}\ \rm{mag}^{-1}); (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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