arXiv subjects

Hongyan Zhou

Publications and source records attributed to Hongyan Zhou.

At least 19 recordsLinked to original sources

arXiv2026

A superflare of BP Tau simultaneously caught by EP X-ray and TESS optical observations

Multiwavelength observations of stellar flares trace the activity of different components of the stars' outer atmosphere, providing insight into their interactions. In the present paper, we report a superflare from BP Tau, simultaneously observed with the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) satellite and TESS. While we attribute the X-ray flux increase to a magnetically powered flare, the optical light curve likely results from the superposition of the flare and an accretion burst. The X-ray flare has a mean flux of $(1.5^{+0.3}_{-0.4})\times10^{-11}$ erg cm$^{-2}$ s$^{-1}$ in the WXT energy band (0.5-4.0 keV), with e-folding times of $1.7\pm1.0$ ks and $14\pm5$ ks for the rise and decay phase, respectively. The corresponding time-integrated flare energy is $(1.0\pm 0.2)\times 10^{36}$ erg. The optical flare has an e-folding time of $0.33\pm0.04$ ks for the rise phase, but the data do not constrain the decay timescale. Assuming a decay phase equal to the rise phase, the resulting optical flare energy is $(2.8\pm0.4)\times10^{34}$ erg in the TESS band ($\sim6,000$-$\sim10,000$ \AA), corresponding to a bolometric energy of $(1.9\pm0.3)\times10^{35}$ erg (assuming a blackbody at 11000 K). The Follow-up X-ray Telescope (FXT) on EP triggered an observation $\sim1.5$ day after the flare, with a flux of $(4.6^{+0.2}_{-0.5})\times10^{-13}$ erg cm$^{-2}$ s$^{-1}$ (0.5-10.0 keV), indicating that BP Tau had returned to quiescence. This work demonstrates the potential of jointly analyzing EP and TESS data for superflares. WXT is expected to detect $\sim800$ superflares per year, with FXT capable of slewing to the flaring star within $\sim3$-5 minutes. The large field of view of both missions offers us the opportunity to study multiwavelength variability during energetic flares.

astro-ph.SR↗

arXiv2026

Sharp Broken-Power Lorentz Estimates for Fractional Powers of Radial Schr\"odinger Operators with Inverse-Square Asymptotics

Let $H=-\Delta+V(|x|)$ be a nonnegative radial Schr\"odinger operator on $\mathbb{R}^d$, $d\ge 2$, whose positive harmonic function satisfies $U(r)\simeq r^{-\sigma_0}$ for $0<r\le 1$ and $U(r)\simeq r^{-\sigma_\infty}$ for $r\ge 1$, with $-d/2<\sigma_0,\sigma_\infty<d/2$. Assuming the two-sided ground-state heat-kernel estimate of Ishige, Kabeya, and Ouhabaz, we determine the maximal open range in which the kernel of $H^{-s/2}$ admits the clean two-sided estimate $K_s^H(x,y)\simeq |x-y|^{s-d}U(|x|)U(|y|)/[U(|x|+|x-y|)U(|y|+|x-y|)]$, namely $0<s<\min\{d,d-2\sigma_0,d-2\sigma_\infty\}$. In this range we give a complete necessary-and-sufficient classification of the broken-power estimate $\|w_{-\beta_0,-\beta_\infty}H^{-s/2}f\|_{L^{q,v}}\lesssim \|w_{\alpha_0,\alpha_\infty}f\|_{L^{p,u}}$ for $1<p,q<\infty$ and $1\le u,v\le\infty$. The result covers signed ground-state exponents, the full range $q<p$, all one-sided weight equalities, both scale equalities, and simultaneous endpoint corners. Scale equality is governed by $u\le v$, including when $q<p$; an input or output power endpoint requires respectively $u=1$ or $v=\infty$; and at a same-side power/scale corner the only admissible pair is $(u,v)=(1,\infty)$. The proof combines clean-kernel analysis, local Lorentz-Hardy-Littlewood-Sobolev estimates, rank-one endpoint arguments, geometric annular sequence spaces, a triangular matrix theorem, and a nine-block decomposition.

math.AP↗

arXiv2026

Sharp and Endpoint Two-Weight Fractional Integral Estimates for Schr"odinger Operators with Inverse-Square Potentials

Let $H_a=-\Delta+a|x|^{-2}$ be the Friedrichs extension on $L^2(\mathbb{R}^d)$, where $d\ge 3$ and $-(d-2)^2/4\le a<0$ lies in the attractive Hardy range. Starting from the known positive two-sided comparison for the kernel of $H_a^{-s/2}$, we determine the complete strong non-endpoint mapping range for two power weights. If $\sigma=(d-2-\sqrt{(d-2)^2+4a})/2$ and $0<s<d-2\sigma$, then [ ||x|^{-\beta}H_a^{-s/2}f|{L^q} \lesssim ||x|^\alpha f|{L^p} ] holds for $1<p,q<\infty$ precisely under the exponent ordering, scaling, sum, and origin conditions stated in the main theorem. At either origin-critical boundary, the strong estimate and the corresponding weighted $L^p\to L^{q,\infty}$ estimate fail, whereas the Lorentz replacement $L^{p,1}\to L^{q,\infty}$ holds. We also derive weighted Sobolev consequences and treat the Hardy-critical Friedrichs case separately. No new heat-kernel, spectral multiplier, Bernstein, or Littlewood--Paley theorem is claimed.

math.CA↗

arXiv2025

A fast powerful X-ray transient from possible tidal disruption of a white dwarf

Stars captured by black holes (BHs) can be torn apart by strong tidal forces, producing electromagnetic flares. To date, more than 100 tidal disruption events (TDEs) have been observed, each involving invariably normal gaseous stars whose debris falls onto the BH, sustaining the flares over years. White dwarfs (WDs), which are the most prevalent compact stars and a million times denser--and therefore tougher--than gaseous stars, can only be disrupted by intermediate-mass black holes (IMBHs) of 10^2--10^5 solar masses. WD-TDEs are considered to generate more powerful and short-lived flares, but their evidence has been lacking. Here we report observations of a fast and luminous X-ray transient EP250702a detected by Einstein Probe. Its one-day-long X-ray peak as luminous as 10^(47-49) erg/s showed strong recurrent flares with hard spectra extending to several tens of MeV gamma-rays, as detected by Fermi/GBM and Konus-Wind, indicating relativistic jet emission. The jet's X-ray dropped sharply from 3 x 10^49 erg/s to around 10^44 erg/s within 20 days (10 days in the source rest frame). These characteristics are inconsistent with any known transient phenomena other than a jetted-TDE evolving over an unprecedentedly short timescale, indicating the disruption of a WD by an IMBH. At late times, a new soft component progressively dominates the X-ray spectrum, exhibiting an extreme super-Eddington luminosity, which possibly originates from an accretion disc. WD-TDEs open a new window for investigating the elusive IMBHs and their surrounding stellar environments, and they are prime sources of gravitational waves in the band of space-based interferometers.

astro-ph.HE↗

arXiv2024

Metal-strong Inflows at the Outer-galactic-scale of a Quasar

We present an analysis of the absorption-line system in the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph spectrum at a redshift of $z_{\rm a}={3.1448}$ associated with the quasar SDSS J122040.23+092326.96, whose systematic redshift is $z_{\rm e}=3.1380\pm0.0007$, measured from the ${\rm H}\beta$+[O III] emission lines in our newly acquired NIR P200/TripleSpec data. This absorbing system, detected in numerous absorption lines including the N V, N III, C IV, C III, Si IV, Si III, and H I Lyman series, can be resolved into seven kinematic components with red-shifted velocities ranging from 200 to $900\,\rm km\,s^{-1}$. The high-ionization N V doublet detected and the rather narrow Lyman series measured ($b\approx14\,\rm km\,s^{-1}$) suggest that the absorption gas is photo ionized, possibly by the quasar. A low density is inferred by the fact that N III $\lambda989.80$ is significantly detected while N III* $\lambda991.51$ (${\rm log}\,n_{\rm c}=3.3\,\rm cm^{-3}$) is undetectably weak. A firm lower limit of a solar value to the abundance of the gas can be set based on the measurements of Si IV and H I column densities, as first proposed by F. Hamann. Detailed photoionization simulations indicate that $T1$, and possibly the absorber as a whole, has metallicities of $Z\sim1.5-6.0\,Z\rm\,sun$, and is located at $\sim15\,\rm kpc$ from the quasar nucleus. The metal-strong absorption inflows at the outskirt of the quasar host galaxy is most likely originated in situ and were driven by stellar processes, such as stellar winds and/or supernova explosions. Such a relatively rare system may hold important clues to understanding the baryonic cycling of galaxies, and more cases could be picked out using relatively strong Si IV and weak Lyman absorption lines.

astro-ph.GA↗

arXiv2024

Discovery of a Damped Ly$α$ Absorber in the Circumnuclear Zone of the FeLoBAL Quasar SDSS J083942.11+380526.3

SDSS J083942.11+380526.3 ($z=2.315$) is a FeLoBAL quasar that exhibits visible Balmer absorption lines (H$α$), implying a significant $n=2$ population. The quasar also shows an array of absorption lines, including \oi, \niii, \feii, \mgii, \aliii\, to \civ\ and \nv. The high-ionization absorption lines such as \civ\ and \siiv\ are revealed by slightly blueshifted BAL troughs. The resonance doublets such as \mgii\ and \aliii\ are saturated but did not reached zero intensity which indicates that the BLR is partially covered. Overall, however, the absorption is predominantly from low-ionization \feii\ lines, emitted from ground and excited states up to at least 3.814 eV. This implies that the absorbing gas spans the hydrogen ionization front and extends into the partially ionized zone where neutral hydrogen is certainly present. Notably, the hydrogen line spectrum of the quasar shows no signature of expected Ly$α$ absorption. Instead, the line spectrum shows an unusual Ly$α$ emission characterized by a fully filled emission line spectrum which is a composite of a strong narrow core superposed on a weak broad base. Taking into account the effect of partial covering to BLR, we have extracted a strong DLA trough in Ly$α$ emission region. To fit the spectrum, we performed photoionized model calculations and compared them to the observations. We found that photoionization modeling using CLOUDY can successfully reproduce the main characteristics of the quasar spectrum, and the predicted neutral hydrogen column density arising from the clouds responsible for the low-ionization absorption provides a good match to the extracted DLA trough. This indicates that both the DLA and the low-ionization absorption arise from the same medium that is roughly collocated with the dusty torus.

astro-ph.GA↗

arXiv2024

A comparative study of ultraluminous infrared galaxies in the IRAS and SDSS Surveys

We present a comprehensive study of Ultraluminous Infrared Galaxies (ULIRGs), leveraging data from the IRAS Faint Source Catalogue (FSC) and the spectroscopic catalog in the Sloan Digital Sky Survey (SDSS) DR16. Our meticulous cross-matching technique significantly enhances the reliability of ULIRG identification, resulting in the identification of 283 reliable ULIRGs, including 102 new detections, while discarding 120 previously reported false sources. Covering a redshift range of $z = 0.018 - 0.996$, with a median redshift of $\bar{z} = 0.259$, our uniform sample reveals apparent interaction features in approximately 40\% of ULIRGs, increasing to 92\% for those with $z < 0.1$. Through optical spectra analysis, it is indicated that over 58\% of ULIRGs host an AGN, which is twice as high as the detections based solely on infrared colors. Moreover, a pronounced excess of radio emissions associated with AGN activity results in a steeper radio-far-infrared correlation. Notably, Type I ULIRGs exhibit properties similar to those of narrow-line Seyfert 1 galaxies (NLS1s), with an elevated incidence rate of \ion{Mg}{2} BALs (16.7\%), surpassing that of typical optically selected quasars by over tenfold, consistent with current evolutionary models. We anticipate that forthcoming telescopes such as the China Space Station Telescope (CSST) and Leighton Chajnantor Telescope (LCT) will provide deeper insights into ULIRG morphology, dust distribution, molecular gas, and AGN activity.

astro-ph.GA↗

arXiv2023

Time Variation of Fine-Structure Constant Constrained by [O III] Emission-Lines at 1.1<z<3.7

[O III]$λλ$4960,5008 doublet are often the strongest narrow emission lines in starburst galaxies and quasi-stellar objects (QSOs), and thus are a promising probe to possible variation of the fine-structure constant $α$ over cosmic time. Previous such studies using QSOs optical spectra were limited to $z<1$. In this work, we constructed a sample of 40 spectra of Ly$α$ emitting galaxies (LAEs) and a sample of 46 spectra of QSOs at $1.09<z<3.73$ using the VLT/X-Shooter near-infrared spectra publicly available. We measured the wavelength ratios of the two components of the spin-orbit doublet and accordingly calculated $α(z)$ using two methods. Analysis on all of the 86 spectra yielded $Δα/α=(-3\pm6)\times10^{-5}$ with respect to the laboratory $α$ measurements, consistent with no variation over the explored time interval. If assuming a uniform variation rate, we obtained $α^{-1}{\rm d}α/{\rm d}t = (-3\pm6)\times10^{-15}$ yr$^{-1}$ within the last 12 Gyrs. Extensive tests indicate that $α$ variation could be better constrained using starburst galaxies' spectra than using QSO spectra in future studies.

astro-ph.GA↗

arXiv2023

Improving Robustness of Deep Convolutional Neural Networks via Multiresolution Learning

The current learning process of deep learning, regardless of any deep neural network (DNN) architecture and/or learning algorithm used, is essentially a single resolution training. We explore multiresolution learning and show that multiresolution learning can significantly improve robustness of DNN models for both 1D signal and 2D signal (image) prediction problems. We demonstrate this improvement in terms of both noise and adversarial robustness as well as with small training dataset size. Our results also suggest that it may not be necessary to trade standard accuracy for robustness with multiresolution learning, which is, interestingly, contrary to the observation obtained from the traditional single resolution learning setting.

cs.LG↗

arXiv2022

Optical flux and spectral variability of BL Lacertae during its historical high outburst in 2020

BL Lacertae had undergone a series of historical high flux activity over a year, from August 2020 in the optical to VHE $γ$-rays. In this paper, we report on optical flux and spectral variability of the first historical maxima outburst event during October-November in g, r and i bands with the 1.26m telescope at Xinglong observatory, China. We detected significant intranight variations with amplitude rising up to $\sim 30$%, when the fastest variability timescale is found to be a few tens of minutes, giving an emitting region size of the order $10^{-3}$ pc, which corresponds to $\sim 100$ Schwarzschild radius of the central black hole, likely coming from some jet mini-structures. Unlike on intranight timescale, a clear frequency dependent pattern along with symmetric timescales ($\sim$ 11d) of flux variation are detected on long timescale. The spectral evolution was predominated by flattening of the spectra with increasing brightness i.e., a bluer-when-brighter trend in 96% of the cases. On the night before the outburst peak, the color indices clustered in two distinct branches in color--magnitude diagram within a period of $\sim$ 6 hours that is connected to a hard-soft-hard spectral evolution trend extracted from time-resolved spectra. Such trend has never seen in BL Lac or any other blazars before to the best of our knowledge. The results obtained in this study can be explained in the context of shock induced particle acceleration or magnetic re-connection in the jet where turbulent processes most likely resulted the asymmetric flux variation on nightly timescale.

astro-ph.HE↗

arXiv2022

Compact and variable radio emission from an active galaxy with supersoft X-ray emission

RX J1301.9+2747 is a unique active galaxy with supersoft X-ray spectrum that lacks significant emission at energies above 2 keV. In addition, it is one of few galaxies displaying quasi-periodic X-ray eruptions that recur on a timescale of 13-20 ks. We present multi-epoch radio observations of RX J1301.9+2747 using GMRT, VLA and VLBA. The VLBA imaging at 1.6 GHz reveals a compact radio emission unresolved at a scale of <0.7 pc, with a brightness temperature of T_b>5x10^7 K. The radio emission is variable by more than a factor of 2.5 over a few days, based on the data taken from VLA monitoring campaigns. The short-term radio variability suggests that the radio emitting region has a size as small as 8x10^{-4} pc, resulting in an even higher brightness temperature of T_b ~10^{12} K. A similar limit on the source size can be obtained if the observed flux variability is not intrinsic and caused by the interstellar scintillation effect. The overall radio spectrum is steep with a time-averaged spectral index alpha=-0.78+/-0.03 between 0.89 GHz and 14 GHz. These observational properties rule out a thermal or star-formation origin of the radio emission, and appear to be consistent with the scenario of episodic jet ejections driven by magnetohydrodynamic process. Simultaneous radio and X-ray monitoring observations down to a cadence of hours are required to test whether the compact and variable radio emission is correlated with the quasi-periodic X-ray eruptions.

astro-ph.GA↗

arXiv2022

Broad Emission and Absorption Line Outflows in the Quasar SDSS J163345.22+512748.4

We present a detailed study of the optical and NIR emission and absorption line spectrum of the quasar SDSS J163345.22+512748.4. We discovered on the newly acquired NIR spectrum a highly meta-stable neutral helium broad absorption line (BAL) \heiozetz\ with a width of $\sim$ 2000 \kmps\ and a blueshift of $\sim$ 7000 \kmps\ in the velocity space. The BAL system is also significantly detected in \mgii\ and \heiteen. We estimate a column density of $(5.0 \pm 1.7) \times 10^{14}$ cm$^{-2}$ for the HeI*(2~$^3$S) level, and infer an ionization parameter of $U_{A} = 10^{-1.9\pm 0.2}$ for the BAL outflow assuming that the BAL region is thick enough for a full development of an ionization front. The total column density of the BAL outflow is constrained in the range N$\rm _{H}$ $\sim$ 10$^{21}$-10$^{21.4}$ cm$^{-2}$. We also found that the bulk of both MgII and UV FeII, as well as H$α$ broad emission lines (BELs) are blueshifted with a velocity of $\sim$ 2200 \kmps\ with respect to the quasar systemic redshift. We constrain that the blueshifted BEL region has a covering factor $C_{f}\approx 16\%$, a density n$\rm _{H}$ $\sim $ 10$^{10.6}$-10$^{11.3}$ cm$^{-3}$, a column density N$\rm _{H}\gtrsim 10^{23}$ cm$^{-2}$, and an ionization parameter $U_{E}\sim 10^{-2.1}-10^{-1.5}$. The outflow gas is located at $\sim$0.1 pc away from the central ionization source, at a scale comparable to the BLR. A toy kinetic model has been proposed to reproduce the profile of MgII BEL well if assuming a partial obscured axisymmetric geometry of the outflow with a radial velocity as observed by the BALs.

astro-ph.GA↗

arXiv2022

The 2175 Å~ Bump Features in FeLoBAL Quasars: One Indicator of MW-like Dust in the Nuclear Region of Quasar

To investigate the properties of dust in the nuclear region of quasars, we explored the extinction curves of the iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J163004.29+311957.6 and its two analogues. The parameterized extinction curves indicated the Milky Way-like 2175 Å~ bump features in underlying extinction, which are similar to those seen in the Local Group and a subset of high-redshift star-forming galaxies. Compared to the bump features in the Large Magellanic Clouds (LMC), the detections in this work are much closer to those in the Milky Way (MW). These bump features, as well as those in the high- and low-ionization broad absorption line (BAL) quasars of Zhang et al., are probably the counterpart of the 2175 Å~ bump features in the quasar environment. This type of dust grain is generally small, easily disrupted by high-energy photons and has difficulty surviving in the radiation field of the active galactic nucleus (AGN). However, due to the presence of absorption-line outflows, the 2175 Å~ bump feature in quasars, which should be rare, is seen many times in BAL quasars. The shielding effect of outflow clouds allows the MW-like dust grains to be assembled or extends the survival period in the quasar nuclear region. The process, and physical and chemical conditions deserve further observational study and investigation.

astro-ph.GA↗

arXiv2022

Feeding the Accretion Disk from the Dusty Torus in a Reddened Quasar

We present here a detailed analysis of an unusual absorption line system in the quasar SDSS J122826.79+100532.2. The absorption lines in the system have a common redshifted velocity structure starting from $v\sim0$ and extending to $\sim1,000\ \mathrm{km~s}^{-1}$, and are clearly detected in hydrogen Balmer series up to H$ι$, in metastable neutral helium triplet, and in optical lines of excited states of single ionized iron. We estimated that the absorber has a density $n_{\mathrm{H}}\approx10^{8.4}\ \mathrm{cm}^{-3}$ and an ionization parameter $U\approx10^{-1.2}$, thereupon located it at $r_{\mathrm{abs}}\approx1.5$ pc from the central supermassive black hole. The inferred distance is remarkably similar to the evaporation radius for dust grains $r_{\mathrm{evap}}\approx1$ pc in the quasar. Thus the absorber may be a probe of an inflow starting from the dusty torus and feeding the accretion disk. Both the featureless continuum and the broad emission lines are heavily reddened with $E(B-V)\approx0.66$, in contrast to the narrow emission lines whose reddening is negligible. The dusty medium could be located in between the broad and narrow emission line regions, and possibly be associated with a 'cold' narrow absorption line system detected in \ion{Ca}{2} and \ion{Na}{1} doublets nearly unshifted from the quasar systemic velocity. SDSS J122826.79+100532.2 might represent such a rare case that both the inflow and the torus could be tracked by absorption lines.

astro-ph.GA↗

arXiv2021

Monolithic Integrated Multiband Acoustic Devices on Heterogeneous Substrate for Sub-6 GHz RF-FEMs

Monolithic integration of multiband (1.4~ 6.0 GHz) RF acoustic devices were successfully demonstrated within the same process flow by using the lithium niobate (LN) thin film on silicon carbide (LNOSiC) substrate. A novel surface mode with sinking energy distribution was proposed, exhibiting reduced propagation loss. Surface wave and Lamb wave resonators with suppressed transverse modes and leaky modes were demonstrated, showing scalable resonances from 1.4 to 5.7 GHz, electromechanical coupling coefficients (k2) between 7.9% and 29.3%, and maximum Bode-Q (Qmax) larger than 3200. Arrayed filters with a small footprint (4.0 x 2.5 mm2) but diverse center frequencies (fc) and 3-dB fractional bandwidths (FBW) were achieved, showing fc from 1.4 to 6.0 GHz, FBW between 3.3% and 13.3%, and insertion loss (IL) between 0.59 and 2.10 dB. These results may promote the progress of hundred-filter sub-6 GHz RF front-end modules (RF-FEMs).

eess.SP↗

arXiv2021

B2 0003+38A: a classical flat-spectrum radio quasar hosted by a rotation-dominated galaxy with a peculiar massive outflow

We present a detailed analysis of the single-slit optical spectrum of the Flat-Spectrum Radio Quasar (FSRQ) B2 0003+38A, taken by the Echellette Spectrograph and Imager (ESI) on the Keck II telescope. This classical low-redshift FSRQ ($z=0.22911$, as measured from the stellar absorption lines) remains underexplored in its emission lines, though its broad-band continuum properties from radio to X-ray is well-studied. After removing the unresolved quasar nucleus and the starlight from the host galaxy, we obtain a spatially-resolved 2-D spectrum, which clearly shows three components, indicating a rotating disk, an extended emission line region (EELR) and an outflow. The bulk of the EELR, with a characteristic mass $M_{\rm EELR}\sim 10^{7}~\rm M_{\odot}$, and redshifted by $v_{\rm EELR}\approx 120$ km s$^{-1}$ with respect to the quasar systemic velocity, shows a one-sided structure stretching to a projected distance of $r_{\rm EELR}\sim 20$ kpc from the nucleus. The rotation curve of the rotating disk is well consistent with that of a typical galactic disk, suggesting that the FSRQ is hosted by a disk galaxy. This conclusion is in accordance with the facts that strong absorption in the HI 21-cm line was previously observed, and that Na I$λ\lambda5891,5897$ and Ca II$λ\lambda3934,3969$ doublets are detected in the optical ESI spectrum. B2 0003+38A will become the first FSRQ discovered to be hosted by a gas-rich disk galaxy, if this is confirmed by follow-up deep imaging and/or IFU mapping with high spatial resolution. These observations will also help unravel the origin of the EELR.

astro-ph.GA↗

arXiv2021

Mrk 1239: a Type-2 Counterpart of Narrow-line Seyfert-1?

We present new spectrophotometric and spectropolarimetric observations of Mrk 1239, one of the 8 prototypes that defines type-1 narrow-line Seyfert galaxies (NLS1s). Unlike the other typical NLS1s though, a high degree of polarization ($P\sim$5.6%) and red optical-IR ($g-W_4$ = 12.35) colors suggest that Mrk 1239 is more similar to type-2 active galactic nuclei like NGC 1068. Detailed analysis of spectral energy distribution in the UV-optical-IR yields two components from the nucleus: a direct and transmitted component that is heavily obscured ($E_{B-V} \approx 1.6$), and another indirect and scattered one with mild extinction ($E_{B-V} \sim$ 0.5). Such a two-light-paths scenario is also found in previous reports based on the X-ray data. Comparison of emission lines and the detection of He\,{\footnotesize I}*$λ$10830 BAL at [-3000,-1000] km s$^{-1}$ indicates that the obscuring clouds are at physical scale between the sublimation radius and that of the narrow emission line regions. The potential existence of powerful outflows is found as both the obscurer and scatterer are outflowing. Similar to many other type-2s, jet-like structure in the radio band is found in Mrk 1239, perpendicular to the polarization angle, suggesting polar scattering. We argue that Mrk 1239 is very probably a type-2 counterpart of NLS1s. The identification of 1 out of 8 prototype NLS1s as a type-2 counterpart implies that there can be a substantial amount of analogs of Mrk 1239 misidentified as type-1s in the optical band. Properties of these misidentified objects are going to be explored in our future works.

astro-ph.GA↗

arXiv2021

The Powers of Relativistic Jets depend on the Spin of Accreting Supermassive Black Hole

Theoretical models show that the power of relativistic jets of active galactic nuclei depends on the spin and mass of the central supermassive black holes, as well as the accretion. Here we report an analysis of archival observations of a sample of blazars. We find a significant correlation between jet kinetic power and the spin of supermassive black holes. At the same time, we use multiple linear regression to analyze the relationship between jet kinetic power and accretion, spin and black hole mass. We find that the spin of supermassive black holes and accretion are the most important contribution to the jet kinetic power. The contribution rates of both the spin of supermassive black holes and accretion are more than 95\%. These results suggest that the spin energy of supermassive black holes powers the relativistic jets. The jet production efficiency of almost all Fermi blazars can be explained by moderately thin magnetically arrested accretion disks around rapidly spinning black holes.

astro-ph.HE↗