arXiv subjects

Peng Jiang

Publications and source records attributed to Peng Jiang.

At least 343 records · Page 19Linked to original sources

arXiv2018

Multi-Source Pointer Network for Product Title Summarization

In this paper, we study the product title summarization problem in E-commerce applications for display on mobile devices. Comparing with conventional sentence summarization, product title summarization has some extra and essential constraints. For example, factual errors or loss of the key information are intolerable for E-commerce applications. Therefore, we abstract two more constraints for product title summarization: (i) do not introduce irrelevant information; (ii) retain the key information (e.g., brand name and commodity name). To address these issues, we propose a novel multi-source pointer network by adding a new knowledge encoder for pointer network. The first constraint is handled by pointer mechanism. For the second constraint, we restore the key information by copying words from the knowledge encoder with the help of the soft gating mechanism. For evaluation, we build a large collection of real-world product titles along with human-written short titles. Experimental results demonstrate that our model significantly outperforms the other baselines. Finally, online deployment of our proposed model has yielded a significant business impact, as measured by the click-through rate.

cs.CL↗

arXiv2018

A Strange EUV Emission: Scattered Continuum in the Lymann Limit Absorption Edge toward the Quasar SDSS J125903.26+621211.5?

We identified a peculiar proximate sub-damped Lya absorption system (sub-DLA) at z=3.234 with a neutral hydrogen column density of $N_{H} =10^{19.70\pm0.15}~\rm cm^{-2}$ toward the quasar SDSS J125903.26+621211.5 in two epoch optical spectra of the Sloan Digital Sky Survey. We detected Lya residue in the proximate sub-DLA trough at $> 8σ$ level. To our surprise, extreme ultraviolet (EUV) continuum emission is significantly ($> 4σ$) detected in the corresponding Lymann limit absorption edge at both of the FUV and NUV bands by the Galaxy Evolution Explorer. The high neutral hydrogen column density should allow a negligible transmission of both the Lya line photons and EUV continuum photons due to the high optical depth of the gas. The possible scenarios of foreground galaxy contamination, partial coverage, emission from the quasar host galaxy, and extended Lya emission are excluded in turn, and we speculate that the residual Lya and EUV emission is due to photons scattering (broad Lya and the continuum emission) of electrons residing at a spatial scale larger than that of the proximate sub-DLA. Electron scattering is wavelength-independent, the scattered light is therefore a copy of the incident spectrum that might originate in the accretion disk. With the assistances from the neutral hydrogen absorbers as the "natural coronagraph" and the scatterers as the "natural mirror", we yielded a very hard EUV spectral index of $α= 0.65\pm 0.25$ ($F_ν\propto ν^α$), consistent with the standard picture of the locally heated accretion disk in the inner EUV-emitting radii, as well as in the outer near-infrared-emitting radii suggested by Kishimoto et al. (2008).

astro-ph.GA↗

arXiv2018

Design of Near Infrared Sky Brightness Monitor and Test Running at Ngari Observatory in Tibet

Tibet is known as the third pole of the earth, as high as the South Pole and North Pole. The Ngari (Ali) observatory in Tibet has the advantage of plenty of photometric night, low precipitable water vapor, high transmittance, good seeing. It is a good site, and promising to be one of the best place for infrared and submillimeter observations in the world. However, there is no data available for sky background brightness in such place, which restrict the astronomical development of the sites. In the near infrared band of J, H, Ks, a NIR sky brightness monitor (NISBM) is designed based on InGaAs photoelectric diode. By using the method of chopper modulation and digital lock-in amplifier processing, the SNR (Signal Noise Ratio), detectivity and the data acquisition speed of the device is greatly improved. For each band of J, H, Ks, an independent instrument is designed and calibrated in laboratory. The NISBM has been installed in Ngari observatory in July of 2017 and obtained the first data of NIR sky brightness at Ngari observatory.

astro-ph.IM↗

arXiv2018

The operational and control software of Multi-channel Antarctic Solar Telescope

MARST (Multi-channel Antarctic Solar Telescope) aims to observe the Sun in multiple wavebands in Antarctica and will be China's first solar telescope in Antarctica. The telescope has two tubes, corresponding to Photosphere observation which uses 11 filters and Chromosphere observation in Hα waveband. The two tubes need to be coordinated to observe at the same time. The telescope will observe the Sun for a long time, so a self-guiding module is needed to improve sun tracking. Besides, performing solar specific flat-field exposure is necessary for analyzing. EPICS is introduced to control each hardware and an autonomous observation system based on RTS2 is designed under such demands. EPICS application modules are implemented for each device: telescope mount & focuser, filter wheel, Hα filter, dome with webcams, Andor CCD and PI CCD. We also integrate EPICS modules into RTS2 framework with an XML format configuration. To control these applications autonomously we have developed a RTS2 executor module where two plan classes are instantiated to control two sets of filters and CCDs, and to ensure only one could control the mount at the same time. Different types of observation plans are designed to describe different series of processes with different priorities. To improve sun tracking, we calculate the centroid of each image to get the offset, then apply the correction to the telescope during observation process. For frontend users, a GUI based on PyQt5 and QML is implemented and connects to rts2-httpd and rts2-proxy modules so that users can control devices, check images and get logs.

astro-ph.IM↗

arXiv2018

Ultra-dense Broad-line Region Scale Outflow in Highly Reddened Quasar SDSS J145057.28+530007.6

We report the discovery of highly reddening and hydrogen Balmer and metastable helium broad absorption lines in the quasar SDSS J145057.28+530007.6, based on the optical and near-infrared spectra taken from the SDSS-III/BOSS and the TripleSpec observations. The nuclear continuum, Balmer decrement and absorption-line depth analyses suggest that (1) the accretion disk is completely obscured and the covering factor of the broad-line region (BLR) is only $0.39\pm0.03$, (2) the power-law continuum is reddened by the SMC extinction law of $E(B-V )=0.72\pm 0.01$ mag and the dusty materials are mainly associated with \ion{Ca}{2} H and K rather than the Balmer and \ion{He}{1}* absorption-line system, (3) the unsaturated Balmer (H$β$, H$γ$, and H$δ$) and \ion{He}{1}* $\lambda3889$ absorption lines have same two-Gaussian profiles with the shifts of $-931\pm33$ and $-499\pm39$ km s$^{-1}$ and the widths of $121\pm28$ and $196\pm37$ km s$^{-1}$, respectively. Constrained mutually by the Balmer, \ion{He}{1}* absorption lines and undetected \ion{Fe}{2}* $\lambda5169$ in the photoionization simulations, the physical properties of the outflow gases are derived as follows: ionization parameter $10^{-1.4} \lesssim U \lesssim 10^{-0.8}$, density $10^{8.2\pm0.4} \lesssim n_{\rm H} \lesssim 10^{9.0\pm0.4}$ cm$^{-3}$, and column density $10^{22.0\pm0.2} \lesssim N_{\rm H} \lesssim 10^{22.2-22.3}$ cm$^{-2}$. We propose that the ultra-dense outflow gases appear in the vicinity of the surface of the BLR or are located at most 3.12 pc away from the engine. That probably implies that the outflow originates from the BLR, and this kind of ultra-dense BLR scale outflow gases can effectively test the physical properties of the outer gases of the BLR.

astro-ph.GA↗

arXiv2018

DiDA: Disentangled Synthesis for Domain Adaptation

Unsupervised domain adaptation aims at learning a shared model for two related, but not identical, domains by leveraging supervision from a source domain to an unsupervised target domain. A number of effective domain adaptation approaches rely on the ability to extract discriminative, yet domain-invariant, latent factors which are common to both domains. Extracting latent commonality is also useful for disentanglement analysis, enabling separation between the common and the domain-specific features of both domains. In this paper, we present a method for boosting domain adaptation performance by leveraging disentanglement analysis. The key idea is that by learning to separately extract both the common and the domain-specific features, one can synthesize more target domain data with supervision, thereby boosting the domain adaptation performance. Better common feature extraction, in turn, helps further improve the disentanglement analysis and disentangled synthesis. We show that iterating between domain adaptation and disentanglement analysis can consistently improve each other on several unsupervised domain adaptation tasks, for various domain adaptation backbone models.

cs.CV↗

arXiv2018

An Intercomparison Study of Two Proximate Damped Ly$α$ Systems with Residual Flux upon the Ly$α$ Absorption Trough toward Quasars

In this paper, we present an intercomparison study of two quasars, SDSS J145618.32+340037.2 and SDSS J215331.50-025514.1, which have proximate damped Lya systems (PDLAs) with residual flux upon the Lya absorption trough. Though they both have residual flux as luminous as $10^{43}erg/s$, their PDLAs are quite different in, e.g., HI column density, metal line absorption strength, high-ionization absorption lines as well as residual flux strength. For J1456, the HI column density is $20.6\pm0.2$, with za=2.3138, nearly identical to the quasar redshift (z=2.3142) determined from the [OIII] emission line. The metallicity of this system is typical of DLAs and there is high ionization therein, suggesting that the PDLA system is multiphase, putting it in the quasar environment. For J2153, we measure the HI column density to be $21.5\pm0.1$ at za=3.511, slightly redshifted with respect to the quasar (z=3.490) measured from CIII]. The metallicity of this system is quite low and there is a lack of significant high-ionization absorption lines therein, suggesting that the system is beyond the quasar host galaxy. The residual flux is wide (1000 km/s) in J1456, with a significance of $8σ$, while also wide (1500 km/s) but with a smaller significance of $3σ$ in J2153. Among many explanations, we find that Lya fuzz or resonant scattering can be used to explain the residual flux in the two sources while partial coverage cannot be excluded for J1456. By comparing these two cases, together with similar cases reported previously, we suggest that the strength of the residual flux is related to properties such as metallicity and high-ionization absorption lines of PDLAs. The residual flux recorded upon the PDLA absorption trough opens a window for us to see the physical conditions and processes of the quasar environment, and their profile and strength further remind us of their spatial scales.

astro-ph.GA↗

arXiv2018

Considerations for a Multi-beam Multi-purpose Survey with FAST

Having achieved 'first-light' right before the opening ceremony on September 25, 2016, the Five-hundred-meter Aperture Spherical radio Telescope (FAST) is being busily commissioned. Its innovative design requires ~1000 points to be measured and driven instead of just the two axes of motion, e.g. Azimuth and Elevation for most of the conventional antennae, to realize pointing and tracking. We have devised a survey plan to utilized the full sensitivity of FAST, while minimizing the complexities in operation the system. The 19-beam L band focal plan array will be rotated to specific angles and taking continuous data streams while the surface shape and the focal cabin stay fixed. Such a survey will cover the northern sky in about 220 full days. Our aim is to obtain data for pulsar search, HI (neutral hydrogen) galaxies, HI imaging, and radio transients, simultaneously, through multiple backends. These data sets could be a significant contribution to all related fields in radio astronomy and remain relevant for decades.

astro-ph.IM↗

arXiv2017

Origin of charge transfer and enhanced electron-phonon coupling in single unit-cell FeSe films on SrTiO3

Interface charge transfer and electron-phonon coupling have been suggested to play a crucial role in the recently discovered high-temperature superconductivity of single unit-cell FeSe films on SrTiO3. However, their origin remains elusive. Here, using ultraviolet photoemission spectroscopy (UPS) and element-sensitive X-ray photoemission spectroscopy (XPS), we identify the strengthened Ti-O bond that contributes to the interface enhanced electron-phonon coupling and unveil the band bending at the FeSe/SrTiO3 interface that leads to the charge transfer from SrTiO3 to FeSe films. We also observe band renormalization that accompanies the onset of superconductivity. Our results not only provide valuable insights into the mechanism of the interface-enhanced superconductivity, but also point out a promising route towards designing novel superconductors in heterostructures with band-bending induced charge transfer and interfacial enhanced electron-phonon coupling.

cond-mat.supr-con↗

arXiv2017

Searching for the Transit of the Earth--mass exoplanet Proxima~Centauri~b in Antarctica: Preliminary Result

Proxima Centauri is known as the closest star from the Sun. Recently, radial velocity observations revealed the existence of an Earth-mass planet around it. With an orbital period of ~11 days, the surface of Proxima Centauri b is temperate and might be habitable. We took a photometric monitoring campaign to search for its transit, using the Bright Star Survey Telescope at the Zhongshan Station in Antarctica. A transit-like signal appearing on 2016 September 8th, is identified tentatively. Its midtime, $T_{C}=2,457,640.1990\pm0.0017$ HJD, is consistent with the predicted ephemeris based on RV orbit in a 1$σ$ confidence interval. Time-correlated noise is pronounced in the light curve of Proxima Centauri, affecting detection of transits. We develop a technique, in a Gaussian process framework, to gauge the statistical significance of potential transit detection. The tentative transit signal reported here, has a confidence level of $2.5σ$. Further detection of its periodic signals is necessary to confirm the planetary transit of Proxima Centauri b. We plan to monitor Proxima Centauri in next Polar night at Dome A in Antarctica, taking the advantage of continuous darkness. \citet{Kipping17} reported two tentative transit-like signals of Proxima Centauri b, observed by the Microvariability and Oscillation of Stars space Telescope in 2014 and 2015, respectively. The midtransit time of our detection is 138 minutes later than that predicted by their transit ephemeris. If all the signals are real transits, the misalignment of the epochs plausibly suggests transit timing variations of Proxima Centauri b induced by an outer planet in this system.

astro-ph.EP↗

arXiv2017

Reddening and He I* $\lambda10830$ Absorption Lines in Three Narrow-line Seyfert 1 Galaxies

We report the detection of heavy reddening and the He I* $\lambda10830$ absorption lines at the AGNs' redshift in three Narrow-line Seyfert 1 galaxies: SDSS J091848.61+211717.0, SDSS J111354.66+124439.0, and SDSS J122749.13+321458.9. They exhibit very red optical to near-infrared colors, narrow Balmer/Paschen broad emission lines and He I* $\lambda10830$ absorption lines. The ultraviolet-optical-infrared nucleus continua are reddened by the SMC extinction law of $E(B-V)\sim 0.74$, 1.17, and 1.24 mag for three objects, which are highly consistent with the values obtained from the broad-line Balmer decrements, but larger than those of narrow emission lines. The reddening analysis suggests the extinction dust simultaneously obscure the accretion disk, the broad emission line region, and the hot dust from the inner edge of the torus. It is possible that the dust obscuring the AGN structures are the dusty torus itself. Furthermore, the Cloudy analysis of the He I* $\lambda10830$ absorption lines propose the distance of the absorption materials to be the extend scale of the torus. That greatly increases probabilities of the obscure and absorption materials being the dusty torus.

astro-ph.GA↗

arXiv2017

Photoionization-driven Absorption Lines Variability in Balmer Absorption Line Quasar LBQS 1206+1052

In this paper we present an analysis of absorption line variability in mini-BAL quasar LBQS 1206+1052. The SDSS spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of $\sim$700 km s$^{-1}$ and $\sim$1400 km s$^{-1}$ relative to the quasar rest-frame. The former component shows rare Balmer absorption, which is an indicator of high density absorbing gas, thus the quasar is worth follow-up spectroscopic observations. Our follow-up optical and near-infrared spectra using MMT, YFOSC, TripleSpec and DBSP reveal that the strengths of the absorption lines vary for both of the two components, while the velocities do not change. We reproduce all of the spectral data by assuming that only the ionization state of the absorbing gas is variable and that all other physical properties are invariable. The variation of ionization is consistent with the variation of optical continuum from the V-band light-curve. Additionally, we can not interpret the data by assuming that the variability is due to a movement of the absorbing gas. Therefore, our analysis strongly indicates that the absorption line variability in LBQS 1206+1052 is photoionization-driven. As shown from photo-ionization simulations, the absorbing gas with blueshift velocity of $\sim$700 km s$^{-1}$ has a density in the range of $10^9$ to $10^{10}$ cm$^{-3}$ and a distance of $\sim$1 pc, and the gas with blueshift velocity of $\sim$1400 km s$^{-1}$ has a density of $10^3$ cm$^{-3}$ and a distance of $\sim$1 kpc.

astro-ph.GA↗

arXiv2017

Ultraviolet and Optical Emission-line Outflows in the Heavily Obscured Quasar SDSS J000610.67+121501.2: At the Scale of the Dusty Torus and Beyond

Broad emission-line outflows of active galactic nuclei (AGNs) have been proposed for many years but are very difficult to quantitatively study because of the coexistence of the gravitationally-bound and outflow emission. We present detailed analysis of a heavily reddened quasar, SDSS J000610.67+121501.2, whose normal ultraviolet (UV) broad emission lines (BELs) are heavily suppressed by the Dusty Torus as a natural "Coronagraph", thus the blueshifted BELs (BBELs) can be reliably measured. The physical properties of the emission-line outflows are derived as follows: ionization parameter $U \sim 10^{-0.5}$, column density $N_{\rm H}\sim 10^{22.0}$ cm$^{-2}$, covering fraction of $\sim 0.1$ and upper limit density of $n_{\rm H}\sim 10^{5.8}$ cm$^{-3}$. The outflow gases are located at least 41 pc away from the central engine, which suggests that they have expanded to the scale of the dust torus or beyond. Besides, Lya shows a narrow symmetric component, to our surprise, which is undetected in any other lines. After inspecting the narrow emission-line region and the starforming region as the origin of the Lya narrow line, we propose the end-result of outflows, diffusing gases in the larger region, acts as the screen of Lya photons. Future high spatial resolution spectrometry and/or spectropolarimetric observation are needed to make a final clarification.

astro-ph.GA↗

arXiv2016

The Redshifted Hydrogen Balmer and Metastable He I Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec Scale Accretion Inflow?

The accretion of interstellar medium onto the central super massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. But few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example, in which the rarely detected hydrogen Balmer and metastable He I absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg II, Fe II, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He I* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find the absorbing medium is exposed to the radiation with ionization parameter $U\approx 10^{-1.8}$, and the density is $n(\mathrm{H})\approx 10^9\ \mathrm{cm}^{-3}$. Thus the absorbing medium is located $\sim 4\ \mathrm{pc}$ away from the central engine. According to the similarity in the distance and physical conditions between the absorbing medium and the torus, we strongly propose the absorption line system as a candidate for the accretion inflow which originates from the inner surface of the torus.

astro-ph.GA↗

arXiv2016

Very Low-Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS VI: A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646

We report the detections of a giant planet (MARVELS-7b) and a brown dwarf candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using ET at Kitt Peak National Observatory, HRS at HET, the "Classic" spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary. HD 87646 is a close binary with a separation of $\sim22$ AU between the two stars, estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has Teff = 5770$\pm$80K, log(g)=4.1$\pm$0.1 and [Fe/H] = $-0.17\pm0.08$. The derived minimum masses of the two substellar companions of HD 87646A are 12.4$\pm$0.7M$_{\rm Jup}$ and 57.0$\pm3.7$M$_{\rm Jup}$. The periods are 13.481$\pm$0.001 days and 674$\pm$4 days and the measured eccentricities are 0.05$\pm$0.02 and 0.50$\pm$0.02 respectively. Our dynamical simulations show the system is stable if the binary orbit has a large semi-major axis and a low eccentricity, which can be verified with future astrometry observations.

astro-ph.EP↗

arXiv2016

SDSS J163459.82+204936.0: A Ringed Infrared-Luminous Quasar with Outflows in both Absorption and Emission Lines

SDSS J1634+2049 is a local (z = 0.1293) infrared-luminous quasar with LIR= 10^11.91 Lsun. We present a detailed multiwavelength study of both the host galaxy and the nucleus. The host galaxy demonstrates violent, obscured star formation activities with SFR ~ 140 Msun yr^-1, estimated from either the PAH emission or IR luminosity. The optical to NIR spectra exhibit a blueshifted narrow cuspy component in Hb, HeI5876,10830 and other emission lines consistently with an offset velocity of ~900 km/s, as well as additional blueshifting phenomena in high-ionization lines , while there exist blueshifted broad absorption lines (BALs) in NaID and HeI*3889,10830, indicative of the AGN outflows producing BALs and emission lines. Constrained mutually by the several BALs with CLOUDY, the physical properties of the absorption-line outflow are derived as follows: 10^4 < n_H <= 10^5 cm^-3, 10^-1.3 <= U <= 10^-0.7 and 10^22.5<= N_H <= 10^22.9 cm^-2 , similar to those derived for the emission-line outflows. The similarity suggests a common origin. Taking advantages of both the absorption lines and outflowing emission lines, we find that the outflow gas is located at a distance of 48 - 65 pc from the nucleus, and that the kinetic luminosity of the outflow is 10^44-10^46 erg s^-1. J1634+2049 has a off-centered galactic ring on the scale of ~ 30 kpc that is proved to be formed by a recent head-on collision by a nearby galaxy. Thus this quasar is a valuable object in the transitional phase emerging out of dust enshrouding as depicted by the co-evolution scenario.

astro-ph.GA↗

arXiv2016

Strong Ly alpha Emission in the Proximate Damped Ly alpha Absorption Trough toward the Quasar SDSS J095253.83+011422.0

SDSS J095253.83+011422.0 (SDSS J0952+0114) was reported by Hall et al. (2004) as an exotic quasar at $z_{\rm em}=3.020$. In contrast to prominent broad metal--line emissions with FWHM~9000 km/s, only a narrow Ly αemission line is present with FWHM~1000 km/s. The absence of broad Ly alpha emission line has been a mystery for more than a decade. In this paper, we demonstrate that this is due to dark Proximate Damped Ly alpha Absorption (PDLA) at $z_{\rm abs}=3.010$ by identifying associated Lyman absorption line series from the damped Ly beta up to Ly9, as well as the Lyman limit absorption edge. The PDLA cloud has a column density of $\log N_{\rm H\,I}({\rm cm}^{-2})=21.8\pm0.2$, a metallicity of [Zn/H]$>-1.0$, and a spatial extent exceeding the Narrow Emission Line Region (NELR) of the quasar. With a luminosity of $L_{{\rm Ly}α}\sim10^{45}$ erg s$^{-1}$, the residual Ly alpha emission superposed on the PDLA trough is of two orders of magnitude stronger than previous reports. This is best explained as re-radiated photons arising from the quasar outflowing gas at a scale larger than the NELR. The PDLA here, acting like a natural coronagraph, provides us with a good insight into the illuminated gas in the vicinity of the quasar, which are usually hard to resolve due to their small size and "seeing fuzz" of bright quasars. Notably, SDSS J0952+0114 analogs might be easily omitted in the spectroscopic surveys of DLAs and PDLAs, as their damped Ly alpha troughs can be fully filled by additional strong Ly alpha emissions. Our preliminary survey shows that such systems are not very rare. They are potentially a unique sample for probing strong quasar feedback phenomena in the early universe.

astro-ph.GA↗

arXiv2015

Keck/ESI Long-slit Spectroscopy of SBS 1421+511: A Recoiling Quasar Nucleus in An Active Galaxy Pair?

We present Keck/ESI long-slit spectroscopy of SBS 1421+511, a system consisting of a quasar at z = 0.276 and an extended source 3" northern to the quasar. The quasar shows a blue-skewed profile of Balmer broad emission lines, which can be well modeled as emissions from a circular disk with a blueshift velocity of ~1400 km/s. The blueshift is better interpreted as resulting from a recoiling active black hole than from a super-massive black hole binary, since the line profile almost kept steady over one decade in the quasar rest-frame. Alternative interpretations are possible as well, such as emissions from a bipolar outflow or a circular disk with spiral emissivity perturbations. The extended source shows Seyfert-like narrow line ratios and a [OIII] luminosity of >1.4\times10^8L_\odot, with almost the same redshift as the quasar and a projected distance of 12.5 kpc at the redshift. SBS 1421+511 is thus likely to be an interacting galaxy pair with dual AGN. Alternatively, the quasar companion only appears to be active but not necessarily so: the gas before/in/behind the companion galaxy is illuminated by the quasar as an extended emission line region is detected at a similar distance in the opposite direction southern to the quasar, which may be generated either by tidal interactions between the galaxy pair or large-scale outflows from the quasar.

astro-ph.GA↗