scholarly journals The WISSH quasars project

2020 ◽  
Vol 635 ◽  
pp. A157 ◽  
Author(s):  
A. Travascio ◽  
L. Zappacosta ◽  
S. Cantalupo ◽  
E. Piconcelli ◽  
F. Arrigoni Battaia ◽  
...  
Keyword(s):  
Average Velocity ◽  
Rest Frame ◽  
Velocity Dispersion ◽  
High Redshift ◽  
Emission Lines ◽  
Host Galaxy ◽  
Uv Emission ◽  
Broad Emission ◽  
Highly Sensitive ◽  
Integral Field

Context. In recent years, Lyα nebulae have been routinely detected around high redshift, radio-quiet quasars thanks to the advent of the highly sensitive integral field spectrographs. Constraining the physical properties of the Lyα nebulae is crucial for a full understanding of the circum-galactic medium (CGM). The CGM acts both as a repository for intergalactic and galactic baryons as well as a venue of feeding and feedback processes. The most luminous quasars are privileged test-beds to study these processes, given their large ionising fluxes and dense CGM environments in which they are expected to be embedded. Aims. We aim to characterise the rest-frame ultraviolet (UV) emission lines in the CGM around a hyper-luminous, broad emission line, radio-quiet quasar at z ∼ 3.6, which exhibits powerful outflows at both nuclear and host galaxy scales. Methods. We analyse VLT/MUSE observations of the quasar J1538+08 (Lbol = 6 × 1047 erg s−1), and we performed a search for extended UV emission lines to characterise its morphology, emissivity, kinematics, and metal content. Results. We report the discovery of a very luminous (∼2 × 1044 erg s−1), giant Lyα nebula and a likely associated extended (75 kpc) CIV nebula. The Lyα nebula emission exhibits moderate blueshift (∼440 km s−1) compared to the quasar systemic redshift and a large average velocity dispersion (σ¯v ∼ 700 km s−1) across the nebula, while the CIV nebula shows average velocity dispersion of σ¯v ∼ 350 km s−1. The Lyα line profile exhibits a significant asymmetry towards negative velocity values at 20−30 kpc south of the quasar and is well parametrised by the following two Gaussian components: a narrow (σ ∼ 470 km s−1) systemic one plus a broad (σ ∼ 1200 km s−1), blueshifted (∼1500 km s−1) one. Conclusions. Our analysis of the MUSE observation of J1538+08 reveals metal-enriched CGM around this hyper-luminous quasar. Furthermore, our detection of blueshifted emission in the emission profile of the Lyα nebula suggests that powerful nuclear outflows can propagate through the CGM over tens of kiloparsecs.

scholarly journals Obscured AGN at 1.5 < z < 3.0 from the zCOSMOS-deep Survey

2019 ◽  
Vol 626 ◽  
pp. A9 ◽  
Author(s):  
M. Mignoli ◽  
A. Feltre ◽  
A. Bongiorno ◽  
F. Calura ◽  
R. Gilli ◽  
...  
Keyword(s):  
Physical Properties ◽  
Emission Line ◽  
Metal Content ◽  
High Redshift ◽  
Strong Relationship ◽  
Emission Lines ◽  
Host Galaxy ◽  
Host Galaxies ◽  
Uv Emission

Context. The physics and demographics of high-redshift obscured active galactic nuclei (AGN) is still scarcely investigated. New samples of such objects, selected with different techniques, can provide useful insights into their physical properties. Aims. With the goal to determine the properties of the gas in the emitting region of type 2 AGN, in particular, the gas metal content, we exploit predictions from photoionization models, including new parameterizations for the distance of gas distribution from the central source and internal microturbulence in the emitting clouds, to interpret rest-frame UV spectral data. Methods. We selected a sample of 90 obscured (type 2) AGN with 1.45 ≤ z ≤ 3.05 from the zCOSMOS-deep galaxy sample by 5σ detection of the high-ionization C IV λ1549 narrow emission line. This feature in a galaxy spectrum is often associated with nuclear activity, and the selection effectiveness has also been confirmed by diagnostic diagrams based on utraviolet (UV) emission-line ratios. We applied the same selection technique and collected a sample of 102 unobscured (type 1) AGN. Taking advantage of the large amount of multiband data available in the COSMOS field, we investigated the properties of the C IV-selected type 2 AGN, focusing on their host galaxies, X-ray emission, and UV emission lines. Finally, we investigated the physical properties of the ionized gas in the narrow-line region (NLR) of this type 2 AGN sample by combining the analysis of strong UV emission lines with predictions from photoionization models. Results. We find that in order to successfully reproduce the relative intensity of UV emission lines of the selected high-z type 2 AGN, two new ingredients in the photoionization models are fundamental: small inner radii of the NLR (≈90 pc for LAGN = 1045 erg s−1), and the internal dissipative microturbulence of the gas-emitting clouds (with vmicr ≈ 100 km s−1). With these modified models, we compute the gas-phase metallicity of the NLR, and our measurements indicate a statistically significant evolution of the metal content with redshift. Finally, we do not observe a strong relationship between the NLR gas metallicity and the stellar mass of the host galaxy in our C IV-selected type 2 AGN sample.

scholarly journals X-ray properties of dust-obscured galaxies with broad optical/UV emission lines

2020 ◽  
Vol 499 (2) ◽  
pp. 1823-1840
Author(s):  
Fan Zou (邹凡) ◽  
William N Brandt ◽  
Fabio Vito ◽  
Chien-Ting Chen (陳建廷) ◽  
Gordon P Garmire ◽  
...  
Keyword(s):  
Rest Frame ◽  
Emission Lines ◽  
Host Galaxy ◽  
Broad Line ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Uv Emission ◽  
Black Hole Growth ◽  
Hole Growth ◽  
Rule Out

ABSTRACT Dust-obscured galaxies (DOGs) with extreme infrared luminosities may represent a key phase in the co-evolution of galaxies and supermassive black holes. We select 12 DOGs at 0.3 ≲ z ≲ 1.0 with broad Mg ii or H β emission lines and investigate their X-ray properties utilizing snapshot observations (∼3 ks per source) with Chandra. By assuming that the broad lines are broadened due to virial motions of broad-line regions, we find that our sources generally have high Eddington ratios (λEdd). Our sources generally have moderate intrinsic X-ray luminosities (LX ≲ 1045 erg s−1), which are similar to those of other DOGs, but are more obscured. They also present moderate outflows and intense starbursts. Based on these findings, we conclude that high-λEdd DOGs are closer to the peaks of both host-galaxy and black hole growth compared to other DOGs, and that (active galactic nucleus) AGN feedback has not swept away their reservoirs of gas. However, we cannot fully rule out the possibility that the broad lines are broadened by outflows, at least for some sources. We investigate the relations among LX, AGN rest-frame 6 μm monochromatic luminosity, and AGN bolometric luminosity, and find the relations are consistent with the expected ones.

scholarly journals THE SINS SURVEY: BROAD EMISSION LINES IN HIGH-REDSHIFT STAR-FORMING GALAXIES

2009 ◽  
Vol 701 (2) ◽  
pp. 955-963 ◽  
Author(s):  
Kristen L. Shapiro ◽  
Reinhard Genzel ◽  
Eliot Quataert ◽  
Natascha M. Förster Schreiber ◽  
Richard Davies ◽  
...  
Keyword(s):  
High Redshift ◽  
Emission Lines ◽  
Star Forming ◽  
Broad Emission

scholarly journals MUSE-AO view of the starburst–AGN connection: NGC 7130

2019 ◽  
Vol 621 ◽  
pp. L5 ◽  
Author(s):  
J. H. Knapen ◽  
S. Comerón ◽  
M. K. Seidel
Keyword(s):  
Adaptive Optics ◽  
Spatial Resolution ◽  
Field Data ◽  
Velocity Dispersion ◽  
Field Of View ◽  
Host Galaxy ◽  
Gas Velocity ◽  
Star Forming ◽  
Optical Wavelengths ◽  
Integral Field

We present the discovery of a small kinematically decoupled core of 0.″2 (60 pc) in radius as well as an outflow jet in the archetypical AGN–starburst “composite” galaxy NGC 7130 from integral field data obtained with the adaptive optics-assisted MUSE-NFM instrument on the VLT. Correcting the already good natural seeing at the time of our science verification observations with the four-laser GALACSI AO system, we reach an unprecedented spatial resolution at optical wavelengths of around 0.″15. We confirm the existence of star-forming knots arranged in a ring of 0.″58 (185 pc) in radius around the nucleus, previously observed from UV and optical Hubble Space Telescope and CO(6-5) ALMA imaging. We determine the position of the nucleus as the location of a peak in gas velocity dispersion. A plume of material extends towards the NE from the nucleus until at least the edge of our field of view at 2″ (640 pc) radius which we interpret as an outflow jet originating in the AGN. The plume is not visible morphologically, but is clearly characterised in our data by emission-line ratios characteristic of AGN emission, enhanced gas velocity dispersion, and distinct non-circular gas velocities. Its orientation is roughly perpendicular to the line of nodes of the rotating host galaxy disc. A circumnuclear area of positive and negative velocities of 0.″2 in radius indicates a tiny inner disc, which can only be seen after combining the integral field spectroscopic capabilities of MUSE with adaptive optics.

Gas flows in a changing-look AGN

2019 ◽  
Vol 15 (S359) ◽  
pp. 334-338
Author(s):  
Sandra I. Raimundo
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Host Galaxy ◽  
Gas Flows ◽  
Broad Emission ◽  
The Galaxy ◽  
Low Activity

AbstractThe galaxy Mrk 590 is one of the few known ‘changing-look’ Active Galactic Nuclei (AGN) to have transitioned between states twice, having just increased its flux after a period of ˜10 years of low activity. In addition to the increase in flux, the optical broad emission lines have reappeared but show a different profile than what was observed before they disappeared. The gas motions in the host galaxy of this changing-look AGN show outflows and dynamical structures able to drive gas to the nucleus, suggesting an interplay between inflow and outflow in the centre of the galaxy.

An Emission Line Model for AM Herculis Systems: Application to E1405-451

1987 ◽  
Vol 7 (2) ◽  
pp. 119-122 ◽  
Author(s):  
Lilia Ferrario ◽  
D. T. Wickramasinghe ◽  
I. R. Tuohy
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
Velocity Dispersion ◽  
Orbital Plane ◽  
Emission Lines ◽  
Lagrange Point ◽  
Broad Emission ◽  
Straight Line ◽  
Dispersion Data ◽  
The Magnetic Field

AbstractThe optical spectra of the AM Herculis binaries are characterized by extremely complex emission lines whose profiles can be resolved into at least three components which are formed in different regions of the accretion stream leading from the companion star towards the magnetic white dwarf. We present a theoretical model which localizes the formation region of the broad emission line component and provides information regarding the structure of this emitting region. In our model the particle trajectories are integrated in a Roche potential and the volume between the white dwarf and the companion has been divided into two different regimes of motion. In one region the gas escapes from the secondary near the inner Lagrange point and is accelerated along a straight line towards the white dwarf. In the other region the magnetic field is strong enought to divert the gas out of the orbital plane and to channel it towards the white dwarfs surface. The model has been used to interpret radial velocity and velocity dispersion data from the AM Herculis system E1405-451.

Ionized gas outflows in the interacting radio galaxy 4C +29.30

2019 ◽  
Vol 15 (S359) ◽  
pp. 262-264
Author(s):  
Guilherme S. Couto ◽  
Thaisa Storchi-Bergmann ◽  
Aneta Siemiginowska ◽  
Rogemar A. Riffel
Keyword(s):  
Velocity Dispersion ◽  
Radio Galaxy ◽  
Host Galaxy ◽  
Ionized Gas ◽  
Bolometric Luminosity ◽  
Integral Field Spectroscopy ◽  
Outflow Rate ◽  
Mass Outflow ◽  
Ambient Gas ◽  
Integral Field

AbstractWe investigate the ionized gas excitation and kinematics in the inner 4.3 × 6.2 kpc2 of the merger radio galaxy 4C +29.30. Using optical integral field spectroscopy with the Gemini North Telescope, we find signatures of gas outflows, including high blueshifts of up to ∼−650 km s−1 observed in a region ∼1″ south of the nucleus, which also presents high velocity dispersion (∼250 km s−1). A possible redshifted counterpart is observed north from the nucleus. We propose that these regions correspond to a bipolar outflow possibly due to the interaction of the radio jet with the ambient gas. We estimate a total ionized gas mass outflow rate of $\[{\dot M_{out}}&#x2009;=&#x2009;18.1\begin{array}{c}&#x2009;+&#x2009;8.2\\ - 5.3\end{array}{\kern 1pt} {\kern 1pt} \]$ with a kinetic power of $\[\dot E&#x2009;=&#x2009;5.8\begin{array}{c}&#x2009;+&#x2009;7.6\\ - 2.9\end{array} \times {10^{42}}{\kern 1pt} {\kern 1pt} \]$ , which represents $\[3.9\begin{array}{c}&#x2009;+&#x2009;5.1\\ - 1.5\end{array}\% \]$ of the AGN bolometric luminosity. These values are higher than usually observed in nearby active galaxies and could imply a significant impact of the outflows on the evolution of the host galaxy.

scholarly journals Rest-frame UV spectroscopy of extreme [OIII] emitters at 1.3 < z < 3.7: Toward a high-redshift UV reference sample for JWST

2020 ◽  
Author(s):  
Mengtao Tang ◽  
Daniel P Stark ◽  
Jacopo Chevallard ◽  
Stéphane Charlot ◽  
Ryan Endsley ◽  
...  
Keyword(s):  
Rest Frame ◽  
Uv Spectroscopy ◽  
High Redshift ◽  
Reference Sample ◽  
Line Emission ◽  
Uv Emission ◽  
Consistent Picture ◽  
Low Metallicity ◽  
Extreme Sensitivity ◽  
Galaxy Population

Abstract Deep spectroscopy of galaxies in the reionization era has revealed intense C III] and C IV line emission (EW &gt;15 − 20 Å). In order to interpret the nebular emission emerging at z &gt; 6, we have begun targeting rest-frame UV emission lines in galaxies with large specific star formation rates (sSFRs) at 1.3 &lt; z &lt; 3.7. We find that C III] reaches the EWs seen at z &gt; 6 only in large sSFR galaxies with [O III]+Hβ EW &gt;1500 Å. In contrast to previous studies, we find that many galaxies with intense [O III] have weak C III] emission (EW =5 − 8 Å), suggesting that the radiation field associated with young stellar populations is not sufficient to power strong C III]. Photoionization models demonstrate that the spread in C III] among systems with large sSFRs ([O III]+Hβ EW &gt;1500 Å) is driven by variations in metallicity, a result of the extreme sensitivity of C III] to electron temperature. We find that the strong C III] emission seen at z &gt; 6 (EW &gt;15 Å) requires metal poor gas (≃ 0.1 Z⊙) whereas the weaker C III] emission in our sample tends to be found at moderate metallicities (≃ 0.3 Z⊙). The luminosity distribution of the C III] emitters in our z ≃ 1 − 3 sample presents a consistent picture, with stronger emission generally linked to low luminosity systems (MUV &gt; −19.5) where low metallicities are more likely. We quantify the fraction of strong C III] and C IV emitters at z ≃ 1 − 3, providing a baseline for comparison against z &gt; 6 samples. We suggest that the first UV line detections at z &gt; 6 can be explained if a significant fraction of the early galaxy population is found at large sSFR (&gt;200 Gyr−1) and low metallicity (&lt;0.1 Z⊙).

scholarly journals Broad Emission Lines in AGN: Phenomenology and Models

1999 ◽  
Vol 194 ◽  
pp. 285-289
Author(s):  
Jack W. Sulentic ◽  
Paolo Marziani ◽  
Massimo Calvani ◽  
Deborah Dultzin-Hacyan
Keyword(s):  
Accretion Disk ◽  
Rest Frame ◽  
Emission Lines ◽  
Narrow Line ◽  
X Ray ◽  
Broad Emission ◽  
Local Rest Frame ◽  
Source Orientation ◽  
Significant Line

We review the phenomenology of broad emission lines in AGN. We show that velocity displacements relative to the local rest frame of Hβ and CIVλ1549 are real. The most significant line displacement result involves a systematic blueshift for CIV, seen only in radio-quiet sources. We find some evidence that the amplitude of this displacement may correlate with source orientation. We show that disagreement between different studies of the CIV line properties is due to whether or not a narrow line component was subtracted. Finally, we consider evidence that optical and X-ray broad lines arise in an accretion disk. We show that the evidence for a disk origin is far from overwhelming for both Hβ and FeKα.

scholarly journals Dichotomy of radio loud and radio quiet quasars in four dimensional eigenvector one (4DE1) parameter space

2019 ◽  
Vol 15 (S356) ◽  
pp. 351-354
Author(s):  
Shimeles Terefe ◽  
Ascensión del Olmo ◽  
Paola Marziani ◽  
Mirjana Pović
Keyword(s):  
Emission Line ◽  
Parameter Space ◽  
Signal To Noise Ratio ◽  
High Redshift ◽  
Emission Lines ◽  
Signal To Noise ◽  
Broad Emission ◽  
Broad Emission Line ◽  
Two Populations ◽  
Calar Alto

AbstractRecent work has shown that it is possible to systematize quasars (QSOs) spectral diversity in 4DE1 parameter space. The spectra contained in most of the surveys have low signal to noise ratio which fed the impression that all QSO’s are spectroscopically similar. Exploration of 4DE1 parameter space gave rise to the concept of two populations of QSOs that present important spectroscopic differences. We aim to quantify broad emission line differences between radio quiet and radio loud sources by exploiting more complete samples of QSO with spectral coverage in Hβ, MgII and CIV emission lines. We used a high redshift sample (0.35 < z < 1) of strong radio emitter QSOs observations from Calar Alto Observatory in Spain.

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