scholarly journals Discovery of a dual AGN at z ≃ 3.3 with 20 kpc separation

2018 ◽  
Vol 610 ◽  
pp. L7 ◽  
Author(s):  
B. Husemann ◽  
G. Worseck ◽  
F. Arrigoni Battaia ◽  
T. Shanks
Keyword(s):  
Black Holes ◽  
Emission Line ◽  
Active Galactic Nucleus ◽  
Stellar Object ◽  
Emission Lines ◽  
Narrow Line ◽  
Hierarchical Assembly ◽  
High Ionization ◽  
Current Paradigm ◽  
Narrow Emission

A prediction of the current paradigm of the hierarchical assembly of galaxies is the presence of supermassive dual black holes at separations of a few kpc or less. In this context, we report the detection of a narrow-line emitter within the extended Lyα nebula (~120 kpc diameter) of the luminous radio-quiet quasi-stellar object (QSO) LBQS 0302–0019 at z = 3.286. We identify several high-ionization narrow emission lines (He II, C IV, C III) associated with this point-like source, which we have named “Jil”, which is only ~20 kpc (2.̋9) away from the QSO in projection. Emission-line diagnostics confirm that the source is likely powered by photoionization of an obscured active galactic nucleus (AGN) three orders of magnitude fainter than the QSO. The system represents the tightest unobscured/obscured dual AGN currently known at z > 3, highlighting the power of MUSE to detect these elusive systems.

scholarly journals Interactions among intermediate redshift galaxies

2020 ◽  
Vol 639 ◽  
pp. A30
Author(s):  
Persis Misquitta ◽  
Micah Bowles ◽  
Andreas Eckart ◽  
Madeleine Yttergren ◽  
Gerold Busch ◽  
...  
Keyword(s):  
Black Holes ◽  
Emission Line ◽  
Initial Conditions ◽  
Supermassive Black Holes ◽  
Emission Lines ◽  
Host Galaxies ◽  
The Galaxy ◽  
Line Features ◽  
The Masses ◽  
Narrow Emission

We present the properties of the central supermassive black holes and the host galaxies of the interacting object SDSS J134420.86+663717.8. We obtained optical long slit spectroscopy data from the Large Binocular Telescope using the Multi Object Double Spectrograph. Analysing the spectra revealed several strong broad and narrow emission lines of ionised gas in the nuclear region of one galaxy, whereas only narrow emission lines were visible for the second galaxy. The optical spectra were used to plot diagnostic diagrams, deduce rotation curves of the two galaxies, and calculate the masses of the central supermassive black holes. We find that the galaxy with broad emission line features has Seyfert 1 properties, while the galaxy with only narrow emission line features seems to be star-forming in nature. Furthermore, we find that the masses of the central supermassive black holes are almost equal at a few times 107 M⊙. Additionally, we present a simple N-body simulation to shed some light on the initial conditions of the progenitor galaxies. We find that for an almost orthogonal approach of the two interacting galaxies, the model resembles the optical image of the system.

scholarly journals 2.13. Optical and X-ray variability in NGC 4395

1998 ◽  
Vol 184 ◽  
pp. 83-84 ◽  
Author(s):  
P. Lira ◽  
A. Lawrence
Keyword(s):  
Emission Lines ◽  
X Ray ◽  
High Ionization ◽  
Ngc 4395 ◽  
Narrow Emission

The spectrum of the dwarf Seyfert 1 nucleus in NGC 4395 was first reported about a decade ago (Filippenko & Sargent 1989), showing high ionization narrow emission lines and broad permitted lines. The later detection of radio and X-ray compact nuclear sources and of a featureless UV continuum gave support to the idea that NGC 4395 is a genuine low luminosity AGN (Sramek 1992; Filippenko, Ho & Sargent 1993). However, it has been claimed that, unlike classic Seyferts, NGC 4395 does not vary at all (Shields & Filippenko 1992).

scholarly journals Outflowing Components in the Prototype Narrow-Line Seyfert 1 Galaxy Markarian 478

2004 ◽  
Vol 217 ◽  
pp. 364-365
Author(s):  
Qirong Yuan ◽  
Micheal Brotherton ◽  
Richard F. Green ◽  
Gerard A. Kriss
Keyword(s):  
Physical Condition ◽  
Peak Velocity ◽  
Emission Lines ◽  
Narrow Line ◽  
Velocity Shift ◽  
Outflow Velocity ◽  
Line Region ◽  
High Ionization ◽  
The Mean ◽  
Mean Time

Markarian 478 is the prototype narrow-line Seyfert 1 galaxy. Based on its spectra taken by the FUSE, HST/FOS, and Kitt Peak Observatory 2m Telescope, we find a tendency that the emission lines of increasing ionization level show increasing excess flux at their blue wings and an increasing line peak velocity shift. This may indicate an outflowing component in the Broad-Line Region (BLR) where the ionization level increases with ejection velocity. In the mean time, the associated absorption lines are present on the blue wings of the high-ionization emission doublet O VI λλ1032, 1038 and Lyman β line. The physical condition of some absorbing components can be well constrained with the assistance of photoionization models. The flux ratios at the blue wings of emission lines of various ionization levels, as a function of outflow velocity, could also put important constraints on the physical condition of the outflowing components.

scholarly journals The HST Sample of Radio-Loud Quasars: Fe II and Other Correlations

1997 ◽  
Vol 159 ◽  
pp. 106-107
Author(s):  
D. Wills ◽  
K.L. Thompson ◽  
M.S. Brotherton ◽  
Beverley J. Wills ◽  
J. A. Baldwin ◽  
...  
Keyword(s):  
Spectral Properties ◽  
Principal Component ◽  
Emission Lines ◽  
Narrow Line ◽  
X Ray ◽  
Narrow Component ◽  
Component Spectrum ◽  
The Mean ◽  
Jet Axis ◽  
Narrow Emission

We are analyzing the emission lines and continuum spectra of a sample of ~61 radio-loud quasars to investigate dependences amongst various spectral, radio, and X-ray parameters, in particular to look for dependences of spectral properties on inclination of the the radio-jet axis (Wills et al. 1997).We have carried out conventional correlation analyses, as well as spectral principal-component analyses (SPCA) as described in the previous paper (Wills et al. 1997). We found that the single largest contribution to the spectrum-tospectrum variations was from a component — the ‘first principal component’ (PC1) — that has a more UV (or less red) continuum than the mean spectrum, and a weaker narrow-line (NLR) spectrum. The ‘second principal component’ (PC2) accounts for only 8–12% of the spectrum-to-spectrum variation, contributing a weaker UV, and stronger red continuum, and showing stronger narrow emission lines. There is also a tendency for the broad (BLR) lines in the second principal component spectrum to be narrower (note the sharper He II λ1640 and [O III] λ1663 features redward of the stronger C IV λ1549 emission line, and perhaps a narrow component of the N V λ1240 line redward of Lyα).

scholarly journals Evidence for rapid disc formation and reprocessing in the X-ray bright tidal disruption event candidate AT 2018fyk

2019 ◽  
Vol 488 (4) ◽  
pp. 4816-4830 ◽  
Author(s):  
T Wevers ◽  
D R Pasham ◽  
S van Velzen ◽  
G Leloudas ◽  
S Schulze ◽  
...  
Keyword(s):  
Light Curve ◽  
Optical Spectra ◽  
Emission Lines ◽  
Tidal Disruption ◽  
X Ray ◽  
Physical Conditions ◽  
High Ionization ◽  
Optical Light Curve ◽  
Narrow Emission ◽  
Disruption Event

ABSTRACT We present optical spectroscopic and Swift UVOT/XRT observations of the X-ray and UV/optical bright tidal disruption event (TDE) candidate AT 2018fyk/ASASSN–18ul discovered by ASAS–SN. The Swift light curve is atypical for a TDE, entering a plateau after ∼40 d of decline from peak. After 80 d the UV/optical light curve breaks again to decline further, while the X-ray emission becomes brighter and harder. In addition to broad H, He, and potentially O/Fe lines, narrow emission lines emerge in the optical spectra during the plateau phase. We identify both high-ionization (O iii) and low-ionization (Fe ii) lines, which are visible for ∼45 d. We similarly identify Fe ii lines in optical spectra of ASASSN–15oi 330 d after discovery, indicating that a class of Fe-rich TDEs exists. The spectral similarity between AT 2018fyk, narrow-line Seyfert 1 galaxies, and some extreme coronal line emitters suggests that TDEs are capable of creating similar physical conditions in the nuclei of galaxies. The Fe ii lines can be associated with the formation of a compact accretion disc, as the emergence of low-ionization emission lines requires optically thick, high-density gas. Taken together with the plateau in X-ray and UV/optical luminosity this indicates that emission from the central source is efficiently reprocessed into UV/optical wavelengths. Such a two-component light curve is very similar to that seen in the TDE candidate ASASSN–15lh, and is a natural consequence of a relativistic orbital pericentre.

scholarly journals Impact of nuclear activity on extended emission line regions of nearby galaxies

1995 ◽  
Vol 149 ◽  
pp. 269-273
Author(s):  
E. Pécontal ◽  
P. Ferruit ◽  
A.S. Wilson
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies ◽  
Emission Lines ◽  
Nuclear Activity ◽  
Central Engine ◽  
Nearby Galaxies ◽  
The Impact ◽  
Integral Field ◽  
Extended Emission ◽  
Narrow Emission

AbstractWe used the integral field TIGER to map the intensity ratios of emission lines and the velocity field over the narrow emission line of a few nearby Seyfert galaxies. Our aim is to study the impact of nuclear activity on galaxies, which will hopefully help us to probe the central engine. We present here some results for two objects: M 51 and NGC 5929.

scholarly journals Characterizing Extreme Emission-line Galaxies. I. A Four-zone Ionization Model for Very High-ionization Emission*

2021 ◽  
Vol 922 (2) ◽  
pp. 170
Author(s):  
Danielle A. Berg ◽  
John Chisholm ◽  
Dawn K. Erb ◽  
Evan D. Skillman ◽  
Richard W. Pogge ◽  
...  
Keyword(s):  
Emission Line ◽  
High Energy ◽  
Emission Lines ◽  
Zone Model ◽  
Ionization Zone ◽  
Radiation Fields ◽  
High Ionization ◽  
Ionization Model ◽  
Emission Line Galaxies ◽  
Very High

Abstract Stellar population models produce radiation fields that ionize oxygen up to O+2, defining the limit of standard H ii region models (<54.9 eV). Yet, some extreme emission-line galaxies, or EELGs, have surprisingly strong emission originating from much higher ionization potentials. We present UV HST/COS and optical LBT/MODS spectra of two nearby EELGs that have very high-ionization emission lines (e.g., He ii λλ1640,4686 C iv λλ1548,1550, [Fe v]λ4227, [Ar iv]λλ4711,4740). We define a four-zone ionization model that is augmented by a very high-ionization zone, as characterized by He+2 (>54.4 eV). The four-zone model has little to no effect on the measured total nebular abundances, but does change the interpretation of other EELG properties: we measure steeper central ionization gradients; higher volume-averaged ionization parameters; and higher central T e , n e , and log U values. Traditional three-zone estimates of the ionization parameter can underestimate the average log U by up to 0.5 dex. Additionally, we find a model-independent dichotomy in the abundance patterns, where the α/H abundances are consistent but N/H, C/H, and Fe/H are relatively deficient, suggesting these EELGs are α/Fe-enriched by more than three times. However, there still is a high-energy ionizing photon production problem (HEIP3). Even for such α/Fe enrichment and very high log U s, photoionization models cannot reproduce the very high-ionization emission lines observed in EELGs.

scholarly journals ROSAT Selected Interacting Galaxies with Narrow Emission Lines

1994 ◽  
Vol 159 ◽  
pp. 372-372
Author(s):  
D. Engels ◽  
N. Bade ◽  
J. Studt ◽  
H. Fink
Keyword(s):  
Small Cluster ◽  
Emission Lines ◽  
Interacting Galaxies ◽  
Narrow Line ◽  
Hii Region ◽  
X Ray ◽  
Cluster Of Galaxies ◽  
Sky Survey ◽  
Objective Prism ◽  
Narrow Emission

In the context of an identification program of sources from the ROSAT All-Sky Survey (RASS) on Schmidt objective prism plates (Bade et al. 1992a, b) we discovered two galaxy pairs, which contain a narrow-line Seyfert 1 component with an X-ray luminosity of Lx ∼ 1044 erg s−1 and an HII–region galaxy. Apparently they are interacting. Their redshifts are 0.1 < z < 0.3 and their brightnesses 17.5 < B < 19.5. A third one was found among EINSTEIN sources. Typical separations between the components are 10″. Near the pairs other galaxies were found, and although their physical association is not confirmed spectroscopically it is quite probable that they form a small cluster of galaxies. ROSAT HRI observations indicate that the X-ray emission is not extended and originate from the AGN alone. It is remarkable that the AGN in all physical pairs identified so far have rather narrow permitted emission lines with linewidths ≤ 1500 km s−1.

scholarly journals Hypermassive black holes have faint broad and narrow emission lines

2020 ◽  
Vol 497 (3) ◽  
pp. 2992-3010
Author(s):  
Harshitha K Bhat ◽  
Susmita Chakravorty ◽  
Dhrubojyoti Sengupta ◽  
Martin Elvis ◽  
Sudeb Ranjan Datta ◽  
...  
Keyword(s):  
Black Holes ◽  
Extreme Ultraviolet ◽  
Selection Effect ◽  
Emission Lines ◽  
Ultraviolet Region ◽  
Baldwin Effect ◽  
Star Forming ◽  
Star Forming Regions ◽  
Accretion Rates ◽  
Narrow Emission

ABSTRACT The extreme ultraviolet region (EUV) provides most of the ionization that creates the high equivalent width (EW) broad and narrow emission lines (BELs and NELs) of quasars. Spectra of hypermassive Schwarzschild black holes (HMBHs; MBH ≥ 1010 M⊙) with α-discs, decline rapidly in the EUV suggesting much lower EWs. Model spectra for BHs of mass 106–1012 M⊙ and accretion rates 0.03 ≤ Lbol/LEdd ≤ 1.0 were input to the cloudy photoionization code. BELs become ∼100 times weaker in EW from MBH ∼ 108 M⊙ to MBH ∼ 1010 M⊙. The high-ionization BELs (O vi 1034 Å, C iv 1549 Å, and He ii 1640 Å) decline in EW from MBH ≥ 106 M⊙, reproducing the Baldwin effect, but regain EW for MBH ≥ 1010 M⊙. The low-ionization lines (Mg ii 2798 Å, H β 4861 Å, and H α 6563 Å) remain weak. Lines for maximally spinning HMBHs behave similarly. Line ratio diagrams for the BELs show that high O vi/H β and low C iv/H α may pick out HMBH, although O vi is often hard to observe. In NEL BPT diagrams, HMBHs lie among star-forming regions, except for highly spinning, high accretion rate HMBHs. In summary, the BELs expected from HMBHs would be hard to detect using the current optical facilities. From 100 to 1012 M⊙, the emission lines used to detect active galactic nuclei (AGNs) only have high EW in the 106–109 M⊙ window, where most AGNs are found. This selection effect may be distorting reported distributions of MBH.

Sign in / Sign up

Export Citation Format

Share Document