scholarly journals Multiple AGN activity during the BCG assembly of XDCPJ0044.0-2033 at z ∼ 1.6

2020 ◽  
Vol 498 (2) ◽  
pp. 2719-2733
Author(s):  
A Travascio ◽  
A Bongiorno ◽  
P Tozzi ◽  
R Fassbender ◽  
F De Gasperin ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Elliptical Galaxy ◽  
Galactic Nuclei ◽  
Cluster Galaxy ◽  
X Ray ◽  
The Core ◽  
Galaxy Population

ABSTRACT Undisturbed galaxy clusters are characterized by a massive and large elliptical galaxy at their centre, i.e. the brightest cluster galaxy (BCG). How these central galaxies form is still debated. According to most models, a typical epoch for their assembly is $z$ ∼ 1–2. We have performed a detailed multiwavelength analysis of the core of XMM–Newton Distant Cluster Project (XDCP) J0044.0-2033 (XDCP0044), one of the most massive and densest galaxy clusters currently known at redshift $z$ ∼ 1.6, whose central galaxy population shows high star formation compared to lower z clusters and an X-ray active galactic nuclei (AGN) located close to its centre. SINFONI J-, H-, and KMOS YJ-, H-bands spectroscopic data have been analysed, together with deep archival HST photometric data in F105W, F140W, and F160W bands, Chandra X-ray, radio JVLA data at 1–2 GHz, and ALMA band-6 observations. In the very central region of the cluster (∼70 kpc × 70 kpc), two systems of interacting galaxies have been identified and studied (Complex A and B), with a total of seven confirmed cluster members. These galaxies show perturbed morphologies and three of them show signs of AGN activity. In particular, two type-1 AGN with typical broad lines have been found at the centre of each complex (both of them X-ray obscured and highly accreting with $\rm \lambda _{Edd}\sim 0.4-0.6$), while a type-2 AGN has been discovered in Complex A. The AGN at the centre of Complex B is also detected in X-ray, while the other two are spatially related to radio emission. The three AGN provide one of the closest AGN triple at $z$ > 1 revealed so far with a minimum (maximum) projected distance of 10 (40) kpc. The observation of high star formation, merger signatures, and nuclear activity in the core of XDCP0044 suggests that all these processes are key ingredients in shaping the nascent BCG. According to our data, XDCP0044 could form a typical massive galaxy of $M_{\star }\sim 10^{12} \, \mathrm{M}_{\odot }$, hosting a black hole of $\rm 2 \times 10^8\!-\!10^9 \, \mathrm{M}_{\odot }$, in a time-scale of the order of ∼2.5 Gyr.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals A 2.5-5 μm spectroscopic study of hard X-ray selected AGNs with AKARI

2013 ◽  
Vol 9 (S304) ◽  
pp. 66-67
Author(s):  
A. Castro ◽  
T. Miyaji ◽  
M. Shirahata ◽  
S. Oyabu ◽  
D. Clark ◽  
...  
Keyword(s):  
Star Formation ◽  
Neutral Hydrogen ◽  
Infrared Camera ◽  
X Ray ◽  
Star Formation Activity ◽  
Hydrogen Column Density ◽  
Polycyclic Aromatic ◽  
Low X

AbstractWe explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L14-195keV versus log L3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L14-195keV/MBH) versus log (L3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

scholarly journals The relationship between X-ray and optical absorbers in active galactic nuclei

2020 ◽  
Vol 493 (1) ◽  
pp. 930-939 ◽  
Author(s):  
Gunnar W Jaffarian ◽  
C Martin Gaskell
Keyword(s):  
Active Galactic Nuclei ◽  
Column Density ◽  
Scattered Light ◽  
Galactic Nuclei ◽  
Broad Line ◽  
Large Scatter ◽  
Standard Type ◽  
X Ray

ABSTRACT We present a large compilation of reddening estimates from broad-line Balmer decrements for active galactic nuclei (AGNs) with measured X-ray column densities. The median reddening is E(B − V) ≈ 0.77 ± 0.10 for type-1 to type-1.9 AGNs with reported column densities. This is notably higher than the median reddening of AGNs from the SDSS. We attribute this to the selection bias of the SDSS towards blue AGNs. For other AGNs, we find evidence of a publication bias against reporting low column densities. We find a significant correlation between NH and E(B − V) but with a large scatter of ±1 dex. On average, the X-ray columns are consistent with those predicted from E(B − V) for a solar neighbourhood dust-to-gas ratio. We argue that the large scatter of column densities and reddenings can be explained by X-ray column density variability. For AGNs with detectable broad-line regions (BLRs) that have undergone significant changes of Seyfert type (‘changing-look’ AGNs), we do not find any statistically significant differences in NH or E(B − V) compared to standard type-1 to type-1.9 AGNs. There is no evidence for any type-1 AGNs being Compton thick. We also analyse type-2 AGNs and find no significant correlation between NH and narrow-line region reddening. We find no evidence for a previously claimed anticorrelation. The median column density of LINERs is 22.68 ± 0.75 compared to a column density of 22.90 ± 0.28 for type-2 AGNs. We find the majority of low column density type-2 AGNs are LINERs, but NH is probably underestimated because of scattered light.

scholarly journals Evidence for obscured broad [O iii] components in Type-2 AGN

2021 ◽  
Vol 502 (2) ◽  
pp. 2508-2512
Author(s):  
Xue-Guang Zhang
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Unified Model ◽  
Sloan Digital Sky Survey ◽  
The Core ◽  
Large Samples ◽  
Sky Survey ◽  
Narrow Emission

ABSTRACT In the manuscript, we report evidence on broad [O iii] components apparently obscured in Type-2 active galactic nuclei (AGN) under the framework of the unified model, after checking properties of broad [O iii] emissions in large samples of Type-1 and Type-2 AGN in Sloan Digital Sky Survey DR12. We can well confirm the statistically lower flux ratios of the broad to the core [O iii] components in Type-2 AGN than in Type-1 AGN, which can be naturally explained by stronger obscured broad [O iii] components by central dust torus in Type-2 AGN, unless the unified model for AGN was not appropriate to the narrow emission lines. The results provide further evidence to support broad [O iii] components coming from emission regions nearer to central BHs, and also indicate the core [O iii] component as the better indicator for central activities in Type-2 AGN, due to few effects of obscuration on the core [O iii] component. Considering the broad [O iii] components as signs of central outflows, the results provide evidence for strong central outflows being preferentially obscured in Type-2 AGN. Furthermore, the obscured broad [O iii] component can be applied to explain the different flux ratios of [O iii]λ5007Å/H β between Type-1 and Type-2 AGN in the BPT diagram.

scholarly journals X-ray absorption in INTEGRAL active galactic nuclei

2020 ◽  
Vol 639 ◽  
pp. A5
Author(s):  
A. Malizia ◽  
L. Bassani ◽  
J. B. Stephen ◽  
A. Bazzano ◽  
P. Ubertini
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Axial Ratio ◽  
Host Galaxy ◽  
Host Galaxies ◽  
X Ray ◽  
Line Region ◽  
Absorbing Material

In this work the INTEGRAL hard X-ray selected sample of active galactic nuclei (AGN) has been used to investigate the possible contribution of absorbing material distributed within the host galaxies to the total amount of NH measured in the X-ray band. We collected all the available axial ratio measurements of the galaxies hosting our AGN together with their morphological information and found that for our hard X-ray selected sample as well there is a deficit of edge-on galaxies hosting type 1 AGN. We estimate that in our hard X-ray selected sample there is a deficit of 24% (±5%) of type 1 AGN. Possible bias in redshift has been excluded, as we found the same effect in a well-determined range of z where the number and the distributions of the two classes are statistically the same. Our findings clearly indicate that material located in the host galaxy on scales of hundreds of parsecs and not aligned with the putative absorbing torus of the AGN can contribute to the total amount of column density. This galactic absorber could be large enough to hide the broad line region of some type 1 AGN, thus causing their classification as type 2 objects and giving rise to the deficiency of type 1 objects in edge-on galaxies.

scholarly journals Dust reverberation mapping of type 2 AGN NGC 2110 realized with X-ray and 3–5 μm IR monitoring

2020 ◽  
Vol 495 (3) ◽  
pp. 2921-2929
Author(s):  
Hirofumi Noda ◽  
Taiki Kawamuro ◽  
Mitsuru Kokubo ◽  
Takeo Minezaki
Keyword(s):  
Time Lag ◽  
Galactic Nuclei ◽  
Light Curves ◽  
Time Lags ◽  
X Ray ◽  
Reverberation Mapping ◽  
Promising Tool ◽  
Best Fitting

ABSTRACT The dust reverberation mapping is one of powerful methods to investigate the structure of the dusty tori in active galactic nuclei (AGNs), and it has been performed on more than a hundred type 1 AGNs. However, no clear results have been reported on type 2 AGNs because their strong optical/UV extinction completely hides their accretion disc emission. Here, we focus on an X-ray-bright type 2 AGN, NGC 2110, and utilize 2–20 keV X-ray variation monitored by MAXI to trace disc emission, instead of optical/UV variation. Comparing it with light curves in the WISE infrared (IR) W1 band ($\lambda =3.4~\mu$m) and W2 band ($\lambda =4.6~\mu$m) with cross-correlation analyses, we found candidates of the dust reverberation time lag at ∼60, ∼130, and ∼1250 d between the X-ray flux variation and those of the IR bands. By examining the best-fitting X-ray and IR light curves with the derived time lags, we found that the time lag of ∼130 d is most favoured. With this time lag, the relation between the time lag and luminosity of NGC 2110 is consistent with those in type 1 AGNs, suggesting that the dust reverberation in NGC 2110 mainly originates in hot dust in the torus innermost region, the same as in type 1 AGNs. As demonstrated by the present study, X-ray and IR simultaneous monitoring can be a promising tool to perform the dust reverberation mapping on type 2 AGNs.

scholarly journals A joint SZ–X-ray–optical analysis of the dynamical state of 288 massive galaxy clusters

2020 ◽  
Vol 495 (1) ◽  
pp. 705-725 ◽  
Author(s):  
A Zenteno ◽  
D Hernández-Lang ◽  
M Klein ◽  
C Vergara Cervantes ◽  
D L Hollowood ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
High Redshift ◽  
Peak Position ◽  
Cluster Galaxy ◽  
X Ray ◽  
Dynamical State ◽  
Dark Energy Survey ◽  
The Galaxy ◽  
Merger Rate ◽  
Galaxy Population

ABSTRACT We use imaging from the first three years of the Dark Energy Survey to characterize the dynamical state of 288 galaxy clusters at 0.1 ≲ z ≲ 0.9 detected in the South Pole Telescope (SPT) Sunyaev–Zeldovich (SZ) effect survey (SPT-SZ). We examine spatial offsets between the position of the brightest cluster galaxy (BCG) and the centre of the gas distribution as traced by the SPT-SZ centroid and by the X-ray centroid/peak position from Chandra and XMM data. We show that the radial distribution of offsets provides no evidence that SPT SZ-selected cluster samples include a higher fraction of mergers than X-ray-selected cluster samples. We use the offsets to classify the dynamical state of the clusters, selecting the 43 most disturbed clusters, with half of those at z ≳ 0.5, a region seldom explored previously. We find that Schechter function fits to the galaxy population in disturbed clusters and relaxed clusters differ at z > 0.55 but not at lower redshifts. Disturbed clusters at z > 0.55 have steeper faint-end slopes and brighter characteristic magnitudes. Within the same redshift range, we find that the BCGs in relaxed clusters tend to be brighter than the BCGs in disturbed samples, while in agreement in the lower redshift bin. Possible explanations includes a higher merger rate, and a more efficient dynamical friction at high redshift. The red-sequence population is less affected by the cluster dynamical state than the general galaxy population.

scholarly journals Reconciling galaxy cluster shapes, measured by theorists versus observers

2020 ◽  
Vol 500 (2) ◽  
pp. 2627-2644
Author(s):  
David Harvey ◽  
Andrew Robertson ◽  
Sut-Ieng Tam ◽  
Mathilde Jauzac ◽  
Richard Massey ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Orientation Angle ◽  
Galaxy Cluster ◽  
Galactic Nuclei ◽  
Weak Lensing ◽  
Strongly Correlated ◽  
The Bahamas ◽  
Cluster Galaxy ◽  
Moments Of Inertia ◽  
X Ray

ABSTRACT If properly calibrated, the shapes of galaxy clusters can be used to investigate many physical processes: from feedback and quenching of star formation, to the nature of dark matter. Theorists frequently measure shapes using moments of inertia of simulated particles’. We instead create mock (optical, X-ray, strong-, and weak-lensing) observations of the 22 most massive ($\sim 10^{14.7}\, \mathrm{ M}_\odot$) relaxed clusters in the BAHAMAS simulations. We find that observable measures of shape are rounder. Even when moments of inertia are projected into 2D and evaluated at matched radius, they overestimate ellipticity by 56 per cent (compared to observable strong lensing) and 430 per cent (compared to observable weak lensing). Therefore, we propose matchable quantities and test them using observations of eight relaxed clusters from the Hubble Space Telescope (HST) and Chandra X-Ray Observatory. We also release our HST data reduction and lensing analysis software to the community. In real clusters, the ellipticity and orientation angle at all radii are strongly correlated. In simulated clusters, the ellipticity of inner (<rvir/20) regions becomes decoupled: for example, with greater misalignment of the central cluster galaxy. This may indicate overly efficient implementation of feedback from active galactic nuclei. Future exploitation of cluster shapes as a function of radii will require better understanding of core baryonic processes. Exploitation of shapes on any scale will require calibration on simulations extended all the way to mock observations.

AGN1 vs AGN2 dichotomy as seen from the point of view of ionized outflows

2019 ◽  
Vol 15 (S356) ◽  
pp. 96-96
Author(s):  
Eleonora Sani
Keyword(s):  
Accretion Rate ◽  
Point Of View ◽  
Emission Lines ◽  
Black Hole Mass ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Wide Range ◽  
Strong Contrast

AbstractI present a detailed study of ionized outflows in a large sample of 650 hard X-ray detected AGN. Taking advantage of the legacy value of the BAT AGN Spectroscopic Survey (BASS, DR1), we are able to reveal the faintest wings of the [OIII] emission lines associated with outflows. The sample allows us to derive the incidence of outflows covering a wide range of AGN bolometric luminosity and test how the outflow parameters are related with various AGN power tracers, such as black hole mass, Eddington ratio, luminosity. I’ll show how ionized outflows are more frequently found in type 1.9 and type 1 AGN (50% and 40%) with respect to the low fraction in type 2 AGN (20%). Within such a framework, I’ll demonstrate how type 2 AGN outflows are almost evenly balanced between blue- and red-shifted winds. This, in strong contrast with type 1 and type 1.9 AGN outflows which are almost exclusively blue-shifted. Finally, I’ll prove how the outflow occurrence is driven by the accretion rate, whereas the dependence of outflow properties with respect to the other AGN power tracers happens to be quite mild.

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