We have used optical Integral Field Spectroscopy in order to map the star formation history of the inner kiloparsec of the Post-Starburst Quasar (PSQ) J0330--0532 and to map its gas and stellar ...kinematics as well as the gas excitation. PSQs are hypothesized to represent a stage in the evolution of galaxies in which the star formation has been recently quenched due to the feedback of the nuclear activity, as suggested by the presence of the post-starburst population at the nucleus. We have found that the old stellar population (age \(\ge\) 2.5 Gyr) dominates the flux at 5100 \AA\ in the inner 0.26 kpc, while both the post-starburst (100 Myr \(\le\) age \(<\) 2.5 Gyr) and starburst (age \(<\) 100 Myr) components dominate the flux in a circumnuclear ring at \(\approx\)0.5 kpc from the nucleus. With our spatially resolved study we do not have found any post-starburst stellar population in the inner 0.26\,kpc. On the other hand, we do see the signature of AGN feedback in this region, which does not reach the circumnuclear ring where the post-starburst population is observed. We thus do not support the quenching scenario for the J0330-0532. In addition, we have concluded that the strong signature of the post-starburst population in larger aperture spectra (e.g. from Sloan Digital Sky Survey) is partially due to the combination of the young and old age components. Based on the M\(_{\rm BH}-\sigma_{\rm star}\) relationship and the stellar kinematics we have estimated a mass for the supermassive black hole of 1.48 \(\pm\) 0.66 \(\times\)10\(^7\) M\(_\odot\).
A&A 634, A114 (2020) The $M_{BH}$ - $\sigma_{\star}$ relation is considered a result of
co-evolution between the host galaxies and their super-massive black holes. For
elliptical-bulge hosting ...inactive galaxies, this relation is well established,
but there is still a debate whether active galaxies follow the same relation.
In this paper, we estimate black hole masses for a sample of 19 local luminous
AGNs (LLAMA) in order to test their location on the $M_{BH}$ - $\sigma_{\star}$
relation. Super-massive black hole masses ($M_{BH}$) were derived from the
broad-line based relations for H$\alpha$, H$\beta$ and Pa$\beta$ emission line
profiles for the Type 1 AGNs. We compare the bulge stellar velocity dispersion
($\sigma_{\star}$) as determined from the Ca II triplet (CaT) with the
dispersion measured from the near-infrared CO (2-0) absorption features for
each AGN and find them to be consistent with each other. We apply an extinction
correction to the observed broad line fluxes and we correct the stellar
velocity dispersion by an average rotation contribution as determined from
spatially resolved stellar kinematic maps. The H$\alpha$-based black hole
masses of our sample of AGNs were estimated in the range 6.34 $\leq$
$\log{M_{BH}}$ $\leq$ 7.75 M$_\odot$ and the $\sigma_{\star CaT}$ estimates
range between 73 $\leq$ $\sigma_{\star CaT}$ $\leq$ 227 km s$^{-1}$. From the
so-constructed $M_{BH}$ - $\sigma_{\star}$ relation for our Type 1 AGNs, we
estimate the black hole masses for the Type 2 AGNs and the inactive galaxies in
our sample. In conclusion, we find that our sample of local luminous AGNs is
consistent with the $M_{BH}$ - $\sigma_{\star}$ relation of lower luminosity
AGNs and inactive galaxies, after correcting for dust extinction and the
rotational contribution to the stellar velocity dispersion.
Galaxies grow through both internal and external processes. In about 10% of nearby red galaxies with little star formation, gas and stars are counter-rotating, demonstrating the importance of ...external gas acquisition in these galaxies. However, systematic studies of such phenomena in blue, star-forming galaxies are rare, leaving uncertain the role of external gas acquisition in driving evolution of blue galaxies. Based on new measurements with integral field spectroscopy of a large representative galaxy sample, we find an appreciable fraction of counter-rotators among blue galaxies (9 out of 489 galaxies). The central regions of blue counter-rotators show younger stellar populations and more intense, ongoing star formation than their outer parts, indicating ongoing growth of the central regions. The result offers observational evidence that the acquisition of external gas in blue galaxies is possible; the interaction with pre-existing gas funnels the gas into nuclear regions (< 1 kpc) to form new stars.
We present a spatially resolved stellar population study of the inner \(\sim\)200\,pc radius of NGC4303 based on near-infrared integral field spectroscopy with SINFONI/VLT at a spatial resolution of ...40-80pc and using the STARLIGHT code. We found the distribution of the stellar populations presents a spatial variation, suggesting an age stratification. Three main structures stand out. Two nuclear blobs, one composed by young stars (t \(\leq\) 50Myr) and one with intermediate-age stars (50Myr \(<\) t \(\leq\) 2Gyr) both shifted from the centre. The third one is an internal intermediate-age spiral arm-like structure, surrounding the blob of young stars. Our results indicate star formation has occurred through multiple bursts in this source. Furthermore, the youngest stellar populations (t \(\lesssim\) 2Gyr) are distributed along a circumnuclear star-forming ring with r\(\sim\)250pc. The ring displays star formation rates (SFRs) in the range of 0.002-0.14M\(_{\odot}\)yr\(^{-1}\), favoring the `pearls-on-a-string' scenario. The old underlying bulge stellar population component (t \(>\) 2Gyr) is distributed outside the two blob structures. For the nuclear region (inner \(\sim\)60pc radius) we derived a SFR of 0.43\,M\(_{\odot}\)yr\(^{-1}\) and found no signatures of non-thermal featureless continuum and hot dust emission, supporting the scenario in which a LLAGN/LINER-like source is hidden in the centre of NGC4303. Thus, our results reveal a rather complex star formation history in NGC4303, with different stellar population components coexisting with a low efficiency accreting black hole in its centre.
Feeding and Feedback in NGC3081 Schnorr-Müller, Allan; Storchi-Bergmann, Thaisa; Robinson, Andrew ...
arXiv.org,
01/2016
Paper, Journal Article
Odprti dostop
We present two-dimensional gaseous kinematics of the inner 1.2 \(\times\) 1.8 kpc\(^2\) of the Seyfert 2 galaxy NGC3081, from optical spectra (5600--7000Å) obtained with the GMOS integral field ...spectrograph on the Gemini North telescope at a spatial resolution of \(\approx\) 100pc. We have identified two-components in the line emitting gas. A narrower component (FWHM \(\approx\) 60-100km s\(^{-1}\)), which appears to be gas in the galaxy disk, and which shows a distorted rotation pattern, is observed over the whole field of view. A broader component (FWHM \(\approx\)150-250 km s\(^{-1}\)) is present in the inner \(\approx\) 2arcsec (200pc) and shows blueshifts and redshifts in the near and far sides of the galaxy, respectively, consistent with a bipolar outflow. Assuming this to be the case, we estimate that the mass outflow rate in ionized gas (\(\dot{M}_{out}\)) is between 1.9 \(\times 10^{-3}\)M\(_{\odot}\) yr\(^{-1}\) and 6.9 \(\times 10^{-3}\)M\(_{\odot}\) yr\(^{-1}\). The subtraction of a rotation model from the narrower component velocity field reveals a pattern of excess blueshifts of \(\approx\) 50km s\(^{-1}\) in the far side of the galaxy and similar excess redshifts in the near side, which are cospatial with a previously known nuclear bar. We interpret these residuals as due to gas following non-circular orbits in the barred potential. Under the assumption that these motions may lead to gas inflows, we estimate an upper limit for the mass inflow rate in ionized gas of \(\phi\) \(\approx\) 1.3 \(\times 10^{-2}\)M\(_{\odot}\) yr\(^{-1}\).
We perform an exploratory study of the physical properties of accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modeling the spectral energy distributions (SEDs) of 12 ...LLAGNs in low-ionization nuclear emission-line regions (LINERs). These SEDs we constructed from high-resolution radio, X-ray and optical/UV observations of the immediate vicinity of the black hole. We adopt a coupled accretion-jet model comprising an inner advection-dominated accretion flow (ADAF) and an outer standard thin disk. We present best-fit models in which either the ADAF or the jet dominate the X-ray emission. Six sources in our sample display an optical-UV excess with respect to ADAF and jet models; this excess can be explained as emission from the truncated disk with transition radii 30-225 Rs in four of them. In almost all sources the optical emission can also be attributed to unresolved, old stellar clusters with masses ~1E7-1E8 Msun. We find evidence for a correlation between the accretion rate and jet power and an anti-correlation between the radio-loudness and the accretion rate. We confirm previous findings that the radio emission is severely underpredicted by ADAF models and explained by the relativistic jet. We find evidence for a nonlinear relation between the X-ray and bolometric luminosities and a slight IR excess in the average model SED compared to that of quasars. We suggest that the hardness of the X-ray spectrum can be used to identify the X-ray emission mechanism and discuss directions for progress in understanding the origin of the X-rays.
We report the observation of an outflow perpendicular to the radio jet in near-infrared integral field spectra of the inner 250 pc of the Seyfert 2 galaxy NGC 5929. The observations were obtained ...with the Gemini Near infrared Integral Field Spectrograph at a spatial resolution of ~20 pc and spectral resolution R~5300 and reveal a region 50 pc wide crossing the nucleus and extending by 300 pc perpendicularly to the known radio jet in this galaxy. Along this structure - which we call SE-NW strip - the emission-line profiles show two velocity components, one blueshifted and the other redshifted by -150 km/s and 150 km/s, respectively, relative to the systemic velocity. We interpret these two components as due to an outflow perpendicular to the radio jet, what is supported by low frequency radio emission observed along the same region. We attribute this feature to the interaction of ambient gas with an "equatorial outflow" predicted in recent accretion disk and torus wind models. Perpendicularly to the SE-NW strip, thus approximately along the radio jet, single component profiles show blueshifts of ~-150 km/s to the north-east and similar redshifts to the south-west, which can be attributed to gas counter-rotating relative to the stellar kinematics. More double-peaked profiles are observed in association with the two radio hot-spots, attributed to interaction of the radio jet with surrounding gas.
Low-luminosity active galactic nuclei (LLAGNs) represent the bulk of the AGN population in the present-day universe and they trace the low-level accreting supermassive black holes. In order to probe ...the accretion and jet physical properties in LLAGNs as a class, we model the broadband radio to X-rays spectral energy distributions (SEDs) of 21 LLAGNs in low-ionization nuclear emission-line regions (LINERs) with a coupled accretion-jet model. The accretion flow is modeled as an inner ADAF outside of which there is a truncated standard thin disk. We find that the radio emission is severely underpredicted by ADAF models and is explained by the relativistic jet. The origin of the X-ray radiation in most sources can be explained by three distinct scenarios: the X-rays can be dominated by emission from the ADAF, or the jet, or the X-rays can arise from a jet-ADAF combination in which both components contribute to the emission with similar importance. For 3 objects both the jet and ADAF fit equally well the X-ray spectrum and can be the dominant source of X-rays whereas for 11 LLAGNs a jet-dominated model accounts better than the ADAF-dominated model for the data. The individual and average SED models that we computed can be useful for different studies of the nuclear emission of LLAGNs. From the model fits, we estimate important parameters of the central engine powering LLAGNs in LINERs, such as the mass accretion rate and the mass-loss rate in the jet and the jet power - relevant for studies of the kinetic feedback from jets.
We present the first results from the ongoing, intensive, multi-wavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this AGN was, in part, selected for its historically ...unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner broad line region partially covers the central source. Despite the obscuration, we measure UV and optical continuum reverberation lags consistent with a centrally illuminated Shakura-Sunyaev thin accretion disk, and measure reverberation lags associated with the optical broad line region, as expected. However, in the first 55 days of the campaign, when the obscuration was becoming most extreme, we observe a de-coupling of the UV continuum and the UV broad emission line variability. The correlation recovers in the next 42 days of the campaign, as Mrk 817 enters a less obscured state. The short CIV and Ly alpha lags suggest that the accretion disk extends beyond the UV broad line region.
We have mapped the stellar and gaseous kinematics, as well as the emission-line flux distributions and ratios, from the inner 450pc radius of Mrk1157, using 2D near-IR spectra obtained with the ...Gemini NIFS at a spatial resolution of 35pc. The stellar velocity field shows a rotation pattern, with a discrete S-shaped zero velocity curve. The presence of a bar is also supported by the residual map between the observed rotation field and a model of circular orbits in a Plummer potential. The stellar velocity dispersion map presents a partial ring of low-sigma values (50-60km/s) at 250pc from the nucleus surrounded by higher sigma values from the galaxy bulge, originated in kinematically colder regions with recent star formation. The velocity dispersion of the bulge (100km/s) implies in a black hole mass of 8.3x10^6M_Sun. Emission-line flux distributions are most extended along PA=27/153deg, reaching at least 450pc from the nucleus and following the orientation observed in previous optical emission-line OIII imaging and radio jet. The molecular H_2 emission is dominated by thermal processes, mainly due to X-ray heating by the active nucleus. The FeII excitation has a larger contribution from shocks produced by the radio jet, as evidenced by the line-ratio maps and velocity dispersion map, which show spatial correlation with the radio structures. The gaseous kinematics shows two components, one due to gas located in the galaxy plane and another in outflow, which is oriented close to the plane of the sky, thus extending to high latitudes, as the galaxy plane is inclined by 45deg relative to the plane of the sky. The gas rotating in the plane dominates the H_2 and Pa-beta emission, while the gas in outflow is observed predominantly in FeII emission. From the outflow velocities and implied geometry, we estimate an outflow mass rate of 6M_sun/yr for the ionised gas.
