arXiv subjects

E. Bertola

Publications and source records attributed to E. Bertola.

41 records · Page 3Linked to original sources

arXiv2024

The XMM-Newton and NuSTAR view of IRASF11119+3257. I Detection of multiple UFO components and a very cold corona

IRASF11119 is an ultra-luminous IR galaxy with post-merger morphology, hosting a type-1 QSO at z=0.189. Its 2013 Suzaku spectrum shows a prominent Ultra Fast Outflow (UFO) absorption feature (v_out~0.25c). In 2021, we obtained the first XMM-Newton long look of the target, coordinated with a simultaneous NuSTAR observation. The new high-quality data allow us to detect at P>99.8% c.l. multiple absorption features associated with the known UFO. Furthermore, an emission plus absorption feature at 1.1-1.3 keV reveals the presence of a blueshifted P-Cygni profile in the soft band. We associate the hard band features with blends of FeXXV and FeXXVI He$α$-Ly$α$ and He$β$-Ly$β$ line pairs and infer a large column (N$_H$~$10^{24}$ cm$^{-2}$) of highly ionized (log$ξ$~5) gas outflowing at v_out=0.27c. The 1 keV feature can be associated with a blend of Fe and Ne transitions, produced by a lower column (N$_H$~$10^{21}$ cm$^{-2}$) and ionization (log$ξ$~2.6) gas component outflowing at the same speed. Using a radiative-transfer disk wind model to fit the highly ionized UFO, we derive a large mass outflow rate, comparable with the mass accretion rate (M$_{out}$=4.25 M$_{Sun}$/yr, ~1.6 M$_{acc}$), and kinetic energy and momentum flux among the highest reported in the literature. We measure an extremely low high-energy cut-off (E$_c$~25 keV). Several other cases in the literature suggest that a steep X-ray continuum may be related to the formation of powerful winds. The lack of a significant momentum boost between the nuclear UFO and the different phases of the large-scale outflow, observed in IRASF11119 and in a growing number of sources with powerful UFOs, can be explained by (i) a momentum-driven expansion, (ii) an inefficient coupling of the UFO with the host ISM, or (iii) by repeated energy-driven expansion episodes with low duty-cycle, that average out on long time-scales.

astro-ph.HE↗

arXiv2024

Feedback and ionized gas outflows in four low-radio power AGN at z $\sim$0.15

An increasing number of observations and simulations suggests that low-power (<10$^{44}$ erg s$^{-1}$) jets may be a significant channel of feedback produced by active galactic nuclei (AGN), but little is known about their actual effect on their host galaxies from the observational point of view. We targeted four luminous type 2 AGN hosting moderately powerful radio emission ($\sim$10$^{44}$ erg s$^{-1}$), two of which and possibly a third are associated with jets, with optical integral field spectroscopy observations from the Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT) to analyze the properties of their ionized gas as well as the properties and effects of ionized outflows. We combined these observations with Very Large Array (VLA) and e-MERLIN data to investigate the relations and interactions between the radio jets and host galaxies. We detected ionized outflows as traced by the fast bulk motion of the gas. The outflows extended over kiloparsec scales in the direction of the jet, when present. In the two sources with resolved radio jets, we detected a strong enhancement in the emission-line velocity dispersion (up to 1000 km s$^{-1}$) perpendicular to the direction of the radio jets. We also found a correlation between the mass and the energetics of this high-velocity dispersion gas and the radio power, which supports the idea that the radio emission may cause the enhanced turbulence. This phenomenon, which is now being observed in an increasing number of objects, might represent an important channel for AGN feedback on galaxies.

astro-ph.GA↗

arXiv2024

Winds of change: the nuclear and galaxy-scale outflows and the X-ray variability of 2MASS 0918+2117

Powerful outflows from active galactic nuclei (AGN) can significantly impact the gas reservoirs of their host galaxies. However, it is still unclear how these outflows can propagate from the very central regions of galaxies to their outskirts, and whether nuclear winds can be driven by and/or be responsible for drastic spectral transitions. In this work we test feedback propagation models on the case test of 2MASS 0918+2117 (2M0918), a z=0.149 X-ray variable AGN, which showed tentative evidence for nuclear ultra-fast outflows (UFOs) in a 2005 XMM-Newton observation. We also investigate whether UFOs can be related to the observed X-ray variability. We observed 2M0918 with XMM-Newton and NuSTAR in 2020 to confirm the presence and characterize the UFOs. We perform a kinematic analysis of the 2005 SDSS optical spectrum to reveal and measure the properties of galaxy-scale ionized outflows. Furthermore, we construct 20-year-long lightcurves of observed flux, line-of-sight column density, and intrinsic accretion rate from the spectra of the first 4 SRG/eROSITA all-sky surveys and archival observations from Chandra and XMM-Newton.We significantly detect UFOs with v$\sim$0.16c and galaxy-scale ionized outflows with velocities of $\sim$ 700 km/s. We also find that the drastic X-ray variability (factors >10) can be explained both in terms of variable obscuration and variable intrinsic luminosity.Comparing the energetics of the two outflow phases, 2M0918 is consistent with momentum-driven wind propagation. 2M0918 expands the sample of AGN with both UFOs and ionized gas winds from 5 to 6, and brings the sample of AGN hosting multiscale outflows to 19, contributing to a clearer picture of feedback physics. From the variations in accretion rate, column density, and ionization level of the obscurer, we propose a scenario that connects obscurers, an accretion enhancement, and the emergence of UFOs

astro-ph.HE↗

arXiv2022

The properties of the X-ray corona in the distant ($z=3.91$) quasar APM 08279+5255

We present new joint XMM-Newton and NuSTAR observations of APM 08279+5255, a gravitationally-lensed, broad-absorption line quasar ($z=3.91$). After showing a fairly stable flux ($f_{\rm2-10}\simeq4-5.5\times10^{-13}\rm~erg~s^{-1}$) from 2000 to 2008, APM 08279+5255 was found in a fainter state in the latest X-ray exposures ($f_{\rm2-10}\simeq2.7\times10^{-13}\rm~erg~s^{-1}$), which can likely be ascribed to a lower X-ray activity. Moreover, the 2019 data present a prominent Fe K$α$ emission line and do not show any significant absorption line. This fainter state, coupled to the first hard X-ray sampling of APM 08279+5255, allowed us to measure X-ray reflection and the high-energy cutoff in this source for the first time. From the analysis of previous XMM-Newton and Chandra observations, X-ray reflection is demonstrated to be a long-lasting feature of this source, but less prominent prior to 2008, possibly due to a stronger primary emission. The estimated high-energy cutoff ($E_{\rm cut}=99_{-35}^{+91}$ keV) sets a new redshift record for the farthest ever measured and places APM 08279+5255 in the allowed region of the compactness-temperature diagram of X-ray coronae, in agreement with previous results on high-$z$ quasars.

astro-ph.HE↗

arXiv2020

X-raying winds in distant quasars: the first high-redshift wind duty cycle

Theoretical models of wind-driven feedback from Active Galactic Nuclei (AGN) often identify Ultra-fast outflows (UFOs) as being the main cause for generating galaxy-size outflows, possibly the main actors in establishing the so-called AGN-galaxy co-evolution. UFOs are well characterized in local AGN but much less is known in quasars at the cosmic time when SF and AGN activity peaked ($z\simeq1-3$). It is therefore mandatory to search for evidences of UFOs in high-$z$ sources to test the wind-driven AGN feedback models. Here we present a study of Q2237+030, the Einstein Cross, a quadruply-imaged radio-quiet lensed quasar located at $z=1.695$. We performed a systematic and comprehensive temporally and spatially resolved X-ray spectral analysis of all the available Chandra and XMM-Newton data (as of September 2019). We find clear evidence for spectral variability, possibly due to absorption column density (or covering fraction) variability intrinsic to the source. We detect, for the first time in this quasar, a fast X-ray wind outflowing at $v_{\rm out}\simeq0.1c$ that would be powerful enough ($\dot{E}_{\rm kin}\simeq0.1 L_{\rm bol}$) to significantly affect the host galaxy evolution. We report also on the possible presence of an even faster component of the wind ($v_{\rm out}\sim0.5c$). Given the large sample and long time interval spanned by the analyzed X-ray data, we are able to roughly estimate, for the first time in a high-$z$ quasar, the wind duty cycle as $\approx0.46\,(0.31)$ at $90\%\,(95\%)$ confidence level. Finally, we also confirm the presence of a Fe K$α$ emission line with variable energy, which we discuss in the light of microlensing effects as well as considering our findings on the source.

astro-ph.HE↗