arXiv subjects

L. Feuillet

Publications and source records attributed to L. Feuillet.

4 recordsLinked to original sources

arXiv2025

Hot, Photoionized X-ray Gas in Two Luminous Type 2 Quasars: Chandra-HST Evidence for a Wind-Driven Sequence

We present new Chandra/ACIS-S imaging spectroscopy of two luminous type 2 quasars, FIRST J120041.4+314745 ($z$=0.116) and 2MASX J13003807+5454367 ($z$=0.088), and compare their X-ray emission with Hubble Space Telescope [O III]$\lambda$5007 morphologies and kinematics. Both systems show kiloparsec-scale soft X-ray emission. In FIRST J120041, the X-ray morphology is clumpy and closely follows the [O III] structures, with surface-brightness peaks co-spatial with the highest [O III] velocities (600-750 km s$^{-1}$) and broadest line widths ($\sim$1700 km s$^{-1}$). In 2MASX J130038, the X-ray emission is centrally concentrated and weakly correlated with rotational [O III] kinematics. Spectral modeling indicates that photoionization dominates the soft X-rays in both quasars. The inferred hot-gas reservoirs are substantial, $M_{\rm x-ray}\sim4.5\times10^{8}M_\odot$ (FIRST J120041) and $M_{\rm x-ray}\sim1.8\times10^{8}M_\odot$ (2MASX J130038), exceeding the outflowing [O III] masses by factors of $\sim$4 and $\sim$16. In 2MASX J130038, we identify a tentative blueshifted Fe XXVI Ly$\alpha$ line at $E_{\rm rest}=7.14\pm0.06$ keV ($v\sim7600$ km s$^{-1}$), consistent with a hot wind confined to the inner few hundred parsecs. Combining these results with a broader sample of twelve type 2 quasars, we argue that luminous quasars evolve along a continuous feedback sequence regulated by progressive clearing of circumnuclear gas. As AGN radiation and winds pierce the surrounding medium, systems transition from heavily enshrouded, compact configurations to phases where the X-ray and [O III] components strongly couple and, eventually, to energetically dominant outflows. FIRST J120041 and 2MASX J130038 represent two points along this sequence, tracing the emergence and growth of hot winds as primary drivers of quasar-scale feedback.

astro-ph.GA↗

arXiv2025

The X-ray Emission of NGC 5005: An Unobscured Low-Luminosity AGN with a Weakly Accreting Broad-Line Region

We present deep Chandra X-ray observations of NGC 5005, a LINER-dominated galaxy previously reported to host a broad H$\alpha$ emission line. The diffuse soft X-ray emission ($<$3 keV) extends out to $\sim$800 pc, while harder emission ($>$3 keV) is confined to the central $\sim$400 pc. Spatially resolved spectroscopy of the nuclear ($r<150$ pc) and extended ($150<r<500$ pc) regions reveals that these are best described by models including both photoionized and thermal plasma components, consistent with excitation by a low-luminosity AGN and shock-heated gas. Narrow-band imaging and excitation maps from the Hubble Space Telescope (HST) support this interpretation, closely matching the X-ray morphology and ionization structure. The detection of a faint hard X-ray nuclear source with Chandra, combined with stringent upper limits from NuSTAR and Swift, and consistency with the X-ray luminosity predicted from the HST [O III]$\lambda$5007 emission, indicates that NGC 5005 hosts an intrinsically low-luminosity ($L_{\rm bol} \sim 10^{41}$ erg s$^{-1}$), unobscured AGN. Despite the extremely low Eddington ratio inferred from our measurements ($\lambda_{\rm Edd} \sim 5 \times 10^{-6}$), the presence of a broad H$\alpha$ line in the optical spectrum suggests the persistence of a thin accretion disk, challenging standard paradigms of accretion flow configurations at such low accretion rates.

astro-ph.GA↗

arXiv2024

Hubble Space Telescope Observations of Nearby Type 1 Quasars. I. Characterisation of the Extended [O III] 5007{\AA} Emission

We use the Hubble Space Telescope to analyse the extended [O III] 5007A emission in seven bright radio-quiet type 1 quasars (QSO1s), focusing on the morphology and physical conditions of their extended Narrow-Line Regions (NLRs). We find NLRs extending 3-9 kpc, with four quasars showing roughly symmetrical structures (b/a=1.2-1.5) and three displaying asymmetric NLRs (b/a=2.4-5.6). When included with type 1 and type 2 AGNs from previous studies, the sizes of the extended [O III] regions scale with luminosity as $R[O III] \sim L[O III]^{0.5}$, consistent with photoionisation. However, when analysed separately, type 1s exhibit a steeper slope ($\gamma=0.57\pm0.05$) compared to type 2 AGNs ($\gamma=0.48\pm0.02$). We use photoionisation modeling to estimate the maximum NLRs sizes, assuming a minimum ionisation parameter of $\log(U) = -3$, an ionising luminosity based on the $L[O III]$-derived bolometric luminosity, and a minimum gas number density $n_H \sim 100\,\text{cm}^{-3}$, assuming that molecular clouds provide a reservoir for the ionised gas. The derived sizes agree well with direct measurements for a sample of type 2 quasars, but are underestimated for the current sample of QSO1s. A better agreement is obtained for the QSO1s using bolometric luminosities derived from the 5100A continuum luminosity. Radial mass profiles for the QSO1s show significant extended mass in all cases, but with less [O III]-emitting gas near the central AGN compared to QSO2s. This may suggest that the QSO1s are in a later evolutionary stage than QSO2s, further past the blow-out stage.

astro-ph.GA↗

arXiv2024

Resolving Dual Active Galactic Nuclei with ~100 pc separation in MCG-03-34-64

We report the serendipitous multiwavelength discovery of a candidate dual black hole system with a separation of ~100 pc, in the gas-rich luminous infrared galaxy MCG-03-34-64 (z=0.016). Hubble Space Telescope/ACS observations show three distinct optical centroids in the [O III] narrow-band and F814W images. Subsequent analysis of Chandra/ACIS data shows two spatially-resolved peaks of equal intensity in the neutral Fe Ka (6.2-6.6 keV) band, while high-resolution radio continuum observations with the Very Large Array at 8.46 GHz (3.6 cm band) show two spatially-coincident radio peaks. Fast shocks as the ionizing source seem unlikely, given the energies required for production of Fe Ka. If confirmed, the separation of ~100 pc would represent the closest dual AGN reported to date with spatially-resolved, multiwavelength observations.

astro-ph.GA↗