Multi-phase AGN-driven outflow in the NLSy1 IRAS 17020+4544. Unveiling dual-feedback and an energy-conserving ionized outflow with MEGARA/GTC integral field spectroscopy

Abstract

The narrow-line Seyfert 1 (NLSy1) galaxy IRAS~17020+4544 is one of the few known sources exhibiting a multi-phase outflow detected in both highly ionized and molecular gas, consistent with AGN feedback operating in an `energy-conserving' regime. We investigate the properties and kinematics of the warm ionized gas using new optical seeing-limited integral-field spectroscopic observations obtained with MEGARA at the Gran Telescopio Canarias in both low- (R$\sim$6000) and medium-resolution (R$\sim$12000) modes. The H$α$ and [OIII]$λ$5007 emission lines are modeled with multi-Gaussian fitting to characterize the ionized gas kinematics and derive the energetics of the outflow, which we compare with those of the X-ray and molecular phases. Ionization diagnostic diagrams (WHAN, WHaD, and BPT) are used to investigate the dominant ionization mechanism. We detect a fast ionized outflow traced by both H$α$ and [OIII] emission lines, with similar spatial extensions (R$_\mathrm{out}\sim$1 kpc and $\sim$0.5 kpc) and velocities (v$_\mathrm{out}\sim$1460 and 1240 km s$^{-1}$, respectively), as well as a slower ionized outflow (v$_\mathrm{out}\sim$450 km s$^{-1}$) detected in the secondary component of the [OIII] line. The fast outflow follows an `energy-conserving' regime, while the slower component is consistent with a `momentum-driven' regime. The ionized outflows are enclosed within the molecular outflow detected with NOEMA (R$_\mathrm{CO}$=2.8$\pm$0.3 kpc), and the large momentum boosts derived in both phases suggest efficient AGN feedback, likely dominated by radiatively driven winds (quasar-mode) rather than kinetic (jet-driven) processes. Ionization diagnostics suggest that the outflow is mainly AGN-driven, with potential contributions from star formation and shocks. The molecular outflow dominates, with the ionized phase contributing less to the mass and feedback efficiency.

Figures (22)

• Figure 1: Observed integrated spectrum of the inner region (R $\sim$ 1.9 kpc $\approx$ 1.6$^{\prime\prime}$) obtained with the LR-R setup. Several emission lines are detected, including the prominent H$\alpha$-[NII] complex, the fainter [SII] and [OI] doublets, as well as very faint [FeVII], FeII and HeI lines.
• Figure 2: Top: SDSS-r continuum image of IRAS17. The MEGARA-IFU FoV is indicated by a black rectangle. A foreground star (marked with a black star) is visible to the north along with the companion galaxy (indicated by a magenta square) detected by Salome21. The flux intensity map is shown in nanomaggy units (1 nanomaggy = 3.631 $\mu$Jy). Bottom: Continuum image obtained with MEGARA-IFU within the wavelength range 6770-6840 Å. The flux intensity map is shown in Jy. North is up and east is to the left in both images. The continuum peak emission is marked with a black cross in both panels and corresponds to the AGN position, as supported by its coincidence with the optical AGN position measured by Gaia, the radio emission detected with e-MERLIN at 1.5 GHz (Longinotti23), and the CO peak emission (Salome21).
• Figure 3: Nuclear integrated spectra (within the PSF region) of the H$\alpha$-[NII]$\lambda\lambda$6548,6583 ( top panel) and H$\beta$-[OIII]$\lambda\lambda$4959,5007 complexes ( bottom panel), fitted with three kinematic components. For the Balmer lines, the green, magenta, and blue curves represent the systemic, ILR, and broad (outflowing) components, respectively. For the [OIII] lines, the green, purple, and blue curves represent the systemic, intermediate (slow outflow), and broad (fast outflow) components.
• Figure 4: FeII template subtraction from the observed H$\beta$-[OIII] complex at the position of the emission peak in the MR-G setup (within a single spaxel of 0.4$^{\prime\prime}$$\times$0.4$^{\prime\prime}$). The observed spectrum is shown in light blue, the FeII template in orange, and the residuals (pure H$\beta$-[OIII] complex) in green. The red dashed vertical lines mark the iron emission lines in this wavelength range (i.e., rest-frame wavelengths: $\lambda_{\mathrm{Fe\,II}} = 4923.92$, 4993.35, and 5018.45 Å).
• Figure 5: H$\alpha$ flux map of the primary component (red contours), with overlaid $^{12}$CO(1-0) contours of the systemic emission (white) from Salome21. The molecular and ionized gas in IRAS17 and its companion galaxy, traced on the north-west side by the CO contours, exhibit a remarkable spatial overlap.