Warm molecular and ionized gas kinematics in the type-2 quasar J0945+1737

¹ Instituto de Astrofísica de Canarias, Calle Vía Láctea, s/n, 38205 La Laguna, Tenerife, Spain
e-mail: giovanna.speranza@iac.es
² Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
³ Departamento de Física, CCNE, Universidade Federal de Santa Maria, Santa Maria, 97105-900 RS, Brazil
⁴ Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK
⁵ Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
⁶ Laboratorio Nacional de Astrofisica, R. dos Estados Unidos, 37504-364 Itajub, MG, Brazil
⁷ Instituto Nacional de Pesquisas Espaciais, Av. dos Astronautas, 12227-010 So Jos dos Campos, SP, Brazil
⁸ Dipartimento di Fisica e Astronomia “Augusto Righi”, Università di Bologna, via Gobetti 93/2, 40129 Bologna, Italy
⁹ INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, via Gobetti 93/3, 40129 Bologna, Italy
¹⁰ Centre for Extragalactic Astronomy, Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
¹¹ SISSA, Via Bonomea 265, 34136 Trieste, Italy
¹² Department of Physics and Astronomy, University of Southampton, Highfield SO17 1BJ, UK
¹³ University of Bath, Department of Physics, Claverton Down, Bath BA2 7AY, UK

Received: 18 March 2022
Accepted: 28 June 2022

Abstract

We analyse Near-Infrared Integral Field Spectrograph (NIFS) observations of the type-2 quasar (QSO2) SDSS J094521.33+173753.2 to investigate its warm molecular and ionized gas kinematics. This QSO2 has a bolometric luminosity of 10^45.7 erg s⁻¹ and a redshift of z = 0.128. The K-band spectra provided by NIFS cover a range of 1.99–2.40 μm where low ionization (Paα and Brδ), high ionization ([S XI]λ1.920 μm and [Si VI]λ1.963 μm), and warm molecular lines (from H₂1-0S(5) to 1-0S(1)) are detected, allowing us to study the multi-phase gas kinematics. Our analysis reveals gas in ordinary rotation in all the emission lines detected and also outflowing gas in the case of the low and high ionization emission lines. In the case of the nuclear spectrum, which corresponds to a circular aperture of 0.3″ (686 pc) in diameter, the warm molecular lines can be characterized using a single Gaussian component of full width at half maximum (FWHM) = 350 − 400 km s⁻¹, while Paα, Brδ, and [Si VI] are best fitted with two blue-shifted Gaussian components of FWHM ∼ 800 and 1700 km s⁻¹, in addition to a narrow component of ∼300 km s⁻¹. We interpret the blue-shifted broad components as outflowing gas, which reaches the highest velocities, of up to −840 km s⁻¹, in the south-east direction (PA ∼ 125°), extending up to a distance of ∼3.4 kpc from the nucleus. The ionized outflow has a maximum mass outflow rate of Ṁ_out,max = 42–51 M_⊙ yr⁻¹, and its kinetic power represents 0.1% of the quasar bolometric luminosity. Very Large Array (VLA) data of J0945 show extended radio emission (PA ∼ 100°) that is aligned with the clumpy emission traced by the narrow component of the ionized lines up to scales of several kiloparsecs, and with the innermost part of the outflow (central ∼0.4″ = 915 pc). Beyond that radius, at the edge of the radio jet, the high velocity gas shows a different PA of ∼125°. This might be an indication that the line-emitting gas is being compressed and accelerated by the shocks generated by the radio jet.