The XDSPRES CL-based package for reducing OSIRIS cross-dispersed spectra

We present a description of the CL-based package XDSPRES, which aims at being a complete reducing facility for cross-dispersed spectra taken with the Ohio State Infrared Imager/Spectrometer, as installed at the SOAR telescope. This instrument provides spectra in the range between 1.2um and 2.35um in a single exposure, with resolving power of R ~ 1200. XDSPRES consists of two tasks, namely xdflat and doosiris. The former is a completely automated code for preparing normalized flat field images from raw flat field exposures. Doosiris was designed to be a complete reduction pipeline, requiring a minimum of user interaction. General steps towards a fully reduced spectrum are explained, as well as the approach adopted by our code. The software is available to the community through the web site http://www.if.ufrgs.br/~ruschel/software.Comment: 14 pages, 10 figure

Probing the active galactic nucleus unified model torus properties in Seyfert galaxies

We studied the physical parameters of a sample comprising of all Spitzer/Infrared Spectrograph public spectra of Seyfert galaxies in the mid-infrared (5.2–38 μm range) under the active galactic nucleus (AGN) unified model. We compare the observed spectra with ∼106 CLUMPY model spectral energy distributions, which consider a torus composed of dusty clouds. We find a slight difference in the distribution of line-of-sight inclination angle, i, requiring larger angles for Seyfert 2 (Sy 2) and a broader distribution for Seyfert 1 (Sy 1). We found small differences in the torus angular width, σ, indicating that Sy 1may host a slightly narrower torus than Sy 2. The torus thickness, together with the bolometric luminosities derived, suggests a very compact torus up to ∼6 pc from the central AGN. The number of clouds along the equatorial plane, N, as well the index of the radial profile, q, is nearly the same for both types. These results imply that the torus cloud distribution is nearly the same for type 1 and type 2 objects. The torus mass is almost the same for both types of activity, with values in the range of Mtor ∼ 104−107M . The main difference appears to be related to the clouds’ intrinsic properties: type 2 sources present higher optical depths τ V. The results presented here reinforce the suggestion that the classification of a galaxy may also depend on the intrinsic properties of the torus clouds rather than simply on their inclination. This is in contradiction with the simple geometric idea of the unification model

The metal-poor dwarf irregular galaxy candidate next to Mrk 1172

In this work we characterise the properties of the object SDSS J020536.84-081424.7, an extended nebular region with projected extension of $14 \times 14$ kpc$^{2}$ in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 ($1 \times 10^{11} M_{\odot}$) and our object of study ($3 \times 10^{9} M_{\odot}$). While the stellar content of Mrk 1172 is dominated by an old ($\sim 10$ Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from $\sim 100$ Myr to $\sim 1$ Gyr) and presents strong emission lines such as: H${\beta}$, [O III] ${\lambda}{\lambda}$4959,5007, H${\alpha}$, [N II] ${\lambda}{\lambda}$6549,6585 and [S II] ${\lambda}{\lambda}$6717,6732. Using these emission lines we find that it is metal-poor (with $Z \sim$ 1/3 $Z_{\odot}$, comparable to the LMC) and is actively forming stars ($0.70$ M$_{\odot}$ yr$^{-1}$), especially in a few bright clumpy knots that are readily visible in H${\alpha}$. The object has an ionised gas mass $\geq 3.8 \times 10^{5}$ M$_{\odot}$. Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disk and is being affected by interaction with Mrk 1172. We conclude that SDSS J020536.84-081424.7 is most likely a dwarf irregular galaxy (dIGal)

The metal-poor dwarf irregular galaxy candidate next to Mrk 1172

In this work, we characterize the properties of the object SDSS J020536.84−081424.7, an extended nebular region with projected extension of 14 × 14 kpc2 in the line of sight of the ETG Mrk 1172, using unprecedented spectroscopic data from MUSE. We perform a spatially resolved stellar population synthesis and estimate the stellar mass for both Mrk 1172 (1 × 1011 M ) and our object of study (3 × 109 M ). While the stellar content of Mrk 1172 is dominated by an old (∼10 Gyr) stellar population, the extended nebular emission has its light dominated by young to intermediate age populations (from ∼100 Myr to ∼1 Gyr) and presents strong emission lines such as H β; [O III] λλ4959, 5007 Å; H α; [N II] λλ6549, 6585 Å; and [S II] λλ6717, 6732 Å. Using these emission lines, we find that it is metal poor (with Z ∼ 1/3 Z , comparable to the LMC) and is actively forming stars (0.70 M yr−1), especially in a few bright clumpy knots that are readily visible in H α. The object has an ionized gas mass ≥3.8 × 105 M . Moreover, the motion of the gas is well described by a gas in circular orbit in the plane of a disc and is being affected by interaction wtih Mrk 1172. We conclude that SDSS J020536.84−081424.7 is most likely a dwarf irregular galaxy (the dIGal)

Exploring the AGN-Merger Connection in Arp 245 I: Nuclear Star Formation and Gas Outflow in NGC 2992

Galaxy mergers are central to our understanding of galaxy formation, especially within the context of hierarchical models. Besides having a large impact on the star formation history, mergers are also able to influence gas motions at the centre of galaxies and trigger an Active Galactic Nucleus (AGN). In this paper, we present a case study of the Seyfert galaxy NGC 2992, which together with NGC 2993 forms the early-stage merger system Arp 245. Using Gemini Multi-Object Spectrograph (GMOS) integral field unit (IFU) data from the inner 1.1 kpc of the galaxy we were able to spatially resolve the stellar populations, the ionisation mechanism and kinematics of ionised gas. From full spectral synthesis, we found that the stellar population is primarily composed by old metal-rich stars (t $\geq$ 1.4 Gyr, $Z \geq 2.0$\zsun), with a contribution of at most 30 per cent of the light from a young and metal-poor population (t $\leq$ 100 Myr, $Z \leq 1.0$\zsun). We detect \halpha and \hbeta emission from the Broad Line Region (BLR) with a Full Width at Half Maximum (FWHM) of $\sim$ 2000\kms. The Narrow Line Region (NLR) kinematics presents two main components: one from gas orbiting the galaxy disk and a blueshifted (velocity $\approx$ -200\kms) outflow, possibly correlated with the radio emission, with mass outflow rate of $\sim$ 2 M$_{\odot}$ yr$^{-1}$ and a kinematic power of $\sim$ 2 $\times 10^{40}$ erg s$^{-1}$ (\Eout/\Lbol $\approx$ 0.2 per cent). We also show even though the main ionisation mechanism is the AGN radiation, ionisation by young stars and shocks may also contribute to the emission line ratios presented in the innermost region of the galaxy.Comment: 20 pages, 13 Figs, Accepted for publication to the MNRA

Gauging the effect of supermassive black holes feedback on quasar host galaxies

In order to gauge the role that active galactic nuclei play in the evolution of galaxies via the effect of kinetic feedback in nearby QSO 2’s (z ∼ 0.3), we observed eight such objects with bolometric luminosities Lbol∼1046ergs−1 using Gemini Multi-Object Spectrograph-integral field units. The emission lines were fitted with at least two Gaussian curves, the broadest of which we attributed to gas kinetically disturbed by an outflow. We found that the maximum extent of the outflow ranges from ∼1 to 8 kpc, being ∼0.5±0.3 times the extent of the [OIII] ionized gas region. Our ‘default’ assumptions for the gas density (obtained from the [SII] doublet) and outflow velocities resulted in peak mass outflow rates of M˙defout∼ 3–30 M⊙yr−1 and outflow power of E˙defout∼1041–1043ergs−1⁠. The corresponding kinetic coupling efficiencies are εdeff=E˙defout/Lbol∼7×10−4–0.5 per cent, with the average efficiency being only 0.06 per cent (0.01 per cent median), implying little feedback powers from ionized gas outflows in the host galaxies. We investigated the effects of varying assumptions and calculations on M˙out and E˙out regarding the ionized gas densities, velocities, masses, and inclinations of the outflow relative to the plane of the sky, resulting in average uncertainties of 1 dex. In particular, we found that better indicators of the [OIII] emitting gas density than the default [SII] line ratio, such as the [ArIV] λλ4711,40 line ratio, result in almost an order of magnitude decrease in the εf

The Eddington ratio-dependent ‘changing look’ events in NGC 2992

We present an analysis of historical multiwavelength emission of the `Changing Look’ (CL) Active Galactic Nucleu (AGN) in NGC 2992, covering epochs ranging from 1978 to 2021, as well as new X-ray and optical spectra. The galaxy presents multiple Seyfert type transitions from Type 2 to intermediate-type, losing and regaining its Hα broad emission lines (BEL) recurrently. In X-rays, the source shows intrinsic variability with the absorption corrected luminosity varying by a factor of ∼ 40. We rule-out tidal disruption events or variable obscuration as causes of the type transitions, and show that the presence and the flux of th Hα BEL is directly correlated with the 2–10 keV X-ray luminosity (L2−10): the component disappears at L2−10 ≤ 2.6 × 1042 erg cm−2 s−1; this luminosity value translates into an Eddington ratio (λEdd) of ∼ 1 per cent. The λEdd in which the BEL transitions occur is the same as the critical value at which a state transition between a radiatively inefficient accretion flow and a thin accretion disk is expected, such similarity suggests that the AGN is operating at the threshold mass accretion rate between the two accretion modes. We find a correlation between the narrow Fe Kα flux and λEdd, and an anticorrelation between full-width at half maximum of Hα BEL and λEdd, in agreement with theoretical predictions. Two possible scenarios for type transitions are compatible with our results: either the dimming of the AGN continuum, which reduces the supply of ionizing photons available to excite the gas in the Broad Line Region (BLR), or the fading of the BLR structure itself occurs as the low accretion rate is not able to sustain the required cloud flow rate in a disc-wind BLR model

AGNIFS survey of local AGN : GMOS-IFU data and outflows in 30 sources

We analyse optical data cubes of the inner kiloparsec of 30 local (z ≤ 0.02) active galactic nucleus (AGN) hosts that our research group, AGNIFS, has collected over the past decade via observations with the integral field units of the Gemini Multi-Object Spectrographs. Spatial resolutions range between 50 and 300 pc and spectral coverage is from 4800 or 5600 to 7000 Å, at velocity resolutions of ≈50 km s−1. We derive maps of the gas excitation and kinematics, and determine the AGN ionization axis – which has random orientation relative to the galaxy – and the kinematic major axes of the emitting gas. We find that rotation dominates the gas kinematics in most cases, but is disturbed by the presence of inflows and outflows. Outflows have been found in 21 nuclei, usually along the ionization axis. The gas velocity dispersion is traced by W80 (velocity width encompassing 80 per cent of the line flux), adopted as a tracer of outflows. In seven sources, W80 is enhanced perpendicularly to the ionization axis, indicating lateral expansion of the outflow. We have estimated mass-outflow rates M˙ and powers E˙, finding median values of log [M/˙ ( M yr−1)] = −2.1+1.6 −1.0 and log [E/˙ ( erg s−1)] = 38.5+1.8 −0.9, respectively. Both quantities show a mild correlation with the AGN luminosity (LAGN). E˙ is of the order of 0.01 LAGN for four sources, but much lower for the majority (nine) of the sources, with a median value of log [E/L AGN] = −5.34+3.2 −0.9, indicating that typical outflows in the local Universe are unlikely to significantly impact their host galaxy evolution