Near-infrared Integral Field Spectrograph Research Articles

Bayesian calibration of quasi-static field distortions in HARMONI

ABSTRACT The high angular resolution monolithic optical and near-infrared Integral field spectrograph is the first light visible and near-infrared integral field spectrograph for the Extremely Large Telescope. To reach the diffraction limit of the telescope (≈ 10 mas) and maintain an optimal image quality over long exposures, an accurate measurement of geometrical distortions in the instrument’s guide star field is needed. Geometrical distortions affecting the guide stars map directly to pointing errors of the science field. The systematic contribution to the pointing error can be calibrated and removed by a corrective model. In this work, we propose a formulation of the corrective model that aims to calibrate the geometrical field distortions down to a given target residual, as well as reducing the time spent in calibrations. We also propose a calibration procedure that accounts for the uncertainties of the measurement process. We developed a tool named harmoni-pm to simulate the expected pointing error caused by geometrical distortions and validate the effectiveness of the proposed corrective model. We also relied on pseudo Zernike polynomials to formulate the model, and the Bayesian theoretical framework to study the propagation of uncertainties along the calibration process. Compared with the classical calibration algorithm, the Bayesian calibration algorithm was able to reduce the number of calibration points required to reach the same model residual. Additionally, we were able to optimize the hardware of the Geometrical Calibration Unit and reduce the time required to achieve the calibration goal.

Detecting Biosignatures in Nearby Rocky Exoplanets Using High-contrast Imaging and Medium-resolution Spectroscopy with the Extremely Large Telescope

In the upcoming decades, one of the primary objectives in exoplanet science is to search for habitable planets and signs of extraterrestrial life in the Universe. Signs of life can be indicated by thermal-dynamical imbalance in terrestrial planet atmospheres. O2 and CH4 in the modern Earth’s atmosphere are such signs, commonly termed biosignatures. These biosignatures in exoplanetary atmospheres can potentially be detectable through high-contrast imaging instruments on future extremely large telescopes. To quantify the signal-to-noise ratio (S/N) with extremely large telescopes, we select up to 10 nearby rocky planets and simulate medium-resolution (R ∼ 1000) direct imaging of these planets using the Mid-infrared ELT Imager and Spectrograph (ELT/METIS, 3–5.6 μm) and the High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (ELT/HARMONI, 0.5–2.45 μm). We calculate the S/N for the detection of biosignatures including CH4, O2, H2O, and CO2. Our results show that GJ 887 b has the highest detection of S/N for biosignatures, and Proxima Cen b exhibits the only detectable CO2 among the targets for ELT/METIS direct imaging. We also investigate the TRAPPIST-1 system, the archetype of nearby transiting rocky planet systems, and compare the biosignature detection of transit spectroscopy with JWST versus direct spectroscopy with ELT/HARMONI. Our findings indicate JWST is more suitable for detecting and characterizing the atmospheres of transiting planet systems such as TRAPPIST-1 that are relatively further away and have smaller angular separations than more nearby nontransiting planets.

Spatially resolved mock observations of stellar kinematics: full radiative transfer treatment of simulated galaxies

ABSTRACT We present a framework to build realistic mock spectroscopic observations for state-of-the-art hydrodynamical simulations, using high spectral resolution stellar population models and full radiative transfer treatment with skirt. As a first application, we generate stellar continuum mock observations for the Auriga cosmological zoom simulations emulating integral-field observations from the Sydney–AOO Multi-object Integral Field Spectrograph (SAMI) Galaxy Survey. We perform spectral fitting on our synthetic cubes and compute the resulting rotation velocity (Vrot) and velocity dispersion within 1Re (σe) for a subset of the Auriga sample. We find that the kinematics produced by Auriga are in good agreement with the observations from the SAMI galaxy survey after taking into account the effects of dust and the systematics produced by the observation limitations. We also explore the effects of seeing convolution, inclination, and attenuation on the line-of-sight velocity distribution. For highly inclined galaxies, these effects can lead to an artificial decrease in the measured V/σ by nearly a factor of two (after inclination correction). We also demonstrate the utility of our method for high-redshift galaxies by emulating spatially resolved continuum spectra from the Large Early Galaxy Census (LEGA-C) survey and, looking forward, the European Extremely Large Telescope (E-ELT) High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI). Our framework represents a crucial link between the ground truth for stellar populations and kinematics in simulations and the observed stellar continuum observations at low and high redshift.

The Mass of the Black Hole in NGC 5273 from Stellar Dynamical Modeling

We present a new constraint on the mass of the black hole in the active S0 galaxy NGC 5273. Due to the proximity of the galaxy at 16.6 ± 2.1 Mpc, we were able to resolve and extract the bulk motions of stars near the central black hole using adaptive-optics-assisted observations with the Gemini Near-infrared Integral Field Spectrograph, as well as constrain the large-scale kinematics using archival Spectroscopic Areal Unit for Research and Optical Nebulae spectroscopy. High-resolution Hubble Space Telescope imaging allowed us to generate a surface-brightness decomposition, determine approximate mass-to-light ratios for the bulge and disk, and obtain an estimate for the disk inclination. We constructed an extensive library of dynamical models using the Schwarzschild orbit-superposition code FORSTAND, exploring a range of disk and bulge shapes, halo masses, etc. We determined a black hole mass of M • = [0.5–2] × 107 M ⊙, where the low side of the range is in agreement with the reverberation mapping measurement of M • = [4.7 ± 1.6] × 106 M ⊙. NGC 5273 is one of the few nearby galaxies that hosts a broad-lined active galactic nucleus, allowing a crucial comparison of black hole masses derived from independent mass-measurement techniques.

The AGNIFS survey: spatially resolved observations of hot molecular and ionized outflows in nearby active galaxies

ABSTRACTWe present the hot molecular and warm ionized gas kinematics for 33 nearby (0.001 ≲ z ≲ 0.056) X-ray selected active galaxies using the H$_2\, 2.1218\, \mu$m and Br γ emission lines observed in the K band with the Gemini near-infrared integral field spectrograph. The observations cover the inner 0.04–2 kpc of each active galactic nucleus at spatial resolutions of 4–250 pc with a velocity resolution of σinst ≈ 20 ${\rm km\, s^{-1}}$. We find that 31 objects (94 per cent) present a kinematically disturbed region (KDR) seen in ionized gas, while such regions are observed in hot molecular gas for 25 galaxies (76 per cent). We interpret the KDR as being due to outflows with masses of 102–107 and 100–104 M⊙ for the ionized and hot molecular gas, respectively. The ranges of mass-outflow rates ($\dot{M}_{\rm out}$) and kinetic power ($\dot{E}_{\rm K}$) of the outflows are 10−3–101 M⊙ yr−1 and ∼1037–1043 erg s−1 for the ionized gas outflows, and 10−5–10−2 M⊙ yr−1 and 1035–1039 erg s−1 for the hot molecular gas outflows. The median coupling efficiency in our sample is $\dot{E}_{\mathrm{K}}/L_{\rm bol}\approx 1.8\times 10^{-3}$ and the estimated momentum fluxes of the outflows suggest they are produced by radiation-pressure in low-density environment, with possible contribution from shocks.

SUPER VII. morphology and kinematics of H α emission in AGN host galaxies at cosmic noon using SINFONI

ABSTRACTWe present spatially resolved H α properties of 21 type 1 AGN host galaxies at z ∼ 2 derived from the SUPER survey. These targets were observed with the adaptive optics capabilities of the SINFONI spectrograph, a near-infrared integral field spectrograph, that provided a median spatial resolution of 0.3 arcsec (∼2 kpc). We model the H α emission line profile in each pixel to investigate whether it traces gas in the narrow line region or if it is associated with star formation. To do this, we first investigate the presence of resolved H α emission after subtracting the AGN PSF. We find extended H α emission in 16 out of the 21 type 1 AGN host galaxies (76 per cent). Based on the BPT diagnostics, optical line flux ratios and line widths (FWHM), we show that the H α emission in five galaxies is ionized by the AGN (30 per cent), in four galaxies by star formation (25 per cent) and for the rest (45 per cent), the ionization source is unconstrained. Two galaxies show extended H α FWHM >600 km s−1, which is interpreted as a part of an AGN-driven outflow. Morphological and kinematic maps of H α emission in targets with sufficient signal-to-noise ratio suggest the presence of rotationally supported discs in six galaxies and possible presence of companions in four galaxies. In two galaxies, we find an anticorrelation between the locations of extended H α emission and [O iii]-based ionized outflows, indicating possible negative feedback at play. However, in the majority of galaxies, we do not find evidence of outflows impacting H α-based star formation.

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

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 1045.7 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 Ṁout,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.

Sky coverage assessment for the European ELT: a joint evaluation for MAORY/MICADO and HARMONI

The instruments developed for the upcoming Extremely Large Telescopes (ELTs) will need efficient adaptive optics (AO) systems to correct the effects of the atmospheric turbulence and allow imaging at the highest angular resolution. One of the most important requirements for ELT AO-assisted instruments will be to deliver diffraction-limited images in a significant part of the sky. For that, the instruments will be equipped with laser guide stars (LGSs) providing most of the information required by AO instruments. But even with LGSs, AO systems still require the use of natural guide stars (NGSs) to compensate for image motion (jitter) and some low order aberrations. These NGSs are eventually limiting the fraction of the sky that can be achieved by AO systems, the so-called sky coverage (SC). We first present the SC assessment methods used for high angular resolution monolithic optical and near-infrared integral field spectrograph (HARMONI) and multiconjugate adaptive optics relay/multi-AO imaging camera for deep observations (MAORY/MICADO), that are both instruments for the ELT of the European Southern Observatory (ESO). They are based on a semianalytical description of the main contributors in the AO error budget, allowing for a fast estimation of the residual jitter. As such, these methods are well suited for statistical estimation of the SC on multiple science fields and/or to efficiently explore the system parameter space. We then compute the SC of the two instruments in cosmological fields from the cosmic assembly near-IR deep extragalactic legacy survey catalog. The goal is to provide an insight on the possibilities given by two different types of tomographic AO systems, i.e., laser tomography AO with HARMONI and multiconjugate AO with MAORY, on the same telescope. In particular, we show that HARMONI and MAORY/MICADO are complementary, meaning that the overall SC of ESO’s ELT is much improved for applications common to both systems.

Monitoring Inner Regions in the RY Tau Jet

We present multiepoch observations of the RY Tau jet for Hα and [Fe ii] 1.644 μm emission lines obtained with the Subaru Coronagraphic Extreme-AO and Visible Aperture Masking Polarimetric Imager for Resolved Exoplanetary Structures (VAMPIRES), Gemini Near-infrared Integral Field Spectrograph, and Keck/OSIRIS in 2019–2021. These data show a series of four knots within 1″ consistent with the proper motion of ∼0.″3 yr−1, analogous to the jets associated with another few active T Tauri stars. However, the spatial intervals between the knots suggest the time intervals of the ejections of about 1.2, 0.7, and 0.7 yr, significantly shorter than those estimated for the other stars. These Hα images contrast with the archival Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet Research and Zurich IMaging POLarimeter (ZIMPOL) observations from 2015, which showed only a single knot-like feature at ∼0.″25. The difference between the 2015 and 2019–2021 epochs suggests an irregular ejection interval within the six-year range. Such variations of the jet ejection may be related to a short-term (<1 yr) variability of the mass accretion rate. We compared the peaks of the Hα emissions with the ZIMPOL data taken in 2015, showing the brighter profile at the base (<0.″3) than the 2020–2021 VAMPIRES profiles due to time-variable mass ejection rates or the heating–cooling balance in the jet. The observed jet knot structures may be alternatively attributed to stationary shocks, but a higher angular resolution is required to confirm its detailed origin.

Gemini NIFS survey of feeding and feedback processes in nearby active galaxies – VI. Stellar populations

ABSTRACT We use Gemini Near-Infrared Integral Field Spectrograph (NIFS) adaptive optics assisted data cubes to map the stellar population of the inner few hundred parsec of a sample of 18 nearby Seyfert galaxies. The near-infrared light is dominated by the contribution of young to intermediate-age stellar populations, with light-weighted mean ages ‹t›L ≲ 1.5 Gyr. Hot dust (HD) emission is centrally peaked (in the unresolved nucleus), but it is also needed to reproduce the continuum beyond the nucleus in nearly half of the sample. We have analysed the stellar population properties of the nuclear region and their relation with more global properties of the galaxies. We find a correlation between the X-ray luminosity and the contributions from the HD, featureless continuum (FC), and reddening AV. We attribute these correlations to the fact that all these properties are linked to the mass accretion rate to the active galactic nuclei (AGNs). We also find a correlation of the bolometric luminosity log($L_{\rm Bol_{\rm obs}}$) with the mass-weighted mean age of the stellar population, interpreted as due a delay between the formation of new stars and the triggering/feeding of the AGN. The gas reaching the supermassive black hole is probably originated from mass loss from the already somewhat evolved intermediate-age stellar population (‹t›L ≲ 1.5 Gyr). In summary, our results show that there is a significant fraction of young to intermediate-age stellar populations in the inner few 100 pc of active galaxies, suggesting that this region is facing a rejuvenation process in which the AGN, once triggered, precludes further star formation, in the sense that it can be associated with the lack of new star formation in the nuclear region.

HARMONI view of the host galaxies of active galactic nuclei around cosmic noon

Context. The formation and evolution of galaxies appear linked to the growth of supermassive black holes, as evidenced by empirical scaling relations in nearby galaxies. Understanding this co-evolution over cosmic time requires the revelation of the dynamical state of galaxies and the measurement of the mass of their central black holes (MBH) at a range of cosmic distances. Bright active galactic nuclei (AGNs) are ideal for this purpose. Aims. The High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI), the first light integral-field spectrograph for the Extremely Large Telescope, will transform visible and near-infrared ground-based astrophysics thanks to its advances in sensitivity and angular resolution. We aim to analyse the capabilities of HARMONI to reveal the stellar morpho-kinematic properties of the host galaxies of AGNs at about cosmic noon. Methods. We made use of the simulation pipeline for HARMONI (HSIM) to create mock observations of representative AGN host galaxies at redshifts around cosmic noon. We used observations taken with the Multi Unit Spectroscopic Explorer of nearby galaxies showing different morphologies and dynamical stages combined with theoretical AGN spectra to create the target inputs for HSIM. Results. According to our simulations, an on-source integration time of three hours should be enough to measure the MBH and to trace the morphology and stellar kinematics of the brightest host galaxies of AGNs beyond cosmic noon. For host galaxies with stellar masses &lt; 1011 M⊙, longer exposure times are mandatory to spatially resolve the stellar kinematics.

Gemini NIFS survey of feeding and feedback in nearby active galaxies – V. Molecular and ionized gas kinematics

ABSTRACT We study the gas distribution and kinematics of the inner kpc of six moderately luminous (43.43 ≤ log Lbol ≤ 44.83) nearby (0.004 ≤ z ≤ 0.014) Seyfert galaxies observed with the Near-infrared Integral Field Spectrograph (NIFS) in the J ($1.25\,\mu$m) and K ($2.2\,\mu$m) bands. We analyse the most intense emission lines detected on these spectral wavebands: [Fe ii] $1.2570\, \mu$m and Paβ, which trace the ionized gas in the partially and fully ionized regions, and $\mathrm{ H}_2 \ 2.1218\, \mu$m, which traces the hot (∼2000 K) molecular gas. The dominant kinematic component is rotation in the disc of the galaxies, except for the ionized gas in NGC 5899 that shows only weak signatures of a disc component. We find ionized gas outflow in four galaxies, while signatures of H2 outflows are seen in three galaxies. The ionized gas outflows display velocities of a few hundred km s−1, and their mass outflow rates are in the range 0.005–12.49 M⊙ yr−1. Their kinetic powers correspond to 0.005–0.7 per cent of the active galactic nuclei (AGN) bolometric luminosities. Besides rotation and outflows signatures in some cases, the H2 kinematics also reveals inflows in three galaxies. The inflow velocities are 50–80 km s−1 and the mass inflow rates are in the range 1–9 × 10−4 M⊙ yr−1 for hot molecular gas. These inflows might be only the hot skin of the total inflowing gas, which is expected to be dominated by colder gas. The mass inflow rates are lower than the current accretion rates to the AGN, and the ionized outflows are apparently disturbing the gas in the inner kpc.

Direct imaging and spectroscopy of exoplanets with the ELT/HARMONI high-contrast module

Combining high-contrast imaging with medium-resolution spectroscopy has been shown to significantly boost the direct detection of exoplanets. HARMONI, one of the first-light instruments to be mounted on ESO’s future extremely large telescope (ELT), will be equipped with a single-conjugated adaptive optics system to reach the diffraction limit of the ELT in theHandKbands, a high-contrast module dedicated to exoplanet imaging, and a medium-resolution (up toR = 17 000) optical and near-infrared integral field spectrograph. When combined, these systems will provide unprecedented contrast limits at separations between 50 and 400 mas. This paper is aimed at estimating the capabilities of the HARMONI high-contrast module for the direct detection of young giant exoplanets. We use an end-to-end model of the instrument to simulate high-contrast observations performed with HARMONI, based on realistic observing scenarios and conditions. We then analyze these data with the so-called “molecule mapping” technique combined with a matched-filter approach in order to disentangle companions from the host star and tellurics and to increase the signal-to-noise ratio (S/N) of the planetary signal. We detected planets above 5σat contrasts up to 16 mag and separations down to 75 mas in several spectral configurations of the instrument. We show that molecule mapping allows for the detection of companions up to 2.5 mag fainter compared to state-of-the-art high-contrast imaging techniques based on angular differential imaging. We also demonstrate that the performance is not strongly affected by the spectral type of the host star and we show that we are able to reach close sensitivities for the best three quartiles of observing conditions at Armazones, which means that HARMONI could be used in near-critical observations during 60 to 70% of telescope time at the ELT. Finally, we simulated planets from population synthesis models to further explore the parameter space that HARMONI and its high-contrast module will open up and compare this to the current high-contrast instrumentation.

Powerful multiphase outflows in the central region of Cygnus A

ABSTRACT We use Gemini Near-Infrared Integral Field Spectrograph (NIFS) observations of the inner 3.5 × 3.5 kpc2 of the radio galaxy Cygnus A to map the gas excitation and kinematics at a spatial resolution of 200 pc. The emission of the ionized gas shows a biconical morphology, with half-opening angle of 45○ and oriented along the position angle of the radio jet. Coronal line emission is seen within the cone, up to 1.75 kpc from the nucleus, with higher ionization gas observed in the easterly side. The H2 and [Fe ii] emission lines are consistent with excitation by the central AGN, with some contribution of shocks to the south-west of the nucleus. The gas visual extinction and electron density are larger than those from optical-based measurements, consistent with the fact that near-IR observations penetrate deeply into the gas emission structure, probing denser and more obscured regions. The gas kinematics shows two components: (i) a rotating disc with kinematic position angle of Ψ0 = 21○ ± 2○, seen both in ionized and molecular gas, and (ii) outflows with velocities of up to 600 km s−1 observed within the ionization cone in ionized gas and restricted to inner 0.5 arcsec in molecular gas. The mass outflow rate in ionized gas is in the range $\sim \! 100\!-\!280\, {\rm M_\odot \, yr^{-1}}$ and the kinetic power of the outflow corresponds to 0.3–3.3 per cent of the AGN bolometric luminosity, indicating that the outflows in Cygnus A may be effective in suppressing star formation.

A Comparison of Stellar Kinematics Derived from Two Gemini NIFS Reduction Pipelines

Abstract The Gemini Near-infrared Integral Field Spectrograph (NIFS) reduction pipeline is widely used to reduce NIFS data. However, there are critical known limitations. A new NIFS reduction pipeline has recently been developed and solves several of these problems. We present a comparison of stellar kinematics derived from the new and old data reduction pipelines, as well as recommendations for optimal NIFS data reduction.

Simulating gas kinematic studies of high-redshift galaxies with the HARMONI integral field spectrograph

ABSTRACT We present simulated observations of gas kinematics in a galaxy formed in a 10 pc resolution cosmological simulation with the hydrodynamical + N-body code ramses, using the new ramses2hsim pipeline with the simulated observing pipeline (hsim) for the Extremely Large Telescope High Angular Resolution Monolithic Optical and Near-infrared Integral field spectrograph (HARMONI IFS). We post-process the galaxy's gas kinematics and Hα line emission for each simulation cell, and integrate the emission to produce an extinction-corrected input cube. We then simulate observations of the input cube with HARMONI, for a range of exposure times, spatial sampling, and spectral resolution. We analyse the mock observations to recover galaxy properties such as its kinematics and compare with the known simulation values. We investigate the cause of biases between the ‘real’ and ‘observed’ kinematic values, demonstrating the sensitivity of the inferred rotation curve to knowledge of the instrument’s point spread function.

Ionized and hot molecular outflows in the inner 500 pc of NGC 1275

ABSTRACT The role of feedback from active galactic nuclei (AGNs) in the evolution of galaxies is still not fully understood, mostly due to the lack of observational constraints in the multiphase gas kinematics on the 10–100 pc scales. We have used the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the molecular and ionized gas kinematics in the inner 900 × 900 pc2 of the Seyfert galaxy NGC 1275 at a spatial resolution of ∼70 pc. From the fitting of the CO absorption bandheads in the K band, we derive a stellar velocity dispersion of 265 ± 26 km s−1, which implies a black hole mass of $M_{\rm SMBH}=1.1^{+0.9}_{-0.5}\times 10^9$ M⊙. We find hot (T ≳ 1000 K) molecular and ionized outflows with velocities of up to 2000 km s−1 and mass outflow rates of $2.7\times 10^{-2}$ and $1.6\, {\rm M_\odot }$ yr−1, respectively, in each of these gas phases. The kinetic power of the ionized outflows corresponds to only 0.05 per cent of the luminosity of the AGN of NGC 1275, indicating that they are not powerful enough to provide significant AGN feedback, but may be effective in redistributing the gas in the central region of the galaxy. The AGN-driven outflows seem to be responsible for the shocks necessary to produce the observed H2 and [Fe ii] line emission.

Evidence for an accreting massive black hole in He 2–10 from adaptive optics integral field spectroscopy

ABSTRACT Henize 2–10 is a blue dwarf galaxy with intense star formation and one the most intriguing question about it is whether or not it hosts an accreting massive black hole. We use H and K-band integral field spectra of the inner 130 pc × 130 pc of He 2–10 to investigate the emission and kinematics of the gas at unprecedented spatial resolution. The observations were done using the Gemini Near-Infrared Integral Field Spectrograph (NIFS) operating with the ALTAIR adaptive optics module and the resulting spatial resolutions are 6.5 and 8.6 pc in the K and H bands, respectively. Most of the line emission is due to excitation of the gas by photoionization and shocks produced by the star forming regions. In addition, our data provide evidence of emission of gas excited by an active galactic nucleus located at the position of the radio and X-ray sources, as revealed by the analysis of the emission-line ratios. The emission lines from the ionized gas in the field present two kinematic components: one narrow with a velocity field suggesting a disc rotation and a broad component due to winds from the star forming regions. The molecular gas shows only the narrow component. The stellar velocity dispersion map presents an enhancement of about 7 km s−1 at the position of the black hole, consistent with a mass of $1.5^{+1.3}_{-1.3}\times 10^6$ M⊙.

Monitoring dusty sources in the vicinity of Sagittarius A*

Context. Several dusty infrared sources traced on their orbits around Sgr A* with SINFONI and NACO mounted at the VLT/Chile show near-infrared (NIR) excess and Doppler-shifted line emission. We investigate these sources in order to clarify their nature and compare their relationship to other observed NIR objects close to Sgr A*. Aims. Using SINFONI, we are able to determine the spectroscopic properties of the dusty infrared sources. Furthermore, we can extract spatial and velocity information of these objects. We are able to identify X7, X7.1, X8, G1, DSO/G2, D2, D23, D3, D3.1, D5, and D9 in the Doppler-shifted line maps of the SINFONI H + K data. From our K- and L′-band NACO data, we derive the related magnitudes of the brightest sources located west of Sgr A*. Methods. For determining the line of sight velocity information and to investigate single emission lines, we used the near-infrared integral field spectrograph SINFONI datasets between 2005 and 2015. For the kinematic analysis, we used NACO datasets from the years between 2002 and 2018. This study was done in the H, Ks, and L′ band. From the 3D SINFONI data-cubes, we extracted line maps in order to derive positional information for the sources. In the NACO images, we identified the dusty counterpart of the objects. When possible, we determined the Keplerian orbits and applied a photometric analysis. Results. The spectrum of the investigated objects show a Doppler-shifted Brγ and HeI line emission. For some objects west of Sgr A*, we additionally find [FeIII] line emission that can be clearly distinguished from the background. A one-component blackbody model fits the extracted near-infrared flux for the majority of the investigated objects, with the characteristic dust temperature of 500 K. The photometric derived H- and KS-band magnitudes are between magH &gt; 22.5 and magk = 18.1+0.3−0.8 for the dusty sources. For the H-band magnitudes we can provide an upper limit. For the bright dusty sources D2, D23, and D3, the Keplerian orbits are elliptical with a semi-major axis of aD2 = (749 ± 13) mas, aD23 = (879 ± 13), and aD3 = (880 ± 13) mas. For the DSO/G2, a single-temperature and a two-component blackbody model is fitted to the H-, K-, L′-, and M-band data, while the two-component model that consists of a star and an envelope fits its SED better than an originally proposed single-temperature dusty cloud. Conclusions. The spectroscopic analysis indicates that the investigated objects could be dust-embedded pre-main-sequence stars. The Doppler-shifted [FeIII] line can be spectroscopically identified in several sources that are located between 17:45:40.05 and 17:45:42.00 in Dec However, the sources with a DEC less than 17:45:40.05 show no [FeIII] emission. Therefore, these two groups show different spectroscopic features that could be explained by the interaction with a non-spherical outflow that originates at the position of Sgr A*. Following this, the hot bubble around Sgr A* consists out of isolated sources with [FeIII] line emission that can partially account for the previously detected [FeIII] distribution on larger scales.

Observations of AGN feeding and feedback on Nuclear, Galactic, and Extragalactic Scales

AbstractWe investigate the processes of active galactic nuclei (AGN) feeding and feedback in the narrow line regions (NLRs) and host galaxies of nearby AGN through spatially resolved spectroscopy with the Gemini Near-Infrared Integral Field Spectrograph (NIFS) and the Hubble Space Telescope’s Space Telescope Imaging Spectrograph (STIS). We examine the connection between nuclear and galactic inflows and outflows by adding long-slit spectra of the host galaxies from Apache Point Observatory. We demonstrate that nearby AGN can be fueled by a variety of mechanisms. We find that the NLR kinematics can often be explained by in situ ionization and radiative acceleration of ambient gas, often in the form of dusty molecular spirals that may be the fueling flow to the AGN.