scholarly journals Mapping the ionized gas of the metal-poor H ii galaxy PHL 293B with MEGARA

2020 ◽  
Vol 498 (2) ◽  
pp. 1638-1650
Author(s):  
C Kehrig ◽  
J Iglesias-Páramo ◽  
J M Vílchez ◽  
A Gil de Paz ◽  
S Duarte Puertas ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Photon Flux ◽  
Main Body ◽  
Ionized Gas ◽  
Stellar Cluster ◽  
Spatially Resolved ◽  
High Ionization ◽  
The Galaxy ◽  
Spatially Extended ◽  
Field Unit

ABSTRACT Here we report the first spatially resolved spectroscopic study for the galaxy PHL 293B using the high-resolution GTC/MEGARA integral field unit (IFU). PHL 293B is a local, extremely metal-poor, high ionization galaxy. This makes PHL 293B an excellent analogue for galaxies in the early Universe. The MEGARA aperture (∼ 12.5 arcsec × 11.3 arcsec) covers the entire PHL 293B main body and its far-reaching ionized gas. We created and discussed maps of all relevant emission lines, line ratios, and physical–chemical properties of the ionized ISM. The narrow emission gas appears to be ionized mainly by massive stars according to the observed diagnostic line ratios, regardless of the position across the MEGARA aperture. We detected low intensity broad emission components and blueshifted absorptions in the Balmer lines (H α,H β) which are located in the brightest zone of the galaxy ISM. A chemically homogeneity, across hundreds of parsecs, is observed in O/H. We take the oxygen abundance 12+log (O/H) = 7.64 ± 0.06 derived from the PHL 293B integrated spectrum as the representative metallicity for the galaxy. Our IFU data reveal for the first time that the nebular He iiλ4686 emission from PHL 293B is spatially extended and coincident with the ionizing stellar cluster, and allow us to compute its absolute He ii ionizing photon flux. Wolf-Rayet bumps are not detected excluding therefore Wolf-Rayet stars as the main He ii excitation source. The origin of the nebular He iiλ4686 is discussed.

scholarly journals High Velocity Ionized Gas near IRS 16

1989 ◽  
Vol 136 ◽  
pp. 525-526
Author(s):  
T. R. Geballe ◽  
J. B. Lugten
Keyword(s):  
High Velocity ◽  
Spectral Properties ◽  
Radial Flow ◽  
Line Emission ◽  
Compact Object ◽  
Characteristic Dimension ◽  
Ionized Gas ◽  
Spatially Resolved ◽  
The Galaxy ◽  
Important Means

An important means of studying the unusual activity within the central ~0.15 parsec of the galaxy is to obtain detailed information on the high velocity ionized gas there. This gas was first reported by Hall, Kleinmann, and Scoville (1982), who observed the He I line at 2.06 μm. Subsequent observations of this line and the Br ∝ and Br γ lines of H I (4.05 μm and 2.17 μm, respectively) by Geballe et al. (1984, 1987) have defined the coarse spatial and spectral properties more accurately. Briefly, the broad (i.e., |v| > 400 km/s) line emission, as observed at velocity resolutions as high as 400 km/s and angular resolutions as high as 2.5″ (1) extends approximately to +/– 700 km/s (e.g., see Fig. 1), (2) is spatially resolved, with a characteristic dimension of 3″, (3) is centered approximately on IRS 16C, and (4) appears to be due neither to rotational motion nor to a simple radial flow from or onto a single compact object. These properties are difficult to understand in terms of simple models, and point out the necessity for further measurements at higher spectral and spatial resolutions.

scholarly journals SDSS-IV MaNGA: Observational Evidence of a Density-bounded Region in a Lyα Emitter

2022 ◽  
Vol 924 (2) ◽  
pp. 47
Author(s):  
Abhishek Paswan ◽  
Kanak Saha ◽  
Claus Leitherer ◽  
Daniel Schaerer
Keyword(s):  
Gas Phase ◽  
Observational Evidence ◽  
Moderate Correlation ◽  
Spatially Resolved ◽  
Lyman Continuum ◽  
The Galaxy ◽  
Field Unit ◽  
Dust Distribution ◽  
First Time ◽  
Integral Field

Abstract Using integral field unit spectroscopy, we present here the spatially resolved morphologies of [S ii]λ6717,6731/Hα and [S ii]λ6717,6731/[O iii]λ5007 emission line ratios for the first time in a blueberry Lyα emitter (BBLAE) at z ∼ 0.047. Our derived morphologies show that the extreme starburst region of the BBLAE, populated by young (≤10 Myr), massive Wolf–Rayet stars, is [S ii] deficient, while the rest of the galaxy is [S ii] enhanced. We infer that the extreme starburst region is density-bounded (i.e., optically thin to ionizing photons), and the rest of the galaxy is ionization-bounded, indicating a Blister-type morphology. We find that the previously reported small escape fraction (10%) of Lyα photons is from our identified density-bounded H ii region of the BBLAE. This escape fraction is likely constrained by a porous dust distribution. We further report a moderate correlation between [S ii] deficiency and inferred Lyman continuum (LyC) escape fraction using a sample of confirmed LyC leakers studied in the literature, including the BBLAE studied here. The observed correlation also reveals its dependency on the stellar mass and gas-phase metallicity of the leaky galaxies. Finally, the future scope and implications of our work are discussed in detail.

scholarly journals A nuclear ionized gas outflow in the Seyfert 2 galaxy UGC 2024

2019 ◽  
Vol 487 (3) ◽  
pp. 3679-3692 ◽  
Author(s):  
Dania Muñoz-Vergara ◽  
Neil M Nagar ◽  
Venkatessh Ramakrishnan ◽  
Carolina Finlez ◽  
Thaisa Storchi-Bergmann ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Emission Lines ◽  
Ionized Gas ◽  
Full Field ◽  
North West ◽  
Gas Kinematics ◽  
Systemic Velocity ◽  
The Galaxy ◽  
Field Unit ◽  
Prime 2

ABSTRACT As part of a high-resolution observational study of feeding and feedback processes occurring in the vicinity of the active galactic nucleus in 40 galaxies, we observed the inner 3${^{\prime\prime}_{.}}$5 × 5 arcsec of the nearby spiral and Seyfert 2 galaxy UGC 2024 with the integral field unit of the Gemini-South Telescope. The observations enabled a study of the stellar and gas kinematics in this region at a spatial resolution of 0${^{\prime\prime}_{.}}$5 (218 pc), and a spectral resolution of 36  km s−1 over the wavelength range 4100–7300 Å. For the strongest emission-lines (H β, [$\rm{O\,{\small III}}$] λ5007 Å, H α, [$\rm{N\,{\small II}}$] λ6584 Å, and [$\rm{S\,{\small II}}$] λλ6717,6731 Å) we derived maps of the flux, radial velocity, and velocity dispersion. The flux distribution and kinematics of the [$\rm{O\,{\small III}}$] emission line are roughly symmetric around the nucleus: the radial velocity is close to systemic over the full field of view. The kinematics of the other strong emission lines trace both this systemic velocity component, and ordered rotation (with kinematic centre 0${^{\prime\prime}_{.}}$2 north-west of the nucleus). The stellar continuum morphology and kinematics are, however, asymmetrical around the nucleus. We interpret these unusual kinematics as the superposition of a component of gas rotating in the galaxy disc plus a ‘halo’ component of highly ionized gas. This halo either traces a quasi-spherical fountain with average radial velocity 200 km s−1, in which case the total nuclear outflow mass and momentum are 2 × 105 M⊙ and 4 × 107 M⊙ km s−1, respectively, or a dispersion supported halo created by a past nuclear starburst.

Unveiling the nuclear region of NGC 6868: Mapping the stellar population and ionized gas

2019 ◽  
Vol 15 (S359) ◽  
pp. 418-420
Author(s):  
João P. V. Benedetti ◽  
Rogério Riffel ◽  
Tiago V. Ricci ◽  
João E. Steiner ◽  
Rogemar A. Riffel ◽  
...  
Keyword(s):  
Stellar Population ◽  
Star Formation History ◽  
Nuclear Region ◽  
Stellar Kinematics ◽  
Ionized Gas ◽  
Formation History ◽  
The Galaxy ◽  
History Of ◽  
Field Unit ◽  
New Generation

AbstractWe mapped the stellar population and emission gas properties in the nuclear region of NGC 6868 using datacubes extracted with Gemini Multi-Object Spectrograph (GMOS) in the Integral Field Unit (IFU) mode. To obtain the star-formation history of this galaxy we used the starlight code together with the new generation of MILES simple stellar population models. The stellar population dominating (95% in light fraction) the central region of NGC 6868 is old and metal rich (~10 Gyr, 2.2 Z⊙). We also derived the kinematics and emission line fluxes of ionized gas with the IFSCube package. A rotation disk is clearly detected in the nuclear region of the galaxy and no broad components were detected. Also, there is a region where the emission lines disappear almost completely, probably due to diffuse ionized gas component. Channel maps, diagnostic diagrams and stellar kinematics are still under analysis.

The two-phase gas outflow in the Circinus Galaxy

2019 ◽  
Vol 15 (S359) ◽  
pp. 272-273
Author(s):  
M. A. Fonseca-Faria ◽  
A. Rodríguez-Ardila
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Temperature Sensitive ◽  
Ionized Gas ◽  
Two Phase ◽  
North West ◽  
Gas Kinematics ◽  
High Ionization ◽  
The Galaxy ◽  
Sensitive Line

AbstractWe employ Multi Unit Spectroscopic Explorer (MUSE) data to study the ionized and very ionized gas phase of the feedback in Circinus, the closest Seyfert 2 galaxy. The analysis of the nebular emission allowed us to detect a remarkable high-ionization gas outflow, out of the galaxy plane, traced by the coronal lines [Fe viii] 6089Å and [Fe x] 6374Å, extending up to 700 parsecs north-west from the nucleus. The gas kinematics reveal expanding gas shells with velocities of a few hundred km s-1, spatially coincident with prominent hard X-ray emission detected by Chandra. Density and temperature sensitive line ratios show that the extended high-ionization gas is characterized by a temperature of up to 18000 K and a gas density of ne > 102 cm−3. We propose two scenarios consistent with the observations to explain the high-ionization component of the outflow: an active galactic nuclei (AGN) ejection that took place ⁓105 yr ago or local gas excitation by shocks produced by the passage of a radio jet.

scholarly journals Evidence for the formation of the young counter-rotating stellar disk from gas acquired by IC 719

2018 ◽  
Vol 616 ◽  
pp. A22 ◽  
Author(s):  
A. Pizzella ◽  
L. Morelli ◽  
L. Coccato ◽  
E. M. Corsini ◽  
E. Dalla Bontà ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Formation Rate ◽  
Chemical Properties ◽  
Stellar Disk ◽  
Large Field ◽  
Ionized Gas ◽  
Counter Rotation ◽  
The Galaxy ◽  
Gas Accretion

Aims. The formation scenario of extended counter-rotating stellar disks in galaxies is still debated. In this paper, we study the S0 galaxy IC 719 known to host two large-scale counter-rotating stellar disks in order to investigate their formation mechanism. Methods. We exploit the large field of view and wavelength coverage of the Multi Unit Spectroscopic Explorer (MUSE) spectrograph to derive two-dimensional (2D) maps of the various properties of the counter-rotating stellar disks, such as age, metallicity, kinematics, spatial distribution, the kinematical and chemical properties of the ionized gas, and the dust map. Results. Due to the large wavelength range, and in particular to the presence of the Calcium Triplet λλ8498, 8542, 8662 Å (CaT hereafter), the spectroscopic analysis allows us to separate the two stellar components in great detail. This permits precise measurement of both the velocity and velocity dispersion of the two components as well as their spatial distribution. We derived a 2D map of the age and metallicity of the two stellar components, as well as the star formation rate and gas-phase metallicity from the ionized gas emission maps. Conclusions. The main stellar disk of the galaxy is kinematically hotter, older, thicker and with larger scale-length than the secondary disk. There is no doubt that the latter is strongly linked to the ionized gas component: they have the same kinematics and similar vertical and radial spatial distribution. This result is in favor of a gas accretion scenario over a binary merger scenario to explain the origin of counter-rotation in IC 719. One source of gas that may have contributed to the accretion process is the cloud that surrounds IC 719.

scholarly journals Old and new major mergers in the SOSIMPLE galaxy, NGC 7135

2021 ◽  
Vol 502 (2) ◽  
pp. 2296-2307
Author(s):  
Thomas A Davison ◽  
Harald Kuntschner ◽  
Bernd Husemann ◽  
Mark A Norris ◽  
Julianne J Dalcanton ◽  
...  
Keyword(s):  
Star Formation History ◽  
Ex Situ ◽  
Spectral Fitting ◽  
Spatially Resolved ◽  
Counter Rotation ◽  
Formation History ◽  
The Galaxy ◽  
Nearby Galaxies ◽  
Chemical Distribution ◽  
Field Unit

ABSTRACT The simultaneous advancement of high resolution integral field unit spectroscopy and robust full-spectral fitting codes now make it possible to examine spatially resolved kinematic, chemical composition, and star-formation history from nearby galaxies. We take new MUSE data from the snapshot optical spectroscopic imaging of mergers and pairs for legacy Exploration (SOSIMPLE) survey to examine NGC 7135. With counter-rotation of gas, disrupted kinematics and asymmetric chemical distribution, NGC 7135 is consistent with an ongoing merger. Though well hidden by the current merger, we are able to distinguish stars originating from an older merger, occurring 6–10 Gyr ago. We further find a gradient in ex-situ material with galactocentric radius, with the accreted fraction rising from 0 per cent in the galaxy centre, to ∼7 per cent within 0.6 effective radii.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

On the path toward a universal outflow mechanism in light of NGC 4151 and NGC 1068

2020 ◽  
Vol 15 (S359) ◽  
pp. 283-284
Author(s):  
D. May ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Near Infrared ◽  
Feedback Mechanism ◽  
Data Cube ◽  
Low Velocity ◽  
Ionized Gas ◽  
Ngc 4151 ◽  
Molecular Outflow ◽  
Ngc 1068 ◽  
Field Unit ◽  
First Time

AbstractWe use near-infrared Integral Field Unit (IFU) data to analyze the galaxies NGC 4151 and NGC 1068, which have very different Eddington ratios - ˜50 times lower for NGC 4151. Together with a detailed data cube treatment methodology, we reveal remarkable similarities between both AGN, such as the detection of the walls of an “hourglass” structure for the low-velocity [Fe ii] emission with the high-velocity emission within this hourglass; a molecular outflow - detected for the first time in NGC 4151; and the fragmentation of an expanding molecular bubble into bullets of ionized gas. Such observations suggest that NGC 4151 could represent a less powerful and more compact version of the outflow seen in NGC 1068, suggesting a universal feedback mechanism acting in quite different AGN.

scholarly journals Survival of molecular gas in a stellar feedback-driven outflow witnessed with the MUSE TIMER project and ALMA

2019 ◽  
Vol 488 (3) ◽  
pp. 3904-3928 ◽  
Author(s):  
Ryan Leaman ◽  
Francesca Fragkoudi ◽  
Miguel Querejeta ◽  
Gigi Y C Leung ◽  
Dimitri A Gadotti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Mechanical Energy ◽  
Molecular Gas ◽  
Ionized Gas ◽  
Star Forming ◽  
Stellar Feedback ◽  
Dominant Component ◽  
The Galaxy ◽  
Field Lines

ABSTRACT Stellar feedback plays a significant role in modulating star formation, redistributing metals, and shaping the baryonic and dark structure of galaxies – however, the efficiency of its energy deposition to the interstellar medium is challenging to constrain observationally. Here we leverage HST and ALMA imaging of a molecular gas and dust shell ($M_{\mathrm{ H}_2} \sim 2\times 10^{5}\, {\rm M}_{\odot }$) in an outflow from the nuclear star-forming ring of the galaxy NGC 3351, to serve as a boundary condition for a dynamical and energetic analysis of the outflowing ionized gas seen in our MUSE TIMER survey. We use starburst99 models and prescriptions for feedback from simulations to demonstrate that the observed star formation energetics can reproduce the ionized and molecular gas dynamics – provided a dominant component of the momentum injection comes from direct photon pressure from young stars, on top of supernovae, photoionization heating, and stellar winds. The mechanical energy budget from these sources is comparable to low luminosity active galactic neuclei, suggesting that stellar feedback can be a relevant driver of bulk gas motions in galaxy centres – although here ≲10−3 of the ionized gas mass is escaping the galaxy. We test several scenarios for the survival/formation of the cold gas in the outflow, including in situ condensation and cooling. Interestingly, the geometry of the molecular gas shell, observed magnetic field strengths and emission line diagnostics are consistent with a scenario where magnetic field lines aided survival of the dusty ISM as it was initially launched (with mass-loading factor ≲1) from the ring by stellar feedback. This system’s unique feedback-driven morphology can hopefully serve as a useful litmus test for feedback prescriptions in magnetohydrodynamical galaxy simulations.

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