scholarly journals The nuclear region of NGC 613 – II. Kinematics and stellar archaeology

2020 ◽  
Vol 496 (1) ◽  
pp. 943-958
Author(s):  
Patrícia da Silva ◽  
R B Menezes ◽  
J E Steiner ◽  
Luciano Fraga
Keyword(s):  
Near Infrared ◽  
Spectral Synthesis ◽  
Weighted Average ◽  
Stellar Populations ◽  
Data Cube ◽  
Synthesis Methods ◽  
H Ii Regions ◽  
Stellar Kinematics ◽  
Stellar Rotation ◽  
Gas Kinematics

ABSTRACT In this work, we continue the study of the central region of NGC 613 by da Silva, Menezes & Steiner (Paper I), by analysing the stellar and gas kinematics and the stellar archaeology in optical and near-infrared data cubes. The high spatial resolution of the Gemini Multi-Object Spectrograph (GMOS) data cube allowed the detection, using spectral synthesis methods, of an inner circumnuclear ring, with a radius of ∼1 arcsec, composed of ∼109-yr stellar populations. Such a ring is located between the nucleus and the circumnuclear ring composed by H ii regions detected in previous works. Besides that, there is a stellar rotation around the nucleus and the rings follow the same direction of rotation with different velocities. The intensity-weighted average stellar velocity dispersion at the centre is 92 ± 3 km s−1. Three distinct gas outflow components were detected. The direction of the outflow observed with the H α emission line is compatible with the direction of the previously observed radio jet. The direction of one of the outflows detected in the [O iii]λ5007 emission coincides with the axis of the ionization cone. There is no difference regarding the stellar populations and the stellar kinematics along the double stellar emission, probably separated by a dust lane as mentioned in Paper I, confirming that they are part of the same structure.

scholarly journals Near-infrared spectroscopic indices for unresolved stellar populations

2019 ◽  
Vol 621 ◽  
pp. A60 ◽  
Author(s):  
P. François ◽  
L. Morelli ◽  
A. Pizzella ◽  
V. D. Ivanov ◽  
L. Coccato ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Near Infrared ◽  
Spectral Synthesis ◽  
Population Analysis ◽  
Line Strength ◽  
Stellar Populations ◽  
Morphological Type ◽  
Resolving Power ◽  
Data Set ◽  
Hubble Sequence

Context. A new generation of spectral synthesis models has been developed in recent years, but there is no matching set of template galaxy spectra, in terms of quality and resolution, for testing and refining the new models. Aims. Our main goal is to find and calibrate new near-infrared spectral indices along the Hubble sequence of galaxies which will be used to obtain additional constraints to the population analysis based on medium-resolution integrated spectra of galaxies. Methods. Spectra of previously studied and well-understood galaxies with relatively simple stellar populations (e.g., ellipticals or bulge dominated galaxies) are needed to provide a baseline data set for spectral synthesis models. Results. X-shooter spectra spanning the optical and infrared wavelengths (350–2400 nm) of bright nearby elliptical galaxies with a resolving power of R ∼ 4000–5400 were obtained. Heliocentric systemic velocity, velocity dispersion, and Mg, Fe, and Hβ line-strength indices are presented. Conclusions. We present a library of very-high-quality spectra of galaxies covering a large range of age, metallicity, and morphological type. Such a dataset of spectra will be crucial to addressing important questions of the modern investigation concerning galaxy formation and evolution.

The birth of an AGN: NGC 4111

2020 ◽  
Vol 15 (S359) ◽  
pp. 362-363
Author(s):  
Gabriel R. H. Roier ◽  
Thaisa Storchi-Bergmann
Keyword(s):  
Near Infrared ◽  
Dwarf Galaxy ◽  
Molecular Gas ◽  
Stellar Kinematics ◽  
Gas Kinematics ◽  
Integral Field Spectroscopy ◽  
Optical Images ◽  
Counter Rotation ◽  
The Galaxy ◽  
Nearby Galaxies

AbstractWe have used near-infrared and optical Integral Field Spectroscopy along with optical images to study the inner 100 pc of NGC 4111 in a project to investigate the stellar and gas kinematics in the surroundings of Supermassive Black Holes in nearby galaxies. We have compared the inner stellar and gas kinematics with data of the outer regions of the galaxy. We found larger scale hot ionized gas and warm molecular gas within the inner 100 pc that is in counter-rotation relative to the stellar kinematics, a sign of inflowing material that is probably triggering an Active Galactic Nucleus. This is supported by the nuclear X-ray emission which is heating the molecular gas and causing it to emit. The presence of large amounts of dust in a polar ring suggests that this is a fairly recent event probably due to the capture of a dwarf galaxy.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

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 Extragalactic GCs in the near-infrared: genuinely old in E/S0's?

2009 ◽  
Vol 5 (S262) ◽  
pp. 315-316
Author(s):  
Ana L. Chies-Santos ◽  
Søren S. Larsen
Keyword(s):  
Globular Cluster ◽  
Stellar Population ◽  
Near Infrared ◽  
Local Group ◽  
Stellar Populations ◽  
Age Dating ◽  
Early Type ◽  
Optical Photometry ◽  
Star Forming ◽  
Optical Images

Globular cluster (GC) systems are powerful probes to study the evolutionary histories of galaxies, being tracers of major star fomation episodes (Brodie & Strader 2006). They are found around all major galaxies and are easy to see far beyond the local group. Age dating GCs therefore helps pinpoint epochs of major star forming events. Spectroscopic age dating though (Strader et al. 2005) is extremely time consuming and can only access the few brightest clusters. An alternative is to combine near-infrared (NIR) and optical photometry, and therefore have a better chance in lifting the age metallicity degeneracy than with optical colours alone. This approach relies in testing GC colours against simple stellar population (SSP) models. The first studies following this technique showed the possible existence of a high percentage of intermediate age (2-3 Gyrs) GCs in early-type galaxies known to contain old stellar populations from integrated light studies. Two strong cases can be listed: NGC 4365 (Puzia et al. 2002, Larsen et al. 2005) and NGC 5846 (Hempel et al. 2003). In the present study we combine NIR deep photometry obtained with the WHT/LIRIS instrument and archival HST/ACS optical images to determine g(F475W), z(F840LP) and K(2.2m) magnitudes and colours of GCs in 14 early-type galaxies.

scholarly journals Probing the circumnuclear stellar populations of starburst galaxies in the near-infrared

2014 ◽  
Vol 443 (2) ◽  
pp. 1754-1778 ◽  
Author(s):  
N. Z. Dametto ◽  
R. Riffel ◽  
M. G. Pastoriza ◽  
A. Rodríguez-Ardila ◽  
J. A. Hernandez-Jimenez ◽  
...  
Keyword(s):  
Near Infrared ◽  
Stellar Populations ◽  
Starburst Galaxies

scholarly journals H ii regions in the CALIFA survey: I. catalogue presentation

2020 ◽  
Vol 494 (2) ◽  
pp. 1622-1646 ◽  
Author(s):  
C Espinosa-Ponce ◽  
S F Sánchez ◽  
C Morisset ◽  
J K Barrera-Ballesteros ◽  
L Galbany ◽  
...  
Keyword(s):  
Stellar Populations ◽  
Spectroscopic Properties ◽  
Emission Lines ◽  
H Ii Regions ◽  
Ionized Gas ◽  
New Approach ◽  
Integral Field Spectroscopy ◽  
Diffuse Ionized Gas ◽  
Spectroscopic Information ◽  
Selection Of

ABSTRACT We present a new catalogue of H ii regions based on the integral field spectroscopy (IFS) data of the extended CALIFA and PISCO samples. The selection of H ii regions was based on two assumptions: a clumpy structure with high contrast of H α emission and an underlying stellar population comprising young stars. The catalogue provides the spectroscopic information of 26 408 individual regions corresponding to 924 galaxies, including the flux intensities and equivalent widths of 51 emission lines covering the wavelength range between 3745 and 7200 Å. To our knowledge, this is the largest catalogue of spectroscopic properties of H ii regions. We explore a new approach to decontaminate the emission lines from diffuse ionized gas contribution. This diffuse gas correction was estimated to correct every emission line within the considered spectral range. With the catalogue of H ii regions corrected, new demarcation lines are proposed for the classical diagnostic diagrams. Finally, we study the properties of the underlying stellar populations of the H ii regions. It was found that there is a direct relationship between the ionization conditions on the nebulae and the properties of stellar populations besides the physicals condition on the ionized regions.

scholarly journals Planetary Nebulae in Local Group Galaxies

1983 ◽  
Vol 103 ◽  
pp. 443-460
Author(s):  
Holland C. Ford
Keyword(s):  
Local Group ◽  
Planetary Nebulae ◽  
Stellar Populations ◽  
Chemical Compositions ◽  
H Ii Regions ◽  
Helium Abundance ◽  
Abundance Gradient ◽  
Star Forming ◽  
Ic 10 ◽  
Ngc 6822

Recent surveys for planetary nebulae have given the first identifications in Fornax, NGC 6822, M33, IC 10, Leo A, Sextans A, Pegasus, WLM, NGC 404, and M81, and extended the identifications in the SMC, the LMC, and M31. Observations of planetaries have established chemical compositions in old or intermediate age populations in 8 Local Group galaxies. The chemical compositions show that i) the helium abundance is higher in planetary nebulae than in H II regions in the same galaxy, and ii) nitrogen is overabundant relative to H II regions by factors of 4 to 100. Planetary nebulae are not a major source of helium in star-forming galaxies, and are a major source of nitrogen. The planetary in Fornax has a relatively high O abundance, and, together with Fornax's carbon stars, establishes the presence of at least 2 stellar populations. The abundance gradient derived from 3 planetaries in M31 is very shallow, and gives high abundances at ~ 20 kpc. By using planetary nebulae as standard candles, upper and lower distance limits have been set for 10 Local Group candidates, and a new distance estimated for M81.

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