scholarly journals Optical Spectra of Nuclei of Early Type Galaxies

1980 ◽  
Vol 5 ◽  
pp. 193-193
Author(s):  
Gerhard F. O. Schnur ◽  
W. A. Sherwood
Keyword(s):  
Spectral Resolution ◽  
Strong Absorption ◽  
Emission Lines ◽  
Absorption Lines ◽  
Nuclear Region ◽  
Early Type ◽  
Ionized Gas ◽  
Balmer Series ◽  
Weak Absorption ◽  
Normal Galaxies

Early type galaxies classified as SO by Sandage or lenticulars and SO/a appearing in RCBG have been observed with the IDS on the ESO 3.6 m telescope. The slit was 1” × 4” and the spectral resolution was 9 Å from 3900 Å to 7000 Å. Statistics for the first 50 galaxies observed are given.18% of the sample show the [OIII] doublet stronger than Hß; 32% have spectra dominated by the Balmer series progressing from mainly emission through strong absorption series to weak absorption; 20% have only [NII] or [SII] in emission while 30% show absorption lines and bands. That is, 70% show emission lines toward the nuclear region. Among the 50 galaxies, HI at 21 cm has been detected in 21 galaxies: 16 of these show ionized gas to be present. NGC5273 has Seyfert characteristics with strong [OIII]; Hß has a width of ˜1000 kms-1. The low luminosity end of the Seyfert distribution may be found among normal galaxies.

scholarly journals Highly Ionized Gas as a Diagnostic of the Inner NLR

2009 ◽  
Vol 5 (S267) ◽  
pp. 383-386
Author(s):  
M. J. Ward ◽  
J. Mullaney ◽  
C. Jin ◽  
R. Davies
Keyword(s):  
Case Studies ◽  
Spectral Resolution ◽  
Near Infrared ◽  
Emission Lines ◽  
Ionized Gas ◽  
Neutral Species ◽  
Wide Range ◽  
Individual Objects

AbstractThe spectra of AGN, from the ultraviolet to the near infrared, exhibit emission lines covering a wide range of ionization states, from neutral species such as [O i] λ 6300, up to [Fe iv] λ 5303. Here we report on some recent studies of the properties of highly ionized lines (HILs), plus two case studies of individual objects. Future IFU observations at high spatial and good spectral resolution will probe the excitation and kinematics of the gas in the zone between the extended NLR and unresolved BLR. Multi-component SED fitting can be used to link the source of photoionization with the strengths and ratios of the HILs.

scholarly journals The Onset of Quasi-Periodic Variations in Be Stars

1993 ◽  
Vol 134 ◽  
pp. 223-225
Author(s):  
T. Kogure ◽  
M. Mon ◽  
M. Suzuki
Keyword(s):  
Sudden Onset ◽  
Radial Velocities ◽  
Emission Lines ◽  
Absorption Lines ◽  
Close Binaries ◽  
Be Stars ◽  
Early Type ◽  
Stable Period ◽  
Long Term Variations

We present some evidence of the quasi-periodic long-term variations (QPLV) in the violet-to-red ratio of double-peaked emission lines (V/R variation) and/or in the radial velocities of shell absorption lines for some Be stars. Although the V/R variations are rather prevailing phenomena among Be stars, the QPLV is remarkable by the following characteristics: (1)The QPLV appears as a sudden onset of repeated V/R variations after a long (10 years), almost stable period, and it persists for a few or several periods in ten or more years.(2)The period and amplitude of V/R variations change from cycle to cycle and from star to star. The variations of radial velocities (RV) of shell absorption lines are usually nearly parallel with the V/R variations.(3)The QPLV appears usually in early type Be stars with large rotational velocities, regardless whether the stars are normal Be or shell stars, and whether they are close-binaries or single stars.

scholarly journals The binary orbit of HD 92740

1979 ◽  
Vol 83 ◽  
pp. 291-295
Author(s):  
Virpi S. Niemelä
Keyword(s):  
Observational Data ◽  
Orbital Motion ◽  
Radial Velocities ◽  
Emission Lines ◽  
Absorption Lines ◽  
Balmer Series ◽  
Absorption And Emission ◽  
Carina Nebula ◽  
Binary Orbit

HD 92740 is a star located in the Carina nebula showing a Wolf-Rayet spectrum of type WN7. Faint absorption lines of the upper Balmer series of hydrogen, and also of the Pickering series of Hell are present in the spectrum, in addition to the WN emissions. Although absorption lines present in a Wolf-Rayet spectrum are generally assumed to arise in a companion OB star, a previous study (Niemelä 1973) of the radial velocities of HD 92740 showed that the absorption and emission lines followed the same orbital motion. Subsequent spectral observations of this star have been carried out at the Cerro Tololo Inter-American Observatory, Chile, and at the Córdoba Observatory, Argentina, during four years; the observational data are listed in Conti, Niemelä and Walborn (1978). These observations showed that the true period is 8 times longer than the initially derived period of 10 days, and that doubtlessly the absorption lines belong to the WN star.

scholarly journals Outflows in the inner kiloparsec of NGC 1566 as revealed by molecular (ALMA) and ionized gas (Gemini-GMOS/IFU) kinematics

2019 ◽  
Vol 621 ◽  
pp. A83 ◽  
Author(s):  
R. Slater ◽  
N. M. Nagar ◽  
A. Schnorr-Müller ◽  
T. Storchi-Bergmann ◽  
C. Finlez ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Large Scale ◽  
Emission Lines ◽  
Host Galaxy ◽  
Molecular Gas ◽  
Ionized Gas ◽  
Spiral Arms ◽  
Gas Kinematics ◽  
Molecular Outflow ◽  
Outflow Rate

Context. Tracing nuclear inflows and outflows in active galactic nuclei (AGNs), determining the mass of gas involved in them, and their impact on the host galaxy and nuclear black hole requires 3D imaging studies of both the ionized and molecular gas. Aims. We map the distribution and kinematics of molecular and ionized gas in a sample of active galaxies to quantify the nuclear inflows and outflows. Here, we analyze the nuclear kinematics of NGC 1566 via ALMA observations of the CO J:2-1 emission at 24 pc spatial and ∼2.6 km s−1 spectral resolution, and Gemini-GMOS/IFU observations of ionized gas emission lines and stellar absorption lines at similar spatial resolution, and 123 km s−1 of intrinsic spectral resolution. Methods. The morphology and kinematics of stellar, molecular (CO), and ionized ([N II]) emission lines are compared to the expectations from rotation, outflows, and streaming inflows. Results. While both ionized and molecular gas show rotation signatures, there are significant non-circular motions in the innermost 200 pc and along spiral arms in the central kpc (CO). The nucleus shows a double-peaked CO profile (full width at zero intensity of 200 km s−1), and prominent (∼80 km s−1) blue- and redshifted lobes are found along the minor axis in the inner arcseconds. Perturbations by the large-scale bar can qualitatively explain all features in the observed velocity field. We thus favor the presence of a molecular outflow in the disk with true velocities of ∼180 km s−1 in the nucleus and decelerating to 0 by ∼72 pc. The implied molecular outflow rate is 5.6 M⊙ yr−1, with this gas accumulating in the nuclear 2″ arms. The ionized gas kinematics support an interpretation of a similar but more spherical outflow in the inner 100 pc, with no signs of deceleration. There is some evidence of streaming inflows of ∼50 km s−1 along specific spiral arms, and the estimated molecular mass inflow rate, ∼0.1 M⊙ yr−1, is significantly higher than the SMBH accretion rate (ṁ = 4.8 × 10−5 M⊙ yr−1).

scholarly journals Physical Conditions in Radio Galaxies and Quasars

1977 ◽  
Vol 74 ◽  
pp. 183-191
Author(s):  
Donald E. Osterbrock
Keyword(s):  
Emission Line ◽  
Large Fraction ◽  
Radio Galaxies ◽  
Emission Lines ◽  
Ionized Gas ◽  
Strong Emission ◽  
Normal Galaxies ◽  
Physical Conditions ◽  
Early Survey ◽  
Optical Identifications

It is well known from the pioneering work of Baade and Minkowski that radio galaxies very often have strong emission lines in the spectra of their nuclei, indicating the presence of relatively large amounts of ionized gas. For instance, in the early survey of radio galaxies by Schmidt (1965), of the 35 galaxies observed, 32 had at least [0 II] λ3727 in their spectra and well over half had relatively strong [0 II] and other observable emission lines as well. In the recent review of optical identifications and spectroscopy of the revised 3C catalogue of radio sources by Smith et al. (1976), 137 radio galaxies are listed. Of these descriptive spectral information is given for 98, of which 49 show strong–emission line spectra, 19 intermediate–strength emission, 12 weak emission, and 18 a pure absorption–line spectrum without detectable emission lines. The fraction of objects with emission line–spectra is much higher than for normal galaxies. It is thus apparent that though the presence of emission lines is neither a necessary nor a sufficient condition that a galaxy be an observable radio source, nevertheless a large fraction of radio galaxies do contain ionized gas in their nuclei.

The DIVING3D Project: Analysis of the nuclear region of Early-type Galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 454-456
Author(s):  
T. V. Ricci ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Emission Lines ◽  
H Ii Regions ◽  
Sample Type ◽  
Early Type ◽  
Integral Field Spectroscopy ◽  
Project Analysis ◽  
Line Region ◽  
Field Unit ◽  
Integral Field

AbstractIn this work, we present preliminary results regarding the nuclear emission lines of a statistically complete sample of 56 early-type galaxies that are part of the Deep Integral Field Spectroscopy View of Nuclei of Galaxies (DIVING3D) Project. All early type galaxies (ETGs) were observed with the Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) installed on the Gemini South Telescope. We detected emission lines in 93% of the sample, mostly low-ionization nuclear emission-line region galaxies (LINERs). We did not find Transition Objects nor H II regions in the sample. Type 1 objects are seen in ∼23% of the galaxies.

scholarly journals 3D optical spectroscopic study of NGC 3344 with SITELLE: I. Identification and confirmation of supernova remnants

2019 ◽  
Vol 488 (1) ◽  
pp. 803-829 ◽  
Author(s):  
I Moumen ◽  
C Robert ◽  
D Devost ◽  
R P Martin ◽  
L Rousseau-Nepton ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Flux Ratio ◽  
Large Magellanic Cloud ◽  
Emission Lines ◽  
Ionization Mechanism ◽  
H Ii Regions ◽  
Nearby Galaxy ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Diffuse Ionized Gas

ABSTRACT We present the first optical identification and confirmation of a sample of supernova remnants (SNRs) in the nearby galaxy NGC 3344. Using high spectral and spatial resolution data, obtained with the CFHT imaging Fourier transform spectrograph SITELLE, we identified about 2200 emission line regions, many of which are H ii regions, diffuse ionized gas regions, and also SNRs. Considering the stellar population and diffuse ionized gas background, which are quite important in NGC 3344, we have selected 129 SNR candidates based on four criteria for regions where the emission lines flux ratio [S ii]/H α ≥ 0.4. Emission lines of [O ii] λ3727, H β, [O iii] λλ4959,5007, H α, [N ii] λλ6548,6583, and [S ii] λλ6716,6731 have been measured to study the ionized gas properties of the SNR candidates. We adopted a self-consistent spectroscopic analysis, based on Sabbadin plots and Baldwin, Phillips & Terlevich diagrams, to confirm the shock-heated nature of the ionization mechanism in the candidates sample. With this analysis, we end up with 42 Confirmed SNRs, 45 Probable SNRs, and 42 Less likely SNRs. Using shock models, the confirmed SNRs seem to have a metallicity ranging between Large Magellanic Cloud and 2×solar. We looked for correlations between the size of the confirmed SNRs and their emission lines ratios, their galaxy environment, and their galactocentric distance: We see a trend for a metallicity gradient among the SNR population, along with some evolutionary effects.

scholarly journals The ATLAS3D project - X. On the origin of the molecular and ionized gas in early-type galaxies

2011 ◽  
Vol 417 (2) ◽  
pp. 882-899 ◽  
Author(s):  
Timothy A. Davis ◽  
Katherine Alatalo ◽  
Marc Sarzi ◽  
Martin Bureau ◽  
Lisa M. Young ◽  
...  
Keyword(s):  
Early Type ◽  
Ionized Gas

The Deuterium Balmer Series

2005 ◽  
Vol 13 ◽  
pp. 811-812
Author(s):  
Guillaume Hébrard
Keyword(s):  
Spectral Resolution ◽  
Magellanic Clouds ◽  
High Spectral Resolution ◽  
Excitation Mechanism ◽  
Balmer Series ◽  
Detection And Identification ◽  
Balmer Lines ◽  
Low Metallicity ◽  
Resolution Data ◽  
Narrow Emission

AbstractThe first detection and identification of deuterium Balmer lines were recently reported in H ii regions, using high spectral resolution data secured at CFHT and VLT. The Di lines appear as faint, narrow emission features in the blue wings of the H i Balmer lines and can be distinguished from high-velocity Hi emission. The identification as deuterium and the excitation mechanism as fluorescence are both established beyond doubt. The deuterium Balmer series might lead to a new, optical method of deuterium abundance measurement in the interstellar medium. This may be the only way to observe atomic deuterium in objects like the Magellanic Clouds or low metallicity blue compact galaxies.

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