scholarly journals NIR Line Observations of Starburst Galaxies

1999 ◽  
Vol 186 ◽  
pp. 286-286
Author(s):  
H. Sugai ◽  
M.A. Malkan ◽  
M.J. Ward ◽  
R.I. Davies ◽  
I.S. McLean
Keyword(s):  
Line Emission ◽  
Starburst Galaxies ◽  
Emission Lines ◽  
Ionized Gas ◽  
The Galaxy ◽  
Component C ◽  
Band Spectra ◽  
Marginal Detection ◽  
The Continuum ◽  
K Band

We have obtained images of the H2and Brγ emission lines in the galaxy interacting system NGC 3690 + IC 694. We have also obtained simultaneous H- and K-band spectra for three of its 2μm continuum peaks. The most detectable line emission is concentrated at the continuum peaks. Therefore, the emission lines as well as stellar absorption lines can be used as tracers of the activity in the nuclei themselves. From the strong Brγ and marginal detection of Br10 at the nucleus of IC 694, we derive a large extinction for the fully ionized gas in this nucleus. If we adopt this extinction also for the [Fe II]1.64μm emission, the extinction-corrected [Fe II]1.64μm/Brγ ratio will lie at the higher end of starburst galaxies, and is typical for AGNs or AGN/starburst composites. This might imply that many SNRs are involved in the starburst at this nucleus, unless it includes an AGN. All of our results for Component C, including very little CO absorption in the K band, a largeEW(Brγ), a small H2/Brγ ratio, the effective temperature (Teff≃ 40,000K) derived from HeI 1.70μm/Br10 and HeI 2.06μm/Brγ, are consistent with a very young starburst.

scholarly journals Dissecting the EUV Spectrum of Capella

1996 ◽  
Vol 152 ◽  
pp. 105-112 ◽  
Author(s):  
Nancy S. Brickhouse
Keyword(s):  
Extreme Ultraviolet ◽  
Emission Measure ◽  
Continuous Distribution ◽  
Line Emission ◽  
Local Maximum ◽  
Abundance Ratio ◽  
Emission Lines ◽  
Cool Star ◽  
The Individual ◽  
The Continuum

Extreme ultraviolet spectra of Capella, obtained at various orbital phases over the past two years by the EUVE satellite, show strong emission lines from a continuous distribution of temperatures (~ 105 − 107.3 K). In addition to the strong He II λ303.8, the spectra are dominated by emission lines of highly ionized iron. Strong lines of Fe IX, XV, XVI, and XVIII–XXIV are used to construct emission measure distributions for the individual pointings, which show several striking features, including a minimum near 106 K and a local maximum at 106.8 K. Furthermore, intensities of the highest temperature lines (Te > 107 K) show variations (factors of 2–3) at different orbital phases, while the lower temperature Fe lines show variations of about 30% or less. The low variability of most of the strong low temperature features motivates a detailed analysis of the summed spectrum. With ~ 280 ks of total exposure time, we have measured over 200 emission features with S/N ≥ 3.0 in the summed spectrum. We report here initial results from the analysis of this spectrum. We can now identify lines of Fe VIII and X–XIV, as well as a number of electron density and abundance diagnostic lines.We also report here the first direct measurement of the continuum flux around ~ 100 Å in a cool star atmosphere with EUVE. The continuum flux can be predicted from the emission measure model based on Fe line emission, and demonstrates that the Fe/H abundance ratio is close to the solar photospheric value.

scholarly journals Longslit spectroscopy of the peculiar Seyfert 2 galaxy HRG 10103

2010 ◽  
Vol 6 ◽  
pp. 11-16
Author(s):  
Paulo C.R. Poppe ◽  
Vera A.F. Martin ◽  
Max Faúndez-Abans ◽  
Mariângela De Oliveira-Abans ◽  
Iranderly F. De Fernandes
Keyword(s):  
Spectroscopic Data ◽  
Rotation Curve ◽  
Abundance Ratio ◽  
Emission Lines ◽  
Physical Parameters ◽  
Narrow Line ◽  
Optical Range ◽  
Peculiar Galaxy ◽  
The Galaxy ◽  
The Continuum

We present the rst optical longslit spectroscopy for the galaxy HRG 10103, an Sa(r) type peculiar galaxy seen face-on with an asymmetrical elliptical structure. The main goal of this work is to provide the spectral classication of the current object using the `traditional' diagnostic diagrams. However, we also present a diagnostic involving the known emission line ratio R23, usually used to estimate the O/H abundance ratio. The idea is to make a better distinction between the narrow-line AGNs and the H II galaxies. The spectra were obtained in two observatories (OPD-LNA/MCT and Gemini-South) and includes some of the most important emission lines for ionization diagnostic. Based on the observed spectra, HRG 10103 is a Seyfert 2 galaxy with typical line-ratios values in the optical range. We have estimated nuclear redshift of z = 0.039. The resulting reddening values as a function of distance from the nucleus are presented too. The errors in the  fluxes were mostly caused by uncertainties in the placement of the continuum level. The rotation curve is typical of spiral disks, rising shallowly and  attening at an observed amplitude of about 200 km s^(-1). Some other physical parameters have been derived whenever possible. The spectroscopic data reduction was carried out using the GEMINI.GMOS package as well as the standard IRAF procedures.

Optical spectroscopy of radio jets in 3C 31, 3C 75, 3C 83.1B, and 3C 465

1986 ◽  
Vol 64 (4) ◽  
pp. 369-372 ◽  
Author(s):  
Christopher P. O'Dea ◽  
Frazer N. Owen ◽  
William C. Keel
Keyword(s):  
Optical Spectroscopy ◽  
External Medium ◽  
Line Emission ◽  
Radio Sources ◽  
Ionized Gas ◽  
Radio Jets ◽  
Upper Limits ◽  
The Galaxy ◽  
Lower Limits ◽  
Total Velocity

We present preliminary results of optical spectroscopy of four radio galaxies with jets (3C 75, 3C 465, 3C 31, and 3C 83. 1B (NGC 1265)). We examined selected regions in and around the radio jets for evidence of the interaction of the jets with their external medium (e.g., entrainment or bending through collision with clouds). We searched for the emission lines expected from ionized gas at a temperature of T ~ 104 K (e.g., Hα and [NII]) as well as those expected at higher temperatures (T ~ 106 K, Fe X (λ6374) and Fe XIV (λ5303)).We found no extranuclear emission in the regions searched in 3C 75, 3C 465, and 3C 83.1B. Assuming values for the pressure in the environment of the radio sources, we found the upper limits to the line emission correspond to model-dependent lower limits to the temperature in the range T ≥ 1.5–3 × 106 K and upper limits to the electron density in the range ne ≤ 5 × 10−2−5 × 10−3 cm−3.In 3C 31, we detected extended Hα and [NII] emission that is peaked on the nucleus and exhibits a velocity gradient. The [NII] emission has a total velocity width of ~800 km∙s−1. It is not yet clear whether any of this emission is associated with the jet (e.g., entrained gas) or whether it is associated with a known dust lane in the galaxy NGC 383.

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 Discovery of Molecular-line Polarization in the Disk of TW Hya

2021 ◽  
Vol 922 (2) ◽  
pp. 139
Author(s):  
Richard Teague ◽  
Charles L. H. Hull ◽  
Stéphane Guilloteau ◽  
Edwin A. Bergin ◽  
Anne Dutrey ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Line Emission ◽  
Emission Lines ◽  
Continuum Emission ◽  
Azimuthal Dependence ◽  
Molecular Line ◽  
Polarization Fraction ◽  
Co Emission ◽  
Higher Sensitivity ◽  
The Continuum

Abstract We report observations of polarized line and continuum emission from the disk of TW Hya using the Atacama Large Millimeter/submillimeter Array. We target three emission lines, 12CO (3–2), 13CO (3–2), and CS (7–6), to search for linear polarization due to the Goldreich–Kylafis effect, while simultaneously tracing the continuum polarization morphology at 332 GHz (900 μm), achieving a spatial resolution of 0.″5 (30 au). We detect linear polarization in the dust continuum emission; the polarization position angles show an azimuthal morphology, and the median polarization fraction is ∼0.2%, comparable to previous, lower frequency observations. Adopting a “shift-and-stack” technique to boost the sensitivity of the data, combined with a linear combination of the Q and U components to account for their azimuthal dependence, we detect weak linear polarization of 12CO and 13CO line emission at a ∼10σ and ∼5σ significance, respectively. The polarization was detected in the line wings, reaching a peak polarization fraction of ∼5% and ∼3% for the two molecules between disk radii of 0.″5 and 1″. The sign of the polarization was found to flip from the blueshifted side of the emission to the redshifted side, suggesting a complex, asymmetric polarization morphology. Polarization is not robustly detected for the CS emission; however, a tentative signal, comparable in morphology to that found for the 12CO and 13CO emission, is found at a ≲3σ significance. We are able to reconstruct a polarization morphology, consistent with the azimuthally averaged profiles, under the assumption that this is also azimuthally symmetric, which can be compared with future higher-sensitivity observations.

scholarly journals A 5.5–35 μm Spectral Analysis of Active Galactic Nuclei

2009 ◽  
Vol 5 (S267) ◽  
pp. 137-137
Author(s):  
D. A. Sales ◽  
M. G. Pastoriza ◽  
R. Riffel
Keyword(s):  
Spectral Analysis ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Spectroscopic Properties ◽  
Starburst Galaxies ◽  
Emission Lines ◽  
Raw Data ◽  
Mid Infrared ◽  
Infrared Wavelengths ◽  
The Continuum

The spectroscopic properties of a sample of nine Seyfert 1, six NLS1, 26 Seyfert 2, and three starburst galaxies have been studied at mid-infrared wavelengths in order to determine if the frequency of detection of the brightest emission lines and the continuum shape are correlated with the degree of activity. The raw data were obtained from the Spitzer Infrared Spectrograph (IRS) archive and reduced with the pipeline (version 17.2). The spectra of the galaxies were grouped by type of activity. We conclude through this study that in general the continuum shape of the active galactic nuclei (AGN) is flat between 5 μm and 12 μm, and strong variations are found at longer wavelengths in this sample.

scholarly journals Fabry-Perot Observations of Cen A

1987 ◽  
Vol 127 ◽  
pp. 419-420
Author(s):  
J.J.E. Hayes ◽  
R.A. Schommer ◽  
T.B. Williams
Keyword(s):  
Velocity Dispersion ◽  
Line Emission ◽  
Emission Lines ◽  
Peculiar Galaxy ◽  
Fabry Perot ◽  
Construct Maps ◽  
The Continuum

We present Fabry–Perot spectrophotometry of the well-known peculiar galaxy Cen A (NGC 5128). The observations were carried out using the Rutgers Fabry–Perot system and a CCD as a detector. We scanned the Hα and [NII] (λ6583) emission lines. From these data we were able to construct maps of the continuum, line emission, velocity and velocity dispersion. The velocity maps in both Hα and [NII] have smooth gradients and twists in the line of nodes. The deprojected emission maps strongly resemble emission maps of face-on spirals. We speculate that Cen A is a merger between an elliptical and a spiral.

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.

scholarly journals Microlensing Induced Spectral Variability In Q2237+0305

1996 ◽  
Vol 173 ◽  
pp. 241-246
Author(s):  
Geraint F. Lewis ◽  
Mike J. Irwin ◽  
Paul C. Hewett
Keyword(s):  
Emission Line ◽  
Line Emission ◽  
Emission Lines ◽  
Broad Line ◽  
Spectral Variability ◽  
Broad Emission ◽  
Quasar Spectra ◽  
Line Region ◽  
Broad Emission Line ◽  
The Continuum

The degree of microlensing induced amplification is dependent upon the size of a source. As quasar spectra consist of the sum of emission from different regions this scale dependent amplification can produce spectral differences between the images of a macrolensed quasar. This paper presents the first direct spectroscopic evidence for this effect, providing a limit on the scale of the continuum and the broad line emission regions at the center of a source quasar (2237+0305). Lack of centroid and profile differences in the emission lines indicate that substructure in the broad emission line region is > 0.05 parsecs.

scholarly journals The Evolution of QSO Spectra: Evidence for Microlensing?

1996 ◽  
Vol 173 ◽  
pp. 289-290
Author(s):  
Paul J. Francis ◽  
Anuradha Koratkar
Keyword(s):  
Equivalent Width ◽  
High Redshift ◽  
Line Emission ◽  
Compact Objects ◽  
Emission Lines ◽  
Continuum Emission ◽  
The Continuum

We find that the spectra of QSOs evolve: high redshift QSOs (z > 1.5) have lower equivalent width emission lines than low redshift QSOs (z < 0.5) with the same luminosities and radio properties.We propose that microlensing by compact objects may account for the apparent evolution. If Ω ∼ 0.05 in compact objects, the continuum emission from many high redshift QSOs will be amplified, but not the line emission, leading to the observed decrease in the apparent equivalent widths.

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