scholarly journals 2.1. ISOCAM CVF observations of the Quintuplet and Object#17 clusters near the galactic center. diffuse components

1998 ◽  
Vol 184 ◽  
pp. 59-60
Author(s):  
T. Nagata ◽  
K. Kawara ◽  
T. Onaka ◽  
Y. Kitamura ◽  
H. Okuda
Keyword(s):  
Emission Line ◽  
Galactic Center ◽  
Star Clusters ◽  
The Other ◽  
Spectral Features ◽  
Diffuse Emission ◽  
Central Parsec ◽  
Absorption Features

There are two star clusters near the Galactic Center which might be similar to the central parsec cluster. One is the Quintuplet cluster at (l = 0.16°, b = −0.06°), and the other is the Object #17 cluster at (l = 0.12°, b = 0.02°). The Quintuplet, first found in a polarimetric survey by Kobayashi et al. (1983), includes five very bright stars whose color temperatures are in the range of 600-900K (Okuda et al. 1990; Nagata et al. 1990). Object #17 is a cluster of emission line stars (Nagata et al. 1993, 1995; Cotera et al. 1996; Morris & Serabyn 1996). Spectral features of these two objects observed with the ISOCAM (Kessler et al. 1996; Cesarsky et al. 1996) have been reported (Nagata et al., 1996); absorption features due to O-H (2.8μm) CO2(4.3μm), and CO (4.7μm) are present. In this paper, we report diffuse emission components detected in these two fields.

scholarly journals CO and OH in the Galactic Center Region

1980 ◽  
Vol 87 ◽  
pp. 111-112
Author(s):  
Junji Inatani ◽  
Nobuharu Ukita
Keyword(s):  
Emission Line ◽  
Intensity Ratio ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Point Of View ◽  
The Other ◽  
Kinetic Temperature ◽  
Two Dimensional ◽  
Center Region ◽  
Dimensional Distribution

The two-dimensional distribution of molecular clouds in the galactic center region has been investigated in the CO 115 GHz line and in the OH 1665 and 1667 MHz lines. As the former is an emission line, we can find molecular clouds without the unavoidable bias to continuum sources which is inherent in a survey of OH absorption lines. Because the CO line is usually optically thick, the brightness temperature of the line is directly related to the kinetic temperature of the cloud. On the other hand, the real optical depth of the OH line can be obtained from the intensity ratio between 1665 and 1667 MHz lines (assuming LTE). From this point of view we have compared the CO and OH observational results.

scholarly journals The Environmental Effect of the CMF in the Galactic Center 50 km s−1 Molecular Cloud

2012 ◽  
Vol 8 (S292) ◽  
pp. 114-114
Author(s):  
Masato Tsuboi ◽  
Atsushi Miyazaki
Keyword(s):  
Emission Line ◽  
Molecular Cloud ◽  
Environmental Effect ◽  
Galactic Center ◽  
Power Laws ◽  
Statistical Properties ◽  
The Other ◽  
Size Spectrum ◽  
Other Hand ◽  
Sgr A

AbstractWe present the statistical properties of molecular clumps in the Galactic center 50 km s−1 molecular cloud based on observations of the CS J = 1 − 0 emission line with the Nobeyama Millimeter Array. The CMF and size spectrum for the whole cloud can be described by power laws of dN/dM ∝ M−2.6 ± 0.1 and dN/dR ∝ R−5.9±0.3, respectively. The CMF observed in the interacting part with the Sgr A East steepens to dN/dM ∝ M−4.0±0.2. On the other hand, the interaction presumably truncates the size spectrum on the larger side of R ∼ 0.4 pc.

scholarly journals Star Clusters in Quasars: Bloated Stars as Broad Emission Line Clouds

1989 ◽  
Vol 134 ◽  
pp. 137-138
Author(s):  
R. C. Puetter
Keyword(s):  
Black Hole ◽  
Emission Line ◽  
Star Clusters ◽  
Hole Formation ◽  
Line Radiation ◽  
Black Hole Formation ◽  
Broad Emission ◽  
Broad Emission Line

Many scenarios of the evolution of star clusters in the centers of galaxies involve the formation of a central supermassive object. Since black hole formation is not 100% efficient in mass usage, stars are left over. This paper investigates the properties of such stars and proposes that their externally heated atmospheres become “bloated” due to radiative forces from trapped line radiation. Such stars would swell to many times their normal diameters and acquire densities, sizes, and mean column masses typical of QSO/AGN emission line clouds (ELCs).

scholarly journals A Comparison of Near Infrared Spectra of the Galactic Center He I Emission Line Sources and Early Type Mass Losing Stars

1996 ◽  
Vol 169 ◽  
pp. 225-230
Author(s):  
R. D. Blum ◽  
D. L. Depoy ◽  
K. Sellgren
Keyword(s):  
Emission Line ◽  
Infrared Spectra ◽  
Near Infrared ◽  
Galactic Center ◽  
Early Type ◽  
Near Infrared Spectra ◽  
Wide Range ◽  
Comparison Stars ◽  
Band Spectra ◽  
Type Mass

We have obtained R ≈ 570 resolution K band spectra of eight sources in the Galactic Center, including four sources within the IRS 16 cluster, IRS 13, IRS 1W, and the compact He I emission line sources AF (also known as AHH) and AHH NW. We have also obtained R ≈ 570 H and K band spectra of nine galactic and LMC early–type mass–losing stars, including Ofpe/WN9 and WN stars. The spectra of both the Galactic Center sources and the comparison stars show a wide range of behavior in the He I (1.70 μm, 2.06 μm, 2.11 μm) and H I (Brackett series) lines. We find significantly larger He I equivalent widths in the AF source and two galactic early type mass losing stars than in any of the LMC stars. Several of the Galactic Center He I sources are found to have higher He I velocity widths than any of the galactic or LMC early type mass losing stars. At least one source, IRS 13, shows a strong red wing to the He I 2.06 μm emission.

scholarly journals Energy distribution in globular star clusters

1964 ◽  
Vol 20 ◽  
pp. 358-370
Author(s):  
L. H. Aller ◽  
D. J. Faulkner
Keyword(s):  
Energy Distribution ◽  
Spectral Range ◽  
Globular Clusters ◽  
Broad Band ◽  
Star Clusters ◽  
The Other ◽  
Energy Distributions ◽  
Single Observation ◽  
Band Pass ◽  
Time Required

The present investigation is concerned with the energy distributions in globular clusters. In a sense, energy-distribution measurements are comparable with multi-colour photometry. The chief advantage is that narrower band-passes may be used and the entire spectrum traced, whereas in multi-colour photometry one is limited to effective wavelengths determined by the filter and a rather broad band-pass. On the other hand, broad band-pass photometry often permits one to cover a broader spectral range, and to work much faster. Since the time required for a single observation is much shorter, the observer is less at the mercy of the sky transparency. Hence a greater accuracy can be obtained.

scholarly journals The Globular Cluster System of M31

2002 ◽  
Vol 207 ◽  
pp. 38-45
Author(s):  
P. Jablonka
Keyword(s):  
Globular Cluster ◽  
Star Clusters ◽  
Cluster System ◽  
The Other ◽  
Current Status ◽  
The Subject ◽  
Globular Cluster System

This review presents the current status of our knowledge of M31 star clusters. Given the broadness of the subject, I chose to focus on some of its aspects which are not covered by the other participants in this conference.

scholarly journals Mid-Infrared (4.8–12.4 and 20.0 μm) Imaging of the Galactic Center: Modeling the Dust Emission and Energetics of the Central Parsec

1996 ◽  
Vol 169 ◽  
pp. 231-240 ◽  
Author(s):  
Dan Gezari ◽  
Eli Dwek ◽  
Frank Varosi
Keyword(s):  
Galactic Center ◽  
Dust Emission ◽  
Infrared Emission ◽  
Mid Infrared ◽  
New Model ◽  
Central Engine ◽  
Direct Indication ◽  
Sgr A ◽  
Central Parsec ◽  
Array Camera

We have modeled the mid-infrared emission from the Galactic Center using our array camera images at eight wavelengths. The results suggest that the high infrared luminosity of the region is provided by a cluster of luminous stars. There is no direct indication in the new model results of a very luminous object or “central engine” near Sgr A∗.

Radiative wind from a luminous star cluster

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Jun Fukue
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Center ◽  
Star Clusters ◽  
Galactic Nuclei ◽  
Source Distribution ◽  
Radiative Force ◽  
Mass Reduction ◽  
Central Mass ◽  
Point Analysis ◽  
Thermally Driven

Abstract We reexamine the steady spherical wind from distributed sources, such as star clusters and a galactic center, taking into account the radiative force from distributed sources and mass reduction via orbital motions. We consider a cold dusty wind, an isothermal gaseous flow, and a nonisothermal general one without/with a central mass and a stagnation radius for various powers of source distributions. We perform singular point analysis for each case, and obtain a transonic solution, if one exists. We find that thermally driven outflows can emerge in limited situations, such that the source distribution is rather steep in the isothermal flow. On the other hand, under the appropriate conditions radiatively driven winds can easily be produced. Radiative cluster winds without a central mass could emerge from newly born star clusters or neutron star clusters, whereas those with a central mass could appear from active galactic nuclei. Radiative cluster winds would also operate in first star clusters.

scholarly journals The Nature and Origin of Structure in Broad Emission Line Profiles

1997 ◽  
Vol 159 ◽  
pp. 193-194 ◽  
Author(s):  
C. Martin Gaskell ◽  
Stephanie A. Snedden
Keyword(s):  
Emission Line ◽  
The Other ◽  
Central Component ◽  
Balmer Line ◽  
Line Profiles ◽  
Broad Emission ◽  
Broad Emission Line

AbstractWe postulate that all structure in broad lines can be explained by a central component (at the systemic redshift) and the addition of two ‘displaced components’, one blueshifted and the other redshifted. We have been able to successfully classify all Balmer-line profiles on this basis. 3C 390.3-type objects are merely examples where the shifts of the displaced components are unusually large. We believe that the displaced peaks are less prominent in the UV lines because the higher ionization lines are broader.

Arp 70: an interacting galaxy with extreme outflows

2020 ◽  
Vol 493 (1) ◽  
pp. 1434-1446
Author(s):  
A Camps-Fariña ◽  
J E Beckman ◽  
J Font ◽  
I del Moral-Castro ◽  
S F Sanchez ◽  
...  
Keyword(s):  
Emission Line ◽  
The Other ◽  
Spectral Signature ◽  
Main Peak ◽  
Physical Parameters ◽  
Line Profiles ◽  
Public Repository ◽  
Line Region ◽  
Fabry Perot ◽  
H Ii Region

ABSTRACT We analysed a Fabry–Pérot (FP) cube of the interacting pair of galaxies Arp 70, which was obtained from the CeSAM public repository of FP data. On the larger galaxy Arp 70b, we detected the spectral signature of two different outflows, one located in the centre and the other associated with a giant H ii region in the arm region. The central outflow is especially prominent, with the flux of the secondary peaks in the emission-line profiles due to the outflowing gas being similar to that of the main peak. We used an archive fibre spectrum from SDSS to confirm this detection in H α as well as in the [N ii] line and, in addition, to perform diagnostics on the nature of the ionization. The emission at the centre is consistent with a low-ionization nuclear emission-line region and a weak active galactic nucleus. Using the spatial distribution of the profiles in the FP cube, we estimated the shape of the outflow which is consistent with two cones of expanding material, one approaching and the other receding from us, and used this to estimate the physical parameters of the outflow, finding energies of order 1057 erg and masses of order 108 M⊙. On the giant H ii region, we found a very large expanding superbubble with a diameter of ∼5 kpc. The bubble has an energy of order 1054 erg and a mass of about 4 × 107 M⊙. We discuss the possible origins for both of these features and whether they could be associated with the interaction between the galaxies.

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