The Hot Molecular Core of G12.21–0.10: NH3(4, 4) Observations

2009 ◽  
Vol 5 (S262) ◽  
pp. 319-320
Author(s):  
Eduardo de la Fuente ◽  
Stanley E. Kurtz ◽  
Carlos A. Rodriguez-Rico ◽  
Miguel A. Trinidad ◽  
Esteban Araya ◽  
...  
Keyword(s):  
Spatial Location ◽  
Forthcoming Paper ◽  
Radio Continuum ◽  
Ionized Gas ◽  
Compact Structure ◽  
Hii Region ◽  
Molecular Core ◽  
Molecular Lines ◽  
First Time ◽  
Ultracompact Hii

AbstractIn de la Fuente (2007; Ph. D. Thesis), the molecular clump associated with the ultracompact HII region G12.21–0.10 was confirmed as a large, hot, dense Hot Molecular Core nearby to the ionized gas. The density was confirmed by comparing low resolution NH3(2, 2) and (4, 4) VLA observations, with other molecular lines and radio–continuum observations. These results will be presented in detail in a forthcoming paper (de la Fuente et al. in preparation). In these works, for the first time, the spatial location of the Hot Molecular Core is presented. Here we present the NH3(4,4) observations from de la Fuente (2007; Ph. D. Thesis), confirming that the hotter and denser gas in the molecular core lies in a compact structure, of smaller scale than the NH3(2, 2) emission.

scholarly journals G305.20+0.21: A very young class II methanol maser source

2002 ◽  
Vol 206 ◽  
pp. 155-158
Author(s):  
Andrew J. Walsh
Keyword(s):  
Detection Limit ◽  
Class Ii ◽  
Radio Continuum ◽  
Radio Flux ◽  
Infrared Source ◽  
Hii Region ◽  
Methanol Maser ◽  
Upper Limits ◽  
Ultracompact Hii

Sensitive radio continuum observations of G305.20+0.21 are performed to look for evidence of an ultracompact HII region. None is found at either 8.64 or 4.8GHz above a 5σ detection limit of about 0.25mJy in both cases. Since G305.20+0.21 is such a bright infrared source, there is a large discrepancy between the expected radio flux and the observed upper limits. This is interpreted as evidence that G305.20+0.21 is a massive protostar traced by a methanol maser site.

scholarly journals 4.4. The Sagittarius C region mapped in CS(2→1) and (3→2) by the IRAM 30m telescope

1998 ◽  
Vol 184 ◽  
pp. 173-174
Author(s):  
C. Kramer ◽  
J. Staguhn ◽  
H. Ungerechts ◽  
A. Sievers
Keyword(s):  
Spatial Resolution ◽  
Radio Telescope ◽  
Molecular Cloud ◽  
High Spatial Resolution ◽  
Ionized Gas ◽  
Hii Region ◽  
Molecular Material ◽  
Giant Molecular Cloud ◽  
First Time

We study the interaction of a dense giant molecular cloud with the HII region Sagittarius C, and a prominent nonthermal filament (NTF). For this purpose, we mapped the CS(2→1) and (3→2) transitions simultaneously with the IRAM 30m radio telescope, using the on-the-fly observing mode, and covering a 20pc×37pc (8′ × 15′) region. The high spatial resolution, 0.7pc (16″) at 147 GHz, allows for the first time to analyze in detail the morphology and kinematics of the molecular material and its relation to the ionized gas.

The Marseille Observatory Hα Survey: Comparisons by CO, 6 CM and IRAS Data

1998 ◽  
Vol 179 ◽  
pp. 186-188
Author(s):  
D. Russeil ◽  
P. Amram ◽  
Y.P. Georgelin ◽  
Y.M. Georgelin ◽  
M. Marcelin ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Large Scale ◽  
Galactic Plane ◽  
Photon Counting ◽  
Hii Regions ◽  
Radio Continuum ◽  
Line Of Sight ◽  
Ionized Gas ◽  
Hii Region ◽  
Pattern Determination

The Marseille Observatory Hα survey supplies Hα velocities of the ionized hydrogen over large zones of the sky towards the galactic plane. This survey, led at the ESO La Silla, uses a 36 cm telescope equiped with a scanning Fabry-Perot interferometer and a photon counting camera (Le Coarer et al. 1992). About 250 fields (39′×39′) toward the galactic plane have already been covered (see Figure 1) with a spatial resolution of 9″×9″ and a spectral resolution of 5 km s–1. This allows us to observe the discrete HII regions and the diffuse ionized gas widely distributed between them and to separate the distinct layers found along the line of sight. HII regions are often grouped on the molecular cloud surface, then CO, radio continuum and recombination lines surveys of the galactic plane are also essential to distinguish the HII region-molecular cloud complexes met on the line of sight, and in order to take dynamical effects into account, such as the champagne effect, for the kinematic distance determination. Indeed, the spiral structure pattern determination requires avoiding any artificial spread by clearly identifying the giant complexes composed of molecular clouds, HII regions, diffuse ionized hydrogen widely surrounding them, and exciting stars. On the other hand the ionized gas data (Hα and recombination lines) associated with IRAS data help us to study the nature of the young objects constituent of these complexes and to assess their detectability. We present two fields from the Hα survey and parallel large scale investigations.

scholarly journals A Spectral Line Survey of IRAS 17470-2853 from 86.1 to 92.1 GHz

2002 ◽  
Vol 19 (4) ◽  
pp. 505-514 ◽  
Author(s):  
Hun-Dae Kim ◽  
Ramesh Balasubramanyam ◽  
Michael G. Burton
Keyword(s):  
Spectral Line ◽  
Line Width ◽  
Thermal Emission ◽  
Frequency Range ◽  
Hii Region ◽  
Significant Difference ◽  
Molecular Lines ◽  
Line Survey ◽  
Simple Molecules ◽  
Ultracompact Hii

AbstractWe present results from a spectral line survey of the young stellar object IRAS 17470-2853, undertaken to examine chemical changes during the evolution from hot molecular cores to ultracompact HII regions. Observations were carried out with the Mopra 22 m radio telescope in the frequency range from 86.1 to 92.1 GHz. A total of 21 lines from 9 molecules were detected. Except for CH3CN they are all simple molecules. We compare the results to the ultracompact HII region G34.3+0.15, where spectral line surveys in the frequency range 80–115 GHz and 330–360 GHz have been performed. While the molecular lines detected are similar, their widths and intensities are somewhat narrower and lower, respectively, in IRAS 17470-2853. The typical line width of ˜5 km s−1 indicates relatively quiet or quasi-thermal emission. On the other hand, a significant difference in TA* (HNC)/TA*(HCN) has been found: 0.8 for IRAS 17470-2853 compared to 2.6 for G34.3+0.15. The broad line width of SiO (υ=0, J=2–1), ˜9 km s−1, suggests that IRAS 17470-2853 is experiencing a shock generated by the embedded object. Column densities, or lower limits to them, are derived for observed molecules.

scholarly journals Mid-Ir Emission of Low-Metallicity Galaxies

1998 ◽  
Vol 11 (1) ◽  
pp. 113-114
Author(s):  
S. Plante ◽  
M. Sauvage ◽  
D. Kunth
Keyword(s):  
Stellar Content ◽  
Ionized Gas ◽  
Band Ratio ◽  
Hii Region ◽  
Stellar Photometry ◽  
North East ◽  
The North ◽  
Low Metallicity ◽  
Ir Emission ◽  
Exact Origin

NGC 595 is a giant Hɪɪ region located in the western part of the spiral galaxy M 33. It is the second in importance in this galaxy, after NGC 604. At 0.84 Mpc, HST is able to resolve its stellar content. Malumuth et al. (1996) obtained HST UV, U, B and V images of this region and derived an ionizing luminosity of 5 × 1050 phots-1 and an average reddening EB-V = 0.36±0.28 mag. The stars are mostly concentrated in the central part of the region, where little emission of gas is seen (the ionized gas lies more in a shell around the stars, figure 1a). Wilson & Scoville (1993) showed the molecular gas to be situated in the south-east part of the region, just outside of the bright knot of stars. Viallefond et al. (1986) found a reddening gradient in the north-east/south-west direction by observing the Hi gas, which was confirmed by Malumuth et al. (1996) with stellar photometry. We obtained ISO images for NGC 595 in the 5.0 to 8.5 μm range. The emission in this spectral range is dominated by the so-called PAH bands. Current interpretation of these has them originating from stochastically heated molecules. Two of these bands are located in the range observed, at 6.2 μm and 7.7 μm. Stochastic heating implies that the in-band flux is directly proportional to the number of photons absorbed by the molecules. For typical HII regions, Cohen et al. (1989) found 0.58 for the I6.2/I7.7 in-band ratio. However many processes, ionization, dehydrogenation, can modify this ratio. Furthermore, an underlying continuum is present though its exact origin is unknown.

Ionized AGN outflows are less powerful than assumed: A multi-wavelength census of outflows in type II AGN

2019 ◽  
Vol 15 (S356) ◽  
pp. 225-225
Author(s):  
Dalya Baron
Keyword(s):  
Optical Emission ◽  
Infrared Emission ◽  
Type Ii ◽  
Ionized Gas ◽  
Kinetic Coupling ◽  
Mass Outflow ◽  
Multi Wavelength ◽  
Novel Method ◽  
First Time ◽  
Ionization Parameter

AbstractIn this talk I will show that multi-wavelength observations can provide novel constraints on the properties of ionized gas outflows in AGN. I will present evidence that the infrared emission in active galaxies includes a contribution from dust which is mixed with the outflow and is heated by the AGN. We detect this infrared component in thousands of AGN for the first time, and use it to constrain the outflow location. By combining this with optical emission lines, we constrain the mass outflow rates and energetics in a sample of 234 type II AGN, the largest such sample to date. The key ingredient of our new outflow measurements is a novel method to estimate the electron density using the ionization parameter and location of the flow. The inferred electron densities, ∼104.5 cm−3, are two orders of magnitude larger than found in most other cases of ionized outflows. We argue that the discrepancy is due to the fact that the commonly-used [SII]-based method underestimates the true density by a large factor. As a result, the inferred mass outflow rates and kinetic coupling efficiencies are 1–2 orders of magnitude lower than previous estimates, and 3–4 orders of magnitude lower than the typical requirement in hydrodynamic cosmological simulations. These results have significant implications for the relative importance of ionized outflows feedback in this population.

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 Intra-Day Variability Observations of Two Dozens of Blazars at 4.8 GHz

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 15
Author(s):  
Xiang Liu ◽  
Xin Wang ◽  
Ning Chang ◽  
Jun Liu ◽  
Lang Cui ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Forthcoming Paper ◽  
Galactic Latitude ◽  
Local Interstellar Medium ◽  
Bl Lac Objects ◽  
Spectrum Radio ◽  
First Results ◽  
First Time ◽  
Source Structure

Two dozens of radio loud active galactic nuclei (AGNs) have been observed with Urumqi 25 m radio telescope in order to search for intra-day variability (IDV). The target sources are blazars (namely flat spectrum radio quasars and BL Lac objects) which are mostly selected from the observing list of RadioAstron AGN monitoring campaigns. The observations were carried out at 4.8 GHz in two sessions of 8–12 February 2014 and 7–9 March respectively. We report the data reduction and the first results of observations. The results show that the majority of the blazars exhibit IDV in 99.9% confidence level, some of them show quite strong IDV. We find the strong IDV of blazar 1357 + 769 for the first time. The IDV at centimeter-wavelength is believed to be predominately caused by the scintillation of blazar emission through the local interstellar medium in a few hundreds parsecs away from Sun. No significant correlation between the IDV strength and either redshift or Galactic latitude is found in our sample. The IDV timescale along with source structure and brightness temperature analysis will be presented in a forthcoming paper.

scholarly journals Deuteration around the ultracompact HII region Monoceros R2

2014 ◽  
Vol 569 ◽  
pp. A19 ◽  
Author(s):  
S. P. Treviño-Morales ◽  
P. Pilleri ◽  
A. Fuente ◽  
C. Kramer ◽  
E. Roueff ◽  
...  
Keyword(s):  
Hii Region ◽  
Ultracompact Hii

scholarly journals Spatial Location and the State of Timber Industry Enterprises in the Soviet Union by the End of the First Five-Year Plan

2021 ◽  
Vol 22 (3) ◽  
pp. 491-515
Author(s):  
Ivan Zykin
Keyword(s):  
Soviet Union ◽  
Spatial Location ◽  
Timber Industry ◽  
New Economic Policy ◽  
Industry Location ◽  
The Soviet Union ◽  
Forested Areas ◽  
Wood Machining ◽  
First Time ◽  
Made In

In the period of New Economic Policy in the USSR industrialization issues became very topical. In timber industry complex, the solutions were related to the development of forested areas in Northeastern regions of the country as well as to the construction and reconstruction of enterprises. The article provides the first-time analysis of maps and forest industry location, based on the results of the First Five-Year Plan published in the atlas “The Industry in the USSR and the beginning of the Second Five-Year Plan“ and statistical collection materials ”Social Construction of the USSR”. The analysis was made in order to define the situation in the industry, the main directions of production as well as the regional specificities. Using the example of wood machining sphere the author presents the analysis of enterprise groups according to different criteria. The research resulted in conclusions about highest intensity of enterprise reconstruction and construction in timber sawing, in furniture industry and intra-sectoral combination. In timber industry, the majority of enterprises were small and middle companies, which greatly contributed to its development. Regional specificities of timber industry location included concentration of main facilities in northwestern, western and central parts of the country, in the Volga region and in Ural. However only several regions had developed wood machining and deep processing spheres, such as Leningrad oblast, the Gorky Krai, Belarusian and the Ukrainian Soviet Republics.

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