scholarly journals A 158μm [CII] Map of NGC 6946: Detection in Extragalactic Atomic and Ionized Gas

1992 ◽  
Vol 150 ◽  
pp. 117-119
Author(s):  
S. C. Madden ◽  
N. Geis ◽  
R. Genzel ◽  
F. Herrmann ◽  
A. Poglitsch ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Line Emission ◽  
Far Infrared ◽  
Max Planck ◽  
Ionized Gas ◽  
Ob Stars ◽  
Ngc 6946 ◽  
Total Luminosity ◽  
Fabry Perot ◽  
External Galaxies

The first observations of the [CII] line toward the nuclei of gas-rich external galaxies, showed that the far-infrared line emission contributes up to 1% of the total luminosity and most likely originates from dense photon-dominated regions (PDRs) associated with the surfaces of molecular clouds exposed to FUV from external or embedded OB stars (Crawford et al. 1985, Lugten et al. 1986, Stacey et al. 1991). We have mapped the [CII] emission toward NGC 6946 over an 8' × 6' (23 × 17 kpc) (Madden et al. 1991) using the Max-Planck Instutute/U.C.Berkeley Far-Infrared Imaging Fabry-Perot Interferometer (FIFI) on the Kuiper Airborne Observatory (KAO).

scholarly journals Ionization of the Galactic Center Arched Filaments

1989 ◽  
Vol 120 ◽  
pp. 132-133
Author(s):  
R. Rubin ◽  
M. Morris ◽  
E.F. Erickson ◽  
S. Colgan ◽  
J. Simpson
Keyword(s):  
Fine Structure ◽  
Radio Emission ◽  
Galactic Center ◽  
Galactic Plane ◽  
Line Emission ◽  
Far Infrared ◽  
Thin Filaments ◽  
Ob Stars ◽  
Structure Line ◽  
Photoionization Model

The remarkable filament system seen in radio observations in the vicinity of the galactic center includes two thin filaments which arch away from the galactic plane (E.G. Yusef-Zadem et al 1984). The brightest part of each of these thermal structures is located at GO.10+0.02 and GO.07+0.04. Morris and Yusef-Zadem (1989) reason that photoionization by OB stars is unlikely on geometrical and morphological grounds. They suggest a magnetohydrodynamic mechanism to account for the radio emission and ionization. Erickson et al. (1968) were able to explain most of their observations of the far infrared (FIR) fine structure line emission from these locations in terms of a photoionization model.

scholarly journals Statistical Properties of Highly Luminous HII Regions in the Interacting Zone of the Antennae Galaxies, and Comparison with the Molecular Cloud Component

2012 ◽  
Vol 8 (S292) ◽  
pp. 156-156
Author(s):  
Joan Font ◽  
John E. Beckman ◽  
Javier Zaragoza ◽  
Santi Erroz-Ferrer ◽  
Begoña Garcia-Lorenzo
Keyword(s):  
Line Emission ◽  
Hii Regions ◽  
Molecular Data ◽  
Data Cube ◽  
Ionized Gas ◽  
La Palma ◽  
Fabry Perot ◽  
Different Populations ◽  
The Masses ◽  
Two Populations

AbstractWe have used the package CLOUDPROPS (Rosolowsky & Leroy 2008) in order to identify clouds, which are contained in data cubes of molecular/Hα line emission, and extract their properties. The molecular data cube is taken from the ALMA public archive and the ionized hydrogen data cube was obtained with the Fabry-Perot interferometer, GHαFaS, on the 4.2 m WHT in La Palma. In our study of the overlap region of the Antennae galaxies we have identified two populations of molecular clouds, above and below log M/M⊙ = 6.75 (in agreement with Wei et al. 2012 who find the break in mass at log M/M⊙ = 6.5) and two different populations of ionized gas clouds; the break in the luminosity occurs near log L = 37.6 (see Fig. 1). We have measured the masses, velocity dispersions and luminosities of the clouds, and derived relation between them for each population. Population II clouds (both molecular and ionized) tend to be located in the most luminous regions, while population I clouds can be found in the outskirts. This work will be published in Font et al. (2013).

scholarly journals HI and continuum structure of external galaxies compared to the situation in the galaxy

1979 ◽  
Vol 84 ◽  
pp. 417-426
Author(s):  
Arnold H. Rots
Keyword(s):  
Gas Flow ◽  
Density Wave ◽  
Wave Theory ◽  
Radio Halo ◽  
Ngc 6946 ◽  
Total Luminosity ◽  
The Galaxy ◽  
External Galaxies ◽  
Continuum Structure ◽  
Density Wave Theory

Continuum observations of NGC 6946 strongly suggest the presence of an exponential non-thermal disk component. When applied to galactic 408 MHz observations, the scale length is found to be between 5 and 6 kpc. Continuing the parallel with NGC 6946, a total luminosity of 2 × 1010L⊙is derived. Observations of the edge-on galaxies NGC 891 and 4631 show the existence of flattened halos with a steep spectrum around these galaxies. This is consistent with the constraints that are known for the galactic radio halo. On the basis of the radial distribution of HI in the Galaxy and in M81 three regimes can be defined: a central one which is hyperdeficient in hydrogen; a middle one which is deficient in HI, but not necessarily in total hydrogen; and an outer one which is neither deficient in HI, nor in H. Density wave theory, combined with gas flow dynamics appear a powerful tool in interpreting the kinematical data. No rotation curve is yet known to become Keplerian in the outer parts. Many external galaxies are warped, like our own; one of them, NGC 5907, does not have a visible companion.

scholarly journals Diffuse Ionized Gas in Halos of Spiral Galaxies

1997 ◽  
Vol 166 ◽  
pp. 525-538
Author(s):  
Ralf-Jürgen Dettmar
Keyword(s):  
Large Scale ◽  
Spiral Galaxies ◽  
Optical Emission ◽  
Radio Continuum ◽  
Formation Processes ◽  
Ionized Gas ◽  
Ob Stars ◽  
Diffuse Ionized Gas ◽  
Model Predictions ◽  
External Galaxies

AbstractOver the last couple of years Diffuse Ionized Gas (DIG) has been identified as an important constituent of the interstellar medium (ISM) in the halos of spiral galaxies. Imaging in and spectroscopy of optical emission lines allow us to study the distribution and excitation of this gas with a spatial resolution not achievable for other phases of the ISM in external galaxies. Its origin and ionization is under debate and give important constraints for models of the ISM in general and on the large scale exchange of matter between disk and halo in particular. This review summarizes more recent observational results and compares them with model predictions. The data available now demonstrate that the presence of DIG in the disk-halo interface of spiral galaxies is related to star formation processes in the underlying disk. While photoionization by OB stars in the disk seems a viable source for the power required to ionize the DIG, additional processes are needed to explain some of the spectral features. The observed correlation with properties of the non-thermal radio continuum indicate that magnetic fields and cosmic rays could play a role for the physics of this medium.

scholarly journals Infrared Observations of the Galactic Nucleus

1980 ◽  
Vol 5 ◽  
pp. 163-169 ◽  
Author(s):  
J. H. Lacy
Keyword(s):  
Stellar Population ◽  
Near Infrared ◽  
Line Emission ◽  
Far Infrared ◽  
Infrared Emission ◽  
Ionized Gas ◽  
Infrared Observations ◽  
Cool Stars ◽  
Infrared Sources ◽  
Near Infrared Emission

AbstractInfrared observations of the galactic nucleus and conclusions regarding the nature of the objects present there are reviewed. Observations of three sources of infrared radiation are discussed: near-infrared emission from cool stars, mid- and far-infrared emission from dust, and line emission from ionized gas. These observations provide information about the mass distribution, the stellar population, and the origin and ionization of the compact mid-infrared sources. The possibility of the existence of a massive central black hole is discussed.

The MPE/UCB far-infrared imaging Fabry-Perot interferometer (FIFI)

1991 ◽  
Vol 12 (8) ◽  
pp. 859-884 ◽  
Author(s):  
A. Poglitsch ◽  
J. W. Beeman ◽  
N. Geis ◽  
R. Genzel ◽  
M. Haggerty ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Far Infrared ◽  
Fabry Perot

scholarly journals Flavonoids improve drought tolerance of maize seedlings by regulating the homeostasis of reactive oxygen species

2021 ◽  
Author(s):  
Baozhu Li ◽  
Ruonan Fan ◽  
Guiling Sun ◽  
Ting Sun ◽  
Yanting Fan ◽  
...  
Keyword(s):  
Free Radicals ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Infrared Imaging ◽  
Oxygen Free Radicals ◽  
Transcriptome Profiling ◽  
Far Infrared ◽  
Drought Treatment ◽  
Physiological Characterization ◽  
Oxidative Damages

Abstract Background and aims As drought threatens the yield and quality of maize (Zea mays L.), it is important to dissect the molecular basis of maize drought tolerance. Flavonoids, participate in the scavenging of oxygen free radicals and alleviate stress-induced oxidative damages. This study aims to dissect the function of flavonoids in the improvement of maize drought tolerance. Methods Using far-infrared imaging screening, we previously isolated a drought overly insensitivity (doi) mutant from an ethyl methanesulfonate (EMS)-mutagenized maize library and designated it as doi57. In this study, we performed a physiological characterization and transcriptome profiling of doi57 in comparison to corresponding wild-type B73 under drought stress. Results Under drought stress, doi57 seedlings displayed lower leaf-surface temperature (LST), faster water loss, and better performance in growth than B73. Transcriptome analysis reveals that key genes involved in flavonoid biosynthesis are enriched among differentially expressed genes in doi57. In line with these results, more flavonols and less hydrogen peroxide (H2O2) were accumulated in guard cells of doi57 than in those of B73 with the decrease of soil water content (SWC). Moreover, the capacity determined from doi57 seedling extracts to scavenge oxygen free radicals was more effective than that of B73 under the drought treatment. Additionally, doi57 seedlings had higher photosynthetic rates, stomatal conductance, transpiration rates, and water use efficiency than B73 exposed to drought stress, resulting in high biomass and greater root/shoot ratios in doi57 mutant plants. Conclusion Flavonoids may facilitate maize seedling drought tolerance by lowering drought-induced oxidative damage as well regulating stomatal movement.

scholarly journals Bringing high spatial resolution to the far-infrared

2021 ◽  
Author(s):  
Hendrik Linz ◽  
Henrik Beuther ◽  
Maryvonne Gerin ◽  
Javier R. Goicoechea ◽  
Frank Helmich ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Formation Process ◽  
Far Infrared ◽  
Main Theme ◽  
Spatially Resolved ◽  
Research Areas ◽  
External Galaxies ◽  
Emergence Of Life ◽  
Fine Structure Lines

AbstractThe far-infrared (FIR) regime is one of the wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist. None of the medium-term satellite projects like SPICA, Millimetron, or the Origins Space Telescope will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO), light hydrides, and especially from water lines would open the door for transformative science. A main theme will be to trace the role of water in proto-planetary discs, to observationally advance our understanding of the planet formation process and, intimately related to that, the pathways to habitable planets and the emergence of life. Furthermore, key observations will zoom into the physics and chemistry of the star-formation process in our own Galaxy, as well as in external galaxies. The FIR provides unique tools to investigate in particular the energetics of heating, cooling, and shocks. The velocity-resolved data in these tracers will reveal the detailed dynamics engrained in these processes in a spatially resolved fashion, and will deliver the perfect synergy with ground-based molecular line data for the colder dense gas.

Optimized design of far-infrared Fabry-Perot resonators fabricated from YBa/sub 2/Cu/sub 3/O/sub 7/

1993 ◽  
Vol 3 (1) ◽  
pp. 2852-2855 ◽  
Author(s):  
C.G. Malone ◽  
Z.M. Zhang ◽  
M.I. Flik ◽  
E.G. Cravalho
Keyword(s):  
Far Infrared ◽  
Optimized Design ◽  
Fabry Perot
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