New far infrared observations of the central 30ʹ of the galaxy

1982 ◽  
Author(s):  
W. A. Dent ◽  
M. W. Werner ◽  
I. Gatley ◽  
E. E. Becklin ◽  
R. H. Hildebrand ◽  
...  
Keyword(s):  
Far Infrared ◽  
Infrared Observations ◽  
The Galaxy

Far-Infrared Observations of the Center of the Galaxy

1994 ◽  
pp. 239-248
Author(s):  
A. Poglitsch ◽  
N. Geis ◽  
R. Genzel ◽  
F. Herrmann ◽  
J. M. Jackson ◽  
...  
Keyword(s):  
Far Infrared ◽  
Infrared Observations ◽  
The Galaxy

scholarly journals Infrared observations of circumstellar ejecta around Luminous Blue Variables

1989 ◽  
Vol 113 ◽  
pp. 165-176
Author(s):  
Peter J. McGregor
Keyword(s):  
Radial Distance ◽  
Far Infrared ◽  
Circumstellar Disks ◽  
Infrared Emission ◽  
Ring Structure ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Luminous Blue Variables ◽  
The Galaxy ◽  
Favorable Conditions

AbstractRecent infrared spectroscopy and imaging of LBVs lead to the following results. CO overtone emission at 2.3μm has been found in 13 LBVs in the Galaxy and the LMC. This emission is collisionally excited in warm (3000 – 5000 K), dense (NH> 1010cm-3) circumstellar material. Circumstellar disks offer favorable conditions for the formation and excitation of CO molecules and are very likely the location of the observed emission. It is proposed that the LBVs showing 2.3 μm CO overtone emission possess the highest density circumstellar disks.A group of eight LBVs has been identified in the LMC with He I 2.058 μm emission stronger than H I Brγ. This group includes the CO emission star HD 37836. Helium is over-abundant in these stars withN(He)/N(H) ranging from 0.2 to >0.5. Remarkably five of the helium strong stars belong to the small class of Ofpe/WN9 stars and a further two are probably related to this class.Slit scans of the galactic LBV AG Car have resolved the far-infrared emission from this star, clearly showing it to originate from cool dust in the circumstellar ring structure. Thermal equilibrium considerations require large grains in the ring in order to match the measured grain temperature and radial distance. Similar slit scans of the galactic B[e] star HD 87643 fail to resolve the far-infrared emission from this star at the 10″ level.

scholarly journals Accretion and Outflow Activity in the Earliest Phases of Star-Formation: CO, Sub-mm Continuum, and Near-Infrared Observations

1997 ◽  
Vol 163 ◽  
pp. 725-726
Author(s):  
K.-W. Hodapp ◽  
E. F. Ladd
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Point Sources ◽  
Spectral Energy ◽  
Infrared Observations ◽  
Circumstellar Material ◽  
Dense Cores ◽  
Wavelength Radiation ◽  
Main Component

Stars in the earliest phases of their formation, i.e., those accreting the main component of their final mass, are deeply embedded within dense cores of dust and molecular material. Because of the high line-of-sight extinction and the large amount of circumstellar material, stellar emission is reprocessed by dust into long wavelength radiation, typically in the far-infrared and sub-millimeter bands. Consequently, the youngest sources are strong submillimeter continuum sources, and often undetectable as point sources in the near-infrared and optical. The most deeply embedded of these sources have been labelled “Class 0” sources by André, Ward-Thompson, & Barsony (1994), in an extension of the spectral energy distribution classification scheme first proposed by Adams, Lada, & Shu (1987).

scholarly journals Megamasers as probes of galaxy mass spectrum evolution

1991 ◽  
Vol 147 ◽  
pp. 440-440
Author(s):  
V.K. Khersonskii ◽  
N.V. Voshchinnikov
Keyword(s):  
Mass Spectrum ◽  
Spectral Line ◽  
Emission Line ◽  
Frequency Shift ◽  
Empirical Relation ◽  
Far Infrared ◽  
Merging Galaxies ◽  
Maser Emission ◽  
The Galaxy ◽  
Very High

OH megamasers having very high luminosities in the spectral line can be effectively used for the probing of the evolutionary properties of the galaxies in the earliest cosmological epochs. The frequency shift of the emission line uniqually determines the redshift z, which tells about the epoch of emission. One of the important cosmological problems is the investigation of the galaxy mass spectrum in the expanding Universe. There is the empirical relation between the OH and far-infrared luminosities of galaxies. Therefore, if in the earliest cosmological epochs, there were galaxies with sufficient powerful infrared excesses and containing molecular material, they can be detected using the observations of their OH maser emission. The interacting and merging galaxies can be considered as the best candidates for such objects.

scholarly journals Hidden molecular outflow in the LIRG Zw 049.057

2018 ◽  
Vol 609 ◽  
pp. A75 ◽  
Author(s):  
N. Falstad ◽  
S. Aalto ◽  
J. G. Mangum ◽  
F. Costagliola ◽  
J. S. Gallagher ◽  
...  
Keyword(s):  
Far Infrared ◽  
Minor Axis ◽  
Spectral Lines ◽  
Continuum Emission ◽  
High Angular Resolution ◽  
Molecular Gas ◽  
Nuclear Activity ◽  
Molecular Outflow ◽  
The Galaxy ◽  
Excitation Conditions

Context. Feedback in the form of mass outflows driven by star formation or active galactic nuclei is a key component of galaxy evolution. The luminous infrared galaxy Zw 049.057 harbours a compact obscured nucleus with a possible far-infrared signature of outflowing molecular gas. Due to the high optical depths at far-infrared wavelengths, however, the interpretation of the outflow signature is uncertain. At millimeter and radio wavelengths, the radiation is better able to penetrate the large columns of gas and dust responsible for the obscuration. Aims. We aim to investigate the molecular gas distribution and kinematics in the nucleus of Zw 049.057 in order to confirm and locate the molecular outflow, with the ultimate goal to understand how the nuclear activity affects the host galaxy. Methods. We used high angular resolution observations from the Submillimeter Array (SMA), the Atacama Large Millimeter/submillimeter Array (ALMA), and the Karl G. Jansky Very Large Array (VLA) to image the CO J = 2–1 and J = 6–5 emission, the 690 GHz continuum, the radio centimeter continuum, and absorptions by rotationally excited OH. Results. The CO line profiles exhibit wings extending ~ 300 km s-1 beyond the systemic velocity. At centimeter wavelengths, we find a compact (~ 40 pc) continuum component in the nucleus, with weaker emission extending several 100 pc approximately along the major and minor axes of the galaxy. In the OH absorption lines toward the compact continuum, wings extending to a similar velocity as for the CO are only seen on the blue side of the profile. The weak centimeter continuum emission along the minor axis is aligned with a highly collimated, jet-like dust feature previously seen in near-infrared images of the galaxy. Comparison of the apparent optical depths in the OH lines indicate that the excitation conditions in Zw 049.057 differ from those within other OH megamaser galaxies. Conclusions. We interpret the wings in the spectral lines as signatures of a nuclear molecular outflow. A relation between this outflow and the minor axis radio feature is possible, although further studies are required to investigate this possible association and understand the connection between the outflow and the nuclear activity. Finally, we suggest that the differing OH excitation conditions are further evidence that Zw 049.057 is in a transition phase between megamaser and kilomaser activity.

scholarly journals A test of the ability of current bulk optical models to represent the radiative properties of cirrus cloud across the mid-and far-infrared

2020 ◽  
Author(s):  
Richard J. Bantges ◽  
Helen E. Brindley ◽  
Jonathan E. Murray ◽  
Alan E. Last ◽  
Cathryn Fox ◽  
...  
Keyword(s):  
Compensation Effect ◽  
Far Infrared ◽  
Single Scattering ◽  
Radiative Properties ◽  
Cirrus Cloud ◽  
Atmospheric Measurements ◽  
Infrared Observations ◽  
Ice Cloud ◽  
Infrared Frequency Range ◽  
The Uk

Abstract. Measurements of mid- to far-infrared nadir radiances obtained from the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft during the Cirrus Coupled Cloud-Radiation Experiment (CIRCCREX) are used to assess the performance of various ice cloud bulk optical (single-scattering) property models. Through use of a minimisation approach, we find that the simulations can reproduce the observed spectra in the mid-infrared to within measurement uncertainty but are unable to simultaneously match the observations over the far-infrared frequency range. When both mid and far-infrared observations are used to minimise residuals, first order estimates of the flux differences between the best performing simulations and observations indicate a strong compensation effect between the mid and far infrared such that the absolute broadband difference is

scholarly journals Big Three Dragons: A [N ii] 122 μm Constraint and New Dust-continuum Detection of a z = 7.15 Bright Lyman-break Galaxy with ALMA

2021 ◽  
Vol 923 (1) ◽  
pp. 5
Author(s):  
Yuma Sugahara ◽  
Akio K. Inoue ◽  
Takuya Hashimoto ◽  
Satoshi Yamanaka ◽  
Seiji Fujimoto ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Abundance Ratio ◽  
Continuum Emission ◽  
Spectral Energy ◽  
High Ionization ◽  
The Galaxy ◽  
Infrared Spectral ◽  
Best Fit ◽  
Redshift Galaxies

Abstract We present new Atacama Large Millimeter/submillimeter Array Band 7 observational results of a Lyman-break galaxy at z = 7.15, B14-65666 (“Big Three Dragons”), which is an object detected in [O iii] 88 μm, [C ii] 158 μm, and dust continuum emission during the epoch of reionization. Our targets are the [N ii] 122 μm fine-structure emission line and the underlying 120 μm dust continuum. The dust continuum is detected with a ∼19σ significance. From far-infrared spectral energy distribution sampled at 90, 120, and 160 μm, we obtain a best-fit dust temperature of 40 K (79 K) and an infrared luminosity of log 10 ( L IR / L ⊙ ) = 11.6 (12.1) at the emissivity index β = 2.0 (1.0). The [N ii] 122 μm line is not detected. The 3σ upper limit of the [N ii] luminosity is 8.1 × 107 L ⊙. From the [N ii], [O iii], and [C ii] line luminosities, we use the Cloudy photoionization code to estimate nebular parameters as functions of metallicity. If the metallicity of the galaxy is high (Z > 0.4 Z ⊙), the ionization parameter and hydrogen density are log 10 U ≃ − 2.7 ± 0.1 and n H ≃ 50–250 cm−3, respectively, which are comparable to those measured in low-redshift galaxies. The nitrogen-to-oxygen abundance ratio, N/O, is constrained to be subsolar. At Z < 0.4 Z ⊙, the allowed U drastically increases as the assumed metallicity decreases. For high ionization parameters, the N/O constraint becomes weak. Finally, our Cloudy models predict the location of B14-65666 on the BPT diagram, thereby allowing a comparison with low-redshift galaxies.

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