- ID:
- ivo://CDS.VizieR/J/ApJS/95/457
- Title:
- IRAS images of nearby dark clouds
- Short Name:
- J/ApJS/95/457
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated ~100 nearby molecular clouds using the extensive, all-sky database of IRAS. The clouds in this study cover a wide range of physical properties including visual extinction, size, mass, degree of isolation, homogeneity and morphology. IRAS 100 and 60 micrometre co-added images were used to calculate the 100 micrometre optical depth of dust in the clouds. These images of dust optical depth compare very well with ^12^CO and ^13^CO observations, and can be related to H_2_ column density. From the optical depth images we locate the edges of dark clouds and the dense cores inside them. We have identified a total of 43 "IRAS clouds" (regions with Av>2) which contain a total of 255 "IRAS cores" (regions with Av>4) and we catalog their physical properties. We find that the clouds are remarkably filamentary, and that the cores within the clouds are often distributed along the filaments. The largest cores are usually connected to other large cores by filaments. We have developed selection criteria to search the IRAS Point Source Catalog for stars that are likely to be associated with the clouds and we catalog the IRAS sources in each cloud or core. Optically visible stars associated with the clouds have been identified from the Herbig and Bell catalog. From these data we characterize the physical properties of the clouds including their star-formation efficiency.
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Search Results
- ID:
- ivo://CDS.VizieR/VII/185
- Title:
- IRAS 1.2 Jy IRAS Redshift Survey
- Short Name:
- VII/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is an explanation of the redshift survey of Fisher, Huchra, Strauss, Davis, Yahil and Schlegel; the data set is described in full in ApJ 361, 49 (1990). The data for the brighter half are included in ApJ Supp 1992, 83, 29; the data for the fainter half are included in a paper submitted for publication to the Astrophysical Journal Supplement. The survey contains 9897 objects selected from the IRAS database according to the criteria listed in that paper, briefly: F60 > 1.2 Jy; F60^2^ > F12 f25; |b| > 5; high source density flag at 60 microns not raised. Thus, the file consists of both galaxies and Galaxian contaminants; this is explained below. The sample contains ~5320 galaxies, and 14 objects without id's at the present time.
- ID:
- ivo://CDS.VizieR/J/ApJS/143/277
- Title:
- IRAS 1Jy sample of ultraluminous galaxies. I.
- Short Name:
- J/ApJS/143/277
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An imaging survey of the IRAS 1Jy sample of 118 ultraluminous infrared galaxies was conducted at optical (R) and near-infrared (K') wavelengths using the University of Hawaii 2.2 m telescope. The methods of observation and data reduction are described. An R and K' atlas of the entire sample is presented along with some of the basic astrometric and photometric parameters derived from these images. A more detailed analysis of these data is presented in a companion paper (Veilleux et al., 2002, Cat. <J/ApJS/143/315>).
- ID:
- ivo://CDS.VizieR/J/ApJS/143/315
- Title:
- IRAS 1Jy sample of ultraluminous galaxies. II.
- Short Name:
- J/ApJS/143/315
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An R and K' atlas of the IRAS 1 Jy sample of 118 ultraluminous infrared galaxies (ULIGs) was presented in a companion paper (our Paper I, Kim et al., 2002, Cat. <J/ApJS/143/277>). The present paper discusses the results from the analysis of these images supplemented with new spectroscopic data obtained at Keck.
- ID:
- ivo://CDS.VizieR/III/197
- Title:
- IRAS Low Resolution Spectra
- Short Name:
- III/197
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IRAS survey instrumentation included a low-resolution spectrometer which covered the wavelength range between 8 and 22 um. The spectrometer operated during the entire survey, providing spectra of the brighter point sources. For details about the spectrometer, the reader is referred to the published book, chapter IX. The spectra included in file "lrs.dat" contain 200 points each, 100 points in the 8-13um range, and 100 points in the 11-22um range. There is therefore an overlapping between the longer wavelengths of the first sample and the shorter wavelengths of the second sample. The data points are stored as scaled integer arrays in the file "lrs.dat"; the corresponding values of the wavelengths are available in the file "calib.dat" . The file "lrs.dat" includes also data taken from the IRAS point source catalog <II/125>.
- ID:
- ivo://CDS.VizieR/J/A+A/468/1001
- Title:
- IRAS 20178+4046 maps at 610 and 1280MHz
- Short Name:
- J/A+A/468/1001
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of the ultra compact HII region associated with IRAS 20178+4046. This enables us to probe the different components associated with this massive star forming region.
- ID:
- ivo://CDS.VizieR/J/A+A/499/233
- Title:
- IRAS 05345+3157 mm high-angular resolution maps
- Short Name:
- J/A+A/499/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To better understand the initial conditions of the high-mass star formation process, it is crucial to study at high-angular resolution the morphology, the kinematics, and eventually the interactions of the coldest condensations associated with intermediate-/high-mass star forming regions. The paper studies the cold condensations in the intermediate-/high-mass proto-cluster IRAS 05345+3157, focusing the attention on the interaction with the other objects in the cluster. We have performed millimeter high-angular resolution observations, both in the continuum and several molecular lines, with the PdBI and the SMA. The millimeter maps reveal the presence of 3 cores inside the interferometers primary beam, called C1-a, C1-b and C2. The lines, specifically N2H+ and N2D+, indicate the presence of two potential pre-stellar condensations (called N and S) not associated with the continuum sources. C1-b is very likely associated with a newly formed early-B ZAMS star embedded inside a hot-core, while C1-a is more likely associated with a class 0 intermediate-mass protostar. The nature of C2 is unclear. Both C1-a and C1-b are good candidates as driving sources of a powerful CO outflow, strongly interacting with both N and S, as demonstrated by the velocity gradient across both condensations. Our major conclusion is that the chemical properties of these pre-stellar cores are similar to those observed in low-mass isolated ones, while the kinematics is dominated by the turbulence triggered by the CO outflow, which can influence their evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/594/A115
- Title:
- IRAS08589-4714 molecular gas
- Short Name:
- J/A+A/594/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the region IRAS 08589-4714 with the aim of characterizing the molecular environment. We observed the ^12^CO(3-2), ^13^CO(3-2), C^18^O(3-2), HCO^+^(3-2), and HCN(3-2) molecular lines in a region of 150"x150", centered on the IRAS source, to analyze the distribution and characteristics of the molecular gas linked to the IRAS source.
- ID:
- ivo://CDS.VizieR/J/ApJ/397/520
- Title:
- IRAS observations in Cr A
- Short Name:
- J/ApJ/397/520
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of IRAS data for a 57pc^2^ area of the nearby Corona Australis dark cloud complex. A total of 79 far-infrared sources are detected at 12{mu}m or in at least three IRAS bands. Combining these data with both newly obtained and previously published optical/infrared data, a total of 16 IRAS sources are identified with young stellar objects which are in close proximity to the R Coronae Australis cloud or Rossano Cloud B. Among these objects is a cold, heavily obscured young stellar object, IRAS 32, which radiates only in the 25-100{mu}m bands and is found to be associated with an extended near-infrared nebula. The majority of the remaining 63 IRAS sources in our sample appear to be related to field stars. A total of 24 young stellar objects are now known to be associated with the Cr A cloud and we investigate their collective properties through analysis of their spectral energy distributions. As observed for embedded populations in other dark clouds, the shapes of the spectral energy distributions constitute a nearly continuous sequence from cold, heavily obscured objects (extreme Class I) to T Tauri stars (Class II), with about equal numbers of Class I and Class II sources. There is a hint of a segregation of the shapes of the spectral energy distributions with source luminosity: eight of nine sources with L>1.8L_{sun}_ display Class I or flat energy distributions. We conclude that star formation in the Cr A cloud has proceeded in a manner similar to that in the rho Ophiuchi cloud in terms of duration and efficiency. We attribute the relatively low number of young stellar objects in Cr A to its lower mass of both low-density and high-density molecular gas. The luminosity function of the Cr A sources is unique only by the presence of six intermediate-luminosity (~100L_{sun}_) objects. Either the cloud has formed intermediate-mass stars more efficiently than lower mass objects relative to other dark clouds or several of these objects are interlopers.
- ID:
- ivo://CDS.VizieR/J/other/NewA/9.509
- Title:
- IRAS observations of Be stars
- Short Name:
- J/other/NewA/9.5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The IRAS associations for 193 Be stars are identified in this paper. From the infrared colors, the IRAS low-resolution spectra (LRS) and the spectral types, some physical properties and environment of the samples are discussed. It can be concluded that not only free-free emission or free-bound emission from the circumstellar ionized gas can be responsible for the large IR excesses of Be stars as suggested previously, but also, for some Be stars, thermal radiation from the circumstellar dust and/or nebula around the star can produce large IR excess as well. It is also found that the far IR excess of Be stars increases.
