- ID:
- ivo://CDS.VizieR/J/ApJ/707/103
- Title:
- Observation of Ser FIRS 1 at 230GHz
- Short Name:
- J/ApJ/707/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results of a program to characterize the disk and envelope structure of typical Class 0 protostars in nearby low-mass star-forming regions. We use Spitzer Infrared Spectrograph (IRS) mid-infrared spectra, high-resolution Combined Array for Research in Millimeter-wave Astronomy (CARMA) 230GHz continuum imaging, and two-dimensional radiative transfer models to constrain the envelope structure, as well as the size and mass of the circumprotostellar disk in Serpens FIRS 1. The primary envelope parameters (centrifugal radius, outer radius, outflow opening angle, and inclination) are well constrained by the spectral energy distribution (SED), including Spitzer IRAC and MIPS photometry, IRS spectra, and 1.1mm Bolocam photometry. These together with the excellent uv-coverage (4.5-500k{lambda}) of multiple antenna configurations with CARMA allow for a robust separation of the envelope and a resolved disk. The SED of Serpens FIRS 1 is best fit by an envelope with the density profile of a rotating, collapsing spheroid with an inner (centrifugal) radius of approximately 600AU, and the millimeter data by a large resolved disk with M_disk_~1.0M_{sun}_ and R_disk_~300AU.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/669/446
- Title:
- Observations of SiO masers
- Short Name:
- J/ApJ/669/446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of SiO millimeter line observations of a sample of known SiO maser sources covering a wide dust temperature range. A cold part of the sample was selected from the SiO maser sources found in our recent SiO maser survey of cold dusty objects. The aim of the present research is to investigate the causes of the correlation between infrared colors and SiO maser intensity ratios among different transition lines. In particular, the correlation between infrared colors and SiO maser intensity ratio among the J=1-0 v=1, 2, and 3 lines are our main concern in this paper. We observed in total 75 SiO maser sources with the Nobeyama 45m telescope quasi-simultaneously in the SiO J=1-0 v=0, 1, 2, 3, 4 and J=2-1 v=1, 2 lines. We also observed the sample in the ^29^SiO J=1-0 v=0 and J=2-1 v=0 lines, ^30^SiO J=1-0 v=0 line, and the H_2_O 61,6-52,3 line.
- ID:
- ivo://CDS.VizieR/J/AcA/43/209
- Title:
- OB stars extinction based in IR photometry
- Short Name:
- J/AcA/43/209
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents an extensive survey of interstellar extinction curves derived from the near IR photometric measurements of early type stars belonging to our Galaxy. This survey is more extensive and deeper than any other one, based on spectral data. The IR magnitudes of about 500 O and B type stars with E(B-V)>=0.05 were selected from literature. The IR color excesses are determined with the aid of "artificial standards". The results indicate that the extinction law changes from place to place. The mean galactic extinction curve in the near IR is very similar in different directions and changes very little from the value R=3.10+/-0.05 obtained in this paper.
804. OCSVM anomalies
- ID:
- ivo://CDS.VizieR/J/A+A/606/A39
- Title:
- OCSVM anomalies
- Short Name:
- J/A+A/606/A39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wide-angle photometric surveys of previously uncharted sky areas or wavelength regimes will always bring in unexpected sources - novelties or even anomalies - whose existence and properties cannot be easily predicted from earlier observations. Such objects can be efficiently located with novelty detection algorithms. Here we present an application of such a method, called one-class support vector machines (OCSVM), to search for anomalous patterns among sources preselected from the mid-infrared AllWISE catalogue covering the whole sky. To create a model of expected data we train the algorithm on a set of objects with spectroscopic identifications from the SDSS DR13 database, present also in AllWISE. The OCSVM method detects as anomalous those sources whose patterns - WISE photometric measurements in this case - are inconsistent with the model. Among the detected anomalies we find artefacts, such as objects with spurious photometry due to blending, but more importantly also real sources of genuine astrophysical interest. Among the latter, OCSVM has identified a sample of heavily reddened AGN/quasar candidates distributed uniformly over the sky and in a large part absent from other WISE-based AGN catalogues. It also allowed us to find a specific group of sources of mixed types, mostly stars and compact galaxies. By combining the semi-supervised OCSVM algorithm with standard classification methods it will be possible to improve the latter by accounting for sources which are not present in the training sample, but are otherwise well-represented in the target set. Anomaly detection adds flexibility to automated source separation procedures and helps verify the reliability and representativeness of the training samples. It should be thus considered as an essential step in supervised classification schemes to ensure completeness and purity of produced catalogues.
- ID:
- ivo://CDS.VizieR/J/A+A/327/755
- Title:
- OH maser emission from IRAS sources
- Short Name:
- J/A+A/327/755
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A high-sensitivity search for water maser emission at 22.2 GHz has been performed on a sample of 91 IRAS point sources at high-latitudes. The aim of the survey is to verify if these clouds are capable of star formation as indicated by the presence of water masers. The sample is based on the recent work of Magnani et al. (1995ApJS...96..159M) who have identified 192 infrared objects from the IRAS Faint Source Survey possibly associated with translucent clouds at galactic latitudes |b|>=30{deg}. These IRAS sources have far-infrared colours typical of young stellar objects and pre-main-sequence stars and thus provide a starting list for further studies about their actual nature. H_2_O maser emission is a good diagnostic of the presence of dense gas and of recent star formation. We did not find water maser emission at a level of 0.2-0.5Jy (3{sigma}) in any of the 91 objects. The negative result indicates that these high-latitude sources do not represent potential sites of star formation, consistent with the fact that most high-latitude molecular clouds do not appear gravitationally bound.
- ID:
- ivo://CDS.VizieR/J/ApJS/155/595
- Title:
- OH maser IRAS and MSX observations
- Short Name:
- J/ApJS/155/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present OH maser observations at 1612, 1665, 1667, and 1720MHz for 86 likely post-asymptotic giant branch (post-AGB) stars selected from a survey of 1612MHz maser sources in the Galactic plane. The observations were taken with the Parkes Telescope and the Australia Telescope Compact Array between 2002 September and 2003 August. We redetected all 86 sources at 1612MHz, while 27 sources were detected at 1665MHz and 45 at 1667MHz. One source was redetected at 1720MHz. We present a classification scheme for the maser profiles and show that 25% of sources in our sample are likely to have asymmetric or bipolar outflows.
- ID:
- ivo://CDS.VizieR/J/AJ/124/100
- Title:
- OH megamasers at z>0.1. III
- Short Name:
- J/AJ/124/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the final results from the Arecibo Observatory OH megamaser survey. We discuss in detail the properties of the remaining 18 OH megamasers detected in the survey, including three redetections. We place upper limits on the OH emission from 85 nondetections and examine the properties of 25 ambiguous cases for which the presence or absence of OH emission could not be determined. The complete survey has discovered 50 new OH megamasers (OHMs) in (ultra)luminous infrared galaxies ([U]LIRGs), which doubles the sample of known OHMs and increases the sample at z>0.1 sevenfold.
- ID:
- ivo://CDS.VizieR/J/AJ/133/496
- Title:
- OH megamasers infrared photometry
- Short Name:
- J/AJ/133/496
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- OH megamasers are the most luminous masers in the universe. The total of 109 OH megamaser (OHM) galaxies known so far have been collected, and cross-identifications of those OHM galaxies with Two Micron All Sky Survey (2MASS) sources are made in this paper. Using 2MASS (Cat. II/246) and IRAS (Cat. II/125, II/156) data, the infrared properties of OHM-detected and non-detected sources are compared.
- ID:
- ivo://CDS.VizieR/J/ApJS/109/489
- Title:
- OH observations of Arecibo OH/IR stars
- Short Name:
- J/ApJS/109/489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Arecibo 1612MHz survey of a complete sample of color-selected IRAS sources with 25{mu}m fluxes S(25)>2 Jy detected 393 OH/IR stars. A complementary 1667 and 1665MHz OH survey of these objects is presented here. Main-line masers have been detected in 238 surveyed objects: 18 exhibit only 1665MHz emission, 220 exhibit 1667MHz masers, and 119 exhibit both. The main lines were not detected in 159 objects.
- ID:
- ivo://CDS.VizieR/J/AJ/123/2772
- Title:
- OH-selected AGB and post-AGB objects. I.
- Short Name:
- J/AJ/123/2772
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using 766 compact objects found in a systematic survey of the Galactic plane in the 1612MHz masing OH line, new light is cast on the IR properties of evolved stars on the thermally pulsing asymptotic giant branch (AGB) and beyond. The usual mid-IR selection criteria for post-AGB, based on IRAS colors, largely fail to distinguish early post-AGB stages. A two-color diagram from much narrower band MSX flux densities, with bimodal distributions, provides a better tool for doing this. Four mutually consistent selection criteria for OH-masing red protoplanetary nebulae are given, as well as two for early post-AGB masers and one for all post-AGB masers including the earliest ones. All these criteria miss a group of blue, high-outflow post-AGB sources with 60{mu}m excess; these will be discussed in detail in Paper II (Sevenster, 2002AJ....123.2772S). The majority of post-AGB sources show regular double-peaked spectra in the OH 1612MHz line, with fairly low outflow velocities, although the fractions of single peaks and irregular spectra may vary with age and mass. The OH flux density shows a fairly regular relation with the stellar flux and the envelope optical depth, with the maser efficiency increasing with IRAS color R_21_. The OH flux density is linearly correlated with the 60{mu}m flux density.
