- ID:
- ivo://CDS.VizieR/J/ApJ/784/111
- Title:
- Morphology of candidate intermediate-mass SFRs
- Short Name:
- J/ApJ/784/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an all-sky sample of 984 candidate intermediate-mass Galactic star-forming regions that are color selected from the Infrared Astronomical Satellite (IRAS) Point Source Catalog and morphologically classify each object using mid-infrared Wide-field Infrared Survey Explorer (WISE) images. Of the 984 candidates, 616 are probable star-forming regions (62.6%), 128 are filamentary structures (13.0%), 39 are point-like objects of unknown nature (4.0%), and 201 are galaxies (20.4%). We conduct a study of four of these regions, IRAS 00259+5625, IRAS 00420+5530, IRAS 01080+5717, and IRAS 05380+2020, at Galactic latitudes|b|>5{deg} using optical spectroscopy from the Wyoming Infrared Observatory, along with near-infrared photometry from the Two-Micron All Sky Survey, to investigate their stellar content. New optical spectra, color-magnitude diagrams, and color-color diagrams reveal their extinctions, spectrophotometric distances, and the presence of small stellar clusters containing 20-78M_{sun}_ of stars. These low-mass diffuse star clusters contain ~65-250 stars for a typical initial mass function, including one or more mid-B stars as their most massive constituents. Using infrared spectral energy distributions we identify young stellar objects near each region and assign probable masses and evolutionary stages to the protostars. The total infrared luminosity lies in the range 190-960L_{sun}_, consistent with the sum of the luminosities of the individually identified young stellar objects.
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- ID:
- ivo://CDS.VizieR/J/ApJ/698/1682
- Title:
- Most luminous dusty galaxies
- Short Name:
- J/ApJ/698/1682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A summary of mid-infrared continuum luminosities arising from dust is given for very luminous galaxies, L_IR_>10^12^L_{sun}_, with 0.005<z<3.2 containing active galactic nuclei (AGNs), including 115 obscured AGNs and 60 unobscured (type 1) AGNs. All sources have been observed with the Spitzer Infrared Spectrograph. Obscured AGNs are defined as having optical depth {tau}>0.7 in the 9.7um silicate absorption feature (i.e., half of the continuum is absorbed) and having equivalent width of the 6.2um polycyclic aromatic hydrocarbon feature <0.1um (to avoid sources with a significant starburst component). Unobscured AGNs are defined as those that show silicate in emission. Luminosity {nu}L_{nu}_(8um) for the most luminous obscured AGNs is found to scale as (1+z)^2.6^ to z=2.8. For unobscured AGNs, the scaling with redshift is similar, but luminosities {nu}L_{nu}_(8um) are approximately three times greater for the most luminous sources. Using both obscured and unobscured AGNs having total infrared fluxes from the Infrared Astronomical Satellite, empirical relations are found between {nu}L_{nu}_(8um) and L_IR_.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1221
- Title:
- Most luminous LMC sources at 8{mu}m
- Short Name:
- J/AJ/136/1221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To ascertain the nature of the brightest compact mid-infrared (mid-IR) sources in the Large Magellanic Cloud (LMC), we have applied an updated version of Buchanan et al.'s (2006AJ....132.1890B) Two Micron All Sky Survey (2MASS)-Midcourse Space Experiment (MSX) color classification system, which is based on the results of Spitzer Space Telescope spectroscopy, to a mid-IR (8um) flux-limited sample of 250 LMC objects for which 2MASS and MSX photometry is available. The resulting 2MASS-MSX ("JHK8") color-based classifications of these sources, which constitute the most mid-IR-luminous objects in the LMC, were augmented, cross-checked, and corrected where necessary via a variety of independent means, such that only 46 sources retain tentative classifications and only 10 sources cannot be classified at all. The sample is found to consist primarily of carbon-rich asymptotic giant branch (AGB) stars (35%), red supergiants (RSGs) (18%), and compact HII regions (32%), with additional, small populations of oxygen-rich AGB stars (~5%), dusty, early-type emission-line stars (~3%), and foreground, O-rich AGB stars in the Milky Way (~3%).
- ID:
- ivo://CDS.VizieR/J/ApJ/886/40
- Title:
- Most luminous SPIRITS IR transients follow-up obs.
- Short Name:
- J/ApJ/886/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic study of the most luminous (MIR [Vega magnitudes] brighter than -14) infrared (IR) transients discovered by the SPitzer InfraRed Intensive Transients Survey (SPIRITS) between 2014 and 2018 in nearby galaxies (D<35Mpc). The sample consists of nine events that span peak IR luminosities of M_[4.5],peak_ between -14 and -18.2, show IR colors between 0.2<([3.6]-[4.5])<3.0, and fade on timescales between 55d<t_fade_<480d. The two reddest events (A_V_>12) show multiple, luminous IR outbursts over several years and have directly detected, massive progenitors in archival imaging. With analyses of extensive, multiwavelength follow-up, we suggest the following possible classifications: five obscured core-collapse supernovae (CCSNe), two erupting massive stars, one luminous red nova, and one intermediate-luminosity red transient. We define a control sample of all optically discovered transients recovered in SPIRITS galaxies and satisfying the same selection criteria. The control sample consists of eight CCSNe and one Type Iax SN. We find that 7 of the 13 CCSNe in the SPIRITS sample have lower bounds on their extinction of 2<A_V_<8. We estimate a nominal fraction of CCSNe in nearby galaxies that are missed by optical surveys as high as 38.5_-21.9_^+26.0^% (90% confidence). This study suggests that a significant fraction of CCSNe may be heavily obscured by dust and therefore undercounted in the census of nearby CCSNe from optical searches.
- ID:
- ivo://CDS.VizieR/J/other/Ap/44.335
- Title:
- M stars in Cepheus region
- Short Name:
- J/other/Ap/44.33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a spectral classification of 257 M stars observed in the Cepheus region are given. Their equatorial coordinates, photographic stellar magnitudes, and spectral subtypes were determined. These stars are giants and supergiants, in all probability. None of them appear in a catalog of variable stars. It is assumed that variability might be detected in many of them upon further study. Fifty-two of the stars have been identified with infrared sources. In addition to the originally published data, magnitudes, positions, cross-identifications and notes have been added in May 2002. (see the "History" section below)
- ID:
- ivo://CDS.VizieR/V/114
- Title:
- MSX6C Infrared Point Source Catalog
- Short Name:
- V/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Version 2.3 of the Midcourse Space Experiment (MSX) Point Source Catalog (PSC), which supersedes the version (1.2) that was released in 1999 (Cat. V/107), contains over 100,000 more sources than the previous version. The photometry is based on co-added image plates, as opposed to single-scan data, which results in improved sensitivity and hence reliability in the fluxes. Comparison with Tycho-2 positions indicates that the astrometric accuracy of the new catalog is more than 1'' better than that in Version 1.2. In addition to the Galactic plane, Areas Missed by the Infrared Astronomical Satellite (IRAS), and the Large Magellanic Cloud, which were included in the previous catalog, Version 2.3 includes data from the Small Magellanic Cloud, eight nearby galaxies, and several molecular clouds and star forming regions. The infrared instrument on MSX was named SPIRIT III; it was a 35cm clear aperture off-axis telescope with five line scanned infrared focal plane arrays of 18.3arcsec square pixels, with a high sensitivity (0.1Jy at 8.3micron). The 6 bands are B1 (4.29micron, FWHM 4.22-4.36micron), B2 (4.25micron, 4.24-4.45micron), A (8.28micron, 6.8-10.8micron), C (12.13micron, 11.1-13.2micron), D (14.65micron, 13.5-15.9micron), and E (21.34micron, 18.2-25.1micron). The MSX catalog names of the sources have been defined according to International Astronomical Union (IAU) conventions with a unique identifier combined with the position of the source. In this case, the MSX PSC V2.3 sources are named using the convention MSX6C GLLL.llll+/-BB.bbbb, where MSX6C denotes that this is MSX data run using Version 6.0 of the CONVERT software, and GLLL.llll+/-BB.bbbb gives the Galactic coordinates of the source. (Names in the minicatalogs may differ slightly from those given in Kraemer et al. 2002AJ....124.2990K, 2003AJ....126.1423K) For ease of handling, the main catalog is broken into six files: five for the Galactic plane survey, plus the primary high latitude regions (the IRAS gaps and the LMC). The supplementary catalogs are the singleton catalog, the low-reliability catalog, and minicatalogs for 19 selected regions. All catalogs have the same format. However, the minicatalogs for the galaxies (except the SMC) and Orion do not have all the fields filled in because they were solely created from the images, not from the Point Source Extractor; there are no singleton files for these regions. Also, the minicatalogs may not have singleton or low-reliability counterparts if no sources met the inclusion criteria. All told, there are a total of 45 data files.
- ID:
- ivo://CDS.VizieR/V/107
- Title:
- MSX5C Infrared Point Source Catalog
- Short Name:
- V/107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The principal objective of the astronomy experiments abroad the Midcourse Space Experiment (MSX) was to complete the census of the mid-infrared (4.2-25{mu}m) sky: the areas missed by the IRAS mission (about 4% of the sky was not surveyed by IRAS), and the Galactic Plane where the sensitivity of IRAS was degraded by confusion noise in the regions of high source densities or structured extended emission. The infrared instrument on MSX is named SPIRIT III; it is a 35cm clear aperture off-axis telescope with five line scanned infrared focal plane arrays of 18.3arcsec square pixels, with a high sensitivity (0.1Jy at 8.3{mu}m). The characteristics of the 6 bands B1, B2, A, C, D and E are summarized in the "Note (1)" below. The data are contained in 7 files according to the location on the sky: 5 are related to the Galactic Plane, one (non-plane) contains the IRAS gap catalog, the the lmc.dat file contains the observations of the Large Magellanic Cloud.
- ID:
- ivo://CDS.VizieR/V/98
- Title:
- MSX Infrared Astrometric Catalog
- Short Name:
- V/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The MSX Infrared Astrometric Catalog has been contructed as a tool for improving the pointing accuracy of infrared observations. The catalog contains 177,860 astrometric stars, 61,242 which have been identified with their infrared counterparts from IRAS catalogs and the Catalog of Infrared Observations through position and color matching. Infrared flux densities are predicted for 6 wavelength bands between 4 and 22um. The catalog identifications are complete to within the spatial coverage of current surveys for those astrometric stars brightest in the infrared. By predicting fluxes of astrometric stars without IR identifications we are able to extend the catalog to areas of the sky which were incomplete in the IRAS catalogs. Furthermore, by retaining stars below the brightness limit of current surveys we are able to provide better spatial coverage to help point or position the next generation of infrared telescopes.
- ID:
- ivo://CDS.VizieR/J/ApJ/639/227
- Title:
- MSX IRDC candidate catalog
- Short Name:
- J/ApJ/639/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use 8.3{mu}m mid-infrared images acquired with the Midcourse Space Experiment satellite to identify and catalog infrared dark clouds (IRDCs) in the first and fourth quadrants of the Galactic plane. Because IRDCs are seen as dark extinction features against the diffuse Galactic infrared background, we identify them by first determining a model background from the 8.3{mu}m images and then searching for regions of high decremental contrast with respect to this background. IRDC candidates in our catalog are defined by contiguous regions bounded by closed contours of a 2{sigma} decremental contrast threshold. We identify 10,931 candidate IRDCs. For each IRDC, we also catalog cores. These cores, defined as localized regions with at least 40% higher extinction than the cloud's average extinction, are found by iteratively fitting two-dimensional elliptical Gaussian functions to the contrast peaks. We identify 12,774 cores. The catalog contains the position, angular size, orientation, area, peak contrast, peak contrast signal-to-noise, and integrated contrast of the candidate IRDCs and their cores.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1423
- Title:
- MSX 8.3um fluxes of star-forming regions
- Short Name:
- J/AJ/126/1423
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have imaged seven nearby star-forming regions, the Rosette Nebula, the Orion Nebula, W3, the Pleiades, G300.2-16.8, S263, and G159.6-18.5, with the Spatial Infrared Imaging Telescope on the Midcourse Space Experiment (MSX) satellite at 18" resolution at 8.3, 12.1, 14.7, and 21.3{mu}m. The large angular scale of the regions imaged (~7.2-50deg^2^) makes these data unique in terms of the combination of size and resolution. In addition to the star-forming regions, two cirrus-free fields (MSXBG 160 and MSXBG 161) and a field near the south Galactic pole (MSXBG 239) were also imaged. Point sources have been extracted from each region, resulting in the identification over 500 new sources (i.e., no identified counterparts at other wavelengths), as well as over 1300 with prior identifications. The extended emission from the star-forming regions is described, and prominent structures are identified, particularly in W3 and Orion. The Rosette Nebula is discussed in detail. The bulk of the mid-infrared emission is consistent with that of photon-dominated regions, including the elephant trunk complex. The central clump, however, and a line of site toward the northern edge of the cavity show significantly redder colors than the rest of the Rosette complex.
