- ID:
- ivo://CDS.VizieR/J/A+A/549/A8
- Title:
- Atmospheric extinction properties above Mauna Kea
- Short Name:
- J/A+A/549/A8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new atmospheric extinction curve for Mauna Kea spanning 3200-9700{AA}. It is the most comprehensive to date, being based on some 4285 standard star spectra obtained on 478 nights spread over a period of 7 years obtained by the Nearby SuperNova Factory using the SuperNova Integral Field Spectrograph. This mean curve and its dispersion can be used as an aid in calibrating spectroscopic or imaging data from Mauna Kea, and in estimating the calibration uncertainty associated with the use of a mean extinction curve. Our method for decomposing the extinction curve into physical components, and the ability to determine the chromatic portion of the extinction even on cloudy nights, is described and verified over the wide range of conditions sampled by our large dataset. We demonstrate good agreement with atmospheric science data obtain at nearby Mauna Loa Observatory, and with previously published measurements of the extinction above Mauna Kea.
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- ID:
- ivo://CDS.VizieR/J/AJ/152/180
- Title:
- Bolometric fluxes of eclipsing binaries in Tycho-2
- Short Name:
- J/AJ/152/180
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present fits to the broadband photometric spectral energy distributions (SEDs) of 158 eclipsing binaries (EBs) in the Tycho-2 catalog. These EBs were selected because they have highly precise stellar radii, effective temperatures, and in many cases metallicities previously determined in the literature, and thus have bolometric luminosities that are typically good to <~10%. In most cases the available broadband photometry spans a wavelength range 0.4-10{mu}m, and in many cases spans 0.15-22{mu}m. The resulting SED fits, which have only extinction as a free parameter, provide a virtually model-independent measure of the bolometric flux at Earth. The SED fits are satisfactory for 156 of the EBs, for which we achieve typical precisions in the bolometric flux of {\simeq}3%. Combined with the accurately known bolometric luminosity, the result for each EB is a predicted parallax that is typically precise to <~5%. These predicted parallaxes-with typical uncertainties of 200{mu}as-are 4-5 times more precise than those determined by Hipparcos for 99 of the EBs in our sample, with which we find excellent agreement. There is no evidence among this sample for significant systematics in the Hipparcos parallaxes of the sort that notoriously afflicted the Pleiades measurement. The EBs are distributed over the entire sky, span more than 10mag in brightness, reach distances of more than 5kpc, and in many cases our predicted parallaxes should also be more precise than those expected from the Gaia first data release. The EBs studied here can thus serve as empirical, independent benchmarks for these upcoming fundamental parallax measurements.
- ID:
- ivo://CDS.VizieR/J/A+A/458/113
- Title:
- BVRIc photometry towards inner Galactic Bulge
- Short Name:
- J/A+A/458/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained BVRI photometry for 21 stellar fields located in directions towards the central 3.5{deg} of the Galaxy. Each field is 10x10 arcmin in size, and a total of ~2x10^5^ stars were measured.
- ID:
- ivo://CDS.VizieR/J/ApJS/227/18
- Title:
- Candidate stellar bowshock nebulae from MIR
- Short Name:
- J/ApJS/227/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We identify 709 arc-shaped mid-infrared nebula in 24um Spitzer Space Telescope or 22um Wide Field Infrared Explorer surveys of the Galactic Plane as probable dusty interstellar bowshocks powered by early-type stars. About 20% are visible at 8um or at shorter mid-infrared wavelengths. The vast majority (660) have no previous identification in the literature. These extended infrared sources are strongly concentrated near the Galactic mid-plane, with an angular scale height of ~0.6{deg}. All host a symmetrically placed star implicated as the source of a stellar wind sweeping up interstellar material. These are candidate "runaway" stars potentially having high velocities in the reference frame of the local medium. Among the 286 objects with measured proper motions, we find an unambiguous excess with velocity vectors aligned with the infrared morphology-kinematic evidence that many of these are "runaway" stars with large peculiar motions responsible for the bowshock signature. We discuss a population of "in situ" bowshocks (~103 objects) that face giant HII regions where the relative motions between the star and ISM may be caused by bulk outflows from an overpressured bubble. We also identify ~58 objects that face 8um bright-rimmed clouds and apparently constitute a sub-class of in situ bowshocks where the stellar wind interacts with a photoevaporative flow (PEF) from an eroding molecular cloud interface (i.e., "PEF bowshocks"). Orientations of the acurate nebulae exhibit a correlation over small angular scales, indicating that external influences such as HII regions are responsible for producing some bowshock nebulae. However, the vast majority of the nebulae in this sample appear to be isolated (499 objects) from obvious external influence
- ID:
- ivo://CDS.VizieR/J/ApJS/194/6
- Title:
- Candidate X-ray emitting OB stars in Carina
- Short Name:
- J/ApJS/194/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a new survey of massive, OB stars throughout the Carina Nebula using the X-ray point source catalog provided by the Chandra Carina Complex Project (CCCP) in conjunction with infrared (IR) photometry from the Two Micron All-Sky Survey and the Spitzer Space Telescope Vela-Carina survey. Mid-IR photometry is relatively unaffected by extinction, hence it provides strong constraints on the luminosities of OB stars, assuming that their association with the Carina Nebula, and hence their distance, is confirmed. We fit model stellar atmospheres to the optical (UBV) and IR spectral energy distributions (SEDs) of 182 OB stars with known spectral types and measure the bolometric luminosity and extinction for each star. Using X-ray emission as a strong indicator of association with Carina, we identify 94 candidate OB stars with L_bol_>~10^4^L_{sun}_ by fitting their IR SEDs. If the candidate OB stars are eventually confirmed by follow-up spectroscopic observations, the number of cataloged OB stars in the Carina Nebula will increase by ~50%.
- ID:
- ivo://CDS.VizieR/J/ApJ/838/61
- Title:
- Candidate X-ray OB stars in MYStIX regions
- Short Name:
- J/ApJ/838/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive O-type and early B-type (OB) stars in the nearby Galaxy remain incompletely cataloged due to high extinction, bright visible and infrared nebular emission in H II regions, and high field star contamination. These difficulties are alleviated by restricting the search to stars with X-ray emission. Using the X-ray point sources from the Massive Young Star-forming Complex Study in Infrared and X-Rays (MYStIX) survey of OB-dominated regions, we identify 98 MYStIX candidate OB (MOBc) stars by fitting their 1-8{mu}m spectral energy distributions (SEDs) with reddened stellar atmosphere models. We identify 27 additional MOBc stars based on JHK_S_ photometry of X-ray stars lacking SED fitting. These candidate OB stars indicate that the current census of stars earlier than B1, taken across the 18 MYStIX regions studied, is less than 50% complete. We also fit the SEDs of 239 previously published OB stars to measure interstellar extinction and bolometric luminosities, revealing six candidate massive binary systems and five candidate O-type (super)giants. As expected, candidate OB stars have systematically higher extinction than previously published OB stars. Notable results for individual regions include identification of the OB population of a recently discovered massive cluster in NGC 6357, an older OB association in the M17 complex, and new massive luminous O stars near the Trifid Nebula. In several relatively poorly studied regions (RCW 38, NGC 6334, NGC 6357, Trifid, and NGC 3576), the OB populations may increase by factors of 2.
- ID:
- ivo://CDS.VizieR/J/A+A/515/A42
- Title:
- Catalog of high extinction clouds
- Short Name:
- J/A+A/515/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The earliest phases of massive star formation are found in cold and dense infrared dark clouds (IRDCs). Since the detection method of IRDCs is very sensitive to the local properties of the background emission, we present here an alternative method to search for high column density in the Galactic plane by using infrared extinction maps. We find clouds between 1 and 5kpc, of which many were missed by previous surveys. By studying the physical conditions of a subsample of these clouds, we aim at a better understanding of the initial conditions of massive star formation. We made extinction maps of the Galactic plane based on the 3.6-4.5 microns color excess between the two shortest wavelength Spitzer IRAC bands, reaching to visual extinctions of ~100mag and column densities of 9x10^22^cm^-2^. From this we compiled a new sample of cold and compact high extinction clouds. We used the MAMBO array at the IRAM 30m telescope to study the morphology, masses, and densities of the clouds and the dense clumps within them. The latter were followed up by pointed ammonia observations with the 100m Effelsberg telescope to determine rotational temperatures and kinematic distances. Extinction maps of the Galactic plane trace large scale structures such as the spiral arms. The extinction method probes lower column densities, N(H_2)~4x10^22^cm^-2^, than the 1.2mm continuum, which reaches up to N(H_2)~3x10^23^cm^-2^ but is less sensitive to large scale structures. The 1.2mm emission maps reveal that the high extinction clouds contain extended cold dust emission, from filamentary structures to still diffuse clouds. Most of the clouds are dark in 24 microns, but several show already signs of star formation via maser emission or bright infrared sources, suggesting that the high extinction clouds contain a variety of evolutionary stages. The observations suggest an evolutionary scheme from dark, cold and diffuse clouds, to clouds with a stronger 1.2mm peak and to finally clouds with many strong 1.2mm peaks, which are also warmer, more turbulent, and already have some star formation signposts.
- ID:
- ivo://CDS.VizieR/J/A+A/600/A50
- Title:
- Catalog of hot subdwarf stars
- Short Name:
- J/A+A/600/A50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In preparation for the upcoming all-sky data releases of the Gaia mission we compiled a catalog of known hot subdwarf stars and candidates drawn from the literature and yet unpublished databases. By matching this catalog with astrometric and photometric data from the Gaia mission, we will develop selection criteria to construct a homogeneous, magnitude-limited all-sky catalog of hot subdwarf stars based on Gaia data.
- ID:
- ivo://CDS.VizieR/II/62
- Title:
- Catalogue of Extinction Data
- Short Name:
- II/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Extinction values and distances have been computed from UBV, MK and beta data for more than 11000 O to F stars, including 7565 O and B stars. For 1020 stars two independent distance moduli were derived using MK and beta absolute magnitudes. The mean values of their differences is less than 0.01mag.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A193
- Title:
- Catalogue of hot subdwarf stars DR2
- Short Name:
- J/A+A/635/A193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In light of substantial new discoveries of hot subdwarfs by ongoing spectroscopic surveys and the availability of new all-sky data from ground-based photometric surveys and the Gaia mission Data Release 2, we compiled an updated catalogue of the known hot subdwarf stars.
