- ID:
- ivo://CDS.VizieR/J/AN/333/60
- Title:
- Colour indices of selected OB stars
- Short Name:
- J/AN/333/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have applied the method of investigating extinction curves using statistically meaningful samples that was proposed by us 25 years ago. The extensive data sets of the ANS (Astronomical Netherlands Satellite) and 2MASS (Two Micron All Sky Survey) were used, together with UBV photometry to create average extinction curves for samples of OB stars. Our results demonstrate that in the vast majority of cases the extinction curves are very close to the mean galactic extinction curve. Only a few objects were found to be obviously discrepant from the average. The latter phenomenon may be related to nitrogen chemistry in translucent interstellar clouds.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/582
- Title:
- Coma clusters and filaments galaxies FIR survey
- Short Name:
- J/MNRAS/458/582
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe a far-infrared survey of the Coma cluster and the galaxy filament it resides within. Our survey covers an area of ~150 deg^2^ observed by Herschel H-ATLAS (Herschel Astrophysical Terahertz Large Area Survey) in five bands at 100, 160, 250, 350 and 500{mu}m. The SDSS spectroscopic survey (m_r_<=17.8) is used to define an area (within the virial radius) and redshift selected (4268<v<9700km/s) sample of 744 Coma cluster galaxies - the Coma Cluster Catalogue. For comparison, we also define a sample of 951 galaxies in the connecting filament - the Coma Filament Catalogue. The optical positions and parameters are used to define appropriate apertures to measure each galaxy's far-infrared emission. We have detected 99 of 744 (13 per cent) and 422 of 951 (44 per cent) of the cluster and filament galaxies in the SPIRE 250um band. We consider the relative detection rates of galaxies of different morphological types finding that it is only the S0/Sa population that shows clear differences between the cluster and filament. We find no differences between the dust masses and temperatures of cluster and filament galaxies with the exception of early-type galaxy dust temperatures, which are significantly hotter in the cluster than in the filament (X-ray heating?). From a chemical evolution model, we find no evidence for different evolutionary processes (gas loss or infall) between galaxies in the cluster and filament.
- ID:
- ivo://CDS.VizieR/J/A+AS/141/113
- Title:
- Coma extensive H photometry
- Short Name:
- J/A+AS/141/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present extensive and accurate photometry in the near-infrared H band (about 1.62{mu}m) of a complete sample of objects in an area of about 400arcmin^2^ toward the Coma cluster of galaxies. The sample, including about 300 objects, is complete down to H~17mag, the exact value depending on the type of magnitude (isophotal, aperture, Kron) and the particular region studied. This is six magnitudes below the characteristic magnitude of galaxies, well into the dwarfs' regime at the distance of the Coma cluster. For each object (star or galaxy) we provide aperture magnitudes computed within five different apertures, the magnitude within the 22mag/arcsec^2^ isophote, the Kron magnitude and radius, magnitude errors, as well as the coordinates, the isophotal area, and a stellarity index. Photometric errors are 0.2mag at the completness limit. This sample is meant to be the zero-redshift reference for evolutionary studies of galaxies.
- ID:
- ivo://CDS.VizieR/J/AJ/136/2483
- Title:
- Comoving group associated with HD 141569
- Short Name:
- J/AJ/136/2483
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for a young stellar moving group associated with the star HD 141569 - a nearby, isolated Herbig AeBe primary member of a 5+/-3Myr-old triple star system on the outskirts of the Sco-Cen complex. Our spectroscopic survey identified a population of 21 Li-rich, >~30Myr-old stars within 30{deg} of HD 141569 which possess similar proper motions with the star. The spatial distribution of these Li-rich stars, however, is not suggestive of a moving group associated with the HD 141569 triplet, but rather this sample appears cospatial with Upper Scorpius (US) and Upper Centaurus Lupus (UCL). We apply a modified moving cluster parallax method to compare the kinematics of these youthful stars with those of the US and UCL. Eight new potential members of US and five new potential members of UCL are identified. A substantial moving group with an identifiable nucleus within 15{deg} (~30pc) of HD 141569 is not found in this sample. Evidently, the HD 141569 system formed ~5Myr ago in relative isolation, tens of parsecs away from the recent sites of star formation in the Ophiucus-Scorpius-Centaurus region.
- ID:
- ivo://CDS.VizieR/J/MNRAS/441/224
- Title:
- Compact FIR-bright sources in M33
- Short Name:
- J/MNRAS/441/224
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of a sample of far-infrared (FIR) sources detected on the Herschel broad-band maps of the nearby galaxy M33. We perform source photometry on the FIR maps as well as mid-infrared (MIR), H{alpha}, far-ultraviolet and integrated Hi and CO line emission maps. By fitting MIR/FIR dust emission spectra, the source dust masses, temperatures and luminosities are inferred. The sources are classified based on their H{alpha} morphology (sub-structured versus not-substructured) and on whether they have a significant CO detection (S/N>3{sigma}). We find that the sources have dust masses in the range 10^2^-10^4^M_{sun}_ and that they present significant differences in their inferred dust/star formation/gas parameters depending on their H{alpha} morphology and CO detection classification. The results suggests differences in the evolutionary states or in the number of embedded HII regions between the sub-samples. The source background-subtracted dust emission seems to be predominantly powered by local star formation, as indicated by a strong correlation between the dust luminosity and the dust-corrected H{alpha} luminosity and the fact that the extrapolated young stellar luminosity is high enough to account for the observed dust emission. Finally, we do not find a strong correlation between the dust-corrected H{alpha} luminosity and the dust mass of the sources, consistent with previous results on the breakdown of simple scaling relations at sub-kpc scales. However, the scatter in the relation is significantly reduced by correcting the H{alpha} luminosity for the age of the young stellar populations in the star-forming regions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1527
- Title:
- Compact HII regions IR photometry
- Short Name:
- J/MNRAS/391/1527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 3.6, 4.5, 5.8 and 8.0um photometry and mapping for 58 compact HII regions identified using the Spitzer Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE). These are used to investigate trends in the colours, magnitudes and structures of the sources, together with spatial variations in flux ratio. It is concluded that most of the sources are remarkably similar, and have comparable variations in flux ratio as a function of position within the shells, together with very narrowly defined ranges of colour index.
- ID:
- ivo://CDS.VizieR/J/A+A/610/A27
- Title:
- Compact radio sources in NGC 6334D to F
- Short Name:
- J/A+A/610/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The presence and properties of compact radio sources embedded in massive star forming regions can reveal important physical properties about these regions and the processes occurring within them. The NGC 6334 complex, a massive star forming region, has been studied extensively. Nevertheless, none of these studies has focused in its content in compact radio sources. Aims. Our goal here is to report on a systematic census of the compact radio sources toward NGC 6334, and their characteristics. This will be used to attempt to define their very nature. We used the VLA C band (4-8GHz) archive data with 0.36" (500AU) of spatial resolution and noise level of 50Jy/bm to carry out a systematic search for compact radio sources within NGC 6334. We also searched for infrared counterparts to provide some constraints on the nature of the detected radio sources. A total of 83 compact sources and three slightly resolved sources were detected. Most of them are here reported for the first time. We found that 29 of these 86 sources have infrared counterparts and three are highly variable. Region D contains 18 of these sources. The compact source toward the center, in projection, of region E is also detected. From statistical analyses, we suggest that the 83 reported compact sources are real and most of them are related to NGC 6334 itself. A stellar nature for 27 of them is confirmed by their IR emission. Compared with Orion, region D suffers a deficit of compact radio sources. The infrared nebulosities around two of the slightly resolved sources are suggested to be warm dust, and we argue that the associated radio sources trace free-free emission from ionized material. We confirm the thermal radio emission of the compact source in region E. However, its detection at infrared wavelengths implies that it is located in the foreground of the molecular cloud. Finally, three strongly variable sources are suggested to be magnetically active young stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/757/141
- Title:
- Companion IR detection limits in young associations
- Short Name:
- J/ApJ/757/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The frequency and properties of multiple star systems offer powerful tests of star formation models. Multiplicity surveys over the past decade have shown that binary properties vary strongly with mass, but the functional forms and the interplay between frequency and semimajor axis remain largely unconstrained. We present the results of a large-scale survey of multiplicity at the bottom of the initial mass function in several nearby young associations, encompassing 78 very low mass members observed with Keck laser guide star adaptive optics. Our survey confirms the overall trend observed in the field for lower-mass binary systems to be less frequent and more compact, including a null detection for any substellar binary systems with separations wider than ~7AU. Combined with a Bayesian re-analysis of existing surveys, our results demonstrate that the binary frequency and binary separations decline smoothly between masses of 0.5M_{sun}_ and 0.02M_{sun}_, though we cannot distinguish the functional form of this decline due to a degeneracy between the total binary frequency and the mean binary separation. We also show that the mass ratio distribution becomes progressively more concentrated at q~1 for declining masses, though a small number of systems appear to have unusually wide separations and low-mass ratios for their mass. Finally, we compare our results to synthetic binary populations generated by smoothed particle hydrodynamic simulations, noting the similarities and discussing possible explanations for the differences.
- ID:
- ivo://CDS.VizieR/J/ApJ/807/23
- Title:
- Companions of RS CVn primaries. I. sig Gem
- Short Name:
- J/ApJ/807/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To measure the properties of both components of the RS Canum Venaticorum binary {sigma} Geminorum ({sigma} Gem), we directly detect the faint companion, measure the orbit, obtain model-independent masses and evolutionary histories, detect ellipsoidal variations of the primary caused by the gravity of the companion, and measure gravity darkening. We detect the companion with interferometric observations obtained with the Michigan InfraRed Combiner at Georgia State University's Center for High Angular Resolution Astronomy Array with a primary-to-secondary H-band flux ratio of 270+/-70. A radial velocity curve of the companion was obtained with spectra from the Tillinghast Reflector Echelle Spectrograph on the 1.5m Tillinghast Reflector at Fred Lawrence Whipple Observatory. We additionally use new observations from the Tennessee State University Automated Spectroscopic and Photometric Telescopes (AST and APT, respectively). From our orbit, we determine model-independent masses of the components (M1=1.28+/-0.07M_{sun}_, M2=0.73+/-0.03M_{sun}_), and estimate a system age of 5+/-1Gyr. An average of the 27 year APT light curve of {sigma} Gem folded over the orbital period (P=19.6027+/-0.0005days) reveals a quasi-sinusoidal signature, which has previously been attributed to active longitudes 180{deg} apart on the surface of {sigma} Gem. With the component masses, diameters, and orbit, we find that the predicted light curve for ellipsoidal variations due to the primary star partially filling its Roche lobe potential matches well with the observed average light curve, offering a compelling alternative explanation to the active longitudes hypothesis. Measuring gravity darkening from the light curve gives {beta}<0.1, a value slightly lower than that expected from recent theory.
- ID:
- ivo://CDS.VizieR/J/AJ/151/85
- Title:
- Companions to APOGEE stars. I.
- Short Name:
- J/AJ/151/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In its three years of operation, the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed >14000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical radial velocity precision of ~100-200 m/s, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Here we present initial results from a catalog of 382 of the most compelling stellar and substellar companion candidates detected by APOGEE, which orbit a variety of host stars in diverse Galactic environments. Of these, 376 have no previously known small separation companion. The distribution of companion candidates in this catalog shows evidence for an extremely truncated brown dwarf (BD) desert with a paucity of BD companions only for systems with a<0.1-0.2 AU, with no indication of a desert at larger orbital separation. We propose a few potential explanations of this result, some which invoke this catalog's many small separation companion candidates found orbiting evolved stars. Furthermore, 16 BD and planet candidates have been identified around metal-poor ([Fe/H]<-0.5) stars in this catalog, which may challenge the core accretion model for companions >10 M_Jup_. Finally, we find all types of companions are ubiquitous throughout the Galactic disk with candidate planetary-mass and BD companions to distances of ~6 and ~16 kpc, respectively.
