- ID:
- ivo://CDS.VizieR/J/A+A/619/A124
- Title:
- THOR survey in northern Galactic plane
- Short Name:
- J/A+A/619/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio continuum surveys of the Galactic plane can find and characterize HII regions, supernova remnants (SNRs), planetary nebulae (PNe), and extragalactic sources. A number of surveys at high angular resolution (<~25") at different wavelengths exist to study the interstellar medium (ISM), but no comparable high-resolution and high-sensitivity survey exists at long radio wavelengths around 21cm. Our goal is to investigate the 21cm radio continuum emission in the northern Galactic plane at <25" resolution. We observed a large fraction of the Galactic plane in the first quadrant of the Milky Way (l=14.0{deg}-67.4{deg} and |b|<=1.25{deg}) with the Karl G. Jansky Very Large Array (VLA) in the C-configuration covering six continuum spectral windows. These data provide a detailed view on the compact as well as extended radio emission of our Galaxy and thousands of extragalactic background sources. We used the BLOBCAT software and extracted 10916 sources. After removing spurious source detections caused by the sidelobes of the synthesised beam, we classified 10387 sources as reliable detections.We smoothed the images to a common resolution of 25" and extracted the peak flux density of each source in each spectral window (SPW) to determine the spectral indices {alpha} (assuming I(nu){prop.to}nu^alpha^). By cross-matching with catalogs of HII regions, SNRs, PNe, and pulsars, we found radio counterparts for 840 HII regions, 52 SNRs, 164 PNe, and 38 pulsars. We found 79 continuum sources that are associated with X-ray sources. We identified 699 ultrasteep spectral sources (alpha<-1.3) that could be high-redshift galaxies. Around 9000 of the sources we extracted are not classified specifically, but based on their spatial and spectral distribution, a large fraction of them is likely to be extragalactic background sources. More than 7750 sources do not have counterparts in the SIMBAD database, and more than 3760 sources do not have counterparts in the NED database. Studying the long wavelengths cm continuum emission and the associated spectral indices allows us to characterize a large fraction of Galactic and extragalactic radio sources in the area of the northern inner Milky Way. This database will be extremely useful for future studies of a diverse set of astrophysical objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/580/A112
- Title:
- THOR. The HI, OH, Recombination Line Survey
- Short Name:
- J/A+A/580/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To study the atomic, molecular and ionized emission of Giant Molecular Clouds (GMCs), we have initiated a Large Program with the VLA: 'THOR - The HI, OH, Recombination Line survey of the Milky Way'. We map the 21cm HI line, 4 OH lines, 19 H{alpha} recombination lines and the continuum from 1 to 2GHz of a significant fraction of the Milky Way (l=15-67{deg}, |b|<1{deg}) at ~20" resolution. In this paper, we focus on the HI emission from the W43 star-formation complex. Classically, the HI 21cm line is treated as optically thin with column densities calculated under this assumption. This might give reasonable results for regions of low-mass star-formation, however, it is not sufficient to describe GMCs. We analyzed strong continuum sources to measure the optical depth, and thus correct the HI 21cm emission for optical depth effects and weak diffuse continuum emission. Hence, we are able to measure the HI mass of W43 more accurately and our analysis reveals a lower limit of M=6.6x10^6^M_{sun}_, which is a factor of 2.4 larger than the mass estimated with the assumption of optically thin emission. The HI column densities are as high as N(HI)~150M_{sun}_/pc^2^~1.9x10^22cm^-2^, which is an order of magnitude higher than for low mass star formation regions. This result challenges theoretical models that predict a threshold for the HI column density of ~10M_{sun}_/pc^2^, at which the formation of molecular hydrogen should set in. By assuming an elliptical layered structure for W43, we estimate the particle density profiles. While at the cloud edge atomic and molecular hydrogen are well mixed, the center of the cloud is strongly dominated by molecular hydrogen. We do not identify a sharp transition between hydrogen in atomic and molecular form. Our results are an important characterization of the atomic to molecular hydrogen transition in an extreme environment and challenges current theoretical models.
- ID:
- ivo://CDS.VizieR/J/AJ/158/185
- Title:
- Three binary systems in the Large Magellanic Cloud
- Short Name:
- J/AJ/158/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the physical properties and apsidal motion elements of three eccentric eclipsing binaries in the Large Magellanic Cloud. The time-series photometric observations were carried out for a total of 41 nights between 2018 November and 2019 February using the KMTNet 1.6 m telescopes installed in South Africa and Australia. The radial velocities of binary components were measured using about 15 spectra per system collected from the ESO Science Archive Facility, which were observed with the Very Large Telescope 8.2 m telescope. The effective temperatures of the more massive binary components were determined to be 19000+/-500 K for OGLE-LMC-ECL-05797, 17000+/-500 K for OGLE-LMC-ECL-05861, and 19000+/-500 K for OGLE-LMC-ECL-06510 by comparing the observed spectra and the stellar atmosphere models obtained from the BOSZ spectral library. The absolute dimensions of each system were derived by analyzing the radial velocity curves together with the light curves obtained from the KMTNet, OGLE, and MACHO observations during about three decades. For the apsidal motion study, new eclipse timings were derived from the KMTNet and survey photometry. The apsidal motion elements of the three binaries were determined from both light curve and eclipse timing analysis. The periods of apsidal motion were 67+/-2 yr for OGLE-LMC-ECL-05797, 124+/-6 yr for OGLE-LMC-ECL-05861, and 39+/-1 yr for OGLE-LMC-ECL-06510 and their internal structure constants (ISCs) were log k_2,obs_=-2.3+/-0.1, -2.4+/-0.1, and -2.1+/-0.1 in the same order. The observed ISCs of OGLE-LMC-ECL-05797 and OGLE-LMC-ECL-05861 showed a good match to the theoretical ISC values, while the value of OGLE- LMC-ECL-06510 was somewhat larger than the theoretical one.
- ID:
- ivo://CDS.VizieR/J/A+A/541/A121
- Title:
- Three conformers of n-butyl cyanide
- Short Name:
- J/A+A/541/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The saturated n-propyl cyanide has recently been detected in Sagittarius B2(N). The next larger unbranched alkyl cyanide is n-butyl cyanide. We want to provide accurate rest frequency predictions beyond the millimeter wave range to search for this molecule in the Galactic center source Sagittarius B2(N) and facilitate its detection in space. The laboratory rotational spectrum of n-butyl cyanide has been investigated between 75 and 348GHz. We have searched for emission lines caused by the molecule in our sensitive IRAM 30m molecular line survey of Sagittarius B2(N). More than one thousand rotational transitions have been identified in the laboratory for each of the three conformers for which limited data had been obtained previously in a molecular beam microwave study. The quantum number range has been greatly extended to J~120 or more and Ka>35, resulting in accurate spectroscopic parameters and accurate rest frequency calculations up to about 500GHz for strong to moderately weak transitions of the two lower energy conformers. Upper limits of the column densities of N<=3x10^15^cm^-2^ and 8x10^15^cm^-2^ were derived towards Sagittarius B2(N) for the two lower energy conformers, anti-anti and gauche-anti, respectively. The present data will be helpful to identify n-butyl cyanide at millimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection in Sagittarius B2(N) with ALMA seems feasible.
- ID:
- ivo://CDS.VizieR/J/MNRAS/483/5508
- Title:
- Three new Galactic star clusters
- Short Name:
- J/MNRAS/483/5508
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the serendipitous discovery of three new open clusters, named UFMG 1, UFMG 2 and UFMG 3 in the field of the intermediate-age cluster NGC 5999, by using Gaia DR2 data. A colour-magnitude filter tailored for a proper selection of main-sequence stars and red clump giants turned evident the presence of NGC 5999 and these three new stellar groups in proper motion space. Their structural parameters were derived from King-profile fittings over their projected stellar distributions and isochrone fits were performed on the clusters cleaned colour-magnitude diagrams built with Gaia bands to derive their astrophysical parameters. The clusters projected sky motion were calculated for each target using our members selection. Distances to the clusters were inferred from stellar parallaxes through a bayesian model, showing that they are marginally consistent with their isochronal distances , considering the random and systematic uncertainties involved. The new clusters are located in the nearby Sagittarius arm (d~1.5kpc) with NGC 5999 at the background (d~1.8kpc). They contain at least a few hundred stars of nearly solar metallicity and have ages between 100 and 1400Myr.
- ID:
- ivo://CDS.VizieR/J/ApJ/789/139
- Title:
- Three O-type binaries photometry in LMC
- Short Name:
- J/ApJ/789/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper in a series devoted to the study of massive binary systems in the Large Magellanic Cloud (LMC). We mainly aim to provide accurate data that constrains the mass-luminosity relation for the most massive stars but also to address the long lasting problem known as the "mass discrepancy." We present here our results for three binaries (LMC 169782, LMC 171520, and [P93] 921) harboring the earliest O-type components-ranging from O4 V to O6.5 V-among our sample of 17 systems. Our photometry provided accurate periods for the studied systems, allowing the spectroscopic observations to be performed at selected phases where the radial velocity separation between binary components is larger. Following the procedure outlined in our first paper of this series, after solving the radial velocity curves for orbital parameters, we used tomographic reconstruction to obtain the individual spectra of each star, from which we determined effective temperatures via a model atmosphere fitting with FASTWIND. This information, combined with the light-curve analysis that was performed with GENSYN, enabled the determination of absolute masses, radii, and bolometric luminosities that are compared with those predicted by modern stellar evolutionary models finding that they agree within the uncertainties. Nevertheless, the comparison seems to confirm the small differences found in the first paper of this series in the sense that the evolutionary masses are slightly larger than the Keplerian ones, with differences averaging ~10%, or alternatively, the stellar evolutionary models predict luminosities that are somewhat lower than observed. Still, the overall agreement between the current evolutionary models and the empirically determined stellar parameters is remarkable.
- ID:
- ivo://CDS.VizieR/J/AJ/154/260
- Title:
- Three short-period eclipsing binaries BVRI photometry
- Short Name:
- J/AJ/154/260
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present new BVRI light curves of short-period contact eclipsing binaries V1101 Her and AD Phe from our observations carried out from 2014 to 2015 using the SARA KP and SARA CT telescopes. There is an eclipsing binary located at {alpha}(2000)=01h16m36.15s and {delta}(2000)=-39{deg}49'55.7" in the field of view of AD Phe. We derived an updated ephemeris and found there a cyclic variation overlaying a continuous period increase (V1101 Her) and decrease (AD Phe). This kind of cyclic variation may be attributed to the light time effect via the presence of the third body or magnetic activity cycle. The orbital period increase suggests that V1101 Her is undergoing a mass-transfer from the primary to the secondary component (dM_1_/dt=2.64(+/-0.11)x10^-6^ M_{sun}_/yr) with the third body (P3=13.9(+/-1.9) years), or 2.81(+/-0.07)x10^-6^ M_{sun}_/yr for an increase and magnetic cycle (12.4(+/-0.5) years). The long-term period decrease suggests that AD Phe is undergoing a mass-transfer from the secondary component to the primary component at a rate of -8.04(+/-0.09)x10^-8^ M_{sun}_/yr for a period decrease and the third body (P3=56.2(+/-0.8) years), or -7.11(+/-0.04)x10^-8^ M_{sun}_/yr for a decrease and magnetic cycle (50.3(+/-0.5) years). We determined their orbital and geometrical parameters. For AD Phe, we simultaneously analyzed our BVRI light curves and the spectroscopic observations obtained by Duerbeck & Rucinski (2007AJ....133..169D). The spectral type of V1101 Her was classified as G0+/-2V by LAMOST stellar spectra survey. The asymmetry of the R-band light curve of AD Phe obtained by McFarlane & Hilditch in 1987 (1987MNRAS.227..381M) is explained by a cool spot on the primary component.
- ID:
- ivo://CDS.VizieR/J/MNRAS/422/1988
- Title:
- Three short-period, transiting exoplanets
- Short Name:
- J/MNRAS/422/1988
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of three extrasolar planets that transit their moderately bright (m_V_=12-13) host stars. WASP-44b is a 0.89-M_Jup_ planet in a 2.42-day orbit around a G8V star. WASP-45b is a 1.03-M_Jup_ planet which passes in front of the limb of its K2V host star every 3.13-days. Weak CaII H&K emission seen in the spectra of WASP-45 suggests that the star is chromospherically active. WASP-46b is a 2.10-M_Jup_ planet in a 1.43-day orbit around a G6V star. Rotational modulation of the light curves of WASP-46 and weak CaII H&K emission in its spectra show the star to be photospherically and chromospherically active.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/1185
- Title:
- Three transits of the exoplanet TrES-2
- Short Name:
- J/ApJ/664/1185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Of the nearby transiting exoplanets that are amenable to detailed study, TrES-2 is both the most massive and the one with the largest impact parameter. We present z-band photometry of three transits of TrES-2. We improve on the estimates of the planetary, stellar, and orbital parameters, in conjunction with the spectroscopic analysis of the host star by Sozzetti and coworkers. We find the planetary radius to be Rp=1.222+/-0.038R_Jup_ and the stellar radius to be R*=1.003+/-0.027R_{sun}_. The quoted uncertainties include the systematic error due to the uncertainty in the stellar mass (M*=0.980+/-0.062 M_{sun}_) The timings of the transits have an accuracy of 25s and are consistent with a uniform period, thus providing a baseline for future observations with the NASA Kepler satellite, whose field of view will include TrES-2.
- ID:
- ivo://CDS.VizieR/J/ApJS/230/16
- Title:
- 05 through L3 empirical stellar spectra from SDSS
- Short Name:
- J/ApJS/230/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a library of empirical stellar spectra created using spectra from the Sloan Digital Sky Survey's Baryon Oscillation Spectroscopic Survey. The templates cover spectral types O5 through L3, are binned by metallicity from -2.0dex through +1.0dex, and are separated into main-sequence (dwarf) stars and giant stars. With recently developed M dwarf metallicity indicators, we are able to extend the metallicity bins down through the spectral subtype M8, making this the first empirical library with this degree of temperature and metallicity coverage. The wavelength coverage for the templates is from 3650 to 10200{AA} at a resolution of better than R~2000. Using the templates, we identify trends in color space with metallicity and surface gravity, which will be useful for analyzing large data sets from upcoming missions like the Large Synoptic Survey Telescope. Along with the templates, we are releasing a code for automatically (and/or visually) identifying the spectral type and metallicity of a star.
