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891. Orbits of spectro. binaries with CHARA Array. III.
ID:
ivo://CDS.VizieR/J/AJ/160/58
Title:
Orbits of spectro. binaries with CHARA Array. III.
Short Name:
J/AJ/160/58
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the visual orbits of two long-period spectroscopic binary stars, HD8374 and HD24546, using interferometric observations acquired with the Center for High Angular Resolution Astronomy (CHARA) Array and the Palomar Testbed Interferometer. We also obtained new radial velocities from echelle spectra using the APO 3.5m and Fairborn 2.0 telescopes. By combining the visual and spectroscopic observations, we solve for the full, three-dimensional orbits and determine the stellar masses and distances to within 3% uncertainty. We then estimate the effective temperature and radius of each component star through Doppler tomography and spectral energy distribution analyses, in order to compare the observed stellar parameters to the predictions of stellar evolution models. For HD8374, we find masses of M1=1.636{+/-}0.050M{sun} and M2=1.587{+/-}0.049M{sun}, radii of R1=1.84{+/-}0.05R{sun} and R2=1.66{+/-}0.12R{sun}, temperatures of Teff_1_=7280{+/-}110K and Teff-2-=7280{+/-}120K, and an estimated age of 1.0Gyr. For HD24546, we find masses of M1=1.434{+/-}0.014M{sun} and M2=1.409{+/-}0.014M{sun}, radii of R_1_=1.67{+/-}0.06R{sun} and R_2_=1.60{+/-}0.10R{sun}, temperatures of Teff_1_=6790{+/-}120K and Teff_2_=6770{+/-}90K, and an estimated age of 1.4Gyr. HD24546 is therefore too old to be a member of the Hyades cluster, despite its physical proximity to the group.
892. Orion stars CO-added IRAS fluxes catalog
ID:
ivo://CDS.VizieR/J/ApJS/78/239
Title:
Orion stars CO-added IRAS fluxes catalog
Short Name:
J/ApJS/78/239
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalog of co-added IRAS fluxes for the pre-main-sequence objects in the Herbig-Bell catalog (HBC) is presented. This catalog doubles the number of HBC stars with detected IRAS fluxes and provides improved flux values for the previously known sources. Noise levels are given for all HBC fields in each band, permitting upper limits to be estimated for all undetected sources.
893. O2 signature in thin and thick O2-H2O ices
ID:
ivo://CDS.VizieR/J/A+A/620/A46
Title:
O2 signature in thin and thick O2-H2O ices
Short Name:
J/A+A/620/A46
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we investigate the detectability of the molecular oxygen in icy dust grain mantles towards astronomical objects. We present a systematic set of experiments with O_2_-H_2_O ice mixtures designed to disentangle how the molecular ratio affects the O_2_ signature in the mid- and near-infrared spectral regions. All the experiments were conducted in a closed-cycle helium cryostat coupled to a Fourier transform infrared spectrometer. The ice mixtures comprise varying thicknesses from 8x10^-3^ to 3um. The absorption spectra of the O_2_-H_2_O mixtures are also compared to the one of pure water. In addition, the possibility to detect the O_2_ in icy bodies and in the interstellar medium is discussed. We are able to see the O_2_ feature at 1551cm^-1^ even for the most diluted mixture of H_2_O:O_2_=9:1, comparable to a ratio of O_2_/H_2_O=10% which has already been detected in situ in the coma of the comet 67P/Churyumov-Gerasimenko. We provide an estimate for the detection of O_2_ with the future mission of the James Webb Space Telescope (JWST).
894. OSIRIS K-band spectroscopy of {kappa} Andromedae b
ID:
ivo://CDS.VizieR/J/AJ/160/207
Title:
OSIRIS K-band spectroscopy of {kappa} Andromedae b
Short Name:
J/AJ/160/207
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present moderate-resolution (R~4000) K-band spectra of the "super- Jupiter," {kappa}-Andromedae-b. The data were taken with the OSIRIS integral field spectrograph at Keck Observatory. The spectra reveal resolved molecular lines from H2O and CO, and are compared to a custom PHOENIX atmosphere model grid appropriate for young planetary-mass objects. We fit the data using a Markov chain Monte Carlo forward-modeling method. Using a combination of our moderate-resolution spectrum and low-resolution, broadband data from the literature, we derive an effective temperature of Teff=1950-2150K, a surface gravity of logg=3.5--4.5, and a metallicity of [M/H]=-0.2--0.0. These values are consistent with previous estimates from atmospheric modeling and the currently favored young age of the system (<50Myr). We derive a C/O ratio of 0.70_-0.24_^+0.09^ for the source, broadly consistent with the solar C/O ratio. This, coupled with the slightly subsolar metallicity, implies a composition consistent with that of the host star, and is suggestive of formation by a rapid process. The subsolar metallicity of {kappa}-Andromedae-b is also consistent with predictions of formation via gravitational instability. Further constraints on formation of the companion will require measurement of the C/O ratio of {kappa}-Andromedae-A. We also measure the radial velocity of {kappa}-Andromedae-b for the first time, with a value of -1.4{+/-}0.9km/s relative to the host star. We find that the derived radial velocity is consistent with the estimated high eccentricity of {kappa}-Andromedae-b.
895. Outer Galaxy IRAS sources and 12CO emission
ID:
ivo://CDS.VizieR/J/A+A/399/1083
Title:
Outer Galaxy IRAS sources and 12CO emission
Short Name:
J/A+A/399/1083
Date:
21 Oct 2021
Publisher:
CDS
Description:
We examined all of the IRAS sources within the Five College Radio Astronomy Observatory (FCRAO) Outer Galaxy Survey (OGS) region for associated ^12^CO emission (as accounted for in the Brunt, Kerton, and Pomerleau (2003, in press) catalogue of ^12^CO emission in the OGS). Table 1 provides a ranked listing of IRAS-CO associations and Table 2 provides a listing of those IRAS sources with no CO associations. In order to rank the various IRAS-CO associations we examined the association of random lines of sight with CO emission in the OGS. The resulting expectation numbers are provided to the reader in Table A1.
896. Outflows and bubbles in Taurus
ID:
ivo://CDS.VizieR/J/ApJS/219/20
Title:
Outflows and bubbles in Taurus
Short Name:
J/ApJS/219/20
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have identified outflows and bubbles in the Taurus molecular cloud based on the ~100deg^2^ Five College Radio Astronomy Observatory ^12^CO(1-0) and ^13^CO(1-0) maps and the Spitzer young stellar object catalogs. In the main 44deg^2^ area of Taurus, we found 55 outflows, of which 31 were previously unknown. We also found 37 bubbles in the entire 100deg^2^ area of Taurus, none of which had been found previously. The total kinetic energy of the identified outflows is estimated to be ~3.9x10^45^erg, which is 1% of the cloud turbulent energy. The total kinetic energy of the detected bubbles is estimated to be ~9.2x10^46^erg, which is 29% of the turbulent energy of Taurus. The energy injection rate from the outflows is ~1.3x10^33^erg/s, which is 0.4-2 times the dissipation rate of the cloud turbulence. The energy injection rate from bubbles is ~6.4x10^33^erg/s, which is 2-10 times the turbulent dissipation rate of the cloud. The gravitational binding energy of the cloud is ~1.5x10^48^erg, that is, 385 and 16 times the energy of outflows and bubbles, respectively. We conclude that neither outflows nor bubbles can provide sufficient energy to balance the overall gravitational binding energy and the turbulent energy of Taurus. However, in the current epoch, stellar feedback is sufficient to maintain the observed turbulence in Taurus.
897. Overdensities of submm-galaxies around AGNs
ID:
ivo://CDS.VizieR/J/MNRAS/469/4565
Title:
Overdensities of submm-galaxies around AGNs
Short Name:
J/MNRAS/469/4565
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate extremely luminous dusty galaxies in the environments around Wide-field Infrared Survey Explorer (WISE)-selected hot dust-obscured galaxies (Hot DOGs) and WISE/radio-selected active galactic nuclei (AGNs) at average redshifts of z=2.7 and 1.7, respectively. Previous observations have detected overdensities of companion submillimetre-selected sources around 10 Hot DOGs and 30 WISE/radio AGNs, with overdensities of ~2-3 and ~5-6, respectively. We find that the space densities in both samples to be overdense compared to normal star-forming galaxies and submillimetre galaxies (SMGs) in the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) Cosmology Legacy Survey (S2CLS). Both samples of companion sources have consistent mid-infrared (mid-IR) colours and mid-IR to submm ratios as SMGs. The brighter population around WISE/radio AGNs could be responsible for the higher overdensity reported. We also find that the star formation rate densities are higher than the field, but consistent with clusters of dusty galaxies. WISE-selected AGNs appear to be good signposts for protoclusters at high redshift on arcmin scales. The results reported here provide an upper limit to the strength of angular clustering using the two-point correlation function. Monte Carlo simulations show no angular correlation, which could indicate protoclusters on scales larger than the SCUBA-2 1.5-arcmin scale maps.
898. 4 oxygen-rich evolved stars NH3 spectra
ID:
ivo://CDS.VizieR/J/A+A/612/A48
Title:
4 oxygen-rich evolved stars NH3 spectra
Short Name:
J/A+A/612/A48
Date:
21 Oct 2021
Publisher:
CDS
Description:
The circumstellar ammonia (NH_3_) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH_3_ abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry. We would like to characterise the spatial distribution and excitation of NH_3_ in the oxygen-rich circumstellar envelopes (CSEs) of four diverse targets: IK Tau, VY CMa, OH 231.8+4.2, and IRC +10420. We observed NH_3_ emission from the ground state in the inversion transitions near 1.3cm with the Very Large Array (VLA) and submillimetre rotational transitions with the Heterodyne Instrument for the Far-Infrared (HIFI) aboard Herschel Space Observatory from all four targets. For IK Tau and VY CMa, we observed NH_3_ rovibrational absorption lines in 2 band near 10.5um with the Texas Echelon Cross Echelle Spectrograph (TEXES) at the NASA Infrared Telescope Facility (IRTF).We also attempted to search for the rotational transition within the excited vibrational state (v_2_=1) near 2mm with the IRAM 30m Telescope. Non-LTE radiative transfer modelling, including radiative pumping to the vibrational state, was carried out to derive the radial distribution of NH_3_ in the CSEs of these targets. We detected NH_3_ inversion and rotational emission in all four targets. IK Tau and VY CMa show blueshifted absorption in the rovibrational spectra. We did not detect vibrationally excited rotational transition from IK Tau. Spatially resolved VLA images of IK Tau and IRC +10420 show clumpy emission structures; unresolved images of VY CMa and OH 231.8+4.2 indicate that the spatial-kinematic distribution of NH_3_ is similar to that of assorted molecules, such as SO and SO2, that exhibit localised and clumpy emission. Our modelling shows that the NH_3_ abundance relative to molecular hydrogen is generally of the order of 10^-7^, which is a few times lower than previous estimates that were made without considering radiative pumping and is at least ten times higher than that in the carbon-rich CSE of IRC +10216. NH_3_ in OH 231.8+4.2 and IRC +10420 is found to emit in gas denser than the ambient medium. Incidentally, we also derived a new period of IK Tau from its V-band light curve. NH_3_ is again detected in very high abundance in evolved stars, especially the oxygen-rich ones. Its emission mainly arises from localised spatial-kinematic structures that are probably denser than the ambient gas. Circumstellar shocks in the accelerated wind may contribute to the production of NH_3_. Future mid-infrared spectroscopy and radio imaging studies are necessary to constrain the radii and physical conditions of the formation regions of NH_3_.
899. Pa{alpha} (1.87um) LF of HII regions in 12 galaxies
ID:
ivo://CDS.VizieR/J/ApJ/772/27
Title:
Pa{alpha} (1.87um) LF of HII regions in 12 galaxies
Short Name:
J/ApJ/772/27
Date:
21 Oct 2021
Publisher:
CDS
Description:
The H II region luminosity function (LF) is an important tool for deriving the birthrates and mass distribution of OB associations and is an excellent tracer of the newly formed massive stars and associations. To date, extensive work (predominantly in H{alpha}) has been done from the ground, which is hindered by dust extinction and the severe blending of adjacent (spatially or in projection) H II regions. Reliably measuring the properties of H II regions requires a linear resolution <40pc, but analyses satisfying this requirement have been done only in a handful of galaxies, so far. As the first space-based work using a galaxy sample, we have selected 12 galaxies from our HST/NICMOS Pa{alpha} survey and studied the LF and size distribution of H II regions both in individual galaxies and cumulatively, using a virtually extinction-free tracer of the ionizing photon rate. The high angular resolution and low sensitivity to diffuse emission of NICMOS also offer an advantage over ground-based imaging by enabling a higher degree of de-blending of the H II regions. We do not confirm the broken power-law LFs found in ground-based studies. Instead, we find that the LFs, both individual and co-added, follow a single power law dN(L)/dlnL{propto}L^-1^, are consistent with the mass function of star clusters in nearby galaxies, and are in agreement with the results of the existing analyses with Hubble Space Telescope (HST) data. The individual and co-added size distributions of H II regions are both roughly consistent with dN(D)/dlnD{propto}D^-3^, but the power-law scaling is probably contaminated by blended regions or complexes.
900. Pa-beta, Ha and attenuation in NGC5194 & NGC6946
ID:
ivo://CDS.VizieR/J/ApJ/892/23
Title:
Pa-beta, Ha and attenuation in NGC5194 & NGC6946
Short Name:
J/ApJ/892/23
Date:
19 Jan 2022 08:58:18
Publisher:
CDS
Description:
We combine Hubble Space Telescope Paschen {beta} (Pa{beta}) imaging with ground-based, previously published H{alpha} maps to estimate the attenuation affecting H{alpha}, A(H{alpha}), across the nearby, face-on galaxies NGC 5194 and NGC 6946. We estimate A(H{alpha}) in ~2000 independent 2" ~75pc diameter apertures in each galaxy, spanning out to a galactocentric radius of almost 10kpc. In both galaxies, A(H{alpha}) drops with radius, with a bright, high-attenuation inner region, though in detail the profiles differ between the two galaxies. Regions with the highest attenuation-corrected H{alpha} luminosity show the highest attenuation, but the observed H{alpha} luminosity of a region is not a good predictor of attenuation in our data. Consistent with much previous work, the IR-to-H{alpha} color does a good job of predicting A(H{alpha}). We calculate the best-fit empirical coefficients for use combining H{alpha} with 8, 12, 24, 70, or 100{mu}m to correct for attenuation. These agree well with previous work, but we also measure significant scatter around each of these linear relations. The local atomic plus molecular gas column density, N(H), also predicts A(H{alpha}) well. We show that a screen with magnitude ~0.2 times that expected for a Milky Way gas-to-dust value does a reasonable job of explaining A(H{alpha}) as a function of N(H). This could be expected if only ~40% of gas and dust directly overlap regions of H{alpha} emission.