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- ID:
- ivo://CDS.VizieR/J/ApJ/522/113
- Title:
- 1Jy IRAS galaxies optical spectroscopy
- Short Name:
- J/ApJ/522/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper discusses the optical spectroscopic properties of the IRAS 1Jy sample (f_60_>1Jy) of ultraluminous infrared galaxies (ULIGs: L_IR_>10^12^L_{sun}; H_0_=75km/s/Mpc and q_0_=0). One hundred eight of the 118 1Jy ULIGs have been observed at {Delta}{lambda}=8.3{AA} resolution over the wavelength range ~4500-8900{AA}. These data are combined with large, previously published sets of optical spectroscopic data of lower luminosity infrared galaxies to look for systematic trends with infrared luminosity over the luminosity range L_IR_~10^10.5^-10^13^L_{sun}_.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/L89
- Title:
- Kapteyn's star spectroscopic measurements
- Short Name:
- J/MNRAS/443/L89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this paper, we investigate the radial velocity variations of Kapteyn's star, which is both a sub-dwarf M-star and the nearest halo object to the Sun. The observations comprise archival and new HARPS, HIRES and PFS Doppler measurements. Two Doppler signals are detected at periods of 48 and 120 days using likelihood periodograms and a Bayesian analysis of the data. Using the same techniques, the activity indices and archival ASAS-3 photometry show evidence for low-level activity periodicities of the order of several hundred days. However, there are no significant correlations with the radial velocity variations on the same time-scales. The inclusion of planetary Keplerian signals in the model results in levels of correlated and excess white noise that are remarkably low compared to younger G, K and M dwarfs. We conclude that Kapteyn's star is most probably orbited by two super-Earth mass planets, one of which is orbiting in its circumstellar habitable zone, becoming the oldest potentially habitable planet known to date. The presence and long-term survival of a planetary system seems a remarkable feat given the peculiar origin and kinematic history of Kapteyn's star. The detection of super-Earth mass planets around halo stars provides important insights into planet-formation processes in the early days of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/AJ/140/390
- Title:
- Karhunen-Loeve transform of SDSS QSOs
- Short Name:
- J/AJ/140/390
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Karhunen-Loeve (KL) transform can compactly represent the information contained in large, complex datasets, cleanly eliminating noise from the data and identifying elements of the dataset with extreme or inconsistent characteristics. We develop techniques to apply the KL transform to the 4000-5700{AA} region of 9800 QSO spectra with z<0.619 from the SDSS archive. Up to 200 eigenspectra are needed to fully reconstruct the spectra in this sample to the limit of their signal-to-noise (S/N). We propose a simple formula for selecting the optimum number of eigenspectra to use to reconstruct any given spectrum, based on the S/N of the spectrum, but validated by formal cross-validation tests.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/14
- Title:
- KASI-Yonsei Deep Imaging Survey of Clusters (KYDISC)
- Short Name:
- J/ApJS/237/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the KASI-Yonsei Deep Imaging Survey of Clusters targeting 14 clusters at 0.015<~z<~0.144 using the Inamori Magellan Areal Camera and Spectrograph on the 6.5m Magellan Baade telescope and the MegaCam on the 3.6m Canada-France-Hawaii Telescope. We provide a catalog of cluster galaxies that lists magnitudes, redshifts, morphologies, bulge-to-total ratios, and local density. Based on the 1409 spectroscopically confirmed cluster galaxies brighter than -19.8 in the r band, we study galaxy morphology, color, and visual features generated by galaxy mergers. We see a clear trend between morphological content and cluster velocity dispersion, which was not presented by previous studies using local clusters. Passive spirals are preferentially found in a highly dense region (i.e., cluster center), indicating that they have gone through environmental quenching. In deep images ({mu}_r'_~27mag/arcsec^2^), 20% of our sample shows signatures of recent mergers, which is not expected from theoretical predictions and a low frequency of ongoing mergers in our sample (~4%). Such a high fraction of recent mergers in the cluster environment supports a scenario that the merger events that made the features have preceded the galaxy accretion into the cluster environment. We conclude that mergers affect a cluster population mainly through the preprocessing of recently accreted galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/540/1016
- Title:
- K-band & NICMOS photometry of Trapezium Cluster
- Short Name:
- J/ApJ/540/1016
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained images of the Trapezium Cluster (140"x140"; 0.3pc x 0.3pc) with the Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer (NICMOS). Combining these data with new ground-based K-band spectra (R=800) and existing spectral types and photometry, we have constructed an H-R diagram and used it and other arguments to infer masses and ages.
- ID:
- ivo://CDS.VizieR/J/ApJ/748/93
- Title:
- K-band spectra for 133 nearby M dwarfs
- Short Name:
- J/ApJ/748/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present K-band spectra for 133 nearby (d < 33 pc) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these spectra, we measure equivalent widths of the Ca and Na lines, and a spectral index quantifying the absorption due to H_2_O opacity (the H_2_O-K2 index). Using empirical spectral type standards and synthetic models, we calibrate the H_2_O-K2 index as an indicator of an M dwarf's spectral type and effective temperature. We also present a revised relationship that estimates the [Fe/H] and [M/H] metallicities of M dwarfs from their Na I, Ca I, and H_2_O-K2 measurements. Comparisons to model atmosphere provide a qualitative validation of our approach, but also reveal an overall offset between the atomic line strengths predicted by models as compared to actual observations. Our metallicity estimates also reproduce expected correlations with Galactic space motions and H{alpha} emission line strengths, and return statistically identical metallicities for M dwarfs within a common multiple system. Finally, we find systematic residuals between our H_2_O-based spectral types and those derived from optical spectral features with previously known sensitivity to stellar metallicity, such as TiO, and identify the CaH1 index as a promising optical index for diagnosing the metallicities of near-solar M dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/510/A19
- Title:
- K-band spectra of 6 LMC globular clusters
- Short Name:
- J/A+A/510/A19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Current stellar population models have arguably the largest uncertainties in the near-IR wavelength range, partly due to a lack of large and well calibrated empirical spectral libraries. In this paper we present a project whose aim it is to provide the first library of luminosity weighted integrated near-IR spectra of globular clusters to be used to test the current stellar population models and serve as calibrators for future ones. Our pilot study presents spatially integrated K-band spectra of three old (>=10Gyr) and metal poor ([Fe/H]~-1.4), and three intermediate age (1-2Gyr) and more metal rich ([Fe/H]~-0.4) globular clusters in the LMC.
- ID:
- ivo://CDS.VizieR/J/AJ/121/97
- Title:
- K-band spectroscopy of ULIRGs
- Short Name:
- J/AJ/121/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared spectroscopy for a complete sample of 33 ultraluminous infrared galaxies at a resolution of R~1000. Most of the wavelength range from 1.80-2.20{mu}m in the rest frame is covered, including the Pa{alpha} and Br{gamma} hydrogen recombination lines, and the molecular hydrogen vibration-rotation 1-0 S(1) and S(3) lines. Other species, such as He I, [Fe II], and [Si VI] appear in the spectra as well, in addition to a number of weaker molecular hydrogen lines. Nuclear extractions for each of the individual galaxies are presented here, along with spectra of secondary nuclei, where available. The Pa{alpha} emission is seen to be highly concentrated on the nuclei, typically with very little emission extending beyond a radius of 1kpc. This survey was carried out primarily to search for signatures of active nuclei via velocity-broadened hydrogen recombination or the presence of the [Si VI] coronal line. These signatures are rare in the present sample, occurring in only two of the 33 galaxies. The extinction to the hydrogen recombination lines is investigated via the Pa{alpha}/Br{gamma} line ratio. It is found that visual extinctions to the nuclei in excess of 10mag are relatively common among ULIRGs and that visual extinctions greater than 25mag are necessary to conceal a QSO emitting half the total bolometric luminosity. The ionized hydrogen regions in many ULIRGs are sufficiently obscured that dust-enshrouded active galactic nuclei would remain hidden at 2{mu}m at the current level of sensitivity. The vibration-rotation lines of molecular hydrogen appear to be predominantly thermal in origin, with effective temperatures generally around 2200K. The relative nuclear velocities between double nucleus ULIRGs are investigated, through which it is inferred that the maximum deprojected velocity difference is ~200km.s-1. This figure is lower than the velocities predicted by physical models of strong interactions/mergers of large, gas-rich galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A110
- Title:
- K band spectrum of beta Pictoris b
- Short Name:
- J/A+A/633/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Beta Pictoris is arguably one of the most studied stellar systems outside of our own. Some 30 years of observations have revealed a highly-structured circumstellar disk, with rings, belts, and a giant planet: beta Pictoris b. However very little is known about how this system came into being. Our objective is to estimate the C/O ratio in the atmosphere of {beta} Pictoris b and obtain an estimate of the dynamical mass of the planet, as well as to refine its orbital parameters using high-precision astrometry. We used the GRAVITY instrument with the four 8.2m telescopes of the Very Large Telescope Interferometer to obtain K-band spectro-interferometric data on {beta} Pic b. We extracted a medium resolution (R=500) K-band spectrum of the planet and a high- precision astrometric position. We estimated the planetary C/O ratio using two different approaches (forward modeling and free retrieval) from two different codes (ExoREM and petitRADTRANS, respectively). Finally, we used a simplified model of two formation scenarios (gravitational collapse and core-accretion) to determine which can best explain the measured C/O ratio. Our new astrometry disfavors a circular orbit for beta Pic b (e=0.15^+0.05^_-0.04_). Combined with previous results and with Hipparcos/GAIA measurements, this astrometry points to a planet mass of M=12.7+/-2.2M_{Jup}_. This value is compatible with the mass derived with the free-retrieval code petitRADTRANS using spectral data only. The forward modeling and free-retrieval approches yield very similar results regarding the atmosphere of beta Pic b. In particular, the C/O ratios derived with the two codes are identical (0.43+/-0.05 vs $0.43^+0.04^_-0.03_). We argue that if the stellar C/O in beta Pic is Solar, then this combination of a very high mass and a low C/O ratio for the planet suggests a formation through core-accretion, with strong planetesimal enrichment.
