- ID:
- ivo://CDS.VizieR/J/A+A/593/A5
- Title:
- Radial velocity fitting challenge dataset
- Short Name:
- J/A+A/593/A5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar signals are the main limitation for precise radial-velocity (RV) measurements. These signals arise from the photosphere of the stars. The m/s perturbation created by these signals prevents the detection and mass characterization of small-mass planetary candidates such as Earth-twins. Several methods have been proposed to mitigate stellar signals in RV measurements. However, without precisely knowing the stellar and planetary signals in real observations, it is extremely difficult to test the efficiency of these methods. The goal of the RV fitting challenge is to generate simulated RV data including stellar and planetary signals and to perform a blind test within the community to test the efficiency of the different methods proposed to recover planetary signals despite stellar signals. In this first paper, we describe the simulation used to model the measurements of the RV fitting challenge. Each simulated planetary system includes the signals from instrumental noise, stellar oscillations, granulation, supergranulation, stellar activity, and observed and simulated planetary systems. In addition to RV variations, this simulation also models the effects of instrumental noise and stellar signals on activity observables obtained by HARPS-type high-resolution spectrographs, that is, the calcium activity index log(R'HK),and the bisector span and full width at half maximum of the cross-correlation function. We publish the 15 systems used for the RV fitting challenge including the details about the planetary systems that were injected into each of them.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/436/1302
- Title:
- Radiation fields in star-forming galaxies
- Short Name:
- J/MNRAS/436/1302
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a library of diffuse stellar radiation fields in spiral galaxies derived using calculations of the transfer of stellar radiation from the main morphological components - discs, thin discs and bulges - through the dusty interstellar medium. These radiation fields are self-consistent with the solutions for the integrated panchromatic spectral energy distributions (SEDs) previously presented using the same model. Because of this, observables calculated from the radiation fields, such as gamma-ray or radio emission, can be self-consistently combined with the solutions for the ultraviolet/optical/submillimeter SEDs, thus expanding the range of applicability of the radiation transfer model to a broader range of wavelengths and physical quantities.
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/2539
- Title:
- Radiation fields of the Milky Way
- Short Name:
- J/MNRAS/470/2539
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We provide a library for the ultraviolet - submillimetre (submm) interstellar radiation fields (ISRFs) of the Milky Way (MW), derived from modelling COBE, IRAS and Planck maps of the all-sky emission in the near-, mid-, far-infrared and submm. The library was produced using the axisymmetric radiative transfer model that we have previously implemented to model the panchromatic spectral energy distributions (SEDs) of star-forming galaxies in the nearby universe, but with a new methodology allowing for optimization of the radial and vertical geometry of stellar emissivity and dust opacity, as deduced from the highly resolved emission seen from the vantage point of the Sun.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A134
- Title:
- Radiative contribution from stripped stars
- Short Name:
- J/A+A/629/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stars stripped of their envelopes from interaction with a binary companion emit a significant fraction of their radiation as ionizing photons. They are potentially important stellar sources of ionizing radiation, however, they are still often neglected in spectral synthesis simulations or simulations of stellar feedback. In anticipating the large datasets of galaxy spectra from the upcoming James Webb Space Telescope, we modeled the radiative contribution from stripped stars by using detailed evolutionary and spectral models. We estimated their impact on the integrated spectra and specifically on the emission rates of HI-, HeI-, and HeII-ionizing photons from stellar populations. We find that stripped stars have the largest impact on the ionizing spectrum of a population in which star formation halted several Myr ago. In such stellar populations, stripped stars dominate the emission of ionizing photons, mimicking a younger stellar population in which massive stars are still present. Our models also suggest that stripped stars have harder ionizing spectra than massive stars. The additional ionizing radiation, with which stripped stars contribute affects observable properties that are related to the emission of ionizing photons from stellar populations. In co-eval stellar populations, the ionizing radiation from stripped stars increases the ionization parameter and the production efficiency of hydrogen ionizing photons. They also cause high values for these parameters for about ten times longer than what is predicted for massive stars. The effect on properties related to non-ionizing wavelengths is less pronounced, such as on the ultraviolet continuum slope or stellar contribution to emission lines. However, the hard ionizing radiation from stripped stars likely introduces a characteristic ionization structure of the nebula, which leads to the emission of highly ionized elements such as O^2+^ and C^3+^. We, therefore, expect that the presence of stripped stars affects the location in the BPT diagram and the diagnostic ratio of OIII to OII nebular emission lines. Our models are publicly available through CDS database and on the STARBURST99 website.
- ID:
- ivo://CDS.VizieR/J/A+A/466/641
- Title:
- Reaction rates of NeNa-MgAl chains in AGB stage
- Short Name:
- J/A+A/466/641
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We test the effect of proton-capture reaction rate uncertainties on the abundances of the Ne, Na, Mg and Al isotopes processed by the NeNa and MgAl chains during hot bottom burning (HBB) in asymptotic giant branch (AGB) stars of intermediate mass between 4 and 6M_{sun}_ and metallicities between Z=0.0001 and 0.02. We provide uncertainty ranges for the AGB stellar yields, for inclusion in galactic chemical evolution models, and indicate which reaction rates are most important and should be better determined.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/1
- Title:
- redMaPPer cluster catalog from DES data
- Short Name:
- J/ApJS/224/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe updates to the redMaPPer algorithm, a photometric red-sequence cluster finder specifically designed for large photometric surveys. The updated algorithm is applied to 150deg^2^ of Science Verification (SV) data from the Dark Energy Survey (DES), and to the Sloan Digital Sky Survey (SDSS) DR8 photometric data set. The DES SV catalog is locally volume limited and contains 786 clusters with richness {lambda}>20 (roughly equivalent to M_500c_>~10^14^h_70_^-1^M_{sun}_) and 0.2<z<0.9. The DR8 catalog consists of 26311 clusters with 0.08<z<0.6, with a sharply increasing richness threshold as a function of redshift for z>~0.35. The photometric redshift performance of both catalogs is shown to be excellent, with photometric redshift uncertainties controlled at the {sigma}_z_/(1+z)~0.01 level for z<~0.7 , rising to ~0.02 at z~0.9 in DES SV. We make use of Chandra and XMM X-ray and South Pole Telescope Sunyaev-Zeldovich data to show that the centering performance and mass-richness scatter are consistent with expectations based on prior runs of redMaPPer on SDSS data. We also show how the redMaPPer photo-z and richness estimates are relatively insensitive to imperfect star/galaxy separation and small-scale star masks.
- ID:
- ivo://CDS.VizieR/J/ApJ/785/104
- Title:
- redMaPPer. I. Algorithm applied to SDSS DR8
- Short Name:
- J/ApJ/785/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe redMaPPer, a new red sequence cluster finder specifically designed to make optimal use of ongoing and near-future large photometric surveys. The algorithm has multiple attractive features: (1) it can iteratively self-train the red sequence model based on a minimal spectroscopic training sample, an important feature for high-redshift surveys. (2) It can handle complex masks with varying depth. (3) It produces cluster-appropriate random points to enable large-scale structure studies. (4) All clusters are assigned a full redshift probability distribution P(z). (5) Similarly, clusters can have multiple candidate central galaxies, each with corresponding centering probabilities. (6) The algorithm is parallel and numerically efficient: it can run a Dark Energy Survey-like catalog in ~500 CPU hours. (7) The algorithm exhibits excellent photometric redshift performance, the richness estimates are tightly correlated with external mass proxies, and the completeness and purity of the corresponding catalogs are superb. We apply the redMaPPer algorithm to ~10000deg^2^ of SDSS DR8 data and present the resulting catalog of ~25000 clusters over the redshift range z{isin}[0.08,0.55]. The redMaPPer photometric redshifts are nearly Gaussian, with a scatter {sigma}_z_~0.006 at z~0.1, increasing to {sigma}_z_~0.02 at z~0.5 due to increased photometric noise near the survey limit. The median value for |{Delta}z|/(1+z) for the full sample is 0.006. The incidence of projection effects is low (<= 5%). Detailed performance comparisons of the redMaPPer DR8 cluster catalog to X-ray and Sunyaev-Zel'dovich catalogs are presented in a companion paper.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/35
- Title:
- Redshifts of lensed systems toward RXCJ2248.7-4431
- Short Name:
- J/ApJ/888/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an iterative method to construct a freeform lens model that self-consistently reproduces the sky positions, geometrically inferred redshifts, and relative brightnesses of all multiply lensed images toward a galaxy cluster. This method is applied to the cluster RXCJ2248.7-4431 (z=0.348) from the Hubble Frontier Fields program, toward which 10 multiply lensed sources with accurate spectroscopic redshifts and 6 others with inexact photometric redshifts have been identified. Using the spectroscopically secure systems to define an initial lens model, we compute the geometric redshifts of the photometric systems. We then iterate the lens model by incorporating the photometric systems at redshifts shifted by incremental amounts toward their geometric redshifts inferred from the previous step; on convergence, we find geometric redshifts in good agreement with the spectroscopically determined redshifts, but they can depart significantly from the photometrically determined redshifts. In the final lens model, all 16 lensed sources tightly follow the cosmological form of the angular diameter distance relation. Furthermore, although they are not used as model constraints, our lens model predicts relative brightnesses between image pairs for a given set of multiply lensed images in reasonable agreement with observations, thus providing independent validation of this model.
- ID:
- ivo://CDS.VizieR/J/A+A/515/A35
- Title:
- Reduction of integral-field spectrograph code P3D
- Short Name:
- J/A+A/515/A35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The reduction of integral-field spectrograph (IFS) data is demanding work. Many repetitive operations are required to convert raw data into, typically, a large number of spectra. This effort can be markedly simplified through the use of a tool or pipeline, which is designed to complete many of the repetitive operations without human interaction. Here we present our semi-automatic data-reduction tool P3D, which is designed to be used with fiber-fed IFSs. Important components of P3D include a novel algorithm for automatic finding and tracing of spectra on the detector and two methods of optimal spectrum extraction in addition to standard aperture extraction. P3D also provides tools to combine several images, perform wavelength calibration and flat field data. P3D is at the moment configured for four IFSs. To evaluate its performance, we tested the different components of the tool. For these tests we used both simulated and observational data. We demonstrate that a correction for so-called cross-talk due to overlapping spectra on the detector is required for three of the IFSs. Without such a correction, spectra will be inaccurate, in particular if there is a significant intensity gradient across the object. Our tests showed that P3D is able to produce accurate results. P3D is a highly general and freely available tool. It is easily extended to include improved algorithms, new visualization tools, and support for additional instruments. The program code can be downloaded from the P3D-project web site http://p3d.sourceforge.net.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/L14
- Title:
- Refracted light signals to discriminate exoplanets
- Short Name:
- J/ApJ/795/L14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a method to distinguish between cloudy, hazy, and clear sky (free of clouds and hazes) exoplanet atmospheres that could be applicable to upcoming large aperture space- and ground-based telescopes such as the James Webb Space Telescope (JWST) and the European Extremely Large Telescope (E-ELT). These facilities will be powerful tools for characterizing transiting exoplanets, but only after a considerable amount of telescope time is devoted to a single planet. A technique that could provide a relatively rapid means of identifying haze-free targets (which may be more valuable targets for characterization) could potentially increase the science return for these telescopes. Our proposed method utilizes broadband observations of refracted light in the out-of-transit spectrum. Light refracted through an exoplanet atmosphere can lead to an increase of flux prior to ingress and subsequent to egress. Because this light is transmitted at pressures greater than those for typical cloud and haze layers, the detection of refracted light could indicate a cloud- or haze-free atmosphere. A detection of refracted light could be accomplished in <10 hr for Jovian exoplanets with JWST and <5 hr for super-Earths/mini-Neptunes with E-ELT. We find that this technique is most effective for planets with equilibrium temperatures between 200 and 500 K, which may include potentially habitable planets. A detection of refracted light for a potentially habitable planet would strongly suggest the planet was free of a global cloud or haze layer, and therefore a promising candidate for follow-up observations.
