- ID:
- ivo://nasa.heasarc/tgs
- Title:
- EXOSAT TGS L and R Orders
- Short Name:
- TGS
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Spectra obtained using the EXOSAT transmission grating spectrometer, TGS. There are two databases TGS and TGS2 as follows: <pre> * TGS - the grating spectra averaged over the positive and negative orders * TGS2 - the postive and negative orders kept separate </pre> TGS provides a better overview of the spectrum, and is quicker to use with a spectral fitting program. This is the default that most users will want to use. Once a user has become more expert and wants to see, for example, if a subtle feature is present in both halves of the grating spectra, the user can access TGS2. This is a service provided by NASA HEASARC .
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- ID:
- ivo://nasa.heasarc/tgs2
- Title:
- EXOSAT TGS Spectra and Lightcurves
- Short Name:
- TGS2
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- Spectra obtained using the EXOSAT transmission grating spectrometer, TGS. There are two databases TGS and TGS2 as follows: <pre> * TGS - the grating spectra averaged over the positive and negative orders * TGS2 - the postive and negative orders kept separate </pre> TGS provides a better overview of the spectrum, and is quicker to use with a spectral fitting program. This is the default that most users will want to use. Once a user has become more expert and want to see, for example, if a subtle feature is present in both halves of the grating spectra, the user can access TGS2. This is a service provided by NASA HEASARC .
5893. EXOTOPO
- ID:
- ivo://geops.ipsl/exotopo/q/epn_core
- Title:
- EXOTOPO
- Short Name:
- exotopo.epn_core
- Date:
- 17 Jul 2024 15:24:58
- Publisher:
- IPSL/GEOPS
- Description:
- "The data consists in topographic maps of synthetic 3D bodies generated by a 3 parameters statistical model : the fractionally integrated flux (FiF) (Lavallee, D., Lovejoy, S., Schertzer, D., Ladoy, P. (1993). Nonlinear variability and landscape topography: analysis and simulation) adapted for spherical coordinates and topography (Landais, F., Schmidt, F., and Lovejoy, S, (2018) Topography of exoplanets, MNRAS). The 3 parameters are the following : H: degree of smoothness; C1: degree of intermittency; alpha: degree of multifractality; The service contains topographic maps (in Fits format) and texture maps (in png format)."
- ID:
- ivo://CDS.VizieR/J/A+A/430/911
- Title:
- Expansive components in HII regions
- Short Name:
- J/A+A/430/911
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the presence of low intensity high velocity components, which we have termed wing features in the integrated Halpha emission line profiles of the HII region populations of the spiral barred galaxies NGC 1530, NGC 3359 and NGC 6951. We find that more than a third of the HII region line profiles in each galaxy show these components.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/56
- Title:
- Experimental spectrum of methanol (CH_3_OH)
- Short Name:
- J/ApJ/795/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectrum of methanol (CH_3_OH) has been characterized between 214.6 and 265.4 GHz for astrophysically significant temperatures. Four hundred and eighty-six spectra with absolute intensity calibration recorded between 240 and 389 K provided a means for the calculation of the complete experimental spectrum (CES) of methanol as a function of temperature. The CES includes contributions from v_t_=3 and other higher states that are difficult to model quantum mechanically (QM). It also includes the spectrum of the ^13^C isotopologue in terrestrial abundance. In general the QM models provide frequencies that are within 1 MHz of their experimental values, but there are several outliers that differ by tens of MHz. As in our recent work on methanol in the 560-654 GHz region, significant intensity differences between our experimental intensities and cataloged values were found. In this work these differences are explored in the context of several QM analyses. The experimental results presented here are analyzed to provide a frequency point-by-point catalog that is well suited for the simulation of crowded and overlapped spectra. Additionally, a catalog in the usual line frequency, line strength, and lower state energy format is provided.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/11
- Title:
- Exploring 6 AGN dusty torus models. II.
- Short Name:
- J/ApJ/884/11
- Date:
- 04 Dec 2021
- Publisher:
- CDS
- Description:
- This is the second in a series of papers devoted to exploring a set of six dusty models of active galactic nuclei (AGN) with available spectral energy distributions. These models are the smooth torus by Fritz+ (2006MNRAS.366..767F), the clumpy torus by Nenkova+ (2008ApJ...685..147N and 2008ApJ...685..160N), the clumpy torus by Honig & Kishimoto (2010A&A...523A..27H), the two-phase torus by Siebenmorgen+ (2015A&A...583A.120S), the two-phase torus by Stalevski+ (2012MNRAS.420.2756S and 2016MNRAS.458.2288S), and the wind model by Honig & Kishimoto (2017ApJ...838L..20H). The first paper explores discrimination among models and the parameter restriction using synthetic spectra. Here we perform spectral fitting of a sample of 110 AGN drawn from the Swift/BAT survey with Spitzer/IRS spectroscopic data. The aim is to explore which is the model that describes better the data and the resulting parameters. The clumpy wind-disk model by Honig & Kishimoto provides good fits for ~50% of the sample, and the clumpy torus model by Nenkova+ is good at describing ~30% of the objects. The wind-disk model by Honig & Kishimoto is better for reproducing the mid-infrared spectra of type 1 Seyferts (with 60% of the type 1 Seyferts well reproduced by this model compared to the 10% well represented by the clumpy torus model by Nenkova+), while type 2 Seyferts are equally fitted by both models (roughly 40% of the type 2 Seyferts). Large residuals are found irrespective of the model used, indicating that the AGN dust continuum emission is more complex than predicted by the models or that the parameter space is not well sampled. We found that all the resulting parameters for our AGN sample are roughly constrained to 10%-20% of the parameter space. Contrary to what is generally assumed, the derived outer radius of the torus is smaller (reaching up to a factor of ~5 smaller for 10pc tori) for the smooth torus by Fritz+ and the two-phase torus by Stalevski+ than the one derived from the clumpy torus by Nenkova+ Covering factors and line-of-sight viewing angles strongly depend on the model used. The total dust mass is the most robust derived quantity, giving equivalent results for four of these models.
- ID:
- ivo://CDS.VizieR/J/ApJS/228/19
- Title:
- Exploring the SDSS data set. I. EMP & CV stars
- Short Name:
- J/ApJS/228/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for extremely metal-poor (EMP), carbon-enhanced metal-poor (CEMP), and cataclysmic variable (CV) stars using a new exploration tool based on linked scatter plots (LSPs). Our approach is especially designed to work with very large spectrum data sets such as the SDSS, LAMOST, RAVE, and Gaia data sets, and it can be applied to stellar, galaxy, and quasar spectra. As a demonstration, we conduct our search using the SDSS DR10 data set. We first created a 3326-dimensional phase space containing nearly 2 billion measures of the strengths of over 1600 spectral features in 569738 SDSS stars. These measures capture essentially all the stellar atomic and molecular species visible at the resolution of SDSS spectra. We show how LSPs can be used to quickly isolate and examine interesting portions of this phase space. To illustrate, we use LSPs coupled with cuts in selected portions of phase space to extract EMP stars, CEMP stars, and CV stars. We present identifications for 59 previously unrecognized candidate EMP stars and 11 previously unrecognized candidate CEMP stars. We also call attention to 2 candidate He II emission CV stars found by the LSP approach that have not yet been discussed in the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/608/405
- Title:
- Explosive yields of massive star (Z=0-Z_{sun}_)
- Short Name:
- J/ApJ/608/405
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new and homogeneous set of explosive yields for masses 13, 15, 20, 25, 30, and 35M_{sun}_ and metallicities Z=0, 10^-6^, 10^-4^, 10^-3^, 6x10^-3^, and 2x10^-2^. A wide network extending up to Mo has been used in all computations. We show that at low metallicities (Z<=10^-4^), the final yields do not depend significantly on the initial chemical composition of the models, so a scaled solar distribution may be safely assumed at all metallicities. Moreover, no elements above Zn are produced by any mass in the grid up to a metallicity ~10-3. These yields are available for any choice of the mass cut on request.
- ID:
- ivo://CDS.VizieR/J/AJ/161/26
- Title:
- EXPRES. II. HD 101501 photometry and radial velocity
- Short Name:
- J/AJ/161/26
- Date:
- 09 Mar 2022 22:00:00
- Publisher:
- CDS
- Description:
- By controlling instrumental errors to below 10cm/s, the EXtreme PREcision Spectrograph (EXPRES) allows for a more insightful study of photospheric velocities that can mask weak Keplerian signals. Gaussian processes (GP) have become a standard tool for modeling correlated noise in radial velocity data sets. While GPs are constrained and motivated by physical properties of the star, in some cases they are still flexible enough to absorb unresolved Keplerian signals. We apply GP regression to EXPRES radial velocity measurements of the 3.5Gyr old chromospherically active Sun-like star, HD101501. We obtain tight constraints on the stellar rotation period and the evolution of spot distributions using 28 seasons of ground-based photometry, as well as recent Transiting Exoplanet Survey Satellite data. Light-curve inversion was carried out on both photometry data sets to reveal the spot distribution and spot evolution timescales on the star. We find that the >5m/s rms radial velocity variations in HD101501 are well modeled with a GP stellar activity model without planets, yielding a residual rms scatter of 45cm/s. We carry out simulations, injecting and recovering signals with the GP framework, to demonstrate that high-cadence observations are required to use GPs most efficiently to detect low-mass planets around active stars like HD101501. Sparse sampling prevents GPs from learning the correlated noise structure and can allow it to absorb prospective Keplerian signals. We quantify the moderate to high-cadence monitoring that provides the necessary information to disentangle photospheric features using GPs and to detect planets around active stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/32
- Title:
- Extended abundance analysis of cool stars
- Short Name:
- J/ApJS/225/32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of uniformly determined stellar properties and abundances for 1615 F, G, and K stars using an automated spectral synthesis modeling procedure. All stars were observed using the HIRES spectrograph at Keck Observatory. Our procedure used a single line list to fit model spectra to observations of all stars to determine effective temperature, surface gravity, metallicity, projected rotational velocity, and the abundances of 15 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Ni, and Y). Sixty percent of the sample had Hipparcos parallaxes and V-band photometry, which we combined with the spectroscopic results to obtain mass, radius, and luminosity. Additionally, we used the luminosity, effective temperature, metallicity and {alpha}-element enhancement to interpolate in the Yonsei-Yale isochrones to derive mass, radius, gravity, and age ranges for those stars. Finally, we determined new relations between effective temperature and macroturbulence for dwarfs and subgiants. Our analysis achieved precisions of 25K in T_eff_, 0.01dex in [M/H], 0.028dex for logg, and 0.5km/s in vsini based on multiple observations of the same stars. The abundance results were similarly precise, between ~0.01 and ~0.04dex, though trends with respect to T_eff_ remained for which we derived empirical corrections. The trends, though small, were much larger than our uncertainties and are shared with published abundances. We show that changing our model atmosphere grid accounts for most of the trend in [M/H] between 5000 and 5500K, indicating a possible problem with the atmosphere models or opacities.