- ID:
- ivo://CDS.VizieR/J/A+A/643/A146
- Title:
- The solar gravitational redshift
- Short Name:
- J/A+A/643/A146
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The General Theory of Relativity predicts the redshift of spectral lines in the solar photosphere, as a consequence of the gravitational potential of the Sun. This effect can be measured from a solar disk-integrated flux spectrum of the Sun's reflected light on solar system bodies. The laser frequency comb (LFC) calibration system attached to the HARPS spectrograph offers the possibility to perform an accurate measurement of the solar gravitational redshift (GRS) by observing the Moon or other solar system bodies. We have analysed the line shift observed in Fe absorption lines from five high-quality HARPS-LFC spectra of the Moon. We select an initial sample of 326 photospheric Fe lines in the spectral range 476-585nm and measure their line positions and equivalent widths (EWs). Accurate line shifts are derived from the wavelength position of the core of the lines compared with the laboratory wavelengths of Fe lines. We also use a CO^5^BOLD 3D hydrodynamical model atmosphere of the Sun to compute 3D synthetic line profiles of a subsample of about 200 spectral Fe lines centred at their laboratory wavelengths. We fit the observed relatively weak spectral Fe lines (with EW<180m{AA}) with the 3D synthetic profiles. Convective motions in the solar photosphere do not affect the line cores of Fe lines stronger than about 150m{AA}. In our sample, only 15 FeI lines have EWs in the range 150<EW(m{AA})<550, providing a measurement of the solar GRS at 639+/-14m/s, consistent with the expected theoretical value on Earth of 633.1m/s. A final sample of about 98 weak Fe lines with EW<180m{AA} allows us to derive a mean global line shift of 638+/-6m/s in agreement with the theoretical solar GRS. These are the most accurate measurements of the solar GRS so far. Ultrastable spectrographs calibrated with the LFC over a larger spectral range, such as HARPS or ESPRESSO, together with a further improvement on the laboratory wavelengths, could provide a more robust measurement of the solar GRS and further tests for the 3D hydrodynamical models.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/161/172
- Title:
- The Solar Neighborhood. XLVII. Mdwarfs with STIS
- Short Name:
- J/AJ/161/172
- Date:
- 18 Jan 2022
- Publisher:
- CDS
- Description:
- We use HST/STIS optical spectroscopy of 10 M-dwarfs in five closely separated binary systems to test models of M-dwarf structure and evolution. Individual dynamical masses ranging from 0.083 to 0.405M{sun} for all stars are known from previous work. We first derive temperature, radius, luminosity, surface gravity, and metallicity by fitting the BT-Settl atmospheric models. We verify that our methodology agrees with empirical results from long-baseline optical interferometry for stars of similar spectral types. We then test whether or not evolutionary models can predict those quantities given the stars' known dynamical masses and the conditions of coevality and equal metallicity within each binary system. We apply this test to five different evolutionary model sets: the Dartmouth models, the MESA/MIST models, the models of Baraffe et al., the PARSEC models, and the YaPSI models. We find marginal agreement between evolutionary model predictions and observations, with few cases where the models respect the condition of coevality in a self-consistent manner. We discuss the pros and cons of each family of models and compare their predictive power.
- ID:
- ivo://CDS.VizieR/J/ApJS/207/13
- Title:
- The spectrum and term analysis of V II
- Short Name:
- J/ApJS/207/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectrum and extended term analysis of V II are presented. Fourier transform spectrometry was used to record high resolution spectra of singly ionized vanadium in the region 1492-5800 {AA} (67020-17260/cm) with vanadium-neon and vanadium-argon hollow cathode lamps as sources. The wavenumber uncertainty for the center of gravity of the strongest lines is typically 0.002/cm, an improvement of an order of magnitude over previous measurements. Most of the lines exhibit partly resolved hyperfine structure. The V II energy levels in the 1985 compilation of Sugar and Corliss have been confirmed and revised, with the exception of the high-lying 4f levels and eight of the lower levels. Thirty-nine of the additional eighty-five high levels published by Iglesias et al. (1988, Publicaciones del Instituto Optica Daza de Valdes Madrid, 47, 1) have also been confirmed and revised, and three of their missing levels have been found. The energy uncertainty of the revised levels has been reduced by about an order of magnitude. In total, 176 even levels and 233 odd levels are presented.
2884. The Spectrum of IC 418
- ID:
- ivo://CDS.VizieR/J/PASP/106/745
- Title:
- The Spectrum of IC 418
- Short Name:
- J/PASP/106/745
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed high spectral resolution study of the spectrum of IC 418 is made for the region 3650{AA} to 10050{AA}, using the Hamilton echelle spectrograph of Lick Observatory, and of the UV spectral region with archival International Ultraviolet Explorer (IUE) data.
- ID:
- ivo://CDS.VizieR/J/ApJ/693/1821
- Title:
- The Spitzer infrared nearby galaxies survey
- Short Name:
- J/ApJ/693/1821
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution mid-infrared spectra are presented for 155 nuclear and extranuclear regions from the Spitzer Infrared Nearby Galaxies Survey (SINGS). The fluxes for nine atomic forbidden and three molecular hydrogen mid-infrared emission lines are also provided, along with upper limits in key lines for infrared-faint targets. The SINGS sample shows a wide range in the ratio of [SIII]18.71um/[SIII]33.48um, but the average ratio of the ensemble indicates a typical interstellar electron density of 300-400cm^-3^ on ~23x15" scales and 500-600cm^-3^ using ~11x9" apertures, independent of whether the region probed is a star-forming nuclear, a star-forming extranuclear, or an active galactic nuclei (AGN) environment.
- ID:
- ivo://CDS.VizieR/J/ApJ/741/79
- Title:
- The Spitzer-SDSS-GALEX Spectroscopic Survey
- Short Name:
- J/ApJ/741/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer-SDSS-GALEX Spectroscopic Survey (SSGSS) provides a new sample of 101 star-forming galaxies at z<0.2 with unprecedented multi-wavelength coverage. New mid- to far-infrared spectroscopy from the Spitzer Space Telescope is added to a rich suite of previous imaging and spectroscopy, including ROSAT, Galaxy Evolution Explorer, Sloan Digital Sky Survey, Two Micron All Sky Survey, and Spitzer/SWIRE. Sample selection ensures an even coverage of the full range of normal galaxy properties, spanning two orders of magnitude in stellar mass, color, and dust attenuation. In this paper we present the SSGSS data set, describe the science drivers, and detail the sample selection, observations, data reduction, and quality assessment.
- ID:
- ivo://CDS.VizieR/J/ApJ/859/101
- Title:
- The supernovae Ia Pantheon sample
- Short Name:
- J/ApJ/859/101
- Date:
- 20 Jan 2022 07:41:10
- Publisher:
- CDS
- Description:
- We present optical light curves, redshifts, and classifications for 365 spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. We detail improvements to the PS1 SN photometry, astrometry, and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combine the subset of 279 PS1 SNe Ia (0.03<z<0.68) with useful distance estimates of SNe Ia from the Sloan Digital Sky Survey (SDSS), SNLS, and various low-z and Hubble Space Telescope samples to form the largest combined sample of SNe Ia, consisting of a total of 1048 SNe Ia in the range of 0.01<z<2.3, which we call the "Pantheon Sample". When combining Planck 2015 cosmic microwave background (CMB) measurements with the Pantheon SN sample, we find {Omega}_m_=0.307+/-0.012 and w=-1.026+/-0.041 for the wCDM model. When the SN and CMB constraints are combined with constraints from BAO and local H_0_ measurements, the analysis yields the most precise measurement of dark energy to date: w_0_=-1.007+/-0.089 and w_a_=-0.222+/-0.407 for the w_0_w_a_CDM model. Tension with a cosmological constant previously seen in an analysis of PS1 and low-z SNe has diminished after an increase of 2x in the statistics of the PS1 sample, improved calibration and photometry, and stricter light-curve quality cuts. We find that the systematic uncertainties in our measurements of dark energy are almost as large as the statistical uncertainties, primarily due to limitations of modeling the low-redshift sample. This must be addressed for future progress in using SNe Ia to measure dark energy.
- ID:
- ivo://CDS.VizieR/J/AJ/159/241
- Title:
- The TESS-Keck Survey. I. HD332231 Radial Velocities
- Short Name:
- J/AJ/159/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a Saturn-size exoplanet orbiting HD332231 (TOI1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD332231 an F8 dwarf star with a V-band magnitude of 8.56 was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow up observations of HD332231 with the Automated Planet Finder (APF), Keck I, and Spatial Observations Network Group (SONG) telescopes. The orbital period we infer from radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD332231b, a Saturn-size (0.867_-0.025_^+0.027^R_J_), sub-Saturn-mass (0.244{+/-}0.021M_J_) exoplanet on a 18.71day circular orbit. The low surface gravity of HD332231b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter-McLaughlin effect, an exciting prospect given the 0.14au orbital separation of HD332231b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14-16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5days.
- ID:
- ivo://CDS.VizieR/J/A+A/343/806
- Title:
- The trapezium system BD+00 1617
- Short Name:
- J/A+A/343/806
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Internal kinematics, spectroscopic binaries and galactic motion are investigated for the trapezium system BD+00 1617 (which lies at the heart of the young open cluster Bochum 2) by means on 73 high resolution Echelle+CCD spectra secured over the period 1994-98. Two of the three O-type member stars are found to be binaries on close and highly eccentric orbits of 6.8 and 11.0 day period. Tables 2 and 3, that are available only in electronic form, give the journal of the observations and the individual radial velocities.
- ID:
- ivo://CDS.VizieR/J/A+A/434/201
- Title:
- The 35um absorption line towards 1612MHz masers
- Short Name:
- J/A+A/434/201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 1612MHz hydroxyl maser in circumstellar envelopes has long been thought to be pumped by 34.6{mu}m photons. Only recently, the Infrared Space Observatory has made possible spectroscopic observations which enable the direct confirmation of this pumping mechanism in a few cases. To look for the presence of this pumping line, we have searched the Infrared Space Observatory Data Archive and found 178 spectra with data around 34.6{mu}m for 87 galactic 1612MHz masers.
