- ID:
- ivo://CDS.VizieR/J/A+A/434/1201
- Title:
- ESO VLTI Calibrators Program
- Short Name:
- J/A+A/434/1201
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ESO Very Large Telescope Interferometer (VLTI) is one of the leading interferometric facilities. It is equiped with several 8.2 and 1.8m telescopes, a large number of baselines up to 200m, and with several subsystems designed to enable high quality measurements and to improve significantly the limits of sensitivities currently available to long-baseline interferometry. For this, a large number of observations of potential calibrators have been obtained during the commissioning phase of the VLTI. These data are publicly available.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/507/85
- Title:
- ESO/VLT 3rd year type Ia supernova data set
- Short Name:
- J/A+A/507/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 139 spectra of 124 Type Ia supernovae (SNe Ia) that were observed at the ESO/VLT during the first three years of the Canada-France-Hawai Telescope (CFHT) supernova legacy survey (SNLS). This homogeneous data set is used to test for redshift evolution of SN Ia spectra, and will be used in the SNLS 3rd year cosmological analyses. Spectra have been reduced and extracted with a dedicated pipeline that uses photometric information from deep CFHT legacy survey (CFHT-LS) reference images to trace, at sub-pixel accuracy, the position of the supernova on the spectrogram as a function of wavelength. It also separates the supernova and its host light in ~60% of cases. The identification of the supernova candidates is performed using a spectrophotometric SN Ia model.
- ID:
- ivo://CDS.VizieR/J/MNRAS/475/1960
- Title:
- ESPaDOnS spectropolarimeter obs. of M dwarfs
- Short Name:
- J/MNRAS/475/1960
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Present and future high-precision radial-velocity spectrometers dedicated to the discovery of low-mass planets orbiting low-mass dwarfs need to focus on the best selected stars to make an efficient use of telescope time. In the framework of the preparation of the SPIRou Input Catalogue (SPIC), the CoolSnap program aims at screening M dwarfs in the solar neighbourhood against binarity, rapid rotation, activity, etc. To optimize the selection, this paper describes the methods used to compute effective temperature, metallicity, projected rotation velocity of a large sample of 440 M dwarfs observed in the visible with the high-resolution spectropolarimeter Echelle SpectroPolArimetric Device for the ObservatioN of Stars (ESPaDOnS) at Canada-France-Hawaii Telescope. It also summarizes known and newly discovered spectroscopic binaries, and stars known to belong to visual multiple systems. A calibration of the projected rotation velocity versus measured line widths for M dwarfs observed by the ESPaDOnS spectropolarimeter is derived, and the resulting values are compared to equatorial rotation velocities deduced from rotation periods and radii. A comparison of the derived effective temperatures and metallicities with literature values is also conducted. Finally, the radial-velocity uncertainty of each star in the sample is estimated, to narrow down the selection of stars to be included into the SPIC.
- ID:
- ivo://CDS.VizieR/J/A+A/629/A80
- Title:
- ESPRESSO blind RV exoplanet survey catalog
- Short Name:
- J/A+A/629/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the main scientific drivers for ESPRESSO, Echelle SPectrograph, is the detection and characterization of Earth-class exoplanets. With this goal in mind, the ESPRESSO guaranteed time observations (GTO) Catalog identifies the best target stars for a blind search for the radial velocity (RV) signals caused by Earth-class exoplanets. Using the most complete stellar catalogs available, we screened for the most suitable G, K, and M dwarf stars for the detection of Earth-class exoplanets with ESPRESSO. For most of the stars, we then gathered high-resolution spectra from new observations or from archival data. We used these spectra to spectroscopically investigate the existence of any stellar binaries, both bound or background stars. We derived the activity level using chromospheric activity indexes using log (R'_HK_), as well as the projected rotational velocity vsini. For the cases where planet companions are already known, we also looked at the possibility that additional planets may exist in the host's habitable zone using dynamical arguments. We estimated the spectroscopic contamination level, vsini, activity, stellar parameters and chemical abundances for 249 of the most promising targets. Using these data, we selected 45 stars that match our criteria for detectability of a planet like Earth. The stars presented and discussed in this paper constitute the ESPRESSO GTO catalog for the RV blind search for Earth-class planets. They can also be used for any other work requiring a detailed spectroscopic characterization of stars in the solar neighborhood.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A129
- Title:
- ESPRESSO radial velocities of HE0107-5240
- Short Name:
- J/A+A/633/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The vast majority of the known stars of ultra low metallicity ([Fe/H]<-4.5) are known to be enhanced in carbon, and belong to the 'low-carbon band' (A(C)=log(C/H)+12~7.6). It is generally, although not universally, accepted that this peculiar chemical composition reflects the chemical composition of the gas cloud out of which these stars were formed. The first ultra-metal-poor star discovered, HE 0107-5240, is also enhanced in carbon and belongs to the 'low-carbon band'. It has recently been claimed to be a long-period binary, based on radial velocity measurements. It has also been claimed that this binarity may explain its peculiar composition as being due to mass transfer to a former AGB companion. Theoretically, low-mass ratios in binary systems are much more favoured amongst Pop III stars than they are amongst solar-metallicity stars. Any constraint on the mass ratio of a system of such low metallicity would shed light on the star formation mechanisms in this metallicity regime. We acquired one high precision spectrum with ESPRESSO in order to check the reality of the radial velocity variations. In addition we analysed all the spectra of this star in the ESO archive obtained with UVES to have a set of homogenously measured radial velocities. The radial velocities were measured using cross correlation against a synthetic spectrum template. Due to the weakness of metallic lines in this star, the signal comes only from the CH molecular lines of the G-band. The measurement obtained in 2018 from an ESPRESSO spectrum demonstrates unambiguously that the radial velocity of HE 0107-5240 has increased from 2001 to 2018. Closer inspection of the measurements based on UVES spectra in the interval 2001-2006 show that there is a 96% probability that the radial velocity correlates with time, hence the radial velocity variations can already be suspected from the UVES spectra alone. We confirm the earlier claims of radial velocity variations in HE 0107-5240. The simplest explanation of such variations is that the star is indeed in a binary system with a long period. The nature of the companion is unconstrained and we consider it is equally probable that it is an unevolved companion or a white dwarf. Continued monitoring of the radial velocities of this star is strongly encouraged.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3731
- Title:
- ESSENCE high-redshift supernova
- Short Name:
- J/AJ/137/3731
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic observations from the ESSENCE high-redshift supernova (SN) survey during its first four years of operation. This sample includes spectra of all SNe Ia whose light curves were presented by Miknaitis et al. (2007, Cat. J/ApJ/666/674) and used in the cosmological analyses of Davis et al. (2007ApJ...666..716D) and Wood-Vasey et al. (2007ApJ...666..694W). The sample represents 273hr of spectroscopic observations with 6.5-10m class telescopes of objects detected and selected for spectroscopy by the ESSENCE team. We present 184 spectra of 156 objects. Combining this sample with that of Matheson et al. (2008, Cat. J/AJ/135/1598), we have a total sample of 329 spectra of 274 objects. From this, we are able to spectroscopically classify 118 Type Ia SNe.
5707. ESSENCE supernova survey
- ID:
- ivo://CDS.VizieR/J/ApJ/666/674
- Title:
- ESSENCE supernova survey
- Short Name:
- J/ApJ/666/674
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the dark energy equation-of-state parameter, w=P/({rho}c^2^). We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to w for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z~0.5+/-0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in nearly real time.
- ID:
- ivo://CDS.VizieR/J/ApJS/224/3
- Title:
- ESSENCE 6yr spectroscopic follow-up
- Short Name:
- J/ApJS/224/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Equation of State: Supernovae trace Cosmic Expansion (ESSENCE) survey discovered 213 Type Ia supernovae at redshifts 0.1<z<0.81 between 2002 and 2008. We present their R- and I-band photometry, measured from images obtained using the MOSAIC II camera at the CTIO Blanco, along with rapid-response spectroscopy for each object. We use our spectroscopic follow-up observations to determine an accurate, quantitative classification, and precise redshift. Through an extensive calibration program we have improved the precision of the CTIO Blanco natural photometric system. We use several empirical metrics to measure our internal photometric consistency and our absolute calibration of the survey. We assess the effect of various potential sources of systematic bias on our measured fluxes, and estimate the dominant term in the systematic error budget from the photometric calibration on our absolute fluxes is ~1%.
- ID:
- ivo://CDS.VizieR/J/A+A/628/A104
- Title:
- [ESS2003] Q2343-BX610 reduced PdBI spectra
- Short Name:
- J/A+A/628/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Plateau De Bure Interferometer to observe multiple CO and neutral carbon transitions in a z=2.2 main sequence disk galaxy, BX610. Our observation of CO(7-6), CO(4-3) and both far infrared [CI] lines complements previous observations of H-alpha and low-J CO, and reveal a galaxy that is vigorously forming stars with UV fields, (Log(G/G_0_)<3.25), less extreme than local ULIRGs or most starbursting submillimeter galaxies in the early universe. Our observations allow new independent estimates of the cold gas mass which indicate M_gas_~2x10^11^M_{sun}_, and suggest a modestly larger alpha_CO value of ~8.2. The corresponding gas depletion timescale is ~1.5Gyr. In addition to gas of modest density (Log(n[cm^-3^])<3) heated by star formation, BX610 shows evidence for a significant second gas component responsible for the strong high-J CO emission. This second component might either be a high density molecular gas component heated by star formation in a typical photodissociation region, or it could be molecular gas excited by low velocity C shocks. The CO(7-6) to far infrared luminosity ratio we observe is significantly higher than typical star forming galaxies and suggests that CO(7-6) is not a reliable star formation tracer in this galaxy.
- ID:
- ivo://CDS.VizieR/V/14
- Title:
- Estimated astrophysical parameters from uvby
- Short Name:
- V/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observed values of the Stroemgren uvby colors were collected from the literature. A computer program calculated the reddening for each star. This value was used to compute the unreddened value of (b-v), c1, and m1. These were then used to compute [c(1)], [m(1)], and [u-b] for the star. Except for the H beta index, the observed quantities are not included.