- ID:
- ivo://CDS.VizieR/J/MNRAS/328/805
- Title:
- The 2dF QSO Redshift Survey. VIII
- Short Name:
- J/MNRAS/328/805
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the highest signal-to-noise ratio spectra from the 2dF QSO Redshift Survey (2QZ) 10k release (Cat. <VII/223>) and identify over 100 new low-ionization heavy-element absorbers: damped Lyman-{alpha} (DLA) candidates suitable for higher-resolution follow-up observations. These absorption systems map the spatial distribution of high-z metals in exactly the same volumes as the foreground 2QZ QSOs themselves sample and hence the 2QZ gives us the unique opportunity to compare directly the two tracers of large-scale structure. We examine the cross-correlation of the two populations to see how they are relatively clustered, and, by considering the colour of the QSOs, detect a small amount of dust in these metal systems.
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Search Results
- ID:
- ivo://CDS.VizieR/VII/223
- Title:
- The 2dF QSO Redshift Survey. V. The 10k catalogue
- Short Name:
- VII/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2dF QSO Redshift Survey (2QZ) 10k catalogue is the first release of the 2QZ, containing over 10000 QSOs. There are a total of 20590 sources listed, for which spectra have been obtained using the 2-degree field facility at the Anglo-Australian Observatory. Current data covers an effective area of 289.6deg^2^ for QSO candidates with magnitudes 18.25<b_J_<20.85. The file 2qz_10k.dat contains the names, positions, magnitudes, spectroscopic identifications and redshifts for each of the sources.
- ID:
- ivo://CDS.VizieR/J/AJ/135/1249
- Title:
- The early spectra of eta Carinae
- Short Name:
- J/AJ/135/1249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The observed behavior of {eta} Car from 1860 to 1940 has not been considered in most recent accounts, nor has it been explained in any quantitative model. We have used modern digital processing techniques to examine Harvard objective-prism spectra made from 1892 to 1941. Relatively high excitation HeI{lambda}4471 and [FeIII]4658 emission, conspicuous today, were weak and perhaps absent throughout those years. Feast et al. (2001MNRAS.322..741F) noted this qualitative fact for other pre-1920 spectra, but we quantify it and extend it to a time only three years before Gaviola (1953ApJ...118..234G)'s first observations of the high-excitation features. Evidently the supply of helium-ionizing photons ({lambda}<504{AA}) grew rapidly between 1941 and 1944. The apparent scarcity of such far-UV radiation before 1944 is difficult to explain in models that employ a hot massive secondary star, because no feasible dense wind or obscuration by dust would have hidden the photoionization caused by the proposed companion during most of its orbital period. We also discuss the qualitative near-constancy of the spectrum from 1900 to 1940, and {eta} Car's photometric and spectroscopic transition between 1940 and 1953.
- ID:
- ivo://CDS.VizieR/J/A+A/523/A57
- Title:
- The Earth as a transiting planet
- Short Name:
- J/A+A/523/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An important goal within the quest for detecting an Earth-like extrasolar planet, will be to identify atmospheric gaseous bio-signatures. Aims. Observations of the light transmitted through the Earth's atmosphere, as for an extrasolar planet, will be the first important step for future comparisons. We have completed observations of the Earth during a lunar eclipse, a unique situation similar to that of a transiting planet. We aim at showing what species could be detected in its atmosphere at optical wavelengths, where a lot of photons are available in the masked stellar light. We present observations of the 2008 August 16 Moon eclipse performed with the SOPHIE spectrograph at the Observatoire de Haute- Provence (France). Locating the spectrograph's fibers in the penumbra of the eclipse, the Moon irradiance is then a mix of direct, unabsorbed Sun light and solar light that has passed through the Earth's atmosphere. This mixture essentially reproduces what is recorded during the transit of an extrasolar planet. We report here the clear detection of several Earth atmospheric compounds in the transmission spectra, such as ozone, molecular oxygen, and neutral sodium as well as molecular nitrogen and oxygen through the Rayleigh signature. Moreover, we present a method that allows us to derive the thickness of the atmosphere versus the wavelength for penumbra eclipse observations. We quantitatively evaluate the altitude at which the atmosphere becomes transparent for important species like molecular oxygen and ozone, two species thought to be tightly linked to the presence of life. The molecular detections presented here are an encouraging first attempt, necessary to better prepare for the future of extremely-large telescopes and transiting Earth-like planets. Instruments like SOPHIE will be mandatory when characterizing the atmospheres of transiting Earth-like planets from the ground and searching for bio-marker signatures.
- ID:
- ivo://CDS.VizieR/J/ApJ/889/49
- Title:
- The ELM Survey. VIII. Final double WD binaries
- Short Name:
- J/ApJ/889/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the final sample of 98 detached double white dwarf (WD) binaries found in the Extremely Low Mass (ELM) Survey, a spectroscopic survey targeting <0.3M_{sun}_ He-core WDs completed in the Sloan Digital Sky Survey footprint. Over the course of the survey we observed ancillary low-mass WD candidates like GD 278, which we show is a P=0.19d double WD binary, as well as candidates that turn out to be field blue straggler/subdwarf A-type stars with luminosities too high to be WDs given their Gaia parallaxes. Here, we define a clean sample of ELM WDs that is complete within our target selection and magnitude range 15<g_0_<20mag. The measurements are consistent with 100% of ELM WDs being 0.0089<P<1.5d double WD binaries, 35% of which belong to the Galactic halo. We infer that these are mostly He+CO WD binaries given the measurement constraints. The merger rate of the observed He+CO WD binaries exceeds the formation rate of stable mass-transfer AM CVn binaries by a factor of 25, and so the majority of He+CO WD binaries must experience unstable mass transfer and merge. The systems with the shortest periods, such as J0651+2844, are signature LISA verification binaries that can be studied with gravitational waves and light.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/5
- Title:
- The ELQS in the PS1 footprint (PS-ELQS)
- Short Name:
- J/ApJS/243/5
- Date:
- 08 Mar 2022 13:10:17
- Publisher:
- CDS
- Description:
- We present the results of the Extremely Luminous Quasar Survey in the 3{pi} survey of the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS; PS1). This effort applies the successful quasar selection strategy of the Extremely Luminous Survey in the Sloan Digital Sky Survey footprint (~12000deg^2^) to a much larger area (~21486deg^2^). This spectroscopic survey targets the most luminous quasars (M_1450_<=-26.5; m_i_<=18.5) at intermediate redshifts (z>=2.8). Candidates are selected based on a near-infrared JKW2 color cut using WISE AllWISE and 2MASS photometry to mainly reject stellar contaminants. Photometric redshifts (z_reg_) and star-quasar classifications for each candidate are calculated from near-infrared and optical photometry using the supervised machine learning technique random forests. We select 806 quasar candidates at z_reg_>=2.8 from a parent sample of 74318 sources. After exclusion of known sources and rejection of candidates with unreliable photometry, we have taken optical identification spectra for 290 of our 334 good PS-ELQS candidates. We report the discovery of 190 new z>=2.8 quasars and an additional 28 quasars at lower redshifts. A total of 44 good PS-ELQS candidates remain unobserved. Including all known quasars at z>=2.8, our quasar selection method has a selection efficiency of at least 77%. At lower declinations, -30<=DEC<=0, we approximately treble the known population of extremely luminous quasars. We provide the PS-ELQS quasar catalog with a total of 592 luminous quasars (m_i_<=18.5, z>=2.8). This unique sample will not only be able to provide constraints on the volume density and quasar clustering of extremely luminous quasars, but also offers valuable targets for studies of the intergalactic medium.
- ID:
- ivo://CDS.VizieR/J/ApJS/215/22
- Title:
- The Extended Virgo Cluster Catalog (EVCC)
- Short Name:
- J/ApJS/215/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog of galaxies in the wider region of the Virgo cluster, based on the Sloan Digital Sky Survey (SDSS) Data Release 7. The Extended Virgo Cluster Catalog (EVCC) covers an area of 725deg^2^ or 60.1Mpc^2^. It is 5.2 times larger than the footprint of the classical Virgo Cluster Catalog (VCC) and reaches out to 3.5 times the virial radius of the Virgo cluster. We selected 1324 spectroscopically targeted galaxies with radial velocities less than 3000km/s. In addition, 265 galaxies that have been overlooked in the SDSS spectroscopic survey but have available redshifts in the NASA Extragalactic Database are also included. Our selection process secured a total of 1589 galaxies, 676 of which are not included in the VCC. The certain and possible cluster members are defined by means of redshift comparison with a cluster infall model. We employed two independent and complementary galaxy classification schemes: the traditional morphological classification based on the visual inspection of optical images and a characterization of galaxies from their spectroscopic features. SDSS u, g, r, i, and z passband photometry of all EVCC galaxies was performed using Source Extractor. We compare the EVCC galaxies with the VCC in terms of morphology, spatial distribution, and luminosity function. The EVCC defines a comprehensive galaxy sample covering a wider range in galaxy density that is significantly different from the inner region of the Virgo cluster. It will be the foundation for forthcoming galaxy evolution studies in the extended Virgo cluster region, complementing ongoing and planned Virgo cluster surveys at various wavelengths.
- ID:
- ivo://CDS.VizieR/J/A+A/418/885
- Title:
- The FORS Deep Field Spectroscopic Survey
- Short Name:
- J/A+A/418/885
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue and atlas of low-resolution spectra of a sample of 341 objects with reliable redshifts in the FORS Deep Field (FDF). The sample contains 42 stars, 8 QSOs, and 291 galaxies up to z=5.98 objects are at z>2. For z>1 most objects were selected using photometric redshifts. The limiting I magnitude has been I=24.5 for 2<z<4. All spectra were obtained using the FORS instruments at the ESO VLT and cover the wavelength range 3300-10000{AA}. The grism 150I with a 1" slit width was used, resulting in a spectral resolution element of our spectra of 18-24{AA}, depending on the light distribution in the slit. Most objects were observed several times. Typical exposure times were about 10h for our z>2 objects. The individual spectra were S/N-optimised co-added. The final spectra were flux calibrated, smoothed to the resolution element, and corrected for atmospheric extinction. Moreover, the spectra were corrected for the atmospheric A and B bands. Redshifts and rough object types were derived by cross-correlation of the galaxy spectra with six template spectra, which had been created from high-quality FDF spectroscopic data by an iterative procedure.
2799. The FUSE Observation Log
- ID:
- ivo://CDS.VizieR/VI/129
- Title:
- The FUSE Observation Log
- Short Name:
- VI/129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Funded by NASA as part of its Origins program, FUSE was developed in collaboration with the space agencies of Canada and France, and is being operated for NASA by the Johns Hopkins University. FUSE was launched into orbit aboard a Delta II rocket on June 24, 1999 for at least three years of operations. FUSE (Far Ultraviolet Spectroscopic Explorer) provides spectra in the far ultraviolet portion of the electromagnetic spectrum (range 905-1180 Angstroems, or 90.5-118nm) with a high resolution of about 20000 (one point each 5pm).
- ID:
- ivo://CDS.VizieR/J/A+A/566/A98
- Title:
- The Gaia Benchmark Stars - Library
- Short Name:
- J/A+A/566/A98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An increasing number of high-resolution stellar spectra is available today thanks to many past and ongoing spectroscopic surveys. Consequently, numerous methods have been developed to perform an automatic spectral analysis on a massive amount of data. When reviewing published results, biases arise and they need to be addressed and minimized. We are providing a homogeneous library with a common set of calibration stars (known as the Gaia FGK benchmark stars) that will allow us to assess stellar analysis methods and calibrate spectroscopic surveys. High-resolution and signal-to-noise spectra were compiled from different instruments. We developed an automatic process to homogenize the observed data and assess the quality of the resulting library.
