- ID:
- ivo://CDS.VizieR/J/A+A/401/657
- Title:
- Non-linear limb-darkening law for LTE models. II.
- Short Name:
- J/A+A/401/657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- As an extension of our previous investigations on stellar atmospheres (Claret, 2000, Cat. <J/A+A/363/1081>), the limb-darkening coefficients for the Geneva and Walraven photometric systems are presented for the first time using the ATLAS and PHOENIX models. They cover a wide range of values of logg, T_eff_, metallicities and microturbulent velocities. In addition to the traditional applications of limb-darkening coefficients, the present ones are now being used in the interpretation of phase shift of B and A-F type pulsating stars.
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- ID:
- ivo://CDS.VizieR/J/A+A/428/1001
- Title:
- Non-linear limb-darkening law for LTE models. III.
- Short Name:
- J/A+A/428/1001
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing our studies on stellar atmospheres (Claret, 2000, Cat. <J/A+A/363/1081>, 2003, Cat. <J/A+A/401/657>), we present in this paper the limb-darkening coefficients for the Sloan photometric system. The calculations cover a wide range of values of logg, T_eff_, metallicities and microturbulent velocities. The atmosphere models used are ATLAS and PHOENIX. In addition to the traditional applications of the limb-darkening coefficients, the present ones will be useful since the Sloan filters are now being used in the interpretation of light curves of extrasolar transiting planets, for example. The present calculations may also be useful, as a complement, for the Kepler mission, dedicated to the search for terrestrial planets.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1975
- Title:
- Normal spiral galaxies optical and UV photometry
- Short Name:
- J/AJ/140/1975
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the UV-optical colors of a well-defined set of optically selected pre-merger interacting galaxy pairs with those of normal spirals. The shorter wavelength colors show a larger dispersion for the interacting galaxies than for the spirals. This result can best be explained by higher star formation rates on average in the interacting galaxies, combined with higher extinctions on average. This is consistent with earlier studies which found that the star formation in interacting galaxies tends to be more centrally concentrated than in normal spirals, perhaps due to gas being driven into the center by the interaction. As noted in earlier studies, there is a large variation from galaxy to galaxy in the implied star formation rates of the interacting galaxies, with some galaxies having enhanced rates but others being fairly quiescent.
- ID:
- ivo://CDS.VizieR/J/BaltA/18/141
- Title:
- North America/Pelican red clump giants ugriJHK
- Short Name:
- J/BaltA/18/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A possibility of applying 2MASS J, H, Ks, IPHAS r, i and Mega-Cam u, g photometry of red giants for determining distances to dark clouds is investigated. Red clump giants with a small admixture of G5-K1 and M2-M3 stars of the giant branch can be isolated and used in determining distances to separate clouds or spiral arms. Interstellar extinctions of background red giants can be also used for mapping dust surface density in the cloud.
- ID:
- ivo://CDS.VizieR/J/PASP/109/441
- Title:
- Northern Cataclysmic Variables
- Short Name:
- J/PASP/109/441
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An average of 30 B,V secondary standards per field have been established for 76 variable stars. These are mostly cataclysmic variables of various subclasses but also include a variety of other kinds of variable stars. The standards are within a few arc minutes of the variable and are therefore well suited for CCD photometry. The standards have brightnesses of V~12-17 and have a typical accuracy per standard of +/-0.01mag. (c) Astronomical Society of the Pacific
- ID:
- ivo://CDS.VizieR/J/PASP/107/324
- Title:
- Northern CV secondary photometric standards
- Short Name:
- J/PASP/107/324
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An average of 11 B, V secondary standards per field have been established for 58 cataclysmic variable stars, most of which are nova-like variables. The standards are within a few arcminutes of the variable and are therefore well-suited for CCD photometry. The standards have brightness of V~12-17 and have a typical accuracy per standard of +0.02mag.
- ID:
- ivo://CDS.VizieR/J/ApJS/117/319
- Title:
- Northern RASS X-ray sources catalog
- Short Name:
- J/ApJS/117/319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of optical identifications of a representative sample of northern ({delta})>-9{deg}) ROSAT All-Sky Survey (RASS) sources. A full identification has been carried out for a count-rate- and area-limited complete RASS subsample comprising 674 sources. All sources are within six study areas outside the galactic plane (|b|>19.6{deg}), one area being near the north Galactic pole and one near the north ecliptic pole.
- ID:
- ivo://CDS.VizieR/J/MNRAS/457/110
- Title:
- Northern XMM-XXL field AGN catalog
- Short Name:
- J/MNRAS/457/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a survey of X-ray-selected active galactic nuclei (AGNs) with optical spectroscopic follow-up in a ~18deg^2^ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by XMM-Newton above a limiting flux of F_0.5-10keV_>10^-15^erg/cm2/s was matched to optical (Sloan Digital Sky Survey, SDSS) and infrared (IR; WISE) counterparts. We followed up 3042 sources brighter than r=22.5mag with the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) spectrograph. The spectra yielded a reliable redshift measurement for 2578 AGNs in the redshift range z=0.02-5.0, with 0.5-2keV luminosities ranging from 10^39^-10^46^erg/s. This is currently the largest published spectroscopic sample of X-ray-selected AGNs in a contiguous area. The BOSS spectra of AGN candidates show a distribution of optical line widths which is clearly bimodal, allowing an efficient separation between broad- and narrow-emission line AGNs. The former dominate our sample (70 per cent) due to the relatively bright X-ray flux limit and the optical BOSS magnitude limit. We classify the narrow-emission line objects (22 per cent of the full sample) using standard optical emission line diagnostics: the majority have line ratios indicating the dominant source of ionization is the AGN. A small number (8 per cent of the full sample) exhibit the typical narrow line ratios of star-forming galaxies, or only have absorption lines in their spectra. We term the latter two classes 'elusive' AGN, which would not be easy to identify correctly without their X-ray emission. We also compare X-ray (XMM-Newton), optical colour (SDSS) and and IR (WISE) AGN selections in this field. X-ray observations reveal, by far, the largest number of AGN. The overlap between the selections, which is a strong function of the imaging depth in a given band, is also remarkably small. We show using spectral stacking that a large fraction of the X-ray AGNs would not be selectable via optical or IR colours due to host galaxy contamination. A substantial fraction of AGN may therefore be missed by these longer wavelength selection methods.
- ID:
- ivo://CDS.VizieR/J/A+A/300/323
- Title:
- NOT GL survey of multiply imaged quasars
- Short Name:
- J/A+A/300/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A gravitational lens (GL)-search program, initiated in 1990 at the Nordic Optcal Telescope (NOT), has revealed several possible GL-candidates among a sample of 168 quasars (QSOs), chosen from three lists compiled by C. Hazard, D. Reimers and J. Surdej, respectively. Some of these candidates, selected for having close companions (within 5 arcseconds), were imaged in several filters and their colours compared. Low dispersion spectra of the most promising candidates were also obtained at the NOT and ESO New Technology Telescope (NTT). None of these has proved to be strong candidates of gravitational lensing effects. We present this new sample of QSOs and combine it with previously published optical QSO samples in a statistical analysis to yield constraints on flat cosmologies and galaxy velocity dispersions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/3402
- Title:
- Nova Cep 2013 (V809 Cep) UBVRI light curves
- Short Name:
- J/MNRAS/440/3402
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVR_C_I_C_ photometry and low-, medium- and high-resolution echelle fluxed spectroscopy is presented and discussed for three faint, heavily reddened novae of the Feii-type which erupted in 2013. V1830 Nova Aql 2013 reached a peak V=15.2mag on 2013 Oct 30.3 UT and suffered from a huge E(B-V)~2.6mag reddening. After a rapid decline, when the nova was {Delta}V=1.7mag below maximum, it entered a flat plateau where it remained for a month until solar conjunction prevented further observations. Similar values were observed for V556 Nova Ser 2013, that peaked near R_C_~12.3 around 2013 Nov 25 and soon went lost in the glare of sunset sky. A lot more observations were obtained for V809 Nova Cep 2013, that peaked at V=11.18 on 2013 Feb 3.6. The reddening is E(B-V)~1.7 and the nova is located within or immediately behind the spiral Outer Arm, at a distance of ~6.5kpc as constrained by the velocity of interstellar atomic lines and the rate of decline from maximum. While passing at t_3_, the nova begun to form a thick dust layer that caused a peak extinction of {Delta}V>5mag, and took 125d to completely dissolve. The dust extinction turned from neutral to selective around 6000{AA}. Monitoring the time evolution of the integrated flux of emission lines allowed us to constrain the region of dust formation in the ejecta to be above the region of formation of OI 7774{AA} and below that of CaII triplet. Along the decline from maximum and before the dust obscuration, the emission line profiles of Nova Cep 2013 developed a narrow component (FWHM=210km/s) superimposed on to the much larger normal profile, making it a member of the so-far exclusive but growing club of novae displaying this peculiar feature. Constrains based on the optical thickness of the innermost part of the ejecta and on the radiated flux, place the origin of the narrow feature within highly structured internal ejecta and well away from the central binary.
