- ID:
- ivo://CDS.VizieR/J/ApJ/860/83
- Title:
- 22 extreme [OIII] emitters at z~0.5 from SDSS-DR14
- Short Name:
- J/ApJ/860/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have found a sample of extreme emission-line galaxies (EELGs) with strong [OIII]{lambda}5007 emission at z~0.5. Using broadband photometric selection and requiring small uncertainties in photometry, we searched the 14th Data Release of the Sloan Digital Sky Survey (SDSS) and found 2658 candidates with strong i-band excess (i-z<=r-i-0.7). We further obtained 649 SDSS spectra of these objects, and visually identified 22 [OIII] emitters lying at 0.40<z<0.63. Having constructed their ultraviolet-infrared spectral energy distributions, we found that they have fairly blue r-W2 and red W1-W4 colors, indicative of strong, warm dust emission. Their rest-frame [OIII]{lambda}5007 equivalent widths are mostly 200-600{AA}, and their high [OIII]{lambda}5007/H{beta} ratios put them at the boundary of star-forming galaxies and active galactic nuclei on line ratio classification diagrams. The typical E(B-V) and electron temperature of [OIII] emitters are ~0.1-0.3mag and ~104K, respectively. The lowest metallicity of our [OIII] emitters with S/N[OIII]{lambda}4363>3 is 12+log(O/H)=7.98_-0.02_^+0.12^, with a median value of 8.24_-0.04_^+0.05^. Our [OIII] emitters exhibit remarkably high line luminosity-18/22 have L[OIII]{lambda}5007>5x10^42^erg/s and 5/22 have L[OIII]{lambda}5007>10^43^erg/s. Their estimated volume number density at z~0.5 is ~2x10^-8^Mpc^-3^, with L[OIII]{lambda}5007 down to ~3x10^42^erg/s. The cumulative number distribution of EELGs across different redshifts is indicative of a strong redshift evolution at the bright end of the [OIII] luminosity function.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/119/37
- Title:
- EZ CMa UBV & VBLUW photometry
- Short Name:
- J/A+AS/119/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyse photometric and spectroscopic observations of the WN5 star EZ Canis Majoris obtained over a period of 7 years. We discuss the changing light curve, the shift in phase of the maxima and point to flare type variability seen in one night. Small amplitude variations are reported in another night. We have investigated the change of the average visual magnitude over a time span of 18 years and found a tentative cyclic variation with a time scale of 2425d (6.6yr) with a range of ~0.07mag. This, of course, should be verified. If true, a precession phenomenon may offer an explanation. The trend of the maximum light amplitude of the 3.766d cycle is also investigated and it shows a saw-tooth character with a timescale of ~400d. A possible relation with the magnetic activity of the star is discussed. We conclude that the line emission variability can be caused by both a single star model with an ever-changing wind and a binary (WN+NS) model.
- ID:
- ivo://CDS.VizieR/J/A+AS/106/451
- Title:
- Face-on disk galaxies photometry. I.
- Short Name:
- J/A+AS/106/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/642/A225
- Title:
- Faculae-Spot dominance & rotation periods
- Short Name:
- J/A+A/642/A225
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar rotation periods can be determined by observing brightness variations caused by active magnetic regions transiting visible stellar disk as the star rotates. The successful stellar photometric surveys stemming from the Kepler and TESS observations led to the determination of rotation periods in tens of thousands of young and active stars. However, there is still a lack of information about rotation periods of older and less active stars, like the Sun. The irregular temporal profiles of light curves caused by the decay times of active regions, which are comparable to or even shorter than stellar rotation periods, combine with the random emergence of active regions to make period determination for such stars very difficult. We tested the performance of the new method for the determination of stellar rotation periods against stars with previously determined rotation periods. The method is based on calculating the gradient of the power spectrum (GPS) and identifying the position of the inflection point (i.e. point with the highest gradient). The GPS method is specifically aimed at determining rotation periods of low-activity stars like the Sun. We applied the GPS method to Sun-like stars observed by the Kepler telescope. We separately considered two stellar samples: one with near-solar rotation periods (24-27.4d) and broad range of effective temperatures (5000-6000K), another with near-solar effective temperatures (5700-5900K) and broad range of rotation periods (15-40d). We show that the GPS method returns precise values of stellar rotation periods. Furthermore, it allows us to constrain the ratio between facular and spot areas of active regions at the moment of their emergence. We show that relative facular area decreases with stellar rotation rate. Our results suggest that the GPS method can be successfully applied to retrieve periods of stars with both regular and non-regular light curves.
- ID:
- ivo://CDS.VizieR/J/ApJS/153/119
- Title:
- Faint blue objects at high galactic latitude
- Short Name:
- J/ApJS/153/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The US (UV-excess Starlike) survey has cataloged 3987 objects in 7 high Galactic latitude fields according to their optical colors, magnitudes, and morphologies using photographic techniques. This paper analyzes the effectiveness of the survey at producing finding lists for complete samples of hot stars and quasars that exhibit blue and/or ultraviolet excess (B-UVX) relative to the colors of halo F and G subdwarf stars. A table of 599 spectroscopic identifications summarizes the spectroscopic coverage of the US objects that has been accomplished to date.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/2414
- Title:
- Faint cataclysmic variables from SDSS
- Short Name:
- J/MNRAS/421/2414
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-speed photometric observations of 20 faint cataclysmic variables (CVs) selected from the Sloan Digital Sky Survey (SDSS) and Catalina catalogues. Measurements are given of 15 new directly measured orbital periods, including four eclipsing dwarf novae (SDSS 0904+03, CSS 0826-00, CSS 1404-10 and CSS 1626-12), two new polars (CSS 0810+00 and CSS 1503-22) and two dwarf novae with superhumps in quiescence (CSS 0322+02 and CSS 0826-00). Whilst most of the dwarf novae presented here have periods below 2h, SDSS 0805+07 and SSS 0617-36 have relatively long orbital periods of 5.489 and 3.440h, respectively. The double-humped orbital modulations observed in SSS 0221-26, CSS 0345-01, CSS 1300+11 and CSS 1443-17 are typical of low-mass transfer rate dwarf novae. The white dwarf primary of SDSS 0919+08 is confirmed to have non-radial oscillations, and quasi-periodic oscillations were observed in the short-period dwarf nova CSS 1028-08 during outburst. We further report the detection of a new nova-like variable (SDSS 1519+06). The frequency distribution of orbital periods of CVs in the Catalina Real-time Transient Survey (CRTS) has a high peak near ~80min orbital period, independently confirming that found by Gansicke et al. (2009MNRAS.397.2170G) from SDSS sources. We also observe a marked correlation between the median in the orbital period distribution and the outburst class, in the sense that dwarf novae with a single observed outburst (over the 5-year baseline of the CRTS coverage) occur predominantly at shortest orbital period.
- ID:
- ivo://CDS.VizieR/J/MNRAS/443/3174
- Title:
- 72 faint CV candidates in CRTS
- Short Name:
- J/MNRAS/443/3174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Over six years of operation, the Catalina Real-time Transient Survey (CRTS) has identified 1043 cataclysmic variable (CV) candidates - the largest sample of CVs from a single survey to date. Here, we provide spectroscopic identification of 85 systems fainter than g>=19, including three AM Canum Venaticorum binaries, one helium-enriched CV, one polar and one new eclipsing CV. We analyse the outburst properties of the full sample and show that it contains a large fraction of low-accretion-rate CVs with long outburst recurrence times. We argue that most of the high-accretion-rate dwarf novae in the survey footprint have already been found and that future CRTS discoveries will be mostly low-accretion-rate systems. We find that CVs with white-dwarf-dominated spectra have significantly fewer outbursts in their CRTS light curves compared to disc-dominated CVs, reflecting the difference in their accretion rates. Comparing the CRTS sample to other samples of CVs, we estimate the overall external completeness to be 23.6 per cent, but show that as much as 56 per cent of CVs have variability amplitudes that are too small to be selected using the transient selection criteria employed by current ground-based surveys. The full table of CRTS CVs, including their outburst and spectroscopic properties examined in this paper, is provided in the online materials.
- ID:
- ivo://CDS.VizieR/J/AJ/130/1324
- Title:
- Faint emission-line galaxies at z<=1.6
- Short Name:
- J/AJ/130/1324
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) Grism Parallel Survey, a large program obtaining deep, slitless ACS grism (R~100) spectroscopy of high-latitude HST parallel fields. We identify 601 compact emission-line galaxies at z<=1.6, reaching emission lines to a flux limit of >~5x10^-18^ergs/cm^2^/s (3{sigma}). We determine redshifts by cross-correlation of the target spectra with template spectra, followed by visual inspection. We measure star formation rates from the observed [OII]{lambda}3727, [OIII]{lambda}5007, and H{alpha} line fluxes.
- ID:
- ivo://CDS.VizieR/J/MNRAS/380/281
- Title:
- Faint galactic satellites spectroscopic survey
- Short Name:
- J/MNRAS/380/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a spectroscopic survey of the recently discovered faint Milky Way satellites Bootes, Ursa Major I, Ursa Major II and Willman 1 (Wil1). Using the DEep Imaging Multi-Object Spectrograph mounted on the Keck II telescope, we have obtained samples that contain from ~15 to ~85 probable members of these satellites for which we derive radial velocities precise to a few km/s down to i~21-22. About half of these stars are observed with a high enough signal-to-noise ratio to estimate their metallicity to within +/-0.2dex. The characteristics of all the observed stars are made available, along with those of the Canes Venatici I dwarf galaxy that have been analysed in a companion paper.
- ID:
- ivo://CDS.VizieR/VII/208
- Title:
- Faint Galaxies at the North Galactic Pole
- Short Name:
- VII/208
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The North Galactic Pole Canada-France-Hawaii Telescope Catalogue of faint galaxies is made available. We provide positions, photometric and structural parameters for more than 50000 galaxies. The J and F magnitudes were obtained from IIIaJ and IIIaF CFHT prime focus plates respectively. This catalogue have been used in many studies of faint galaxy properties. Galaxy counts, colour distributions and clustering properties of faint galaxies have been obtained with these data. Statistical properties of stars have been studied as well. For details refer to Infante and Pritchet (1992ApJS...83..237I), Pritchet and Infante (1992ApJ...399L..35P), Infante (1994A&A...282..353), Infante (1994A&AS..107..413I) and Infante and Pritchet (1995ApJ...439..565I). The magnitude errors range from: +/-0.3mag at J=24 to less than +/-0.1 at J=20 +/-0.3mag at F=23 to less than +/-0.1 at F=19 The rms uncertainty in the zero points is 0.022 (J) and 0.038 (F)
