- ID:
- ivo://CDS.VizieR/J/MNRAS/452/2606
- Title:
- Deep echelle spectrophotometry of NGC3918
- Short Name:
- J/MNRAS/452/2606
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemical content of the planetary nebula NGC 3918 is investigated through deep, high-resolution (R~40000) UVES (Ultraviolet-Visual Echelle Spectrograph) at VLT (Very Large Telescope) spectrophotometric data. We identify and measure more than 750 emission lines, making ours one of the deepest spectra ever taken for a planetary nebula. Among these lines we detect very faint lines of several neutron-capture elements (Se, Kr, Rb, and Xe), which enable us to compute their chemical abundances with unprecedented accuracy, thus constraining the efficiency of the s-process and convective dredge-up in NGC 3918 progenitor star. We find that Kr is strongly enriched in NGC 3918 and that Se is less enriched than Kr, in agreement with the results of previous papers and with predicted s-process nucleosynthesis. We also find that Xe is not as enriched by the s-process in NGC 3918 as is Kr and, therefore, that neutron exposure is typical of modestly subsolar metallicity asymptotic giant branch (AGB) stars. A clear correlation is found when representing [Kr/O] versus log(C/O) for NGC 3918 and other objects with detection of multiple ions of Kr in optical data, confirming that carbon is brought to the surface of AGB stars along with s-processed material during third dredge-up episodes, as predicted by nucleosynthesis models. We also detect numerous refractory element lines (Ca, K, Cr, Mn, Fe, Co, Ni, and Cu) and a large number of metal recombination lines of C, N, O, and Ne. We compute physical conditions from a large number of diagnostics, which are highly consistent among themselves assuming a three-zone ionization scheme. Thanks to the high ionization of NGC 3918 we detect a large number of recombination lines of multiple ionization stages of C, N, O and Ne. The abundances obtained for these elements by using recently determined state-of-the-art ionization correction factor (ICF) schemes or simply adding ionic abundances are in very good agreement, demonstrating the quality of the recent ICF scheme for high-ionization planetary nebulae.
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- ID:
- ivo://CDS.VizieR/J/ApJ/654/915
- Title:
- Deep FORS1 BR photometry of omega Cen
- Short Name:
- J/ApJ/654/915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep photometric survey performed with the VLT FORS1 aimed at investigating the complex main-sequence structure of the stellar system Centauri. We confirm the presence of a double main sequence and identify its blue component (bMS) over a large field of view up to 26' from the cluster center. We found that bMS stars are significantly more concentrated toward the cluster center than the other "normal" MS stars. The bMS morphology and its position in the CMD have been used to constrain the helium overabundance required to explain the observed MS morphology.
- ID:
- ivo://CDS.VizieR/J/ApJ/758/135
- Title:
- DEEP2 galaxies with UV spectra in the EGS
- Short Name:
- J/ApJ/758/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate galactic-scale outflowing winds in 72 star-forming galaxies at z~1 in the Extended Groth Strip. Galaxies were selected from the DEEP2 survey and follow-up LRIS spectroscopy was obtained covering Si II, C IV, Fe II, Mg II, and Mg I lines in the rest-frame ultraviolet. Using Galaxy Evolution Explorer (GALEX), Hubble Space Telescope (HST), and Spitzer imaging available for the Extended Groth Strip, we examine galaxies on a per-object basis in order to better understand both the prevalence of galactic outflows at z~1 and the star-forming and structural properties of objects experiencing outflows. Gas velocities, measured from the centroids of Fe II interstellar absorption lines, are found to span the interval [-217,+155]km/s. We find that ~40% (10%) of the sample exhibits blueshifted Fe II lines at the 1{sigma} (3{sigma}) level. We also measure maximal outflow velocities using the profiles of the Fe II and Mg II lines; we find that Mg II frequently traces higher velocity gas than Fe II. Using quantitative morphological parameters derived from the HST imaging, we find that mergers are not a prerequisite for driving outflows. More face-on galaxies also show stronger winds than highly inclined systems, consistent with the canonical picture of winds emanating perpendicular to galactic disks. In light of clumpy galaxy morphologies, we develop a new physically motivated technique for estimating areas corresponding to star formation. We use these area measurements in tandem with GALEX-derived star formation rates (SFRs) to calculate SFR surface densities. At least 70% of the sample exceeds an SFR surface density of 0.1M_{sun}_/yr/kpc2, the threshold necessary for driving an outflow in local starbursts. At the same time, the outflow detection fraction of only 40% in Fe II absorption provides further evidence for an outflow geometry that is not spherically symmetric. We see a ~3{sigma} trend between outflow velocity and SFR surface density, but no significant trend between outflow velocity and SFR. Higher resolution data are needed in order to test the scaling relations between outflow velocity and both SFR and SFR surface density predicted by theory.
- ID:
- ivo://nasa.heasarc/xdeep2
- Title:
- DEEP2 Galaxy Redshift Survey Fields Chandra Point Source Catalog
- Short Name:
- XDEEP2
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains the X-ray point-source catalog produced from the Chandra Advanced CCD Imaging Spectrometer (ACIS-I) observations of the combined ~3.2 deg<sup>2</sup> DEEP2 (XDEEP2) survey fields, which consist of four ~ 0.7 - 1.1 deg<sup>2</sup> fields. The combined total exposures across all four XDEEP2 fields range from ~ 10 ks to 1.1 Ms. The authors detect X-ray point sources in both the individual ACIS-I observations and the overlapping regions in the merged (stacked) images. They find a total of 2976 unique X-ray sources within the survey area with an expected false-source contamination of ~ 30 sources (<~ 1%). In their paper, the authors present the combined log N-log S distribution of sources detected across the XDEEP2 survey fields and find good agreement with the Extended Chandra Deep Field and Chandra-COSMOS fields to f_(X,0.5-2keV)_ ~ 2 x 10<sup>-16</sup> erg cm<sup>-1</sup> s<sup>-1</sup>. Given the large survey area of XDEEP2, they additionally place relatively strong constraints on the log N-log S distribution at high fluxes (f_(X,0.5-2keV) ~ 3 x 10<sup>-14</sup> erg cm<sup>-1</sup> s<sup>-1</sup>), and find a small systematic offset (a factor ~ 1.5) toward lower source numbers in this regime, when compared to smaller area surveys. The number counts observed in XDEEP2 are in close agreement with those predicted by X-ray background synthesis models. Additionally, the authors present a Bayesian-style method for associating the X-ray sources with optical photometric counterparts in the DEEP2 catalog (complete to R<sub>AB</sub> < 25.2) and find that 2126 (~ 71.4% +/- 2.8%) of the 2976 X-ray sources presented here have a secure optical counterpart with a <~ 6% contamination fraction. The present table provides the DEEP2 optical source properties (e.g., magnitude, redshift) as part of the X-ray-optical counterpart catalog. This table was created by the HEASARC in October 2012 based on electronic versions of Tables 5 and 7 from the reference paper which were obtained from the ApJS web site. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/ApJS/193/14
- Title:
- DEEP3 Galaxy Redshift Survey: GOODS-N field
- Short Name:
- J/ApJS/193/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic observations in the GOODS-N field completed using DEIMOS on the Keck II telescope as part of the DEEP3 Galaxy Redshift Survey (M. C. Cooper et al. 2011, in preparation). Observations of 370 unique targets down to a limiting magnitude of R_AB_=24.4 yielded 156 secure redshifts. In addition to redshift information, we provide sky-subtracted one- and two-dimensional spectra of each target. Observations were conducted following the procedures of the Team Keck Redshift Survey (TKRS, Cat. J/AJ/127/3121), thereby producing spectra that augment the TKRS sample while maintaining the uniformity of its spectral database.
- ID:
- ivo://CDS.VizieR/J/ApJ/654/115
- Title:
- DEEP2 Galaxy Redshift Survey: SDSS QSOs
- Short Name:
- J/ApJ/654/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the clustering of Deep Extragalactic Evolutionary Probe 2 (DEEP2) galaxies at 0.7<z<1.4 around quasars identified using both the Sloan Digital Sky Survey (SDSS) and DEEP2 surveys. We measure the two-point cross-correlation of a sample of 36 optically selected, spectroscopically identified quasars from the SDSS and 16 more found in the DEEP2 survey with the full DEEP2 galaxy sample over scales 0.1h^-1^MPc<r_p_<10h^-1^Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/813/100
- Title:
- Deep GALEX NUV survey of the Kepler field. I.
- Short Name:
- J/ApJ/813/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report observations of a deep near-ultraviolet (NUV) survey of the Kepler field made in 2012 with the Galaxy Evolution Explorer (GALEX) Complete All-Sky UV Survey Extension (CAUSE). The GALEX-CAUSE Kepler survey (GCK) covers 104 square degrees of the Kepler field and reaches a limiting magnitude of NUV~=22.6 at 3{sigma}. Analysis of the GCK survey has yielded a catalog of 660928 NUV sources, of which 475164 are cross-matched with stars in the Kepler Input Catalog. Approximately 327 of 451 confirmed exoplanet host stars and 2614 of 4696 candidate exoplanet host stars identified by Kepler have NUV photometry in the GCK survey. The GCK catalog should enable the identification and characterization of UV-excess stars in the Kepler field (young solar-type and low-mass stars, chromospherically active binaries, white dwarfs, horizontal branch stars, etc.), and elucidation of various astrophysics problems related to the stars and planetary systems in the Kepler field.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/43
- Title:
- Deep GALEX observations of the Coma cluster
- Short Name:
- J/ApJS/190/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a source catalog from a deep 26ks Galaxy Evolution Explorer (GALEX) observation of the Coma cluster in the far-UV (FUV; 1530{AA}) and near-UV (NUV; 2310{AA}) wavebands. The observed field is centered ~0.9{deg} (1.6Mpc) southwest of the Coma core in a well-studied region of the cluster known as "Coma-3". The entire field is located within the apparent virial radius of the Coma cluster, and has optical photometric coverage with Sloan Digital Sky Survey (SDSS) and deep spectroscopic coverage to r~21. We detect GALEX sources to NUV=24.5 and FUV=25.0, which corresponds to a star formation rate of ~10^-3^M_{sun}_/yr for galaxies at the distance of Coma. We have assembled a catalog of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically confirmed Coma member galaxies (in fig. 1) that span a large range of galaxy types from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is ~80% complete to NUV=23 and FUV=23.5. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/404/1005
- Title:
- Deep 15GHz survey (9C continued)
- Short Name:
- J/MNRAS/404/1005
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 9C survey of radio sources with the Ryle Telescope at 15.2GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array. In our first paper we described three regions of the survey, constituting a total area of to a completeness limit of ~25mJy. Here we present results from series of deeper regions, amounting to an area of 115deg^2^ complete to ~10mJy and of 29deg^2^ complete to ~5.5mJy. The compound source catalogue contains a total of 643 sources.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1212
- Title:
- Deep 20GHz survey of CDFS and SDSS Stripe 82
- Short Name:
- J/MNRAS/439/1212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a source catalogue and first results from a deep, blind radio survey carried out at 20GHz with the Australia Telescope Compact Array, with follow-up observations at 5.5, 9 and 18GHz. The Australia Telescope 20GHz (AT20G) deep pilot survey covers a total area of 5deg^2^ in the Chandra Deep Field South and in Stripe 82 of the Sloan Digital Sky Survey. We estimate the survey to be 90% complete above 2.5mJy. Of the 85 sources detected, 55percent have steep spectra ({alpha}_1.4_^20^<-0.5) and 45% have flat or inverted spectra ({alpha}_1.4_^20^>=-0.5). The steep-spectrum sources tend to have single power-law spectra between 1.4 and 18GHz, while the spectral indices of the flat- or inverted-spectrum sources tend to steepen with frequency. Among the 18 inverted-spectrum ({alpha}_1.4_^20^>=0.0) sources, 10 have clearly defined peaks in their spectra with {alpha}_1.4_^5.5^>0.15 and {alpha}_9_^18^<-0.15. On a 3-yr time-scale, at least 10 sources varied by more than 15percent at 20GHz, showing that variability is still common at the low flux densities probed by the AT20G-deep pilot survey.