- ID:
- ivo://CDS.VizieR/J/ApJS/185/433
- Title:
- SWIRE/Chandra survey in Lockman Hole Field
- Short Name:
- J/ApJS/185/433
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a moderate-depth (70ks), contiguous 0.7deg^2^ Chandra survey in the Lockman Hole Field of the Spitzer/SWIRE Legacy Survey coincident with a completed, ultra-deep VLA survey with deep optical and near-infrared imaging in-hand. The primary motivation is to distinguish starburst galaxies and active galactic nuclei (AGNs), including the significant, highly obscured (logN_H_>23) subset. Chandra has detected 775 X-ray sources to a limiting broadband (0.3-8keV) flux ~4x10^-16^erg/cm^2^/s. We present the X-ray catalog, fluxes, hardness ratios, and multi-wavelength fluxes. The logN versus logS agrees with those of previous surveys covering similar flux ranges. The Chandra and Spitzer flux limits are well matched: 771 (99%) of the X-ray sources have infrared (IR) or optical counterparts, and 333 have MIPS 24um detections. There are four optical-only X-ray sources and four with no visible optical/IR counterpart. The very deep (~2.7uJy rms) VLA data yield 251 (>4{sigma}) radio counterparts, 44% of the X-ray sources in the field. More than 40% of the X-ray sources in the VLA field are radio-loud using the classical definition, RL. The majority of these are red and relatively faint in the optical so that the use of RL to select those AGNs with the strongest radio emission becomes questionable. Using the 24um to radio flux ratio (q_24_) instead results in 13 of the 147 AGNs with sufficient data being classified as radio-loud, in good agreement with the ~10% expected for broad-lined AGNs based on optical surveys. We conclude that q_24_ is a more reliable indicator of radio-loudness. Use of RL should be confined to the optically selected type 1 AGN.
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Search Results
- ID:
- ivo://CDS.VizieR/II/255
- Title:
- SWIRE ELAIS N1 Source Catalogs
- Short Name:
- II/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Wide-area InfraRed Extragalactic survey (SWIRE; Lonsdale et al., 2003PASP..115..897L) Version 1.0 data products release includes an image atlas and a source catalogs from the first of the 6 SWIRE fields to be observed by Spitzer, the ELAIS-N1 field. The release includes both Spitzer IRAC and MIPS mid/far-infrared data products and also Ug'r'i'Z optical data covering the same regions of the sky from the Isaac Newton Telescope (INT) Wide-Field Survey (WFS; McMahon et al., 2001NewAR..45...97M; Gonzalez-Solares et al., 2004, MNRAS, in press). The Version 1.0 SWIRE ELAIS-N1 Source Catalogs have three parts: (1) a catalog including IRAC and MIPS 24{mu}m sources which have been band-merged together. The Spitzer source list has been positionally matched to the optical source list and we report optical position and 5-band magnitude data for each successful match. This catalog contains only sources lying with the region which has full coverage in all four IRAC bands; (2) a 70{mu}m catalog; and (3) a 160{mu}m catalog. The longer wavelength catalogs have not been band-merged with the IRAC+24{mu}m catalog or the optical source list at this time because of complex source confusion issues. The two MIPS-Ge catalogs cover the full area scanned by each MIPS-array, except for areas of low coverage around each edge, and are not restricted to the full IRAC coverage area. All data are available at http://data.spitzer.caltech.edu/popular/swire/20041027_enhanced_v1_EN1
- ID:
- ivo://CDS.VizieR/J/A+A/476/151
- Title:
- SWIRE ELAIS-S1 IR-peak galaxy IR fluxes
- Short Name:
- J/A+A/476/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Main data on the IR-peakers sample in the SWIRE ELAIS-S1 field. For each IR-peak galaxy, we report R band magnitude (AB units, from the ESIS survey, Berta et al., 2006A&A...451..881B), Spitzer SWIRE fluxes (Lonsdale et al., 2003PASP..115..897L, 2004ApJS..154...54L), photometric redshift (based on Hyper-z fit, Bolzonella et al., 2000A&A...363..476B), the stellar mass and its minimal-maximal range. The stellar mass estimate is based on mixed stellar population (MSP) synthesis (Berta et al., 2004A&A...418..913B). The minimal and maximal stellar masses are obtained by exploring the SFH-extinction parameter space with the Adaptive Simulated Annealing algorithm (Ingber et al., 2001, http://www.ingber.com/asa01_lecture.pdf). See the paper associated to these data for more details.
- ID:
- ivo://CDS.VizieR/II/290
- Title:
- SWIRE Photometric Redshift Catalogue
- Short Name:
- II/290
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the SWIRE Photometric Redshift Catalogue 1025119 redshifts of unprecedented reliability and of accuracy comparable with or better than previous work. Our methodology is based on fixed galaxy and quasi-stellar object templates applied to data at 0.36-4.5um, and on a set of four infrared emission templates fitted to infrared excess data at 3.6-170um. The galaxy templates are initially empirical, but are given greater physical validity by fitting star formation histories to them, which also allows us to estimate stellar masses.
6555. SWIRE/SDSS quasars
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/1252
- Title:
- SWIRE/SDSS quasars
- Short Name:
- J/MNRAS/386/1252
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the properties of dusty tori in active galactic nuclei from the comparison of observed spectral energy distributions (SEDs) of SDSS quasars and a precomputed grid of torus models. The observed SEDs comprise SDSS photometry, Two-Micron All-Sky Survey J, H and K data, whenever available, and mid-infrared (mid-IR) data from the Spitzer Wide-area InfraRed Extragalactic Survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/1206
- Title:
- SWIRE/SDSS quasars. II. Type 2 AGN
- Short Name:
- J/MNRAS/399/1206
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is the second part of a work investigating the properties of dusty tori in active galactic nuclei (AGN) by means of multicomponent spectral energy distribution (SED) fitting. It focuses on low-luminosity, low-redshift (z<=0.25) AGN selected among emission line galaxies in the overlapping regions between Spitzer Wide-area Infrared Extragalactic Survey (SWIRE) and Sloan Digital Sky Survey Data Release 4 as well as X-ray, radio and mid-infrared selected type 2 AGN samples from the literature. The available multiband photometry covers the spectral range from the u band up to 160um. Using a standard chi^2^ minimization, the observed SED of each object is fit to a set of multicomponent models comprising a stellar component, a high optical depth (tau_9.7_>=1.0) torus and cold emission from a starburst (SB). The torus components assigned to the majority of the objects were those of the highest optical depth of our grid of models (tau_9.7_=10.0). The contribution of the various components (stars, torus, SB) is reflected in the position of the objects on the Infrared Array Camera (IRAC) colour diagram, with star-, torus- and SB-dominated objects occupying specific areas of the diagrams and composite objects lying in between.
6557. SX Phe
- ID:
- ivo://CDS.VizieR/J/AJ/106/2493
- Title:
- SX Phe
- Short Name:
- J/AJ/106/2493
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Simultaneous photometric (uvbyBeta) and spectrographic observations of SX Phe are described. Analysis of the light and velocity frequency spectra are performed. It is shown that all frequencies detected are harmonics or combinations of the fundamental and first harmonic frequencies. Intrinsic (b-y) and c1 values used in conjunction with a model-atmosphere grid appropriate for a star with [M/H]=-1.0 yields <Teff>=7360K and <logg>=3.90. Standard evolutionary models indicate the mass is 1.13 M_{sun}_ and <Mv> value is +2.9. The radial-velocity data indicate a mean radial velocity of -37km/s and a total range of 38km/s.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/947
- Title:
- SX Phe stars in Fornax. II.
- Short Name:
- J/ApJ/685/947
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out an intensive survey of the northern region of the Fornax dwarf spheroidal galaxy with the aim of detecting the galaxy's short-period pulsating stars (P<0.25 days). Observations collected over three consecutive nights with the Wide Field Imager of the 2.2m MPI telescope at ESO allowed us to detect 85 high-amplitude (0.20-1.00mag in B light) variable stars with periods in the range from 0.046 to 0.126 days, similar to SX Phoenicis stars in Galactic metal-poor stellar populations. The plots of the observed periods vs. the B and V magnitudes show a dispersion largely exceeding the observational errors. To disentangle the matter, we separated the first-overtone from the fundamental-mode pulsators and tentatively identified a group of subluminous variables, about 0.35mag fainter than the others. Their nature as either metal-poor intermediate-age stars or stars formed by the merging of close binary systems is discussed. The rich sample of the Fornax variables also led us to reconstruct the period-luminosity relation for short-period pulsating stars. An excellent linear fit, M_V_=-1.83(+/-0.08)-3.65(+/-0.07)logP_F_, was obtained using 153 {delta} Scuti and SX Phoenicis stars in a number of different stellar systems.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/342
- Title:
- SX Phe stars in globular clusters
- Short Name:
- J/MNRAS/419/342
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This study is aimed at investigating the period-luminosity relation of SX Phoenicis (SX Phe) pulsators in Galactic globular clusters (GGCs) and Local Group dwarf galaxies. We verify isochrone-fitting distances of 46 GGCs by fitting their main sequences to a carefully chosen set of nearby, unevolved subdwarfs.
6560. SX Phe stars in NGC 5053
- ID:
- ivo://CDS.VizieR/J/AJ/110/1186
- Title:
- SX Phe stars in NGC 5053
- Short Name:
- J/AJ/110/1186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a major search for photometrically variable blue straggler stars (BSs) in the extremely metal-poor globular cluster NGC 5053 are presented. The survey is based on photometry of over 200 CCD frames (BVI passbands) taken on 18 nights between 1985 and 1994. Five of the 16 BSs monitored for variability are identified as SX Phe stars and their photometric characteristics derived. These five stars are among the shortest-period (49<P<57min), lowest luminosity (3.0<~M_V<~3.3mag), smallest amplitude (0.08<~A_V<~0.25mag) SX Phe stars presently known. Their colors and locations in both B and V period-luminosity (P-L) diagrams suggest that four of the stars (blue stragglers 11, 13, 14, and 15 in the Nemec & Cohen 1989 catalog (1989ApJ...336..780N) are fundamental-mode pulsators, while the fifth and bluest star, No. 7, appears to be a first-overtone pulsator. One of the stars, No. 11, exhibits cycle-to-cycle light variations that are consistent with multimode pulsations; however, not enough photometric information is available to derive its secondary pulsation period. Masses for the stars, estimated directly from the general equation of stellar pulsation and relative to the RR Lyrae stars, range from 0.53M_{sun}_ (NC7) to 1.8M_{sun}_ (NC13). The SX Phe stars are used to derive improved P-L-[Fe/H] relations for SX Phe stars, from which a revised distance modulus of (m-M)0=16.06 is obtained for NGC 5053.