- ID:
- ivo://CDS.VizieR/J/ApJ/772/26
- Title:
- AGN with WISE. II. The NDWFS Bootes field
- Short Name:
- J/ApJ/772/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stern et al. (2012ApJ...753...30S, Paper I) presented a study of Wide-field Infrared Survey Explorer (WISE) selection of active galactic nuclei (AGNs) in the 2deg^2^ COSMOS field, finding that a simple criterion W1-W2>=0.8 provides a highly reliable and complete AGN sample for W2<15.05, where the W1 and W2 passbands are centered at 3.4{mu}m and 4.6{mu}m, respectively. Here we extend this study using the larger 9deg^2^ NOAO Deep Wide-Field Survey Bootes field which also has considerably deeper WISE observations than the COSMOS field, and find that this simple color cut significantly loses reliability at fainter fluxes. We define a modified selection criterion combining the W1-W2 color and the W2 magnitude to provide highly reliable or highly complete AGN samples for fainter WISE sources. In particular, we define a color-magnitude cut that finds 130+/-4deg^-2^ AGN candidates for W2<17.11 with 90% reliability. Using the extensive UV through mid-IR broadband photometry available in this field, we study the spectral energy distributions of WISE AGN candidates. We find that, as expected, the WISE AGN selection can identify highly obscured AGNs, but that it is biased toward objects where the AGN dominates the bolometric luminosity output. We study the distribution of reddening in the AGN sample and discuss a formalism to account for sample incompleteness based on the step-wise maximum-likelihood method of Efstathiou et al. The resulting dust obscuration distributions depend strongly on AGN luminosity, consistent with the trend expected for a receding torus. At L_AGN_~3x10^44^erg/s, 29%+/-7% of AGNs are observed as Type 1, while at ~4x10^45^erg/s the fraction is 64%+/-13%. The distribution of obscuration values suggests that dust in the torus is present as both a diffuse medium and in optically thick clouds.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/601/A10
- Title:
- A grid of MARCS model atmospheres for S stars
- Short Name:
- J/A+A/601/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S-type stars are late-type giants whose atmospheres are enriched in carbon and s-process elements because of either extrinsic pollution by a binary companion or intrinsic nucleosynthesis and dredge-up on the thermally-pulsing asymptotic giant branch. A grid of MARCS model atmospheres has been computed for S stars, covering the range 2700<=Teff(K)<=4000, 0.50<=C/O<0.99, 0<=logg<=5, [Fe/H]=0., -0.5dex, and [s/Fe]= 0, 1, and 2 dex (where the latter quantity refers to the global overabundance of s-process elements). The MARCS models make use of a new ZrO line list. Synthetic spectra computed from these models are used to derive photometric indices in the Johnson and Geneva systems, as well as TiO and ZrO band strengths. A method is proposed to select the model best matching any given S star, a non-trivial operation since the grid contains more than 3500 models covering a five-dimensional parameter space. The method is based on the comparison between observed and synthetic photometric indices and spectral band strengths, and has been applied on a vast subsample of the Henize sample of S stars. Our results confirm the old claim by Piccirillo (1980MNRAS.190..441P) that ZrO bands in warm S stars (Teff > 3200K) are not caused by the C/O ratio being close to unity, as traditionally believed, but rather by some Zr overabundance. The TiO and ZrO band strengths, combined with V-K and J-K photometric indices, are used to select Teff, C/O, [Fe/H] and [s/Fe]. The Geneva U-B_1 and B_2-V_1 indices (or any equivalent) are good at selecting the gravity. The defining spectral features of dwarf S stars are outlined, but none is found among the Henize S stars. More generally, it is found that, at Teff=3200K, a change of C/O from 0.5 to 0.99 has a strong impact on V-K (2mag). Conversely, a range of 2 mag in V-K corresponds to a 200K shift along the (Teff, V-K) relationship (for a fixed C/O value). Hence, the use of a (Teff, V-K) calibration established for M stars will yield large errors for S stars, so that a specific calibration must be used, as provided in the present paper. Using the atmospheric parameters derived by our method for the sample of Henize S stars, we show that the extrinsic-intrinsic dichotomy among S stars reveals itself very clearly as a bimodal distribution in the effective temperatures. Moreover, the increase of s-process element abundances with increasing C/O ratios and decreasing temperatures is apparent among intrinsic stars, confirming theoretical expectations.
- ID:
- ivo://CDS.VizieR/J/AJ/139/434
- Title:
- A1763 infrared and optical photometry
- Short Name:
- J/AJ/139/434
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric analysis of the galaxy cluster Abell 1763 at visible and infrared wavelengths. Included are fully reduced images in r', J, H, and Ks obtained using the Palomar 200in telescope, as well as the IRAC and MIPS images from Spitzer. The cluster is covered out to approximately 3 virial radii with deep 24um imaging (a 5{sigma} depth of 0.2mJy). This same field of ~40'x40' is covered in all four IRAC bands as well as the longer wavelength MIPS bands (70 and 160um). The r' imaging covers ~0.8deg^2^ down to 25.5mag, and overlaps with most of the MIPS field of view. The J, H, and Ks images cover the cluster core and roughly half of the filament galaxies, which extend toward the neighboring cluster, Abell 1770. This first, in a series of papers on Abell 1763, discusses the data reduction methods and source extraction techniques used for each data set. We present catalogs of infrared sources (with 24 and/or 70um emission) and their corresponding emission in the optical (u', g', r', i', z'), and near- to far-IR (J, H, Ks, IRAC, and MIPS 160um). We provide the catalogs and reduced images to the community through the NASA/IPAC Infrared Science Archive.
- ID:
- ivo://CDS.VizieR/II/298
- Title:
- AKARI/FIS All-Sky Survey Point Source Catalogues
- Short Name:
- II/298
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AKARI Infrared Astronomical Satellite observed the whole sky in the far infrared (50-180{mu}m) and the mid-infrared (9 and 18{mu}m) between May 2006 and August 2007 (Murakami et al. 2007PASJ...59S.369M) The AKARI/FIS All-Sky Survey Bright Source Catalog Version 1.0 provides positions and fluxes for 427071 point sources in the 4 far-infrared wavelengths centered at 65, 90, 140 and 160{mu}m (see filter characteristics in the "Note (1)" section below)
- ID:
- ivo://CDS.VizieR/J/A+A/605/A74
- Title:
- AKARI fluxes of ATLAS3D early-type galaxies
- Short Name:
- J/A+A/605/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The star formation properties of early-type galaxies (ETGs) are currently the subject of considerable interest, particularly whether they differ from the star formation properties of gas-rich spirals. We perform a systematic study of star formation in a large sample of local ETGs with polycyclic aromatic hydrocarbon (PAH) and dust emission, focusing on the star formation rates (SFRs) and star formation efficiencies (SFEs) of the galaxies. Our sample is composed of the 260 ETGs from the ATLAS^3D^ survey, from which we used the cold gas measurements (HI and CO). We estimated the SFRs from stellar, PAH, and dust fits to spectral energy distributions created from new AKARI measurements and with literature data from WISE and 2MASS. The mid-infrared luminosities of non-CO-detected galaxies are well correlated with their stellar luminosities, showing that they trace (circum)stellar dust emission. CO-detected galaxies show an excess above these correlations, uncorrelated with their stellar luminosities, indicating that they likely contain PAHs and dust of interstellar origin. PAH and dust luminosities of CO-detected galaxies show tight correlations with their molecular gas masses; the derived current SFRs are typically 0.01-1M_{sun}_/yr. These SFRs systematically decrease with stellar age at fixed stellar mass, while they correlate nearly linearly with stellar mass at fixed age. The majority of local ETGs follow the same star formation law as local star-forming galaxies and their current SFEs do not depend on either stellar mass or age. Our results clearly indicate that molecular gas is fueling current star formation in local ETGs, which appear to acquire this gas via mechanisms regulated primarily by stellar mass. The current SFEs of local ETGs are similar to those of local star-forming galaxies, indicating that their low SFRs are likely due to smaller cold gas fractions rather than a suppression of star formation.
- ID:
- ivo://CDS.VizieR/J/A+A/514/A2
- Title:
- AKARI/HIP and AKARI/2MASS samples
- Short Name:
- J/A+A/514/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AKARI, a Japanese infrared space mission, has performed an All-Sky Survey in six infrared-bands from 9 to 180um with higher spatial resolutions and better sensitivities than the Infrared Astronomical Satellite (IRAS). We investigate the mid-infrared (9 and 18um) point source catalog (PSC) obtained with the Infrared Camera (IRC) onboard AKARI, in order to understand the infrared nature of the known objects and to identify previously unknown objects. Color-color diagrams and a color-magnitude diagram were plotted with the AKARI-IRC PSC and other available all-sky survey catalogs. We combined the Hipparcos astrometric catalog and the 2MASS all-sky survey catalog with the AKARI-IRC PSC. We furthermore searched literature and SIMBAD astronomical database for object types, spectral types, and luminosity classes. We identified the locations of representative stars and objects on the color-magnitude and color-color diagram schemes. The properties of unclassified sources can be inferred from their locations on these diagrams.
- ID:
- ivo://CDS.VizieR/II/297
- Title:
- AKARI/IRC mid-IR all-sky Survey
- Short Name:
- II/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AKARI Infrared Astronomical Satellite observed the whole sky in the far infrared (50-180{mu}m) and the mid-infrared (9 and 18{mu}m) between May 2006 and August 2007 (Murakami et al. 2007PASJ...59S.369M) The AKARI/IRC Point Source Catalogue Version 1.0 provides positions and fluxes for 870,973 sources observed with the InfraRed Camera (IRC): 844,649 sources in the S9W filter, and 194,551 sources in the L18W filter; the "Note (1)" section below provides a summary of the IRC filter characteristics.
- ID:
- ivo://CDS.VizieR/J/PASJ/65/34
- Title:
- AKARI IRC slow-scan asteroid catalog, AcuA-ISS
- Short Name:
- J/PASJ/65/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an asteroidal catalog from the mid-infrared wavelength region using the slow-scan observation mode obtained by the Infrared Camera (IRC) on-board the Japanese infrared satellite AKARI. An archive of IRC slow-scan observations comprising about 1000 images was used to search for serendipitous encounters of known asteroids. We have determined the geometric albedos and diameters for 88 main-belt asteroids, including two asteroids in the Hilda region, and compared these, where possible, with previously published values. Approximately one-third of the acquired data reflects new asteroidal information. Some bodies classified as C or D-type with high albedo were also identified in the catalog.
- ID:
- ivo://CDS.VizieR/J/AJ/144/179
- Title:
- AKARI-LMC Point-source catalog
- Short Name:
- J/AJ/144/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a near- to mid-infrared point-source catalog of five photometric bands at 3.2, 7, 11, 15, and 24{mu}m for a 10deg^2^ area of the Large Magellanic Cloud (LMC) obtained with the Infrared Camera on board the AKARI satellite. To cover the survey area the observations were carried out at three separate seasons from 2006 May to June, 2006 October to December, and 2007 March to July. The 10{sigma} limiting magnitudes of the present survey are 17.9, 13.8, 12.4, 9.9, and 8.6mag at 3.2, 7, 11, 15, and 24{mu}m, respectively. The photometric accuracy is estimated to be about 0.1mag at 3.2{mu}m and 0.06-0.07 mag in the other bands. The position accuracy is 0.3" at 3.2, 7, and 11{mu}m and 1.0" at 15 and 24{mu}m. The sensitivities at 3.2, 7, and 24{mu}m are roughly comparable to those of the Spitzer SAGE LMC point-source catalog, while the AKARI catalog provides the data at 11 and 15 {mu}m, covering the mid-infrared spectral range contiguously. Two types of catalog are provided: a Catalog and an Archive. The Archive contains all the detected sources, while the Catalog only includes the sources that have a counterpart in the Spitzer SAGE point-source catalog. The Archive contains about 650,000, 140,000, 97,000, 43,000, and 52,000 sources at 3.2, 7, 11, 15, and 24{mu}m, respectively. Based on the catalog, we discuss the luminosity functions at each band, the color-color diagram, and the color-magnitude diagram using the 3.2, 7, and 11{mu}m band data. Stars without circumstellar envelopes, dusty C-rich and O-rich stars, young stellar objects, and background galaxies are located at distinct regions in the diagrams, suggesting that the present catalog is useful for the classification of objects toward the LMC.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A24
- Title:
- AKARI NEP-Deep field mid-IR source catalogue
- Short Name:
- J/A+A/537/A24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalogue of mid-IR sources using the AKARI NEP-Deep survey. The InfraRed Camera (IRC) onboard AKARI has a comprehensive mid-IR wavelength coverage with 9 photometric bands at 2-24 micron. We designed the catalogue to include most of sources detected in 7, 9, 11, 15, and 18 micron bands, and found 7284 sources in a 0.67 square degree area.
