- ID:
- ivo://CDS.VizieR/J/MNRAS/366/1265
- Title:
- CENSORS infrared imaging
- Short Name:
- J/MNRAS/366/1265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Combined EIS-NVSS Survey of Radio Sources (CENSORS) is a 1.4-GHz radio survey selected from the National Radio Astronomy Observatories (NRAO) Very Large Array (VLA) Sky Survey (NVSS) and complete to a flux density of 7.2mJy. It targets the European Southern Observatory (ESO) Imaging Survey (EIS) Patch D, which is a 3x2{deg}^2^ field centred on right ascension 09:51:36.0 and declination 21:00:00 (J2000). This paper presents K-band imaging of 142 of the 150 CENSORS sources. The primary motivation for beginning infrared imaging of the sample was to identify the host galaxies of ~30 per cent of sources for which the EIS I-band imaging failed to produce a likely candidate. In addition, K-band magnitudes allow photometric redshift estimation and IK colours aid the identification of host galaxies (which are typically old, red ellipticals). Of the sources observed in the I and K bands, four remain undetected, possibly indicating high redshifts for the host galaxies, and eight involve complicated radio structures, or several candidate host galaxies, which have yet to be resolved. Thus, the host galaxy identifications are brought to 92 per cent completeness.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/880/7
- Title:
- Census of the Local Universe survey. I. CLU-Halpha
- Short Name:
- J/ApJ/880/7
- Date:
- 03 Nov 2021 07:51:08
- Publisher:
- CDS
- Description:
- We present the Census of the Local Universe (CLU) narrowband survey to search for emission-line (H{alpha}) galaxies. CLU-H{alpha} has imaged ~3{pi} of the sky (26470deg^2^) with four narrowband filters that probe a distance out to 200Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6deg^2^) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an H{alpha} flux limit of 10^-14^erg/s/cm^2^ at 90% completeness, and recovers 83% (67%) of the H{alpha} flux from cataloged galaxies in our search volume at the {Sigma}=2.5 ({Sigma}=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for {Sigma}=2.5 ({Sigma}=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional ~300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identify a known planetary nebula. These objects show that the CLU-H{alpha} survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-H{alpha} galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-H{alpha} galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/58
- Title:
- Cepheids from VVV in the southern Galactic midplane
- Short Name:
- J/ApJ/883/58
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The far side of the Milky Way's disk is one of the most concealed parts of the known universe due to extremely high interstellar extinction and point-source density toward low Galactic latitudes. Large time-domain photometric surveys operating in the near-infrared hold great potential for the exploration of these vast uncharted areas of our Galaxy. We conducted a census of distant classical and type II Cepheids along the southern Galactic midplane using near-infrared photometry from the VISTA Variables in the Via Lactea survey. We performed a machine-learned classification of the Cepheids based on their infrared light curves using a convolutional neural network. We have discovered 640 distant classical Cepheids with up to ~40mag of visual extinction and over 500 type II Cepheids, most of them located in the inner bulge. Intrinsic color indices of individual Cepheids were predicted from sparse photometric data using a neural network, allowing their use as accurate reddening tracers. They revealed a steep, spatially varying near-infrared extinction curve toward the inner bulge. Type II Cepheids in the Galactic bulge were also employed to measure robust mean selective-to-absolute extinction ratios. They trace a centrally concentrated spatial distribution of the old bulge population with a slight elongation, consistent with earlier results from RR Lyrae stars. Likewise, the classical Cepheids were utilized to trace the Galactic warp and various substructures of the Galactic disk and uncover significant vertical and radial age gradients of the thin disk population at the far side of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/AJ/156/130
- Title:
- Cepheids in M31 - PAndromeda Cepheid sample
- Short Name:
- J/AJ/156/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest Cepheid sample in M31 based on the complete Pan-STARRS1 survey of Andromeda (PAndromeda) in the r_P1_, i_P1_, and g_P1_ bands. We find 2686 Cepheids with 1662 fundamental-mode Cepheids, 307 first-overtone Cepheids, 278 type II Cepheids, and 439 Cepheids with undetermined Cepheid type. Using the method developed by Kodric et al. (2013, , Cat. J/AJ/145/106), we identify Cepheids by using a three-dimensional parameter space of Fourier parameters of the Cepheid light curves combined with a color cut and other selection criteria. This is an unbiased approach to identify Cepheids and results in a homogeneous Cepheid sample. The period-luminosity relations obtained for our sample have smaller dispersions than in our previous work. We find a broken slope that we previously observed with HST data in Kodric et al. (2013, , Cat. J/AJ/145/106), albeit with a lower significance.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/28
- Title:
- CFHTLS galaxies with faint tidal features
- Short Name:
- J/ApJ/765/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M_r'_<-19.3mag) galaxies in the magnitude range 15.5mag<r'<17mag and in the redshift range 0.04<z<0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10^10.5^M_{sun}_, and red galaxies are twice as likely to show tidal features than are blue galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/38
- Title:
- CFHTLS-SL2S-ARCS strong lens candidates
- Short Name:
- J/ApJ/749/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Strong Lensing Legacy Survey-ARCS (SARCS) sample compiled from the final T0006 data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) covering a total non-overlapping area of 159 deg^2^. We adopt a semi-automatic method to find gravitational arcs in the survey that makes use of an arc-finding algorithm. The candidate list is pruned by visual inspection and ranking to form the final SARCS sample. This list also includes some serendipitously discovered lens candidates which the automated algorithm did not detect. The SARCS sample consists of 127 lens candidates which span arc radii ~2"-18" within the unmasked area of ~150 deg^2^. Within the sample, 54 systems are promising lenses among which, we find 12 giant arcs (length-to-width ratio >= 8). We also find two radial arc candidates in SL2SJ141447+544704. From our sample, we detect a systematic alignment of the giant arcs with the major axis of the baryonic component of the putative lens in concordance with previous studies. This alignment is also observed for all arcs in the sample and does not vary significantly with increasing arc radius. The mean values of the photometric redshift distributions of lenses corresponding to the giant arcs and all arcs sample are at z~0.6.
- ID:
- ivo://CDS.VizieR/J/ApJS/178/339
- Title:
- ChaMP extended stellar survey (ChESS)
- Short Name:
- J/ApJS/178/339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 348 X-ray-emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a wide-area serendipitous survey based on archival X-ray images, with the Sloan Digital Sky Survey (SDSS-DR6). We use morphological star/galaxy separation, matching to an SDSS quasar catalog, an optical color-magnitude cut, and X-ray data-quality tests to create our catalog, the ChaMP Extended Stellar Survey (ChESS), from a sample of 2121 matched ChaMP/SDSS sources. Our cuts retain 92% of the spectroscopically confirmed stars in the original sample while excluding 99.6% of the 684 spectroscopically confirmed extragalactic sources. Fewer than 3% of the sources in our final catalog are previously identified stellar X-ray emitters. For 42 catalog members, spectroscopic classifications are available in the literature. We present new spectral classifications and H{alpha} measurements for an additional 79 stars. The catalog is dominated by main-sequence stars; we estimate the fraction of giants in ChESS is ~10%. We identify seven giant stars (including a possible Cepheid and an RR Lyrae star) as ChaMP sources, as well as three cataclysmic variables. Future papers will present analyses of source variability and comparisons of this catalog to models of stellar activity in the Galactic disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/685/463
- Title:
- ChaMPlane X-ray sources in the Galactic bulge
- Short Name:
- J/ApJ/685/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out optical and X-ray spectral analyses on a sample of 136 candidate optical counterparts of X-ray sources found in five Galactic bulge fields included in our Chandra Multiwavelength Plane Survey. We use a combination of optical spectral fitting and quantile X-ray analysis to obtain the hydrogen column density toward each object, and a three-dimensional dust model of the Galaxy to estimate the most probable distance in each case. We present the discovery of a population of stellar coronal emission sources, likely consisting of pre-main-sequence, young main-sequence, and main-sequence stars, as well as a component of active binaries of RS CVn or BY Dra type. We identify one candidate quiescent low-mass X-ray binary with a subgiant companion; we note that this object may also be an RS CVn system. We report the discovery of three new X-ray-detected cataclysmic variables (CVs) in the direction of the Galactic center (at distances <~2kpc). This number is in excess of predictions made with a simple CV model based on a local CV space density of <~10^-5^pc^-3^, and a scale height ~200pc. We discuss several possible reasons for this observed excess.
- ID:
- ivo://CDS.VizieR/J/ApJS/228/2
- Title:
- Chandra Deep Field-South survey: 7Ms sources
- Short Name:
- J/ApJS/228/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present X-ray source catalogs for the ~7Ms exposure of the Chandra Deep Field-South (CDF-S), which covers a total area of 484.2arcmin^2^. Utilizing wavdetect for initial source detection and ACIS Extract for photometric extraction and significance assessment, we create a main source catalog containing 1008 sources that are detected in up to three X-ray bands: 0.5-7.0keV, 0.5-2.0keV, and 2-7keV. A supplementary source catalog is also provided, including 47 lower-significance sources that have bright (K_s_<=23) near-infrared counterparts. We identify multiwavelength counterparts for 992 (98.4%) of the main-catalog sources, and we collect redshifts for 986 of these sources, including 653 spectroscopic redshifts and 333 photometric redshifts. Based on the X-ray and multiwavelength properties, we identify 711 active galactic nuclei (AGNs) from the main-catalog sources. Compared to the previous ~4Ms CDF-S catalogs, 291 of the main-catalog sources are new detections. We have achieved unprecedented X-ray sensitivity with average flux limits over the central ~1arcmin^2^ region of ~1.9x10^-17^, 6.4x10^-18^, and 2.7x10^-17^erg/cm^2^/s in the three X-ray bands, respectively. We provide cumulative number-count measurements observing, for the first time, that normal galaxies start to dominate the X-ray source population at the faintest 0.5-2.0keV flux levels. The highest X-ray source density reaches ~50500deg^-2^, and 47%+/-4% of these sources are AGNs (~23900deg^-2^).
- ID:
- ivo://CDS.VizieR/J/MNRAS/400/299
- Title:
- Chandra deep protocluster survey
- Short Name:
- J/MNRAS/400/299
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present X-ray point-source catalogues for a deep ~400ks Chandra ACIS-I (Advanced CCD Imaging Spectrometer) exposure of the SSA22 field. The observations are centred on a z=3.09 protocluster, which is populated by Lyman break galaxies (LBGs), Ly{alpha} emitters (LAEs) and extended Ly{alpha}-emitting blobs (LABs). The survey reaches ultimate (3 count) sensitivity limits of ~5.7x10^-17^ and ~3.0x10^-16^erg/cm^2^/s for the 0.5-2 and 2-8keV bands, respectively (corresponding to L_2-10keV_~5.7x10^42^erg/s and L_10-30keV_~2.0x10^43^erg/s at z=3.09, respectively, for an assumed photon index of {GAMMA}=1.4). These limits make SSA22 the fourth deepest extragalactic Chandra survey yet conducted, and the only one focused on a known high-redshift structure. In total, we detect 297 X-ray point sources and identify one obvious bright extended X-ray source over a ~330arcmin^2^ region. In addition to our X-ray catalogues, we provide all available optical spectroscopic redshifts and near-infrared and mid-infrared photometry available for our sources.