- ID:
- ivo://CDS.VizieR/J/ApJ/834/160
- Title:
- ugriz colors of RR Lyrae stars in SDSS Stripe 82
- Short Name:
- J/ApJ/834/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Investigation of period-color (PC) and amplitude-color (AC) relations at the maximum and minimum light can be used to probe the interaction of the hydrogen ionization front (HIF) with the photosphere and the radiation hydrodynamics of the outer envelopes of Cepheids and RR Lyraes. For example, theoretical calculations indicated that such interactions would occur at minimum light for RR Lyrae and result in a flatter PC relation. In the past, the PC and AC relations have been investigated by using either the (V-R)_MACHO_ or (V-I) colors. In this work, we extend previous work to other bands by analyzing the RR Lyraes in the Sloan Digital Sky Survey Stripe 82 Region. Multi-epoch data are available for RR Lyraes located within the footprint of the Stripe 82 Region in five (ugriz) bands. We present the PC and AC relations at maximum and minimum light in four colors: (u-g)_0_, (g-r)_0_, (r-i)_0_, and (i-z)_0_, after they are corrected for extinction. We found that the PC and AC relations for this sample of RR Lyraes show a complex nature in the form of flat, linear or quadratic relations. Furthermore, the PC relations at minimum light for fundamental mode RR Lyrae stars are separated according to the Oosterhoff type, especially in the (g-r)_0_ and (r-i)_0_ colors. If only considering the results from linear regressions, our results are quantitatively consistent with the theory of HIF-photosphere interaction for both fundamental and first overtone RR Lyraes.
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- ID:
- ivo://CDS.VizieR/J/AJ/133/1409
- Title:
- u'g'r'i'z' photometry in NGC 188
- Short Name:
- J/AJ/133/1409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We continue our series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here we present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. We fit the Padova theoretical isochrones to our data. Assuming a solar metallicity for NGC 188, we find a distance of 1700+/-100pc, an age of 7.5+/-0.7Gyr, and a reddening E(B-V) of 0.025+/-0.005. This yields a distance modulus of 11.23+/-0.14.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2210
- Title:
- u'g'r'i'z' photometry in NGC 2548 (M48)
- Short Name:
- J/AJ/127/2210
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present initial results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. While our entire observed sample covers more than 100 clusters, here we present data for NGC 2548 (M48), which is a cluster characterized in the UBV and DDO photometric systems. We compare our results to the published values from other observers and to the Padova theoretical isochrones and metallicity curves. These observations demonstrate that the u'g'r'i'z' filters can play an important role in determining the metallicity of stars and clusters. We begin this series of papers with a study of NGC 2548 because we have obtained data on this cluster not only with our main program telescope, the CTIO Curtis Schmidt, but also with the US Naval Observatory (USNO) 1.0m telescope (the telescope used to define the u'g'r'i'z' system), and with the Sloan Digital Sky Survey (SDSS) 0.5m Photometric Telescope (the photometric monitoring telescope used to calibrate the SDSS 2.5m telescope imaging data). We have used the data from this study to validate our ability to transform measurements obtained on other telescopes to the standard USNO 1.0m u'g'r'i'z' system. This validation is particularly important for very red stars, for which the original u'g'r'i'z' standard star network is poorly constrained.
- ID:
- ivo://CDS.VizieR/J/AJ/119/2598
- Title:
- u'g'r'i'z' photometry of LCRS galaxies
- Short Name:
- J/AJ/119/2598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-quality photometry in the five Sloan Digital Sky Survey filters, u', g', r', i', and z', for 2195 galaxies with spectroscopic redshifts measured by the Las Campanas Redshift Survey. In addition, a polynomial photometric redshift estimator is derived, with an uncertainty of 0.035 out to z=0.25.
- ID:
- ivo://CDS.VizieR/J/ApJS/123/377
- Title:
- u*g*r*i*z* Photometry of stars, galaxies, QSOs
- Short Name:
- J/ApJS/123/377
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog (table 5 of the paper) contains the measurements of 2262 sources, including 334 extended sources, 1915 point sources, and 13 known QSOs, in five passbands close to the u'g'r'i'z' passbands of SDSS (see the definition of the photometric system in Richards et al., 1997PASP..109...39R). Of these objects, over 1600 are measured in 15 fields covering 0.5deg^2^, with a limiting magnitude of r*<19.5, similar to the photometric limit of the SDSS spectroscopic survey.
- ID:
- ivo://CDS.VizieR/J/ApJS/127/1
- Title:
- UGRK Photometry in the Hubble Deep field region
- Short Name:
- J/ApJS/127/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detection and photometry of sources in the U_n_, G, {R}, and K_s_ bands in a 9x9 arcmin^2^ region of the sky, centered on the Hubble Deep Field, are described. The data permit construction of complete photometric catalogs to roughly U_n_=25, G=26, {R}=25.5, K_s_=20 mag and significant photometric measurements somewhat fainter. Galaxy catalogs selected in the {R} and K_s_ bands are presented, containing 3607 and 488 sources in field areas of 74.8 and 59.4arcmin^2^, to {R}=25.5 and K_s_=20mag.
- ID:
- ivo://CDS.VizieR/J/A+A/563/A142
- Title:
- UGR photometry of LBG candidates at z~3
- Short Name:
- J/A+A/563/A142
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep multi wavelength imaging survey (UGR) in 3 different fields, Q0933, Q1623 and COSMOS, for a total area of ~1500arcmin^2^ The data were obtained with the Large Binocular Camera on the Large Binocular Telescope. To select our LBG candidates we adopt the well established and widely used color selection criterion (U-G vs. G-R). One of the main advantages of our survey is that it has a wider dynamic color range for U drop-out selection compared to previous studies. This allows us to fully exploit the depth of our R band images, obtaining a robust sample with few interlopers. In addition, for 2 of our fields we have spectroscopic redshift information that is necessary to better estimate the completeness of our sample and interloper fraction. Our limiting magnitudes reach 27.0(AB) in the R band (5{sigma}) and 28.6(AB) in the U band (1{sigma}). This dataset was used to derive Lyman Break Galaxy candidates at z~3. We obtained a catalog with a total of 12264 sources down to the 50% completeness magnitude limit in the R band for each field. We find a surface density of ~3 LBG candidates arcmin^-2^ down to R=25.5, where completeness is >=95% for all 3 fields. This number is higher than the original studies, but consistent with more recent samples.
7358. UGSs. V. kernel approach
- ID:
- ivo://CDS.VizieR/J/ApJS/209/10
- Title:
- UGSs. V. kernel approach
- Short Name:
- J/ApJS/209/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nearly one-third of the {gamma}-ray sources detected by Fermi are still unidentified, despite significant recent progress in this area. However, all of the {gamma}-ray extragalactic sources associated in the second Fermi-LAT catalog have a radio counterpart. Motivated by this observational evidence, we investigate all the radio sources of the major radio surveys that lie within the positional uncertainty region of the unidentified {gamma}-ray sources (UGSs) at a 95% level of confidence. First, we search for their infrared counterparts in the all-sky survey performed by the Wide-field Infrared Survey Explorer (WISE) and then we analyze their IR colors in comparison with those of the known {gamma}-ray blazars. We propose a new approach, on the basis of a two-dimensional kernel density estimation technique in the single [3.4]-[4.6]-[12]{mu}m WISE color-color plot, replacing the constraint imposed in our previous investigations on the detection at 22{mu}m of each potential IR counterpart of the UGSs with associated radio emission. The main goal of this analysis is to find distant {gamma}-ray blazar candidates that, being too faint at 22{mu}m, are not detected by WISE and thus are not selected by our purely IR-based methods. We find 55 UGSs that likely correspond to radio sources with blazar-like IR signatures. An additional 11 UGSs that have blazar-like IR colors have been found within the sample of sources found with deep recent Australia Telescope Compact Array observations.
- ID:
- ivo://CDS.VizieR/J/ApJS/104/287
- Title:
- UIT near-UV bright objects catalog
- Short Name:
- J/ApJS/104/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric catalog of 2244 objects detected by the Ultraviolet Imaging Telescope in the near-ultraviolet (NUV; 1650A<lambda<2900A) during the Astro-1 Space Shuttle mission. Sources in the catalog are as faint as m_nuv~18.8, or f_nuv~1.1x10^-16ergs/s/cm^2/A, but the survey is not complete to this level. Optical catalogs were used to cross identify sources and derive NUV-V colors. A majority of the objects (88%) do indeed have proposed optical identifications from catalogs, and most are stars. Our purpose in creating the catalog is to form a database useful for identifying very blue objects and performing Galactic UV stellar population studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/341/993
- Title:
- u_j_br photometry and redshifts of QSOs
- Short Name:
- J/MNRAS/341/993
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed analysis of a sample of radio-detected quasars, obtained by matching together objects from the FIRST (<VIII/71>) survey and the 2dF Quasar Redshift Survey (2dF, <VII/223>). The data set consists of 113 sources, spanning a redshift range 0.35<~z<~2.2, with optical magnitudes 18.25<=bj<=20.85 and radio fluxes S_1.4GHz_>=1mJy. These objects exhibit properties such as redshift and colour distribution in full agreement with those derived for the whole quasar population, suggesting that the mechanism(s) controlling the birth and lifetime of quasars are independent of their level of radio emission. The long-debated question of the radio-loud/radio quiet (RL/RQ) dichotomy is then investigated for the combined FIRST-2dF and FIRST-LBQS (Large Bright Quasar Survey) samples, as they present similar selection criteria.
