Number of results to display per page
Search Results
19002. The North 20cm Survey
- ID:
- ivo://CDS.VizieR/VIII/17
- Title:
- The North 20cm Survey
- Short Name:
- VIII/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a list of 30239 radio sources at 1.4GHz over the declination range of -5 to +82 degrees. This catalog is based on the Green Bank 1.4GHz Northern Sky Survey (Condon and Broderick, 1986, Cat. VIII/6) which was generated using the Green Bank 300 foot (91m) telescope. The threshold for identifying a 1.4GHz radio source was set at 100mJy. The catalog data include the source name, a confusion flag, right ascension (1950), declination (1950), 1.4GHz flux, a flag to indicate if the source is extended at 20cm, 4.85GHz flux (from Becker et al., 1991, Cat. VIII/13), a flag to indicate if the source is extended at 6cm, 365MHz flux (from the Texas Survey, Douglas et al. 1980; see Cat. VIII/42)), spectral index between 6 and 20 cm, and spectral index between 20 and 80 cm. Where possible, the source name is derived from the 6cm catalog of Becker et al. 1991 (Cat. VIII/13).
19003. The nuclei of 3 comets
- ID:
- ivo://CDS.VizieR/J/A+A/444/287
- Title:
- The nuclei of 3 comets
- Short Name:
- J/A+A/444/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Jupiter Family comets (JFCs) are short period comets which have recently entered the inner solar system, having previously orbited in the Kuiper Belt since the formation of the planets. We used two nights on the 3.6 m New Technology Telescope (NTT) at the European Southern Observatory, to obtain VRI photometry of three JFCs; 7P/Pons-Winnecke, 14P/Wolf and 92P/Sanguin. These were observed to be stellar in appearance.
19004. The OB association LH 58
- ID:
- ivo://CDS.VizieR/J/AJ/108/1256
- Title:
- The OB association LH 58
- Short Name:
- J/AJ/108/1256
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD photometry and spectroscopy for stars in Lucke-Hodge 58, an isolated OB association in the Large Magellanic Cloud (LMC) northwest of 30 Doradus. The photometric catalog contains 839 stars with UBV magnitudes complete to V~19. We have obtained spectra and classified 35 stars; combined with previous published spectral types, we find 22 O-type stars. The earliest type is O3-4 V, and there are three WR stars in the association. The slope of the initial mass function, Gamma=-1.7+/-0.3, is in good agreement with other LMC associations. The presence of several evolved supergiants with masses about 15-25M_{sun}_ suggests that some star formation took place as early as 10 million years ago, but the majority of stars formed coevally within the past few million years.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/14
- Title:
- The Ogle et al. Galaxy Catalog (OGC)
- Short Name:
- J/ApJS/243/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of the 1525 most optically luminous galaxies from the Sloan Digital Sky Survey with r-band luminosity L_r_>8L* and redshift z<0.3, including 84 super spirals, 15 super lenticulars, 14 super post-merger galaxies, and 1400 giant ellipticals. With mass in stars of 10^11.3^-10^12^M_{sun}_, super spirals and lenticulars are the most massive disk galaxies currently known. The specific star formation rates of super spirals place them on or below the star-forming main sequence. They must have formed stars at a high rate throughout their history in order to grow their massive, gigantic stellar disks and maintain their blue u-r integrated colors. Their disks are red on the inside and blue on the outside, consistent with inside-out growth. They tend to have small bulge-to-total (B/T) r-band luminosity ratios, characteristic of disk building via minor mergers and cold accretion. A large percentage of super disk galaxies (41%) have double nuclei, double disks, or other signatures of ongoing mergers. Most (72%) are found in moderate- to low-density environments, while the rest are found at the outskirts of clusters. It is likely that super spirals survive in these environments because they continue to accrete cold gas and experience only minor mergers at late times, by virtue of their enormous masses and angular momenta. We suggest that super post-mergers are the product of super spiral major mergers and may be the precursors of some giant elliptical galaxies found in low-density environments.
- ID:
- ivo://CDS.VizieR/J/ApJ/737/71
- Title:
- The [OIII] emission line in SDSS AGNs
- Short Name:
- J/ApJ/737/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use homogeneous samples of radio-quiet Seyfert 1 galaxies and QSOs selected from the Sloan Digital Sky Survey to investigate the connection between the velocity shift and the equivalent width (EW) of the [OIII]{lambda}5007 emission line, and their correlations with physical parameters of active galactic nuclei (AGNs). We find a significant and negative correlation between the EW of the core component, EW(core), and the blueshift of either the core (the peak), the wing, or the total profile of [OIII] emission; it is fairly strong for the blueshift of the total profile in particular. However, both quantities (EW and velocity shift) generally have only weak, if any, correlations with fundamental AGN parameters such as the nuclear continuum luminosity at 5100{AA} (L_5100_), black hole mass (M_BH_), and the Eddington ratio (L/L_Edd_); these correlations include the classical Baldwin effect of EW(core), an inverse Baldwin effect of EW(wing), and the relationship between velocity shifts and L/L_Edd_. Our findings suggest that both the large object-to-object variation in the strength of [OIII] emission and the blueshift-EW(core) connection are not governed primarily by fundamental AGN parameters such as L_5100_, M_BH_, and L/L_Edd_. We propose that the interstellar medium conditions of the host galaxies play a major role instead in the diversity of the [OIII] properties in active galaxies. This suggests that the use of [OIII]{lambda}5007 luminosity as a proxy of AGN luminosity does not depend strongly on the above-mentioned fundamental AGN parameters.
19007. The open cluster NGC 346
- ID:
- ivo://CDS.VizieR/J/PASP/98/1133
- Title:
- The open cluster NGC 346
- Short Name:
- J/PASP/98/1133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD photometry and spectrographic observations for stars in the open cluster NGC 346, which excites the largest H II region in the Small Magellanic Cloud. These observations show that NGC 346 is an extremely young cluster, containing more than 20 hot O-type stars. A radial-velocity study of the brightest stars, and also of the nearby supergiant Of star Sk 80, discloses atmospheric expansion due to strong stellar winds, but no large-amplitude radial-velocity variations due to short-period binary motion. However, two stars are probably longer period binaries.
- ID:
- ivo://CDS.VizieR/J/A+AS/139/135
- Title:
- The Optical Spectrum of RR Tel
- Short Name:
- J/A+AS/139/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The symbiotic nova RR Telescopii has been observed with the 3.9 m telescope at the Anglo-Australian Observatory (AAO), using the University College London Echelle Spectrograph (UCLES) in conjunction with a Tek CCD. It displays a rich emission line spectrum, ranging in excitation from NI to NiVIII. We present a list of 811 measured lines, with their suggested identifications and absolute line intensities, covering a wavelength range from 3180 to 9455 A. The absolute line intensities have been derived by comparing the high resolution data with a flux-calibrated low resolution spectrum taken with the Australian National University 2.3 m telescope. All of the lines have been successfully identified. Comparing our results with those of previous studies indicates that the RR Tel system is advancing towards higher degrees of ionisation.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/1
- Title:
- The OPTX project: CLANS, CLASXS and CDF-N
- Short Name:
- J/ApJS/179/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the redshift catalogs for the X-ray sources detected in the Chandra Deep Field-North (CDF-N), the Chandra Large Area Synoptic X-ray Survey (CLASXS), and the Chandra Lockman Area North Survey (CLANS). The catalogs for the CDF-N and CLASXS fields include redshifts from previous work, while the redshifts for the CLANS field are all new. For fluxes above 10^-14^ergs/cm^2^/s (2-8keV) we have redshifts for 76% of the sources. We extend the redshift information for the full sample using photometric redshifts. The goal of the OPTX Project is to use these three surveys, which are among the most spectroscopically complete surveys to date, to analyze the effect of spectral type on the shape and evolution of the X-ray luminosity functions and to compare the optical spectral types with the X-ray spectral properties. We also present the CLANS X-ray catalog. The nine ACIS-I fields cover a solid angle of ~0.6deg^2^ and reach fluxes of 7x10^-16^ergs/cm^2^/s (0.5-2keV) and 3.5x10^-15^ergs/cm^2^/s (2-8keV). We find a total of 761 X-ray point sources. In addition, we present the optical and infrared photometric catalog for the CLANS X-ray sources, as well as updated optical and infrared photometric catalogs for the X-ray sources in the CLASXS and CDF-N fields.
19010. The OPTX project. III.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/2160
- Title:
- The OPTX project. III.
- Short Name:
- J/ApJ/703/2160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the optical spectral types with the X-ray spectral properties for a uniformly selected (sources with fluxes greater than the 3{sigma} level and above a flux limit of f(2-8keV)>3.5x10^-15^erg/cm^2^/s), highly spectroscopically complete (>80% for f(2-8keV)>10^-14^erg/cm^2^/s and >60% below) 2-8keV X-ray sample observed in three Chandra fields (CLANS, CLASXS, and the CDF-N) that cover ~1.2deg^2^. For our sample of 645 spectroscopically observed sources, we confirm that there is significant overlap of the X-ray spectral properties, as determined by the effective photon indices, {Gamma}_eff_, obtained from the ratios of the 0.5-2keV to 2-8keV counts, for the different optical spectral types. Thus, one cannot use the X-ray spectral classifications and the optical spectral classifications equivalently. Since it is not understood how X-ray and optical classifications relate to the obscuration of the central engine, we strongly advise against a mixed classification scheme, as it can only complicate the interpretation of X-ray AGN samples.