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691. W49N H2O maser outflow: distance and kinematics
ID:
ivo://CDS.VizieR/J/ApJ/393/149
Title:
W49N H2O maser outflow: distance and kinematics
Short Name:
J/ApJ/393/149
Date:
21 Oct 2021
Publisher:
CDS
Description:
Study of the motions of 105 H2O maser features clustered around a newly formed star in W49N yields the kinematics of the gas flow, the distance to the source, and the spatial scale of the Milky Way. We find that the maser outflow is bipolar, with an opening angle of ~60deg and an inclination of ~40deg to the line of sight. The expansion has a constant velocity of ~18 km/s out to a radius of 0.1pc, beyond which the outflow velocity increases to greater than 200 km/s. This increase may be due to interaction with ambient material. A rotation is also present; this rotation is nearly perpendicular to the outflow axis. The rotation may be due to ram pressure from ambient material; rotation of the ring of H II regions described by Welch et al. could produce such nonradial motion. Comparison of Doppler velocities and proper motions yields a distance of 11.4+/-1.2 kpc for the maser cluster. Combining this with a kinematic distance for W49N from Galactic rotation, we obtain a value of R0, the distance to the Galactic center, of 8.1+/-1.1 kpc.
692. XC1 catalogue of positions and proper motions
ID:
ivo://CDS.VizieR/I/302
Title:
XC1 catalogue of positions and proper motions
Short Name:
I/302
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the astrometric catalogue of faint reference stars in 255deg^2^ sized fields with ICRF objects of northern hemisphere. The XC1 is based on our results of measurements and astrometric reduction of digitized images of Schmidt plates POSS-I and POSS-II sky surveys obtained from USNOFS PMM Image Archive. The Tycho-2 (Cat. <I/259>) catalogue was used as a reference catalogue for astrometric reductions. The mean positions and proper motions of stars were derived from their individual positions at the different epochs. For some stars the 2MASS (Cat. <II/246>) positions were used also. The limiting magnitude is about V=19mag. The estimated external errors are 50-150mas in positions at mean epoch, and 2-5mas/yr in proper motions, depending on magnitude. The catalog is present as a set of individual fields in separate files. The name of each file is the ERS designation of corresponding ICRF radio source.
693. XMM observations of the Lockman Hole
ID:
ivo://CDS.VizieR/J/A+A/479/283
Title:
XMM observations of the Lockman Hole
Short Name:
J/A+A/479/283
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Lockman Hole represents the sky area of lowest Galactic line-of-sight columns density. It was observed by the XMM-Newton X-ray observatory in 18 pointings performed between April 2000 and December 2002. The total exposure time spent on the field was 1.16Ms (EPIC pn detector; EPIC MOS detector: 1.30 Ms). The effective exposure after removal of times of high particle background is 637ks (EPIC pn detector; EPIC MOS detector: 765ks). The catalogue lists positions, count rates, fluxes, hardness ratios, and partial optical classifications of 409 X-ray point sources detected in the central 0.196{deg}2 of the field down to a detection likelihood threshold of 10 (3.9sigma). The analysis was performed using the XMM-Newton SAS data analysis package version 6.0.
694. XPM Catalog of positions and proper motions
ID:
ivo://CDS.VizieR/I/319
Title:
XPM Catalog of positions and proper motions
Short Name:
I/319
Date:
21 Oct 2021
Publisher:
CDS
Description:
We combined data from the Two-Micron All Sky Survey (2MASS) and USNO-A2.0 catalogues in order to derive the absolute proper motions of about 280 million stars distributed all over the sky excluding a small region near the Galactic Centre, in the magnitude range 12<B<19mag. The proper motions were derived from the 2MASS Point Sources and USNO-A2.0 catalogue positions with a mean epoch difference of about 45 years for the Northern hemisphere and about 17 years for the Southern one. The zero-point of the absolute proper motion frame (the 'absolute calibration') was specified with the use of about 1.45 million galaxies from 2MASS. Most of the systematic zonal errors inherent in the USNO-A2.0 catalogue were eliminated before the calculation of proper motions. The mean formal error of absolute calibration is less than 1mas/yr.
695. 126 X-rays sources around the cepheid {eta} Aql
ID:
ivo://CDS.VizieR/J/AJ/162/92
Title:
126 X-rays sources around the cepheid {eta} Aql
Short Name:
J/AJ/162/92
Date:
14 Mar 2022 07:02:20
Publisher:
CDS
Description:
X-ray bursts have recently been discovered in the Cepheids {delta}Cep and {beta}Dor modulated by the pulsation cycle. We have obtained an observation of the Cepheid {eta}Aql with the XMM-Newton satellite at the phase of maximum radius; the phase at which there is a burst of X-rays in {delta}Cep. No X-rays were seen from the Cepheid {eta}Aql at this phase, and the implications for Cepheid upper atmospheres are discussed. We have also used the combination of X-ray sources, as well as Gaia and 2MASS data, to search for a possible grouping around the young intermediate mass Cepheid. No indication of such a group was found.
696. XZ Catalog of Zodiacal Stars (XZ80N)
ID:
ivo://CDS.VizieR/I/201
Title:
XZ Catalog of Zodiacal Stars (XZ80N)
Short Name:
I/201
Date:
21 Oct 2021
Publisher:
CDS
Description:
The XZ catalog was created at the U.S. Naval Observatory in 1977 by Richard Schmidt and Tom Van Flandern, primarily for the purpose of generating predictions of lunar occultations, and for analyzing timings of these events. It was designed to include all stars from Robertson's Zodiacal Catalog (ZC), the SAO catalog, and the AGK3 catalog that are within 6d 40' of the ecliptic (a region hereafter called "the Zodiac"), which is as far as the Moon's limb can ever get as seen from anywhere on the Earth's surface, leaving some margin for stellar proper motions and change in the obliquity of the ecliptic over the course of three centuries. The original version contained 32,221 entries. Since that time, a number of changes have been made in succeeding versions, including better positions and proper motions, and the elimination and addition of stars. The catalog contains visual magnitudes and radial velocities as well as astrometric data. Two years after the catalog was created, and observations were already reported using its numbers, it was found that about 200 stars near the equator from the AGK3 catalog were outside the Zodiac, and a similar number that should have been included were not. Since the numbering system had already been established, the catalog was not changed to correct this deficiency. Over the years, some errors in the catalog, due mainly to errors in the SAO and AGK3, were corrected. A few stars with very bad data were "eliminated" by changing their declination to -89d and adding 40 to their magnitudes. In 1986, most of the stellar positional data were replaced with improved data from Harrington's and Douglass' Zodical Zone (ZZ) catalog, which used for its observing list SAO stars in the Zodiac (actually broader than the XZ Zodiac because ecliptic latitudes to +/-15d were used) north of declination approximately -25d. The positional data for many of the stars south of declination -25d with right ascensions greater than 18h were improved with data from the Lick Voyager Uranus catalog. In 1991, the photographic magnitudes of the AGK3 stars not in the SAO were converted to photovisual magnitudes by applying corrections based on each star's spectral type, when available. Stellar magnitudes and double-star codes have been updated periodically based on reports from observers. Each time a series of updates was made, the XZ version was changed. The current version is XZ80N, created during the summer of 1992. Late in the summer of 1992, Mitsuru Soma in Japan created a J2000 version of the XZ, which we call XZ80NJ2. The next update is planned for 1994, when the positional data may also be replaced with PPM data; probably only the J2000 version will be updated. The XZ catalog is no longer maintained at the U.S. Naval Observatory (USNO); it is now maintained by the International Occultation Timing Association (IOTA). The changes made to the different versions of the XZ catalog during the past several years have been documented in Occultation Newsletter, IOTA's quarterly publication.
697. XZ Catalog of Zodiacal Stars (XZ80Q)
ID:
ivo://CDS.VizieR/I/291
Title:
XZ Catalog of Zodiacal Stars (XZ80Q)
Short Name:
I/291
Date:
21 Oct 2021
Publisher:
CDS
Description:
The XZ catalog was created at the U.S. Naval Observatory in 1977 by Richard Schmidt and Tom Van Flandern, primarily for the purpose of generating predictions of lunar occultations, and for analyzing timings of these events. It was designed to include all stars within 6d 40' of the ecliptic (the "Zodiac"), which is as far as the Moon's limb can ever get as seen from anywhere on the Earth's surface, leaving some margin for stellar proper motions and change in the obliquity of the ecliptic over the course of three centuries. The original version contained 32,221 entries; since that time, many changes have been made in succeeding versions, including better positions and proper motions, and the elimination and addition of stars. Details about the history of XZ catalog can be found in the "doc.txt" file. The XZ80Q revision has been developed from XZ80P, which was created by Mitsuru Soma. It is now complete over the Zodiac for stars down to visual magnitude 12.0. The "xz80q.dat" file contains the list of stars making the catalog; additional files provide details about double and variable stars included in the XZ80Q. The catalog includes also lists of the various existing names of the stars.
698. Yale/San Juan SPM4 Catalog
ID:
ivo://org.gavo.dc/spm4/q/cone
Title:
Yale/San Juan SPM4 Catalog
Short Name:
SPM4 CS
Date:
27 Dec 2024 08:31:02
Publisher:
The GAVO DC team
Description:
The SPM4 Catalog contains absolute proper motions, celestial coordinates, and B,V photometry for 103,319,647 stars and galaxies between the south celestial pole and -20 degrees declination. The catalog is roughly complete to V=17.5. It is based on photographic and CCD observations taken with the Yale Southern Observatory's double-astrograph at Cesco Observatory in El Leoncito, Argentina.
699. Yale Zone Catalogues Integrated
ID:
ivo://CDS.VizieR/I/141
Title:
Yale Zone Catalogues Integrated
Short Name:
I/141
Date:
21 Oct 2021
Publisher:
CDS
Description:
The various volumes of the Yale Zone Catalogues have been combined into a single, homogeneous, machine-readable volume, sorted by position, containing the information common to most of the volumes. Additional data are provided in separate files. The notes have been transcribed into a machine-readable form. Errors detected in the course of the preparation of the catalogue, as well as previously known errors, have been corrected, and supplementary data have been added.
700. 20 years of photometric microlensing
ID:
ivo://CDS.VizieR/J/A+A/617/A135
Title:
20 years of photometric microlensing
Short Name:
J/A+A/617/A135
Date:
21 Oct 2021
Publisher:
CDS
Description:
Gaia DR2 offers unparalleled precision on stars' parallaxes and proper motions. This allows the prediction of microlensing events for which the lens stars (and any planets they possess) are nearby and may be well studied and characterised. We identify a number of potential microlensing events that will occur before the year 2035.5, 20 years from the Gaia DR2 reference epoch. We query Gaia DR2 for potential lenses within 100pc, extract parallaxes and proper motions of the lenses and background sources, and identify potential lensing events. We estimate the lens masses from Priam effective temperatures, and use these to calculate peak magnifications and the size of the Einstein radii relative to the lens stars' habitable zones. We identify 7 future events with a probability >10% of an alignment within one Einstein radius. Of particular interest is DR2 5918299904067162240 (WISE J175839.20-583931.6), magnitude G=14.9, which will lens a G=13.9 background star in early 2030, with a median 23% net magnification. Other pairs are typically fainter, hampering characterisation of the lens (if the lens is faint) or the ability to accurately measure the magnification (if the source is much fainter than the lens). Of timely interest is DR2 4116504399886241792 (2MASS J17392440-2327071), which will lens a background star in July 2020, albeit with weak net magnification (0.03%). Median magnifications for the other 5 high-probability events range from 0.3% to 5.3%. The Einstein radii for these lenses are 1-10 times the radius of the habitable zone, allowing these lensing events to pick out cold planets around the ice line, and filling a gap between transit and current microlensing detections of planets around very low-mass stars. We provide a catalogue of the predicted events to aid future characterisation efforts. Current limitations include a lack of many high-proper motion objects in Gaia DR2 and often large uncertainties on the proper motions of the background sources (or only 2-parameter solutions). Both of these deficiencies will be rectified with Gaia DR3 in 2020. Further characterisation of the lenses is also warranted to better constrain their masses and predict the photometric magnifications.

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