In this paper we report on the third soft gamma-ray source catalog obtained with the IBIS/ISGRI gamma-ray imager on board the INTEGRAL satellite. The scientific data set is based on more than 40Ms of high-quality observations performed during the first 3.5yr of Core Program and public IBIS/ISGRI observations. Compared to previous IBIS/ISGRI surveys, this catalog includes a substantially increased coverage of extragalactic fields, and comprises more than 400 high-energy sources detected in the energy range 17-100keV, including both transients and faint persistent objects that can only be revealed with longer exposure times.
On the basis of the data observed with the Photoelectric Transit Instrument, of the Beijing Astronomical Observatory during the period from 1980 through 1984, the third preliminary catalogue of stars on right ascension observed with the Photoelectric Transit Instrument (PPCP3) have been compiled. The relations between the residuals V and the magnitude M, and the spectral type S of FK4 stars are discussed. There are 411 stars in this catalogue. The mean precisions of {DELTA}alpha's is +/-2.3ms. Finally systematic corrections of PPCP3-FK4 are given.
The University of Texas has revised its third edition of its catalogue of bright galaxies. This not only contains many more entries than the second edition (23,022) but substantially more information for each entry.
We present the third extension to the Very Long Baseline Array (VLBA) Calibrator Survey, containing 360 new sources not previously observed with Very Long Baseline Interferometry (VLBI). The survey, based on three 24 hour VLBA observing sessions, fills the areas on the sky above declination -45{deg} where the calibrator density is less than one source within a 4{deg} radius disk at any given direction. The positions were derived from astrometric analysis of the group delays determined at 2.3 and 8.6GHz frequency bands using the CALC/SOLVE software package. The VCS3 catalog of source positions, plots of correlated flux density versus length of projected baseline, and contour plots and FITS files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available electronically from the Goddard Geodetic VLBI Group.
We present the next regular Name-List of variable stars containing information on 1706 variable stars recently designated in the system of the General Catalogue of Variable Stars.
We present the special Name-List of variable stars containing information on 1270 variable stars recently designated in the system of the General Catalogue of Variable Stars, which are mostly former suspected variables from the NSV catalogue.
We present the first part of a new Name-List of variable stars containing information on 1951 variable stars recently designated in the system of the General Catalogue of Variable Stars. With the exception of Novae and other unusual variables named upon request from the IAU CBAT or by our initiative, these stars are in the range of J2000.0 right ascensions from 0 hours to 17 hours 30 minutes.
We present the first part of a new Name-List of variable stars containing information on 2036 variable stars recently designated in the system of the General Catalogue of Variable Stars. With the exception of unusual variables named upon request from the IAU CBAT, these stars are in the range of J2000.0 right ascensions from 0 to 6 hours.
We present the second part of a new Name-List of variable stars containing information on 2090 variable stars recently designated in the system of the General Catalogue of Variable Stars. All these stars are in the range of J2000.0 right ascensions from 17 hours 30 minutes to 24 hours.
The Galactic plane has been observed extensively by a large number of Galactic plane surveys from infrared to radio wavelengths at an angular resolution below 40". However, a 21cm line and continuum survey with comparable spatial resolution is lacking. The first half of THOR data (l=14.0{deg}-37.9{deg}, and l=47.1{deg}-51.2{deg}, |b|<=1.25{deg}) has been published in our data release 1 paper. With this data release 2 paper, we publish all the remaining spectral line data and Stokes I continuum data with high angular resolution (10"-40"), including a new HI dataset for the whole THOR survey region (l=14.0{deg}-67.4{deg} and |b|<=1.25{deg}). As we published the results of OH lines and continuum emission elsewhere, we concentrate on the HI analysis in this paper With the Karl G. Jansky Very Large Array (VLA) in C-configuration, we observed a large portion of the first Galactic quadrant, achieving an angular resolution of 40". At L Band, the WIDAR correlator at the VLA was set to cover the 21cm HI line, four OH transitions, a series of Hn{alpha} radio recombination lines (RRLs; n=151 to 186), and eight 128MHz-wide continuum spectral windows (SPWs), simultaneously. We publish all OH and RRL data from the C-configuration observations, and a new HI dataset combining VLA C+D+GBT (VLA D-configuration and GBT data are from the VLA Galactic Plane Survey) for the whole survey. The HI emission shows clear filamentary substructures at negative velocities with low velocity crowding. The emission at positive velocities is more smeared-out, likely due to higher spatial and velocity crowding of structures at the positive velocities. Compared to the spiral arm model of the Milky Way, the atomic gas follows the Sagittarius and Perseus Arm well, but with significant material in the inter-arm regions. With the C-configuration-only HI+continuum data, we produced a HI optical depth map of the THOR areal coverage from 228 absorption spectra with the nearest-neighbor method. With this map, we corrected the HI emission for optical depth, and the derived column density is 38% higher than the column density with optically thin assumption. The total HI mass with optical depth correction in the survey region is 4.7x10^8^M_{sun}_, 31% more than the mass derived assuming the emission is optically thin. If we applied this 31% correction to the whole Milky Way, the total atomic gas mass would be 9.4-10.5x10^9^M_{sun}_. Comparing the HI with existing CO data, we find a significant increase in the atomic-to-molecular gas ratio from the spiral arms to the inter-arm regions. The high-sensitivity and resolution THOR HI dataset provides an important new window on the physical and kinematic properties of gas in the inner Galaxy. Although the optical depth we derive is a lower limit, our study shows that the optical depth correction is significant for Hi column density and mass estimation. Together with the OH, RRL and continuum emission from the THOR survey, these new HI data provide the basis for high-angular-resolution studies of the interstellar medium (ISM) in different phases.