This service publishes spectral matrix data from the Earth magnetosphere
obtained by the THEMIS satellites. The data contains the upper
triangle for the 6x6 correlation matrix of the three magnetic and
three electric components of the electromagnetic field in 164 frequency
bands in the magnetic field-aligned reference frame. For more information, refer
to https://doi.org/10.1007/s10712-018-9503-1
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.
We present a new list of thorium and argon emission lines in the visible obtained by analyzing high-resolution (R=110000) spectra of a ThAr hollow cathode lamp. The aim of this new line list is to allow significant improvements in the quality of wavelength calibration for medium- to high-resolution astronomical spectrographs. We use a series of ThAr lamp exposures obtained with the HARPS instrument (High Accuracy Radial-velocity Planet Searcher) to detect previously unknown lines, perform a systematic search for blended lines and correct individual wavelengths by determining the systematic offset of each line relative to the average wavelength solution.
The solar telescope connected to HARPS-N has observed the Sun since the summer of 2015. Such high-cadence, longbaseline data set is crucial for understanding spurious radial-velocity signals induced by our Sun and by the instrument. Aims. This manuscript describes the data reduction performed to obtain unprecedented radial-velocity precision for the three years of solar data released along with this paper. The nearly continuous observation of our Sun has allowed us to detect sub-m/s systematics in the HARPS-N solar data reduced by the current data reduction software. To improve the radial-velocity precision of the solar data, we reduced them using the new ESPRESSO data reduction software and developed new recipes to mitigate the detected systematics. The most significant improvement brought by the new data reduction is a strong decrease in the day-to-day radial-velocity scatter, from 1.28 to 1.09m/s; this is thanks to a more stable method to derive wavelength solutions, but also to the use of calibrations closer in time. We also demonstrate that the current HARPS-N data reduction software induces a long-term drift of 1.2m/s, due to the use of non-stable thorium lines. As a result, the old solar RVs are weakly correlated to the solar magnetic cycle, which is not expected. On the contrary, the newly derived radial velocities are much more correlated, with a Pearson correlation coefficient of 0.93. We also discuss a special correction for ghost contamination, to extract a calcium activity index free from instrumental systematics. Our work leads toward a better understanding of the instrumental and data reduction systematics affecting the HARPSN spectrograph. The new solar data released, representing an unprecedented time-series of 34550 high-resolution spectra and precise radial velocities will be crucial to understanding stellar activity signals of solar-type stars, with the goal of enabling the detection of other Earths.
We have made precise observations of a thorium-argon hollow cathode lamp emission spectrum in the region between 350nm and 1175nm using a high-resolution Fourier transform spectrometer. Our measurements are combined with results from seven previously published thorium line lists to re-optimize the energy levels of neutral, singly, and doubly ionized thorium (Th I, Th II, and Th III). Using the optimized level values, we calculate accurate Ritz wavelengths for 19874 thorium lines between 250nm and 5500nm (40000/cm to 1800/cm). We have also found 102 new thorium energy levels. A systematic analysis of previous measurements in light of our new results allows us to identify and propose corrections for systematic errors in Palmer & Engleman (1983ats..book.....P) and typographical errors and incorrect classifications in Kerber et al. (2008ApJS..178..374K). We also found a large scatter with respect to the thorium line list of Lovis & Pepe (Cat. J/A+A/468/1115). We anticipate that our Ritz wavelengths will lead to improved measurement accuracy for current and future spectrographs that make use of thorium-argon or thorium-neon lamps as calibration standards.
