The ASCAMASTER table contains data on all ASCA observations that were ever in any of the following states: 'Accepted', 'Scheduled Long-Term', 'Scheduled Short-Term', 'Processed', and 'Archived'. The final status of an observation is given by the parameter Status. Specific dates that affect the status of an observation are listed as the parameters scheduled_date, observed_date, processed_date, archived_date, and cycle. Notice that, if one or more of the date parameters are empty for a given observation, this means that that those particular processes have not occurred: e.g., if observed_date is empty, this means that the planned observation was not observed. This is a service provided by NASA HEASARC .
The ASCAPRSPEC table was created for the purpose of providing a complete, accurate, and easily accessible tracking of ASCA proposal information. This is a service provided by NASA HEASARC .
The ASCAO database contains the listing of accepted targets from all proposals submitted in repsonse to the ASCA Guest Observer (GO) Announcements of Opportunities (AOs), as well as the targets that were selected for the Performance Verification (PV) phase. The current version of ASCAO includes all accepted targets from AOs 1 through 8.5 inclusive. Notice that, since the accepted targets include Priority 3 ones of which only a fraction have or will actually be observed, some of the listed targets in this database will never have been observed. To obtain more detailed information about the status of particular targets, please consult either the Master ASCA database table (ASCAMASTER) or the ASCA Observing Log database table (ASCALOG). This database was last updated in August 2000 based on information provided by the ASCA Project. This is a service provided by NASA HEASARC .
This preliminary ASCA SIS Source Catalog contains a list of point sources detected by the Solid-state Imaging Spectrometers (SIS) on-board the ASCA Observatory. This catalog was generated by searching for point-like sources in all data available from the HEASARC's ASCA public archive (ASCAPUBLIC) as of 24 Oct 1996; and is populated by both target and serendipitous sources in the SIS field-of-view. For each catalogued source various information is available, which includes the celestial coordinates of the source, the count rate, the significance of detection, and the hardness ratio, total aperture counts, exposure time, and start time of the observation. In addition, a set of three GIF "thumbnail" images is available in the broad (0.5 - 12 keV), soft (2 < keV), and hard (> 2 keV) spectral bands centered on the apparent detection. These images are convenient for accessing the quality of the source detection. The current catalog is preliminary, the goal of the catalog authors being to make the SIS source list available as quickly as possible. To accomplish this, they took an incremental approach and placed their "work in progress" on-line, warts and all. They urge caution in using and citing these preliminary results, as they point out that the information is not, as yet, 100% reliable. This catalog was generated in January 1997 by Drs. Eric Gotthelf and Nicholas White and resulted from their search for point-like sources in all of the then-available SIS data files in the HEASARC's Public ASCA Data Archive as of 24 Oct 1996. The catalog is populated with both targeted and serendipitous sources that were present in the SIS field-of-view. This is a service provided by NASA HEASARC .
We made 22 observations on the Small Magellanic Cloud (SMC) and covered full regions of the main body and the eastern wing by the end of the ASCA mission. We detected 106 discrete sources with a criterion of S/N>5 and performed systematic analyses on all of the sources. We determined the source positions with an ~40" error radius (90% confidence) for sources detected in the central 20' radius of the GIS. We detected coherent pulsations from 17 sources. Among them, eight were newly discovered during this study. We classified most of these pulsars as X-ray binary pulsars (XBPs) based on their properties, such as the flux variability and the existence of an optical counterpart. We detected X-ray emission from eight supernova remnants (SNRs). Based on these ASCA results and further information from ROSAT, SAX, RXTE, CGRO, Chandra, and XMM-Newton, we compiled comprehensive catalogues of discrete X-ray sources in the Small Magellanic Cloud.
The ASC is a compilation produced for the Gaia mission. We have combined data from the following catalogs or datasets to produce a homogenous list of positions, proper motions, photometry in a blue and red band and estimates of the magnitudes in the Gaia G and G_RVS bands: Tycho2, UCAC4, Hipparcos, PPMXL, GSC2.3 and Sky2000. Originally ASC sources were selected from the Initial Gaia Source List (IGSL, <A HREF="http://cdsarc.u-strasbg.fr/cgi-bin/Cat?I/324">I/324</A>). However, here we produce a cleaner catalog starting from the bright source catalogs and using the following criteria: 1) The candidate must be in the Tycho2, UCAC4, Hipparcos or Sky2000 catalog. 2) The Gaia G magnitude must be brighter than 13.4. 3) The star must be isolated from other objects of similar magnitudes 4) The object must not be in the Washington Double Star catalog 5) If a healpix 6th region has more than 1000 objects the magnitude limit is reduced to reduce the number of objects in that region. Since the ASC was produced independently from the IGSL using different procedures there is not a direct 1 to 1 match between ASC and IGSL entries. We have matched the ASC to the IGSL and found that 9 out of the 8 million entries do not have a clear match. Since there may still remain ambiguous matches in the 8 million matched objects, we decided to assign the sourceIDs of the IGSL with the adjustment that the runningnumber is equal to the IGSL runningnumber + 320000. Included Catalogs: Tycho2, UCAC4, Sky2000, HIPPARCOS for candidates and the PPMXL, GSC2.3 were used to calculating magnitudes.
The first high-precision BVRI light curves of the eclipsing binary AS CrB were presented and were analyzed by the 2015 version of the W-D code. It is found that AS CrB is an extreme mass-ratio, deep contact binary with a fill-out factor of f=59.6+/-2.5% and a mass ratio of q=0.172+/-0.008q=0.172+/-0.008. Based on the photometric solution and the Dartmouth isochrones model, the masses, radii, and luminosities of the components are estimated as follows: M_1_=1.25+/-0.15M_{sun}_, M_1_=1.25+/-0.15M_{sun}_, M_2_=0.21+/-0.06M_{sun}_, M_2_=0.21+/-0.06M_{sun}_, R_1_=1.40+/-0.07R_{sun}_, R_1_=1.40+/-0.07R_{sun}_, R_2_=0.67+/-0.04R_{sun}_, R_2_=0.67+/-0.04R_{sun}_, L_1_=3.2+/-0.2L_{sun}_, L_1_=3.2+/-0.2L_{sun}_, and L_2_=0.72+/-0.04L_{sun}_, L_2_=0.72+/-0.04L_{sun}_, with an estimated distance 459+/-42pc. These uncertainties mainly come from the errors of the color used to estimate the temperature of the primary star. By investigating all of the available times of light minima, it is found that the Observed-Calculated [(O-C)(O-C)] curve shows a long-term period increase, with a rate of dP/dt=+(3.46+/-0.01)x10^-7^dP/dt=+(3.46+/-0.01)x10^-7^day/year. As an extreme mass-ratio contact binary, AS CrB may merge into a single star, such as an FK Com-type star or a blue straggler, because of the orbital instability.
In recent years, our understanding of giant planet formation progressed substantially. There have even been detections of a few young protoplanet candidates still embedded in the circumstellar disks of their host stars. The exact physics that describes the accretion of material from the circumstellar disk onto the suspected circumplanetary disk and eventually onto the young, forming planet is still an open question. We seek to detect and quantify observables related to accretion processes occurring locally in circumstellar disks, which could be attributed to young forming planets. We focus on objects known to host protoplanet candidates and/or disk structures thought to be the result of interactions with planets. We analyzed observations of six young stars and their surrounding environments with the SPHERE/ZIMPOL instrument on the Very Large Telescope (VLT) in the H{alpha} filter (656nm) and a nearby continuum filter (644.9nm). We redetect the known accreting M-star companion HD142527 B with the highest published signal to noise to date in both H{alpha} and the continuum. No other companions are detected. We analyzed observations of six young stars (age 3.5-10Myr) and their surrounding environments with the SPHERE/ZIMPOL instrument on the Very Large Telescope (VLT) in the H{alpha}filter (656nm) and a nearby continuum filter (644.9nm). We applied several point spread function (PSF) subtraction techniques to reach the highest possible contrast near the primary star, specifically investigating regions where forming companions were claimed or have been suggested based on observed disk morphology.
An automated search is applied to the Leiden/Dwingeloo HI Survey (LDS) for high-velocity clouds north of Dec.=-28{deg}. From the general catalog we extract a sample of relatively small (less than about 8{deg}) and isolated high-velocity clouds, CHVCs: anomalous-velocity HI clouds which are sharply bounded in angular extent with no kinematic or spatial connection to other HI features down to a limiting column density of 1.5x10^18cm^-2. Unambiguously isolated objects are given the "CHVC" designation, while those with some degree of ambiguity in this classification or designated "CHVC:" or "CHVC?". The vast majority of features show diffuse connections at low column densities with the extended HVC complexes and are simply designated as "HVC" features. The automated search algorithm has been applied to the HIPASS and to the Leiden/Dwingeloo data sets. The results from the LDS are described here; Putman et al. (2002, Cat. <J/AJ/123/873>) describe application of this algorithm to the HIPASS material. Only those catalog entries which have and additional ID listed have been confirmed in independent data.
Dual supermassive black holes (SMBHs) with kiloparsec-scale separations in merger-remnant galaxies are informative tracers of galaxy evolution, but the avenue for identifying them in large numbers for such studies is not yet clear. One promising approach is to target spectroscopic signatures of systems where both SMBHs are fueled as dual active galactic nuclei (AGNs), or where one SMBH is fueled as an offset AGN. Dual AGNs may produce double-peaked narrow AGN emission lines, while offset AGNs may produce single-peaked narrow AGN emission lines with line-of-sight velocity offsets relative to the host galaxy. We search for such dual and offset systems among 173 Type 2 AGNs at z<0.37 in the AGN and Galaxy Evolution Survey (AGES), and we find two double-peaked AGNs and five offset AGN candidates. When we compare these results to a similar search of the DEEP2 Galaxy Redshift Survey and match the two samples in color, absolute magnitude, and minimum velocity offset, we find that the fraction of AGNs that are dual SMBH candidates increases from z=0.25 to z=0.7 by a factor of ~6 (from 2/70 to 16/91, or 2.9_-1.9_^+3.6^% to 18_-5_^+5^%). This may be associated with the rise in the galaxy merger fraction over the same cosmic time. As further evidence for a link with galaxy mergers, the AGES offset and dual AGN candidates are tentatively ~3 times more likely than the overall AGN population to reside in a host galaxy that has a companion galaxy (from 16/173 to 2/7, or 9_-2_^+3^% to 29_-19_^+26^%). Follow-up observations of the seven offset and dual AGN candidates in AGES will definitively distinguish velocity offsets produced by dual SMBHs from those produced by narrow-line region kinematics, and will help sharpen our observational approach to detecting dual SMBHs.
