- ID:
- ivo://CDS.VizieR/J/PASJ/53/445
- Title:
- ASCA Deep survey in Lockman Hole Field
- Short Name:
- J/PASJ/53/445
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of deep observations of the Lockman Hole field with the ASCA SIS, covering 926arcmin^2^ in the 1-7keV energy range, with a sensitivity 3-5 times deeper than the previous ASCA larger area surveys. Utilizing the results of the ROSAT Ultra Deep survey, we have detected 32, 25, and 15 sources in the 1-7, 1-2, and 2-7keV bands, and only 4, 4, and 1 sources remain unidentified, respectively. The average hardness of the sources detected in the 1-7keV band with fluxes of between 10^-14^ and 10^-13^erg/cm^2^/s corresponds to a photon index of 1.65+/-0.10. Type-2 AGNs show significantly harder spectra than type-1s, which can be explained by absorption column densities of N_H_~10^22-23^cm^-2 at the source redshifts. Fifteen sources are detected in the hard-band (2-7keV), consisting of six type-1 AGNs, six type-2 AGNs, one star, one cluster of galaxies, and one unidentified source. Type-2 AGNs make up a major part of hard X-ray populations in the 2-7keV band at a flux level of 3x10^-14^erg/cm^2^/s (2-7 keV). The redshift distributions of type-1 and type-2 AGNs suggest a lack of high luminosity (optically-defined) type-2 AGNs with intrinsic N_H_<10^23^cm^-2, n the redshift range z~1-2 and/or with intrinsic luminosities larger than 3x10^44^erg/s (2-10keV at source frame).
1 - 10 of 10
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/134/77
- Title:
- ASCA Galactic Plane Survey faint X-ray sources
- Short Name:
- J/ApJS/134/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The X-ray emission from the central region of the Galactic plane, |l|<~45{deg} and |b|<~0.4{deg}, was studied in the 0.710keV energy band with a spatial resolution of ~3' with the Advanced Satellite for Cosmology and Astrophysics (ASCA) observatory. We developed a new analysis method for the ASCA data to resolve discrete sources from the extended Galactic ridge X-ray emission (GRXE). We successfully resolved 163 discrete sources with an X-ray flux down to 10^-12.5^ergs/cm^2^/s and determined the intensity variations of the GRXE as a function of the Galactic longitude with a spatial resolution of about 1{deg}.
- ID:
- ivo://CDS.VizieR/J/ApJ/518/656
- Title:
- ASCA Large Sky Survey
- Short Name:
- J/ApJ/518/656
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out the first wide-area unbiased survey with the ASCA satellite in the 0.7-10keV band around a north Galactic-pole region covering a continuous area of 7deg^2^ (Large Sky Survey; LSS). To make the best use of ASCA's capabilities, we developed a new source-detection method in which the complicated detector responses are fully taken into account. Applying this method to the entire LSS data independently in the total (0.7-7keV), hard (2-10keV), and soft (0.7-2keV) bands, we detected 107 sources altogether, with sensitivity limits of 6x10^-14^ (0.7-7keV), 1x10^-13^ (2-10keV), and 2x10^-14^ergs/s/cm^2^ (0.7-2keV), respectively. A complete list of the detected sources is presented.
- ID:
- ivo://nasa.heasarc/ascamaster
- Title:
- ASCA Master Catalog
- Short Name:
- ASCA
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://nasa.heasarc/ascasis
- Title:
- ASCA SIS Source Catalog
- Short Name:
- ASCASIS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://CDS.VizieR/J/PASJ/55/161
- Title:
- ASCA sources in the SMC
- Short Name:
- J/PASJ/55/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJS/133/1
- Title:
- GIS catalog project : source catalog
- Short Name:
- J/ApJS/133/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first X-ray source catalog of the ASCA Medium Sensitivity Survey (AMSS, or the GIS catalog project), constructed from data at Galactic latitudes |b|>10{deg} observed between 1993 May and 1996 December. The catalog utilizes 368 combined fields and contains 1343 sources with the detection significance above 5{sigma} either in the survey bands of 0.7-7keV, 2-10keV, or 0.7-2keV, including target sources. For each source, the ASCA source name, position, a 90% error radius, count rates in the three bands, detection significances, fluxes, and a hardness ratio are provided. With extensive simulations, we carefully evaluate the data quality of the catalog. Results from cross-correlation with other existing catalogs are briefly summarized.
- ID:
- ivo://CDS.VizieR/J/ApJS/161/185
- Title:
- GIS catalog project : source catalog II
- Short Name:
- J/ApJS/161/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In succession to the first ASCA Medium Sensitivity Survey catalog (AMSS-I), we present the second X-ray source catalog (AMSS-II), constructed from the Gas Imaging Spectrometer (GIS) data covering Galactic latitudes |b|>10{deg} observed between 1997 January and 2000 May. The AMSS-II catalog uses 306 fields and contains a total of 1190 sources detected with significance of >5{sigma} in either the 0.7-7, 2-10, or 0.7-2keV band. The AMSS-I and AMSS-II catalogs list a total of 2533 sources from an area of 278{deg}^2^ and provides a unique database of X-ray sources in the flux range of 10^-13^-10^-11^ergs/cm^2^/s (0.7-10keV). We summarize statistical properties of a complete X-ray sample consisting of 1969 serendipitous selected from AMSS-I and AMSS-II.
- ID:
- ivo://CDS.VizieR/VI/117
- Title:
- Observation Log from ASCA
- Short Name:
- VI/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- ASCA (Advanced Satellite for Cosmology and Astrophysics) is the fourth Japanese X-ray astronomy satellite launched on February 20, 1993 (see Tanaka et al., 1994PASJ...46L..37T) The collaboration between Japanese and US scientists has been carried out in the developments of the X-ray telescopes, the X-ray CCD cameras, and software. ASCA observed more than 3000 targets before stopping scientific observations as a consequence of a huge solar flare occured in mid July, 2000. ISAS continued monitoring operation until the ASCA reentered the atmosphere on March 2, 2001. Scientific instrumentation of ASCA consists of four X-ray telescopes and corresponding focal plane detectors. Focal plane detectors are two X-ray CCD cameras (SIS: Solid-state Imaging Spectrometers) and two Gas Imaging Spectrometers (GIS). With these detectors, ASCA covers the energy range of 0.5-10 keV. This catalogue is a copy of the ASCA Observation log from the Data ARchive and Transmission System (DARTS), provided by the PLAIN center at ISAS/JAXA, Japan. All the ASCA data have been public. The data is archived in a target-oriented (strictly speaking, observation-oriented) structure, i.e., all the data produced from an observation is put into a directory --- although some exceptions exist for observations in very early epoch. Each dataset includes telemetry data, data products (event files, images, energy spectra, light curves, etc.), and calibration data. ISAS provides the telemetry and calibration data, and ASCA data processing center in ADF (Astrophysics Data Facility) at NASA/GSFC reproduces the data products.
- ID:
- ivo://nasa.heasarc/tartarus
- Title:
- Tartarus: Reduced ASCA AGN Data (Version 3.1)
- Short Name:
- ASCA/AGN
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Tartarus database contains the results of a detailed but systematic analysis of ASCA observations of active galactic nuclei (AGN). It contains source and background events files, spectra, ancillary response files and response matrices, images, and assorted light curves for a large number of ASCA AGN observations. Spectral fit results are done by automatic XSPEC fitting. This database table allows easy access to reduced AGN data for the whole community, allowing the maximum scientific return from the data. Availability of publishable light curves, images, and spectra (which can also be readily re-fitted) should be particularly valuable to astronomers with little direct experience in the reduction of X-ray data. Version 3.1 has been created by analyzing all ASCA observing sequences with targets designated as AGN, as indicated by a leading "7" in the ASCA observing sequence number. Version 3.1 contains products for all 611 observing sequences designated as AGN observations. This is a significant improvement over Versions 1 and 2. Moreover, the 611 sequences for which products are available are complete in the sense that either the target object was not detected (in which case an upper limit on GIS2 source counts is given) or the intended AGN target was detected and the data were fully analyzed. In order to obtain the most accurate background subtraction and minimize contamination from any nearby sources, version 3.1 makes more use of custom extraction regions than previous versions. It is expected that version 3.1 will be replaced when the final ASCA calibration is completed. This database table has been created by the Tartarus Team, and they, rather than Imperial College London or the HEASARC, are responsible for the contents. It was ingested by the HEASARC in August, 2005. This is a service provided by NASA HEASARC .
