One of the primary objectives of the HEASARC is to provide a user-friendly,
multi-mission, multi-wavelength environment in which to access the data that it
archives. An On-line Service has been established to help accomplish that
objective. Users who log in to the Service can access data from orbiting
observatories (the list of which currently includes Cos-B, HEAO-1, Einstein,
EXOSAT, Ginga, IUE, and ROSAT) along with many well-known astronomical
catalogs. The database system and software within the On-line Service allow
users to search and locate data, and then to either analyze it remotely, or to
export it to their home computers for analysis there.
The HEASARC On-line Service resides on the NSSDC Data Archive and Distribution
Service, (NDADS), a VAX cluster at GSFC. A captive account called XRAY has
been set up on the NDADSA VAX to provide secure remote access to the database
system and software. A program called XOBSERVER controls the use of the XRAY
account. XOBSERVER provides:
tasks to transfer files to the user's computer.
A user logs in remotely to XRAY and then runs database and analysis tasks to
search through astronomical catalogs, locate data files, and analyze or
transfer data. The XOBSERVER program originated from the EXOSAT Database
System, which was written by the European Space Agency's (ESA's) Space Science
Department between 1986 and 1990 to provide remote access to archival data
obtained by EXOSAT. Recently the HEASARC, the ESA, and the University of
Leicester, UK, have been jointly developing the system to provide a generic
environment for on-line astrophysics archival access and analysis. The system
was renamed XOBSERVER in recognition of its multi-mission nature and to
distinguish the controlling environment from the analysis and database tasks.
Logging in
The first issue of Legacy and the HEASARC "On-line Users Guide" describe
in detail how to use the captive account. Briefly, users can log in to the
HEASARC On-line Service 24 hours a day by setting host to or telnetting to
NDADSA.
$ set host ndadsa (set host 15761)
or
$ telnet ndadsa.gsfc.nasa.gov
(128.183.36.17)
Once the user has connected, NDADSA will signal its presence and ask for a
username. The user enters XRAY at the USERNAME prompt, and is logged in to the
On-line Service captive account. A new user, or one who is logging in from a
different location than usual, will be asked to type a HEASARC username. This
should be the user's first initial and last name, (e.g., INEWTON).
Once the user has successfully logged in to the captive account, the
HEASARC> prompt appears; this indicates that HEASARC XOBSERVER is
ready to receive input. At this point there are a number of options available
to the user, including accessing the databases or the bulletin board, running
data analysis programs, or transferring files. On-line help can be accessed by
simply typing help at the HEASARC> prompt.
The BROWSE databases
Typically, a user will begin by running the database access program, BROWSE, to
search through and display the available data and catalogs. BROWSE is a
command-driven program that uses a database management system to select data
from tables of information and results, and access any associated data product
files. The analysis tasks available within the XOBSERVER environment can be
executed from within BROWSE, or outside of it, whichever the user prefers.
BROWSE is started by typing
HEASARC> browse [dbname]
The optional parameter dbname specifies the name of the database to be
accessed; if no dbname is given, BROWSE will prompt for one. Typing a
? or carriage return will display a list of all the available HEASARC
databases. Once a user chooses a database to "browse", that database is loaded
as the current database, and the user enters commands to manipulate the
database entries. Users can sort, search, display and plot entries in the
database, and can also cross-correlate the data with entries in other
databases. In addition, the data can be passed to other programs for spectral,
timing, and image analysis, and interactive plotting and fitting.
Note that here the word "database" simply means a collection of information or
results which has been organized into a table. The rows in the table are
called "entries", and the columns are "parameters". HEASARC databases
typically contain observation logs, astronomical catalogs, bibliographies, file
names and locations, and/or data analysis results. In the case of an
observation log, the database may contain one entry for each observation, with
the associated parameters being the observation date, time, and duration,
pointing coordinates, and instrument used. Catalog databases often are
organized with one entry (or row) for each source, and parameters (or columns)
such as source names, coordinates, count rates, magnitudes, and
classifications.
At present, there are more than 80 HEASARC databases on line. A listing of
some of the available databases appears in Table 1. The databases can be
accessed separately, or cross-correlated with one another to find matches in
common parameter fields. For example, celestial coordinates can be used to
find all matching sources in two databases, based on positional coincidences
within a specified radius. Some of the 30 new databases since the last issue
of Legacy are described in the section Recent Additions to the HEASARC
On-line Service.
Table 1: Sample of HEASARC On-line Service Databases
20CMNORTH Catalog: 20cm radio
3ARIEL Catalog: 3A (Ariel-V)
RC3 Catalog: 3rd Ref Cat of Galaxies
4UHURU Catalog: 4th Uhuru X-ray
6CMNORTH Catalog: 6cm radio
ABELL Catalog: Abell Clusters
KUEHR Catalog: Extragal. Radio Sources
CNS3 Catalog: Gliese Nearby Stars 3
SNRGREEN Catalog: Green SNRs
GSC Catalog: HST guide stars
HD Catalog: Henry Draper
QSO Catalog: Hewitt & Burbidge QSO
ZCAT Catalog: Huchra CfA Redshift
IRASID Catalog: IRAS FSC Associations
IRASFSC Catalog: IRAS Faint Sources
IRASPSC Catalog: IRAS Point Sources
KONUS Catalog: Konus 11 & 12
PULSAR Catalog: Lyne Pulsar
MCKSION Catalog: McCook & Sion WD's
MRC Catalog: Molonglo Radio Sources
PVOTRIG Catalog: PVO gamma-ray bursts
RITTER Catalog: Ritter CVs & LMXRBs
SAO Catalog: SAO stars
HXRBS Catalog: SMM HXRBS
WOOLLEY Catalog: Stars <25 pc from Sun
TD1 Catalog: Stellar UV Fluxes
VSTARSUSP Catalog: Suspected Variables
VSTARS Catalog: Variable Stars, 4th ed.
VERON89 Catalog: Veron Quasars & AGN
DOCUMENTS Documents: HEASARC
LE EXOSAT CMA (central 6 arc min)
CMA EXOSAT CMA Database
CMAIMAGE EXOSAT CMA Images
GS EXOSAT GS database
ME EXOSAT ME database
PR EXOSAT PR database
TGS EXOSAT TGS L and R orders
TGS2 EXOSAT Transmission Grating
EXOPUBS EXOSAT bibliography
EXOLOG EXOSAT observation log
EMSS Einstein EMSS catalog
HRICFA Einstein HRI CfA Source List
HRIEXO Einstein HRI EXOSAT source list
HRIIMAGE Einstein HRI Image Database
HRIPHOT Einstein HRI Photon Event Data
IPCIMAGE Einstein IPC Image Database
IPC Einstein IPC Source List
IPCSLEW Einstein IPC slew catalog
SSS Einstein SSS database
SSSHME Einstein SSS dbase-IBM listing
EINLOG Einstein observation log
GROLOG GRO Phase I Viewing Plan
GINGALOG Ginga LAC Log Catalog
GINGAMODE Ginga LAC Mode Catalog
A1 HEAO 1 A1 X-ray Catalog
A2LED HEAO 1 A2 LED Sky Catalog
A2PIC HEAO 1 A2 Piccinotti Catalog
A2POINT HEAO 1 A2 Point Catalog
A3 HEAO 1 MC LASS Catalog
A4 HEAO 1 A4 X-ray catalog
IUE IUE ULDA database
COSB COS-B Photon Catalog
SMMGRS SMM GRS Gamma-Ray Burst D'base
XRAY Master Catalog: X-ray
XCOLL Master Catalog: X-ray Collimators
OPTICAL Master Catalog: optical
RADIO Master Catalog: radio
ROSTL1 ROSAT AO1 long-term timeline
ROSTL2 ROSAT AO2 long-term timeline
ROSTL3 ROSAT AO3 long-term timeline
WFCBSC ROSAT WFC Bright Source Cat.
ROSAO ROSAT accepted AO proposals
ROSATLOG ROSAT log of observations
ROSOBS ROSAT observations status
ROSSTL ROSAT short-term timeline
Recent Additions to the HEASARC On-line Service
Since publication of the first edition of Legacy, there have been many
additions to the list of Browse databases available within the HEASARC On-line
Service. Several new catalogs and datasets have been placed on-line, while
others have been updated to newer and more complete versions. The following
databases have been recently acquired or updated and are now accessible through
Browse:
KUEHR - Catalog of Extragalactic Radio Sources
The catalog is a compilation of 518 extragalactic radio sources with flux
densities greater than 1 Jy at 5 GHz. It contains sources from the NRAO-MPI 5
GHz Strong Source Surveys and from re-observation at 5 GHz of sources found in
the Parkes 2.7 GHz surveys. Included are radio flux densities, radio
positions, object classes, visual magnitudes, redshifts, and spectral
indices.
SNRGREEN - Catalog of Galactic SNRs
This catalog contains information on 174 galactic supernova remnants as
published in Green 1988, Astrophys. Space Sci., 148, 3, and
updated by Green 1990, PASP (in press).
ZCAT - CfA Redshift Catalog
The CfA Redshift Catalog incorporates velocity data from the Whipple
Observatory and other sources, as well as velocities from earlier compilations.
It includes BT magnitudes, some UGC numbers, and increased "accuracy" in the
velocity source information. The data were assembled mainly for the study of
the large scale structure of the universe; thus the catalog is nearly complete
in redshift information, but not necessarily complete in categories such as
diameter, magnitude, and cross-references to other catalogs.
IRASFSC - IRAS Faint Source Catalog
The IRASFSC database contains the IRAS Faint Source Catalog (FSC)
non-associations data. (The associations data for the IRAS FSC is contained in
the IRASID database.) Version 2.0 of the FSC, released in September 1990, is a
highly reliable catalog which is 2.5 to 3 times more sensitive than the IRAS
Point Source Catalog (PSC). The FSC also contains 99,973 infrared sources
which are not in the PSC.
IRASID - IRAS FSC Associations Catalog
The IRASID database contains the associations data for the IRAS Faint Source
Catalog (FSC). The main catalog of non-associations data is contained in the
IRASFSC database.
KONUS - Konus 11 & 12 Gamma-ray Burst Catalog
This catalog contains gamma-ray burst data from the KONUS instruments,
which were flown on pairs of Venera spacecraft. Veneras 11/12 were launched in
September 1978; bursts were recorded through January 1980. Veneras 13/14 were
launched in November 1981 and were operational through March 1983. The Veneras
were interplanetary spacecraft which flew to Venus, and thus each spacecraft
had whole sky coverage for most of its mission.
PVOTRIG - Pioneer Venus Orbiter Triggered Gamma Ray Bursts
This catalog gives information on the triggered events detected by the
PVO instrument from September 14, 1978 to July 21, 1988. The catalog comes
from the Ph.D. thesis of Kuan-Wen Chuang (UC Riverside, 1990).
VERON89 - Catalog of Quasars and AGN
This catalog is the 4th edition of Veron-Cetty and Veron, "A Catalogue of
Quasars and Active Galactic Nuclei". It contains data for quasars, active
galaxies, and BL Lac objects.
GROLOG - Gamma Ray Observatory Viewing Plan
This database contains the Phase 1 viewing plan for the Compton Gamma Ray
Observatory. It gives target names and coordinates, instrument used, and start
and end times for each Phase 1 observation.
COSB - COS-B Photon Catalog
This is a catalog of photon data from the European Space Agency satellite
Cos-B. Cos-B was dedicated to gamma-ray astronomy in the energy range 50 MeV
to 5 GeV, and carried a single experiment, a spark chamber telescope, developed
in a collaboration by six European institutes. The experiment became
operational on August 17, 1975, and was switched off on April 25, 1982, when
on-board resources were exhausted. During this period, 65 observations,
typically of a month's duration, were performed. Circular sky regions of about
40 degrees in diameter were covered in each observation. The majority of the
pointings were distributed along the galactic equator, but 15 observations were
devoted to regions at high (>20 degree) galactic latitudes. Several regions
of specific interest were repeatedly observed.
RC3 - Third Reference Catalogue of Bright Galaxies
The RC3 database contains the machine-readable version of the Third
Reference Catalogue of Bright Galaxies (RC3.9) by G. de Vaucouleurs, A. de
Vaucouleurs, H.G. Corwin, R.J. Buta, P. Fouque, and G. Paturel, 1991.
CNS3 - Catalog of Gliese Nearby Stars
This catalog is a preliminary version of the Third Catalogue of Nearby Stars
(CNS3) compiled by Wilhelm Gliese and Hartmut Jahreiss (Astronomisches
Rechen-Institut, Heidelberg, Germany). It contains information about every
known star within 25 parsecs of the Sun.
HRIPHOT - Einstein HRI Images in Event List Format
The HRIPHOT database contains information in Event List format from the High
Resolution Imager (HRI) aboard the Einstein Observatory. The Einstein HRI
detector provided an arrival time and position for each X-ray event occurring
within its 24-arcmin field-of-view and within the energy range 0.15 keV to 3.5
keV. The HRIPHOT database points to 870 HRI photon events files, stored in
FITS format.
IPCSLEW - The Einstein IPC Slew Survey source list
The IPCSLEW database contains the most recent version of the list of
sources detected by the IPC Slew Survey. It was created in March 1992 and
contains 819 entries. The original IPC Slew Survey source list was released on
CD-ROM and contained 1067 sources. The list was updated in 1991 to remedy a
software bug which omitted a thin slice of RA near 24h; the bug fix yielded 8
additional sources, to bring the total to 1075. The list, however, was found
to contain a large fraction (10 to 15 percent) of unreliable sources,
especially those sources with o(<,~) 5 photons. The unreliable sources were
rejected in producing the latest version of the source list, so that it now has
an estimated false source rate of only 2 percent, and contains 256 fewer
sources than the previous version.
OPTICAL - Master Optical Catalog
The OPTICAL database is a newly-revised master catalog containing selected
parameters from several optical source catalogs. OPTICAL was created by
copying all of the entries and common parameters from the HEASARC databases
which contain the following catalogs:
Abell Catalog of Galaxy Clusters (1989)
Ritter Catalog of CV's, X-Ray Binaries & Related Objects (1990)
General Catalog of Variable Stars, 4th ed. (Kholopov 1985-88)
Smithsonian Astrophysical Observatory Star Catalog (1989)
McCook & Sion White Dwarf Catalog (1987)
Hewitt & Burbidge Catalog of Quasi-Stellar Objects (1987)
Woolley Catalog of Stars within 25 Parsecs of the Sun (1970)
Veron-Cetty & Veron Catalog of Quasars and AGN (1989)
Green Catalog of Supernova Remnants (1988, updated 1990)
CfA Redshift Catalog (Huchra 1989)
ROSTL3 - The ROSAT AO3 Long-term Timeline
The ROSTL3 database is based on the ROSAT AO-3 (part 1) long-term timeline (MPE
number 1000). The first half of the AO-3 timeline was made in June 1992, and
covers the interval June 15 to December 7, 1992. The ROSTL3 database, provided
by the ROSAT U.K. Data Center, contains details of all scheduled pointed
observations on a one entry per slot basis, where a "slot" is an interval of
constant celestial pointing with detectors on.
WFCBSC - ROSAT Bright Source Catalog
The WFCBSC database contains the ROSAT Wide Field Camera Bright Source
Catalogue. It contains 384 bright EUV sources found during the ROSAT all-sky
survey of July 1990 to January 1991. The information in this pre-publication
database is based on what will be published by Pounds et al. in
MNRAS.
The HEASARC continues to collect catalogs and data from various sources and
ingest them into the database system in the HEASARC On-line Service. The
current listing of available SYSTEM databases may be obtained on-line by typing
Browse at the HEASARC> prompt and then entering either a
? or just a carriage return at the Database: prompt.
File transfer options
Files that are created during an XOBSERVER session are stored in the user's
directory, including any extracted data products, and log and history files
created by the XOBSERVER programs. (A complete record of all output from a
user's BROWSE session and XOBSERVER session is written to log files called
BROWSE.LOG and XOBSERVER.LOG.) These files can be transferred from the user's
directory to his or her home computer. The transfer can be made either from
the XRAY account using the mail or send commands, or from the
user's computer using the VMS copy command. The file transfer method
used depends on whether the file is ASCII or binary, and whether it is a
VMS-to-VMS or VMS-to-UNIX transfer.
Help documentation, which describes what each file transfer command is suitable
for, is contained in the XOBSERVER User's Guide. Type help at
the HEASARC> prompt to access the guide.
Spectral, timing and image analysis
Users can access various analysis programs from within the XOBSERVER
environment. The spectral, timing and image analysis packages are all part of
the XANADU analysis package and are called XSPEC, XRONOS and XIMAGE,
respectively.
All three of these analysis programs can be run within BROWSE or as a
stand-alone procedure. More details about how to run these programs are
available in the first issue of Legacy. Full documentation is available
upon request from heasarc@heasrc.gsfc.nasa.gov.
XSPEC
On-line help documentation on XSPEC can be accessed from a number of places.
Users can type help when inside XSPEC for descriptions of commands.
Also, both the BROWSE and the XOBSERVER on-line documentation contain
information about XSPEC and examples of how to use it; the former can be
accessed by typing help within BROWSE, and the latter by typing
help at the HEASARC> prompt.
For users who wish to copy spectral files back to their home computers to
analyze them, XSPEC and its associated programs are available for local
installation. Both the VAX/VMS and Sun-UNIX versions can be obtained by
sending e-mail to ndadsa@request.gsfc.nasa.gov), or Karen Smale at ksmale@heasrc.gsfc.nasa.gov).
XRONOS
Each of the XRONOS tasks is explained in the on-line help documentation within
the program itself; the documentation is accessed by typing help at
the XRONOS> prompt, or replying help to any question asked
by a XRONOS application. Information about XRONOS can be found in the on-line
help for BROWSE and XOBSERVER as well.
At present, XRONOS is available for remote installation on VAX/VMS machines,
and will soon be available in Sun-UNIX and HP-UX versions as well. Information
can be obtained from Lorella Angelini at angelini@heasrc.gsfc.nasa.gov.
XIMAGE
Detailed help documentation for XIMAGE can be accessed from within the program
by typing help. Information on XIMAGE and associated image analysis
routines is also contained in the XOBSERVER help and in the BROWSE help.
XIMAGE can be installed locally on the user's computer. Currently, only a
VAX-VMS version is available; Sun-UNIX and HP-UX versions are under
development. Contact Lorella Angelini at angelini@heasrc.gsfc.nasa.gov for
more information.
QDP/PLT
The plotting and function-fitting package that is used within the XOBSERVER
environment is called QDP. The QDP package is used by the BROWSE, XSPEC and
XRONOS programs to plot light curves and spectra. From each of these programs,
a QDP file can be generated, and later input to QDP for plotting and fitting.
Users can also generate QDP files in the XRAY account, and then transfer them
to their home computer, where they can replot and manipulate them locally.
Users who wish to install a copy of QDP on their home computers can contact the
HEASARC (write to heasarc@heasarc.gsfc.nasa.gov). QDP is available in VMS, UNIX and MS-DOS
versions. A full help facility is available within QDP. There is also
information about QDP in the on-line documentation for XOBSERVER and BROWSE.
Obtaining user's guides and information
In addition to the extensive on-line help in the XRAY account, a variety of
documentation is available from the HEASARC. Table 2 contains a list of the
currently available documents. Please see the BROWSE database called DOCUMENTS
for a more up-to-date list. Requests for documentation should be sent to
NDADSA::REQUEST, or request@ndadsa.gsfc.nasa.gov.
In addition to the above documents, the CD-ROM "The Einstein Observatory SSS,
MPC, and FPCS Data Products" is available from the HEASARC by contacting
ndadsa@request.gsfc.nasa.gov.
User questions or problems with any of the XOBSERVER software or the database
system should also be reported to ndadsa@request.gsfc.nasa.gov. Comments are welcome, and
user suggestions will be implemented when possible.
Table 2
NAME VERSION TYPE DATE
Available HEASARC Databases CAT 91 Jun
BROWSE User's Guide UG 91 Feb
Definition Panel Report RPT 89 Jul
File Struct & Format of Processed Einstein UG 88 Dec
Guidelines for PDMP's RPT 91 Feb
HEAO 1 A-2 Analysis UG 87 Jul
HEAO A-2 Catalog of Pre-HEAO X-ray sources CAT
HEASARC Implementation Plan RPT 90 Jan
HEASARC Online Service/XOBSERVER Ref Guide BRO 91 Dec
HUG Recommendations RPT 91 Jun
Interoperability Gateway Guide UG 90 Mar
Legacy - The HEASARC Journal (Number 1) JOU 92 May
Legacy - The HEASARC Journal (Number 2) JOU 92 Nov
List of Approved ROSAT Observations (AO-1) CAT 90 Jan
List of ROSAT Observations (thru April 92) CAT 91 Nov
MIPS Flyer BRO 91 Jan
MIPS User's Guide UG 90 Dec
PGPLOT Graphics Subroutine Library UG 86 Jan
PROS Description (NRA 91-OSSA-3 Append. H) RPT 90 Dec
PROS: Data Analysis for ROSAT PPR 91 May
QDP/PLT User's Guide UG 91 Jun
ROSAT Data Products Guide 2.0 UG 91 Jul
ROSAT Mission Description (91-OSSA-3App.F) RPT 91 Jan
ROSAT Mission Description Addendum RPT 91 Nov
ROSAT Newsletter (Number 1) NL 89 Feb
ROSAT Newsletter (Number 2) NL 89 Sep
ROSAT Newsletter (Special Edition) NL 90 Jan
ROSAT Newsletter (Number 4) NL 90 Jul
ROSAT Newsletter (Number 5) NL 91 Jun
ROSAT Newsletter (Number 6) NL 91 Nov
ROSAT Newsletter (Number 7) NL 92 Sep
ROSAT brochure BRO 90 Oct
ROSAT-PROS User's Guide UG 91 Aug
User Manual for SAOimage UG 91 Jan
User's Guide to HEAO A-2 Data Analysis Sys UG 88 Jun
XIMAGE - X-ray Astron Image Analysis Facil UG
XOBSERVER Available Databases UG 91 Dec
XOBSERVER Online User's Guide UG 91 Dec
XRONOS - Timing Analysis Software Package 2.0 UG 91 Oct
XSPEC - X-ray Spectral Fitting Package 7.0 UG 90 Nov
XSPEC User's Guide UG 91 Feb
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