Some useful astronomical links
NASA Extragalactic Database (NED)
(http://nedwww.ipac.caltech.edu/; telnet ned.ipac.caltech.edu
username: ned) contains information about 800,000 extragalactic objects
which includes 1.3M names and almost a million bibliographic references (since
1983), abstracts (since 1988) and notes on the sources. NED is
the place to start on a project that includes extragalactic
sources and is freely available to any person with an Internet account.
includes an object-based database, it organizes all information around
individual extragalactic objects not by catalogs (Helou et al 1995).
The master list was culled from around 40 major astronomical catalogs plus several
lists from the literature (PG quasars or compact groups of galaxies, for
example). NED team members continuously produce the cross identification of
each source in the list.
The information for each of the sources (if
including information to asses its pedigree
- object type (from the discovery method or original catalog)
- photometric measurements in as many bands as available and
Each entry includes the reference where the information was published.
- radial velocity or redshift
- cross identification
- catalog notes
NED also includes abstracts of dissertations devoted to extragalactic studies defended
since 1980. Dissertation titles and authors only are available for theses since
It is very easy to search for information in NED. Little information is
needed about the object as the query can be started by name, near a position
(in equatorial, ecliptic, galactic or super-galactic) IAU formatted name, near
the position or by object type. The list can be created also in such a way that
object types are excluded from those retrieved inside a searching radius.
If the list is long, a batch job request can be submitted. The user will send
an e-mail message to firstname.lastname@example.org and NED will reply with the
desired information in one or more messages. NED can also be run in a client
mode, making it possible to access the database from within user programs.
To complete the search an image of the object (or the region) can be obtained.
NED can produce images from the Digitized Sky Survey, infrared images from the
IRAS survey and radio maps.