- Q.: Is there any way to retrieve all of the objects
mentioned in a given paper?
Any of the search options in the "Literature" menu
will return a list of papers.
Click on the reference code for the paper in question. This
will open a new screen with the title and abstract text (if
available), and a link to Retrieve NNN NED Objects
("NNN" is the number of NED objects included in the reference).
This will give you a list of all NED objects mentioned
in the selected paper.
- Q.: How can I find all of the papers written by a
A.: If the author is among the first 20 or so
listed for an extragalactic paper,
select the Author Name
option in the "Literature" menu.
This option will open the
Search for Abstracts by Author Name
screen. Submit the query using the author's last
name as input parameter.
Only the first 160 ASCII characters of the author list and
article title can be searched or displayed on the results
page. Long author lists and long titles are not completely
displayed, and author searches will not return papers when the
name is not included in the first 160 characters of the author
list. Note, however, that NED's abstracts include the full title
and author list, so you may use a Text Search to
find authors in long author lists.
- Q.: How can I find the QSO 2251+113 without doing
a position search?
You may use the IAU Format
option from the "Objects" menu. This option will open the
Search for Object for Given IAU Name
screen. You may then submit the query using an IAU-style name as the
- Q.: In the
Advanced All-Sky Search page,
is it possible to add a filter for the V magnitude of the
A.: Yes. In the "Photometric Constraints"
section of the page, you may choose many different passbands, including
Johnson V. These constraints use NED's "Photometry Data Frames". If an
object does not yet have photometry available through the Photometry
option in the "Data" menu on the home page, it will not be included in a
search depending on photometric constraints.
- Q.: Is there any way to retrieve data concerning
velocity dispersions within galaxies, so I can get, for example, the velocity
distributions of stars as a function of galaxy morphology?
A.: NED does not yet list velocity dispersions
for its galaxies. However, you may use the Text Search
option to scan NED's titles and abstracts, and LEVEL 5, for papers that
contain velocity dispersions.
- Q.: Is there a way that I can get measured fluxes
for my objects using NED?
A.: For single objects, you may search NED's
photometric database using the Photometry option in
the "Data" menu on the home page.
- Q.: Is there a way to perform a NED search for objects
based only on spectroscopic redshifts, and not on redshifts from colors or
A.: We adopt spectroscopic
redshifts whenever they are available. Sometimes, however, only
a photometric redshift is available for an object, or the source of
a redshift is not clearly stated in the published paper. In those
cases, we flag the redshifts if we know that they are not from
spectroscopy. It is still possible, however, for photometric
redshifts to slip in unflagged. In cases of doubt, we urge you to
go back to the published paper to check the source of the redshifts.
- Q.: When I use the search for
References from the "Literature" menu
on NED's home page,
why do I sometimes get results referring to papers that are not related
to my intended object?
A.: The default for this type of search is to
return all "related" objects, that is, all objects with the same root
name. For example, if you search for NGC 1614, you will also get
references for NGC 1614A, NGC 1614:SN 1996D, etc.
If you want just the references for a specific object, set the
Related object name search? option to No.
- Q.: Why does a search for M51 return the wrong
A.: "M51" refers to the pair of galaxies, NGC 5194 and
NGC 5195, not just to the larger spiral NGC 5194. The position that NED
adopts for M51 is therefore the mean position of the two galaxies.
We treat other pairs, triplets, groups, and clusters listed in NED
the same way: we adopt mean positions for all the galaxies rather than
for just the brightest or for the most centrally-located.
Many pairs and triplets in NED have position errors that -- rather than
representing the 95% confidence ellipse -- represent half the separation
of the objects. The "error ellipse" therefore encloses both/all positions
for the member galaxies.