-- Erase the words written in the white window and replace them with the following
query; set the output format to HTML.
SELECT
p.ra, p.dec, s.z, p.petroMag_r,
p.petroR90_r, p.lnLExp_r, p.lnLDeV_r, p.expAB_r, p.isoPhi_r
FROM PhotoObj p, SpecObj s, SpecLine l
WHERE
p.SpecObjID = s.SpecObjID AND
p.SpecObjID = l.specobjID AND
l.lineID = dbo.fSpecLineNames('CIV_1549') AND
p.ra >= 120 AND p.ra <= 180 AND
p.dec >= 0 AND p.dec <=10 AND
s.z >= 5.0
order by p.ra
This will run for a short time. It will return you a very few (exactly 4) objects.
Use the query itself and what it returns to answer a few questions:
3.3 Explain the criteria that are being used by this query to identify objects
in the database. (This will require you to explore the syntax of the
query --- but it should be pretty obvious!)
3.4 Make a table containing the returned properties, and refer to this table
as you answer the next three questions.
Use the
DR4 Navigator and Explore Tools (http://cas.sdss.org/dr4/en/tools/chart/navi.asp)
to investigate the image and spectrum of each object. As before, here are handy links for you to use.
3.5 Explain as best you can what quantities are returned by the SQL query for
each object. You do not have to give precise definitions; rather the images to help you figure out
what the parameters measure. (Hint: "Petro" stands for
"Petrosian", "__r" means quantities derived from the r-band filter images, "phi" refers to a "position
angle", "Exp" and "DeV" refer to exponential and deVaucouleurs' fits to the surface brightness profile,
"iso" stands for "isophote", "AB" refers to the ratio a/b of the major to minor axis.)
3.6 Comment on the appearance of each object, and its surroundings, in the SDSS image.
3.7 Note the lines present in each spectrum and
discuss the similarities and differences among the spectra of the four objects.
Last modified: Sun Oct 7 11:30:88 2007
by martha
