Subject: A z=5.28 quasar

From: Wei Zheng

Submitted: Fri, 31 Mar 2000 16:47:54 -0500 (EST)

Message number: 426 (previous: 425, next: 427 up: Index)

Dear APO colleagues:

We are pleased to report the discovery of a quasar at redshift z=5.28. 
The object, SDSS1208+00, has an i'- and z'-band magnitude of 20.7. 

Quasar selections at z>5 suffer increasing contamination from cool stars and
z~1 galaxies. We are carrying out a project to obtain the infrared magnitudes 
for selected SDSS targets. The IR photometry was made at the IRTF in Hawaii,
and the infrared colors enable us to isolate a handful of highly potential 
targets out of a list of several hundreds. Among the four objects for which we 
took optical spectra at the APO 3.5m telescope Thursday night, two quasars at 
z=4.7 and 5.28 are found. The new discovery shows the power of SDSS, as well 
as the effectiveness of IR selection.

These faint targets are a real challenge. The telescope operator, Russet 
McMillan, did a superb job, and the telescope performed extremely well. 
The seeing was among the best we have witnessed. 

The exposure started only shortly before the end of our run, as we had 
difficulty finding any reference objects in this deserted field. 
The next observer, Paula Szkody, let us to finish up. Kindness always pays. 

We wish to thank you all for keeping the telescope in great condition.  It will
surely make more exciting discoveries. 


                          Zlatan Tsvetanov and Wei Zheng

------------------------------------------------------------------------
Zlatan Tsvetanov                    | 
Center for Astrophysical Sciences   | e-mail: zlatan@pha.jhu.edu       
Department of Physics and Astronomy |   http://adcam.pha.jhu.edu/~zlatan   
The Johns Hopkins University        |
3701 San Martin Dr.                 |    Tel: 410-516-8585 (office)    
Baltimore, MD 21218                 |    Fax: 410-516-8260             
------------------------------------------------------------------------


***************************************************************
Wei Zheng 
Department of Physics and Astronomy, Johns Hopkins University
3400 N. Charles Street
Baltimore, MD 21218-2686

E_mail: zheng@pha.jhu.edu
TEL. (410)516-5459, FAX (410)516-8260
***************************************************************

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