The Palomar Transit Grism Survey

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Session 72 -- High Z Line Measurements; Gravitational Microlensing: Distance Determination
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[72.03] The Palomar Transit Grism Survey

Donald P. Schneider (IAS), Maarten Schmidt (Caltech), James E. Gunn (Princeton)

The Palomar Transit Grism Survey, a program designed to produce a sample of $z$~$>$~2.7 quasars identified by well-defined selection criteria, has recently been completed. The survey consists of six narrow ($\approx$~8.5$'$ wide) strips of sky; the total effective area is 61.47~sq~deg. Low-resolution slitless spectra, covering the wavelength range from 4400~\AA\ to 7500~\AA, were obtained with the 4-Shooter CCD camera for approximately~600,000 objects. The wavelength- and flux-calibrated spectra were searched for emission lines with an automatic software algorithm. A total of 1655 emission features in the grism data satisfied our signal-to-noise ratio and equivalent width selection criteria; subsequent slit spectroscopy of the candidates confirmed the existence of 1052 lines (928 different objects). Six groups of emission lines were detected in the survey: \hbox{Lyman $\alpha$+N V}, C~IV, C~III], Mg~II, \hbox{H$\beta$+[O III]}, \hbox{and H$\alpha$+[S~II]}. More than two-thirds of the candidates are low-redshift ($z$~$<$~0.45) emission-line galaxies; ninety objects are high-redshift quasars ($z$~$>$~2.7) detected via their \hbox{Lyman $\alpha$+N V} emission lines. The survey contains three previously unknown quasars brighter than~17$^{\rm th}$~magnitude; all three have redshifts of~$\approx$~1.3.

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