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THE INFRARED MEDIUM-DEEP SURVEY. V. A NEW SELECTION STRATEGY FOR QUASARS AT z > 5 BASED ON MEDIUM-BAND OBSERVATIONS WITH SQUEAN KCI 등재 SCOPUS
- 언어ENG
- URLhttps://db.koreascholar.com/Article/Detail/383858
pp.25-35
Multiple color selection techniques are successful in identifying quasars from wide-field broad- band imaging survey data. Among the quasars that have been discovered so far, however, there is a redshift gap at 5 . z . 5.7 due to the limitations of filter sets in previous studies. In this work, we present a new selection technique of high redshift quasars using a sequence of medium-band filters: nine filters with central wavelengths from 625 to 1025 nm and bandwidths of 50 nm. Photometry with these medium-bands traces the spectral energy distribution (SED) of a source, similar to spectroscopy with resolution R 15. By conducting medium-band observations of high redshift quasars at 4.7 z 6.0 and brown dwarfs (the main contaminants in high redshift quasar selection) using the SED camera for QUasars in EArly uNiverse (SQUEAN) on the 2.1-m telescope at the McDonald Observatory, we show that these medium-band filters are superior to multi-color broad-band color section in separating high redshift quasars from brown dwarfs. In addition, we show that redshifts of high redshift quasars can be determined to an accuracy of z/(1 + z) = 0.002 – 0.026. The selection technique can be extended to z 7, suggesting that the medium-band observation can be powerful in identifying quasars even at the re-ionization epoch.
1. INTRODUCTION
2. OBSERVATIONS
2.1. SQUEAN Medium-band Filters
2.2. SQUEAN Medium-band Observations
2.3. Photometric Calibration
3. PROPERTIES OF MEDIUM-BAND PHOTOMETRY
3.1. Filter Response Curves with Quasar Spectra
3.2. Medium-band Spectral Energy Distributions
3.3. Color-Color Diagrams
4. SED FITTING FROM MEDIUM-BANDPHOTOMETRY
4.1. Best-fit Xv2 Values of Quasars and Brown Dwarfs
4.2. Photometric Redshifts of Quasars
5. OBSERVATION STRATEGY
6. SUMMARY
REFERENCES
