1. Compiled quasar catalog from LAMOST DR1
艾艳丽
Department of Astronomy, Peking University
Collaborators : Xuebing Wu, Jinyi Yang, Feige Wang, Jianguo Wang, Xiaoyi Dong
and LEGAS team
LAMOST 用户培训会 兴隆

3. From Fan, X. 2014, Xian

4. quasar selection point source contaminations are ≈100, million stars
quasar selection：select candidates then with optical spectra confirmation and redshift measurement
how to select the quasar candidates
based on observed properties

5. unification model and observed spectra
Broad permitted lines: Ha, Hb
Urry & Padovani, 1995
Narrow lines only

6. Similar quasar spectra
Characterize by featureless continuum and series emission lines
Remarkably similar from one quasar to another, compared to galaxy and stars
composite spectra at redshift
Vanden Berk et al

7. SDSS photometric system
Richards et al. 2006

8. Quasar selection I ≈16,000 quasars found by SDSS
based on multi-color optical selection (UV-excess)
Star
quasar
Fan et al. 1999

9. quasar selection -- I
low completeness at redshift 2 –3 as optical colors of quasars similar to those of stars
low completeness
to improve selection completeness
variability selection( Butler 2011)
combined optical—infrared color
----- LAMOST quasar selection
Richards et al. 2006

10. Quasar selection -- II
Optical– infrared color selection ( K-band excess)
Unreddened QSO z=3
Early K star
Reddened QSO z=3
Early M star
Maddox et al. 2008

11. Quasar selection III SDSS_UKIDSS SDSS_WISE QSO z < 2.2
Wu 2010
Wu 2012

12. LAMOST quasar candidates
LEGAS team
Mostly from
SDSS-UKIDSS
SDSS-WISE
Partly from
X-ray, radio, and other selections

13. Observed quasar candidates
≈80,000 observed in pilot survey and first year of regular survey
≈60,000 classified as ‘unknown’ with featureless
Magnitude distribution of ‘unknown’
“unknown”

14. ≈5000 identified QSOs Lines move in cross-over
between blue and red channel

15. ≈ 3000 covered by SDSS DR10 possible emission line variation
continuum variation
but “should be carful”

16. visually checking again
For the ≈2000 newly identified quasars Visually checked again and double checked independently by numbers of our group ≈600 are misclassified as quasar by pipeline visually check redshift and correct some of them for the ≈1400 quasars

17. ≈1400 new quasars identified
Z--Mi distribution

18. Median S/N ratio of emision lines

19. Emission line fitting and measurements
≈1000 with high enough S/N for spectra modelling

20. Continuum flux estimation with SDSS photometry
use SDSS ugriz photometry and quasar continuum and emission line template

21. Black hole mass estimation
Black hole mass distribution

22. Optical –infrared color of the quasar
mostly from SDSS-UKIDSS, SDSS-WISE selection

23. more to do ≈40 X-ray source matched with XMM-Newton
≈100 radio source matched with FIRST
≈20 with repeated LAMOST spectra
special quasar identified, such as, double-peaked quasar, broad-absorption line quasar

24. double-peaked quasar

25. Broad absorption quasar

26. 谢谢