LAMOST DR2 QSO

董晓怡 (PKU)

吴学兵、张彦霞 (NAOC) 、艾艳丽（中山大学）、杨锦怡、王飞格、杨倩、王澍、

张晨、胥恒、黄文卓、岳明昊、姜沣洋

2015.7.9

Outlines:

QSO and candidate selections DR2 QSO and redshift visual

inspection Emission-line measurements

QSO characteristic:

Credit: C.M. Urry & P. Padovani

QSO properties Rapid-time variability High luminosity Non-thermal radiation Highly compact radiation

region QSO engine – SMBH

accretion gas via accretion disk

The unified model Importance

Mapping BH growth Tracking galaxy evolution Probing intergalactic medium

QSO candidates selection: Point-sources in SDSS DR9 and imag<20 Optical-infrared color-color selections

SDSS/UKIDSS: Y-K>0.46(g-z)+0.82 or J-K>0.45(i-Y-0.366) (Wu& Jia 2010)

SDSS/WISE: w1-w2>0.57 or z-w1>0.66(g-z)+2.01 (Wu et al. 2012)

Data-mining selections Support vector machine (SVM) classifiers (Peng

et al. 2012) Extreme deconvolution method (XDQSO, Bovy

et al .2011) Kernel density estimator (KDE, Richards et al.

2009)

Visual inspection

Visual inspection - ASERA

DR2 QSO - confirmed QSOs Pipeline QSO: ▪ 2852/1241 SDSS DR12 ▪ 29 nqso, 8 BAL, 84 w/o

z Pipeline UNKNOWN: ▪ 5987/1439 DR12(1279

qso). ▪ 1581 qso (27 BAL)/891

DR12▪ 83 Starburst /43 DR12

Pipeline QSO others: ▪ 1005/311 DR12. ▪ 8 nqso, 5 BAL, 18

w/o z

5401 QSOs (695 Huo)

2958 new (504 Huo)

DR2 QSO sky coverage

DR2 QSO: magnitude

Redshift measurements

zvisual/ zpipeline: µ=0.023dex,

σ=0.15, median=0.0

zSDSS/zpipeline: µ=0.016dex,

σ=0.15, median=7.7e-5

Redshift measurements- zdiff vs. zvi and zdiff vs. i mag

Redshift Distribution

Emission line measurements

CIV (1549): z>1.58 MgII (2796/2803): 0.4<z<1.76 Hβ (4861): z<0.75 Hα (6563): z<0.3

Conducting test

Sample: 685 out of 2823 pipeline QSO reported in Shen et al. 2011

Spectral measurements: LA: applying codes to LAMOST spectra SH: Shen et al. results SA: applying codes to SDSS spectra

Emission line measurements - Hα

z<0.3, [6000,6250],[6800,7000]

[NII]6548/6584, [SII]6717/6731, narrow Hα, FWHM < 1200km/sBroad Hα, 1-4 Gaussians, FWHM > 1200 km/s

Example: a Problematic of Hα fit

Z=0.285LA: 967.0 km/s; 1200 km/sSH: 2994.8 km/s; 227.3 km/sSA: 2901.34 km/s; 247.9 km/s

Emission line measurements - Hβ

z<0.75,[4435,4700],[5100,5535]

[OIII]4959/5007: 2 components for eachNarrow Hβ: 1 GaussianBroad Hβ: 4 Gaussian

Comparing FWHM of Hβ

Example: a complicated Hβ fit

LA: 9947.2 km/s; 791.0 km/sSH: 5842.9 km/s; 686.4 km/sSA: 2072.3 km/s; 128.6 km/sDouble peaks? LAMOST z=0.354,SDSS z=0.352

Example: a problematic Hβ fit

z=0.69LA: 9947.2 km/s; 347.1 km/s; SH: 3285.4 km/s; 1200.0 km/s; SA: 1588.8 km/s; 500.0 km/s;

Emission line measurements - MgII

MgII 2796,2803 0.4<z<1.76,

[2000,2700],[2900,3090] Two narrow components

+ two broad components Continuum + FeII

Comparing FWHM of MgII

Comparing FWHM of MgII

Emission line measurements - CIV

z>1.58, [1445,1465],[1700,1705]

One narrow components One broad components Continuum

Comparing FWHM(CIV)

Flux calibration

Virial BH mass

L1350, FWHM CIV L3000, FWHM MgII L5100, FWHM Hβ

Ai et al. 2015

Summary 2454 new QSOs, z<4 0.1-0.2 dex difference between

LAMOST and Shen et al. 2011. 0.1 dex difference comparing with Shen

et al. 2011 (same data set, different methods)

0.1 dex difference because of the low SNR.

Should improve after visual inspection. Calibrate flux with broad-band

photometric data Estimate black hole masses

DR2 QSO catalogue

Redshift FWHM, rest-frame EW for broad Hα,

narrow Hα, [NII]6584, [SII]6717/6731 FWHM, rest-frame EW for broad Hβ,

narrow Hβ, [OIII]4959,5007 FWHM, rest-frame EW for MgII FWHM, rest-frame EW for CIV Continuum luminosity at 5100, 3000,

1350Å Virial BH masses Flag for interesting objects