Nature of Broad Line Region in AGNs Xinwen Shu Department of Astronomy University of Science and Technology of China Collaborators: Junxian Wang (USTC) Hai Fu (UC, Irvine) Wei Zheng (JHU) 2012, March 17, NAOC

The detection of broad optical lines in the polarized spectrum of the archetypical Seyfert 2, NGC 1068 supports UM: any observational difference of AGNs are due to obscuration along the line-of-sight to the source However, about half of the brightest Seyfert 2 galaxies appear not to have hidden broad-line regions (HBLR) in their optical spectra, even when high-quality spectro-polarimetric data are analysed (e.g. Tran 2001, 2003)

The existence of a critical threshold in luminosity and/or Eddington rate has been confirmed on observational grounds (e.g. Nicastro 2003, Shu et al. 2007, Elitzur & Ho 2009, Wu et al. 2011, Marinucci et al. 2012) However, the physical mechanism that regulates the formation of BLR is still unclear (e.g. Nicastro et al. 2000, Laor 2003, Elitzur et al. 2009, Cao 2010) Seyfert 2 galaxy without BLR? Nicastro et al Q2131−427 log(L bol /L Edd )~-2.6

Deep search for hidden broad emission lines: optical spectropolarimetry and near- infrared spectroscopy, Tran 2011

Motivation Bian et al. (2007) Low-z (<0.25) SDSS sample — High S/N (>20σ) — Narrow Hα and Hβ in the optical spectrum — High luminosity and BH mass — low accretion rate — Host galaxy morphology (environment studies) — Unique look at a rare population A sample of Seyfert 2s with high luminosity and low accretion rates is useful to distinguish the physical driver on the formation of BLR Q2131−427 log(L bol /L Edd )~-2.6 Log(L[OIII])~42.15 ， Panessa et al. 2009

SDSS Spectroscopy and imaging —Well optically-defined Seyfert 2 — A remarkable feature in the spectrum is very broad [O III] emission line, indicating a relatively massive black hole in galaxy nucleus. —Unique stage of Seyfert evolution

Sample Selection 7/12 local targets selected for Hale/Triplespec follow-up, to search any IR broad lines such as Paβ and Br ϒ if exist, which are less affected by extinction than optical. Orbits Z~7 Candidates CLASH 50 ~10 HIPPIES U Name (SDSS) r (mag) zMBH (10 8 ) L/Ledd (10 -3 ) RASS (cts) J <0.05 J <0.05 J <0.05 J J <0.05 J <0.05 J <0.05

Other TAP-related observational projects in future

1<z<3 star-forming galaxies in cluster fields Abell 383, Newman et al Motivation: —they are at redshifts corresponding to the peak epoch of SFR, e.g., Ly et al —they are likely lower redshift analogs of the high-z LBGs —magnifications by cluster help to probe intrinsically faint and less massive systems —will help gain insights into the physical and morphological nature of high-z LBGs, and cosmic reionization —some of bright sources will allow the spectroscopic follow-up observations

Z~2 highly magnified lensed galaxies, Wuyts et al. 2012

A highly magnified (~3mag) z~1.1 low-luminosity star-forming galaxy in Abell 383, Smith et al Near-Infrared spectroscopy reveals strong [O II] emission line

Search for UV bright objects in cluster fields Multi-band SED (unpublished) confirms the low-luminosity young star-forming galaxy from near-infra spectroscopy, where strong [O II] emission line suggests high ongoing star-formation. New CLASH (Cluster Lensing And Supernova survey with Hubble) imaging of Abell 383 in 16 bands from 225nm to 1.6 um

CLASH now observed 10 clusters with FOV of ~50 arcmin2, using UV color-color diagram and photometric redshift, we selected ~200 UV detected sources at z~1-3 ~30 z~1-3 galaxies have intrinsical r-band magnitudes <21 mag We would like to use MMT/redchannel (370nm-1.1um) to observe [O II] for z~1-2 UV bright candidates, and MMT/bluechannel to detect Lya for those at z~2-3. Combining SED fitting with follow-up spectroscopy observations, we shall gain new insights on the physical conditions (redshift, extinction, metallicity, dynamic, etc) of UV bright z~1-3 sources in CLASH cluster fields

Thank you and TAP, Palomar Hale/TripSpec very much