X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees with Chandra 4632 X-ray sources 1600 optical spectra NOAO Deep Wide Field Survey AGES Optical Spectroscopic Survey 20,000 galaxy spectra Key to success is contiguous area and efficient spectroscopy with Hectospec XBONGS - debated nature since Einstein Obs. (Elvis et al. 1981) Dilution of optical AGN signature by galaxy light Absorption Radiatively inefficient accretion flow (little optical/UV)

2 The XBootes Survey 126 ACIS 5 ksec pointings Joint GTO (Murray) and GO (Jones) program 14 h 32 m +34  06’ 4642 sources detected (>=2 cts) –625 spurious 3293 sources detected (>=4 cts) –22 spurious 42 extended sources (>=10 cts) f min = 4(8)x erg cm -2 s -1 (0.5-7 keV) 98% sources  4 cts matched to NDWFS candidates (R  26) Murray et al. ApJ S 163, 2005 Kenter et al. ApJ S 163, 2005 Brand et al. ApJ, 2006

3 Spectroscopy in Bootes MMT/Hectospec fiber spectrograph –300 fibers –6 A resolution, A Spectroscopy –Complete X-ray >4 cts and I<21.5 and galaxies I<19.5 – 1,531 X-ray selected and ~19,000 galaxies –1175 Broad Line Galaxies –50 Narrow Line Galaxies – 258 XBONGS Huge sample 17% of total 0 < z < 1

4 Heterogeneous Class of Objects From optical SED’s and morphology Red Ellipticals 60 Blue Ellipticals 84 Interacting 21 Spirals 9 “AGN” 12 ( Fioc &Rocca-Volmerange 1997; Francis et al )

5 Redshift Distribution XBONGS Broad line AGN Narrow line AGN XBONGS and NL AGN same distribution

6 XBONG Magnitude Distribution XBONG BL (z<1) NL XBONG counterparts similar to NL/BL AGN possibly somewhat fainter than NL AGN Argues against significant dilution of lines by underlying host galaxy for all of sample

7 Luminosity Distributions XBONG BL (z<1) NL 200 XBONGs with L x >10 42 erg/s 50% with L x >10 43 erg/s XBONG’s and NL AGN Similar L x Similar F x /F R Argues against dilution for all of sample

8 Merged X-ray Spectra Type  (90% error) and no absorption Red Ellipticals Blue Ellipticals “AGN” Interacting (confirmed by hardness ratios) Red ellipticals - for an assumed  =1.9 power law n H ~ x cm -2 (90% confidence) Some “types” absorbed, some not absorbed

9 IRAC Color-Color Diagrams (following Stern et al.) Z< <Z< <Z< <Z< <Z< <Z<1.00 z<0.3 Dilution - about 30%; consistent with Georgantopoulos et al. dilution criterion z>0.3 XBONGS concentrated under AGN wedge XBONGS BL AGN NL AGN Red Blue BL AGN

10 Radiatively Inefficient Accretion Flows (RIAF) At low accretion rates (Yuan & Narayan) - Optically thick disk is truncated at R trans - Interior to R trans flow is RIAF (radiatively inefficient; optically thin) - Observed in high state galactic black holes -X-rays from inverse Compton in RIAF -Little optical or UV since no disk at small radii - model requires L/L edd < 0.03 Test RIAF model with spheroidal sample of XBONGS -Use optical luminosity as proxy for M BH ( M sun ) - M BH yields L edd -Derive AGN L BOL from SED (Elvis et al.) - For 46 XBONGS, L BOL /L edd < 0.01 VIABLE MODEL - needs detailed SED’s

11 Conclusions Large XBONG sample –258 with redshifts to 1 –Variety of optical morphologies Origin of XBONG signature –Some dilution at low z (small f x /f R ) –Some absorption - esp. red ellipticals with n H ~10 22 cm -2 –Many sources show little (<10 22 cm -2 ) absorption –RIAF (radiatively inefficient accretion flow) Spheroidal sample has low Eddington ratio (L bol /L edd <0.01) –Probably some BL Lac’s XBONG’s are a heterogeneous class

12 Future Work Deeper & Wider –Chandra and XMM-Newton –Larger samples, better S/N X-ray spectra –Better models applied to ensemble of spectra Optical spectra for fainter sources –Probe to higher z Detailed analysis of optical spectra –Derive equivalent widths and line strength limits –Model NL galaxies, compare to XBONGS Derive SED’s for different classes to test e.g., RIAF models Study local environment –20,000 galaxy redshifts –Measure local density, compare to other AGN classes Remarkable class Promises new insights into accretion process

13

14 MMT Bootes survey Optical spectroscopy: AGES survey w/ MMT/Hectospec The first sample contains ~1000 broad line AGNs, 80 narrow-line AGNs, and 27,000 “normal” galaxies.