Top Banner
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 - debated nature since Einstein Obs. (Elvis et al. 1 ilution of optical AGN signature by galaxy light bsorption adiatively inefficient accretion flow (little optic
14

X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

Dec 20, 2015

Download

Documents

Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox,

Jones, Murray, Vikhlinin, Kenterand the Bootes Team

Bootes Survey9.3 sq. degrees with Chandra

4632 X-ray sources1600 optical spectra

NOAO Deep Wide Field SurveyAGES Optical Spectroscopic Survey

20,000 galaxy spectraKey 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)

Page 2: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

2

The XBootes Survey• 126 ACIS 5 ksec pointings

• Joint GTO (Murray) and GO (Jones) program

• 14h 32m +34 06’

• 4642 sources detected (>=2 cts)– 625 spurious

• 3293 sources detected (>=4 cts)– 22 spurious

• 42 extended sources (>=10 cts)

• fmin= 4(8)x10-15 erg cm-2 s-1 (0.5-7 keV)

• 98% sources 4 cts matched to NDWFS candidates (R26)

Murray et al. ApJ S 163, 2005

Kenter et al. ApJ S 163, 2005

Brand et al. ApJ, 2006

Page 3: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

3

Spectroscopy in Bootes

• MMT/Hectospec fiber spectrograph – 300 fibers– 6 A resolution, 4000-8000A

• 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

Page 4: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

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. 1991)

Page 5: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

5

Redshift Distribution

XBONGS Broad line AGNNarrow line AGN

XBONGS and NL AGN same distribution

Page 6: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

6

XBONG Magnitude Distribution

XBONGBL (z<1) NL

XBONG counterparts similar to NL/BL AGNpossibly somewhat fainter than NL AGN

Argues against significant dilution of lines by underlying host galaxy for all of sample

Page 7: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

7

Luminosity Distributions

XBONGBL (z<1)NL

•200 XBONGs with Lx>1042 erg/s

•50% with Lx>1043 erg/s

•XBONG’s and NL AGN

•Similar Lx

•Similar Fx/FR

•Argues against dilution for all of

sample

Page 8: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

8

Merged X-ray Spectra

Type (90% error) and no absorption

Red Ellipticals 1.12-1.32

Blue Ellipticals 1.55-1.73

“AGN” 1.83-2.25

Interacting 1.28-1.56 (confirmed by hardness ratios)

Red ellipticals - for an assumed =1.9 power law

nH ~ 0.7-1.1 x 10 22 cm-2 (90% confidence)

• Some “types” absorbed, some not absorbed

Page 9: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

9

IRAC Color-Color Diagrams (following Stern et al.)

Z<0.15

0.15<Z<0.30

0.30<Z<0.45

0.45<Z<0.60

0.60<Z<0.75

0.75<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 AGNNL AGN

Red Blue

BL AGN

Page 10: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

10

Radiatively Inefficient Accretion Flows (RIAF)

•At low accretion rates (Yuan & Narayan)- Optically thick disk is truncated at Rtrans

- Interior to Rtrans 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/Ledd < 0.03

•Test RIAF model with spheroidal sample of XBONGS

-Use optical luminosity as proxy for MBH (108-109 Msun)

- MBH yields Ledd

-Derive AGN LBOL from SED (Elvis et al.)

- For 46 XBONGS, LBOL /Ledd < 0.01

VIABLE MODEL - needs detailed SED’s

Page 11: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

11

Conclusions• Large XBONG sample

– 258 with redshifts to 1

– Variety of optical morphologies

• Origin of XBONG signature– Some dilution at low z (small fx/fR)

– Some absorption - esp. red ellipticals with nH~1022 cm-2

– Many sources show little (<1022 cm-2) absorption

– RIAF (radiatively inefficient accretion flow)

• Spheroidal sample has low Eddington ratio (Lbol/Ledd<0.01)

– Probably some BL Lac’s

XBONG’s are a heterogeneous class

Page 12: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

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

Page 13: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

13

Page 14: X-ray Bright, Optically Normal Galaxies - XBONGS Forman, Anderson, Hickox, Jones, Murray, Vikhlinin, Kenter and the Bootes Team Bootes Survey 9.3 sq. degrees.

14

MMT Bootes surveyOptical spectroscopy: AGES survey w/ MMT/Hectospec

The first sample contains ~1000 broad line AGNs, 80 narrow-line AGNs, and 27,000 “normal” galaxies.