FRI RADIO GALAXIES AT z 1 STUDYING THE

FRI RADIO GALAXIES AT z > 1 STUDYING THE BUILDING BLOCKS OF TODAY'S MOST MASSIVE GALAXIES AND CLUSTERS Marco Chiaberge Space Telescope Science Institute and INAF-IRA Bologna G. Tremblay (STSc. I) A. Capetti (INAF-OATO) D. Macchetto (STSc. I) W. B. Sparks (STSc. I) P. Tozzi (INAF-OATS)

MORPHOLOGICAL CLASSIFICATION OF RADIO GALAXIES FR II LOW POWER HIGH POWER L 178 ~< 2 x 1026 W Hz -1 Fanaroff & Riley 1974 L 178 >~ 2 x 1026 W Hz -1

The radio-loud AGN unification model BL Lac FR I Urry & Padovani 1995

THE HST VIEW of FR I radiogalaxies Complete sample: 33 objects, 32 with HST R-band observations The HST/WFPC 2 snapshot survey of 3 CR radio sources (P. I. Sparks) Chiab, Capetti & Celotti 1999

FRI RADIO GALAXIES AT LOW Z • PROPERTIES OF THE AGN: PROBABLY “RIAF” ACCRETION, RELATIVISTIC JET NO THICK TORI, NO BLR, NO FRI-QSO, NO IR EXCESS (Chiaberge et al 1999) DIFFERENT FROM ALL OTHER AGN MORE SIMILAR TO “INACTIVE” GALAXIES ● ASSOCIATED TO GIANT ELLIPTICAL GALAXIES HOSTING THE MOST MASSIVE BLACK HOLES (e. g. Donzelli et al. 2007, Zirbel & Baum 1997) • ENVIRONMENT: CLUSTERS (e. g Zirbel 1997) MOST FRI ARE HOSTED BY c. D GALAXIES

FR I radio galaxies are known in the nearby universe only In the 3 CR catalog FRIs are present only for z < 0. 2 • A few FR Is (~10) are present in the 6 C and 7 C samples up to z~0. 8 • A few low-power radio galaxies are found in the 2 SLAQ survey (z < 0. 7) (Sadler et al. 2007) • The most distant FR I known is at z ~1 (Snellen & Best 2001)

WHY ARE WE LOOKING FOR FRIs AT 1 < z <2 Cosmological Evolution of FRIs is basically unknown Hints for strong evolution up to z~0. 7 (Sadler et al. 2007) FRI-QSO are absent in the low-z universe: what is the fraction of FRI-QSO at high z? (e. g Blundell et al. 2002, Heywood et al. The role of FRI in the framework of the AGN unification scheme FRIs as probes for studying the formation and co-evolution of the most massive galaxies and most massive BH FRI as tracers of high-z clusters Differently from FRIIs, the AGN does not dominate the emission in crucial bands (IR, X-rays)

FLUX LIMITED SAMPLES CANNOT BE USED The search method must make use of multiwavelength information COSMOS (Scoville et al 2007) is perfectly suitable for this. Basic assumptions: the radio properties of high-z FRIs are similar to those of low z FRIs the optical properties of high-z FRIs are similar to those of high-z FRIIs Radio selection (from FIRST): what is the flux of an FR I radio gal of a certain radio power in the redshift bin 1 < z < 2? (1 m. Jy < F < 13 Morphology: FRIIs are excluded Optical selection: optical counterparts are found using the COSMO catalog (Mobasher et al 2007). Bright sources (detected in SDSS excluded (probably nearby starburst galaxies) U-band dropouts are excluded (z > ~ 2. 5)

RESULTS 182 radio sources in FIRST 133 match the flux requirements 28 FRI candidates 7 FRI-QSO candidates > 4 cluster candidates COSMOS optical data are NOT deep enough to detect a large fraction of cluster galaxies at z > 1

K-z relation for radio galaxies hosts Using photometric redshifts (Mobasher et al 200 and the K-z relation for radio galaxies we can check that our selection criteria work (Chiaberge et al. in prep)

Projected linear size ~100 kpc zphot = 1. 85 1” COSMOS-VLA COSMOS HST/ACS F 814 W 1 orbit

Elliptical hosts (zphot = 1. 31)

VLA ACS WFC F 814 W zphot = 2. 04 10” zphot = 2. 09 z 1. 23 = phot zphot = 0. 72

Using FRIs to find high-z clusters zphot = 1. 3

2' zphot = 2. 09 2' R = 3. m G=V B=B

SUMMARY • We discovered FRI radio galaxies at z >1 • FRIs can be used to study the formation and evolution of the most massive galaxies and their relationship with supermassive black holes • FRIs can be used to find high z clusters Future work: • Spectroscopic redshifts (this week at Galileo, GEMINI? ) • Stacking Xray data to search for cluster/ICM emission • Radio (low and high frequency, higher resolution data) HST DEEP IMAGING TO STUDY HOST GALAXIES AND CLUSTERS – ACS (OPTICAL) – WFC 3 (IR)