The 1.8 Msec Chandra COSMOS Survey is the largest Chandra GO program awarded to date. COSMOS is a pan-chromatic survey of the extragalactic sky designed to be both large and deep enough to study galaxy and quasar evolution in typical environments with minimal 'cosmic bias'. The location of COSMOS near the equator (10h +02deg) allows all major and future facilities (esp. EVLA, ALMA) to target this 2 sq. deg.region. Both space - HST, Spitzer, GALEX, XMM - and ground-based - VLA, Subaru, CTIO, KPNO, CFHT, Magellan, VLT - have already surveyed the area to faint limits. The central region of the COSMOS field is now the target of deeper surveys by the VLA and VLT, and proposed for GALEX and VISTA.

The Chandra COSMOS Survey (C-COSMOS) - to be carried out 2006/2007 - will cover the central area of the COSMOS field to ~2e-16 cgs (0.5-2keV) with a series of 36 heavily overlapped ACIS-I 50 ksec pointings, giving a total exposure of 200 ksec over ~0.8 sq. deg. This overlap gives uniform exposure over the whole area.

By going for area over extreme depth, C-COSMOS sources will typically be bright enough to be also detected in the rest of the COSMOS data set, allowing ready follow-up of their multi-wavelength their properties. The depth of C-COSMOS was chosen to 'break through' the flux level where the AGN creating the bulk of the X-ray background dominate, and so detect significant numbers of starburst galaxies, up to redshifts ~0.9, comparable with the depth of the COSMOS galaxy surveys.

• COSMOS (Caltech)
• COSMOS IRSA
• Local C-COSMOS Site (Password Access Only)

Martin Elvis, Tom Aldcroft Antonella Fruscione Heng Hao Amy Mossman