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Proposal Number: 09900045

Title: Chandra Observations of the DEEP2 Fields

PI Name: Stephen Murray

We plan ACIS-I observations of the DEEP2 fields where DEIMOS spectroscopy has measured the galaxy redshifts in the interval 0.7 < z < 1.4 with the primary goal of measuring the environments of different classes of AGN in this redshift interval. We also will study the evolution of AGN in this redshift range, and compare with previous studies at lower redshift.

Proposal Number: 09900059

Title: Intermediate Redshift Groups in the XBootes Survey

PI Name: Gordon Garmire

We propose to observe two intermediate-redshift galaxy groups with Chandra to determine their temperature and X-ray luminosity to r_500. These observations are part of a larger program to observe the 14 brightest groups detected in the XBootes survey. The primary science goals of this project are (1) to exploit the unique multi-wavelength coverage of the XBootes field to investigate the X-ray properties of optically-selected galaxy groups in the 0.15 < z < 0.35 range, and (2) to probe the evolution of group X-ray emission, specifically the Lx/T relation, which is sensitive to non-gravitational effect at these low mass scales. We include a third group which is projected behind a nearby LINER galaxy as an alternate GTO target.

Proposal Number: 09900262

Title: Comparing the emission from an unbiased AGN sample with the X-ray background

PI Name: Roland Walter

Although the populations which make up the medium X-ray background are now well understood, little is known at higher energies. The XRB peaks in the middle of the imaging band of INTEGRAL/IBIS, with which we have made the deepest extragalactic hard X-ray survey, reaching 0.5 mCrab. We detect 42 sources, including 24 well known AGN, 7 unidentified sources and 9 with counterparts of unknown X-ray character. Here we request observations to obtain arcsec positions and measure the medium X-ray spectra of the latter 16 sources. The resulting complete sample will allow to study how the medium and hard XRB differ, test population synthesis models for the XRB, including the prevalence of highly absorbed and Compton-thick sources, and begin a study of the evolution of these populations.

Proposal Number: 09900660

Title: The Evolution of Faint AGN at High Redshift

PI Name: Kirpal Nandra

We propose a very deep (total 800ks/field) Chandra survey of 0.25 deg2 covering 3 contiguous fields in the Extended Groth Strip, which have exceptional multiwaveband coverage obtained by the AEGIS project. These data, in combination with the CDF North and South, will provide a definitive measurement of the evolution of faint, X-ray selected AGN from z=3-4, where the optical number counts start to drop dramatically. In combination with ultradeep Spitzer data in the same region, this survey will also provide a crucial step forward towards a more complete census of AGN activity and the importance of Compton thick AGN at high z, with associated implications for the total accretion budget of the universe.

Proposal Number: 09900679

Title: Detecting the Warm-Hot IGM in Large-Scale Structures

PI Name: Luca Zappacosta

Galaxy overdensities are good tracers of the dark matter large-scale structures (LSS) and therefore of the diffuse warm-hot phase (WHIM) that should be associated with them. The WHIM in LSS is expected to be denser and much easier to detect than the low density one targeted so far along random lines of sight through absorption line studies (with controversial results). Moreover, searching for WHIM signatures in known LSS is safer and much more robust, since redshift of the absorber is known a priori. This efficient method of investigating WHIM has yet to be fully exploited. We have identified 12 bright blazars in the background of LSS. We propose to probe the WHIM in these structures by identifying the associated absorption lines in the LETG/HRC-S spectrum of these AGNs in outburst phase.

Proposal Number: 09900712

Title: Identifying the host galaxies for optically dark gamma-ray bursts

PI Name: Andrew Levan

We propose to use the high spatial resolution capabilities of Chandra to obtain precise positions for a sample of Gamma-ray bursts (GRBs) with no optical afterglows, where the optical light is supresssed relative to the X-ray flux. These bursts are likely to be highly obscured and may have different environments from the optically bright GRBs. Our Chandra observations will (unlike Swift-XRT positions) allow for the unique identification of a host galaxy. To locate these host galaxies we will follow up our Chandra positions with deep optical and IR observations with HST. The ultimate aim is to understand any differences between the host galaxies of optically dark and bright GRBs, and how these affect the use of GRBs as tracers of starformation and galaxy evolution at high redshift.

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The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA.   Email:   cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2025. All rights reserved.