Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 10, 1995 | Published + Submitted
Journal Article Open

A Near-Infrared Search for Line Emission from Protogalaxies Using the W. M. Keck Telescope

Abstract

We present the first results from a near-infrared narrowband search for primeval galaxies (PGs) using the Keck 10 m telescope. We have targeted our fields for three QSOs and one radio galaxy at redshifts z = 2.28 to z = 4.70. We selected narrowband filters in the K band centered on strong emission lines at the redshift of the targets. We reach limiting fluxes between 1.6 × 10^(-17) and 1.0 × 10^(-16) ergs s^(-1) cm^(-2), and cover a total area of ~4 arcmin2. At the redshifts of interest, these flux limits correspond to typical rest-frame line luminosities of ~10^(42)-10^(43) ergs s^(-1), unobscured star formation rates of ~1-100 M☉ yr^(-1), and a sampled comoving volume of several tens of Mpc^3. We have found no candidate PGs at a 2 σ confidence level. We demonstrate that for moderate dust absorption (A_V 2 mag) in a simple dust-screen model, our preliminary survey puts a strong constraint on intrinsic PG luminosities during an initial burst of star formation. In the case of the QSOs, we have used point-spread function subtraction to search for the presence of faint, extended line emission surrounding these radio-quiet active galactic nuclei. We find no evidence for extended emission down to 3.7 × 10^(-17) ergs s^(-1) cm^(-2). This imposes limits on the reprocessed fraction of the QSO continuum emission ranging between 0.02% and 0.29%; if beaming effects are not important, then this implies similarly small covering factors for clouds optically thick to the QSO continuum emission.

Additional Information

© 1995 The American Astronomical Society. Received 1994 November 7; accepted 1995 June 1. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the California Institute of Technology and the University of California. The W. M. Keck Observatory is a scientific partnership between the California Institute of Technology and the University of California. It was made possible by the generous and visionary gift of the W. M. Keck Foundation, and the support of its president, Howard Keck. It is a pleasure to thank W. Harrison, T. Chleminiak, B. Schaefer, and W. Wack for the expert work during our observing run. We would also like to thank David Thompson for many helpful discussions. This work was supported in part by the NSF PYI award AST-9157412 to S. G. D., and the Greenstein and Kingsley Fellowships to M. A. P.

Attached Files

Published - Pahre_1995_ApJ_449_L1.pdf

Submitted - 9506043.pdf

Files

9506043.pdf
Files (453.9 kB)
Name Size Download all
md5:d014417b60e4cb382e664bbfe5df5cdf
201.4 kB Preview Download
md5:c9e2f0710dc1cd8162d8682cc372c9f6
252.5 kB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 18, 2023