NOAO >   Observing Info >   Approved Programs >   2018A-0396

Small NOAO Logo

Program Information for 2018A-0396


PI: James Lowenthal, Smith College, jlowenth@smith.edu
Address: Dept. of Astronomy, Clark Science Center, Northampton, MA, 01063 USA

CoI: Min S Yun, U. Mass
CoI: Patrick Kamieneski, U. Mass
CoI: Daniel Wang, U. Mass
CoI: Itziar Aretxaga, INAOE
CoI: David H Hughes, INAOE
CoI: Kevin Harrington, Universitat Bonn
CoI: Derek Berman, U. Mass
CoI: Roberto Terlevich, IoA + INAOE
CoI: Brenda Frye, U. of Arizona

Title: Gravitational Lens Models for the Brightest Planck SMGs at 1<z<4

Abstract: We have new single-band HST images confirming strong gravitational lensing of the brightest sub-millimeter galaxies (SMGs) in the sky, and here we propose for two more bands in 7 fields with Gemini to build robust lens models. About half of all star formation at high redshift apparently takes place in dust-shrouded galaxies invisible to UV/optical surveys. We have identified some of the most FIR-luminous galaxies in the Universe and have imaged them at 1.1 mm and measured their redshifts $2<z<5$ via CO emission lines using the Large Millimeter Telescope (LMT). Our full sample of 31 SMGs in 29 fields, culled from the Planck and Herschel all-sky surveys, includes 14 of the 21 most luminous galaxies known, with L_FIR>10e14 Lsun and SFR>10e4 Msun/yr. We predicted that most or all are strongly gravitationally lensed, with typical magnification ~ 10x. Our ongoing Cycle 24 HST/WFC3 imaging program of 22 targets confirms this: almost every source shows a large (up to 10" diameter) Einstein ring caused by a massive intervening lensing galaxy, with most of the rest showing large gravitational arcs from massive galaxy clusters at z<1. The HST images in F160W provide spectacular spatial detail and confirmation of the lensing hypothesis, but no color information, so we are unable to build robust lensing models, and the field of view is smaller than a typical cluster diameter at z~1. Here we seek deep r' and z' images with GMOS of the 7 sources (z_med = 2.7) available from GEM-S this semester. These images will immediately allow us to discriminate between foreground and background sources, to discriminate between lensing clusters and isolated lensing galaxies, to detect lensed images of the SMGs and other background galaxies, and then to construct robust lensing models. With lensing models in hand, we can reconstruct the source SMGs to derive structural details of gas and star formation down to scales of 10 to 100 pc, a unique opportunity to understand the fueling and triggering mechanisms of these extreme starbursts.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2018A):  GEM-SQ/GMOSS -- 10.5hrs band 2 (GS-2018A-Q-216 )


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2018A-0396

noaoprop-help@noao.edu

Small NOAO Logo