THROUGH THE LOOKING GLASS: HST SPECTROSCOPY OF FAINT GALAXIES LENSED BY THE FRONTIER FIELDS CLUSTER MACSJ0717.5+3745
- Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Department of Physics, University of California, Davis, CA 95616 (United States)
- Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo (Norway)
- The Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (United States)
- INAF—Osservatorio Astronomico di Roma Via Frascati 33, I-00040 Monte Porzio Catone (Italy)
- Institute d'Astrophysique de Paris, CNRS, 98bis Boulevard Arago, F-75014 Paris (France)
- Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)
- Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)
- Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States)
- INAF-Astronomical Observatory of Padova (Italy)
- Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)
The Grism Lens-Amplified Survey from Space (GLASS) is a Hubble Space Telescope (HST) Large Program, which will obtain 140 orbits of grism spectroscopy of the core and infall regions of 10 galaxy clusters, selected to be among the very best cosmic telescopes. Extensive HST imaging is available from many sources including the CLASH and Frontier Fields programs. We introduce the survey by analyzing spectra of faint multiply-imaged galaxies and z ≳ 6 galaxy candidates obtained from the first 7 orbits out of 14 targeting the core of the Frontier Fields cluster MACSJ0717.5+3745. Using the G102 and G141 grisms to cover the wavelength range 0.8-1.7 μm, we confirm four strongly lensed systems by detecting emission lines in each of the images. For the 9 z ≳ 6 galaxy candidates clear from contamination, we do not detect any emission lines down to a 7 orbit 1σ noise level of ∼5 × 10{sup –18} erg s{sup –1} cm{sup –2}. Taking lensing magnification into account, our flux sensitivity reaches ∼0.2-5 × 10{sup –18} erg s{sup –1}cm{sup –2}. These limits over an uninterrupted wavelength range rule out the possibility that the high-z galaxy candidates are instead strong line emitters at lower redshift. These results show that by means of careful modeling of the background—and with the assistance of lensing magnification—interesting flux limits can be reached for large numbers of objects, avoiding pre-selection and the wavelength restrictions inherent to ground-based multi-slit spectroscopy. These observations confirm the power of slitless HST spectroscopy even in fields as crowded as a cluster core.
- OSTI ID:
- 22363967
- Journal Information:
- Astrophysical Journal Letters, Vol. 782, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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