A Caltech Library Service

Giga-z: A 100,000 Object Superconducting Spectrophotometer for LSST Follow-up

Marsden, Danica W. and Mazin, Benjamin A. and O'Brien, Kieran and Hirata, Chris (2013) Giga-z: A 100,000 Object Superconducting Spectrophotometer for LSST Follow-up. Astrophysical Journal Supplement Series, 208 (1). Art. No. 8. ISSN 0067-0049. doi:10.1088/0067-0049/208/1/8.

PDF - Published Version
See Usage Policy.

PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We simulate the performance of a new type of instrument, a Superconducting Multi-Object Spectrograph (SuperMOS), that uses microwave kinetic inductance detectors (MKIDs). MKIDs, a new detector technology, feature good quantum efficiency in the UVOIR, can count individual photons with microsecond timing accuracy, and, like X-ray calorimeters, determine their energy to several percent. The performance of Giga-z, a SuperMOS designed for wide field imaging follow-up observations, is evaluated using simulated observations of the COSMOS mock catalog with an array of 100,000 R_(423 nm) = E/ΔE = 30 MKID pixels. We compare our results against a simultaneous simulation of LSST observations. In 3 yr on a dedicated 4 m class telescope, Giga-z could observe ≈2 billion galaxies, yielding a low-resolution spectral energy distribution spanning 350–1350 nm for each; 1000 times the number measured with any currently proposed LSST spectroscopic follow-up, at a fraction of the cost and time. Giga-z would provide redshifts for galaxies up to z ≈ 6 with magnitudes m_i ≾ 25, with accuracy σ_(Δz/(1 + z)) ≈ 0.03 for the whole sample, and σ_(Δz/(1 + z)) ≈ 0.007 for a select subset. We also find catastrophic failure rates and biases that are consistently lower than for LSST. The added constraint on dark energy parameters for WL + CMB by Giga-z using the FoMSWG default model is equivalent to multiplying the LSST Fisher matrix by a factor of α = 1.27 (w_p), 1.53 (w_a), or 1.98 (Δγ). This is equivalent to multiplying both the LSST coverage area and the training sets by α and reducing all systematics by a factor of 1/√ α, advantages that are robust to even more extreme models of intrinsic alignment.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper DOIArticle
Hirata, Chris0000-0002-2951-4932
Additional Information:© 2013 The American Astronomical Society. Received 2012 November 27; accepted 2013 July 15; published 2013 August 29. D.M. was supported by a grant from the Keck Institute for Space Studies. C.H. was supported by DOE DOE.DESC0006624, and the David and Lucile Packard Foundation. The authors would like to thank G. Brammer, J. Zoubian, T. Treu, and W. Spinella for their assistance.
Group:Keck Institute for Space Studies
Funding AgencyGrant Number
Keck Institute for Space Studies (KISS)UNSPECIFIED
Department of Energy (DOE)DE-SC0006624
David and Lucile Packard FoundationUNSPECIFIED
Subject Keywords:dark energy; galaxies: distances and redshifts; gravitational lensing: weak; instrumentation: detectors; surveys; techniques: imaging spectroscopy
Issue or Number:1
Record Number:CaltechAUTHORS:20131015-093135270
Persistent URL:
Official Citation:Danica W. Marsden et al. 2013 ApJS 208 8 doi:10.1088/0067-0049/208/1/8
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41914
Deposited By: Tony Diaz
Deposited On:15 Oct 2013 16:43
Last Modified:10 Nov 2021 04:35

Repository Staff Only: item control page