The ALMA Spectroscopic Survey in the HUDF: Constraining Cumulative CO Emission at 1 ≲ z ≲ 4 with Power Spectrum Analysis of ASPECS LP Data from 84 to 115 GHz
Journal
Date Issued
2019
Author(s)
Uzgil, Bade D.
•
Carilli, Chris
•
Lidz, Adam
•
Walter, Fabian
•
Thyagarajan, Nithyanandan
•
•
Aravena, Manuel
•
Bertoldi, Frank
•
Cortes, Paulo C.
•
González-López, Jorge
•
Inami, Hanae
•
Popping, Gergö
•
Riechers, Dominik A.
•
Van der Werf, Paul
•
Wagg, Jeff
•
Weiss, Axel
Abstract
We present a power spectrum analysis of the ALMA Spectroscopic Survey Large Program (ASPECS LP) data from 84 to 115 GHz. These data predominantly probe small-scale fluctuations (k = 10-100 h Mpc-1) in the aggregate CO emission in galaxies at 1≲ z ≲ 4. We place an integral constraint on CO luminosity functions (LFs) in this redshift range via a direct measurement of their second moments in the three-dimensional (3D) autopower spectrum, finding a total CO shot-noise power {P}CO,{CO}}({k}CO(2-1)})≤slant 1.9× {10}2 μK2 (Mpc h -1)3. This upper limit (3σ) is consistent with the observed ASPECS CO LFs in Decarli et al. but rules out a large space in the range of {P}CO,{CO}}({k}CO(2-1)}) inferred from these LFs, which we attribute primarily to large uncertainties in the normalization Φ* and knee L * of the Schechter-form CO LFs at z > 2. Also, through power spectrum analyses of ASPECS LP data with 415 positions from galaxies with available optical spectroscopic redshifts, we find that contributions to the observed mean CO intensity and shot-noise power of MUSE galaxies are largely accounted for by ASPECS blind detections. Finally, we sum the fluxes from individual blind CO detections to yield a lower limit on the mean CO surface brightness at 99 GHz of < {T}CO}> =0.55+/- 0.02 μK, which we estimate represents 68%-80% of the total CO surface brightness at this frequency.
Volume
887
Issue
1
Start page
37
Issn Identifier
0004-637X
Ads BibCode
2019ApJ...887...37U
Rights
open.access
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